Electrochemical behavior of graphite anode during anode effect in cryolite molten salts

Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is considered that a type of oxyfluoroaliminate complex anions reacts with carbon to form a high-resistance CF film on the anode surface at a high potential. The passivation potential is 3.28 V in 0.5% alumina-containing electrolyte, and the passivation potential increases with alumina content increasing which indicates that the alumina content determines the anodic process in the cryolite-alumina molten salt system.

Electroanalytical Study of Electrode Processes on Carbon Anode in Lithium Fluoride and Neodymium Fluoride Melt

The anode processes of carbon electrode in LiF-70%NdF3 melt were studied by electroanalytical techniques, including cyclic voltammetry(CV) and chronoamperometry(CA). Anode gases were analyzed by gas chromatography(GC) on-line during controlled-potential electrolysis. Two anode peaks were observed. The first process starting at 2.0 V vs Li+/Li was corresponded to the discharge of residual oxide ions, with the generation of CO and CO2. The discharge of fluoride ions occurred at the potentials higher than 4.3 V vs Li+/Li, with the generation of a small amount of CF4 and C2F6, accompanied by a sudden drop in current, marking the onset of the anode effect. The second process occurred when the potential exceeded 5.5 V vs Li+/Li, with the generation of a large amount of CF4 and C2F6. When the temperature was changed from 1173 to 1273 K, the current of the second process decreased, leading to a stable anode effect.

Study on the Electro-reduction of Perfluorodecalin

The reduction of perfluorodecalin was studied by the method of electrochemistry. The results indicated that the electrochemical reduction of perfluorodecalin was a multi-step reaction. The mechanism of the first consecutive reaction showed that it is to diffusion controlling step.

Microscopic mechanism of perfluorocarbon gas formation in aluminum electrolysis process

In view of the unclear cause of perfluorocarbons(PFCs)emission in the anode effect stage of aluminum electrolysis,the microscopic formation mechanism of PFCs was studied by density functional theory calculation and X-ray photoelectron spectroscopy(XPS).It is found that the discharge of fluorine containing anions([F]−)on carbon anode first causes the substitution of C—H by C—F and further results in the saturation of aromatic C—C bonds,leading to the appearance of—CF_(3)or—C_(2)F_(5)group through six-carbon-ring opening.Elimination of—CF_(3)and—C_(2)F_(5) with F atom could be a likely mechanism of CF_(4) and C_(2)F_(6) formation.XPS results confirm that different types of—CF_(x) group can be formed on anode surface during electrolysis,and the possibility that[F]−discharges continuously at the C edge and finally forms different C—F bonds in quantum mechanical calculation was verified.

Recent Advances in ^(19)Fluorine Magnetic Resonance Imaging with Perfluorocarbon Emulsions

The research roots of 19fluorine （19F） magnetic resonance imaging （MRI） date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, 19F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of 19F imaging has exploded. In part, this is due to advances in MRI instrumentation, ~gF/1H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of ~gF into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents.

Development of a hydrogen peroxide-responsive and oxygen-carrying nanoemulsion for photodynamic therapy against hypoxic tumors using phase inversion composition method

Photodynamic therapy(PDT)has become an attractive tumor treatment modality because of its noninvasive feature and low side effects.However,extreme hypoxia inside solid tumors severely impedes PDT therapeutic outcome.To overcome this obstacle,various strategies have been developed recently.Among them,in situ oxygen generation,which relies on the decom-position of tumor endogenous H_(2)O_(2),and oxygen delivery tactic using high oxygen loading capacity of hemoglobin or perfluorocarbons,have been widely studied.The in situ oxygen generation strategy has high specificity to tumors,but its oxygen-generating efficiency is lim-ited by the intrinsically low tumor H_(2)O_(2)level.In contrast,the oxygen delivery approach holds advantage of high oxygen loading efficiency,nevertheless lacks tumor specificity.In this work,we prepared a nanoemulsion system containing H_(2)O_(2)-responsive catalase,highly efficient ox-ygen carrier perfiuoropolyether(PFPE),and a near-infrared(NIR)light activatable photo-sensitizer IR780,to combine the high tumor specificity of the in situ oxygen generation strategy and the high efficiency of the oxygen delivery strategy.This concisely prepared nanoplatform exhibited enhanced and H_(2)O_(2)-controllable production of singlet oxygen under light excitation,satisfactory cytocompatibility,and ability to kill cancer cells under NIR light excitation.This highlights the potential of this novel nanoplatform for highly efficient and selective NIR light mediated PDT against hypoxic tumors.This research provides new insight into the design of intelligent nanoplatform for relieving tumor hypoxia and enhancing the oxygen-dependent PDT effects in hypoxic tumors.

