Subretinal fluid is common in experimental non-arteritic anterior ischemic optic neuropathy

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Yu, C; Ho, J K; Liao, Y J

2014-01-01

Purpose Anterior ischemic optic neuropathy (AION) is an important cause of acute vision loss for which several animal models exist. It has been associated with subretinal fluid in a previous study on patients but not yet so in animal models. Patients and Methods A patient presented with acute non-arteritic AION (NAION) and underwent ophthalmic evaluation and testing including fluorescein angiography and spectral-domain optical coherence tomography (SD-OCT). On the basis of the patient's findings, we used SD-OCT circular and volume scans to analyze retinal changes in a murine model of NAION. Results One week after left eye vision loss, the patient had clinical and imaging findings consistent with NAION. On SD-OCT, there was prominent peripapillary retinal thickening consistent with intra-retinal edema and sub-foveolar fluid. Inspired by the findings in human AION, we looked for similar changes in murine NAION using SD-OCT. The circular scan did not adequately detect the presence of subretinal fluid. Using the 25-line scan, which covered a larger part of the posterior pole, we found that 100% of murine AION resulted in subretinal fluid at day 1. The subretinal fluid resolved by week 1. Conclusion This study detailed a case of clinical NAION associated with intra-retinal and subretinal fluid. We also found that subretinal fluid was common in murine photochemical thrombosis model of AION and could be found far away from the optic disc. PMID:25257770

Subretinal Hemorrhage after Photodynamic Therapy for Juxtapapillary Retinal Capillary Hemangioma

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Takayuki Baba

2011-04-01

Full Text Available A 75-year-old Japanese woman presented with a juxtapapillary retinal capillary hemangioma (RCH in her left eye. Twelve months after the initial examination, the size of the hemangioma had increased and the exudation from the RCH involved the macula. Her best-corrected visual acuity (BCVA had decreased from 0.8 to 0.3. A total of five intravitreal injections of bevacizumab (IVB; 1.25 mg was given but the RCH did not respond. A photodynamic therapy (PDT was done using multiple laser spots to avoid damaging the optic nerve head. After the first PDT, the subfoveal fluid was reduced but not completely gone. One week after the second PDT, a massive subretinal hemorrhage developed. The subretinal hemorrhage was successfully displaced by injecting intraocular sulfur hexafluoride (SF6 gas. At the 3-year follow-up examination, no subretinal hemorrhage or fluid was observed at the macula and the BCVA remained at 0.05. Our case was resistant to the combination of anti-vascular endothelial growth factor (VEGF and PDT and had a rare massive subretinal hemorrhage. A further collection of RCH cases treated with anti-VEGF and PDT that would justify this treatment is necessary.

Argon laser choroidotomy for drainage of subretinal fluid.

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Bovino, J A; Marcus, D F; Nelsen, P T

1985-03-01

We used the argon laser to perforate the choroid and drain subretinal fluid during retinal detachment surgery in 24 consecutive patients. The procedure was successful in 23 of 24 patients (95.8%). The laser settings required for perforation ranged from 0.02 to 0.2 s and from 200 mW to 2.0 W. Because it is not necessary to enter the subretinal space with a solid, pointed object, laser choroidotomy may reduce the incidence of retinal perforation. In addition, the laser has the advantage of cauterizing small vessels during choroidal puncture, which may reduce bleeding at the time of drainage.

Valsalva-Related Subretinal Hemorrhage as a Presenting Symptom of Polypoidal Choroidal Vasculopathy

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Yousif Subhi

2017-01-01

Full Text Available Purpose. To describe a case of Valsalva-related subretinal hemorrhage as a presenting symptom of polypoidal choroidal vasculopathy (PCV. The patient refrained from treatment against our best advice, and thus this is also a rare case of the natural course of an untreated PCV. Methods. Case report. Results. A 66-year-old female with a respiratory infection coughed intensely until exhaustion, after which she developed visual symptoms on the right eye. Primary care ophthalmologist examined the patient on the same day of the onset of symptoms and referred her to our tertiary medical retinal service for detailed retinal diagnosis including fluorescein and indocyanine green angiography. The right eye had a large subretinal hemorrhage and pigment epithelium detachment in the lower temporal arcade with foveal involvement. Against our best advice, the patient refused treatment. In the following 9 months, the BCVA decreased from 68 to 55 ETDRS letters, the subretinal hemorrhage almost regressed, pigment epithelium detachments persisted, and macular edema, intraretinal cysts, and subretinal fibrosis developed. Conclusions. Although classic Valsalva retinopathy with preretinal hemorrhage in most cases can be managed by careful observation and no treatment, this case demonstrates that Valsalva-related subretinal hemorrhage needs different attention and approach.

Autofluorescence from the outer retina and subretinal space: hypothesis and review.

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Spaide, Richard

2008-01-01

To review the pathophysiologic principles underlying increased autofluorescence from the outer retina and subretinal space using selected diseases as examples. The ocular imaging information and histopathologic features, when known, were integrated for diseases causing increased autofluorescence from the outer retina and subretinal space. Inferences were taken from this information and used to create a classification scheme. These diseases are principally those that cause separation of the outer retina from the retinal pigment epithelium, thereby preventing proper phagocytosis of photoreceptor outer segments. The separation can arise from increased exudation into the subretinal space or inadequate removal of fluid from the subretinal space. Lack of normal outer segment processing initially leads to increased accumulation of outer segments on the outer retina and subretinal space. Over time, this material is visible as an increasingly thick coating on the outer retina, is yellow, and is autofluorescent. Over time, atrophy develops with thinning of the deposited material and decreasing autofluorescence. The accumulated material is ultimately capable of inducing damage to the retinal pigment epithelium. Diseases causing accumulation of the material include central serous chorioretinopathy, vitelliform macular dystrophy, acute exudative polymorphous vitelliform maculopathy, choroidal tumors, and vitreomacular traction syndrome. The physical separation of the retinal outer segments from the retinal pigment epithelium hinders proper phagocytosis of the outer segments. Accumulation of the shed but not phagocytized outer segments plays a role in disease manifestations for a number of macular diseases.

Ultrastructural and clinical evidence of subretinal debris accumulation in type 2 macular telangiectasia.

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Cherepanoff, Svetlana; Killingsworth, Murray C; Zhu, Meidong; Nolan, Timothy; Hunyor, Alex P; Young, Stephanie H; Hageman, Gregory S; Gillies, Mark C

2012-11-01

To describe subretinal debris found on ultrastructural examination in an eye with macular telangiectasia (MacTel) type 2 and on optical coherence tomography (OCT) in a subset of patients with MacTel type 2. Blocks from the mid-periphery and temporal perifovea of an eye with clinically documented MacTel type 2 were examined with electron microscopy (EM). Cases came from the Sydney centre of the MacTel project and the practices of the authors. On EM examination, subretinal debris was found in the perifovea with accumulation of degenerate photoreceptor elements in the subretinal space. Despite the substantial subretinal debris, there was minimal retinal pigment epithelial (RPE) reaction. Focal defects were seen in the inner limiting membrane in the perifovea. Of the 65 Sydney MacTel project participants, three (5%) had prominent yellow material at the fovea. OCT revealed smooth mounds between the RPE and the ellipsoid region. The material was hyperautofluorescent. This study suggests that subretinal accumulation of photoreceptor debris may be a feature of MacTel type 2. Ultrastructural and OCT evidence of disease beyond the vasculature, involving photoreceptors and Muller cells, is presented.

Bilateral endogenous Candida albicans subretinal abscess with suspected mixed bacterial infection

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Arai Y

2014-10-01

Full Text Available Yusuke Arai,1 Yukihiro Sato,1 Atsushi Yoshida,1 Hidetoshi Kawashima,1 Toshikatsu Kaburaki,2 Harumi Gomi3 1Department of Ophthalmology, Jichi Medical University, Tochigi, Japan; 2Department of Ophthalmology, The University of Tokyo, Graduate School of Medicine, Tokyo, Japan; 3Center for Clinical Infectious Diseases, Jichi Medical University, Tochigi, Japan Purpose: Candida albicans subretinal abscess is extremely rare. To our knowledge, only one unilateral case has been reported. Herein, we report one bilateral case. Mixed bacterial infection was also suspected based on broad-range real-time polymerase chain reaction.Methods: A 64-year-old man being treated with oral corticosteroids for interstitial pneumonia visited us for visual loss in the left eye. Best corrected visual acuity (BCVA was 20/20 in the right eye and 8/200 in the left eye. Funduscopy revealed round yellowish-white subretinal lesions with retinal hemorrhage in both eyes.Results: Broad-range polymerase chain reaction of the vitreous fluid from the left eye showed a high copy count of bacterial 16s ribosome RNA. Despite large doses of antibiotics, the abscess expanded and vision decreased to light perception in the left eye. Exenteration of the left eye was performed followed by microscopic examination showing Gram-negative bacilli, and C. albicans was also cultured. Antibiotics and the maximum doses of antifungal drugs were administered. However, the abscess in the right eye expanded, and BCVA decreased to 2/200. Vitrectomy and silicone oil tamponade were performed. Vitreous fluid culture revealed C. albicans. At 16 months follow-up, BCVA was stable at 4/200 with healing of the subretinal abscess under silicone oil.Conclusion: Since C. albicans subretinal abscess is extremely rare and there was a concurrent mixed bacterial infection, diagnostic procedures in our bilateral case were more complicated than usual. C. albicans infection should be included in the differential diagnosis

Incidence and evolution of subretinal precipitates in optic disc pit maculopathy.

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Chatziralli, Irini; Theodossiadis, George; Brouzas, Dimitrios; Theodossiadis, Panagiotis

2017-06-26

To study the evolution of subretinal precipitates coexistent with optic disc pit (ODP) maculopathy from their appearance at baseline examination until their absorption after successful treatment. Participants in this retrospective, multicenter study were 42 patients with ODP maculopathy, in whom complete ocular examination was performed, including visual acuity (VA) measurement, slit-lamp examination, color or red-free fundus photography, and optical coherence tomography at baseline after surgical treatment. Out of 42 cases, 17 (40.5%) cases of ODP maculopathy, which were examined between 2002 and 2015, were found to have subretinal precipitates associated with multilayer fluid accumulation at baseline. Precipitates were located at the outer part of the photoreceptor layer and remained for 3-6 months after successful treatment and absorption of subretinal fluid. The mean VA was 0.99 ± 0.21 logMAR at baseline and improved to 0.54 ± 0.25 logMAR at the final examination. Macular precipitates in association with signs of disease chronicity, such as multilayer fluid accumulation, became evident at baseline examination. Precipitates' disappearance in 15 out of 17 cases coincided with the absorption of subretinal fluid. The relative low VA at baseline probably could be attributed to the chronicity of the disease.

Effects of Enhanced Oxygen Delivery by Perfluorocarbons in Spinal Cord Injury

Science.gov (United States)

2013-10-01

indicator of spinal cord ischemia. Acta Med Okayama 1997; 51:71–77. 10. Daugherty WP, Levasseur JE, Sun D, Spiess BD, Bullock MR: Perfluorocarbon... Spiess B. Perflurocarbon emulsions as a promising technology: a review of tissue and vascular gas dynamics. J Appl Physiol 2009; 106: 1444–1452. 12...Neurosurg Spine. 2008; 2: 213-20. 13. Zhou Z, Sun D, Levasseur JE, Merenda A, Hamm RJ, Zhu J, Spiess BD, Bullock MR. Perfluorocarbon emulsions improve

Scleral electrocautery and its effects on choroid vessels: implications for subretinal fluid drainage during scleral buckling surgery.

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Roybal, C Nathaniel; Tsui, Irena; Sanfilippo, Christian; Hubschman, Jean-Pierre

2013-01-01

External drainage of subretinal fluid as part of a scleral buckling procedure rapidly restores the retinal pigment epithelium-neural retina interface in rhegmatogenous retinal detachments but carries the inherent risk of subretinal hemorrhage and retinal incarceration. The authors investigated variations to the technique to reduce the chance of subretinal hemorrhage originating from the choroid. A novel method for needle drainage using electrocautery of the sclerochoroidal layers before puncture was employed. The effect of 0% to 50% scleral electrocautery in a porcine model was investigated. A significant decrease in choroidal vessel diameter and choroidal vessel density at 40% electrocautery was demonstrated. Electrocautery without scleral cut-down before external drainage of subretinal fluid likely decreases the chance of subretinal hemorrhage by decreasing choroidal vascularity. Copyright 2013, SLACK Incorporated.

Intraoperative Macula Protection by Perfluorocarbon Liquid for the Metallic Intraocular Foreign Body Removal during 23-Gauge Vitrectomy

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Robert Rejdak

2017-01-01

Full Text Available Purpose. To evaluate visual and safety outcomes of 23-gauge (G pars plana vitrectomy (PPV with application of perfluorocarbon liquid (PFCL for intraoperative protection of the macula during intraocular foreign body (IOFB removal. Methods. Retrospective study of 42 patients who underwent 23 G PPV for IOFB removal from posterior segment with intraoperative PFCL application for the macula shielding. Collected data included corrected distance visual acuity (CDVA, size of IOFB, and complication rate. The mean follow-up period was 12 months. Results. The mean preoperative CDVA was 0.54 logMAR (SD 0.46, and the final mean CDVA was 0.68 logMAR (SD 0.66. All IOFBs were metallic with mean dimensions of 4.6 mm × 2.1 mm. Twenty-two IOFBs were removed through the corneal tunnel and 20 IOFBs through the sclerotomy. No intraoperative iatrogenic lesion of the macula was observed. As a tamponade, silicon oil was applied in 31 eyes, SF6 gas in 5 eyes, air in 4 eyes, and 2 eyes required no tamponade. Secondary retinal detachment was observed in 17% of cases, but at the end of the follow-up, all the retinas were attached. Conclusion. PFCL application during PPV is a safe method of protecting the macula from unexpected falling of the metallic IOFB during its removal.

A rare case of traumatic subretinal migration of crystalline lens, corroborated histologically.

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Bawankar, Pritam; Das, Dipankar; Agarwal, Balmukund; Bhattacharjee, Kasturi; Tayab, Shahinur; Deka, Panna; Singh, Anshul; Borah, Erani; Dhar, Shriya

2017-12-01

Blunt trauma is the most common cause of posterior dislocation of the crystalline lens. We describe a rare case of subretinal migration of crystalline lens through the giant retinal tear following blunt ocular trauma. This incidental finding of subretinal dislocation of lens following blunt ocular trauma was confirmed on histopathological examination of the enucleated eye. This complication has not been described by histopathological examination in literature so far.

A rare case of traumatic subretinal migration of crystalline lens, corroborated histologically

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Pritam Bawankar

2017-01-01

Full Text Available Blunt trauma is the most common cause of posterior dislocation of the crystalline lens. We describe a rare case of subretinal migration of crystalline lens through the giant retinal tear following blunt ocular trauma. This incidental finding of subretinal dislocation of lens following blunt ocular trauma was confirmed on histopathological examination of the enucleated eye. This complication has not been described by histopathological examination in literature so far.

The relation between bevacizumab injection and the formation of subretinal fibrosis in diabetic patients with panretinal photocoagulation.

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Batman, Cosar; Ozdamar, Yasemin

2010-01-01

To report the development of subretinal fibrosis after the injection of intravitreal bevacizumab in eyes with proliferative diabetic retinopathy (PDR) refractory to panretinal laser photocoagulation (PRP). Twenty-one eyes of 15 patients treated with PRP and intravitreal injection of bevacizumab were included in this study. The clinical outcomes of 21 eyes having subretinal fibrosis after intravitreal bevacizumab injection were reviewed. There were 9 men and 6 women with a mean age of 51.3 +/- 8.9 years. All eyes had PDR refractory to panretinal photocoagulation and were treated with at least one intravitreal injection of 1.25 mg of bevacizumab (mean number of injections: 1.8). Before injection, there was subretinal fibrosis in 5 eyes and vitreoretinal traction in 19 eyes. After a mean follow-up period of 7 months, the development or progression of subretinal fibrosis was detected in all eyes. Intravitreal injection of bevacizumab may cause formation or progression of subretinal fibrosis in patients with PDR refractory to PRP. Copyright 2010, SLACK Incorporated.

Early Subretinal Allograft Rejection Is Characterized by Innate Immune Activity.

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Kennelly, Kevin P; Holmes, Toby M; Wallace, Deborah M; O'Farrelly, Cliona; Keegan, David J

2017-06-09

Successful subretinal transplantation is limited by considerable early graft loss despite pharmacological suppression of adaptive immunity. We postulated that early innate immune activity is a dominant factor in determining graft survival and chose a nonimmunosuppressed mouse model of retinal pigment epithelial (RPE) cell transplantation to explore this. Expression of almost all measured cytokines by DH01 RPE cells increased significantly following graft preparation, and the neutrophil chemoattractant KC/GRO/CINC was most significantly increased. Subretinal allografts of DH01 cells (C57BL/10 origin) into healthy, nonimmunosuppressed C57BL/6 murine eyes were harvested and fixed at 1, 3, 7, and 28 days postoperatively and subsequently cryosectioned and stained. Graft cells were detected using SV40 large T antigen (SV40T) immunolabeling and apoptosis/necrosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Sections were also immunolabeled for macrophage (CD11b and F4/80), neutrophil (Gr1 Ly-6G), and T-lymphocyte (CD3-ɛ) infiltration. Images captured with an Olympus FV1000 confocal microscope were analyzed using the Imaris software. The proportion of the subretinal bolus comprising graft cells (SV40T+) was significantly (p < 0.001) reduced between postoperative day (POD) 3 (90 ± 4%) and POD 7 (20 ± 7%). CD11b+, F4/80+, and Gr1 Ly-6G+ cells increased significantly (p < 0.05) from POD 1 and predominated over SV40T+ cells by POD 7. Colabeling confocal microscopic analysis demonstrated graft engulfment by neutrophils and macrophages at POD 7, and reconstruction of z-stacked confocal images confirmed SV40T inside Gr1 Ly-6G+ cells. Expression of CD3-ɛ was low and did not differ significantly between time points. By POD 28, no graft cells were detectable and few inflammatory cells remained. These studies reveal, for the first time, a critical role for innate immune mechanisms early in subretinal graft rejection. The future success

Chemical and radiolytical characterization of some perfluorocarbon fluids used as coolants for LHC experiments

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Battistin, M; Setnescu, R; Teissandier, B; CERN. Geneva. TS Department

2006-01-01

Perfluorocarbon fluids, - mainly C6F14 - used as coolants within High Energy Physics Detectors in the Large Hadrons Collider (LHC) at CERN, were characterized by applying mainly the following methods: GC, FT-IR and UV-Vis. The aim of this work was the quality control, the identification and the quantification of different impurities which could increase the radiation sensitivity of these fluids. Thus, the presence of H containing molecules within perfluorocarbons strongly influences the appearance of hydrofluoric acid during their irradiation. The procedures settled-up in this work are sensitive to the presence of such impurities and would be used for the analyses of the received perfluorocarbon fluids as well as to assess the radiation induced modifications and the efficiency of their purification treatments.

[Initial subretinal localization of acute myeloblastic leukemia (AML5) recurrence].

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Le Gall, S; François, S; Urier, N; Genevieve, F; d'Hermies, F; Rachieru, P; Ifrah, N

2001-10-13

Reduced visual acuity in patients with acute leucemia can result from many causes including an ocular localization. A patient previously treated for acute myeloblastic leucemia-5 (AML5) developed bilateral vision impairment related to a subretinal localization of the leucemia. Meningeal and bone marrow relapse followed. The subretinal localization responded only to massive systemic steroid treatment. Although asymptomatic, ocular localizations are frequent in leucemia. Their prognostic impact depends on the ocular structure involved and on the chronology of onset--early or late in the leucemia course. The underlying pathophysiological mechanism of ocular involvement remains unexplained but hyperleucocytosis at presentation may be a risk factor and would justify at least systematic specialized examinations and discussion of prophylactic treatment.

Association between Antiplatelet or Anticoagulant Drugs and Retinal/subretinal Hemorrhage in the Comparison of AMD Treatments Trials (CATT)

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Ying, Gui-shuang; Maguire, Maureen G.; Daniel, Ebenezer; Grunwald, Juan E; Ahmed, Osama; Martin, Daniel F.

2015-01-01

Objective To evaluate the association between use of antiplatelet (AP) or anticoagulant (AC) drugs and retinal/subretinal hemorrhage in participants with neovascular age-related macular degeneration (AMD) in the Comparison of AMD Treatments Trials (CATT). Design Cohort study within CATT. Methods 1185 CATT participants with untreated active neovascular AMD were interviewed for use of AP/AC drugs. Trained readers evaluated photographs for the presence and size of retinal/subretinal hemorrhage associated with the neovascular lesion at baseline and years 1 and 2. Associations between use of AP/AC drugs and hemorrhage were evaluated among all participants and by baseline hypertension status using Fisher exact test and multivariate logistic regression models. Main Outcome Measures Odds ratio for association with AP/AC use. Results Among 1165 participants with gradable photographs, 724 (62.1%) had retinal/subretinal hemorrhage at baseline, 84.4% of hemorrhages were ≤ 1 DA, 8.1% were 1 to 2 DA, and 7.5% were >2 DA. 608 (52.2%) participants used AP/AC drugs at baseline, including 514 (44.1%) AP only, 77 (6.6%) AC only, and 17 (1.5%) both AP and AC. Participants with retinal/subretinal hemorrhage at baseline were comparable to those without retinal/subretinal hemorrhage except that they were older (80 vs. 78 years, phemorrhage was present in 64.5% of AP/AC users and in 59.6% of non-users (p=0.09), the adjusted odds ratio (OR) was 1.18 (95% CI: 0.91–1.51, p=0.21). Neither presence nor size of baseline retinal/subretinal hemorrhage was associated with the type, dose or duration of AP/AC use. Forty-four (4.08%) of 1078 participants had retinal/subretinal hemorrhage detected on 1-year or 2-year photographs; these hemorrhages were not associated with AP/AC use at baseline (p=0.28) or during follow-up (p=0.64). Among participants with hypertension (N=807), AP/AC use was associated with higher rate of retinal/subretinal hemorrhage at baseline (66.8% vs. 56.4%, adjusted OR=1

Case Report of Optic Disc Drusen with Simultaneous Peripapillary Subretinal Hemorrhage and Central Retinal Vein Occlusion

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David Zhiwei Law

2014-01-01

Full Text Available A 52-year-old Chinese gentleman presented with right eye floaters and photopsia over one week. His visual acuities were 20/20 bilaterally. Posterior segment examination showed a right eye swollen optic disc and central retinal vein occlusion (CRVO associated with an area of subretinal hemorrhage adjacent to the optic disc. Fundus fluorescein (FA and indocyanine green angiographies (ICGA of the right eye did not demonstrate choroidal neovascularization (CNV, polypoidal choroidal vasculopathy (PCV, or retinal ischemia. Ultrasound B-scan revealed optic disc drusen (ODD. In view of good vision and absence of CNV, he was managed conservatively with spontaneous resolution after two months. Commonly, ODD may directly compress and mechanically rupture subretinal vessels at the optic disc, resulting in peripapillary subretinal hemorrhage, as was likely the case in our patient. Mechanical impairment of peripapillary circulation also results in retinal ischemia and may trigger the development of choroidal neovascularization (CNV and/or polypoidal choroidal vasculopathy (PCV, leading to subretinal haemorrhage. Compromise in central venous outflow with increased retinal central venous pressure from the direct mechanical effects of enlarging ODD results in central retinal vein occlusion (CRVO. Patients with subretinal hemorrhage and CRVO from ODD should be monitored closely for the development of potentially sight-threatening complications.

Spectral domain optical coherence tomography imaging of subretinal bands associated with chronic retinal detachments

OpenAIRE

Kothari, Nikisha; Kuriyan, Ajay E; Flynn, Harry W

2016-01-01

Nikisha Kothari, Ajay E Kuriyan, Harry W Flynn JrDepartment of Ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USAAbstract: We report three patients with subretinal bands associated with retinal detachment in chronic retinal detachments who underwent successful retinal reattachment. Subretinal bands before and after surgery can be identified on clinical examination and spectral domain optical coherence tomography. Removal of subr...

Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS.

Science.gov (United States)

Stingl, Katarina; Bartz-Schmidt, Karl Ulrich; Besch, Dorothea; Braun, Angelika; Bruckmann, Anna; Gekeler, Florian; Greppmaier, Udo; Hipp, Stephanie; Hörtdörfer, Gernot; Kernstock, Christoph; Koitschev, Assen; Kusnyerik, Akos; Sachs, Helmut; Schatz, Andreas; Stingl, Krunoslav T; Peters, Tobias; Wilhelm, Barbara; Zrenner, Eberhart

2013-04-22

This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm(2) chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s(-1)), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037° or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (n = 8; p tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant's power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.

Results of laser treatment for sub-retinal neovascular membranes

African Journals Online (AJOL)

1990-09-01

Sep 1, 1990 ... haemonhagic detachment of the retinal pigment epithelium and sensory· retina produced by exudation from these new vessels.I-l This exudative and sometimes haemorrhagic process often leads to severe and permanent loss of central vision because of sub-retinal fibrovascular organisation.2 Progressive.

Liquid Ventilation

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Qutaiba A. Tawfic

2011-01-01

Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

Benefit of spatial filtering for visual perception with a subretinal implant.

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Rieger, Viola; Aryan, Naser Pour; Brendler, Christian; Rothermel, Albrecht

2014-01-01

Subretinal implants have proven to be capable of restoring vision to patients suffering from hereditary retinal degeneration diseases like retinitis pigmentosa and cone-rod dystrophy. Although they already provide basic visual perception, there is still much room for improvement in this field. Effects like electric field interference limit the visual acuity and may be the cause of the perceived vision to be blurred. This influence could be reduced by means of highpass spatial filtering. In this paper, based on the available reports about the visual perception parameters from the patients using the alpha-IMS subretinal implant, a model for the blurring effect of the patients retina is proposed. On this basis, highpass filters are suggested which will compensate the obscuring effect of the stimulator device plus retina system to some extent.

Extraocular surgery for implantation of an active subretinal visual prosthesis with external connections: feasibility and outcome in seven patients.

Science.gov (United States)

Besch, D; Sachs, H; Szurman, P; Gülicher, D; Wilke, R; Reinert, S; Zrenner, E; Bartz-Schmidt, K U; Gekeler, F

2008-10-01

Due to low energy levels in microphotodiode-based subretinal visual prostheses, an external power supply is mandatory. We report on the surgical feasibility and the functional outcome of the extraocular part of an approach to connect a subretinal prosthesis to an extracorporeal connector in the retro-auricular space via a trans-scleral, transchoroidal cable. Seven volunteers with retinitis pigmentosa received an active subretinal implant; energy was supplied by gold wires on a trans-sclerally, transchoroidally implanted polyimide foil leading to the lateral orbital rim where it was fixated and connected to a silicone cable. The cable was implanted subperiostally beneath the temporal muscle using a trocar to the retro-auricular space where it penetrated the skin for connection to a stimulator. To avoid subretinal movement of the implant, three tension relief points have been introduced. All implantations were performed as planned without complications, and no serious adverse events occurred in the postoperative period. Fixation of the implants was stable throughout the entire study duration of 4 weeks; permanent skin penetration proved to be uncomplicated. Motility was minimally restricted in downgaze and ab-/adduction. Explantation was uneventful. The above-described procedure provides a method for stable fixation of a subretinal device with a trans-scleral, transchoroidal cable connection to an extracorporeal connector.

Subretinal Fluid Drainage and Vitrectomy Are Helpful in Diagnosing and Treating Eyes with Advanced Coats' Disease

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Ayako Imaizumi

2016-04-01

Full Text Available Severe forms of Coats’ disease are often associated with total retinal detachment, and a differential diagnosis from retinoblastoma is critically important. In such eyes, laser- and/or cryoablation is often ineffective or sometimes impossible to perform. We report a case of advanced Coats’ disease in which a rapid pathological examination of subretinal fluid was effective for the diagnosis, and external subretinal drainage combined with vitrectomy was effective in preserving the eye.

Functional outcome in subretinal electronic implants depends on foveal eccentricity.

Science.gov (United States)

Stingl, Katarina; Bartz-Schmidt, Karl-Ulrich; Gekeler, Florian; Kusnyerik, Akos; Sachs, Helmut; Zrenner, Eberhart

2013-11-19

An active microelectronic subretinal implant, developed to replace the photoreceptive function in hereditary degenerations of the outer retina, has been applied in a pilot and clinical study in patients with end-stage retinal degeneration. The study population comprised 20 blind patients, all of whom lost vision as result of a hereditary retinal disease. An active visual implant was placed surgically within the subretinal space of each patient: subfoveal placement in eight patients (group 1) and parafoveal placement in 12 (group 2). Standardized low-vision tests, including light perception, light localization, movement detection, grating acuity, and visual acuity by Landolt C-rings, were used under masked, randomized implant-OFF and implant-ON conditions. For the chip-mediated vision functional results of both subject groups were compared. Three of 20 patients were excluded from analysis because of surgical or technical implant issues. Among patients with nonfoveal placement of the implant, 80% could perceive light, 10% recognized location, and 10% correctly distinguished stripe patterns up to a resolution of 0.33 cycles/degree. No nonfoveal placement patient passed the motion or Landolt C-ring tests. When the implant was placed subfoveally, 100% of patients could perceive light and determine light localization, 75% could resolve motion up to 35°/s, 88% correctly distinguished stripe patterns up to a resolution of 3.3 cycles/degree, and 38% passed a Landolt C-ring test with a decimal visual acuity of up to 20/546 (logMAR 1.43). Subfoveal placement of active subretinal visual implants allows superior measurable outcomes compared to para- or nonfoveal placement locations. (ClinicalTrials.gov numbers, NCT01024803, NCT00515814.).

Spontaneous resorption of sub-retinal cortical lens material

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Salil S Gadkari

2014-01-01

Full Text Available We report a rare case of retained sub-retinal cortical material, which underwent spontaneous resorption. Patient presented with a left eye traumatic retinal detachment with a large retinal tear and posteriorly dislocated cataractous lens. Vitrectomy, lensectomy, silicone oil injection, and endolaser were performed. A good visual result was achieved. The report draws attention to this condition and highlights possible technique for minimizing risk of this complication in similar cases.

Subretinally transplanted embryonic stem cells rescue photoreceptor cells from degeneration in the RCS rats.

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Schraermeyer, U; Thumann, G; Luther, T; Kociok, N; Armhold, S; Kruttwig, K; Andressen, C; Addicks, K; Bartz-Schmidt, K U

2001-01-01

The Royal College of Surgeons (RCS) rat is an animal model for retinal degeneration such as the age-related macular degeneration. The RCS rat undergoes a progressive retinal degeneration during the early postnatal period. A potential treatment to prevent this retinal degeneration is the transplantation into the subretinal space of cells that would replace functions of the degenerating retinal pigment epithelium (RPE) cells or may form neurotrophic factors. In this study we have investigated the potential of subretinally transplanted embryonic stem cells to prevent the genetically determined photoreceptor cell degeneration in the RCS rat. Embryonic stem cells from the inner cell mass of the mouse blastocyst were allowed to differentiate to neural precursor cells in vitro and were then transplanted into the subretinal space of 20-day-old RCS rats. Transplanted and sham-operated rats were sacrificed 2 months following cell transplantation. The eyes were enucleated and photoreceptor degeneration was quantified by analyzing and determining the thickness of the outer nuclear layer by light and electron microscopy. In the eyes transplanted with embryonic cells up to 8 rows of photoreceptor cell nuclei were observed, whereas in nontreated control eyes the outer nuclear layer had degenerated completely. Transplantation of embryonic stem cells appears to delay photoreceptor cell degeneration in RCS rats.

Functionality of albumin-derived perfluorocarbon-based artificial oxygen carriers in the Langendorff-heart †.

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Wrobeln, Anna; Schlüter, Klaus D; Linders, Jürgen; Zähres, Manfred; Mayer, Christian; Kirsch, Michael; Ferenz, Katja B

2017-06-01

The aim of this study was to prove whether albumin-derived perfluorocarbon-based nanoparticles (capsules) can operate as a novel artificial oxygen carrier in a rat Langendorff-heart perfusion model. Hearts perfused with capsules showed increased left ventricular pressure and rate pressure product compared to hearts perfused with pure Krebs-Henseleit (KH)-buffer. The capsules prevented the myocardium from functional fail when in their absence a noxious ischemia was observed. Capsules did not change rheological properties of KH-buffer and could repeatedly reload with oxygen. This albumin-derived perfluorocarbon-based artificial oxygen carrier preserved the function of rat hearts due to the transport of oxygen in a satisfactory manner. Because of these positive results, the functionality of the applied capsules should be verified in living animals.

Successful subretinal delivery and monitoring of MicroBeads in mice.

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M Dominik Fischer

Full Text Available To monitor viability of implanted genetically engineered and microencapsulated human stem cells (MicroBeads in the mouse eye, and to study the impact of the beads and/or xenogenic cells on retinal integrity.MicroBeads were implanted into the subretinal space of SV126 wild type mice using an ab externo approach. Viability of microencapsulated cells was monitored by noninvasive retinal imaging (Spectralis™ HRA+OCT. Retinal integrity was also assessed with retinal imaging and upon the end of the study by light and electron microscopy. The implanted GFP-marked cells encapsulated in subretinal MicroBeads remained viable over a period of up to 4 months. Retinal integrity and viability appeared unaltered apart from the focal damage due to the surgical implantation, GFAP upregulation, and opsin mistargeting in the immediate surrounding tissue.The accessibility for routine surgery and its immune privileged state make the eye an ideal target for release system implants for therapeutic substances, including neurotrophic and anti-angiogenic compounds or protein based biosimilars. Microencapsulated human stem cells (MicroBeads promise to overcome limitations inherent with single factor release systems, as they are able to produce physiologic combinations of bioactive compounds.

Trans-Corneal Subretinal Injection in Mice and Its Effect on the Function and Morphology of the Retina.

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Yan Qi

Full Text Available To introduce a practical method of subretinal injection in mice and evaluate injection-induced retinal detachment (RD and damage using a dynamic imaging system, electrophysiology, and histology.After full dilation of a 2-month-old C57BL/6J mouse pupil, the cornea near the limbus was punctured with a 30 ½-gague disposable beveled needle. A 33 ½-gauge blunt needle was inserted through the corneal perforation into the anterior chamber, avoiding the lens before going deeper into the vitreous cavity, and penetrating the inner retina to reach the subretinal space. The mice were divided into four groups: in group 1, about 80-100% of the retina was filled with subretinally injected solution; in group 2, approximately 50-70% of the retina was filled with injected solution; in group 3, the procedures were stopped before solution injection; and non-injected eyes were used as the negative control in group 4. An optical coherence tomography (OCT imaging system was used to monitor retinal reattachment during the first three days following the injections. Histological and functional changes were examined by light microscopy and electroretinography (ERG at five weeks post-injection.After a short-term training, a 70% success rate with 50% or more coverage (i.e., retinal blebs occupied 50% or more retinal area and filled with the injected solution with minimal injection-related damages can be achieved. Bleb formation was associated with retinal detachment (RD between the neuroretina and the retinal pigment epithelium (RPE layer. Partial RD could be observed at post-injection day 1, and by day 2 most of the retina had reattached. At 5 weeks post-injection, compared to uninjected control group 4, the b-wave amplitudes of ERG decreased 22% in group 1, 16% in group 2, and 7% in group 3; the b-wave amplitudes were statistically different between the uninjected group and the groups with either 50-70% or 80-100% coverage. The subretinal injection-induced RD reattached

Safety and efficacy of subretinal visual implants in humans: methodological aspects.

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Stingl, Katarina; Bach, Michael; Bartz-Schmidt, Karl-Ulrich; Braun, Angelika; Bruckmann, Anna; Gekeler, Florian; Greppmaier, Udo; Hörtdörfer, Gernot; Kusnyerik, Akos; Peters, Tobias; Wilhelm, Barbara; Wilke, Robert; Zrenner, Eberhart

2013-01-01

Replacing the function of visual pathway neurons by electronic implants is a novel approach presently explored by various groups in basic research and clinical trials. The novelty raises unexplored methodological aspects of clinical trial design that may require adaptation and validation. We present procedures of efficacy and safety testing for subretinal visual implants in humans, as developed during our pilot trial 2005 to 2009 and multi-centre clinical trial since 2010. Planning such a trial requires appropriate inclusion and exclusion criteria. For subretinal electronic visual implants, patients with photoreceptor degeneration are the target patient group, whereas presence of additional diseases affecting clear optic media or the visual pathway must be excluded. Because sham surgery is not possible, a masked study design with implant power ON versus OFF is necessary. Prior to the efficacy testing by psychophysical tests, the implant's technical characteristics have to be controlled via electroretinography (ERG). Moreover the testing methods require adaptation to the particular technology. We recommend standardised tasks first to determine the light perception thresholds, light localisation and movement detection, followed by grating acuity and vision acuity test via Landolt C rings. A laboratory setup for assessing essential activities of daily living is presented. Subjective visual experiences with the implant in a natural environment, as well as questionnaires and psychological counselling are further important aspects. A clinical trial protocol for artificial vision in humans, which leads a patient from blindness to the state of very low vision is a challenge and cannot be defined completely prior to the study. Available tests of visual function may not be sufficiently suited for efficacy testing of artificial vision devices. A protocol based on experience with subretinal visual implants in 22 patients is presented that has been found adequate to monitor

Design of ultrasonically-activatable nanoparticles using low boiling point perfluorocarbons.

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Sheeran, Paul S; Luois, Samantha H; Mullin, Lee B; Matsunaga, Terry O; Dayton, Paul A

2012-04-01

Recently, an interest has developed in designing biomaterials for medical ultrasonics that can provide the acoustic activity of microbubbles, but with improved stability in vivo and a smaller size distribution for extravascular interrogation. One proposed alternative is the phase-change contrast agent. Phase-change contrast agents (PCCAs) consist of perfluorocarbons (PFCs) that are initially in liquid form, but can then be vaporized with acoustic energy. Crucial parameters for PCCAs include their sensitivity to acoustic energy, their size distribution, and their stability, and this manuscript provides insight into the custom design of PCCAs for balancing these parameters. Specifically, the relationship between size, thermal stability and sensitivity to ultrasound as a function of PFC boiling point and ambient temperature is illustrated. Emulsion stability and sensitivity can be 'tuned' by mixing PFCs in the gaseous state prior to condensation. Novel observations illustrate that stable droplets can be generated from PFCs with extremely low boiling points, such as octafluoropropane (b.p. -36.7 °C), which can be vaporized with acoustic parameters lower than previously observed. Results demonstrate the potential for low boiling point PFCs as a useful new class of compounds for activatable agents, which can be tailored to the desired application. Copyright © 2012 Elsevier Ltd. All rights reserved.

In vivo performance of photovoltaic subretinal prosthesis

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Mandel, Yossi; Goetz, George; Lavinsky, Daniel; Huie, Phil; Mathieson, Keith; Wang, Lele; Kamins, Theodore; Manivanh, Richard; Harris, James; Palanker, Daniel

2013-02-01

We have developed a photovoltaic retinal prosthesis, in which camera-captured images are projected onto the retina using pulsed near-IR light. Each pixel in the subretinal implant directly converts pulsed light into local electric current to stimulate the nearby inner retinal neurons. 30 μm-thick implants with pixel sizes of 280, 140 and 70 μm were successfully implanted in the subretinal space of wild type (WT, Long-Evans) and degenerate (Royal College of Surgeons, RCS) rats. Optical Coherence Tomography and fluorescein angiography demonstrated normal retinal thickness and healthy vasculature above the implants upon 6 months follow-up. Stimulation with NIR pulses over the implant elicited robust visual evoked potentials (VEP) at safe irradiance levels. Thresholds increased with decreasing pulse duration and pixel size: with 10 ms pulses it went from 0.5 mW/mm2 on 280 μm pixels to 1.1 mW/mm2 on 140 μm pixels, to 2.1 mW/mm2 on 70 μm pixels. Latency of the implant-evoked VEP was at least 30 ms shorter than in response evoked by the visible light, due to lack of phototransduction. Like with the visible light stimulation in normal sighted animals, amplitude of the implant-induced VEP increased logarithmically with peak irradiance and pulse duration. It decreased with increasing frequency similar to the visible light response in the range of 2 - 10 Hz, but decreased slower than the visible light response at 20 - 40 Hz. Modular design of the photovoltaic arrays allows scalability to a large number of pixels, and combined with the ease of implantation, offers a promising approach to restoration of sight in patients blinded by retinal degenerative diseases.

Xenotransplantation of human neural progenitor cells to the subretinal space of nonimmunosuppressed pigs

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Warfvinge, Karin; Schwartz, Philip H; Kiilgaard, Jens Folke

2011-01-01

To investigate the feasibility of transplanting human neural progenitor cells (hNPCs) to the retina of nonimmunosuppressed pigs, cultured hNPCs were injected into the subretinal space of 5 adult pigs after laser burns were applied to promote donor cell integration. Postoperatively, the retinal ve...

Subretinal drusenoid deposits with increased autofluorescence in eyes with reticular pseudodrusen.

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Lee, Mee Yon; Ham, Don-Il

2014-01-01

To characterize a variant type of drusenoid deposit with different imaging features in comparison to reticular pseudodrusen. Retrospective observational consecutive case series. Eyes showing atypical drusenoid lesions were sorted out from 257 eyes of 133 patients previously diagnosed as reticular pseudodrusen. Eyes were evaluated using color fundus photography, confocal scanning laser ophthalmoscopy, and spectral domain optical coherence tomography. A variant type of drusenoid deposits showing different imaging features from reticular pseudodrusen was found in 17 eyes of 12 patients (6.6%). The mean age of patients was 62.7 ± 11.6 years, and all patients were women. These deposits were observed as yellowish white, round to oval lesions on color photographs, located under the sensory retina and above the retinal pigment epithelium on spectral domain optical coherence tomography similar to reticular pseudodrusen. However, they were present in a smaller number as discrete lesions and showed increased autofluorescence. None of them were accompanied by late age-related macular degeneration. Subretinal drusenoid deposits are not homogeneous and can be classified into two types according to the fundus autofluorescence. Multimodal imaging tests are needed for the differential diagnosis of subretinal drusenoid deposits.

Subretinal posterior pole injury induces selective proliferation of RPE cells in the periphery in in vivo studies in pigs

DEFF Research Database (Denmark)

Kiilgaard, Jens Folke; Prause, Jan U; Prause, Michala

2007-01-01

PURPOSE: To study topographical differences in porcine retinal pigment epithelial (RPE) cell proliferation (1) in vivo, after experimental central surgical subretinal injury, and (2) in vitro. METHODS: Domestic pigs underwent either experimental RPE debridement (n = 5), subretinal amniotic membrane...... cells. This observation was true of both types of experimental surgery performed. In vitro, RPE isolates from the pre-equatorial region consistently yielded higher cell densities than did RPE cell isolates from more central parts of the epithelium. This was apparent through the three first passages...

Subretinal electrical stimulation preserves inner retinal function in RCS rat retina.

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Ciavatta, Vincent T; Mocko, Julie A; Kim, Moon K; Pardue, Machelle T

2013-01-01

Previously, studies showed that subretinal electrical stimulation (SES) from a microphotodiode array (MPA) preserves electroretinography (ERG) b-wave amplitude and regional retinal structure in the Royal College of Surgeons (RCS) rat and simultaneously upregulates Fgf2 expression. This preservation appears to be associated with the increased current produced when the MPA is exposed to ERG test flashes, as weekly ERG testing produces greater neuroprotection than biweekly or no testing. Using an infrared source to stimulate the MPA while avoiding potential confounding effects from exposing the RCS retina to high luminance white light, this study examined whether neuroprotective effects from SES increased with subretinal current in a dose-dependent manner. RCS rats (n=49) underwent subretinal implantation surgery at P21 with MPA devices in one randomly selected eye, and the other eye served as the control. Naïve RCS rats (n=25) were also studied. To increase SES current levels, implanted eyes were exposed to 15 min per session of flashing infrared light (IR) of defined intensity, frequency, and duty cycle. Rats were divided into four SES groups that received ERG testing only (MPA only), about 450 µA/cm2 once per week (Low 1X), about 450 µA/cm2 three times per week (Low 3X), and about 1350 µA/cm2 once per week (High 1X). One eye of the control animals was randomly chosen for IR exposure. All animals were followed for 4 weeks with weekly binocular ERGs. A subset of the eyes was used to measure retina Fgf2 expression with real-time reverse-transcription PCR. Eyes receiving SES showed significant preservation of b-wave amplitude, a- and b-wave implicit times, oscillatory potential amplitudes, and post-receptoral parameters (Vmax and log σ) compared to untreated eyes. All SES-treated eyes had similar preservation, regardless of increased SES from IR light exposure. SES-treated eyes tended to have greater retinal Fgf2 expression than untreated eyes, but Fgf2 expression

Subretinal Fibrosis in Stargardt’s Disease with Fundus Flavimaculatus and ABCA4 Gene Mutation

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Settimio Rossi

2012-12-01

Full Text Available Purpose: To report on 4 patients affected by Stargardt’s disease (STGD with fundus flavimaculatus (FFM and ABCA4 gene mutation associated with subretinal fibrosis. Methods: Four patients with a diagnosis of STGD were clinically examined. All 4 cases underwent a full ophthalmologic evaluation, including best-corrected visual acuity measured by the Snellen visual chart, biomicroscopic examination, fundus examination, fundus photography, electroretinogram, microperimetry, optical coherence tomography and fundus autofluorescence. All patients were subsequently screened for ABCA4 gene mutations, identified by microarray genotyping and confirmed by conventional DNA sequencing of the relevant exons. Results: In all 4 patients, ophthalmologic exam showed areas of subretinal fibrosis in different retinal sectors. In only 1 case, these lesions were correlated to an ocular trauma as confirmed by biomicroscopic examination of the anterior segment that showed a nuclear cataract dislocated to the superior site and vitreous opacities along the lens capsule. The other patients reported a lifestyle characterized by competitive sport activities. The performed instrumental diagnostic investigations confirmed the diagnosis of STGD with FFM in all patients. Moreover, in all 4 affected individuals, mutations in the ABCA4 gene were found. Conclusions: Patients with the diagnosis of STGD associated with FFM can show atypical fundus findings. We report on 4 patients affected by STGD with ABCA4 gene mutation associated with subretinal fibrosis. Our findings suggest that this phenomenon can be accelerated by ocular trauma and also by ocular microtrauma caused by sport activities, highlighting that lifestyle can play a role in the onset of these lesions.

Phase-Change Nanoparticles Using Highly Volatile Perfluorocarbons: Toward a Platform for Extravascular Ultrasound Imaging

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Terry O. Matsunaga, Paul S. Sheeran, Samantha Luois, Jason E. Streeter, Lee B. Mullin, Bhaskar Banerjee, Paul A. Dayton

2012-01-01

Full Text Available Recent efforts using perfluorocarbon (PFC nanoparticles in conjunction with acoustic droplet vaporization has introduced the possibility of expanding the diagnostic and therapeutic capability of ultrasound contrast agents to beyond the vascular space. Our laboratories have developed phase-change nanoparticles (PCNs from the highly volatile PFCs decafluorobutane (DFB, bp =-2 °C and octafluoropropane (OFP, bp =-37 °C for acoustic droplet vaporization. Studies with commonly used clinical ultrasound scanners have demonstrated the ability to vaporize PCN emulsions with frequencies and mechanical indices that may significantly decrease tissue bioeffects. In addition, these contrast agents can be formulated to be stable at physiological temperatures and the perfluorocarbons can be mixed to modulate the balance between sensitivity to ultrasound and general stability. We herein discuss our recent efforts to develop finely-tuned diagnostic/molecular imaging agents for tissue interrogation. We discuss studies currently under investigation as well as potential diagnostic and therapeutic paradigms that may emerge as a result of formulating PCNs with low boiling point PFCs.

Grafting of ARPE-19 and Schwann cells to the subretinal space in RCS rats.

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Wang, Shaomei; Lu, Bin; Wood, Patrick; Lund, Raymond D

2005-07-01

To study the distribution of the human retinal pigment epithelium (hRPE) cell line ARPE-19 and human Schwann (hSC) cells grafted to the subretinal space of the Royal College of Surgeon (RCS) rat and the relation of graft cell distribution to photoreceptor rescue. Cell suspensions of both donor types were injected into the subretinal space of 3-week-old dystrophic RCS rats through a transscleral approach, human fibroblast and medium were used as control grafts. All animals were maintained on oral cyclosporine. At 1, 2, 4, 6, 15, 28, and 36 weeks after grafting, animals were killed. Human cell-specific markers were used to localize donor cells. Both donor cell types, as revealed by antibodies survived for a substantial time. Their distribution was very different: hRPE cells formed a large clump early on and, with time, spread along the host RPE in a layer one to two cells deep, whereas hSCs formed many smaller clumps, mainly in the subretinal space. Both cells rescued photoreceptors beyond the area of donor cell distribution. The number of surviving cells declined with time. Both hRPE and hSC grafts can survive and rescue photoreceptors for a substantial time after grafting. The number of both donor cell types declined with time, which could be an immune-related problem and/or due to other factors intrinsic to the host RCS retina. The fact that rescue occurred beyond the area of donor cell distribution suggests that diffusible factors are involved, raising the possibility that the two cell types function in a similar manner to rescue photoreceptors.

Xenotransplantation of human neural progenitor cells to the subretinal space of nonimmunosuppressed pigs

DEFF Research Database (Denmark)

Warfvinge, Karin; Schwartz, Philip H; Kiilgaard, Jens Folke

2011-01-01

To investigate the feasibility of transplanting human neural progenitor cells (hNPCs) to the retina of nonimmunosuppressed pigs, cultured hNPCs were injected into the subretinal space of 5 adult pigs after laser burns were applied to promote donor cell integration. Postoperatively, the retinal ve...... that modulation of host immunity is likely necessary for prolonged xenograft survival in this model....

Possible sources of neuroprotection following subretinal silicon chip implantation in RCS rats

Science.gov (United States)

Pardue, Machelle T.; Phillips, Michael J.; Yin, Hang; Fernandes, Alcides; Cheng, Yian; Chow, Alan Y.; Ball, Sherry L.

2005-03-01

Current retinal prosthetics are designed to stimulate existing neural circuits in diseased retinas to create a visual signal. However, implantation of retinal prosthetics may create a neurotrophic environment that also leads to improvements in visual function. Possible sources of increased neuroprotective effects on the retina may arise from electrical activity generated by the prosthetic, mechanical injury due to surgical implantation, and/or presence of a chronic foreign body. This study evaluates these three neuroprotective sources by implanting Royal College of Surgeons (RCS) rats, a model of retinitis pigmentosa, with a subretinal implant at an early stage of photoreceptor degeneration. Treatment groups included rats implanted with active and inactive devices, as well as sham-operated. These groups were compared to unoperated controls. Evaluation of retinal function throughout an 18 week post-implantation period demonstrated transient functional improvements in eyes implanted with an inactive device at 6, 12 and 14 weeks post-implantation. However, the number of photoreceptors located directly over or around the implant or sham incision was significantly increased in eyes implanted with an active or inactive device or sham-operated. These results indicate that in the RCS rat localized neuroprotection of photoreceptors from mechanical injury or a chronic foreign body may provide similar results to subretinal electrical stimulation at the current output evaluated here.

A unique case of phaeohyphomycosis subretinal abscess in a patient with arthropathy and lung pathology.

Science.gov (United States)

Matthews, Bryan J; Partridge, David; Sheard, Richard M; Rennie, Ian G; Mudhar, Hardeep Singh

2013-12-01

A 67-year-old former gold miner with rheumatoid arthritis, treated with steroids and methotrexate, presented to eye casualty with a painful right eye. Examination revealed an anterior uveitis and despite an initial response to topical steroids, the intraocular inflammation worsened with anterior and posterior uveitis development. Re-examination showed a white mass in the peripheral nasal retina initially suspected of being active Toxoplasmosis infection and anti-toxoplasmosis treatment commenced. After improvement and tapering of this treatment, the intraocular inflammation reoccurred. Cytopathological examination of a pars plana vitrectomy obtained vitreous sample that showed a non-diagnostic non-infectious chronic vitritis. The vitreoretinal surgeons elected to do a direct biopsy of the white subretinal mass in the peripheral nasal area. This revealed, quite unexpectedly, an abscess containing pigmented phaeohyphomycosis fungi. This case report documents the multidisciplinary approach that assisted in clinching a final diagnosis and the role of sub-retinal biopsy in this unprecedented scenario.

A unique case of phaeohyphomycosis subretinal abscess in a patient with arthropathy and lung pathology

Directory of Open Access Journals (Sweden)

Bryan J Matthews

2013-01-01

Full Text Available A 67-year-old former gold miner with rheumatoid arthritis, treated with steroids and methotrexate, presented to eye casualty with a painful right eye. Examination revealed an anterior uveitis and despite an initial response to topical steroids, the intraocular inflammation worsened with anterior and posterior uveitis development. Re-examination showed a white mass in the peripheral nasal retina initially suspected of being active Toxoplasmosis infection and anti-toxoplasmosis treatment commenced. After improvement and tapering of this treatment, the intraocular inflammation reoccurred. Cytopathological examination of a pars plana vitrectomy obtained vitreous sample that showed a non-diagnostic non-infectious chronic vitritis. The vitreoretinal surgeons elected to do a direct biopsy of the white subretinal mass in the peripheral nasal area. This revealed, quite unexpectedly, an abscess containing pigmented phaeohyphomycosis fungi. This case report documents the multidisciplinary approach that assisted in clinching a final diagnosis and the role of sub-retinal biopsy in this unprecedented scenario.

In vitro characterization of perfluorocarbon droplets for focused ultrasound therapy

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Schad, Kelly C; Hynynen, Kullervo, E-mail: khynynen@sri.utoronto.c [Imaging Research, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, Toronto, Ontario M4N 3M5 (Canada); Department of Medical Biophysics, University of Toronto (Canada)

2010-09-07

Focused ultrasound therapy can be enhanced with microbubbles by thermal and cavitation effects. However, localization of treatment is difficult as bioeffects can occur outside of the target region. Spatial control of bubbles can be achieved by ultrasound-induced conversion of liquid perfluorocarbon droplets to gas bubbles. This study was undertaken to determine the acoustic parameters for bubble production by droplet conversion and how it depends on the acoustic conditions and droplet physical parameters. Lipid-encapsulated droplets containing dodecafluoropentane were manufactured with sizes ranging from 1.9 to 7.2 {mu}m in diameter and diluted to a concentration of 8 x 10{sup 6} droplets mL{sup -1}. The droplets were sonicated in vitro with a focused ultrasound transducer and varying frequency and exposure under flow conditions through an acoustically transparent vessel. The sonications were 10 ms in duration at frequencies of 0.578, 1.736 and 2.855 MHz. The pressure threshold for droplet conversion was measured with an active transducer operating in pulse-echo mode and simultaneous measurements of broadband acoustic emissions were performed with passive acoustic detection. The results show that droplets cannot be converted at low frequency without broadband emissions occurring. However, the pressure threshold for droplet conversion decreased with increasing frequency, exposure and droplet size. The pressure threshold for broadband emissions was independent of the droplet size and was 2.9, 4.4 and 5.3 MPa for 0.578, 1736 and 2.855 MHz, respectively. In summary, we have demonstrated that droplet conversion is feasible for clinically relevant sized droplets and acoustic exposures.

In vitro characterization of perfluorocarbon droplets for focused ultrasound therapy

International Nuclear Information System (INIS)

Schad, Kelly C; Hynynen, Kullervo

2010-01-01

Focused ultrasound therapy can be enhanced with microbubbles by thermal and cavitation effects. However, localization of treatment is difficult as bioeffects can occur outside of the target region. Spatial control of bubbles can be achieved by ultrasound-induced conversion of liquid perfluorocarbon droplets to gas bubbles. This study was undertaken to determine the acoustic parameters for bubble production by droplet conversion and how it depends on the acoustic conditions and droplet physical parameters. Lipid-encapsulated droplets containing dodecafluoropentane were manufactured with sizes ranging from 1.9 to 7.2 μm in diameter and diluted to a concentration of 8 x 10 6 droplets mL -1 . The droplets were sonicated in vitro with a focused ultrasound transducer and varying frequency and exposure under flow conditions through an acoustically transparent vessel. The sonications were 10 ms in duration at frequencies of 0.578, 1.736 and 2.855 MHz. The pressure threshold for droplet conversion was measured with an active transducer operating in pulse-echo mode and simultaneous measurements of broadband acoustic emissions were performed with passive acoustic detection. The results show that droplets cannot be converted at low frequency without broadband emissions occurring. However, the pressure threshold for droplet conversion decreased with increasing frequency, exposure and droplet size. The pressure threshold for broadband emissions was independent of the droplet size and was 2.9, 4.4 and 5.3 MPa for 0.578, 1736 and 2.855 MHz, respectively. In summary, we have demonstrated that droplet conversion is feasible for clinically relevant sized droplets and acoustic exposures.

In vitro characterization of perfluorocarbon droplets for focused ultrasound therapy

Science.gov (United States)

Schad, Kelly C.; Hynynen, Kullervo

2010-09-01

Focused ultrasound therapy can be enhanced with microbubbles by thermal and cavitation effects. However, localization of treatment is difficult as bioeffects can occur outside of the target region. Spatial control of bubbles can be achieved by ultrasound-induced conversion of liquid perfluorocarbon droplets to gas bubbles. This study was undertaken to determine the acoustic parameters for bubble production by droplet conversion and how it depends on the acoustic conditions and droplet physical parameters. Lipid-encapsulated droplets containing dodecafluoropentane were manufactured with sizes ranging from 1.9 to 7.2 µm in diameter and diluted to a concentration of 8 × 106 droplets mL-1. The droplets were sonicated in vitro with a focused ultrasound transducer and varying frequency and exposure under flow conditions through an acoustically transparent vessel. The sonications were 10 ms in duration at frequencies of 0.578, 1.736 and 2.855 MHz. The pressure threshold for droplet conversion was measured with an active transducer operating in pulse-echo mode and simultaneous measurements of broadband acoustic emissions were performed with passive acoustic detection. The results show that droplets cannot be converted at low frequency without broadband emissions occurring. However, the pressure threshold for droplet conversion decreased with increasing frequency, exposure and droplet size. The pressure threshold for broadband emissions was independent of the droplet size and was 2.9, 4.4 and 5.3 MPa for 0.578, 1736 and 2.855 MHz, respectively. In summary, we have demonstrated that droplet conversion is feasible for clinically relevant sized droplets and acoustic exposures.

Prospective evaluation of subretinal vessel location in polypoidal choroidal vasculopathy (PCV) and response of hemorrhagic and exudative PCV to high-dose antiangiogenic therapy (an American Ophthalmological Society thesis).

Science.gov (United States)

Kokame, Gregg T

2014-07-01

The purpose of this study was to determine the following: (1) Is polypoidal choroidal vasculopathy (PCV) a subretinal neovascular process, rather than a choroidal vascular anomaly? and (2) Is a higher dose of ranibizumab (2.0 mg/0.05 mL) more effective in treating PCV than the current dose (0.5 mg/0.05 mL) approved for treatment of age-related macular degeneration? Retrospective evaluation of PCV in 104 eyes of 86 patients was accomplished with use of indocyanine green angiography plus optical coherence tomography to localize the branching vascular network and the polyps. Nineteen eyes of 19 patients with active leaking and exudation underwent a prospective open-label trial of monthly high-dose intravitreal ranibizumab (2.0 mg/0.05 mL). The primary outcome was prevention of major vision loss (≤15 ETDRS letters). Secondary outcomes included adverse events, improved vision, and changes in subretinal hemorrhage, subretinal fluid, macular edema, and polypoidal complexes at 6 months. The PCV vessels were localized beneath the retinal pigment epithelium (RPE) and above Bruch's membrane in 103 (99%) of 104 eyes. In the high-dose ranibizumab trial at 6 months, none of the patients lost ≥15 letters in visual acuity, and 5 (26%) of 19 gained ≥15 letters. Decreases were noted in subretinal fluid in 14 (82%) of 17 eyes, subretinal hemorrhage in 12 (100%) of 12, RPE detachment in 14 (88%) of 16, macular edema in 11 (92%) of 12, and polyps in 15 (79%) of 19 eyes. PCV vessels are a subtype of subretinal neovascularization located above Bruch's membrane and below RPE. High-dose ranibizumab (2.0 mg/0.05 mL) decreased exudation and hemorrhage and resulted in significant polyp regression, although branching vascular networks persisted.

Subretinal fibrosis and uveitis: a spectral domain OCT study of its evolution and the minimal therapeutic effect of the off-label treatment with ranibizumab.

