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Littérature scientifique sur le sujet « Tear Break Up Time test »

Auteur : Grafiati

Publié le 9 mars 2023

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Articles de revues sur le sujet "Tear Break Up Time test"

Ahsan, Maria, Misbah Sattar, Asifa Saba, Asima saba, Sara sonum et Asma batool. « Evaluation of tear film instability pre and post corneal collagen cross-linking procedure in keratoconus patients ». Advances in Ophthalmology & ; Visual System 11, n^o 1 (14 juillet 2021) : 23–26. http://dx.doi.org/10.15406/aovs.2021.11.00403.

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Purpose: To evaluate tear film instability in keratoconus patients pre and post CXL procedure. Study design: Prospective cross-sectional study. Place and duration of study: Study was conducted at Al Ehsan Welfare eye hospital Lahore from 15th September, 2020 to 15th June, 2021. Materials and methods: Tear break-up time (TBUT) test was used for determining the stability of the tear film out of 30 patients diagnosed with mild, moderate and severe keratoconus and tear film stability was assessed before and after CXL procedure by measuring tear break up time. Data was collected by using non-probability convenient sampling method. The patients were excluded if they had any previous dry eye syndrome, tear film instability, refractive surgery, other ocular surface abnormalities, cataract surgery and contact lens use before the CXL procedure. Pre and post-operative tear break up time was measured by performing TUBT test. Patients were selected between the age 25 to 35 years. In TBUT, sodium fluorescein dye was used and the tear film was observed with slit lamp under low magnification while the patient was instructed to avoid blinking while time was calculated until first dry spot appearance. SPSS version 21 was used for data analysis and Mcneemar’s test (kappa statistics) was applied with significance of p <0.05. Results: Results shows that pre CXL tear breakup time of 22 patients was normal (10-15) sec while 8 patients were observed with borderline tear break up time less than 10 sec with percentage of 73.3% and 26.7 % respectively. Results of Post TBUT after one week of CXL procedure shows variation in values of tear break up time which shows decrease of tear break up time less than 10 sec of 12 patients and 18 patients with significantly reduced tear break up time less than 5 sec was recorded with percentage of 40.% and 60. % respectively. After two weeks of procedure it was recorded that tear break up time of 4 patients was normal (10-15 sec) post tear break up time, while tear break up time of 18 patients was noted borderline (<10 sec) and 8 patient with reduced post tear break up time (<5sec) with percentage of 13.3 % , 60 % and 26.7% respectively. After one month of CXL the tear break up time was significantly improved as compared to one and two weeks of postoperative procedure of CXL as the corneal epithelium was regenerated. Conclusion: This study concludes that tear breakup time was significantly reduced after CXL procedure. TBUT was normal before the CXL but after CXL due to destruction of corneal epithelium the TBUT was reduced. Thus results reveals instability of tear films occurs after CXL procedure.

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Acet, Yakup. « Topographic tear film trend and new parameters for non-invasive break up time test ». International Journal of Ophthalmology 15, n^o 12 (18 décembre 2022) : 1932–39. http://dx.doi.org/10.18240/ijo.2022.12.06.

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AIM: To evaluate the quantitative and qualitative results of the noninvasive tear film break-up time (NI-BUT) test and investigate the predictive ability of the new NI-BUT parameter in discriminating between normal Ocular Surface Disease Index (OSDI; scores ≤12) and abnormal OSDI (scores ≥13). METHODS: A total of 341 eyes of 341 volunteers who applied for routine eye outpatient control were included in the prospective study. All participants’ noninvasive first tear film break-up time (NIF-BUT), noninvasive average tear film break-up time (NIAvg-BUT) and average value of the first three break-up time (A3F-BUT) were analyzed. A3F-BUT, the new NI-BUT parameter, is calculated by adding the NIF-BUT value to the 2nd break-up time value that has a difference of at most 1 second from the NIF-BUT value and to the 3rd break-up time and then dividing the respective sum by 3. Receiver operating characteristic (ROC) curve and forward logistic regression analyses were performed to determine the parameter that had the best predictive ability between the OSDI groups. RESULTS: The NI-BUT values of 255 eyes of 255 volunteers included in the study were analyzed statistically. The mean NIF-BUT, NIAvg-BUT, and A3F-BUT values were calculated as 5.3±3.0, 8±3.1, and 5.8±3.0 seconds, respectively. All three parameters were found to be significantly lower in the abnormal OSDI group (P=0.014, 0.034, and 0.011, respectively). The area under the curve (AUC) of the A3F-BUT to predict abnormal OSDI was AUC=0.625 (0.529-0.720), P=0.011 and NIF-BUT was AUC=0.599 (0.502-0.696), P=0.043. The A3F-BUT parameter and NIF-BUT parameters were found to be significantly efficient in discriminating abnormal OSDI. CONCLUSION: The new parameter for the NI-BUT test has more predictive ability in the discrimination of OSDI groups.

