Effect of vitamin A palmitate ophthalmic gel adjunctive therapy on tear film stability and inflammatory cytokines in patients with dry eye

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Ya-Yuan Lu

2018-06-01

Full Text Available AIM:To investigate the effect of sodium hyaluronate eye drops combined with vitamin A palmitate ophthalmic gel on levels of tear film stability and inflammatory cytokines in patients with dry eye. METHODS: A total of 100 patients with dry eye treated in our hospital from January 2015 to February 2017 were randomly divided into control group and observation group, 50 cases in each group. Patients in the control group were treated with sodium hyaluronate eye drops. Patients in the observation group were given vitamin A palmitate ophthalmic gel on the basis of the control group, and then the clinical efficacy, tear film stability and the level of inflammatory cytokines were detected in the two groups. RESULTS: After treatment, the levels of BUT and SⅠt in both groups increased significantly compared with that before treatment, and FL was significantly lower than that before treatment. The levels of BUT and SⅠt in the observation group after treatment were 11.24±0.22s and 11.4±0.17mm/5min respectively, which was high than that of control groups(PPPPCONCLUSION: Sodium hyaluronate eye drops combined with vitamin A palmitate ophthalmic gel can relieve the symptoms of patients with dry eye effectively, increase the stability of tear film, and reduce the levels of inflammatory factors in tears, which is reliable in clinical application.

Post-blink tear film dynamics in healthy and dry eyes during spontaneous blinking.

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Szczesna-Iskander, Dorota H

2018-01-01

The aim was to investigate the dynamics of post-blink tear film leveling in natural blinking conditions (NBC) for healthy subjects and those diagnosed with dry eye syndrome (DES) and to relate this phase to the tear film surface quality (TFSQ) before the following blink. The study included 19 healthy persons and 10 with dry eye, grouped according to symptoms and signs observed during examination. Lateral shearing interferometry was used to examine TFSQ. Post-blink tear film dynamics was modeled by an exponential function, characterized by the decay parameter b, and a constant, describing the level of the stabilized TFSQ. Pre-next-natural-blink TFSQ dynamics was modeled with a linear trend, described by a parameter A. The post-blink tear film dynamics reached its plateau at a significantly (P = 0.006) lower level in the normal tear film group than in the dry eye group. The median exponential decay parameter b was statistically significantly higher for the control group than for the DES group, P = 0.026. The parameter b calculated for each interblink interval was significantly correlated with the corresponding parameter A (Spearman's R = 0.35; P film fluorescein break-up time for each subject was also found (R = 0.41, P = 0.029). Significantly faster leveling of post-natural-blink tear film was observed in the group with DES than in healthy eyes. This dynamic was correlated with the pre-next-natural-blink TFSQ and tear film stability. The results of this pilot study support previous works that advocate the importance of polar lipids in the mechanism of tear film lipid spreading. Copyright © 2017 Elsevier Inc. All rights reserved.

Dynamic measurement of the corneal tear film with a Twyman-Green interferometer

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Micali, Jason D.; Greivenkamp, John E.; Primeau, Brian C.

2015-05-01

An interferometer for measuring dynamic properties of the in vivo tear film on the human cornea has been developed. The system is a near-infrared instantaneous phase-shifting Twyman-Green interferometer. The laser source is a 785 nm solid-state laser, and the system has been carefully designed and calibrated to ensure that the system operates at eye-safe levels. Measurements are made over a 6 mm diameter on the cornea. Successive frames of interferometric height measurements are combined to produce movies showing both the quantitative and qualitative changes in the topography of the tear film surface and structure. To date, measurement periods of up to 120 s at 28.6 frames per second have been obtained. Several human subjects have been examined using this system, demonstrating a surface height resolution of 25 nm and spatial resolution of 6 μm. Examples of features that have been observed in these preliminary studies of the tear film include postblink disruption, evolution, and stabilization of the tear film; tear film artifacts generated by blinking; tear film evaporation and breakup; and the propagation of foreign objects in the tear film. This paper discusses the interferometer design and presents results from in vivo measurements.

Interferometric characterization of tear film dynamics

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Primeau, Brian Christopher

The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. When a contact lens is on worn, the tear film covers the contact lens as it would a bare cornea, and is affected by the contact lens material properties. Tear film irregularity can cause both discomfort and vision quality degradation. Under normal conditions, the tear film is less than 10 microns thick and the thickness and topography change in the time between blinks. In order to both better understand the tear film, and to characterize how contact lenses affect tear film behavior, two interferometers were designed and built to separately measure tear film behavior in vitro and in vivo. An in vitro method of characterizing dynamic fluid layers applied to contact lenses mounted on mechanical substrates has been developed using a phase-shifting Twyman-Green interferometer. This interferometer continuously measures light reflected from the surface of the fluid layer, allowing precision analysis of the dynamic fluid layer. Movies showing this fluid layer behavior can be generated. The fluid behavior on the contact lens surface is measured, allowing quantitative analysis beyond what typical contact angle or visual inspection methods provide. The in vivo interferometer is a similar system, with additional modules included to provide capability for human testing. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or videokeratometry and provides better sensitivity and resolution than shearing interferometry methods.

Organization of lipids in the tear film: a molecular-level view.

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Alicja Wizert

Full Text Available Biophysical properties of the tear film lipid layer are studied at the molecular level employing coarse grain molecular dynamics (MD simulations with a realistic model of the human tear film. In this model, polar lipids are chosen to reflect the current knowledge on the lipidome of the tear film whereas typical Meibomian-origin lipids are included in the thick non-polar lipids subphase. Simulation conditions mimic those experienced by the real human tear film during blinks. Namely, thermodynamic equilibrium simulations at different lateral compressions are performed to model varying surface pressure, and the dynamics of the system during a blink is studied by non-equilibrium MD simulations. Polar lipids separate their non-polar counterparts from water by forming a monomolecular layer whereas the non-polar molecules establish a thick outermost lipid layer. Under lateral compression, the polar layer undulates and a sorting of polar lipids occurs. Moreover, formation of three-dimensional aggregates of polar lipids in both non-polar and water subphases is observed. We suggest that these three-dimensional structures are abundant under dynamic conditions caused by the action of eye lids and that they act as reservoirs of polar lipids, thus increasing stability of the tear film.

Transient Tear Film Dysfunction after Cataract Surgery in Diabetic Patients.

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Donghong Jiang

Full Text Available Diabetes mellitus is an increasingly common systemic disease. Many diabetic patients seek cataract surgery for a better visual acuity. Unlike in the general population, the influence of cataract surgery on tear film function in diabetic patients remains elusive. The aim of this study was to evaluate the tear function in diabetic and nondiabetic patients following cataract surgery.In this prospective, interventional case series, 174 diabetic patients without dry eye syndrome (DES and 474 age-matched nondiabetic patients as control who underwent phacoemulsification were enrolled at two different eye centers between January 2011 and January 2013. Patients were followed up at baseline and at 7 days, 1 month, and 3 months postoperatively. Ocular symptom scores (Ocular Surface Disease Index, OSDI and tear film function including tear film stability (tear film break-up time, TBUT, corneal epithelium integrity (corneal fluorescein staining, CFS, and tear secretion (Schirmer's I test, SIT were evaluated.In total, 83.9% of the diabetic patients (146 cases with 185 eyes and 89.0% of the nondiabetic patients (422 cases with 463 eyes completed all check-ups after the interventions (P = 0.095. The incidence of DES was 17.1% in the diabetic patients and 8.1% in the nondiabetic patients at 7 days after cataract surgery. In the diabetic patients, the incidence of DES remained 4.8% at 1 month postoperatively and decreased to zero at 3 months after surgery. No DES was diagnosed in nondiabetic patients at either the 1-month or 3-month follow-up. Compared with the baseline, the diabetic patients had worse symptom scores and lower TBUT values at 7 days and 1 month but not at 3 months postoperatively. In the nondiabetic patients, symptom scores and TBUT values had returned to preoperative levels at 1-month check-up. CFS scores and SIT values did not change significantly postoperatively in either group (P = 0.916 and P = 0.964, respectively.Diabetic patients undergoing

Tear secretion and tear stability of women on hormonal contraceptives

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Faustina Kemdinum Idu

2013-01-01

Conclusions: Injectable hormonal contraceptives had no significant effects on tear secretion and tear stability of healthy women of childbearing age. Further studies may be required to determine the effects of hormonal contraceptives on tear volume and stability of women with dry eyes.

Tear film measurement by optical reflectometry technique

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Lu, Hui; Wang, Michael R.; Wang, Jianhua; Shen, Meixiao

2014-01-01

Abstract. Evaluation of tear film is performed by an optical reflectometer system with alignment guided by a galvanometer scanner. The reflectometer system utilizes optical fibers to deliver illumination light to the tear film and collect the film reflectance as a function of wavelength. Film thickness is determined by best fitting the reflectance-wavelength curve. The spectral reflectance acquisition time is 15 ms, fast enough for detecting film thickness changes. Fast beam alignment of 1 s is achieved by the galvanometer scanner. The reflectometer was first used to evaluate artificial tear film on a model eye with and without a contact lens. The film thickness and thinning rate have been successfully quantified with the minimum measured thickness of about 0.3 μm. Tear films in human eyes, with and without a contact lens, have also been evaluated. A high-contrast spectral reflectance signal from the precontact lens tear film is clearly observed, and the thinning dynamics have been easily recorded from 3.69 to 1.31 μm with lipid layer thickness variation in the range of 41 to 67 nm. The accuracy of the measurement is better than ±0.58% of the film thickness at an estimated tear film refractive index error of ±0.001. The fiber-based reflectometer system is compact and easy to handle. PMID:24500519

Effectiveness of Combined Tear Film Therapy in Patients with Evaporative Dry Eye with Short Tear Film Breakup Time.

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Kim, Yung Hui; Kang, Yeon Soo; Lee, Hyo Seok; Choi, Won; You, In Cheon; Yoon, Kyung Chul

2017-10-01

The aim of this study was to evaluate the effectiveness of combined tear film therapy targeted to aqueous, mucin, and lipid layers in patients with refractory evaporative dry eye (EDE) with short tear film breakup time (TBUT). The patients who had EDE with short TBUT and severe symptoms refractory to artificial tears were treated with hyaluronic acid (HA) 0.15% and diquafosol tetrasodium (DQS) 3% (Group 1), HA and carbomer-based lipid-containing eyedrops (Liposic EDO Gel, LPO) (Group 2), or HA, DQS, and LPO (Group 3). Ocular Surface Disease Index (OSDI) score, visual analog scale (VAS) symptom score, TBUT, Schirmer score, and corneal and conjunctival staining scores were evaluated, and noninvasive tear film breakup time (NIBUT) and tear meniscus height were measured using Keratograph ® 5 M before and 1 and 3 months after treatment. OSDI scores, VAS scores, TBUT, and NIBUT were improved at 1 and 3 months after treatment in all groups (all P film layers was most effective in improving ocular symptoms and tear film quality.

Linear stability of tearing modes

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Cowley, S.C.; Kulsrud, R.M.; Hahm, T.S.

1986-05-01

This paper examines the stability of tearing modes in a sheared slab when the width of the tearing layer is much smaller than the ion Larmor radius. The ion response is nonlocal, and the quasineutrality retains its full integal form. An expansion procedure is introduced to solve the quasineutrality equation in powers of the width of the tearing layer over the ion Larmor radius. The expansion procedure is applied to the collisionless and semi-collisional tearing modes. The first order terms in the expansion we find to be strongly stabilizing. The physics of the mode and of the stabilization is discussed. Tearing modes are observed in experiments even though the slab theory predicts stability. It is proposed that these modes grow from an equilibrium with islands at the rational surfaces. If the equilibrium islands are wider than the ion Larmor radius, the mode is unstable when Δ' is positive

Tear Film Break-Up Time: Comparison between Patients using Psychiatric Drugs and Healthy Individuals

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Parvin Dibajnia

2014-09-01

Full Text Available Background: Ocular dryness is a well-recognized adverse side effect of many medications. The purpose of this study was to compare tear film stability between psychiatric patients that use lithium carbonate or carbamazepine and normal cases. Materials and Methods: Tear film break up time test was performed in three groups, 30 patients using lithium carbonate, 30 patients using carbamazepine and 30 normal cases. Values of the TBUTs were compared among groups by the independent t-test. Results: Differences between both of patients and control groups were significant (p<0.0001. Conclusion: The results show that these drugs contribute to decrease of tear film break up time.

Tear-Film Evaporation Rate from Simultaneous Ocular-Surface Temperature and Tear-Breakup Area.

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Dursch, Thomas J; Li, Wing; Taraz, Baseem; Lin, Meng C; Radke, Clayton J

2018-01-01

A corneal heat-transfer model is presented to quantify simultaneous measurements of fluorescein tear-breakup area (TBA) and ocular-surface temperature (OST). By accounting for disruption of the tear-film lipid layer (TFLL), we report evaporation rates through lipid-covered tear. The modified heat-transfer model provides new insights into evaporative dry eye. A quantitative analysis is presented to assess human aqueous tear evaporation rate (TER) through intact TFLLs from simultaneous in vivo measurement of time-dependent infrared OST and fluorescein TBA. We interpret simultaneous OST and TBA measurements using an extended heat-transfer model. We hypothesize that TBAs are ineffectively insulated by the TFLL and therefore exhibit higher TER than does that for a well-insulting TFLL-covered tear. As time proceeds, TBAs increase in number and size, thereby increasing the cornea area-averaged TER and decreasing OST. Tear-breakup areas were assessed from image analysis of fluorescein tear-film-breakup video recordings and are included in the heat-transfer description of OST. Model-predicted OSTs agree well with clinical experiments. Percent reductions in TER of lipid-covered tear range from 50 to 95% of that for pure water, in good agreement with literature. The physical picture of noninsulating or ruptured TFLL spots followed by enhanced evaporation from underlying cooler tear-film ruptures is consistent with the evaporative-driven mechanism for local tear rupture. A quantitative analysis is presented of in vivo TER from simultaneous clinical measurement of transient OST and TBA. The new heat-transfer model accounts for increased TER through expanding TBAs. Tear evaporation rate varies strongly across the cornea because lipid is effectively missing over tear-rupture troughs. The result is local faster evaporation compared with nonruptured, thick lipid-covered tear. Evaporative-driven tear-film ruptures deepen to a thickness where fluorescein quenching commences and local

Effect of lipid-based dry eye supplements on the tear film in wearers of eye cosmetics.

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Wang, Michael T M; Cho, Irene Sung Hee; Jung, Soo Hee; Craig, Jennifer P

2017-08-01

To compare the effects on tear film parameters and contamination in cosmetic eyeliner wearers, after single application of two lipid-based dry eye treatments: a lipid-containing lubricant eye drop and a phospholipid liposomal spray. Fifty participants were enrolled in a prospective, randomised, paired-eye, investigator-masked trial. Pencil eyeliner (Body Shop ® Crayon Eye Definer) was applied to the upper eyelid periocular skin of both eyes, anterior to the lash line. Baseline tear film quality was assessed fifteen minutes after eyeliner application. A lubricant drop (Systane ® Balance) was then applied to one eye (randomised), and liposomal spray (Tears Again ® ) to the contralateral eye. Tear film contamination, lipid layer grade, non-invasive tear film break-up time and tear evaporation rate were evaluated fifteen minutes post-treatment and compared to pre-treatment values. Pre-treatment measurements did not differ between eyes assigned to lubricant drop and liposomal spray. Tear film contamination was observed in a greater proportion of eyes following both treatments (both p0.05). Changes in tear film parameters did not differ between treatments (all p>0.05). Both the lipid-containing lubricant eye drop and phospholipid liposomal spray result in clinically apparent tear film contamination in eyeliner cosmetic wearers. Although both treatments effected an increase in lipid layer thickness, neither displayed clinical efficacy in improving tear film stability. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Duplex Tear Film Evaporation Analysis.

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Stapf, M R; Braun, R J; King-Smith, P E

2017-12-01

Tear film thinning, hyperosmolarity, and breakup can cause irritation and damage to the human eye, and these form an area of active investigation for dry eye syndrome research. Recent research demonstrates that deficiencies in the lipid layer may cause locally increased evaporation, inducing conditions for breakup. In this paper, we explore the conditions for tear film breakup by considering a model for tear film dynamics with two mobile fluid layers, the aqueous and lipid layers. In addition, we include the effects of osmosis, evaporation as modified by the lipid, and the polar portion of the lipid layer. We solve the system numerically for reasonable parameter values and initial conditions and analyze how shifts in these cause changes to the system's dynamics.

Effect of rb-bFGF eye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery

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Jing Chen

2017-10-01

Full Text Available AIM: To compare and analyze the effect of recombinant bovine basic fibroblast growth factor(bFGFeye drops and hydroxyl indican eye drops on the tear film stability and dry eye symptoms after age-related cataract surgery. METHODS: A total of 115 patients(115 affected eyeswith dry eyes after age-related cataract surgery were divided into the bFGF group, the hydroxyl indican group and the blank control group by the random number table method. The blank control group was only given routine anti-inflammatory treatment, and on the basis, the bFGF group and the hydroxyl indican group were treated with bFGF eye drops and hydroxyl indican eye drops respectively. The clinical efficacy, adverse reactions, changes in scores of dry eye symptoms, Schirmer test(SⅠt, tear film break-up time(BUTand corneal fluorescein staining(CFSscores at different time points were compared among the three groups. RESULTS: The total markedly effective rates in the bFGF group(89.5%was higher than that in the hydroxyl indican group(70.3%or the blank control group(47.5%(PPPCONCLUSION: The tear film is unstable in early stage after age-related cataract surgery, and there are dry eye symptoms. The intervention with bFGF eye drops and hydroxyl indican eye drops can effectively restore the tear film stability and significantly relieve dry eye symptoms, and the effect of bFGF eye drops is more significant.

Consistency analysis of Keratograph and traditional methods to evaluate tear film function

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Pei-Yang Shen

2015-05-01

Full Text Available AIM: To investigate repeatability and accuracy of a latest Keratograph for evaluating the tear film stability and to compare its measurements with that of traditional examination methods. METHODS: The results of noninvasive tear film break-up time(NI-BUTincluding the first tear film break-up time(BUT-fand the average tear film break-up time(BUT-avewere measured by Keratograph. The repeatability of the measurements was evaluated by coefficient of variation(CVand intraclass correlation coefficient(ICC. Wilcoxon Signed-Rank test was used to compare NI-BUT with fluorescein tear film break-up time(FBUTto confirm the correlation between NI-BUT and FBUT, Schirmer I test values. Bland-Altman analysis was used to evaluate consistency. RESULTS: The study recruited 48 subjects(48 eyes(mean age 38.7±15.2 years. The CV and ICC of BUT-f were respectively 12.6% and 0.95, those of BUT-ave were 9.8% and 0.96. The value of BUT-f was lower than that of FBUT. The difference had statistical significance(6.16±2.46s vs 7.46±1.92s, PPCONCLUSION: Keratograph can provide NI-BUT data that has a better repeatability and reliability, which has great application prospects in diagnosis and treatment of dry eye and refractive corneal surgery.

Effects of tear film dynamics on quality of vision.

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Koh, Shizuka; Tung, Cynthia I; Inoue, Yasushi; Jhanji, Vishal

2018-06-15

The precorneal tear film is maintained by blinking and exhibits different phases in the tear cycle. The tear film serves as the most anterior surface of the eye and plays an important role as a first refractive component of the eye. Alterations in tear film dynamics may cause both vision-related and ocular surface-related symptoms. Although the optical quality associated with the tear film dynamics previously received little attention, objective measurements of optical quality using wavefront sensors have enabled us to quantify optical aberrations induced by the tear film. This has provided an objective method for assessing reduced optical quality in dry eye; thus, visual disturbances were included in the definition of dry eye disease in the 2007 Dry Eye Workshop report. In addition, sequential measurements of wavefront aberrations have provided us with valuable insights into the dynamic optical changes associated with tear film dynamics. This review will focus on the current knowledge of the mechanisms of wavefront variations that are caused by different aspects of tear film dynamics: specifically, quality, quantity and properties of the tear film, demonstrating the respective effects of dry eye, epiphora and instillation of eye drops on the quality of vision. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Adsorption of human tear lipocalin to human meibomian lipid films.

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Millar, Thomas J; Mudgil, Poonam; Butovich, Igor A; Palaniappan, Chendur K

2009-01-01

Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (Pi-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37 degrees C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in Pi-T profiles and the microscopic appearance of the films. It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film.

Adsorption of Human Tear Lipocalin to Human Meibomian Lipid Films

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Millar, Thomas J.; Mudgil, Poonam; Butovich, Igor A.; Palaniappan, Chendur K.

2009-01-01

Purpose Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Methods Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (∏-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. Results The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37°C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in ∏-T profiles and the microscopic appearance of the films. Conclusions It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film. PMID:18757516

On tear film breakup (TBU): dynamics and imaging.

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Braun, Richard J; Driscoll, Tobin A; Begley, Carolyn G; King-Smith, P Ewen; Siddique, Javed I

2018-06-13

We report the results of some recent experiments to visualize tear film dynamics. We then study a mathematical model for tear film thinning and tear film breakup (TBU), a term from the ocular surface literature. The thinning is driven by an imposed tear film thinning rate which is input from in vivo measurements. Solutes representing osmolarity and fluorescein are included in the model. Osmolarity causes osmosis from the model ocular surface, and the fluorescein is used to compute the intensity corresponding closely to in vivo observations. The imposed thinning can be either one-dimensional or axisymmetric, leading to streaks or spots of TBU, respectively. For a spatially-uniform (flat) film, osmosis would cease thinning and balance mass lost due to evaporation; for these space-dependent evaporation profiles TBU does occur because osmolarity diffuses out of the TBU into the surrounding tear film, in agreement with previous results. The intensity pattern predicted based on the fluorescein concentration is compared with the computed thickness profiles; this comparison is important for interpreting in vivo observations. The non-dimensionalization introduced leads to insight about the relative importance of the competing processes; it leads to a classification of large vs small TBU regions in which different physical effects are dominant. Many regions of TBU may be considered small, revealing that the flow inside the film has an appreciable influence on fluorescence imaging of the tear film.

Analysis of the correlation between tear film changes of allergic conjunctivitis and dry eye

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Yong Li

2014-07-01

Full Text Available AIM: To analyze the correlation between tear film changes of allergic conjunctivitis and dry eye, then provide clinical references for better treatment. METHODS: Fifty patients with allergic conjunctivitis were taken as the observation group, the control group was selected based on 1:1 case control theory, and we chose 50 health volunteers without ocular surface diseases, xerophthalmia and systematic diseases randomly, then fluorescein(FLstaining, break-up time(BUT, Schirner I test(SⅠt, tear meniscus high(TMHand slit-lamp examinations were performed in the two groups. RESULTS: In the observation group, FL, BUT, SIt, TMH of right eyes and left eyes were statistically significant correlated(PPPCONCLUSION: Due to inflammatory mediators participation, allergic conjunctivitis could lead to the stability changes of tear film which cause in dry eye. The stability changes of allergic conjunctivitis correlate to the damage degree of epithelium.

Impact of environmental adaptation on tear film assessments.

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Fagehi, R

2018-03-01

The purpose of this study was to investigate the effect of ocular environmental adaptation on clinical tear film assessment. Thirty subjects (male, mean age 23±2.5) participated in this study. A number of clinical tear film tests were applied, including: fluorescein tear break-up time (FTBUT), Schirmer test and tear prism height test (TPH). The tear physiology of each subject was evaluated twice, once immediately when they arrived from the external environment, and then after 30minutes adaptation in the exam room environment. The mean values were: Schirmer test A (22.1±2.99), Schirmer test B (24.2±2.63), FTBUT A (8.00±1.94), FTBUT B (9.13±2.04), TPH A (0.179±0.026) and TPH B* (0.187±0.023). Statistical testing using Wilcoxon-signed rank test showed a significant difference between the Schirmer test results measured at the different times (P=0.008). Also, the FTBUT and tear prism height test results showed significant differences between the two evaluation times, (P=0.001, 0.011, respectively) (A: tear assessed when the subject comes from the outside environment, B: tear film assessed after 30min adaptation in the clinical environment). This study showed a significant difference between the tear film test results evaluated when the subjects were assessed immediately from the outside environment and after an adaptation time in the clinic environment. Practitioners must consider the effect of differences between external and clinical environment adaptation on clinical tear film physiology. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

[The correlations between corneal sensation, tear meniscus volume, and tear film osmolarity after femtosecond laser-assisted LASIK].

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Zhang, Luyan; Sun, Xiyu; Yu, Ye; Xiong, Yan; Cui, Yuxin; Wang, Qinmei; Hu, Liang

2016-01-01

To investigate the correlations between corneal sensation, tear meniscus volume, and tear film osmolarity after femtosecond laser-assisted LASIK (FS-LASIK) surgery. In this prospective clinical study, 31 patients undergoing FS-LASIK for myopia were recruited. The upper and lower tear meniscus volumes (UTMV and LTMV) were measured by customized anterior segment optical coherence tomography, tear film osmolarity was measured by a TearLab Osmolarity test device, central corneal sensation was measured by a Cochet-Bonner esthesiometer preoperatively, at 1 week, 1 and 3 months postoperatively. Repeated measures analysis of variance was used to evaluate whether the tear film osmolarity, tear meniscus volume, and corneal sensation were changed after surgery. The correlations between these variables were analyzed by the Pearson correlation analysis. The tear film osmolarity was (310.03 ± 16.48) mOsms/L preoperatively, (323.51 ± 15.92) mOsms/L at 1 week, (319.93 ± 14.27) mOsms/L at 1 month, and (314.97±12.91) mOsms/L at 3 months. The UTMV was (0.42±0.15), (0.25± 0.09), (0.30±0.11), and (0.35±0.09) μL, respectively; the LTMV was (0.60±0.21),(0.37±0.08), (0.44± 0.14), and (0.52±0.17) μL, respectively. The tear film osmolarity was significantly higher at 1 week and 1 month postoperatively compared with the baseline (P=0.001, 0.004), and reduced to the preoperative level at 3 months (P=0.573). The UTMV, LTMV, and corneal sensation values presented significant decreases at all postoperative time points (all Psensation at 1 week after surgery (r=0.356,P=0.005). There were significant correlations between the preoperative LTMV and corneal sensation at 1 week, 1 and 3 months (respectively, r=0.422, 0.366, 0.352;P=0.001, 0.004, 0.006). No significant correlations were found between the tear film osmolarity, tear meniscus volume, and corneal sensation after surgery (all P>0.05). The tear film osmolarity, tear meniscus volume, and corneal sensation became aggravated due

Goldmann tonometry tear film error and partial correction with a shaped applanation surface.

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McCafferty, Sean J; Enikov, Eniko T; Schwiegerling, Jim; Ashley, Sean M

2018-01-01

The aim of the study was to quantify the isolated tear film adhesion error in a Goldmann applanation tonometer (GAT) prism and in a correcting applanation tonometry surface (CATS) prism. The separation force of a tonometer prism adhered by a tear film to a simulated cornea was measured to quantify an isolated tear film adhesion force. Acrylic hemispheres (7.8 mm radius) used as corneas were lathed over the apical 3.06 mm diameter to simulate full applanation contact with the prism surface for both GAT and CATS prisms. Tear film separation measurements were completed with both an artificial tear and fluorescein solutions as a fluid bridge. The applanation mire thicknesses were measured and correlated with the tear film separation measurements. Human cadaver eyes were used to validate simulated cornea tear film separation measurement differences between the GAT and CATS prisms. The CATS prism tear film adhesion error (2.74±0.21 mmHg) was significantly less than the GAT prism (4.57±0.18 mmHg, p film adhesion error was independent of applanation mire thickness ( R 2 =0.09, p =0.04). Fluorescein produces more tear film error than artificial tears (+0.51±0.04 mmHg; p film adhesion error (1.40±0.51 mmHg) was significantly less than that of the GAT prism (3.30±0.38 mmHg; p =0.002). Measured GAT tear film adhesion error is more than previously predicted. A CATS prism significantly reduced tear film adhesion error bŷ41%. Fluorescein solution increases the tear film adhesion compared to artificial tears, while mire thickness has a negligible effect.

Interferometer for measuring the dynamic surface topography of a human tear film

Science.gov (United States)

Primeau, Brian C.; Greivenkamp, John E.

2012-03-01

The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. Following a blink, the tear film quickly smoothes and starts to become irregular after 10 seconds. This irregularity can affect comfort and vision quality. An in vivo method of characterizing dynamic tear films has been designed based upon a near-infrared phase-shifting interferometer. This interferometer continuously measures light reflected from the tear film, allowing sub-micron analysis of the dynamic surface topography. Movies showing the tear film behavior can be generated along with quantitative metrics describing changes in the tear film surface. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or corneal topography and provides better sensitivity and resolution than shearing interferometry methods. The interferometer design is capable of identifying features in the tear film much less than a micron in height with a spatial resolution of about ten microns over a 6 mm diameter. This paper presents the design of the tear film interferometer along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry.

Effect of three different liposomal eye sprays on ocular comfort and tear film.

Science.gov (United States)

Pult, Heiko; Gill, Felicity; Riede-Pult, Britta H

2012-10-01

To evaluate the effect of three different liposomal eye sprays on ocular comfort and tear film stability. OptrexActiMist (AM, Optima-Pharma, Germany) was applied onto one, randomly selected eye of 80 subjects (female=49; mean age=49 years±18.6 SD) in a multi-centred, double-masked study. DryEyesMist (DEM, Boots) or TearMist (TM, Tesco) was applied onto the contralateral eye in randomized order. Over-all symptoms were investigated using the Ocular Surface Disease Index (OSDI). Ocular comfort (visual-analogue scale 0-100 [100=perfect]) and non-invasive tear film stability (NIBUT) of each eye was evaluated before application (randomized order) and were again measured 10 min after application. Effects of products on ocular comfort and NIBUT were calculated as "factor" (=after-treatment/before-treatment). Differences between measurements were analysed by ANOVA repeated measurements and differences between groups by the dependent t-test (or the non-parametric equivalent). OSDI-scores (mean=8.1±9.0 SD), comfort (65±24) and NIBUT (12 s±12.3) were statistically similar between centres (p>0.400). Comfort and NIBUT were not different (p>0.14) between product groups before application. Comfort and NIBUT improved significantly after application of AM (p<0.001) but worsened with the comparing products (p<0.058). Comfort improved by a mean factor of 1.5 (±0.82 SD) after application of AM but decreased after application of the comparing products (DEM: 0.9±0.33; TM: 0.9±0.34). Both factors were significantly better in AM (p<0.027). The original liposomal eye-spray 'OptrexActiMist' significantly improved ocular comfort and tear film stability while 'TearMist' or 'DryEyesMist' worsened both criteria. The latter two products may not be clinically effective in the treatment of dry eye. Copyright © 2012 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Meniscal Tear Film Fluid Dynamics Near Marx’s Line

KAUST Repository

Zubkov, V. S.

2013-07-03

Extensive studies have explored the dynamics of the ocular surface fluid, though theoretical investigations are typically limited to the use of the lubrication approximation, which is not guaranteed to be uniformly valid a-priori throughout the tear meniscus. However, resolving tear film behaviour within the meniscus and especially its apices is required to characterise the flow dynamics where the tear film is especially thin, and thus most susceptible to evaporatively induced hyperosmolarity and subsequent epithelial damage. Hence, we have explored the accuracy of the standard lubrication approximation for the tear film by explicit comparisons with the 2D Navier-Stokes model, considering both stationary and moving eyelids. Our results demonstrate that the lubrication model is qualitatively accurate except in the vicinity of the eyelids. In particular, and in contrast to lubrication theory, the solution of the full Navier-Stokes equations predict a distinct absence of fluid flow, and thus convective mixing in the region adjacent to the tear film contact line. These observations not only support emergent hypotheses concerning the formation of Marx\\'s line, a region of epithelial cell staining adjacent to the contact line on the eyelid, but also enhance our understanding of the pathophysiological consequences of the flow profile near the tear film contact line. © 2013 Society for Mathematical Biology.

Tear film lipid layer: A molecular level view

Czech Academy of Sciences Publication Activity Database

Cwiklik, Lukasz

2016-01-01

Roč. 1858, č. 10 (2016), s. 2421-2430 ISSN 0005-2736 R&D Projects: GA ČR GA15-14292S Institutional support: RVO:61388955 Keywords : tear film * tear film lipid layer * molecular dynamics simulations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.498, year: 2016

Tear film proteome in age-related macular degeneration.

Science.gov (United States)

Winiarczyk, Mateusz; Kaarniranta, Kai; Winiarczyk, Stanisław; Adaszek, Łukasz; Winiarczyk, Dagmara; Mackiewicz, Jerzy

2018-06-01

Age-related macular degeneration (AMD) is the main reason for blindness in elderly people in the developed countries. Current screening protocols have limitations in detecting the early signs of retinal degeneration. Therefore, it would be desirable to find novel biomarkers for early detection of AMD. Development of novel biomarkers would help in the prevention, diagnostics, and treatment of AMD. Proteomic analysis of tear film has shown promise in this research area. If an optimal set of biomarkers could be obtained from accessible body fluids, it would represent a reliable way to monitor disease progression and response to novel therapies. Tear films were collected on Schirmer strips from a total of 22 patients (8 with wet AMD, 6 with dry AMD, and 8 control individuals). 2D electrophoresis was used to separate tear film proteins prior to their identification with matrix-assisted laser desorption/ionization time of flight spectrometer (MALDI-TOF/TOF) and matching with functional databases. A total of 342 proteins were identified. Most of them were previously described in various proteomic studies concerning AMD. Shootin-1, histatin-3, fidgetin-like protein 1, SRC kinase signaling inhibitor, Graves disease carrier protein, actin cytoplasmic 1, prolactin-inducible protein 1, and protein S100-A7A were upregulated in the tear film samples isolated from AMD patients and were not previously linked with this disease in any proteomic analysis. The upregulated proteins supplement our current knowledge of AMD pathogenesis, providing evidence that certain specific proteins are expressed into the tear film in AMD. As far we are aware, this is the first study to have undertaken a comprehensive in-depth analysis of the human tear film proteome in AMD patients.

Meniscal Tear Film Fluid Dynamics Near Marx’s Line

KAUST Repository

Zubkov, V. S.; Breward, C. J. W.; Gaffney, E. A.

2013-01-01

meniscus. However, resolving tear film behaviour within the meniscus and especially its apices is required to characterise the flow dynamics where the tear film is especially thin, and thus most susceptible to evaporatively induced hyperosmolarity

Goldmann tonometry tear film error and partial correction with a shaped applanation surface

Directory of Open Access Journals (Sweden)

McCafferty SJ

2018-01-01

Full Text Available Sean J McCafferty,1–4 Eniko T Enikov,5 Jim Schwiegerling,2,3 Sean M Ashley1,3 1Intuor Technologies, 2Department of Ophthalmology, University of Arizona College of Medicine, 3University of Arizona College of Optical Science, 4Arizona Eye Consultants, 5Department of Mechanical and Aerospace, University of Arizona College of Engineering, Tucson, AZ, USA Purpose: The aim of the study was to quantify the isolated tear film adhesion error in a Goldmann applanation tonometer (GAT prism and in a correcting applanation tonometry surface (CATS prism.Methods: The separation force of a tonometer prism adhered by a tear film to a simulated cornea was measured to quantify an isolated tear film adhesion force. Acrylic hemispheres (7.8 mm radius used as corneas were lathed over the apical 3.06 mm diameter to simulate full applanation contact with the prism surface for both GAT and CATS prisms. Tear film separation measurements were completed with both an artificial tear and fluorescein solutions as a fluid bridge. The applanation mire thicknesses were measured and correlated with the tear film separation measurements. Human cadaver eyes were used to validate simulated cornea tear film separation measurement differences between the GAT and CATS prisms.Results: The CATS prism tear film adhesion error (2.74±0.21 mmHg was significantly less than the GAT prism (4.57±0.18 mmHg, p<0.001. Tear film adhesion error was independent of applanation mire thickness (R2=0.09, p=0.04. Fluorescein produces more tear film error than artificial tears (+0.51±0.04 mmHg; p<0.001. Cadaver eye validation indicated the CATS prism’s tear film adhesion error (1.40±0.51 mmHg was significantly less than that of the GAT prism (3.30±0.38 mmHg; p=0.002.Conclusion: Measured GAT tear film adhesion error is more than previously predicted. A CATS prism significantly reduced tear film adhesion error by ~41%. Fluorescein solution increases the tear film adhesion compared to

Effect of rb-bFGF eye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery

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Yu Ling

2018-01-01

Full Text Available AIM: To investigate the effect of recombinant bovine basic fibroblast growth factor(rb-bFGFeye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery. METHODS: Totally 80 patients with 80 affected eyes undergoing age-related cataract surgery in our hospital from January 2015 to October 2016 were selected as study subjects, and they were randomly divided into control group and experimental group with 40 patients(40 affected eyesin each group. The two groups were treated with hydroxyl indican eye drops and rb-bFGF eye drops, respectively. The clinical curative effect, inflammation related factors \\〖interleukin 6(IL-6, tumor necrosis factor α(TNF-α\\〗, Schirmer test(SⅠt, break-up time(BUTof tear film, corneal sodium fluorescein staining(FLand scores of dry eye symptoms in the two groups were observed. RESULTS: The total treatment effective rate of experimental group after treatment was significantly higher than that of the control group(90.0% vs 72.5%; χ2=4.021, PP>0.05. After treatment, IL-6, TNF-α, SⅠt, FL score and scores of dry eye symptoms in two groups significantly decreased while BUT significantly increased(PPCONCLUSION: In the treatment of patients after age-related cataract after surgery, rb-bFGF eye drops has more advantages over hydroxyl indican eye drops in regulating the expression of inflammatory factors, improving the tear film stability and relieving dry eye symptoms.

Surface Chemistry Interactions of Cationorm with Films by Human Meibum and Tear Film Compounds

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Georgi As. Georgiev

2017-07-01

Full Text Available Cationorm® (CN cationic nanoemulsion was demonstrated to enhance tear film (TF stability in vivo possibly via effects on tear film lipid layer (TFLL. Therefore the interactions of CN with human meibum (MGS and TFLL in vitro and in vivo deserve special study. MGS and CN were spread at the air/water interface of a Langmuir surface balance to ensure a range of MGS/CN oil phase ratios: 20/1, 10/1, 5/1, 3/1, 2/1 and 1/1. The films capability to reorganize during dynamic area changes was evaluated via the surface pressure-area compression isotherms and step/relaxation dilatational rheology studies. Films structure was monitored with Brewster angle microscopy. CN/TFLL interactions at the ocular surface were monitored with non-contact specular microscopy. The in vitro studies of MGS/CN layers showed that (i CN inclusion (at fixed MGS content increased film elasticity and thickness and that (ii CN can compensate for moderate meibum deficiency in MGS/CN films. In vivo CN mixed with TFLL in a manner similar to CN/MGS interactions in vitro, and resulted in enhanced thickness of TFLL. In vitro and in vivo data complement each other and facilitated the study of the composition-structure-function relationship that determines the impact of cationic nanoemulsions on TF.

The Effect of Polar Lipids on Tear Film Dynamics

KAUST Repository

Aydemir, E.

2010-06-17

In this paper, we present a mathematical model describing the effect of polar lipids, excreted by glands in the eyelid and present on the surface of the tear film, on the evolution of a pre-corneal tear film. We aim to explain the interesting experimentally observed phenomenon that the tear film continues to move upward even after the upper eyelid has become stationary. The polar lipid is an insoluble surface species that locally alters the surface tension of the tear film. In the lubrication limit, the model reduces to two coupled non-linear partial differential equations for the film thickness and the concentration of lipid. We solve the system numerically and observe that increasing the concentration of the lipid increases the flow of liquid up the eye. We further exploit the size of the parameters in the problem to explain the initial evolution of the system. © 2010 Society for Mathematical Biology.

The Effect of Polar Lipids on Tear Film Dynamics

KAUST Repository

Aydemir, E.; Breward, C. J. W.; Witelski, T. P.

2010-01-01

In this paper, we present a mathematical model describing the effect of polar lipids, excreted by glands in the eyelid and present on the surface of the tear film, on the evolution of a pre-corneal tear film. We aim to explain the interesting

Corneal sensitivity, ocular surface health and tear film stability after punctal plug therapy of aqueous deficient dry eye

Directory of Open Access Journals (Sweden)

Azza Mohamed Ahmed Said

2016-11-01

Full Text Available AIM: To evaluate the effect of punctal occlusion using thermosensitive (smart plug versus silicone plug for management of aqueous deficient dry eye on corneal sensitivity, ocular surface health and tear film stability. METHODS: A comparative prospective interventional case study included 45 patients with bilateral severe form of aqueous deficient dry eye. In each patient, the smart plug was inserted in the lower punctum of the right eye which was considered as study group 1 and silicone plug was inserted in the lower punctum of the left eye of the same patient which was considered as study group 2. All patients were subjected to careful history taking and questionnaire for subjective assessment of severity of symptoms. Corneal sensitivity, corneal fluorescein, rose bengal staining, Schirmer’s I test, tear film break up time and conjunctival impression cytology were performed pre and 1, 3 and 6mo post plug insertion. RESULTS: A statistically significant improvement in subjective and objective manifestations occurred following treatment with both types of plugs (P<0.01. The thermosensitive plug caused significant overall improvement, decrease in frequency of application of tear substitutes and improvement of conjunctival impression cytology parameters in the inserted side (P<0.01. Canaliculitis was reported in two eyes (4.4% following punctal occlusion using thermosensitive plug (study group 1. Spontaneous plug loss occurred in 21 eyes (46.6% in the silicone plug group (study group 2. CONCLUSION: Improvement of subjective and objective manifestations of aqueous deficient dry eye occurs following punctal plug occlusion. Thermosensitive plug has good patient's compliance with fewer complications and lower rates of loss compared to the silicone plug.

Cytokine biomarkers in tear film for primary open-angle glaucoma

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Gupta D

2017-02-01

Full Text Available Divakar Gupta,1,* Joanne C Wen,2,* Janet L Huebner,3 Sandra Stinnett,1 Virginia B Kraus,3,4 Henry C Tseng,1 Molly Walsh1 1Department of Ophthalmology, Duke University Medical Center, Durham, NC, 2Department of Ophthalmology, University of Washington, Seattle, WA, 3Duke Molecular Physiology Institute, 4Division of Rheumatology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA *These authors contributed equally to this work Purpose: To determine the utility of tear film cytokines as biomarkers for early primary open-angle glaucoma (POAG. Methods: Patients without POAG and eye drop-naïve patients with newly diagnosed POAG were recruited from an academic hospital-based glaucoma practice. Tear films of recruited patients were obtained and analyzed using a multiplex, high-sensitivity electrochemiluminescent enzyme-linked immunosorbent assay for proinflammatory cytokines (IFNγ, IL-10, IL-12p70, IL-13, IL-1β, IL-2, IL-4, IL-6, IL-8, and TNFα. Results: Mean concentrations of tear film cytokines were lower in the glaucoma group for 8 of 10 cytokines tested. IL-12p70 (3.94±2.19 pg/mL in control vs 2.31±1.156 pg/mL in POAG; P=0.035 was significantly lower in the tear film of patients with newly diagnosed POAG. Conclusion: Proinflammatory cytokines were lower in eye drop-naïve newly diagnosed glaucoma patients. Tear film cytokine profiles may be used as biomarkers of early POAG. Keywords: glaucoma, biomarkers, tear film, cytokines, glaucoma diagnosis, lower limit of detection

Influence of preoperative artificial tears on tear film after phacoemulsification on dry eye of diabetes patients

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Rui Su

2015-05-01

Full Text Available AIM: To discuss the artificial tears on the tear film of diabetic patients with dry eye preoperatively, and the influence on the tear film's fuctional after phacoemulsification.METHODS: Fifty-four diabetic patients with dry eye(60 eyeswere followed up before phacoemulsification. Preoperatively, group A(30 eyes in 28 caseswas treated with Hydroxyl Indican eye drops and group B(30 eyes in 26 caseswas not treated. Postoperatively, both group A and B were treated with Tobramycin Dexamethasone eye drops, Oprah Winfrey Ibuprofen eye drops and Hydroxyl Indican eye drops. Dry eye symptoms, break up time(BUT, Schirmer Ⅰ test(S Ⅰ t, fluorescein stain test(FIwere measured at 3d preoperatively, and 1, 7, 30, 90d postoperatively.RESULTS: At 3d preoperatively, there was no statistical differences between the two groups for dry eye symptoms, BUT, SⅠt, FI(P>0.05. At 1 and 7d postoperatively, there were significant statistical differents between the two groups for dry eye symptoms(PPP>0.05.CONCLUSION: Using artificial tears before phacoemulsification can improve symptoms of the diabetic patients with dry eye and accelerate the recovery of the tear film.

Short-term effect of topical antiglaucoma medication on tear-film stability, tear secretion, and corneal sensitivity in healthy subjects.

Science.gov (United States)

Terai, Naim; Müller-Holz, Matthias; Spoerl, Eberhard; Pillunat, Lutz E

2011-01-01

The purpose of this study was to investigate the short-term effect of topical antiglaucoma medication on tear-film stability, tear secretion, and corneal sensitivity in healthy subjects. In this prospective, double-blind crossover trial, break-up time and basal secretion (Jones test) were measured 60 minutes before, and 30, 60, and 90 minutes after topical antiglaucoma drop application in 30 healthy subjects. Corneal sensitivity was measured 60 minutes before, and five, 10, and 15 minutes after drop application using a Cochet-Bonnet esthesiometer. Reduction of break-up time in the latanoprost group was -23.8% after 30 minutes (P = 0.21), -26.7% after 60 minutes (P = 0.03) and -51.4% after 90 minutes (P ≤ 0.003), which was statistically significant. Reduction of break-up time in all other treatment groups was not statistically significant. The Jones test revealed a significant reduction of basal secretion after application of brimonidine (-17.8%, P = 0.002; -22.5%, P < 0.001; -30.5%, P < 0.001), followed by apraclonidine (-10%, P = 0.06; -20.1%, P = 0.02; -22.1%, P = 0.002), latanoprost (-2.4%, P = 0.64; -18.6%, P = 0.001; -20.1%, P = 0.001) and dorzolamide (-0.5%, P = 0.9; 14.3%, P = 0.018; -17.3%, P = 0.004) at 30, 60, and 90 minutes after drop application. Reduction of basal secretion in all other treatment groups was not statistically significant. Latanoprost showed the most statistically significant reduction in break-up time, and brimonidine showed the most significant reduction in basal secretion of all the glaucoma medications used in this study. In conclusion, our data may be helpful for treatment decisions in glaucoma patients who also suffer from ocular surface problems.

Interaction of lysozyme with a tear film lipid layer model: A molecular dynamics simulation study.

Science.gov (United States)

Wizert, Alicja; Iskander, D Robert; Cwiklik, Lukasz

2017-12-01

The tear film is a thin multilayered structure covering the cornea. Its outermost layer is a lipid film underneath of which resides on an aqueous layer. This tear film lipid layer (TFLL) is itself a complex structure, formed by both polar and nonpolar lipids. It was recently suggested that due to tear film dynamics, TFLL contains inhomogeneities in the form of polar lipid aggregates. The aqueous phase of tear film contains lachrymal-origin proteins, whereby lysozyme is the most abundant. These proteins can alter TFLL properties, mainly by reducing its surface tension. However, a detailed nature of protein-lipid interactions in tear film is not known. We investigate the interactions of lysozyme with TFLL in molecular details by employing coarse-grained molecular dynamics simulations. We demonstrate that lysozyme, due to lateral restructuring of TFLL, is able to penetrate the tear lipid film embedded in inverse micellar aggregates. Copyright © 2017 Elsevier B.V. All rights reserved.

Stability of short wavelength tearing and twisting modes

International Nuclear Information System (INIS)

Waelbroeck, F.L.

1998-01-01

The stability and mutual interaction of tearing and twisting modes in a torus is governed by matrices that generalize the well-known Δ' stability index. The diagonal elements of these matrices determine the intrinsic stability of modes that reconnect the magnetic field at a single resonant surface. The off-diagonal elements indicate the strength of the coupling between the different modes. The author shows how the elements of these matrices can be evaluated, in the limit of short wavelength, from the free energy driving radially extended ballooning modes. The author applies the results by calculating the tearing and twisting Δ' for a model high-beta equilibrium with circular flux surfaces

Local effect of equilibrium current on tearing mode stability

International Nuclear Information System (INIS)

Cozzani, F.

1985-12-01

The local effect of the equilibrium current on the linear stability of low poloidal number tearing modes in tokamaks is investigated analytically. The plasma response inside the tearing layer is derived from fluid theory and the local equilibrium current is shown to couple to the mode dynamics through its gradient, which is proportional to the local electron temperature gradient under the approximations used in the analysis. The relevant eigenmode equations, expressing Ampere's law and the plasma quasineutrality condition, respectively, are suitably combined in a single integral equation, from which a variational principle is formulated to derive the mode dispersion relations for several cases of interest. The local equilibrium current is treated as a small perturbation of the known results for the m greater than or equal to 2 and the m = 1 tearing modes in the collisional regime, and the m greater than or equal to 2 tearing mode in the semicollisional regime; its effect is found to enhance stabilization for the m greater than or equal to 2 drift-tearing mode in the collisional regime, whereas the m = 1 growth rate is very slightly increased and the stabilizing effect of the parallel thermal conduction on the m greater than or equal to 2 mode in the semicollisional regime is slightly reduced

Tearing mode stability of tokamak plasmas with elliptical cross section

International Nuclear Information System (INIS)

Carreras, B.A.; Holmes, J.A.; Hicks, H.R.; Lynch, V.E.

1981-02-01

The effect of the ellipticity of the plasma cross section on tearing mode stability is investigated. The induced coupling between modes is shown to be destabilizing; however, the modification of the equilibrium tends to stabilize the tearing modes. The net effect depends on the manner in which the equilibrium is modified as the plasma cross-section shape is changed

Effect of contact lens wear and a near task on tear film break-up.

Science.gov (United States)

Jansen, Meredith E; Begley, Carolyn G; Himebaugh, Nikole H; Port, Nicholas L

2010-05-01

To study the effect of extrinsic controls on blinking by examining blink parameters and tear stability among adapted soft contact lens (CL) wearers performing tasks that require varying amounts of visual concentration. The Demographic Questionnaire, Contact Lens Dry Eye Questionnaire, and Current Symptoms Questionnaire were completed by 15 adapted soft CL wearers (nine females). Three 55 s simultaneous measurements of tear film stability via retroillumination and blinking were obtained with a slit-lamp biomicroscope and 200 Hz video camera while subjects listened to music and played a video game with and without their habitual CLs. Interblink interval (IBI) and blink amplitude (BA) were calculated. The area of break-up (AB) was calculated for the retroillumination image before each blink. The Current Symptoms Questionnaire was completed four times throughout testing. With the game compared to music, IBI was significantly longer and BA significantly decreased without CLs (p or = 0.5579, p or = 0.6262, p or = 0.5064, p film instability increased. Blinking frequency also increased, but it remained high when subjects played the game, and symptoms of ocular irritation increased. This suggests that wearing soft CLs, even when fully adapted, provides enough extrinsic ocular surface stimulation to override internal controls and affect blink parameters.