Science.gov (United States)

Symeonidis, Chrysanthos; Dastiridou, Anna; Konidaris, Vasilis; Brazitikos, Periklis; Androudi, Sofia

2014-12-01

The subretinal fibrosis and uveitis (SFU) syndrome is a rare multifocal posterior uveitis characterized by progressive subretinal fibrosis and significant visual loss. Slit-lamp examination, dilated fundoscopy, fluorescein angiography, Spectral Domain-Optical Coherence Tomography (SD-OCT) and laboratory testing were employed. A 52-year-old male presented with bilateral (best-corrected visual acuity: 2/10) visual loss. Clinical examination revealed bilateral anterior uveitis with posterior synechiae and posterior uveitis. Medical workup revealed no pathologic findings. Treatment included 1 gr intravenous prednisone followed by oral prednisone, immunosuppresive therapy and three ranibizumab injections in the right eye with no improvement. One year later, there was significant subretinal fibrosis. In the second year follow-up, the picture was slightly worse, with persisting bilateral macular edema and fibrosis. This is the first SFU syndrome report monitored with SD-OCT. This novel imaging modality can localize the lesion level, guide the therapeutic approach and may prove helpful in assessing disease prognosis.

ASSOCIATION BETWEEN VISUAL FUNCTION AND SUBRETINAL DRUSENOID DEPOSITS IN NORMAL AND EARLY AGE-RELATED MACULAR DEGENERATION EYES.

Science.gov (United States)

Neely, David; Zarubina, Anna V; Clark, Mark E; Huisingh, Carrie E; Jackson, Gregory R; Zhang, Yuhua; McGwin, Gerald; Curcio, Christine A; Owsley, Cynthia

2017-07-01

To examine the association between subretinal drusenoid deposits (SDDs) identified by multimodal retinal imaging and visual function in older eyes with normal macular health or in the earliest phases of age-related macular degeneration (AMD). Age-related macular degeneration status for each eye was defined according to the Age-Related Eye Disease Study (AREDS) 9-step classification system (normal = Step 1, early AMD = Steps 2-4) based on color fundus photographs. Visual functions measured were best-corrected photopic visual acuity, contrast and light sensitivity, mesopic visual acuity, low-luminance deficit, and rod-mediated dark adaptation. Subretinal drusenoid deposits were identified through multimodal imaging (color fundus photographs, infrared reflectance and fundus autofluorescence images, and spectral domain optical coherence tomography). The sample included 1,202 eyes (958 eyes with normal health and 244 eyes with early AMD). In normal eyes, SDDs were not associated with any visual function evaluated. In eyes with early AMD, dark adaptation was markedly delayed in eyes with SDDs versus no SDD (a 4-minute delay on average), P = 0.0213. However, this association diminished after age adjustment, P = 0.2645. Other visual functions in early AMD eyes were not associated with SDDs. In a study specifically focused on eyes in normal macular health and in the earliest phases of AMD, early AMD eyes with SDDs have slower dark adaptation, largely attributable to the older ages of eyes with SDD; they did not exhibit deficits in other visual functions. Subretinal drusenoid deposits in older eyes in normal macular health are not associated with any visual functions evaluated.

The potential role of perfluorocarbon emulsions in decompression illness.

Science.gov (United States)

Spiess, Bruce D

2010-03-01

Decompression illness (DCI) is an occasional occurrence in sport, professional, and military diving as well as a potential catastrophe in high-altitude flight, space exploration, mining, and caisson bridge construction. DCI theoretically could be a success-limiting problem in escape from a disabled submarine (DISSUB). Perfluorocarbon emulsions (PFCs) have previously been investigated as 'blood substitutes' with one approved by the United States Food and Drug Administration for the treatment of myocardial ischaemia. PFCs possess enhanced (as compared to plasma) respiratory gas solubility characteristics, including oxygen, nitrogen and carbon dioxide. This review examines approximately 30 years of research regarding the utilization of PFCs in gas embolism as well as experimental DCI. To date, no humans have been treated with PFCs for DCI.

Clinical applications of perfluorocarbon nanoparticles for molecular imaging and targeted therapeutics.

Science.gov (United States)

Tran, Trung D; Caruthers, Shelton D; Hughes, Michael; Marsh, John N; Cyrus, Tillmann; Winter, Patrick M; Neubauer, Anne M; Wickline, Samuel A; Lanza, Gregory M

2007-01-01

Molecular imaging is a novel tool that has allowed non-invasive diagnostic imaging to transition from gross anatomical description to identification of specific tissue epitopes and observation of biological processes at the cellular level. This technique has been confined to the field of nuclear imaging; however, recent advances in nanotechnology have extended this research to include ultrasound (US) and magnetic resonance (MR) imaging. The exploitation of nanotechnology for MR and US molecular imaging has generated several candidate contrast agents. One multimodality platform, targeted perfluorocarbon (PFC) nanoparticles, is useful for noninvasive detection with US and MR, targeted drug delivery, and quantification.

Liquid ventilation.

Science.gov (United States)

Sarkar, Suman; Paswan, Anil; Prakas, S

2014-01-01

Human have lungs to breathe air and they have no gills to breath liquids like fish. When the surface tension at the air-liquid interface of the lung increases as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen as the inert carrier of oxygen and carbon dioxide offers a number of advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. It is well-known that respiratory diseases are one of the most common causes of morbidity and mortality in intensive care unit. During the past few years several new modalities of treatment have been introduced. One of them and probably the most fascinating, is of LV. Partial LV, on which much of the existing research has concentrated, requires partial filling of lungs with perfluorocarbons (PFC's) and ventilation with gas tidal volumes using conventional mechanical ventilators. Various physico-chemical properties of PFC's make them the ideal media. It results in a dramatic improvement in lung compliance and oxygenation and decline in mean airway pressure and oxygen requirements. No long-term side-effect reported.

Commercial applications of perfluorocarbon tracer (PFT) technology

International Nuclear Information System (INIS)

Dietz, R.N.

1991-06-01

Tracer technology can be successfully applied to many leak-checking and monitoring evaluations of operating systems (e.g., building HVACs), manufacturing processes and products (e.g., air conditioners), and subsurface components and systems (e.g., underground storage tanks). Perfluorocarbon tracer (PFT) technology is the most sensitive of all tracer technologies because the ambient background levels of the five (5) routinely-used PFTs are in the range of parts per 10 15 parts of air (i.e., parts per quadrillion-ppq) and this technology's instrumentation can measure down to those levels. The effectiveness of this technology is achieved both in terms of cost (very little PFT need to be used) and detectability; for example, very small leaks can be rapidly detected. The PFT compounds, which are environmentally and biologically safe to use, are commercially available as are the sampling and analysis instrumentation. This presentation concerns (1) the steps being taken to commercialize this technology, (2) new applications of processes currently under study, and (3) applications in areas of use that will be particularly beneficial to the environment. 21 refs., 2 figs., 2 tabs

Visual loss related to macular subretinal fluid and cystoid macular edema in HIV-related optic neuropathy

DEFF Research Database (Denmark)

Gautier, David; Rabier, Valérie; Jallet, Ghislaine

2012-01-01

Optic nerve involvement may occur in various infectious diseases, but is rarely reported after infection by the human immunodeficiency virus (HIV). We report the atypical case of a 38-year-old patient in whom the presenting features of HIV infection were due to a bilateral optic neuropathy associ...... associated with macular subretinal fluid and cystoid macular edema, which responded well to antiretroviral therapy....

Endogenous Cryptococcus neoformans endophthalmitis with subretinal abscess in a HIV-infected man.

Science.gov (United States)

Joseph, Joveeta; Sharma, Savitri; Narayanan, Raja

2018-07-01

To report a rare case of Cryptococcus neoformans endogenous endophthalmitis with subretinal abscess in a 36-year-old HIV-positive man, referred with progressive blurred vision in his right eye for the last 6 months. Vitreous biopsy followed by intravitreal ganciclovir did not result in significant improvement. Microbiology revealed the presence of C. neoformans, and intravitreal amphotericin B was then administered. The patient was treated aggressively with systemic and intravitreal antifungals but had a poor visual and anatomical outcome. A high degree of clinical suspicion combined with microbiological evaluation helped to arrive at an appropriate diagnosis.

HL-217, a new topical anti-angiogenic agent, inhibits retinal vascular leakage and pathogenic subretinal neovascularization in Vldlr−/− mice

International Nuclear Information System (INIS)

Kim, Junghyun; Kim, Chan-Sik; Jo, Kyuhyung; Cho, Yun-Seok; Kim, Hyun-Gyu; Lee, Geun-Hyeog; Lee, Yun Mi; Sohn, Eunjin; Kim, Jin Sook

2015-01-01

Highlights: • HL-217 is a new synthetic topical anti-angiogenic agent. • HL-217 attenuated subretinal neovascularization in Vldlr −/− mice. • HL-217 blocked the binding of PDGF-BB to PDGFRβ. - Abstract: HL-217 is a new synthetic angiogenesis inhibitor. Platelet derived growth factor (PDGF) is a vasoactive factor and has been implicated in proliferative retinopathies. In this study, we examined the mechanism of action and efficacy of topical application of HL-217 on subretinal neovascularization in very low-density lipoprotein receptor knockout (Vldlr −/− ) mice. In three-week-old male Vldlr −/− mice, HL-217 (1.5 or 3 mg/ml) was administered twice per day for 4 weeks by topical eye drop instillation. Neovascular areas were then measured. We used a protein array to evaluate the expression levels of angiogenic factors. The inhibitory effect of HL-217 on the PDGF-BB/PDGFRβ interaction was evaluated in vitro. The neovascular area in the Vldlr −/− mice was significantly reduced by HL-217. Additionally, HL-217 decreased the expression levels of PDGF-BB protein and VEGF mRNA. Moreover, HL-217 dose-dependently inhibited the PDGF-BB/PDGFRβ interaction (IC 50 = 38.9 ± 0.7 μM). These results suggest that HL-217 is a potent inhibitor of PDGF-BB. HL-217, when applied topically, is an effective inhibitor of subretinal neovascularization due to its ability to inhibit the pro-angiogenic effects of PDGF-BB

Enhanced oxygen delivery induced by perfluorocarbon emulsions in capillary tube oxygenators.

Science.gov (United States)

Vaslef, S N; Goldstick, T K

1994-01-01

Previous studies showed that a new generation of perfluorocarbon (PFC) emulsions increased tissue PO2 in the cat retina to a degree that could not be explained by the small increase in arterial O2 content seen after the infusion of low doses of 1 g PFC/kg body weight. It seems that increased O2 delivery at the tissue level after PFC infusion is caused by a local effect in the microcirculation. The authors studies this effect in vitro at steady state in a closed loop circuit, consisting of one of two types of capillary tube oxygenators, deoxygenator(s), a reservoir bag filled with anticoagulated bovine blood or saline (control), and a roller pump, to see if the addition of PFC would have an effect on the PO2 difference (delta PO2) across the capillary tube membrane oxygenator at a blood flow rate of 3 l/min. Perfluorocarbon was added in three incremental doses, each giving about 0.7 vol% of PFC. The delta PO2 across the oxygenator was measured before and after each dose. The mean percent increases in delta PO2 in blood for two types of oxygenators were 19.2 +/- 8% (mean +/- SD, n = 6, P = 0.002) and 9.9 +/- 4% (n = 3, P = 0.05), respectively, whereas the mean percent change in delta PO2 in saline was -4.9 +/- 2% (n = 2, P = 0.2). Inlet PO2s to the oxygenator were only minimally increased. The authors conclude that O2 delivery was significantly enhanced after injection of PFC in blood in this capillary tube model. A near wall excess of PFC particles may account for the augmentation of O2 diffusion in this model.

New mechanisms for non-porative ultrasound stimulation of cargo delivery to cell cytosol with targeted perfluorocarbon nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Soman, N R; Marsh, J N; Lanza, G M; Wickline, S A [Washington University School of Medicine, Consortium for Translational Research in Advanced Imaging and Nanomedicine, CTRAIN, Campus Box 8215, St Louis, MO 63110 (United States)], E-mail: saw@wuphys.wustl.edu

2008-05-07

The cell membrane constitutes a major barrier for non-endocytotic intracellular delivery of therapeutic molecules from drug delivery vehicles. Existing approaches to breaching the cell membrane include cavitational ultrasound (with microbubbles), electroporation and cell-penetrating peptides. We report the use of diagnostic ultrasound for intracellular delivery of therapeutic bulky cargo with the use of molecularly targeted liquid perfluorocarbon (PFC) nanoparticles. To demonstrate the concept, we used a lipid with a surrogate polar head group, nanogold-DPPE, incorporated into the nanoparticle lipid monolayer. Melanoma cells were incubated with nanogold particles and this was followed by insonication with continuous wave ultrasound (2.25 MHz, 5 min, 0.6 MPa). Cells not exposed to ultrasound showed gold particles partitioned only in the outer bilayer of the cell membrane with no evidence of the intracellular transit of nanogold. However, the cells exposed to ultrasound exhibited numerous nanogold-DPPE components inside the cell that appeared polarized inside intracellular vesicles demonstrating cellular uptake and trafficking. Further, ultrasound-exposed cells manifested no incorporation of calcein or the release of lactate dehydrogenase. These observations are consistent with a mechanism that suggests that ultrasound is capable of stimulating the intracellular delivery of therapeutic molecules via non-porative mechanisms. Therefore, non-cavitational adjunctive ultrasound offers a novel paradigm in intracellular cargo delivery from PFC nanoparticles.

New mechanisms for non-porative ultrasound stimulation of cargo delivery to cell cytosol with targeted perfluorocarbon nanoparticles

International Nuclear Information System (INIS)

Soman, N R; Marsh, J N; Lanza, G M; Wickline, S A

2008-01-01

The cell membrane constitutes a major barrier for non-endocytotic intracellular delivery of therapeutic molecules from drug delivery vehicles. Existing approaches to breaching the cell membrane include cavitational ultrasound (with microbubbles), electroporation and cell-penetrating peptides. We report the use of diagnostic ultrasound for intracellular delivery of therapeutic bulky cargo with the use of molecularly targeted liquid perfluorocarbon (PFC) nanoparticles. To demonstrate the concept, we used a lipid with a surrogate polar head group, nanogold-DPPE, incorporated into the nanoparticle lipid monolayer. Melanoma cells were incubated with nanogold particles and this was followed by insonication with continuous wave ultrasound (2.25 MHz, 5 min, 0.6 MPa). Cells not exposed to ultrasound showed gold particles partitioned only in the outer bilayer of the cell membrane with no evidence of the intracellular transit of nanogold. However, the cells exposed to ultrasound exhibited numerous nanogold-DPPE components inside the cell that appeared polarized inside intracellular vesicles demonstrating cellular uptake and trafficking. Further, ultrasound-exposed cells manifested no incorporation of calcein or the release of lactate dehydrogenase. These observations are consistent with a mechanism that suggests that ultrasound is capable of stimulating the intracellular delivery of therapeutic molecules via non-porative mechanisms. Therefore, non-cavitational adjunctive ultrasound offers a novel paradigm in intracellular cargo delivery from PFC nanoparticles

New mechanisms for non-porative ultrasound stimulation of cargo delivery to cell cytosol with targeted perfluorocarbon nanoparticles

Science.gov (United States)

Soman, N. R.; Marsh, J. N.; Lanza, G. M.; Wickline, S. A.

2008-05-01

The cell membrane constitutes a major barrier for non-endocytotic intracellular delivery of therapeutic molecules from drug delivery vehicles. Existing approaches to breaching the cell membrane include cavitational ultrasound (with microbubbles), electroporation and cell-penetrating peptides. We report the use of diagnostic ultrasound for intracellular delivery of therapeutic bulky cargo with the use of molecularly targeted liquid perfluorocarbon (PFC) nanoparticles. To demonstrate the concept, we used a lipid with a surrogate polar head group, nanogold-DPPE, incorporated into the nanoparticle lipid monolayer. Melanoma cells were incubated with nanogold particles and this was followed by insonication with continuous wave ultrasound (2.25 MHz, 5 min, 0.6 MPa). Cells not exposed to ultrasound showed gold particles partitioned only in the outer bilayer of the cell membrane with no evidence of the intracellular transit of nanogold. However, the cells exposed to ultrasound exhibited numerous nanogold-DPPE components inside the cell that appeared polarized inside intracellular vesicles demonstrating cellular uptake and trafficking. Further, ultrasound-exposed cells manifested no incorporation of calcein or the release of lactate dehydrogenase. These observations are consistent with a mechanism that suggests that ultrasound is capable of stimulating the intracellular delivery of therapeutic molecules via non-porative mechanisms. Therefore, non-cavitational adjunctive ultrasound offers a novel paradigm in intracellular cargo delivery from PFC nanoparticles.

Correlation of In Vivo and In Vitro Methods in Measuring Choroidal Vascularization Volumes Using a Subretinal Injection Induced Choroidal Neovascularization Model

Directory of Open Access Journals (Sweden)

Chuang Nie

2015-01-01

Full Text Available Background: In vivo quantification of choroidal neovascularization (CNV based on noninvasive optical coherence tomography (OCT examination and in vitro choroidal flatmount immunohistochemistry stained of CNV currently were used to evaluate the process and severity of age-related macular degeneration (AMD both in human and animal studies. This study aimed to investigate the correlation between these two methods in murine CNV models induced by subretinal injection. Methods: CNV was developed in 20 C57BL6/j mice by subretinal injection of adeno-associated viral delivery of a short hairpin RNA targeting sFLT-1 (AAV.shRNA.sFLT-1, as reported previously. After 4 weeks, CNV was imaged by OCT and fluorescence angiography. The scaling factors for each dimension, x, y, and z (μm/pixel were recorded, and the corneal curvature standard was adjusted from human (7.7 to mice (1.4. The volume of each OCT image stack was calculated and then normalized by multiplying the number of voxels by the scaling factors for each dimension in Seg3D software (University of Utah Scientific Computing and Imaging Institute, available at http://www.sci.utah.edu/cibc-software/seg3d.html. Eighteen mice were prepared for choroidal flatmounts and stained by CD31. The CNV volumes were calculated using scanning laser confocal microscopy after immunohistochemistry staining. Two mice were stained by Hematoxylin and Eosin for observing the CNV morphology. Results: The CNV volume calculated using OCT was, on average, 2.6 times larger than the volume calculated using the laser confocal microscopy. The correlation statistical analysis showed OCT measuring of CNV correlated significantly with the in vitro method (R 2 =0.448, P = 0.001, n = 18. The correlation coefficient for CNV quantification using OCT and confocal microscopy was 0.693 (n = 18, P = 0.001. Conclusions: There is a fair linear correlation on CNV volumes between in vivo and in vitro methods in CNV models induced by subretinal

HL-217, a new topical anti-angiogenic agent, inhibits retinal vascular leakage and pathogenic subretinal neovascularization in Vldlr{sup −/−} mice

Energy Technology Data Exchange (ETDEWEB)

Kim, Junghyun; Kim, Chan-Sik; Jo, Kyuhyung [Korean Medicine Based Herbal Drug Development Group, Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon (Korea, Republic of); Cho, Yun-Seok; Kim, Hyun-Gyu; Lee, Geun-Hyeog [Research and Development Center, Hanlim Pharm. Co. Ltd., 1656-10, Seocho-dong, Seocho-gu, Seoul (Korea, Republic of); Lee, Yun Mi; Sohn, Eunjin [Korean Medicine Based Herbal Drug Development Group, Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon (Korea, Republic of); Kim, Jin Sook, E-mail: jskim@kiom.re.kr [Korean Medicine Based Herbal Drug Development Group, Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon (Korea, Republic of)

2015-01-02

Highlights: • HL-217 is a new synthetic topical anti-angiogenic agent. • HL-217 attenuated subretinal neovascularization in Vldlr{sup −/−} mice. • HL-217 blocked the binding of PDGF-BB to PDGFRβ. - Abstract: HL-217 is a new synthetic angiogenesis inhibitor. Platelet derived growth factor (PDGF) is a vasoactive factor and has been implicated in proliferative retinopathies. In this study, we examined the mechanism of action and efficacy of topical application of HL-217 on subretinal neovascularization in very low-density lipoprotein receptor knockout (Vldlr{sup −/−}) mice. In three-week-old male Vldlr{sup −/−} mice, HL-217 (1.5 or 3 mg/ml) was administered twice per day for 4 weeks by topical eye drop instillation. Neovascular areas were then measured. We used a protein array to evaluate the expression levels of angiogenic factors. The inhibitory effect of HL-217 on the PDGF-BB/PDGFRβ interaction was evaluated in vitro. The neovascular area in the Vldlr{sup −/−} mice was significantly reduced by HL-217. Additionally, HL-217 decreased the expression levels of PDGF-BB protein and VEGF mRNA. Moreover, HL-217 dose-dependently inhibited the PDGF-BB/PDGFRβ interaction (IC{sub 50} = 38.9 ± 0.7 μM). These results suggest that HL-217 is a potent inhibitor of PDGF-BB. HL-217, when applied topically, is an effective inhibitor of subretinal neovascularization due to its ability to inhibit the pro-angiogenic effects of PDGF-BB.

Laser cutting of silicon with the liquid jet guided laser using a chlorine-containing jet media

Energy Technology Data Exchange (ETDEWEB)

Hopman, Sybille; Mayer, Kuno; Fell, Andreas; Mesec, Matthias; Granek, Filip [Fraunhofer Institute for Solar Energy Systems ISE, Freiburg (Germany)

2011-03-15

In this paper results for liquid media are presented, which are used the first time as liquid jet for cutting of silicon with laser chemical processing (LCP). The liquids contain a perfluoro-carbon compound as solvent and elemental chlorine as etching agent for silicon. Experiments were performed to investigate its influence on groove form and maximum achieved groove depth. It is shown that with the addition of low-concentration chlorine, the groove depth can already be significantly increased. The groove shape could be changed from a V-profile to a U-profile. Furthermore, an about four times greater groove depth was achieved by applying a saturated chlorine solution compared to groove depths without using chlorine. Finally, a theory is given and discussed to describe the phenomena observed. (orig.)

Optimization of pillar electrodes in subretinal prosthesis for enhanced proximity to target neurons

Science.gov (United States)

Flores, Thomas; Lei, Xin; Huang, Tiffany; Lorach, Henri; Dalal, Roopa; Galambos, Ludwig; Kamins, Theodore; Mathieson, Keith; Palanker, Daniel

2018-06-01

Objective. High-resolution prosthetic vision requires dense stimulating arrays with small electrodes. However, such miniaturization reduces electrode capacitance and penetration of electric field into tissue. We evaluate potential solutions to these problems with subretinal implants based on utilization of pillar electrodes. Approach. To study integration of three-dimensional (3D) implants with retinal tissue, we fabricated arrays with varying pillar diameter, pitch, and height, and implanted beneath the degenerate retina in rats (Royal College of Surgeons, RCS). Tissue integration was evaluated six weeks post-op using histology and whole-mount confocal fluorescence imaging. The electric field generated by various electrode configurations was calculated in COMSOL, and stimulation thresholds assessed using a model of network-mediated retinal response. Main results. Retinal tissue migrated into the space between pillars with no visible gliosis in 90% of implanted arrays. Pillars with 10 μm height reached the middle of the inner nuclear layer (INL), while 22 μm pillars reached the upper portion of the INL. Electroplated pillars with dome-shaped caps increase the active electrode surface area. Selective deposition of sputtered iridium oxide onto the cap ensures localization of the current injection to the pillar top, obviating the need to insulate the pillar sidewall. According to computational model, pillars having a cathodic return electrode above the INL and active anodic ring electrode at the surface of the implant would enable six times lower stimulation threshold, compared to planar arrays with circumferential return, but suffer from greater cross-talk between the neighboring pixels. Significance. 3D electrodes in subretinal prostheses help reduce electrode-tissue separation and decrease stimulation thresholds to enable smaller pixels, and thereby improve visual acuity of prosthetic vision.

An update: improvements in imaging perfluorocarbon-mounted plant leaves with implications for studies of plant pathology, physiology, development and cell biology.

Directory of Open Access Journals (Sweden)

George R Littlejohn

2014-04-01

Full Text Available Plant leaves are optically complex, which makes them difficult to image by light microscopy. Careful sample preparation is therefore required to enable researchers to maximise the information gained from advances in fluorescent protein labelling, cell dyes and innovations in microscope technologies and techniques. We have previously shown that mounting leaves in the non-toxic, non-fluorescent perfluorocarbon (PFC, perfluorodecalin (PFD enhances the optical properties of the leaf with minimal impact on physiology. Here, we assess the use of the perfluorocarbons PFD, and perfluoroperhydrophenanthrene (PP11 for in vivo plant leaf imaging using 4 advanced modes of microscopy: laser scanning confocal microscopy (LSCM, Two-photon fluorescence (TPF microscopy, second harmonic generation (SHG microscopy and stimulated Raman scattering (SRS microscopy. For every mode of imaging tested, we observed an improved signal when leaves were mounted in PFD or in PP11, compared to mounting the samples in water. Using an image analysis technique based on autocorrelation to quantitatively assess LSCM image deterioration with depth, we show that PP11 outperformed PFD as a mounting medium by enabling the acquisition of clearer images deeper into the tissue. In addition, we show that SRS microscopy can be used to image perfluorocarbons directly in the mesophyll and thereby easily delimit the negative space within a leaf, which may have important implications for studies of leaf development. Direct comparison of on and off resonance SRS micrographs show that PFCs do not to form intracellular aggregates in live plants. We conclude that the application of PFCs as mounting media substantially increases advanced microscopy image quality of living mesophyll and leaf vascular bundle cells.

Characterization of a Polymer-Based, Fully Organic Prosthesis for Implantation into the Subretinal Space of the Rat.

Science.gov (United States)

Antognazza, Maria Rosa; Di Paolo, Mattia; Ghezzi, Diego; Mete, Maurizio; Di Marco, Stefano; Maya-Vetencourt, José Fernando; Maccarone, Rita; Desii, Andrea; Di Fonzo, Fabio; Bramini, Mattia; Russo, Angela; Laudato, Lucia; Donelli, Ilaria; Cilli, Michele; Freddi, Giuliano; Pertile, Grazia; Lanzani, Guglielmo; Bisti, Silvia; Benfenati, Fabio

2016-09-01

Replacement strategies arise as promising approaches in case of inherited retinal dystrophies leading to blindness. A fully organic retinal prosthesis made of conjugated polymers layered onto a silk fibroin substrate is engineered. First, the biophysical and surface properties are characterized; then, the long-term biocompatibility is assessed after implantation of the organic device in the subretinal space of 3-months-old rats for a period of five months. The results indicate a good stability of the subretinal implants over time, with preservation of the physical properties of the polymeric layer and a tight contact with the outer retina. Immunoinflammatory markers detect only a modest tissue reaction to the surgical insult and the foreign body that peaks shortly after surgery and progressively decreases with time to normal levels at five months after implantation. Importantly, the integrity of the polymeric layer in direct contact with the retinal tissue is preserved after five months of implantation. The recovery of the foreign-body tissue reaction is also associated with a normal b-wave in the electroretinographic response. The results demonstrate that the device implanted in nondystrophic eyes is well tolerated, highly biocompatible, and suitable as retinal prosthesis in case of photoreceptor degeneration. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and experimental basis of local subretinal technique of xenogenic’s injection stem cells labelled by magnetic perticles

Directory of Open Access Journals (Sweden)

Yu. A. Belyy

2014-10-01

Full Text Available Purpose: is to develop a technique for local subretinal injection of xenogeneic stem cells labeled with magnetic particles and to prove experimentally its effectiveness.Material and methods: We used a line of stem cells HEK-293 GFP,labeled with magnetic particles. The study was made on 84 eyes of 42 chinchilla rabbits 6 months of age, the weight were from 2.5 to 3.5 kg. All right eyes were experimental (42 eyes and all left eyes (42 eyes were the control group. In the experimental group we used original complex of polymer elastic magnetic implant (PEMI with laser probe and fixed it to the sclera, then we made a median vitrectomy and injected HEK-293 GFP under the retina using a specially designed dispenser. In the control group PEMI was not fixed. We examined animals using biomicroscopy, ophthalmoscopy, ultrasound scanning, optical coherence tomography  OCT, computer tomography (CT, morphological study (cryohistological sections in 1, 3, 5, 7, 14 day and 1 month after surgery.Results: According the results of biomicroscopy in observation periods up to 3 days the vascular injection was visualized in the area operation. According the results of ophthalmoscopy and ultrasound scanning in 1 day the local retinal detachment was visualized in the area of local injection of the stem cells, which was not visualized in terms of further observations. CT helped us to confirm the local place of PEMI fixation. The morphological study results showed that cells were located in the subretinal space up to 14 days in the experimental group, and only up 3 days in the control group.Conclusion: The suggested surgical technique enables to control the injection of cells into the subretinal space, reduces the risk of tissue damage and exit cells in the vitreous space. The suggested methodology allows the fixing of the cellular material in the local place of the injection and enables to predict cells`s movement.

Perfluorocarbon in Delayed Recompression with a Mixed Gender Swine Model of Decompression Sickness.

Science.gov (United States)

Cronin, William A; Hall, Aaron A; Auker, Charles R; Mahon, Richard T

2018-01-01

Perfluorocarbons (PFC) are fluorinated hydrocarbons that dissolve gases to a much greater degree than plasma and hold promise in treating decompression sickness (DCS). The efficacy of PFC in a mixed gender model of DCS and safety in recompression therapy has not been previously explored. Swine (25 kg; N = 104; 51 male and 53 female) were randomized into normal saline solution (NSS) or PFC emulsion treatment groups and subjected to compression on air in a hyperbaric chamber at 200 fsw for 31 min. Then the animals were decompressed and observed for signs of DCS. Afterwards, they were treated with oxygen and either PFC (4 cc · kg-1) or NSS (4 cc · kg-1). Surviving animals were observed for 4 h, at which time they underwent recompression therapy using a standard Navy Treatment Table 6. After 24 h the animals were assessed and then euthanized. Survival rates were not significantly different between NSS (74.04%) and PFC (66.67%) treatment groups. All swine that received recompression treatment survived to the end of the study and no seizures were observed in either PFC or NSS animals. Within the saline treated swine group there were no significant differences in DCS survival between male (75.00%, N = 24) and female (73.08%, N = 26) swine. Within the PFC treated swine, survival of females (51.85%, N = 27) was significantly lower than males (81.48%, N = 27). In this large animal mixed gender efficacy study in DCS, PFC did not improve mortality or spinal cord injury, but appears safe during recompressive therapy. Gender differences in DCS treatment with PFC will need further study.Cronin WA, Hall AA, Auker CR, Mahon RT. Perfluorocarbon in delayed recompression with a mixed gender swine model of decompression sickness. Aerosp Med Hum Perform. 2018; 89(1):14-18.

Perfluorocarbon-perfused 23 gauge three-dimensional vitrectomy for complicated diabetic tractional retinal detachment

Science.gov (United States)

Velez-Montoya, Raul; Guerrero-Naranjo, Jose Luis; Garcia-Aguirre, Gerardo; Morales-Cantón, Virgilio; Fromow-Guerra, Jans; Quiroz-Mercado, Hugo

2011-01-01

Background Perfluorocarbon liquid (PCL)-perfused vitrectomy has been shown in previous studies to be feasible, safe, and to have advantages in managing complicated cases of tractional retinal detachment. The present study had the objectives of describing the anatomical results and measuring surgical time and PCL consumption when combining PCL-perfused techniques with modern vitrectomy equipment. Methods A prospective, interventional consecutive case series was investigated. We enrolled patients with diabetic tractional retinal detachment, complicated by proliferative vitreoretinopathy and poor vision. A 23 gauge PCL-perfused vitrectomy was done with three-dimensional settings. During the procedure, we assessed the degree of surgical bleeding, visualization quality, and difficulty of membrane dissections. Visual acuity, intraocular pressure, and anatomical success were assessed at one and 3 months of follow-up. Results Twelve patients were enrolled in this study. There were no statistical significant changes in intraocular pressure and visual acuity throughout the follow-up period. Surgery was performed in a hemorrhage-free environment in almost all cases, with good visualization and low technical difficulty. The mean complete surgical time was 94.92 ± 25.03 minutes. The mean effective vitrectomy time was 22.50 ± 19.04 minutes and the mean PCL consumption was 25.08 ± 9.76 mL, with a speed of 1.11 mL/minute. Anatomical success was 67% at 3 months. Conclusion Although the technique proved to have some advantages in managing complicated cases of diabetic tractional retinal detachment, there was a high consumption of PCL. A redesign of the entire system is needed in order to decrease the amount of PCL needed for the technique. PMID:22267907

COMPLETE SUBRETINAL FLUID DRAINAGE IS NOT NECESSARY DURING VITRECTOMY SURGERY FOR MACULA-OFF RHEGMATOGENOUS RETINAL DETACHMENT WITH PERIPHERAL BREAKS: A Prospective, Nonrandomized Comparative Interventional Study.

Science.gov (United States)

Chen, Xiao; Zhang, Yong; Yan, Ying; Hong, Ling; Zhu, Li; Deng, Jun; Din, Qin; Huang, Zhijian; Zhou, Hezhen

2017-03-01

To compare clinical outcomes in eyes with macula-off rhegmatogenous retinal detachments managed by surgical protocols, the result in either complete (CSFD) or partial subretinal fluid drainage (PSFD). Fifty-four eyes with macula-off rhegmatogenous retinal detachments with peripheral retinal breaks of 54 patients were assigned prospectively to one of the two surgical designs (PSFD or CSFD, 2:1) in a sequence. Patients were treated with 25-gauge plus vitrectomy, either CSFD (n = 18) or PSFD (n = 36), and 14% C3F8 was used for intraocular tamponade. Anatomical and visual outcomes as well as intraoperative and postoperative complications of the two groups were compared. The single-operation success rates were 16/18 (88.9%) and 33/36 (91.6%), respectively, for the CSFD and the PSFD groups (P = 1.00). The mean BCVA improvement (Early Treatment Diabetic Retinopathy Study letters) at the 6-month postoperative was not significantly different between the two groups (26.50 ± 15.43 in CSFD group vs. 22.64 ± 15.43 in PSFD group, P = 0.43). Partial subretinal fluid drainage procedure during vitrectomy for the repair of macula-off rhegmatogenous retinal detachments revealed comparable results with CSFD in terms of anatomical and visual outcomes. Complete subretinal fluid drainage during vitrectomy seems to be unnecessary for all RRD reattachment surgical procedures.

CityFlux perfluorocarbon tracer experiments

Science.gov (United States)

Petersson, F. K.; Martin, D.; White, I. R.; Henshaw, S. J.; Nickless, G.; Longley, I.; Percival, C. J.; Gallagher, M.; Shallcross, D. E.

2010-07-01

In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m. The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site. Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail. The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this. The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

Human RPE Stem Cells Grown into Polarized RPE Monolayers on a Polyester Matrix Are Maintained after Grafting into Rabbit Subretinal Space

Directory of Open Access Journals (Sweden)

Boris V. Stanzel

2014-01-01

Full Text Available Transplantation of the retinal pigment epithelium (RPE is being developed as a cell-replacement therapy for age-related macular degeneration. Human embryonic stem cell (hESC and induced pluripotent stem cell (iPSC-derived RPE are currently translating toward clinic. We introduce the adult human RPE stem cell (hRPESC as an alternative RPE source. Polarized monolayers of adult hRPESC-derived RPE grown on polyester (PET membranes had near-native characteristics. Trephined pieces of RPE monolayers on PET were transplanted subretinally in the rabbit, a large-eyed animal model. After 4 days, retinal edema was observed above the implant, detected by spectral domain optical coherence tomography (SD-OCT and fundoscopy. At 1 week, retinal atrophy overlying the fetal or adult transplant was observed, remaining stable thereafter. Histology obtained 4 weeks after implantation confirmed a continuous polarized human RPE monolayer on PET. Taken together, the xeno-RPE survived with retained characteristics in the subretinal space. These experiments support that adult hRPESC-derived RPE are a potential source for transplantation therapies.

Velocity of sound measurements in gaseous per-fluorocarbons and their custom mixtures

CERN Document Server

Vacek, V; Lindsay, S

2000-01-01

An inexpensive sonar instrument was prepared for measurements of sound velocity in two fluorocarbon vapors; per-fluoro-n-propane (C3F8), per-fluoro-n-butane (C4F10), and their custom mixtures. The apparatus, measurement principle and instrument software are described. All sound velocity measurements in per-fluorocarbons were made in the low pressure range between 0.01 and 0.4 MPa, and at temperatures between 253 and 303 K. The purity of the C3F8 and C4F10 samples was checked using gas chromatography. Uncertainties in the speed of sound measurements were better than ± 0.1 %. Comparisons were made with theoretical predictions of sound velocity for the two individual components. The instrument was then used for concentration monitoring of custom C3F8/C4F10 mixtures.

High Concentration of Zinc in Sub-retinal Pigment Epithelial Deposits

Energy Technology Data Exchange (ETDEWEB)

Lengyel,I.; Flinn, J.; Peto, T.; Linkous, D.; Cano, K.; Bird, A.; Lanzirotti, A.; Frederickson, C.; van Kuijk, F.

2007-01-01

One of the hallmarks of age-related macular degeneration (AMD), the leading cause of blindness in the elderly in Western societies, is the accumulation of sub-retinal pigment epithelial deposits (sub-RPE deposits), including drusen and basal laminar deposits, in Bruch's membrane (BM). The nature and the underlying mechanisms of this deposit formation are not fully understood. Because we know that zinc contributes to deposit formation in neurodegenerative diseases, we tested the hypothesis that zinc might be involved in deposit formation in AMD. Using zinc specific fluorescent probes and microprobe synchrotron X-ray fluorescence we showed that sub-RPE deposits in post-mortem human tissues contain unexpectedly high concentrations of zinc, including abundant bio-available (ionic and/or loosely protein bound) ions. Zinc accumulation was especially high in the maculae of eyes with AMD. Internal deposit structures are especially enriched in bio-available zinc. Based on the evidence provided here we suggest that zinc plays a role in sub-RPE deposit formation in the aging human eye and possibly also in the development and/or progression of AMD.

High Concentration of Zinc in Sub-retinal Pigment Epithelial Deposits

International Nuclear Information System (INIS)

Lengyel, I.; Flinn, J.; Peto, T.; Linkous, D.; Cano, K.; Bird, A.; Lanzirotti, A.; Frederickson, C.; van Kuijk, F.

2007-01-01

One of the hallmarks of age-related macular degeneration (AMD), the leading cause of blindness in the elderly in Western societies, is the accumulation of sub-retinal pigment epithelial deposits (sub-RPE deposits), including drusen and basal laminar deposits, in Bruch's membrane (BM). The nature and the underlying mechanisms of this deposit formation are not fully understood. Because we know that zinc contributes to deposit formation in neurodegenerative diseases, we tested the hypothesis that zinc might be involved in deposit formation in AMD. Using zinc specific fluorescent probes and microprobe synchrotron X-ray fluorescence we showed that sub-RPE deposits in post-mortem human tissues contain unexpectedly high concentrations of zinc, including abundant bio-available (ionic and/or loosely protein bound) ions. Zinc accumulation was especially high in the maculae of eyes with AMD. Internal deposit structures are especially enriched in bio-available zinc. Based on the evidence provided here we suggest that zinc plays a role in sub-RPE deposit formation in the aging human eye and possibly also in the development and/or progression of AMD

[Treatment of macular hematoma complicating AMD by vitrectomy, subretinal r-TPA injection, intravitreal injection of bevacizumab combined with gas tamponade: Report of 4 cases].

Science.gov (United States)

Abboud, M; Benzerroug, M; Milazzo, S

2017-02-01

The occurrence of a subretinal hematoma in age-related macular degeneration (AMD) is a serious complication that can impact the visual prognosis with a poor functional recovery. The management of this complication remains controversial. Several therapeutic methods have been described. We report the results of four patients treated with a protocol combining: vitrectomy, subretinal injection of r-TPA 0.025mg/0.3ml, intravitreal injection of 0.05ml of bevacizumab and retinal tamponade with 20% SF6 gas. Our series consists of four patients with a submacular hematoma complicating AMD, included in succession between October 2013 and October 2014 and treated with the same treatment protocol and by the same surgeon. All patients underwent surgery within eight days after the onset of the macular hematoma. Patients with a consultation period longer than eight days did not undergo this treatment. Face down postoperative positioning was then carried out for seven days by the patients. We observed a shift in the macular hematoma in the four patients, which allowed the identification of secondary neovascularization responsible for the bleeding. The visual acuity improved in three patients from hand motion (HM) preoperatively to 2/10 at one month postoperatively. One patient maintained visual acuity 1/20 during the entire follow-up despite almost complete resorption of the subretinal hematoma. These visual acuities were stable at 6 months postoperatively. Macular subretinal hematoma can cause severe visual loss by several mechanisms. The blood accumulates between the neurosensory retina and the retinal pigment epithelium, which causes a toxic effect on the surrounding tissues, thus resulting in a loss of photoreceptors and cellular destruction in the pigment epithelium and choriocapillaris, evolving into a fibroglial scar. The therapeutic evaluation of this protocol in our series of four patients gives a favorable result. We observed an improvement in visual acuity in 3/4 of

In Vivo Assessment of the Potential for Renal Bio-Effects from the Vaporization of Perfluorocarbon Phase-Change Contrast Agents.

Science.gov (United States)

Nyankima, A Gloria; Rojas, Juan D; Cianciolo, Rachel; Johnson, Kennita A; Dayton, Paul A

2018-02-01

Low-boiling-point perfluorocarbon phase-change contrast agents (PCCAs) provide an alternative to microbubble contrast agents. Although parameter ranges related to in vivo bio-effects of microbubbles are fairly well characterized, few studies have been done to evaluate the potential of bio-effects related to PCCAs. To bridge this gap, we present an assessment of biological effects (e.g., hemorrhage) related to acoustically excited PCCAs in the rodent kidney. The presence or absence of bio-effects was observed after sonication with various perfluorocarbon core PCCAs (decafluorobutane, octafluoropropane or a 1:1 mixture) and as a function of activation pulse mechanical index (MI; minimum activation threshold, which was a moderate MI of 0.81-1.35 vs. a clinical maximum of 1.9). Bio-effects on renal tissue were assessed through hematology and histology including measurement of blood creatinine levels and the quantity of red blood cell (RBC) casts present in hematoxylin and eosin-stained kidney tissue sections after sonication. Short-term (24 h) and long-term (2 and 4 wk) analyses were performed after treatment. Results indicated that bio-effects from PCCA vaporization were not observed at lower mechanical indices. At higher mechanical indices, bio-effects were observed at 24 h, although these were not observable 2 wk after treatment. Copyright © 2018. Published by Elsevier Inc.

Leidenfrost Vapor Layers Reduce Drag without the Crisis in High Viscosity Liquids

KAUST Repository

Vakarelski, Ivan Uriev

2016-09-08

The drag coefficient CD of a solid smooth sphere moving in a fluid is known to be only a function of the Reynolds number Re and diminishes rapidly at the drag crisis around Re∼3×105. A Leidenfrost vapor layer on a hot sphere surface can trigger the onset of the drag crisis at a lower Re. By using a range of high viscosity perfluorocarbon liquids, we show that the drag reduction effect can occur over a wide range of Re, from as low as ∼600 to 105. The Navier slip model with a viscosity dependent slip length can fit the observed drag reduction and wake shape. © 2016 American Physical Society.

Leidenfrost Vapor Layers Reduce Drag without the Crisis in High Viscosity Liquids

KAUST Repository

Vakarelski, Ivan Uriev; Berry, Joseph D.; Chan, Derek Y C; Thoroddsen, Sigurdur T

2016-01-01

The drag coefficient CD of a solid smooth sphere moving in a fluid is known to be only a function of the Reynolds number Re and diminishes rapidly at the drag crisis around Re∼3×105. A Leidenfrost vapor layer on a hot sphere surface can trigger the onset of the drag crisis at a lower Re. By using a range of high viscosity perfluorocarbon liquids, we show that the drag reduction effect can occur over a wide range of Re, from as low as ∼600 to 105. The Navier slip model with a viscosity dependent slip length can fit the observed drag reduction and wake shape. © 2016 American Physical Society.

CityFlux perfluorocarbon tracer experiments

Directory of Open Access Journals (Sweden)

F. K. Petersson

2010-07-01

Full Text Available In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m.

The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site.

Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail.

The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this.

The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

Cardiopulmonary function and oxygen delivery during total liquid ventilation.

Science.gov (United States)

Tsagogiorgas, Charalambos; Alb, Markus; Herrmann, Peter; Quintel, Michael; Meinhardt, Juergen P

2011-10-01

Total liquid ventilation (TLV) with perfluorocarbons has shown to improve cardiopulmonary function in the injured and immature lung; however there remains controversy over the normal lung. Hemodynamic effects of TLV in the normal lung currently remain undetermined. This study compared changes in cardiopulmonary and circulatory function caused by either liquid or gas tidal volume ventilation. In a prospective, controlled study, 12 non-injured anesthetized, adult New Zealand rabbits were primarily conventionally gas-ventilated (CGV). After instrumentation for continuous recording of arterial (AP), central venous (CVP), left artrial (LAP), pulmonary arterial pressures (PAP), and cardiac output (CO) animals were randomized into (1) CGV group and (2) TLV group. In the TLV group partial liquid ventilation was initiated with instillation of perfluoroctylbromide (12 ml/kg). After 15 min, TLV was established for 3 hr applying a volume-controlled, pressure-limited, time-cycled ventilation mode using a double-piston configured TLV. Controls (CGV) remained gas-ventilated throughout the experiment. During TLV, heart rate, CO, PAP, MAP, CVP, and LAP as well as derived hemodynamic variables, arterial and mixed venous blood gases, oxygen delivery, PVR, and SVR did not differ significantly compared to CGV. Liquid tidal volumes suitable for long-term TLV in non-injured rabbits do not significantly impair CO, blood pressure, and oxygen dynamics when compared to CGV. Copyright © 2011 Wiley-Liss, Inc.

Subretinal Fluid Levels of Signal-Transduction Proteins and Apoptosis Molecules in Macula-Off Retinal Detachment Undergoing Scleral Buckle Surgery.

Science.gov (United States)

Carpineto, Paolo; Aharrh-Gnama, Agbeanda; Ciciarelli, Vincenzo; Borrelli, Enrico; Petti, Francesco; Aloia, Raffaella; Lamolinara, Alessia; Di Nicola, Marta; Mastropasqua, Leonardo

2016-12-01

To evaluate signal transduction and early apoptosis protein levels in subretinal fluid collected during scleral buckling surgery for macula-off rhegmatogenous retinal detachment (RRD). Our aim was to assess both their relation with RRD features and their influence on the posttreatment outcome. Thirty-three eyes of 33 RRD patients scheduled for scleral buckle surgery were enrolled in the study. Undiluted subretinal fluid samples were collected during surgery and analyzed via magnetic bead-based immunoassay. All patients underwent a complete ophthalmologic evaluation at baseline and at each follow-up visit (months 1, 3, and 6). Moreover, both at baseline and at the postsurgery month 6 visit, the patients were tested by means of spectral-domain optical coherence tomography (SD-OCT) in order to evaluate the average ganglion cell-inner plexiform complex thickness, as well as the photoreceptor inner segment/outer segment junction status. Patients' clinical features (retinal detachment size, detachment duration, and occurrence of proliferative vitreoretinopathy) were associated with several early apoptotic factors (caspase-8, caspase-9, and B-cell lymphoma 2 [Bcl-2]-associated death promoter [BAD]). Furthermore, both early apoptosis factors (caspase-8, Bcl-2, and p53) and signal-transduction proteins (ERK 1/2) were found to influence the postsurgery month 3 OCT characteristics. Signal-transduction proteins and early apoptosis proteins are associated with different clinical features and postsurgery outcomes.

Perflubron residua: 12 years following therapy

International Nuclear Information System (INIS)

Servaes, Sabah; Epelman, Monica

2009-01-01

Partial liquid ventilation therapy utilizing perfluorocarbons has been used for patients with severe respiratory distress. Perfluorocarbons such as perflubron have been demonstrated to clear from the lungs shortly after therapy. We present a 13-year-old boy with residual perflubron in his lungs, 12 years following therapy with perflubron. The imaging features are important to recognize as these patients return for additional care and imaging. (orig.)

Effects of Subretinal Gene Transfer at Different Time Points in a Mouse Model of Retinal Degeneration.

Science.gov (United States)

Dai, Xufeng; Zhang, Hua; Han, Juanjuan; He, Ying; Zhang, Yangyang; Qi, Yan; Pang, Ji-Jing

2016-01-01

Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is necessary for photoreceptors to generate an important lipid component of their membranes. The absence of LPCAT1 results in early and rapid rod and cone degeneration. Retinal degeneration 11 (rd11) mice carry a mutation in the Lpcat1 gene, and are an excellent model of early-onset rapid retinal degeneration (RD). To date, no reports have documented gene therapy administration in the rd11 mouse model at different ages. In this study, the AAV8 (Y733F)-smCBA-Lpcat1 vector was subretinally injected at postnatal day (P) 10, 14, 18, or 22. Four months after injection, immunohistochemistry and analysis of retinal morphology showed that treatment at P10 rescued about 82% of the wild-type retinal thickness. However, the diffusion of the vector and the resulting rescue were limited to an area around the injection site that was only 31% of the total retinal area. Injection at P14 resulted in vector diffusion that covered approximately 84% of the retina, and we found that gene therapy was more effective against RD when exposure to light was limited before and after treatment. We observed long-term preservation of electroretinogram (ERG) responses, and preservation of retinal structure, indicating that early treatment followed by limited light exposure can improve gene therapy effectiveness for the eyes of rd11 mice. Importantly, delayed treatment still partially preserved M-cones, but not S-cones, and M-cones in the rd11 retina appeared to have a longer window of opportunity for effective preservation with gene therapy. These results provide important information regarding the effects of subretinal gene therapy in the mouse model of LPCAT1-deficiency.

Utilization of diagnostic ultrasound and intravenous lipid-encapsulated perfluorocarbons in non-invasive targeted cardiovascular therapeutics.

Science.gov (United States)

Porter, Thomas R; Choudhury, Songita A; Xie, Feng

2016-01-01

Diagnostic ultrasound (DUS) pressures have the ability to induce inertial cavitation (IC) of systemically administered microbubbles; this bioeffect has many diagnostic and therapeutic implications in cardiovascular care. Diagnostically, commercially available lipid-encapsulated perfluorocarbons (LEP) can be utilized to improve endocardial and vascular border delineation as well as assess myocardial perfusion. Therapeutically, the liquid jets induced by IC can alter endothelial function and dissolve thrombi within the immediate vicinity of the cavitating microbubbles. The cavitating LEP can also result in the localized release of any bound therapeutic substance at the site of insonation. DUS-induced IC has been tested in pre-clinical studies to determine what effect it has on acute vascular and microvascular thrombosis as well as nitric oxide (NO) release. These pre-clinical studies have consistently shown that DUS-induced IC of LEP is effective in restoring coronary vascular and microvascular flow in acute ST segment elevation myocardial infarction (STEMI), with microvascular flow improving even if upstream large vessel flow has not been achieved. The initial clinical trials examining the efficacy of short pulse duration DUS high mechanical index impulses in patients with STEMI are underway, and preliminary studies have suggested that earlier epicardial vessel recanalization can be achieved prior to arriving in the cardiac catheterization laboratory. DUS high mechanical index impulses have also been effective in pre-clinical studies for targeting DNA delivery that has restored islet cell function in type I diabetes and restored vascular flow in the extremities downstream from a peripheral vascular occlusion. Improvements in this technique will come from three dimensional arrays for therapeutic applications, more automated delivery techniques that can be applied in the field, and use of submicron-sized acoustically activated LEP droplets that may better permeate the

Transport of Perfluorocarbon Tracers in the Cranfield Geological Carbon Sequestration Project

Science.gov (United States)

Moortgat, J.; Soltanian, M. R.; Amooie, M. A.; Cole, D. R.; Graham, D. E.; Pfiffner, S. M.; Phelps, T.

2017-12-01

A field-scale carbon dioxide (CO2) injection pilot project was conducted by the Southeast Regional Sequestration Partnership (SECARB) at Cranfield, Mississippi. Two associated campaigns in 2009 and 2010 were carried out to co-inject perfluorocarbon tracers (PFTs) and sulfur hexafluoride (SF6) with CO2. Tracers in gas samples from two observation wells were analyzed to construct breakthrough curves. We present the compiled field data as well as detailed numerical modeling of the flow and transport of CO2, brine, and introduced tracers. A high-resolution static model of the formation geology in the Detailed Area Study (DAS) was used in order to capture the impact of connected flow pathways created by fluvial channels on breakthrough curves and breakthrough times of PFTs and SF6 tracers. We use the cubic-plus-association (CPA) equation of state, which takes into account the polar nature of water molecules, to describe the phase behavior of CO2-brine-tracer mixtures. We show how the combination of multiple tracer injection pulses with detailed numerical simulations provide a powerful tool in constraining both formation properties and how complex flow pathways develop over time.

Acoustic Droplet Vaporization, Cavitation, and Therapeutic Properties of Copolymer-Stabilized Perfluorocarbon Nanoemulsions

International Nuclear Information System (INIS)

Nam, Kweon-Ho; Christensen, Douglas A.; Rapoport, Natalya; Kennedy, Anne M.

2009-01-01

Acoustic and therapeutic properties of Doxorubicin (DOX) and paclitaxel (PTX)-loaded perfluorocarbon nanoemulsions have been investigated in a mouse model of ovarian cancer. The nanoemulsions were stabilized by two biodegradable amphiphilic block copolymers that differed in the structure of the hydrophobic block. Acoustic droplet vaporization (ADV) and cavitation parameters were measured as a function of ultrasound frequency, pressure, duty cycles, and temperature. The optimal parameters that induced ADV and inertial cavitation of the formed microbubbles were used in vivo in the experiments on the ultrasound-mediated chemotherapy of ovarian cancer. A combination tumor treatment by intravenous injections of drug-loaded perfluoropentane nanoemulsions and tumor-directed 1-MHz ultrasound resulted in a dramatic decrease of ovarian or breast carcinoma tumor volume and sometimes complete tumor resolution. However, tumors often recurred three to six weeks after the treatment indicating that some cancer cells survived the treatment. The recurrent tumors proved more aggressive and resistant to the repeated therapy than initial tumors suggesting selection for the resistant cells during the first treatment.

Clinical outcomes of endoscope-assisted vitrectomy for treatment of rhegmatogenous retinal detachment

Directory of Open Access Journals (Sweden)

Yokoyama S

2017-11-01

Full Text Available Sho Yokoyama,1 Takashi Kojima,2 Toshio Mori,3 Taisuke Matsuda,1 Hiroyuki Sato,3 Norihiko Yoshida,4 Tatsushi Kaga,1 R Theodore Smith,5 Kazuo Ichikawa6 1Department of Ophthalmology, Japan Community Healthcare Organization Chukyo Hospital, Nagoya, Japan; 2Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan; 3Department of Ophthalmology, Iida Municipal Hospital, Iida, Japan; 4Department of Ophthalmology, Japanese Red Cross Gifu Hospital, Gifu, Japan; 5Department of Ophthalmology, New York University School of Medicine, New York, NY, USA; 6Chukyo Eye Clinic, Nagoya, Japan Summary: We evaluated the clinical outcomes for ophthalmic endoscope-assisted vitrectomy in consecutive patients with uncomplicated rhegmatogenous retinal detachment (RRD. The primary success rate was 98.4% (125/127 without performing a posterior drainage retinotomy or using perfluorocarbon liquids (PFCL for subretinal fluid drainage.Purpose: To investigate the clinical outcomes of endoscope-assisted vitrectomy in patients with uncomplicated RRD.Methods: We examined 127 eyes from consecutive patients who underwent repair of RRD by 23- or 25-gauge endoscope-assisted vitrectomy, with a minimum follow-up of 3 months. Eyes with the following criteria were excluded: Giant retinal tears, grade C proliferative vitreoretinopathy, dense vitreous hemorrhage, retinal detachment secondary to other ocular diseases, and prior retinal or vitreous surgery. All cases underwent subretinal fluid drainage, endolaser photocoagulation and fundus inspection were performed under ophthalmic endoscopic observation. Success rate, visual acuity, surgery time and complications were evaluated.Results: Primary and final success rate was 98.4% (125/127 and 100% (127/127, respectively, Surgery time was 59.6±26.3 minutes. The best-corrected visual acuity significantly improved from 20/100 to 20/20 (P<0.0001. There were 2 cases (1.6% of creation of a peripheral drainage retinotomy and 4

Treatment of micro air bubbles in rat adipose tissue at 25 kPa altitude exposures with perfluorocarbon emulsions and nitric oxide

DEFF Research Database (Denmark)

Randsøe, Thomas; Hyldegaard, O

2014-01-01

. The effect is ascribed to an increased solubility and transport capacity of respiratory gases in the PFC emulsion and possibly enhanced nitrogen washout through NO-increased blood flow rate and/or the removal of endothelial micro bubble nuclei precursors. Previous reports have shown that metabolic gases (i......INTRODUCTION: Perfluorocarbon emulsions (PFC) and nitric oxide (NO) releasing agents have on experimental basis demonstrated therapeutic properties in treating and preventing the formation of venous gas embolism as well as increased survival rate during decompression sickness from diving...

Use of sulfur hexafluoride and perfluorocarbon tracers in plutonium storage containers for leak detection

International Nuclear Information System (INIS)

Kung, J.K.

1998-05-01

This study involves an investigation of the feasibility of a tracer-based leak detection system for long-term interim plutonium storage. In particular, a protocol has been developed based on the use of inert tracers with varying concentrations in order to open-quotes fingerprintclose quotes or open-quotes tagclose quotes specific containers. A particular combination of tracers at specific ratios could be injected into the free volume of each container, allowing for the detection of leaks as well as determination of the location of leaking containers. Based on plutonium storage considerations, sulfur hexafluoride and four perfluorocarbon tracers were selected and should allow a wide range of viable fingerprinting combinations. A open-quotes high-lowclose quotes protocol which uses two distinct chromatographic peak areas or concentration levels, is recommended. Combinations of air exchange rates, detection durations, and detectability limits are examined in order to predict minimum tracer concentrations required for injection in storage containers

Perfluorocarbons and Gilbert syndrome (phenotype) in the C8 Health Study Population

Energy Technology Data Exchange (ETDEWEB)

Fan, Hongmin [Cancer Center, School of Public Health, West Virginia University, Morgantown, WV 265050-9190 (United States); Department of Epidemiology and Statistics, School of Public Health, Hebei United University, Hebei 063000 (China); Ducatman, Alan [Department of Occupational and Environmental Health, School of Public Health, West Virginia University (United States); Department of Medicine, School of Medicine, West Virginia University (United States); Clinical Translational Science Institute, West Virginia University (United States); Zhang, Jianjun [Department of Biostatistics, School Public Health, West Virginia University (United States)

2014-11-15

Background: Gilbert syndrome (GS) is an inherited defect of bilirubin conjugation, most commonly caused by a gene mutation for the enzyme UGT1A. GS is known to affect the metabolism and excretion of drugs and xenobiotics. Perfluorocarbon compounds (PFCs) are bio-persistent environmental contaminants that affect metabolic regulation. In this study, we examined the associations of GS phenotype and serum PFCs in the C8 Health Study Population. Materials and methods: Using 2005–2006 data from a large PFC-exposure population survey, we compared serum PFCs concentrations between GS and non GS clinical phenotypes, in a cross sectional design, adjusting for standard risk factors, including age, BMI, smoking status, socioeconomic status and gender. Results: Among 10 PFC compounds considered, only perfluorohexanoic acid (PFHxA) was seen at a significantly higher concentration in GS men and women. Conclusion: PFHxA exposure may be associated with GS. Our findings do not support increased exposure in GS for other PFCs. - Highlights: • Most serum PFCs are not associated with clinically evident Gilbert syndrome. • However, serum perfluorohexanoic acid is positively associated. • The investigation addresses the clinical presentation, not the genetic mutation.

Toxicity profiles of subretinal indocyanine green, Brilliant Blue G, and triamcinolone acetonide: a comparative study

DEFF Research Database (Denmark)

Ejstrup, Rasmus; Dornonville de la Cour, Morten; Heegaard, Steffen

2012-01-01

BACKGROUND: This study introduces a novel porcine model to examine the histopathological and electrophysiological consequences of retinotoxicity exerted by dyes commonly used for internal limiting membrane (ILM) staining. METHODS: Indocyanine green (ICG) 0.5 mg/ml, Brilliant Blue G (BBG) 0.25 mg....../ml and triamcinolone acetonide (TA) 13 mg/ml was injected subretinally in 12 vitrectomized pig eyes. At 6 weeks, retinas were examined by multifocal electroretinography (mfERG), ophthalmoscopy, fluorescein angiograpy, histopathology, and apoptosis assay. RESULTS: mfERG responses were significantly lower in ICG......-injected eyes than in healthy fellow eyes (p¿=¿0.039). The ratio between injected eyes and healthy fellow eyes was lower in the ICG group than in the BBG (p¿=¿0.009) and TA group (p¿=¿0.025). No difference between BBG and TA existed. All retinas were reattached, and fluorescein angiographies showed a window...