New technique for removal of perfluorocarbon liquid related sticky silicone oil and literature review

AIM:To investigate the safety and efficacy of sticky silicone oil(SSO)removal using a 22-gauge vein detained needle and inner limiting membrane(ILM)wrap-and-peel technique.METHODS:This retrospective consecutive case series reviewed the records of patients with a history of retinal detachment who had received silicone oil and perfluorocarbon liquid(PFCL)as intraocular tamponades.Patients were included in the analysis if they exhibited SSO remnants during silicone oil removal.The aspiration of most of the SSO remnants was performed by a 22-gauge vein detained needle.The small amounts of droplets adhered to the macula and epi-macular membrane were subsequently removed by the ILM warp-and-peel technique.The anatomical and functional outcomes,and postoperative complications were recorded.In vitro experiments were performed to simulate the formation of SSO remnants in four groups.RESULTS:Of 711 patients who underwent silicone oil removal during the study period,9 patients exhibited SSO remnants and underwent follow-up for at least 3mo.Seven eyes(78%)underwent the ILM wrap-and-peel technique to completely remove small droplets of SSO that were glued to the macula and epi-macular membrane.No obvious complications occurred.Postoperative optical coherence tomography revealed normal retinal structure in all patients.In vitro analyses showed that balanced salt solution and prolonged vibration(for 1wk)had the strongest effects on silicone oil and PFCL compound opacities.CONCLUSION:SSO remnants could be removed in an intact manner and without complications,using a vein detained needle-assisted and ILM wrap-and-peel technique.The findings suggest that PFCL and infusion fluid should be completely removed before silicone oil injection to prevent SSO formation.

Synthesis of Calcium Phosphate Controllable Coating Thickness on Oil-in-Water Nanoemulsion with Performance of Oxygen Release as Oxygen Carrier

Perfluorocarbon emulsion has been studied as an oxygen carrier, due to its high oxygen content. In clinical trials, it has shown stability in delivering oxygen to the target region. The purpose of the present study was to increase the stability of the emulsion by coating its surface with calcium phosphate. A layer-by-layer method was employed to coat the flexible emulsion surface. Considering the ionic affinity of calcium and phosphate to the lecithin emulsion surface, the first layer of coating was calcium and the second layer was comprised of phosphate ion. The coated emulsion demonstrated various oxygen release times depending on the thickness of the layers: from 0.04 sec. for a thickness of 8 nm to 0.17 sec. for a thickness 38 nm. Overall, the stability of the calcium phosphate coated emulsion was increased, while its original function as an oxygen carrier was maintained.

Etching characteristics of thin SiON films using a liquefied perfluorocarbon precursor of C_6F_(12)O with a low global warming potential

Perfluorocarbon gas is widely used in the semiconductor industry.However,perfluorocarbon has a negative effect on the global environment owing to its high global warming potential(GWP) value.An alternative solution is essential.Therefore,we evaluated the possibility of replacing conventional perfluorocarbon etching gases such as CHF_3 with C_6F_(12)O,which has a low GWP and is in a liquid state at room temperature.In this study,silicon oxynitride(SiON) films were plasma-etched using inductively coupled CF4+C_6F_(12)O+O_2 mixed plasmas.Subsequently,the etching characteristics of the film,such as etching rate,etching profile,selectivity over Si,and photoresist,were investigated.A double Langmuir probe was used and optical emission spectroscopy was performed for plasma diagnostics.In addition,a contact angle goniometer and x-ray photoelectron spectroscope were used to confirm the change in the surface properties of the etched SiON film surface.Consequently,the etching characteristics of the C_6F_(12)O mixed plasma exhibited a lower etching rate,higher SiON/Si selectivity,lower plasma damage,and more vertical etched profiles than the conventional CHF_3 mixed plasma.In addition,the C_6F_(12)O gas can be recovered in the liquid state,thereby decreasing global warming.These results confirmed that the C_6F_(12)O precursor can sufficiently replace the conventional etching gas.