Effect of Time after Anterior Cruciate Ligament Tears on Proprioception and Postural Stability.

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Dae-Hee Lee

Full Text Available This study was designed to compare proprioception and postural stability in patients with acute (time from injury ≤ 3 months and chronic (time from injury > 3 months ACL tears, and to evaluate the correlation between time interval after ACL injury and proprioception. Thigh muscle strength, postural stability, and joint position sense were compared in 48 patients with acute ACL tears and in 28 with chronic ACL tears. Maximal torque (60°/sec of the quadriceps and hamstring was evaluated using an isokinetic testing device. Postural stability was determined from the anterior-posterior (APSI, medial-lateral (MLSI, and overall (OSI stability indices using stabilometry. Joint position sense was also tested by reproduction of passive positioning (RPP. Muscle strengths and stability indices on both the involved and uninvolved sides were similar in the acute and chronic ACL tear groups. RPP on the involved side was significantly greater in the chronic than in the acute ACL tear group (7.8° vs. 5.6°, P = 0.041. Two of three stability indices (APSI, OSI and RPP were significantly greater on the involved than the uninvolved side in the chronic ACL tear group.

The importance of the precorneal tear film for the quality of optical imaging.

OpenAIRE

Rieger, G

1992-01-01

The optical function of the eye critically depends on the presence of an intact precorneal tear film. Abnormalities of the tear film such as those occurring in the dry eye syndrome or in otherwise irritated eyes may interfere with vision. In 30 patients with dry eyes artificial tears were found to produce statistically significant improvement of vision (p less than 0.001) while no significant changes were seen in the untreated partner eyes. Static perimetry in another 30 patients using the 'm...

Surface Properties of Squalene/Meibum Films and NMR Confirmation of Squalene in Tears

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Slavyana Ivanova

2015-09-01

Full Text Available Squalene (SQ possesses a wide range of pharmacological activities (antioxidant, drug carrier, detoxifier, hydrating, emollient that can be of benefit to the ocular surface. It can come in contact with human meibum (hMGS; the most abundant component of the tear film lipid layer as an endogenous tear lipid or from exogenous sources as eyelid sebum or pharmaceuticals. The aims of this study were to determine (i if SQ is in tear lipids and (ii its influence on the surface properties of hMGS films. Heteronuclear single quantum correlation NMR confirmed 7 mol % SQ in Schirmer’s strips extracts. The properties of SQ/hMGS pseudo-binary films at the air/water interface were studied with Langmuir surface balance, stress-relaxation dilatational rheology and Brewster angle microscopy. SQ does not possess surfactant properties. When mixed with hMGS squalene (i localized over the layers’ thinner regions and (ii did not affect the film pressure at high compression. Therefore, tear SQ is unlikely to instigate dry eye, and SQ can be used as a safe and “inert” ingredient in formulations to protect against dry eye. The layering of SQ over the thinner film regions in addition to its pharmacological properties could contribute to the protection of the ocular surface.

Effectiveness and comfort of Oculus Keratograph on tear film function test before corneal refractive surgery

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Peng Zhang

2017-08-01

Full Text Available AIM: To explore correlation, consistency and comfort between traditional tear film examination methods and Oculus Keratograph. METHODS: A retrospective study. Totally 101 cases(101 eyeswere diagnosed myopia and then accepted LASEK(laser epithelial keratomileusis. Non-invasive tear film break-up time(NIBUT, lower tear meniscus height(LTMHwere measured with Oculus Keratograph, fluorescein tear film break-up time(fl-BUTand Schimer Ⅰ test(SⅠtwere performed on all cases. The correlations analysis between NIBUT and fl-BUT, LTMH and SⅠt were performed by Spearman rank correlation, consistency check between NIBUT and fl-BUT by Bland-Altman analysis. Visual analogue scale(VASwas applied on evaluating the comfort of two kinds of examination methods. RESULTS: LTMH and SⅠt showed positive correlation(rs=0.346, P=0.001. NIBUT and fl-BUT showed positive correlation(rs=0.393, P=0.001, 95% consistency limits range -9.62 to 14.18 in Bland-Altman Figure. There was significant difference between VAS of NIBUT and VAS of fl-BUT(z=-2.324, P=0.020. There was significant difference between VAS of LTMH and VAS of SⅠt(z=-8.845,P=0.001.CONCLUSION: Oculus Keratograph can objectively measure NIBUT and LTMH, and was more comfortable than traditional tear film examination methods. It can effectively assess tear film function before corneal refractive surgery.

The influence of non-polar lipids on tear film dynamics

KAUST Repository

Bruna, M.; Breward, C.  J.  W.

2014-01-01

© 2014 Cambridge University Press. In this paper we examine the effect that physiological non-polar lipids, residing on the surface of an aqueous tear film, have on the film evolution. In our model we track the evolution of the thickness of the non

The ocular surface and tear film and their dysfunction in dry eye disease.

Science.gov (United States)

Rolando, M; Zierhut, M

2001-03-01

The ocular surface, tear film, lacrimal glands, and eyelids act as a functional unit to preserve the quality of the refractive surface of the eye and to resist injury and protect the eye against changing bodily and environmental conditions. Events that disturb the homeostasis of this functional unit can result in a vicious cycle of ocular surface disease. The tear film is the most dynamic structure of the functional unit, and its production and turnover is essential to maintaining the health of the ocular surface. Classically, the tear film is reported to be composed of three layers: the mucin, aqueous, and lipid layers. The boundaries and real thickness of such layers is still under discussion. A dysfunction of any of these layers can result in dry eye disease.

Computed tear film and osmolarity dynamics on an eye-shaped domain

Science.gov (United States)

Li, Longfei; Braun, Richard J.; Driscoll, Tobin A.; Henshaw, William D.; Banks, Jeffrey W.; King-Smith, P. Ewen

2016-01-01

The concentration of ions, or osmolarity, in the tear film is a key variable in understanding dry eye symptoms and disease. In this manuscript, we derive a mathematical model that couples osmolarity (treated as a single solute) and fluid dynamics within the tear film on a 2D eye-shaped domain. The model includes the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis and tear fluid supply and drainage. The governing system of coupled non-linear partial differential equations is solved using the Overture computational framework, together with a hybrid time-stepping scheme, using a variable step backward differentiation formula and a Runge–Kutta–Chebyshev method that were added to the framework. The results of our numerical simulations provide new insight into the osmolarity distribution over the ocular surface during the interblink. PMID:25883248

Comparative Analysis of Tear Film Levels of Inflammatory Mediators in Contact Lens Users.

Science.gov (United States)

Yüksel Elgin, Cansu; İskeleli, Güzin; Talaz, Serap; Akyol, Sibel

2016-04-01

To compare tear films levels of various inflammatory cytokines in asymptomatic contact lens (CL) users. CL users of rigid gas-permeable CLs (RGPCL) (group 1) or silicone hydrogel CLs (SiHCL) (group 2) were compared with non-CL-using healthy subjects (group 3). Tear samples were collected from subjects in each group after ensuring that there were no complications secondary to CL wear in the CL-wearing participants. Tear-film levels of interleukins (ILs)-1β, -6, and -8; granulocyte-macrophage colony-stimulating factor (GM-CSF) (using the Luminex method); and leukotriene B4 (LTB4) (using the ELISA method) were determined. Cytokine levels were compared among the three groups using analysis-of-variance (ANOVA) and Kruskall-Wallis tests. There were significant differences in concentrations of IL-1β, GM-CSF and LTB4 among the three groups (p = 0.002, p = 0.021 and p = 0.009, respectively), as shown by the Kruskall-Wallis test comparing all three groups for the three cytokines. There were no significant differences for IL-6 and IL-8 (p = 0.079 and 0.094, respectively) when all three groups were compared. There were substantial statistically significant differences between RGPCL users, SiHCL users and control subjects in levels of tear film cytokines. Although CL users were asymptomatic, changes in tear-film levels of several important inflammatory mediators revealed that a chronic inflammatory process occurs during CL wear.

Neoclassical effects on the stabilization of tearing mode by current modulation

Energy Technology Data Exchange (ETDEWEB)

Yang, Xiaoqing, E-mail: inkyang@mail.ustc.edu.cn; Wang, Shaojie; Yang, Weihong [Department of Modern Physics, University of Science and Technology of China, Hefei, 230026 (China)

2014-02-15

The neoclassical effects on the stabilization of tearing modes by current modulation have been investigated. Neoclassical effects enhance the resistivity and reduce the resistive diffusion time of the modulation current. Therefore, the oscillating current can penetrate deeper into the plasma. With an oscillating loop voltage, the plasma oscillates radially at the Ware-pinch velocity. These neoclassical effects improve the efficiency of tearing mode stabilization by the current modulation.

Glenohumeral stability in simulated rotator cuff tears

NARCIS (Netherlands)

Steenbrink, F.; Groot, J.H.; Veeger, H.E.J.; Helm, F.C.; Rozing, P.M.

2009-01-01

Rotator cuff tears disrupt the force balance in the shoulder and the glenohumeral joint in particular, resulting in compromised arm elevation torques. The trade-off between glenohumeral torque and glenohumeral stability is not yet understood. We hypothesize that compensation of lost abduction torque

Changes of tear film after LASIK with corneal flap created by femtosecond laser and microkeratome

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Yuan Zhang

2014-09-01

Full Text Available AIM: To observe the changes of tear film on the patients after laser in situ keratomileusis(LASIKwith corneal flap created by femtosecond laser and microkeratome.METHODS: Totally 150 patients(300 eyeswith myopia received operation of LASIK. Patients were divided into two groups according to the methods of making corneal flap. The patients of group one were assigned to receiving LASIK with corneal flap creation by Intralase femtosecond laser(190 eyes of 95 patients, group two were assigned to receiving LASIK with corneal flap creation by microkeratome(110 eyes of 55 patients. Dry eye symptom score, tear break-up time(BUT, Schirmer Ⅰ test(S I t, corneal fluorescein staining(FLwere recorded preoperatively and postoperatively at 1wk; 1, 3 and 6mo. RESULTS: Dry eye symptom score: there existed obvious differences at 1wk; 1, 3mo between two groups(PP>0.05. BUT: there existed obvious differences at 1wk, 1, 3mo between two groups(PP>0.05. SchirmerⅠ test: there existed obvious differences in the 1wk, 1, 3mo between two groups(PP>0.05. FL: there existed obvious differences in the 1wk, 1, 3mo between two groups(PP>0.05.CONCLUSION: The early stability of tear film decrease after operation in both of the two groups. The dry eye symptoms are lighter and recover faster.

Structure-function relationship of tear film lipid layer: A contemporary perspective.

Science.gov (United States)

Georgiev, Georgi As; Eftimov, Petar; Yokoi, Norihiko

2017-10-01

Tear film lipid layer (TFLL) stabilizes the air/tear surface of the human eye. Meibomian gland dysfunction (MGD) resulting in quantitative and qualitative modifications of TFLL major (>93%) component, the oily secretion of meibomian lipids (MGS), is the world leading cause of dry eye syndrome (DES) with up to 86% of all DES patients showing signs of MGD. Caused by intrinsic factors (aging, ocular and general diseases) and by extrinsic everyday influences like contact lens wear and extended periods in front of a computer screen, DES (resulting in TF instability, visual disturbances and chronic ocular discomfort) is the major ophthalmic public health disease of the present time affecting the quality of life of 10-30% of the human population worldwide. Therefore there is a pressing need to summarize the present knowledge, contradictions and open questions to be resolved in the field of TFLL composition/structure/functions relationship. The following major aspects are covered by the review: (i) Do we have a reliable mimic for TFLL: MGS vs contact lens lipid extracts (CLLE) vs lipid extracts from whole tears. Does TFLL truly consist of lipids only or it is important to keep in mind the TF proteins as well?; (ii) Structural properties of TFLL and of its mimics in health and disease in vitro and in vivo. How the TFLL uniformity and thickness ensures the functionality of the lipid layer (barrier to evaporation, surface properties, TF stability etc.); (iii) What are the main functions of the TFLL? In this aspect an effort is done to emphasize that there is no single main function of TFLL but instead it simultaneously fulfills plethora of functions: suppresses the evaporation (alone or probably in cooperation with other TF constituents) of the aqueous tears; stabilizes (due to its surface properties) the air/tear surface at eye opening and during the interblink interval; and even acts as a first line of defense against bacterial invasion due to its detergency action on the

Effect of laser in situ keratomileusis with corneal flap created by femtosecond laser on tear film detected by Keratograph in different age groups

Directory of Open Access Journals (Sweden)

Yu-Xia Zhang

2016-03-01

Full Text Available AIM:To explore the changes of tear film detected by Keratograph in the patients after laser in situ keratomileusis(LASIKwith corneal flap created by femtosecond laser. METHODS: Totally 75 myopic patients(150 eyeswere enrolled who underwent femtosecond laser LASIK from July 2014 to June 2015, including patientsRESULTS: Before surgeries, the dry eye symptoms score of three groups had no significant difference(P>0.05. After surgeries, there were significant difference at each follow-up time among the three groups on symptoms score(PPCONCLUSION: LASIK can affect the dry eye symptoms and the stability of tear film, which decreased by postoperative time. And the index recovered to preoperative levels earlier in younger patients.

Application of tearing modulus stability concepts to nuclear piping. Final report

International Nuclear Information System (INIS)

Cotter, K.H.; Chang, H.Y.; Zahoor, A.

1982-02-01

The recently developed tearing modulus stability concept was successfully applied to several boiling water reactor (BWR) and pressurized water reactor (PWR) piping systems. Circumferentially oriented through-the-thickness cracks were postulated at numerous locations in each system. For each location, the simplified tearing stability methods developed in USNRC Report NUREG/CR-0838 were used to determine crack stability. The J-T diagram was used to present the results of the computations. The piping systems considered included Type 304 stainless steel as well as A106 carbon steel materials. These systems were analyzed using the piping analysis computer code MINK

Tear film and ocular surface assessment in psoriasis.

Science.gov (United States)

Aragona, Emanuela; Rania, Laura; Postorino, Elisa Imelde; Interdonato, Alberto; Giuffrida, Roberta; Cannavò, Serafinella Patrizia; Puzzolo, Domenico; Aragona, Pasquale

2018-03-01

Psoriasis is a skin disease with also systemic involvement: its impact on the eye is not well established and often clinically underestimated. Aim of this study was to investigate the presence of ocular discomfort symptoms and of ocular surface changes in a population of patients with psoriasis. For this cross-sectional, comparative study, 66 patients with psoriasis were subdivided according to the presence of arthritis and to the use of biological therapy. All patients underwent clinical evaluation with the following tests: Ocular Surface Disease Index Questionnaire, Tearscope examination, meibometry, tear film breakup time, corneal and conjunctival fluorescein staining, Schirmer I test, corneal aesthesiometry, meibomian gland dysfunction (MGD) assessment and conjunctival impression cytology. 28 healthy subjects were also enrolled and treated with the same clinical tests. A statistical analysis of the results was performed. Patients with psoriasis showed a significant deterioration of the ocular surface tests, if compared with healthy subjects, demonstrated by tear film lipid layer alteration, tear film instability, corneal and conjunctival epithelial suffering and mild squamous metaplasia at impression cytology. No differences were found in ocular surface test results of the psoriatic group when patients were divided according to the presence of arthritis, whereas the anti-inflammatory treatment with biological drugs demonstrated a significant improvement of corneal stain and MGD. Our findings suggest that the ocular surface involvement in patients with psoriasis indicates the need of periodic ophthalmological examinations to diagnose the condition and allow a proper treatment, so contributing to the amelioration of patients' quality of life. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Parallel definition of tear film maps on distributed-memory clusters for the support of dry eye diagnosis.

Science.gov (United States)

González-Domínguez, Jorge; Remeseiro, Beatriz; Martín, María J

2017-02-01

The analysis of the interference patterns on the tear film lipid layer is a useful clinical test to diagnose dry eye syndrome. This task can be automated with a high degree of accuracy by means of the use of tear film maps. However, the time required by the existing applications to generate them prevents a wider acceptance of this method by medical experts. Multithreading has been previously successfully employed by the authors to accelerate the tear film map definition on multicore single-node machines. In this work, we propose a hybrid message-passing and multithreading parallel approach that further accelerates the generation of tear film maps by exploiting the computational capabilities of distributed-memory systems such as multicore clusters and supercomputers. The algorithm for drawing tear film maps is parallelized using Message Passing Interface (MPI) for inter-node communications and the multithreading support available in the C++11 standard for intra-node parallelization. The original algorithm is modified to reduce the communications and increase the scalability. The hybrid method has been tested on 32 nodes of an Intel cluster (with two 12-core Haswell 2680v3 processors per node) using 50 representative images. Results show that maximum runtime is reduced from almost two minutes using the previous only-multithreaded approach to less than ten seconds using the hybrid method. The hybrid MPI/multithreaded implementation can be used by medical experts to obtain tear film maps in only a few seconds, which will significantly accelerate and facilitate the diagnosis of the dry eye syndrome. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Tear Film and Ocular Surface Changes in Patients Receiving Systemic Isotretinoin

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Ebru Nevin Çetin

2013-10-01

Full Text Available Purpose: Our aim in this study was to assess the ocular surface and tear film changes in acne vulgaris patients receiving systemic isotretinoin. Material and Method: Twenty-two eyes of 22 patients who received oral isotretinoin (roaccutane®, 0.7 mg/kg/day for nodular acne vulgaris were enrolled in this prospective study. Tear film break-up time (BUT, Schirmer 1 test scores with anesthesia, ocular surface disease index (OSDI scores and conjunctival impression cytology scores were recorded before treatment and at 3- and 6-month visits following the beginning of treatment. Results: BUT values decreased and OSDI scores significantly increased at 3 months after treatment (p=0.007 and p=0.018, paired samples test. Schirmer scores did not significantly change by isotretinoin treatment. Of 9 eyes with impression cytology specimens, 4 revealed normal conjunctival findings before treatment. At the 3rd month, there was an increase in the scores characterized by decrease of Goblet cells, and at 6 months of treatment, normal conjunctival findings did not exist in any of the patients (p=0.004, Friedman test. Discussion: Systemic isotretinoin treatment can cause alterations in the tear film and cause dry eye symptoms. (Turk J Ophthalmol 2013; 43: 309-12

[Epidemiologic study of tear film lipid layer thickness measurement in the population of Taishitun Community in Beijing].

Science.gov (United States)

Liang, Q F; Du, X H; Su, Y D; Wang, N L; Wei, Z J; Labbé, Antoine

2017-07-11

Objective: To investigate the distribution of tear film lipid layer thickness (LLT) and the relationship between symptoms and signs of dry eye and tear film LLT in the population of Taishitun Community in Beijing. Methods: A cross-sectional study. From May 2016 to August 2016, three streets of Taishitun Community were randomly selected as survey districts and 540 persons were taken as investigation subjects. Every participant completed 6 items of dry eye examinations as follows: questionnaire (Ocular Surface Disease Index, OSDI), measurement of tear film LLT, tear film break-up time (TBUT), corneal and conjunctival staining, SchirmerⅠtest and the infrared meibomian photography. According to their age, all participants were divided into four groups: junior group (analysis and multivariate Logistic regression analysis, distribution of the variables of LLT and the relationship between dry eye symptoms and LLT were studied. Results: A total of 473 residents finally participated in this study, and the response ratio was 87.6%. The values of LLT were normally distributed. The average LLT was (59.87±18.50) nm [(60.16±19.15) nm in males and (59.67±18.57) nm in females], and the comparison of LLT with different genders was not statistically significant ( t= 0.198, P= 0.843). The tear film LLT of four different age groups had statistical significance ( F= 15.092, P0.05. F= 0.538, P >0.05). In the OSDI symptom questionnaire, only blurred vision and decreased visual acuity were related to the tear film LLT ( Pfilm LLT ( P> 0.05). Conclusions: In Taishitun Community of Beijing, the values of tear film LLT had a normal distribution. The LLT was positively correlated with age, but inversely correlated with the severity of the symptoms of dry eye. There was no significant correlation between the LLT and the TBUT, SchirmerⅠtest result and meibomian gland loss rate. (Chin J Ophthalmol, 2017, 53: 495-501) .

Comparative study of lubricating properties of tear substitutes Systane® Ultra and Visine® Clear Tears

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Yu. A. Pavlova

2014-07-01

Full Text Available Purpose: To compare tear substitutive properties of Systane® Ultra and Visine® Clear Tears in dry eye therapy.Methods: 20 patients with dry eye due to chronic blepharoconjunctivitis and 20 patients with neurotrophic dry eye following corneal refractive surgery were examined. Treatment schedule was the following: in the first 7 days, Systane® Ultra was instilled in the right eye and Visine® Clear Tears was instilled in the left eye, while from day 8 to day 30, only one medicine selected by the patient was applied. Their efficacy was measured by tear film stability and patients’ subjective sensations.Results: Norn test results improved to day 7 in patients with dry eye following corneal refractive surgery and to day 30 in patients with dry eye due to blepharoconjunctivitis regardless of eye drops used. As to patients’ comfort, Systane® Ultra is preferable to Visine® Clear Tears.Conclusion: Systane® Ultra is therapeutically similar to but preferable to Visine® Clear Tears due to good tolerability.

Comparative study of lubricating properties of tear substitutes Systane® Ultra and Visine® Clear Tears

Directory of Open Access Journals (Sweden)

Yu. A. Pavlova

2013-01-01

Full Text Available Purpose: To compare tear substitutive properties of Systane® Ultra and Visine® Clear Tears in dry eye therapy.Methods: 20 patients with dry eye due to chronic blepharoconjunctivitis and 20 patients with neurotrophic dry eye following corneal refractive surgery were examined. Treatment schedule was the following: in the first 7 days, Systane® Ultra was instilled in the right eye and Visine® Clear Tears was instilled in the left eye, while from day 8 to day 30, only one medicine selected by the patient was applied. Their efficacy was measured by tear film stability and patients’ subjective sensations.Results: Norn test results improved to day 7 in patients with dry eye following corneal refractive surgery and to day 30 in patients with dry eye due to blepharoconjunctivitis regardless of eye drops used. As to patients’ comfort, Systane® Ultra is preferable to Visine® Clear Tears.Conclusion: Systane® Ultra is therapeutically similar to but preferable to Visine® Clear Tears due to good tolerability.

Solute Dynamics and Imaging in the Tear Film on an Eye-shaped Domain

Science.gov (United States)

Braun, R. J.; Li, Longfei; Henshaw, William; Driscoll, Tobin; King-Smith, P. E.

2015-11-01

The concentration of ions in the tear film (osmolarity) is a key variable in understanding dry eye symptoms and disease, yet its global distribution is not available; direct measurements are restricted to a region near the temporal canthus. It has been suggested that imaging methods that use solutes such as fluorescein can be used as a proxy for estimating the osmolarity. The concentration of fluorescein is not measured directly either but the intensity as a function of concentration and thickness of the film is well established. We derived a mathematical model that couples multiple solutes and fluid dynamics within the tear film on a 2D eye-shaped domain. The model includes the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis, fluorescence and tear fluid supply and drainage. We solved the governing system of coupled nonlinear PDEs using the Overture computational framework developed at LLNL, together with a hybrid time stepping scheme (using variable step BDF and RKC). Results of our numerical simulations provide new insight about the osmolarity distribution and its connection with images obtained in vivo over the whole ocular surface and in local regions of tear thinning due to evaporation and other effects. This work was supported in part by NSF grants 1022706 and 1412085, and NIH grant 1R01EY021794.

Stability of tearing modes in tokamak plasmas

International Nuclear Information System (INIS)

Hegna, C.C.; Callen, J.D.

1994-02-01

The stability properties of m ≥ 2 tearing instabilities in tokamak plasmas are analyzed. A boundary layer theory is used to find asymptotic solutions to the ideal external kink equation which are used to obtain a simple analytic expression for the tearing instability parameter Δ'. This calculation generalizes previous work on this topic by considering more general toroidal equilibria (however, toroidal coupling effects are ignored). Constructions of Δ' are obtained for plasmas with finite beta and for islands that have nonzero width. A simple heuristic estimate is given for the value of the saturated island width when the instability criterion is violated. A connection is made between the calculation of the asymptotic matching parameter in the finite beta and island width case to the nonlinear analog of the Glasser effect

Tear film dynamics with evaporation, wetting, and time-dependent flux boundary condition on an eye-shaped domain

Science.gov (United States)

Li, Longfei; Braun, R. J.; Maki, K. L.; Henshaw, W. D.; King-Smith, P. E.

2014-01-01

We study tear film dynamics with evaporation on a wettable eye-shaped ocular surface using a lubrication model. The mathematical model has a time-dependent flux boundary condition that models the cycles of tear fluid supply and drainage; it mimics blinks on a stationary eye-shaped domain. We generate computational grids and solve the nonlinear governing equations using the OVERTURE computational framework. In vivo experimental results using fluorescent imaging are used to visualize the influx and redistribution of tears for an open eye. Results from the numerical simulations are compared with the experiment. The model captures the flow around the meniscus and other dynamic features of human tear film observed in vivo. PMID:24926191

Application of texture analysis in tear film surface assessment based on videokeratoscopy

Directory of Open Access Journals (Sweden)

David Alonso-Caneiro

2013-10-01

Conclusions: Texture analysis of videokeratoscopy images is applicable to study tear film anomalies in dry eye subjects. The proposed technique appears to have demonstrated its clinical relevance and utility.

Review of tearing mode stabilization by RF power in tokamaks

International Nuclear Information System (INIS)

Giruzzi, G.; Zabiego, M.; Zohm, H.

1999-01-01

Control of tearing modes by means of heating and current drive inside the magnetic islands is one of the most important applications of RF power in tokamak reactors. The theoretical basis of this concept is reviewed, focusing on aspects related to RF-plasma interaction. Applications to the stabilization of neoclassical tearing modes in ITER by Electron Cyclotron Current Drive are presented to illustrate the basic physical dependences. The most significant experimental results and prospects for future applications are also discussed

Modelling the evaporation of a tear film over a contact lens.

Science.gov (United States)

Talbott, Kevin; Xu, Amber; Anderson, Daniel M; Seshaiyer, Padmanabhan

2015-06-01

A contact lens (CL) separates the tear film into a pre-lens tear film (PrLTF), the fluid layer between the CL and the outside environment, and a post-lens tear film (PoLTF), the fluid layer between the CL and the cornea. We examine a model for evaporation of a PrLTF on a modern permeable CL allowing fluid transfer between the PrLTF and the PoLTF. Evaporation depletes the PrLTF, and continued evaporation causes depletion of the PoLTF via fluid loss through the CL. Governing equations include Navier-Stokes, heat and Darcy's equations for the fluid flow and heat transfer in the PrLTF and porous layer. The PoLTF is modelled by a fixed pressure condition on the posterior surface of the CL. The original model is simplified using lubrication theory for the PrLTF and CL applied to a sagittal plane through the eye. We obtain a partial differential equation (PDE) for the PrLTF thickness that is first-order in time and fourth-order in space. This model incorporates evaporation, conjoining pressure effects in the PrLTF, capillarity and heat transfer. For a planar film, we find that this PDE can be reduced to an ordinary differential equation (ODE) that can be solved analytically or numerically. This reduced model allows for interpretation of the various system parameters and captures most of the basic physics contained in the model. Comparisons of ODE and PDE models, including estimates for the loss of fluid through the lens due to evaporation, are given. © The Authors 2014. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

Application of tearing modulus stability concepts to nuclear piping. Final report. [PWR; BWR

Energy Technology Data Exchange (ETDEWEB)

Cotter, K.H.; Chang, H.Y.; Zahoor, A.

1982-02-01

The recently developed tearing modulus stability concept was successfully applied to several boiling water reactor (BWR) and pressurized water reactor (PWR) piping systems. Circumferentially oriented through-the-thickness cracks were postulated at numerous locations in each system. For each location, the simplified tearing stability methods developed in USNRC Report NUREG/CR-0838 were used to determine crack stability. The J-T diagram was used to present the results of the computations. The piping systems considered included Type 304 stainless steel as well as A106 carbon steel materials. These systems were analyzed using the piping analysis computer code MINK.

Management of the ocular surface and tear film before, during, and after laser in situ keratomileusis.

Science.gov (United States)

Albietz, Julie M; Lenton, Lee M

2004-01-01

To identify evidence-based, best practice strategies for managing the ocular surface and tear film before, during, and after laser in situ keratomileusis (LASIK). After a comprehensive review of relevant published literature, evidence-based recommendations for best practice management strategies are presented. Symptoms of ocular irritation and signs of dysfunction of the integrated lacrimal gland/ocular surface functional gland unit are common before and after LASIK. The status of the ocular surface and tear film before LASIK can impact surgical outcomes in terms of potential complications during and after surgery, refractive outcome, optical quality, patient satisfaction, and the severity and duration of dry eye after LASIK. Before LASIK, the health of the ocular surface should be optimized and patients selected appropriately. Dry eye before surgery and female gender are risk factors for developing chronic dry eye after LASIK. Management of the ocular surface during LASIK can minimize ocular surface damage and the risk of adverse outcomes. Long-term management of the tear film and ocular surface after LASIK can reduce the severity and duration of dry eye symptoms and signs. Strategies to manage the integrated ocular surface/lacrimal gland functional unit before, during, and after LASIK can optimize outcomes. As problems with the ocular surface and tear film are relatively common, attention should focus on the use and improvement of evidence-based management strategies.

Strong toroidal effects on tokamak tearing mode stability in the hybrid and conventional scenarios

International Nuclear Information System (INIS)

Ham, C J; Connor, J W; Cowley, S C; Gimblett, C G; Hastie, R J; Hender, T C; Martin, T J

2012-01-01

The hybrid scenario is thought to be an important mode of operation for the ITER tokamak. Analytic and numerical calculations demonstrate that toroidal effects at finite β have a strong influence on tearing mode stability of hybrid modes. Indeed, they persist in the large aspect ratio limit, R/a → ∞. A similar strong coupling effect is found between the m = 1, n = 1 harmonic and the m = 2, n = 1 harmonic if the minimum safety factor is less than unity. In both cases the tearing stability index, Δ′ increases rapidly as β approaches ideal marginal stability, providing a potential explanation for the onset of linearly unstable tearing modes. The numerical calculations have used an improved version of the T7 code (Fitzpatrick et al 1993 Nucl. Fusion 33 1533), and complete agreement is obtained with the analytic theory for this demanding test of the code. (paper)

Adsorption of lysozyme to phospholipid and meibomian lipid monolayer films.

Science.gov (United States)

Mudgil, Poonam; Torres, Margaux; Millar, Thomas J

2006-03-15

It is believed that a lipid layer forms the outer layer of the pre-ocular tear film and this layer helps maintain tear film stability by lowering its surface tension. Proteins of the aqueous layer of the tear film (beneath the lipid layer) may also contribute to reducing surface tension by adsorbing to, or penetrating the lipid layer. The purpose of this study was to compare the penetration of lysozyme, a tear protein, into films of meibomian lipids and phospholipids held at different surface pressures to determine if lysozyme were part of the surface layer of the tear film. Films of meibomian lipids or phospholipids were spread onto the surface of a buffered aqueous subphase. Films were compressed to particular pressures and lysozyme was injected into the subphase. Changes in surface pressure were monitored to determine adsorption or penetration of lysozyme into the surface film. Lysozyme penetrated a meibomian lipid film at all pressures tested (max=20 mN/m). It also penetrated phosphatidylglycerol, phosphatidylserine or phosphatidylethanolamine lipid films up to a pressure of 20 mN/m. It was not able to penetrate a phosphatidylcholine film at pressures >or=10 mN/m irrespective of the temperature being at 20 or 37 degrees C. However, it was able to penetrate it at very low pressures (<10 mN/m). Epifluorescence microscopy showed that the protein either adsorbs to or penetrates the lipid layer and the pattern of mixing depended upon the lipid at the surface. These results indicate that lysozyme is present at the surface of the tear film where it contributes to decreasing the surface tension by adsorbing and penetrating the meibomian lipids. Thus it helps to stabilize the tear film.

Stability of multihelical tearing modes in shaped tokamaks

International Nuclear Information System (INIS)

Kerner, W.; Tasso, H.

1982-03-01

The stability of multihelical tearing modes in tokamaks with shaped cross-sections is determined numerically. The method allows inclusion of a large number of singular surfaces resolved with high accuracy. Poloidal and radial couplings are discussed and the convergence is well understood. High poloidal m number modes are found to be unstable for typical equilibria. Completely stable current distributions have been constructed for D-shaped plasmas. (orig.)

Evaluating tear clearance rate with optical coherence tomography.

Science.gov (United States)

Garaszczuk, Izabela K; Mousavi, Maryam; Cervino Exposito, Alejandro; Bartuzel, Maciej M; Montes-Micó, Robert; Iskander, D Robert

2018-02-01

To assess the early-phase of tear clearance rate (TCR) with anterior segment optical coherence tomography (OCT) and to determine the association between TCR and other clinical measures of the tear film in a group of young subjects with different levels of tear film quality. TCR was classified as the percentage decrease of subject's inferior tear meniscus height 30s after instillation of 5μl 0.9% saline solution. Fifty subjects (32F and 18M) aged (mean±standard deviation) 25.5±4.3 years volunteered for the study. It consisted of a review of medical history, Ocular Surface Disease Index (OSDI) questionnaire, tear film osmolarity measurements, slit lamp examination and TCR estimation based on dynamic measurements of the lower tear meniscus with OCT. Estimates of TCR were contrasted against subject age and tear film measures commonly used for dry eye diagnosis, which includes OSDI score, fluorescein tear film break-up time (FBUT), tear meniscus height (TMH), blinking frequency, tear film osmolarity and corneal staining. The group mean TCR was 29±13% and 36±19% respectively after 30 and 60s margin after saline solution instillation. Statistically significant correlations were found between TCR and FBUT (r 2 =0.319, placrimal functional unit. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Expression of Lipid Peroxidation Markers in the Tear Film and Ocular Surface of Patients with Non-Sjogren Syndrome: Potential Biomarkers for Dry Eye Disease.

Science.gov (United States)

Choi, Won; Lian, Cui; Ying, Li; Kim, Ga Eon; You, In Cheon; Park, Soo Hyun; Yoon, Kyung Chul

2016-09-01

To investigate the expression of lipid peroxidation markers in the tear film and ocular surface and their correlation with disease severity in patients with dry eye disease. The concentrations of hexanoyl-lysine (HEL), 4-hydroxy-2-nonenal (HNE), and malondialdehyde (MDA) were measured with enzyme-linked immunosorbent assays in tears obtained from 44 patients with non-Sjogren syndrome dry eye and 33 control subjects. The correlations between the marker levels and the tear film and ocular surface parameters, including tear film break-up time (BUT), Schirmer tear value, tear clearance rate, keratoepitheliopathy scores, corneal sensitivity, conjunctival goblet cell density, and symptom score, were analyzed. The expression of the lipid peroxidation markers HEL, 4-HNE, and MDA in the conjunctiva was evaluated using immunohistochemistry. The concentrations of HEL, 4-HNE, and MDA were 279.84 ± 69.98 nmol/L, 0.02 ± 0.01 μg/mL, and 3.80 ± 1.05 pmol/mg in control subjects and 283.21 ± 89.67 nmol/L (p = 0.97), 0.20 ± 0.03 μg/mL (p dry eye patients. 4-HNE and MDA levels significantly correlated with BUT, Schirmer tear value, tear clearance rate, keratoepitheliopathy scores, conjunctival goblet cell density, and symptom score (p dry eye patients. The expression of late lipid peroxidation markers, 4-HNE and MDA, increases in the tear film and ocular surface of patients with dry eye. The levels correlate with various tear film and ocular surface parameters and may reflect the severity of dry eye disease.

Randomized Controlled Study to Investigate the Effect of Topical Diquafosol Tetrasodium on Corneal Sensitivity in Short Tear Break-Up Time Dry Eye.

Science.gov (United States)

Kaido, Minako; Kawashima, Motoko; Shigeno, Yuta; Yamada, Yoshiaki; Tsubota, Kazuo

2018-05-01

Complex mechanisms underlie dry eye (DE) symptom provocation. In particular, corneal hypersensitivity may provoke symptoms in short tear break-up time (BUT) DE characterized by tear film instability. We hypothesized that improved tear film stability may alleviate corneal sensitivity in patients with short tear BUT DE. Therefore, we investigated the effect of topical diquafosol tetrasodium (DQS) on corneal sensitivity in unstable tear film DE. This prospective, randomized study included 27 subjects (age: 39.1 ± 8.4 years; range: 25-59 years) with short tear BUT DE, defined based on the presence of DE symptoms and tear film instability. Subjects were randomly divided into DQS (3% DQS, 12 subjects) and artificial tear (AT; preservative-free AT, 15 subjects) groups. Subjects applied the medication 6 times a day for 5 weeks. The perception of touch (S-touch) and pain (S-pain) sensitivity was measured using a Cochet-Bonnet esthesiometer. Tear evaluation, corneal sensitivity, and DE symptoms were compared before and after DQS or AT administration. The correlation between the improvement degrees of corneal sensitivity and DE symptoms following medication was analyzed. DQS significantly improved tear BUT and tear meniscus height (TMH) scores (p short tear BUT DE. However, DQS seems to be more effective to adjust tear environment, leading to the normalization of corneal sensitivity and DE symptoms. UMIN Clinical Trials Registry Identifier, UMIN000014536.

[Assessment of lipid layer thickness of tear film in the diagnosis of dry-eye syndrome in children after the hematopoietic stem cell transplantation].

Science.gov (United States)

Kurpińska, Małgorzata; Gorczyńska, Ewa; Owoc-Lempach, Joanna; Bernacka, Aleksandra; Misiuk-Hojło, Marta; Chybicka, Alicja

2011-01-01

Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS) is recognized as the most frequent ocular complication after allogeneic stem cell transplantation (allo-SCT). KCS can appear either due to insufficient tear production or excessive tear evaporation, both resulting in tears hyperosmolarity that leads to ocular damage. The evaporation rate and better film stability is determined primarily by the status of the lipid layer. Observation and classification of tear film lipid layer interference patterns in normal and dry eyes in patients after allogeneic stem cell transplantation with a follow-up time of 6 months-5 years (median 26.54 months). Investigation of the relation between the lipid layer interference patterns in normal and dry eyes and the results of other dry eye examinations and complaints. Relation between DES and conditioning regimes, including total body irradiation and high-dose chemotherapy, immunosuppressive drugs, the time after allogeneic stem cell transplantation and chronic graft-versus-host disease. Precorneal tears lipid layer interference patterns, were examined in 114 eyes in treatment group with the Tearscope-plus. Patient with dry eye were identified on the basis of Schirmer test scores and/or tear breakup time, and positive lissamine and/or fluorescein staining. 42 of 114 eyes (36.8%) developed DES after allo-SCT A significant correlation between thickness of lipid layer and BUT, Schirmer test, lissamine green and fluorescein staining was found in the treatment group. A significant association was found between present chronic GVHD and DES in children. DES was not associated with TBI, corticosteroids, immunosuppressive drugs and the time in the present study. Tears lipid layer interference patterns are highly correlated with the diagnosis of DES. Tears lipid layer interference patterns ( noninvasive method), can be used to diagnose early DES in children after allo-SCT. Chronic GVHD play a major role in development of DES

Behavior of sphingomyelin and ceramide in a tear film lipid layer model

Czech Academy of Sciences Publication Activity Database

Olžyńska, A.; Cwiklik, Lukasz

2017-01-01

Roč. 210, March (2017), s. 128-134 ISSN 0940-9602 Institutional support: RVO:61388963 Keywords : tear film lipid layer * molecular dynamics simulations * Langmuir balance * sphingomyelin * ceramide Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.864, year: 2016

Comparative study on fractal analysis of interferometry images with application to tear film surface quality assessment.

Science.gov (United States)

Szyperski, Piotr D

2018-06-01

The purpose of this research was to evaluate the applicability of the fractal dimension (FD) estimators to assess lateral shearing interferometric (LSI) measurements of tear film surface quality. Retrospective recordings of tear film measured with LSI were used: 69 from healthy subjects and 41 from patients diagnosed with dry eye syndrome. Five surface quality descriptors were considered, four based on FD and a previously reported descriptor operating in a spatial frequency domain (M 2 ), presenting temporal kinetics of post-blink tear film. A set of 12 regression parameters has been extracted and analyzed for classification purposes. The classifiers are assessed in terms of receiver operating characteristics and areas under their curves (AUC). Also, the computational loads are estimated. The maximum AUC of 82.4% was achieved for M 2 , closely followed by the binary box-counting (BBC) FD estimator with AUC=78.6%. For all descriptors, statistically significant differences between the subject groups were found (pfilm kinetics. They provide a viable alternative to previously used spectral counter parameters, and at the same time allow higher computational efficiency.

Calculating electron cyclotron current drive stabilization of resistive tearing modes in a nonlinear magnetohydrodynamic model

International Nuclear Information System (INIS)

Jenkins, Thomas G.; Schnack, Dalton D.; Kruger, Scott E.; Hegna, C. C.; Sovinec, Carl R.

2010-01-01

A model which incorporates the effects of electron cyclotron current drive (ECCD) into the magnetohydrodynamic equations is implemented in the NIMROD code [C. R. Sovinec et al., J. Comput. Phys. 195, 355 (2004)] and used to investigate the effect of ECCD injection on the stability, growth, and dynamical behavior of magnetic islands associated with resistive tearing modes. In addition to qualitatively and quantitatively agreeing with numerical results obtained from the inclusion of localized ECCD deposition in static equilibrium solvers [A. Pletzer and F. W. Perkins, Phys. Plasmas 6, 1589 (1999)], predictions from the model further elaborate the role which rational surface motion plays in these results. The complete suppression of the (2,1) resistive tearing mode by ECCD is demonstrated and the relevant stabilization mechanism is determined. Consequences of the shifting of the mode rational surface in response to the injected current are explored, and the characteristic short-time responses of resistive tearing modes to spatial ECCD alignments which are stabilizing are also noted. We discuss the relevance of this work to the development of more comprehensive predictive models for ECCD-based mitigation and control of neoclassical tearing modes.

Diquafosol Ophthalmic Solution Increases Pre- and Postlens Tear Film During Contact Lens Wear in Rabbit Eyes.

Science.gov (United States)

Nagahara, Yukiko; Koh, Shizuka; Oshita, Yoshihiro; Nagano, Takashi; Mano, Hidetoshi; Nishida, Kohji; Watanabe, Hitoshi

2017-11-01

To investigate the behavior of prelens tear film (PLTF) and postlens tear film (PoLTF) after the instillation of diquafosol using an experimental rabbit model of eyes with contact lens. Cross-sectional, anterior segment optical coherence tomographic images of the inferior midperipheral cornea were obtained at baseline and at 5, 15, 30, 60, 90, and 120 min after the instillation of 3% diquafosol ophthalmic solution in 10 Japanese white rabbits wearing contact lenses. From the obtained images, the areas of the PLTF and PoLTF were calculated. Both artificial tear solution and 0.1% sodium hyaluronate ophthalmic solution were used for comparison. Significant fluid accumulation in both the PLTF and PoLTF was observed after diquafosol instillation, whereas no fluid accumulation was visible after the instillation of artificial tear or sodium hyaluronate. The increase in PLTF area after diquafosol instillation was significantly higher (Pophthalmic solution increases PLTF and PoLTF in rabbit eyes with contact lenses. Diquafosol has potential as a treatment option for contact lens-related dry eye.

Behavior of sphingomyelin and ceramide in a tear film lipid layer model

Czech Academy of Sciences Publication Activity Database

Olžyńska, Agnieszka; Cwiklik, Lukasz

2017-01-01

Roč. 210, MAR 2017 (2017), s. 128-134 ISSN 0940-9602 R&D Projects: GA ČR GA15-14292S Institutional support: RVO:61388955 Keywords : Molecular dynamics simulations * Sphingomyelin * Tear film lipid layer Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.864, year: 2016

A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye

KAUST Repository

Gaffney, E.A.

2010-01-01

Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model for the mass and solute balance of the tears, with parameter estimation based on extensive data from the literature which permits the influence of tear evaporation, lacrimal flux and blink rate on tear osmolarity to be explored. In particular the nature of compensatory events has been estimated in aqueous-deficient (ADDE) and evaporative (EDE) dry eye. The model reproduces observed osmolarities of the tear meniscus for the healthy eye and predicts a higher concentration in the tear film than meniscus in normal and dry eye states. The differential is small in the normal eye, but is significantly increased in dry eye, especially for the simultaneous presence of high meniscus concentration and low meniscus radius. This may influence the interpretation of osmolarity values obtained from meniscus samples since they need not fully reflect potential damage to the ocular surface caused by tear film hyperosmolarity. Interrogation of the model suggests that increases in blink rate may play a limited role in compensating for a rise in tear osmolarity in ADDE but that an increase in lacrimal flux, together with an increase in blink rate, may delay the development of hyperosmolarity in EDE. Nonetheless, it is predicted that tear osmolarity may rise to much higher levels in EDE than ADDE before the onset of tear film breakup, in the absence of events at the ocular surface which would independently compromise tear film stability. Differences in the predicted responses of the pre-ocular tears in ADDE compared to EDE or hybrid disease to defined conditions suggest that no single, empirically-accessible variable can act as a surrogate for tear film concentration and the potential for ocular surface damage. This emphasises the need to measure

A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye.

Science.gov (United States)

Gaffney, E A; Tiffany, J M; Yokoi, N; Bron, A J

2010-01-01

Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model for the mass and solute balance of the tears, with parameter estimation based on extensive data from the literature which permits the influence of tear evaporation, lacrimal flux and blink rate on tear osmolarity to be explored. In particular the nature of compensatory events has been estimated in aqueous-deficient (ADDE) and evaporative (EDE) dry eye. The model reproduces observed osmolarities of the tear meniscus for the healthy eye and predicts a higher concentration in the tear film than meniscus in normal and dry eye states. The differential is small in the normal eye, but is significantly increased in dry eye, especially for the simultaneous presence of high meniscus concentration and low meniscus radius. This may influence the interpretation of osmolarity values obtained from meniscus samples since they need not fully reflect potential damage to the ocular surface caused by tear film hyperosmolarity. Interrogation of the model suggests that increases in blink rate may play a limited role in compensating for a rise in tear osmolarity in ADDE but that an increase in lacrimal flux, together with an increase in blink rate, may delay the development of hyperosmolarity in EDE. Nonetheless, it is predicted that tear osmolarity may rise to much higher levels in EDE than ADDE before the onset of tear film breakup, in the absence of events at the ocular surface which would independently compromise tear film stability. Differences in the predicted responses of the pre-ocular tears in ADDE compared to EDE or hybrid disease to defined conditions suggest that no single, empirically-accessible variable can act as a surrogate for tear film concentration and the potential for ocular surface damage. This emphasises the need to measure

The effect of smoking on the ocular surface and the precorneal tear film

Directory of Open Access Journals (Sweden)

Jyothi Thomas

2012-04-01

Full Text Available BackgroundSmoking, both active and passive, creates a plethora ofhealth‐related problems, which primarily affect thecardiovascular and respiratory systems. There is very littleevidence on the effects of tobacco smoke on the eye,especially regarding anterior ocular surface relatedpathology. This study was undertaken to determine theeffects of smoking on the ocular surface and the tear film insmokers.MethodsA total of 51 (102 eyes smokers and 50 (100 eyes age‐ andgender‐matched healthy non‐smokers were included in thisstudy. The ocular surface was evaluated by measuring tearfilm break‐up time, surface staining with fluorescein, andcorneal and conjunctival sensitivities, and by completing theSchirmer’s II test. Data was analysed using StatisticalPackage for Social Sciences (SPSS version 11.5. A p valueless than 0.05 was considered statistically significant.ResultsThe smoker group had significantly lower tear film break‐uptime, and corneal and conjunctival sensitivity than the nonsmokergroup. Punctate staining was significantly higher inthe smoker group than the non‐smoker group. There wasno statistically significant difference in Schirmer’s II testresults between the smoker and non‐smoker group.ConclusionSmoking caused adverse effects on the precorneal tear filmand there was strong association between smoking and tearfilm instability. Although a causative relationship could notbe determined, there is a need for further longitudinalstudies.

Coupling Fluid and Solute Dynamics Within the Ocular Surface Tear Film: A Modelling Study of Black Line Osmolarity

KAUST Repository

Zubkov, V. S.

2012-07-06

We present a mathematical model describing the spatial distribution of tear film osmolarity across the ocular surface of a human eye during one blink cycle, incorporating detailed fluid and solute dynamics. Based on the lubrication approximation, our model comprises three coupled equations tracking the depth of the aqueous layer of the tear film, the concentration of the polar lipid, and the concentration of physiological salts contained in the aqueous layer. Diffusive boundary layers in the salt concentration occur at the thinnest regions of the tear film, the black lines. Thus, despite large Peclet numbers, diffusion ameliorates osmolarity around the black lines, but nonetheless is insufficient to eliminate the build-up of solute in these regions. More generally, a heterogeneous distribution of solute concentration is predicted across the ocular surface, indicating that measurements of lower meniscus osmolarity are not globally representative, especially in the presence of dry eye. Vertical saccadic eyelid motion can reduce osmolarity at the lower black line, raising the prospect that select eyeball motions more generally can assist in alleviating tear film hyperosmolarity. Finally, our results indicate that measured evaporative rates will induce excessive hyperosmolarity at the black lines, even for the healthy eye. This suggests that further evaporative retardation at the black lines, for instance due to the cellular glycocalyx at the ocular surface or increasing concentrations of mucus, will be important for controlling hyperosmolarity as the black line thins. © 2012 Society for Mathematical Biology.

Adsorption of apo- and holo-tear lipocalin to a bovine Meibomian lipid film.

Science.gov (United States)

Mudgil, Poonam; Millar, Thomas J

2008-04-01

Adsorption of apo- and holo-tear lipocalin (Tlc) to bovine Meibomian lipid film was studied. A Langmuir trough was used for these studies and the adsorption of protein was observed by recording changes in the pressure with time (pi-T profile). The films were photographed at different stages of adsorption by doping Meibomian lipids with a fluorescently tagged lipid. The results indicated that apo-Tlc adsorbed much more quickly than holo-Tlc to the Meibomian lipid film. Contrary to the expectation that holo-Tlc would release lipids to the surface and surface pressure would be higher, it was found that the surface pressure was higher with the adsorption of apo-Tlc to the surface. Photography of the films showed that apo- and holo-Tlc interacted differently with the Meibomian lipid layer. Adsorption of holo-Tlc resulted in big bright patches and adsorption of apo-Tlc resulted in many small patches along with the big patches. Both forms of Tlc produced a more stable film as indicated by decreased movement of the protein adsorbed films, and a higher maximum surface pressure upon compression of these films compared with Meibomian lipid films alone. Isocyles of apo-Tlc adsorbed films gave a higher surface pressure than that of holo-Tlc. From these results, it is concluded that both apo- and holo-Tlc adsorbed to the Meibomian lipid layer and the delivery of the lipids from Tlc to the outer lipid layer could not be detected by our techniques. Its scavenging role to remove lipids from the corneal surface and bind with them might be beneficial for increasing tear viscosity but whether those lipids are delivered to the outermost lipid layer still remains unclear.