Effect of oxygen breathing and perfluorocarbon emulsion treatment on air bubbles in adipose tissue during decompression sickness

DEFF Research Database (Denmark)

Randsoe, T; Hyldegaard, O

2009-01-01

Decompression sickness (DCS) after air diving has been treated with success by means of combined normobaric oxygen breathing and intravascular perfluorocarbon (PFC) emulsions causing increased survival rate and faster bubble clearance from the intravascular compartment. The beneficial PFC effect...... has been explained by the increased transport capacity of oxygen and inert gases in blood. However, previous reports have shown that extravascular bubbles in lipid tissue of rats suffering from DCS will initially grow during oxygen breathing at normobaric conditions. We hypothesize that the combined...... effect of normobaric oxygen breathing and intravascular PFC infusion could lead to either enhanced extravascular bubble growth on decompression due to the increased oxygen supply, or that PFC infusion could lead to faster bubble elimination due to the increased solubility and transport capacity in blood...

Prevalence of Subretinal Drusenoid Deposits in Older Persons with and without Age-Related Macular Degeneration, by Multimodal Imaging.

Science.gov (United States)

Zarubina, Anna V; Neely, David C; Clark, Mark E; Huisingh, Carrie E; Samuels, Brian C; Zhang, Yuhua; McGwin, Gerald; Owsley, Cynthia; Curcio, Christine A

2016-05-01

To assess the prevalence of subretinal drusenoid deposits (SDD) in older adults with healthy maculas and early and intermediate age-related macular degeneration (AMD) using multimodal imaging. Cross-sectional study. A total of 651 subjects aged ≥60 years enrolled in the Alabama Study of Early Age-Related Macular Degeneration from primary care ophthalmology clinics. Subjects were imaged using spectral domain optical coherence tomography (SD OCT) of the macula and optic nerve head (ONH), infrared reflectance, fundus autofluorescence, and color fundus photographs (CFP). Eyes were assessed for AMD presence and severity using the Age-Related Eye Disease Study (AREDS) 9-step scale. Criteria for SDD presence were identification on ≥1 en face modality plus SD OCT or on ≥2 en face modalities if absent on SD OCT. Subretinal drusenoid deposits were considered present at the person level if present in 1 or both eyes. Prevalence of SDD in participants with and without AMD. Overall prevalence of SDD was 32% (197/611), with 62% (122/197) affected in both eyes. Persons with SDD were older than those without SDD (70.6 vs. 68.7 years, P = 0.0002). Prevalence of SDD was 23% in subjects without AMD and 52% in subjects with AMD (P maculae and in more than half of persons with early to intermediate AMD, even by stringent criteria. The prevalence of SDD is strongly associated with AMD presence and severity and increases with age, and its retinal topography including peripapillary involvement resembles that of rod photoreceptors. Consensus on SDD detection methods is recommended to advance our knowledge of this lesion and its clinical and biologic significance. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Feasibility of perfluorocarbon tracers (PFTs) in atmospheric source-receptor experiments

International Nuclear Information System (INIS)

Dietz, R.N.; Senum, G.I.

1984-03-01

A brief description of the perfluorocarbon tracer (PFT) system, which includes the tracers and the release equipment, the air samplers and the analyzers, is presented along with details on the research needs to provide a viable system for MATEX-scenario experiments. The present family of 2 viable PFTs needs to be increased to 5 to 6. Given the present precision of the analysis system, a one year long tracer experiment consisting of 4 hour releases every 60 hours from 5 different sites would require nearly 150 metric tons of PFTs at a cost of $15,000,000. Shortcomings in the programmable sampler include the pump, the sampling sequence control flexibility, data storage and retrieval, and the lack of remote communication capability; sampler adsorbent studies are also needed. The analytical system, including the catalyst processing bed, the chromatography column resolution, and the linearity of the detector, is in need of significant improvement. A higher resolution analysis system could significantly reduce analysis time but, more importantly, reduce tracer requirements more than 10-fold, for a cost savings potential of more than $13,000,000. A model is presented to demonstrate the feasibility of tracer material balances. Assessment of earlier long-range tracer experiments indicates the need for possibly 400 ground sampling sites requiring $8 to $14 million worth of samplers for a one-year tracer experiment. As many as six aircraft would be needed to conduct airborne model validation and material balance studies for each tracer plume

Perfluoroctano líquido como tamponante vitreorretiniano de curta duração no pós-operatório de portadores de descolamento de retina por ruptura gigante Perfluoroctane liquid as a short-term vitreous-retinal tamponade in the postoperative period in patients with retinal detachment due to giant tears

Directory of Open Access Journals (Sweden)

Marcelo Carvalho Ventura

2007-06-01

Full Text Available OBJETIVOS: Relatar os resultados de vitrectomia via pars plana com utilização de perfluocarbono líquido (Perfluoroctano-Ophtalmos®, como tamponante vítreo-retiniano de curta duração, no pós-operatório de portadores de descolamento de retina, por ruptura gigante. MÉTODOS: Estudaram-se dez desses pacientes. Todos os casos eram complicados por vitreorretinopatia proliferativa grau B ou pior com rupturas que variavam em extensão de 90º a 210º. O perfluorocarbono líquido foi introduzido, por via pars plana, com o volume necessário para ultrapassar o limite posterior da ruptura, permanecendo no pós-operatório por cinco dias, estando os pacientes em decúbito dorsal. Após esse período submetiam-se a segunda intervenção para troca do perfluorocarbono líquido para gás ou óleo de silicone. RESULTADOS: Após período de acompanhamento médio de 16,2 ± 12,4 meses (2 a 43 meses, 80% das retinas estavam aplicadas, sendo necessária a repetição desta técnica em 1 caso (10% caso e em 2 casos (20% não houve reaplicação da retina por vitreorretinopatia avançada. Houve melhora da acuidade visual em 5 casos (50%. CONCLUSÃO: Observaram-se bons resultados quanto à aplicação da retina (80% e melhora da acuidade visual (50% quando do uso do perfluorocarbono líquido como tamponante vitreorretiniano de curta duração no pós-operatório de cirurgias de descolamento de retina por rupturas gigantes.PURPOSE: To report pars plana vitrectomy results of intravitreous use of liquid perfluorocarbon as a short-term postoperative tamponade in retinal detachment due to giant tears in a series of patients. METHODS: Ten of those patients, all of them complicated by proliferative vitreoretinopathy grade B or worse, with tear extension varying from 90º to 210º were studied. Perfluorocarbon liquid was injected via pars plana until the posterior tear limit, remaining in the postoperative period during five days, with the patients in supine position

In vivo operation of the Boston 15-channel wireless subretinal visual prosthesis

Science.gov (United States)

Shire, Douglas B.; Doyle, Patrick; Kelly, Shawn K.; Gingerich, Marcus D.; Chen, Jinghua; Cogan, Stuart F.; Drohan, William A.; Mendoza, Oscar; Theogarajan, Luke; Wyatt, John; Rizzo, Joseph F.

2010-02-01

This presentation concerns the engineering development of the Boston visual prosthesis for restoring useful vision to patients blind with degenerative retinal disease. A miniaturized, hermetically-encased, 15-channel wirelessly-operated retinal prosthetic was developed for implantation and pre-clinical studies in Yucatan mini-pig animal models. The prosthesis conforms to the eye and drives a microfabricated polyimide stimulating electrode array having sputtered iridium oxide electrodes. This array is implanted into the subretinal space using a specially-designed ab externo surgical technique; the bulk of the prosthesis is on the surface of the sclera. The implanted device includes a hermetic titanium case containing a 15-channel stimulator chip; secondary power/data receiving coils surround the cornea. Long-term in vitro pulse testing was also performed on the electrodes to ensure their stability over years of operation. Assemblies were first tested in vitro to verify wireless operation of the system in biological saline using a custom RF transmitter circuit and primary coils. Stimulation pulse strength, duration and frequency were programmed wirelessly using a computer with a custom graphical user interface. Operation of the retinal implant was verified in vivo in 3 minipigs for more than three months by measuring stimulus artifacts on the eye surface using contact lens electrodes.

Intravitreal, Subretinal, and Suprachoroidal Injections: Evolution of Microneedles for Drug Delivery.

Science.gov (United States)

Hartman, Rachel R; Kompella, Uday B

Even though the very thought of an injection into the eye may be frightening, an estimated 6 million intravitreal (IVT) injections were made in the USA during 2016. With the introduction of new therapeutic agents, this number is expected to increase. In addition, drug products that are injectable in ocular compartments other than the vitreous humor are expected to enter the back of the eye market in the not so distant future. Besides the IVT route, some of the most actively investigated routes of invasive administration to the eye include periocular, subretinal, and suprachoroidal (SC) routes. While clinical efficacy is the driving force behind new injectable drug product development for the eye, safety is also being improved with time. In the case of IVT injections, the procedural guidelines have evolved over the years to improve patient comfort and reduce injection-related injury and infection. Similar advances are anticipated for other routes of administration of injectable products to the eye. In addition to procedural improvements, the design of needles, particularly those with smaller diameters, length, and controlled bevel angles are expected to improve overall safety and acceptance of injected ophthalmic drug products. A key development in this area is the introduction of microneedles of a length less than a millimeter that can target the SC space. In the future, needles with smaller diameters and lengths, potentially approaching nanodimensions, are expected to revolutionize ophthalmic disease management.

Universal Approach to Estimate Perfluorocarbons Emissions During Individual High-Voltage Anode Effect for Prebaked Cell Technologies

Science.gov (United States)

Dion, Lukas; Gaboury, Simon; Picard, Frédéric; Kiss, Laszlo I.; Poncsak, Sandor; Morais, Nadia

2018-04-01

Recent investigations on aluminum electrolysis cell demonstrated limitations to the commonly used tier-3 slope methodology to estimate perfluorocarbon (PFC) emissions from high-voltage anode effects (HVAEs). These limitations are greater for smelters with a reduced HVAE frequency. A novel approach is proposed to estimate the specific emissions using a tier 2 model resulting from individual HVAE instead of estimating monthly emissions for pot lines with the slope methodology. This approach considers the nonlinear behavior of PFC emissions as a function of the polarized anode effect duration but also integrates the change in behavior attributed to cell productivity. Validation was performed by comparing the new approach and the slope methodology with measurement campaigns from different smelters. The results demonstrate a good agreement between measured and estimated emissions as well as more accurately reflect individual HVAE dynamics occurring over time. Finally, the possible impact of this approach for the aluminum industry is discussed.

In vitro surfactant and perfluorocarbon aerosol deposition in a neonatal physical model of the upper conducting airways.

Directory of Open Access Journals (Sweden)

Estibalitz Goikoetxea

Full Text Available OBJECTIVE: Aerosol delivery holds potential to release surfactant or perfluorocarbon (PFC to the lungs of neonates with respiratory distress syndrome with minimal airway manipulation. Nevertheless, lung deposition in neonates tends to be very low due to extremely low lung volumes, narrow airways and high respiratory rates. In the present study, the feasibility of enhancing lung deposition by intracorporeal delivery of aerosols was investigated using a physical model of neonatal conducting airways. METHODS: The main characteristics of the surfactant and PFC aerosols produced by a nebulization system, including the distal air pressure and air flow rate, liquid flow rate and mass median aerodynamic diameter (MMAD, were measured at different driving pressures (4-7 bar. Then, a three-dimensional model of the upper conducting airways of a neonate was manufactured by rapid prototyping and a deposition study was conducted. RESULTS: The nebulization system produced relatively large amounts of aerosol ranging between 0.3±0.0 ml/min for surfactant at a driving pressure of 4 bar, and 2.0±0.1 ml/min for distilled water (H2Od at 6 bar, with MMADs between 2.61±0.1 µm for PFD at 7 bar and 10.18±0.4 µm for FC-75 at 6 bar. The deposition study showed that for surfactant and H2Od aerosols, the highest percentage of the aerosolized mass (∼65% was collected beyond the third generation of branching in the airway model. The use of this delivery system in combination with continuous positive airway pressure set at 5 cmH2O only increased total airway pressure by 1.59 cmH2O at the highest driving pressure (7 bar. CONCLUSION: This aerosol generating system has the potential to deliver relatively large amounts of surfactant and PFC beyond the third generation of branching in a neonatal airway model with minimal alteration of pre-set respiratory support.

Cerebral Microvascular and Systemic Effects Following Intravenous Administration of the Perfluorocarbon Emulsion Perftoran.

Science.gov (United States)

Abutarboush, Rania; Saha, Biswajit K; Mullah, Saad H; Arnaud, Francoise G; Haque, Ashraful; Aligbe, Chioma; Pappas, Georgina; Auker, Charles R; McCarron, Richard M; Moon-Massat, Paula F; Scultetus, Anke H

2016-11-18

Oxygen-carrying perfluorocarbon (PFC) fluids have the potential to increase tissue oxygenation during hypoxic states and to reduce ischemic cell death. Regulatory approval of oxygen therapeutics was halted due to concerns over vasoconstrictive side effects. The goal of this study was to assess the potential vasoactive properties of Perftoran by measuring brain pial arteriolar diameters in a healthy rat model. Perftoran, crystalloid (saline) or colloid (Hextend) solutions were administered as four sequential 30 min intravenous (IV) infusions, thus allowing an evaluation of cumulative dose-dependent effects. There were no overall changes in diameters of small-sized (<50 μm) pial arterioles within the Perftoran group, while both saline and Hextend groups exhibited vasoconstriction. Medium-sized arterioles (50-100 μm) showed minor (~8-9%) vasoconstriction within saline and Hextend groups and only ~5% vasoconstriction within the Perftoran group. For small- and medium-sized pial arterioles, the mean percent change in vessel diameters was not different among the groups. Although there was a tendency for arterial blood pressures to increase with Perftoran, pressures were not different from the other two groups. These data show that Perftoran, when administered to healthy anesthetized rats, does not cause additional vasoconstriction in cerebral pial arterioles or increase systemic blood pressure compared with saline or Hextend.

Perfluorocarbon emulsion therapy attenuates pneumococcal infection in sickle cell mice.

Science.gov (United States)

Helmi, Nawal; Andrew, Peter W; Pandya, Hitesh C

2015-05-15

Impaired immunity and tissue hypoxia-ischemia are strongly linked with Streptococcus pneumoniae pathogenesis in patients with sickle cell anemia. Perfluorocarbon emulsions (PFCEs) have high O2-dissolving capacity and can alleviate tissue hypoxia. Here, we evaluate the effects of intravenous PFCE therapy in transgenic sickle cell (HbSS) mice infected with S. pneumoniae. HbSS and C57BL/6 (control) mice intravenously infected with S. pneumoniae were treated intravenously with PFCE or phosphate-buffered saline (PBS) and then managed in either air/O2 (FiO2 proportion, 50%; hereafter referred to as the PFCE-O2 and PBS-O2 groups) or air only (hereafter, the PFCE-air and PBS-air groups) gas mixtures. Lungs were processed for leukocyte and bacterial counts and cytokine measurements. HbSS mice developed severe pneumococcal infection significantly faster than C57BL/6 mice (Kaplan-Maier analysis, P < .05). PFCE-O2-treated HbSS mice had significantly better survival at 72 hours than HBSS mice treated with PFCE-air, PBS-O2, or PBS-air (P < .05). PFCE-O2-treated HbSS mice also had significantly lower pulmonary leukocyte counts, lower interleukin 1β and interferon γ levels, and higher interleukin 10 levels than PFCE-air-treated HbSS mice. Clearance of S. pneumoniae from lungs of HbSS mice or C57BL/6 mice was not altered by PFCE treatment. Improved survival of PFCE-O₂-treated HbSS mice infected with S. pneumoniae is associated with altered pulmonary inflammation but not enhanced bacterial clearance. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Meso-pores carbon nano-tubes (CNTs) tissues-perfluorocarbons (PFCs) hybrid air-electrodes for Li-O2 battery

Science.gov (United States)

Balaish, Moran; Ein-Eli, Yair

2018-03-01

Adding immiscible perfluorocarbons (PFCs), possessing superior oxygen solubility and diffusivity, to a free-standing (metal-free and binder-free) CNTs air-electrode tissues with a meso-pore structure, fully maximized the advantages of PFCs as oxygenated-species' channels-providers. The discharge behavior of hybrid PFCs-CNT Li-O2 systems demonstrated a drastic increase in cell capacity at high current density (0.2 mA cm-2), where oxygen transport limitations are best illustrated. The results of this research revealed several key factors affecting PFCs-Li-O2 systems. The incorporation of PFCs with higher superoxide solubility and oxygen diffusivity, but more importantly higher PFCs/electrolyte miscibility, in a meso-pore air-electrode enabled better exploitation of PFCs potential. Consequently, the utilization of the air-electrode' surface area was enhanced via the formation of artificial three phase reaction zones with additional oxygen transportation routes, leading to uniform and intimate Li2O2 deposit at areas further away from the oxygen reservoir. Associated mechanisms are discussed along with insights into an improved Li-O2 battery system.

Micro-Computed Tomography Detection of Gold Nanoparticle-Labelled Mesenchymal Stem Cells in the Rat Subretinal Layer

Science.gov (United States)

Mok, Pooi Ling; Leow, Sue Ngein; Koh, Avin Ee-Hwan; Mohd Nizam, Hairul Harun; Ding, Suet Lee Shirley; Luu, Chi; Ruhaslizan, Raduan; Wong, Hon Seng; Halim, Wan Haslina Wan Abdul; Ng, Min Hwei; Idrus, Ruszymah Binti Hj.; Chowdhury, Shiplu Roy; Bastion, Catherine Mae-Lynn; Subbiah, Suresh Kumar; Higuchi, Akon; Alarfaj, Abdullah A.; Then, Kong Yong

2017-01-01

Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases. PMID:28208719

Micro-Computed Tomography Detection of Gold Nanoparticle-Labelled Mesenchymal Stem Cells in the Rat Subretinal Layer.

Science.gov (United States)

Mok, Pooi Ling; Leow, Sue Ngein; Koh, Avin Ee-Hwan; Mohd Nizam, Hairul Harun; Ding, Suet Lee Shirley; Luu, Chi; Ruhaslizan, Raduan; Wong, Hon Seng; Halim, Wan Haslina Wan Abdul; Ng, Min Hwei; Idrus, Ruszymah Binti Hj; Chowdhury, Shiplu Roy; Bastion, Catherine Mae-Lynn; Subbiah, Suresh Kumar; Higuchi, Akon; Alarfaj, Abdullah A; Then, Kong Yong

2017-02-08

Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.

Development and application of a double-piston configured, total-liquid ventilatory support device.

Science.gov (United States)

Meinhardt, J P; Quintel, M; Hirschl, R B

2000-05-01

Perfluorocarbon liquid ventilation has been shown to enhance pulmonary mechanics and gas exchange in the setting of respiratory failure. To optimize the total liquid ventilation process, we developed a volume-limited, time-cycled liquid ventilatory support, consisting of an electrically actuated, microprocessor-controlled, double-cylinder, piston pump with two separate limbs for active inspiration and expiration. Prospective, controlled, animal laboratory study, involving sequential application of conventional gas ventilation, partial ventilation (PLV), and total liquid ventilation (TLV). Research facility at a university medical center. A total of 12 normal adult New Zealand rabbits weighing 3.25+/-0.1 kg. Anesthestized rabbits were supported with gas ventilation for 30 mins (respiratory rate, 20 cycles/min; peak inspiratory pressure, 15 cm H2O; end-expiratory pressure, 5 cm H2O), then PLV was established with perflubron (12 mL/kg). After 15 mins, TLV was instituted (tidal volume, 18 mL/kg; respiratory rate, 7 cycles/min; inspiratory/expiratory ratio, 1:2 cycles/min). After 4 hrs of TLV, PLV was re-established. Of 12 animals, nine survived the 4-hr TLV period. During TLV, mean values +/- SEM were as follows: PaO2, 363+/-30 torr; PaCO2, 39+/-1.5 torr; pH, 7.39+/-0.01; static peak inspiratory pressure, 13.2+/-0.2 cm H2O; static endexpiratory pressure, 5.5+/-0.1 cm H2O. No significant changes were observed. When compared with gas ventilation and PLV, significant increases occurred in mean arterial pressure (62.4+/-3.5 torr vs. 74.0+/-1.2 torr) and central venous pressure (5.6+/-0.7 cm H2O vs. 7.8+/-0.2 cm H2O) (p piston pumps with active expiration. Considering the enhanced flow profiles, this device configuration provides advantages over others.

Thermal Dynamics in Newborn and Juvenile Models Cooled by Total Liquid Ventilation.

Science.gov (United States)

Nadeau, Mathieu; Sage, Michael; Kohlhauer, Matthias; Vandamme, Jonathan; Mousseau, Julien; Robert, Raymond; Tissier, Renaud; Praud, Jean-Paul; Walti, Herve; Micheau, Philippe

2016-07-01

Total liquid ventilation (TLV) consists in filling the lungs with a perfluorocarbon (PFC) and using a liquid ventilator to ensure a tidal volume of oxygenated, CO 2 -free and temperature-controlled PFC. Having a much higher thermal capacity than air, liquid PFCs assume that the filled lungs become an efficient heat exchanger with pulmonary circulation. The objective of the present study was the development and validation of a parametric lumped thermal model of a subject in TLV. The lungs were modeled as one compartment in which the control volume varied as a function of the tidal volume. The heat transfer in the body was modeled as seven parallel compartments representing organs and tissues. The thermal model of the lungs and body was validated with two groups of lambs of different ages and weights (newborn and juvenile) undergoing an ultrafast mild therapeutic hypothermia induction by TLV. The model error on all animals yielded a small mean error of -0.1 ±0.4  (°)C for the femoral artery and 0.0 ±0.1   (°)C for the pulmonary artery. The resulting experimental validation attests that the model provided an accurate estimation of the systemic arterial temperature and the venous return temperature. This comprehensive thermal model of the lungs and body has the advantage of closely modeling the rapid thermal dynamics in TLV. The model can explain how the time to achieve mild hypothermia between newborn and juvenile lambs remained similar despite of highly different physiological and ventilatory parameters. The strength of the model is its strong relationship with the physiological parameters of the subjects, which suggests its suitability for projection to humans.

Effect of surfactant and partial liquid ventilation treatment on gas exchange and lung mechanics in immature lambs: influence of gestational age.

Science.gov (United States)

Rey-Santano, Carmen; Mielgo, Victoria; Gastiasoro, Elena; Valls-i-Soler, Adolfo; Murgia, Xabier

2013-01-01

Surfactant (SF) and partial liquid ventilation (PLV) improve gas exchange and lung mechanics in neonatal RDS. However, variations in the effects of SF and PLV with degree of lung immaturity have not been thoroughly explored. Experimental Neonatal Respiratory Physiology Research Unit, Cruces University Hospital. Prospective, randomized study using sealed envelopes. 36 preterm lambs were exposed (at 125 or 133-days of gestational age) by laparotomy and intubated. Catheters were placed in the jugular vein and carotid artery. All the lambs were assigned to one of three subgroups given: 20 mL/Kg perfluorocarbon and managed with partial liquid ventilation (PLV), surfactant (Curosurf®, 200 mg/kg) or (3) no pulmonary treatment (Controls) for 3 h. Cardiovascular parameters, blood gases and pulmonary mechanics were measured. In 125-day gestation lambs, SF treatment partially improved gas exchange and lung mechanics, while PLV produced significant rapid improvements in these parameters. In 133-day lambs, treatments with SF or PLV achieved similarly good responses. Neither surfactant nor PLV significantly affected the cardiovascular parameters. SF therapy response was more effective in the older gestational age group whereas the effectiveness of PLV therapy was not gestational age dependent.

Perfluorocarbons in the global atmosphere: tetrafluoromethane, hexafluoroethane, and octafluoropropane

Directory of Open Access Journals (Sweden)

J. Mühle

2010-06-01

Full Text Available We present atmospheric baseline growth rates from the 1970s to the present for the long-lived, strongly infrared-absorbing perfluorocarbons (PFCs tetrafluoromethane (CF₄, hexafluoroethane (C₂F₆, and octafluoropropane (C₃F₈ in both hemispheres, measured with improved accuracies (~1–2% and precisions (<0.3%, or <0.2 ppt (parts per trillion dry air mole fraction, for CF₄; <1.5%, or <0.06 ppt, for C₂F₆; <4.5%, or <0.02 ppt, for C₃F₈ within the Advanced Global Atmospheric Gases Experiment (AGAGE. Pre-industrial background values of 34.7±0.2 ppt CF₄ and 0.1±0.02 ppt C₂F₆ were measured in air extracted from Greenland ice and Antarctic firn. Anthropogenic sources are thought to be primary aluminum production (CF₄, C₂F₆, C₃F₈, semiconductor production (C₂F₆, CF₄, C₃F₈ and refrigeration use (C₃F₈. Global emissions calculated with the AGAGE 2-D 12-box model are significantly higher than most previous emission estimates. The sum of CF₄ and C₂F₆ emissions estimated from aluminum production and non-metal production are lower than observed global top-down emissions, with gaps of ~6 Gg/yr CF₄ in recent years. The significant discrepancies between previous CF₄, C₂F₆, and C₃F₈ emission estimates and observed global top-down emissions estimated from AGAGE measurements emphasize the need for more accurate, transparent, and complete emission reporting, and for verification with atmospheric measurements to assess the emission sources of these long-lived and potent greenhouse gases, which alter the radiative budget of the atmosphere, essentially permanently, once emitted.

High-intensity focused ultrasound sonothrombolysis: the use of perfluorocarbon droplets to achieve clot lysis at reduced acoustic power.

Science.gov (United States)

Pajek, Daniel; Burgess, Alison; Huang, Yuexi; Hynynen, Kullervo

2014-09-01

The purpose of this study was to evaluate use of intravascular perfluorocarbon droplets to reduce the sonication power required to achieve clot lysis with high-intensity focused ultrasound. High-intensity focused ultrasound with droplets was initially applied to blood clots in an in vitro flow apparatus, and inertial cavitation thresholds were determined. An embolic model for ischemic stroke was used to illustrate the feasibility of this technique in vivo. Recanalization with intravascular droplets was achieved in vivo at 24 ± 5% of the sonication power without droplets. Recanalization occurred in 71% of rabbits that received 1-ms pulsed sonications during continuous intravascular droplet infusion (p = 0.041 vs controls). Preliminary experiments indicated that damage was confined to the ultrasonic focus, suggesting that tolerable treatments would be possible with a more tightly focused hemispheric array that allows the whole focus to be placed inside of the main arteries in the human brain. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Micro-Computed Tomography Detection of Gold Nanoparticle-Labelled Mesenchymal Stem Cells in the Rat Subretinal Layer

Directory of Open Access Journals (Sweden)

Pooi Ling Mok

2017-02-01

Full Text Available Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.

Cell Labeling for 19F MRI: New and Improved Approach to Perfluorocarbon Nanoemulsion Design

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Jonathan Williams

2013-09-01

Full Text Available This report describes novel perfluorocarbon (PFC nanoemulsions designed to improve ex vivo cell labeling for 19F magnetic resonance imaging (MRI. 19F MRI is a powerful non-invasive technique for monitoring cells of the immune system in vivo, where cells are labeled ex vivo with PFC nanoemulsions in cell culture. The quality of 19F MRI is directly affected by the quality of ex vivo PFC cell labeling. When co-cultured with cells for longer periods of time, nanoemulsions tend to settle due to high specific weight of PFC oils (1.5–2.0 g/mL. This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro. To solve this problem, novel PFC nanoemulsions are reported which demonstrate lack of sedimentation and high stability under cell labeling conditions. They are monodisperse, have small droplet size (~130 nm and low polydispersity (<0.15, show a single peak in the 19F nuclear magnetic resonance spectrum at −71.4 ppm and possess high fluorine content. The droplet size and polydispersity remained unchanged after 160 days of follow up at three temperatures (4, 25 and 37 °C. Further, stressors such as elevated temperature in the presence of cells, and centrifugation, did not affect the nanoemulsion droplet size and polydispersity. Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented.

Successful displacement of a traumatic submacular hemorrhage in a 13-year-old boy treated by vitrectomy, subretinal injection of tissue plasminogen activator and intravitreal air tamponade: a case report.

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Doi, Shinichiro; Kimura, Shuhei; Morizane, Yuki; Shiode, Yusuke; Hosokawa, Mio; Hirano, Masayuki; Hosogi, Mika; Fujiwara, Atsushi; Miyamoto, Kazuhisa; Shiraga, Fumio

2015-08-07

The natural course of submacular hemorrhage resulting from traumatic choroidal rupture generally has a poor outcome unless treated. The intravitreal injection of gas only or gas with recombinant tissue plasminogen activator (rt-PA) has been reported to be effective, but has also been reported to induce severe complications such as retinal detachment and vitreous hemorrhage. Recently, we reported a safe and effective procedure for treating submacular hemorrhage due to polypoidal choroidal vasculopathy (PCV) with a low dose of rt-PA. Here we report the application of this procedure to a case of traumatic submacular hemorrhage in a 13-year-old boy, which achieved a good visual outcome. A 13-year-old Japanese boy presented with a thick submacular hemorrhage in his left eye as a result of blunt trauma from being hit by a sinker. Best-corrected visual acuity (BCVA) was assessed as only able to perceive hand motions. We carried out a vitrectomy, subretinal injection of 4,000 IU rt-PA (6.9 μg) and air tamponade. The day after surgery, most of the submacular hemorrhage had moved to the inferior periphery. One month after the surgery, we observed cataract formation, thin remnants of the submacular hemorrhage and juxtafoveal choroidal rupture. We carried out cataract surgery and injected bevacizumab intravitreally to prevent the development of choroidal neovascularization. Two months after the second surgery, the submacular hemorrhage had totally disappeared and the patient had a BCVA of 20/40. Vitrectomy, subretinal injection of rt-PA, and intravitreal air tamponade may be a promising strategy for treating traumatic submacular hemorrhage in young patients.

DYNAMISM OF DOT SUBRETINAL DRUSENOID DEPOSITS IN AGE-RELATED MACULAR DEGENERATION DEMONSTRATED WITH ADAPTIVE OPTICS IMAGING.

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Zhang, Yuhua; Wang, Xiaolin; Godara, Pooja; Zhang, Tianjiao; Clark, Mark E; Witherspoon, C Douglas; Spaide, Richard F; Owsley, Cynthia; Curcio, Christine A

2018-01-01

To investigate the natural history of dot subretinal drusenoid deposits (SDD) in age-related macular degeneration, using high-resolution adaptive optics scanning laser ophthalmoscopy. Six eyes of four patients with intermediate age-related macular degeneration were studied at baseline and 1 year later. Individual dot SDD within the central 30° retina were examined with adaptive optics scanning laser ophthalmoscopy and optical coherence tomography. A total of 269 solitary SDD were identified at baseline. Over 12.25 ± 1.18 months, all 35 Stage 1 SDD progressed to advanced stages. Eighteen (60%) Stage 2 lesions progressed to Stage 3 and 12 (40%) remained at Stage 2. Of 204 Stage 3 SDD, 12 (6.4%) disappeared and the rest remained. Twelve new SDD were identified, including 6 (50%) at Stage 1, 2 (16.7%) at Stage 2, and 4 (33.3%) at Stage 3. The mean percentage of the retina affected by dot SDD, measured by the adaptive optics scanning laser ophthalmoscopy, increased in 5/6 eyes (from 2.31% to 5.08% in the most changed eye) and decreased slightly in 1/6 eye (from 10.67% to 10.54%). Dynamism, the absolute value of the areas affected by new and regressed lesions, ranged from 0.7% to 9.3%. Adaptive optics scanning laser ophthalmoscopy reveals that dot SDD, like drusen, are dynamic.

Gene expression changes in the retina following subretinal injection of human neural progenitor cells into a rodent model for retinal degeneration.

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Jones, Melissa K; Lu, Bin; Saghizadeh, Mehrnoosh; Wang, Shaomei

2016-01-01

Retinal degenerative diseases (RDDs) affect millions of people and are the leading cause of vision loss. Although treatment options for RDDs are limited, stem and progenitor cell-based therapies have great potential to halt or slow the progression of vision loss. Our previous studies have shown that a single subretinal injection of human forebrain derived neural progenitor cells (hNPCs) into the Royal College of Surgeons (RCS) retinal degenerate rat offers long-term preservation of photoreceptors and visual function. Furthermore, neural progenitor cells are currently in clinical trials for treating age-related macular degeneration; however, the molecular mechanisms of stem cell-based therapies are largely unknown. This is the first study to analyze gene expression changes in the retina of RCS rats following subretinal injection of hNPCs using high-throughput sequencing. RNA-seq data of retinas from RCS rats injected with hNPCs (RCS(hNPCs)) were compared to sham surgery in RCS (RCS(sham)) and wild-type Long Evans (LE(sham)) rats. Differential gene expression patterns were determined with in silico analysis and confirmed with qRT-PCR. Function, biologic, cellular component, and pathway analyses were performed on differentially expressed genes and investigated with immunofluorescent staining experiments. Analysis of the gene expression data sets identified 1,215 genes that were differentially expressed between RCS(sham) and LE(sham) samples. Additionally, 283 genes were differentially expressed between the RCS(hNPCs) and RCS(sham) samples. Comparison of these two gene sets identified 68 genes with inverse expression (termed rescue genes), including Pdc, Rp1, and Cdc42ep5. Functional, biologic, and cellular component analyses indicate that the immune response is enhanced in RCS(sham). Pathway analysis of the differential expression gene sets identified three affected pathways in RCS(hNPCs), which all play roles in phagocytosis signaling. Immunofluorescent staining

[Blood plasma protein adsorption capacity of perfluorocarbon emulsion stabilized by proxanol 268 (in vitro and in vivo studies)].

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Sklifas, A N; Zhalimov, V K; Temnov, A A; Kukushkin, N I

2012-01-01

The adsorption abilities of the perfluorocarbon emulsion stabilized by Proxanol 268 were investigated in vitro and in vivo. In vitro, the saturation point for the blood plasma proteins was nearly reached after five minutes of incubation of the emulsion with human/rabbit blood plasma and was stable for all incubation periods studied. The decrease in volume ratio (emulsion/plasma) was accompanied by the increase in the adsorptive capacity of the emulsion with maximal values at 1/10 (3.2 and 1.5 mg of proteins per 1 ml of the emulsion, for human and rabbit blood plasma, respectively) that was unchanged at lower ratios. In vivo, in rabbits, intravenously injected with the emulsion, the proteins with molecular masses of 12, 25, 32, 44, 55, 70, and 200 kDa were adsorbed by the emulsion (as in vitro) if it was used 6 hours or less before testing. More delayed testing (6 h) revealed elimination of proteins with molecular masses of 25 and 44 kDa and an additional pool of adsorpted new ones of 27, 50, and 150 kDa. Specific adsorptive capacity of the emulsion enhanced gradually after emulsion injection and reached its maximum (3.5-5 mg of proteins per 1 ml of the emulsion) after 24 hours.

Interim Results of a Multicenter Trial with the New Electronic Subretinal Implant Alpha AMS in 15 Patients Blind from Inherited Retinal Degenerations.

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Stingl, Katarina; Schippert, Ruth; Bartz-Schmidt, Karl U; Besch, Dorothea; Cottriall, Charles L; Edwards, Thomas L; Gekeler, Florian; Greppmaier, Udo; Kiel, Katja; Koitschev, Assen; Kühlewein, Laura; MacLaren, Robert E; Ramsden, James D; Roider, Johann; Rothermel, Albrecht; Sachs, Helmut; Schröder, Greta S; Tode, Jan; Troelenberg, Nicole; Zrenner, Eberhart

2017-01-01

Purpose: We assessed the safety and efficacy of a technically advanced subretinal electronic implant, RETINA IMPLANT Alpha AMS, in end stage retinal degeneration in an interim analysis of two ongoing prospective clinical trials. The purpose of this article is to describe the interim functional results (efficacy). Methods: The subretinal visual prosthesis RETINA IMPLANT Alpha AMS (Retina Implant AG, Reutlingen, Germany) was implanted in 15 blind patients with hereditary retinal degenerations at four study sites with a follow-up period of 12 months (www.clinicaltrials.gov NCT01024803 and NCT02720640). Functional outcome measures included (1) screen-based standardized 2- or 4-alternative forced-choice (AFC) tests of light perception, light localization, grating detection (basic grating acuity (BaGA) test), and Landolt C-rings; (2) gray level discrimination; (3) performance during activities of daily living (ADL-table tasks). Results: Implant-mediated light perception was observed in 13/15 patients. During the observation period implant mediated localization of visual targets was possible in 13/15 patients. Correct grating detection was achieved for spatial frequencies of 0.1 cpd (cycles per degree) in 4/15; 0.33 cpd in 3/15; 0.66 cpd in 2/15; 1.0 cpd in 2/15 and 3.3 cpd in 1/15 patients. In two patients visual acuity (VA) assessed with Landolt C- rings was 20/546 and 20/1111. Of 6 possible gray levels on average 4.6 ± 0.8 (mean ± SD, n = 10) were discerned. Improvements (power ON vs. OFF) of ADL table tasks were measured in 13/15 patients. Overall, results were stable during the observation period. Serious adverse events (SAEs) were reported in 4 patients: 2 movements of the implant, readjusted in a second surgery; 4 conjunctival erosion/dehiscence, successfully treated; 1 pain event around the coil, successfully treated; 1 partial reduction of silicone oil tamponade leading to distorted vision (silicon oil successfully refilled). The majority of adverse events (AEs

Interim Results of a Multicenter Trial with the New Electronic Subretinal Implant Alpha AMS in 15 Patients Blind from Inherited Retinal Degenerations

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Katarina Stingl

2017-08-01

Full Text Available Purpose: We assessed the safety and efficacy of a technically advanced subretinal electronic implant, RETINA IMPLANT Alpha AMS, in end stage retinal degeneration in an interim analysis of two ongoing prospective clinical trials. The purpose of this article is to describe the interim functional results (efficacy.Methods: The subretinal visual prosthesis RETINA IMPLANT Alpha AMS (Retina Implant AG, Reutlingen, Germany was implanted in 15 blind patients with hereditary retinal degenerations at four study sites with a follow-up period of 12 months (www.clinicaltrials.gov NCT01024803 and NCT02720640. Functional outcome measures included (1 screen-based standardized 2- or 4-alternative forced-choice (AFC tests of light perception, light localization, grating detection (basic grating acuity (BaGA test, and Landolt C-rings; (2 gray level discrimination; (3 performance during activities of daily living (ADL-table tasks.Results: Implant-mediated light perception was observed in 13/15 patients. During the observation period implant mediated localization of visual targets was possible in 13/15 patients. Correct grating detection was achieved for spatial frequencies of 0.1 cpd (cycles per degree in 4/15; 0.33 cpd in 3/15; 0.66 cpd in 2/15; 1.0 cpd in 2/15 and 3.3 cpd in 1/15 patients. In two patients visual acuity (VA assessed with Landolt C- rings was 20/546 and 20/1111. Of 6 possible gray levels on average 4.6 ± 0.8 (mean ± SD, n = 10 were discerned. Improvements (power ON vs. OFF of ADL table tasks were measured in 13/15 patients. Overall, results were stable during the observation period. Serious adverse events (SAEs were reported in 4 patients: 2 movements of the implant, readjusted in a second surgery; 4 conjunctival erosion/dehiscence, successfully treated; 1 pain event around the coil, successfully treated; 1 partial reduction of silicone oil tamponade leading to distorted vision (silicon oil successfully refilled. The majority of adverse events

Statistical data analysis method for multi-zonal airflow measurement using multiple kinds of perfluorocarbon tracer gas

Energy Technology Data Exchange (ETDEWEB)

Okuyama, Hiroyasu; Onishi, Yoshinori [Institute of Technology, Shimizu Corporation, 4-17, Etchujima 3-chome, Koto-ku, Tokyo 135-8530 (Japan); Tanabe, Shin-ichi [School of Science and Engineering, Department of Architecture, Waseda University, 3-4-1 Okubo, Shinjyuku-ku, Tokyo 169-8555 (Japan); Kashihara, Seiichi [R and D Laboratories, Asahi Kasei Homes Corporation, 2-1, Samejima Fuji-shi, Shizuoka 416-8501 (Japan)

2009-03-15

Conventional multi-zonal ventilation measurement methods by multiple types of perfluorocarbon tracers use a number of different gases equal to the number of zones (n). The possible n x n+n airflows are estimated from the mass balance of the gases and the airflow balance. However, some airflows may not occur because of inter-zonal geometry, and the introduction of unnecessary, unknown parameters can impair the accuracy of the estimation. Also, various error factors often yield an irrational negative airflow rate. Conventional methods are insufficient for the evaluation of error. This study describes a way of using the least-squares technique to improve the precision of estimation and to evaluate reliability. From the equations' residual, the error variance-covariance matrix {lambda}{sub q} of the estimated airflow rate error is deduced. In addition, the coefficient of determinant using the residual sum of squares and total variation is introduced. Furthermore, the error matrix{sub m}{lambda}{sub q} from the measurement errors in the gas concentration and gas emission rate is deduced. The discrepancy ratio of the model premises is defined by dividing the diagonal elements of the former by those of the latter. Moreover, the index of irrationality of the estimated negative airflow rate is defined, based on the different results of the three estimation methods. Some numerical experiments are also carried out to verify the flow rate estimation and the reliability evaluation theory. (author)

USE OF PERFLUOROCARBON TRACER (PFT) TECHNOLOGY FOR SUBSURFACE BARRIER INTEGRITY VERIFICATION AT THE WALDO TEST SITE

Energy Technology Data Exchange (ETDEWEB)

SULLIVAN,T.; HEISER,J.; SENUM,G.; MILLIAN,L.

2000-02-27

Researchers from Brookhaven National Laboratory (BNL) tested perfluorocarbon (PFT) gas tracers on a subsurface barrier with known flaws at the Waldo test facility [operated by Science and Engineering Associates, Inc (SEA)]. The tests involved the use of five unique PFT tracers with a different tracer injected along the interior of each wall of the barrier. A fifth tracer was injected exterior to the barrier to examine the validity of diffusion controlled transport of the PFTs. The PFTs were injected for three days at a nominal flow rate of 15 cm{sup 3}/min and a concentrations in the range of a few hundred ppm. Approximately 65 liters of air laced with tracer was injected for each tracer. The tracers were able to accurately detect the presence of the engineered flaws. Two flaws were detected on the north and east walls and lane flaw was detected on the south and west walls. In addition, one non-engineered flaw at the seam between the north and east walls was also detected. The use of multiple tracers provided independent confirmation of the flaws and permitted a distinction between tracers arriving at a monitoring port after being released from a nearby flaw and non-engineered flaws. The PFTs detected the smallest flaw, 0.5 inches in diameter. Visual inspection of the data showed excellent agreement with the known flaw locations and the relative size of the flaws was accurately estimated.

Valved versus nonvalved cannula small-gauge pars plana vitrectomy for repair of retinal detachments with Grade C proliferative vitreoretinopathy

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Oellers P

2016-05-01

Full Text Available Patrick Oellers, Sandra Stinnett, Paul Hahn Duke Eye Center, Duke University School of Medicine, Durham, NC, USA Purpose: Valved cannulas are a recent addition to small-gauge pars plana vitrectomy (PPV and provide stable intraocular fluidics. The goal of this study was to compare outcomes and postoperative complication rates of valved vs nonvalved cannula small-gauge PPV for repair of retinal detachments (RDs complicated by Grade C proliferative vitreoretinopathy (PVR.Methods: A retrospective chart review of 364 consecutive eyes with either valved or nonvalved cannula PPV for RD repair was performed. The primary outcomes were single surgery and final anatomic success and change in best-corrected visual acuity for repair of RDs complicated by Grade C PVR.Results: We identified 36 eyes in the valved group and 31 eyes in the nonvalved group with Grade C PVR RD. The single surgery success was 83% vs 77% (P=0.555 and the final anatomic success was 94% vs 87% (P=0.404 in the valved vs nonvalved eyes, respectively. The mean final visual acuity gain was −0.36 logarithm of the minimum angle of resolution (logMAR; approximate Early Treatment Diabetes Retinopathy Study [ETDRS] score =17 letters in valved eyes vs −0.33 logMAR (approximate ETDRS score =16 letters in nonvalved eyes (P=0.81. Postoperative complication rates including postoperative day 1 hypotony, hypertony, and anterior chamber fibrin formation; postoperative retention of intraocular or subretinal perfluorocarbon liquid; and subsequent epiretinal membrane peel were not statistically different between groups.Conclusion: Valved cannula PPV yields equivalent visual acuity and anatomic outcomes without increased postoperative complication rates compared to traditional nonvalved cannula PPV for Grade C PVR-associated RD repair. Keywords: 23 gauge, 25 gauge, PVR, RD, chronic, single surgery success, final anatomic success

Paramagnetic perfluorocarbon-filled albumin-(Gd-DTPA) microbubbles for the induction of focused-ultrasound-induced blood-brain barrier opening and concurrent MR and ultrasound imaging.

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Liao, Ai-Ho; Liu, Hao-Li; Su, Chia-Hao; Hua, Mu-Yi; Yang, Hung-Wei; Weng, Yu-Ting; Hsu, Po-Hung; Huang, Sheng-Min; Wu, Shih-Yen; Wang, Hsin-Ell; Yen, Tzu-Chen; Li, Pai-Chi

2012-05-07

This paper presents new albumin-shelled Gd-DTPA microbubbles (MBs) that can concurrently serve as a dual-modality contrast agent for ultrasound (US) imaging and magnetic resonance (MR) imaging to assist blood-brain barrier (BBB) opening and detect intracerebral hemorrhage (ICH) during focused ultrasound brain drug delivery. Perfluorocarbon-filled albumin-(Gd-DTPA) MBs were prepared with a mean diameter of 2320 nm and concentration of 2.903×10(9) MBs ml(-1) using albumin-(Gd-DTPA) and by sonication with perfluorocarbon (C(3)F(8)) gas. The albumin-(Gd-DTPA) MBs were then centrifuged and the procedure was repeated until the free Gd(3+) ions were eliminated (which were detected by the xylenol orange sodium salt solution). The albumin-(Gd-DTPA) MBs were also characterized and evaluated both in vitro and in vivo by US and MR imaging. Focused US was used with the albumin-(Gd-DTPA) MBs to induce disruption of the BBB in 18 rats. BBB disruption was confirmed with contrast-enhanced T(1)-weighted turbo-spin-echo sequence MR imaging. Heavy T(2)*-weighted 3D fast low-angle shot sequence MR imaging was used to detect ICH. In vitro US imaging experiments showed that albumin-(Gd-DTPA) MBs can significantly enhance the US contrast in T(1)-, T(2)- and T(2)*-weighted MR images. The r(1) and r(2) relaxivities for Gd-DTPA were 7.69 and 21.35 s(-1)mM(-1), respectively, indicating that the MBs represent a positive contrast agent in T(1)-weighted images. In vivo MR imaging experiments on 18 rats showed that focused US combined with albumin-(Gd-DTPA) MBs can be used to both induce disruption of the BBB and detect ICH. To compare the signal intensity change between pure BBB opening and BBB opening accompanying ICH, albumin-(Gd-DTPA) MB imaging can provide a ratio of 5.14 with significant difference (p = 0.026), whereas Gd-DTPA imaging only provides a ratio of 2.13 and without significant difference (p = 0.108). The results indicate that albumin-(Gd-DTPA) MBs have potential as a US/MR dual

MRI and intraocular tamponade media

Energy Technology Data Exchange (ETDEWEB)

Manfre, I. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Fabbri, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Avitabile, T. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Biondi, P. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Reibaldi, A. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Pero, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy))

1993-05-01

Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, flurosilicone oil, or perfluoro-carbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment. (orig.)

MRI and intraocular tamponade media

International Nuclear Information System (INIS)

Manfre, I.; Fabbri, G.; Avitabile, T.; Biondi, P.; Reibaldi, A.; Pero, G.

1993-01-01

Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, flurosilicone oil, or perfluoro-carbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment. (orig.)

Formation of hydrogen fluoride by gamma and beta sterilisation in medical devices containing perfluoroheptane

International Nuclear Information System (INIS)

Zuendorf, Josef; Kremer, Stefan; Grueger, Thomas

2008-01-01

Infusion of hexadecafluoroheptane, a liquid perfluorocarbon released from repaired Althane dialysers was found to be the most probable reason for the deaths of 53 dialysis patients reported in the year 2001. This study focuses on toxic decomposition products generated due to gamma and beta sterilisation of hexadecafluoroheptane. The responsible dialysers were sterilised with a maximum dose of 45 kGy gamma irradiation. We investigated the influence of both 20-500 kGy gamma and beta irradiation on perfluoroheptane. Analysis of the irradiated samples verified the decomposition of perfluoroheptane in dependence on the dose of irradiation. Beta irradiation resulted in a higher degree of decomposition than the same dose of gamma irradiation. As decomposition products, hydrogen fluoride, CO 2 , and one saturated fluorinated hydrocarbon which could not be analysed exactly were identified. Even at 20 kGy gamma irradiation hydrogen fluoride was detectable. Our results provide evidence that hydrogen fluoride is generated as a highly toxic decomposition product when perfluoroheptane is sterilised with gamma irradiation as it was applied on the affected dialysers. There is no evidence of other toxic degradation products especially perfluoroisobutylene. Therefore, hydrogen fluoride or the dissociated fluoride ions might act as a toxic agent when medical devices containing liquid perfluorocarbons are sterilised by irradiation

USING PERFLUOROCARBON TRACERS FOR VERIFICATION OF CAP AND COVER SYSTEMS PERFORMANCE

International Nuclear Information System (INIS)

HEISER, J.; SULLIVAN, T.

2001-01-01

subsurface barriers (1,2). The technology uses perfluorocarbon tracers (PFTs) to determine flaws (e.g., holes or cracks) and high permeability areas in subsurface barriers. Gaseous tracers are injected on one side of the barrier and searched for on the opposite side of the barrier. The sampling grid, concentration, and time of arrival of the tracer(s) on the opposite side are used to determine the size and location of flaws and relative permeability of the barrier. In addition, there are multiple tracers available, which allows different tracers to be injected in different quadrants of the barrier. This yields additional information on transport phenomena of the barrier

Interleukin and growth factor levels in subretinal fluid in rhegmatogenous retinal detachment: a case-control study.

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Lukas J A G Ricker

Full Text Available BACKGROUND: Rhegmatogenous retinal detachment (RRD is a major cause of visual loss in developed countries. Proliferative vitreoretinopathy (PVR, an eye-sight threatening complication of RRD surgery, resembles a wound-healing process with inflammation, scar tissue formation, and membrane contraction. This study was performed to determine the possible involvement of a wide range of cytokines in the future development of PVR, and to identify predictors of PVR and visual outcome. METHODOLOGY: A multiplex immunoassay was used for the simultaneous detection of 29 different cytokines in subretinal fluid samples from patients with primary RRD. Of 306 samples that were collected and stored in our BioBank between 2001 and 2008, 21 samples from patients who developed postoperative PVR were compared with 54 age-, sex-, and storage-time-matched RRD control patients who had an uncomplicated postoperative course during the overall follow-up period. FINDINGS: Levels of IL-1α, IL-2, IL-3, IL-6, VEGF, and ICAM-1 were significantly higher (P0.05. Multivariate logistic regression analysis revealed that IL-3 (P = 0.001, IL-6 (P = 0.047, ICAM-1 (P = 0.010, and preoperative visual acuity (P = 0.026 were independent predictors of postoperative PVR. Linear regression analysis showed that ICAM-1 (P = 0.005 and preoperative logMAR visual acuity (P = 0.001 were predictive of final visual outcome after primary RRD repair. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that after RRD onset an exaggerated response of certain cytokines may predispose to PVR. Sampling at a time close to the onset of primary RRD may thus provide clues as to which biological events may initiate the development of PVR and, most importantly, may provide a means for therapeutic control.

Subretinal hyper-reflective material seen on optical coherence tomography as a biomarker for disease monitoring in age-related macular degeneration

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Lee, H. B.; Ong, B. B.; Katta, M.; Yvon, C.; Lu, L.; Zakri, R.; Patel, N.

2018-03-01

Subretinal hyper-reflective material (SHRM) seen on optical coherence tomography (OCT) is thought to be a collection of fibrous tissues and vascular networks that are identified in age-related macular degeneration (ARMD). We have carried out a retrospective analysis of 91 OCT scans of neovascular ARMD subtypes including classic and occult choroidal neovascularization (CNV) and retinal angiomatous proliferation (RAP). All three subtypes received ranibizumab, an anti-vascular endothelial growth factor (Anti-VEGF) intravitreal injections on an as-needed basis following the loading doses. Volumes of SHRM were calculated using caliper measurements of maximal height and length of SHRM seen on OCT. The ellipsoid formula derived from tumour models was used to calculate the volume. It was found that occult CNV and RAP have larger SHRM volumes than those of classic CNV. SHRM volumes reduced overall following loading doses of Anti-VEGF injections at 4 months in all three subtypes. However, a rebound increase in volume was noticed in both occult CNV and RAP cohort at 12 months despite the initial, steeper reductions in the subtypes. These findings were consistent with the data seen in volume measurement using Topcon's automated segmentation algorithm in a smaller cohort of patients. We propose that SHRM should be used as a potential biomarker to quantify both disease progression and prognosis of neovascular ARMD alongside other conventional methods.

Spectral-domain optical coherence tomography analysis of persistent subretinal fluid after scleral buckling surgery for macula-off retinal detachment

Science.gov (United States)

Gharbiya, M; Malagola, R; Mariotti, C; Parisi, F; De Vico, U; Ganino, C; Grandinetti, F

2015-01-01

Purpose To determine the predictive value of markers for persistent subretinal fluid (SRF) absorption and the influence of subfoveal fluid on visual outcome after scleral buckle (SB) surgery for rhegmatogenous retinal detachment (RRD). Patients and methods This was a retrospective, observational study. We reviewed the medical records of 64 eyes of 64 patients who underwent SB surgery for macula-off RRD. Patients underwent clinical examination and spectral-domain optical coherence tomography before surgery, at 1 month and every 3 months postoperatively. The height and width of SRF bleb(s) were measured over time. Results Persistent SRF at 1 month was observed in 40 eyes (62.5%). SRF blebs were first detected 1.7±2.2 months postoperatively. In 29 cases that could be fully followed up, SRF blebs were completely absorbed 7.8±4.4 months postoperatively. Resolution of fluid was associated with an improvement of VA (P=0.003). Serial measurements of SRF bleb size showed that bleb width decreased significantly at all time points during the 12-month follow-up period (P0.05). The cut-off value of the bleb width-to-height ratio level for predicting bleb absorption at 6 months was 7, with 89% sensitivity and 83% specificity. Conclusions Visual improvement may occur with late resolution of residual subfoveal fluid. A bleb width-to-height ratio >7 indicates a higher risk of SRF to persist beyond 6 months after surgery. PMID:26139048

Prevalence of subretinal drusenoid deposits in older persons with and without age-related macular degeneration, by multimodal imaging

Science.gov (United States)

Zarubina, Anna V.; Neely, David C.; Clark, Mark E.; Huisingh, Carrie E.; Samuels, Brian C.; Zhang, Yuhua; McGwin, Gerald; Owsley, Cynthia; Curcio, Christine A.

2015-01-01

Purpose To assess the prevalence of subretinal drusenoid deposits (SDD) in older adults with healthy maculas and early and intermediate age-related macular degeneration (AMD) using multimodal imaging. Design Cross-sectional study. Participants A total of 651 subjects aged ≥60 years enrolled in the Alabama Study of Early Age-Related Macular Degeneration from primary care ophthalmology clinics. Methods Subjects were imaged using spectral domain optical coherence tomography (SD-OCT) of the macula and optic nerve head (ONH), infrared reflectance, fundus autofluorescence, and color fundus photographs (CFP). Eyes were assessed for AMD presence and severity using the AREDS 9-step scale. Criteria for SDD presence were identification on ≥1 en-face modality plus SD-OCT or on ≥2 en-face modalities if absent on SD-OCT. SDD were considered present at the person-level if present in 1 or both eyes. Main outcomes measures Prevalence of SDD in participants with and without AMD. Results Overall prevalence of SDD was 32% (197/611), with 62% (122/197) affected in both eyes. Persons with SDD were older than those without SDD (70.6 vs. 68.7 years, p =0.0002). Prevalence of SDD was 23% in subjects without AMD and 52% in subjects with AMD (pmaculae and in more than half of persons with early to intermediate AMD, even by stringent criteria. The prevalence of SDD is strongly associated with AMD presence and severity and increases with age, and its retinal topography including peripapillary involvement resembles that of rod photoreceptors. Consensus on SDD detection methods is recommended to advance our knowledge of this lesion and its clinical and biologic significance. PMID:26875000

Characterization of Rod Function Phenotypes Across a Range of Age-Related Macular Degeneration Severities and Subretinal Drusenoid Deposits.

Science.gov (United States)

Flynn, Oliver J; Cukras, Catherine A; Jeffrey, Brett G

2018-05-01

To examine spatial changes in rod-mediated function in relationship to local structural changes across the central retina in eyes with a spectrum of age-related macular degeneration (AMD) disease severity. Participants were categorized into five AMD severity groups based on fundus features. Scotopic thresholds were measured at 14 loci spanning ±18° along the vertical meridian from one eye of each of 42 participants (mean = 71.7 ± 9.9 years). Following a 30% bleach, dark adaptation was measured at eight loci (±12°). Rod intercept time (RIT) was defined from the time to detect a -3.1 log cd/m2 stimulus. RITslope was defined from the linear fit of RIT with decreasing retinal eccentricity. The presence of subretinal drusenoid deposits (SDD), ellipsoid (EZ) band disruption, and drusen at the test loci was evaluated using optical coherence tomography. Scotopic thresholds indicated greater rod function loss in the macula, which correlated with increasing AMD group severity. RITslope, which captures the spatial change in the rate of dark adaptation, increased with AMD severity (P < 0.0001). Three rod function phenotypes emerged: RF1, normal rod function; RF2, normal scotopic thresholds but slowed dark adaptation; and RF3, elevated scotopic thresholds with slowed dark adaptation. Dark adaptation was slowed at all loci with SDD or EZ band disruption, and at 32% of loci with no local structural changes. Three rod function phenotypes were defined from combined measurement of scotopic threshold and dark adaptation. Spatial changes in dark adaptation across the macula were captured with RITslope, which may be a useful outcome measure for functional studies of AMD.

Physicochemical characteristics of PFC surfactants for dry decontamination

Energy Technology Data Exchange (ETDEWEB)

Oh, Won Jin; Lee, Chi Woo [Korea University, Seoul (Korea)

2001-04-01

Even the trace amount of the used nuclear fuels of high radioactivity are hazardous to the earth and humans. Perfluorocarbons and perfluorocarbon surfactants are emerging to be efficient chemicals in the dry decontamination process of the used fuels of high radioactivity. The theme was undertaken to increase the knowledge on perfluorocarbon surfactants to develop the perfluorocarbon system in the dry decontamination process in Korea. Several cationic and anionic pfc surfactants were synthesized. Effects of pfc surfactants on electrochemical etching of silicon were investigated to form porous silicons. Forces were measured between silicon surfaces and AFM tip in the absence and presence of pfc surfactants. 7 refs., 10 figs. (Author)

Effects of respiratory rate and tidal volume on gas exchange in total liquid ventilation.

Science.gov (United States)

Bull, Joseph L; Tredici, Stefano; Fujioka, Hideki; Komori, Eisaku; Grotberg, James B; Hirschl, Ronald B

2009-01-01

Using a rabbit model of total liquid ventilation (TLV), and in a corresponding theoretical model, we compared nine tidal volume-respiratory rate combinations to identify a ventilator strategy to maximize gas exchange, while avoiding choked flow, during TLV. Nine different ventilation strategies were tested in each animal (n = 12): low [LR = 2.5 breath/min (bpm)], medium (MR = 5 bpm), or high (HR = 7.5 bpm) respiratory rates were combined with a low (LV = 10 ml/kg), medium (MV = 15 ml/kg), or high (HV = 20 ml/kg) tidal volumes. Blood gases and partial pressures, perfluorocarbon gas content, and airway pressures were measured for each combination. Choked flow occurred in all high respiratory rate-high volume animals, 71% of high respiratory rate-medium volume (HRMV) animals, and 50% of medium respiratory rate-high volume (MRHV) animals but in no other combinations. Medium respiratory rate-medium volume (MRMV) resulted in the highest gas exchange of the combinations that did not induce choke. The HRMV and MRHV animals that did not choke had similar or higher gas exchange than MRMV. The theory predicted this behavior, along with spatial and temporal variations in alveolar gas partial pressures. Of the combinations that did not induce choked flow, MRMV provided the highest gas exchange. Alveolar gas transport is diffusion dominated and rapid during gas ventilation but is convection dominated and slow during TLV. Consequently, the usual alveolar gas equation is not applicable for TLV.