Reperfusion injury after critical intestinal ischemia and its correction with perfluorochemical emulsion "perftoran"

AIM： To investigate the anti-ischemic properties of perfluorochemical emulsion ＂perftoran＂ in mesenteric region. METHODS： Experiments were conducted on 146 nonlinear white male rats weighing 200-350 g. Partial critical intestinal ischemia was induced by thorough atraumatic strangulation of 5-6 cm jejunal loop with its mesentery for 90 rain. Global critical intestinal ischemia was made by atraumatic occlusion of the cranial mesenteric artery （CMA） for 90 rain also. Perftoran （PF, 0.8-1.0 mL per 100 g） in experimental groups or 0.9% sodium chloride in control groups was injected at 75 rain of ischemic period. Mean systemic arterial blood pressure （BPM） registration, intravital microscopy and morphological examination of ischemic intestine and its mesentery were performed in both groups. RESULTS： During 90 min of reperfusion, BPM progressively decreased to 27.3±7.4% after PF administration vs 38.6±8.0% in the control group of rats with partial intestinal ischemia （NS） and to 50.3±6.9% vs 53.1±5.8% in rats after global ischemia （NS）. During the reperfusion period, full restoration of microcirculation was never registered; parts with restored blood flow had leukocyte and erythrocyte stasis and intra-vascular clotting, a typical ＂non-reflow＂phenomenon. The reduction of mesenteric 50-400 μm feeding artery diameter was significantly less in the PF group than in the control group （24±5.5% vs 45.2±3.6%, P〈0.05） 5 min after partial intestinal ischemia. This decrease progressed but differences between groups minimized at the 90th min of reperfusion （41.5±4.2% and 50.3±2.8%, respectively）. In reperfusion of rat＇s intestine, a significant mucosal alteration was registered. Villous height decreased 2.5-3 times and the quantity of crypts decreased more than twice. In the group of rats administered PF, intestinal mucosal layer was protected from irreversible post-ischemic derangement during reperfusion. Saved cryptal epithelial cells were the source of regeneration of the epithelium, which began to cover renewing intestinal villi after 24 h of blood flow restoration. View of morphological alterations was more heterogeneous in CMA groups. CONCLUSION： Systemic administration of perftoran promotes earlier and more complete structural regeneration during reperfusion in rats after partial and global critical intestinal ischemia.

A surprising visual improvement following a prolonged 5-month retained subfoveal perfluorocarbon liquid

Dear Sir,I am Dr.Daniel Ting,from the Department of Ophthalmology,Singapore National Eye Centre,Singapore.I write to present a case of a surprising significant visual improvement following a prolonged 5-month retained subfoveal perfluorocarbon liquid.Retained perfluorocarbon liquid（PFCL）has been shown to cause decreased visual acuity,retinal pigment epithelial（RPE）toxicity,retinal degeneration and gravity deformation ,

Use of Perfluorocarbon Liquids in Complicated Retinal Detachments

We now have an additional tool to help in managing complicated retinal detachments. We look forward to the day when we can leave the liquid without having to remove it because of the possibility of ocular complications.

Ginsenoside modified lipid-coated perfluorocarbon nanodroplets: A novel approach to reduce complement protein adsorption and prolong in vivo circulation

Lipid-coated perfluorocarbon nanodroplets(lp-NDs)hold great promise in bio-medicine as vehicles for drug delivery,molecular imaging and vaccine agents.However,their clinical utility is restricted by limited targeted accumulation,attributed to the innate immune system(IIS),which acts as the initial defense mechanism in humans.This study aimed to optimize lp-ND formulations to mini-mize non-specific clearance by the IIS.Ginsenosides(Gs),the principal components of Panax ginseng,possessing complement inhibition ability,structural similarity to cholesterol,and comparable fat solubi-lity to phospholipids,were used as promising candidate IIS inhibitors.Two different types of ginsenoside-based Ip-NDs(Gs Ip-NDs)were created,and their efficacy in reducing IS recognition was examined.The Gs p-NDs were observed to inhibit the adsorption of C3 in the protein corona(PC)and the generation of SC5b-9.Adding Gs to Ip-NDs reduced complement adsorption and phagocytosis,resulting in a longer blood circulation time in vivo compared to lp-NDs that did not contain Gs.These results suggest that Gs can act as anti-complement and anti-phagocytosis adjuvants,potentially reducing non-specific clear-ance by the IS and improving lifespan.