The influence of toroidicity, pressure and local profile changes on tearing mode stability

International Nuclear Information System (INIS)

Connor, J.W.; Hastie, R.J.; Martin, T.J.; Cowley, S.C.

1992-01-01

Tearing modes appear to play a significant role in determining Tokamak behaviour. In high temperature plasmas realistic plasma models for the response at the resonant magnetic surfaces necessitate the use of asymptotic matching methods (the Δ' formulation) in calculations of linear stability and non-linear saturation. These calculations are complicated by toroidal and surface shape effects which cause coupling of different poloidal harmonics in a tearing mode. This leads to coupling of tearing modes centred on different resonant surfaces. However, when diamagnetic effects and sheared equilibrium flows are taken into account theory predicts that tearing will occur at only one surface. At all other surfaces the plasma response is determined by the ideal inertial equations. As a first approximation we treat this as infinite, and calculate the scalar Δ' m/n associated with one resonant surface at a time. (author) 8 refs., 2 figs., 2 tabs

Anterior Segment Optical Coherence Tomography for Tear Meniscus Evaluation and its Correlation with other Tear Variables in Healthy Individuals

Science.gov (United States)

Dhasmana, Renu; Nagpal, Ramesh Chander

2016-01-01

Introduction Dry eye is one of the most common ocular diseases in this cyber era. Despite availability of multiple tests, no single test is accurate for the diagnosis of dry eye. Anterior segment optical coherence tomography is the recent tool which can be added in the armentarium of dry eye tests. Aim To evaluate tear meniscus with anterior segment optical coherence tomography and its correlation with other tear variables in normal healthy individuals. Materials and Methods In this prospective cross-sectional observational study, right eye of 203 consecutive patients were studied. All the patients were divided into three groups Group 1, 2 and 3 according to their age ≤20 years, 21-40 years and >40 years respectively. All patients underwent routine ophthalmologic examinations along with slit-lamp bio-microscopy for tear meniscus height measurement, tear film break up time, Schirmer’s I test (with anaesthesia) and optical coherence tomography imaging of inferior tear meniscus height. After focusing of the instrument with a Cross Line (CL) centered on lower tear meniscus at 6’0 clock of cornea, a 6 mm long scan was obtained. The tear meniscus height (μm) and tear meniscus area (mm2) were measured manually with help of callipers by joining upper corneo-meniscus junction to the lower lid-meniscus junction and tear meniscus height and area within the plotted line respectively and calculated by using the integrated analysis available in the custom software. Results There was significant decrease in the all tear variables with the increase in the age. According to age groups in group 1, the mean Schirmer’s (24.0±4.9)mm, tear film break up time (11.1±1.9) sec, tear meniscus height on slit lamp (600.2±167.3)mm were higher but decreased in group 2 (21.5±5.4,10.8±1.4, 597.5±186.3) and group 3 (19.8 ± 5.1, 10.2 ± 1.6, 485.6 ± 157.7) respectively. Schirmer’s test values and tear film break up time were similar in both sexes (p=0.1 and p= 0.9). Tear meniscus

Lipid peroxidation is increased in tears from the elderly.

Science.gov (United States)

Benlloch-Navarro, Soledad; Franco, Ilenia; Sánchez-Vallejo, Violeta; Silvestre, Dolores; Romero, Francisco Javier; Miranda, María

2013-10-01

We describe a procedure in which tears, obtained from Schirmer strips, are used to measure a marker of lipid peroxidation, malondialdehyde (MDA). We also compared the levels of proteins and MDA in tears from two groups of people: young adults (18-30 years old) and elderly adults (65-85 years old), because the data related to total protein concentration of human tears vary widely and because the majority of people over the age of 65 experience some symptoms of dry eyes and this condition has been recognized as an oxidative stress-induced disease. Our results show a significant difference in the protein concentration of the tears taken from the two age categories, younger adults (18-30 years old) and older adults (65-85 years old). Herein, we report for the first time an increase in MDA concentrations determined by HPLC in human tears based on age. It is possible that alterations in the tear lipid layer may lead to an increase in lipid peroxidation. Further studies are needed to understand the nature and function of tear film and stability in order to obtain new methods to analyze tears in patients with different diseases. In this sense, it would be interesting to compare MDA concentration in tears from control subjects and from people with meibomian gland dysfunction. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tear ferning in normal dogs and dogs with keratoconjunctivitis sicca ...

African Journals Online (AJOL)

This study evaluates tear ferning as an ancillary technique for the evaluation of the canine tear film in normal eyes and eyes affected by keratoconjunctivitis sicca (KCS). Thirty dogs with KCS and 50 control dogs with normal tear film were evaluated with a full ophthalmoscopic examination and a Schirmer tear test type 1 ...

Streaming tearing mode

Science.gov (United States)

Shigeta, M.; Sato, T.; Dasgupta, B.

1985-01-01

The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

Nonlinear Diamagnetic Stabilization of Double Tearing Modes in Cylindrical MHD Simulations

Science.gov (United States)

Abbott, Stephen; Germaschewski, Kai

2014-10-01

Double tearing modes (DTMs) may occur in reversed-shear tokamak configurations if two nearby rational surfaces couple and begin reconnecting. During the DTM's nonlinear evolution it can enter an ``explosive'' growth phase leading to complete reconnection, making it a possible driver for off-axis sawtooth crashes. Motivated by similarities between this behavior and that of the m = 1 kink-tearing mode in conventional tokamaks we investigate diamagnetic drifts as a possible DTM stabilization mechanism. We extend our previous linear studies of an m = 2 , n = 1 DTM in cylindrical geometry to the fully nonlinear regime using the MHD code MRC-3D. A pressure gradient similar to observed ITB profiles is used, together with Hall physics, to introduce ω* effects. We find the diamagnetic drifts can have a stabilizing effect on the nonlinear DTM through a combination of large scale differential rotation and mechanisms local to the reconnection layer. MRC-3D is an extended MHD code based on the libMRC computational framework. It supports nonuniform grids in curvilinear coordinates with parallel implicit and explicit time integration.

Tearing-mode stability in a cylindrical plasma with equilibrium flows

International Nuclear Information System (INIS)

Wessen, K.P.; Persson, M.; Australian National Univ., Canberra

1991-01-01

The effect of a sheared equilibrium mass flow on the resistive tearing mode is studied numerically by calculating Δ. Both stabilizing and destabilizing effects are found, depending on the velocity and magnetic field profiles. Specifically, when q o ''varies as'' 1, the flow is strongly stabilizing for centrally peaked current profiles, whereas the flow has a strongly destabilizing effect for flatter current profiles. While the extreme effects are more pronounced for larger flows, a smaller flow may have more influence on marginal stability. The case where the flow speed becomes comparable to the Alfven speed is also examined. It is found that this may lead to the equations being singular at points other than a rational surface, drastically changing the behaviour of the mode. (author)

Neoclassical tearing mode stabilization by ECCD in ITER

International Nuclear Information System (INIS)

Giruzzi, G.; Zabiego, M.

2001-01-01

A dynamic model, based on a 3-D Fokker-Planck code coupled to the island evolution equations, is used to evaluate the feasibility of active control of Neoclassical Tearing modes by Electron Cyclotron Current Drive (ECCD) in International Thermonuclear Experimental Reactor (ITER). The parameters of the present version of ITER, i.e., RTO/RC ITER (IAM option) are used. Both m=3, n=2 and m=2, n=1 modes are considered. It is shown that an Electron Cyclotron wave system at 140 GHz, with toroidally steerable antennas, can stabilize both modes simultaneously if a power ≥30 MW is available

Effect of nonlinear energy transport on neoclassical tearing mode stability in tokamak plasmas

Science.gov (United States)

Fitzpatrick, Richard

2017-05-01

An investigation is made into the effect of the reduction in anomalous perpendicular electron heat transport inside the separatrix of a magnetic island chain associated with a neoclassical tearing mode in a tokamak plasma, due to the flattening of the electron temperature profile in this region, on the overall stability of the mode. The onset of the neoclassical tearing mode is governed by the ratio of the divergences of the parallel and perpendicular electron heat fluxes in the vicinity of the island chain. By increasing the degree of transport reduction, the onset of the mode, as the divergence ratio is gradually increased, can be made more and more abrupt. Eventually, when the degree of transport reduction passes a certain critical value, the onset of the neoclassical tearing mode becomes discontinuous. In other words, when some critical value of the divergence ratio is reached, there is a sudden bifurcation to a branch of neoclassical tearing mode solutions. Moreover, once this bifurcation has been triggered, the divergence ratio must be reduced by a substantial factor to trigger the inverse bifurcation.

Stabilization of tearing modes to suppress major disruptions in tokamaks

International Nuclear Information System (INIS)

Holmes, J.A.; Carreras, B.; Hicks, H.R.; Lynch, S.J.; Waddell, B.V.

1979-02-01

It is shown, for q-profiles which lead to a disruption, that the control of the amplitude of the 2/1 tearing mode avoids the disruption. Q-profiles measured in T-4 and PLT before a major disruption were studied. Two methods of controlling the 2/1 mode amplitude have been considered: (1) Feedback stabilization with the feedback signal locked in phase with the 2/1 mode. (2) Heating slightly outside the q = 2 surface. In both cases it is only necessary to decrease the 2/1 mode amplitude to suppress the disruption. It is not always necessary to stabilize the unstable modes fully

Immediate Effect of 3% Diquafosol Ophthalmic Solution on Tear MUC5AC Concentration and Corneal Wetting Ability in Normal and Experimental Keratoconjunctivitis Sicca Rat Models.

Science.gov (United States)

Choi, Kwang-Eon; Song, Jong-Suk; Kang, Boram; Eom, Youngsub; Kim, Hyo-Myung

2017-05-01

To evaluate the immediate effect of 3% diquafosol ophthalmic solution on tear MUC5AC concentration, periodic acid-Schiff (PAS)-positive goblet cells, and tear film stability in normal and keratoconjunctivitis sicca (KCS) rat models. Rats were divided into normal and KCS groups. 3% of diquafosol solution was instilled into the right eye and normal saline into the left eye in both groups. To determine the peak time of tear MUC5AC concentration, tears were collected after 3% diquafosol instillation every 5 min up to 20 min. The tear film stability and the numbers of PAS-positive goblet cells were compared in both models. After diquafosol instillation, tear MUC5AC concentration increased steadily for 15 min, at which point the MUC5AC concentration reached its peak. In both normal and KCS groups, the MUC5AC concentration at 15 min was higher after instillation of 3% diquafosol solution (17.77 ± 2.09 ng/ml in the normal group, 9.65 ± 3.51 ng/ml in the KCS group) than that after saline instillation (13.74 ± 2.87 ng/ml in the normal group, 8.19 ± 3.99 ng/ml in the KCS group) (p = 0.018 for both). The corneal wetting ability was significantly longer after instillation of 3% diquafosol solution compared with that after instillation of normal saline in the normal group (p = 0.018). The percentage of PAS-positive goblet cells after the instillation of 3% diquafosol solution was significantly lower than that after instillation of normal saline in both models (p = 0.018 for both). Diquafosol ophthalmic solution was effective in stimulating mucin secretion in both normal and KCS rat models, and the peak time of tear MUC5AC concentration was 15 min after diquafosol instillation. The increased tear MUC5AC concentration was accompanied by improved tear film stability and a decreased percentage of PAS-positive goblet cells.

Poly(lactic acid (PLA Based Tear Resistant and Biodegradable Flexible Films by Blown Film Extrusion

Directory of Open Access Journals (Sweden)

Norma Mallegni

2018-01-01

Full Text Available Poly(lactic acid (PLA was melt mixed in a laboratory extruder with poly(butylene adipate-co-terephthalate (PBAT and poly(butylene succinate (PBS in the presence of polypropylene glycol di glycidyl ether (EJ400 that acted as both plasticizer and compatibilizer. The process was then scaled up in a semi-industrial extruder preparing pellets having different content of a nucleating agent (LAK. All of the formulations could be processed by blowing extrusion and the obtained films showed mechanical properties dependent on the LAK content. In particular the tearing strength showed a maximum like trend in the investigated composition range. The films prepared with both kinds of blends showed a tensile strength in the range 12–24 MPa, an elongation at break in the range 150–260% and a significant crystallinity.

Tearing mode instability due to anomalous resistivity

International Nuclear Information System (INIS)

Furuya, Atsushi; Itoh, Sanae I.; Yagi, Masatoshi

2000-01-01

Tearing mode instability in the presence of microscopic truculence is investigates. The effects of microscopic turbulence on tearing mode are taken as drags which are calculated by one-point renormalization method and mean-field approximation. These effects are reduced to effective diffusivities in reduced MHD equations. Using these equations, the stability analyses of the tearing mode are performed. It is shown that a finite amplitude of fluctuation enhances the growth rate of tearing mode. For very high values of turbulent diffusivities, marginally stable state exists. The effects of each turbulent diffusivity on mode stability are examined near marginal stability boundary. Parameter dependence of the resistive ballooning mode turbulence on tearing mode is analyzed as an example. (author)

A theorem for non-linear stability to tearing modes

International Nuclear Information System (INIS)

Avinash, K.

1992-12-01

Within the reduced MHD approximation it is shown that dJ z /dΨ≤0 [J z is z component of the current density and Ψ is the helical flux] is a sufficient condition for the equilibrium to be non-linearly stable to tearing mode. It is further shown that this is also a sufficient condition for an equilibrium to be axisymmetric, hence helical equilibrium consistent with this condition cannot be constructed. However a class of axisymmetric equilibrium with hollow current profile is shown to satisfy the stability criterion. (author). 16 refs, 2 figs

Tearing-mode stability of a forming Spheromak plasma

International Nuclear Information System (INIS)

Heidbrink, W.W.; Jardin, S.C.; Chance, M.S.

1981-10-01

The results of numerical calculations of Δ' for a class of equilibria typical of those encountered during the early formation stage of the S1 Spheromak are presented. The equilibrium plasma is assumed to be cylindrically symmetric and pressureless. It encloses a current carrying perfect conductor (flux core) and is surrounded by a vacuum with zero longitudinal field. Stability boundaries in the space formed by the equilibrium parameters are mapped. The plasma is tearing mode stable provided B/sub z//B/sub theta/ at the flux core is below a certain critical value which depends on the equilibrium parameters. For typical equilibria, this critical value is 0.65

Nonlinear drift tearing mode. Strong mode of excitation and stabilization mechanisms

International Nuclear Information System (INIS)

Galeev, A.A.; Zelenyj, L.M.; Kuznetsova, M.M.

1985-01-01

A nonlinear theory of magnetic disturbance development in collisionless configurations with magnetic field shear is considered. The instability evolution is investigated with account for the dynamics of ions and potential electric fields which determine the mode stabilization. It has been found that the drift tearing mode possesses metastable properties: in a nonlinear mode even the growth of linearly stable disturbances of the finite amplitude is possible

Tearing modes in toroidal geometry

International Nuclear Information System (INIS)

Connor, J.W.; Cowley, S.C.; Hastie, R.J.; Hender, T.C.; Hood, A.; Martin, T.J.

1988-01-01

The separation of the cylindrical tearing mode stability problem into a resistive resonant layer calculation and an external marginal ideal magnetohydrodynamic (MHD) calculation (Δ' calculation) is generalized to axisymmetric toroidal geometry. The general structure of this separation is analyzed and the marginal ideal MHD information (the toroidal generalization of Δ') required to discuss stability is isolated. This can then, in principle, be combined with relevant resonant layer calculations to determine tearing mode growth rates in realistic situations. Two examples are given: the first is an analytic treatment of toroidally coupled (m = 1, n = 1) and (m = 2, n = 1) tearing modes in a large aspect ratio torus; the second, a numerical treatment of the toroidal coupling of three tearing modes through finite pressure effects in a large aspect ratio torus. In addition, the use of a coupling integral approach for determining the stability of coupled tearing modes is discussed. Finally, the possibility of using initial value resistive MHD codes in realistic toroidal geometry to determine the necessary information from the ideal MHD marginal solution is discussed

Dysfunctional tear syndrome: dry eye disease and associated tear film disorders - new strategies for diagnosis and treatment.

Science.gov (United States)

Milner, Mark S; Beckman, Kenneth A; Luchs, Jodi I; Allen, Quentin B; Awdeh, Richard M; Berdahl, John; Boland, Thomas S; Buznego, Carlos; Gira, Joseph P; Goldberg, Damien F; Goldman, David; Goyal, Raj K; Jackson, Mitchell A; Katz, James; Kim, Terry; Majmudar, Parag A; Malhotra, Ranjan P; McDonald, Marguerite B; Rajpal, Rajesh K; Raviv, Tal; Rowen, Sheri; Shamie, Neda; Solomon, Jonathan D; Stonecipher, Karl; Tauber, Shachar; Trattler, William; Walter, Keith A; Waring, George O; Weinstock, Robert J; Wiley, William F; Yeu, Elizabeth

2017-01-01

Dysfunctional tear syndrome (DTS) is a common and complex condition affecting the ocular surface. The health and normal functioning of the ocular surface is dependent on a stable and sufficient tear film. Clinician awareness of conditions affecting the ocular surface has increased in recent years because of expanded research and the publication of diagnosis and treatment guidelines pertaining to disorders resulting in DTS, including the Delphi panel treatment recommendations for DTS (2006), the International Dry Eye Workshop (DEWS) (2007), the Meibomian Gland Dysfunction (MGD) Workshop (2011), and the updated Preferred Practice Pattern guidelines from the American Academy of Ophthalmology pertaining to dry eye and blepharitis (2013). Since the publication of the existing guidelines, new diagnostic techniques and treatment options that provide an opportunity for better management of patients have become available. Clinicians are now able to access a wealth of information that can help them obtain a differential diagnosis and treatment approach for patients presenting with DTS. This review provides a practical and directed approach to the diagnosis and treatment of patients with DTS, emphasizing treatment that is tailored to the specific disease subtype as well as the severity of the condition.

Relationship of Corneal Pain Sensitivity With Dry Eye Symptoms in Dry Eye With Short Tear Break-Up Time.

Science.gov (United States)

Kaido, Minako; Kawashima, Motoko; Ishida, Reiko; Tsubota, Kazuo

2016-03-01

The purpose of this prospective comparative study was to investigate corneal sensitivity in subjects with unstable tear film, with and without dry eye (DE) symptoms. Forty-one eyes of 41 volunteers (mean age: 45.1 ± 9.4 years; age range, 23-57 years), with normal tear function and ocular surface except for tear stability, were studied. The eyes were divided into two groups depending on the presence or absence of DE symptoms: 21 eyes with DE symptoms (symptomatic group); and 20 eyes without DE symptoms (asymptomatic group). Three types of corneal sensitivity values were measured using a Cochet-Bonnet esthesiometer: the sensitivity for perception of touch (S-touch), the sensitivity for blinking (S-blink), and the sensitivity for pain (S-pain). Mean S-blink and S-pain were significantly higher in the symptomatic group than in the asymptomatic group (P 0.05). Corneal sensitivity for blinking and pain evoked by increased stimuli was higher in the symptomatic group (subjects with short break-up time DE) compared with subjects who have no DE symptoms despite decreased tear stability. The presence of both tear instability and hyperesthesia, rather than tear instability alone, may contribute to DE pathogenesis.

[Alterations in tears aqueous layer during cytostatics treatment].

Science.gov (United States)

Wojciechowska, Katarzyna; Wieckowska-Szakiel, Marzena; Rózalska, Barbara; Jurowski, Piotr

2013-01-01

The aim of the study was to evaluate tears secretion, pH and lysozyme activity in tears aqueous layer during chemotherapy in lung, breast and bowel cancer. 36 patients were enrolled to the study. Depending on the type of cancer and type of chemotherapy patients were divided into three groups. Group I (12 patients) diagnosed with non-small-cell lung cancer treated with PE schema (cisplatin, etoposide), Group II (12 patients) with breast cancer treated with FAC schema (fluorouracil, doxorubicin, cyclophosphamide), Group III (12 patients) with bowel cancer treated with FU/LV schema (fluorouracil, leucovorin). In all the patients: Schirmer's I test, pH measurements and lysozyme test were performed. Patients were examined before chemotherapy, after 2nd, 4th, 6th cycle. In group I and II lowering of tears secretion (p tears secretion (p tears film in all groups (p tears aqueous layer causing alterations of tears secretions. PH alterations depending on type of chemotherapy was observed. Lowering of lysozyme activity in tears was observed. All the deteriorations aggravate with duration of chemotherapy. Alterations of tears film parameters during chemotherapy may influence upon eye surface homeostasis and infectious complication. tears aqueous layer, Schirmer's test, lysozyme activity, tears pH.

Global existence of solutions to a tear film model with locally elevated evaporation rates

Science.gov (United States)

Gao, Yuan; Ji, Hangjie; Liu, Jian-Guo; Witelski, Thomas P.

2017-07-01

Motivated by a model proposed by Peng et al. (2014) for break-up of tear films on human eyes, we study the dynamics of a generalized thin film model. The governing equations form a fourth-order coupled system of nonlinear parabolic PDEs for the film thickness and salt concentration subject to non-conservative effects representing evaporation. We analytically prove the global existence of solutions to this model with mobility exponents in several different ranges and present numerical simulations that are in agreement with the analytic results. We also numerically capture other interesting dynamics of the model, including finite-time rupture-shock phenomenon due to the instabilities caused by locally elevated evaporation rates, convergence to equilibrium and infinite-time thinning.

Tears of Wine

Science.gov (United States)

Gugliotti, Marcos

2004-01-01

The unique occurrence of the upward motion of a thin film of wine, and its formation into drops inside the wall of a wine glass is explained. Evaporation of alcohol generates a surface tension gradient, moving the film of wine upwards on the internal sides of a wine glass, where it collects and forms into drops or tears.

Sebum/Meibum Surface Film Interactions and Phase Transitional Differences.

Science.gov (United States)

Mudgil, Poonam; Borchman, Douglas; Gerlach, Dylan; Yappert, Marta C

2016-05-01

Sebum may contribute to the composition of the tear film lipid layer naturally or as a contaminant artifact from collection. The aims of this study were to determine: if sebum changes the rheology of meibum surface films; if the resonance near 5.2 ppm in the 1H-NMR spectra of sebum is due to squalene (SQ); and if sebum or SQ, a major component of sebum, interacts with human meibum. Human meibum was collected from the lid margin with a platinum spatula. Human sebum was collected using lipid absorbent tape. Langmuir trough technology was used to measure the rheology of surface films. Infrared spectroscopy was used to measure lipid conformation and phase transitions. We used 1H-NMR to measure composition and confirm the primary structure of SQ. The NMR resonance near 5.2 ppm in the spectra of human sebum was from SQ which composed 28 mole percent of sebum. Both sebum and SQ lowered the lipid order of meibum. Sebum expanded meibum films at lower concentrations and condensed meibum films at higher concentrations. Sebum caused meibum to be more stable at higher pressures (greater maximum surface pressure). Physiological levels of sebum would be expected to expand or fluidize meibum making it spread better and be more surface active (qualities beneficial for tear film stability). Sebum would also be expected to stabilize the tear film lipid layer, which may allow it to withstand the high shear pressure of a blink.

Effects of Systane® Balance on noninvasive tear film break-up time in patients with lipid-deficient dry eye

Directory of Open Access Journals (Sweden)

Aguilar AJ

2014-11-01

Full Text Available Alejandro J Aguilar, Maria I Marquez, Paula A Albera, Jorge L Tredicce, Alejandro Berra Universidad de Buenos Aires, Buenos Aires, Argentina Purpose: To evaluate the ability of Systane® Balance (SYSB administered four times per day for 4 weeks to increase noninvasive tear film break-up time (NITFBUT over baseline compared with a saline (SAL control in patients with lipid-deficient dry eye (DE.Patients and methods: Patients aged ≥18 years with DE and evidence of meibomian gland dysfunction (ie, abnormal gland expression and missing meibomian glands were included in this randomized, parallel-group, controlled, investigator-masked comparison study. Patients were randomized to SYSB or SAL four times daily for 4 weeks. The primary efficacy variable was mean change in NITFBUT from baseline at week 4. Ocular surface staining, goblet cell density, and meibomian gland expression were also assessed. Safety assessments included adverse events (AEs, best-corrected visual acuity, and ocular signs.Results: A total of 49 patients received study treatments (SYSB, n=25; SAL, n=24. Most patients were women (67.4% and Caucasian (63.3%; mean ± standard deviation (SD age was 44±19 years. DE characteristics at baseline were similar between groups. After 4 weeks of treatment, the mean ± SD NITFBUT increase from baseline was significantly greater with SYSB (2.83±0.74 seconds compared with SAL (0.66±0.55 seconds; P<0.001, t-test. Improvements in conjunctival and corneal staining, percentage of patients with increased goblet cell density, and meibomian gland expression were also observed with 4 weeks of SYSB over SAL. No AEs were reported for either treatment group; best-corrected visual acuity and ocular signs remained stable or improved compared with baseline.Conclusion: SYSB restored tear film stability, improved ocular surface healing, and improved meibomian gland functionality after 4 weeks of use in patients with lipid-deficient DE. No AEs were reported

Dysfunctional tear syndrome: dry eye disease and associated tear film disorders – new strategies for diagnosis and treatment

Science.gov (United States)

Milner, Mark S.; Beckman, Kenneth A.; Luchs, Jodi I.; Allen, Quentin B.; Awdeh, Richard M.; Berdahl, John; Boland, Thomas S.; Buznego, Carlos; Gira, Joseph P.; Goldberg, Damien F.; Goldman, David; Goyal, Raj K.; Jackson, Mitchell A.; Katz, James; Kim, Terry; Majmudar, Parag A.; Malhotra, Ranjan P.; McDonald, Marguerite B.; Rajpal, Rajesh K.; Raviv, Tal; Rowen, Sheri; Shamie, Neda; Solomon, Jonathan D.; Stonecipher, Karl; Tauber, Shachar; Trattler, William; Walter, Keith A.; Waring, George O.; Weinstock, Robert J.; Wiley, William F.; Yeu, Elizabeth

2017-01-01

Dysfunctional tear syndrome (DTS) is a common and complex condition affecting the ocular surface. The health and normal functioning of the ocular surface is dependent on a stable and sufficient tear film. Clinician awareness of conditions affecting the ocular surface has increased in recent years because of expanded research and the publication of diagnosis and treatment guidelines pertaining to disorders resulting in DTS, including the Delphi panel treatment recommendations for DTS (2006), the International Dry Eye Workshop (DEWS) (2007), the Meibomian Gland Dysfunction (MGD) Workshop (2011), and the updated Preferred Practice Pattern guidelines from the American Academy of Ophthalmology pertaining to dry eye and blepharitis (2013). Since the publication of the existing guidelines, new diagnostic techniques and treatment options that provide an opportunity for better management of patients have become available. Clinicians are now able to access a wealth of information that can help them obtain a differential diagnosis and treatment approach for patients presenting with DTS. This review provides a practical and directed approach to the diagnosis and treatment of patients with DTS, emphasizing treatment that is tailored to the specific disease subtype as well as the severity of the condition. PMID:28099212

Tear function and ocular surface after Muller muscle-conjunctival resection.

Science.gov (United States)

Uğurbaş, Suat Hayri; Alpay, Atilla; Bahadır, Burak; Uğurbaş, Sılay Cantürk

2014-05-01

Muller muscle-conjunctival resection (MCR) is a surgical technique to correct mild and moderate ptosis. In this study, tear function tests and ocular surface are evaluated in patients who underwent unilateral surgery. Sixteen patients with normal preoperative tear function who underwent unilateral MCR were evaluated prospectively. The fellow eyes of the patients were taken as the control group. A dry eye assessment questionnaire, Schirmer testing, tear film break-up time, fluorescein stain, Rose-Bengal stain, and conjunctival impression cytology were used to assess the tear film functions and ocular surface changes in the operated and non-operated eyes. There was no statistically significant difference in the tear function tests and goblet cell densities between the operated and non-operated eyes. The results indicate that an MCR procedure has no apparent effect on tear function tests and goblet cell density in patients with normal preoperative tear function.

Ocular surface and tear film status among contact lens wearers and non-wearers who use VDT at work: comparing three different lens types.

Science.gov (United States)

Tauste, Ana; Ronda, Elena; Baste, Valborg; Bråtveit, Magne; Moen, Bente E; Seguí Crespo, María-Del-Mar

2018-04-01

To analyze differences in the ocular surface appearance and tear film status of contact lens wearers and non-wearers in a group of visual display terminals (VDT) workers and additionally to assess differences between lens materials. Cross-sectional study of 236 office workers, of whom 92 were contact lens wearers. Workers provided information on their contact lenses (conventional hydrogel, silicone hydrogel or rigid gas permeable lenses) and exposure to VDT at work. Ocular surface and tear film status were determined by the presence of bulbar, limbal and lid redness, lid roughness and corneal staining type, and by Schirmer's and tear break-up time tests (TBUT). A generalized linear model was used to calculate the crude (cRR) and age- and sex-adjusted (aRR) relative risk to measure the association between ocular surface and tear film abnormalities and contact lens use and type. The aRR of ocular surface abnormalities was higher in contact lens wearers compared to non-wearers: bulbar redness (aRR 1.69; 95% CI 1.25-2.30), limbal redness (aRR 2.87; 1.88-4.37), lid redness (aRR 2.53; 1.35-4.73) and lid roughness (aRR 7.03; 1.31-37.82). VDT exposure > 4 h/day increased wearers' risk of limbal and lid redness. Conventional hydrogel wearers had the highest risk of ocular surface abnormalities, followed by silicone hydrogel wearers. Both contact and non-contact lens wearers had a high prevalence of altered TBUT (77.3 and 75.7% respectively) and Schirmer (51.8 and 41.3%). Regular contact lens use during VDT exposure at work increases risk of bulbar, limbal and lid redness, and lid roughness, especially in soft contact lens wearers. The high prevalence of altered TBUT and Schirmer's results in all participants suggests that VDT use greatly affects tear film characteristics.

Sebum/Meibum Surface Film Interactions and Phase Transitional Differences

Science.gov (United States)

Mudgil, Poonam; Borchman, Douglas; Gerlach, Dylan; Yappert, Marta C.

2016-01-01

Purpose Sebum may contribute to the composition of the tear film lipid layer naturally or as a contaminant artifact from collection. The aims of this study were to determine: if sebum changes the rheology of meibum surface films; if the resonance near 5.2 ppm in the 1H-NMR spectra of sebum is due to squalene (SQ); and if sebum or SQ, a major component of sebum, interacts with human meibum. Methods Human meibum was collected from the lid margin with a platinum spatula. Human sebum was collected using lipid absorbent tape. Langmuir trough technology was used to measure the rheology of surface films. Infrared spectroscopy was used to measure lipid conformation and phase transitions. We used 1H-NMR to measure composition and confirm the primary structure of SQ. Results The NMR resonance near 5.2 ppm in the spectra of human sebum was from SQ which composed 28 mole percent of sebum. Both sebum and SQ lowered the lipid order of meibum. Sebum expanded meibum films at lower concentrations and condensed meibum films at higher concentrations. Sebum caused meibum to be more stable at higher pressures (greater maximum surface pressure). Conclusions Physiological levels of sebum would be expected to expand or fluidize meibum making it spread better and be more surface active (qualities beneficial for tear film stability). Sebum would also be expected to stabilize the tear film lipid layer, which may allow it to withstand the high shear pressure of a blink. PMID:27145473

The influence of non-polar lipids on tear film dynamics

KAUST Repository

Bruna, M.

2014-04-04

© 2014 Cambridge University Press. In this paper we examine the effect that physiological non-polar lipids, residing on the surface of an aqueous tear film, have on the film evolution. In our model we track the evolution of the thickness of the non-polar lipid layer, the thickness of the aqueous layer and the concentration of polar lipids which reside at the interface between the two. We also utilise a force balance in the non-polar lipid layer in order to determine its velocity. We show how to obtain previous models in the literature from our model by making particular choices of the parameters. We see the formation of boundary layers in some of these submodels, across which the concentration of polar lipid and the non-polar lipid velocity and film thickness vary. We solve our model numerically for physically realistic parameter values, and we find that the evolution of the aqueous layer and the polar lipid layer are similar to that described by previous authors. However, there are interesting dynamics for the non-polar lipid layer. The effects of altering the key parameters are highlighted and discussed. In particular, we see that the Marangoni number plays a key role in determining how far over the eye the non-polar lipid spreads.

Tearing mode analysis in tokamaks, revisited

International Nuclear Information System (INIS)

Nishimura, Y.; Callen, J.D.; Hegna, C.C.

1997-12-01

A new Δ' shooting code has been developed to investigate tokamak plasma tearing mode stability in a cylinder and large aspect ratio (ε ≤ 0.25) toroidal geometries, neglecting toroidal mode coupling. A different computational algorithm is used (shooting out from the singular surface instead of into it) to resolve the strong singularities at the mode rational surface, particularly in the presence of finite pressure term. Numerical results compare favorably with Furth et al. results. The effects of finite pressure, which are shown to decrease Δ', are discussed. It is shown that the distortion of the flux surfaces by the Shafranov shift, which modifies the geometry metric element stabilizes the tearing mode significantly, even in a low β regime before the toroidal magnetic curvature effects come into play. Double tearing modes in toroidal geometries are examined as well. Furthermore, m ≥ 2 tearing mode stability criteria are compared with three dimensional initial value MHD simulation by the FAR code

Tear clearance implications for ocular surface health.

Science.gov (United States)

de Paiva, Cintia Sade; Pflugfelder, Stephen C

2004-03-01

Tear clearance/turnover provides a global assessment of the function of the lacrimal functional unit and of tear exchange on the ocular surface. It is an indirect measure of dry eye induced inflammation on the ocular surface. It shows better correlation with the severity of ocular irritation symptoms and corneal epithelial disease in dry eye than the Schirmer 1 test. Delayed tear clearance may prove to be the best measure for identifying patients with tear film disorders who may respond to anti-inflammatory therapy.

Stability and magnetic tearing of finite-β modified drift waves

International Nuclear Information System (INIS)

Chen, L.; Hsu, J.; Kaw, P.K.; Rutherford, P.H.

1977-10-01

A new simplified approach to the analysis of radial eigenmodes of finite-β modified drift waves in a sheared magnetic field is described. Applying this approach to the universal drift mode, one recovers, for the lowest (n = 0) radial eigenmode, the previous result that finite-β effects are stabilizing. For the next (n = 1) radial eigenmode, however, one finds that finite-β effects further destabilize the mode. Moreover, the corresponding mode structure exhibits nonzero radial (tearing) magnetic perturbations around the mode-rational surface. The consequences of a structure of microscopic magnetic islands, created in this way, for plasma transport are also briefly discussed

Effect of Omega-3 Fatty Acids Dietary Supplementation on Ocular Surface and Tear Film in Diabetic Patients with Dry Eye.

Science.gov (United States)

Georgakopoulos, Constantine D; Makri, Olga E; Pagoulatos, Dionisios; Vasilakis, Panagiotis; Peristeropoulou, Politimi; Kouli, Vasiliki; Eliopoulou, Maria I; Psachoulia, Caterina

2017-01-01

The objective of this study was to investigate the effect of dietary supplementation with omega-3 fatty acids on ocular surface and tear film in patients with type 2 diabetes suffering from dry eye. Thirty-six patients suffering from type 2 diabetes and moderate to severe dry eye syndrome were included in the study. Patients were assigned to receive omega-3 long-chain polyunsaturated fatty acids for 3 months. Tear film break-up time test, Schirmer-I test, and conjunctival impression cytology analysis were performed on all patients at baseline and after 1 and 3 months. The subjective symptoms of dry eye were evaluated with the Ocular Surface Disease Index (OSDI) questionnaire at the same time points. Patients' average age was 65.57 ± 4.27 years and the mean duration of diabetes was 14.85 ± 5.4 years. There was a statistically significant increase in Schirmer-I test results and tear break-up time score after 3 months of supplementary intake of omega-3 fatty acids compared to baseline (p dry eye syndrome in patients with type 2 diabetes.

High melt strength, tear resistant blown film based on poly(lactic acid)

Science.gov (United States)

Edmonds, Neil R.; Plimmer, Peter N.; Tanner, Chris

2015-05-01

A major problem associated with the commercial manufacture of thin films from PLA is inferior processing characteristics on blown film lines compared to low density polyethylene. PLA has poor melt strength (leading to bubble instability) and develops a permanent crease in the flattened film as it exits the tower of the film line. In addition, the thin film product has poor tear strength and an unacceptable `noise' level when converted into flexible packaging. Furthermore, fabricated articles based on PLA are known to show an unattractive tendency toward dimensional instability. This behaviour is associated with `cold crystallization', a phenomenon which also causes exudation of any plasticizer added for improving flexibility. Blow moulded articles based on PLA also exhibit dimensional sensitivity above 60°C. All of these issues have been overcome by the technology described in this paper. This has been accomplished without loss of the valuable compostability characteristic of PLA; this was confirmed by evaluation of film in a commercial composting operation. These results have been achieved through novel reactive compounding technology which: (a) Creates a PLA-rich structure containing long chain crosslinks, (b) generates a low glass transition temperature phase covalently bonded to the PLA structure, and (c) provides a material which performs like LDPE in a blown film manufacturing operation. The technology developed is covered by NZ Patent 580231 (3). The patent is held by UniServices Ltd, The University of Auckland, New Zealand.

Assessment of tear film osmolarity using the TearLab™ osmometer in normal dogs and dogs with keratoconjunctivitis sicca.

Science.gov (United States)

Sebbag, Lionel; Park, Shin Ae; Kass, Philip H; Maggs, David J; Attar, Mayssa; Murphy, Christopher J

2017-07-01

To evaluate repeatability and reproducibility of tear osmolarity measured using the TearLab ™ osmometer in normal dogs and to assess its diagnostic potential in dogs with keratoconjunctivitis sicca (KCS). Beagle dogs; six normal and five with KCS. Tear osmolarity and Schirmer tear test-1 (STT-1) values were obtained at various times. Normal dogs were assessed for diurnal variation and repeatability and reproducibility of measurements. Dogs with KCS were evaluated before and after 5 months' topical twice-daily therapy with 2% cyclosporine. Mean ± SD tear osmolarity (mOsm/L) was significantly higher in normal dogs (337.4 ± 16.2) than in dogs with KCS before therapy (306.2 ± 18.0; P dogs, tear osmolarity readings were stable during the daytime (P = 0.99). Repeated measurements revealed high variability and typically poor-to-moderate repeatability and reproducibility, although this was improved by taking three successive measurements at each session. Considering combined data from all dogs, a positive correlation existed between STT-1 and tear osmolarity measurements (Pearson's correlation test, P = 0.04, r = 0.62). Canine tear osmolarity as determined by TearLab ™ osmometer was variable, required multiple readings to be informative, and differed from values reported for humans. Dogs with KCS had a lower tear osmolarity than did normal dogs, and this increased following cyclosporine therapy. © 2016 American College of Veterinary Ophthalmologists.

Effects of topical cyclosporine a plus artificial tears versus artificial tears treatment on conjunctival goblet cell density in dysfunctional tear syndrome.

Science.gov (United States)

Demiryay, Elvan; Yaylali, Volkan; Cetin, Ebru Nevin; Yildirim, Cem

2011-09-01

The aim was to compare the effects of topical cyclosporine A and artificial tears combination with artificial tears alone in patients with dysfunctional tear syndrome (DTS). Forty-two eyes of 42 patients with DTS were enrolled in the study. The inclusion criteria for the study were Schirmer I (without anesthesia) scores below 10 mm/5 min and tear film break-up time (BUT) below 10 sec. The patients were randomly divided into two groups. The study group (22 patients) underwent 0.05% cyclosporine A treatment twice a day and preservative-free artificial tears for four times a day for 4 months. The control group (20 patients) was administered only preservative-free artificial tears four times a day for 4 months. The BUT, Schirmer test scores, corneal fluorescein staining, conjunctival lissamine green staining, and goblet cell density derived by impression cytology were recorded before and after treatment in each group. In the study group, all parameters improved statistically significantly after treatment at the 4-month follow-up compared with the pretreatment values (Ptears treatment significantly increases goblet cell density, decreases the signs of DTS, and improves ocular surface health.

Stability of fortified cefazolin ophthalmic solutions prepared in artificial tears containing surfactant-based versus oxidant-based preservatives.

Science.gov (United States)

Rojanarata, Theerasak; Tankul, Junlathip; Woranaipinich, Chayanee; Potawanich, Paweena; Plianwong, Samarwadee; Sakulma, Sirinart; Saehuan, Choedchai

2010-10-01

The aim of this study was to investigate the stability of fortified cefazolin sodium ophthalmic solutions (50 mg mL⁻¹) extemporaneously prepared in commercial artificial tears containing 2 different types of preservatives, namely the surfactants and oxidants. Fortified cefazolin sodium solutions were prepared by reconstituting cefazolin for injection with sterile water and further diluted with Tears Naturale II or Natear, 2 commercial artificial tears containing polyquaternium-1 and sodium perborate, respectively, as preservatives. The solutions were then kept at room temperature (28°C) or in the refrigerator (4°C). During the 28-day period, the formulations were periodically examined for the physical appearance, pH, and the remaining drug concentrations. The antibacterial potency was evaluated as the minimal inhibitory concentration against Staphylococcus aureus strain ATCC 29923 by broth dilution technique. The activity of the preservatives was demonstrated by antimicrobial effectiveness tests. On day 28, the microbial contamination in the preparations was tested. The stability profiles of cefazolin solutions prepared in Tears Naturale II, Natear, and water were not different, but they were significantly influenced by the storage temperature. The refrigerated formulations showed no loss of drug and antibacterial potency as well as alteration of physical appearance and pH throughout the 28 days. In contrast, those kept at room temperature showed gradual change in color and odor. The degradation of drug exceeded 10% from day 3 and the decrease of antibacterial potency could be observed at week 3. All cefazolin solutions prepared in artificial tears retained the antimicrobial activity of preservatives and were free from bacterial and fungal contamination throughout the 28-day period of study. Cefazolin sodium ophthalmic solutions can be extemporaneously prepared in Tears Naturale II or Natear without the influence from different types of preservatives used in

Dynamic modelling of tearing mode stabilization by RF current drive

International Nuclear Information System (INIS)

Giruzzi, G.; Zabiego, M.; Gianakon, T.A.; Garbet, X.; Bernabei, S.

1998-01-01

The theory of tearing mode stabilization in toroidal plasmas by RF-driven currents that are modulated in phase with the island rotation is investigated. A time scale analysis of the phenomena involved indicates that transient effects, such as finite time response of the driven currents, island rotation during the power pulses, and the inductive response of the plasma, are intrinsically important. A dynamic model of such effects is developed, based on a 3-D Fokker-Planck code coupled to both the electric field diffusion and the island evolution equations. Extensive applications to both Electron Cyclotron and Lower Hybrid current drive in ITER are presented. (author)

Influence of toroidal rotation on tearing modes

Science.gov (United States)

Cai, Huishan; Cao, Jintao; Li, Ding

2017-10-01

Tearing modes stability analysis including toroidal rotation is studied. It is found that rotation affects the stability of tearing modes mainly through the interaction with resistive inner region of tearing mode. The coupling of magnetic curvature with centrifugal force and Coriolis force provides a perturbed perpendicular current, and a return parallel current is induced to affect the stability of tearing modes. Toroidal rotation plays a stable role, which depends on the magnitude of Mach number and adiabatic index Γ, and is independent on the direction of toroidal rotation. For Γ >1, the scaling of growth rate is changed for typical Mach number in present tokamaks. For Γ = 1 , the scaling keeps unchanged, and the effect of toroidal rotation is much less significant, compared with that for Γ >1. National Magnetic Confinement Fusion Science Program and National Science Foundation of China under Grants No. 2014GB106004, No. 2013GB111000, No. 11375189, No. 11075161 and No. 11275260, and Youth Innovation Promotion Association CAS.

Effects of Systane(®) Balance on noninvasive tear film break-up time in patients with lipid-deficient dry eye.

Science.gov (United States)

Aguilar, Alejandro J; Marquez, Maria I; Albera, Paula A; Tredicce, Jorge L; Berra, Alejandro

2014-01-01

To evaluate the ability of Systane(®) Balance (SYSB) administered four times per day for 4 weeks to increase noninvasive tear film break-up time (NITFBUT) over baseline compared with a saline (SAL) control in patients with lipid-deficient dry eye (DE). Patients aged ≥18 years with DE and evidence of meibomian gland dysfunction (ie, abnormal gland expression and missing meibomian glands) were included in this randomized, parallel-group, controlled, investigator-masked comparison study. Patients were randomized to SYSB or SAL four times daily for 4 weeks. The primary efficacy variable was mean change in NITFBUT from baseline at week 4. Ocular surface staining, goblet cell density, and meibomian gland expression were also assessed. Safety assessments included adverse events (AEs), best-corrected visual acuity, and ocular signs. A total of 49 patients received study treatments (SYSB, n=25; SAL, n=24). Most patients were women (67.4%) and Caucasian (63.3%); mean ± standard deviation (SD) age was 44±19 years. DE characteristics at baseline were similar between groups. After 4 weeks of treatment, the mean ± SD NITFBUT increase from baseline was significantly greater with SYSB (2.83±0.74 seconds) compared with SAL (0.66±0.55 seconds; P<0.001, t-test). Improvements in conjunctival and corneal staining, percentage of patients with increased goblet cell density, and meibomian gland expression were also observed with 4 weeks of SYSB over SAL. No AEs were reported for either treatment group; best-corrected visual acuity and ocular signs remained stable or improved compared with baseline. SYSB restored tear film stability, improved ocular surface healing, and improved meibomian gland functionality after 4 weeks of use in patients with lipid-deficient DE. No AEs were reported with either SYSB or SAL.

Non-linear effects in electron cyclotron current drive applied for the stabilization of neoclassical tearing modes

NARCIS (Netherlands)

Ayten, B.; Westerhof, E.; ASDEX Upgrade team,

2014-01-01

Due to the smallness of the volumes associated with the flux surfaces around the O-point of a magnetic island, the electron cyclotron power density applied inside the island for the stabilization of neoclassical tearing modes (NTMs) can exceed the threshold for non-linear effects as derived

Neoclassical tearing modes in DIII-D and calculations of the stabilizing effects of localized electron cyclotron current drive

International Nuclear Information System (INIS)

Prater, R.; La Haye, R. J.; Lin-Liu, Y. R.; Lohr, J.; Perkins, F. W.; Bernabei, S.; Wong, K.-L.; Harvey, R. W.

1999-01-01

Neoclassical tearing modes are found to limit the achievable beta in many high performance discharges in DIII-D. Electron cyclotron current drive within the magnetic islands formed as the tearing mode grows has been proposed as a means of stabilizing these modes or reducing their amplitude, thereby increasing the beta limit by a factor around 1.5. Some experimental success has been obtained previously on Asdex-U. Here we examine the parameter range in DIII-D in which this effect can best be studied

Stabilized chromium oxide film

Science.gov (United States)

Garwin, Edward L.; Nyaiesh, Ali R.

1988-01-01

Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

The relation between invasive and non-invasive tear break-up time ...

African Journals Online (AJOL)

Tear stability normal to Nigerians with consideration of gender and age has not been reported. Tear stability in young adults was measured using invasive and non-invasive tear break-up time (TBUT and NIBUT). Forty –five subjects aged 20 to 30 years were selected from among the students of University of. Benin, Edo ...

Antimicrobial compounds in tears.

Science.gov (United States)

McDermott, Alison M

2013-12-01

The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tear exchange and contact lenses: a review.

Science.gov (United States)

Muntz, Alex; Subbaraman, Lakshman N; Sorbara, Luigina; Jones, Lyndon

2015-01-01

Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Effects of wearing a daily disposable lens on tear film: a randomised controlled trial.

Science.gov (United States)

Chong, Pamela Qin Yi; Yeo, Sharon; Too, Cheah Loon; Boo, Cynthia; Tong, Louis

2016-05-01

Contact lens-induced dry eye is commonly encountered, although its extent is not well documented with daily disposable lenses. A novel type of contact lens system incorporating moisturising agent (alginic acid) has been developed. The aim of this study was to evaluate the effect of wearing daily 2-hydroxyethyl methacrylate disposable contact lenses for seven days on tear stability, conjunctival and limbal redness and dry eye symptoms. Then, we aimed to determine whether lens solutions containing alginic acid had any influence on tear parameters. This was a seven-day parallel group double-masked clinical trial of previous contact lens wearers, where participants were randomly assigned to wearing SEED 1dayPure moisture contact lenses with (n = 15) or without alginic acid (n = 15). Tear lipid layer thickness (LLT), non-invasive tear break-up time (NIBUT), conjunctival redness, corneal fluorescein staining, tear break-up time and Schirmer I readings were measured. Symptom severity and frequency were evaluated and combined using a global score from visual analogue scales. The mean age and standard deviation of the participants was 25 ± 3.8 years. There were 24 females and six males. After reintroduction of contact lens wear for one week, there was significant improvement in the global symptom score; however, this may not be clinically significant. There were small and clinically insignificant changes in limbal and conjunctival hyperaemia but no significant changes in lipid layer thickness, Schirmer I and NIBUT in overall participants. The use of alginic acid in lens solutions did not affect these parameters compared to control lenses (p > 0.05). After seven days of wearing a modern daily disposable lens, there was no significant deterioration of tear function in a group of young contact lens wearers. In this short-term study, there was no evidence of significant benefit of lens solutions containing alginic acid used with HEMA lenses. © 2016 The Authors Clinical and

Numerical studies on the stabilization of neoclassical tearing modes by radio frequency current drive

International Nuclear Information System (INIS)

Yu, Q.; Zhang, X.D.; Guenter, S.

2004-01-01

Numerical modeling on the stabilization of neoclassical tearing modes by localized radio frequency (rf) current drive has been carried out to study the effects of various wave and plasma parameters on the stabilization and the associated physics. The change of the rf current profile due to the magnetic island has been taken into account by modeling the two-dimensional transport of the fast electrons induced by the rf wave. It is found that, when the rf deposition width is much larger than the island width, the modulated rf current drive to deposit the rf current around the island's o point has a stronger stabilizing effect than a nonmodulated one. The slowing down time of the fast electrons and the initial island width when applying the rf wave are also found to be important in determining the stabilizing effect

Improved accuracy in the estimation of the tearing mode stability parameters (Δ′ and wc) using 2D ECEI data in KSTAR

International Nuclear Information System (INIS)

Choi, Minjun J; Yun, Gunsu S; Lee, Woochang; Park, Hyeon K; Park, Young-Seok; Sabbagh, Steve A; Gibson, Kieran J; Bowman, Christopher; Domier, Calvin W; Luhmann, Neville C Jr; Bak, Jun-Gyo; Lee, Sang G

2014-01-01

The accuracy in estimation of two important tearing mode stability parameters (Δ′ and w c ) is improved by employing two-dimensional (2D) ECE imaging data which help one to overcome the resolution limit of conventional one-dimensional data. The experimentally measured 2D images are directly compared with synthetic ones from a tearing mode T e model to estimate the parameters and an excellent agreement is achieved. The results imply that the observed tearing mode is classically stable but has non-negligible bootstrap current drive. (paper)

Polymer Thin Film Stabilization.