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Wang, Jianhua, Jayachandra R. Palakuru et James V. Aquavella. « Correlations Among Upper and Lower Tear Menisci, Noninvasive Tear Break-up Time, and the Schirmer Test ». American Journal of Ophthalmology 145, n^o 5 (mai 2008) : 795–800. http://dx.doi.org/10.1016/j.ajo.2007.12.035.

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Lim, Christine C., et Cheryl L. Cullen. « Schirmer tear test values and tear film break-up times in cats with conjunctivitis ». Veterinary Ophthalmology 8, n^o 5 (septembre 2005) : 305–10. http://dx.doi.org/10.1111/j.1463-5224.2005.00403.x.

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Alanazi, Mana A., Gamal A. El-Hiti, Rashid Al-Tamimi, Abdullah M. Bawazir, Essam S. Almutleb, Raied Fagehi, Saud A. Alanazi et Ali M. Masmali. « Assessment of the Effect of Wearing a Surgical Face Mask on Tear Film in Normal Eye Subjects ». Journal of Ophthalmology 2022 (16 août 2022) : 1–6. http://dx.doi.org/10.1155/2022/2484997.

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Purpose. To assess the effect of wearing a face mask for a short time on the tear film parameters in normal eye subjects. Methods. Fifty-four normal eye subjects (14 female and 40 male) aged 18–40 years (23.8 ± 4.4 years) were recruited. A standardized patient evaluation of eye dryness was completed first, followed by noninvasive tear break-up time, phenol red thread, and tear ferning tests. A 5-minute gap was allowed between the tests. The subjects were asked to wear a surgical mask for one hour. The measurements were taken both before wearing a face mask and immediately after its removal. Results. Significant (Wilcoxon test) differences were found between the standardized patient evaluation of eye dryness ( p = 0.002 ) and the noninvasive tear break-up time scores ( p < 0.001 ) before and after wearing face masks. No significant differences (Wilcoxon test, p > 0.05 ) were found between the phenol red thread scores and tear ferning grades before and after wearing face masks. Strong correlations (Spearman’s rank correlation coefficient, r) were found among the standardized patient evaluation of eye dryness score (r = 0.590; p < 0.001 ), noninvasive tear break-up time measurements (r = 0.631; p < 0.001 ), and the tear ferning grades (r = 0.517; p < 0.001 ) before and after wearing the mask. A medium correlation (r = 0.377; p = 0.005 ) was found between the noninvasive tear break-up time scores and tear ferning grades before wearing the mask. Conclusions. Wearing a surgical face mask for a short duration of one hour has an effect on ocular tear film in normal eye subjects. Dry eye symptoms and tear break-up increased after wearing a face mask compared with those experienced before wearing one.

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Higgins, David, Kevin Webb, Stanley Shapleigh, David Huebner, Terry Carmolli et Brenda Hall. « RELATIONSHIP BETWEEN COMFORT AND TEAR BREAK-UP TIME USING THE AKORN DRY EYE TEST. » Cornea 19, Supplement 2 (novembre 2000) : S94. http://dx.doi.org/10.1097/00003226-200011002-00076.

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Narayanan, Srihari, William L. Miller, Julie Jackson, Stanley Woo, Norman Leach et Jan P. G. Bergmanson. « (CL-250)COMPARISON OF NONINVASIVE TEAR BREAK-UP TIME TO THE DRY EYE TEST ». Optometry and Vision Science 77, SUPPLEMENT (décembre 2000) : 182. http://dx.doi.org/10.1097/00006324-200012001-00302.