Total liquid ventilation reduces oleic acid-induced lung injury in piglets

Background Pediatric patients are susceptible to lung injury that does not respond to traditional therapies. Total liquid ventilation has been developed as an alternative ventilatory strategy for severe lung injury. The aim of this study is to investigate the effect of total liquid ventilation on oleic acid （OA）-induced lung injury in piglets. Methods Twelve Chinese immature piglets were induced acute lung injury by OA. Twelve piglets were randomly treated with conventional gas ventilation （control group） or total liquid ventilation （study group） for 240 minutes. Samples for blood gas analysis were collected before, and at 60-minute intervals after OA-induced lung injury. The degree of lung injury was quantified by histologic examination. The inflammatory cells and the levels of IL-1β, IL-6, IL-10 and TNF-α in plasma, tissue and bronchoalveolar lavage were analyzed. Results Neutrophil and macrophage counts in bronchoalveolar lavage were significantly decreased in the study group （P〈0.05）. The total lung injury score was also reduced in the study group （P〈0.05）. The concentrations of IL-1β, IL-6, IL-10 and TNF-α in plasma, tissue and bronchoalveolar lavage were significantly reduced in the study group （P〈0.05）. Conclusions Total liquid ventilation reduces biochemical and histoloaic OA-induced luna iniurv in nialets.

Perfluorocarbon attenuates lipopolysaccharide-mediated inflammatory responses of alveolar epithelial cells in vitro

Background Toll-like receptor-4 （TLR-4） is integrally involved in lipopolysaccharide （LPS） signaling and has a requisite role in the activation of nuclear factor-κB （NF-κB）. The exact mechanisms that lend perfluorocarbon （PFC） liquids a cytoprotective effect have yet to be elucidated. Therefore we examined in an in vitro model the cytoprotective effect of PFC on LPS-stimulated alveolar epithelial cellls （AECs）. Methods AECs （A549 cells, human lung adenocarcinoma cell line） were divided into four groups： control, PFC, LPS and LPS ＋ PFC （coculture group） groups. Intercellular adhesion molecule-1 （ICAM-1） was detected by ELISA, tumor necrosis factor-g （TNF-a） and interleukin-8 （IL-8） were detected by radioimmunological methods. The expression of TLR-4 mRNA and protein was detected by real time PCR and Western blotting, respectively. The activation of NF-κB was detected by Western blotting （proteins of I-κBa and NF-κB p65）. Results ICAM-1, TNF-a and IL-8 were significantly increased in LPS-stimulated AECs groups. The expression of TLR-4 mRNA and protein in LPS-stimulated groups was markedly increased. Meanwhile, NF-κB was activated as indicated by the significant degradation of IKB-a and the significant release of NF-κB P65 and its subsequent translocation into the nucleus. There were no significant effects of PFC alone on any of the factors studied while the coculture group showed significant downregulation of the secretion of ICAM-1, TNF-a and IL-8, the expression of TLR-4 rn^NA and the activity of NF-κB. Conclusions Taken together, our results demonstrate that LPS can induce AEC-related inflammatory injury via the activation of TLR-4 and subsequent activation of NF-κB. PFC is able to protect AECs from LPS-induced inflammatory injury by blocking the initiation of the LPS signaling pathway, which is indicated by the significant decrease of TLR-4 expression and NF-κB activation.