Science.gov (United States)

Costa, A. C.; Oslanec, R.; Composto, R. J.; Vlcek, P.

1998-03-01

We study the dewetting dynamics of thin polystyrene (PS) films deposited on silicon oxide surfaces using optical (OM) and atomic force (AFM) microscopes. Quantitative analysis of the hole diameter as a function of annealing time at 175^oC shows that blending poly(styrene-block-methyl-methacrylate) (PS-b-PMMA) with PS acts to dramatically slow down the dewetting rate and even stops holes growth before they impinge. AFM studies show that the hole floor is smooth for a pure PS film but contains residual polymer for the blend. At 5% vol., a PS-b-PMMA with high molar mass and low PMMA is a more effective stabilizing agent than a low molar mass/high PMMA additive. The optimum copolymer concentration is 3% vol. beyond which film stability doesn't improve. Although dewetting is slowed down relative to pure PS, PS/PS-b-PMMA bilayers dewet at a faster rate than blends having the same overall additive concentration.

Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition.

Directory of Open Access Journals (Sweden)

Claire M Elkins

Full Text Available Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS, borate buffered saline (BBS, or Sensitive Eyes Plus Saline Solution (Sensitive Eyes, either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

T-Fix endoscopic meniscal repair: technique and approach to different types of tears.

Science.gov (United States)

Barrett, G R; Richardson, K; Koenig, V

1995-04-01

Endoscopic meniscus repair using the T-Fix suture device (Acufex Microsurgical, Inc, Mansfield, MA) allows ease of suture placement for meniscus stability without the problems associated with ancillary incisions such as neurovascular compromise. It is ideal for the central posterior horn tears that are difficult using conventional techniques. Vertical tears, bucket handle tears, flap tears, and horizontal tears can be approached using a temporary "anchor stitch" to stabilize the meniscus before T-Fix repair. The basic method of repair and our approach to these different types of tears is presented.

Spectral-domain optical coherence tomography study on dynamic changes of human tears after instillation of artificial tears.

Science.gov (United States)

Napoli, Pietro Emanuele; Satta, Giovanni Maria; Coronella, Franco; Fossarello, Maurizio

2014-07-01

To analyze in vivo the dynamic changes induced by different artificial tears (ATs) in the precorneal tear film (PCTF) and lower tear meniscus (LTM) by using spectral-domain (SD) anterior segment optical coherence tomography (OCT). We prospectively examined 42 normal human eyes by using SD-OCT imaging. On the day before OCT imaging, all enrolled subjects were evaluated for abnormalities of ocular surface. All tear film images were obtained before and after instillation of three different types of ATs (mucomimetic, lipid-based, and saline) in five serial scans: immediately (within 30 seconds), at the first, fifth, 10th, and 20th minute. Subjects received a drop of 35 μL in one randomly selected eye. All examinations were conducted in the same conditions of temperature, brightness, humidity, and time of day. Changes in the morphological pattern of both LTM and PCTF were associated with the type of artificial tear instilled on the ocular surface. Similarly, the radius of curvature (rc), the height (h), and the depth (d) showed dynamic variations depending on treatment. Although by the 20th minute, both h and d returned to baseline values in all groups, a significant difference in rc (compared with baseline) was detected for mucomimetic ATs (P = 0.04) and lipid ATs (P = 0.02). Spectral-domain OCT imaging has preliminarily proved to be a noninvasive tool to evaluate, in real time, the different changes induced by ATs instillation. An important stride in understanding the clinical response to various tear substitutes can be achieved by this objective and quantitative approach. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

[Clinical characteristics of short tear film breakup time (BUT) -type dry eye].

Science.gov (United States)

Yamamoto, Yuji; Yokoi, Norihiko; Higashihara, Hisayo; Inagaki, Kayoko; Sonomura, Yukiko; Komuro, Aoi; Kinoshita, Shigeru

2012-12-01

To evaluate the clinical characteristics and management of short tear film breakup time (BUT) -type dry eye. Clinical background and post-treatment changes of symptoms in 77 patients with short BUT -type dry eye were investigated. Treatment consisted of artificial-tear eye-drop instillation and, if necessary, the addition of a low-density-level steroid, hyaluronic acid, a low-density-level cyclopentolate prepared by ourselves and punctal plugs inserted into the upper and lower lacrimal puncta. There were three times more women than men among the patients, and the peak age of occurrence was in the twenties in the men and in the sixties in the women. Our findings show that visual display terminal (VDT) work, contact lens (CL) wear, and changes in the sex hormones may initiate subjective symptoms. Some patients had simultaneous conjunctivochalasis, allergic conjunctivitis, and meibomian gland dysfunction. Nineteen patients (24.7%) were effectively treated with eye-drop instillation alone. Thirty-seven patients (48.1%) required punctal-plug insertion, which was completely effective in only 8 of them (21.6%). Mainly young men and menopausal women contract short BUT -type dry eye. Changes in sex hormones, VDT work and CL wear may be causal, and the disease cannot be controlled by eyedrop and punctal-plug treatment alone.

Stabilization of the (2,1) tearing mode and of the current disruption in the W VII-A stellarator

International Nuclear Information System (INIS)

Bartlett, D.V.; Cannici, G.; Cattanei, G.

1980-01-01

A numerical code based on a Δ'-analysis is applied to calculate the saturated amplitude of tearing modes dependent on the current density profile. The only stellarator effect included is the additional, shearless external rotational transform in the safety factor profile q(r). In this way, the stellarator field shifts the resonant q=2 surface toward the outside, where the current density gradient is smaller, and stabilizes the (2,1) mode as observed experimentally. Also the measured dependence of the (2,1) mode amplitude on electron density and plasma current can be absolutely predicted by the calculations. - In addition to stabilizing the (2,1) tearing mode, the current disruption is suppressed in Ohmically heated W VII-A discharges for approximately >0.15. The experimental findings, together with the calculated island widths, are compared with the predictions of a theoretical model proposed by several authors to explain the current disruption. (author)

Threshold condition for nonlinear tearing modes in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Zabiego, M.F. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Callen, J.D. [Wisconsin Univ., Madison, WI (United States). Dept. of Nuclear Engineering and Engineering Physics

1996-04-01

Low-mode-number tearing mode nonlinear evolution is analyzed emphasizing the need for a threshold condition, to account for observations in tokamaks. The discussion is illustrated by two models recently introduced in the literature. Introducing a threshold condition in the tearing mode stability analysis is found to reveal some bifurcation points and thus domains of intrinsic stability in the island dynamics operational space. (author). 19 refs.

Threshold condition for nonlinear tearing modes in tokamaks

International Nuclear Information System (INIS)

Zabiego, M.F.; Callen, J.D.

1996-04-01

Low-mode-number tearing mode nonlinear evolution is analyzed emphasizing the need for a threshold condition, to account for observations in tokamaks. The discussion is illustrated by two models recently introduced in the literature. Introducing a threshold condition in the tearing mode stability analysis is found to reveal some bifurcation points and thus domains of intrinsic stability in the island dynamics operational space. (author)

Increasing the Tokamak Pressure Limit: Tearing Mode Experiments in DIII-D

International Nuclear Information System (INIS)

La Haye, R.J.

2005-01-01

Since its reconfiguration in 1986, DIII-D has performed a number of experiments involving resistive magnetohydrodynamic (MHD) stability. These were and are directed to understand the conditions in which confinement and beta reducing tearing mode islands form, how to avoid them, and if unavoidable, how to stabilize them. Coils for correction of toroidal nonaxisymmetry have been developed to avoid error field locked mode islands. Basic classical tearing mode stability physics has been confirmed with a state-of-the-art ensemble of profile diagnostics, MHD equilibrium reconstruction, and stability code analysis. Neoclassical tearing mode thresholds and seeding are now much better understood with future large higher field devices expected to be 'metastable'. DIII-D is the leader in sophisticated real-time alignment of stabilizing electron cyclotron current drive on otherwise unstable rational surfaces. In all, DIII-D experiments are showing how higher stable beta with good confinement can be maintained without tearing mode islands limiting the plasma pressure

Improvement of RVNRL film properties by adding fumed silica and hydroxy apatite

Directory of Open Access Journals (Sweden)

Adul Thiangchanya

2003-01-01

Full Text Available The effect of adding fumed silica and hydroxy apatite to Radiation Vulcanized Natural Rubber Latex (RVNRL for improving tear strength, aging properties, degradability and water-soluble protein content of rubber films has been investigated. The addition of fumed silica and hydroxy apatite in RVNRL improves tear strength and aging properties of rubber films, whereas tensile strength and degradability of rubber films were unchanged during storage at room temperature. The water-soluble protein content in rubber films was reduced by immobilization of the fumed silica and hydroxy apatite and enhanced by addition of ZnO. This may reduce allergy problems of natural rubber latex products caused by water-soluble protein. The MST of the RVNRL with fumed silica and hydroxy apatite indicated that the latex must be used within two months after mixing because of its stability.

Ocular Surface and Tear Film Changes in Older Women Working with Computers

Directory of Open Access Journals (Sweden)

Alfredo Ribelles

2015-01-01

Full Text Available The aim of this work is to investigate changes in the ocular surface (OS and tear film (TF by means of questionnaire-based subjective symptoms, TF break-up time, Schirmer test, and TF analysis in women working with computers and to analyze the effects of the oral supplementation with antioxidants/omega 3 fatty acids (A/ω3 in the OS outcomes. Women aged 40–65 years (n=148 were recruited at the Administrative Offices of Valencia (Spain and distributed into two age groups, 40–52 years (AGE1; n=87 and 53–65 years (AGE2; n=61, and then subdivided according to being (or not computer users (CUG; NCUG during the workday. Homogeneous subgroups were randomly assigned (or not to the daily intake of three pills of A/ω3 for three months. At baseline and at the end of follow-up, personalized interviews and ocular examination were done. Reflex tear samples were collected from the inferior meniscus and processed for a multiplexed particle-based flow cytometry assay to measure proinflammatory molecules. Statistics were performed using the SPSS 15.0 program. The OS pathology was clinically evident in the AGE1-CUG (33% versus the AGE2-CUG (64% of women. Significantly higher interleukins-1β and -6 tear levels were found in the AGE1 versus the AGE2 women employees (P=0.006 and P=0.001, resp., as well as in the CUG versus the NCUG (P=0.001 and P=0.000, resp.. Supplementation with A/ω3 positively influenced the OS pathology as manifested by the amelioration of the clinical signs/symptoms related to computer uses. Strategies involving a safe environment and oral micronutrient supplements may be managed within eye-care standards in older women.

Threshold condition for nonlinear tearing modes in tokamaks

International Nuclear Information System (INIS)

Zabiego, M.F.; Callen, J.D.

1996-03-01

Low-mode-number tearing, mode nonlinear evolution is analyzed emphasizing the need for a threshold condition, to account for observations in tokamaks. The discussion is illustrated by two models recently introduced in the literature. The models can be compared with the available data and/or serve as a basis for planning some experiments in order to either test theory (by means of beta-limit scaling laws, as proposed in this paper) or attempt to control undesirable tearing modes. Introducing a threshold condition in the tearing mode stability analysis is found to reveal some bifurcation points and thus domains of intrinsic stability in the island dynamics operational space

Time-dependent simulations of feedback stabilization of neoclassical tearing modes in KSTAR plasmas

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyungjin [Department of Nuclear Engineering, Seoul National University, Seoul (Korea, Republic of); Na, Yong-Su, E-mail: ysna@snu.ac.kr [Department of Nuclear Engineering, Seoul National University, Seoul (Korea, Republic of); Kim, Hyun-Seok [Department of Nuclear Engineering, Seoul National University, Seoul (Korea, Republic of); Maraschek, M. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching bei München (Germany); Park, Y.S. [Department of Applied Physics and Applied Mathematics, Columbia University, New York (United States); Stober, J. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching bei München (Germany); Terzolo, L. [National Fusion Research Institute, Daejeon (Korea, Republic of); Zohm, H. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching bei München (Germany)

2014-06-15

A simulation is performed for feedback stabilization of neoclassical tearing mode (NTM) by electron cyclotron current drive (ECCD) for KSTAR in preparation for experiments. An integrated numerical system is constructed by coupling plasma transport, NTM stability, and heating and current drive modules and applied to a KSTAR plasma by assuming similar experimental conditions as ASDEX Upgrade to predict NTM behaviors in KSTAR. System identification is made with database produced by predictive simulations with this integrated numerical system so that three plasma response models are extracted which describe the relation between the EC poloidal launcher angle and the island width in KSTAR. Among them, the P1DI model exhibiting the highest fit accuracy is selected for designing a feedback controller based on the classical Proportional–Integral–Derivative (PID) concept. The controller is coupled with the integrated numerical system and applied to a simulation of NTM stabilization. It is observed that the controller can search and fully stabilize the mode even though the poloidal launch angle is misaligned with the island initially.

Artificial tears potpourri: a literature review

Directory of Open Access Journals (Sweden)

Moshirfar M

2014-07-01

Full Text Available Majid Moshirfar,1 Kasey Pierson,2,* Kamalani Hanamaikai,3,* Luis Santiago-Caban,1 Valliammai Muthappan,1 Samuel F Passi11Department of Ophthalmology, John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA; 2University of Arizona College of Medicine, Phoenix, Phoenix, AZ, USA; 3A T Still University, School of Osteopathic Medicine in Arizona, Mesa, AZ, USA *These authors contributed equally to this work Abstract: Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived. Keywords: dry eye, tear film, dysfunctional tear syndrome, ophthalmic lubricant, artificial tears, lipid layer, tear osmolarity, TBUT, Systane®, Refresh®, Blink®, GenTeal®, Soothe®, Lacrisert®, ocular surface inflammatory disease, Sjogren�

Meniscotibial (coronary) ligament tears

International Nuclear Information System (INIS)

El-Khoury, G.Y.; Usta, H.Y.; Berger, R.A.

1984-01-01

Preservation of the meniscus whenever possible is essential in maintaining knee stability and preventing premature osteoarthritis. Peripheral meniscal tears are the most amenable to surgical repair. This study evaluates the peripheral attachments of the medial meniscus and focuses on a specific tear limited to the meniscotibial ligament (coronary ligament). The diagnosis is made arthrographically when the medial meniscus floats above the tibial plateau without separating completely from the capsule. The lateral meniscus is rarely involved in this type of injury. (orig.)

A fresh look at electron cyclotron current drive power requirements for stabilization of tearing modes in ITER

Energy Technology Data Exchange (ETDEWEB)

La Haye, R. J., E-mail: lahaye@fusion.gat.com [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2015-12-10

ITER is an international project to design and build an experimental fusion reactor based on the “tokamak” concept. ITER relies upon localized electron cyclotron current drive (ECCD) at the rational safety factor q=2 to suppress or stabilize the expected poloidal mode m=2, toroidal mode n=1 neoclassical tearing mode (NTM) islands. Such islands if unmitigated degrade energy confinement, lock to the resistive wall (stop rotating), cause loss of “H-mode” and induce disruption. The International Tokamak Physics Activity (ITPA) on MHD, Disruptions and Magnetic Control joint experiment group MDC-8 on Current Drive Prevention/Stabilization of Neoclassical Tearing Modes started in 2005, after which assessments were made for the requirements for ECCD needed in ITER, particularly that of rf power and alignment on q=2 [1]. Narrow well-aligned rf current parallel to and of order of one percent of the total plasma current is needed to replace the “missing” current in the island O-points and heal or preempt (avoid destabilization by applying ECCD on q=2 in absence of the mode) the island [2-4]. This paper updates the advances in ECCD stabilization on NTMs learned in DIII-D experiments and modeling during the last 5 to 10 years as applies to stabilization by localized ECCD of tearing modes in ITER. This includes the ECCD (inside the q=1 radius) stabilization of the NTM “seeding” instability known as sawteeth (m/n=1/1) [5]. Recent measurements in DIII-D show that the ITER-similar current profile is classically unstable, curvature stabilization must not be neglected, and the small island width stabilization effect from helical ion polarization currents is stronger than was previously thought [6]. The consequences of updated assumptions in ITER modeling of the minimum well-aligned ECCD power needed are all-in-all favorable (and well-within the ITER 24 gyrotron capability) when all effects are included. However, a “wild card” may be broadening of the localized

The Effect of Tear Supplementation with 0.15% Preservative-Free Zinc-Hyaluronate on Ocular Surface Sensations in Patients with Dry Eye.

Science.gov (United States)

Perényi, Kristóf; Dienes, Lóránt; Kornafeld, Anna; Kovács, Balázs; Kiss, Huba J; Szepessy, Zsuzsanna; Nagy, Zoltán Z; Barsi, Árpád; Acosta, M Carmen; Gallar, Juana; Kovács, Illés

To evaluate the effect of tear supplementation with preservative free 0.15% zinc-hyaluronate on ocular surface sensations and corneal sensitivity in dry eye patients. Ocular surface sensations were assessed using the ocular surface disease index (OSDI) questionnaire and by recording ocular sensations during forced blinking in parallel with noninvasive tear film breakup time measurement in 20 eyes of 20 dry eye patients. Corneal sensitivity thresholds to selective stimulation of corneal mechano-, thermal- and chemical receptors were measured using the Belmonte gas esthesiometer. All baseline measurements were repeated after 1 month of treatment with 0.15% zinc-hyaluronate. After 1 month, a significant decrease in mean OSDI score (from 35.66 ± 12.36 to 15.03 ± 11.22; P  0.05). Prolonged use of 0.15% zinc-hyaluronate results in an improvement of tear film stability and a decrease of dry eye complaints. The decrease in corneal mechano-and polymodal receptor excitability suggests that zinc-hyaluronate helps to recover normal corneal sensitivity, and thus might have a beneficial additional effect on reducing ocular surface complaints in dry eye patients.

MR imaging of the traumatic triangular fibrocartilaginous complex tear

Science.gov (United States)

Griffith, James F.; Fung, Cindy S. Y.; Lee, Ryan K. L.; Tong, Cina S. L.; Wong, Clara W. Y.; Tse, Wing Lim; Ho, Pak Cheong

2017-01-01

Triangular fibrocartilage complex is a major stabilizer of the distal radioulnar joint (DRUJ). However, triangular fibrocartilage complex (TFCC) tear is difficult to be diagnosed on MRI for its intrinsic small and thin structure with complex anatomy. The purpose of this article is to review the anatomy of TFCC, state of art MRI imaging technique, normal appearance and features of tear on MRI according to the Palmar’s classification. Atypical tear and limitations of MRI in diagnosis of TFCC tear are also discussed. PMID:28932701

Surface tearing modes in tokamaks

International Nuclear Information System (INIS)

Takizuka, Tomonori; Kurita, Gen-ichi; Azumi, Masafumi; Takeda, Tatsuoki

1985-10-01

Surface tearing modes in tokamaks are studied numerically and analytically. The eigenvalue problem is solved to obtain the growth rate and the mode structure. We investigate in detail dependences of the growth rate of the m/n = 2/1 resistive MHD modes on the safety factor at the plasma surface, current profile, wall position, and resistivity. The surface tearing mode moves the plasma surface even when the wall is close to the surface. The stability diagram for these modes is presented. (author)

Two- and three-dimensional characterizations of hot tears in a Al-Mg-Si alloy laser weld

Energy Technology Data Exchange (ETDEWEB)

Fabregue, D. [Universite de Lyon, INSA-Lyon, MATEIS, CNRS UMR5510, 7 Avenue Jean Capelle, F-69621 Villeurbanne (France)], E-mail: damien.fabregue@insa-lyon.fr; Deschamps, A.; Suery, M. [SIMAP, Grenoble-INP, CNRS-UJF, BP 75, 38402 St Martin d' Heres Cedex (France); Proudhon, H. [Universite de Lyon, INSA-Lyon, MATEIS, CNRS UMR5510, 7 Avenue Jean Capelle, F-69621 Villeurbanne (France)

2008-08-15

Hot tears in 6xxx aluminium alloy laser welds are characterized. They are shown to be intergranular, originating from fracture of liquid films without plasticity of the surrounding grains. The hot tear initiates on both sides of the fusion zone, follows the liquid films between the columnar grains of the weld line and then propagates around the equiaxed grains of the fusion zone centre. By using three-dimensional X-ray tomography, the exact shape of the hot tears has been visualized.

Two- and three-dimensional characterizations of hot tears in a Al-Mg-Si alloy laser weld

International Nuclear Information System (INIS)

Fabregue, D.; Deschamps, A.; Suery, M.; Proudhon, H.

2008-01-01

Hot tears in 6xxx aluminium alloy laser welds are characterized. They are shown to be intergranular, originating from fracture of liquid films without plasticity of the surrounding grains. The hot tear initiates on both sides of the fusion zone, follows the liquid films between the columnar grains of the weld line and then propagates around the equiaxed grains of the fusion zone centre. By using three-dimensional X-ray tomography, the exact shape of the hot tears has been visualized

[A study on the diagnostic value of tear film objective scatter index in dry eye].

Science.gov (United States)

Su, Y D; Liang, Q F; Wang, N L; Antoine, Labbè

2017-09-11

Objective: To study the sensitivity and specificity of tear film objective scatter index to the diagnosis dry eye disease (DED). Methods: A prospective case-controlled study. Fifty-three patients with DED and 32 healthy age- and sex-matched control subjects were included from July to October 2016. All subjects underwent the examinations sequentially as follows: evaluation of ocular surface disease symptoms using the Ocular Surface Disease Index, optical quality detection, lipid layer thickness, tear film breakup time and SchirmerⅠtest. With Optical Quality Analysis SystemⅡ, the values of modulation transfer function cut off, basic objective scatter index (OSI) and total OSI were measured. To eliminate the influence of other refractive media, the tear film OSI (TF-OSI) was calculated, and the difference in TF-OSI between two groups was analyzed with the independent-samples t test. Spearman's correlation analysis was used to detect the correlation of each parameter in the DED group. With the receiver operating characteristic curve and the area under the curve (AUC), the specificity and sensitivity of TF-OSI and other parameters were described to differentiate DED from normal eyes. Results: In the dry eye group, the value of modulation transfer function cut off (32.07±11.95) was significantly lower than the normal group (39.38±9.44, t=- 3.096, P= 0.003) , and the mean value and dispersion of TF-OSI (0.50±0.43, 0.52±0.81) were higher than the normal group (0.21±0.16, 0.12±0.01) ( t= 4.300, P= 0.000, t= 3.546, P= 0.001) . The mean value of TF-OSI had a positive correlation with lipid layer thickness ( r= 0.365, P= 0.007) and dispersion of TF-OSI ( r= 0.581, P= 0.000), and a negative correlation with MTF cut off ( r=- 0.368, P= 0.007). To the diagnostic value of DED, the mean value of TF-OSI had a sensitivity of 0.736, a specificity of 0.762, and the AUC was 0.764. The dispersion of TF-OSI had a sensitivity of 0.811 and a specificity of 0.810, and the AUC was 0

Tearing relaxation and the globalization of transport in field-reversed configurations

International Nuclear Information System (INIS)

Steinhauer, Loren; Barnes, D. C.

2009-01-01

Tearing instability of field-reversed configurations (FRC) is investigated using the method of neighboring equilibria. It is shown that the conducting wall position in experiment lies very close to the location needed for tearing stability. This strongly suggests that vigorous but benign tearing modes, acting globally, are the engine of continual self-organization in FRCs, i.e., tearing relaxation. It also explains the ''profile consistency'' and anomalous loss rate of magnetic flux. In effect, tearing globalizes the effect of edge-driven transport.

Stability of coupled tearing and twisting modes in tokamaks

International Nuclear Information System (INIS)

Fitzpatrick, R.

1994-03-01

A dispersion relation is derived for resistive modes of arbitrary parity in a tokamak plasma. At low mode amplitude, tearing and twisting modes which have nonideal MHD behavior at only one rational surface at a time in the plasma are decoupled via sheared rotation and diamagnetic flows. At higher amplitude, more unstable open-quote compound close-quote modes develop which have nonideal behavior simultaneously at many surfaces. Such modes possess tearing parity layers at some of the nonideal surfaces, and twisting parity layers at others, but mixed parity layers are generally disallowed. At low mode number, open-quote compound close-quote modes are likely to have tearing parity layers at all of the nonideal surfaces in a very low-β plasma, but twisting parity layers become more probable as the plasma β is increased. At high mode number, unstable twisting modes which exceed a critical amplitude drive conventional magnetic island chains on alternate rational surfaces, to form an interlocking structure in which the O-points and X-points of neighboring chains line up

Modeling of Neoclassical Tearing Mode Stability for Generalized Toroidal Geometry

International Nuclear Information System (INIS)

A.L. Rosenberg; D.A. Gates; A. Pletzer; J.E. Menard; S.E. Kruger; C.C. Hegna; F. Paoletti; S. Sabbagh

2002-01-01

Neoclassical tearing modes (NTMs) can lead to disruption and loss of confinement. Previous analysis of these modes used large aspect ratio, low beta (plasma pressure/magnetic pressure) approximations to determine the effect of NTMs on tokamak plasmas. A more accurate tool is needed to predict the onset of these instabilities. As a follow-up to recent theoretical work, a code has been written which computes the tearing mode island growth rate for arbitrary tokamak geometry. It calls PEST-3 [A. Pletzer et al., J. Comput. Phys. 115, 530 (1994)] to compute delta prime, the resistive magnetohydrodynamic (MHD) matching parameter. The code also calls the FLUXGRID routines in NIMROD [A.H. Glasser et al., Plasma Phys. Controlled Fusion 41, A747 (1999)] for Dnc, DI and DR [C.C. Hegna, Phys. Plasmas 6, 3980 (1999); A.H. Glasser et al., Phys. Fluids 18, 875 (1975)], which are the bootstrap current driven term and the ideal and resistive interchange mode criterion, respectively. In addition to these components, the NIMROD routines calculate alphas-H, a new correction to the Pfirsch-Schlter term. Finite parallel transport effects were added and a National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)] equilibrium was analyzed. Another program takes the output of PEST-3 and allows the user to specify the rational surface, island width, and amount of detail near the perturbed surface to visualize the total helical flux. The results of this work will determine the stability of NTMs in an spherical torus (ST) [Y.-K.M. Peng et al., Nucl. Fusion 26, 769 (1986)] plasma with greater accuracy than previously achieved

The impact of lipid composition on the stability of the tear fluid lipid layer

DEFF Research Database (Denmark)

Kulovesi, P.; Telenius, J.; Koivuniemi, A.

2012-01-01

The tear fluid protects the corneal epithelium from drying and pathogens and it also provides nutrients to these cells. Tear fluid is composed of an aqueous layer as well as a lipid layer that resides at the air-tear interface. The function of the lipid layer is to lower the surface tension of th......-neutral lipid ratio. The results provide a plausible rationale for the development of dry eye syndrome in blepharitis patients.......The tear fluid protects the corneal epithelium from drying and pathogens and it also provides nutrients to these cells. Tear fluid is composed of an aqueous layer as well as a lipid layer that resides at the air-tear interface. The function of the lipid layer is to lower the surface tension...

Tearing modes with pressure gradient effect in pair plasmas

International Nuclear Information System (INIS)

Cai Huishan; Li Ding; Zheng Jian

2009-01-01

The general dispersion relation of tearing mode with pressure gradient effect in pair plasmas is derived analytically. If the pressure gradients of positron and electron are not identical in pair plasmas, the pressure gradient has significant influence at tearing mode in both collisionless and collisional regimes. In collisionless regime, the effects of pressure gradient depend on its magnitude. For small pressure gradient, the growth rate of tearing mode is enhanced by pressure gradient. For large pressure gradient, the growth rate is reduced by pressure gradient. The tearing mode can even be stabilized if pressure gradient is large enough. In collisional regime, the growth rate of tearing mode is reduced by the pressure gradient. While the positron and electron have equal pressure gradient, tearing mode is not affected by pressure gradient in pair plasmas.

Shifting the IGF-axis: An age-related decline in human tear IGF-1 correlates with clinical signs of dry eye.

Science.gov (United States)

Patel, Roshni; Zhu, Meifang; Robertson, Danielle M

2018-02-06

The human corneal epithelium expresses both the insulin-like growth factor type 1 receptor (IGF-1R) and the IGF-1R/insulin receptor (INSR) hybrid. Despite the previous identification of IGF-1 in human tear fluid, little is known regarding the regulation of IGF-1 in tear fluid and its role in corneal epithelial homeostasis. In the present study, we investigated the impact of biological parameters on the concentration of human tear levels of IGF-1. Tear levels of IGF-1 were measured in 41 healthy, human volunteers without any reported symptoms of dry eye. All volunteers underwent standard biomicroscopic examination of the cornea and tear film. In a subgroup of volunteers, corneal staining with sodium fluorescein, tear film break up time and tear production using a Schirmer's test strip were measured to assess clinical signs of dry eye. Tears were collected from the inferior tear meniscus using glass microcapillary tubes and IGF-1 levels were measured using a solid phase sandwich ELISA. Tear levels of IGF-1 were highest in young adults and significantly decreased in older adults (P = 0.003). There were no differences in tear IGF-1 between males and females (P = 0.628). Tear IGF-1 levels were correlated with tear film break up time (R = 0.738) and tear production (R = 0.826). These data indicate that there is a progressive decline in tear IGF-1 due to aging that is associated with clinical signs of dry eye. This effect is likely due to age-related changes in the lacrimal gland. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stability of Polymer Ultrathin Films (Top-Down Approach.

Science.gov (United States)

Bal, Jayanta Kumar; Beuvier, Thomas; Unni, Aparna Beena; Chavez Panduro, Elvia Anabela; Vignaud, Guillaume; Delorme, Nicolas; Chebil, Mohamed Souheib; Grohens, Yves; Gibaud, Alain

2015-08-25

In polymer physics, the dewetting of spin-coated polystyrene ultrathin films on silicon remains mysterious. By adopting a simple top-down method based on good solvent rinsing, we are able to prepare flat polystyrene films with a controlled thickness ranging from 1.3 to 7.0 nm. Their stability was scrutinized after a classical annealing procedure above the glass transition temperature. Films were found to be stable on oxide-free silicon irrespective of film thickness, while they were unstable (2.9 nm) on 2 nm oxide-covered silicon substrates. The Lifshitz-van der Waals intermolecular theory that predicts the domains of stability as a function of the film thickness and of the substrate nature is now fully reconciled with our experimental observations. We surmise that this reconciliation is due to the good solvent rinsing procedure that removes the residual stress and/or the density variation of the polystyrene films inhibiting thermodynamically the dewetting on oxide-free silicon.

Comparison between numerical and analytical results on the required rf current for stabilizing neoclassical tearing modes

Science.gov (United States)

Wang, Xiaojing; Yu, Qingquan; Zhang, Xiaodong; Zhang, Yang; Zhu, Sizheng; Wang, Xiaoguang; Wu, Bin

2018-04-01

Numerical studies on the stabilization of neoclassical tearing modes (NTMs) by electron cyclotron current drive (ECCD) have been carried out based on reduced MHD equations, focusing on the amount of the required driven current for mode stabilization and the comparison with analytical results. The dependence of the minimum driven current required for NTM stabilization on some parameters, including the bootstrap current density, radial width of the driven current, radial deviation of the driven current from the resonant surface, and the island width when applying ECCD, are studied. By fitting the numerical results, simple expressions for these dependences are obtained. Analysis based on the modified Rutherford equation (MRE) has also been carried out, and the corresponding results have the same trend as numerical ones, while a quantitative difference between them exists. This difference becomes smaller when the applied radio frequency (rf) current is smaller.

Nonlinear drift tearing mode

International Nuclear Information System (INIS)

Zelenyj, L.M.; Kuznetsova, M.M.

1989-01-01

Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

Ponderomotive modification of drift tearing modes

International Nuclear Information System (INIS)

Urquijo, G.; Singh, R.; Sen, A.

1997-01-01

The linear characteristics of drift tearing modes are investigated in the presence of a significant background of radio-frequency (RF) waves in the ion cyclotron range of frequencies. The ponderomotive force, arising from the radial gradients in the RF field energy, is found to significantly modify the inner layer solutions of the drift tearing modes. It can have a stabilizing influence, even at moderate RF powers, provided the field energy has a decreasing radial profile at the mode rational surface. (author)

Low-temperature technique for thick film resist stabilization and curing

Science.gov (United States)

Minter, Jason P.; Wong, Selmer S.; Marlowe, Trey; Ross, Matthew F.; Narcy, Mark E.; Livesay, William R.

1999-06-01

For a range of thick film photoresist applications, including MeV ion implant processing, thin film head manufacturing, and microelectromechanical systems processing, there is a need for a low-temperature method for resist stabilization and curing. Traditional methods of stabilizing or curing resist films have relied on thermal cycling, which may not be desirable due to device temperature limitations or thermally-induced distortion of the resist features.

Investigation of temperature stability of ITO films characteristics

Directory of Open Access Journals (Sweden)

Troyan Pavel

2018-01-01

Full Text Available The paper represents research of thermal stability of optical and electro-physical parameters of ITO films deposited using various techniques. Variation of optical and electro-physical parameters was recorded using spectroscopy, and Hall’s and four-probe measurements. The best thermal stability was demonstrated by ITO films deposited by metal target sputtering In(90%/Sn(10% in mixture of gases O2 (25% + Ar (75% with further annealing in air atmosphere. This enables to apply this technique for production of thin film transparent resistive elements capable to heat the translucent structures up to 100°C without deterioration of their parameters.

Antioxidant content and ultraviolet absorption characteristics of human tears.

Science.gov (United States)

Choy, Camus Kar Man; Cho, Pauline; Benzie, Iris F F

2011-04-01

Dry eye syndrome is a common age-related disorder, and decreased antioxidant/ultraviolet (UV) radiation protection in tears may be part of the cause. This study aimed to compare the tear antioxidant content and flow rate in young and older adults. The total antioxidant content and UV absorbing properties of various commercially available ophthalmic solutions used to alleviate dry eye symptoms were also examined. Minimally stimulated tears were collected from 120 healthy Chinese adults with no ocular pathology. Two age groups were studied: 19 to 29 years (n = 58) and 50 to 75 years (n = 62). Tear samples from each subject and 13 ophthalmic solutions were analyzed for total antioxidant content (as the Ferric Reducing/Antioxidant Power value). Tear flow rates were estimated from time taken to collect a fixed volume of tear fluid. UV absorbance spectra of pooled fresh reflex tear fluid and the ophthalmic solutions were determined. Results showed that the antioxidant content of minimally stimulated tears from older subjects (398 ± 160 μmol/l) was not significantly lower than that of younger subjects (348 ± 159 μmol/l; p = 0.0915). However, there was a significant difference in the tear flow rates between the two groups (p tears. The effect of low flow rate on the dynamic antioxidant supply to the corneal surface indicates that older subjects have poorer overall defense against photooxidative and other oxidative processes. This could predispose older persons to corneal stress and development of dry eye syndrome. The commercially available artificial tears tested lack both the antioxidant content and UV absorbing characteristics of natural tears. Artificial tears formulations that help restore natural antioxidant and UV absorbing properties to the tear film of the aging eye may help prevent or improve dry eye symptoms and promote ocular health.

Instability threshold of neoclassical tearing mode, double tearing mode and off-axis sawteeth crash in tokamaks

International Nuclear Information System (INIS)

Li, D.

2001-01-01

The neoclassical and double tearing modes have been analyzed with related new phenomena in the reversed magnetic shear tokamak plasmas. The instability threshold, and the linear and nonlinear evolution are derived for the neoclassical tearing modes. It is found that the perturbed bootstrap current in the resistive layer has a stabilizing effect while the equilibrium bootstrap current in the outer region can destabilize the modes. The dispersion relation is derived for the double tearing mode. It is found that the onset of ''annular crash'' is due to the fast reconnection of the hot and cold islands, triggered by the interaction of both branches. The onset of ''core crash'' is mainly due to the coalescence between the hot islands, triggered by the explosive growth of the inner branch. (author)

Instability threshold of neoclassical tearing mode, double tearing mode and off-axis sawteeth crash in tokamaks

International Nuclear Information System (INIS)

Li Ding

1999-01-01

The neoclassical and double tearing modes have been analyzed with related new phenomena in the reversed magnetic shear tokamak plasmas. The instability threshold, and the linear and nonlinear evolution are derived for the neoclassical tearing modes. It is found that the perturbed bootstrap current in the resistive layer has a stabilizing effect while the equilibrium bootstrap current in the outer region can destabilize the modes. The dispersion relation is derived for the double tearing mode. It is found that the onset of 'annular crash' is due to the fast reconnection of the hot and cold islands, triggered by the interaction of both branches. The onset of 'core crash' is mainly due to the coalescence between the hot islands, triggered by the explosive growth of the inner branch. (author)

The effect of Meibomian lipids and tear proteins on evaporation rate under controlled in vitro conditions.

Science.gov (United States)

Herok, George Henryk; Mudgil, Poonam; Millar, Thomas James

2009-07-01

The lipid layer of the tear film is associated with preventing evaporative loss. The ability of human Meibomian lipids to reduce evaporation in vitro was tested. Films of human or animal Meibomian lipids or mixtures of cholesterol and phosphatidylcholine were spread on the surface of either artificial buffer or on whole tears and placed on a mass balance that was enclosed in a sealed chamber. The temperature was adjusted to 37 degrees C and gas flow was controlled. Increasing the amounts of Meibomian lipids gave a very small reduction in evaporation. It was concluded from these in vitro experiments that prevention of evaporation from the tear film is not due to the Meibomian lipids alone, but is more likely to be due to a complex interaction between components of the aqueous and the Meibomian lipids.

Tear Osmolarity and Correlation With Ocular Surface Parameters in Patients With Dry Eye.

Science.gov (United States)

Mathews, Priya M; Karakus, Sezen; Agrawal, Devika; Hindman, Holly B; Ramulu, Pradeep Y; Akpek, Esen K

2017-11-01

To analyze the distribution of tear film osmolarity in patients with dry eye and its association with other ocular surface parameters. Tear osmolarity and other quantitative dry eye parameters were obtained from patients with 1) clinically significant dry eye (significant symptoms and ocular surface staining, n = 131), 2) symptoms-only dry eye (significant symptoms but no significant ocular surface staining, n = 52), and 3) controls (no significant symptoms or staining, n = 42). Tear osmolarity varied significantly across groups (P = 0.01), with patients with clinically significant dry eye having the highest tear osmolarity (312.0 ± 16.9 mOsm/L), control patients having the lowest tear osmolarity (305.6 ± 9.7 mOsm/L), and patients with symptoms-only dry eye falling in between (307.4 ± 5.6 mOsm/L). Patients with clinically significant dry eye also tended to have a greater intereye difference in osmolarity (12.0 ± 13.4) than did the individuals with symptoms-only dry eye (9.1 ± 12.4) and controls (9.0 ± 7.4) (P = 0.06). In multivariable regression models, higher tear osmolarity was associated with higher Ocular Surface Disease Index, discomfort subscore (P = 0.02), and higher corneal and conjunctival staining scores (P eye tear osmolarity was not correlated with the corresponding tear film breakup time or Schirmer test (P > 0.05 for both). Individuals with symptomatic dry eye that is not yet clinically significant seem to have higher and more variable osmolarity measurements than controls, potentially indicating that changes in osmolarity precede clinical findings.

The Effect of Tear Supplementation on Ocular Surface Sensations during the Interblink Interval in Patients with Dry Eye.

Directory of Open Access Journals (Sweden)

Lóránt Dienes

Full Text Available To investigate the characteristics of ocular surface sensations and corneal sensitivity during the interblink interval before and after tear supplementation in dry eye patients.Twenty subjects (41.88±14.37 years with dry eye symptoms were included in the dry eye group. Fourteen subjects (39.13±11.27 years without any clinical signs and/or symptoms of dry eye were included in the control group. Tear film dynamics was assessed by non-invasive tear film breakup time (NI-BUT in parallel with continuous recordings of ocular sensations during forced blinking. Corneal sensitivity to selective stimulation of corneal mechano-, cold and chemical receptors was assessed using a gas esthesiometer. All the measurements were made before and 5 min after saline and hydroxypropyl-guar (HP-guar drops.In dry eye patients the intensity of irritation increased rapidly after the last blink during forced blinking, while in controls there was no alteration in the intensity during the first 10 sec followed by an exponential increase. Irritation scores were significantly higher in dry eye patients throughout the entire interblink interval compared to controls (p0.05.Ocular surface irritation responses due to tear film drying are considerably increased in dry eye patients compared to normal subjects. Although tear supplementation improves the protective tear film layer, and thus reduce unpleasant sensory responses, the rapid rise in discomfort is still maintained and might be responsible for the remaining complaints of dry eye patients despite the treatment.

Stability of sputter deposited ZnO:Cr films against acids

International Nuclear Information System (INIS)

Shinoda, Makoto; Nishide, Toshikazu; Sawada, Yutaka; Hosaka, Masato; Matsumoto, Toshihiko.

1993-01-01

ZnO:Cr films were deposited on water-cooled soda-lime glass substrates at room temperature in an Ar atmosphere by rf magnetron sputtering of a ZnO target on which Cr chips were placed. The films exhibited extraordinary stability against acids such as HCl or HNO 3 , and also high resistivities similar to those of ZnO films. The addition of Cr suppressed the growth of ZnO grains which resulted in the formation of a dense film with a smooth surface. The stability and high resistivity displayed by the ZnO:Cr films can be attributed to the formation of a chromium-oxide-rich grain boundary. (author)

Stabilization of thin liquid films by repulsive van der waals force

KAUST Repository

Li, Erqiang

2014-05-13

Using high-speed video recording of bubble rise experiments, we study the stability of thin liquid films trapped between a rising bubble and a surfactant-free liquid-liquid meniscus interface. Using different combinations of nonpolar oils and water that are all immiscible, we investigate the extent to which film stability can be predicted by attractive and repulsive van der Waals (vdW) interactions that are indicated by the relative magnitude of the refractive indices of the liquid combinations, for example, water (refractive index, n = 1.33), perfluorohexane (n = 1.23), and tetradecane (n = 1.43). We show that, when the film-forming phase was oil (perfluorohexane or tetradecane), the stability of the film could always be predicted from the sign of the vdW interaction, with a repulsive vdW force resulting in a stable film and an attractive vdW force resulting in film rupture. However, if aqueous electrolyte is the film-forming bulk phase between the rising air bubble and the upper oil phase, the film always ruptured, even when a repulsive vdW interaction was predicted. We interpret these results as supporting the hypothesis that a short-ranged hydrophobic attraction determines the stability of the thin water film formed between an air phase and a nonpolar oil phase. © 2014 American Chemical Society.

The tear turnover and tear clearance tests - a review.

Science.gov (United States)

Garaszczuk, Izabela K; Montes Mico, Robert; Iskander, D Robert; Expósito, Alejandro Cerviño

2018-03-01

The aim is to provide a summary of methods available for the assessment of tear turnover and tear clearance rates. The review defines tear clearance and tear turnover and describes their implication for ocular surface health. Additionally, it describes main types of techniques for measuring tear turnover, including fluorescein tear clearance tests, techniques utilizing electromagnetic spectrum and tracer molecule and novel experimental techniques utilizing optical coherence tomography and fluorescein profilometry. Areas covered: Internet databases (PubMed, Science Direct, Google Scholar) and most frequently cited references were used as a principal resource of information on tear turnover rate and tear clearance rate, presenting methodologies and equipment, as well as their definition and implications for the anterior eye surface health and function. Keywords used for data-search were as follows: tear turnover, tear clearance, fluorescein clearance, scintigraphy, fluorophotometry, tear flow, drainage, tear meniscus dynamics, Krehbiel flow and lacrimal functional unit. Expert commentary: After decades, the topic of tear turnover assessment has been reintroduced. Recently, new techniques have been developed to propose less invasive, less time consuming and simpler methodologies for the assessment of tear dynamics that have the potential to be utilized in clinical practice.

Chemically stabilized epitaxial wurtzite-BN thin film

Science.gov (United States)

Vishal, Badri; Singh, Rajendra; Chaturvedi, Abhishek; Sharma, Ankit; Sreedhara, M. B.; Sahu, Rajib; Bhat, Usha; Ramamurty, Upadrasta; Datta, Ranjan

2018-03-01

We report on the chemically stabilized epitaxial w-BN thin film grown on c-plane sapphire by pulsed laser deposition under slow kinetic condition. Traces of no other allotropes such as cubic (c) or hexagonal (h) BN phases are present. Sapphire substrate plays a significant role in stabilizing the metastable w-BN from h-BN target under unusual PLD growth condition involving low temperature and pressure and is explained based on density functional theory calculation. The hardness and the elastic modulus of the w-BN film are 37 & 339 GPa, respectively measured by indentation along direction. The results are extremely promising in advancing the microelectronic and mechanical tooling industry.

Thermal properties and stabilities of polymer thin films

International Nuclear Information System (INIS)

Kanaya, Toshiji; Kawashima, Kazuko; Inoue, Rintaro; Miyazaki, Tsukasa

2009-01-01

Recent extensive studies have revealed that polymer thin films showed very interesting but unusual thermal properties and stabilities. In the article we show that X-ray reflectivity and neutron reflectivity are very powerful tools to study the anomalous properties of polymer thin films. (author)

Phospholipids and their degrading enzyme in the tears of soft contact lens wearers.

Science.gov (United States)

Yamada, Masakazu; Mochizuki, Hiroshi; Kawashima, Motoko; Hata, Seiichiro

2006-12-01

Low tear phospholipids levels are associated with tear film instability in soft contact lens wearers. We assayed levels of phospholipids and their degrading enzyme secretory phospholipase A2 (sPLA2) both in tears and deposited on contact lenses composed of 2 hydrophilic materials after 1 day of routine use. Polymacon (Medalist; FDA group 1, low water/nonionic) and Etafilcon A (One Day Acuvue; group 4, high water/ionic) contact lenses were worn for 12 hours by 16 experienced contact lens wearers. Phospholipids in tear fluids and deposited on contact lenses were estimated by phosphorus determination with ammonium molybdate through enzymatic digestion. Double-antibody sandwich ELISA was used to determine group IIa sPLA2 concentrations, and sPLA2 activity was assayed using 1,2-diheptanoyl thio-phosphatidylcholine as substrate. Phospholipids concentrations in tears with Polymacon and Etafilcon A were 186 +/- 39 and 162 +/- 33 microg/mL, respectively. The latter concentration was significantly lower than that observed in the same subjects when not wearing contact lenses (P = 0.0023). In tears, both group IIa sPLA2 concentrations and enzymatic activity remained unchanged, regardless of lens wearing. However, Etafilcon A (0.57 +/- 0.09 microg/lens) showed more group IIa sPLA2 deposition than Polymacon (0.01 +/- 0.01 microg/lens; P < 0.001). Furthermore, group IIa sPLA2 deposited on Etafilcon A but not on Polymacon lenses retained its enzymatic activity. Significant differences of group IIa sPLA2 deposition were found in the 2 lenses tested. Such deposition might induce phospholipid hydrolysis in tears and thereby promote tear film instability in hydrophilic contact lens wearers.

Stabilization of neoclassical tearing modes by electron cyclotron current drive in JT-60U

International Nuclear Information System (INIS)

Isayama, A.; Oyama, N.; Urano, H.; Suzuki, T.; Takechi, M.; Hayashi, N.; Nagasaki, K.; Kamada, Y.; Ide, S.; Ozeki, T.

2007-01-01

Results of active control of neoclassical tearing modes (NTMs) by electron cyclotron current drive (ECCD) in JT-60U are described. Growth of an NTM with poloidal mode number m = 3 and toroidal mode number n = 2 has been suppressed by ECCD inside the sawtooth inversion radius in the co-direction, showing the possibility of the coexistence of sawtooth oscillations and a small-amplitude m/n = 3/2 NTM without large confinement degradation. Stabilization of an m/n = 2/1 NTM by ECCD at the mode rational surface has been demonstrated with a small ratio of the current density driven by the electron cyclotron (EC) wave to the local bootstrap current density (∼ 0.5). In addition, dependence of the stabilization effect on ECCD location has been investigated in detail. It has been found that an m/n = 2/1 NTM can be completely stabilized with the misalignment of the ECCD location less than about half of the full island width, and that the m/n = 2/1 NTM is destabilized with the misalignment comparable to the full island width. Time-dependent, self-consistent simulation of magnetic island evolution using the TOPICS code has shown that the stabilization and destabilization of an m/n = 2/1 NTM are well reproduced with the same set of coefficients of the modified Rutherford equation. The TOPICS simulation has also clarified that EC wave power required for complete stabilization can be significantly reduced by narrowing the ECCD deposition width

Convective transport and stability in films of binary mixtures

OpenAIRE

Madruga Sánchez, Santiago; Bribesh, Fathi; Uwe, Thiele

2011-01-01

Thin polymer films are increasingly used in advanced technological applications. The use of these films as coatings is often limited by their lack of stability due to their wettability properties on the substrates

Ocular symptoms and tear film break up time (BUT) among junior high school students in Penang, Malaysia - Associations with fungal DNA in school dust.

Science.gov (United States)

Norbäck, Dan; Hashim, Jamal Hisham; Hashim, Zailina; Sooria, Vinoshini; Ismail, Syazwan Aizat; Wieslander, Gunilla

2017-06-01

There are few studies on ocular effects of indoor mould exposure in schools, especially in the tropics OBJECTIVE: To study associations between eye symptoms and tear film break up time (BUT) in students and demographic data and fungal DNA in schools. A school environment study was performed among randomly selected students in eight randomly selected secondary schools in Penang, Malaysia. Information on eye symptoms and demographic data was collected by a standardised questionnaire. BUT was measured by two methods, self-reported BUT (SBUT) and by the non-invasive Tearscope (NIBUT). Dust was collected by vacuuming in 32 classrooms and analysed for five fungal DNA sequences. Geometric mean (GM) for total fungal DNA was 7.31*10 4 target copies per gram dust and for Aspergillus/Penicillium DNA 3.34*10 4 target copies per gram dust. Linear mixed models and 3-level multiple logistic regression were applied adjusting for demographic factors. A total of 368 students (58%) participated and 17.4% reported weekly eye symptoms the last 3 months. The median SBUT and TBUT were 15 and 12s, respectively. Students wearing glasses (OR 2.41, p=0.01) and with a history of atopy (OR=2.67; p=0.008) had more eye symptoms. Girls had less eye symptoms than boys (OR=0.34; p=0.006) Indoor carbon dioxide in the classrooms was low (range 380-720ppm), temperature was 25-30°C and relative air humidity 70-88%. Total fungal DNA in vacuumed dust was associated with shorter SBUT (4s shorter per 10 5 target copies per gram dust; p=0.04) and NIBUT (4s shorter per 10 5 target copies per gram dust; p<0.001). Aspergillus/Penicillium DNA was associated with shorter NIBUT (5s shorter per 10 5 target copies per gram dust; p=0.01). Fungal contamination in schools in a tropical country can be a risk factor for impaired tear film stability among students. Copyright © 2017 Elsevier GmbH. All rights reserved.