The effect of isovolemic hemodilution with oxycyte, a perfluorocarbon emulsion, on cerebral blood flow in rats.

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Zhong-jin Yang

Full Text Available BACKGROUND: Cerebral blood flow (CBF is auto-regulated to meet the brain's metabolic requirements. Oxycyte is a perfluorocarbon emulsion that acts as a highly effective oxygen carrier compared to blood. The aim of this study is to determine the effects of Oxycyte on regional CBF (rCBF, by evaluating the effects of stepwise isovolemic hemodilution with Oxycyte on CBF. METHODOLOGY: Male rats were intubated and ventilated with 100% O(2 under isoflurane anesthesia. The regional (striatum CBF (rCBF was measured with a laser doppler flowmeter (LDF. Stepwise isovolemic hemodilution was performed by withdrawing 4ml of blood and substituting the same volume of 5% albumin or 2 ml Oxycyte plus 2 ml albumin at 20-minute intervals until the hematocrit (Hct values reached 5%. PRINCIPAL FINDINGS: In the albumin-treated group, rCBF progressively increased to approximately twice its baseline level (208+/-30% when Hct levels were less than 10%. In the Oxycyte-treated group on the other hand, rCBF increased by significantly smaller increments, and this group's mean rCBF was only slightly higher than baseline (118+/-18% when Hct levels were less than 10%. Similarly, in the albumin-treated group, rCBF started to increase when hemodilution with albumin caused the CaO(2 to decrease below 17.5 ml/dl. Thereafter, the increase in rCBF was accompanied by a nearly proportional decrease in the CaO(2 level. In the Oxycyte-treated group, the increase in rCBF was significantly smaller than in the albumin-treated group when the CaO(2 level dropped below 10 ml/dl (142+/-20% vs. 186+/-26%, and rCBF returned to almost baseline levels (106+/-15 when the CaO(2 level was below 7 ml/dl. CONCLUSIONS/SIGNIFICANCE: Hemodilution with Oxycyte was accompanied with higher CaO(2 and PO(2 than control group treated with albumin alone. This effect may be partially responsible for maintaining relatively constant CBF and not allowing the elevated blood flow that was observed with albumin.

Macular Atrophy Development and Subretinal Drusenoid Deposits in Anti-Vascular Endothelial Growth Factor Treated Age-Related Macular Degeneration.

Science.gov (United States)

Zarubina, Anna V; Gal-Or, Orly; Huisingh, Carrie E; Owsley, Cynthia; Freund, K Bailey

2017-12-01

To explore the association between presence of subretinal drusenoid deposits (SDD) at baseline in eyes with neovascular age-related macular degeneration (nAMD) with the development of macular atrophy (MA) during anti-vascular endothelial growth factor (VEGF) therapy. There were 74 eyes without pre-existing MA receiving anti-VEGF therapy for nAMD for 2 years or longer analyzed. At least two image modalities that included spectral-domain optical coherence tomography, near-infrared reflectance, fluorescein angiography, and color fundus photos were used to assess for SDD presence, phenotype (dot and ribbon), and location, neovascularization type, and MA. Logistic regression models using generalized estimating equations assessed the association between SDD and the development of MA adjusting for age, neovascularization type, and choroidal thickness. SDD were present in 46 eyes (63%) at baseline. MA developed in 38 eyes (51%) during the mean of 4.7 ± 1.2 years of follow-up. Compared with eyes without SDD, those with SDD at baseline were 3.0 times (95% confidence interval [CI] 1.1-8.5, P = 0.0343) more likely to develop MA. Eyes with SDD present in the inferior macula and inferior extramacular fields at baseline were 3.0 times and 6.5 times more likely to develop MA at follow-up than eyes without SDD in these locations (95% CI 1.0-8.9, P = 0.0461 and 95% CI 1.3-32.4, P = 0.0218, respectively). MA development was not associated with a specific SDD phenotype. MA frequently developed in eyes during anti-VEGF treatment. SDD were independently associated with MA development. The extension of SDD into the inferior fundus, particularly in the inferior extramacular field, conferred higher odds of subsequent MA development.

Dashed line relaxing retinotomy in the management of retinal detachment with anterior proliferative vitreoretinopathy

Directory of Open Access Journals (Sweden)

Tsen CL

2015-04-01

Full Text Available Chui-Lien Tsen,1 Yu-Harn Horng,1 Shwu-Jiuan Sheu1,2 1Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; 2School of Medicine, National Yang-Ming University, Taipei, Taiwan Background: We describe the anatomical and functional outcomes of eyes that underwent a modified technique of relaxing retinotomy, dashed line relaxing retinotomy, in the management of retinal detachment with anterior proliferative vitreoretinopathy.Methods: We retrospectively reviewed 54 consecutive eyes in 52 patients who received pars plana vitrectomy with relaxing retinotomy during retinal detachment repair. Perfluorocarbon liquid (PFCL was used as a standard procedure to stabilize the retina during retinotomy to prevent slippage or inversion of the posterior flap. If PFCL was not available due to economic reasons, dashed line relaxing retinotomy was performed instead. Best-corrected visual acuity, slit-lamp biomicroscopy, intraocular pressure measurement, lens status, and fundus examination were analyzed. We excluded patients who were followed up <4 months.Results: Regarding anatomical success rates and visual outcomes, we found no significant differences between patients treated with intraoperative PFCL and those treated with dashed line relaxing retinotomy without PFCL.Conclusion: Compared to the simple and efficient PFCL-assisted relaxing retinotomy, dashed relaxing retinotomy is not the first choice when PFCL is available. Based on our results, this modified technique may offer an alternative in patients with anterior proliferative vitreoretinopathy for whom PFCL is not available. Keywords: perfluorocarbon liquid, PFCL 

LIQUID-LIQUID EXTRACTION COLUMNS

Science.gov (United States)

Thornton, J.D.

1957-12-31

This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

Liquids and liquid mixtures

CERN Document Server

Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

2013-01-01

Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

Liquid-liquid displacement in slippery liquid-infused membranes (SLIMs)

OpenAIRE

Bazyar, Hanieh; Lv, Pengyu; Wood, Jeffery A.; Porada, Slawomir; Lohse, Detlef; Lammertink, Rob G. H.

2018-01-01

Liquid-infused membranes inspired by slippery liquid-infused porous surfaces (SLIPS) have been recently introduced to membrane technology. The gating mechanism of these membranes is expected to give rise to anti-fouling properties and multi-phase transport capabilities. However, the long-term retention of the infusion liquid has not yet been explored. To address this issue, we investigate the retention of the infusion liquid in slippery liquid-infused membranes (SLIMs) via liquid-liquid displ...

Vitreoretinal surgery in advanced coats disease.

Science.gov (United States)

Ozdamar, Yasemin; Berker, Nilufer; Batman, Cosar; Zilelioglu, Orhan

2009-01-01

To report the outcomes of vitreoretinal surgery for a patient with total retinal detachment and a subretinal nodule associated with Coats disease (CD). A 20-year-old woman stage 3B CD underwent vitreoretinal surgery with triamcinolone acetonide-assisted pars plana vitrectomy, limited retinotomy, removal of the subretinal nodule and membrane, endolaser photocoagulation, and silicone oil tamponade. The surgical outcomes were observed. Retinal attachment was achieved after vitreoretinal surgery, removal of the subretinal membrane, and endoresection of the subretinal fibrous nodule. No intraoperative or postoperative complications occurred due to the surgical technique. The retina remained attached during the postoperative follow-up period of 6 months. Vitreoretinal surgery is an effective surgical technique that provides successful reattachment of the retina and enables endoresection of the subretinal fibrous nodule in eyes with advanced CD. It also prevents the devastating intraocular complications leading to enucleation.

CASH AND LIQUIDITY/LIQUIDITY AND LIQUIDITY RATIO

Directory of Open Access Journals (Sweden)

BEATRIX LIGHEZAN BREUER

2012-12-01

Full Text Available The present paper aims to present the correlation as well as the differences between liquidity/cash and liquidity ratio in terms of economic entities. Researches on this topic are based on the opinions of some specialists in accounting and in the economic-financial analysis, as well as on the national legal stipulations and the ones set out in the International Accounting Standards, the Financial report, respectively. The object of this paper is represented by the correlation between liquidity/cash and liquidity ratios representing the liquidity as current assets, assets implied in the determination of liquidity ratios. The end of the paper consists of the conclusions drawn from the issues presented in the paper but also our views on this research topic.

Our Treatment Results of Circumscribed and Diffuse Choroidal Hemangiomas

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Esra Savku

2013-08-01

Full Text Available Purpose: To discuss our treatment results of choroidal hemangiomas. Material and Method: The records of 39 cases of choroidal hemangioma followed up at our clinic between July 1999–October 2012 were reviewed retrospectively. Asymptomatic cases were followed up. Symptomatic cases with subretinal fluid and impaired vision received treatment. Results: Mean age of the 39 patients was 44 (12-80 years. Thirty-five of 39 cases had circumscribed choroidal hemangioma, and 4 cases had diffuse choroidal hemangioma. Sturge-Weber syndrome was present in 3 cases with diffuse choroidal hemangioma. Cases with circumscribed choroidal hemangioma and minimal subretinal fluid were treated with TTT in 11 cases, PDT in 12 cases, and PDT+TTT in 1 case. Cases with circumscribed choroidal hemangioma and excessive subretinal fluid were treated with Ru-106 plaque radiotherapy in 1 case, Ru-106 plaque radiotherapy+TTT in 1 case, EBRT in 3 cases, and TTT+EBRT in 1 case. One painful blind eye with neovascular glaucoma and complicated cataract was enucleated. Cases with diffuse choroidal hemangioma and excessive subretinal fluid were treated with Ru-106 plaque radiotherapy+TTT in 1 case and EBRT in 1 case. Ahmed glaucoma valve implantation and FAKO emulsification were applied to a case with neovascular glaucoma and complicated cataract. Complete resorption of subretinal fluid was achieved in 23 (72% of treated 32 cases. When mean initial tumor thickness was 2.6 mm (0.5-6, mean final tumor thickness was 1.4 mm (0-6. When mean initial visual acuity (LogMAR was 1.5 (0-3, mean final visual acuity was 1.1 (0-3. No recurrence was observed. Discussion: The amount of the subretinal fluid determines the method of treatment in circumscribed choroidal hemangioma. While TTT and PDT are effective treatment modalities for minimal subretinal fluid, plaque radiotherapy and EBRT are applied in cases with excessive subretinal fluid. Combination therapies may be necessary according to the

An update: improvements in imaging perfluorocarbon-mounted plant leaves with implications for studies of plant pathology, physiology, development and cell biology.

Science.gov (United States)

Littlejohn, George R; Mansfield, Jessica C; Christmas, Jacqueline T; Witterick, Eleanor; Fricker, Mark D; Grant, Murray R; Smirnoff, Nicholas; Everson, Richard M; Moger, Julian; Love, John

2014-01-01

Plant leaves are optically complex, which makes them difficult to image by light microscopy. Careful sample preparation is therefore required to enable researchers to maximize the information gained from advances in fluorescent protein labeling, cell dyes and innovations in microscope technologies and techniques. We have previously shown that mounting leaves in the non-toxic, non-fluorescent perfluorocarbon (PFC), perfluorodecalin (PFD) enhances the optical properties of the leaf with minimal impact on physiology. Here, we assess the use of the PFCs, PFD, and perfluoroperhydrophenanthrene (PP11) for in vivo plant leaf imaging using four advanced modes of microscopy: laser scanning confocal microscopy (LSCM), two-photon fluorescence microscopy, second harmonic generation microscopy, and stimulated Raman scattering (SRS) microscopy. For every mode of imaging tested, we observed an improved signal when leaves were mounted in PFD or in PP11, compared to mounting the samples in water. Using an image analysis technique based on autocorrelation to quantitatively assess LSCM image deterioration with depth, we show that PP11 outperformed PFD as a mounting medium by enabling the acquisition of clearer images deeper into the tissue. In addition, we show that SRS microscopy can be used to image PFCs directly in the mesophyll and thereby easily delimit the "negative space" within a leaf, which may have important implications for studies of leaf development. Direct comparison of on and off resonance SRS micrographs show that PFCs do not to form intracellular aggregates in live plants. We conclude that the application of PFCs as mounting media substantially increases advanced microscopy image quality of living mesophyll and leaf vascular bundle cells.

Treatment of micro air bubbles in rat adipose tissue at 25 kPa altitude exposures with perfluorocarbon emulsions and nitric oxide.

Science.gov (United States)

Randsøe, Thomas; Hyldegaard, O

2014-01-01

Perfluorocarbon emulsions (PFC) and nitric oxide (NO) releasing agents have on experimental basis demonstrated therapeutic properties in treating and preventing the formation of venous gas embolism as well as increased survival rate during decompression sickness from diving. The effect is ascribed to an increased solubility and transport capacity of respiratory gases in the PFC emulsion and possibly enhanced nitrogen washout through NO-increased blood flow rate and/or the removal of endothelial micro bubble nuclei precursors. Previous reports have shown that metabolic gases (i.e., oxygen in particular) and water vapor contribute to bubble growth and stabilization during altitude exposures. Accordingly, we hypothesize that the administration of PFC and NO donors upon hypobaric pressure exposures either (1) enhance the bubble disappearance rate through faster desaturation of nitrogen, or in contrast (2) promote bubble growth and stabilization through an increased oxygen supply. In anesthetized rats, micro air bubbles (containing 79% nitrogen) of 4-500 nl were injected into exposed abdominal adipose tissue. Rats were decompressed in 36 min to 25 kPa (~10,376 m above sea level) and bubbles studied for 210 min during continued oxygen breathing (FIO2 = 1). Rats were administered PFC, NO, or combined PFC and NO. In all groups, most bubbles grew transiently, followed by a stabilization phase. There were no differences in the overall bubble growth or decay between groups or when compared with previous data during oxygen breathing alone at 25 kPa. During extreme altitude exposures, the contribution of metabolic gases to bubble growth compromises the therapeutic effects of PFC and NO, but PFC and NO do not induce additional bubble growth.

Estimation of bias with the single-zone assumption in measurement of residential air exchange using the perfluorocarbon tracer gas method.

Science.gov (United States)

Van Ryswyk, K; Wallace, L; Fugler, D; MacNeill, M; Héroux, M È; Gibson, M D; Guernsey, J R; Kindzierski, W; Wheeler, A J

2015-12-01

Residential air exchange rates (AERs) are vital in understanding the temporal and spatial drivers of indoor air quality (IAQ). Several methods to quantify AERs have been used in IAQ research, often with the assumption that the home is a single, well-mixed air zone. Since 2005, Health Canada has conducted IAQ studies across Canada in which AERs were measured using the perfluorocarbon tracer (PFT) gas method. Emitters and detectors of a single PFT gas were placed on the main floor to estimate a single-zone AER (AER(1z)). In three of these studies, a second set of emitters and detectors were deployed in the basement or second floor in approximately 10% of homes for a two-zone AER estimate (AER(2z)). In total, 287 daily pairs of AER(2z) and AER(1z) estimates were made from 35 homes across three cities. In 87% of the cases, AER(2z) was higher than AER(1z). Overall, the AER(1z) estimates underestimated AER(2z) by approximately 16% (IQR: 5-32%). This underestimate occurred in all cities and seasons and varied in magnitude seasonally, between homes, and daily, indicating that when measuring residential air exchange using a single PFT gas, the assumption of a single well-mixed air zone very likely results in an under prediction of the AER. The results of this study suggest that the long-standing assumption that a home represents a single well-mixed air zone may result in a substantial negative bias in air exchange estimates. Indoor air quality professionals should take this finding into consideration when developing study designs or making decisions related to the recommendation and installation of residential ventilation systems. © 2014 Her Majesty the Queen in Right of Canada. Indoor Air published by John Wiley & Sons Ltd Reproduced with the permission of the Minister of Health Canada.

Effect of perfluorohexane on the expression of cellular adhesion molecules and surfactant protein A in human mesothelial cells in vitro.

Science.gov (United States)

Haufe, Dirk; Dahmen, Klaus G; Tiebel, Oliver; Hübler, Matthias; Koch, Thea

2011-08-01

The intraperitoneal instillation of perfluorocarbons augmented systemic oxygenation and was protective in mesenteric ischemia-reperfusion and experimental lung injury. To study biocompatibility and potential anti-inflammatory effects of intraperitoneal perfluorocarbons, we evaluated the influence of perfluorohexane and/or inflammatory stimuli on human mesothelial cells in vitro. Perfluorohexane exposure neither impaired cell viability nor induced cellular activation. TNFα enhanced ICAM-1 expression, which was not attenuated by simultaneous perfluorohexane treatment. Concentration of intracellular surfactant protein A tended to be higher in perfluorohexane treated cells compared to controls. Our in vitro data add further evidence that intraperitoneal perfluorocarbon application is feasible without adverse local effects.

A new animal model of choriodal neovascularization

DEFF Research Database (Denmark)

Kiilgaard, J.F.; Andersen, Mads V. Nis; Wiencke, A.K.

2005-01-01

ophthalmology, age-related macular degeneration, Bruch's membrane, retinal pigment epithelium, choroidal neovascularization, subretinal neovascularization......ophthalmology, age-related macular degeneration, Bruch's membrane, retinal pigment epithelium, choroidal neovascularization, subretinal neovascularization...

PREFACE: Functionalized Liquid Liquid Interfaces

Science.gov (United States)

Girault, Hubert; Kornyshev, Alexei A.; Monroe, Charles W.; Urbakh, Michael

2007-09-01

Most natural processes take place at interfaces. For this reason, surface science has been a focal point of modern research. At solid-liquid interfaces one can induce various species to adsorb or react, and thus may study interactions between the substrate and adsorbates, kinetic processes, optical properties, etc. Liquid-liquid interfaces, formed by immiscible liquids such as water and oil, have a number of distinctive features. Both sides of the interface are amenable to detailed physical and chemical analysis. By chemical or electrochemical means, metal or semiconductor nanoparticles can be formed or localised at the interface. Surfactants can be used to tailor surface properties, and also to place organic molecular or supermolecular constructions at the boundary between the liquids. Electric fields can be used to drive ions from one fluid to another, or even change the shape of the interface itself. In many cases, both liquids are optically transparent, making functionalized liquid-liquid interfaces promising for various optical applications based on the transmission or reflection of light. An advantage common to most of these systems is self-assembly; because a liquid-liquid interface is not mechanically constrained like a solid-liquid interface, it can easily access its most stable state, even after it has been driven far from equilibrium. This special issue focuses on four modes of liquid-liquid interfacial functionalization: the controlled adsorption of molecules or nanoparticles, the formation of adlayers or films, electrowetting, and ion transfer or interface-localized reactions. Interfacial adsorption can be driven electrically, chemically, or mechanically. The liquid-liquid interface can be used to study how anisotropic particles orient at a surface under the influence of a field, how surfactants interact with other adsorbates, and how nanoparticles aggregate; the transparency of the interface also makes the chirality of organic adsorbates amenable to

The effect of the perfluorocarbon emulsion Oxycyte on platelet count and function in the treatment of decompression sickness in a swine model.

Science.gov (United States)

Cronin, William A; Senese, Angela L; Arnaud, Francoise G; Regis, David P; Auker, Charles R; Mahon, Richard T

2016-09-01

Decompression from elevated ambient pressure is associated with platelet activation and decreased platelet counts. Standard treatment for decompression sickness (DCS) is hyperbaric oxygen therapy. Intravenous perfluorocarbon (PFC) emulsion is a nonrecompressive therapy being examined that improves mortality in animal models of DCS. However, PFC emulsions are associated with a decreased platelet count. We used a swine model of DCS to study the effect of PFC therapy on platelet count, function, and hemostasis. Castrated male swine (n = 50) were fitted with a vascular port, recovered, randomized, and compressed to 180 feet of sea water (fsw) for 31 min followed by decompression at 30 fsw/min. Animals were observed for DCS, administered 100% oxygen, and treated with either emulsified PFC Oxycyte (DCS-PFC) or isotonic saline (DCS-NS). Controls underwent the same procedures, but were not compressed (Sham-PFC and Sham-NS). Measurements of platelet count, thromboelastometry, and coagulation were obtained 1 h before compression and 1, 24, 48, 96, 168 and 192 h after treatment. No significant changes in normalized platelet counts were observed. Prothrombin time was elevated in DCS-PFC from 48 to 192 h compared with DCS-NS, and from 96 to 192 h compared with Sham-PFC. Normalized activated partial thromboplastin time was also elevated in DCS-PFC from 168 to 192 h compared with Sham-PFC. No bleeding events were noted. DCS treated with PFC (Oxycyte) does not impact platelet numbers, whole blood clotting by thromboelastometry, or clinical bleeding. Late changes in prothrombin time and activated partial thromboplastin time associated with PFC use in both DCS therapy and controls warrant further investigation.

Measurement of differences in pO2 in response to perfluorocarbon/carbogen in FSa and NFSa murine fibrosarcomas with low-frequency electron paramagnetic resonance oximetry.

Science.gov (United States)

Halpern, H J; Yu, C; Peric, M; Barth, E D; Karczmar, G S; River, J N; Grdina, D J; Teicher, B A

1996-05-01

We have used very low-frequency electron paramagnetic resonance (EPR) oximetry to measure the change in oxygen concentration (delta pO2) due to change in breathing atmosphere in FSa and NFSa fibrosarcomas implanted in the legs of C3H mice infused with perfluoro-octylbromine (PFOB). Measurements in each tumor were made before and after the administration of the high-density (47% v/v) perfluorocarbon PFOB, perflubron (Alliance Pharmaceutical Corporation, San Diego, CA). Measurements in each tumor were also made, after the administration of the PFOB, both before (PFOB/air) and after the administration of carbogen (95% O2 + 5% CO2, PFOB/carbogen). Large changes (delta p02) relative to PFOB/air oxygenation were seen with the administration of PFOB/carbogen. No significant difference in oxygen concentration was seen between air-breathing mice with and without PFOB. The mean delta pO2 for FSa tumors was 13 +/- 6 torr, while the mean for NFSa fibrosarcomas was 28 +/- 7 torr. There were such large intertumor differences that the trend toward a smaller change in the more hypoxic FSa tumors was not significant (P = 0.13). This paper describes a novel method of measuring differences in oxygenation in tumor tissues. The results of such measurements indicate large differences in pO2 response to different breathing atmospheres in PFOB-infused tumors of similar histology. The intertumor delta pO2 differences may correlate with differences in radiation response.

Liquidity risk and contagion for liquid funds

OpenAIRE

Darolles , Serge; Dudek , Jeremy; Le Fol , Gaëlle

2014-01-01

Fund managers face liquidity problems but they have to distinguish the market liquidity risk implied by their assets and the funding liquidity risk. This latter is due to both the liquidity mismatch between assets and liabilities and the redemption risk due to the possible outflows from clients. The main contribution of this paper is the analysis of contagion looking at common market liquidity problems to detect funding liquidity problems. Using the CDS Bond Spread basis as a liquidity indica...

Application of Ultrasound to Selectively Localize Nanodroplets for Targeted Imaging and Therapy

Directory of Open Access Journals (Sweden)

Paul A. Dayton

2006-07-01

Full Text Available Lipid-coated perfluorocarbon nanodroplets are submicrometer-diameter liquid-filled droplets with proposed applications in molecularly targeted therapeutics and ultrasound (US imaging. Ultrasonic molecular imaging is unique in that the optimal application of these agents depends not only on the surface chemistry, but also on the applied US field, which can increase receptor-ligand binding and membrane fusion. Theory and experiments are combined to demonstrate the displacement of perfluorocarbon nanoparticles in the direction of US propagation, where a traveling US wave with a peak pressure on the order of megapascals and frequency in the megahertz range produces a particle translational velocity that is proportional to acoustic intensity and increases with increasing center frequency. Within a vessel with a diameter on the order of hundreds of micrometers or larger, particle velocity on the order of hundreds of micrometers per second is produced and the dominant mechanism for droplet displacement is shown to be bulk fluid streaming. A model for radiation force displacement of particles is developed and demonstrates that effective particle displacement should be feasible in the microvasculature. In a flowing system, acoustic manipulation of targeted droplets increases droplet retention. Additionally, we demonstrate the feasibility of US-enhanced particle internalization and therapeutic delivery.

From Funding Liquidity to Market Liquidity

DEFF Research Database (Denmark)

Dick-Nielsen, Jens; Lund, Jesper; Gyntelberg, Jacob

This paper shows empirically that funding liquidity drives market liquidity. As it becomes harder to secure term funding in the money markets, liquidity deteriorates in the Danish bond market. We show that the first principal component of bond market liquidity is driven by the market makers...... for other European government bonds using MTS data. The findings suggest that regulatory bond based liquidity buffers for banks will have limited effectiveness....

Experimental (solid + liquid) or (liquid + liquid) phase equilibria of (amine + nitrile) binary mixtures

International Nuclear Information System (INIS)

Domanska, Urszula; Marciniak, Malgorzata

2007-01-01

(Solid + liquid) phase diagrams have been determined for (hexylamine, or octylamine, or 1,3-diaminopropane + acetonitrile) mixtures. Simple eutectic systems have been observed in these mixtures. (Liquid + liquid) phase diagrams have been determined for (octylamine, or decylamine + propanenitrile, or + butanenitrile) mixtures. Mixtures with propanenitrile and butanenitrile show immiscibility in the liquid phase with an upper critical solution temperature, UCST. (Solid + liquid) phase diagrams have been correlated using NRTL, NRTL 1, Wilson and UNIQUAC equations. (Liquid + liquid) phase diagrams have been correlated using NRTL equation

Ternary (liquid + liquid) equilibria of {trifluorotris(perfluoroethyl)phosphate based ionic liquids + thiophene + heptane}

International Nuclear Information System (INIS)

Marciniak, Andrzej; Królikowski, Marek

2012-01-01

Highlights: ► Ternary (liquid + liquid) equilibria for 3 ionic liquid + thiophene + heptane systems. ► The influence of ionic liquid structure on phase diagrams is discussed. ► High selectivity for separation of heptane/thiophene is observed. - Abstract: Ternary (liquid + liquid) equilibria for three systems containing ionic liquids {(4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate, 1-(2-methoxyethyl)-1-methylpiperidinium trifluorotris(perfluoroethyl)phosphate, 1-(2-methoxyethyl)-1-methylpyrrolidinium trifluorotris(perfluoroethyl)phosphate) + thiophene + heptane} have been determined at T = 298.15 K. All systems showed high solubility of thiophene in the ionic liquid and low solubility of heptane. The solute distribution coefficient and the selectivity were calculated for all systems. High values of selectivity were obtained. The experimental results have been correlated using NRTL model. The influence of ionic liquid structure on phase equilibria is discussed.

Liquid-Liquid Extraction in Systems Containing Butanol and Ionic Liquids – A Review

OpenAIRE

Kubiczek Artur; Kamiński Władysław

2017-01-01

Room-temperature ionic liquids (RTILs) are a moderately new class of liquid substances that are characterized by a great variety of possible anion-cation combinations giving each of them different properties. For this reason, they have been termed as designer solvents and, as such, they are particularly promising for liquid-liquid extraction, which has been quite intensely studied over the last decade. This paper concentrates on the recent liquid-liquid extraction studies involving ionic liqu...

EIAV-based retinal gene therapy in the shaker1 mouse model for usher syndrome type 1B: development of UshStat.

Directory of Open Access Journals (Sweden)

Marisa Zallocchi

Full Text Available Usher syndrome type 1B is a combined deaf-blindness condition caused by mutations in the MYO7A gene. Loss of functional myosin VIIa in the retinal pigment epithelia (RPE and/or photoreceptors leads to blindness. We evaluated the impact of subretinally delivered UshStat, a recombinant EIAV-based lentiviral vector expressing human MYO7A, on photoreceptor function in the shaker1 mouse model for Usher type 1B that lacks a functional Myo7A gene. Subretinal injections of EIAV-CMV-GFP, EIAV-RK-GFP (photoreceptor specific, EIAV-CMV-MYO7A (UshStat or EIAV-CMV-Null (control vectors were performed in shaker1 mice. GFP and myosin VIIa expression was evaluated histologically. Photoreceptor function in EIAV-CMV-MYO7A treated eyes was determined by evaluating α-transducin translocation in photoreceptors in response to low light intensity levels, and protection from light induced photoreceptor degeneration was measured. The safety and tolerability of subretinally delivered UshStat was evaluated in macaques. Expression of GFP and myosin VIIa was confirmed in the RPE and photoreceptors in shaker1 mice following subretinal delivery of the EIAV-CMV-GFP/MYO7A vectors. The EIAV-CMV-MYO7A vector protected the shaker1 mouse photoreceptors from acute and chronic intensity light damage, indicated by a significant reduction in photoreceptor cell loss, and restoration of the α-transducin translocation threshold in the photoreceptors. Safety studies in the macaques demonstrated that subretinal delivery of UshStat is safe and well-tolerated. Subretinal delivery of EIAV-CMV-MYO7A (UshStat rescues photoreceptor phenotypes in the shaker1 mouse. In addition, subretinally delivered UshStat is safe and well-tolerated in macaque safety studies These data support the clinical development of UshStat to treat Usher type 1B syndrome.

EIAV-based retinal gene therapy in the shaker1 mouse model for usher syndrome type 1B: development of UshStat.

Science.gov (United States)

Zallocchi, Marisa; Binley, Katie; Lad, Yatish; Ellis, Scott; Widdowson, Peter; Iqball, Sharifah; Scripps, Vicky; Kelleher, Michelle; Loader, Julie; Miskin, James; Peng, You-Wei; Wang, Wei-Min; Cheung, Linda; Delimont, Duane; Mitrophanous, Kyriacos A; Cosgrove, Dominic

2014-01-01

Usher syndrome type 1B is a combined deaf-blindness condition caused by mutations in the MYO7A gene. Loss of functional myosin VIIa in the retinal pigment epithelia (RPE) and/or photoreceptors leads to blindness. We evaluated the impact of subretinally delivered UshStat, a recombinant EIAV-based lentiviral vector expressing human MYO7A, on photoreceptor function in the shaker1 mouse model for Usher type 1B that lacks a functional Myo7A gene. Subretinal injections of EIAV-CMV-GFP, EIAV-RK-GFP (photoreceptor specific), EIAV-CMV-MYO7A (UshStat) or EIAV-CMV-Null (control) vectors were performed in shaker1 mice. GFP and myosin VIIa expression was evaluated histologically. Photoreceptor function in EIAV-CMV-MYO7A treated eyes was determined by evaluating α-transducin translocation in photoreceptors in response to low light intensity levels, and protection from light induced photoreceptor degeneration was measured. The safety and tolerability of subretinally delivered UshStat was evaluated in macaques. Expression of GFP and myosin VIIa was confirmed in the RPE and photoreceptors in shaker1 mice following subretinal delivery of the EIAV-CMV-GFP/MYO7A vectors. The EIAV-CMV-MYO7A vector protected the shaker1 mouse photoreceptors from acute and chronic intensity light damage, indicated by a significant reduction in photoreceptor cell loss, and restoration of the α-transducin translocation threshold in the photoreceptors. Safety studies in the macaques demonstrated that subretinal delivery of UshStat is safe and well-tolerated. Subretinal delivery of EIAV-CMV-MYO7A (UshStat) rescues photoreceptor phenotypes in the shaker1 mouse. In addition, subretinally delivered UshStat is safe and well-tolerated in macaque safety studies These data support the clinical development of UshStat to treat Usher type 1B syndrome.

Liquid-Liquid Extraction in Systems Containing Butanol and Ionic Liquids – A Review

Directory of Open Access Journals (Sweden)

Kubiczek Artur

2017-03-01

Full Text Available Room-temperature ionic liquids (RTILs are a moderately new class of liquid substances that are characterized by a great variety of possible anion-cation combinations giving each of them different properties. For this reason, they have been termed as designer solvents and, as such, they are particularly promising for liquid-liquid extraction, which has been quite intensely studied over the last decade. This paper concentrates on the recent liquid-liquid extraction studies involving ionic liquids, yet focusing strictly on the separation of n-butanol from model aqueous solutions. Such research is undertaken mainly with the intention of facilitating biological butanol production, which is usually carried out through the ABE fermentation process. So far, various sorts of RTILs have been tested for this purpose while mostly ternary liquid-liquid systems have been investigated. The industrial design of liquid-liquid extraction requires prior knowledge of the state of thermodynamic equilibrium and its relation to the process parameters. Such knowledge can be obtained by performing a series of extraction experiments and employing a certain mathematical model to approximate the equilibrium. There are at least a few models available but this paper concentrates primarily on the NRTL equation, which has proven to be one of the most accurate tools for correlating experimental equilibrium data. Thus, all the presented studies have been selected based on the accepted modeling method. The reader is also shown how the NRTL equation can be used to model liquid-liquid systems containing more than three components as it has been the authors’ recent area of expertise.

Bilateral Giant Retinal Tear and Sequential Vitrectomy.

Science.gov (United States)

Mustapha, Mushawiahti; Roufail Franzco, Edward

2017-01-01

To describe the excellent outcome of surgery for bilateral giant retinal tears (GRTs) with better options of endotamponade. This is a case report of a 62-year-old man who presented with bilateral GRTs and associated retinal detachment. The tear in the right eye was supero-temporal and silicone oil was used as an endotamponade. The tear in the left eye was infero-temporal and perfluorocarbon liquid was used as an endotamponade. The outcome at 6 months after surgery was excellent with visual acuities of 6/6 in both eyes. Improved availability of endotamponade agents allows repair of bilateral GRTs to be done at the same time, with good surgical outcomes.

Liquid-liquid phase transition in Stillinger-Weber silicon

International Nuclear Information System (INIS)

Beaucage, Philippe; Mousseau, Normand

2005-01-01

It was recently demonstrated that Stillinger-Weber silicon undergoes a liquid-liquid first-order phase transition deep into the supercooled region (Sastry and Angell 2003 Nat. Mater. 2 739). Here we study the effects of perturbations on this phase transition. We show that the order of the liquid-liquid transition changes with negative pressure. We also find that the liquid-liquid transition disappears when the three-body term of the potential is strengthened by as little as 5%. This implies that the details of the potential could affect strongly the nature and even the existence of the liquid-liquid phase

Solid-Liquid and Liquid-Liquid Equilibrium in the Formamide-Acetophenone System.

Czech Academy of Sciences Publication Activity Database

Malijevská, I.; Sedláková, Zuzana; Řehák, K.; Vrbka, P.

2006-01-01

Roč. 71, 9 (2006) , s. 1350-1358 ISSN 0010-0765 Institutional research plan: CEZ:AV0Z40720504 Keywords : solid-liquid equilibria * liquid-liquid equilibria * metastable Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.881, year: 2006

Macromolecular sensing at the liquid-liquid interface

Energy Technology Data Exchange (ETDEWEB)

Herzog, Gregoire; Flynn, Shane [Tyndall National Institute, Lee Maltings, University College, Cork (Ireland); Arrigan, Damien W M, E-mail: gregoire.herzog@tyndall.ie [Nanochemistry Research Institute, Department of Chemistry, Curtin University, Perth (Australia)

2011-08-17

We report here the electrochemical sensing of macromolecules, such as polyLysine dendrimers, at the polarised liquid | liquid interface. Electrochemistry at the liquid | liquid interface is a powerful analytical technique which allows the detection of non-redox active molecules via ion transfer reactions at a polarised water - oil interface. We demonstrate here that different parameters of the polyLysine dendrimers (charge number, molecular weight) have a strong influence on the sensitivity and limit of detection of these macromolecules. This work will help to the development of sensors based on charge transfer at the liquid | liquid interface.

Macromolecular sensing at the liquid-liquid interface

International Nuclear Information System (INIS)

Herzog, Gregoire; Flynn, Shane; Arrigan, Damien W M

2011-01-01

We report here the electrochemical sensing of macromolecules, such as polyLysine dendrimers, at the polarised liquid | liquid interface. Electrochemistry at the liquid | liquid interface is a powerful analytical technique which allows the detection of non-redox active molecules via ion transfer reactions at a polarised water - oil interface. We demonstrate here that different parameters of the polyLysine dendrimers (charge number, molecular weight) have a strong influence on the sensitivity and limit of detection of these macromolecules. This work will help to the development of sensors based on charge transfer at the liquid | liquid interface.

Retinal progenitor cell xenografts to the pig retina

DEFF Research Database (Denmark)

Warfvinge, Karin; Kiilgaard, Jens Folke; Lavik, Erin B

2005-01-01

To investigate the survival, integration, and differentiation of mouse retinal progenitor cells after transplantation to the subretinal space of adult pigs.......To investigate the survival, integration, and differentiation of mouse retinal progenitor cells after transplantation to the subretinal space of adult pigs....

The competition between the liquid-liquid dewetting and the liquid-solid dewetting.

Science.gov (United States)

Xu, Lin; Shi, Tongfei; An, Lijia

2009-05-14

We investigate the dewetting behavior of the bilayer of air/PS/PMMA/silanized Si wafer and find the two competing dewetting pathways in the dewetting process. The upper layer dewets on the lower layer (dewetting pathway 1, the liquid-liquid dewetting) and the two layers rupture on the solid substrate (dewetting pathway 2, the liquid-solid dewetting). To the two competing dewetting pathways, the process of forming holes and the process of hole growth, influence their competing relation. In the process of forming holes, the time of forming holes is a main factor that influences their competing relation. During the process of hole growth, the dewetting velocity is a main factor that influences their competing relation. The liquid-liquid interfacial tension, the film thickness of the polymer, and the viscosity of the polymer are important factors that influence the time of forming holes and the dewetting velocity. When the liquid-liquid dewetting pathway and the liquid-solid dewetting pathway compete in the dewetting process, the competing relation can be controlled by changing the molecular weight of the polymer, the film thickness, and the annealing temperature. In addition, it is also found that the rim growth on the solid substrate is by a rolling mechanism in the process of hole growth.

Ternary (liquid + liquid) equilibria of {bis(trifluoromethylsulfonyl)-amide based ionic liquids + butan-1-ol + water}

International Nuclear Information System (INIS)

Marciniak, Andrzej; Wlazło, Michał; Gawkowska, Joanna

2016-01-01

Highlights: • Ternary (liquid + liquid) equilibria for 3 ionic liquid + butanol + water systems. • The influence of ionic liquid structure on phase diagrams is discussed. • Influence of IL structure on S and β for butanol/water separation is discussed. - Abstract: Ternary (liquid + liquid) phase equilibria for 3 systems containing bis(trifluoromethylsulfonyl)-amide ionic liquids (1-buthyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide, 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide, {1-(2-methoxyethyl)-1-methylpyrrolidinium bis(trifluorylsulfonyl)-amide) + butan-1-ol + water} have been determined at T = 298.15 K. The selectivity and solute distribution ratio were calculated for investigated systems and compared with literature data for other systems containing ionic liquids. In each system total solubility of butan-1-ol and low solubility of water in the ionic liquid is observed. The experimental results have been correlated using NRTL model. The influence of the structure of ionic liquid on phase equilibria, selectivity and solute distribution ratio is shortly discussed.

Retinal progenitor cell xenografts to the pig retina

DEFF Research Database (Denmark)

Warfvinge, Karin; Kiilgaard, Jens Folke; Klassen, Henry

2006-01-01

We evaluated the host response to murine retinal progenitor cells (RPCs) following transplantation to the subretinal space (SRS) of the pig. RPCs from GFP mice were transplanted subretinally in 18 nonimmunosuppressed normal or laser-treated pigs. Evaluation of the SRS was performed on hematoxylin-eosin...

Retinal pigment epithelial atrophy following indocyanine green dye-assisted surgery for serous macular detachment

Directory of Open Access Journals (Sweden)

Hussain Nazimul

2008-01-01

Full Text Available To report subretinal migration of indocyanine green dye (ICG and subsequent retinal pigment epithelial (RPE atrophy during macular surgery for serous macular detachment. A 65-year-old woman presented with residual epiretinal membrane and serous detachment of the macula following vitreoretinal surgery for epiretinal membrane. She underwent resurgery with ICG-assisted internal limiting membrane peeling and intraocular tamponade. Intraoperatively a large area of subretinal ICG was seen with subsequent RPE mottling and atrophy of the macula in the area involved during follow-up. This case demonstrates that subretinal migration of ICG is possible and can be toxic to RPE.

Use of micro-emulsions in liquid-liquid extraction

International Nuclear Information System (INIS)

Komornicki, Jacques

1982-01-01

As liquid-liquid extraction of metallic cations is an important method of separation and concentration of metals present in diluted aqueous solutions, and as the extraction rate is limited by one or several steps of matter transfer at the liquid-liquid interface, the extraction kinetics can be improved by creating a wide surface interface and by allowing an increased reactivity between species. In this research thesis, the author aims at determining to which extent systems of interface with a wide surface obtained by using for example amphiphile molecules to create micro-emulsions, can be used as reaction media for physical-chemical processes of liquid-liquid extraction. He also aims at identifying their applicability limitations and problems which might arise with their application. The author notably focuses of the liquid-liquid extraction of metallic cations exhibiting particularly slow extraction kinetics

Determination of triazine herbicides in juice samples by microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography.

Science.gov (United States)

Su, Rui; Li, Dan; Wu, Lijie; Han, Jing; Lian, Wenhui; Wang, Keren; Yang, Hongmei

2017-07-01

A novel microextraction method, termed microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction, has been developed for the rapid enrichment and analysis of triazine herbicides in fruit juice samples by high-performance liquid chromatography. Instead of using hazardous organic solvents, two kinds of ionic liquids, a hydrophobic ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) and a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), were used as the extraction solvent and dispersion agent, respectively, in this method. The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of 1-hexyl-3-methylimidazolium hexafluorophosphate dispersed entirely into sample solution with the help of 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, an ion-pairing agent (NH 4 PF 6 ) was introduced to improve recoveries of the ionic liquid phase. Several experimental parameters that might affect the extraction efficiency were investigated. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 5.00-250.00 μg/L, with the correlation coefficients of 0.9982-0.9997. The practical application of this effective and green method is demonstrated by the successful analysis of triazine herbicides in four juice samples, with satisfactory recoveries (76.7-105.7%) and relative standard deviations (lower than 6.6%). In general, this method is fast, effective, and robust to determine triazine herbicides in juice samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of metabolic gases and water vapor, perfluorocarbon emulsions, and nitric oxide on tissue bubbles during decompression sickness.

Science.gov (United States)

Randsøe, Thomas

2016-05-01

In aviation and diving, fast decrease in ambient pressure, such as during accidental loss of cabin pressure or when a diver decompresses too fast to sea level, may cause nitrogen (N2) bubble formation in blood and tissue resulting in decompression sickness (DCS). Conventional treatment of DCS is oxygen (O2) breathing combined with recompression.  However, bubble kinetic models suggest, that metabolic gases, i.e. O2 and carbon dioxide (CO2), and water vapor contribute significantly to DCS bubble volume and growth at hypobaric altitude exposures. Further, perfluorocarbon emulsions (PFC) and nitric oxide (NO) donors have, on an experimental basis, demonstrated therapeutic properties both as treatment and prophylactic intervention against DCS. The effect was ascribed to solubility of respiratory gases in PFC, plausible NO elicited nuclei demise and/or N2 washout through enhanced blood flow rate. Accordingly, by means of monitoring injected bubbles in exposed adipose tissue or measurements of spinal evoked potentials (SEPs) in anaesthetized rats, the aim of this study was to: 1) evaluate the contribution of metabolic gases and water vapor to bubble volume at different barometrical altitude exposures, 2) clarify the O2 contribution and N2 solubility from bubbles during administration of PFC at normo- and hypobaric conditions and, 3) test the effect of different NO donors on SEPs during DCS upon a hyperbaric air dive and, to study the influence of  NO on tissue bubbles at high altitude exposures. The results support the bubble kinetic models and indicate that metabolic gases and water vapor contribute significantly to bubble volume at 25 kPa (~10,376 m above sea level) and constitute a threshold for bubble stabilization or decay at the interval of 47-36 kPa (~6,036 and ~7,920 m above sea level). The effect of the metabolic gases and water vapor seemed to compromise the therapeutic properties of both PFC and NO at altitude, while PFC significantly increased bubble

The use of ultrasonic instrumentation in liquid/liquid extraction plant

International Nuclear Information System (INIS)

Asher, R.C.; Bradshaw, L.; Tolchard, A.C.

1984-01-01

Ultrasonic instruments can be used to determine many of the parameters of interest in a liquid/liquid extraction plant, eg liquid levels, the position of interfaces between immiscible liquids and the concentration of solutions. The determinations can often be made non-invasively. A number of instruments developed for a liquid/liquid extraction plant used for nuclear fuel reprocessing is described. These instruments have a wider application in liquid/liquid extraction plant in general. (author)

(Liquid + liquid), (solid + liquid), and (solid + liquid + liquid) equilibria of systems containing cyclic ether (tetrahydrofuran or 1,3-dioxolane), water, and a biological buffer MOPS

International Nuclear Information System (INIS)

Altway, Saidah; Taha, Mohamed; Lee, Ming-Jer

2015-01-01

Graphical abstract: - Highlights: • MOPS buffer induced liquid phase splitting for mixtures of water with THF or 1,3-dioxolane. • Phase boundaries of LLE, SLE, and SLLE were determined experimentally. • Tie-lines at LLE and at SLLE were also measured. • Phase diagrams of MOPS + water + THF or 1,3-dioxolane are prepared. • LLE tie-line data are correlated satisfactorily with the NRTL model. - Abstract: Two liquid phases were formed as the addition of a certain amount of biological buffer 3-(N-morpholino)propane sulfonic acid (MOPS) in the aqueous solutions of tetrahydrofuran (THF) or 1,3-dioxolane. To evaluate the feasibility of recovering the cyclic ethers from their aqueous solutions with the aid of MOPS, we determined experimentally the phase diagrams of the ternary systems of {cyclic ether (THF or 1,3-dioxolane) + water + MOPS} at T = 298.15 K under atmospheric pressure. In this study, the solubility data of MOPS in water and in the mixed solvents of water/cyclic ethers were obtained from the results of a series of density measurements, while the (liquid + liquid) and the (solid + liquid + liquid) phase boundaries were determined by visually inspection. Additionally, the tie-line results for (liquid + liquid) equilibrium (LLE) and for (solid + liquid + liquid) equilibrium (SLLE) were measured using an analytical method. The reliability of the experimental LLE tie-line results data was validated by using the Othmer–Tobias correlation. These LLE tie-line values were correlated well with the NRTL model. The phase diagrams obtained from this study reveal that MOPS is a feasible green auxiliary agent to recover the cyclic ethers from their aqueous solutions, especially for 1,3-dioxolane

Salting-out homogenous extraction followed by ionic liquid/ionic liquid liquid-liquid micro-extraction for determination of sulfonamides in blood by high performance liquid chromatography.

Science.gov (United States)

Liu, Zhongling; Yu, Wei; Zhang, Hanqi; Gu, Fanbin; Jin, Xiangqun

2016-12-01

Salting-out homogenous extraction followed by ionic liquid/ionic liquid dispersive liquid-liquid micro-extraction system was developed and applied to the extraction of sulfonamides in blood. High-performance liquid chromatography was applied to the determination of the analytes. The blood sample was centrifuged to obtain the serum. After the proteins in the serum were removed in the presence of acetonitrile, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, dipotassium hydrogen phosphate, ionic liquid 1-Hexyl-3-methylimidazolium hexafluorophosphate were added into the resulting solution. After the resulting mixture was ultrasonically shaken and centrifuged, the precipitate was separated. The acetonitrile was added in the precipitate and the analytes were extracted into the acetonitrile phase. The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of dipotassium hydrogen phosphate, volume of dispersant, extraction time and temperature were investigated. The limits of detection of sulfamethizole (STZ), sulfachlorpyridazine (SCP), sulfamethoxazole (SMX) and Sulfisoxazole (SSZ) were 4.78, 3.99, 5.21 and 3.77μgL -1 , respectively. When the present method was applied to the analysis of real blood samples, the recoveries of analytes ranged from 90.0% to 113.0% and relative standard deviations were lower than 7.2%. Copyright © 2016 Elsevier B.V. All rights reserved.

Liquid-liquid extraction of plutonium(IV) in monoamide - ammonium ionic liquid mixture

International Nuclear Information System (INIS)

Rout, Alok; Venkatesan, K.A.; Antony, M.P.

2016-01-01

Room temperature ionic liquid (RTIL) can be regarded as a sustainable alternative to the conventional molecular diluent, n-dodecane (n-DD), in solvent extraction process. Replacement of volatile organic solvents by RTILs in solvent extraction could lead to inherently safer processes. As far as the cation is concerned, most of the studies reported in literature are focused on imidazolium-based ionic liquids. In contrast to imiadazolium ionic liquids, quarternary ammonium ionic liquids like trioctylmethylammonium chloride (Aliquat 336), trioctylmethylammonium nitrate etc., do not exhibit any cation exchange with the metal ions from aqueous phase during extraction. However, there is no report available in literature that emphasizes the application of trioctylmethylammonium bis(trifluoromethane-sulfonyl)imide ((N_1_8_8_8)(NTf_2)) ionic liquid, for the extraction of Pu(IV). In this paper, we report the advantages of using the ionic liquid, trioctylmethylammonium bis(trifluoromethanesulfonyl)imide ((N_1_8_8_8)(NTf_2)), as diluent, for the extraction of plutonium(IV) in DHOA/(N_1_8_8_8)(NTf_2)

Ternary liquid-liquid equilibria for mixtures of toluene + n-heptane + an ionic liquid

NARCIS (Netherlands)

Meindersma, G.W.; Podt, J.G.; de Haan, A.B.

2006-01-01

This research has been focused on a study of sulfolane and four ionic liquids as solvents in liquid–liquid extraction. Liquid–liquid equilibria data were obtained for mixtures of (sulfolane or 4-methyl-N-butylpyridinium tetrafluoroborate ([mebupy]BF4) or 1-ethyl-3-methylimidazolium ethylsulfate

Shear viscosity of liquid argon and liquid rubidium

International Nuclear Information System (INIS)

Chiakwelu, O.

1978-01-01

A direct evaluation of the shear viscosity coefficient for models of liquid rubidium and liquid argon is presented by neglecting the cross-terms in the autocorrelation function of the transverse component of the momentum stress tensor. The time dependence of the shear viscosity for liquid argon is found to display a long decaying tail in qualitative agreement with a computer calculation of Levesque et al. However, the numerical values of the shear viscosity coefficients are smaller than the experimentally determined values of about 45% for liquid rubidium and 35% for liquid argon

Repeated subretinal surgery and removal of subretinal decalin is well tolerated

DEFF Research Database (Denmark)

Sørensen, Nina Buus; Klemp, Kristian; Kjær, Troels Wesenberg

2017-01-01

flexible tube. Two weeks after removal, a control mfERG was recorded, the pigs were enucleated and sacrificed and eyes were examined histologically. All statistics were carried out with a paired t-test in SAS Enterprise Guide 7.1® (SAS Institute Inc., Cary, NC, USA). RESULTS: There was no significant...

A comparison of conventional surfactant treatment and partial liquid ventilation on the lung volume of injured ventilated small lungs

International Nuclear Information System (INIS)

Proquitté, Hans; Hartenstein, Sebastian; Wauer, Roland R; Schmalisch, Gerd; Koelsch, Uwe; Rüdiger, Mario

2013-01-01

As an alternative to surfactant therapy (ST), partial liquid ventilation (PLV) with perfluorocarbons (PFC) has been considered as a treatment for acute lung injury (ALI) in newborns. The instilled PFC is much heavier than the instilled surfactant and the aim of this study was to investigate whether PLV, compared to ST, increases the end-expiratory volume of the lung (V L ). Fifteen newborn piglets (age <12 h, mean weight 678 g) underwent saline lung lavage to achieve a surfactant depletion. Thereafter animals were randomized to PLV (n = 8), receiving PFC PF5080 (3M, Germany) at 30 mL kg −1 , and ST (n = 7) receiving 120 mg Curosurf®. Blood gases, hemodynamics and static compliance were measured initially (baseline), immediately after ALI, and after 240 min mechanical ventilation with either technique. Subsequently all piglets were killed; the lungs were removed in toto and frozen in liquid N 2 . After freeze-drying the lungs were cut into lung cubes (LCs) with edge lengths of 0.7 cm, to calculate V L . All LCs were weighed and the density of the dried lung tissue was calculated. No statistically significant differences between treatment groups PLV and ST (means ± SD) were noted in body weight (676 ± 16 g versus 679 ± 17 g; P = 0.974) or lung dry weight (1.64 ± 0.29 g versus 1.79 ± 0.48 g; P = 0.48). Oxygenation index and ventilatory efficacy index did not differ significantly between both groups at any time. V L (34.28 ± 6.13 mL versus 26.22 ± 8.1 mL; P < 0.05) and the density of the dried lung tissue (48.07 ± 5.02 mg mL −1 versus 69.07 ± 5.30 mg mL −1 ; P < 0.001), however, differed significantly between the PLV and ST groups. A 4 h PLV treatment of injured ventilated small lungs increased V L by 30% and decreased lung density by 31% compared to ST treatment, indicating greater lung distension after PLV compared to ST. (paper)

Liquid to gas leak ratios with liquid nitrogen and liquid helium

International Nuclear Information System (INIS)

Batzer, T.H.; Call, W.R.

1985-01-01

To predict the leak rates of liquid helium and liquid nitrogen containers at operating conditions we need to know how small leaks (10 -8 to 10 -5 atm-cm 3 air/s), measured at standard conditions, behave when flooded with these cryogens. Two small leaks were measured at ambient conditions (about 750 Torr and 295 K), at the normal boiling points of LN 2 and LHe, and at elevated pressures above the liquids. The ratios of the leak rates of the liquids at ambient pressure to the gases at ambient pressure and room temperature are presented. The leak rate ratio of LN 2 at elevated pressure was linear with pressure. The leak rate ratio of LHe at elevated pressure was also linear with pressure

CASH AND LIQUIDITY/LIQUIDITY AND LIQUIDITY RATIO

OpenAIRE

ADELA BREUER; MIHAELA LESCONI FRUMUSANU; BEATRIX LIGHEZAN BREUER; ANDRA MANCIU

2012-01-01

The present paper aims to present the correlation as well as the differences between liquidity/cash and liquidity ratio in terms of economic entities. Researches on this topic are based on the opinions of some specialists in accounting and in the economic-financial analysis, as well as on the national legal stipulations and the ones set out in the International Accounting Standards, the Financial report, respectively. The object of this paper is represented by the correlation between liquidit...

Implied liquidity : towards stochastic liquidity modeling and liquidity trading

NARCIS (Netherlands)

Corcuera, J.M.; Guillaume, F.M.Y.; Madan, D.B.; Schoutens, W.

2010-01-01

In this paper we introduce the concept of implied (il)liquidity of vanilla options. Implied liquidity is based on the fundamental theory of conic finance, in which the one-price model is abandoned and replaced by a two-price model giving bid and ask prices for traded assets. The pricing is done by

Liquid--liquid contact in vapor explosion

International Nuclear Information System (INIS)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This well-known phenomenon is called a ''vapor explosion.'' One method of producing intimate, liquid--liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. In this experiment cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture). The main conclusion from the experimental study is that hydrodynamic effects may be very significant in any shock tube analyses, especially when multiple interactions are observed. A theoretical study was performed to check the possibility of vapor film squeezing (between a drop in film boiling and a surface) as a controlling mechanism for making liquid--liquid contact. Using experimental data, the film thickness was calculated and it was found to be too thick for any conceivable film rupture mechanism. It was suggested that the coalescence is a two-stage process, in which the controlling stage depends mainly on temperature and surface properties and can be described as the ability of cold liquid to spread on a hot surface

Subfoveal fibrosis in eyes with neovascular age-related macular degeneration treated with intravitreal ranibizumab

DEFF Research Database (Denmark)

Bloch, Sara Brandi; Lund-Andersen, Henrik; Sander, Birgit

2013-01-01

To assess baseline and follow-up characteristics of choroidal neovascularization (CNV) lesions in age-related macular degeneration in relation to the development of subfoveal subretinal fibrosis.......To assess baseline and follow-up characteristics of choroidal neovascularization (CNV) lesions in age-related macular degeneration in relation to the development of subfoveal subretinal fibrosis....

Liquid-liquid contact in vapor explosion

International Nuclear Information System (INIS)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials

Ionizable polyethers as specific metal ion carriers in liquid-liquid extraction and liquid membrane separations

International Nuclear Information System (INIS)

Walkowiak, W.; Charewicz, W.A.; Bartsch, R.A.; Ndip, G.M.

1988-01-01

Consideration is given to results of investigations into competitive extraction and penetration through a liquid membrane of alkali and alkaline earth cations from aqueous solutions by a series of lipophilic and ionizable acyclic polyethers of various molecular structure. It is shown that specificity and selectiviy of cation carriers in liquid-liquid extraction and liquid membrane separation depend on molecular structure of acyclic polyethers

Liquid to gas leak ratios with liquid nitrogen and liquid helium

International Nuclear Information System (INIS)

Batzer, T.H.; Call, W.R.

1985-01-01

To predict the leak rates of liquid helium and liquid nitrogen containers at operating conditions we need to know how small leaks (10 -8 to 10 -5 atm-cm 3 air/s), measured at standard conditions, behave when flooded with these cryogens. Two small leaks were measured at ambient conditions (approx.750 Torr and 295 K), at the normal boiling points of LN 2 and LHe, and at elevated pressures above the liquids. The ratios of the leak rates of the liquids at ambient pressure to the gases (G) at ambient pressure and room temperature were: GN 2 (1), LN 2 (18), GHe(1), and LHe(172). The leak rate ratio of LN 2 at elevated pressure was linear with pressure. The leak rate ratio of LHe at elevated pressure was also linear with pressure

Metastable liquid-liquid transition in a molecular model of water

Science.gov (United States)

Palmer, Jeremy C.; Martelli, Fausto; Liu, Yang; Car, Roberto; Panagiotopoulos, Athanassios Z.; Debenedetti, Pablo G.

2014-06-01

Liquid water's isothermal compressibility and isobaric heat capacity, and the magnitude of its thermal expansion coefficient, increase sharply on cooling below the equilibrium freezing point. Many experimental, theoretical and computational studies have sought to understand the molecular origin and implications of this anomalous behaviour. Of the different theoretical scenarios put forward, one posits the existence of a first-order phase transition that involves two forms of liquid water and terminates at a critical point located at deeply supercooled conditions. Some experimental evidence is consistent with this hypothesis, but no definitive proof of a liquid-liquid transition in water has been obtained to date: rapid ice crystallization has so far prevented decisive measurements on deeply supercooled water, although this challenge has been overcome recently. Computer simulations are therefore crucial for exploring water's structure and behaviour in this regime, and have shown that some water models exhibit liquid-liquid transitions and others do not. However, recent work has argued that the liquid-liquid transition has been mistakenly interpreted, and is in fact a liquid-crystal transition in all atomistic models of water. Here we show, by studying the liquid-liquid transition in the ST2 model of water with the use of six advanced sampling methods to compute the free-energy surface, that two metastable liquid phases and a stable crystal phase exist at the same deeply supercooled thermodynamic condition, and that the transition between the two liquids satisfies the thermodynamic criteria of a first-order transition. We follow the rearrangement of water's coordination shell and topological ring structure along a thermodynamically reversible path from the low-density liquid to cubic ice. We also show that the system fluctuates freely between the two liquid phases rather than crystallizing. These findings provide unambiguous evidence for a liquid-liquid transition in

Liquidity constraints, risk premia, and themacroeconomic effects of liquidity shocks

OpenAIRE

Jaccard, Ivan

2013-01-01

We study the transmission of liquidity shocks in a dynamic general equilibrium model where firms and households are subject to liquidity risk. The provision of liquidity services is undertaken by financial intermediaries that allocate the stock of liquid asset between the different sectors of the economy. We find that the macroeconomic effects of liquidity shocks are considerably larger in the model economy that generates a realistic equity premium. Liquidity constraints amplify business cycl...

Banks’ liquidity buffers and the role of liquidity regulation

OpenAIRE

Zymek, Robert; van Lelyveld, Iman; Bonner, Clemens

2015-01-01

We assess the determinants of banks' liquidity holdings using balance sheet data for nearly 7000 banks from 30 OECD countries over a ten-year period. We highlight the role of several bank-specific, institutional and policy variables in shaping banks' liquidity risk management. Our main question is whether the presence of liquidity regulation substitutes or complements banks' incentives to hold liquid assets. Our results reveal that in the absence of liquidity regulation, the determinants of b...

Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

Science.gov (United States)

Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

2015-01-01

Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

A technical review of liquid/liquid and solid/liquid separation equipment in the field of nuclear-fuel reprocessing

International Nuclear Information System (INIS)

Vassallo, G.

1981-01-01

Liquid/liquid extraction is generally accepted as the preferred method in nuclear-fuel reprocessing. However, although many types of liquid/liquid contactors are available, only a few meet the stringent specifications set by the nuclear industry. This report discusses the criteria for contactor selection and then reviews the most important types, namely packed columns, pulsed columns, mixer-setters and centrifugal contactors. Finally, a short section concerned with solid/liquid separations is included because of the possible deleterious effects caused by solids in liquid/liquid contactors

Drusen Characterization with Multimodal Imaging

Science.gov (United States)

Spaide, Richard F.; Curcio, Christine A.

2010-01-01

Summary Multimodal imaging findings and histological demonstration of soft drusen, cuticular drusen, and subretinal drusenoid deposits provided information used to develop a model explaining their imaging characteristics. Purpose To characterize the known appearance of cuticular drusen, subretinal drusenoid deposits (reticular pseudodrusen), and soft drusen as revealed by multimodal fundus imaging; to create an explanatory model that accounts for these observations. Methods Reported color, fluorescein angiographic, autofluorescence, and spectral domain optical coherence tomography (SD-OCT) images of patients with cuticular drusen, soft drusen, and subretinal drusenoid deposits were reviewed, as were actual images from affected eyes. Representative histological sections were examined. The geometry, location, and imaging characteristics of these lesions were evaluated. A hypothesis based on the Beer-Lambert Law of light absorption was generated to fit these observations. Results Cuticular drusen appear as numerous uniform round yellow-white punctate accumulations under the retinal pigment epithelium (RPE). Soft drusen are larger yellow-white dome-shaped mounds of deposit under the RPE. Subretinal drusenoid deposits are polymorphous light-grey interconnected accumulations above the RPE. Based on the model, both cuticular and soft drusen appear yellow due to the removal of shorter wavelength light by a double pass through the RPE. Subretinal drusenoid deposits, which are located on the RPE, are not subjected to short wavelength attenuation and therefore are more prominent when viewed with blue light. The location and morphology of extracellular material in relationship to the RPE, and associated changes to RPE morphology and pigmentation, appeared to be primary determinants of druse appearance in different imaging modalities. Conclusion Although cuticular drusen, subretinal drusenoid deposits, and soft drusen are composed of common components, they are distinguishable

Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.

Science.gov (United States)

Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

2014-11-01

An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dynamics of solid nanoparticles near a liquid-liquid interface

Science.gov (United States)

Daher, Ali; Ammar, Amine; Hijazi, Abbas

2018-05-01

The liquid - liquid interface can be used as a suitable medium for generating some nanostructured films of metals, or inorganic materials such as semi conducting metals. This process can be controlled well if we study the dynamics of nanoparticles (NPs) at the liquid-liquid interface which is a new field of study, and is not understood well yet. The dynamics of NPs at liquid-liquid interfaces is investigated by solving the fluid-particle and particle-particle interactions. Our work is based on the Molecular Dynamics (MD) simulation in addition to Phase Field (PF) method. We modeled the liquid-liquid interface using the diffuse interface model, where the interface is considered to have a characteristic thickness. We have shown that the concentration gradient of one fluid in the other gives rise to a hydrodynamic force that drives the NPs to agglomerate at the interface. These obtained results may introduce new applications where certain interfaces can be considered to be suitable mediums for the synthesis of nanostructured materials. In addition, some liquid interfaces can play the role of effective filters for different species of biological NPs and solid state waste NPs, which will be very important in many industrial and biomedical domains.

Plasma-liquid system with rotational gliding discharge with liquid electrode

International Nuclear Information System (INIS)

Nedybaliuk, O.A.; Solomenko, O.V; Martysh, E.V.; Fedirchuk, I.I.

2014-01-01

Plasma-liquid system based on rotational gliding discharge with one liquid electrode was developed. Emission spectra of plasma of rotational gliding discharge with one liquid electrode were investigated. Discovered effective mechanism of controlling non-isothermal level of plasma in dynamic plasma-liquid systems. Major mechanism of expulsion of metal anode material from plasma-liquid systems with rotational discharges was shown.

Liquid scintillation spectrometer survey 155Eu liquid activity

International Nuclear Information System (INIS)

Zhang Zuhua

2002-01-01

In the countrywide contrasting survey of 155 Eu activity, 155 Eu liquid activity was determined for the first time through using liquid scintillation spectrometer survey 155 Eu β ray. In survey total uncertainty, determining activity accord with determining activity average value of all a wide variety of survey instrument entering into contrasting survey. But using liquid scintillation spectrometer survey, it is simple and save time, is beyond compare for other survey method. It indicate liquid scintillation spectrometer survey β-γ nuclide activity is effective as well

Static gas-liquid interfacial direct current discharge plasmas using ionic liquid cathode

International Nuclear Information System (INIS)

Kaneko, T.; Baba, K.; Hatakeyama, R.

2009-01-01

Due to the unique properties of ionic liquids such as their extremely low vapor pressure and high heat capacity, we have succeeded in creating the static and stable gas (plasmas)-liquid (ionic liquids) interfacial field using a direct current discharge under a low gas pressure condition. It is clarified that the ionic liquid works as a nonmetal liquid electrode, and furthermore, a secondary electron emission coefficient of the ionic liquid is larger than that of conventional metal electrodes. The plasma potential structure of the gas-liquid interfacial region, and resultant interactions between the plasma and the ionic liquid are revealed by changing a polarity of the electrode in the ionic liquid. By utilizing the ionic liquid as a cathode electrode, the positive ions in the plasma region are found to be irradiated to the ionic liquid. This ion irradiation causes physical and chemical reactions at the gas-liquid interfacial region without the vaporization of the ionic liquid.

Active liquid/liquid interfaces: contributions of non linear optics and tensiometry

International Nuclear Information System (INIS)

Gassin, P.M.

2013-01-01

Liquid-liquid extraction processes are widely used in the industrial fields of selective separation. Despite its numerous applications, the microscopic mechanisms which occur during a liquid-liquid extraction processes are really unknown specially at the liquid/liquid interface. Thus, this work deals on the understanding of the phenomena which drive the mass transfer across a liquid/liquid interface. Two experimental techniques were used in this work: dynamic interfacial tension measurement and non-linear optical experiments. Along with the use of this experimental approach, a numerical model describing the mass transfer dynamic has been developed. This model works under the assumption that both diffusion and a chemical step describing adsorption and desorption processes contribute to the global transfer kinetics. Model systems of surfactant molecules, chromophore molecules and complexing molecule were investigated at liquid/liquid and air/liquid interface. Interfacial phenomena like adsorption, surface aggregation and ion complexing were studied. Finally, the methodology developed in this work was applied to studied an extractant molecule with potential industrial application. (author) [fr

Vitrification and levitation of a liquid droplet on liquid nitrogen

OpenAIRE

Song, Young S.; Adler, Douglas; Xu, Feng; Kayaalp, Emre; Nureddin, Aida; Anchan, Raymond M.; Maas, Richard L.; Demirci, Utkan

2010-01-01

The vitrification of a liquid occurs when ice crystal formation is prevented in the cryogenic environment through ultrarapid cooling. In general, vitrification entails a large temperature difference between the liquid and its surrounding medium. In our droplet vitrification experiments, we observed that such vitrification events are accompanied by a Leidenfrost phenomenon, which impedes the heat transfer to cool the liquid, when the liquid droplet comes into direct contact with liquid nitroge...

Structural analysis of zwitterionic liquids vs. homologous ionic liquids

Science.gov (United States)

Wu, Boning; Kuroda, Kosuke; Takahashi, Kenji; Castner, Edward W.

2018-05-01

Zwitterionic liquids (Zw-ILs) have been developed that are homologous to monovalent ionic liquids (ILs) and show great promise for controlled dissolution of cellulosic biomass. Using both high energy X-ray scattering and atomistic molecular simulations, this article compares the bulk liquid structural properties for novel Zw-ILs with their homologous ILs. It is shown that the significant localization of the charges on Zw-ILs leads to charge ordering similar to that observed for conventional ionic liquids with monovalent anions and cations. A low-intensity first sharp diffraction peak in the liquid structure factor S(q) is observed for both the Zw-IL and the IL. This is unexpected since both the Zw-IL and IL have a 2-(2-methoxyethoxy)ethyl (diether) functional group on the cationic imidazolium ring and ether functional groups are known to suppress this peak. Detailed analyses show that this intermediate range order in the liquid structure arises for slightly different reasons in the Zw-IL vs. the IL. For the Zw-IL, the ether tails in the liquid are shown to aggregate into nanoscale domains.

Viscous effects in liquid encapsulated liquid bridges

International Nuclear Information System (INIS)

Johnson, Duane T.

2002-01-01

An analytical derivation of the surface deflections and the streamfunctions for the flow inside a liquid encapsulated liquid bridge has been derived using an asymptotic expansion about a small capillary number. The model assumes an initially flat and cylindrical interface under the assumption that the densities of both fluids are equal. To simplify the analysis, the top and bottom walls are assumed to be stress-free and the Reynolds number is assumed to be negligible. Flow is generated either by a moving outer wall (shear-driven flow) or by applying a temperature difference across the top and bottom walls (Marangoni-driven flow). The resulting equations show that for the shear-driven flow, as the viscosity ratio increases, the surface deflections increase monotonically. For the Marangoni-driven flow there exist values of the viscosity ratio where the surface deflections reach a minimum and then switch signs. This investigation shows that it may be possible in more realistic systems to use an outer encapsulating liquid of the proper viscosity ratio to stabilize the liquid-liquid interface during float zone crystal growth

Evaporation of a liquid drop on a hot liquid surface, (1)

International Nuclear Information System (INIS)

Iida, Yoshihiro; Takashima, Takeo

1980-01-01

As for the phenomena occurring when two kinds of liquid at different temperature come in contact, the clarification of the basic, general matters of the phenomena has not been made yet. Such situation has been caused by the facts that the detailed observation of the aspect in liquid-liquid contact becomes impossible as the disturbance on the interface becomes violent, and it is difficult to obtain the quantitative data and to change temperature difference largely in practice. In this study, liquid drops were dropped on the free surface of another liquid at the temperature higher than the saturation temperature of the dropping liquid, and it was attempted to obtain the basic knowledge concerning the general behavior at the time of liquid-liquid contact by determining the aspect of evaporation and its change and evaporation time. For this experiment, the silicone oil with four different kinematic viscosity was used as the high temperature liquid, and n-pentane and dichloromethane soluble in the mother liquid, and acetone and methyl alcohol insoluble in the mother liquid were used as the liquid drops. The experimental apparatuses and method and the results are reported. The evaporation time curves presented lying S-shape basically, similarly to the evaporation on solid surfaces. The point of maximum evaporation time and the point of maximum heat transfer rate existed. (J.P.N.)

Fundus autofluorescence in central serous chorioretinopathy:association with spectral-domain optical coherence tomography and fluorescein angiography

Directory of Open Access Journals (Sweden)

Peng Zhang

2015-10-01

Full Text Available AIM: To evaluate the correlation among changes in fundus autofluorescence (AF measured using infrared fundus AF (IR-AF and short-wave length fundus AF (SW-AF with changes in spectral-domain optical coherence tomography (SD-OCT and fluorescein angiography (FA in central serous chorioretinopathy (CSC.METHODS:Two hundred and twenty consecutive patients with CSC were included. In addition to AF, patients were assessed by means of SD-OCT and FA. Abnormalities in images of IR-AF, SW-AF, FA were analyzed and correlated with the corresponding outer retinal alterations in SD-OCT findings.RESULTS:Eyes with abnormalities on either IR-AF or SW-AF were found in 256 eyes (58.18%, among them 256 eyes (100% showed abnormal IR-AF, but SW-AF abnormalities were present only in 213 eyes (83.20%. The hypo-IR-AF corresponded to accumulation of sub-retinal liquid, collapse of retinal pigment epithelium (RPE or detachment of RPE with or without RPE leakage point in the corresponding area. The hyper-IR-AF corresponded to the area with loss of the ellipsoid portion of the inner segments and sub-sensory retinal deposits or focal melanogenesis under sensory retina. The hypo-SW-AF corresponded to accumulation of sub-retinal liquid or atrophy of RPE. The hyper-SW-AF associated with sub-sensory retinal deposits, detachment of RPE and focal melanogenesis.CONCLUSION:IR-AF was more sensitive than SW-AF and FA for identifying pathological abnormalities in CSC. The characteristics of IR-AF in CSC were attributable to the modification of melanin in the RPE. IR-AF should be used as a common diagnostic tool for identifying pathological lesion in CSC.KEYWORDS:central serous chorioretinopathy; fluorescein angiography; fundus autofluorescence; optical coherence tomography

Vitrification and levitation of a liquid droplet on liquid nitrogen.

Science.gov (United States)

Song, Young S; Adler, Douglas; Xu, Feng; Kayaalp, Emre; Nureddin, Aida; Anchan, Raymond M; Maas, Richard L; Demirci, Utkan

2010-03-09

The vitrification of a liquid occurs when ice crystal formation is prevented in the cryogenic environment through ultrarapid cooling. In general, vitrification entails a large temperature difference between the liquid and its surrounding medium. In our droplet vitrification experiments, we observed that such vitrification events are accompanied by a Leidenfrost phenomenon, which impedes the heat transfer to cool the liquid, when the liquid droplet comes into direct contact with liquid nitrogen. This is distinct from the more generally observed Leidenfrost phenomenon that occurs when a liquid droplet is self-vaporized on a hot plate. In the case of rapid cooling, the phase transition from liquid to vitrified solid (i.e., vitrification) and the levitation of droplets on liquid nitrogen (i.e., Leidenfrost phenomenon) take place simultaneously. Here, we investigate these two simultaneous physical events by using a theoretical model containing three dimensionless parameters (i.e., Stefan, Biot, and Fourier numbers). We explain theoretically and observe experimentally a threshold droplet radius during the vitrification of a cryoprotectant droplet in the presence of the Leidenfrost effect.

Liquid-liquid interfacial tension of electrolyte solutions

OpenAIRE

Bier, Markus; Zwanikken, Jos; van Roij, Rene

2008-01-01

It is theoretically shown that the excess liquid-liquid interfacial tension between two electrolyte solutions as a function of the ionic strength I behaves asymptotically as O(- I^0.5) for small I and as O(+- I) for large I. The former regime is dominated by the electrostatic potential due to an unequal partitioning of ions between the two liquids whereas the latter regime is related to a finite interfacial thickness. The crossover between the two asymptotic regimes depends sensitively on mat...

Liquid-liquid contact in vapor explosion. [LMFBR

Energy Technology Data Exchange (ETDEWEB)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture).

Spontaneous Marangoni Mixing of Miscible Liquids at a Liquid-Liquid-Air Contact Line.

Science.gov (United States)

Kim, Hyoungsoo; Lee, Jeongsu; Kim, Tae-Hong; Kim, Ho-Young

2015-08-11

We investigate the flow patterns created when a liquid drop contacts a reservoir liquid, which has implications on various physicochemical and biochemical reactions including mixing in microfluidic systems. The localized vortical flow spontaneously triggered by the difference of surface tension between the two liquids is studied, which is thus termed the Marangoni vortex. To quantitatively investigate the strength of vortices, we performed particle image velocimetry (PIV) experiments by varying the surface tension difference, the gap of the flow cell, the density and viscosity of the reservoir liquid, and the size of the drop. A scaling law that balances the interfacial energy of the system with the kinetic energy of the vortical flows allows us to understand the functional dependence of the Marangoni vortex strength on various experimental parameters.

Liquid-liquid and liquid-solid phase separation and flocculation for a charged colloidal dispersion

International Nuclear Information System (INIS)

Lai, S.K.; Wu, K.L.

2002-01-01

We model the intercolloidal interaction by a hard-sphere Yukawa repulsion to which is added the long-range van der Waals attraction. In comparison with the Derjaguin-Landau-Verwey-Overbeek repulsion, the Yukawa repulsion explicitly incorporates the spatial correlations between colloids and small ions. As a result, the repulsive part can be expressed analytically and has a coupling strength depending on the colloidal volume fraction. By use of this two-body potential of mean force and in conjunction with a second-order thermodynamic perturbation theory, we construct the colloidal Helmholtz free energy and use it to calculate the thermodynamic quantities, pressure and chemical potential, needed in the determination of the liquid-liquid and liquid-solid phase diagrams. We examine, in an aqueous charged colloidal dispersion, the effects of the Hamaker constant and particle size on the conformation of a stable liquid-liquid phase transition calculated with respect to the liquid-solid coexistence phases. We find that there exists a threshold Hamaker constant or particle size whose value demarcates the stable liquid-liquid coexistence phases from their metastable counterparts. Applying the same technique and using the energetic criterion, we extend our calculations to study the flocculation phenomenon in aqueous charged colloids. Here, we pay due attention to determining the loci of a stability curve stipulated for a given temperature T 0 , and obtain the parametric phase diagram of the Hamaker constant vs the coupling strength or, at given surface potential, the particle size. By imposing T 0 to be the critical temperature T c , i.e., setting k B T 0 (=k B T c ) equal to a reasonable potential barrier, we arrive at the stability curve that marks the irreversible reversible phase transition. The interesting result is that there occurs a minimum size for the colloidal particles below (above) which the colloidal dispersion is driven to an irreversible (reversible) phase

Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

Science.gov (United States)

Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-01-01

A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

Flat choroidal melanoma masquerading as central serous chorioretinopathy

Directory of Open Access Journals (Sweden)

Timothy Patrick Higgins

2016-01-01

Full Text Available There are several mimickers of choroidal melanoma. We report a patient with recent family stress who developed blurred vision to 20/50 OD and was found to have unilateral central serous chorioretinopathy and a coincidental choroidal nevus. After 1 year without resolution of the subretinal fluid, the patient was referred for our opinion. On examination, visual acuity was 20/50 in the right eye and 20/20 in the left eye. The left eye was normal. Evaluation of the right eye showed a small, pigmented submacular choroidal lesion measuring 4 mm Χ 3 mm. Ultrasonography documented an isoechoic mass measuring 1.71 mm in thickness. Optical coherence tomography showed subretinal fluid with shaggy photoreceptors and hyper-reflective material within the subretinal fluid, likely indicative of lipofuscin within macrophages. Autofluorescence revealed orange pigment overlying the lesion. These features were strongly suggestive of small choroidal melanoma with five risk factors for tumor growth. Treatment with Iodine-125 plaque brachytherapy was performed on the patient. The readers should keep in mind that choroidal melanoma can manifest as a tiny choroidal mass with related multimodal imaging features of subretinal fluid and orange pigment.

Toxicological evaluation of liquids proposed for use in direct contact liquid--liquid heat exchangers for solar heated and cooled buildings

Energy Technology Data Exchange (ETDEWEB)

Buchan, R.M.; Majestic, J.R.; Billau, R.

1976-09-01

This report contains the results of the toxicological evaluation part of the project entitled, ''Direct Contact Liquid-Liquid Heat Exchangers for Solar Heated and Cooled Buildings.'' Obviously any liquid otherwise suitable for use in such a device should be subjected to a toxicological evaluation. 34 liquids (24 denser than water, 10 less dense) have physical and chemical properties that would make them suitable for use in such a device. In addition to the complexity involved in selecting the most promising liquids from the standpoint of their chemical and physical properties is added the additional difficulty of also considering their toxicological properties. Some of the physical and chemical properties of these liquids are listed. The liquids are listed in alphabetical order within groups, the denser than water liquids are listed first followed by those liquids less dense than water.

Liquid Wall Chambers

Energy Technology Data Exchange (ETDEWEB)

Meier, W R

2011-02-24

The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

Funding liquidity, market liquidity and TED spread : A two-regime model

NARCIS (Netherlands)

Boudt, Kris; Paulus, Ellen C.S.; Rosenthal, Dale W.R.

2017-01-01

We study the effect of market liquidity on equity-collateralized funding, accounting for endogeneity. Theory suggests market liquidity can affect funding liquidity in stabilizing and destabilizing manners. Using a new proxy for equity-collateralized funding liquidity of S&P 500 stocks over the

A review of solid-fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid-liquid and multiphase solid-liquid flows

Science.gov (United States)

Wright, Stuart F.; Zadrazil, Ivan; Markides, Christos N.

2017-09-01

Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid-liquid and solid-liquid-liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid-liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330-1.620 and 1.251-1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid-liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity.

CATION-EXCHANGE SOLID-PHASE AND LIQUID-LIQUID ...

African Journals Online (AJOL)

B. S. Chandravanshi

An existing liquid-liquid extraction (LLE) method was improved in terms of ... clean-up of the alkaloids from khat leaves, prior to HPLC-DAD detection. Despite .... The limits of detection (LOD) and quantification (LOQ) were calculated using the.

Acceleration of liquid by boiling of other volatile liquid, (4)

International Nuclear Information System (INIS)

Hijikata, Kunio; Mori, Yasuo

1978-01-01

In the development of liquid metal MHD power generation using liquid metal as a working fluid, it is one of the important problems to accelerate liquid metal efficiently by means of thermal energy. Though various accelerating methods have been proposed so far, those do not provide high cycle thermal efficiency because of either small electric conductivity, low accelerating efficiency or low gas-liquid separating efficiency. The authors proposed the method to accelerate through volume expansion by boiling a volatile liquid being blown into liquid metal at high temperature, and have investigated it experimentally and theoretically. In the study, efficiency has been discussed in case of the acceleration of fluid subjected to magneto-hydrodynamical force by boiling of droplets of other liquid. Theoretically, the field of flow and two-phase cycle and gas phase cycle were analyzed. The report describes on these results and discussions. It is concluded that efficiency is independent of the injected amount and position of droplets, final efficiency is little affected by external load and thermal conductivity of volatile liquid droplets, the efficiency for the combination of cesium and lead is about 50%, and the method proposed by authors seems to be better than the conventional methods with gas phase cycle proposed so far using inert gas bubbles in lieu of volatile liquid. (Wakatsuki, Y.)

Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology.

Science.gov (United States)

Brown, Leslie; Earle, Martyn J; Gîlea, Manuela A; Plechkova, Natalia V; Seddon, Kenneth R

2017-08-10

Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

Recent development of ionic liquid stationary phases for liquid chromatography.

Science.gov (United States)

Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

2015-11-13

Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years. Copyright © 2015 Elsevier B.V. All rights reserved.

Separation of Asphaltenes by Polarity using Liquid-Liquid Extraction

DEFF Research Database (Denmark)

Andersen, Simon Ivar

1997-01-01

In order to investigate the nature of petroleum asphaltenes in terms of polarity a process was developed using initial liquid-liquid extraction of the oil phase followed by precipitation of the asphaltenes using n-heptane. The liquid-liquid extraction was performed using toluene-methanol mixtures...... phase. The asphaltenes were analysed using FTir, Elemental analysis, and HPLC-SEC with a diode array detector. With increasing content of toluene in the methanol the molecular weight distribution of the asphaltenes significantly move to higher molecular weights. The content of nitrogen and sulfur...

Structural crossover in a supercooled metallic liquid and the link to a liquid-to-liquid phase transition

Energy Technology Data Exchange (ETDEWEB)

Lan, S.; Ma, J. L.; Fan, J. [Department of Physics and Material Science, City University of Hong Kong 83 Tat Chee Ave., Kowloon (Hong Kong); Blodgett, M.; Kelton, K. F. [Department of Physics and Institute of Materials Science and Engineering, Washington University One Brookings Drive, St. Louis, Missouri 63130-4899 (United States); Wang, X.-L., E-mail: xlwang@cityu.edu.hk [Department of Physics and Material Science, City University of Hong Kong 83 Tat Chee Ave., Kowloon (Hong Kong); City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057 (China)

2016-05-23

Time-resolved synchrotron measurements were carried out to capture the structure evolution of an electrostatically levitated metallic-glass-forming liquid during free cooling. The experimental data shows a crossover in the liquid structure at ∼1000 K, about 115 K below the melting temperature and 150 K above the crystallization temperature. The structure change is characterized by a dramatic growth in the extended-range order below the crossover temperature. Molecular dynamics simulations have identified that the growth of the extended-range order was due to an increased correlation between solute atoms. These results provide structural evidence for a liquid-to-liquid-phase-transition in the supercooled metallic liquid.

Liquid waste sampling device

International Nuclear Information System (INIS)

Kosuge, Tadashi

1998-01-01

A liquid pumping pressure regulator is disposed on the midway of a pressure control tube which connects the upper portion of a sampling pot and the upper portion of a liquid waste storage vessel. With such a constitution, when the pressure in the sampling pot is made negative, and liquid wastes are sucked to the liquid pumping tube passing through the sampling pot, the difference between the pressure on the entrance of the liquid pumping pressure regulator of the pressure regulating tube and the pressure at the bottom of the liquid waste storage vessel is made constant. An opening degree controlling meter is disposed to control the degree of opening of a pressure regulating valve for sending actuation pressurized air to the liquid pumping pressure regulator. Accordingly, even if the liquid level of liquid wastes in the liquid waste storage vessel is changed, the height for the suction of the liquid wastes in the liquid pumping tube can be kept constant. With such procedures, sampling can be conducted correctly, and the discharge of the liquid wastes to the outside can be prevented. (T.M.)

The Association between Plasma 25-Hydroxyvitamin D and Subgroups in Age-Related Macular Degeneration

DEFF Research Database (Denmark)

Singh, Amardeep; Falk, Mads Krüger; Subhi, Yousif

2013-01-01

To evaluate potential differences in plasma 25-hydroxyvitamin in subtypes of age-related macular degeneration (AMD), and in patients in Clinical Age-Related Maculopathy Staging (CARMS) group 5 with or without subretinal fibrosis.......To evaluate potential differences in plasma 25-hydroxyvitamin in subtypes of age-related macular degeneration (AMD), and in patients in Clinical Age-Related Maculopathy Staging (CARMS) group 5 with or without subretinal fibrosis....

Acidic Ionic Liquids.

Science.gov (United States)

Amarasekara, Ananda S

2016-05-25

Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

Subsidizing Liquidity

DEFF Research Database (Denmark)

Malinova, Katya; Park, Andreas

2015-01-01

the breakdown of trading fees between liquidity demanders and suppliers matters. Posted quotes adjust after the change in fee composition, but the transaction costs for liquidity demanders remain unaffected once fees are taken into account. However, as posted bid-ask spreads decline, traders (particularly......Facing increased competition over the last decade, many stock exchanges changed their trading fees to maker-taker pricing, an incentive scheme that rewards liquidity suppliers and charges liquidity demanders. Using a change in trading fees on the Toronto Stock Exchange, we study whether and why...... retail) use aggressive orders more frequently, and adverse selection costs decrease....

Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology

OpenAIRE

Brown, Leslie; Earle, Martyn J; Gilea, Manuela; Plechkova, Natalia V; Seddon, Kenneth R

2017-01-01

Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous char...

Dry powder dosing in liquid vehicles: ocular tolerance and scintigraphic evaluation of a perfluorocarbon suspension.

Science.gov (United States)

Zhu, Y; Wilson, C G; Meadows, D; Olejnik, O; Frier, M; Washington, N; Musson, R

1999-11-30

The ocular tolerance and precorneal disposition of 99mTc-labelled sterile carbon-perfluorodecalin (PFD) and carbon-aqueous suspensions were examined in a cohort of healthy volunteers. Formulations were prepared in PFD or saline using charcoal particles, radiolabelled with [99mTc]diethylenetriaminepentaacetic acid (DTPA) under GMP conditions. Colloidal silicon dioxide was used as a suspending agent. Ocular tolerance was examined following the instillation of each formulation to the eyes of 12 volunteers. The precorneal distribution of both formulations in man was monitored using gamma scintigraphy. Dynamic and static data acquisitions were taken over a period of 150 min after dosing. Carbon particulates suspended in PFD did not show any irritation to the eye. Administration of PFD formulation in man produced a significant increase in ocular retention over a saline formulation (mean residence time (MRT)=157+/-42 and 0.29+/-0.08 min, respectively, P=0.0001). Distribution of the carbon in man followed the same pattern as in a previous reported study in animals. The carbon deposited uniformly along the lid margin in the case of the PFD vehicle, whereas it agglomerated following dosing in the saline vehicle and was ejected from the eye. The novel non-aqueous vehicle system is able to significantly improve the ocular retention of charcoal particles in man and provides a unique distribution of the particles in the eye, which suggests a potential for the PFD system for the treatment of periocular diseases.

Nanoparticles in liquid crystals, and liquid crystals in nanoparticles

Science.gov (United States)

de Pablo, Juan

2015-03-01

Liquid crystals are remarkably sensitive to interfacial interactions. Small perturbations at a liquid crystal interface, for example, can be propagated over relatively long length scales, thereby providing the basis for a wide range of applications that rely on amplification of molecular events into macroscopic observables. Our recent research efforts have focused on the reverse phenomenon; that is, we have sought to manipulate the interfacial assembly of nanoparticles or the organization of surface active molecules by controlling the structure of a liquid crystal. This presentation will consist of a review of the basic principles that are responsible for liquid crystal-mediated interactions, followed by demonstrations of those principles in the context of two types of systems. In the first, a liquid crystal is used to direct the assembly of nanoparticles; through a combination of molecular and continuum models, it is found that minute changes in interfacial energy and particle size lead to liquid-crystal induced attractions that can span multiple orders of magnitude. Theoretical predictions are confirmed by experimental observations, which also suggest that LC-mediated assembly provides an effective means for fabrication of plasmonic devices. In the second type of system, the structure of a liquid crystal is controlled by confinement in submicron droplets. The morphology of the liquid crystal in a drop depends on a delicate balance between bulk and interfacial contributions to the free energy; that balance can be easily perturbed by adsorption of analytes or nanoparticles at the interface, thereby providing the basis for development of hierarchical assembly of responsive, anisotropic materials. Theoretical predictions also indicate that the three-dimensional order of a liquid crystal can be projected onto a two-dimensional interface, and give rise to novel nanostructures that are not found in simple isotropic fluids.

Transuranium element purification by liquid-liquid extraction

International Nuclear Information System (INIS)

Madic, C.; Koehly, G.

1976-01-01

In the transuranium element production, the liquid-liquid extraction purification is presented. The affinity of TBP and trilaurylammonium nitrate for these elements is given. Exemples of NP/Pu, Pu/Np, U/Pu, Am/Cm, Am and Cm/Ln separation are presented [fr

Experimental evidence of a liquid-liquid transition in interfacial water

Science.gov (United States)

Zanotti, J.-M.; Bellissent-Funel, M.-C.; Chen, S.-H.

2005-07-01

At ambient pressure, bulk liquid water shows an anomalous increase of thermodynamic quantities and apparent divergences of dynamic properties on approaching a temperature Ts of 228 K. At normal pressure, supercooled water spontaneously freezes below the homogeneous nucleation temperature, TH = 235 K. Upon heating, the two forms of Amorphous Solid Water (ASW), LDA (Low Density Amorphous Ice) and HDA (High Density Amorphous Ice), crystallise above TX = 150 K. As a consequence, up to now no experiment has been able to explore the properties of liquid water in this very interesting temperature range between 150 and 235 K. We present nanosecond-time-scale measurements of local rotational and translational dynamics of interfacial, non-crystalline, water from 77 to 280 K. These experimental dynamic results are combined with calorimetric and diffraction data to show that after exhibiting a glass transition at 165 K, interfacial water experiences a first-order liquid-liquid transition at 240 K from a low-density to a high-density liquid. This is the first direct evidence of the existence of a liquid-liquid transition involving water.

Acidic ionic liquids for n-alkane isomerization in a liquid-liquid or slurry-phase reaction mode

Energy Technology Data Exchange (ETDEWEB)

Meyer, C.; Hager, V.; Geburtig, D.; Kohr, C.; Wasserscheid, P. [Erlangen-Nuernberg Univ. (Germany). Lehrstuhl fuer Chemische Reaktionstechnik; Haumann, M. [Chemical Reaction Engineering, FAU Busan Campus, Korea (Korea, Republic of)

2011-07-01

Highly acidic ionic liquid (IL) catalysts offer the opportunity to convert n-alkanes at very low reaction temperatures. The results of IL catalyzed isomerization and cracking reactions of pure n-octane are presented. Influence of IL composition, [C{sub 4}C{sub 1}Im]Cl / AlCl{sub 3} / H{sub 2}SO{sub 4} and [C{sub 4}C{sub 1}Im]Cl / AlCl{sub 3} / 1-chlorooctane, on catalyst activity and selectivities to branched alkanes was investigated. Acidic chloroaluminate IL catalysts form liquid-liquid biphasic systems with unpolar organic product mixtures. Thus, recycling of the acidic IL is enabled by simple phase separation in the liquid-liquid biphasic reaction mode or the IL can be immobilized on an inorganic support with a large specific surface area. These supported ionic liquid phase (SILP) catalysts offer the advantage to get a macroscopically heterogeneous system while still preserving all benefits of the homogeneous catalyst which can be used for the slurry-phase n-alkane isomerization. The interaction of the solid support and acidic IL influences strongly the catalytic activity. (orig.)

Informed Traders as Liquidity Providers: Anonymity, Liquidity and Price Formation

OpenAIRE

Barbara Rindi

2008-01-01

The tendency to introduce anonymity into financial markets apparently runs counter to the theory supporting transparency. This paper studies the impact of pre-trade transparency on liquidity in a market where risk-averse traders accommodate the liquidity demand of noise traders. When some risk-averse investors become informed, an adverse selection problem ensues for the others, making them reluctant to supply liquidity. Hence the disclosure of traders' identities improves liquidity by mitigat...

Structure of simple liquids; Structure des liquides simples

Energy Technology Data Exchange (ETDEWEB)

Blain, J F [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1969-07-01

The results obtained by application to argon and sodium of the two important methods of studying the structure of liquids: scattering of X-rays and neutrons, are presented on one hand. On the other hand the principal models employed for reconstituting the structure of simple liquids are exposed: mathematical models, lattice models and their derived models, experimental models. (author) [French] On presente d'une part les resultats obtenus par application a l'argon et au sodium des deux principales methodes d'etude de la structure des liquides: la diffusion des rayons X et la diffusion des neutrons; d'autre part, les principaux modeles employes pour reconstituer la structure des liquides simples sont exposes: modeles mathematiques, modeles des reseaux et modeles derives, modeles experimentaux. (auteur)

Optimal Liquidation under Stochastic Liquidity

OpenAIRE

Becherer, Dirk; Bilarev, Todor; Frentrup, Peter

2016-01-01

We solve explicitly a two-dimensional singular control problem of finite fuel type for infinite time horizon. The problem stems from the optimal liquidation of an asset position in a financial market with multiplicative and transient price impact. Liquidity is stochastic in that the volume effect process, which determines the inter-temporal resilience of the market in spirit of Predoiu, Shaikhet and Shreve (2011), is taken to be stochastic, being driven by own random noise. The optimal contro...

An inkjet-printed microfluidic device for liquid-liquid extraction.

Science.gov (United States)

Watanabe, Masashi

2011-04-07

A microfluidic device for liquid-liquid extraction was quickly produced using an office inkjet printer. An advantage of this method is that normal end users, who are not familiar with microfabrication, can produce their original microfluidic devices by themselves. In this method, the printer draws a line on a hydrophobic and oil repellent surface using hydrophilic ink. This line directs a fluid, such as water or xylene, to form a microchannel along the printed line. Using such channels, liquid-liquid extraction was successfully performed under concurrent and countercurrent flow conditions. © The Royal Society of Chemistry 2011

Liquid-liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: from discovery to understanding.

Science.gov (United States)

Billard, Isabelle; Ouadi, Ali; Gaillard, Clotilde

2011-06-01

Liquid-liquid extraction of actinides and lanthanides by use of ionic liquids is reviewed, considering, first, phenomenological aspects, then looking more deeply at the various mechanisms. Future trends in this developing field are presented.

Managing liquidity

DEFF Research Database (Denmark)

Pokutta, Sebastian; Schmaltz, Christian

2011-01-01

Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de......-)centralization. We provide an analytical solution for the 2-branch model and show that a liquidity center can be interpreted as an option on immediate liquidity. Therefore, its value can be interpreted as the price of information, i.e., the price of knowing the exact demand. Furthermore, we derive the threshold...... above which it is advantageous to open a liquidity center and show that it is a function of the volatility and the characteristic of the bank network. Finally, we discuss the n-branch model for real-world banking groups (10-60 branches) and show that it can be solved with high granularity (100 scenarios...

Liquid-liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: from discovery to understanding

International Nuclear Information System (INIS)

Billard, Isabelle; Ouadi, Ali; Gaillard, Clotilde

2011-01-01

Liquid-liquid extraction of actinides and lanthanides by use of ionic liquids is reviewed, considering, first, phenomenological aspects, then looking more deeply at the various mechanisms. Future trends in this developing field are presented. (orig.)

(Liquid + liquid) equilibria of {benzene + cyclohexane + two ionic liquids} at different temperature and atmospheric pressure

International Nuclear Information System (INIS)

Sakal, Salem A.; Shen, Chong; Li, Chun-xi

2012-01-01

Highlights: ► (Liquid + liquid) equilibrium for two quaternary and two ternary systems were measured. ► The components include cyclohexane, benzene, [MIM][BF4], [MIM][ClO4] and [MMIM][DMP]. ► The (liquid + liquid) equilibrium data can be well correlated by the NRTL model. ► Separation of benzene and cyclohexane by pure ILs and their mixtures were discussed. - Abstract: (Liquid + liquid) equilibrium data of the following ternary and quaternary systems at different temperatures and mass fractions of ionic liquids (ILs) were measured at atmospheric pressure, i.e., {cyclohexane + benzene + 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP])} at 298.2 K, {cyclohexane + benzene + 1-methylimidazolium tetrafluoroborate ([MIM][BF 4 ])} at 338.2 K, {cyclohexane + benzene + [MIM][BF 4 ] + [MMIM][DMP]} at (298.2 and 313.2) K, and {cyclohexane + benzene + 1-methylimidazolium perchlorate [MIM][ClO 4 ] + [MMIM][DMP]} at 298.2 K. The results indicate that both selectivity and distribution factor of the IL mixture for benzene are lower than that of pure IL [MMIM][DMP] at a specified condition, and decrease with the increase of the mass fraction of [MIM][BF 4 ] or [MIM][ClO 4 ] in its mixture of [MMIM][DMP] and the mole fraction of benzene. The extremely high selectivity of [MIM][BF 4 ] and [MIM][ClO 4 ] for aromatic compounds as predicted by the COSMOS-RS model is not justified by the present experimental results, and on the contrary, they show a relatively lower selectivity and extraction capacity for benzene than [MMIM][DMP].

Liquid-liquid interfacial tension of electrolyte solutions

NARCIS (Netherlands)

Bier, Markus; Zwanikken, J.W.; van Roij, R.H.H.G.

2008-01-01

It is theoretically shown that the excess liquid-liquid interfacial tension between two electrolyte solutions as a function of the ionic strength I behaves asymptotically as (-) for small I and as (±I) for large I. The former regime is dominated by the electrostatic potential due to an unequal

Liquid phase and supercooled liquid phase welding of bulk metallic glasses

International Nuclear Information System (INIS)

Kawamura, Y.

2004-01-01

Recent progress on welding in bulk metallic glasses (BMGs) has been reviewed. BMGs have been successfully welded to BMGs or crystalline metals by liquid phase welding using explosion, pulse-current and electron-beam methods, and by supercooled liquid phase welding using friction method. Successful welding of the liquid phase methods was due to the high glass-forming ability of the BMGs and the high concentration of welding energy in these methods. In contrast, the supercooled liquid phase welding was successful due to the thermally stable supercooled liquid state of the BMGs and the superplasticity and viscous flow of the supercooled liquid. The successful welding of BMGs to BMGs and crystalline materials is promising for the future development of BMGs as engineering materials

Ionic liquid marbles.

Science.gov (United States)

Gao, Lichao; McCarthy, Thomas J

2007-10-09

Liquid marbles have been reported during this decade and have been argued to be potentially useful for microfluidic and lab-on-a-chip applications. The liquid marbles described to date have been composed of either water or glycerol as the liquid and hydrophobized lycopodium or silica as the stabilizing particles. Both of these components are potentially reactive and do not permit the use of organic chemistry; the liquids are volatile. We report the use of perfluoroalkyl particles (oligomeric (OTFE) and polymeric (PTFE) tetrafluoroethylene, which are unreactive) to support/stabilize a range of ionic liquid marbles. Ionic liquids are not volatile and have been demonstrated to be versatile solvents for chemical transformations. Water marbles prepared with OTFE are much more robust than those prepared with hydrophobized lycopodium or silica.

Phase stability analysis of liquid-liquid equilibrium with stochastic methods

Directory of Open Access Journals (Sweden)

G. Nagatani

2008-09-01

Full Text Available Minimization of Gibbs free energy using activity coefficient models and nonlinear equation solution techniques is commonly applied to phase stability problems. However, when conventional techniques, such as the Newton-Raphson method, are employed, serious convergence problems may arise. Due to the existence of multiple solutions, several problems can be found in modeling liquid-liquid equilibrium of multicomponent systems, which are highly dependent on the initial guess. In this work phase stability analysis of liquid-liquid equilibrium is investigated using the NRTL model. For this purpose, two distinct stochastic numerical algorithms are employed to minimize the tangent plane distance of Gibbs free energy: a subdivision algorithm that can find all roots of nonlinear equations for liquid-liquid stability analysis and the Simulated Annealing method. Results obtained in this work for the two stochastic algorithms are compared with those of the Interval Newton method from the literature. Several different binary and multicomponent systems from the literature were successfully investigated.

The putative liquid-liquid transition is a liquid-solid transition in atomistic models of water. II

Science.gov (United States)

Limmer, David T.; Chandler, David

2013-06-01

This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [D. T. Limmer and D. Chandler, J. Chem. Phys. 135, 134503 (2011), 10.1063/1.3643333 and preprint arXiv:1107.0337 (2011)]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, Stillinger-Weber silicon, and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate using both analytical theory and computer simulation. For the latter, we describe robust methods for computing reversible free energy surfaces, and we consider effects of electrostatic boundary conditions. We show that sensible alterations of models and boundary conditions produce no qualitative changes in low-temperature phase behaviors of these systems, only marginal changes in equations of state. On the other hand, we show that altering sampling time scales can produce large and qualitative non-equilibrium effects. Recent reports of evidence of a liquid-liquid critical point in computer simulations of supercooled water are considered in this light.

The putative liquid-liquid transition is a liquid-solid transition in atomistic models of water. II

International Nuclear Information System (INIS)

Limmer, David T.; Chandler, David

2013-01-01

This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [D. T. Limmer and D. Chandler, J. Chem. Phys.135, 134503 (2011) and preprint http://arxiv.org/abs/arXiv:1107.0337 (2011)]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, Stillinger-Weber silicon, and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate using both analytical theory and computer simulation. For the latter, we describe robust methods for computing reversible free energy surfaces, and we consider effects of electrostatic boundary conditions. We show that sensible alterations of models and boundary conditions produce no qualitative changes in low-temperature phase behaviors of these systems, only marginal changes in equations of state. On the other hand, we show that altering sampling time scales can produce large and qualitative non-equilibrium effects. Recent reports of evidence of a liquid-liquid critical point in computer simulations of supercooled water are considered in this light

The putative liquid-liquid transition is a liquid-solid transition in atomistic models of water. II

Energy Technology Data Exchange (ETDEWEB)

Limmer, David T.; Chandler, David, E-mail: chandler@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States)

2013-06-07

This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [D. T. Limmer and D. Chandler, J. Chem. Phys.135, 134503 (2011) and preprint http://arxiv.org/abs/arXiv:1107.0337 (2011)]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, Stillinger-Weber silicon, and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate using both analytical theory and computer simulation. For the latter, we describe robust methods for computing reversible free energy surfaces, and we consider effects of electrostatic boundary conditions. We show that sensible alterations of models and boundary conditions produce no qualitative changes in low-temperature phase behaviors of these systems, only marginal changes in equations of state. On the other hand, we show that altering sampling time scales can produce large and qualitative non-equilibrium effects. Recent reports of evidence of a liquid-liquid critical point in computer simulations of supercooled water are considered in this light.

The putative liquid-liquid transition is a liquid-solid transition in atomistic models of water. II.

Science.gov (United States)

Limmer, David T; Chandler, David

2013-06-07

This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [D. T. Limmer and D. Chandler, J. Chem. Phys. 135, 134503 (2011) and preprint arXiv:1107.0337 (2011)]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, Stillinger-Weber silicon, and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate using both analytical theory and computer simulation. For the latter, we describe robust methods for computing reversible free energy surfaces, and we consider effects of electrostatic boundary conditions. We show that sensible alterations of models and boundary conditions produce no qualitative changes in low-temperature phase behaviors of these systems, only marginal changes in equations of state. On the other hand, we show that altering sampling time scales can produce large and qualitative non-equilibrium effects. Recent reports of evidence of a liquid-liquid critical point in computer simulations of supercooled water are considered in this light.

Functional implications of short-term retinal detachment in porcine eyes

DEFF Research Database (Denmark)

Kyhn, Maria Voss; Kiilgaard, Jens Folke; Lopez, Ana Garcia

2008-01-01

The aim of the study was to determine the type and magnitude of detectable changes in pig multifocal electroretinography (mfERG) induced by the vitreoretinal surgical procedures necessary to gain access to the subretinal space.......The aim of the study was to determine the type and magnitude of detectable changes in pig multifocal electroretinography (mfERG) induced by the vitreoretinal surgical procedures necessary to gain access to the subretinal space....

Theoretical background and the flow fields in downhole liquid-liquid hydrocyclone (LLHC

Directory of Open Access Journals (Sweden)

Osei Harrison

2014-07-01

Full Text Available Hydrocyclone system for downhole oil-water separation provides an effective technique of enhancing the economic viability of higher water-cut wells while at the same time reducing the risk of environmental pollution. This paper describes the hydrodynamics of the liquid-liquid hydrocyclones and the flow fields within it are paramount for achieving successful separation process. Some of the important hydrodynamic flow phenomenon within the liquid-liquid hydrocyclone and how they influence the separation efficiency of water/oil was analyzed through analytical solution. The properties of the liquids were based on Bayan offshore field measured properties. The results indicated that there are two swirling zones separated by stagnant flow field. The inner is the light liquid zone, while the outer is the heavy liquid zone.

Heat transfer on liquid-liquid interface of molten-metal and water

International Nuclear Information System (INIS)

Tanaka, T.; Saito, Yasushi; Mishima, Kaichiro

2001-01-01

Molten-core pool had been formed in the lower-head of TMI-2 pressure vessel at the severe accident. The lower head, however, didn't receive any damage by reactor core cooling. Heat transfer at outside of the lower head and boiling heat transfer at liquid-liquid interface of molten-metal and water, however, are important for initial cooling process of the molten-core pool. The heat transfer experiments for the liquid-liquid interface of molten-metal and water are carried out over the range of natural convection to film boiling region. Phenomenon on the heat transfer experiments are visualized by using of high speed video camera. Wood's metal and U-alloy 78 are used as molten-metal. The test section of the experiments consists of a copper block with heater, wood's metal, and water. Three thermocouple probes are used for temperature measurement of water side and the molten-metal side. Stability of the liquid-liquid interface is depended on the wetness of container wall for molten metal and the temperature distribution of the interface. Entrainment phenomena of molten-metal occurs by a fluctuation of the interface after boiling on the container wall surface. The boiling curves obtained from the liquid-liquid interface experiments are agree with the nucleate boiling and the film boiling correlations of solid-liquid system. (Suetake, M.)

Determination of chlorophenols in honey samples using in-situ ionic liquid-dispersive liquid-liquid microextraction as a pretreatment method followed by high-performance liquid chromatography.

Science.gov (United States)

Fan, Chen; Li, Nai; Cao, Xueli

2015-05-01

In-situ ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a pretreatment method for the detection of six chlorophenols (CPs) in honey samples. The hydrophobic ionic liquid [C4MIM][NTf2], formed in-situ by the hydrophilic ionic liquid [C4MIM][BF4] and the ion exchange reagent LiNTf2 was used as the microextractant solvent of CPs from honey sample. Then the enriched analytes were back-extracted into 40 μL of 0.14 M NaOH solution and finally subjected to analysis by high-performance liquid chromatography. The method showed low limit of detection of CPs, 0.8-3.2 μg/L and high enrichment factor, 34-65 with the recoveries range from 91.60% to 114.33%. The method is simple, rapid, environmentally friendly and with high extraction efficiency. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Putative Liquid-Liquid Transition is a Liquid-Solid Transition in Atomistic Models of Water

Science.gov (United States)

Chandler, David; Limmer, David

2013-03-01

Our detailed and controlled studies of free energy surfaces for models of water find no evidence for reversible polyamorphism, and a general theoretical analysis of the phase behavior of cold water in nano pores shows that measured behaviors of these systems reflect surface modulation and dynamics of ice, not a liquid-liquid critical point. A few workers reach different conclusions, reporting evidence of a liquid-liquid critical point in computer simulations of supercooled water. In some cases, it appears that these contrary results are based upon simulation algorithms that are inconsistent with principles of statistical mechanics, such as using barostats that do not reproduce the correct distribution of volume fluctuations. In other cases, the results appear to be associated with difficulty equilibrating the supercooled material and mistaking metastability for coarsening of the ordered ice phase. In this case, sufficient information is available for us to reproduce the contrary results and to establish that they are artifacts of finite time sampling. This finding leads us to the conclusion that two distinct, reversible liquid phases do not exist in models of supercooled water.

The Liquid State

Indian Academy of Sciences (India)

like iron, aluminium, lead, zinc, etc .. Metals are cast ... dropping molten liquid of the alloys on a rapidly spinning copper wheel. ... Ed. Computer simulation studies in ... liquids, modelling ofliquids and study of the dynamic behaviour of liquids ...

Liquid sodium pumps

International Nuclear Information System (INIS)

Allen, H.G.

1985-01-01

The pump for use in a nuclear reactor cooling system comprises a booster stage impeller for drawing the liquid through the inlet. A diffuser is affixedly disposed within the pump housing to convert the kinetic pressure imparted to the liquid into increased static pressure. A main stage impeller is rotatively driven by a pump motor at a relatively high speed to impart a relatively high static pressure to the liquid and for discharging the liquid at a relatively high static pressure. A hydraulic coupling is disposed remotely from the liquid path for hydraulically coupling the main stage impeller and the booster stage impeller to rotate the booster stage impeller at a relatively low speed to maintain the low net positive suction pressure applied to the liquid at the inlet greater than the vapor pressure of the liquid and to ensure that the low net positive suction heat, as established by the main stage impeller exceeds the vapor pressure. The coupling comprises a grooved drum which rotates between inner and outer drag coupling members. In a modification the coupling comprises a torque converter. (author)

Liquid-liquid extraction in flow analysis: A critical review

Energy Technology Data Exchange (ETDEWEB)

Silvestre, Cristina I.C.; Santos, Joao L.M. [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Lima, Jose L.F.C., E-mail: limajlfc@ff.up.pt [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Zagatto, Elias A.G. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, P.O. Box 96, Piracicaba 13400-970 (Brazil)

2009-10-12

Liquid-liquid extractions (LLE) are a common sample pre-treatment in many analytical applications. This review aims at providing a critical overview of the distinct automated continuous flow-based approaches that were developed for liquid-liquid extraction with the purpose of pre-concentration and/or separation of multiple analytes, such as ultra-trace metal and metalloid species, phenolic compounds, surfactants, pharmaceuticals, etc., hyphenated with many detection technique such as UV/vis spectrophotometry, atomic spectrometric detection systems and luminescent detectors, including distinct extraction strategies and applications like single and multiple extraction schemes, wetting film extraction, supported liquid membrane extraction, back extraction, closed-loop systems and the utilisation of zone sampling, chromatomembranes and iterative reversal techniques. The analytical performance of the developed flow-based LLE methods and the influence of flow manifold components such as the segmenter, extraction coil and phase separator, is emphasised and object of discussion. An overall presentation of each system components, selectivity, advantages and shortcomings is carried out and exemplified with selected applications.

Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

Science.gov (United States)

Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

2015-12-08

An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

Parallel artificial liquid membrane extraction

DEFF Research Database (Denmark)

Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine

2013-01-01

This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti......This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

Laser ablation of liquid surface in air induced by laser irradiation through liquid medium

Science.gov (United States)

Utsunomiya, Yuji; Kajiwara, Takashi; Nishiyama, Takashi; Nagayama, Kunihito; Kubota, Shiro; Nakahara, Motonao

2010-10-01

The pulse laser ablation of a liquid surface in air when induced by laser irradiation through a liquid medium has been experimentally investigated. A supersonic liquid jet is observed at the liquid-air interface. The liquid surface layer is driven by a plasma plume that is produced by laser ablation at the layer, resulting in a liquid jet. This phenomenon occurs only when an Nd:YAG laser pulse (wavelength: 1064 nm) is focused from the liquid onto air at a low fluence of 20 J/cm2. In this case, as Fresnel’s law shows, the incident and reflected electric fields near the liquid surface layer are superposed constructively. In contrast, when the incident laser is focused from air onto the liquid, a liquid jet is produced only at an extremely high fluence, several times larger than that in the former case. The similarities and differences in the liquid jets and atomization processes are studied for several liquid samples, including water, ethanol, and vacuum oil. The laser ablation of the liquid surface is found to depend on the incident laser energy and laser fluence. A pulse laser light source and high-resolution film are required to observe the detailed structure of a liquid jet.

Liquid-liquid phase transition and glass transition in a monoatomic model system.

Science.gov (United States)

Xu, Limei; Buldyrev, Sergey V; Giovambattista, Nicolas; Stanley, H Eugene

2010-01-01

We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

Liquid-Liquid Phase Transition and Glass Transition in a Monoatomic Model System

Directory of Open Access Journals (Sweden)

Nicolas Giovambattista

2010-12-01

Full Text Available We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

WIDEFIELD SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY IMAGING OF PERIPHERAL ROUND RETINAL HOLES WITH OR WITHOUT RETINAL DETACHMENT.

Science.gov (United States)

Casswell, Edward J; Abou Ltaif, Sleiman; Carr, Thomas; Keane, Pearse A; Charteris, David G; Wickham, Louisa

2018-03-02

To describe the widefield spectral-domain optical coherence tomography features of peripheral round retinal holes, with or without associated retinal detachment (RD). Retrospective, observational study of 28 eyes with peripheral round retinal holes, with and without RD. Patients underwent imaging with a widefield 50-degree spectral-domain optical coherence tomography (Heidelberg Engineering, Germany) and Optos ultra-widefield imaging systems (Optos, United Kingdom). Vitreous attachment at the site of the retinal hole was detected in 27/28 (96.4%) cases. Cases were split into three groups: RHs with RD (n = 12); RHs with subretinal fluid (n = 5), and flat RHs (n = 11), with minimal or no subretinal fluid. 91.6% retinal holes associated with subretinal fluid or RD had vitreous attachment at the site of the hole. Eighty percent had vitreous attachment at both edges of the retinal hole, in a U-shape configuration, which appeared to exert traction. By contrast, flat retinal holes had visible vitreous attachment only at one edge of the retinal hole in 45.4%. Vitreous attachment was commonly seen at the site of round retinal holes. Vitreous attachment at both edges of the retinal hole in a U-shape configuration was more commonly seen at holes associated with subretinal fluid or RD.

Preservation of photoreceptors in dystrophic RCS rats following allo- and xenotransplantation of IPE cells.

Science.gov (United States)

Thumann, Gabriele; Salz, Anna Katharina; Walter, Peter; Johnen, Sandra

2009-03-01

To examine whether iris pigment epithelial (IPE) cells transplanted into the subretinal space of Royal College of Surgeons (RCS) rats have the ability to rescue photoreceptors. Rat IPE (rIPE) or human IPE (hIPE) cells were transplanted subretinally in 23-day-old RCS rats. Sham injection and transplantation of ARPE-19 cells served as controls. After 12 weeks, eyes were evaluated for photoreceptor survival by morphometric analysis and electron microscopy. Morphometric analysis showed photoreceptor rescue in all transplanted and sham-injected animals (number of photoreceptors/300 microm retina+/-sd: rIPE 41.67 +/- 28; hIPE 29.50 +/- 16; ARPE-19 36.12 +/- 21; sham 16.56 +/- 6) compared to age-matched, control rats (number of photoreceptors/300 microm retina+/-sd: 9.71 +/- 4). Photoreceptor rescue was prominent in IPE cell-transplanted rats and was significantly greater than sham-injected eyes (p = 0.02 for rIPE and p = 0.04 for hIPE). Since IPE cells transplanted into the subretinal space have the ability to rescue photoreceptors from degeneration in the RCS rat without any harmful effects, IPE cells may represent an ideal cell to genetically modify and thus carry essential genetic information for the repair of defects in the subretinal space.

Flow transition criteria of a liquid jet into a liquid pool

Energy Technology Data Exchange (ETDEWEB)

Saito, Shimpei, E-mail: s1630195@u.tsukuba.ac.jp [Graduate School of Systems and Information Engineering, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Abe, Yutaka [Faculty of Engineering, Information and Systems, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Koyama, Kazuya [Reactor Core and Safety Design Department, Mitsubishi FBR Systems, Inc., 2-34-17 Jingumae, Shibuya, Tokyo 150-0001 (Japan)

2017-04-15

Highlights: • Jet breakup and droplet formation in immiscible liquid-liquid systems was studied experimentally. • The observed jet breakup behavior was classified into characteristic regimes. • The droplet size distribution was analyzed using image processing. • The variation of droplet size was compared with available melt-jet experiments. • Extrapolation to the expected SFR conditions implied that most of the hydrodynamic conditions would be the atomization regime. - Abstract: To better understand the fundamental interactions between melt jet and coolant during a core-disruptive accident at a sodium-cooled fast reactor, the jet breakup and droplet formation in immiscible liquid-liquid systems were studied experimentally. Experiments using two different pairs of test fluids were carried out at isothermal conditions. The observed jet breakup behavior was classified into characteristic regimes based on the classical Ohnesorge classification in liquid-gas systems. The variation in breakup length obtained in the present liquid-liquid system was similar to that in a liquid-gas system. The droplet size distribution in each breakup regime was analyzed using image processing and droplet formation via pinch-off, satellite formation, and entrainment was observed. The measured droplet size was compared with those available from melt jet experiments. Based on the observation and analysis results, the breakup regimes were organized on a dimensionless operating diagram, with the derived correlations representing the criteria for regime boundaries of a liquid-liquid system. Finally, the experimental data were extrapolated to the expected conditions of a sodium-cooled fast reactor. From this, it was implied that most of the hydrodynamic conditions during an accident would be close to the atomization regime, in which entrainment is the dominant process for droplet formation.

Liquid Sloshing Dynamics

Science.gov (United States)

Ibrahim, Raouf A.

2005-06-01

The problem of liquid sloshing in moving or stationary containers remains of great concern to aerospace, civil, and nuclear engineers; physicists; designers of road tankers and ship tankers; and mathematicians. Beginning with the fundamentals of liquid sloshing theory, this book takes the reader systematically from basic theory to advanced analytical and experimental results in a self-contained and coherent format. The book is divided into four sections. Part I deals with the theory of linear liquid sloshing dynamics; Part II addresses the nonlinear theory of liquid sloshing dynamics, Faraday waves, and sloshing impacts; Part III presents the problem of linear and nonlinear interaction of liquid sloshing dynamics with elastic containers and supported structures; and Part IV considers the fluid dynamics in spinning containers and microgravity sloshing. This book will be invaluable to researchers and graduate students in mechanical and aeronautical engineering, designers of liquid containers, and applied mathematicians.

Liquid dispersion in trickle-bed reactors with gas-liquid cocurrent downflow

International Nuclear Information System (INIS)

Chu, C.F.; Ng, K.M.

1986-01-01

The flow pattern can deviate from ideal plug flow in both trickling and pulsing flows. The liquid dispersion in those flow regimes are investigated separately, as the mechanisms causing the deviation of flow pattern from plug flow are different. In trickling flow, the dispersion of the liquid phase occurs in the flow path which is determined with computer-generated packed column. Dispersion in pulsing flow is studied with a combination of the method of characteristics and analysis of liquid dispersion in the liquid slug and gas pulse. The axial dispersion coefficients are then determined based on Monte Carlo simulation. Finally, liquid dispersion in trickle beds containing porous packings is also discussed

Fractional Consumption of Liquid Hydrogen and Liquid Oxygen During the Space Shuttle Program

Science.gov (United States)

Partridge, Jonathan K.