Development of fluorinated polyplex nanoemulsions for improved small interfering RNA delivery and cancer therapy

We report the development of a small interfering RNA （siRNA） delivery vector based on cationic perfluorocarbon nanoemulsions. We have prepared perfluorodecalin （PFD） emulsions with a positive surface charge provided by a fluorinated poly（ethylenimine） （F-PEI）. The fluorinated emulsion （F-PEI@PFD） reduced cytotoxicity of F-PEI and demonstrated effective binding with siRNAs to form nanosized emulsion polyplexes. The prepared emulsion polyplexes enhanced cellular uptake and improved endosomal escape of the siRNA. In addition to increased reporter gene silencing in multiple cancer cell lines, when compared with control F-PEI and PEI polyplexes, the siR_NA emulsion polyplexes showed an excellent resistance to serum deactivation and maintained high activity, even in high-serum conditions. The F-PEI@PFD emulsion polyplexes carrying an siRNA to silence the expression of Bcl2 gene induced apoptosis and inhibited tumor growth in a melanoma mouse model in vivo and showed potential for in vivo ultrasound imaging. This study demonstrates the potential of F-PEI@PFD emulsions as a multifunctional theranostic nanoplatform for safe siRNA delivery, with integrated ultrasound imaging functionality.

A new method for concentration analysis of bacterial endotoxins in perfluorocarbon

This communication demonstrates the feasibility of the gel-clot method for the analysis of bacterial endotoxins in water extracts of perfluorocarbon which is a water insoluble liquid medical device. Perfluorocarbon （10 mL） was shaken with 10 mL water for 15 min at 2000 r/min and the endotoxin present was extracted to the aqueous phase without interference inhibition/enhancement of the product and the recovery of endotoxin added to perfluorocarbon was determined, A validation study confirmed that endotoxins presented in perfluorocarbon pass over into the aqueous phase at concentrations of 20, 10 and 5EU/mL with recoveries from 86.8% to 96.8%. Therefore, the gel-clot test is suitable for detecting bacterial endotoxins in perfluorocarbon which is a water insoluble medical device.

Facile Synthesis of Novel Perfluorocarbon-Modulated 4-Anilinoquinazoline Analogues

4-Anilinoquinazoline analogues stand out among many kinds of small molecules that inhibit the tyrosine kinase activities of epidermal growth factor receptor （EGFR）, thus serving as significant molecular targets for anticancer drug design. Herein, a series of novel perfluorocarbon （PFC） modulated 4-anilinoquinazolines were designed and prepared straightforwardly by nucleophilic substitution reaction of various anilinoquinazolines and PFC-derived methanesulfonate. In the presence of base, the reaction proceeded smoothly to afford a wide range of 4-anilino- quinazolines with different substituents on aniline moiety in good to high yields. Furthermore, the PFC-modified analogues of gefitinib and erlotinib were also obtained in 93% and 90% respectively, which may have potential for developing new inhibitors of the epidermal growth factor receptor （EGFR） tyrosine kinase and fluorinated contrast agents （CA） for 19F MRI.

Color-coded perfluorocarbon nanodroplets for multiplexed ultrasound and photoacoustic imaging

Laser-activated perfluorocarb on n anodroplets are an emerging class of phase-cha nge, dual-c ontrast age nts that can be utilized in ultraso und and photoacoustic imaging. Through the ability to differe ntiate subpopulations of nano droplets via laser activatio n at differe nt wavelengths of n ear-infrared light, optically-triggered color-coded perfluorocarb on nano droplets prese nt themselves as an attractive tool for multiplexed ultrasound and photoacoustic imaging. In particular, laser-activated droplets can be used to provide quantitative spatiotemporal information regarding distinct biological targets, allowing for their potential use in a wide range of diagnostic and therapeutic applications. In the work prese nted, laser-activated color-coded perfluorocarb on nan odroplets are syn thesized to selectively resp ond to laser irradiati on at corresp on ding wavele ngths. The dyn amic ultraso und and photoacoustic signals produced by laser-activated perfluorocarbon nano droplets are evaluated in situ prior to implementation in a murine model. In vivo, these particles are used to distinguish unique particle trafficking mechanisms and are show n to provide ultraso und and photoacoustic contrast for up to 72 hours within lymphatics. Overall, the con ducted studies show that laser-activated color-coded perfluorocarbo n nano droplets are a promising agent for multiplexed ultraso und and photoacoustic imaging.