Cytokine changes in tears and relationship to contact lens discomfort.

Science.gov (United States)

Willcox, Mark D P; Zhao, Zhenjun; Naduvilath, Thomas; Lazon de la Jara, Percy

2015-01-01

To determine the reproducibility of a multiplex bead assay for measuring cytokines in tears and correlations between ocular discomfort with or without contact lens wear and the concentration of cytokines in tears. Ninety participants (divided into two groups) were enrolled in this prospective study. They were asked to rate their ocular comfort and collect their tears in the morning and just before sleep for 10 days with or without contact lenses. The participants collected their tears using a glass microcapillary tube for both stages. Galyfilcon A lenses were worn on a daily disposable basis during the contact lens stage, and comfort scores and tears were collected before lens insertion and prior to lens removal at the end of the day. Tears were analyzed for cytokine concentrations using a 27-plex multibead assay. Correlations were sought between cytokine concentrations and comfort. There was a significant (p-0.5 Log pg/ml, p-0.2 Log pg/ml, ptears was correlated to ocular comfort, but this was not changed by contact lens wear. Ocular comfort during the day is magnified by contact lens wear. However, the increase in the change in comfort during lens wear was not associated with changes in 15 cytokines in the tear film.

Avaliação da microbiota ocular em pacientes com disfunção do filme lacrimal Evaluation of conjunctival flora in patients with tear film dysfunction

Directory of Open Access Journals (Sweden)

Melissa Megumi Tomimatsu

2009-12-01

Full Text Available OBJETIVO: Avaliar a microbiota conjuntival em olhos com disfunção do filme lacrimal, e a modificação desta microbiota após a colocação de plug de silicone no canalículo inferior. MÉTODOS: Série de casos intervencionais não comparativos para avaliar 68 olhos de 41 pacientes com disfunção do filme lacrimal, durante o período de 2002 a 2007, na Universidade Federal de São Paulo. Todos os pacientes foram submetidos à colheita de amostras de raspado conjuntival de fundo-de-saco inferior para cultivo em Brain heart infusion broth. Os vinte e dois pacientes submetidos à colocação de plug de silicone repetiram a colheita de raspado conjuntival um mês após o procedimento. RESULTADOS: Dos 68 olhos avaliados, 47 apresentaram crescimento bacteriano nas amostras colhidas. Nove diferentes espécies de bactérias foram identificadas: Staphylococcus coagulase negativa em 66,66%, Staphylococcus aureus em 13,72%, Corynebacterium sp em 5,86%, Enterobacter aerogenes em 3,92%, Streptococcus hemolítico do grupo viridans em 1,96%, Serratia sp em 1,96%, Alcaligenes xylosoxidans spp em 1,96%, Corynebacterium xerosis em 1,96%, e Proteus mirabilis em 1,96%. Staphylococcus coagulase negativa (SCN foi o microrganismo mais frequentemente isolado tanto antes quanto após o plug de silicone. A sensibilidade do SCN à Oxacilina antes da colocação do plug era de 87,50%, e, após, de 73,68%. CONCLUSÃO: A microbiota em olhos com disfunção do filme lacrimal é bastante semelhante à encontrada em olhos normais. A resistência de SCN à Oxacilina foi um pouco maior após o implante do plug de silicone.PURPOSE: To evaluate conjunctival microbiota in eyes with tear film dysfunction and its modification after punctal occlusion with silicone plug. METHODS: Non comparative interventional case series study to evaluate 68 eyes of 41 patients with tear film dysfunction, from 2002 to 2007, followed in Federal University of Sao Paulo. Samples for culture were all

Real-time control of tearing modes using a line-of-sight electron cyclotron emission diagnostic

International Nuclear Information System (INIS)

Hennen, B A; Westerhof, E; De Baar, M R; Bongers, W A; Thoen, D J; Nuij, P W J M; Steinbuch, M; Oosterbeek, J W; Buerger, A

2010-01-01

The stability and performance of tokamak plasmas are limited by instabilities such as neoclassical tearing modes. This paper reports on an experimental proof of principle of a feedback control approach for real-time, autonomous suppression and stabilization of tearing modes in a tokamak. The system combines an electron cyclotron emission diagnostic for sensing of the tearing modes in the same sight line with a steerable electron cyclotron resonance heating and current drive (ECRH/ECCD) antenna. A methodology for fast detection of q = m/n = 2/1 tearing modes and retrieval of their location, rotation frequency and phase is presented. Set-points to establish alignment of the ECRH/ECCD deposition location with the centre of the tearing mode are generated in real time and forwarded in closed loop to the steerable launcher and as a modulation pulse train to the gyrotron. Experimental results demonstrate the capability of the control system to track externally perturbed tearing modes in real time.

The hip fluid seal--Part II: The effect of an acetabular labral tear, repair, resection, and reconstruction on hip stability to distraction.

Science.gov (United States)

Nepple, Jeffrey J; Philippon, Marc J; Campbell, Kevin J; Dornan, Grant J; Jansson, Kyle S; LaPrade, Robert F; Wijdicks, Coen A

2014-04-01

The acetabular labrum is theorized to be important to normal hip function by providing stability to distraction forces through the suction effect of the hip fluid seal. The purpose of this study was to determine the relative contributions of the hip capsule and labrum to the distractive stability of the hip, and to characterize hip stability to distraction forces in six labral conditions: intact labrum, labral tear, labral repair (looped vs. through sutures), partial resection, labral reconstruction with iliotibial band, and complete resection. Eight cadaveric hips with a mean age of 47.8 years (SD 4.3, range 41-51 years) were included. For each condition, the hip seal was broken by distracting the hip at a rate of 0.33 mm/s while the required force, energy, and negative intra-articular pressure were measured. For comparisons between labral conditions, measurements were normalized to the intact labral state (percent of intact). The relative contribution of the labrum to distractive stability was greatest at 1 and 2 mm of displacement, where it was significantly greater than the role of the capsule and accounted for 77 % (SD 27 %, p = 0.006) and 70 % (SD 7 %, p = 0.009) of total distractive stability, respectively. The relative contribution of the capsule to distractive stability increased with progressive displacement, providing 41 % (SD 49 %) and 52 % (SD 53 %) of distractive stability at 3 and 5 mm of distraction, respectively. The maximal distraction force required to break the hip seal in the intact labral state (capsule removed) varied from 124 to 150 N. Labral tear, partial resection, and complete resection resulted in average maximal distraction forces of 76 % (SD 34 %), 29 % (SD 26 %), and 27 % (SD 22 %), respectively, compared to the intact state. Through type labral repairs resulted in significantly greater improvements (from the labral tear state) in maximal negative pressure generated, compared to looped type repairs (median increase; +32 vs. -9 %, p

Effects of toroidal coupling on the stability of tearing modes

International Nuclear Information System (INIS)

Carreras, B.; Hicks, H.R.; Lee, D.K.

1980-06-01

The time evolution of tearing modes in toroidal geometry is studied in the low-β and large aspect ratio limit. An initial value three-dimensional computer code, which numerically advances the reduced set of resistive magnetohydrodynamic equations is employed. Toroidicity has, in general, a destabilizing effect on tearing modes in this limit. A generalization of the Δ' formalism can be used to study the linear regime. The results obtained in this way are in very good agreement with the results from the initial value code. The nonlinear phase of the evolution is also followed numerically. In the case of strong interaction of different helicities, a larger region of stochastic magnetic field lines results than in the cylindrical geometry case

Analysis of resistive tearing-mode in the reversed-field pinch plasma

International Nuclear Information System (INIS)

Oshiyama, Hiroshi; Masamune, Sadao; Hamuro, Eitaro; Tamaki, Reiji.

1985-01-01

As one of the methods of confining high temperature plasma by magnetic stress, attention has been paid to reversed field pinch (RFP). This RFP is the method of maintaining plasma pressure by combining the poloidal field generated by plasma current and the toroidal field having nearly same intensity, thus forming the toroidal shape, closed magnetic surface. As the typical RFP equipment, there have been TPE-1R(M), HBTX-1A, ZT-40M and OHTE, but in order to anticipate the further development, one of the problems is the resistive instability. In this study, the critical beta value determined by the tearing mode in RFP configuration was examined by analytical and numerical calculation methods. The position of a wall required for the stability was determined by solving a second order differential equation for a radial perturbed magnetic field. The propriety of the computer code for determining the position was examined. The magnetic field configuration having a finite beta value was determined, and its stability against a tearing mode was investigated. For this judgement of the stability, the developed computer code was used. The tearing mode in a Bessel function model, the tearing mode of a finite beta value and others are described. (Kako, I.)

Linear stability of liquid films with phase change at the interface

International Nuclear Information System (INIS)

Spindler, Bertrand

1980-01-01

The objective of this research thesis is to study the linear stability of the flow of a liquid film on an inclined plane with a heat flow on the wall and an interfacial phase change, and to highlight the influence of the phase change on the flow stability. In order to do so, the author first proposed a rational simplification of equations by studying the order of magnitude of different terms, and based on some simple hypotheses regarding flow physics. Two stability studies are then addressed, one regarding a flow with a pre-existing film, and the other regarding the flow of a condensation film. In both cases, it is assumed that there is no imposed heat flow, but that the driving effect of vapour by the liquid film is taken into account [fr

Requirements for alignment of electron cyclotron current drive for neoclassical tearing mode stabilization in ITER

International Nuclear Information System (INIS)

La Haye, R.J.; Ferron, J.R.; Humphreys, D.A.; Luce, T.C.; Petty, C.C.; Prater, R.; Strait, E.J.; Welander, A.S.

2008-01-01

ITER will rely on electron cyclotron stabilization of neoclassical tearing mode islands. The large size and low torque applied in ITER imply slow plasma rotation and susceptibility to island locking by the resistive wall; locking is likely to lead to a loss of the high confinement H-mode, a beta collapse and possibly disruption. 'Front' steering of the launcher, with narrower electron cyclotron current drive (ECCD), has resolved the issue in 'remote' steering of the driven current being too broad and relatively ineffective. However, narrower current drive places demands on alignment of the current drive on the rational surface that is being stabilized. DIII-D alignment techniques with and without (preemptive) an island are reviewed. The results are used to check models for the effect of misalignment and are then applied to ITER. Criteria for accuracy of alignment as a function of injected power and for the necessary time response of the controller are presented

Stability of tetraphenyl butadiene thin films in liquid xenon

International Nuclear Information System (INIS)

Sanguino, P.; Balau, F.; Botelho do Rego, A.M.; Pereira, A.; Chepel, V.

2016-01-01

Tetraphenyl butadiene (TPB) is widely used in particle detectors as a wavelength shifter. In this work we studied the stability of TPB thin films when immersed in liquid xenon (LXe). The thin films were deposited on glass and quartz substrates by thermal evaporation. Morphological and chemical surface properties were monitored before and after immersion into LXe by scanning electron microscopy and X-ray photoelectron spectroscopy. No appreciable changes have been detected with these two methods. Grain size and surface chemical composition were found to be identical before and after submersion into LXe. However, the film thickness, measured via optical transmission in the ultraviolet–visible wavelength regions, decreased by 1.6 μg/cm 2 (24%) after immersion in LXe during 20 h. These results suggest the necessity of using a protective thin film over the Tetraphenyl butadiene when used as a wavelength shifter in LXe particle detectors. - Highlights: • Stability of tetraphenyl butadiene (TPB) thin films immersed in liquid xenon (LXe). • Thermally evaporated TPB thin films were immersed in LXe for 20 h. • Film morphology and chemical surface properties remained unchanged. • Surface density of the films decreased by 1.6 μg/cm 2 (24%) after immersion in LXe. • For using in LXe particle detectors, TPB films should be protected with a coating.

High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

International Nuclear Information System (INIS)

Lee, Ching-Ting; Lin, Yung-Hao; Lin, Jhong-Ham

2015-01-01

Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance g m change, threshold voltage V T change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature

High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

Energy Technology Data Exchange (ETDEWEB)

Lee, Ching-Ting, E-mail: ctlee@ee.ncku.edu.tw; Lin, Yung-Hao; Lin, Jhong-Ham [Institute of Microelectronics, Department of Electrical Engineering, Research Center for Energy Technology and Strategy (RCETS), National Cheng Kung University, Tainan, Taiwan (China)

2015-01-28

Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance g{sub m} change, threshold voltage V{sub T} change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature.

[Effects of acupuncture on lactoferrin content in tears and tear secretion in patients suffering from dry eyes: a randomized controlled trial].

Science.gov (United States)

Shi, Jing-lin; Miao, Wan-hong

2012-09-01

With the understanding of the immune inflammatory response in the pathogenesis of dry eyes, and the limitations of widely used artificial tears and numerous pharmaceuticals and methods to promote tear secretion, clinicians pay more attention to the therapies that can promote tear secretion actively. Acupuncture treatment for dry eye may meet this requirement. To observe the clinical efficacy of acupuncture treatment on dry eye and the effects on duration, and to examine the mechanisms of acupuncture in treating patients with dye eyes. The study was performed at Department of Ophthalmology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine from August 2010 to May 2011. Patients with the primary diagnosis of dry eye were enrolled. Sixty-five patients were randomly divided into treatment group and control group, and were given 3 weeks of acupuncture treatment or artificial tear therapy respectively. The enzyme-linked immunosorbent assay was used to detect the lactoferrin content of the tears before and after treatment. In order to evaluate the efficacy of the treatment methods, the Schirmer I test and break-up time were also measured. Compared with before treatment, the lactoferrin content in the tears of patients in the treatment group increased, break-up time was prolonged and the result of the Schirmer I test showed improvement after 3 weeks of treatment. The indexes mentioned above did not change in the control group after treatment. There were no significant differences in tear lactoferrin and Schirmer I test between one week after treatment and after 3-week treatment in the treatment group, but break-up time was significantly shortened. The result of Schirmer I test in the treatment group was significantly higher than that in the control group one week after treatment. Acupuncture can increase tear lactoferrin level, extend tear film break-up time and promote tear secretion in patients with dry eye in a time-limited trial. With the end of

A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye

KAUST Repository

Gaffney, E.A.; Tiffany, J.M.; Yokoi, N.; Bron, A.J.

2010-01-01

Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model

Evaporation and Hydrocarbon Chain Conformation of Surface Lipid Films

Science.gov (United States)

Sledge, Samiyyah M.; Khimji, Hussain; Borchman, Douglas; Oliver, Alexandria; Michael, Heidi; Dennis, Emily K.; Gerlach, Dylan; Bhola, Rahul; Stephen, Elsa

2016-01-01

Purpose The inhibition of the rate of evaporation (Revap) by surface lipids is relevant to reservoirs and dry eye. Our aim was to test the idea that lipid surface films inhibit Revap. Methods Revap were determined gravimetrically. Hydrocarbon chain conformation and structure were measured using a Raman microscope. Six 1-hydroxyl hydrocarbons (11–24 carbons in length) and human meibum were studied. Reflex tears were obtained from a 62-year-old male. Results The Raman scattering intensity of the lipid film deviated by about 7 % for hydroxyl lipids and varied by 21 % for meibum films across the entire film at a resolution of 5 µm2. All of the surface lipids were ordered. Revap of the shorter chain hydroxyl lipids were slightly (7%) but significantly lower compared with the longer chain hydroxyl lipids. Revap of both groups was essentially similar to that of buffer. A hydroxyl lipid film did not influence Revap over an estimated average thickness range of 0.69 to >6.9 µm. Revap of human tears and buffer with and without human meibum (34.4 µm thick) was not significantly different. Revap of human tears was not significantly different from buffer. Conclusions Human meibum and hydroxyl lipids, regardless of their fluidity, chain length, or thickness did not inhibit Revap of buffer or tears even though they completely covered the surface. It is unlikely that hydroxyl lipids can be used to inhibit Revap of reservoirs. Our data do not support the widely accepted (yet unconfirmed) idea that the tear film lipid layer inhibits Revap of tears. PMID:27395776

Stability of Tl-Ba-Ca-Cu-O Superconducting Thin Films

Energy Technology Data Exchange (ETDEWEB)

Siegal, M.P.; Overmyer, D.L.; Venturini, E.L.; Padilla, R.R.; Provencio, P.N.

1999-08-23

We report the stability of TlBa{sub 2}CaCu{sub 2}O{sub 7} (Tl-1212) and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} (T1-2212) thin films and by inference, the stability of TlBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 9} (Tl-1223) and Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Tl-2223) thin films, under a variety of conditions. In general, we observe that the stability behavior of the single Tl-O layer materials (Tl-1212 and Tl-1223)are similar and the double Tl-O layer materials (Tl-2212 and Tl-2223) are similar. All films are stable with repeated thermal cycling to cryogenic temperatures. Films are also stable in acetone and methanol. Moisture degrades film quality rapidly, especially in the form of vapor. Tl-1212 is more sensitive to vapor than Tl-2212. These materials are stable to high temperatures in either N{sub 2}, similar to vacuum for the cuprates, and O{sub 2} ambients. While total degradation of properties (superconducting and structural) occur at the same temperatures for all phases, 600 C in N{sub 2} and 700 C in O{sub 2}, the onset of degradation occurs at somewhat lower temperatures for Tl-1212 than for Tl-2212 films. In all cases, sample degradation is associated with Tl depletion from the films.

As tears go by : Baby tears trigger more brain activity than adult tears in nulliparous women

NARCIS (Netherlands)

Hendricx-Riem, M.M.E.; De Carli, P.; van IJzendoorn, M.H.; Vingerhoets, A.J.J.M.; Bakermans-Kranenburg, M.J.

2017-01-01

The current functional magnetic resonance imaging study examines brain activity during the perception of infant and adult tears. Infant tears evoke stronger responses in the visual cortex than adult tears, indicating that infant tears are highly salient. In addition, our study shows that infant

SLAP tears of the glenoid labrum in contact athletes.

Science.gov (United States)

Funk, Lennard; Snow, Martyn

2007-01-01

To describe the distribution and clinical presentation of labral injuries in rugby players and the time taken for them to return to sports. Retrospective cohort study. Busy shoulder practice in the North West of England, treating a large number of professional athletes. A review of 51 shoulder arthroscopies performed on professional rugby players over a 35 month period. All patients diagnosed with a SLAP lesion at arthroscopy were identified. Eighteen patients had a documented SLAP tear; this group represented our study population. Arthroscopic debridement and/or stabilization was carried out for all labral injuries using Panaloc anchors and No. 2 PDS via a 2 portal technique. Classification of injury, Satisfaction, Time to return to play. The incidence of SLAP tears in our study population was 35%. There were 11 isolated SLAP tears (61%), 3 SLAP tears associated with a Bankart lesion (17%), 2 SLAP tears associated with a posterior labral lesion (11%), and 2 SLAP tears associated with an anterior and posterior labral injuries (11%). Of the 18 SLAP tears, 14 (78%) were type 2, 3 (17%) were type 3, and 1 (5%) was type 4. None of the patients with a SLAP tear presented with symptoms of instability. MR Arthrogram had a 76% sensitivity for detecting SLAP tears. By 6 months postsurgery, 89% of patients were satisfied. Patients with isolated SLAP tears were the quickest to return to sports, at an average of 2.6 months postsurgery. SLAP tears are a common injury in rugby players. These can often be diagnosed with MR arthrography. Arthroscopic repair is associated with excellent results and early return to sports.

Tears Falling on Goosebumps: Co-occurrence of Emotional Lacrimation and Emotional Piloerection Indicates a Psychophysiological Climax in Emotional Arousal

Science.gov (United States)

Wassiliwizky, Eugen; Jacobsen, Thomas; Heinrich, Jan; Schneiderbauer, Manuel; Menninghaus, Winfried

2017-01-01

This psychophysiological study is the first to examine the relationship between emotional tears and emotional piloerection (i.e., goosebumps). Although both phenomena have been related to peak states of being moved, details about their temporal occurrence and the associated levels of physiological arousal have remained unknown. In our study, we used emotionally powerful film scenes that were self-selected by participants. Our findings show that even within peak moments of emotional arousal, a gradation of intensity is possible. The overlap of tears and goosebumps signifies a maximal climax within peak moments. On the side of the stimulus, we found that displays of prosocial behavior play a crucial role in the elicitation of tears and goosebumps. Finally, based on the results of a formal film analysis of the tears-eliciting clips provided by our participants, as compared to randomly extracted, equally long control clips from the same films, we show how the technical and artistic making of the clips was optimized for the display of social interaction and emotional expressions. PMID:28223946

Contact geometry at the undersurface of the acromion with and without a rotator cuff tear.

Science.gov (United States)

Lee, S B; Itoi, E; O'Driscoll, S W; An, K N

2001-04-01

The purpose of this study was to investigate the difference in contact geometry at the undersurface of acromion in shoulders with and without a rotator cuff (RC) tear. Case-control study. Forty fresh cadaveric shoulders (average age at death, 61 years) without gross osteoarthritic changes were divided into the intact RC group (n = 20) and the RC tear group (n = 20). Clinical impingement was simulated by compressing the humeral head and the intact portion of the RC against the coracoacromial arch with an axial compressive force of 25 kg while the humerus was held abducted 20 degrees in the scapular plane. The contact pattern between the acromion and the RC was measured with Fuji Prescale super low-pressure-sensitive film (Fuji Photo Film Co, Ltd, Tokyo, Japan). The imprint image was analyzed using Global Lab image software (Automatix, Marlboro, MA). The percentage of the maximum anteroposterior dimension of the imprint on Fuji film to the anteroposterior diameter of the acromial undersurface was 29% +/- 9% in intact RC shoulders, and 39% +/- 13% in shoulders with an RC tear (P >.05). The percentage of the maximum mediolateral dimension of the imprint to the mediolateral diameter of the corresponding part of the acromial undersurface was 27% +/- 12% in intact RC shoulders, and 48% +/- 11% in shoulders with an RC tear. This difference was statistically significant (P RC in the anteroposterior dimension, which might be related to the appearance in supraspinatus outlet view, was not significantly different between shoulders with and without an RC tear. These findings suggest that factors other than acromial shape play a significant role in the pathogenesis of RC tears. The implication regarding the role of acromioplasty remains to be clarified.

Aspergillus flavus induced alterations in tear protein profile reveal pathogen-induced host response to fungal infection.

Science.gov (United States)

Kandhavelu, Jeyalakshmi; Demonte, Naveen Luke; Namperumalsamy, Venkatesh Prajna; Prajna, Lalitha; Thangavel, Chitra; Jayapal, Jeya Maheshwari; Kuppamuthu, Dharmalingam

2017-01-30

Aspergillus flavus and Fusarium sp. are primary causative agents of keratitis that results in corneal tissue damage leading to vision loss particularly in individuals from the tropical parts of the world. Proteins in the tear film collected from control and keratitis patients was profiled and compared. A total of 1873 proteins from control and 1400 proteins from patient tear were identified by mass spectrometry. While 847 proteins were found to be glycosylated in the patient tear, only 726 were glycosylated in control tear. And, some of the tear proteins showed alterations in their glycosylation pattern after infection. Complement system proteins, proteins specific for neutrophil extracellular traps and proteins involved in would healing were found only in the patient tear. The presence of these innate immune system proteins in the tear film of patients supports the previous data indicating the involvement of neutrophil and complement pathways in antifungal defense. High levels of wound healing proteins in keratitis patient tear implied activation of tissue repair during infection. The early appearance of the host defense proteins and wound healing response indicates that tear proteins could be used as an early marker system for monitoring the progression of pathogenesis. Identification of negative regulators of the above defense pathways in keratitis tear indicates an intricate balance of pro and anti-defense mechanisms operating in fungal infection of the eye. Tear proteins from control and mycotic keratitis patients were separated into glycoproteins and non-glycosylated proteins and then identified by mass spectrometry. Tear proteins from keratitis patients showed alteration in the glycosylation pattern indicating the alteration of glycosylation machinery due to infection. Neutrophil extracellular traps specific proteins, complement pathway proteins, as well as wound healing proteins, were found only in patient tear showing the activation of antifungal defense

Nucleation and strain-stabilization during organic semiconductor thin film deposition.

Science.gov (United States)

Li, Yang; Wan, Jing; Smilgies, Detlef-M; Bouffard, Nicole; Sun, Richard; Headrick, Randall L

2016-09-07

The nucleation mechanisms during solution deposition of organic semiconductor thin films determine the grain morphology and may influence the crystalline packing in some cases. Here, in-situ optical spectromicroscopy in reflection mode is used to study the growth mechanisms and thermal stability of 6,13-bis(trisopropylsilylethynyl)-pentacene thin films. The results show that the films form in a supersaturated state before transforming to a solid film. Molecular aggregates corresponding to subcritical nuclei in the crystallization process are inferred from optical spectroscopy measurements of the supersaturated region. Strain-free solid films exhibit a temperature-dependent blue shift of optical absorption peaks due to a continuous thermally driven change of the crystalline packing. As crystalline films are cooled to ambient temperature they become strained although cracking of thicker films is observed, which allows the strain to partially relax. Below a critical thickness, cracking is not observed and grazing incidence X-ray diffraction measurements confirm that the thinnest films are constrained to the lattice constants corresponding to the temperature at which they were deposited. Optical spectroscopy results show that the transition temperature between Form I (room temperature phase) and Form II (high temperature phase) depends on the film thickness, and that Form I can also be strain-stabilized up to 135 °C.

Diblock Copolymer/Layered Silicate Nanocomposite Thin Film Stability

Science.gov (United States)

Limary, Ratchana; Green, Peter

2000-03-01

The stability of thin film symmetric diblock copolymers blended with layered silicate nanocomposites were examined using a combination of optical microscopy, atomic force microscopy (AFM), and X-ray diffraction (XRD). Two cases were examined PS-b-PMMA (polystyrene-b-polymethylacrylate) blended with montmorillonite stoichiometrically loaded with alkyl ammonium ions, OLS(S), and PS-b-PMMA blended with montmorillonite loaded with excess alkyl ammonium ions, OLS(E). XRD spectra show an increase in the gallery spacing of the OLSs, indicating that the copolymer chains have intercalated the layered silicates. AFM images reveal a distinct difference between the two nanocomposite thin films: regions in the vicinity of OLS(S) aggregates were depleted of material, while in the vicinity of OLS(E) aggregates, dewetting of the substrate occurred. We show that the stability of the copolymer/OLS nanocomposite films is determined by the enthalpic driving force associated with intercalation of the copolymer chains into the galleries of the modified OLS layers and by the substrate/organic modifier interactions.

Stability of thin liquid films containing surface active particles

Science.gov (United States)

Umashankar, Hariharan; Kalpathy, Sreeram; Dixit, Harish

2017-11-01

The stability and dynamics of thin liquid films(industrial settings like coating and printing processes and extraction of oil from porous rocks. In this study a hydrodynamic model is introduced to capture the long term evolution of a Newtonian liquid film containing insoluble surfaceactive particles.We consider here the possibility of four distinct interaction regimes based on the surface rheological effects of the particles, such that either, both or neither of Marangoni and surface viscosity effects would be present at the leading order in the governing equations. The liquid film is bounded by a rigid impermeable solid below and covered by passive air phase above.A standard linear stability analysis and nonlinear simulations are performed on the set of highly coupled partial differential evolution equations. Linear stability analysis gives insights on whether a particular imposed perturbationwavenumber will grow or decay in time and also evaluating the fastest growing wavenumber. Parametric studies for all four regimes provides a strong confirmation that surface viscosity and Marangoni effects are indeed rupture delaying effects.

Novel Nano-Liposome Formulation for Dry Eyes with Components Similar to the Preocular Tear Film

Directory of Open Access Journals (Sweden)

Marta Vicario-de-la-Torre

2018-04-01

Full Text Available Dry eye is commonly treated with artificial tears; however, developing artificial tears similar to natural tears is difficult due to the complex nature of tears. We characterized and evaluated a novel artificial tear formulation with components similar to the lipid and aqueous constituents of natural tears. Nano-liposomes, composed in part of phosphatidylcholine, were dispersed in an aqueous solution of bioadhesive sodium hyaluronate. Liposome size, zeta potential, and physicochemical properties of the fresh and stored (4 °C liposomal formulation were analyzed. In vitro tolerance was tested using human corneal and conjunctival cell lines by exposures of 15 min to 4 h. The tolerance of the liposomal formulation was evaluated in animals (rabbits. The average liposome size was 186.3 ± 7.0 nm, and the zeta potential was negative. The osmolarity of the formulation was 198.6 ± 1.7 mOsm, with a surface tension of 36.5 ± 0.4 mN/m and viscosity of 3.05 ± 0.02 mPa·s. Viability values in the human corneal and conjunctival cell lines were always >80%, even after liposomal formulation storage for 8 weeks. Discomfort and clinical signs after instillation in rabbit eyes were absent. The new formulation, based on phosphatidylcholine-liposomes dispersed in sodium hyaluronate has suitable components and characteristics, including high in vitro cell viability and good in vivo tolerance, to serve as a tear substitute.

Prospects for stabilization of neoclassical tearing modes by electron cyclotron current drive in ITER

International Nuclear Information System (INIS)

La Haye, R.J.; Isayama, A.; Maraschek, M.

2009-01-01

The system planned for electron cyclotron current drive (ECCD) in ITER can mitigate the deleterious effects of neoclassical tearing modes (NTMs) provided that either adequate alignment of the ECCD to the rational surface is maintained or too large a misalignment is corrected on a time scale shorter than the deleterious plasma response to 'large' islands. Resistive neoclassical tearing modes will be the principal limit on stability and performance in the ITER standard scenario as the drag from rotating island induced eddy current in the resistive wall (particularly from the m/n = 2/1 mode) can slow the plasma rotation, produce locking to the wall and cause loss of high-confinement H-mode and disruption. Continuous wave (cw) ECCD at the island rational surface is successful in stabilization and/or prevention of NTMs in ASDEX Upgrade, DIII-D and JT-60U. Modulating the ECCD so that it is absorbed only on the rotating island O-point is proving successful in recovering effectiveness in ASDEX Upgrade when the ECCD is configured for wider deposition as expected in ITER. The models for the effect of misalignment on ECCD effectiveness are applied to ITER. Tolerances for misalignment are presented to establish criteria for both the alignment (by moving mirrors in ITER) in the presence of an island, and for the accuracy of real-time ITER MHD equilibrium reconstruction in the absence of an island, i.e. alignment to the mode or to the rational surface in the absence of the mode. The narrower ECCD with front steering makes precise alignment more necessary for the most effective stabilization even though the ECCD is still relatively broad, with current density deposition (full width half maximum) almost twice the marginal island width. This places strict requirements on ECCD alignment with the expected ECCD effectiveness dropping to zero for misalignments as small as 1.7 cm. The system response time for growing islands and slowing rotation without and with ECCD (at different

Simulation of neoclassical tearing mode stabilization via minimum seeking method on ITER

Energy Technology Data Exchange (ETDEWEB)

Park, M. H.; Kim, K.; Na, D. H.; Byun, C. S.; Na, Y. S. [Seoul National Univ., Seoul (Korea, Republic of); Kim, M. [FNC Technology Co. Ltd, Yongin (Korea, Republic of)

2016-10-15

Neoclassical tearing modes (NTMs) are well known resistive magnetohydrodynamic (MHD) instabilities. These instabilities are sustained by a helically perturbed bootstrap current. NTMs produce magnetic islands in tokamak plasmas that can degrade confinement and lead to plasma disruption. Because of this, the stabilization of NTMs is one of the key issues for tokamaks that achieve high fusion performance such as ITER. Compensating for the lack of bootstrap current by an Electron Cyclotron Current Drive (ECCD) has been proved experimentally as an effective method to stabilize NTMs. In order to stabilize NTMs, it is important to reduce misalignment. So that even ECCD can destabilize the NTMs when misalignment is large. Feedback control method that does not fully require delicate and accurate real-time measurements and calculations, such as equilibrium reconstruction and EC ray-tracing, has also been proposed. One of the feedback control methods is minimum seeking method. This control method minimizes the island width by tuning the misalignment, assuming that the magnetic island width is a function of the misalignment. As a robust and simple method of controlling NTM, minimum 'island width growth rate' seeking control is purposed and compared with performance of minimum ' island width' seeking control. At the integrated numerical system, simulations of the NTM suppression are performed with two types of minimum seeking controllers; one is a FDM based minimum seeking controller and the other is a sinusoidal perturbation based minimum seeking method. The full suppression is achieved both types of controller. The controllers adjust poloidal angle of EC beam and reduce misalignment to zero. The sinusoidal perturbation based minimum seeking control need to modify the adaptive gain.

Agreement of non-invasive tear break up time measurement between Tomey RT-7000 Auto Refractor-Keratometer and Oculus Keratograph 5M

Directory of Open Access Journals (Sweden)

Lee R

2016-09-01

.Conclusion: While there are theoretical and practical benefits of NIBUT for assessment of tear stability over dye-based methods, the agreement between the two modalities was poor. Hence, studies and trials assessing NIBUT should avoid using these modalities interchangeably for NIBUT assessment. More research is needed to improve consensus on how to determine NIBUT. Keywords: tear break-up time, tear film, Oculus Keratograph, Tomey RT-7000, dry eye

Stability and modification of passive films of new PUREX-materials

International Nuclear Information System (INIS)

Schultze, J.W.; Siemensmeyer, B.; Patzelt, T.

1991-10-01

The valve metals Ti, Zr and others and their alloys can be used in nitric acid solutions of the Purex process. They are protected by passive films which are stable at least at low temperatures and concentrations. Electrochemical investigations and corrosion tests are applied to check improvements of the materials. Niobium can be used to substitute the very expensive tantalum. Electrochemical and analytical investigations show the formation of the corrosion stable oxide film. Special problems are treated, such as the stability of welded joints or the influence of radioactive irradiation. α-radiation and hot atoms are simulated by ion implantation, β- and γ-radiation are simulated by laser light. In both types of experiments no decrease of stability is indicated. The alloy Ti5Ta is more stable than Ti, but it is not as good as Ta. Other alloys of Ti were investigated, but they are not suitable for the Purex process. New protection layers are tested. With respect to their preparation as well as their corrosion stability, ANOF-films are promising, but TiN-films are not stable enough. (orig.) With 71 refs., 7 tabs., 71 figs [de

Investigating On Colour Stability Conditions Of Postirradiation Radiochromic Film Dosimeter

International Nuclear Information System (INIS)

Nguyen Nguyet Dieu; Doan Binh; Pham Thu Hong; Cao Van Chung; Nguyen Thanh Duoc

2011-01-01

B3 dosimeter is a thin film with average thickness of 0.0194 mm, which is supplied by the Gex company, the United States. This dosimeter was influenced by many factors: light, temperature, humidity during and after irradiation process. In fact, B3 film dosimeters will be stable under certain conditions such as tightly sealed packs, controlled irradiation and stored temperature after irradiated. Therefore, investigation of the stability effect of postirradiated B3 film dosimeters on the heating temperature, heating time and storing time is carried out before the absorbed dose is read and followed standard reading procedures. When exposed to ionizing radiation, the dosimeters change from colorless to colour. The absorbed doses are read on a Genesys 20 spectrophotometer at a wavelength of 544 nm. Absorbed dose range is investigated from 0.55 to 80 kGy. Experimental results were indicated that colour stability of the postirradiated dosimeters at a temperature of 65 ± 3 o C for 30 minutes and keeping them in desiccator for 5 minutes before read out. Under these conditions, colour stability of B3 film dosimeter has maintained for 3 months. (author)

Proteases, proteolysis and inflammatory molecules in the tears of people with keratoconus.

Science.gov (United States)

Balasubramanian, Sivaraman Arumugam; Mohan, Sujatha; Pye, David Cecil; Willcox, Mark Duncan Perry

2012-06-01

To investigate the expression of proteases, proteolytic activity and cytokines in the tear film of people with keratoconus. Basal tears from people with keratoconus, from individuals who had undergone corneal collagen cross-linking for the treatment of keratoconus, and from normal controls were collected using a capillary tube. Corneal curvature of each subject was mapped. The total protein in tears was estimated. Levels and activity of proteases in the tears were analysed using specific antibody arrays and activity assays. The total tear protein level was significantly reduced in keratoconus (4.1 ± 0.9 mg/ml) compared with normals (6.7 ± 1.4 mg/ml) (p tear expression of matrix metalloproteinases (MMP) -1, -3, -7, -13, interleukins (IL) -4, -5, -6, -8 and tumour necrosis factor (TNF) -α, -β were evident in keratoconus. Tear IL-6 was the only cytokine significantly (p tears of keratoconus subjects compared with the collagen cross-linked group. No significant difference in tear proteases were observed between the normal and the cross-linked groups, although the expression of TNF-α was significantly (p tears from keratoconus compared with normal subjects. The activity of tear gelatinases (69.6 ± 22.2 FIU) and collagenases (5.7 ± 3.3 FIU) in the collagen cross-linked group was not significantly different compared with either keratoconus or normals. Tears of people with keratoconus had 1.9 times higher levels of proteolytic activity and over expression of several MMPs and cytokines compared with tears from controls. Further investigations are required to study the possible implications of these changes and whether they can be used to monitor disease progression or determine the success of corneal collagen cross-linking. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

High Stability Performance of Quinary Indium Gallium Zinc Aluminum Oxide Films and Thin-Film Transistors Deposited Using Vapor Cooling Condensation Method

Science.gov (United States)

Lin, Yung-Hao; Lee, Ching-Ting

2017-08-01

High-quality indium gallium zinc aluminum oxide (IGZAO) thin films with various Al contents have been deposited using the vapor cooling condensation method. The electron mobility of the IGZAO films was improved by 89.4% on adding Al cation to IGZO film. The change in the electron concentration and mobility of the IGZAO films was 7.3% and 7.0%, respectively, when the temperature was changed from 300 K to 225 K. These experimental results confirm the high performance and stability of the IGZAO films. The performance stability mechanisms of IGZAO thin-film transistors (TFTs) were investigated in comparison with IGZO TFTs.

Film packed lithium-ion battery with polymer stabilizer

International Nuclear Information System (INIS)

Satoh, Masaharu; Nakahara, Kentaro

2004-01-01

The 1600 mAh class of film packed lithium-ion battery has been fabricated with the polymer stabilizer. The adhesive polymer covered with fluorinated polymer beads enables to penetrate into the prismatically wounded jerry-roll layers and connects the electrode layers and separator film. The battery demonstrates the improved properties after repeating the charge and discharge processes and should be useful for the various electronics equipment such as notebook type computer

Numerical simulation of feedback stabilization of the tearing mode in a rotating plasma

International Nuclear Information System (INIS)

Speranskii, N.N.

1991-01-01

The suppression of the tearing mode by means of feedback is studied in a rotating plasma cylinder. The feedback is produced by a coil whose winding is specified by cos var-phi, var-phi = mθ - kz. It is shown that when a resonant surface is present in the rotating plasma the current in the feedback winding generates a magnetic flux in the plasma with cos var-phi and sin var-phi angular dependence. The processes of particle capture is explained. The rotational instability which arises because of the repulsion between the feedback and tearing-mode currents, which interferes with suppression of the tearing mode, is absent when the plasma rotates sufficiently rapidly. In this feedback dependence the form of the plasma current profile determines whether there can be an instability in the induced current resulting from the presence of the feedback

Anterior cruciate ligament tear: comparison of MR features between complete and partial tear

International Nuclear Information System (INIS)

Song, Ki Young; Lee, Joo Hyuk; Park, Jin Hee; Lee, Yu Jin; Rho, Eun Jin; Kim, Young Hoon; Yi, Jeong Geun; Ahn, Joong Mo

1997-01-01

To determine the MRI features which distinguish complete and partial tear of the anterior cruciate ligament(ACL) and to thus improve MRI interpretation. In 80 patients, we analyzed MR findings of direct and indirect signs of ACL tear (complete tear, 61 cases, partial tear, 19 cases) confirmed by arthroscopy or surgery, and compared the relative incidence of each sign in cases of complete and partial tear. Direct and indirect signs were found in 61 (100%) and 60 cases (98.4%), respectively, in complete tears, but in 16 (84.2%) and 15 cases (78.9%), respectively, in partial tears. Poor visualization, discontinuity and hyperintensity were seen in all complete tears but in only nine cases (47.4%) of partial tear. A wavy or abnormal contour was seen in 53 cases (86.9%) of complete tear and 14 (73.7%) of partial tear. A wavy contour without other direct signs was seen in only five cases (26.3%) of partial tear. Three cases (15.8%) of partial tear showed normal MR finding. Indirect signs, i.e. abnormal ACL angle, abnormal ACL-Blumensaat line angle, abnormal posterior cruciate ligament (PCL) line, abnormal PCL angle, PCL buckling, anterior displacement of tibia, posterior displacement of lateral meniscus, bone bruise, Segond fracture, tear of collateral ligaments, PCL, and tear of meniscus were commoner in complete than in partial tears. Two cases of O'Donoghue's triad and two of popliteus injury were seen only in complete tears. Direct and indirect signs of ACL tear were more commonly noted in complete than in partial tears. The latter showed MR features varying from normal to almost complete tear. We suggest that a wavy contour without other direct signs is indicative of a partial tear, and that O'Donoghue's triad and popliteus muscle injury are indirect signs of a complete tear

The Structure and Stability of Molybdenum Ditelluride Thin Films

Directory of Open Access Journals (Sweden)

Zhouling Wang

2014-01-01

Full Text Available Molybdenum-tellurium alloy thin films were fabricated by electron beam evaporation and the films were annealed in different conditions in N2 ambient. The hexagonal molybdenum ditelluride thin films with well crystallization annealed at 470°C or higher were obtained by solid state reactions. Thermal stability measurements indicate the formation of MoTe2 took place at about 350°C, and a subtle weight-loss was in the range between 30°C and 500°C. The evolution of the chemistry for Mo-Te thin films was performed to investigate the growth of the MoTe2 thin films free of any secondary phase. And the effect of other postdeposition treatments on the film characteristics was also investigated.

Mass spectrometric identification of phospholipids in human tears and tear lipocalin.

Science.gov (United States)

Dean, Austin W; Glasgow, Ben J

2012-04-02

The purpose of this article was to identify by mass spectrometry phosphocholine lipids in stimulated human tears and determine the molecules bound to tear lipocalin or other proteins. Tear proteins were separated isocratically from pooled stimulated human tears by gel filtration fast performance liquid chromatography. Separation of tear lipocalin was confirmed by SDS tricine gradient PAGE. Protein fractions were extracted with chloroform/methanol and analyzed with electrospray ionization MS/MS triple quadrupole mass spectrometry in precursor ion scan mode for select leaving groups. For quantification, integrated ion counts were derived from standard curves of authentic compounds of phosphatidylcholine (PC) and phosphatidylserine. Linear approximation was possible from integration of the mass spectrometrically obtained ion peaks at 760 Da for the PC standard. Tears contained 194 ng/mL of the major intact PC (34:2), m/z 758.6. Ten other monoisotopic phosphocholines were found in tears. A peak at 703.3 Da was assigned as a sphingomyelin. Four lysophosphatidylcholines (m/z 490-540) accounted for about 80% of the total integrated ion count. The [M+H](+) compound, m/z 496.3, accounted for 60% of the signal intensity. Only the tear lipocalin-bearing fractions showed phosphocholines (104 ng/mL). Although the intact phospholipids bound to tear lipocalin corresponded precisely in mass and relative signal intensity to that found in tears, we did not identify phosphocholines between m/z 490 and 540 in any of the gel-filtration fractions. Phospholipids, predominantly lysophospholipids, are present in tears. The higher mass intact PCs in tears are native ligands of tear lipocalin.

Effect of Graphene-EC on Ag NW-Based Transparent Film Heaters: Optimizing the Stability and Heat Dispersion of Films.

Science.gov (United States)

Cao, Minghui; Wang, Minqiang; Li, Le; Qiu, Hengwei; Yang, Zhi

2018-01-10

To optimize the performance of silver nanowire (Ag NW) film heaters and explore the effect of graphene on a film, we introduced poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and graphene modified with ethyl cellulose (graphene-EC) into the film. The high-quality and well-dispersed graphene-EC was synthesized from graphene obtained by electrochemical exfoliation as a precursor. The transparent film heaters were fabricated via spin-coating. With the assistance of graphene-EC, the stability of film heaters was greatly improved, and the conductivity was optimized by adjusting the Ag NW concentration. The film heaters exhibited a fast and accurate response to voltage, accompanied by excellent environmental endurance, and there was no significant performance degradation after being operated for a long period of time. These results indicate that graphene-EC plays a crucial role in optimizing film stability and heat dispersion in the film. The Ag NW/PEDOT:PSS-doped graphene-EC film heaters show a great potential in low-cost indium-tin-oxide-free flexible transparent electrodes, heating systems, and transparent film heaters.

Film packed lithium-ion battery with polymer stabilizer

Energy Technology Data Exchange (ETDEWEB)

Satoh, Masaharu; Nakahara, Kentaro [NEC Corp., Environment and Material Research Labs., Kawasaki, Kanagawa (Japan)

2004-11-30

The 1600 mAh class of film packed lithium-ion battery has been fabricated with the polymer stabilizer. The adhesive polymer covered with fluorinated polymer beads enables to penetrate into the prismatically wound jerry-roll layers and connects the electrode layers and separator film. The battery demonstrates the improved properties after repeating the charge and discharge processes and should be useful for the various electronic equipment such as notebook type computers. (Author)

Thermal propagation and stability in superconducting films

International Nuclear Information System (INIS)

Gray, K.E.; Kampwirth, R.T.; Zasadzinski, J.F.; Ducharme, S.P.

1983-01-01

Thermal propagation and stable hot spots (normal domains) are studied in various high Tsub(c) superconducting films (Nb 3 Sn, Nb, NbN and Nb 3 Ge). A new energy balance is shown to give reasonable quantitative agreement of the dependence of the propagation velocity on the length of short normal domains. The steady state (zero velocity) measurements indicate the existence of two distinct situations for films on high thermal conductivity (sapphire) substrates. For low power per unit area the film and substrate have the same temperature, and the thermal properties of the substrate dominate. However, for higher power densities in short hot spots, the coupling is relatively weak and the thermal properties of the film alone are important. Here a connection is made between the critical current stability of superconducting films and a critical hot spot size for thermal propagation. As a result efficient heat removal is shown to dominate the stabilisation of superconducting films. The strong and weak coupling situations also lead to modifications of the models for propagation velocities on sapphire substrates. Self-healing of hot spots and other phenomena in superconducting film are explained. The potential use of the thermal propagation model in applications of superconductors, especially switches is discussed. (author)

Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

Energy Technology Data Exchange (ETDEWEB)

Rahman, Md Taibur; McCloy, John; Panat, Rahul, E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99163 (United States); Ramana, C. V., E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)

2016-08-21

Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24–500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

International Nuclear Information System (INIS)

Rahman, Md Taibur; McCloy, John; Panat, Rahul; Ramana, C. V.

2016-01-01

Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24–500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

Science.gov (United States)

Rahman, Md Taibur; McCloy, John; Ramana, C. V.; Panat, Rahul

2016-08-01

Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24-500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

Influence of toroidal rotation on resistive tearing modes in tokamaks

International Nuclear Information System (INIS)

Wang, S.; Ma, Z. W.

2015-01-01

Influence of toroidal equilibrium plasma rotation on m/n = 2/1 resistive tearing modes is studied numerically using a 3D toroidal MHD code (CLT). It is found that the toroidal rotation with or without shear can suppress the tearing instability and the Coriolis effect in the toroidal geometry plays a dominant role on the rotation induced stabilization. For a high viscosity plasma (τ R /τ V  ≫ 1, where τ R and τ V represent resistive and viscous diffusion time, respectively), the effect of the rotation shear combined with the viscosity appears to be stabilizing. For a low viscosity plasmas (τ R /τ V  ≪ 1), the rotation shear shows a destabilizing effect when the rotation is large

Langmuir-Blodgett films of alkane chalcogenice (S, Se, Te) stabilized gold nanoparticles

DEFF Research Database (Denmark)

Brust, M.; Stuhr-Hansen, N.; Norgaard, K.

2001-01-01

Gold nanoparticles stabilized by alkanethiolates, alkaneselenides, and alkanetellurides have been prepared by analogous methods. Chloroform solutions of thiolate and selenide stabilized particles were spread and evaporated on the water/air interface where the particles formed well-defined Langmuir...... films. The films were transferred to solid supports of freshly cleaved mica and were studied by atomic force microscopy (AFM). The particles were found to have an average core diameter of 2 nm. The stability of the particles under ambient conditions increased in the order Te

Development of novel zein-sodium caseinate nanoparticle (ZP)-stabilized emulsion films for improved water barrier properties via emulsion/solvent evaporation.

Science.gov (United States)

Wang, Li-Juan; Yin, Ye-Chong; Yin, Shou-Wei; Yang, Xiao-Quan; Shi, Wei-Jian; Tang, Chuan-He; Wang, Jin-Mei

2013-11-20

This work attempted to develop novel high barrier zein/SC nanoparticle (ZP)-stabilized emulsion films through microfluidic emulsification (ZPE films) or in combination with solvent (ethyl acetate) evaporation techniques (ZPE-EA films). Some physical properties, including tensile and optical properties, water vapor permeability (WVP), and surface hydrophobicity, as well as the microstructure of ZP-stabilized emulsion films were evaluated and compared with SC emulsion (SCE) films. The emulsion/solvent evaporation approach reduced lipid droplets of ZP-stabilized emulsions, and lipid droplets of ZP-stabilized emulsions were similar to or slightly lower than that of SC emulsions. However, ZP- and SC-stabilized emulsion films exhibited a completely different microstructure, nanoscalar lipid droplets were homogeneously distributed in the ZPE film matrix and interpenetrating protein-oil complex networks occurred within ZPE-EA films, whereas SCE films presented a heterogeneous microstructure. The different stabilization mechanisms against creaming or coalescence during film formation accounted for the preceding discrepancy of the microstructures between ZP-and SC-stabilized emulsion films. Interestingly, ZP-stabilized emulsion films exhibited a better water barrier efficiency, and the WVP values were only 40-50% of SCE films. A schematic representation for the formation of ZP-stabilized emulsion films was proposed to relate the physical performance of the films with their microstructure and to elucidate the possible forming mechanism of the films.

A Special Tear Pattern of Anterior Horn of the Lateral Meniscus: Macerated Tear.