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CHO, PAULINE. « Reliability of a Portable Noninvasive Tear Break-Up Time Test on Hong Kong-Chinese ». Optometry and Vision Science 70, n^o 12 (décembre 1993) : 1049–54. http://dx.doi.org/10.1097/00006324-199312000-00010.

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Lawrence, Premsudhakar. « Signs and Symptoms of Dry Eye Among Silicone Hydrogel Soft Contact Lens Wearers ». Bioscience Biotechnology Research Communications 15, n^o 2 (25 juin 2022) : 288–94. http://dx.doi.org/10.21786/bbrc/15.2.4.

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Silicone Hydrogel Contact Lenses (SiH CL) provides better comfort when compared with hydrogel contact lenses. But the signs that show up in wearers with reduced comfort are unclear. Thus, we aimed to study the association between symptoms and clinical signs of dry eye in SiH CL wearers. Forty-eight SiH CL wearers (mean age: 28.8 ± 5.0 years) underwent ocular assessments with and without contact lens, and completed Contact Lens Dry Eye questionnaire-8 (CLDEQ-8). Contact-lens related dryness was reported by 52.1% (n=25) subjects. A significant (p<0.01) Spearman’s correlation was found between CLDEQ-8 score and pre-lens tear film non-invasive tear break-up time (r=-0.80), pre-ocular tear film non-invasive tear break-up time (r=-0.78), invasive tear break-up time (-0.87), and Schirmer test (r=-0.83). In conclusion, for comfortable SiH CL usage, a healthy tear film is essential, and a thorough clinical evaluation may be beneficial in alleviating discomfort.

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Vulovic, Tatjana Sarenac, Sladjana Pavlovic, Katarina Janicijevic, Dusan Todorovic, Mitar Lutovac, Svetlana Paunovic, Nenad Petrovic, Svetlana Jovanovic et Nemanja Zdravkovic. « Tear Film Stability in Patients with Pseudexfoliation ». Serbian Journal of Experimental and Clinical Research 19, n^o 3 (1 septembre 2018) : 243–46. http://dx.doi.org/10.1515/sjecr-2017-0002.

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Abstract Pseudoexfoliation syndrome is an age related disorder, characterized by abnormal fibrous fiber production and accumulation in different visceral organs as well as in the eye and periocular tissues. Hystological examination recorded the presence of the pseudoexfoliation in the conjunctiva, and they can disturb the accessory lacrimal gland and goblet cell function. This can explain tear film instability in patients with pseudoexfoliations. In our study, we examined the tear film stability in patients with and without pseudoexfoliation, using Schirmer test and tear break up time test. Our results indicated that patients with pseudoexfoliation had lower values of Schirmer and tear break up time tests than patients without it. Pseudoexfoliation is the main reason for the instability of the tear film, because of its negative impact on the conjucntival goblet cells. In conclusion, ophthalmologists must have these data on their mind in the process of the pseudoexfoliation glaucoma treatment and controlling.

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Thèses sur le sujet "Tear Break Up Time test"

Yeo, Chwee Hong Anna. « Anatomical correlation of tear instability in Chinese eyes ». Thesis, Queensland University of Technology, 2000. https://eprints.qut.edu.au/36753/1/36753_Yeo_2000.pdf.