2011-01-01

The Space Shuttle uses the propellants, liquid hydrogen and liquid oxygen, to meet part of the propulsion requirements from ground to orbit. The Kennedy Space Center procured over 25 million kilograms of liquid hydrogen and over 250 million kilograms of liquid oxygen during the 3D-year Space Shuttle Program. Because of the cryogenic nature of the propellants, approximately 55% of the total purchased liquid hydrogen and 30% of the total purchased liquid oxygen were used in the Space Shuttle Main Engines. The balance of the propellants were vaporized during operations for various purposes. This paper dissects the total consumption of liqUid hydrogen and liqUid oxygen and determines the fraction attributable to each of the various processing and launch operations that occurred during the entire Space Shuttle Program at the Kennedy Space Center.

Hybrid Multiphase CFD Solver for Coupled Dispersed/Segregated Flows in Liquid-Liquid Extraction

Directory of Open Access Journals (Sweden)

Kent E. Wardle

2013-01-01

Full Text Available The flows in stage-wise liquid-liquid extraction devices include both phase segregated and dispersed flow regimes. As a additional layer of complexity, for extraction equipment such as the annular centrifugal contactor, free-surface flows also play a critical role in both the mixing and separation regions of the device and cannot be neglected. Traditionally, computional fluid dynamics (CFD of multiphase systems is regime dependent—different methods are used for segregated and dispersed flows. A hybrid multiphase method based on the combination of an Eulerian multifluid solution framework (per-phase momentum equations and sharp interface capturing using Volume of Fluid (VOF on selected phase pairs has been developed using the open-source CFD toolkit OpenFOAM. Demonstration of the solver capability is presented through various examples relevant to liquid-liquid extraction device flows including three-phase, liquid-liquid-air simulations in which a sharp interface is maintained between each liquid and air, but dispersed phase modeling is used for the liquid-liquid interactions.

Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air.

Science.gov (United States)

Men, Yongjun; Ambrogi, Martina; Han, Baohang; Yuan, Jiayin

2016-04-08

Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m²/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection.

Electrophoretic transport of biomolecules across liquid-liquid interfaces

Energy Technology Data Exchange (ETDEWEB)

Hahn, Thomas; Hardt, Steffen [Center of Smart Interfaces, TU Darmstadt, Petersenstrasse 32, D-64287 Darmstadt (Germany); Muenchow, Goetz, E-mail: hardt@csi.tu-darmstadt.de [Institut fuer Mikrotechnik Mainz GmbH, Carl-Zeiss-Strasse 18-20, D-55129 Mainz (Germany)

2011-05-11

The mass transfer resistance of a liquid-liquid interface in an aqueous two-phase system composed of poly(ethylene glycol) and dextran is investigated. Different types of proteins and DNA stained with fluorescent dyes serve as probes to study the transport processes close to the interface. A microfluidic device is employed to enable the electrophoretic transport of biomolecules from one phase to another. The results obtained for proteins can be explained solely via the different electrophoretic mobilities and different affinities of the molecules to the two phases, without any indications of a significant mass transfer resistance of the liquid-liquid interface. By contrast, DNA molecules adsorb to the interface and only desorb under an increased electric field strength. The desorption process carries the signature of a thermally activated escape from a metastable state, as reflected in the exponential decay of the fluorescence intensity at the interface as a function of time.

Liquid-liquid extraction by reversed micelles in biotechnological processes

Directory of Open Access Journals (Sweden)

Kilikian B. V.

2000-01-01

Full Text Available In biotechnology there is a need for new purification and concentration processes for biologically active compounds such as proteins, enzymes, nucleic acids, or cells that combine a high selectivity and biocompatibility with an easy scale-up. A liquid-liquid extraction with a reversed micellar phase might serve these purposes owing to its capacity to solubilize specific biomolecules from dilute aqueous solutions such as fermentation and cell culture media. Reversed micelles are aggregates of surfactant molecules containing an inner core of water molecules, dispersed in a continuous organic solvent medium. These reversed micelles are capable of selectively solubilizing polar compounds in an apolar solvent. This review gives an overview of liquid-liquid extraction by reversed micelles for a better understanding of this process.

Liquid hydrogen in Japan

Energy Technology Data Exchange (ETDEWEB)

Yasumi, S. [Iwatani Corp., Osaka (Japan). Dept. of Overseas Business Development

2009-07-01

Japan's Iwatani Corporation has focused its attention on hydrogen as the ultimate energy source in future. Unlike the United States, hydrogen use and delivery in liquid form is extremely limited in the European Union and in Japan. Iwatani Corporation broke through industry stereotypes by creating and building Hydro Edge Co. Ltd., Japan's largest liquid hydrogen plant. It was established in 2006 as a joint venture between Iwatani and Kansai Electric Power Group in Osaka. Hydro Edge is Japan's first combined liquid hydrogen and ASU plant, and is fully operational. Liquid oxygen, liquid nitrogen and liquid argon are separated from air using the cryogenic energy of liquefied natural gas fuel that is used for power generation. Liquid hydrogen is produced efficiently and simultaneously using liquid nitrogen. Approximately 12 times as much hydrogen in liquid form can be transported and supplied as pressurized hydrogen gas. This technology is a significant step forward in the dissemination and expansion of hydrogen in a hydrogen-based economy.

Measuring liquidity on stock market: impact on liquidity ratio

OpenAIRE

Siniša Bogdan; Suzana Bareša; Saša Ivanović

2012-01-01

The purpose – It is important to emphasize that liquidity on Croatian stock market is low, the purpose of this paper is to test empirically and find out which variables make crucial role in decision making process of investing in stocks. Design – This paper explores the impact of various liquidity variables on liquidity ratio since it is still insufficiently researched topic. Methodology –This research uses secondary and primary data available from Croatian stock market. Considering pri...

Kinetics of glycoalkaloid hydrolysis and solanidine extraction in liquid-liquid systems

Directory of Open Access Journals (Sweden)

Stanković Mihajlo Z.

2002-01-01

Full Text Available The kinetics of glycoalkaloid hydrolysis and solanidine extraction in Analyzed in this study. obtained from dried and milled potato haulm to to which hydrochlotic acid was added is the first liquid phase, while chloroform trichloroethylene or carbon tetrachlondeisthe second organic, liquid phase. The purpose of this paper was to combine the processes of glycoalkaloid hydrolysis to solanidine and solanidine extraction into one step, and to find the optimal liquid-liquid system for such a process.

Further evidence of a liquid-liquid transition in interfacial water

International Nuclear Information System (INIS)

Zanotti, J-M; Bellissent-Funel, M C; Chen, S-H; Kolesnikov, A I

2006-01-01

In a previous paper we combined calorimetric, diffraction and high-resolution quasi-elastic neutron scattering data to show that after exhibiting a glass transition at 165 K, interfacial water experiences a first order liquid-liquid transition at 240 K from a low-density to a high-density liquid. Here we present further evidence of these transitions obtained by high-energy inelastic neutron scattering

Thermal properties of ionic systems near the liquid-liquid critical point.

Science.gov (United States)

Méndez-Castro, Pablo; Troncoso, Jacobo; Pérez-Sánchez, Germán; Peleteiro, José; Romaní, Luis

2011-12-07

Isobaric heat capacity per unit volume, C(p), and excess molar enthalpy, h(E), were determined in the vicinity of the critical point for a set of binary systems formed by an ionic liquid and a molecular solvent. Moreover, and, since critical composition had to be accurately determined, liquid-liquid equilibrium curves were also obtained using a calorimetric method. The systems were selected with a view on representing, near room temperature, examples from clearly solvophobic to clearly coulombic behavior, which traditionally was related with the electric permittivity of the solvent. The chosen molecular compounds are: ethanol, 1-butanol, 1-hexanol, 1,3-dichloropropane, and diethylcarbonate, whereas ionic liquids are formed by imidazolium-based cations and tetrafluoroborate or bis-(trifluromethylsulfonyl)amide anions. The results reveal that solvophobic critical behavior-systems with molecular solvents of high dielectric permittivity-is very similar to that found for molecular binary systems. However, coulombic systems-those with low permittivity molecular solvents-show strong deviations from the results usually found for these magnitudes near the liquid-liquid phase transition. They present an extremely small critical anomaly in C(p)-several orders of magnitude lower than those typically obtained for binary mixtures-and extremely low h(E)-for one system even negative, fact not observed, up to date, for any liquid-liquid transition in the nearness of an upper critical solution temperature. © 2011 American Institute of Physics

Resistance probe for liquid hydrogen; Sonde a resistance pour l'hydrogene liquide

Energy Technology Data Exchange (ETDEWEB)

Beauval, J J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

A simple device for determining the level of a liquid in equilibrium with its vapour is described. It makes use of the variation in heat exchange between a filament heated by a current and the atmosphere, on passing from the liquid to the gas. This apparatus is used to measure liquid hydrogen levels in liquefying dewar vessels. (author) [French] On decrit un dispositif simple permettant de determiner le niveau d'un liquide en equilibre avec sa vapeur. Il utilise la variation de l'echange thermique entre un filament chauffe par un courant et le milieu ambiant, quand on passe du liquide au gaz. Cet appareil est utilise pour mesurer des niveaux d'hydrogene liquide dans les dewars du liquefacteur. (auteur)

Ionic liquid-based air-assisted liquid-liquid microextraction followed by high performance liquid chromatography for the determination of five fungicides in juice samples.

Science.gov (United States)

You, Xiangwei; Chen, Xiaochu; Liu, Fengmao; Hou, Fan; Li, Yiqiang

2018-01-15

A novel and simple ionic liquid-based air-assisted liquid-liquid microextraction technique combined with high performance liquid chromatography was developed to analyze five fungicides in juice samples. In this method, ionic liquid was used instead of a volatile organic solvent as the extraction solvent. The emulsion was formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent repeatedly using a 10mL glass syringe. No organic dispersive solvent was required. Under the optimized conditions, the limits of detection (LODs) were 0.4-1.8μgL -1 at a signal-to-noise ratio of 3. The limits of quantification (LOQs) set as the lowest spiking levels with acceptable recovery in juices were 10μgL -1 , except for fludioxonil whose LOQ was 20μgL -1 . The proposed method was applied to determine the target fungicides in juice samples, and acceptable recoveries ranging from 74.9% to 115.4% were achieved. Copyright © 2017. Published by Elsevier Ltd.

Systemic Liquidity Shocks and Banking Sector Liquidity Characteristics on the Eve of Liquidity Coverage Ratio Application - The Case of the Czech Republic1

Directory of Open Access Journals (Sweden)

Brůna Karel

2016-01-01

Full Text Available The paper contains an analysis of the economic and regulatory concept of bank liquidity in the context of systemic liquidity shock. A formal model analysis shows that the application of liquidity coverage ratio (LCR based on Basel III will lead to a significant adaptation of banks liquidity management. LCR causes a change in bank’s liquidity allocation and funding to be less effective and more costly and restrictive for providing credits comparing with economic determinants. It is demonstrated that the application of LCR underestimates actual liquidity position of a bank and leads to allocation ineffectiveness. The empirical part contains simulation of impacts of systemic liquidity shock on the banking sector’s ability to withstand the unfavourable credit shock while solvency is maintained. The results confirm the robustness of the Czech banking system ensuing from the systemic surplus of liquidity, high volume of bank capital and its high profitability. The estimations of the VAR model show that the relations between liquidity characteristics of banks, sources of aggregate liquidity shock, interbank market illiquidity and the credit facilities of the Czech National Bank are relatively weak, supporting the conclusion that the banks face liquidity shocks of non-persistent character.

Coalescence dynamics of mobile and immobile fluid interfaces

KAUST Repository

Vakarelski, Ivan Uriev

2018-01-12

Coalescence dynamics between deformable bubbles and droplets can be dramatically affected by the mobility of the interfaces with fully tangentially mobile bubble-liquid or droplet-liquid interfaces expected to accelerate the coalescence by orders of magnitudes. However, there is a lack of systematic experimental investigations that quantify this effect. By using high speed camera imaging we examine the free rise and coalescence of small air-bubbles (100 to 1300 μm in diameter) with a liquid interface. A perfluorocarbon liquid, PP11 is used as a model liquid to investigate coalescence dynamics between fully-mobile and immobile deformable interfaces. The mobility of the bubble surface was determined by measuring the terminal rise velocity of small bubbles rising at Reynolds numbers, Re less than 0.1 and the mobility of free PP11 surface by measuring the deceleration kinetics of the small bubble toward the interface. Induction or film drainage times of a bubble at the mobile PP11-air surface were found to be more than two orders of magnitude shorter compared to the case of bubble and an immobile PP11-water interface. A theoretical model is used to illustrate the effect of hydrodynamics and interfacial mobility on the induction time or film drainage time. The results of this study are expected to stimulate the development of a comprehensive theoretical model for coalescence dynamics between two fully or partially mobile fluid interfaces.

Evaluating the Liquid Liquid Phase Transition Hypothesis of Supercoooled Water

Science.gov (United States)

Limmer, David; Chandler, David

2011-03-01

To explain the anomalous behavior of supercooled water it has been conjectured that buried within an experimentally inaccessible region of liquid water's phase diagram there exists a second critical point, which is the terminus of a first order transition line between two distinct liquid phases. The so-called liquid-liquid phase transition (LLPT) has since generated much study, though to date there is no consensus on its existence. In this talk, we will discuss our efforts to systematically study the metastable phase diagram of supercooled water through computer simulation. By employing importance-sampling techniques, we have calculated free energies as a function of the density and long-range order to determine unambiguously if two distinct liquid phases exist. We will argue that, contrary to the LLPT hypothesis, the observed phenomenology can be understood as a consequence of the limit of stability of the liquid far away from coexistence. Our results suggest that homogeneous nucleation is the cause of the increased fluctuations present upon supercooling. Further we will show how this understanding can be extended to explain experimental observations of hysteresis in confined supercooled water systems.

On the prediction of spray angle of liquid-liquid pintle injectors

Science.gov (United States)

Cheng, Peng; Li, Qinglian; Xu, Shun; Kang, Zhongtao

2017-09-01

The pintle injector is famous for its capability of deep throttling and low cost. However, the pintle injector has been seldom investigated. To get a good prediction of the spray angle of liquid-liquid pintle injectors, theoretical analysis, numerical simulations and experiments were conducted. Under the hypothesis of incompressible and inviscid flow, a spray angle formula was deduced from the continuity and momentum equations based on a control volume analysis. The formula was then validated by numerical and experimental data. The results indicates that both geometric and injection parameters affect the total momentum ratio (TMR) and then influence the spray angle formed by liquid-liquid pintle injectors. TMR is the pivotal non-dimensional number that dominates the spray angle. Compared with gas-gas pintle injectors, spray angle formed by liquid-liquid injectors is larger, which benefits from the local high pressure zone near the pintle wall caused by the impingement of radial and axial sheets.

Essays on bank liquidity : contributions to the measurement of liquidity risk and to the management of bank liquidity production

OpenAIRE

Soula , Jean-Loup

2017-01-01

Bank liquidity risk reflects the function of banks to create liquidity. Banks are fragile, exposed to the possibility of runs from short-term creditors. This dissertation contributes to a better understanding of bank liquidity risk. The second chapter proposes a measure of bank fragility based on the value of the assets held by a bank. Results confirm, in an original way, the fragile nature of banks. However, bank liquidity creation benefits to the economy. The third chapter analyses the capa...

Giant slip at liquid-liquid interfaces using hydrophobic ball bearings.

Science.gov (United States)

Ehlinger, Quentin; Joly, Laurent; Pierre-Louis, Olivier

2013-03-08

Liquid-gas-liquid interfaces stabilized by hydrophobic beads behave as ball bearings under shear and exhibit a giant slip. Using a scaling analysis and molecular dynamics simulations we predict that, when the contact angle θ between the beads and the liquid is large, the slip length diverges as Rρ(-1)(π-θ)(-3) where R is the bead radius, and ρ is the bead density.

Novel routes to metal nanoparticles : electrodeposition and reactions at liquid-liquid interfaces

OpenAIRE

Johans, Christoffer

2003-01-01

This thesis considers the nucleation and growth, synthesis, and catalytic application of metallic nanoparticles at liquid|liquid interfaces. It comprises five publications, a previously unpublished synthesis of polymer coated palladium nanoparticles, and an introduction to the relevant literature. Three publications are concerned with electrodeposition of metal nanoparticles at liquid|liquid interfaces. One publication and the results presented here consider the synthesis of silver and pallad...

Ionic liquids as electrolytes

International Nuclear Information System (INIS)

Galinski, Maciej; Lewandowski, Andrzej; Stepniak, Izabela

2006-01-01

Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batteries and in electrochemical capacitors

Decompression-induced melting of ice IV and the liquid-liquid transition in water

Science.gov (United States)

Mishima, Osamu; Stanley, H. Eugene

1998-03-01

Although liquid water has been the focus of intensive research for over 100 years, a coherent physical picture that unifies all of the known anomalies of this liquid, is still lacking. Some of these anomalies occur in the supercooled region, and have been rationalized on the grounds of a possible retracing of the liquid-gas spinodal (metastability limit) line into the supercooled liquid region, or alternatively the presence of a line of first-order liquid-liquid phase transitions in this region which ends in a critical point,. But these ideas remain untested experimentally, in part because supercooled water can be probed only above the homogeneous nucleation temperature TH at which water spontaneously crystallizes. Here we report an experimental approach that is not restricted by the barrier imposed by TH, involving measurement of the decompression-induced melting curves of several high-pressure phases of ice in small emulsified droplets. We find that the melting curve for ice IV seems to undergo a discontinuity at precisely the location proposed for the line of liquid-liquid phase transitions. This is consistent with, but does not prove, the coexistence of two different phases of (supercooled) liquid water. From the experimental data we calculate a possible Gibbs potential surface and a corresponding equation of state for water, from the forms of which we estimate the coordinates of the liquid-liquid critical point to be at pressure Pc ~ 0.1GPa and temperature Tc ~ 220K.

Corrosion by liquid metals - Application to liquid sodium

International Nuclear Information System (INIS)

Lavielle, Lisette.

1978-10-01

In this bibliographic review on the corrosion by liquid metals, the first part is devoted to the theoretical aspects of the problem and the second part concerns the corrosion of steels by liquid sodium, as example. Obvious the numerous works now published, the mechanisms are still leaving bad known [fr

Macular Morphology and Visual Acuity in the Second Year of the Comparison of Age-Related Macular Degeneration Treatments Trials.

Science.gov (United States)

Sharma, Sumit; Toth, Cynthia A; Daniel, Ebenezer; Grunwald, Juan E; Maguire, Maureen G; Ying, Gui-Shuang; Huang, Jiayan; Martin, Daniel F; Jaffe, Glenn J

2016-04-01

To describe the association between morphologic features on fundus photography (FP), fluorescein angiography (FA), and optical coherence tomography (OCT) and visual acuity (VA) in the second year of the Comparison of Age-related Macular Degeneration Treatments Trials (CATT). Prospective cohort study within a randomized clinical trial. Participants in the CATT. Study eye eligibility required angiographic and OCT evidence of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) and VA between 20/25 and 20/320. Treatment was assigned randomly to ranibizumab or bevacizumab with 3 different dosing regimens over a 2-year period. Fluid type, location, and thickness; retina and subretinal tissue complex thickness on OCT; size and lesion composition on FP and FA; and VA. Among 1185 CATT participants, 993 (84%) had fluid on OCT at baseline and completed 2 years of follow-up. At 2 years, intraretinal fluid (IRF), subretinal fluid (SRF), sub-retinal pigment epithelium (RPE) fluid, and subretinal tissue complex thickness decreased in all treatment groups. Ranibizumab monthly was best able to resolve each type of fluid. Eyes with SRF in the foveal center on OCT had better mean VA than eyes with no SRF (72.8 vs. 66.6 letters; P = 0.006). Eyes with IRF in the foveal center had worse mean VA than eyes without IRF (59.9 vs. 70.9 letters; P 212 μm (59.4 vs. 71.3 vs. 70.3 letters; P < 0.0001). At 2 years, the mean VA (letters) of eyes varied substantially by the type of subfoveal pathology on FP and FA: 70.6 for no pathology; 74.1 for fluid only; 73.3 for CNV or pigment epithelial (RPE) detachment; 68.4 for nongeographic atrophy; and 62.9 for geographic atrophy, hemorrhage, RPE tear, or scar (P < 0.0001). The associations between VA and morphologic features identified through year 1 were maintained or strengthened during year 2. Eyes with foveal IRF, abnormally thin retina, greater thickness of the subretinal tissue complex on OCT, and subfoveal

Liquid Marbles

KAUST Repository

Khalil, Kareem

2012-12-01

Granulation, the process of formation of granules from a combination of base powders and binder liquids, has been a subject of research for almost 50 years, studied extensively for its vast applications, primarily to the pharmaceutical industry sector. The principal aim of granulation is to form granules comprised of the active pharmaceutical ingredients (API’s), which have more desirable handling and flowability properties than raw powders. It is also essential to ensure an even distribution of active ingredients within a tablet with the goal of achieving time‐controlled release of drugs. Due to the product‐specific nature of the industry, however, data is largely empirical [1]. For example, the raw powders used can vary in size by two orders of magnitude with narrow or broad size distributions. The physical properties of the binder liquids can also vary significantly depending on the powder properties and required granule size. Some significant progress has been made to better our understanding of the overall granulation process [1] and it is widely accepted that the initial nucleation / wetting stage, when the binder liquid first wets the powders, is key to the whole process. As such, many experimental studies have been conducted in attempt to elucidate the physics of this first stage [1], with two main mechanisms being observed – classified by Ivenson [1] as the “Traditional description” and the “Modern Approach”. See Figure 1 for a graphical definition of these two mechanisms. Recent studies have focused on the latter approach [1] and a new, exciting development in this field is the Liquid Marble. This interesting formation occurs when a liquid droplet interacts with a hydrophobic (or superhydrophobic) powder. The droplet can become encased in the powder, which essentially provides a protective “shell” or “jacket” for the liquid inside [2]. The liquid inside is then isolated from contact with other solids or liquids and has some

SISAK liquid-liquid extraction experiments with preseparated {sup 257}Rf

Energy Technology Data Exchange (ETDEWEB)

Omtvedt, Jon Petter; Alstad, J.; Breivik, H. [University of Oslo, Department of Chemistry, Oslo (NO)] (and others)

2002-06-01

The SISAK liquid-liquid extraction system was used to extract 4.0-s {sup 257}Rf. The {sup 257}Rf was produced in the reaction {sup 208}Pb({sup 50}Ti, 1n){sup 257}Rf with 237-MeV beam energy on target, separated in the Berkeley Gas-filled Separator (BGS) and transferred to a gas jet using the Recoil Transfer Chamber (RTC). The activity delivered by the gas jet was dissolved in 6-M HNO{sub 3} and Rf was extracted into 0.25-M dibutyl-phosphoric acid in toluene. This was the first time a transactinide, i.e., an element with Z{>=}104, was extracted and unequivocally identified by the SISAK system. Thus, this pilot experiment demonstrates that the fast liquid-liquid extraction system SISAK, in combination with liquid-scintillation detectors, can be used for investigating the chemical properties of the transactinides. The extraction result is in accordance with the behaviour shown by the Rf group IV homologues Zr and Hf. (author)

Interfacial transport characteristics in a gas-liquid or an immiscible liquid-liquid stratified flow

International Nuclear Information System (INIS)

Inoue, A.; Aoki, S.; Aritomi, M.; Kozawa, Y.

1982-01-01

This paper is a review for an interfacial transport characteristics of mass, momentum and energy in a gas-liquid or a immiscible liquid-liquid stratified flow with wavy interface which have been studied in our division. In the experiment, a characteristic of wave motion and its effect to the turbulence near the interface as well as overall flow characteristics like pressure drop, position of the interface were investigated in an air-water, an air-mercury and a water-liquid metal stratified flow. On the other hand, several models based on the mixing length model and a two-equation model of turbulence, with special interfacial boundary conditions in which the wavy surface was regarded as a rough surface correspond to the wavy height, a source of turbulent energy equal to the wave energy and a damped-turbulence due to the surface tension, were proposed to predict the flow characteristics and the interfacial heat transfer in a fully developed and an undeveloped stratified flow and examined by the experimental data. (author)

Liquid helium target

International Nuclear Information System (INIS)

Fujii, Y.; Kitami, T.; Torikoshi, M.

1984-12-01

A liquid helium target system has been built and used for the experiment on the reaction 4 He(γ, p). The target system has worked satisfactorily; the consumption rate of liquid helium is 360 ml/h and the cryogenic system retains liquid helium for about ten hours. The structure, operation and performance of the target system are reported. (author)

Comparison of dispersive liquid-liquid microextraction and hollow fiber liquid-liquid-liquid microextraction for the determination of fentanyl, alfentanil, and sufentanil in water and biological fluids by high-performance liquid chromatography.

Science.gov (United States)

Saraji, Mohammad; Khalili Boroujeni, Malihe; Hajialiakbari Bidgoli, Ali Akbar

2011-06-01

Dispersive liquid-liquid microextraction (DLLME) and hollow fiber liquid-liquid-liquid microextraction (HF-LLLME) combined with HPLC-DAD have been applied for the determination of three narcotic drugs (alfentanil, fentanyl, and sufentanil) in biological samples (human plasma and urine). Different DLLME parameters influencing the extraction efficiency such as type and volume of the extraction solvent and the disperser solvent, concentration of NaOH, and salt addition were investigated. In the HF-LLLME, the effects of important parameters including organic solvent type, concentration of NaOH as donor solution, concentration of H(2)SO(4) as acceptor phase, salt addition, stirring rate, temperature, and extraction time were investigated and optimized. The results showed that both extraction methods exhibited good linearity, precision, enrichment factor, and detection limit. Under optimal condition, the limits of detection ranged from 0.4 to 1.9 μg/L and from 1.1 to 2.3 μg/L for DLLME and HF-LLLME, respectively. For DLLME, the intra- and inter-day precisions were 1.7-6.4% and 14.2-15.9%, respectively; and for HF-LLLME were 0.7-5.2% and 3.3-10.1%, respectively. The enrichment factors were from 275 to 325 and 190 to 237 for DLLME and HF-LLLME, respectively. The applicability of the proposed methods was investigated by analyzing biological samples. For analysis of human plasma and urine samples, HF-LLLME showed higher precision, more effective sample clean-up, higher extraction efficiency, lower organic solvent consumption than DLLME.

Microsystems for liquid-liquid extraction of radionuclides in the analytical protocols

International Nuclear Information System (INIS)

Helle, Gwendolyne

2014-01-01

Radiochemical analyses are necessary to numerous steps for nuclear wastes management and for the control of the environment. An analytical protocol generally includes different steps of chemical separations which are lengthy, manual and complicated to implement because of their confinement in glove boxes and because of the hostile chemical and radiochemical media. Thus there is a huge importance to propose innovative and robust solutions to automate these steps but also to reduce the volumes of the radioactive and chemical wastes at the end of the analytical cycle. One solution consists in the miniaturization of the analyses through the use of lab-on-chip. The objective of this thesis work was to propose a rational approach to the conception of separative microsystems for the liquid-liquid extraction of radionuclides. To achieve this, the hydrodynamic behavior as well as the extraction performances have been investigated in one chip for three different chemical systems: Eu(III)-HNO 3 /DMDBTDMA, Eu(III)-AcO(H,Na)-HNO 3 /HDEHP and U(VI)-HCl/Aliquat336. A methodology has been developed for the implementation of the liquid-liquid extraction in micro-system for each chemical system. The influence of various geometric parameters such as channel length or specific interfacial area has been studied and the comparison of the liquid-liquid extraction performances has led to highlight the influence of the phases viscosities ratio on the flows. Thanks to the modeling of both hydrodynamics and mass transfer in micro-system, the criteria related to physical and kinetic properties of the chemical systems have been distinguished to propose a rational conception of tailor-made chips. Finally, several examples of the liquid-liquid extraction implementation in micro-system have been described for analytical applications in the nuclear field: U/Co separation by Aliquat336, Eu/Sm separation by DMDBTDMA or even the coupling between a liquid-liquid extraction chip and the system of

Application of ionic liquids in liquid chromatography and electrodriven separation.

Science.gov (United States)

Huang, Yi; Yao, Shun; Song, Hang

2013-08-01

Ionic liquids (ILs) are salts in the liquid state at ambient temperature, which are nonvolatile, nonflammable with high thermal stability and dissolve easily for a wide range of inorganic and organic materials. As a kind of potential green solvent, they show high efficiency and selectivity in the field of separation research, especially in instrumental analysis. Thus far, ILs have been successfully applied by many related researchers in high-performance liquid chromatography and capillary electrophoresis as chromatographic stationary phases, mobile phase additives or electroosmotic flow modifiers. This paper provides a detailed review of these applications in the study of natural products, foods, drugs and other fine chemicals. Furthermore, the prospects of ILs in liquid chromatographic and electrodriven techniques are discussed.

Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

Science.gov (United States)

Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

2015-09-01

In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetomotive room temperature dicationic ionic liquid: a new concept toward centrifuge-less dispersive liquid-liquid microextraction.

Science.gov (United States)

Beiraghi, Asadollah; Shokri, Masood; Seidi, Shahram; Godajdar, Bijan Mombani

2015-01-09

A new centrifuge-less dispersive liquid-liquid microextraction technique based on application of magnetomotive room temperature dicationic ionic liquid followed by electrothermal atomic absorption spectrometry (ETAAS) was developed for preconcentration and determination of trace amount of gold and silver in water and ore samples, for the first time. Magnetic ionic liquids not only have the excellent properties of ionic liquids but also exhibit strong response to an external magnetic field. These properties provide more advantages and potential application prospects for magnetic ionic liquids than conventional ones in the fields of extraction processes. In this work, thio-Michler's ketone (TMK) was used as chelating agent to form Ag/Au-TMK complexes. Several important factors affecting extraction efficiency including extraction time, rate of vortex agitator, pH of sample solution, concentration of the chelating agent, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) were 3.2 and 7.3ngL(-1) with the preconcentration factors of 245 and 240 for Au and Ag, respectively. The precision values (RSD%, n=7) were 5.3% and 5.8% at the concentration level of 0.05μgL(-1) for Au and Ag, respectively. The relative recoveries for the spiked samples were in the acceptable range of 96-104.5%. The results demonstrated that except Hg(2+), no remarkable interferences are created by other various ions in the determination of Au and Ag, so that the tolerance limits (WIon/WAu or Ag) of major cations and anions were in the range of 250-1000. The validated method was successfully applied for the analysis of Au and Ag in some water and ore samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of anthraquinones in Rheum palmatum L.

Science.gov (United States)

Wang, Zhibing; Hu, Jianxue; Du, Hongxia; He, Shuang; Li, Qing; Zhang, Hanqi

2016-06-05

The microwave-assisted ionic liquid homogeneous liquid-liquid microextraction (MA-IL-HLLME) coupled with high performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of anthraquinones, including aloe-emodin, emodin, chrysophanol and physcion in root of Rheum palmatum L. Several experimental parameters influencing the extraction efficiency, including amount of sample, type and volume of ionic liquid, volume and pH value of extraction medium, microwave power and extraction time, concentration of NH4PF6 as well as centrifugal condition were optimized. When 140μL of ionic liquid ([C8MIM][BF4]) was used as an extraction solvent, target analytes can be extracted from sample matrix in one minute with the help of microwave irradiation. The MA-IL-HLLME is simple and quick. The calibration curves exhibited good linear relationship (r>0.9984). The limits of detection and quantification were in the range of 0.015-0.026 and 0.051-0.088μgmL(-1), respectively. The spiked recovery for each analyte was in the range of 81.13-93.07% with relative standard deviations lower than 6.89%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and heat reflux extraction. The results indicated that the present method can be successfully applied to the determination of anthraquinones in medicinal plant. Copyright © 2016 Elsevier B.V. All rights reserved.

Liquid hydrogen and deuterium targets; Cibles a hydrogene et deuterium liquides

Energy Technology Data Exchange (ETDEWEB)

Bougon, M; Marquet, M; Prugne, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1961-07-01

A description is given of 1) Atmospheric pressure target: liquid hydrogen, 400 mm thickness; thermal insulation: styrofoam; the hydrogen vapors are used to improve the target cooling; Mylar windows. 2) Vacuum target: 12 liter content: hydrogen or deuterium; liquid thickness 400 mm; thermal insulation is afforded by a vacuum vessel and a liquid nitrogen shield. Recovery and liquefaction of deuterium vapors are managed in the vacuum vessel which holds the target. The target emptying system is designed for operating in a few minutes. (author) [French] Description de: 1) Cible a pression atmospherique; hydrogene liquide, 400 mm d'epaisseur; l'isolement thermique: styrofoam; on utilise les vapeurs d'hydrogene pour ameliorer le refroidissement de la cible; hublots en Mylar. 2) Cible sous vide; contenance 12 litres; hydrogene ou deuterium; epaisseur du liquide 400 mm; l'isolement thermique est assure par une cuve a vide et un ecran d'azote liquide. Recuperation et liquefaction des vapeurs de deuterium sont effectuees dans la cuve a vide contenant la cible. Le systeme de vidange pour la cible est concu pour fonctionner en quelques minutes. (auteur)

Liquid distribution in trickle-bed reactor; Distribution du liquide en reacteur a lit ruisselant

Energy Technology Data Exchange (ETDEWEB)

Marcandelli, C.; Wild, G. [Centre National de la Recherche Scientifique (CNRS-ENSIC), Lab. des Sciences du Genie Chimique, 54 - Nancy (France); Lamine, A.S. [CNRS-Universite de Paris-Nord, Lab. d' Ingenierie des Materiaux et des Hautes Pressions, 93 - Villetaneuse (France); Bernard, J.R. [Elf Antar France, Centre de Recherche Elf de Solaize, 69 - Solaize (France)

2000-07-01

The aim of this study is to develop techniques to qualify the efficiency of liquid distribution in trickle-bed reactors, using cold mockups. The experimental setup consists mainly in a 0.3-m-ID packed-bed column with three different plates used to vary the quality of inlet liquid distribution. Liquid distribution has been qualified using several techniques: global pressure drop measurements, global RTD (Residence-Time Distribution) of the liquid, local heat transfer probes, capacitance tomography, collector at the bottom of the reactor with nine equal zones. The bed pressure drop and the overall external liquid saturation decrease when the maldistribution increases; quantitative information is however difficult to obtain this way. Global RTD of the liquid allows quantifying of the average liquid distribution in the bed. The local thermal sensors give an indication of local liquid velocity and indicate possible local maldistribution of the liquid (scale mm) even when global distribution is good. Concerning the results obtained with the collector, a maldistribution index is defined ranging from 0 (ideal distribution) to 1 (worst possible distribution), and the influence of the different operating parameters (gas and liquid velocities, particle shape) is discussed. (authors)

Radioactive liquid waste filtering device

International Nuclear Information System (INIS)

Inami, Ichiro; Tabata, Masayuki; Kubo, Koji.

1988-01-01

Purpose: To prevent clogging in filter materials and improve the filtration performance for radioactive liquid wastes without increasing the amount of radioactive wastes. Constitution: In a radioactive waste filtering device, a liquid waste recycling pipe and a liquid recycling pump are disposed for recycling the radioactive liquid wastes in a liquid wastes vessel. In this case, the recycling pipe and the recycling pump are properly selected so as to satisfy the conditions capable of making the radioactive liquid wastes flowing through the pipe to have the Reynolds number of 10 4 - 10 5 . By repeating the transportation of radioactive liquid wastes in the liquid waste vessel through the liquid waste recycling pipe by the liquid waste recycling pump and then returning them to the liquid waste vessel again, particles of fine grain size in the suspended liquids are coagulated with each other upon collision to increase the grain size of the suspended particles. In this way, clogging of the filter materials caused by the particles of fine grain size can be prevented, thereby enabling to prevent the increase in the rising rate of the filtration differential pressure, reduce the frequency for the occurrence of radioactive wastes such as filter sludges and improve the processing performance. (Kamimura, M.)

Numerical modeling of liquid feeding in the liquid-fed ceramic melter

International Nuclear Information System (INIS)

Hjelm, R.L.; Donovan, T.E.

1979-10-01

A modeling scheme developed by the Pacific Northwest Laboratory numerically simulates the behavior of the Liquid-Fed Ceramic Melter (LFCM) during liquid feeding. The computer code VECTRA (Vorticity Energy Code for TRansport Analysis) was used to simulate the LFCM in the idling and liquid feeding modes. Results for each simulation include molten glass temperature profiles and isotherm contour plots, stream function contour plots, heat generation rate contour plots, refractory isotherms, and heat balances. The results indicated that the model showed no major deviations from real LFCM behavior and that high throughput should be attainable. They also indicated that reboil was a possibility as a steady liquid feeding state was approached, very steep temperature gradients exist in the Monofrax K-3, and that phase separation could occur in the bottom corners during liquid feeding and over the entire floor while idling

Remotely controllable liquid marbles

KAUST Repository

Zhang, Lianbin; Cha, Dong Kyu; Wang, Peng

2012-01-01

Liquid droplets encapsulated by self-organized hydrophobic particles at the liquid/air interface - liquid marbles - are prepared by encapsulating water droplets with novel core/shell-structured responsive magnetic particles, consisting of a

The risk components of liquidity

OpenAIRE

Chollete, Lorán; Næs, Randi; Skjeltorp, Johannes A.

2008-01-01

Does liquidity risk differ depending on our choice of liquidity proxy? Unlike literature that considers common liquidity variation, we focus on identifying different components of liquidity, statistically and economically, using more than a decade of US transaction data. We identify three main statistical liquidity factors which are utilized in a linear asset pricing framework. We motivate a correspondence of the statistical factors to traditional dimensions of liquidity as well as the notion...

Hydrogen extraction from liquid lithium-lead alloy by gas-liquid contact method

International Nuclear Information System (INIS)

Xie Bo; Weng Kuiping; Hou Jianping; Yang Guangling; Zeng Jun

2013-01-01

Hydrogen extraction experiment from liquid lithium-lead alloy by gas-liquid contact method has been carried out in own liquid lithium-lead bubbler (LLLB). Experimental results show that, He is more suitable than Ar as carrier gas in the filler tower. The higher temperature the tower is, the greater hydrogen content the tower exports. Influence of carrier gas flow rate on the hydrogen content in the export is jagged, no obvious rule. Although the difference between experimental results and literature data, but it is feasible that hydrogen isotopes extraction experiment from liquid lithium-lead by gas-liquid contact method, and the higher extraction efficiency increases with the growth of the residence time of the alloy in tower. (authors)

The liquidity management of institutional investors and the pricing of liquidity risk

NARCIS (Netherlands)

Xing, Ran

2016-01-01

This dissertation studies how mutual funds and hedge funds manage their liquidity and reduce trading costs, and the pricing of liquidity level and liquidity risk in financial markets. Chapter 1 documents the trading behavior of actively managed equity mutual funds from the perspective of their

Recovering volatile liquids

Energy Technology Data Exchange (ETDEWEB)

Bregeat, J H

1925-07-30

The products of hydrogenation of alicyclic compounds, such as terpenes, for example, pinene or oil of turpentine, are used as washing liquids for absorbing vapours of volatile liquids from gases, such as natural gases from petroliferous regions, gases from the distillation of coal, lignite, schist, peat, etc. or from the cracking of heavy oils. Other liquids such as tar oils vaseline oils, cresols, etc. may be added.

Screen Channel Liquid Acquisition Device Outflow Tests in Liquid Hydrogen

Science.gov (United States)

Hartwig, Jason W.; Chato, David J.; McQuillen, J. B.; Vera, J.; Kudlac, M. T.; Quinn, F. D.

2013-01-01

This paper presents experimental design and test results of the recently concluded 1-g inverted vertical outflow testing of two 325x2300 full scale liquid acquisition device (LAD) channels in liquid hydrogen (LH2). One of the channels had a perforated plate and internal cooling from a thermodynamic vent system (TVS) to enhance performance. The LADs were mounted in a tank to simulate 1-g outflow over a wide range of LH2 temperatures (20.3 - 24.2 K), pressures (100 - 350 kPa), and flow rates (0.010 - 0.055 kg/s). Results indicate that the breakdown point is dominated by liquid temperature, with a second order dependence on mass flow rate through the LAD. The best performance is always achieved in the coldest liquid states for both channels, consistent with bubble point theory. Higher flow rates cause the standard channel to break down relatively earlier than the TVS cooled channel. Both the internal TVS heat exchanger and subcooling the liquid in the propellant tank are shown to significantly improve LAD performance.

Study of liquid hydrogen and liquid deuterium cold neutron sources

International Nuclear Information System (INIS)

Harig, H.D.

1969-01-01

In view of the plant of the cold neutron source for a high flux reactor (maximal thermal flux of about 10 15 n/cm 2 s) an experimental study of several cold sources of liquid hydrogen and liquid deuterium has been made in a low power reactor (100 kW, about 10 12 n/cm 2 s). We have investigated: -cold neutron sources of liquid hydrogen shaped as annular layers of different thickness. Normal liquid hydrogen was used as well as hydrogen with a high para-percentage. -Cold neutron sources of liquid deuterium in cylinders of 18 and 38 cm diameter. In this case the sources could be placed into different positions to the reactor core within the heavy water reflector. This report gives a general description of the experimental device and deals more detailed with the design of the cryogenic systems. Then, the measured results are communicated, interpreted and finally compared with those of a theoretical study about the same cold moderators which have been the matter of the experimental investigation. (authors) [fr

Illiquidity Contagion and Liquidity Crashes

OpenAIRE

Giovanni Cespa; Thierry Foucault

2014-01-01

Liquidity providers often learn information about an asset from prices of other assets. We show that this generates a self-reinforcing positive relationship between price informativeness and liquidity. This relationship causes liquidity spillovers and is a source of fragility: a small drop in the liquidity of one asset can, through a feedback loop, result in a very large drop in market liquidity and price informativeness (a liquidity crash). This feedback loop provides a new explanation for c...

Liquidity Runs

NARCIS (Netherlands)

Matta, R.; Perotti, E.

2016-01-01

Can the risk of losses upon premature liquidation produce bank runs? We show how a unique run equilibrium driven by asset liquidity risk arises even under minimal fundamental risk. To study the role of illiquidity we introduce realistic norms on bank default, such that mandatory stay is triggered

Erasing no-man's land by thermodynamically stabilizing the liquid-liquid transition in tetrahedral particles

NARCIS (Netherlands)

Smallenburg, Frank; Filion, Laura|info:eu-repo/dai/nl/326823484; Sciortino, Francesco

2014-01-01

One of the most controversial hypotheses for explaining the origin of the thermodynamic anomalies characterizing liquid water postulates the presence of a metastable second-order liquid-liquid critical point located in the 'no-man's land'. In this scenario, two liquids with distinct local structure

Erasing no-man's land by thermodynamically stabilizing the liquid-liquid transition in tetrahedral particles.

Science.gov (United States)

Smallenburg, Frank; Filion, Laura; Sciortino, Francesco

2014-09-01

One of the most controversial hypotheses for explaining the origin of the thermodynamic anomalies characterizing liquid water postulates the presence of a metastable second-order liquid-liquid critical point [1] located in the "no-man's land" [2]. In this scenario, two liquids with distinct local structure emerge near the critical temperature. Unfortunately, since spontaneous crystallization is rapid in this region, experimental support for this hypothesis relies on significant extrapolations, either from the metastable liquid or from amorphous solid water [3, 4]. Although the liquid-liquid transition is expected to feature in many tetrahedrally coordinated liquids, including silicon [5], carbon [6] and silica, even numerical studies of atomic and molecular models have been unable to conclusively prove the existence of this transition. Here we provide such evidence for a model in which it is possible to continuously tune the softness of the interparticle interaction and the flexibility of the bonds, the key ingredients controlling the existence of the critical point. We show that conditions exist where the full coexistence is thermodynamically stable with respect to crystallization. Our work offers a basis for designing colloidal analogues of water exhibiting liquid-liquid transitions in equilibrium, opening the way for experimental confirmation of the original hypothesis.

Removal of Radioactive Pollutants by Liquid Emulsion Membrane From Liquid Waste

International Nuclear Information System (INIS)

Yossef, Y.A.A.

2013-01-01

Radioactive liquid waste should be safely managed because it is potentially hazardous to human health and the environment. Several methods were used for treatment of liquid waste, such as liquid emulsion membrane (LEM). In this work, liquid emulsion membrane using Tri-butyl phosphate (TBP) plus Bis (2-ethylhexyl) phosphate (HDEHP) as mobile carriers, hydrochloric acid (HCl) as stripping agents and an emulsifying agent (span 80) was used for the extraction of uranium ions from radioactive liquid waste. Various parameters influencing the permeation of uranium ions through the membrane have been optimized to separate uranium ions from radioactive liquid waste such as: the effects of membrane material, carrier concentration, operating conditions, etc. were examined; moreover, the transport mechanism of this uranium was also studied. The internal mass transfer in the water/oil (W/O) emulsion drop, the external mass transfer around the drop, the rates of formation, and the decomposition of the complex at the external aqueous-organic interface were considered. The results show that, the liquid emulsion membrane which consists of (25% by volume HDEHP, 0.005 M + 75% by volume TBP, 0.01 M) as extractant (carrier), span 80, 4% (v/v) (sorbitan monooleate) as surfactant agent, hydrochloric acid (HCl), (1.0 M) as stripping agent. From the results, the maximum extraction percent of uranium ions (nearly about of 100%) occurred at the operating conditions: stirring speed =500 rpm, the ratio between LEM and feed phase (liquid waste) = 20 ml: 100 ml, the ratio between organic phase (membrane phase) to internal aqueous phase (stripping phase) = 1.0 and the ph value of the external aqueous phase equal to 5.0.

Numerical investigation on liquid sheets interaction characteristics of liquid-liquid coaxial swirling jets in bipropellant thruster

International Nuclear Information System (INIS)

Ding, Jia-Wei; Li, Guo-Xiu; Yu, Yu-Song

2016-01-01

Highlights: • A LES-VOF model is conducted to simulate atomization of coaxial swirling jets. • Structure and flow field of coaxial swirling jets are investigated. • Merging process occurs at the nozzle exit and generates additional perturbation. • The Rayleigh mode instability dominates the breakup of ligaments. - Abstract: Spray atomization process of a liquid-liquid coaxial swirl injector in bipropellant thruster has been investigated using volume of fluid (VOF) method coupled with large eddy simulation methodology. With fine grid resolution, detailed flow field of interacted liquid sheet has been captured and analyzed. For coaxial swirling jet, static pressure drop in the region between the liquid sheets makes two liquid sheets to approach each other and merge. A strong pressure, velocity and turbulent fluctuations are calculated near the contact position of two coaxial jets. Simulation results indicate that additional perturbations are generated due to strong radial and axial shear effects between coaxial jets. Observation of droplet formation process reveals that the Rayleigh mode instability dominates the breakup of the ligament. Droplet diameter and distribution have been investigated quantitatively. The mean diameter of the coaxial jets is between that of the inner and the outer jets. Compared with the individual swirling jets, wider size distributions of droplets are produced in the coaxial jets.

Curvature dependence of the electrolytic liquid-liquid interfacial tension

NARCIS (Netherlands)

Bier, Markus; de Graaf, J.; Zwanikken, J.W.; van Roij, R.H.H.G.

2009-01-01

The interfacial tension of a liquid droplet surrounded by another liquid in the presence of microscopic ions is studied as a function of the droplet radius. An analytical expression for the interfacial tension is obtained within a linear Poisson–Boltzmann theory and compared with numerical results

Ionic liquid based dispersive liquid-liquid microextraction for the extraction of pesticides from bananas.

Science.gov (United States)

Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Asensio-Ramos, María; Rodríguez-Delgado, Miguel Angel

2009-10-23

This paper describes a dispersive liquid-liquid microextraction (DLLME) procedure using room temperature ionic liquids (RTILs) coupled to high-performance liquid chromatography with diode array detection capable of quantifying trace amounts of eight pesticides (i.e. thiophanate-methyl, carbofuran, carbaryl, tebuconazole, iprodione, oxyfluorfen, hexythiazox and fenazaquin) in bananas. Fruit samples were first homogenized and extracted (1g) with acetonitrile and after suitable evaporation and reconstitution of the extract in 10 mL of water, a DLLME procedure using 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) as extraction solvent was used. Experimental conditions affecting the DLLME procedure (sample pH, sodium chloride percentage, ionic liquid amount and volume of disperser solvent) were optimized by means of an experimental design. In order to determine the presence of a matrix effect, calibration curves for standards and fortified banana extracts (matrix matched calibration) were studied. Mean recovery values of the extraction of the pesticides from banana samples were in the range of 69-97% (except for thiophanate-methyl and carbofuran, which were 53-63%) with a relative standard deviation lower than 8.7% in all cases. Limits of detection achieved (0.320-4.66 microg/kg) were below the harmonized maximum residue limits established by the European Union (EU). The proposed method, was also applied to the analysis of this group of pesticides in nine banana samples taken from the local markets of the Canary Islands (Spain). To the best of our knowledge, this is the first application of RTILs as extraction solvents for DLLME of pesticides from samples different than water.

SISAK liquid-liquid extraction experiments with preseparated 257Rf

International Nuclear Information System (INIS)

Omtvedt, Jon Petter; Alstad, J.; Breivik, H.; Dyve, J.E.; Eberhardt, K.; Folden III, C.M.; Ginter, T.; Gregorich, K.E.; Hult, E.A.; Johansson, M.; Kirbach, U.W.; Lee, D.M.; Mendel, M.; Nahler, A.; Ninov, V.; Omtvedt, L.A.; Patin, J.B.; Skarnemark, G.; Stavsetra, L.; Sudowe, R.; Wiehl, N.; Wierczinski, B.; Wilk, P.A.; Zielinski, P.M.; Kratz, J.V.; Trautmann, N.; Nitsche, H.; Hoffman, D.C.

2002-01-01

The SISAK liquid-liquid extraction system was used to extract 4.0-s 257Rf. The 257Rf was produced in the reaction 208Pb(50Ti, 1n)257Rf with 237-MeV beam energy on target, separated in the Berkeley Gas-filled Separator (BGS) and transferred to a gas jet using the Recoil Transfer Chamber (RTC). The activity delivered by the gas jet was dissolved in 6-M HNO3 and Rf was extracted into 0.25-M dibutyl-phosphoric acid in toluene. This was the first time a transactinide, i.e., an element with Z >= 104, was extracted and unequivocally identified by the SISAK system. Thus, this pilot experiment demonstrates that the fast liquid-liquid extraction system SISAK, in combination with liquidscintillation detectors, can be used for investigating the chemical properties of the transactinides. The extraction result is in accordance with the behaviour shown by the Rf group IV homologues Zr and Hf

Haze Formation and Behavior in Liquid-Liquid Extraction Processes

International Nuclear Information System (INIS)

Arm, Stuart T.; Jenkins, J. A.

2006-01-01

Aqueous haze formation and behavior was studied in the liquid-liquid system tri-n-butyl phosphate in odorless kerosene and 3M nitric acid with uranyl nitrate and cesium nitrate representing the major solute and an impurity, respectively. A pulsed column, mixer-settler and centrifugal contactor were chosen to investigate the effect of different turbulence characteristics on the manifestation of haze since these contactors exhibit distinct mixing phenomena. The dispersive processes of drop coalescence and breakage, and water precipitation in the organic phase were observed to lead to the formation of haze drops of ∼1 um in diameter. The interaction between the haze and primary drops of the dispersion was critical to the separation efficiency of the liquid-liquid extraction equipment. Conditions of high power input and spatially homogeneous mixing enabled the haze drops to become rapidly assimilated within the dispersion to maximize the scrub performance and separation efficiency of the equipment

The Liquid Hand-to-Mouth

DEFF Research Database (Denmark)

Olafsson, Arna; Pagel, Michaela

constraints. To that end, we analyze cash-holding responses to income payments inspired by the corporate finance literature. However, we find that individuals’ cash responses are consistent with standard models without illiquid savings, and neither present nor future liquidity constraints being frequently...... and spending categories throughout the income distribution. Spending responses to income are typically explained by households’ capital structures. Households that hold little or no liquid wealth have to consume hand-to-mouth. However, we find that few individuals hold little or no liquidity, and we report...... that liquidity holdings are much larger than predicted by state-of-the-art models that explain spending responses with liquidity constraints due to illiquid savings. Given that present liquidity constraints do not bind, we analyze whether individuals hold liquidity cushions to cope with future liquidity...

Detection of Organophosphorus Pesticides in Wheat by Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction Combined with HPLC

Directory of Open Access Journals (Sweden)

Wei Liu

2018-01-01

Full Text Available Food safety issues closely related to human health have always received widespread attention from the world society. As a basic food source, wheat is the fundamental support of human survival; therefore, the detection of pesticide residues in wheat is very necessary. In this work, the ultrasonic-assisted ionic liquid-dispersive liquid-liquid microextraction (DLLME method was firstly proposed, and the extraction and analysis of three organophosphorus pesticides were carried out by combining high-performance liquid chromatography (HPLC. The extraction efficiencies of three ionic liquids with bis(trifluoromethylsulfonylimide (Tf2N anion were compared by extracting organophosphorus in wheat samples. It was found that the use of 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonylimide ([OMIM][Tf2N] had both high enrichment efficiency and appropriate extraction recovery. Finally, the method was used for the determination of three wheat samples, and the recoveries of them were 74.8–112.5%, 71.8–104.5%, and 83.8–115.5%, respectively. The results show that the method proposed is simple, fast, and efficient, which can be applied to the extraction of organic matters in wheat samples.

Quantum liquids get thin

Science.gov (United States)

Ferrier-Barbut, Igor; Pfau, Tilman

2018-01-01

A liquid exists when interactions that attract its constituent particles to each other are counterbalanced by a repulsion acting at higher densities. Other characteristics of liquids are short-range correlations and the existence of surface tension (1). Ultracold atom experiments provide a privileged platform with which to observe exotic states of matter, but the densities are far too low to obtain a conventional liquid because the atoms are too far apart to create repulsive forces arising from the Pauli exclusion principle of the atoms' internal electrons. The observation of quantum liquid droplets in an ultracold mixture of two quantum fluids is now reported on page 301 of this issue by Cabrera et al. (2) and a recent preprint by Semeghini et al. (3). Unlike conventional liquids, these liquids arise from a weak attraction and repulsive many-body correlations in the mixtures.

Extraction of toluene from aliphatic compounds using an ionic liquid as solvent: Influence of the alkane on the (liquid + liquid) equilibrium

International Nuclear Information System (INIS)

Gonzalez, Emilio J.; Calvar, Noelia; Dominguez, Irene; Dominguez, Angeles

2011-01-01

Research highlights: → An ionic liquid was analyzed as solvent for extraction of toluene from alkanes. → Liquid-liquid equilibrium data were measured at 298.15 K and atmospheric pressure. → Selectivity and solute distribution ratio were obtained and compared with literature. → The Othmer-Tobias equation was used to ascertain the experimental LLE data. → Experimental data were correlated using NRTL and UNIQUAC models. - Abstract: In this paper, the feasibility of using 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid, [EMim][ESO 4 ], as solvent for the extraction of toluene from aliphatic compounds (hexane, heptane, octane, or nonane) was analyzed. (Liquid + liquid) equilibrium (LLE) data for the ternary systems {alkane (1) + toluene (2) + [EMim][ESO 4 ] (3)} were measured at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio were calculated from the experimental LLE data, and the obtained values were compared to those previously reported using other ionic liquids and sulfolane. The degree of consistency of the experimental LLE data was ascertained using the Othmer-Tobias equation. Finally, the experimental LLE data were satisfactorily correlated with NRTL and UNIQUAC models.

(Liquid + liquid) equilibria for (water + 1-propanol or acetone + β-citronellol) at different temperatures

International Nuclear Information System (INIS)

Li, Hengde; Han, Yongtao; Huang, Cheng; Yang, Chufen

2015-01-01

Graphical abstract: (Liquid + liquid) equilibrium data for systems composed of β-citronellol and aqueous 1-propanol or acetone are presented. Distribution ratios of 1-propanol and acetone in the mixtures are examined. The effect of the temperature on the ternary (liquid + liquid) equilibria is evaluated and discussed. - Highlights: • Ternary (liquid + liquid) equilibria containing β-citronellol are presented. • Distribution ratios of 1-propanol and acetone in the mixtures are examined. • The effect on the temperature of the systems is evaluated and discussed. - Abstract: On this paper, experimental (liquid + liquid) equilibrium (LLE) results are presented for systems composed of β-citronellol and aqueous 1-propanol or acetone. To evaluate the phase separation properties of β-citronellol in aqueous mixtures, LLE values for the ternary systems (water + 1-propanol + β-citronellol) and (water + acetone + β-citronellol) were determined with a tie-line method at T = (283.15, 298.15, and 313.15 ± 0.02) K and atmospheric pressure. The reliability of the experimental tie-lines was verified by the Hand and Bachman equations. Ternary phase diagrams, distribution ratios of 1-propanol and acetone in the mixtures are shown. The effect of the temperature on the ternary (liquid + liquid) equilibria was examined and discussed. The experimental LLE values were satisfactorily correlated by extended UNIQUAC and modified UNIQUAC models

Integrated liquid-core optical fibers for ultra-efficient nonlinear liquid photonics.

Science.gov (United States)

Kieu, K; Schneebeli, L; Norwood, R A; Peyghambarian, N

2012-03-26

We have developed a novel integrated platform for liquid photonics based on liquid core optical fiber (LCOF). The platform is created by fusion splicing liquid core optical fiber to standard single-mode optical fiber making it fully integrated and practical - a major challenge that has greatly hindered progress in liquid-photonic applications. As an example, we report here the realization of ultralow threshold Raman generation using an integrated CS₂ filled LCOF pumped with sub-nanosecond pulses at 532 nm and 1064 nm. The measured energy threshold for the Stokes generation is 1nJ, about three orders of magnitude lower than previously reported values in the literature for hydrogen gas, a popular Raman medium. The integrated LCOF platform opens up new possibilities for ultralow power nonlinear optics such as efficient white light generation for displays, mid-IR generation, slow light generation, parametric amplification, all-optical switching and wavelength conversion using liquids that have orders of magnitude larger optical nonlinearities compared with silica glass.

On the abundance and general nature of the liquid-liquid phase transition in molecular systems

International Nuclear Information System (INIS)

Kurita, Rei; Tanaka, Hajime

2005-01-01

Even a single-component liquid may have more than two kinds of isotropic liquid states. The transition between these different states is called a liquid-liquid transition (LLT). An LLT has been considered to be a rather rare phenomenon, in particular for molecular liquids. Very recently, however, we found an LLT in triphenyl phosphite, which may be the first experimental observation of an LLT for molecular liquids. Here we report convincing evidence of the second example of LLT for another molecular liquid, n-butanol. Despite large differences in the chemical structure and the molecular shape between triphenyl phosphite and n-butanol, the basic features of the transformation kinetics are strikingly similar. This suggests that an LLT may not be a rare phenomenon restricted to specific liquids, but may exist in various molecular liquids, which have a tendency to form long-lived locally favoured structures due to anisotropic interactions (e.g., hydrogen bonding). (letter to the editor)

Liquid crystalline order in polymers

CERN Document Server

Blumstein, Alexandre

1978-01-01

Liquid Crystalline Order in Polymers examines the topic of liquid crystalline order in systems containing rigid synthetic macromolecular chains. Each chapter of the book provides a review of one important area of the field. Chapter 1 discusses scattering in polymer systems with liquid crystalline order. It also introduces the field of liquid crystals. Chapter 2 treats the origin of liquid crystalline order in macromolecules by describing the in-depth study of conformation of such macromolecules in their unassociated state. The chapters that follow describe successively the liquid crystalli

Alkylsulfate-based ionic liquids in the liquid–liquid extraction of aromatic hydrocarbons

International Nuclear Information System (INIS)

García, Silvia; Larriba, Marcos; García, Julián; Torrecilla, José S.; Rodríguez, Francisco

2012-01-01

Highlights: ► Values of α 2,1 for the four R-SO 4 ionic liquids are higher than those of sulfolane. ► Values of D 2 for all the ionic liquids are lower than those of sulfolane. ► Values of D 2 for [emim][C 2 H 5 SO 4 ] are the highest among the R-SO 4 ionic liquids. - Abstract: The (liquid + liquid) equilibrium data (LLE) for the extraction of toluene from heptane with different ionic liquids (ILs) based on the alkylsulfate anion (R-SO 4 ) was determined at T = 313.2 K and atmospheric pressure. The effect of more complex R-SO 4 anions on capacity of extraction and selectivity in the liquid–liquid extraction of toluene from heptane was studied. The ternary systems were formed by {heptane + toluene + 1,3-dimethylimidazolium methylsulfate ([mmim][CH 3 SO 4 ]), 1-ethyl-3-methylimidazolium hydrogensulfate ([emim][HSO 4 ]), 1-ethyl-3-methylimidazolium methylsulfate ([emim][CH 3 SO 4 ]), or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][C 2 H 5 SO 4 ])}. The degree of quality of the experimental LLE data was ascertained by applying the Othmer–Tobias correlation. The phase diagrams for the ternary systems were plotted, and the tie lines correlated with the NRTL model compare satisfactorily with the experimental data.