Science.gov (United States)

Zheng, Jiapeng; Zhai, Wenliang; Li, Qiang; Jia, Qianxin; Lin, Dasheng

2017-01-01

We describe a special, interesting phenomenon found in the anterior horn of the lateral meniscus (AHLM): most tear patterns in the AHLM are distinctive, with loose fibers in injured region and circumferential fiber bundles were separated. We name it as macerated tear. The goal of this study was to bring forward a new type of meniscal tear in the AHLM and investigate its clinical value. AHLM tears underwent arthroscopic surgery from January 2012 to December 2014 were included. Data regarding the integrity of AHLM were prospectively recorded in a data registry. Tear morphology and treatment received were subsequently extracted by 2 independent reviewers from operative notes and arthroscopic surgical photos. A total of 60 AHLM tears in 60 patients (mean age 27.1 years) were grouped into horizontal tears (n = 15, 25%), vertical tears (n = 14, 23%), complex tears (n = 6, 10%), and macerated tears (n = 25, 42%). There were 6 patients with AHLM cysts in macerated tear group and one patient in vertical tear group. 60 patients were performed arthroscopic meniscus repairs and were followed-up with averaged 18.7 months. Each group had significant postoperative improvement in Lysholm and IKDC scores (p 0.05). This study demonstrated that the macerated tear is common in the tear pattern of AHLM. However, feasibility of the treatment of this type of meniscal tear, especially the meniscus repairs still requires further study.

Effect of diquafosol three per cent ophthalmic solution on tear film and corneal aberrations after cataract surgery.

Science.gov (United States)

Lee, Hun; Kim, Sang Myung; Choi, Seonghee; Seo, Kyoung Yul; Kim, Eung Kweon; Kim, Tae-Im

2017-11-01

The aim was to evaluate the effect of diquafosol on tear film parameters and corneal aberrations after cataract surgery. This retrospective, comparative, observational case series included patients who underwent cataract surgery with or without peri-operative use of diquafosol three per cent ophthalmic solution. Patients in group I (31 eyes) were treated with diquafosol three per cent ophthalmic solution six times a day from one week before surgery to three months after surgery. Patients in group II (33 eyes) underwent cataract surgery without being administered diquafosol. Tear film break-up time (BUT), the ocular surface disease index (OSDI), the Oxford Scheme score, Schirmer's test I and corneal aberrations were determined before and at one and three months post-surgery. In group I, the BUT, OSDI and Oxford Scheme score showed significant improvement at one and three months post-surgery (p = 0.002 for BUT at one month and three months, p = 0.023 and p = 0.049 for OSDI at one month and three months and p = 0.001 and p = 0.026 for Oxford Scheme at one month and three months), compared to baseline. In group II, the BUT, OSDI and Oxford Scheme score did not show any significant improvement during the follow-up period. In both groups, Schirmer's test I significantly decreased at three months post-surgery (p = 0.011 for group I and p = 0.034 for group II), compared to baseline. There were significant differences in the BUT and OSDI between the groups at three months post-surgery (p = 0.037 for BUT and p = 0.011 for OSDI). Regarding the corneal aberration, there were no significant differences between the groups at three months post-surgery. Peri-operative application of diquafosol three per cent ophthalmic solution may prevent dry eye-related ocular surface changes accompanied by improvement of ocular symptom. No definite changes in corneal aberrations were noted. © 2017 Optometry Australia.

Effect of ion viscosity on neoclassical tearing mode

International Nuclear Information System (INIS)

Yoshida, Shigeki; Itoh, Sanae-I.; Yagi, Masatoshi; Azumi, Masafumi

2004-01-01

Linear stability analysis of neoclassical tearing mode (NTM) is performed on the basis of four-field reduced magnetohydrodynamic (MHD) model which takes account of fluctuating ion parallel flow and ion neoclassical viscosity. The dependence of the growth rate on the kinetic effects is investigated. It is shown that the linear NTM is stabilized by ion neoclassical viscosity and that the stabilizing effect of ion parallel compressibility is weak in the banana-plateau regime. It is found that not only ion neoclassical viscosity but also both ion and electron diamagnetic effects are important for the stabilization of NTM. (author)

Thermal stability of pulsed laser deposited iridium oxide thin films at low oxygen atmosphere

Science.gov (United States)

Gong, Yansheng; Wang, Chuanbin; Shen, Qiang; Zhang, Lianmeng

2013-11-01

Iridium oxide (IrO2) thin films have been regarded as a leading candidate for bottom electrode and diffusion barrier of ferroelectric capacitors, some process related issues need to be considered before integrating ferroelectric capacitors into memory cells. This paper presents the thermal stability of pulsed laser deposited IrO2 thin films at low oxygen atmosphere. Emphasis was given on the effect of post-deposition annealing temperature at different oxygen pressure (PO2) on the crystal structure, surface morphology, electrical resistivity, carrier concentration and mobility of IrO2 thin films. The results showed that the thermal stability of IrO2 thin films was strongly dependent on the oxygen pressure and annealing temperature. IrO2 thin films can stably exist below 923 K at PO2 = 1 Pa, which had a higher stability than the previous reported results. The surface morphology of IrO2 thin films depended on PO2 and annealing temperature, showing a flat and uniform surface for the annealed films. Electrical properties were found to be sensitive to both the annealing temperature and oxygen pressure. The room-temperature resistivity of IrO2 thin films with a value of 49-58 μΩ cm increased with annealing temperature at PO2 = 1 Pa. The thermal stability of IrO2 thin films as a function of oxygen pressure and annealing temperature was almost consistent with thermodynamic calculation.

Morphology and thermal stability of Ti-doped copper nitride films

International Nuclear Information System (INIS)

Fan Xiaoyan; Wu Zhiguo; Li Huajun; Geng Baisong; Li Chun; Yan Pengxun

2007-01-01

A weakly Ti-doped copper nitride (Cu 3 N) film was prepared by cylindrical magnetron sputtering. The XPS results indicate that Ti atoms do not substitute for the Cu atoms but probably locate at the grain boundaries. The columnar grains size is about half of that of the undoped Cu 3 N film and the surface is smoother. For weakly Ti-doped Cu 3 N films, a dense layer appears on top of the columnar crystals. The RMS of the Cu film formed by annealing of the weakly Ti-doped Cu 3 N film is more than twice larger than that of the film before annealing. Compared with the undoped Cu 3 N film, it possesses fine thermal stability both in vacuum and in atmosphere

Deltoid muscle and tendon tears in patients with chronic rotator cuff tears

International Nuclear Information System (INIS)

Ilaslan, Hakan; Recht, Michael P.; Iannotti, Joseph P.

2007-01-01

To describe the magnetic resonance imaging (MRI) appearances of tears of the deltoid muscle and tendon in patients with rotator cuff tears and without a prior history of shoulder surgery. Deltoid tears diagnosed on MR examinations were prospectively recorded between February 2003 through June 2004. The images of these patients were then retrospectively reviewed to determine the location of the deltoid tear, the presence of rotator cuff tears, tendon retraction, muscle atrophy, degree of humeral head subluxation, bony erosive changes involving the undersurface of the acromion, and the presence of edema or fluid-like signal intensity in the deltoid muscle and overlying subcutaneous tissues. There were 24 (0.3%) patients with deltoid tears; nine men and 15 women. The age range was 54 to 87 (average 73) years. The right side was involved in 20 cases, and the left in four cases. Fifteen patients had full thickness and nine had partial thickness tears of the deltoid. Shoulder pain was the most common presenting symptom. The physical examination revealed a defect in the region of the deltoid in two patients. Nineteen patients had tears in the muscle belly near the musculotendinous junction, and five had avulsion of the tendon from the acromial origin. Full thickness rotator cuff tears were present in all of the patients, and 22 patients had associated muscle atrophy. Subcutaneous edema and fluid-like signal was present in 15 patients. Tears of the deltoid muscle or tendon is an unusual finding, but they can be seen in patients with chronic massive rotator cuff tears. Partial thickness tears tend to involve the undersurface of the deltoid muscle and tendon. Associated findings such as intramuscular cyst or ganglion in the deltoid muscle belly and subcutaneous edema or fluid-like signal overlying the deltoid in a patient with a rotator cuff tear should raise the suspicion of a deltoid tear. (orig.)

Deltoid muscle and tendon tears in patients with chronic rotator cuff tears

Energy Technology Data Exchange (ETDEWEB)

Ilaslan, Hakan; Recht, Michael P. [Cleveland Clinic, Musculoskeletal Radiology/A21, Division of Radiology, Cleveland, OH (United States); Iannotti, Joseph P. [Cleveland Clinic, Department of Orthopedic Surgery, Cleveland, OH (United States)

2007-06-15

To describe the magnetic resonance imaging (MRI) appearances of tears of the deltoid muscle and tendon in patients with rotator cuff tears and without a prior history of shoulder surgery. Deltoid tears diagnosed on MR examinations were prospectively recorded between February 2003 through June 2004. The images of these patients were then retrospectively reviewed to determine the location of the deltoid tear, the presence of rotator cuff tears, tendon retraction, muscle atrophy, degree of humeral head subluxation, bony erosive changes involving the undersurface of the acromion, and the presence of edema or fluid-like signal intensity in the deltoid muscle and overlying subcutaneous tissues. There were 24 (0.3%) patients with deltoid tears; nine men and 15 women. The age range was 54 to 87 (average 73) years. The right side was involved in 20 cases, and the left in four cases. Fifteen patients had full thickness and nine had partial thickness tears of the deltoid. Shoulder pain was the most common presenting symptom. The physical examination revealed a defect in the region of the deltoid in two patients. Nineteen patients had tears in the muscle belly near the musculotendinous junction, and five had avulsion of the tendon from the acromial origin. Full thickness rotator cuff tears were present in all of the patients, and 22 patients had associated muscle atrophy. Subcutaneous edema and fluid-like signal was present in 15 patients. Tears of the deltoid muscle or tendon is an unusual finding, but they can be seen in patients with chronic massive rotator cuff tears. Partial thickness tears tend to involve the undersurface of the deltoid muscle and tendon. Associated findings such as intramuscular cyst or ganglion in the deltoid muscle belly and subcutaneous edema or fluid-like signal overlying the deltoid in a patient with a rotator cuff tear should raise the suspicion of a deltoid tear. (orig.)

Lessons from the biophysics of interfaces: Lung surfactant and tear fluid

DEFF Research Database (Denmark)

Rantamaki, A.; Telenius, J.; Koivuniemi, A.

2011-01-01

The purpose of this review is to provide insight into the biophysical properties and functions of tear fluid and lung surfactant - two similar fluids covering the epithelium of two distinctive organs. Both fluids form a layer-like structure that essentially comprise of an aqueous layer next......-active function of the fluid film. The lipid layer of lung surfactant comprises mainly of phospholipids, especially phosphatidylcholines, and only small amounts of non-polar lipids, mainly cholesterol. In contrast, tear fluid lipid layer comprises of a mixture of polar and non-polar lipids. However, the relative...... proportion and the spectrum of different polar and non-polar lipids seem to be more extensive in tear fluid than in lung surfactant. The differing lipid compositions generate distinctive lipid layer structures. Despite the structural differences, these lipid layers decrease the surface tension of the air...

Stability and instability of axisymmetric droplets in thermocapillary-driven thin films

Science.gov (United States)

Nicolaou, Zachary G.

2018-03-01

The stability of compactly supported, axisymmetric droplet states is considered for driven thin viscous films evolving on two-dimensional surfaces. Stability is assessed using Lyapunov energy methods afforded by the Cahn-Hilliard variational form of the governing equation. For general driving forces, a criterion on the gradient of profiles at the boundary of their support (their contact slope) is shown to be a necessary condition for stability. Additional necessary and sufficient conditions for stability are established for a specific driving force corresponding to a thermocapillary-driven film. It is found that only droplets of sufficiently short height that satisfy the contact slope criterion are stable. This destabilization of droplets with increasing height is characterized as a saddle-node bifurcation between a branch of tall, unstable droplets and a branch of short, stable droplets.

Exchange of tears under a contact lens is driven by distortions of the contact lens.

Science.gov (United States)

Maki, Kara L; Ross, David S

2014-12-01

We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Influence of toroidal rotation on resistive tearing modes in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Wang, S.; Ma, Z. W., E-mail: zwma@zju.edu.cn [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

2015-12-15

Influence of toroidal equilibrium plasma rotation on m/n = 2/1 resistive tearing modes is studied numerically using a 3D toroidal MHD code (CLT). It is found that the toroidal rotation with or without shear can suppress the tearing instability and the Coriolis effect in the toroidal geometry plays a dominant role on the rotation induced stabilization. For a high viscosity plasma (τ{sub R}/τ{sub V} ≫ 1, where τ{sub R} and τ{sub V} represent resistive and viscous diffusion time, respectively), the effect of the rotation shear combined with the viscosity appears to be stabilizing. For a low viscosity plasmas (τ{sub R}/τ{sub V} ≪ 1), the rotation shear shows a destabilizing effect when the rotation is large.

Collagen films with stabilized liquid crystalline phases and concerns on osteoblast behaviors

Energy Technology Data Exchange (ETDEWEB)

Tang, Minjian; Ding, Shan; Min, Xiang; Jiao, Yanpeng, E-mail: tjiaoyp@jnu.edu.cn; Li, Lihua; Li, Hong; Zhou, Changren, E-mail: tcrz9@jnu.edu.cn

2016-01-01

To duplicate collagen's in vivo liquid crystalline (LC) phase and investigate the relationship between the morphology of LC collagen and osteoblast behavior, a self-assembly method was introduced for preparing collagen films with a stabilized LC phase. The LC texture and topological structure of the films before and after stabilization were observed with polarizing optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The relationship between the collagen films and osteoblast behavior was studied with the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide method, proliferation index detection, alkaline phosphatase measurements, osteocalcin assay, inverted microscopy, SEM observation, AFM observation, and cytoskeleton fluorescence staining. The results showed that the LC collagen film had continuously twisting orientations in the cholesteric phase with a typical series of arced patterns. The collagen fibers assembled in a well-organized orientation in the LC film. Compared to the non-LC film, the LC collagen film can promote cell proliferation, and increase ALP and osteocalcin expression, revealing a contact guide effect on osteoblasts. - Highlights: • Collagen film with liquid crystalline (LC) phase was observed by POM, SEM and AFM. • The effect of LC collagen film on osteoblasts behaviors was studied in detail. • LC collagen film promoted osteoblast proliferation and osteogenesis activity.

Properties of zirconium ceramics and film stabilized by yttrium

International Nuclear Information System (INIS)

Korobova, N.

2004-01-01

Full text: Unstable zirconium dioxide phase transformation can be eliminated by stabilization of the cubic phase with an addition of a selected alkaline earth or rare-earth oxide. Stabilized ZrO 2 has been widely utilized in various high-temperature refractory applications. These stabilized ZrO 2 -base solid solutions also possess rather unique electrical properties, and as a result have considerable potential as solid electrolytes in galvanic and fuel cells and, possibly, as heating elements in high-temperature furnaces. The complex study of synthesis processes, structure and properties of metal alkoxide organic sols have been developed. These have allowed to create main principles of their formation and to show the practical realization of obtained theoretical and experimental results. The correlation between hydrolysis conditions of (Zr+Y) metal alkoxide sols and synthesis of stable colloid multi-component systems has been established. Systematic research of zirconium and yttrium bi-alkoxide electrophoretic deposition was conducted for the first time. The formation mechanism of electrophoretic deposits has been offered and general scientific principles of the electrophoretic process have been formulated. The model of gel deposits structure was proposed. It has enabled to analyze the main (for example, cluster) effects, which have been exhibited in technological procedure for thin film preparation. The structure investigation of stabilized zirconium dioxide thin films and ceramics has been studied. The researches were based on the comparative analysis of the initial gel microstructure and dried gel by the various drying methods. The new approach for drying of gel electrophoretic deposits was formulated theoretically and experimentally has been proved. The modeling of the aggregate kinetics as a type of 'cluster-cluster' has been proposed like a qualitative description of the process. The data of fractal dimensions of aggregates which have been formed at the

Stability of J-aggregated species in an indocarbocyanine dye in Langmuir–Blodgett Films

Energy Technology Data Exchange (ETDEWEB)

Debnath, Pintu [Thin film and Nanoscience Laboratory, Department of Physics, Tripura University, Suryamaninagar 799022, Tripura (India); Chakraborty, Santanu [Department of Physics, NIT Agartala, Jiraniya 799046, Tripura (India); Deb, Subrata [Department of Physics, Women' s College, Agartala 799001, Tripura (India); Nath, Jayasree [Department of Chemistry, Tripura University, Suryamaninagar 799022, Tripura (India); Dey, Bapi; Bhattacharjee, D. [Thin film and Nanoscience Laboratory, Department of Physics, Tripura University, Suryamaninagar 799022, Tripura (India); Hussain, Syed Arshad, E-mail: sa_h153@hotmail.com [Thin film and Nanoscience Laboratory, Department of Physics, Tripura University, Suryamaninagar 799022, Tripura (India)

2016-11-15

Here, the stability behaviour of J-aggregate of an indocarbocyanine dye 1,1′-Dioctadecyl-3,3,3′,3′-Tetramethylindocarbocynine perchlorate (DiI) in fatty acid mixed (X{sub DiI}=0.4) Langmuir–Blodgett (LB) films under different condition was reported. Surface pressure–area per molecule (π–A) isotherm measurement suggest that the molecular interaction between the constituent molecules changes with subphase temperature. UV–vis absorption and fluorescence spectroscopy and Atomic Force Microscopy (AFM) were used to study the stability behaviour. It has been observed that prominent J-aggregate of DiI occurred in the mixed films at subphase temperature 15 °C. With the passage of time as well as post heat treatment DiI J-aggregate decayed to excimer in both mono- and multilayer LB films. Total transition from J-aggregate to excimer occurred in monolayer films, whereas, the transition was partial in multilayer films. The stability of DiI J-aggregate in monolayer films was increased by two ways – (i) depositing the DiI-SA mixed LB films at higher surface pressure, (ii) exposing the films at 50 °C for 5 min. It has been observed that after heat treatment the DiI J-aggregate remained almost stable even after 200 days. AFM investigations gave the compelling visual evidences of the same.

Novel carboxymethyl cellulose-polyvinyl alcohol blend films stabilized by Pickering emulsion incorporation method.

Science.gov (United States)

Fasihi, Hadi; Fazilati, Mohammad; Hashemi, Mahdi; Noshirvani, Nooshin

2017-07-01

The aim of this study was to investigate the possibility of increasing the antimicrobial and antioxidant properties of biodegradable active films stabilized via Pickering emulsions. The blend films were prepared from carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA), emulsified with oleic acid (OL) and incorporated with rosemary essential oil (REO). Formation of Pickering emulsion was confirmed by scanning electron microscopy (SEM), optical microscopy, mean droplet size and emulsion stability. Morphological, optical, physical, mechanical, thermal, antifungal and antioxidant properties of the films incorporated with different concentrations of REO (0.5, 1.5 and 3%) were determined. The results showed an increase in UV absorbance and elongation at break but, a decrease in tensile strength and thermal stability of the films. Interestingly, films containing REO exhibited considerable antioxidant and antimicrobial properties. In vitro microbial tests exhibited 100% fungal inhibition against Penicillium digitatum in the films containing 3% REO. In addition, no fungal growth were observed after 60days of storage at 25°C in bread slices were stored with active films incorporated with 3% REO, could attributed to the slow and regular release of REO caused by Pickering emulsions. The results of this study suggest that Pickering emulsion is a very promising method, which significantly affects antioxidant and antimicrobial activities of the films. Copyright © 2017 Elsevier Ltd. All rights reserved.

Novel polypyrrole films with excellent crystallinity and good thermal stability

International Nuclear Information System (INIS)

Jeeju, Pullarkat P.; Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M.; Jayalekshmi, Sankaran

2012-01-01

Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: ► Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. ► The solution casted films exhibit semi-crystallinity and good thermal stability. ► Percentage crystallinity estimated using XRD and DSC analysis is about 65%. ► Raman studies support the enhancement in crystallinity based on XRD and DSC data. ► The conductivity of the film is 30 times higher than that of HCl doped sample.

Novel polypyrrole films with excellent crystallinity and good thermal stability

Energy Technology Data Exchange (ETDEWEB)

Jeeju, Pullarkat P., E-mail: jeejupp@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M. [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Jayalekshmi, Sankaran, E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India)

2012-06-15

Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: Black-Right-Pointing-Pointer Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. Black-Right-Pointing-Pointer The solution casted films exhibit semi-crystallinity and good thermal stability. Black-Right-Pointing-Pointer Percentage crystallinity estimated using XRD and DSC analysis is about 65%. Black-Right-Pointing-Pointer Raman studies support the enhancement in crystallinity based on XRD and DSC data. Black-Right-Pointing-Pointer The conductivity of the film is 30 times higher than that of HCl doped sample.

Evaluation of point-of-care test for elevated tear matrix metalloproteinase 9 in post-LASIK dry eyes.

Science.gov (United States)

Chan, Tommy C Y; Ye, Cong; Chan, Kwok Ping; Chu, Kai On; Jhanji, Vishal

2016-09-01

To evaluate the performance of a point-of-care test for detection of matrix metalloproteinase 9 (MMP-9) levels in post-laser-assisted in situ keratomileusis (LASIK) dry eyes. A comparative study between patients with mild to moderate post-LASIK dry eyes and age-matched normal subjects was conducted. Ocular surface disease index (OSDI), tear break-up time (TBUT), and tear film MMP-9 and total protein levels were compared between the two groups. A point-of-care test device (RPS InflammaDry, Sarasota, Florida, USA) was utilised to confirm elevated MMP-9 levels in tear film. Fourteen post-LASIK dry eyes and 34 normal eyes were included. There was no significant difference in age and gender between both groups (p>0.175). The OSDI was significantly higher (25.5±7.7 vs 7.4±2.5; pdry eye compared with normal subjects. The tear film MMP-9 levels were 52.7±32.5 ng/mL in dry eyes and 4.1±2.1 ng/mL in normal eyes (p40 ng/mL in 7/14 (50.0%) post-LASIK dry eyes. The InflammaDry was positive in 8/14 (57.1%) post-LASIK eyes. All positive cases had tear film MMP-9 levels ≥38.03 ng/mL. Agreement between InflammaDry and MMP-9 was excellent with Cohen κ value of 0.857 in post-LASIK dry eyes. Only half of post-LASIK dry eyes were found to have significant inflammation associated with elevated MMP-9. The OSDI is useful to non-specifically identify patients with symptomatic dry eye while the InflammaDry determined which patients with dry eye were associated with significant inflammation that may guide therapeutic management decisions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

A comparison of basal and eye-flush tears for the analysis of cat tear proteins.

Science.gov (United States)

Petznick, Andrea; Evans, Margaret D M; Madigan, Michele C; Markoulli, Maria; Garrett, Qian; Sweeney, Deborah F

2011-02-01

To identify a rapid and effective tear collection method providing sufficient tear volume and total protein content (TPC) for analysis of individual proteins in cats. Domestic adult short-haired cats (12-37 months; 2.7-6.6 kg) were used in the study. Basal tears without stimulation and eye-flush tears after instillation of saline (10 μl) were collected using microcapillary tubes from animal eyes either unwounded control or wounded with 9-mm central epithelial debridement giving four groups with n = 3. Tear comparisons were based on total time and rate for tear collection, TPC using micro bicinchoninic acid (BCA), tear immunoglobulin A (IgA), total matrix-metalloproteinase (MMP)-9 concentration using sandwich enzyme-linked immunosorbent assay (ELISA) and MMP-9 activity. Eye-flush tears were collected significantly faster than basal tears in wounded eyes with higher rates for tear collection in unwounded control and wounded eyes. TPC was significantly lower in eye-flush tears compared to basal tears. The relative proportion of tear IgA normalized to TPC (% IgA of TPC) was not significantly different between basal and eye-flush tears. In unwounded control eyes, MMP-9 was slightly higher in eye-flush than in basal tears; activity of MMP-9 in both tear types was similar. In wounded eyes, eye-flush tears showed highest MMP-9 levels and activity on Day 1, which subsequently decreased to Day 7. MMP-9 activity in basal tears from wounded eyes did not display changes in expression. Eye-flush tears can be collected rapidly providing sufficient tear volume and TPC. This study also indicates that eye-flush tears may be more suitable than basal tears for the analysis of MMPs following corneal wounding. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

Potential of FTIR spectroscopy for analysis of tears for diagnosis purposes.

Science.gov (United States)

Travo, Adrian; Paya, Clément; Déléris, Gérard; Colin, Joseph; Mortemousque, Bruno; Forfar, Isabelle

2014-04-01

It has been widely reported that the tear film, which is crucially important as a protective barrier of the eye, undergoes biochemical changes as a result of a wide range of ocular pathology. This tends to suggest the possibility of early detection of ocular diseases on the basis of biochemical analysis of tears. However, studies of tears by conventional methods of biomolecular and biochemical analysis are often limited by methodological difficulties. Moreover, such analysis could not be applied in the clinic, where structural and morphological analyses by, mainly, slit-lamp biomicroscopy remains the recommended method. In this study, we assessed, for the first time, the potential of FTIR spectroscopy combined with advanced chemometric processing of spectral data for analysis of raw tears for diagnosis purposes. We first optimized sampling and spectral acquisition (tears collection method, tear sample volume, and preservation of the samples) for accurate spectral measurement. On the basis of the results, we focused our study on the possibility of discriminating tears from normal individuals from those of patients with different ocular pathologies, and showed that the most discriminating spectral range is that corresponding to variations of CH2 and CH3 of lipid aliphatic chains. We also report more subtle discrimination of tears from patients with keratoconus and those from patients with non-specific inflammatory ocular diseases, on the basis of variations in spectral ranges attributed notably to lipid and carbohydrate vibrations. Finally, we also succeeded in distinguishing tears from patients with early-stage and late-stage keratoconus on the basis of spectral features attributed to protein structure. Therefore, this study strongly suggests that FTIR spectral analysis of tears could be developed as a valuable and cost-saving tool for biochemical-based detection of ocular diseases, potentially before the appearance of the first morphological signs of diseases

High beta and second stability region transport and stability analysis

International Nuclear Information System (INIS)

1991-01-01

This document describes ideal and resistive MHD studies of high-beta plasmas and of the second stability region. Significant progress is reported on the resistive stability properties of high beta poloidal ''supershot'' discharges. For these studies initial profiles were taken from the TRANSP code which is used extensively to analyze experimental data. When an ad hoc method of removing the finite pressure stabilization of tearing modes is implemented it is shown that there is substantial agreement between MHD stability computation and experiment. In particular, the mode structures observed experimentally are consistent with the predictions of the resistive MHD model. We also report on resistive stability near the transition to the second region in TFTR. Tearing modes associated with a nearby infernal mode may explain the increase in MHD activity seen in high beta supershots and which impede the realization of Q∼1. We also report on a collaborative study with PPPL involving sawtooth stabilization with ICRF

Blocked Tear Duct

Science.gov (United States)

... of the nose (lacrimal sac). From there tears travel down a duct (the nasolacrimal duct) draining into your nose. Once in the nose, tears are reabsorbed. A blockage can occur at any point in the tear drainage system, from the puncta ...

Thermal stability of diamond-like carbon–MoS{sub 2} thin films in different environments

Energy Technology Data Exchange (ETDEWEB)

Niakan, H., E-mail: hamid.niakan@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Zhang, C. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Hu, Y. [Canadian Light Source, 101 Perimeter Road, Saskatoon, SK S7N 0X4 (Canada); Szpunar, J.A.; Yang, Q. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada)

2014-07-01

Diamond-like carbon (DLC) based coatings are ideal for low friction and wear resistant applications. For those tribological applications, the coatings may expose to high temperature environments. Therefore, the thermal stability of the coating is very important for its long-term performance. In this work, DLC–MoS{sub 2} composite thin films were synthesized using biased target ion beam deposition technique in which MoS{sub 2} was produced by sputtering a MoS{sub 2} target using Ar ion beams while DLC was deposited by an ion source with CH{sub 4} gas as carbon source. DLC films without MoS{sub 2} deposited under similar conditions were used as reference samples. After the deposition, DLC and DLC–MoS{sub 2} thin films were heat-treated in ambient air and low pressure environments at different temperatures ranging from 100 to 600 °C for 2 h. The effect of annealing on the structure, mechanical and tribological properties of the resulting films were studied by means of Raman spectroscopy, X-ray absorption near edge structure, scanning electron microscopy, nanoindentation, and ball-on-disk testing. The results showed that the structure, hardness, Young's modulus, friction coefficient and wear coefficient of the DLC films were stable up to 200 °C annealing in air and 300 °C in low pressure. At higher temperature, the annealing led to the transformation of sp{sup 3} to sp{sup 2}, which degraded the mechanical and tribological properties of the thin films. Comparing with the DLC films, the DLC–MoS{sub 2} thin films showed a slower rate of graphitization and higher structure stability throughout the range of annealing temperatures, indicating a relatively higher thermal stability. - Highlights: • Thermal stability of diamond-like carbon (DLC) and DLC–MoS{sub 2} films were evaluated. • DLC–MoS{sub 2} films can be synthesized by biased target ion beam deposition technique. • Comparing with DLC films, the DLC–MoS{sub 2} thin films showed higher

The film thickness dependent thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers

Energy Technology Data Exchange (ETDEWEB)

Xiao Xiudi; Xu Gang, E-mail: xiudixiao@163.com; Xiong Bin; Chen Deming; Miao Lei [Chinese Academy of Sciences, Key Laboratory of Renewable Energy and Gas Hydrates, Guangzhou Institute of Energy Conversion (China)

2012-03-15

The monolayer Al{sub 2}O{sub 3}:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 Degree-Sign C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al{sub 2}O{sub 3}:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 Degree-Sign C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers.

Thermal stability of ultrasoft Fe-Zr-N films

NARCIS (Netherlands)

Chechenin, NG; van Veen, A; Schut, H; Chezan, AR; Boerma, D; Vystavel, T; De Hosson, JTM

2003-01-01

The thermal stability of nanocrystalline ultrasoft magnetic (Fe98Zr2)(1-x)N-x films with x = 0.10-0.25 was studied using thermal desorption spectrometry, positron beam analysis and high resolution transmission electron microscopy. The results demonstrate that grain growth during the heat treatment

Optical stability under photo-irradiation of urushi films by ion implantation

Energy Technology Data Exchange (ETDEWEB)

Awazu, Kaoru; Funada, Yoshinori; Kasamori, Masato; Sakamoto, Makoto; Ichikawa, Tachio [Industrial Research Inst. of Ishikawa, Kanazawa (Japan)

1995-06-01

Nitrogen ions, argon ions and others were implanted in urushi-coated surfaces by using a simplified ion implantation apparatus, and the optical stability test was carried out by a sunshine weather meter. The rate of remaining luster on urushi-coated surfaces accompanying ultraviolet irradiation showed respective peculiar behavior according to the kinds of the implanted ions, the time of implantation, transparent and black urushi films, and the use of brightener or not. In electron beam irradiation, change hardly occurred. In urushi-coated products, the luster and the properties are maintained for long period, therefore recently, urushi coating has become to be applied to road sign panels and notice boards in addition to lacquer wares and applied fine art products, and the improvement of the optical stability of urushi films has become the subject. In this study, the experimental methods on urushi coating, ion implantation, the optical stability test and measuring method are explained. The changes of urushi film luster, transmittance, haze, lightness, and chromaticity by nitrogen ion implantation are reported. (K.I.).

Optical stability under photo-irradiation of urushi films by ion implantation

International Nuclear Information System (INIS)

Awazu, Kaoru; Funada, Yoshinori; Kasamori, Masato; Sakamoto, Makoto; Ichikawa, Tachio

1995-01-01

Nitrogen ions, argon ions and others were implanted in urushi-coated surfaces by using a simplified ion implantation apparatus, and the optical stability test was carried out by a sunshine weather meter. The rate of remaining luster on urushi-coated surfaces accompanying ultraviolet irradiation showed respective peculiar behavior according to the kinds of the implanted ions, the time of implantation, transparent and black urushi films, and the use of brightener or not. In electron beam irradiation, change hardly occurred. In urushi-coated products, the luster and the properties are maintained for long period, therefore recently, urushi coating has become to be applied to road sign panels and notice boards in addition to lacquer wares and applied fine art products, and the improvement of the optical stability of urushi films has become the subject. In this study, the experimental methods on urushi coating, ion implantation, the optical stability test and measuring method are explained. The changes of urushi film luster, transmittance, haze, lightness, and chromaticity by nitrogen ion implantation are reported. (K.I.)

Linear analysis of neoclassical tearing mode based on the four-field reduced neoclassical MHD equation

International Nuclear Information System (INIS)

Furuya, Atsushi; Yagi, Masatoshi; Itoh, Sanae-I.

2003-01-01

The linear neoclassical tearing mode is investigated using the four-field reduced neoclassical MHD equations, in which the fluctuating ion parallel flow and ion neoclassical viscosity are taken into account. The dependences of the neoclassical tearing mode on collisionality, diamagnetic drift and q profile are investigated. These results are compared with the results from the conventional three-field model. It is shown that the linear neoclassical tearing mode is stabilized by the ion neoclassical viscosity in the banana regime even if Δ' > 0. (author)

Automated Measurement of Tear Film Dynamics and Lipid Layer Thickness for Assessment of Non-Sjögren Dry Eye Syndrome With Meibomian Gland Dysfunction.

Science.gov (United States)

Ji, Yong Woo; Lee, Jeihoon; Lee, Hun; Seo, Kyoung Yul; Kim, Eung Kweon; Kim, Tae-Im

2017-02-01

To investigate automated values from an advanced corneal topographer with a built-in real keratometer, color camera, and ocular surface interferometer for the evaluation of non-Sjögren dry eye syndrome (NSDES) with meibomian gland dysfunction (MGD). Sixty-four patients (64 eyes) diagnosed with NSDES with MGD were enrolled. All eyes were evaluated using the Ocular Surface Disease Index (OSDI), fluorescence staining score, tear film breakup time (TBUT), Schirmer test, and MGD grade. Noninvasive Keratograph average tear film breakup time (NIKBUTav), tear meniscus height (TMHk), meibomian gland (MG) dropout grade, and lipid layer thickness (LLT) using interferometry were measured. Among automated indexes, NIKBUTav (mean 7.68 ± 4.07 s) and the MG dropout grade (mean 1.0 ± 0.5) significantly correlated with the OSDI (mean 40.6 ± 22.9) (r = -0.337, P = 0.006; and r = 0.201, P = 0.023, respectively), as did all conventional indicators, except the Schirmer score (mean 9.1 ± 5.9 mm). TMHk (mean 0.21 ± 0.18 mm) had significant correlation with the Schirmer score, the staining score (mean 1.2 ± 0.7), TBUT (mean 3.8 ± 1.8 s), and NIKBUTav (r = 0.298, P = 0.007; r = -0.268, P = 0.016; r = 0.459, P < 0.001; and r = 0.439, P < 0.001, respectively), but not any MGD indicator, even the MG dropout grade. NIKBUTav showed significant correlations with all clinical parameters and other automated values, except the Schirmer score and LLT (mean 83.94 ± 20.82 nm) (all (Equation is included in full-text article.)≥ 0.25 and P < 0.01). The MG dropout grade highly correlated with all indexes except TMHk (all (Equation is included in full-text article.)≥ 0.25 and P < 0.05). LLT was significantly associated with TBUT, MGD grade (mean 2.0 ± 0.7), and MG dropout grade (r = 0.219, P = 0.047; r = -0.221, P = 0.039; and r = 0.433, P < 0.001, respectively), although it was not related to patient symptoms. Automated noninvasive measurements using an advanced corneal topographer and LLT

MRI findings in bucket-handle tears of the triangular fibrocartilage complex

International Nuclear Information System (INIS)

Jose, Jean; Arizpe, Azael; Chen, David; Barrera, Carlos M.; Ezuddin, Nisreen Shabbir

2018-01-01

The triangular fibrocartilage complex (TFCC) is an intricate ligamentous and cartilaginous structure that helps transmit axial load across the wrist, and provide stability to the ulnocarpal and distal radioulnar joints (DRUJ). Because the blood supply to the TFCC varies depending on location, certain types of tears are more amenable to surgical repair than others. Since Palmer proposed his classification system of TFCC tears in 1989, only 1 case of a ''bucket-handle'' type tear has been reported. In this article, we describe two new cases of bucket-handle tears of the TFCC. In both cases, the torn fragment was displaced into a previously undescribed location (intra-articular DRUJ and prestyloid recess). Because this type of injury pattern has not been previously well characterized in the literature and such cases rarely reported, MRI findings have not been fully described and its implications on clinical management have largely yet to be determined. (orig.)

MRI findings in bucket-handle tears of the triangular fibrocartilage complex

Energy Technology Data Exchange (ETDEWEB)

Jose, Jean [University of Miami Miller School of Medicine, Department of Radiology, Jackson Memorial Hospital, Miami, FL (United States); University of Miami Miller School of Medicine, Department of Orthopedic Surgery, Uhealth Sports Medicine Institute, Miami, FL (United States); Arizpe, Azael; Chen, David [University of Miami Miller School of Medicine, Department of Orthopedic Surgery, Jackson Memorial Hospital, Miami, FL (United States); Barrera, Carlos M.; Ezuddin, Nisreen Shabbir [University of Miami, Miller School of Medicine, Coral Gables, FL (United States)

2018-03-15

The triangular fibrocartilage complex (TFCC) is an intricate ligamentous and cartilaginous structure that helps transmit axial load across the wrist, and provide stability to the ulnocarpal and distal radioulnar joints (DRUJ). Because the blood supply to the TFCC varies depending on location, certain types of tears are more amenable to surgical repair than others. Since Palmer proposed his classification system of TFCC tears in 1989, only 1 case of a ''bucket-handle'' type tear has been reported. In this article, we describe two new cases of bucket-handle tears of the TFCC. In both cases, the torn fragment was displaced into a previously undescribed location (intra-articular DRUJ and prestyloid recess). Because this type of injury pattern has not been previously well characterized in the literature and such cases rarely reported, MRI findings have not been fully described and its implications on clinical management have largely yet to be determined. (orig.)

Assessment of tear osmolarity and other dry eye parameters in post-LASIK eyes.

Science.gov (United States)

Hassan, Ziad; Szalai, Eszter; Berta, Andras; Modis, Laszlo; Nemeth, Gabor

2013-07-01

To assess the tear osmolarity using the TearLab device after laser in situ keratomileusis (LASIK) and to compare the values with those obtained by traditional tear film tests before and after the procedure. Thirty eyes of 15 refractive surgery candidates (5 men and 10 women of mean age: 30.55 ± 11.79 years) were examined. Using a special questionnaire (Ocular Surface Disease Index), subjective dry eye complaints were evaluated, and then, the tear osmolarity was measured with the TearLab system (TearLab Corporation) and conventional dry eye tests were carried out. Examinations were performed preoperatively and at 1, 30, and 60 days after the surgery. The mean value of tear osmolarity was 303.62 ± 12.29 mOsm/L before the surgery and 303.58 ± 20.14 mOsm/L at 60 days after the treatment (P = 0.69). Mean lid parallel conjunctival folds value was 0.68 ± 0.68 before the procedure and 0.58 ± 0.65 subsequent to surgery (P = 0.25). Meibomian gland dysfunction was not detected. No significant deviation was observed in the values of Schirmer test, corneal staining, tear break-up time, and lid parallel conjunctival folds when compared with postoperatively obtained values during the follow-up period (P > 0.05). During LASIK flap creation, intact corneal innervation is damaged, and the ocular surface lacrimal functional unit can be impaired. In our study, no abnormal dry eye test results were observed before or after the procedure. Based on our results, LASIK treatment is safe for dry eye involving the administration of adequate artificial tears for a minimum of 3 months.

Evaporation of Particle-Stabilized Emulsion Sunscreen Films.

Science.gov (United States)

Binks, Bernard P; Fletcher, Paul D I; Johnson, Andrew J; Marinopoulos, Ioannis; Crowther, Jonathan M; Thompson, Michael A

2016-08-24

We recently showed (Binks et al., ACS Appl. Mater. Interfaces, 2016, DOI: 10.1021/acsami.6b02696) how evaporation of sunscreen films consisting of solutions of molecular UV filters leads to loss of UV light absorption and derived sun protection factor (SPF). In the present work, we investigate evaporation-induced effects for sunscreen films consisting of particle-stabilized emulsions containing a dissolved UV filter. The emulsions contained either droplets of propylene glycol (PG) in squalane (SQ), droplets of SQ in PG or droplets of decane in PG. In these different emulsion types, the SQ is involatile and shows no evaporation, the PG is volatile and evaporates relatively slowly, whereas the decane is relatively very volatile and evaporates quickly. We have measured the film mass and area, optical micrographs of the film structure, and the UV absorbance spectra during evaporation. For emulsion films containing the involatile SQ, evaporation of the PG causes collapse of the emulsion structure with some loss of specular UV absorbance due to light scattering. However, for these emulsions with droplets much larger than the wavelength of light, the light is scattered only at small forward angles so does not contribute to the diffuse absorbance and the film SPF. The UV filter remains soluble throughout the evaporation and thus the UV absorption by the filter and the SPF remain approximately constant. Both PG-in-SQ and SQ-in-PG films behave similarly and do not show area shrinkage by dewetting. In contrast, the decane-in-PG film shows rapid evaporative loss of the decane, followed by slower loss of the PG resulting in precipitation of the UV filter and film area shrinkage by dewetting which cause the UV absorbance and derived SPF to decrease. Measured UV spectra during evaporation are in reasonable agreement with spectra calculated using models discussed here.

Noninvasive Dry Eye Assessment Using High-Technology Ophthalmic Examination Devices.

Science.gov (United States)

Yamaguchi, Masahiko; Sakane, Yuri; Kamao, Tomoyuki; Zheng, Xiaodong; Goto, Tomoko; Shiraishi, Atsushi; Ohashi, Yuichi

2016-11-01

Recently, the number of dry eye cases has dramatically increased. Thus, it is important that easy screening, exact diagnoses, and suitable treatments be available. We developed 3 original and noninvasive assessments for this disorder. First, a DR-1 dry eye monitor was used to determine the tear meniscus height quantitatively by capturing a tear meniscus digital image that was analyzed by Meniscus Processor software. The DR-1 meniscus height value significantly correlated with the fluorescein meniscus height (r = 0.06, Bland-Altman analysis). At a cutoff value of 0.22 mm, sensitivity of the dry eye diagnosis was 84.1% with 90.9% specificity. Second, the Tear Stability Analysis System was used to quantitatively measure tear film stability using a topographic modeling system corneal shape analysis device. Tear film stability was objectively and quantitatively evaluated every second during sustained eye openings. The Tear Stability Analysis System is currently installed in an RT-7000 autorefractometer and topographer to automate the diagnosis of dry eye. Third, the Ocular Surface Thermographer uses ophthalmic thermography for diagnosis. The decrease in ocular surface temperature in dry eyes was significantly greater than that in normal eyes (P eye opening. Decreased corneal temperature correlated significantly with the tear film breakup time (r = 0.572; P dry eye, sensitivity was 0.83 and specificity was 0.80 after 10 seconds. This article describes the details and potential of these 3 noninvasive dry eye assessment systems.

Using high thermal stability flexible thin film thermoelectric generator at moderate temperature

Science.gov (United States)

Zheng, Zhuang-Hao; Luo, Jing-Ting; Chen, Tian-Bao; Zhang, Xiang-Hua; Liang, Guang-Xing; Fan, Ping

2018-04-01

Flexible thin film thermoelectric devices are extensively used in the microscale industry for powering wearable electronics. In this study, comprehensive optimization was conducted in materials and connection design for fabricating a high thermal stability flexible thin film thermoelectric generator. First, the thin films in the generator, including the electrodes, were prepared by magnetron sputtering deposition. The "NiCu-Cu-NiCu" multilayer electrode structure was applied to ensure the thermal stability of the device used at moderate temperature in an air atmosphere. A design with metal layer bonding and series accordant connection was then employed. The maximum efficiency of a single PN thermocouple generator is >11%, and the output power loss of the generator is <10% after integration.

Equilibrium current-driven tearing mode in the hydrodynamic regime

International Nuclear Information System (INIS)

Cozzani, F.; Mahajan, S.

1984-12-01

The effect of the parallel equilibrium current on the linear stability of the drift-tearing mode in the collisional regime is investigated analytically. In the appropriate parameter regime, a new unstable mode, driven by equilibrium current, is found and its relevance to tokamak discharges is discussed

The thermal stability of the carbon-palladium films for hydrogen sensor applications

Science.gov (United States)

Rymarczyk, Joanna; Czerwosz, ElŻbieta; Diduszko, Ryszard; Kozłowski, Mirosław

2017-08-01

The thermal stability of two types of C-Pd films prepared in PVD process were studied. These films are composed of Pd nanograins embedded in a multiphase carbonaceous matrix. These films were distinguished by Pd content. These films were annealed in a range of temperatures 50÷1000°C. The structural, topographical and molecular changes were studied by scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and X-ray diffraction (XRD) methods. The results show that investigated films are thermally stable up to 200°C.

An innovative interpretation of rotating tearing mode locking to an external static current

International Nuclear Information System (INIS)

Coelho, R.; Lazzaro, E.

2001-01-01

Naturally occurring error fields in tokamaks, which arise from misalignments of the external field coils, may trigger the onset of tearing modes. The conditions under which a static error field is able to lock a rotating tearing mode and how this process takes place are discussed. The analysis presented contributes to a new understanding and interpretation of mode locking, given in terms of the superposition of a slipping layer (a radial layer of very fast mode phase variations) and the tearing layer, where reconnection takes place. In addition, a stabilizing operating window is found to exist, independent of the phase time evolution of the mode. (author). Letter-to-the-editor

The Relationship Between Tear Ferning Patterns and Non-invasive Tear Break-up Time in Normal Asian Population.

Science.gov (United States)

Sharanjeet-Kaur; Ho, Chien Yee; Mutalib, Haliza Abdul; Ghazali, Ahmad Rohi

2016-01-01

To investigate the relationship between tear ferning patterns (TFP) and non-invasive tear break-up time (NIBUT) in normal Asian subjects. One hundred and forty-five adults with no ocular surface disorders were recruited. TFP and NIBUT were determined. Tears were collected using a capillary tube and allowed to air dry at room temperature for 10min. TFP was later observed using a light microscope and classified according to Rolando's classification. Measurement for NIBUT was obtained using a Tearscope with the slit lamp magnification. It was found that there is no significant difference between gender in TFP (Z=-1.77, P>.05) and NIBUT (Z=-1.475, P>.05). There is also no significant difference between Malay, Chinese, Indian, and other races in TFP, (H(3)=4.85, P>.05) and NIBUT (H(3)=2.18, P>.05). However, there is a significant difference between age groups of 20-29, 30-39, 40-49,and 50-60 years old in both TFP (H(3)=28.25, P<.01) and NIBUT (H(3)=36.50, P<.001). Spearman's correlation showed there was a significant relationship between TFP and NIBUT (r=-0.55, P<.001), age and NIBUT (r=-0.50, P<.001), age and TFP (r=0.41, P<.001), McMonnies score and NIBUT (r=-0.40, P<.001), McMonnies score and TFP (r=0.31, P<.001), as well as age and McMonnies score (r=0.52, P<.001). TFP and NIBUT was age dependent but not gender and race dependent. Older subjects had higher grade of TFP and McMonnies questionnaire score but lower NIBUT value. TFP and NIBUT can be used to assess the tear film quality. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Clinical performance of an objective methodology to categorize tear film lipid layer patterns

Science.gov (United States)

Garcia-Resua, Carlos; Pena-Verdeal, Hugo; Giraldez, Maria J.; Yebra-Pimentel, Eva

2017-08-01

Purpose: To validate the performance of a new objective application designated iDEAS (Dry Eye Assessment System) to categorize different zones of lipid layer patterns (LLPs) in one image. Material and methods: Using the Tearscopeplus and a digital camera attached to a slit-lamp, 50 images were captured and analyzed by 4 experienced optometrists. In each image the observers outlined tear film zones that they clearly identified as a specific LLP. Further, the categorization made by the 4 optometrists (called observer 1, 2, 3 and 4) was compared with the automatic system included in iDEAS (5th observer). Results: In general, observer 3 classified worse than all observers (observers 1, 2, 4 and automatic application, Wilcoxon test, 0.05). Furthermore, we obtained a set of photographs per LLP category for which all optometrists showed agreement by using the new tool. After examining them, we detected the more characteristic features for each LLP to enhance the description of the patterns implemented by Guillon. Conclusions: The automatic application included in the iDEAS framework is able to provide zones similar to the annotations made by experienced optometrists. Thus, the manual process done by experts can be automated with the benefits of being unaffected by subjective factors.

Changes in the evaporation rate of tear film after digital expression of meibomian glands in patients with and without dry eye.

Science.gov (United States)

Arciniega, Juan Carlos; Wojtowicz, Jadwiga Cristina; Mohamed, Engy Mostafa; McCulley, James Parker

2011-08-01

To evaluate the effect of excess meibum on tear evaporation rate in patients with and without dry eye. Eleven healthy subjects and 16 patients with dry eye were tested. The dry eye group was divided into 2 subgroups: classic keratoconjunctivitis sicca (KCS) with clear and easily expressed meibum and KCS with meibomian gland dysfunction (MGD) with turbid secretions and difficult-to-express meibum. Evaporative measurements were performed at baseline and after digital expression of meibomian glands at 12, 24, 36, and 48 minutes. Two ranges of relative humidity were used, 25% to 35% and 35% to 45%. The data were expressed as microliters per square centimeter per minute. An increase in the evaporation rate of the tear film was noted for all measurements at both relative humidities in the classic KCS and KCS with MGD groups compared with healthy subjects (P evaporation rates at relative humidities of 25% to 35% and 35% to 45% were 0.056 ± 0.016 and 0.040 ± 0.008 for the classic KCS group; 0.055 ± 0.026 and 0.037 ± 0.019 for the KCS with MGD group and 0.033 ± 0.012 and 0.023 ± 0.008 for the healthy group. Also, a decrease in the evaporation rate was observed in the healthy and KCS with MGD groups between baseline and the first measurement after digital expression for both relative humidities (P evaporation rates compared with the healthy group. Aqueous tear evaporation diminished in the healthy and KCS with MGD groups after expression of meibomian glands. However, this effect was transient and negligible after the second measurement.

Investigation of pepsin in tears of children with laryngopharyngeal reflux disease.