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Mucin deficiency is a possible cause of tear film instability. The important sources of mucin are the conjunctival goblet cells and the non-goblet conjunctiva! epithelial cells where the mucin-like glycoproteins are stored in the mucous secretory vesicles. This thesis addresses the relationship between the quantity of the mucin sources and tear film physiology in a group of normal to marginal dry eye Chinese subjects. Chinese subjects were used in this study because they were found to have a lower tear break-up time than Caucasians (Cho and Brown, 1993). Impression cytology techniques were used to obtain conjunctiva! cells and goblet cells from the bulbar conjunctiva! of 61 subjects in order to study the relationship of the goblet cell density and tear film stability. The tear function tests included subjective dry eye symptoms, non-invasive tear break-up time, phenol red thread test and tear break-up time. A second source of mucin supply and tear film stability was also studied. This mucin supply comes from the mucous secretory vesicles of the conjunctival epithelial cells. To study the anatomical structure, the ultrastructure of the conjunctiva! epithelial cells was investigated under the transmission electron microscope. The findings revealed that goblet cell density did not show any correlation with severity of dry eye symptoms, non-invasive tear break-up time, phenol red thread test or tear break-up time test. There are three possibilities for this finding: Deficiency in goblet cell density is not associated with mucin deficiency but mucin de2. Mucin deficiency is not associated with low tear stability but deficiency in goblet cell density remains associated with mucin deficiency. 3. Deficiency in goblet cell density is not associated with mucin deficiency and mucin deficiency is not associated with low tear stability.ficiency remains associated with low tear stability. The negative finding could also be due to the relatively normal and healthy subjects used in the present study. They did not show a great reduction in goblet cell density that could cause an impact on the result. In the counting of goblet cell density using the impression cytology technique, the imprints of the goblet cells might be obtained instead of the whole goblet cells. There was also no significant correlation between dry eye symptoms and tear function tests such as the non-invasive tear break-up time, phenol red thread test and tear break-up time test. This study also found that the gender of the age group between 18 to 28, and contact lens wear of up to three years, would not affect goblet cell density, dry eye symptoms, non-invasive tear break-up time, phenol red thread test and tear break-up time. There was no significant difference in the number of mucous secretory vesicles, microvilli and cell invaginations in the conjunctiva} epithelial cells of subjects with high and low tear stabilities. Therefore, the tear film function may not be associated with the presence of the number of mucous vesicles, microvilli and cells invaginations. On the other hand, the finding could also be due to a small subject sample and the inter-group difference in tear stability might be too small to reflect a difference in the assessment of the ultrastructures. However, a new technique of cell processing for transmission electron microscopy work was also developed for specimens obtained using the impression cytology technique.

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FARCI, ROBERTA. « APPROCCIO INTEGRATO ALLO STUDIO DEL GLAUCOMA : DALLA CLINICA ALL'INDAGINE BIOCHIMICO-MOLECOLARE ». Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/869186.