Some Cavitation Properties of Liquids

Directory of Open Access Journals (Sweden)

K. D. Efremova

2016-01-01

Full Text Available Cavitation properties of liquid must be taken into consideration in the engineering design of hydraulic machines and hydro devices when there is a possibility that in their operation an absolute pressure in the liquid drops below atmospheric one, and for a certain time the liquid is in depression state. Cold boiling, which occurs at a comparatively low temperature under a reduced absolute pressure within or on the surface of the liquid is regarded as hydrostatic cavitation if the liquid is stationary or as hydrodynamic cavitation, if the liquid falls into conditions when in the flow cross-section there is a sharply increasing dynamic pressure and a dropping absolute pressure.In accordance with the theory of cavitation, the first phase of cavitation occurs when the absolute pressure of the degassed liquid drops to the saturated vapour pressure, and the air dissolved in the liquid, leaving the intermolecular space, is converted into micro-bubbles of combined air and becomes a generator of cavitation “nuclei”. A quantitative estimate of the minimum allowable absolute pressure in a real, fully or partially degassed liquid at which a hydrostatic cavitation occurs is of practical interest.Since the pressure of saturated vapour of a liquid is, to a certain extent, related to the forces of intermolecular interaction, it is necessary to have information on the cavitation properties of technical solutions, including air solution in a liquid, as a solute may weaken intermolecular bonds and affect the pressure value of the saturated solvent vapour. In the experiment to carry out vacuum degassing of liquids was used a hydraulic air driven vacuum pump.The paper presents hydrostatic and hydrodynamic degassing liquid processes used in the experiment.The experimental studies of the cavitation properties of technical liquids (sea and distilled water, saturated NaCl solution, and pure glycerol and as a 49/51% solution in water, mineral oil and jet fuel enabled

Mechanism of Lecithin Adsorption at a Liquid/Liquid Interface

Czech Academy of Sciences Publication Activity Database

Mareček, Vladimír; Lhotský, Alexandr; Jänchenová, Hana

2003-01-01

Roč. 107, č. 19 (2003), s. 4573-4578 ISSN 1089-5647 R&D Projects: GA ČR GA203/00/0636 Institutional research plan: CEZ:AV0Z4040901 Keywords : adsorption * mechanism of lecithin * liquid/liquid interface Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.679, year: 2003

The liquidation of liquid radioactive waste on nuclear medicine departments

International Nuclear Information System (INIS)

Fueriova, A.

1995-01-01

The most serious problems for Clinic of Nuclear Medicine of National Oncological Institute, Bratislava (CNM) is the localization of CNM in the downtown, inside the hospital area with the dilution water deficit. This department is the only one in Slovak Republic performing therapeutical applications. To be able to perform the necessary amount of therapies and also to introduce a new therapeutical methods, in 1992-1994 the old liquidation waste disposal station (LWDS) was reconstructed with the aim to satisfy the newest requirements of radiation hygiene. LWDS is the 5-floor object partly underground which satisfied the requirements for liquidation of radioactive liquid waste from diagnostic procedures(annually 5000 patients) and also from 200 therapeutical applications annually (15 beds, 720 GBq iodine-131). The capacity of LWDS is able to store about 90 m 3 liquid radioactive waste. Part of the underground spaces are used for the storage of solid radioactive trash. The liquid waste from CNM is collected through isolated metal sewage system to the storage with continuous observation of water specific activity. According to the activity, the liquid waste is placed to the 5 decay storages with the volume about 15 m 3 . The six one serves for the case of technical accident. When the activity declines, the liquid waste is diluted with non active medical trash to the level which is acceptable by low about radiation hygiene protection. The storage walls are made from barium-concrete 25-50 cm thick which is enough for sufficient protection of operation staff and also for walking around persons. Double-layer high quality chemical material prevents the water leak and diffusion of radionuclides into the concrete. Technology consists of cast-iron drains, powerful slush pumps, operation valves, regulation technology from dosimetric system for continuous monitoring of specific activity, for managing system with powerful industrial computer

The liquidation of liquid radioactive waste on nuclear medicine departments

Energy Technology Data Exchange (ETDEWEB)

Fueriova, A [National Oncological Institue, Bratislava (Slovakia). Hospital St. Elis, Clinic of Nuclear Medicine

1996-12-31

The most serious problems for Clinic of Nuclear Medicine of National Oncological Institute, Bratislava (CNM) is the localization of CNM in the downtown, inside the hospital area with the dilution water deficit. This department is the only one in Slovak Republic performing therapeutical applications. To be able to perform the necessary amount of therapies and also to introduce a new therapeutical methods, in 1992-1994 the old liquidation waste disposal station (LWDS) was reconstructed with the aim to satisfy the newest requirements of radiation hygiene. LWDS is the 5-floor object partly underground which satisfied the requirements for liquidation of radioactive liquid waste from diagnostic procedures(annually 5000 patients) and also from 200 therapeutical applications annually (15 beds, 720 GBq iodine-131). The capacity of LWDS is able to store about 90 m{sup 3} liquid radioactive waste. Part of the underground spaces are used for the storage of solid radioactive trash. The liquid waste from CNM is collected through isolated metal sewage system to the storage with continuous observation of water specific activity. According to the activity, the liquid waste is placed to the 5 decay storages with the volume about 15 m{sup 3}. The six one serves for the case of technical accident. When the activity declines, the liquid waste is diluted with non active medical trash to the level which is acceptable by low about radiation hygiene protection. The storage walls are made from barium-concrete 25-50 cm thick which is enough for sufficient protection of operation staff and also for walking around persons. Double-layer high quality chemical material prevents the water leak and diffusion of radionuclides into the concrete. Technology consists of cast-iron drains, powerful slush pumps, operation valves, regulation technology from dosimetric system for continuous monitoring of specific activity, for managing system with powerful industrial computer.

Behavior of supercooled aqueous solutions stemming from hidden liquid-liquid transition in water.

Science.gov (United States)

Biddle, John W; Holten, Vincent; Anisimov, Mikhail A

2014-08-21

A popular hypothesis that explains the anomalies of supercooled water is the existence of a metastable liquid-liquid transition hidden below the line of homogeneous nucleation. If this transition exists and if it is terminated by a critical point, the addition of a solute should generate a line of liquid-liquid critical points emanating from the critical point of pure metastable water. We have analyzed thermodynamic consequences of this scenario. In particular, we consider the behavior of two systems, H2O-NaCl and H2O-glycerol. We find the behavior of the heat capacity in supercooled aqueous solutions of NaCl, as reported by Archer and Carter [J. Phys. Chem. B 104, 8563 (2000)], to be consistent with the presence of the metastable liquid-liquid transition. We elucidate the non-conserved nature of the order parameter (extent of "reaction" between two alternative structures of water) and the consequences of its coupling with conserved properties (density and concentration). We also show how the shape of the critical line in a solution controls the difference in concentration of the coexisting liquid phases.

Liquid Lithium Limiter Effects on Tokamak Plasmas and Plasma-Liquid Surface Interactions

Energy Technology Data Exchange (ETDEWEB)

R. Kaita; R. Majeski; R. Doerner; G. Antar; M. Baldwin; R. Conn; P. Efthimion; M. Finkenthal; D. Hoffman; B. Jones; S. Krashenninikov; H. Kugel; S. Luckhardt; R. Maingi; J. Menard; T. Munsat; D. Stutman; G. Taylor; J. Timberlake; V. Soukhanovskii; D. Whyte; R. Woolley; L. Zakharov

2002-10-15

We present results from the first experiments with a large area liquid lithium limiter in a magnetic fusion device, and its effect on improving plasma performance by reducing particle recycling. Using large area liquid metal surfaces in any major fusion device is unlikely before a test on a smaller scale. This has motivated its demonstration in the CDX-U spherical torus with a unique, fully toroidal lithium limiter. The highest current discharges were obtained with a liquid lithium limiter. There was a reduction in recycling, as indicated by a significant decrease in the deuterium-alpha emission and oxygen radiation. How these results might extrapolate to reactors is suggested in recycling/retention experiments with liquid lithium surfaces under high-flux deuterium and helium plasma bombardment in PISCES-B. Data on deuterium atoms retained in liquid lithium indicate retention of all incident ions until full volumetric conversion to lithium deuteride. The PISCES-B results also show a material loss mechanism that lowers the maximum operating temperature compared to that for the liquid surface equilibrium vapor pressure. This may restrict the lithium temperature in reactors.

Damping of liquid sloshing by foams: from everyday observations to liquid transport

Science.gov (United States)

Sauret, Alban; Boulogne, Francois; Cappello, Jean; Stone, Howard

2014-11-01

When a liquid-filled container is set in motion, the free surface of the liquid starts to slosh, i.e. oscillate. Such effects can be observed when a glass of water is handled carelessly and the fluid sloshes or even spills over the rim of the container. However, beer does not slosh as readily, which suggests that the presence of foam could be used to damp sloshing. In this work, we study experimentally the effect on sloshing of liquid foam placed on top of a liquid bath in a Hele-Shaw cell. We generate a monodisperse 2D liquid foam and track its motion. The influence of the foam on the sloshing dynamics is characterized: 2 to 3 layers of bubbles are sufficient to significantly damp the oscillations. For more than 5 layers of bubbles, the original vertical motion of the foam becomes mainly horizontal. We rationalize our experimental findings with a model that describes the foam contribution to the damping coefficient. This study motivated by everyday observations has promising applications in numerous industrial applications such as the transport of liquid in cargoes.

Liquid Lithium Limiter Effects on Tokamak Plasmas and Plasma-Liquid Surface Interactions

International Nuclear Information System (INIS)

Kaita, R.; Majeski, R.; Doerner, R.; Antar, G.; Baldwin, M.; Conn, R.; Efthimion, P.; Finkenthal, M.; Hoffman, D.; Jones, B.; Krashenninikov, S.; Kugel, H.; Luckhardt, S.; Maingi, R.; Menard, J.; Munsat, T.; Stutman, D.; Taylor, G.; Timberlake, J.; Soukhanovskii, V.; Whyte, D.; Woolley, R.; Zakharov, L.

2002-01-01

We present results from the first experiments with a large area liquid lithium limiter in a magnetic fusion device, and its effect on improving plasma performance by reducing particle recycling. Using large area liquid metal surfaces in any major fusion device is unlikely before a test on a smaller scale. This has motivated its demonstration in the CDX-U spherical torus with a unique, fully toroidal lithium limiter. The highest current discharges were obtained with a liquid lithium limiter. There was a reduction in recycling, as indicated by a significant decrease in the deuterium-alpha emission and oxygen radiation. How these results might extrapolate to reactors is suggested in recycling/retention experiments with liquid lithium surfaces under high-flux deuterium and helium plasma bombardment in PISCES-B. Data on deuterium atoms retained in liquid lithium indicate retention of all incident ions until full volumetric conversion to lithium deuteride. The PISCES-B results also show a material loss mechanism that lowers the maximum operating temperature compared to that for the liquid surface equilibrium vapor pressure. This may restrict the lithium temperature in reactors

Liquid lithium limiter effects on tokamak plasmas and plasma-liquid surface interactions

International Nuclear Information System (INIS)

Kaita, R.; Majeski, R.; Doerner, R.

2003-01-01

We present results from the first experiments with a large area liquid lithium limiter in a magnetic fusion device, and its effect on improving plasma performance by reducing particle recycling. Using large area liquid metal surfaces in any major fusion device is unlikely before a test on a smaller scale. This has motivated its demonstration in the CDX-U spherical torus with a unique, fully toroidal lithium limiter. The highest current discharges were obtained with a liquid lithium limiter. There was a reduction in recycling, as indicated by a significant decrease in the deuterium-alpha emission and oxygen radiation. How these results might extrapolate to reactors is suggested in recycling/retention experiments with liquid lithium surfaces under high-flux deuterium and helium plasma bombardment in PISCES-B. Data on deuterium atoms retained in liquid lithium indicate retention of all incident ions until full volumetric conversion to lithium deuteride. The PISCES-B results also show a material loss mechanism that lowers the maximum operating temperature compared to that for the liquid surface equilibrium vapor pressure. This may restrict the lithium temperature in reactors. (author)

Erasing no-man’s land by thermodynamically stabilizing the liquid-liquid transition in tetrahedral particles

Science.gov (United States)

Smallenburg, Frank; Filion, Laura; Sciortino, Francesco

2014-09-01

One of the most controversial hypotheses for explaining the origin of the thermodynamic anomalies characterizing liquid water postulates the presence of a metastable second-order liquid-liquid critical point located in the `no-man’s land’. In this scenario, two liquids with distinct local structure emerge near the critical temperature. Unfortunately, as spontaneous crystallization is rapid in this region, experimental support for this hypothesis relies on significant extrapolations, either from the metastable liquid or from amorphous solid water. Although the liquid-liquid transition is expected to feature in many tetrahedrally coordinated liquids, including silicon, carbon and silica, even numerical studies of atomic and molecular models have been unable to conclusively prove the existence of this transition. Here we provide such evidence for a model in which it is possible to continuously tune the softness of the interparticle interaction and the flexibility of the bonds, the key ingredients controlling the existence of the critical point. We show that conditions exist where the full coexistence is thermodynamically stable with respect to crystallization. Our work offers a basis for designing colloidal analogues of water exhibiting liquid-liquid transitions in equilibrium, opening the way for experimental confirmation of the original hypothesis.

Ionic liquids in chemical engineering.

Science.gov (United States)

Werner, Sebastian; Haumann, Marco; Wasserscheid, Peter

2010-01-01

The development of engineering applications with ionic liquids stretches back to the mid-1990s when the first examples of continuous catalytic processes using ionic liquids and the first studies of ionic liquid-based extractions were published. Ever since, the use of ionic liquids has seen tremendous progress in many fields of chemistry and engineering, and the first commercial applications have been reported. The main driver for ionic liquid engineering applications is to make practical use of their unique property profiles, which are the result of a complex interplay of coulombic, hydrogen bonding and van der Waals interactions. Remarkably, many ionic liquid properties can be tuned in a wide range by structural modifications at their cation and anion. This review highlights specific examples of ionic liquid applications in catalysis and in separation technologies. Additionally, the application of ionic liquids as working fluids in process machines is introduced.

Liquid level controller

International Nuclear Information System (INIS)

Mangus, J.D.; Redding, A.H.

1975-01-01

A system for maintaining two distinct sodium levels within the shell of a heat exchanger having a plurality of J-shaped modular tube bundles each enclosed in a separate shell which extends from a common base portion. A lower liquid level is maintained in the base portion and an upper liquid level is maintained in the shell enwrapping the long stem of the J-shaped tube bundles by utilizing standpipes with a notch at the lower end which decreases in open area the distance from the end of the stand pipe increases and a supply of inert gas fed at a constant rate to produce liquid levels, which will remain generally constant as the flow of liquid through the vessel varies

Microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid for the determination of sulfonamides in environmental water samples.

Science.gov (United States)

Song, Ying; Wu, Lijie; Lu, Chunmei; Li, Na; Hu, Mingzhu; Wang, Ziming

2014-12-01

An easy, quick, and green method, microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid, was first developed and applied to the extraction of sulfonamides in environmental water samples. 1-Ethy-3-methylimidazolium hexafluorophosphate, which is a solid-state ionic liquid at room temperature, was used as extraction solvent in the present method. After microwave irradiation for 90 s, the solid-state ionic liquid was melted into liquid phase and used to finish the extraction of the analytes. The ionic liquid and sample matrix can be separated by freezing and centrifuging. Several experimental parameters, including amount of extraction solvent, microwave power and irradiation time, pH of sample solution, and ionic strength, were investigated and optimized. Under the optimum experimental conditions, good linearity was observed in the range of 2.00-400.00 μg/L with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for sulfathiazole, sulfachlorpyridazine, sulfamethoxazole, and sulfaphenazole were 0.39, 0.33, 0.62, and 0.85 μg/L, respectively. When the present method was applied to the analysis of environmental water samples, the recoveries of the analytes ranged from 75.09 to 115.78% and relative standard deviations were lower than 11.89%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid metal cold trap

International Nuclear Information System (INIS)

Hundal, R.

1976-01-01

A cold trap assembly for removing impurities from a liquid metal is described. A hole between the incoming impure liquid metal and purified outgoing liquid metal acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly

INEEL Liquid Effluent Inventory

Energy Technology Data Exchange (ETDEWEB)

Major, C.A.

1997-06-01

The INEEL contractors and their associated facilities are required to identify all liquid effluent discharges that may impact the environment at the INEEL. This liquid effluent information is then placed in the Liquid Effluent Inventory (LEI) database, which is maintained by the INEEL prime contractor. The purpose of the LEI is to identify and maintain a current listing of all liquid effluent discharge points and to identify which discharges are subject to federal, state, or local permitting or reporting requirements and DOE order requirements. Initial characterization, which represents most of the INEEL liquid effluents, has been performed, and additional characterization may be required in the future to meet regulations. LEI information is made available to persons responsible for or concerned with INEEL compliance with liquid effluent permitting or reporting requirements, such as the National Pollutant Discharge Elimination System, Wastewater Land Application, Storm Water Pollution Prevention, Spill Prevention Control and Countermeasures, and Industrial Wastewater Pretreatment. The State of Idaho Environmental Oversight and Monitoring Program also needs the information for tracking liquid effluent discharges at the INEEL. The information provides a baseline from which future liquid discharges can be identified, characterized, and regulated, if appropriate. The review covered new and removed buildings/structures, buildings/structures which most likely had new, relocated, or removed LEI discharge points, and at least 10% of the remaining discharge points.

Effects of microchannel confinement on acoustic vaporisation of ultrasound phase change contrast agents

Science.gov (United States)

Lin, Shengtao; Zhang, Ge; Hau Leow, Chee; Tang, Meng-Xing

2017-09-01

The sub-micron phase change contrast agent (PCCA) composed of a perfluorocarbon liquid core can be activated into gaseous state and form stable echogenic microbubbles for contrast-enhanced ultrasound imaging. It has shown great promise in imaging microvasculature, tumour microenvironment, and cancer cells. Although PCCAs have been extensively studied for different diagnostic and therapeutic applications, the effect of biologically geometrical confinement on the acoustic vaporisation of PCCAs is still not clear. We have investigated the difference in PCCA-produced ultrasound contrast enhancement after acoustic activation with and without a microvessel confinement on a microchannel phantom. The experimental results indicated more than one-order of magnitude less acoustic vaporisation in a microchannel than that in a free environment taking into account the attenuation effect of the vessel on the microbubble scattering. This may provide an improved understanding in the applications of PCCAs in vivo.

Liquid Metal Transformers

OpenAIRE

Sheng, Lei; Zhang, Jie; Liu, Jing

2014-01-01

The room temperature liquid metal is quickly emerging as an important functional material in a variety of areas like chip cooling, 3D printing or printed electronics etc. With diverse capabilities in electrical, thermal and flowing behaviors, such fluid owns many intriguing properties that had never been anticipated before. Here, we show a group of unconventional phenomena occurring on the liquid metal objects. Through applying electrical field on the liquid metals immersed in water, a series...

Liquidity Risk, Liquidity Creation, and Financial Fragility: A Theory of Banking

OpenAIRE

Douglas W. Diamond; Raghuram G. Rajan

2001-01-01

Both investors and borrowers are concerned about liquidity. Investors desire liquidity because they are uncertain about when they will want to eliminate their holding of a financial asset. Borrowers are concerned about liquidity because they are uncertain about their ability to continue to attract or retain funding. Because borrowers typically cannot repay investors on demand, investors will require a premium or significant control rights when they lend to borrowers directly, as compensation ...

Enhanced Detection of Sub-Retinal Pigment Epithelial Cell Layer Deposits in Human and Murine Tissue: Imaging Zinc as a Biomarker for Age-Related Macular Degeneration (An American Ophthalmological Society Thesis).

Science.gov (United States)

van Kuijk, Frederik J G M; McPherson, Scott W; Roehrich, Heidi

2017-08-01

Understanding the apparent paradoxical role of zinc in the pathogenesis and prevention of age-related macular degeneration (AMD) has been limited by the lack of animal models for its detection in sub-retinal epithelial deposits (drusen), a definitive early hallmark of AMD. In-vitro studies using Zinpyr-1 showed drusen contained high levels of zinc, but the probe was not suitable for in-vivo studies. This study compares Zinpyr-1 to ZPP1, a new fluorescein-based probe for zinc, to assess the potential of ZPP1 for in-vivo detection of zinc in drusen. Flat mounts of human sub-RPE tissue using the probes were analyzed by fluorescence and confocal microscopy. Flat mounts of sub-RPE tissue from mice deficient in superoxide dismutase isoform-1 (CuZn-SOD-KO) or isoform-2 (Mn-SOD-RPE-KO) were analyzed with sub-RPE deposits confirmed by histology. Drusen are detected in greater numbers and intensity with ZPP1 compared to Zinpyr-1. Using ZPP1, drusen was detected in a sample from a 46-year old human donor without ocular history, suggesting that ZPP1 might be sensitive enough to detect drusen at an early stage. With CuZn-SOD KO mice, ZPP1 detected sub-RPE deposits at 10 months of age, whereas Zinpyr-1 required 14 months. Detection of sub-RPE deposits by ZPP1 was greatly enhanced compared to Zinpyr-1. This enhanced sensitivity will allow for more insightful analysis of zinc in AMD using human specimens and mouse models. This could result in the development of a sensitive in-vivo probe to enhance research on the role zinc in drusen formation and the early clinical diagnosis of AMD.

Liquid Holding Capacity and Liquid Leakage of Raw Salmon and Trout Fillets

DEFF Research Database (Denmark)

Løje, Hanne; Nielsen, Henrik Hauch; Hyldig, Grethe

2017-01-01

and liquid holding capacity of salmon and trout are influenced by fat content. Liquid leakage did not depend on fat content whereas the liquid holding capacity was lower for fish with high fat content. Thus the methods provide supplementary rather than equal information. Furthermore the water loss part...... was linear depending on liquid loss. The results indicate that fat is more loosely bound in trout than in salmon. These findings may be of immediate relevance to quality control of high-value fat fish products, to assessment of raw material properties, to an efficient treatment in the production...

Detection based on rainbow refractometry of droplet sphericity in liquid-liquid systems.

Science.gov (United States)

Lohner, H; Lehmann, P; Bauckhage, K

1999-03-01

The shape of droplets in liquid-liquid systems influences their mass and momentum transfer processes. The deviation from sphericity of rising droplets in liquid-liquid systems was investigated for different droplet sizes. Rainbow refractometry permits one to test, in this case, whether the use of laser-optical particle sizing will be correct or faulty. Since the assumption of spherical particle geometry is a general basis of laser-optical particle-sizing techniques such as rainbow refractometry or phase Doppler anemometry, deviation from the spherical shape results in a measuring error. A sphericity check based on rainbow refractometry is introduced.

Liquid metal steam generator

International Nuclear Information System (INIS)

Wolowodiuk, W.

1975-01-01

A liquid metal heated steam generator is described which in the event of a tube failure quickly exhausts out of the steam generator the products of the reaction between the water and the liquid metal. The steam is generated in a plurality of bayonet tubes which are heated by liquid metal flowing over them between an inner cylinder and an outer cylinder. The inner cylinder extends above the level of liquid metal but below the main tube sheet. A central pipe extends down into the inner cylinder with a centrifugal separator between it and the inner cylinder at its lower end and an involute deflector plate above the separator so that the products of a reaction between the liquid metal and the water will be deflected downwardly by the deflector plate and through the separator so that the liquid metal will flow outwardly and away from the central pipe through which the steam and gaseous reaction products are exhausted. (U.S.)

Liquidity Determinants of Moroccan Banking Industry

OpenAIRE

FERROUHI, El Mehdi; LEHADIRI, Abderrassoul

2013-01-01

This paper analyzes the behavior of Moroccan bank’s liquidity during the period 2001 – 2012. The research aims to identify the determinants of Moroccan bank’s liquidity. We first evaluate Moroccan banks’ liquidity positions through different liquidity ratios to determine the effects of financial crisis on bank’s liquidity. We then highlight the effect of banks’ size on banks’ liquidity. Finally, we identify determinants of Moroccan bank’s liquidity using panel data regression. ...

The Liquid Hand-to-mouth

DEFF Research Database (Denmark)

Pagel, Michaela; Vardardottir, Arna

liquidity constraints. To that end, we analyze cash holding responses to income payments inspired by the corporate finance literature. However, we find that individuals’ cash responses are consistent with standard models without illiquid savings and neither present nor future liquidity constraints being...... and also document that liquidity holdings are much larger than predicted by state-of-the-art models explaining spending responses with liquidity constraints due to illiquid savings. Given that present liquidity constraints do not bind, we analyze whether individuals hold cash cushions to cope with future...... income and spending categories throughout the income distribution. Spending responses to income are typically explained by households’ capital structures: households that hold little or no liquid wealth have to consume hand-tomouth. However, we find that few individuals hold little or no liquidity...

Remotely controllable liquid marbles

KAUST Repository

Zhang, Lianbin

2012-07-26

Liquid droplets encapsulated by self-organized hydrophobic particles at the liquid/air interface - liquid marbles - are prepared by encapsulating water droplets with novel core/shell-structured responsive magnetic particles, consisting of a responsive block copolymer-grafted mesoporous silica shell and magnetite core (see figure; P2VP-b-PDMS: poly(2-vinylpyridine-b- dimethylsiloxane)). Desirable properties of the liquid marbles include that they rupture upon ultraviolet illumination and can be remotely manipulated by an external magnetic field. 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pesticide extraction from table grapes and plums using ionic liquid based dispersive liquid-liquid microextraction.

Science.gov (United States)

Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Herrera-Herrera, Antonio V; Rodríguez-Delgado, Miguel Angel

2009-12-01

Room temperature ionic liquids (RTILs) have been used as extraction solvents in dispersive liquid-liquid microextraction (DLLME) for the determination of eight multi-class pesticides (i.e. thiophanate-methyl, carbofuran, carbaryl, tebuconazole, iprodione, oxyfluorfen, hexythiazox, and fenazaquin) in table grapes and plums. The developed method involves the combination of DLLME and high-performance liquid chromatography with diode array detection. Samples were first homogenized and extracted with acetonitrile. After evaporation and reconstitution of the extract in water containing sodium chloride, a quick DLLME procedure that used the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) and methanol was developed. The RTIL dissolved in a very small volume of acetonitrile was directed injected in the chromatographic system. The comparison between the calibration curves obtained from standards and from spiked sample extracts (matrix-matched calibration) showed the existence of a strong matrix effect for most of the analyzed pesticides. A recovery study was also developed with five consecutive extractions of the two types of fruits spiked at three concentration levels. Mean recovery values were in the range of 72-100% for table grapes and 66-105% for plum samples (except for thiophanate-methyl and carbofuran, which were 64-75% and 58-66%, respectively). Limits of detection (LODs) were in the range 0.651-5.44 microg/kg for table grapes and 0.902-6.33 microg/kg for plums, representing LODs below the maximum residue limits (MRLs) established by the European Union in these fruits. The potential of the method was demonstrated by analyzing 12 commercial fruit samples (six of each type).

Radiation damage studies on new liquid scintillators and liquid-core scintillating fibers

International Nuclear Information System (INIS)

Golovkin, S.V.

1994-01-01

The radiation resistant of some new liquid scintillation and capillaries filled with liquid scintillators has been presented. It was found that scintillation efficiency of the scintillator based on 1-methyl naphthalene with a new R39 only by 10% at the dose of 190 Mrad and the radiation resistance of thin liquid-core scintillating was decreased fibers exceeded 60 Mrad. 35 refs

Liquidity (risk) concepts: definitions and interactions

OpenAIRE

Nikolaou, Kleopatra

2009-01-01

We discuss the notion of liquidity and liquidity risk within the financial system. We distinguish between three different liquidity types, central bank liquidity, funding and market liquidity and their relevant risks. In order to understand the workings of financial system liquidity, as well as the role of the central bank, we bring together relevant literature from different areas and review liquidity linkages among these three types in normal and turbulent times. We stress that the root of ...

Prediction of vapour-liquid and vapour-liquid-liquid equilibria of nitrogen-hydrocarbon mixtures used in J-T refrigerators

Science.gov (United States)

Narayanan, Vineed; Venkatarathnam, G.

2018-03-01

Nitrogen-hydrocarbon mixtures are widely used as refrigerants in J-T refrigerators operating with mixtures, as well as in natural gas liquefiers. The Peng-Robinson equation of state has traditionally been used to simulate the above cryogenic process. Multi parameter Helmholtz energy equations are now preferred for determining the properties of natural gas. They have, however, been used only to predict vapour-liquid equilibria, and not vapour-liquid-liquid equilibria that can occur in mixtures used in cryogenic mixed refrigerant processes. In this paper the vapour-liquid equilibrium of binary mixtures of nitrogen-methane, nitrogen-ethane, nitrogen-propane, nitrogen-isobutane and three component mixtures of nitrogen-methane-ethane and nitrogen-methane-propane have been studied with the Peng-Robinson and the Helmholtz energy equations of state of NIST REFPROP and compared with experimental data available in the literature.

Binary liquid-liquid equilibria of aniline-paraffin and furfural-paraffin systems

Energy Technology Data Exchange (ETDEWEB)

Sen, S.C.; Maity, S.; Ganguli, K.; Ray, P. (Calcutta Univ., (India))

1991-12-01

Liquid-liquid-equilibria (L-L-E) of hydrocarbon containing systems are of considerable commercial importance to refineries. But prediction of L-L-E of such systems is extremely difficult owing to the complex nature of the petroleum fluids. For treating such complex mixtures, a continuous component method is appropriate and for representing such liquids, a group contribution model like the UNIFAC is extremely convenient. It is, however, necessary to determine the appropriate group interaction parameters, and also to test the applicability of the UNIFAC method to these cases. Binary liquid-liquid-equilibria data for several aniline-paraffin and furfural-paraffin systems have been taken. These data along with data for other aniline-hydrocarbon and furfural-hydrocarbon systems from literature have been correlated using the UNIFAC model. The UNIFAC group interaction parameters have been found to have a linear temperature dependence. The CH{sub 2} groups in cyclo and non-cyclo paraffins require different interaction parameters. It was also found that a scaling of the combinatorial term is necessary for higher molecular weight hydrocarbons. 13 refs., 12 figs., 5 tabs.

Liquid crystalline biopolymers: A new arena for liquid crystal research

International Nuclear Information System (INIS)

Rizvi, Tasneem Zahra

2001-07-01

This paper gives a brief introduction to liquid crystals on the basis of biopolymers and reviews literature on liquid crystalline behaviour of biopolymers both in vitro and in vivo in relation to their implications in the fields of biology, medicine and material science. Knowledge in the field of biological liquid crystals is crucial for understanding complex phenomena at supramolecular level which will give information about processes involved in biological organization and function. The understanding of the interaction of theses crystals with electric, magnetic, optical and thermal fields will uncover mechanisms of near quantum-energy detection capabilities of biosystems

Fluorescent optical liquid-level sensor

International Nuclear Information System (INIS)

Weiss, Jonathan D.

2000-01-01

An optical method of detecting a liquid level is presented that uses fluorescence radiation generated in an impurity-doped glass or plastic slab. In operation, the slab is inserted into the liquid and pump light is coupled into it so that the light is guided by the slab-air interface above the liquid and escapes into the liquid just below its surface. Since the fluorescence is generated only in that section of the slab above the liquid, the fluorescence power will monotonically decrease with increasing liquid level. Thus, a relationship can be established between any signal proportional to it and the liquid level. Because optical fibers link the pump source and the detector of fluorescence radiation to the sensor, no electrical connections are needed in or near the liquid. Their absence vastly decreases the hazard associated with placing a liquid-level sensor in a potentially explosive environment. A laboratory prototype, consisting of a methyl styrene slab doped with an organic dye, has been built and successfully tested in water. Its response to liquid level when pumped by a tunable argon-ion laser at 476, 488, and 496 nm, and by a blue LED, is presented and shown to be consistent with theory. The fluorescence spectra, optical efficiency, temperature, and other effects are also presented and discussed. (c) 2000 Society of Photo-Optical Instrumentation Engineers

Liquid-liquid structure transition and nucleation in undercooled Co-B eutectic alloys

Energy Technology Data Exchange (ETDEWEB)

He, Yixuan [Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, Xi' an, Shanxi (China); Universite Grenoble Alpes, LNCMI, Grenoble (France); CNRS, LNCMI, Grenoble (France); Li, Jinshan; Wang, Jun; Kou, Hongchao [Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, Xi' an, Shanxi (China); Beagunon, Eric [Universite Grenoble Alpes, LNCMI, Grenoble (France); CNRS, LNCMI, Grenoble (France)

2017-06-15

Cyclic superheating and cooling were carried out for the undercooled hypereutectic Co{sub 80}B{sub 20}, eutectic Co{sub 81.5}B{sub 18.5,} and hypoeutectic Co{sub 83}B{sub 17} alloys. For each alloy, there is a critical overheating temperature T{sub c}° at which there is a sharp increase of the mean undercooling, i.e., below (above) T{sub c}°, and the mean undercooling is about 80 °C (200 °C). DSC measurements show that there is a thermal absorption peak in the heating process, the peak temperature of which is nearly equal to the critical overheating temperature, indicating that the temperature-induced liquid-liquid structure transition does occur and should relate highly to nucleation in the undercooled Co-B eutectic melts. The effect of the liquid-liquid structure transition on nucleation was interpreted by the recent nucleation theory that considers the structures of overheated melts, and the composition-dependent overheating temperature was ascribed to the change of local favored structures. The present work provides further evidences for the liquid-liquid structure transition and is helpful for understanding solidification in undercooled melts. (orig.)

Liquidity Risk and Syndicate Structure

OpenAIRE

Evan Gatev; Philip Strahan

2008-01-01

We offer a new explanation of loan syndicate structure based on banks' comparative advantage in managing systematic liquidity risk. When a syndicated loan to a rated borrower has systematic liquidity risk, the fraction of passive participant lenders that are banks is about 8% higher than for loans without liquidity risk. In contrast, liquidity risk does not explain the share of banks as lead lenders. Using a new measure of ex-ante liquidity risk exposure, we find further evidence that syndica...

STM in liquids. A scanning tunneling microscopy exploration of the liquid-solid interface.

NARCIS (Netherlands)

Hulsken, B.

2008-01-01

This thesis reports of a series of atomic scale studies of the liquid-solid interface, carried out with a home-built liquid-cell Scanning Tunnelling Microscope (STM). The home-built liquid-cell STM is described in detail, and numerical simulations are performed to show that surfaces immersed in the

Quaternary (liquid + liquid) equilibrium data for the extraction of toluene from alkanes using the ionic liquid [EMim][MSO4

International Nuclear Information System (INIS)

Corderí, Sandra; Calvar, Noelia; Gómez, Elena; Domínguez, Ángeles

2014-01-01

Highlights: • EMim[MSO 4 ] was proposed as solvent for the extraction of toluene from alkanes. • The quaternary system {heptane + cyclohexane + toluene + [EMim][MSO 4 ]} was evaluated. • The extraction of toluene would be facilitated in the presence of one alkane. • Experimental LLE data were successfully correlated with the NRTL model. - Abstract: (Liquid + liquid) equilibrium (LLE) studies for the extraction of aromatics from alkanes present in the petroleum fractions are important to develop theoretical/semiempirical (liquid + liquid) equilibrium models, which are used in the design of extraction processes. In this work, the ionic liquid 1-ethyl-3-methylimidazolium methylsulfate, [EMim][MSO 4 ], was evaluated as potential solvent for the separation of toluene from heptane and cyclohexane. The LLE data for the quaternary system {heptane (1) + cyclohexane (2) + toluene (3) + [EMim][MSO 4 ] (4)} were experimentally determined at T = 298.15 K and atmospheric pressure. Moreover, the LLE data for the ternary systems {heptane or cyclohexane (1) + toluene (2) + [EMim][MSO 4 ] (3)} were also determined. Solute distribution ratios and selectivities were calculated and analysed in order to evaluate the capability of the ionic liquid to accomplish the separation target. A comparison between the solute distribution ratios and selectivities for the quaternary and the ternary systems was also made. Finally, the experimental tie-line data were correlated with the NRTL model

Membrane assisted liquid-liquid extraction of cerium

International Nuclear Information System (INIS)

Soldenhoff, K.M.

2000-02-01

Membrane assisted liquid-liquid extraction of cerium was investigated, with emphasis placed on the study of the reaction chemistry and the kinetics of non-dispersive solvent extraction and stripping with microporous membranes. A bulk liquid membrane process was developed for the purification of cerium(IV) from sulfate solutions containing other rare earth elements. The cerium process was studied in both a flat sheet contained liquid membrane configuration and with hollow fibre contactors. Di-2-ethylhexyl phosphoric acid (DEHPA) was identified as a suitable extractant for cerium(IV) from sulfuric acid solution, with due consideration of factors such as extraction ability, resistance to degradation, solvent selectivity and potential for sulfate transfer into a strip solution. A detailed study of the extraction of cerium(IV) with DEHPA defined the extraction reaction chemistry. The Ce/DEHPA/sulfate system was also investigated with a flat sheet bulk liquid membrane configuration, using both sulfuric and hydrochloric acid as receiver solutions. These tests identified that hydrophobic membranes provide better mass transfer for extraction and hydrophilic membranes are better for stripping. The presence of an impurity, mono 2-ethylhexyl phosphoric acid (MEHPA), was found to have a dramatic accelerating effect on the rate of the chemical extraction reaction. This was attributed to its higher interfacial activity and population compared to DEHPA, and the fact that MEHPA was also found to be an active carrier for cerium(IV). The mass transfer rate of membrane assisted extraction and stripping of cerium, using hydrophobic and hydrophilic microporous membranes, respectively, was investigated using a modified Lewis-type cell. It was quantitatively demonstrated that the extraction process was mainly controlled by membrane diffusion and the stripping process was controlled by the chemical reaction rate, with membrane diffusion becoming important at low distribution coefficients

Ionic liquid ultrasound assisted dispersive liquid-liquid microextraction method for preconcentration of trace amounts of rhodium prior to flame atomic absorption spectrometry determination

Energy Technology Data Exchange (ETDEWEB)

Molaakbari, Elaheh [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Young Research Society, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Mostafavi, Ali, E-mail: mostafavi.ali@gmail.com [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Afzali, Daryoush [Environment and Nanochemistry Department, Research Institute of Environmental Science, International Center for Science, High Technology and Environmental Science, Kerman (Iran, Islamic Republic of); Mineral Industries Research Center, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

2011-01-30

In this article, we consider ionic liquid based ultrasound-assisted dispersive liquid-liquid microextraction of trace amounts of rhodium from aqueous samples and show that this is a fast and reliable sample pre-treatment for the determination of rhodium ions by flame atomic absorption spectrometry. The Rh(III) was transferred into its complex with 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol as a chelating agent, and an ultrasonic bath with the ionic liquid, 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide at room temperature was used to extract the analyte. The centrifuged rhodium complex was then enriched in the form of ionic liquid droplets and prior to its analysis by flame atomic absorption spectrometry, 300 {mu}L ethanol was added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh(III) was optimized. Under optimum conditions, the calibration graph was linear in the range of 4.0-500.0 ng mL{sup -1}, the detection limit was 0.37 ng mL{sup -1} (3S{sub b}/m, n = 7) and the relative standard deviation was {+-}1.63% (n = 7, C = 200 ng mL{sup -1}). The results show that ionic liquid based ultrasound assisted dispersive liquid-liquid microextraction, combined with flame atomic absorption spectrometry, is a rapid, simple, sensitive and efficient analytical method for the separation and determination of trace amounts of Rh(III) ions with minimum organic solvent consumption.

Liquidity and liquidity cost vs. bank profitability. A model analysis attempt

OpenAIRE

Boguslaw Guzik

2008-01-01

The author suggests a “model” of relations between liquidity, costs of liquidity and basic or empirical profitability. The first part of the article present the idea of the model analysis. The author makes an effort to explain the frequent empirical paradox – when an increase of liquidity is accompanied by an increase in profitability. The second part present the model analysis in more detail. The author refers to the economic and econometrical model formation. He suggests using the bank prof...

Fundamental study on cavitation erosion in liquid metal. Effect of liquid parameter on cavitation erosion in liquid metals (Joint research)

International Nuclear Information System (INIS)

Hattori, Shuji; Kurachi, Hiroaki; Inoue, Fumitaka; Watashi, Katsumi; Tsukimori, Kazuyuki; Yada, Hiroki; Hashimoto, Takashi

2009-02-01

Cavitation erosion, which possibly occurs on the surfaces of fluid machineries and components contacting flowing liquid and causes sponge-like damage on the material surface, is important problem, since it may become the cause of performance deduction, life shortening, noise, vibration of mechanical components and moreover failure of machine. Research on cavitation erosion in liquid metal is very important to confirm the safety of fast breeder reactor using sodium coolant and to avoid serious damage of the target vessel of spallation neutron source containing liquid-mercury. But the research on cavitation erosion in liquid metal has been hardly performed because of its specially in comparison with that in water. In this study, a cavitation erosion test apparatus was developed to carry out the erosion tests in low-temperature liquid metals. Cavitation erosion tests were carried out in liquid lead-bismuth alloy and in deionized water. We discuss the effect of liquid parameters and temperature effects on the erosion rate. We reach to the following conclusions. The erosion rate was evaluated in terms of a relative temperature which was defind as the percentage between freezing and boiling points. At 14degC relative temperature, the erosion rate is 10 times in lead-bismuth alloy, and 2 to 5 times in sodium, compared with that in deionized water. At 14degC relative temperature, the erosion rate can be evaluated in terms of the following parameter. 1 / (1/ρ L /C L +1/ρ S C S )√ρ L . Where ρ is the material density and c is the velocity of sound, L and S denote liquid and solid. In the relative temperature between 14 and 30degC, the temperature dependence on the erosion rate is due to the increase in vapor pressure. (author)

Metal extraction by solid-liquid agglomerates

International Nuclear Information System (INIS)

Fuller, E.F.

1980-01-01

Dissolved metal values are extracted from a liquid e.g. uranium from phosphoric acid by contacting the liquid with agglomerates for a time to load the agglomerate with the metal value, separating the loaded agglomerates from the liquid phase and stripping the metal value from the loaded agglomerate. The agglomerate may be made by combining finely divided solid particles with a binding liquid to form a paste, adding a suspending liquid to form a mixture, the suspending liquid and binding liquid being immiscible in each other and the solid particles being insoluble in the suspending liquid and shearing the mixture to form the agglomerate. (author)

Taylor Instability of Incompressible Liquids

Science.gov (United States)

Fermi, E.; von Neumann, J.

1955-11-01

A discussion is presented in simplified form of the problem of the growth of an initial ripple on the surface of an incompressible liquid in the presence of an acceleration, g, directed from the outside into the liquid. The model is that of a heavy liquid occupying at t = 0 the half space above the plane z = 0, and a rectangular wave profile is assumed. The theory is found to represent correctly one feature of experimental results, namely the fact that the half wave of the heavy liquid into the vacuum becomes rapidly narrower while the half wave pushing into the heavy liquid becomes more and more blunt. The theory fails to account for the experimental results according to which the front of the wave pushing into the heavy liquid moves with constant velocity. The case of instability at the boundary of 2 fluids of different densities is also explored. Similar results are obtained except that the acceleration of the heavy liquid into the light liquid is reduced.

Decontamination liquid waste processing method

International Nuclear Information System (INIS)

Enda, Masami; Hosaka, Katsumi.

1992-01-01

Liquid wastes after electrolytic reduction are caused to flow through an anionic exchange membrane in a diffusion dialysis step, and liquid wastes and dialyzed water are passed in a countercurrent manner. Since acids in the liquid wastes transfer on the side of the dialyzed water due to the difference of concentration between the liquid wastes and the dialyzed water, acids can be easily recovered from the liquid wastes. If the acid-removed liquid wastes are put to electrodeposition in an electrodepositing step, the electrodepositing reactions between radioactive materials such as Co ion, Mn ion and leached metals such as Fe ions and Cr ions are caused preferentially to hydrogen generation reaction on a metal deposition cathode. Accordingly, metal ions can be easily separated from the liquid wastes. Since the separated liquid wastes are an aqueous solution in which cerium ions as a decontaminant and an acid at low concentration are dissolved, the concentration thereof is controlled by mixing them to acid recovering water after the diffusion dialysis and they can be reused as the decontaminant. (T.M.)

Elimination of liquid discharge to the environment from the TA-50 Radioactive Liquid Waste Treatment Facility

International Nuclear Information System (INIS)

Moss, D.; Williams, N.; Hall, D.; Hargis, K.; Saladen, M.; Sanders, M.; Voit, S.; Worland, P.; Yarbro, S.

1998-06-01

Alternatives were evaluated for management of treated radioactive liquid waste from the radioactive liquid waste treatment facility (RLWTF) at Los Alamos National Laboratory. The alternatives included continued discharge into Mortandad Canyon, diversion to the sanitary wastewater treatment facility and discharge of its effluent to Sandia Canyon or Canada del Buey, and zero liquid discharge. Implementation of a zero liquid discharge system is recommended in addition to two phases of upgrades currently under way. Three additional phases of upgrades to the present radioactive liquid waste system are proposed to accomplish zero liquid discharge. The first phase involves minimization of liquid waste generation, along with improved characterization and monitoring of the remaining liquid waste. The second phase removes dissolved salts from the reverse osmosis concentrate stream to yield a higher effluent quality. In the final phase, the high-quality effluent is reused for industrial purposes within the Laboratory or evaporated. Completion of these three phases will result in zero discharge of treated radioactive liquid wastewater from the RLWTF

Elimination of liquid discharge to the environment from the TA-50 Radioactive Liquid Waste Treatment Facility

Energy Technology Data Exchange (ETDEWEB)

Moss, D.; Williams, N.; Hall, D.; Hargis, K.; Saladen, M.; Sanders, M.; Voit, S.; Worland, P.; Yarbro, S.

1998-06-01

Alternatives were evaluated for management of treated radioactive liquid waste from the radioactive liquid waste treatment facility (RLWTF) at Los Alamos National Laboratory. The alternatives included continued discharge into Mortandad Canyon, diversion to the sanitary wastewater treatment facility and discharge of its effluent to Sandia Canyon or Canada del Buey, and zero liquid discharge. Implementation of a zero liquid discharge system is recommended in addition to two phases of upgrades currently under way. Three additional phases of upgrades to the present radioactive liquid waste system are proposed to accomplish zero liquid discharge. The first phase involves minimization of liquid waste generation, along with improved characterization and monitoring of the remaining liquid waste. The second phase removes dissolved salts from the reverse osmosis concentrate stream to yield a higher effluent quality. In the final phase, the high-quality effluent is reused for industrial purposes within the Laboratory or evaporated. Completion of these three phases will result in zero discharge of treated radioactive liquid wastewater from the RLWTF.

Efficacy of Intravitreal Bevacizumab in Treatment of Proliferative Type 2 Idiopathic Juxtafoveal Telangiectasia

Directory of Open Access Journals (Sweden)

Ökkeş Baz

2017-06-01

Full Text Available Objectives: To evaluate the effectiveness of intravitreal bevacizumab (IVB in patients with subretinal neovascularization secondary to type 2 juxtafoveal telangiectasia. Materials and Methods: Ten eyes of 10 patients were included in this retrospective study. All cases were treated with IVB (1.25 mg bevacizumab. Visual acuity and slit-lamp anterior and posterior segment examinations were performed at each visit. Central macular thickness (CMT and intraretinal/subretinal fluid were evaluated via spectral domain optical coherence tomography (OCT. Loss of a line in visual acuity chart and presence of fluid on OCT were defined as criteria for repeated treatment. Results: The mean age of patients was 66.0±7.0 years (56-75. The mean follow-up time was 54.7±16.0 month (24-72. The mean BCVA was 0.62±0.35 (0.00-1.00 logMAR at baseline and 0.54±0.35 (0.00-1.00 logMAR at final exam (p=0.03. The mean CMT was 251±25.4 µm at baseline and 239±39.3 µm at final exam (p=0.01. Patients received an average of 1.7±1.0 IVB injections during follow-up. At baseline, all cases had intraretinal/subretinal fluid. There was no fluid at final examination of all cases. Conclusion: IVB treatment may be effective in the treatment of subretinal neovascularization secondary to type 2 juxtafoveal telangiectasia.

Bilateral patching in retinal detachment: fluid mechanics and retinal "settling".

Science.gov (United States)

Foster, William J

2011-07-20

When a patient suffers a retinal detachment and surgery is delayed, it is known clinically that bilaterally patching the patient may allow the retina to partially reattach or "settle." Although this procedure has been performed since the 1860s, there is still debate as to how such a maneuver facilitates the reattachment of the retina. Finite element calculations using commercially available analysis software are used to elucidate the influence of reduction in eye movement caused by bilateral patching on the flow of subretinal fluid in a physical model of retinal detachment. It was found that by coupling fluid mechanics with structural mechanics, a physically consistent explanation of increased retinal detachment with eye movements can be found in the case of traction on the retinal hole. Large eye movements increase vitreous traction and detachment forces on the edge of the retinal hole, creating a subretinal vacuum and facilitating increased subretinal fluid. Alternative models, in which intraocular fluid flow is redirected into the subretinal space, are not consistent with these simulations. The results of these simulations explain the physical principles behind bilateral patching and provide insight that can be used clinically. In particular, as is known clinically, bilateral patching may facilitate a decrease in the height of a retinal detachment. The results described here provide a description of a physical mechanism underlying this technique. The findings of this study may aid in deciding whether to bilaterally patch patients and in counseling patients on pre- and postoperative care.

Repair mechanism of retinal pigment epithelial tears in age-related macular degeneration.

Science.gov (United States)

Mukai, Ryo; Sato, Taku; Kishi, Shoji

2015-03-01

To investigate repair mechanisms of retinal pigment epithelial (RPE) tears in age-related macular degeneration. The authors retrospectively studied 10 eyes with age-related macular degeneration that developed RPE tears during follow-up or after treatment with an anti-vascular endothelial growth factor drug or photodynamic therapy combined with ranibizumab. After development of the RPE tears, all follow-ups exceeded 13 months. Spectral domain or swept-source optical coherence tomography have been used to examine consecutive retinal changes where the RPE tears developed and attempted to determine the repair mechanisms. Retinal pigment epithelial tears developed during the natural course (n = 4) after ranibizumab treatment (n = 2) and after photodynamic therapy and ranibizumab (n = 4). Subretinal fluid persisted for more than 6 months after the RPE tears developed (n = 4), with the area where the RPE was lost found to be covered with thickened proliferative tissue. In 6 eyes where the subretinal fluid was absorbed within 2 months, optical coherence tomography showed the outer retina appeared to be directly attached to Bruch membrane, and there was attenuation of the normal hyperreflective band attributable to normal RPE during follow-up. Results suggest that two repair processes may be present in the area where RPE tears developed. Persistent subretinal fluid may lead to repair with thick proliferative tissue, while the outer retina appears to attach to Bruch membrane when there is early subretinal fluid resolution after RPE tear development.

(Liquid + liquid) equilibria for the ternary mixtures (alkane + toluene + ionic liquid) at T = 298.15 K: Influence of the anion on the phase equilibria

International Nuclear Information System (INIS)

Seoane, Raquel G.; Gómez, Elena; González, Emilio J.; Domínguez, Ángeles

2012-01-01

Highlights: ► [BMpyr][NTF 2 ] and [BMpyr][TFO] were studied as solvents to extract aromatics from alkanes. ► (Liquid + liquid) equilibrium data were measured at 298.15 K for six ternary systems. ► Selectivity and solute distribution ratio were calculated and compared. ► The influence of the structure of anion of the ionic liquid was analyzed. ► Experimental data were satisfactorily correlated using NRTL model. - Abstract: (Liquid + liquid) equilibrium data for the ionic liquids 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [BMpyr][NTf 2 ], and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, [BMpyr][TFO], with toluene, and heptane or cyclohexane were determined at T = 298.15 K and atmospheric pressure. In order to check if these ILs can be used as potential solvents for the extraction of toluene from aliphatic compounds, the ability of the ILs as solvents was evaluated in terms of selectivity and solute distribution ratio. The experimental data were correlated accurately with the Non Random Two-Liquid model.

Transient shielded liquid hydrogen containers

International Nuclear Information System (INIS)

Varghese, A.P.; Herring, R.H.

1990-01-01

The storage of hydrogen in the liquid phase has been limited in duration due to the thermal performance constraints of conventional Liquid Hydrogen containers available. Conventional Liquid Hydrogen containers lose hydrogen because of their relatively high heat leak and variations in usage pattern of hydrogen due to shutdowns. Local regulations also discourage venting of hydrogen. Long term storage of Liquid Hydrogen without product loss was usually accomplished using Liquid Nitrogen sacrificial shields. This paper reports on a new low heat leak container developed and patented that will extend the storage time of liquid hydrogen by five hundred percent. The principle of operation of the Transient Shields which makes the extraordinary performance of this container feasible is described in this paper. Also covered are the impact of this new container on present applications of hydrogen and the new opportunities afforded to Liquid hydrogen in the world hydrogen market

Characterization of a bonding-in-liquid technique for liquid encapsulation into MEMS devices

International Nuclear Information System (INIS)

Okayama, Yoshiyuki; Nakahara, Keijiro; Arouette, Xavier; Ninomiya, Takeshi; Matsumoto, Yasuaki; Orimo, Yoshinori; Hotta, Atsushi; Omiya, Masaki; Miki, Norihisa

2010-01-01

We demonstrate and characterize a new bonding-in-liquid technique (BiLT) for the encapsulation of liquids in MEMS devices. Liquid encapsulation enables innovative MEMS devices with various functions exploiting the unique characteristics of liquids, such as high deformation and spherical shape due to surface tension. Interfusion of air bubbles, variation of the liquid quantity and leakage of the encapsulated liquid must be avoided, or device performance will deteriorate. In BiLT, two structural layers are passively aligned and brought into contact in a solution, and the encapsulation cavities are filled uniformly with liquid, without air bubbles. A UV-curable resin is used as an adhesive that does not require heat or vacuum to bond the layers, but UV irradiation. DI water, glycerin and phosphate buffer saline were successfully encapsulated in silicon structural layers with PDMS membranes. We experimentally evaluated the bond strengths and alignment accuracy of BiLT in order to provide crucial information for the application of this process to the packaging and/or manufacturing of MEMS devices. Since conventional aligners are not applicable to BiLT, we experimentally evaluated the accuracy of an in-solution passive alignment process, which made use of matching concave and convex structures.

Interactions in ion pairs of protic ionic liquids: Comparison with aprotic ionic liquids

International Nuclear Information System (INIS)

Tsuzuki, Seiji; Shinoda, Wataru; Miran, Md. Shah; Kinoshita, Hiroshi; Yasuda, Tomohiro; Watanabe, Masayoshi

2013-01-01

The stabilization energies for the formation (E form ) of 11 ion pairs of protic and aprotic ionic liquids were studied by MP2/6-311G ** level ab initio calculations to elucidate the difference between the interactions of ions in protic ionic liquids and those in aprotic ionic liquids. The interactions in the ion pairs of protic ionic liquids (diethylmethylammonium [dema] and dimethylpropylammonium [dmpa] based ionic liquids) are stronger than those of aprotic ionic liquids (ethyltrimethylammonium [etma] based ionic liquids). The E form for the [dema][CF 3 SO 3 ] and [dmpa][CF 3 SO 3 ] complexes (−95.6 and −96.4 kcal/mol, respectively) are significantly larger (more negative) than that for the [etma][CF 3 SO 3 ] complex (−81.0 kcal/mol). The same trend was observed for the calculations of ion pairs of the three cations with the Cl − , BF 4 − , TFSA − anions. The anion has contact with the N–H bond of the dema + or dmpa + cations in the most stable geometries of the dema + and dmpa + complexes. The optimized geometries, in which the anions locate on the counter side of the cations, are 11.0–18.0 kcal/mol less stable, which shows that the interactions in the ions pairs of protic ionic liquids have strong directionality. The E form for the less stable geometries for the dema + and dmpa + complexes are close to those for the most stable etma + complexes. The electrostatic interaction, which is the major source of the attraction in the ion pairs, is responsible for the directionality of the interactions and determining the magnitude of the interaction energy. Molecular dynamic simulations of the [dema][TFSA] and [dmpa][TFSA] ionic liquids show that the N–H bonds of the cations have contact with the negatively charged (oxygen and nitrogen) atoms of TFSA − anion, while the strong directionality of the interactions was not suggested from the simulation of the [etma][CF 3 SO 3 ] ionic liquid

Uranium Extraction From Artificial Liquid Waste Using Continuous Extraction Liquid membrane Technique

International Nuclear Information System (INIS)

Rusdianasari; Buchari

2002-01-01

The continuous extraction of uranium from artificial liquid waste by emulsion liquid membrane was carried out using one stage mixer-settler. This emulsion liquid membrane containing di-2-ethylhexylphosphoric acid (D2EHPA) and tri-n-buthyl phosphate (TBP) as carrier were carried out using one stage mixer-settler. The optimum condition gave the ratio of emulsion velocity to the feed velocity 1:4 and steady state reached after five minutes. The optimum condition was obtained at the 90.91 % of uranium recovered from raffinate, using EDTA as the masking agent with concentration 5x10 - 2 M . The total concentration of carrier was 3% with ratio D2EHPA and TBP 3:1. The emulsion liquid membrane has high relative selectivity after steady state with separation factors were α U , N i= 115,43 and α U , Fe 328,55. The result of experiment showed that emulsion liquid membrane containing D2EHPA and TBP as carrier have good performance for continuous system

Liquid holdup in turbulent contact absorber

International Nuclear Information System (INIS)

Haq, A.; Zaman, M.; Inayat, M.H.; Chughtai, I.R.

2009-01-01

Dynamic liquid holdup in a turbulent contact absorber was obtained through quick shut off valves technique. Experiments were carried out in a Perspex column. Effects of liquid velocity, gas velocity, packing diameter packing density and packing height on dynamic liquid holdup were studied. Hollow spherical high density polyethylene (HDPE) balls were used as inert fluidized packing. Experiments were performed at practical range of liquid and gas velocities. Holdup was calculated on the basis of static bed height. Liquid holdup increases with increasing both liquid and gas velocities both for type 1 and type 2 modes of fluidization. Liquid holdup increases with packing density. No effect of dia was observed on liquid holdup. (author)

Liquidity management through financial planning

Directory of Open Access Journals (Sweden)

Kameníková Katarína

2001-12-01

Full Text Available One of the basic goals of financial management is to provide financial property and capital for running of the firm, as well as for its development, that means provide optimal firm´s liquidity.To improve liquidity is possible provide through various ways. In present time there is increasing importance of financial planning., where planning of liquidity presents one of its integral part. Therefore I deal in presented paper with possible liquidity improvement through calculation of financial planning in chosen slovac magnesite firm, exploitating and elaborating magnesite raw material.For creating of financial plann of liquidity I chosed to use one of the practical methods - method of financial indexes. Such method presents process of planning optimal liquidity with providing of required rentability. Such plann must provide balance between income and outcome, as well as secure achievment of expected profit.I used tools of financial planning for calculation of possible liquidity improvement in mentioned firm, where present financial situation is characterised by law liquidity, but high rentability. Such position presents transitive crisis situation, therefore firm must create new financial property or decrease liabilities, in order to overcome negative state of liquidity.Performed calculation showed, that change in balance sheet due to the growth of financial property will improve liquidity, rentability will be maintained, therefore firm will be able to transit from crisis situation.Providing of liquidity will present one of possible way how to care for financial health of firm. But such process is not simple, it must be done with connection to the changes of internal and external conditions of the firm.

The theory of quantum liquids

CERN Document Server

Nozières, Philippe

1999-01-01

Originally published as two separate volumes, The Theory of Quantum Liquids is a classic text that attempts to describe the qualitative and unifying aspects of an extremely broad and diversified field. Volume I deals with 'normal' Fremi liquids, such as 3He and electrons in metals. Volume II consists of a detailed treatment of Bose condensation and liquid 4He, including the development of a Bose liquid theory and a microscopic basis for the two-fluid model, and the description of the elementary excitations of liquid HeII.