Science.gov (United States)

Iannella, Giannicola; Di Nardo, Giovanni; Plateroti, Rocco; Rossi, Paolo; Plateroti, Andrea Maria; Mariani, Paola; Magliulo, Giuseppe

2015-12-01

Numerous investigations postulated that laryngopharyngeal reflux (LPR) is implicated in the pathogenesis of various upper airway inflammatory diseases as sinusitis or dacryostenosis. The presence of pepsin in tears might be confirmed the presuntive hypothesis of the arrival in the nasolacrimal ducts and precorneal tears film through the laryngopharyngeal reflux of either gastric acid or stomach secretions (pepsin) with inflammatory potentialities. The aim of this preliminary study was to identify the presence or absence of pepsin in the tears collected from children with a high suspicion of LPR who underwent 24-h pH (MII-pH) monitoring to confirm the disease. This study enrolled 20 patients suffering from symptoms of laryngopharyngeal reflux that underwent 24-h multichannel intraluminal impedance (MII)-pH monitoring to confirm the disease. The findings of the study group were compared with those of a control group of patients with negative pH monitoring. The quantitative analysis of human pepsin concentration in the tear samples was performed by ELISA method in both groups. Four children (20%) of the study group showed pepsin in the tears. All of the subjects belonging to the control group were negative for its presence. No difference differences in the total number of reflux episodes and the number of weakly basic reflux in the pepsin positive patients vs. pepsin negative children were present. 20% of the children with diagnosed LPR showed pepsin in the tears. Our specific investigation might provide information regarding sinusitis or dacryostenosis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Tearing instabilities in turbulence

International Nuclear Information System (INIS)

Ishizawa, A.; Nakajima, N.

2009-01-01

Full text: Effects of micro-turbulence on tearing instabilities are investigated by numerically solving a reduced set of two-fluid equations. Micro-turbulence excites both large-scale and small-scale Fourier modes through energy transfer due to nonlinear mode coupling. The energy transfer to large scale mode does not directly excite tearing instability but it gives an initiation of tearing instability. When tearing instability starts to grow, the excited small scale mode plays an important role. The mixing of magnetic flux by micro-turbulence is the dominant factor of non-ideal MHD effect at the resonant surface and it gives rise to magnetic reconnection which causes tearing instability. Tearing instabilities were investigated against static equilibrium or flowing equilibrium so far. On the other hand, the recent progress of computer power allows us to investigate interactions between turbulence and coherent modes such as tearing instabilities in magnetically confined plasmas by means of direct numerical simulations. In order to investigate effects of turbulence on tearing instabilities we consider a situation that tearing mode is destabilized in a quasi-equilibrium including micro-turbulence. We choose an initial equilibrium that is unstable against kinetic ballooning modes and tearing instabilities. Tearing instabilities are current driven modes and thus they are unstable for large scale Fourier modes. On the other hand kinetic ballooning modes are unstable for poloidal Fourier modes that are characterized by ion Larmor radius. The energy of kinetic ballooning modes spreads over wave number space through nonlinear Fourier mode coupling. We present that micro-turbulence affects tearing instabilities in two different ways by three-dimensional numerical simulation of a reduced set of two-fluid equations. One is caused by energy transfer to large scale modes, the other is caused by energy transfer to small scale modes. The former is the excitation of initial

Hydrodynamic stability of thermoviscous liquid film inside a rotating horizontal cylinder: Heating and cooling effects

Science.gov (United States)

Kumawat, Tara Chand; Tiwari, Naveen

2018-03-01

Steady two-dimensional solutions and their stability analysis are presented for thin film of a thermoviscous liquid flowing inside a cylinder rotating about its horizontal axis. The inner surface of the cylinder is either uniformly hotter or colder than the enveloping air. The mass, momentum, and energy equations are simplified using thin-film approximation. The analytically obtained film thickness evolution equation consists of various dimensionless parameters such as gravitational number, Bond number, Biot number, thermoviscosity number, and Marangoni number. The viscosity of the liquid is considered as an exponential function of temperature. The viscosity increases (decreases) within the film thickness away from the inner surface of the cylinder when the surface is uniformly hotter (colder) than the atmosphere. For hotter (colder) surface, the film thickness on the rising side decreases (increases) when convective heat transfer at the free surface is increased. The surface tension gradient at the free surface generates Marangoni stress that has a destabilizing (stabilizing) effect on the thin film flow in the case of a hotter (colder) cylinder. The thermoviscosity number stabilizes (destabilizes) the flow on a heating (cooling) surface and this effect increases with an increase in the heat transfer at the free surface. For a hotter surface and in the presence of Marangoni stress, the convective heat transfer at the interface has the destabilizing effect for small values of the Biot number and assumes a stabilizing role for larger values. Non-linear simulations show consistency with the linear stability analysis.

Finite element analysis for the initiation of lamellar tearing in welded joints

International Nuclear Information System (INIS)

Krieg, R.D.; Thomas, R.K.

1980-01-01

A numerical procedure using the finite element method is presented for predicting the initiation of lamellar tearing in fillet welded T-joints commonly employed in large structures. Starting with a prescribed geometry, the welding process is approximated by a known time-dependent volumetric heat source which simulates the arc heating and deposition of liquid metal. The transient nonlinear thermal and stress problems are then solved using finite element computer codes. Results of the elastic-plastic stress analysis are presented showing a predicted region of incipient lamellar tearing based on a ductile fracture theory which qualitatively agrees with the size and location of tears typically observed in photomicrographs. Additional insight into post failure crack length and stability is presented based on a simplified linear elastic fracture mechanics approach. Although the analysis procedure shows signs of promise, several weak points in the model are pointed out which must be improved before lamellar tearing can be quantified in an approach of this general type

On the merits of heating and current drive for tearing mode stabilization

NARCIS (Netherlands)

De Lazzari, D.; Westerhof, E.

2009-01-01

Neoclassical tearing modes (NTMs) are magnetohydrodynamic modes that can limit the performance of high beta discharges in a tokamak, leading eventually to a plasma disruption. A NTM is sustained by the perturbation of the 'bootstrap' current, which is a consequence of the pressure

Thermal stability of tungsten sub-nitride thin film prepared by reactive magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Zhang, X.X. [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730050 (China); Wu, Y.Z., E-mail: youzhiwu@163.com [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050 (China); Mu, B. [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou, 730050 (China); Qiao, L. [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730050 (China); Li, W.X.; Li, J.J. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, P., E-mail: pengwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730050 (China)

2017-03-15

Tungsten sub-nitride thin films deposited on silicon samples by reactive magnetron sputtering were used as a model system to study the phase stability and microstructural evolution during thermal treatments. XRD, SEM&FIB, XPS, RBS and TDS were applied to investigate the stability of tungsten nitride films after heating up to 1473 K in vacuum. At the given experimental parameters a 920 nm thick crystalline film with a tungsten and nitrogen stoichiometry of 2:1 were achieved. The results showed that no phase and microstructure change occurred due to W{sub 2}N film annealing in vacuum up to 973 K. Heating up to 1073 K led to a partial decomposition of the W{sub 2}N phase and the formation of a W enrichment layer at the surface. Increasing the annealing time at the same temperature, the further decomposition of the W{sub 2}N phase was negligible. The complete decomposition of W{sub 2}N film happened as the temperature reached up to 1473 K.

Meniscus Tears (For Teens)

Science.gov (United States)

... Safe Videos for Educators Search English Español Meniscus Tears KidsHealth / For Teens / Meniscus Tears What's in this ... surgery to fix it. What Is a Meniscus Tear? Your knee is made up of three bones: ...

Geometrical influences on neoclassical magnetohydrodynamic tearing modes

International Nuclear Information System (INIS)

Kruger, S.E.; Hegna, C.C.; Callen, J.D.

1997-07-01

The influence of geometry on the pressure drives of nonideal magnetohydrodynamic tearing modes is presented. In order to study the effects of elongation, triangularity, and aspect ratio, three different machines are considered to provide a range of tokamak configurations: TFTR (circular), DIII-D (D-shaped), and Pegasus (extremely low aspect ratio). For large aspect ratio tokamaks, shaping does very little to influence the pressure gradient drives, while at low aspect ratios, a very strong sensitivity to the profiles is found. In particular, this sensitivity is connected to the strong dependence on the magnetic shear. This suggests that at low aspect ratio it may be possible to stabilize neoclassical tearing modes by flattening the q profile near low order rational surfaces (e.g., q = 2/1) using a combination of shaping and localized current drive, whereas at large aspect ratio it is more difficult

[Rotator cuff tear athropathy prevalence].

Science.gov (United States)

Guerra-Soriano, F; Encalada-Díaz, M I; Ruiz-Suárez, M; Valero-González, F S

2017-01-01

Glenohumeral arthritis secondary to massive rotator cuff tear presents with a superior displacement and femoralization of the humeral head with coracoacromial arch acetabularization. The purpose of this study was to establish prevalence of rotator cuff tear artropathy (CTA) at our institution. Four hundred electronic records were reviewed from which we identified 136 patients with rotator cuff tears. A second group was composed with patients with massive cuff tears that were analized and staged by the Seebauer cuff tear arthropathy classification. Thirty four patients with massive rotator cuff tears were identified, 8 male and 26 female (age 60.1 ± 10.26 years). Massive rotator cuff tear prevalence was 25%. CTA prevalence found in the rotator cuff group was 19 and 76% in the massive cuff tears group. Patients were staged according to the classification with 32% in stage 1a, 11% 1b, 32% 2a and 0% 2b. CTA prevalence in patients with rotator cuff tears and massive cuff tears is higher than the one reported in American population. We consider that a revision of the Seebauer classification to be appropriate to determine its reliability.

Changes in Tear Volume after 3% Diquafosol Treatment in Patients with Dry Eye Syndrome: An Anterior Segment Spectral-domain Optical Coherence Tomography Study.

Science.gov (United States)

Lee, Kwan Bok; Koh, Kyung Min; Kwon, Young A; Song, Sang Wroul; Kim, Byoung Yeop; Chung, Jae Lim

2017-08-01

To evaluate changes in the tear meniscus area and tear meniscus height over time in patients with dry eye syndrome, using anterior segment spectral-domain optical coherence tomography after the instillation of 3% diquafosol ophthalmic solution. Sixty eyes from 30 patients with mild to moderate dry eye syndrome were included. Tear meniscus images acquired by anterior segment spectral-domain optical coherence tomography were analyzed using National Institutes of Health's image-analysis software (ImageJ 1.44p). Tear meniscus area and tear meniscus height were measured at baseline, 5 minutes, 10 minutes, and 30 minutes after instillation of a drop of diquafosol in one eye and normal saline in the other eye. Changes in ocular surface disease index score, tear film break-up time, corneal staining score by Oxford schema, and meibomian expressibility were also evaluated at baseline, and after 1 week and 1 month of a diquafosol daily regimen. Sixty eyes from 30 subjects (mean age, 29.3 years; 8 men and 22 women) were included. In eyes receiving diquafosol, tear volume was increased at 5 and 10 minutes compared with baseline. It was also higher than saline instilled eyes at 5, 10, and 30 minutes. Changes in tear volume with respect to baseline were not statistically different after the use of diquafosol for 1 month. Ocular surface disease index score, tear film break-up time, and Oxford cornea stain score were significantly improved after 1 week and 1 month of daily diquafosol instillation, but meibomian expressibility did not change. Topical diquafosol ophthalmic solution effectively increased tear volume for up to 30 minutes, compared to normal saline in patients with dry eye syndrome. © 2017 The Korean Ophthalmological Society

The influence of simulated rotator cuff tears on the risk for impingement in handbike and handrim wheelchair propulsion

NARCIS (Netherlands)

van Drongelen, S.; Schlussel, M.; Arnet, U.; Veeger, H.E.J.

2013-01-01

Background: Rotator cuff tears strongly affect the biomechanics of the shoulder joint in their role to regulate the joint contact force needed to prevent the joint from dislocation. The aim of this study was to investigate the influence of simulated progressed rotator cuff tears on the (in)stability

Synthesis, microstructural, optical and mechanical properties of yttria stabilized zirconia thin films

International Nuclear Information System (INIS)

Amézaga-Madrid, P.; Hurtado-Macías, A.; Antúnez-Flores, W.; Estrada-Ortiz, F.; Pizá-Ruiz, P.; Miki-Yoshida, M.

2012-01-01

Highlights: ► Thin films of YSZ obtained by AACVD have high quality. ► They are uniform, very transparent, and have high hardness. ► Optical characterization were performed in detail, optical constants and band gap energy were determined as a function of dopant content. - Abstract: Thin films of yttria-stabilized zirconia (YSZ) exhibit exceptional properties, such as high thermal, chemical and mechanical stability. Here, we report the synthesis of YSZ thin films by aerosol assisted chemical vapour deposition onto borosilicate glass and fused silica substrates. Optimum deposition temperature was 673 ± 5 K. In addition, different Y content was tried to analyse its influence in the microstructure and properties of the films. The films were uniform, transparent and non-light scattering. Surface morphology and cross sectional microstructure were studied by field emission scanning electron microscopy. The microstructure of the films was characterized by grazing incidence X-ray diffraction. Crystallite size and lattice parameter were obtained. Optical properties were analysed from reflectance and transmittance spectra; from these measurements, optical constants and band gap were obtained. Quantum confinement effect, due to the small grain size of the films, was evident in the high band gap energy obtained. Nanoindentation tests were realized at room temperature employing the continuous stiffness measurement method, to determine the hardness and elastic modulus as a function of Y content.

Preparation and characterization of epitaxially grown unsupported yttria-stabilized zirconia (YSZ) thin films

Energy Technology Data Exchange (ETDEWEB)

Götsch, Thomas; Mayr, Lukas [Institute of Physical Chemistry, Universität Innsbruck, A-6020 Innsbruck (Austria); Stöger-Pollach, Michael [University Service Center for Transmission Electron Microscopy (USTEM), Vienna University of Technology, A-1040 Vienna (Austria); Klötzer, Bernhard [Institute of Physical Chemistry, Universität Innsbruck, A-6020 Innsbruck (Austria); Penner, Simon, E-mail: simon.penner@uibk.ac.at [Institute of Physical Chemistry, Universität Innsbruck, A-6020 Innsbruck (Austria)

2015-03-15

Highlights: • Preparation of unsupported yttrium-stabilized zirconia films. • Control of ordering and epitaxy by temperature of deposition template. • Adjustment of film defectivity by deposition and post-oxidation temperature. • Reproducibility of target stoichiometry in the deposited films. • Lateral and vertical chemical homogeneity. - Abstract: Epitaxially grown, chemically homogeneous yttria-stabilized zirconia thin films (“YSZ”, 8 mol% Y{sub 2}O{sub 3}) are prepared by direct-current sputtering onto a single-crystalline NaCl(0 0 1) template at substrate temperatures ≥493 K, resulting in unsupported YSZ films after floating off NaCl in water. A combined methodological approach by dedicated (surface science) analytical characterization tools (transmission electron microscopy and diffraction, atomic force microscopy, angle-resolved X-ray photoelectron spectroscopy) reveals that the film grows mainly in a [0 0 1] zone axis and no Y-enrichment in surface or bulk regions takes place. In fact, the Y-content of the sputter target is preserved in the thin films. Analysis of the plasmon region in EEL spectra indicates a defective nature of the as-deposited films, which can be suppressed by post-deposition oxidation at 1073 K. This, however, induces considerable sintering, as deduced from surface morphology measurements by AFM. In due course, the so-prepared unsupported YSZ films might act as well-defined model systems also for technological applications.

Perovskite Oxide Thin Film Growth, Characterization, and Stability

Science.gov (United States)

Izumi, Andrew

Studies into a class of materials known as complex oxides have evoked a great deal of interest due to their unique magnetic, ferroelectric, and superconducting properties. In particular, materials with the ABO3 perovskite structure have highly tunable properties because of the high stability of the structure, which allows for large scale doping and strain. This also allows for a large selection of A and B cations and valences, which can further modify the material's electronic structure. Additionally, deposition of these materials as thin films and superlattices through techniques such as pulsed laser deposition (PLD) results in novel properties due to the reduced dimensionality of the material. The novel properties of perovskite oxide heterostructures can be traced to a several sources, including chemical intermixing, strain and defect formation, and electronic reconstruction. The correlations between microstructure and physical properties must be investigated by examining the physical and electronic structure of perovskites in order to understand this class of materials. Some perovskites can undergo phase changes due to temperature, electrical fields, and magnetic fields. In this work we investigated Nd0.5Sr 0.5MnO3 (NSMO), which undergoes a first order magnetic and electronic transition at T=158K in bulk form. Above this temperature NSMO is a ferromagnetic metal, but transitions into an antiferromagnetic insulator as the temperature is decreased. This rapid transition has interesting potential in memory devices. However, when NSMO is deposited on (001)-oriented SrTiO 3 (STO) or (001)-oriented (LaAlO3)0.3-(Sr 2AlTaO6)0.7 (LSAT) substrates, this transition is lost. It has been reported in the literature that depositing NSMO on (110)-oriented STO allows for the transition to reemerge due to the partial epitaxial growth, where the NSMO film is strained along the [001] surface axis and partially relaxed along the [11¯0] surface axis. This allows the NSMO film enough

Human tears contain a chemosignal.

Science.gov (United States)

Gelstein, Shani; Yeshurun, Yaara; Rozenkrantz, Liron; Shushan, Sagit; Frumin, Idan; Roth, Yehudah; Sobel, Noam

2011-01-14

Emotional tearing is a poorly understood behavior that is considered uniquely human. In mice, tears serve as a chemosignal. We therefore hypothesized that human tears may similarly serve a chemosignaling function. We found that merely sniffing negative-emotion-related odorless tears obtained from women donors induced reductions in sexual appeal attributed by men to pictures of women's faces. Moreover, after sniffing such tears, men experienced reduced self-rated sexual arousal, reduced physiological measures of arousal, and reduced levels of testosterone. Finally, functional magnetic resonance imaging revealed that sniffing women's tears selectively reduced activity in brain substrates of sexual arousal in men.

Effects of oxidation potential and retention time on electrochromic stability of poly (3-hexyl thiophene) films

Science.gov (United States)

Kim, Tae-Ho; Hyun Song, Seok; Kim, Hyo-Jae; Oh, Seong-Hyeon; Han, Song-Yi; Kim, Goung; Nah, Yoon-Chae

2018-06-01

Herein, we report the effects of applied voltage on the electrochromic (EC) stability of poly(3-hexylthiophene) (P3HT) films during EC reactions. The transmittance difference and cycling stability of these films were monitored to optimize the oxidation voltage, and their chemical compositions were analyzed by X-ray photoelectron spectroscopy after long-term electrochemical cycling. High oxidation voltages increased the color contrast of P3HT films but decreased their cycling stability due to facilitating chemical degradation. Furthermore, at an optimized oxidation voltage, the retention time during potential pulsing was adjusted utilizing the optical memory of P3HT, revealing that the decreased voltage application time reduced power consumption by 9.6% and enhanced EC stability without loss of color contrast.

Foam-film-stabilized liquid bridge networks in evaporative lithography and wet granular matter

KAUST Repository

Vakarelski, Ivan Uriev

2013-04-23

Evaporative lithography using latex particle templates is a novel approach for the self-assembly of suspension-dispersed nanoparticles into ordered microwire networks. The phenomenon that drives the self-assembly process is the propagation of a network of interconnected liquid bridges between the template particles and the underlying substrate. With the aid of video microscopy, we demonstrate that these liquid bridges are in fact the border zone between the underlying substrate and foam films vertical to the substrate, which are formed during the evaporation of the liquid from the suspension. The stability of the foam films and thus the liquid bridge network stability are due to the presence of a small amount of surfactant in the evaporating solution. We show that the same type of foam-film-stabilized liquid bridge network can also propagate in 3D clusters of spherical particles, which has important implications for the understanding of wet granular matter. © 2013 American Chemical Society.

Tear progression of symptomatic full-thickness and partial-thickness rotator cuff tears as measured by repeated MRI.

Science.gov (United States)

Kim, Yang-Soo; Kim, Sung-Eun; Bae, Sung-Ho; Lee, Hyo-Jin; Jee, Won-Hee; Park, Chang Kyun

2017-07-01

The purpose of this study was to analyse the natural course of symptomatic full-thickness and partial-thickness rotator cuff tears treated non-operatively and to identify risk factors affecting tear enlargement. One hundred and twenty-two patients who received non-surgical treatment for a partial- or full-thickness supraspinatus tear were included in this study. All rotator cuff tears were diagnosed with magnetic resonance imaging (MRI), and the same modality was used for follow-up studies. Follow-up MRI was performed after at least a 6-month interval. We evaluated the correlation between tear enlargement and follow-up duration. Eleven risk factors were analysed by both univariate and multivariate analyses to identify factors that affect enlargement of rotator cuff tears. The mean follow-up period was 24.4 ± 19.5 months. Out of 122 patients, 34 (27.9%) patients had an initial full-thickness tear and 88 (72.1%) patients had a partial-thickness tear. Considering all patients together, tear size increased in 51/122 (41.8%) patients, was unchanged in 65/122 (53.3%) patients, and decreased in 6/122 (4.9%) patients. Tear size increased for 28/34 (82.4%) patients with full-thickness tears and 23/88 (26.1%) patients with partial-thickness tears. From the two groups which were followed over 12 months, a higher rate of enlargement was observed in full-thickness tears than in partial-thickness tears (6-12 months, n.s.; 12-24 months, P = 0.002; over 24 months, P rotator cuff tears and 23/88 (26.1%) of symptomatic partial-thickness tears increased in size over a follow-up period of 6-100 months. Full-thickness tears showed a higher rate of enlargement than partial-thickness tears regardless of the follow-up duration. Univariate and multivariate analyses suggested that full-thickness tear was the most reliable risk factor for tear enlargement. The clinical relevance of these observations is that full-thickness rotator cuff tears treated conservatively should be

Low levels of 17-β-oestradiol, oestrone and testosterone correlate with severe evaporative dysfunctional tear syndrome in postmenopausal women: a case-control study.

Science.gov (United States)

Gagliano, Caterina; Caruso, Salvatore; Napolitano, Giuseppe; Malaguarnera, Giulia; Cicinelli, Maria Vittoria; Amato, Roberta; Reibaldi, Michele; Incarbone, Giuseppe; Bucolo, Claudio; Drago, Filippo; Avitabile, Teresio

2014-03-01

To evaluate the role of 17-β-oestradiol, oestrone and total testosterone (TT) deficiency in the pathogenesis of severe evaporative dry eye syndrome (DES), investigating the relationship between tear osmolarity, tear film break-up time (TF-BUT), Schirmer test and serum sex hormones in postmenopausal women. 44 postmenopausal women were recruited for a case-control study: 22 women with severe evaporative DES (Group A) and 22 without DES (Group B). The tests performed included laboratory blood analysis: fasting plasma profile (17-β-oestradiol, oestrone and TT), glucose level and lipid profile. Detailed eye examinations, including corneal and conjunctival staining, tear osmolarity measurement, tear volume and TF-BUT, were performed. The Ocular Surface Disease Index Questionnaire was also administered. Values of Schirmer test and TF-BUT in Group A were significantly lower in comparison with Group B (p<0.001). Serum levels of 17-β-oestradiol, oestrone and TT were significantly lower in Group A compared with Group B (p<0.05). In women with severe evaporative DES, the levels of 17-β-oestradiol, oestrone and TT were inversely correlated with the tear film osmolarity (r=-0.7, -0.88, -0.81, respectively). In postmenopausal women with severe evaporative DES, sex hormone levels are lower than control and that tear osmolarity is negatively correlated with sex hormone levels.

Analysis of Th17-associated cytokines in tears of patients with dry eye syndrome.

Science.gov (United States)

Tan, X; Sun, S; Liu, Y; Zhu, T; Wang, K; Ren, T; Wu, Z; Xu, H; Zhu, L

2014-05-01

To determine the levels of Th17-associated cytokines, particularly interleukin (IL)-17 and IL-22 in tears of patients with dry eye syndrome. Tear samples were collected from 20 healthy volunteers, 20 dry eye (DE) patients with non-Sjögren's syndrome (NSSDE) and 20 DE patients with Sjögren's syndrome (SSDE). Symptom questionnaire was self-administered and multiple dry eye disease (DED)-related clinical tests were performed. The levels of IL-17 and IL-22 in tears were measured by enzyme-linked immunosorbent assay. The levels of IL-17 and IL-22 were significantly increased in tears of DE patients compared with those of controls and also higher in SSDE patients compared with those of NSSDE patients (Ptear film break-up time and Schirmer I test in both NSSDE and SSDE patients (Ptears were significantly increased in DE patients, which were associated with the disease severity. Therefore, Th17 cell-associated cytokines, particularly IL-17 and IL-22, may have important roles in the immunopathogenesis of the DED.

Examination of rotator cuff re-tear

International Nuclear Information System (INIS)

Kitahara, Hiroyuki; Yabe, Yoshihiro; Norimatsu, Takahiro; Adachi, Shinji; Sera, Keisuke

2010-01-01

The six-month post-operative re-tear rate in 72 arthroscopic rotator cuff repair cases was 16.3% by MRI. The re-tear rate of massive tears was 50%. We investigated the details of the re-tears by MRI and arthroscopic findings. High re-tear rates were connected with cuff tear size and fatty degeneration of muscle belly. Cases with poor cuff quality in arthroscopically showed high re-tear rate. These results suggest that surgery operation should be performed as soon as possible after diagnosis of cuff tear to obtain good results. Cases with damage of long head of the biceps (LHB) are likely to develop impingement causes of re-tears. Some type of rehabilitation is required to avoid impingement in such cases. (author)

Structure, stability and electrochromic properties of polyaniline film covalently bonded to indium tin oxide substrate

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wenzhi, E-mail: zhangwz@xatu.edu.cn [Key Laboratory for Photoelectric Functional Materials and Devices of Shaanxi Province, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710021 (China); Ju, Wenxing; Wu, Xinming; Wang, Yan; Wang, Qiguan; Zhou, Hongwei; Wang, Sumin [Key Laboratory for Photoelectric Functional Materials and Devices of Shaanxi Province, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710021 (China); Hu, Chenglong [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, School of Chemistry and Environmental Engineering, Jianghan University, Wuhan 430056 (China)

2016-03-30

Graphical abstract: A chemical bonding approach was proposed to prepare the PANI film covalently bonded to ITO substrate and the film exhibited high electrochemical activities and stability compared with that obtained by conventional film-forming approach. - Highlights: • The PANI film covalently bonded to ITO substrate was prepared using ABPA as modifier. • The oxidative potentials of the obtained PANI film were decreased. • The obtained PANI film exhibits high electrochemical activities and stability. - Abstract: Indium tin oxide (ITO) substrate was modified with 4-aminobenzylphosphonic acid (ABPA), and then the polyaniline (PANI) film covalently bonded to ITO substrate was prepared by the chemical oxidation polymerization. X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and atomic force microscopy (AFM) measurements demonstrated that chemical binding was formed between PANI and ABPA-modified ITO surface, and the maximum thickness of PANI layer is about 30 nm. The adhesive strength of PANI film on ITO substrate was tested by sonication. It was found that the film formed on the modified ITO exhibited a much better stability than that on bare one. Cyclic voltammetry (CV) and UV–vis spectroscopy measurements indicated that the oxidative potentials of PANI film on ABPA-modified ITO substrate were decreased and the film exhibited high electrochemical activities. Moreover, the optical contrast increased from 0.58 for PANI film (without ultrasound) to 1.06 for PANI film (after ultrasound for 60 min), which had an over 83% enhancement. The coloration time was 20.8 s, while the bleaching time was 19.5 s. The increase of electrochromic switching time was due to the lower ion diffusion coefficient of the large cation of (C{sub 4}H{sub 9}){sub 4}N{sup +} under the positive and negative potentials as comparison with the small Li{sup +} ion.

What emotional tears convey : Tearful individuals are seen as warmer, but also as less competent

NARCIS (Netherlands)

van de Ven, Niels; Meijs, Maartje; Vingerhoets, A.J.J.M.

Earlier research found that the mere sight of tears promotes the willingness to provide support to the person shedding the tears. Other research, however, found that deliberate responses towards tearful persons could be more negative as well. We think this is because tears have ambivalent effects on

Effects of stabilizer ratio on photoluminescence properties of sol-gel ZnO nano-structured thin films

International Nuclear Information System (INIS)

Boudjouan, F.; Chelouche, A.; Touam, T.; Djouadi, D.; Khodja, S.; Tazerout, M.; Ouerdane, Y.; Hadjoub, Z.

2015-01-01

Nanostructured ZnO thin films with different molar ratios of MEA to zinc acetate (0.5, 1.0, 1.5 and 2.0) have been deposited on glass substrates by a sol–gel dip coating technique. X-ray diffraction, Scanning Electron Microscopy, UV–visible spectrophotometry and photoluminescence spectroscopy have been employed to investigate the effect of MEA stabilizer ratio on structural, morphological, absorbance and emission properties of the ZnO thin films. Diffraction patterns have shown that all the films are polycrystalline and exhibit a wurtzite hexagonal structure. The c axis orientation has been enhanced with increasing stabilizer ratio. SEM micrographs have revealed that the morphology of the ZnO films depend on stabilizer ratio. The UV–visible absorption spectra have demonstrated that the optical absorption is affected by stabilizer ratio. The photoluminescence spectra have indicated one ultraviolet and two visible emission bands (green and red), while band intensities are found to be dependent on stabilizer ratio. ZnO thin films deposited at MEA ratio of 1.0 show the highest UV emission while the minimum UV emission intensity is observed in thin films deposited at ratio of 0.5 and the maximum green has been recorded for films deposited at MEA ratio of 2.0. - Highlight: • c axis orientation increases with increasing MEA ratio. • The increase of MEA ration from 0.5 to 1.0 enhances greatly the UV emission. • The larger I UV /I visible is obtained for the MEA to Zn ratio of 1:1. • The MEA ratio of 0.5 favors the formation of large density of V zn . • The MEA ratio of 2.0 increases the V o density

Collisionless tearing mode reconnection at the dayside magnetopause of the earth's magnetosphere

International Nuclear Information System (INIS)

Quest, K.B.

1982-01-01

The purpose of this thesis was to determine if the collisionless tearing mode, a plasma instability, is a viable mechanism for interconnecting field lines at the dayside magnetopause. More generally, it was wished to test theoretically the assertion that collisionless tearing is a probable first step in cosmical reconnection. The procedure was to model the magnetopause as a local one-dimensional Vlasov equilibrium, and then calculate the linear and nonlinear stability properties of tearing and tearing-like oscillations. Quantitative estimates of the range of plasma parameter space over which significant growth occurs were obtained. Assuming that significant tearing mode growth implies significant reconnection, conditions were determined for which tearing will be important to dayside reconnection. Linearly it was found that the growth rate is relatively insensitive to the temperature of the species, but depends sensitively on (1) the thickness of the magnetopause current, (2) the number density at the location of the singular layer, and (3) the magnitude of the magnetic shear. For significant linear growth the magnetopause half-sheet thickness was required to be on the order of or less than a thermal ion gyroradius, the number density was required to be no more than 100 cm - 3 , and the magnetosheath field was required to be locally antialigned with the magnetospheric field. If the above conditions are met, which are stringent but not impossible, the mode will linearly amplify. Another topic examined is the question of the structure of the tearing eigenmodes at the dayside magnetopause. By considering finite transit time effects on electron Landau resonance it was concluded that magnetopause tearing turbulence probably occurs in spatially bounded wave packets

The flow and hydrodynamic stability of a liquid film on a rotating disc

International Nuclear Information System (INIS)

Kim, Tae-Sung; Kim, Moon-Uhn

2009-01-01

The flow of a liquid film on a rotating disc is investigated in the case where a liquid is supplied at a constant flow rate. We propose thin film equations by the integral method with a simple approach to satisfy the boundary conditions on a disc and a free surface, and the results are compared with those of the Navier-Stokes equations. The radial film velocity is assumed to be a quartic profile in our analysis, whereas it was assumed to be a quadratic one, neglecting the inertia force so that the boundary conditions were not completely satisfied, in the analysis of Sisoev et al (2003 J. Fluid Mech. 229 531-54). The basic flow and its stability are analyzed using the thin film equations even in the region where the inertia force is not negligible. A local stability analysis of the flow is conducted using the linearized disturbance equations and correctly predicts Needham's simple instability criterion. The present thin film equations give a good approximation of the Navier-Stokes equations.

Assessment of lamellar tearing

International Nuclear Information System (INIS)

McEnerney, J.W.

1978-03-01

Information on lamellar tearing is summarized and related to proposed ASME Code requirements. Lamellar tearing is characterized as a complex phenomenon related to poor short transverse ductility and through-thickness strain. The material, welding, and design variables that affect lamellar tearing are shown to be complex and interrelated. The commonly reported tests for assessing material susceptibility are described, with the controversy over their validity being carefully detailed. Although the use of a nondestructive test such as ultrasonic examination is most desirable, a widely applicable test method does not appear to be available. Of the destructive tests, the short transverse tensile reduction-of-area currently offers the most applicable means of assessing material susceptibility. However, because of the importance of matrix toughness, the short transverse Charpy V-notch test should be considered for use as an additional test if acceptance limits are developed. The ultrasonic detection of lamellar tears is susceptible to interpretation errors, which can make it overly conservative and lead to unnecessary repairs. The repair of tears is described as costly, difficult, and sometimes ineffective. Current design requirements appear to preclude any failures during static and fatigue service loads. However, without improvement of short transverse ductility, certain dynamic service loads could cause lamellar tearing failures. Two alternate design paths are recommended to prevent tearing during fabrication or service loading. The current and proposed ASME requirements dealing with lamellar tearing are reviewed and recommendations are made

Anterior Cruciate Ligament Tear: Reliability of MR Imaging to Predict Stability after Conservative Treatment

Energy Technology Data Exchange (ETDEWEB)

Chung, Hye Won; Ahn, Jin Hwan; Ahn, Joong Mo; Yoon, Young Cheol; Hong, Hyun Pyo; Yoo, So Young; Kim, Seon Woo [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2007-06-15

The aim of this study is to evaluate the reliability of MR imaging to predict the stability of the torn anterior cruciate ligament (ACL) after complete recovery of the ligament's continuity. Twenty patients with 20 knee injuries (13 males and 7 females; age range, 20 54) were enrolled in the study. The inclusion criteria were a positive history of acute trauma, diagnosis of the ACL tear by both the physical examination and the MR imaging at the initial presentation, conservative treatment, complete recovery of the continuity of the ligament on the follow up (FU) MR images and availability of the KT-2000 measurements. Two radiologists, who worked in consensus, graded the MR findings with using a 3-point system for the signal intensity, sharpness, straightness and the thickness of the healed ligament. The insufficiency of ACL was categorized into three groups according to the KT-2000 measurements. The statistic correlations between the grades of the MR findings and the degrees of ACL insufficiency were analyzed using the Cochran-Mantel-Haenszel test (p < 0.05). The p-values for each category of the MR findings according to the different groups of the KT-2000 measurements were 0.9180 for the MR signal intensity, 1.0000 for sharpness, 0.5038 for straightness and 0.2950 for thickness of the ACL. The MR findings were not significantly different between the different KT-2000 groups. MR imaging itself is not a reliable examination to predict stability of the ACL rupture outcome, even when the MR images show an intact appearance of the ACL.

Effects of H-implantation energy on the optical stability of implanted usher films under photo-irradiation

International Nuclear Information System (INIS)

Awazu, K.; Yasui, H.; Kasamori, M.; Ichikawa, T.; Funada, Y.; Iwaki, M.

1999-01-01

A study has been made on the improvement of the optical stability of urushi films under optical irradiation using ion implantation. Ion implantation of hydrogen ions in urushi films was performed with a dose of 10 15 ions/cm 2 at ion energies ranging from 0.2 to 150 keV at room temperature. The photo-irradiation onto the urushi films was carried out at irradiation energies ranging from 40 to 400 MJ/m 2 . H-implantation onto urushi films is useful for improving the optical stability under photo-irradiation when the implantation energy is larger than 60 keV

Metastable Electrical Characteristics of Polycrystalline Thin-Film Photovoltaic Modules upon Exposure and Stabilization: Preprint

Energy Technology Data Exchange (ETDEWEB)

Deline, C. A.; del Cueto, J. A.; Albin, D. S.; Rummel, S. R.

2011-09-01

The significant features of a series of stabilization experiments conducted at the National Renewable Energy Laboratory (NREL) between May 2009 and the present are reported. These experiments evaluated a procedure to stabilize the measured performance of thin-film polycrystalline cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) thin-film photovoltaic (PV) modules. The current-voltage (I-V) characteristics of CdTe and CIGS thin-film PV devices and modules exhibit transitory changes in electrical performance after thermal exposure in the dark and/or bias and light exposures. We present the results of our case studies of module performance versus exposure: light-soaked at 65 degrees C; exposed in the dark under forward bias at 65 degrees C; and, finally, longer-term outdoor exposure. We find that stabilization can be achieved to varying degrees using either light-soaking or dark bias methods and that the existing IEC 61646 light-soaking interval may be appropriate for CdTe and CIGS modules with one caveat: it is likely that at least three exposure intervals are required for stabilization.

Tear dynamics in healthy and dry eyes.

Science.gov (United States)

Cerretani, Colin F; Radke, C J

2014-06-01

Dry-eye disease, an increasingly prevalent ocular-surface disorder, significantly alters tear physiology. Understanding the basic physics of tear dynamics in healthy and dry eyes benefits both diagnosis and treatment of dry eye. We present a physiological-based model to describe tear dynamics during blinking. Tears are compartmentalized over the ocular surface; the blink cycle is divided into three repeating phases. Conservation laws quantify the tear volume and tear osmolarity of each compartment during each blink phase. Lacrimal-supply and tear-evaporation rates are varied to reveal the dependence of tear dynamics on dry-eye conditions, specifically tear osmolarity, tear volume, tear-turnover rate (TTR), and osmotic water flow. Predicted periodic-steady tear-meniscus osmolarity is 309 and 321 mOsM in normal and dry eyes, respectively. Tear osmolarity, volume, and TTR all match available clinical measurements. Osmotic water flow through the cornea and conjunctiva contribute 10 and 50% to the total tear supply in healthy and dry-eye conditions, respectively. TTR in aqueous-deficient dry eye (ADDE) is only half that in evaporative dry eye (EDE). The compartmental periodic-steady tear-dynamics model accurately predicts tear behavior in normal and dry eyes. Inclusion of osmotic water flow is crucial to match measured tear osmolarity. Tear-dynamics predictions corroborate the use of TTR as a clinical discriminator between ADDE and EDE. The proposed model is readily extended to predict the dynamics of aqueous solutes such as drugs or fluorescent tags.

Posterior horn lateral meniscal tears simulating meniscofemoral ligament attachment in the setting of ACL tear: MRI findings

International Nuclear Information System (INIS)

Park, Lawrence S.; Jacobson, Jon A.; Jamadar, David A.; Caoili, Elaine; Kalume-Brigido, Monica; Wojtys, Edward

2007-01-01

We have noted apparent far lateral meniscal attachment of the meniscofemoral ligament (MFL) with an anterior cruciate ligament (ACL) tear. This study evaluates MFL attachment and association with posterior horn lateral meniscus (PHLM) tear. Nine months of knee arthroscopy reports were reviewed to classify the PHLM and ACL as torn or normal. After excluding those with prior knee surgery, MR images were reviewed by two radiologists to determine the number of images lateral to PCL, which showed the ligaments of Humphrey and Wrisberg visible as structures separate from the PHLM. Any patient with abnormal PHLM surface signal not continuous with the MFL was excluded. MRI findings were compared with arthroscopy using Student's t test and Fisher's exact test. Of the 54 participants, 5 had PHLM tears and 49 were normal. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. The ligament of Humphrey inserted on average 0.9 consecutive images lateral to the PCL without an PHLM tear and 4.7 with an PHLM tear; the ligament of Wrisberg inserted on average 3.0 consecutive images without an PHLM tear and 4.5 with an PHLM tear (slice thickness/gap = 3 mm/0.5 mm). There was a significant association between PHLM tear and number of images (p = 0.0028), and between ACL tear and this type of PHLM tear (p = 0.0064). Apparent far lateral meniscal extension of a meniscofemoral ligament (greater than or equal to four images lateral to the PCL) should be considered as a possible PHLM tear, especially in the setting of an ACL tear. (orig.)

Properties, ageing behavior and stability of bipolar films containing nano-layers of allylamine and acrylic acid plasma polymers

Science.gov (United States)

Aziz, Gaelle; Asadian, Mahtab; Declercq, Heidi; Morent, Rino; De Geyter, Nathalie

2018-06-01

In this work, a dielectric barrier discharge (DBD) has been used for the deposition of bipolar films containing alternating nano-layers of plasma polymerized allylamine (PPAam) and acrylic acid (PPAac). Various films were obtained by varying the single-layer thickness of each plasma polymer while maintaining a constant total film thickness and two kinds of films were fabricated via different depositing sequences (PPAam/Aac and PPAac/Aam). Films properties, ageing in air and stability in water over a 7 days period were investigated. Results showed that, COO- and NH3+ polar entities, generated from the interaction of PPAam and PPAac, are present in the bipolar films. Concerning the films stability, the different reaction mechanisms involved in the formation of each kind of films resulted in a higher amount of polar groups in the PPAam/Aac films; this conferred these films a higher stability than PPAac/Aam. Concerning the films ageing behavior, all prepared samples underwent some kind of ageing which was found to be dependent on the deposition sequence. Results also showed that bipolar coatings exhibited better cell-material interactions compared to PPAam and PPAac films; with a better cell viability observed on PPAam/Aac coatings after 1 and 7 days culture.

Fabrication of Yttria stabilized zirconia thin films on poroussubstrates for fuel cell applications

Energy Technology Data Exchange (ETDEWEB)

Leming, Andres [Univ. of California, Berkeley, CA (United States)

2003-06-16

A process for the deposition of yttria stabilized zirconia (YSZ) films, on porous substrates, has been developed. These films have possible applications as electrolyte membranes in fuel cells. The films were deposited from colloidal suspensions through the vacuum infiltration technique. Films were deposited on both fully sintered and partially sintered substrates. A critical cracking thickness for the films was identified and strategies are presented to overcome this barrier. Green film density was also examined, and a method for improving green density by changing suspension pH and surfactant was developed. A dependence of film density on film thickness was observed, and materials interactions are suggested as a possible cause. Non-shorted YSZ films were obtained on co-fired substrates, and a cathode supported solid oxide fuel cell was constructed and characterized.

Software Simulation of Hot Tearing

DEFF Research Database (Denmark)

Andersen, S.; Hansen, P.N.; Hattel, Jesper Henri

1999-01-01

The brittleness of a solidifying alloy in a temperature range near the solidus temperature has been recognised since the fifties as the mechanism responsible for hot tearing. Due to this brittlenes, the metal will crack under even small amounts of strain in that temperature range. We see these hot...... tears in castings close to hot centres, where the level of strain is often too high.Although the hot tearing mechanism is well understood, until now it has been difficult to do much to reduce the hot tearing tendency in a casting. In the seventies, good hot tearing criteria were developed by considering...... the solidification rate and the strain rate of the hot tear prone areas. But, until recently it was only possible to simulate the solidification rate, so that the criteria could not be used effectively.Today, with new software developments, it is possible to also simulate the strain rate in the hot tear prone areas...

Efficacy of an artificial tear emulsion in patients with dry eye associated with meibomian gland dysfunction

Directory of Open Access Journals (Sweden)

Sindt CW

2013-08-01

Full Text Available Christine W Sindt,1 Gary N Foulks2 1Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, IA, 2Kentucky Lions Eye Center, Department of Ophthalmology and Visual Science, University of Louisville, Louisville, KY, USA Objectives: The aim of the study reported here was to assess the efficacy of an artificial tear emulsion for the treatment of dry eye associated with meibomian gland dysfunction (MGD. Methods: At five clinics, patients completed a 1-week treatment with their habitual topical therapy and then a 4-week treatment with open-label study medication: Systane® Balance Lubricant Eye Drops (Alcon, Alcon Inc, Fort Worth, TX, USA. Subjective assessments included a preference survey, the Impact of Dry Eye in Everyday Life questionnaire, and the Work Productivity and Activity Impairment questionnaire. Objective assessments by unmasked investigators included visual acuity, meibomian gland expression and dropout, tear film breakup time, corneal staining, and dosing frequency. Results: At baseline, the 49 patients had mean meibomian gland expression grades and gland dropout that indicated mild to moderate MGD. Patients administered their habitual therapy 2.5 ± 1.3 times per day. After 4 weeks of study medication, the Impact of Dry Eye in Everyday Life questionnaire results indicated statistically and clinically significant improvements. Fewer than half of the participants were employed, limiting the usefulness of the Work Productivity and Activity Impairment questionnaire. Visual acuity remained statistically similar, while corneal staining and tear film breakup time improved significantly (P < 0.05 but modestly. The outcomes were achieved with 1.9 ± 1.1 doses per day of study medication, a significantly lower frequency than the habitual frequency (P < 0.001. The most common medication-related adverse event was blurred vision (3/49 patients, 6.1%. At study conclusion, 27/44 (61.4% survey respondents

Tear osmolarity measurements in dry eye related to primary Sjögren's syndrome.

Science.gov (United States)

Utine, Canan Asli; Bıçakçıgil, Müge; Yavuz, Sule; Çiftçi, Ferda

2011-08-01

To evaluate the tear osmolarity in patients with dry eye syndrome related to primary Sjögren's Syndrome (SS). Twenty eyes of 10 patients with dry eye and primary SS (Group 1) and 20 eyes of 20 subjects who do not have dry eye syndrome (Group 2) were included in this cross-sectional study. In all eyes, ophthalmic examination was performed in the same order: International Ocular Surface Disease Index survey, visual acuity assessment, conjunctival hyperemia scoring, tear osmolarity measurement with TearLab(™) Osmolarity System, tear film break-up time assessment, corneal fluorescein staining scoring, ocular surface Lissamine Green staining scoring, anesthetized Schirmer test. Dry eye severity was graded according to Dry Eye Workshop (DEWS) classification system. Four eyes with grade 1, four eyes with grade 2, seven eyes with grade 3, and five eyes with grade 4 dryness, according to DEWS system, were included. The mean tear osmolarity value was 301.9 ± 11.40 mOsm/L (range: 290-328) in Group 1, and 294.85 ± 8.33 mOsm/L (range: 283-311) in Group 2 (p = 0.03). In Group 1, tear osmolarity values were positively correlated with OSDI scores (r(18) = 0.55, r(2) = 0.31, p = 0.01), DEWS classification grades (r(18) = 0.73, r(2) = 0.54, p dry eye syndrome related to primary SS compared to control subjects, and positively correlated with the severity of dry eye.

Film Grain-Size Related Long-Term Stability of Inverted Perovskite Solar Cells.

Science.gov (United States)

Chiang, Chien-Hung; Wu, Chun-Guey

2016-09-22

The power conversion efficiency (PCE) of the perovskite solar cell is high enough to be commercially viable. The next important issue is the stability of the device. This article discusses the effect of the perovskite grain-size on the long-term stability of inverted perovskite solar cells. Perovskite films composed of various sizes of grains were prepared by controlling the solvent annealing time. The grain-size related stability of the inverted cells was investigated both in ambient atmosphere at relative humidity of approximately 30-40 % and in a nitrogen filled glove box (H 2 Operovskite film having the grain size larger than 1 μm (D-10) decreases less than 10 % with storage in a glove box and less than 15 % when it was stored under an ambient atmosphere for 30 days. However, the cell using the perovskite film composed of small (∼100 nm) perovskite grains (D-0) exhibits complete loss of PCE after storage under the ambient atmosphere for only 15 days and a PCE loss of up to 70 % with storage in the glove box for 30 days. These results suggest that, even under H 2 O-free conditions, the chemical- and thermal-induced production of pin holes at the grain boundaries of the perovskite film could be the reason for long-term instability of inverted perovskite solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Systematic design and simulation of a tearing mode suppression feedback control system for the TEXTOR tokamak

International Nuclear Information System (INIS)

Hennen, B.A.; Westerhof, E.; De Baar, M.R.; Nuij, P.W.J.M.; Steinbuch, M.

2012-01-01

Suppression of tearing modes is essential for the operation of tokamaks. This paper describes the design and simulation of a tearing mode suppression feedback control system for the TEXTOR tokamak. The two main control tasks of this feedback control system are the radial alignment of electron cyclotron resonance heating and current drive (ECRH/ECCD) with a tearing mode and the stabilization of a mode at a specific width. In order to simulate these control tasks, the time evolution of a tearing mode subject to suppression by ECRH/ECCD and destabilization by a magnetic perturbation field is modelled using the generalized Rutherford equation. The model includes an equilibrium model and an ECRH/ECCD launcher model. The dynamics and static equilibria of this model are analysed. The model is linearized and based on the linearized model, linear feedback controllers are designed and simulated, demonstrating both alignment and width control of tearing modes in TEXTOR. (paper)

Phase coexistence in thin liquid films stabilized by colloidal particles: equilibrium and non-equilibrium properties

International Nuclear Information System (INIS)

Blawzdziewicz, J.; Wajnryb, E.

2005-01-01

Phase equilibria between regions of different thickness in thin liquid films stabilized by colloidal particles are investigated using a quasi-two-dimensional thermodynamic formalism. Appropriate equilibrium conditions for the film tension, normal pressure, and chemical potential of the particles in the film are formulated, and it is shown that the relaxation of these parameters occurs consecutively on three distinct time scales. Film stratification is described quantitatively for a hard-sphere suspension using a Monte-Carlo method to evaluate thermodynamic equations of state. Coexisting phases are determined for systems in constrained- and full-equilibrium states that correspond to different stages of film relaxation. We also evaluated the effective viscosity coefficients for two-dimensional compressional and shear flows of a film and the self and collective mobility coefficients of the stabilizing particles. The hydrodynamic calculations were performed using a multiple-reflection representation of Stokes flow between two free surfaces. In this approach, the particle-laden film is equivalent to a periodic system of spheres with a unit cell that is much smaller in the transverse direction than in the lateral direction. (author)

Antioxidant and inflammatory cytokine in tears of patients with dry eye syndrome treated with preservative-free versus preserved eye drops.

Science.gov (United States)

Jee, Donghyun; Park, Sang Hee; Kim, Man Soo; Kim, Eun Chul

2014-07-03

To compare the antioxidant and inflammatory cytokine activities in tears of patients with dry eye syndrome treated with preservative-free versus preserved eye drops. A total of 100 patients with moderate to severe dry eye syndrome were randomly divided into two groups. Fifty patients (group 1) were treated four times with preservative-free 0.1% sodium hyaluronate and 0.1% fluorometholone eye drops in the first month and with preservative-free 0.1% sodium hyaluronate and 0.05% cyclosporine eye drops in the second and third months. Another 50 patients (group 2) were treated with preserved eye drops on the same schedule. Ocular Surface Disease Index, corneal fluorescein staining, Schirmer I test, tear film breakup time, impression cytology, and antioxidant and inflammatory cytokine activities in tears were evaluated. Treatment with preservative-free eye drops led to significant improvements in symptoms, tear film breakup time, Schirmer I score, and impression cytologic findings compared to treatment with preserved eye drops (P dry eye syndrome. There was a statistically significant decrease in the IL-1β, IL-6, IL-12, and TNF-α concentrations and a statistically significant increase in the catalase, peroxiredoxin 2, superoxide dismutase 2 (SOD 2), and thioredoxin mean fluorescence intensity (MFI) of tears in the preservative-free group at 1, 2, and 3 months compared to initial values, respectively (P eye drops is effective against the dry eye syndrome. Preservative-free eye drops seem to be more effective than preserved eye drops in decreasing ocular inflammation and in increasing antioxidant contents in tears of patients with dry eye syndrome. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Classification of ulnar triangular fibrocartilage complex tears. A treatment algorithm for Palmer type IB tears.