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Il glaucoma è una patologia neurodegenerativa sostenuta dalla morte per apoptosi delle CGR. Rappresenta la principale causa di cecità irreversibile al mondo. Non sono ancora stati compresi a fondo tutti i meccanismi che causano la degenerazione neuronale nel glaucoma (tanto che sussistono delle forme di glaucoma a PIO normale). Un ruolo importante nel meccanismo patogenetico glaucomatoso viene riconosciuto oggi ad una condizione di infiammazione cronica a livello retinico determinata da alterazioni dei livelli di PIO. Lo scopo del presente progetto di dottorato è stato un approccio multidisciplinare al glaucoma, di tipo clinico e biochimico-molecolare. In primo luogo, è stato implementato un prototipo di perimetro (Compass, Centervue, Padova, Italia), attuando dapprima un database normativo di soggetti sani al fine di integrare le caratteristiche demografiche per il test perimetrico 30-2. Successivamente, è stata valutata l’affidabilità test-retest dell’apparecchio, eseguendo il campo visivo “New Grid” per sei volte consecutive in un gruppo di pazienti clusterizzati secondo l’MD, ottenendo una bassa variabilità intra-test. È stato altresì calcolato l’agreement tra tre diversi revisori, i quali hanno esaminato indipendentemente le perimetrie e le foto fundus Compass, stabilendo un peggioramento o meno della patologia glaucomatosa, nonché la concordanza tra l’analisi da remoto dei campi visivi e immagini Compass, e la visita clinica standard dei pazienti affetti da glaucoma. I risultati hanno messo in evidenza un’ottima concordanza tra i Reviewers e tra gli esami da remoto e la visita clinica. Ai fini di stabilire la precisione punto per punto del perimetro, è stata eseguita un’analisi del Compass 10-2 in pazienti affetti da atrofia geografica, trovando una corrispondenza punto per punto della perimetria con l’immagine retinica sottostante. In ultimo, è stata effettuata un’analisi dell’osmolarità lacrimale e di tutti i parametri clinici del film lacrimale in pazienti affetti da glaucoma asimmetrico. Per quanto riguarda l’indagine biochimico-molecolare, è stata effettuata una analisi preliminare nell’umore acqueo della proteina di gap-junction Connessina 43 in un piccolo gruppo di soggetti sani e glaucomatosi, che ha posto in evidenza un aumento quasi doppio della dell’espressione della molecola nei soggetti glaucomatosi, anche se la ridotta numerosità del campione non ha prodotto un risultato statisticamente significativo. È stato inoltre utilizzato in questo progetto di dottorato un metodo innovativo di analisi: la metabolomica, ramo scientifico che si occupa di analizzare i metaboliti <1,5 kDa che derivano da specifici processi chimici cellulari in campioni biologici umani. Utilizzando la Spettroscopia di Risonanza Magnetica Nucleare 1H, sono stati analizzati campioni di vitreo di pazienti sottoposti a vitrectomia, identificando un aumento di acetone e metanolo negli occhi glaucomatosi.
Glaucoma is a neurodegenerative disease caused by ganglion cells death by apoptosis. It represents the leading cause of irreversible blindness in the world. Although the mechanisms triggering the neuronal degeneration in glaucoma have not yet been fully understood, a chronic inflammatory condition at the retinal level, sustained by abnormal IOP, is considered today a main factor in glaucoma pathogenesis. The aim of this PhD project was a multidisciplinary approach to glaucoma investigation, both clinical and bio-molecular. Firstly, a prototype of visual field analyzer (Compass, Centervue, Padua, Italy) was implemented, primarily by developing a demographic database of healthy subjects for 30-2 perimetric test. Subsequently, the test-retest reliability of the device was assessed by performing the "New Grid" visual field six straight times in a group of patients clustered according to the MD, resulting in a good inter-test reliability. The agreement between three different reviewers was also calculated: they independently examined Compass visual fields and the fundus photos, establishing whether or not the glaucomatous pathology worsened, as well as the agreement between the remote analysis and the standard clinical visit of glaucoma patients. The results highlighted an excellent agreement among the Reviewers and between remote analysis and the clinical examination. In order to establish the Compass’ point-by-point accuracy, a 10-2 visual field was performed in patients affected by geographic atrophy, finding an accurate correspondence of the perimetric scores with the underlying retinal image. Ultimately, the osmometry and all the clinical parameters of the tear film were analyzed in patients suffering from asymmetric glaucoma. Afterwards, for the biochemical and molecular approach, the analysis of gap-junction protein connexin 43 in the aqueous humor of affected and unaffected glaucoma patients was performed: a nearly double expression of the protein was found in glaucomatous subjects, even if there were no statistically significant differences, probably due to the small number of samples. An innovative method of biochemical analysis was introduced in this doctorate thesis: the metabolomics, a scientific branch that deals with the analysis of <1.5 kDa metabolites deriving from specific cellular processes in human samples. Vitreous samples of patients operated by vitrectomy were analyzed by 1H-NMR Nuclear Magnetic Resonance Spectroscopy, and an increase in acetone and methanol was observed in glaucomatous eyes.

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Abdul, Rahim Muhammad Afzam Shah Bin. « An investigation of computer vision syndrome with smart devices ». Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/12813.

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The overarching theme of the thesis was to investigate the association between smart device use and computer vision syndrome. The initial study designed and developed the Open Field Tear film Analyser (OFTA) enabling a continuous, real-time assessment of the tear film and blink characteristics during smart device use. The monocular OFTA prototype was validated and showed good intra- and inter-observer repeatability relative to the Oculus Keratograph 5M and Bausch and Lomb one position keratometer. Subsequently, tear osmolarity following engagement with reading and gaming tasks on smart device and paper platforms was investigated. Discrete measures of osmolarity pre- and post-engagement with the tasks were obtained with the TearLab osmometer; osmolarity values differed between platforms when participants were engaged in a gaming task but no such difference was observed with the reading task. In addition, the influence of repeated measurements on tear osmolarity was also explored. To simulate the habitual binocular viewing conditions normally associated with smart device use, the binocular OFTA was developed. The device was used to assess the tear film and blink characteristics whilst engaging with reading and gaming tasks on smart device and paper platforms. The results revealed differences in blink characteristics and non-invasive tear break up time between the different platforms and tasks assessed. In addition, the thesis also reports on an investigation examining the real-time accommodative response to various targets displayed on smart devices using an open-field autorefractor with a Badal lens system adaptation. The results showed that accommodative latency, accommodative lag, mean velocity of accommodation, speed of disaccommodation and mean velocity of disaccommodation varied across the different platforms. Through the use of validated subjective questionnaires and smartphone apps, the relationship between duration of smartphone use and symptoms of dry eye were examined. The findings of this study demonstrated that longer duration of smartphone and personal computer use were associated with higher risk of dry eyes as indicated by subjective questionnaire outcomes.