Safe and Liquid Mortgage Bonds

DEFF Research Database (Denmark)

Dick-Nielsen, Jens; Gyntelberg, Jacob; Lund, Jesper

This paper shows that strict match pass-through funding of covered bonds provides safe and liquid mortgage bonds. Despite a 30% drop in house prices during the 2008 global crisis Danish mortgage bonds remained as liquid as most European government bonds. The Danish pass-through system effectively...... eliminates credit risk from the investor's perspective. Similar to other safe bonds, funding liquidity becomes the main driver of mortgage bond liquidity and this creates commonality in liquidity across markets and countries. These findings have implications for how to design a robust mortgage bond system...

Column Liquid Chromatography.

Science.gov (United States)

Majors, Ronald E.; And Others

1984-01-01

Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

Microorganism mediated liquid fuels

Energy Technology Data Exchange (ETDEWEB)

Troiano, Richard

2018-03-20

Herein disclosed is a method for producing liquid hydrocarbon product, the method comprising disintegrating a hydrocarbon source; pretreating the disintegrated hydrocarbon source; solubilizing the disintegrated hydrocarbon source to form a slurry comprising a reactant molecule of the hydrocarbon source; admixing a biochemical liquor into the slurry, wherein the biochemical liquor comprises at least one conversion enzyme configured to facilitate bond selective photo-fragmentation of said reactant molecule of the hydrocarbon source, to form liquid hydrocarbons via enzyme assisted bond selective photo-fragmentation, wherein said conversion enzyme comprises reactive sites configured to restrict said reactant molecule such that photo-fragmentation favorably targets a preselected internal bond of said reactant molecule; separating the liquid hydrocarbons from the slurry, wherein contaminants remain in the slurry; and enriching the liquid hydrocarbons to form a liquid hydrocarbon product. Various aspects of such method/process are also discussed.

Lewis Acidic Ionic Liquids.

Science.gov (United States)

Brown, Lucy C; Hogg, James M; Swadźba-Kwaśny, Małgorzata

2017-08-21

Until very recently, the term Lewis acidic ionic liquids (ILs) was nearly synonymous with halometallate ILs, with a strong focus on chloroaluminate(III) systems. The first part of this review covers the historical context in which these were developed, speciation of a range of halometallate ionic liquids, attempts to quantify their Lewis acidity, and selected recent applications: in industrial alkylation processes, in supported systems (SILPs/SCILLs) and in inorganic synthesis. In the last decade, interesting alternatives to halometallate ILs have emerged, which can be divided into two sub-sections: (1) liquid coordination complexes (LCCs), still based on halometallate species, but less expensive and more diverse than halometallate ionic liquids, and (2) ILs with main-group Lewis acidic cations. The two following sections cover these new liquid Lewis acids, also highlighting speciation studies, Lewis acidity measurements, and applications.

Separating particles from a liquid

International Nuclear Information System (INIS)

Leslie, C.M.; Watson, J.H.P.; Williams, J.A.

1980-01-01

An apparatus for separating particles suspended in a liquid from the liquid, is described, in which a flow of the liquid is passed through a filter bed of ferromagnetic bodies which acts as a coarse filter to trap the larger particles in the flow. The filter bed is arranged within a truncated core between the poles of an electromagnet. To cleanse the bed and flush out the trapped particles a wash liquid is passed through the bed and the electromagnet is energised to levitate the bed to allow the wash liquid to remove the particles. The liquid flow from the coarse filter can be passed to a high gradient magnetic separator at which remaining small particles in the flow are filtered magnetically. (U.K.)

Simultaneous determination of several phytohormones in natural coconut juice by hollow fiber-based liquid-liquid-liquid microextraction-high performance liquid chromatography.

Science.gov (United States)

Wu, Yunli; Hu, Bin

2009-11-06

A simple, selective, sensitive and inexpensive method of hollow fiber-based liquid-liquid-liquid microextraction (HF-LLLME) combined with high performance liquid chromatography (HPLC)-ultraviolet (UV) detection was developed for the determination of four acidic phytohormones (salicylic acid (SA), indole-3-acetic acid (IAA), (+/-) abscisic acid (ABA) and (+/-) jasmonic acid (JA)) in natural coconut juice. To the best of our knowledge, this is the first report on the use of liquid phase microextraction (LPME) as a sample pretreatment technique for the simultaneous analysis of several phytohormones. Using phenetole to fill the pores of hollow fiber as the organic phase, 0.1molL(-1) NaOH solution in the lumen of hollow fiber as the acceptor phase and 1molL(-1) HCl as the donor phase, a simultaneous preconcentration of four target phytohormones was realized. The acceptor phase was finally withdrawn into the microsyringe and directly injected into HPLC for the separation and quantification of the target phytohormones. The factors affecting the extraction efficiency of four phytohormones by HF-LLLME were optimized with orthogonal design experiment, and the data was analyzed by Statistical Product and Service Solutions (SPSS) software. Under the optimized conditions, the enrichment factors for SA, IAA, ABA and JA were 243, 215, 52 and 48, with the detection limits (S/N=3) of 4.6, 1.3, 0.9ngmL(-1) and 8.8 microg mL(-1), respectively. The relative standard deviations (RSDs, n=7) were 7.9, 4.9, 6.8% at 50ngmL(-1) level for SA, IAA, ABA and 8.4% at 500 microg mL(-1) for JA, respectively. To evaluate the accuracy of the method, the developed method was applied for the simultaneous analysis of several phytohormones in five natural coconut juice samples, and the recoveries for the spiked samples were in the range of 88.3-119.1%.

[Dynamics of pleural liquid in hydrothorax].

Science.gov (United States)

Nakamura, T; Iwaskai, Y; Gotoh, T; Hiramori, N; Fujii, T; Sakai, M; Nakagaki, Y; Arimoto, T; Mizobuchi, K; Hashikura, H

1994-12-01

The basics of pleural liquid dynamics are summarized. The normal pleural cavity contains a small amount of pleural liquid (0.1-0.3 ml/kg). Its protein concentration is about 1.0 g/dl and its pH is 7.6. The normal flow of pleural liquid is gravity dependent, and pleural liquid flows from the costal to the mediastinal region. In experimental hydrothorax, the pleural liquid was removed mainly via lymphatics. The turnover of the pleural liquid is rapid, and it depends on the area of contact between pleural liquid and pleural and on the blood flow to the pleura.

[High-performance liquid-liquid chromatography in beverage analysis].

Science.gov (United States)

Bricout, J; Koziet, Y; de Carpentrie, B

1978-01-01

Liquid liquid chromatography was performed with columns packed with stationary phases chemically bonded to silica microparticules. These columns show a high efficiency and are used very easily. Flavouring compounds like aromatic aldehydes which have a low volatility were analyzed in brandy using a polar phase alkylnitrile. Sapid substances like amarogentin in Gentiana lutea or glyryrrhizin in Glycyrrhiza glabra were determined by reversed phase chromatography. Finally ionizable substances like synthetic dyes can be analyzed by paired ion chromatography witha non polar stationary phase.

Convenient liquidity measure for Financial markets

OpenAIRE

Danyliv, Oleh; Bland, Bruce; Nicholass, Daniel

2014-01-01

A liquidity measure based on consideration and price range is proposed. Initially defined for daily data, Liquidity Index (LIX) can also be estimated via intraday data by using a time scaling mechanism. The link between LIX and the liquidity measure based on weighted average bid-ask spread is established. Using this liquidity measure, an elementary liquidity algebra is possible: from the estimation of the execution cost, the liquidity of a basket of instruments is obtained. A formula for the ...

Plasma Reforming of Liquid Hydrocarbon Fuels in Non-Thermal Plasma-Liquid Systems

Science.gov (United States)

2010-04-30

channel with liquid wall in the microporous media under the ultrasound cavitations has shown the following: · The action of the ultrasound field in the...microporous liquid which has a very large ratio of the plasma-liquid contact surface to the plasma volume. As is known the ultrasonic (US) cavitation is a very...2) and it ran over a flat dielectric surface of the magnetostrictive transmitter (5) which produced ultrasonic (US) cavitations , so the discharge

Architecture, Assembly, and Emerging Applications of Branched Functional Polyelectrolytes and Poly(ionic liquid)s.

Science.gov (United States)

Xu, Weinan; Ledin, Petr A; Shevchenko, Valery V; Tsukruk, Vladimir V

2015-06-17

Branched polyelectrolytes with cylindrical brush, dendritic, hyperbranched, grafted, and star architectures bearing ionizable functional groups possess complex and unique assembly behavior in solution at surfaces and interfaces as compared to their linear counterparts. This review summarizes the recent developments in the introduction of various architectures and understanding of the assembly behavior of branched polyelectrolytes with a focus on functional polyelectrolytes and poly(ionic liquid)s with responsive properties. The branched polyelectrolytes and poly(ionic liquid)s interact electrostatically with small molecules, linear polyelectrolytes, or other branched polyelectrolytes to form assemblies of hybrid nanoparticles, multilayer thin films, responsive microcapsules, and ion-conductive membranes. The branched structures lead to unconventional assemblies and complex hierarchical structures with responsive properties as summarized in this review. Finally, we discuss prospectives for emerging applications of branched polyelectrolytes and poly(ionic liquid)s for energy harvesting and storage, controlled delivery, chemical microreactors, adaptive surfaces, and ion-exchange membranes.

Vibrational Spectroscopy of Ionic Liquids.

Science.gov (United States)

Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

2017-05-24

Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

Hydrotreating of coal-derived liquids

Energy Technology Data Exchange (ETDEWEB)

Lott, S.E.; Stohl, F.V.; Diegert, K.V. [Sandia National Lab., Albuquerque, NM (United States)] [and others

1995-12-31

To develop a database relating hydrotreating parameters to feed and product quality by experimentally evaluating options for hydrotreating whole coal liquids, distillate cuts of coal liquids, petroleum, and blends of coal liquids with petroleum.

Gas-liquid interface of room-temperature ionic liquids.

Science.gov (United States)

Santos, Cherry S; Baldelli, Steven

2010-06-01

The organization of ions at the interface of ionic liquids and the vacuum is an ideal system to test new ideas and concepts on the interfacial chemistry of electrolyte systems in the limit of no solvent medium. Whilst electrolyte systems have numerous theoretical and experimental methods used to investigate their properties, the ionic liquids are relatively new and our understanding of the interfacial properties is just beginning to be explored. In this critical review, the gas-liquid interface is reviewed, as this interface does not depend on the preparation of another medium and thus produces a natural interface. The interface has been investigated by sum frequency generation vibrational spectroscopy and ultra-high vacuum techniques. The results provide a detailed molecular-level view of the surface composition and structure. These have been complemented by theoretical studies. The combinations of treatments on this interface are starting to provide a somewhat convergent description of how the ions are organized at this neat interface (108 references).

Electrical insulating liquid: A review

Directory of Open Access Journals (Sweden)

Deba Kumar Mahanta

2017-08-01

Full Text Available Insulating liquid plays an important role for the life span of the transformer. Petroleum-based mineral oil has become dominant insulating liquid of transformer for more than a century for its excellent dielectric and cooling properties. However, the usage of petroleum-based mineral oil, derived from a nonrenewable energy source, has affected the environment for its nonbiodegradability property. Therefore, researchers direct their attention to renewable and biodegradable alternatives. Palm fatty acid ester, coconut oil, sunflower oil, etc. are considered as alternatives to replace mineral oil as transformer insulation liquid. This paper gives an extensive review of different liquid insulating materials used in a transformer. Characterization of different liquids as an insulating material has been discussed. An attempt has been made to classify different insulating liquids-based on different properties.

Liquidity Risk and Distressed Equity

DEFF Research Database (Denmark)

Medhat, Mamdouh

I show theoretically and empirically that cash holdings can help rationalize the low returns to distressed equity. In my model, levered firms with financing constraints optimally choose their cash holdings to eliminate liquidity risk and optimally default when insolvent. Using data on solvency......, liquidity, and returns for US firms, I find evidence consistent with the model’s predictions: (1) In all solvency levels, the average firm holds enough liquid assets to cover its short-term liabilities; less solvent firms have (2) a higher fraction of their total assets in liquid assets and therefore (3......) lower conditional betas and (4) lower returns; (5) the profits of long-short solvency strategies are highest among firms with low liquidity; and (6) the profits of long-short liquidity strategies are highest among firms with low solvency....

Ionic-liquid-based dispersive liquid-liquid microextraction combined with magnetic solid-phase extraction for the determination of aflatoxins B1 , B2 , G1 , and G2 in animal feeds by high-performance liquid chromatography with fluorescence detection.

Science.gov (United States)

Zhao, Jiao; Zhu, Yan; Jiao, Yang; Ning, Jinyan; Yang, Yaling

2016-10-01

A novel two-step extraction technique combining ionic-liquid-based dispersive liquid-liquid microextraction with magnetic solid-phase extraction was developed for the preconcentration and separation of aflatoxins in animal feedstuffs before high-performance liquid chromatography coupled with fluorescence detection. In this work, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate was used as the extractant in dispersive liquid-liquid microextraction, and hydrophobic pelargonic acid modified Fe 3 O 4 magnetic nanoparticles as an efficient adsorbent were applied to retrieve the aflatoxins-containing ionic liquid. Notably, the target of magnetic nanoparticles was the ionic liquid rather than the aflatoxins. Because of the rapid mass transfer associated with the dispersive liquid-liquid microextraction and magnetic solid phase steps, fast extraction could be achieved. The main parameters affecting the extraction recoveries of aflatoxins were investigated and optimized. Under the optimum conditions, vortexing at 2500 rpm for 1 min in the dispersive liquid-liquid microextraction and magnetic solid-phase extraction and then desorption by sonication for 2 min with acetonitrile as eluent. The recoveries were 90.3-103.7% with relative standard deviations of 3.2-6.4%. Good linearity was observed with correlation coefficients ranged from 0.9986 to 0.9995. The detection limits were 0.632, 0.087, 0.422 and 0.146 ng/mL for aflatoxins B 1 , B2, G1, and G2, respectively. The results were also compared with the pretreatment method carried out by conventional immunoaffinity columns. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PEP liquid level system

International Nuclear Information System (INIS)

Lauritzen, T.; Sah, R.C.

1981-03-01

A liquid level system has been installed in the accelerator housing of the PEP storage ring. This instrument spans the entire 2.2 km circumference of the PEP project, and over one hundred readouts provide reference elevations which are used for the accurate alignment of accelerator components. The liquid level has proven to be extremely precise (+-0.10 mm) and quick to use, and it has contributed to the accurate alignment of PEP before beam turn-on. Since the liquid level readouts are rigidly attached to the accelerator housing, the liquid level has been a convenient means to monitor the settling of the accelerator housing

Progress in Separation of Gases by Permeation and Liquids by Pervaporation Using Ionic Liquids: A Review

OpenAIRE

Kárászová, M. (Magda); Kačírková, M. (Marie); Friess, K.; Izák, P. (Pavel)

2014-01-01

The effective separation of gases and liquids by membranes containing ionic liquids actually belongs to one of the challenging topics in membrane community. During last decade, a plenty of new kinds of ionic liquids (IL), their combinations, different types of polymerized ionic liquids and polymer–IL composite membranes were developed and tested. This review summarizes the most important achievements and findings connected with the ionic liquid based membranes research and tries to answer h...

About the Shape of the Melting Line as a Possible Precursor of a Liquid-Liquid Phase Transition

Science.gov (United States)

Imre, Attila R.; Rzoska, Sylwester J.

Several simple, non-mesogenic liquids can exists in two or more different liquid forms. When the liquid-liquid line, separating two liquid forms, meets the melting line, one can expect some kind of break on the melting line, caused by the different freezing/melting behaviour of the two liquid forms. Unfortunately recently several researchers are using this vein of thinking in reverse; seeing some irregularity on the melting line, they will expect a break and the appearance of a liquid-liquid line. In this short paper, we are going to show, that in the case of the high-pressure nitrogen studied recently by Mukherjee and Boehler, the high-pressure data can be easily described by a smooth, break-free function, the modified Simon-Glatzel equation. In this way, the break, suggested by them and consequently the suggested appearance of a new liquid phase of the nitrogen might be artefacts.

Comment on "Spontaneous liquid-liquid phase separation of water".

Science.gov (United States)

Limmer, David T; Chandler, David

2015-01-01

Yagasaki et al. [Phys. Rev. E 89, 020301 (2014)] present results from a molecular dynamics trajectory illustrating coarsening of ice, which they interpret as evidence of transient coexistence between two distinct supercooled phases of liquid water. We point out that neither two distinct liquids nor criticality are demonstrated in this simulation study. Instead, the illustrated trajectory is consistent with coarsening behaviors analyzed and predicted in earlier work by others.

Recycling of Metal Containing Waste by Liquid-Liquid Extraction

International Nuclear Information System (INIS)

Reinhardt, H.

1999-01-01

Through the years, a large number of liquid-liquid extraction have been proposed for metal waste recovery and recycling(1,2). However, few of them have achieved commercial application. In fact, relatively little information is available on practical operation and economic feasibility. This presentation will give complementary information by describing and comparing three processes, based on the Am MAR hydrometallurgical concept and representing three different modes of operation

Density of liquid Ytterbium

International Nuclear Information System (INIS)

Stankus, S.V.; Basin, A.S.

1983-01-01

Results are presented for measurements of the density of metallic ytterbium in the liquid state and at the liquid-solid phase transition. Based on the numerical data obtained, the coefficient of thermal expansion βZ of the liquid and the density discontinuity on melting deltarho/sub m/ are calculated. The magnitudes of βZ and deltarho/sub m/ for the heavy lanthanides are compared

Graphene-ionic liquid composites

Energy Technology Data Exchange (ETDEWEB)

Aksay, Ilhan A.; Korkut, Sibel; Pope, Michael; Punckt, Christian

2016-11-01

Method of making a graphene-ionic liquid composite. The composite can be used to make elec-trodes for energy storage devices, such as batteries and supercapacitors. Dis-closed and claimed herein is method of making a graphene-ionic liquid com-posite, comprising combining a graphene source with at least one ionic liquid and heating the combination at a temperature of at least about 130 .degree. C.

Liquidity policies and systemic risk

OpenAIRE

Adrian, Tobias; Boyarchenko, Nina

2013-01-01

The growth of wholesale-funded credit intermediation has motivated liquidity regulations. We analyze a dynamic stochastic general equilibrium model in which liquidity and capital regulations interact with the supply of risk-free assets. In the model, the endogenously time-varying tightness of liquidity and capital constraints generates intermediaries’ leverage cycle, influencing the pricing of risk and the level of risk in the economy. Our analysis focuses on liquidity policies’ implications ...

Physical property, phase equilibrium, distillation. Measurement and prediction of vapor-liquid and liquid-liquid equilibria; Bussei / heiko / joryu. Kieki, ekieki heiko no sokutei to suisan

Energy Technology Data Exchange (ETDEWEB)

Tochigi, K. [Nihon Univ., Tokyo (Japan)

1998-08-05

The data on vapor-liquid equilibrium are basic data indispensable to the designing of a distillation process. The stage required for separation depends greatly upon the x-y curve, and the existence/nonexistence of an azeotropic point is also an important item to be checked. This paper describes the measurement of vapor-liquid equilibrium and liquid-liquid equilibrium, and then introduces reliable data on vapor-liquid equilibrium and parameters of an activity coefficient formula. For the prediction of vapor-liquid equilibrium, the ASOG, UNIFAC, and modified NIFAC, all being group contributive methods are utilized. The differences between these group contributive methods are based on the differences between the contributive items based on the differences in size of molecules influencing the activity coefficients and the expression of the group activity coefficient formula. The applicable number of groups of the ASOG is 43, while that of groups of the UNIFAC is 50. The modified UNIFAC covers 43 groups. The prediction of liquid-liquid equilibrium by using a group contributive method has little progressed since the of the results of the study of Magnussen et al. using the UNIFAC. 12 refs., 8 figs., 1 tab.

Mechanism of magnetic liquid flowing in the magnetic liquid seal gap of reciprocating shaft

Science.gov (United States)

Li, Decai; Xu, Haiping; He, Xinzhi; Lan, Huiqing

2005-03-01

In order to solve the problems that exist in the magnetic liquid seal of reciprocating shaft, we have set up an experimental facility, which composes a camera, microscope, step-by-step motor, pin roller screw, reciprocating motion shaft, pole pieces, permanent magnet and the magnetic liquid in the seal gap. Through the optical technology and image process of the experimental facility, we have studied the magnetic liquid flow in the seal gap when the reciprocating shaft moves with different velocities and strokes. This study specially concentrates on: (1) the regular pattern of such flow; (2) the loss quantity of magnetic liquid caused by the reciprocating motion shaft; (3) the failure reasons of this magnetic liquid seal; and (4) the design of a new structure for the magnetic liquid seal of reciprocating shaft. The application indicates that the new structure is very effective in some occasions. The new structure was accepted as the state patent in 2001 and authenticated as the achievement in the scientific research in 2002.

Mechanism of magnetic liquid flowing in the magnetic liquid seal gap of reciprocating shaft

International Nuclear Information System (INIS)

Li Decai; Xu Haiping; He Xinzhi; Lan Huiqing

2005-01-01

In order to solve the problems that exist in the magnetic liquid seal of reciprocating shaft, we have set up an experimental facility, which composes a camera, microscope, step-by-step motor, pin roller screw, reciprocating motion shaft, pole pieces, permanent magnet and the magnetic liquid in the seal gap. Through the optical technology and image process of the experimental facility, we have studied the magnetic liquid flow in the seal gap when the reciprocating shaft moves with different velocities and strokes. This study specially concentrates on: (1) the regular pattern of such flow; (2) the loss quantity of magnetic liquid caused by the reciprocating motion shaft; (3) the failure reasons of this magnetic liquid seal; and (4) the design of a new structure for the magnetic liquid seal of reciprocating shaft. The application indicates that the new structure is very effective in some occasions. The new structure was accepted as the state patent in 2001 and authenticated as the achievement in the scientific research in 2002

Ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction and derivatization of sulfonamides in river water, honey, milk, and animal plasma.

Science.gov (United States)

Xu, Xu; Su, Rui; Zhao, Xin; Liu, Zhuang; Zhang, Yupu; Li, Dan; Li, Xueyuan; Zhang, Hanqi; Wang, Ziming

2011-11-30

The ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction (IL-based MADLLME) and derivatization was applied for the pretreatment of six sulfonamides (SAs) prior to the determination by high-performance liquid chromatography (HPLC). By adding methanol (disperser), fluorescamine solution (derivatization reagent) and ionic liquid (extraction solvent) into sample, extraction, derivatization, and preconcentration were continuously performed. Several experimental parameters, such as the type and volume of extraction solvent, the type and volume of disperser, amount of derivatization reagent, microwave power, microwave irradiation time, pH of sample solution, and ionic strength were investigated and optimized. When the microwave power was 240 W, the analytes could be derivatized and extracted simultaneously within 90 s. The proposed method was applied to the analysis of river water, honey, milk, and pig plasma samples, and the recoveries of analytes obtained were in the range of 95.0-110.8, 95.4-106.3, 95.0-108.3, and 95.7-107.7, respectively. The relative standard deviations varied between 1.5% and 7.3% (n=5). The results showed that the proposed method was a rapid, convenient and feasible method for the determination of SAs in liquid samples. Copyright © 2011 Elsevier B.V. All rights reserved.

Liquid Crystal Colloids

Science.gov (United States)

Smalyukh, Ivan I.

2018-03-01

Colloids are abundant in nature, science, and technology, with examples ranging from milk to quantum dots and the colloidal atom paradigm. Similarly, liquid crystal ordering is important in contexts ranging from biological membranes to laboratory models of cosmic strings and liquid crystal displays in consumer devices. Some of the most exciting recent developments in both of these soft matter fields emerge at their interface, in the fast-growing research arena of liquid crystal colloids. Mesoscale self-assembly in such systems may lead to artificial materials and to structures with emergent physical behavior arising from patterning of molecular order and nano- or microparticles into precisely controlled configurations. Liquid crystal colloids show exceptional promise for new discovery that may impinge on composite material fabrication, low-dimensional topology, photonics, and so on. Starting from physical underpinnings, I review the state of the art in this fast-growing field, with a focus on its scientific and technological potential.

Comparing two tetraalkylammonium ionic liquids. I. Liquid phase structure

Energy Technology Data Exchange (ETDEWEB)

Lima, Thamires A.; Paschoal, Vitor H.; Faria, Luiz F. O.; Ribeiro, Mauro C. C., E-mail: mccribei@iq.usp.br [Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP (Brazil); Giles, Carlos [Departamento de Física da Matéria Condensada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP (Brazil)

2016-06-14

X-ray scattering experiments at room temperature were performed for the ionic liquids n-butyl-trimethylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1114}][NTf{sub 2}], and methyl-tributylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1444}][NTf{sub 2}]. The peak in the diffraction data characteristic of charge ordering in [N{sub 1444}][NTf{sub 2}] is shifted to longer distances in comparison to [N{sub 1114}][NTf{sub 2}], but the peak characteristic of short-range correlations is shifted in [N{sub 1444}][NTf{sub 2}] to shorter distances. Molecular dynamics (MD) simulations were performed for these ionic liquids using force fields available from the literature, although with new sets of partial charges for [N{sub 1114}]{sup +} and [N{sub 1444}]{sup +} proposed in this work. The shifting of charge and adjacency peaks to opposite directions in these ionic liquids was found in the static structure factor, S(k), calculated by MD simulations. Despite differences in cation sizes, the MD simulations unravel that anions are allowed as close to [N{sub 1444}]{sup +} as to [N{sub 1114}]{sup +} because anions are located in between the angle formed by the butyl chains. The more asymmetric molecular structure of the [N{sub 1114}]{sup +} cation implies differences in partial structure factors calculated for atoms belonging to polar or non-polar parts of [N{sub 1114}][NTf{sub 2}], whereas polar and non-polar structure factors are essentially the same in [N{sub 1444}][NTf{sub 2}]. Results of this work shed light on controversies in the literature on the liquid structure of tetraalkylammonium based ionic liquids.

Water quality for liquid wastes

International Nuclear Information System (INIS)

Mizuniwa, Fumio; Maekoya, Chiaki; Iwasaki, Hitoshi; Yano, Hiroaki; Watahiki, Kazuo.

1985-01-01

Purpose: To facilitate the automation of the operation for a liquid wastes processing system by enabling continuous analysis for the main ingredients in the liquid wastes accurately and rapidly. Constitution: The water quality monitor comprises a sampling pipeway system for taking out sample water for the analysis of liquid wastes from a pipeway introducing liquid wastes to the liquid wastes concentrator, a filter for removing suspended matters in the sample water and absorption photometer as a water quality analyzer. A portion of the liquid wastes is passed through the suspended matter filter by a feedpump. In this case, sulfate ions and chloride ions in the sample are retained in the upper portion of a separation color and, subsequently, the respective ingredients are separated and leached out by eluting solution. Since the leached out ingredients form ferric ions and yellow complexes respectively, their concentrations can be detected by the spectrum photometer. Accordingly, concentration for the sodium sulfate and sodium chloride in the liquid wastes can be analyzed rapidly, accurately and repeatedly by which the water quality can be determined rapidly and accurately. (Yoshino, Y.)

Mutual Fund Flight-to-Liquidity

DEFF Research Database (Denmark)

Rzeznik, Aleksandra

This paper examines the liquidity choices of mutual funds during times of market uncertainty. I find that when markets are uncertain, mutual funds actively increase the liquidity of their portfolio – often referred to as a ‘flight-to-liquidity.’ In aggregate, mutual fund behaviour has implications...... for the market; the market driven flight-toliquidity places upward pressure on the liquidity premium. I examine the underlying mechanisms driving fund behaviour. I show that market volatility is associated with lower fund performance and withdrawals, which causes funds to adjust the composition...... of their portfolio towards more liquid assets in order to meet potential redemptions. This causal chain is consistent with Vayanos (2004), who argues that fund managers are investors with time-varying liquidity preferences due to threat of withdrawal. Aggregated over funds, the effect is substantial: a one standard...

Mutual Fund Flight-to-Liquidity

DEFF Research Database (Denmark)

Rzeznik, Aleksandra

This paper examines the liquidity choices of mutual funds during times of market uncertainty. I find that when markets are uncertain, mutual funds actively increase the liquidity of their portfolio { often referred to as a `flight-to-liquidity.' In aggregate, mutual fund behaviour has implications...... for the market; the market driven flight-toliquidity places upward pressure on the liquidity premium. I examine the underlying mechanisms driving fund behaviour. I show that market volatility is associated with lower fund performance and withdrawals, which causes funds to adjust the composition...... of their portfolio towards more liquid assets in order to meet potential redemptions. This causal chain is consistent with Vayanos (2004), who argues that fund managers are investors with time-varying liquidity preferences due to threat of withdrawal. Aggregated over funds, the effect is substantial: a one standard...

Foil bearing performance in liquid nitrogen and liquid oxygen

Science.gov (United States)

Genge, Gary G.; Saville, Marshall; Gu, Alston

1993-01-01

Space transfer vehicles and other power and propulsion systems require long-life turbopumps. Rolling-element bearings used in current turbopumps do not have sufficient life for these applications. Process fluid foil bearings have established long life, with exceptional reliability, over a wide range of temperatures and fluids in many high-speed turbomachinery applications. However, actual data on bearing performance in cryogenic fluids has been minimal. The National Aeronautics and Space Administration (NASA) and AlliedSignal Aerospace Systems and Equipment (ASE) have attempted to characterize the leaf-type compliant foil bearing in oxygen and nitrogen. The work performed under a joint internal research and development program between Marshall Space Flight Center (MSFC) and ASE demonstrated that the foil bearing has load capacities of at least 266 psi in liquid oxygen and 352 psi in liquid nitrogen. In addition, the bearing demonstrated a direct damping coefficient of 40 to 50 lb-sec/in. with a damping ratio of .7 to 1.4 in. liquid nitrogen using a bearing sized for upper-stage turbopumps. With the results from this testing and the years of successful use in air cycle machines and other applications, leaf-type compliant foil bearings are ready for testing in liquid oxygen turbopumps.

Experimental study on desulfurization efficiency and gas-liquid mass transfer in a new liquid-screen desulfurization system

International Nuclear Information System (INIS)

Sun, Zhongwei; Wang, Shengwei; Zhou, Qulan; Hui, Shi'en

2010-01-01

This paper presents a new liquid-screen gas-liquid two-phase flow pattern with discarded carbide slag as the liquid sorbent of sulfur dioxide (SO 2 ) in a wet flue gas desulfurization (WFGD) system. On the basis of experimental data, the correlations of the desulfurization efficiency with flue gas flow rate, slurry flow rate, pH value of slurry and liquid-gas ratio were investigated. A non-dimensional empirical model was developed which correlates the mass transfer coefficient with the liquid Reynolds number, gas Reynolds number and liquid-gas ratio (L/G) based on the available experimental data. The kinetic reaction between the SO 2 and the carbide slag depends on the pressure distribution in this desulfurizing tower, gas liquid flow field, flue gas component, pH value of slurry and liquid-gas ratio mainly. The transient gas-liquid mass transfer involving with chemical reaction was quantified by measuring the inlet and outlet SO 2 concentrations of flue gas as well as the characteristics of the liquid-screen two-phase flow. The mass transfer model provides a necessary quantitative understanding of the hydration kinetics of sulfur dioxide in the liquid-screen flue gas desulfurization system using discarded carbide slag which is essential for the practical application. (author)

Liquid-Flow Controller With Trickle Preflow

Science.gov (United States)

Cox, George B., Jr.

1990-01-01

Liquid-flow controller allows pressure in liquid to increase steeply with flow as flow starts, then provides more-gradual nearly linear rise of pressure with flow as flow and pressure increase beyond preset breakpoint. Controller alternative version of mechanism described in "Liquid-Flow Controller Responds To Pressure" (MFS-28329) and "Liquid-Flow Controller With Preset Break Pressure" (MFS-28330). Material cut out of cone at tip of pintle. Liquid always passes from shell, albeit at low rate. When pressure in shell great enough to force orifice away from pintle, liquid flows at greater rate.

Liquid-vapour surface sensors for liquid nitrogen and hydrogen

Science.gov (United States)

Siegwarth, J. D.; Voth, R. O.; Snyder, S. M.

1992-01-01

The present paper identifies devices to serve as liquid-vapor detectors in zero gravity. The testing in LH2 was done in a sealed glass Dewar system to eliminate any chance of mixing H2 and air. Most of the tests were performed with the leads to the sensor horizontal. Some results of rapid cycle testing of LVDG in LH2 are presented. Findings of rapid-cycle testing of LVDG in LH2 are discussed. The sensor crossed the liquid surface when the position sensor registered 1.9 V, which occurred at about 0.4075 s. The delay time was about 1.5 ms. From the estimated slope of the position sensor curve at 1.9 V, the velocity of the sensor through the liquid surface is over 3 m/s. Results of tests of optical sensors are presented as well.

Liquidity regulation and bank behavior

OpenAIRE

Bonner, C.

2014-01-01

In response to the 2007-08 financial crisis, the Basel Committee on Banking Supervision proposed two liquidity standards to reinforce banks’ resilience to liquidity risks. The purpose of this thesis is to analyze the impact of liquidity regulation on bank behavior. The first of four main chapters analyzes the development of global liquidity standards, their objectives as well as their interaction with capital standards. The analysis suggests that regulating capital is associated with declinin...

Structural design of liquid oxygen/liquid methane robotic lander JANUS

Science.gov (United States)

Chaidez, Mariana

As the attempt to send humans to Mars has gained momentum in the last decade, the need to find alternative propellants that are safer, less toxic, and yields a better performance has become apparent [1]. Liquid methane and oxygen have emerged as a suitable alternative. In addition, the incorporation of liquid methane/liquid oxygen into the propulsion system has demonstrated an increase in engine performance, as well as a reduction in the volume, size and complexity of the propulsion system. In an attempt to further understand the technologies that are possible to develop using liquid oxygen (LO 2) and liquid methane (LCH4), a preliminary design of a robotic lander JANUS is being completed by the Center for Space Exploration and Technology Research (cSTER). The structural design of the vehicle is important because it acts as the skeleton of the vehicle and dictates the maneuverability of the robotic lander. To develop the structure of the robotic lander, six different design vehicle concepts with varying tank configurations were considered. Finite Element Analysis (FEA) was completed on each model to optimize each vehicle. Trade studies were completed to choose the best design for JANUS. Upon completion of the trade studies the design for the first prototype of JANUS was initiated in which the tank and thrust modules were designed. This thesis will describe the design process for the structural design of the JANUS.

Harvesting contaminants from liquid

Science.gov (United States)

Simpson, John T.; Hunter, Scott R.

2016-05-31

Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

Liquidity and International Trade

OpenAIRE

Rodriguez-Lopez, Antonio

2016-01-01

This paper introduces a framework to study the links between the supply of liquid assets for the financial market and the international allocation of economic activity. Private assets’ liquidity properties - their usefulness as collateral or media of exchange in financial transactions - affect assets’ values and interest rates, with consequences on firm entry, production, aggregate productivity, and total market capitalization. In a closed economy, the liquidity market increases the size and ...

Core-softened fluids, water-like anomalies, and the liquid-liquid critical points.

Science.gov (United States)

Salcedo, Evy; de Oliveira, Alan Barros; Barraz, Ney M; Chakravarty, Charusita; Barbosa, Marcia C

2011-07-28

Molecular dynamics simulations are used to examine the relationship between water-like anomalies and the liquid-liquid critical point in a family of model fluids with multi-Gaussian, core-softened pair interactions. The core-softened pair interactions have two length scales, such that the longer length scale associated with a shallow, attractive well is kept constant while the shorter length scale associated with the repulsive shoulder is varied from an inflection point to a minimum of progressively increasing depth. The maximum depth of the shoulder well is chosen so that the resulting potential reproduces the oxygen-oxygen radial distribution function of the ST4 model of water. As the shoulder well depth increases, the pressure required to form the high density liquid decreases and the temperature up to which the high-density liquid is stable increases, resulting in the shift of the liquid-liquid critical point to much lower pressures and higher temperatures. To understand the entropic effects associated with the changes in the interaction potential, the pair correlation entropy is computed to show that the excess entropy anomaly diminishes when the shoulder well depth increases. Excess entropy scaling of diffusivity in this class of fluids is demonstrated, showing that decreasing strength of the excess entropy anomaly with increasing shoulder depth results in the progressive loss of water-like thermodynamic, structural and transport anomalies. Instantaneous normal mode analysis was used to index the overall curvature distribution of the fluid and the fraction of imaginary frequency modes was shown to correlate well with the anomalous behavior of the diffusivity and the pair correlation entropy. The results suggest in the case of core-softened potentials, in addition to the presence of two length scales, energetic, and entropic effects associated with local minima and curvatures of the pair interaction play an important role in determining the presence of water

Prediction of (liquid + liquid) equilibrium for binary and ternary systems containing ionic liquids with the bis[(trifluoromethyl)sulfonyl]imide anion using the ASOG method

International Nuclear Information System (INIS)

Robles, Pedro A.; Cisternas, Luis A.

2015-01-01

Highlights: • ASOG model was used to predict LLE data for ionic liquid systems. • Twenty five binary and seven ternary systems that include the NTf 2 anion were used. • New group interaction parameters were determined. • The results are satisfactory, with rms deviations of about 3%. - Abstract: Ionic liquids are neoteric, environmentally friendly solvents (as they do not produce emissions) composed of large organic cations and relatively small inorganic anions. They have favorable physical properties, such as negligible volatility and a wide range of liquid existence. (Liquid + liquid) equilibrium (LLE) data for systems including ionic liquids, although essential for the design, optimization and operation of separation processes, remain scarce. However, some recent studies have presented ternary LLE data involving several ionic liquids and organic compounds such as alkanes, alkenes, alkanols, ethers and aromatics, as well as water. In this work, the ASOG model for the activity coefficient is used to predict LLE data for 25 binary and 07 ternary systems at 101.3 kPa and several temperatures; all the systems are formed by ionic liquids including the bis[(trifluoromethyl)sulfonyl]imide (NTf 2 ) anion plus alkanes, alkenes, cycloalkanes, alkanols, water, thiophene and aromatics. New group interaction parameters were determined using a modified Simplex method, minimizing a composition-based objective function of experimental data obtained from the literature. The results are satisfactory, with rms deviations of approximately 3%

Successful vitrification of bovine immature oocyte using liquid helium instead of liquid nitrogen as cryogenic liquid.

Science.gov (United States)

Yu, Xue-Li; Xu, Ya-Kun; Wu, Hua; Guo, Xian-Fei; Li, Xiao-Xia; Han, Wen-Xia; Li, Ying-Hua

2016-04-01

The objectives of this study were to compare the effectiveness of liquid helium (LHe) and liquid nitrogen (LN2) as cryogenic liquid for vitrification of bovine immature oocytes with open-pulled straw (OPS) system and determine the optimal cryoprotectant concentration of LHe vitrification. Cumulus oocyte complexes were divided into three groups, namely, untreated group (control), LN2 vitrified with OPS group, and LHe vitrified with OPS group. Oocyte survival was assessed by morphology, nuclear maturation, and developmental capability. Results indicated that the rates of normal morphology, maturation, cleavage, and blastocyst (89.3%, 52.8%, 42.7%, and 10.1%, respectively) in the LHe-vitrified group were all higher than those (79.3%, 43.4%, 34.1%, and 4.7%) in the LN2-vitrified group (P 0.05). The maturation rate of the EDS35 group (65.0%) was higher than those of the EDS30 (51.3%), EDS40 (50.1%), EDS45 (52.1%), and EDS50 groups (36.9%; P liquid for vitrification of bovine immature oocytes, and it is more efficient than LN2-vitrified oocytes in terms of blastocyst production. EDS35 was the optimal cryoprotectant agent combination for LHe vitrification in this study. Copyright © 2016 Elsevier Inc. All rights reserved.

Functional ionic liquids

International Nuclear Information System (INIS)

Baecker, Tobias

2012-01-01

In the thesis at hand, new functional ionic liquids were investigated. Main focus was attended to their structure property relations and the structural features leading to a decrease of the melting point. New compounds of the type 1-butyl-3-methylimidazolium tris(N,Ndialkyldithiocarbamato) uranylate with variously substituated dithiocarbamato ligands were synthesized and characterized. Ligands with asymmetrical substitution pattern proved to be most suitable for ionic liquid formation. The single-crystal X-ray structures revealed the interactions in the solid state. Here, the first spectroscopic investigation of the U-S bond in sulfur donated uranyl complexes, up to now only observed in single-crystal X-ray structures, is presented, and the participation of the uranium f-orbitals is shown by theoretical calculations. Electrochemical investigations showed the accessibility of the respective U V O 2 + compounds. As well, ionic liquids with [FeCl 4 ] - and [Cl 3 FeOFeCl 3 ] 2- as anion were synthesized. Both of these anions contain high-spin Fe(III) centres in distorted tetrahedral environment, but exhibit different magnetic behaviour. The tetrachloroferrates show the usual paramagnetism, the m-oxobis(trichloroferrate) exhibits unexpectedly strong antiferromagnetic coupling, as was observed by NMR experiments and susceptibility measurements. To investigate structure-property relations in functionalized ionic liquids, a set of protic, primary alkylammonium and aprotic, quarternary trimethylalkylammonium based ionic liquids was synthesized, and characterized. The length of the alkyl chain was systematically varied, and all compounds were synthesized with and without hydroxyl group, as well as formate and bis(triflyl)amide salts, aiming at getting insight into the influence of the different structure parts on the respective ionic liquid's properties.

(Liquid + liquid) equilibrium at T = 298.15 K for ternary mixtures of alkane + aromatic compounds + imidazolium-based ionic liquids

International Nuclear Information System (INIS)

Domínguez, Irene; Requejo, Patricia F.; Canosa, José; Domínguez, Ángeles

2014-01-01

Highlights: • The LLE ternary phase diagrams with 2 imidazolium-based ionic liquids were measured. • The LLE data were experimental determined at T = 298.15 K and p = 1 atm. • Mixtures of (octane or nonane) and (benzene or toluene or ethylbenzene) were studied. • LLE experimental data were correlated with NRTL and UNIQUAC thermodynamic models. - Abstract: Ionic liquids, with their unique and tunable properties, can be an advantageous alternative as extractive solvents in separation processes involving systems containing aliphatic and aromatic hydrocarbons. In this work, (liquid + liquid) equilibrium (LLE) data for the ternary systems {nonane (1) + benzene (2) + 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMim][NTf 2 ] (3)}, {octane (1) + benzene (2) + 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, [PMim][NTf 2 ] (3)}, and {nonane (1) + aromatic compound (benzene or toluene or ethylbenzene) (2) + [PMim][NTf 2 ] (3)} were determined at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio, derived from the equilibrium data, were used to determine if this ionic liquid can be considered as a potential solvent for the separation of aromatic compounds (benzene, toluene, and ethylbenzene) from alkanes (octane and nonane). The experimental data were satisfactorily correlated with NRTL and UNIQUAC models

What Is a Simple Liquid?

Directory of Open Access Journals (Sweden)

Trond S. Ingebrigtsen

2012-03-01

Full Text Available This paper is an attempt to identify the real essence of simplicity of liquids in John Locke’s understanding of the term. Simple liquids are traditionally defined as many-body systems of classical particles interacting via radially symmetric pair potentials. We suggest that a simple liquid should be defined instead by the property of having strong correlations between virial and potential-energy equilibrium fluctuations in the NVT ensemble. There is considerable overlap between the two definitions, but also some notable differences. For instance, in the new definition simplicity is not a direct property of the intermolecular potential because a liquid is usually only strongly correlating in part of its phase diagram. Moreover, not all simple liquids are atomic (i.e., with radially symmetric pair potentials and not all atomic liquids are simple. The main part of the paper motivates the new definition of liquid simplicity by presenting evidence that a liquid is strongly correlating if and only if its intermolecular interactions may be ignored beyond the first coordination shell (FCS. This is demonstrated by NVT simulations of the structure and dynamics of several atomic and three molecular model liquids with a shifted-forces cutoff placed at the first minimum of the radial distribution function. The liquids studied are inverse power-law systems (r^{-n} pair potentials with n=18,6,4, Lennard-Jones (LJ models (the standard LJ model, two generalized Kob-Andersen binary LJ mixtures, and the Wahnstrom binary LJ mixture, the Buckingham model, the Dzugutov model, the LJ Gaussian model, the Gaussian core model, the Hansen-McDonald molten salt model, the Lewis-Wahnstrom ortho-terphenyl model, the asymmetric dumbbell model, and the single-point charge water model. The final part of the paper summarizes properties of strongly correlating liquids, emphasizing that these are simpler than liquids in general. Simple liquids, as defined here, may be

Surface wave propagation in a double liquid layer over a liquid ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

Abstract. The frequency equation is derived for surface waves in a liquid- saturated porous half-space supporting a double layer, that of inhomogeneous and homogeneous liquids. Asymptotic approximations of Bessel functions are used for long and short wavelength cases. Certain other problems are discussed as spe-.

Indication of liquid-liquid phase transition in CuZr-based melts

DEFF Research Database (Denmark)

Zhou, C.; Hu, L.N.; Sun, Q.J.

2013-01-01

We study the dynamic behavior of CuZr-based melts well above the liquidus temperature. The results show a discontinuous change in viscosity during cooling, which is attributed to an underlying liquid-liquid phase transition (LLPT) in these melts. The LLPT is further verified by thermodynamic...

Liquid-liquid reductive extraction in molten fluoride salt/liquid aluminium as a core of process for the An/Ln group separation

International Nuclear Information System (INIS)

Conocar, O.

2007-06-01

This report concerns a pyrochemical process based on liquid-liquid extraction in a molten fluoride/liquid aluminium system as a core process for actinide (An)/lanthanide (Ln) group separation, studied at CEA. The basic and demonstrative experiments have established the feasibility of the An/Ln group separation in the molten fluoride/liquid aluminium system (U, Pu, Np, Am, Cm traces from Nd, Ce, Eu, Sm, Eu, La - An/Ln separation factors over 1000 - An recovery yield over 98 % in one batch). The main experimental efforts must now be targeted on the recovery of actinides from the Al matrix. A thermodynamic and bibliographical survey has been done. It shows that back-extraction in a molten chloride melt could be a promising technique for this purpose

Liquid-liquid reductive extraction in molten fluoride salt/liquid aluminium as a core of process for the An/Ln group separation

Energy Technology Data Exchange (ETDEWEB)

Conocar, O

2007-06-15

This report concerns a pyrochemical process based on liquid-liquid extraction in a molten fluoride/liquid aluminium system as a core process for actinide (An)/lanthanide (Ln) group separation, studied at CEA. The basic and demonstrative experiments have established the feasibility of the An/Ln group separation in the molten fluoride/liquid aluminium system (U, Pu, Np, Am, Cm traces from Nd, Ce, Eu, Sm, Eu, La - An/Ln separation factors over 1000 - An recovery yield over 98 % in one batch). The main experimental efforts must now be targeted on the recovery of actinides from the Al matrix. A thermodynamic and bibliographical survey has been done. It shows that back-extraction in a molten chloride melt could be a promising technique for this purpose.

Method of processing radioactive liquid wastes

International Nuclear Information System (INIS)

Kurumada, Norimitsu; Shibata, Setsuo; Wakabayashi, Toshikatsu; Kuribayashi, Hiroshi.

1984-01-01

Purpose: To facilitate the procession of liquid wastes containing insoluble salts of boric acid and calcium in a process for solidifying under volume reduction of radioactive liquid wastes containing boron. Method: A soluble calcium compound (such as calcium hydroxide, calcium oxide and calcium nitrate) is added to liquid wastes whose pH value is adjusted neutral or alkaline such that the molar ratio of calcium to boron in the liquid wastes is at least 0.2. Then, they are agitated at a temperature between 40 - 70 0 C to form insoluble calcium salt containing boron. Thereafter, the liquid is maintained at a temperature less than the above-mentioned forming temperature to age the products and, thereafter, the liquid is evaporated to condensate into a liquid concentrate containing 30 - 80% by weight of solid components. The concentrated liquid is mixed with cement to solidify. (Ikeda, J.)

Rollover risk, liquidity and macroprudential regulation

OpenAIRE

Ahnert, Toni

2014-01-01

I study rollover risk in the wholesale funding market when intermediaries can hold liquidity ex ante and are subject to fire sales ex post. Precautionary liquidity restores multiple equilibria in a global rollover game. An intermediate liquidity level supports both the usual run equilibrium and an efficient equilibrium. I provide a uniqueness refinement to characterize the privately optimal liquidity choice. Because of fire sales, liquidity holdings are strategic substitutes. Intermediaries f...

Contextual factors in liquidity risk

NARCIS (Netherlands)

Bonner, C.; van Lelyveld, I.P.P.; Zymek, R.

2015-01-01

We assess the determinants of banks’ liquidity holdings using data for nearly 7000 banks from 25 OECD countries. We highlight the role of several bank-specific, institutional and policy variables in shaping banks’ liquidity risk management. Our main question is whether liquidity regulation

Liquidity management through financial planning

OpenAIRE

Kameníková Katarína

2001-01-01

One of the basic goals of financial management is to provide financial property and capital for running of the firm, as well as for its development, that means provide optimal firm´s liquidity.To improve liquidity is possible provide through various ways. In present time there is increasing importance of financial planning., where planning of liquidity presents one of its integral part. Therefore I deal in presented paper with possible liquidity improvement through calculation of financial pl...

Shallow Water Tuned Liquid Dampers

DEFF Research Database (Denmark)

Krabbenhøft, Jørgen

that for realistic roughness parameters the bottom friction has very limited effect on the liquid sloshing behavior and can be neglected. Herby the postulate is verified. Based on the mathematical model three dimensionless parameters are derived showing that the response of the damper depends solely on ratio......The use of sloshing liquid as a passive means of suppressing the rolling motion of ships was proposed already in the late 19th century. Some hundred years later the use of liquid sloshing devices, often termed Tuned Liquid Dampers (TLD), began to find use in the civil engineering community....... The TLDs studied in this thesis essentially consist of a rectangular container partially filled with liquid in the form of plain tap water. The frequency of the liquid sloshing motion, which is adjusted by varying the length of the tank and the depth of the wa- ter, is tuned to the structural frequency...

Effect of surfactant Te on the behavior of alumina inclusions at advancing solid-liquid interfaces of liquid steel

International Nuclear Information System (INIS)

Zheng, Lichun; Malfliet, Annelies; Wollants, Patrick; Blanpain, Bart; Guo, Muxing

2016-01-01

The effect of surfactant Te on the behavior of alumina inclusions at advancing solid-liquid interfaces of liquid steel was studied by adding Te to liquid steel before Al deoxidation at 1873 K. After water-quenching, the spatial distribution homogeneity of alumina inclusions in the steel matrix was characterized using the Dirichlet tessellation method. The deterioration of this homogeneity with increasing the addition of Te indicates that Te facilitates pushing of alumina inclusions. This phenomenon was discussed based on the thermodynamics of an asymmetric thin liquid film confined by an advancing solid-liquid interface and a particle. The surface excesses of Te at the solid-liquid and particle-liquid interfaces were theoretically demonstrated to decrease when an alumina inclusion moves towards the solid-liquid interface, thereby weakening the effect of Te on the solid-liquid and particle-liquid interfacial energies. Based on this, effect of surfactants was incorporated in the models predicting the critical velocity V_C.

Liquid Rocket Engine Testing

Science.gov (United States)

2016-10-21

Briefing Charts 3. DATES COVERED (From - To) 17 October 2016 – 26 October 2016 4. TITLE AND SUBTITLE Liquid Rocket Engine Testing 5a. CONTRACT NUMBER...298 (Rev. 8-98) Prescribed by ANSI Std. 239.18 Liquid Rocket Engine Testing SFTE Symposium 21 October 2016 Jake Robertson, Capt USAF AFRL...Distribution Unlimited. PA Clearance 16493 Liquid Rocket Engine Testing • Engines and their components are extensively static-tested in development • This

Recent development of ionic liquid membranes

Directory of Open Access Journals (Sweden)

Junfeng Wang

2016-04-01

Full Text Available The interest in ionic liquids (IL is motivated by its unique properties, such as negligible vapor pressure, thermal stability, wide electrochemical stability window, and tunability of properties. ILs have been highlighted as solvents for liquid–liquid extraction and liquid membrane separation. To further expand its application in separation field, the ionic liquid membranes (ILMs and its separation technology have been proposed and developed rapidly. This paper is to give a comprehensive overview on the recent applications of ILMs for the separation of various compounds, including organic compounds, mixed gases, and metal ions. Firstly, ILMs was classified into supported ionic liquid membranes (SILMs and quasi-solidified ionic liquid membranes (QSILMs according to the immobilization method of ILs. Then, preparation methods of ILMs, membrane stability as well as applications of ILMs in the separation of various mixtures were reviewed. Followed this, transport mechanisms of gaseous mixtures and organic compounds were elucidated in order to better understand the separation process of ILMs. This tutorial review intends to not only offer an overview on the development of ILMs but also provide a guide for ILMs preparations and applications. Keywords: Ionic liquid membrane, Supported ionic liquid membrane, Qusai-solidified ionic liquid membrane, Stability, Application

Acid digestion of organic liquids

International Nuclear Information System (INIS)

Partridge, J.A.; Bosuego, G.P.

1980-10-01

Laboratory studies on the destruction of liquid organic wastes by acid digestion are discussed. A variety of liquid waste types was tested, including those encountered in the nuclear industry as well as some organic liquids representative of non-nuclear industrial wastes. The liquids tested were vacuum pump oil, tri-n-butyl phosphate (TBP), normal paraffin hydrocarbon solvent (NPH), a mixture of 30 vol% TBP in NPH, carbon tetrachloride (CCl 4 ), trichloroethane, toluene, hexone (methyl isobutyl ketone), a mixture of hexone and NPH, polychlorobiphenyl (PCB), isopropanol, normal-decane, and two waste organic solutions from Hanford radioactive waste tanks. The tests demonstrated that several types of organic liquids can be destroyed by the acid digestion process. 8 figures, 19 tables

Magnetically focused liquid drop radiator

Science.gov (United States)

Botts, Thomas E.; Powell, James R.; Lenard, Roger

1986-01-01

A magnetically focused liquid drop radiator for application in rejecting rgy from a spacecraft, characterized by a magnetizable liquid or slurry disposed in operative relationship within the liquid droplet generator and its fluid delivery system, in combination with magnetic means disposed in operative relationship around a liquid droplet collector of the LDR. The magnetic means are effective to focus streams of droplets directed from the generator toward the collector, thereby to assure that essentially all of the droplets are directed into the collector, even though some of the streams may be misdirected as they leave the generator. The magnetic focusing means is also effective to suppress splashing of liquid when the droplets impinge on the collector.

Liquidity coinsurance and bank capital

NARCIS (Netherlands)

Castiglionesi, F.; Feriozzi, F.; Lóránth, G.; Pelizzon, L.

Banks can deal with their liquidity risk by holding liquid assets (self-insurance), by participating in interbank markets (coinsurance), or by using flexible financing instruments, such as bank capital (risk sharing). We use a simple model to show that undiversifiable liquidity risk, that is, the

Risk allocation under liquidity constraints

NARCIS (Netherlands)

Csóka, P.; Herings, P.J.J.

2013-01-01

Risk allocation games are cooperative games that are used to attribute the risk of a financial entity to its divisions. In this paper, we extend the literature on risk allocation games by incorporating liquidity considerations. A liquidity policy specifies state-dependent liquidity requirements that

Plasmas in Multiphase Media: Bubble Enhanced Discharges in Liquids and Plasma/Liquid Phase Boundaries

Energy Technology Data Exchange (ETDEWEB)

Kushner, Mark Jay [University of Michigan

2014-07-10

In this research project, the interaction of atmospheric pressure plasmas with multi-phase media was computationally investigated. Multi-phase media includes liquids, particles, complex materials and porous surfaces. Although this investigation addressed fundamental plasma transport and chemical processes, the outcomes directly and beneficially affected applications including biotechnology, medicine and environmental remediation (e.g., water purification). During this project, we made advances in our understanding of the interaction of atmospheric pressure plasmas in the form of dielectric barrier discharges and plasma jets with organic materials and liquids. We also made advances in our ability to use computer modeling to represent these complex processes. We determined the method that atmospheric pressure plasmas flow along solid and liquid surfaces, and through endoscopic like tubes, deliver optical and high energy ion activation energy to organic and liquid surfaces, and produce reactivity in thin liquid layers, as might cover a wound. We determined the mechanisms whereby plasmas can deliver activation energy to the inside of liquids by sustaining plasmas in bubbles. These findings are important to the advancement of new technology areas such as plasma medicine

Recent development of ionic liquid membranes

OpenAIRE

Wang, Junfeng; Luo, Jianquan; Feng, Shicao; Li, Haoran; Wan, Yinhua; Zhang, Xiangping

2016-01-01

The interest in ionic liquids (IL) is motivated by its unique properties, such as negligible vapor pressure, thermal stability, wide electrochemical stability window, and tunability of properties. ILs have been highlighted as solvents for liquidâliquid extraction and liquid membrane separation. To further expand its application in separation field, the ionic liquid membranes (ILMs) and its separation technology have been proposed and developed rapidly. This paper is to give a comprehensive ov...

Advances in gas-liquid flows 1990

International Nuclear Information System (INIS)

Kim, J.M.; Hashemi, A.

1990-01-01

Gas-liquid two-phase flows commonly occur in nature and industrial applications. Rain, clouds, geysers, and waterfalls are examples of natural gas-liquid flow phenomena, whereas industrial applications can be found in nuclear reactors, steam generators, boilers, condensers, evaporators, fuel atomization, heat pipes, electronic equipment cooling, petroleum engineering, chemical process engineering, and many others. The household-variety phenomena such as garden sprinklers, shower, whirlpool bath, dripping faucet, boiling tea pot, and bubbling beer provide daily experience of gas-liquid flows. The papers presented in this volume reflect the variety and richness of gas-liquid two-phase flow and the increasing role it plays in modern technology. This volume contains papers dealing with some recent development in gas-liquid flow science and technology, covering basic gas-liquid flows, measurements and instrumentation, cavitation and flashing flows, countercurrent flow and flooding, flow in various components and geometries liquid metals and thermocapillary effects, heat transfer, nonlinear phenomena, instability, and other special and general topics related to gas-liquid flows

Plate performance in liquid-liquid extraction

International Nuclear Information System (INIS)

Wadkins, R.P.

1984-01-01

The relative effectiveness of perforated, nozzle, and burred plates from a capacity and extraction standpoint were studied in a pulsed liquid-liquid extraction system. The experiments were conducted in a 3.8 x 10 -2 m diameter column using a mixture of aluminum nitrate, nitric acid, and uranyl nitrate as the aqueous phase, and tributyl phosphate dissolved in AMSCO 125-90 W as the organic phase. The uranium was extracted from the aqueous phase to the organic phase. A standard cartridge was made for each type of plate and consisted of an assembly of plates spaced 5.08 x 10 -2 m apart. Each plate had 3.2 x 10 -3 m holes spaced on 6.1 x 10 -3 -m centers, and contained 23% free area. 16 references, 4 figures, 1 table

78 FR 12310 - Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011

Science.gov (United States)

2013-02-22

... dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), hydrofluorocarbons (HFC), perfluorocarbons (PFC..., petrochemical production, phosphoric acid, titanium dioxide, lime production, and several fluorinated gas...

Comment on "Spontaneous liquid-liquid phase separation of water"

Science.gov (United States)

Limmer, David T.; Chandler, David

2015-01-01

Yagasaki et al. [Phys. Rev. E 89, 020301 (2014), 10.1103/PhysRevE.89.020301] present results from a molecular dynamics trajectory illustrating coarsening of ice, which they interpret as evidence of transient coexistence between two distinct supercooled phases of liquid water. We point out that neither two distinct liquids nor criticality are demonstrated in this simulation study. Instead, the illustrated trajectory is consistent with coarsening behaviors analyzed and predicted in earlier work by others.

Fluctuating hydrodynamics for ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Lazaridis, Konstantinos [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States); Wickham, Logan [Department of Computer Science, Washington State University, Richland, 99354 (United States); Voulgarakis, Nikolaos, E-mail: n.voulgarakis@wsu.edu [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States)

2017-04-25

We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau–Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids. - Highlights: • A new fluctuating hydrodynamics method for ionic liquids. • Description of ionic liquid morphology in bulk and near electrified surfaces. • Direct comparison with experimental measurements.

Hidden Liquidity

OpenAIRE

Cebiroglu, Gökhan; Horst, Ulrich

2012-01-01

We cross-sectionally analyze the presence of aggregated hidden depth and trade volume in the S&P 500 and identify its key determinants. We find that the spread is the main predictor for a stock’s hidden dimension, both in terms of traded and posted liquidity. Our findings moreover suggest that large hidden orders are associated with larger transaction costs, higher price impact and increased volatility. In particular, as large hidden orders fail to attract (latent) liquidity to the market, hi...