Science.gov (United States)

Atzei, A; Luchetti, R; Garagnani, L

2017-05-01

The classical definition of 'Palmer Type IB' triangular fibrocartilage complex tear, includes a spectrum of clinical conditions. This review highlights the clinical and arthroscopic criteria that enable us to categorize five classes on a treatment-oriented classification system of triangular fibrocartilage complex peripheral tears. Class 1 lesions represent isolated tears of the distal triangular fibrocartilage complex without distal radio-ulnar joint instability and are amenable to arthroscopic suture. Class 2 tears include rupture of both the distal triangular fibrocartilage complex and proximal attachments of the triangular fibrocartilage complex to the fovea. Class 3 tears constitute isolated ruptures of the proximal attachment of the triangular fibrocartilage complex to the fovea; they are not visible at radio-carpal arthroscopy. Both Class 2 and Class 3 tears are diagnosed with a positive hook test and are typically associated with distal radio-ulnar joint instability. If required, treatment is through reattachment of the distal radio-ulnar ligament insertions to the fovea. Class 4 lesions are irreparable tears due to the size of the defect or to poor tissue quality and, if required, treatment is through distal radio-ulnar ligament reconstruction with tendon graft. Class 5 tears are associated with distal radio-ulnar joint arthritis and can only be treated with salvage procedures. This subdivision of type IB triangular fibrocartilage complex tear provides more insights in the pathomechanics and treatment strategies. II.

Tearing mode of a neutral current sheath in a plasma flux

International Nuclear Information System (INIS)

Gubchenko, V.M.

1982-01-01

The linear stage of the tearing mode of diffusion neutral current sheath immersed in the plasma flux directed along the magnetic field is considered. It follows form the obtained dispersion characteristics that the flux exerts a stabilizing effect on the mode and leads to appearance of phase drift velocity

Effects of punctal occlusion on global tear proteins in patients with dry eye.

Science.gov (United States)

Tong, Louis; Zhou, Lei; Beuerman, Roger; Simonyi, Susan; Hollander, David A; Stern, Michael E

2017-10-01

To investigate effects of punctal occlusion on global tear protein levels in patients with dry eye. In this prospective, longitudinal, single-center study, nonabsorbable punctal plugs were inserted bilaterally into the lower punctum of 30 patients with moderate dry eye. Dry eye symptoms, fluorescein corneal staining, Schirmer I test, tear film break-up time, and safety were assessed in the more severely affected eye. Tear proteins at weeks 1 and 3 were quantified by iTRAQ relative to baseline preocclusion levels. Of 29 patients who completed the study, 23 (mean age 49.8 years) had sufficient tear samples for analysis. After 3 weeks, punctal occlusion significantly upregulated tear proteins, including glutathione synthase (mean of 1.6-fold, P = 0.01) and interleukin-1 receptor antagonist (1.7-fold, P = 0.032) and downregulated cholinergic receptor (neuronal) alpha-7 (0.79-fold, P = 0.039) and lymphocyte cytosolic protein-1 (0.66-fold, P = 0.012). Clustering analysis of global tear proteins revealed two clear profile changes; the first group of patients (cluster 1, n = 10) had a reduction in the inflammatory proteins (e.g., S100A8) and rise in lacrimal proteins supporting the ocular surface (e.g., lysozyme), whereas the second group (cluster 2, n = 13) had an increase in inflammatory proteins and a decrease in lacrimal proteins. Logistic regression analysis revealed that cluster 1 patients had significantly (P = 0.006) lower Schirmer scores at baseline (mean [standard deviation]: 4.3 [4.3] mm) than cluster 2 (6.8 [2.6] mm). Punctal plugs produced a beneficial pattern of tear protein change in patients with relatively low Schirmer scores within 3 weeks of punctal occlusion. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Photocatalytic activity and stability of TiO{sub 2} and WO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Carcel, Radu Adrian; Andronic, Luminita, E-mail: andronic-luminita@unitbv.ro; Duta, Anca, E-mail: a.duta@unitbv.ro

2012-08-15

Photocatalysis represents a viable option for complete degrading the dye molecules resulted in the textile industry, up to products that do not represent environmental threats. The photocatalytic degradation of methyl orange has been investigated using TiO{sub 2}, WO{sub 3} and mixed thin films. The photodegradation efficiency is examined in correlation with the experimental parameters (irradiation time, H{sub 2}O{sub 2} addition and stability), along with the morphology and crystallinity data. The H{sub 2}O{sub 2} addition increases the photodegradation efficiency by providing additional hydroxyl groups and further reducing the recombination of the electron-hole pairs by reacting with the electrons at the catalyst interface. To test the stability of the photocatalytic films in long time running processes, batch series of experiments were conducted using contact periods up to 9 days. The results show that the thin films maintained their photocatalytic properties confirming their stability and viability for up-scaling. Highlights: Black-Right-Pointing-Pointer TiO{sub 2}, WO{sub 3} and mixed thin films Black-Right-Pointing-Pointer We tested the photocatalytic activity and photocatalyst stability over a period up to 9 days of continuous irradiation. Black-Right-Pointing-Pointer The influence of medium pH and oxidizing agent (H{sub 2}O{sub 2}) was analyzed.

Facilitation of tear fluid secretion by 3% diquafosol ophthalmic solution in normal human eyes.

Science.gov (United States)

Yokoi, Norihiko; Kato, Hiroaki; Kinoshita, Shigeru

2014-01-01

To evaluate the increase in tear fluid volume induced by 3% diquafosol ophthalmic solution in normal human eyes. Prospective, randomized, double-masked, comparative study. Twenty healthy adults (17 males and 3 females; mean age, 38.8 years) underwent topical instillation of 2 ophthalmic solutions, artificial tears in 1 eye and 3% diquafosol ophthalmic solution in the fellow eye, in a masked manner. The radius of curvature of the central lower tear meniscus was measured at 5, 10, 15, 30, and 60 minutes after instillation by use of reflective meniscometry, and subjects' self-evaluated symptoms of wetness and stinging using a visual analog scale. Changes after instillation in the radius of curvature from baseline (artificial tear group vs diquafosol group; mean ± standard error of the mean) were as follows: at 5 minutes, -0.008 ± 0.012 vs 0.045 ± 0.013; at 10 minutes, 0.001 ± 0.014 vs 0.057 ± 0.016; at 15 minutes, -0.012 ± 0.014 vs 0.037 ± 0.019; at 30 minutes, -0.010 ± 0.016 vs 0.030 ± 0.025; and at 60 minutes, -0.029 ± 0.012 vs -0.020 ± 0.012. The diquafosol group showed significantly greater values from 5 to 30 minutes after instillation. Of the 40 eyes, 13 showed abnormal tear film breakup time (≤5 seconds). The diquafosol group had significantly more wetness at 15 minutes after instillation than did the artificial tear group. Topical instillation of 3% diquafosol ophthalmic solution increases tear fluid on the ocular surface for up to 30 minutes in normal human eyes. Copyright © 2014 Elsevier Inc. All rights reserved.

Physical stability and moisture sorption of aqueous chitosan-amylose starch films plasticized with polyols

DEFF Research Database (Denmark)

Cervera, Mirna Fernández; Karjalainen, Milja; Airaksinen, Sari

2004-01-01

The short-term stability and the water sorption of films prepared from binary mixtures of chitosan and native amylose maize starch (Hylon VII) were evaluated using free films. The aqueous polymer solutions of the free films contained 2% (w/w) film formers, glycerol, or erythritol as a plasticizer...... in the crystallinity of the films are evident within a 3-month period of storage, and the changes in the solid state are dependent on the plasticizer and storage conditions. When stored at ambient conditions for 3 months, the aqueous chitosan-amylose starch films plasticized with erythritol exhibited a partly...

Tearing instability in cylindrical plasma configuration

International Nuclear Information System (INIS)

Zelenyj, L.M.

1979-01-01

The effect of the neutral-layer cylindrical geometry on the development of the tearing instability has been investigated in detail. The increments of the instability for all the regimes have been found. The influence of cylindrical effects becomes manifesting itself at small, as compared to the layer characteristic thickness, distances from the axis, and, finally, the electron regime of the instability development transforms into an ion one. The results obtained are of interest for studying the plasma stability in the devices of the ''Astron'' type and in magnetospheres of cosmic objects

EXAFS study of the stability of amorphous TbFe thin films

International Nuclear Information System (INIS)

Samant, M.G.; Marinero, E.E.; Robinson, C.; Cargill, G.S.

1989-01-01

This paper discusses the measurement of the local atomic structure of Fe in Au doped Tb-Fe thin film alloys by the use of EXAFS. The as deposited sample shows structural features which are essentially identical to those of the undoped films. Au additions stabilizes the amorphous structure against recrystallization, however, the loss of magnetic anisotropy under thermal annealing is not reduced. This demonstrates that magnetic relaxation in these alloys does not involve crystallization of the amorphous structure

Treatment of the Cornea Using Transcytotic Delivery into the Tear Film

Science.gov (United States)

2015-12-01

following popular refractive proce- dures, such as photorefractive keratectomy ( PRK ) and laser in situ keratomileusis ( LASIK ), directly rely on the...chronic inflammation of the eyelid) vs . normal tears [9]. LG-targeted delivery of this therapeutic within our novel delivery system is chosen for...particle compared to SI. If so, this might result from a larger hydro- philic fraction for KSI (66% vs . 48% for SI), which could result in a larger radius of

Idiopathic Bilateral Bloody Tearing

Directory of Open Access Journals (Sweden)

Emrullah Beyazyıldız

2015-01-01

Full Text Available Bloody tear is a rare and distinct clinic phenomenon. We report a case presenting with the complaint of recurrent episodes of bilateral bloody tearing. A 16-year-old girl presented to our clinic with complaint of bloody tearing in both eyes for 3 months. Bloody tearing was not associated with her menses. A blood-stained discharge from the punctum was not observed during the compression of both nasolacrimal ducts. Nasolacrimal passage was not obstructed. Imaging studies such as dacryocystography and gradient-echo magnetic resonance imaging (MRI of nasolacrimal canal were normal. Intranasal endoscopic evaluation was normal. We collected samples from bloody tears two times and pathological examination was performed. Pathological analysis showed lots of squamous cells and no endometrial cells; dysplastic cells were found. Further evaluations for underlying causes were unremarkable. No abnormalities were found in ophthalmologic, radiologic, and pathologic investigations. This condition is likely a rare abnormality and the least recognized aetiology for the idiopathic phenomenon.

Percentage Level of Tannin fur Rabbit for Leather Concerning Stitch Tearing Strength, Tearing Strength and Flexibility

Directory of Open Access Journals (Sweden)

Mustakim Mustakim

2012-02-01

Full Text Available The purpose of this study was to find out the appropriate of tannin level for rabbit fur leather concerning stitch tearing strength, tearing strength, and flexibility. The result were expected to contribute good information for the society, leather craftsman, and further researchers about fur leather tanning especially rabbit fur leather with tannin concerning stitch tearing strength, tearing strength and flexibility. The material that used were 12 pieces of four months of rabbit skin. The research method was Completely Randomized Design, consist of three treatments of tannin, they were: M1 (mimosa 15%, M2 (mimosa 20%, and M3 (mimosa 25%. Each of treatment hold on four repetition, the variables which measured were stitch tearing strength, tearing strength, and flexibility of fur leather. Data were  analysed by analysis variance followed by Duncan’s Multiple Range Test. The result of this research indicate that the use level of tannin give significant influence (P<0.05 among stitch tearing strength, tearing strength. It gave a very significant influence (P<0.01 for flexibility of rabbit fur leather. Based on the result, can be concluded that 25 % of tannin (mimosa, produce the best  result on stitch tearing strength and tearing strength. The increase of tannin offer will decrease the flexibility of fur leather but the lowest tannin produced the best flexibility of fur leather (15 percent. The best quality of rabbit fur leather produced by 25 % of tannin.   Keywords : leather, tannin, quality

[Neuronal and hormonal regulatory mechanisms of tears production and secretion].

Science.gov (United States)

Mrugacz, Małgorzata; Zywalewska, Nella; Bakunowicz-Lazarczyk, Alina

2005-01-01

The ocular surface, tear film, lacrimal glands act as a functional unit to preserve the quality of the refractive surface of the eye, and to resist injury and protect the eye against bodily and environmental conditions. Homeostasis of this functional unit involves neuronal and hormonal regulatory mechanisms. The eye appears to be a target organ for sex hormones particulary the androgen, as they modulate the immune system and trophic functions of the lacrimal and Meibomian glands.

Improved damp heat stability of Ga-Doped ZnO thin film by pretreatment of the polyethylene terephthalate substrate

Science.gov (United States)

Kim, B. B.; Seo, S. G.; Lim, Y. S.; Choi, H.-S.; Seo, W.-S.; Park, H.-H.

2013-09-01

A study on the damp heat stability of transparent conducting ZnO thin film grown on a polyethylene terephthalate substrate (PET) is reported. By thermal annealing of the PET substrate at 100°C with Ar flow in a vacuum chamber prior to the sputtering growth of Ga-doped ZnO (GZO) thin film, significantly enhanced damp heat stability was achieved at 60°C with a 90% relative humidity. Electrical and structural characterizations of the GZO thin films were carried out and the effects of the pretreatment on the improved damp heat stability are discussed.

Artificial tears potpourri: a literature review

Science.gov (United States)

Moshirfar, Majid; Pierson, Kasey; Hanamaikai, Kamalani; Santiago-Caban, Luis; Muthappan, Valliammai; Passi, Samuel F

2014-01-01

Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived. PMID:25114502

Stabilization of thin liquid films by repulsive van der waals force

KAUST Repository

Li, Erqiang; Vakarelski, Ivan Uriev; Chan, Derek Y C; Thoroddsen, Sigurdur T

2014-01-01

Using high-speed video recording of bubble rise experiments, we study the stability of thin liquid films trapped between a rising bubble and a surfactant-free liquid-liquid meniscus interface. Using different combinations of nonpolar oils and water

Enhancement of Moisture Protective Properties and Stability of Pectin through Formation of a Composite Film: Effects of Shellac and Plasticizer.

Science.gov (United States)

Luangtana-Anan, Manee; Soradech, Sitthiphong; Saengsod, Suthep; Nunthanid, Jurairat; Limmatvapirat, Sontaya

2017-12-01

The aim of this investigation was to develop the high moisture protective ability and stable pectin through the design of composite films based on varying shellac concentrations. A film casting method was applied to prepare a free film. The moisture protective properties and mechanical properties were investigated. The findings was the composite films exhibited the reductions in the hydrophilicity, water vapor permeability, and the moisture content compared with pectin films. The single and composite films were then study for their stability at 40 °C and 75% RH for 90 d. Among the concentrations of shellac, 50% (w/w) could improve stability in terms of moisture protection after 90 d of storage, whereas lower concentrations of shellac (10% to 40%) could not achieve this. However, the higher shellac content also contributed to weaker mechanical properties. The mechanical improvement and stability of composite films with the incorporation of plasticizers were further investigated. Polyethylene glycol 400 and diethyl phthalate at a concentration of 10% were used. The results indicated that both plasticizers could enhance the mechanical characteristics and had a slight effect on moisture protection. The stability of pectin in terms of moisture protective properties could, therefore, be modified through the fabrication of composite films with hydrophobic polymers, that is, shellac and the addition of proper plasticizers to enhance mechanical properties, which could offer wide applications for edible film in food, agro, and pharmaceutical industries. The composite film with 50% shellac could improve moisture protective properties of pectin film. Adding a plasticizer could build up the higher mechanical characteristics of composite film. Stability of pectin could be modified by fabrication of composite films with proper content of shellac and plasticizer. © 2017 Institute of Food Technologists®.

Ultrasound determination of rotator cuff tear repairability

Science.gov (United States)

Tse, Andrew K; Lam, Patrick H; Walton, Judie R; Hackett, Lisa

2015-01-01

Background Rotator cuff repair aims to reattach the torn tendon to the greater tuberosity footprint with suture anchors. The present study aimed to assess the diagnostic accuracy of ultrasound in predicting rotator cuff tear repairability and to assess which sonographic and pre-operative features are strongest in predicting repairability. Methods The study was a retrospective analysis of measurements made prospectively in a cohort of 373 patients who had ultrasounds of their shoulder and underwent rotator cuff repair. Measurements of rotator cuff tear size and muscle atrophy were made pre-operatively by ultrasound to enable prediction of rotator cuff repairability. Tears were classified following ultrasound as repairable or irreparable, and were correlated with intra-operative repairability. Results Ultrasound assessment of rotator cuff tear repairability has a sensitivity of 86% (p tear size (p tear size ≥4 cm2 or anteroposterior tear length ≥25 mm indicated an irreparable rotator cuff tear. Conclusions Ultrasound assessment is accurate in predicting rotator cuff tear repairability. Tear size or anteroposterior tear length and age were the best predictors of repairability. PMID:27582996

Iatrogenic tracheal tear.

LENUS (Irish Health Repository)

Dias, A

2010-10-01

Large post intubation tracheal tears are usually detected intra-operatively due to unstable signs namely impaired ventilation and mediastinal emphysema and often require surgical management. Smaller tracheal tears are often missed during anaesthesia and recognized during the postoperative period. Conservative management should be considered in these latter cases.

Resistive wall tearing mode generated finite net electromagnetic torque in a static plasma

International Nuclear Information System (INIS)

Hao, G. Z.; Wang, A. K.; Xu, M.; Qu, H. P.; Peng, X. D.; Wang, Z. H.; Xu, J. Q.; Qiu, X. M.; Liu, Y. Q.

2014-01-01

The MARS-F code [Y. Q. Liu et al., Phys. Plasmas 7, 3681 (2000)] is applied to numerically investigate the effect of the plasma pressure on the tearing mode stability as well as the tearing mode-induced electromagnetic torque, in the presence of a resistive wall. The tearing mode with a complex eigenvalue, resulted from the favorable averaged curvature effect [A. H. Glasser et al., Phys. Fluids 18, 875 (1975)], leads to a re-distribution of the electromagnetic torque with multiple peaking in the immediate vicinity of the resistive layer. The multiple peaking is often caused by the sound wave resonances. In the presence of a resistive wall surrounding the plasma, a rotating tearing mode can generate a finite net electromagnetic torque acting on the static plasma column. Meanwhile, an equal but opposite torque is generated in the resistive wall, thus conserving the total momentum of the whole plasma-wall system. The direction of the net torque on the plasma is always opposite to the real frequency of the mode, agreeing with the analytic result by Pustovitov [Nucl. Fusion 47, 1583 (2007)]. When the wall time is close to the oscillating time of the tearing mode, the finite net torque reaches its maximum. Without wall or with an ideal wall, no net torque on the static plasma is generated by the tearing mode. However, re-distribution of the torque density in the resistive layer still occurs

Analysis of Factors Associated With the Tear Film Lipid Layer Thickness in Normal Eyes and Patients With Dry Eye Syndrome.

Science.gov (United States)

Jung, Ji Won; Park, Si Yoon; Kim, Jin Sun; Kim, Eung Kweon; Seo, Kyoung Yul; Kim, Tae-Im

2016-08-01

To determine the effects of clinical variables, including age, sex, history of refractive or cataract surgery, contact lens use, and ocular surface and meibomian gland parameters on the lipid layer thickness (LLT) in normal subjects and patients with dry eye syndrome (DES). A total of 64 normal subjects and 326 patients with DES were enrolled, and they underwent measurements of LLT with a LipiView interferometer and tear meniscus height using optical coherence tomography, tear film break-up time (TBUT) determination, ocular surface staining, Schirmer's test, examination of the lid margins and meibomian glands, and assessment using the Ocular Surface Disease Index (OSDI). In normal subjects, the median (range) LLT was 67 (33-100) nm, and age was the only factor that was significantly associated with LLT (β = 0.678, P = 0.028). In patients with DES, the median (range) LLT was 84 (20-100) nm, and 79.0% of the participants fulfilled the diagnostic criteria for meibomian gland dysfunction (MGD). In a multivariate analysis, increased age and female sex were significantly related to increased LLT (β = 0.282, P = 0.005 and β = 11.493, P < 0.001), and hypersecretory MGD and lid margin inflammation were independently associated with increased LLT (β = 11.299, P = 0.001 and β = 12.747, P = 0.001). Lipid layer thickness measurements using a new interferometer are significantly affected by demographic factors such as age, sex, ocular surgical history, and MGD type. Therefore, all of these factors must be considered in the diagnosis of ocular surface diseases.

Not all sagittal band tears come with extensor instability. A case report with radiological and operative correlation

International Nuclear Information System (INIS)

Li, Shuo; Jacob, Jubin; Ghasemiesfe, Ahmadreza; Marrinan, Greg B.; Brooks, Jeffrey J.

2018-01-01

The sagittal bands are a component of the extensor hood. They serve an important role in stabilizing the extensor tendon by forming a ''check-rein'' to radial-ulnar translation of the tendon over the metacarpal head, and extending the metacarpophalangeal (MCP) joint by virtue of attaching the extensor tendon to the palmar plate. Injury to the sagittal band is thought to cause extensor instability and subluxation to the contralateral side by disruption of this ''check-rein'' function, although recent evidence from cadaver studies suggests that ulnar sagittal band tear may be spared of extensor instability. As a case in point, we encountered a patient with surgically proven ulnar sagittal band tear, who did not have any extensor tendon subluxation or any limitation in motion. Intraoperative findings demonstrated a chronic-appearing ulnar sagittal band tear, indicating that chronic injury with fibrosis may stabilize the central band. Therefore, in patients with metacarpophalangeal pain without central tendon subluxation or limitation of motion, it remains important to raise the concern of sagittal band tear for appropriate treatment. We present the clinical course of this case, with radiological and operative findings, followed by a review of the relevant literature. (orig.)

Not all sagittal band tears come with extensor instability. A case report with radiological and operative correlation

Energy Technology Data Exchange (ETDEWEB)

Li, Shuo; Jacob, Jubin; Ghasemiesfe, Ahmadreza; Marrinan, Greg B. [Yale New Haven Health Bridgeport Hospital, Bridgeport, CT (United States); Brooks, Jeffrey J. [Orthopedic Surgery and Sports Medicine Center, New Canaan, CT (United States)

2018-04-15

The sagittal bands are a component of the extensor hood. They serve an important role in stabilizing the extensor tendon by forming a ''check-rein'' to radial-ulnar translation of the tendon over the metacarpal head, and extending the metacarpophalangeal (MCP) joint by virtue of attaching the extensor tendon to the palmar plate. Injury to the sagittal band is thought to cause extensor instability and subluxation to the contralateral side by disruption of this ''check-rein'' function, although recent evidence from cadaver studies suggests that ulnar sagittal band tear may be spared of extensor instability. As a case in point, we encountered a patient with surgically proven ulnar sagittal band tear, who did not have any extensor tendon subluxation or any limitation in motion. Intraoperative findings demonstrated a chronic-appearing ulnar sagittal band tear, indicating that chronic injury with fibrosis may stabilize the central band. Therefore, in patients with metacarpophalangeal pain without central tendon subluxation or limitation of motion, it remains important to raise the concern of sagittal band tear for appropriate treatment. We present the clinical course of this case, with radiological and operative findings, followed by a review of the relevant literature. (orig.)

Hot tearing studies in AA5182

Science.gov (United States)

van Haaften, W. M.; Kool, W. H.; Katgerman, L.

2002-10-01

One of the major problems during direct chill (DC) casting is hot tearing. These tears initiate during solidification of the alloy and may run through the entire ingot. To study the hot tearing mechanism, tensile tests were carried out in semisolid state and at low strain rates, and crack propagation was studied in situ by scanning electron microscopy (SEM). These experimentally induced cracks were compared with hot tears developed in an AA5182 ingot during a casting trial in an industrial research facility. Similarities in the microstructure of the tensile test specimens and the hot tears indicate that hot tearing can be simulated by performing tensile tests at semisolid temperatures. The experimental data were compared with existing hot tearing models and it was concluded that the latter are restricted to relatively high liquid fractions because they do not take into account the existence of solid bridges in the crack.

Classification and localization of acetabular labral tears

International Nuclear Information System (INIS)

Blankenbaker, D.G.; De Smet, A.A.; Keene, J.S.; Fine, J.P.

2007-01-01

The purpose of this study was to compare the findings on hip MR arthrography (MRA) with the published MRA and arthroscopic classifications of hip labral tears and to evaluate a clock-face method for localizing hip labral tears. We retrospectively reviewed 65 hip MRA studies with correlative hip arthroscopies. Each labrum was evaluated on MRA using the classification system of Czerny and an MRA modification of the Lage arthroscopic classification. In addition, each tear was localized on MRA by using a clock-face description where 6 o'clock was the transverse ligament and 3 o'clock was anterior. These MRA findings were then correlated with the arthroscopic findings using the clock-face method of localization and the Lage arthroscopic classification of labral tears. At MRA, there were 42 Czerny grade 2 and 23 grade 3 labral tears and 22 MRA Lage type 1, 11 type 2, 22 type 3 and 10 type 4 tears. At arthroscopy, there were 10 Lage type 1 flap tears, 20 Lage type 2 fibrillated tears, 18 Lage type 3 longitudinal peripheral tears and 17 Lage type 4 unstable tears. The Czerny MRA classification and the modified MRA Lage classification had borderline correlation with the arthroscopic Lage classification. Localization of the tears using a clock-face description was within 1 o'clock of the arthroscopic localization of the tears in 85% of the patients. The Lage classification, which is the only published arthroscopic classification system for hip labral tears, does not correlate well with the Czerny MRA or an MRA modification of the Lage classification. Using a clock-face description to localize tears provides a way to accurately localize a labral tear and define its extent. (orig.)

Stabilization of polar Mn3O4(001) film on Ag(001): Interplay between kinetic and structural stability

Science.gov (United States)

Kundu, Asish K.; Barman, Sukanta; Menon, Krishnakumar S. R.

2017-10-01

Stabilization processes of polar surfaces are often very complex and interesting. Understanding of these processes is crucial as it ultimately determines the properties of the film. Here, by the combined study of Low Energy Electron Diffraction (LEED), X-ray Photoelectron Spectroscopy (XPS) and Ultraviolet Photoemission Spectroscopy (UPS) techniques we show that, although there can be many processes involved in the stabilization of the polar surfaces, in case of Mn3O4(001)/Ag(001), it goes through different reconstructions of the Mn2O4 terminated surface which is in good agreements with the theoretical predictions. The complex surface phase diagram has been probed by LEED as a function of film thickness, oxygen partial pressure and substrate temperature during growth, while their chemical compositions have been probed by XPS. Below a critical film thickness of ∼ 1 unit cell height (8 sublayers or 3 ML) of Mn3O4 and oxygen partial pressure range of 2 × 10-8 mbar oxygen partial pressure (> 5 × 10-7 mbar) and higher temperature UHV annealing. The origin of these stripes has been explained with the help of UPS results.

Finite toroidal flow generated by unstable tearing mode in a toroidal plasma

Energy Technology Data Exchange (ETDEWEB)

Hao, G. Z., E-mail: haogz@swip.ac.cn; Wang, A. K.; Xu, Y. H.; He, H. D.; Xu, M.; Qu, H. P.; Peng, X. D.; Xu, J. Q.; Qiu, X. M. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Liu, Y. Q. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Sun, Y. [Institute of Plasma Physics, Chinese Academic of Sciences, P.O. Box 1126, Hefei 230031 (China); Cui, S. Y. [School of Mathematics and Statistics Science, Ludong University, Yantai 264025 (China)

2014-12-15

The neoclassical toroidal plasma viscosity torque and electromagnetic torque, generated by tearing mode (TM) in a toroidal plasma, are numerically investigated using the MARS-Q code [Liu et al., Phys. Plasmas 20, 042503 (2013)]. It is found that an initially unstable tearing mode can intrinsically drive a toroidal plasma flow resulting in a steady state solution, in the absence of the external momentum input and external magnetic field perturbation. The saturated flow is in the order of 0.5%ω{sub A} at the q=2 rational surface in the considered case, with q and ω{sub A} being the safety factor and the Alfven frequency at the magnetic axis, respectively. The generation of the toroidal flow is robust, being insensitive to the given amplitude of the perturbation at initial state. On the other hand, the flow amplitude increases with increasing the plasma resistivity. Furthermore, the initially unstable tearing mode is fully stabilized by non-linear interaction with the self-generated toroidal flow.

Stability of amorphous Ge-As(Sb)-Se films to high-energy electron irradiation

International Nuclear Information System (INIS)

Savchenko, N.D.

1999-01-01

The results of the investigation of high-energy electron (6.5 MeV) irradiation effect on structure, optical, electrical and mechanical properties for thin films obtained by thermal evaporation of Ge-As-Se and Ge-Sb-Se glasses have been presented. The electron-induced changes in film properties versus average coordination number and relative free volume for bulk glasses have been discussed. It has been found that the higher radiation stability is characteristic to the films deposited from the glasses with the lower relative free volume

Tearing mode saturation with finite pressure

International Nuclear Information System (INIS)

Lee, J.K.

1988-01-01

With finite pressure, the saturation of the current-driven tearing mode is obtained in three-dimensional nonlinear resistive magnetohydrodynamic simulations for Tokamak plasmas. To effectively focus on the tearing modes, the perturbed pressure effects are excluded while the finite equilibrium pressure effects are retained. With this model, the linear growth rates of the tearing modes are found to be very insensitive to the equilibrium pressure increase. The nonlinear aspects of the tearing modes, however, are found to be very sensitive to the pressure increase in that the saturation level of the nonlinear harmonics of the tearing modes increases monotonically with the pressure rise. The increased level is associated with enhanced tearing island sizes or increased stochastic magnetic field region. (author)

The Impact of Visual Guided Order Picking on Ocular Comfort, Ocular Surface and Tear Function.

Directory of Open Access Journals (Sweden)

Angelika Klein-Theyer

Full Text Available We investigated the effects of a visual picking system on ocular comfort, the ocular surface and tear function compared to those of a voice guided picking solution.Prospective, observational, cohort study.Institutional.A total of 25 young asymptomatic volunteers performed commissioning over 10 hours on two consecutive days.The operators were guided in the picking process by two different picking solutions, either visually or by voice while their subjective symptoms and ocular surface and tear function parameters were recorded.The visual analogue scale (VAS values, according to subjective dry eye symptoms, in the visual condition were significantly higher at the end of the commissioning than the baseline measurements. In the voice condition, the VAS values remained stable during the commissioning. The tear break-up time (BUT values declined significantly in the visual condition (pre-task: 16.6 sec and post-task: 9.6 sec in the right eyes, that were exposed to the displays, the left eyes in the visual condition showed only a minor decline, whereas the BUT values in the voice condition remained constant (right eyes or even increased (left eyes over the time. No significant differences in the tear meniscus height values before and after the commissioning were observed in either condition.In our study, the use of visually guided picking solutions was correlated with post-task subjective symptoms and tear film instability.

Percentage Level of Tannin fur Rabbit for Leather Concerning Stitch Tearing Strength, Tearing Strength and Flexibility

OpenAIRE

Mustakim Mustakim; Aris Sri Widati; Lisa Purnaningtyas

2012-01-01

The purpose of this study was to find out the appropriate of tannin level for rabbit fur leather concerning stitch tearing strength, tearing strength, and flexibility. The result were expected to contribute good information for the society, leather craftsman, and further researchers about fur leather tanning especially rabbit fur leather with tannin concerning stitch tearing strength, tearing strength and flexibility. The material that used were 12 pieces of four months of rabbit skin. The re...

Interaction of tearing modes

International Nuclear Information System (INIS)

Satya, Y.; Schmidt, G.

1979-01-01

A fully developed tearing mode modifies the magnetic field profile. The effect of this profile modification on the linear growth rate of a different tearing mode in a slab and cylindrical geometry is investigated

MRI diagnosis of meniscal tears

International Nuclear Information System (INIS)

Kuga, Naoyuki; Oh, Toshihiro

1996-01-01

We studied the accuracy of magnetic resonance imaging (MRI) of the knee in fifty-six patients who were also examined arthroscopically. The accuracy, sensitivity, and specificity were 96%, 100%, and 95% for medial meniscal tears, and 91%, 67%, and 100% for lateral meniscal tears respectively. Two MRIs of the medial meniscus were false-positives. These MRI findings were both meniscocapsular separation of the medial meniscus, but the arthroscopic findings were normal. One case was an ACL injury and the other PCL and MCL injury. Hemorrhage and edema of the medial capsule caused by valgus stress at injury may look like a meniscal pseudo-tear on MRI. Five MRIs of the lateral meniscus were false-negatives. All menisci showed normal signal and shape on MRI but traumatic and stable tears of the lateral meniscus were identified arthroscopically. All were associated with ACL tears and lateral condylar bone bruise. The traumatic and stable tear of the meniscus tended to be overlooked on MRI because a meniscus without degeneration shows a normal signal. (author)

Tear trough – Anatomy and treatment by autologous fat grafting

Directory of Open Access Journals (Sweden)

Chang Yung Chia

2016-07-01

Full Text Available Tear trough is the main irregularity at midface, of which treatment is difficult. There is no agreement in literature about its anatomy and best treatment. The author presented an anatomical study and personal autologous fat grafting technique for tear trough treatment. Anatomical dissections were done on two fresh cadavers to examine the skin, subcutaneous, muscle and bone layers, spaces, and attachments. Safety and efficacy were evaluated via retrospective analysis of the last 200 consecutive procedures performed by the author. Tear trough is caused by the abrupt transition of the palpebral orbicular oculi muscle (OOM (i.e., thin skin without subcutaneous fat compartment to the orbital OOM (i.e., thicker skin with malar fat compartment. The tear trough region is located at the OOM bony origin at the medial canthus where no specific ligament was found. The grafted fat volume stabilized at two or three months after the procedure, instead of six months as stated in literature, with excellent results and no severe complications. Tear trough is a personal characteristic, a natural anatomical depression caused by subcutaneous irregularity and can worsen with age. The lack of volume is not effectively corrected by surgeries and thus it must be filled. Fat grafting has several advantages over alloplastic fillers, although it may be more difficult. Fat graft is autologous and abundant, and tissue transplantation could enhance skin quality. Fat grafting is a simple, safe, and effective solution for adding extra volume to correct the deflation phenomenon of the midface aging process. There is no specific anatomical plane for volume injection; the fat graft must be evenly distributed in the deep and superficial plane for uniformity.

Stability of Tl-Ba-Ca-Cu-O superconducting thin films

International Nuclear Information System (INIS)

Siegal, M. P.; Overmyer, D. L.; Venturini, E. L.; Padilla, R. R.; Provencio, P. N.

1999-01-01

We report the stability of TlBa 2 CaCu 2 O 7 and Tl 2 Ba 2 CaCu 2 O 8 on LaAlO 3 (100) epitaxial thin films, under a variety of conditions. All films are stable in acetone and methanol and with repeated thermal cycling to cryogenic temperatures. Moisture, especially vapor, degrades film quality rapidly. These materials are stable to high temperatures in either N 2 or O 2 ambients. While total degradation, resulting from Tl depletion, occurs at the same temperatures for both phases, 600 degree sign C in N 2 and 700 degree sign C in O 2 , the onset of degradation occurs at somewhat lower temperatures for TlBa 2 CaCu 2 O 7 than for Tl 2 Ba 2 CaCu 2 O 8 . (c) 1999 Materials Research Society

Conjunctival impression cytology versus routine tear function tests for dry eye evaluation in contact lens wearers.

Science.gov (United States)

Kumar, Prachi; Bhargava, Rahul; Arora, Yogesh C; Kaushal, Sidharth; Kumar, Manjushri

2015-01-01

Prolonged contact lens wear is often accompanied by dryness of the eyes. The aim of this study was to compare conjunctival impression cytology (CIC) and tear film tests such as tear film break up time (TBUT) and Schirmer test for dry eye evaluation in contact lens wearers and measure their correlation with dry eye symptoms. A case control study was done at three referral eye centers. The eyes of 230 contact lens users were compared to 250 eyes of age- and sex-matched controls. Participants were recruited based on their response to a questionnaire of dry eye symptoms, (Dry Eye Scoring System, DESS(©)) and measurements of TBUT, Schirmer test, and CIC was done. A correlation analysis between symptom severity and tear film tests was performed. Pearson's coefficient, R(2) > 0.5 was considered significant. As compared to controls (r (2) = 0.010), Nelson grade correlated significantly with dry eye symptoms (r (2) = 0.765), among cases. However, there was moderate correlation between dry eye symptoms, Schirmer test, and TBUT (r (2) = 0.557 and 0.530, respectively) among cases and a weak correlation among controls (r (2) = 0.130 and 0.054, respectively). The sensitivity of TBUT was 86.4%, specificity was 82.4%, positive likelihood ratio (LR) was 4.50 [95% confidence interval (CI) 3.46-5.85)], and negative LR was 0.09. The sensitivity of the Schirmer test was 48.2%, specificity 88%, LR 2.12 (95% CI 1.48-2.96), and negative LR 0.83. CIC correlates better than Schirmer and TBUT with dry eye symptoms. It may be the most appropriate test for dry-eye evaluation in contact lens wearers.

Improved thermal stability of polylactic acid (PLA) composite film via PLA-β-cyclodextrin-inclusion complex systems.

Science.gov (United States)

Byun, Youngjae; Rodriguez, Katia; Han, Jung H; Kim, Young Teck

2015-11-01

The effects of the incorporation of PLA-β-cyclodextrin-inclusion complex (IC) and β-cyclodextrin (β-CD) on biopolyester PLA films were investigated. Thermal stability, surface morphology, barrier, and mechanical properties of the films were measured at varying IC (1, 3, 5, and 7%) and β-CD (1 and 5%) concentrations. The PLA-IC-composite films (IC-PLA-CFs) showed uniform morphological structure, while samples containing β-CD (β-CD-PLA-CFs) showed high agglomeration of β-CD due to poor interfacial interaction between β-CD and PLA moieties. According to the thermal property analysis, the 5% IC-PLA-CFs showed 6.6 times lower dimensional changes (6.5%) at the temperature range of 20-80°C than that of pure PLA film (43.0%). The increase of IC or β-CD content in the PLA-composite films shifted the glass transition and crystallization temperature to higher temperature regions. The crystallinity of both composite films improved by increasing IC or β-CD content. Both composite films had higher oxygen and water vapor permeability as IC or β-CD content increased in comparison to pure PLA film. All the composite films had less flexibility and lower tensile strength than the pure PLA film. In conclusion, this study shows that the IC technique is valuable to improve the thermal expansion stability of PLA-based films. Published by Elsevier B.V.

Control system of neoclassical tearing modes in real time on HL-2A tokamak

Science.gov (United States)

Yan, Longwen; Ji, Xiaoquan; Song, Shaodong; Xia, Fan; Xu, Yuan; Ye, Jiruo; Jiang, Min; Chen, Wenjin; Sun, Tengfei; Liang, Shaoyong; Ling, Fei; Ma, Rui; Huang, Mei; Qu, Hongpeng; Song, Xianming; Yu, Deliang; Shi, Zhongbin; Liu, Yi; Yang, Qingwei; Xu, Min; Duan, Xuru; Liu, Yong

2017-11-01

The stability and performance of tokamak plasmas are routinely limited by various magneto-hydrodynamic instabilities, such as neoclassical tearing modes (NTMs). This paper presents a rather simple method to control the NTMs in real time (RT) on a tokamak, including the control principle of a feedback approach for RT suppression and stabilization for the NTMs. The control system combines Mirnov, electron cyclotron emission, and soft X-ray diagnostics used for determining the NTM positions. A methodology for fast detection of 2/1 or 3/2 NTM positions with 129 × 129 grid reconstruction is elucidated. The forty poloidal angles for steering the electron cyclotron resonance heating (ECRH)/electron cyclotron current drive launcher are used to establish the alignment of antenna mirrors with the center of the NTM and to ensure launcher emission intersecting with the rational surface of a magnetic island. Pilot experiments demonstrate the RT control capability to trace the conventional tearing modes (CTMs) in the HL-2A tokamak. The 2/1 CTMs have been suppressed or stabilized by the ECRH power deposition on site or with the steerable launcher.

Effect of Al doping on phase formation and thermal stability of iron nitride thin films

Energy Technology Data Exchange (ETDEWEB)

Tayal, Akhil [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201 303 (India); Gupta, Mukul, E-mail: mgupta@csr.res.in [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201 303 (India); Pandey, Nidhi [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201 303 (India); Gupta, Ajay [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 001 (India); Horisberger, Michael [Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Stahn, Jochen [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

2015-11-25

In the present work, we systematically studied the effect of Al doping on the phase formation of iron nitride (Fe–N) thin films. Fe–N thin films with different concentration of Al (Al = 0, 2, 3, 6, and 12 at.%) were deposited using dc magnetron sputtering by varying the nitrogen partial pressure between 0 and 100%. The structural and magnetic properties of the films were studied using x-ray diffraction and polarized neutron reflectivity. It was observed that at the lowest doping level (2 at.% of Al), nitrogen rich non-magnetic Fe–N phase gets formed at a lower nitrogen partial pressure as compared to the un-doped sample. Interestingly, we observed that as Al doping is increased beyond 3 at.%, nitrogen rich non-magnetic Fe–N phase appears at higher nitrogen partial pressure as compared to un-doped sample. The thermal stability of films were also investigated. Un-doped Fe–N films deposited at 10% nitrogen partial pressure possess poor thermal stability. Doping of Al at 2 at.% improves it marginally, whereas, for 3, 6 and 12 at.% Al doping, it shows significant improvement. The obtained results have been explained in terms of thermodynamics of Fe–N and Al–N. - Highlights: • Doping effects of Al on Fe–N phase formation is studied. • Phase formation shows a non-monotonic behavior with Al doping. • Low doping levels of Al enhance and high levels retard the nitridation process. • Al doping beyond 3 at.% improve thermal stability of Fe–N films.

Stability of magnetic modes in tokamaks; Stabilite des modes magnetiques dans les tokamaks

Energy Technology Data Exchange (ETDEWEB)

Zabiego, M

1994-06-01

A theoretical study is carried out concerning two experimental topics: stabilization, by a suprathermal population, of the mode ``m=1, n=1`` which induces the sawtooth effect (modelling the role of suprathermal particles in the stabilization); stability, in the non linear regime, of the magnetic islands involved in magnetic turbulence problems (micro-tearing) and in disruption phenomena (tearing), and the effects of diamagnetism, excitation threshold and saturation levels. 45 figs., 97 refs.

Collisional tearing in a field-reversed sheet pinch assuming nonparallel propagation

International Nuclear Information System (INIS)

Quest, K.B.; Coroniti, F.V.

1985-01-01

We examine the linear stability properties of the collisional tearing mode in a reversed-field sheet pinch assuming that the wave vector is not parallel to B, where B is the equilibrium magnetic field. We show that pressure balance in the direction of the equilibrium current requires a nonzero perturbed current component deltaJ/sub z/ that is driven toward tyhe center of the pinch. At the center of the pinch, deltaJ/sub z/ goes to zero, and momentum is balanced by coupling to the ion-acoustic mode. In order to achieve current closure, a large perturbed field-aligned current is generated that is strongly localized about the dissipative tearing layer. The relation of this work to the collisionless case is discussed

Thermal stability of amorphous carbon films grown by pulsed laser deposition

Science.gov (United States)

Friedmann, T. A.; McCarty, K. F.; Barbour, J. C.; Siegal, M. P.; Dibble, Dean C.

1996-03-01

The thermal stability in vacuum of amorphous tetrahedrally coordinated carbon (a-tC) films grown on Si has been assessed by in situ Raman spectroscopy. Films were grown in vacuum on room-temperature substrates using laser fluences of 12, 22, and 45 J/cm2 and in a background gas of either hydrogen or nitrogen using a laser fluence of 45 J/cm2. The films grown in vacuum at high fluence (≳20J/cm2) show little change in the a-tC Raman spectra with temperature up to 800 °C. Above this temperature the films convert to glassy carbon (nanocrystalline graphite). Samples grown in vacuum at lower fluence or in a background gas (H2 or N2) at high fluence are not nearly as stable. For all samples, the Raman signal from the Si substrate (observed through the a-tC film) decreases in intensity with annealing temperature indicating that the transparency of the a-tC films is decreasing with temperature. These changes in transparency begin at much lower temperatures (˜200 °C) than the changes in the a-tC Raman band shape and indicate that subtle changes are occurring in the a-tC films at lower temperatures.

Danish translation and validation of the International Skin Tear Advisory Panel Skin Tear Classification System

DEFF Research Database (Denmark)

Skiveren, J; Bermark, S; LeBlanc, K

2015-01-01

OBJECTIVE: The aim of this study was to translate, validate and establish reliability of the International Skin Tear Classification System in Danish. METHOD: Phase 1 of the project involved the translation of the International Skin Tear Advisory Panel (ISTAP) Skin Tear Classification System......) and social and health-care assistants (non-RN) from both primary health care and a Danish university hospital in Copenhagen. Thirty photographs, with equal representation of the three types of skin tears, were selected to test validity. The photographs chosen were those originally used for internal...... and external validation by the ISTAP group. The subjects were approached in their place of work and invited to participate in the study and to attend an educational session related to skin tears. RESULTS: The Danish translation of the ISTAP classification system was tested on 270 non-wound specialists...

Bi-fluid and neoclassical effect on a Double-Tearing mode in Tore Supra

Energy Technology Data Exchange (ETDEWEB)

Maget, Patrick, E-mail: patrick.maget@cea.fr; Garbet, Xavier; Février, Olivier; Ségui, Jean-Luc [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Lütjens, Hinrich; Luciani, Jean-François [Centre de Physique Théorique, Ecole Polytechnique, CNRS (France)

2014-06-15

Tearing modes associated to hollow current profiles are prone to grow in moderate performance plasmas and often constrain the realization of non-inductive discharges in the Tore Supra tokamak, where long pulse duration is performed using Lower Hybrid waves for providing most of the plasma current. The prediction of MHD boundaries in such scenarios is complicated by the importance of diamagnetic effects, combined with curvature stabilization, which determine the stability of these modes. We show that diamagnetic effects, as well as neoclassical forces, are playing a key role in the linear and nonlinear regimes of Double-Tearing Modes on q = 5/3 and q = 2 in these experimental conditions. Detailed comparison with experimental measurements, combined with a scaling in plasma resistivity, give constraints about the experimental equilibrium. Resistive-Interchange Modes destabilized by diamagnetic rotation could also play a role in degrading the energy confinement in the negative magnetic shear region.

Chemical cross-linked polyvinyl alcohol/cellulose nanocrystal composite films with high structural stability by spraying Fenton reagent as initiator.

Science.gov (United States)

Song, Meili; Yu, Houyong; Gu, Jiping; Ye, Shounuan; Zhou, Yuwei

2018-07-01

Cross-linked polyvinyl alcohol (PVA) composite films with high structural stability were prepared by free radical copolymerization between cellulose nanocrystal (CNC) and maleic anhydride (MAH) modified PVA through spraying Fenton free radical as initiator. The influence of chemical cross-linked and physical network structure on mechanical, thermal and water absorption properties of the composite films were investigated. Compared to PVA and PVA/CNC composite film, significant improvements in the mechanical, thermal and water uptake properties of the cross-linked composite film were found. The tensile strength of the cross-linked composite film was enhanced from 23.1MPa (neat PVA film) and 32.6MPa (PVA/CNC-10%) to 42.5MPa, and the maximum thermal degradation temperature was increased from 266.8°C and 281.2°C to 366.7°C (cross-linked composite film). Besides, the water absorption was reduced from 385.9% and 220.6% to 175.7% for cross-linked composite film. It indicates that compared with physical network structure in PVA/CNC composite film, the multiple cross-linked networks showed excellent thermal stability, resistance of water swelling and structural stability at the same CNC loading level. Thus, the PVA/CNC composite film with the multiple cross-linked network shows greater property reinforcements. Copyright © 2018 Elsevier B.V. All rights reserved.

Tearing modes induced by perpendicular electron cyclotron resonance heating in the KSTAR tokamak

Science.gov (United States)

Lee, H. H.; Lee, S. G.; Seol, J.; Aydemir, A. Y.; Bae, C.; Yoo, J. W.; Na, Y. S.; Kim, H. S.; Woo, M. H.; Kim, J.; Joung, M.; You, K. I.; Park, B. H.

2014-10-01

This paper reports on experimental evidence that shows perpendicular electron cyclotron resonance heating (ECRH) can trigger classical tearing modes when deposited near a rational flux surface. The complex evolution of an m = 2 island is followed during current ramp-up in KSTAR plasmas, from its initial onset as the rational surface enters the ECRH resonance layer to its eventual lock on the wall after the rational surface leaves the layer. Stability analysis coupled to a transport calculation of the current profile with ECRH shows that the perpendicular ECRH may play a significant role in triggering and destabilizing classical m = 2 tearing modes, in agreement with our experimental observation.

Arthroscopic repair of large U-shaped rotator cuff tears without margin convergence versus repair of crescent- or L-shaped tears.

Science.gov (United States)

Park, Jin-Young; Jung, Seok Won; Jeon, Seung-Hyub; Cho, Hyoung-Weon; Choi, Jin-Ho; Oh, Kyung-Soo

2014-01-01

For large-sized tears of the rotator cuff, data according to the tear shape have not yet been reported for repair methodology, configuration, and subsequent integrity. The retear rate after the repair of large mobile tears, such as crescent- or L-shaped tears, is believed to be lower compared with retear rates after the repair of large U-shaped tears that are accompanied by anterior or posterior leaves of the rotator cuff. Cohort study; Level of evidence, 3. Data were collected and analyzed from 95 consecutive patients with a large-sized rotator cuff tear who underwent arthroscopic suture-bridge repair. Patients were divided into 2 groups: those having crescent- or L-shaped tears (mobile tear group, 53 patients) and those having U-shaped tears (U-shaped tear group, 42 patients). The integrity of the repaired constructs was determined by ultrasonography at 4.5, 12, and 24 months. Moreover, clinical evaluations were performed by using the Constant score, the American Shoulder and Elbow Surgeons (ASES) score, and muscle strength at intervals of 3, 6, 12, and 24 months postoperatively. On ultrasonography at 4.5, 12, and 24 months, a retear was detected in 6, 2, and 1 patients in the mobile tear group and in 5, 2, and 1 patients in the U-shaped tear group, respectively. Significant differences in retear rates were not detected between the groups overall or at each time point. Moreover, clinical scores were similar between groups, except for the presence of a temporarily higher Constant score at 12 months in the mobile tear group. With regard to shoulder strength, between-group comparisons indicated no statistically significant difference, either in abduction or external rotation, except for the presence of temporarily higher external rotation strength at 3 months in the mobile tear group. Arthroscopic repair of large-sized rotator cuff tears yielded substantial improvements in shoulder function, regardless of tear retraction, during midterm follow-up. Moreover, the