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Khan, Naimah Ebrahim. « Schirmer tear test 2 and tear break-up time values in a South African young black adult population ». Thesis, 2012. http://hdl.handle.net/10413/10078.

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Aim: The aim of this study was to establish normal values for Schirmer tear test (version 2) and tear break up time (TBUT) in a South African young adult Black population. Method: Following ethical approval by the biomedical research and ethics committee, KwaZulu-Natal, participants were recruited from the city of Durban in South Africa via personal invitations, poster advertisements and University of KwaZulu-Natal optometry clinic clients. McMonnies questionnaire for dry eye diagnosis was administered and those who failed were excluded from the main study. Two hundred (100 males and 100 females) participants who met the inclusion criteria were included in the study. Following a slit lamp examination of the eye, the Schirmer test was administered and the following day, the TBUT was measured. A re-test version of the two procedures were conducted one week after, at about the same time of the day for each subject. Results: The participants were aged 18-30 years, mean = 20.77 ± 2.29 years. The mean Schirmer test values for all participants (N = 200; 400 eyes) was 15.96 ± 6.86mm. The values for the males and females (200 eyes each) were 16.34 ± 6.93mm and 15.58 ± 6.81mm respectively. The mean TBUT (400 eyes) was 7.18 ± 1.89 secs. The mean values for the males and females (200 eyes each) were 6.90 ± 1.88 secs and 7.32 ± 1.67 secs respectively. A strong positive correlation (r = 0.895) and (r = 0.914) respectively was found between the right and left eyes in the two tests. Conclusion: Generally, the mean values found in this study for the Schirmer test are similar to those that have been reported in the literature. However, values for TBUT differ from the values that have been previously reported, being higher in some instances and lower in others. These findings have implications for dry eye diagnosis and also contact lens practice in South Africa.
Thesis (M.Optom.)-University of KwaZulu-Natal, Westville, 2012.

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Livres sur le sujet "Tear Break Up Time test"

Ehrig, Stephan, Britta C. Jung et Gad Schaffer, dir. Exploring the Transnational Neighbourhood. Leuven University Press, 2022. http://dx.doi.org/10.11116/9789461664815.

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Urban neighbourhoods have come to occupy the public imagination as a litmus test of migration, with some areas hailed as multicultural success stories while others are framed as ghettos. In an attempt to break down this dichotomy, Exploring the Transnational Neighbourhood filters these debates through the lenses of geography, anthropology, and literary and cultural studies. By establishing the interdisciplinary concept of the 'transnational neighbourhood', it presents these localities – whether Clichy-sous-Bois, Belfast, El Segundo Barrio or Williamsburg – as densely packed contact zones where disparate cultures meet in often highly asymmetrical relations, producing a constantly shifting local and cultural knowledge about identity, belonging, and familiarity. Exploring the Transnational Neighbourhood offers a pivotal response to one of the key questions of our time: How do people create a sense of community within an exceedingly globalised context? By focusing on the neighbourhood as a central space of transcultural everyday experience within three different levels of discourse (i.e., the virtual, the physical local, and the transnational-global), the multidisciplinary contributions explore bottom-up practices of community-building alongside cultural, social, economic, and historical barriers.

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Chapitres de livres sur le sujet "Tear Break Up Time test"

Ramos, Lucía, Noelia Barreira, Antonio Mosquera, Manuel Currás, Hugo Pena-Verdeal, María Jesús Giráldez et Manuel G. Penedo. « Computational Approach for Measuring the Tear Film Break-Up Time in an Unsupervised Manner ». Dans Advanced Techniques for Knowledge Engineering and Innovative Applications, 254–67. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-42017-7_18.

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Abelson, Mark B., George W. Ousler, Lauren A. Nally, Donna Welch et Kathleen Krenzer. « Alternative Reference Values for Tear Film Break up Time in Normal and Dry Eye Populations ». Dans Advances in Experimental Medicine and Biology, 1121–25. Boston, MA : Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-0717-8_157.

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Ramos, L., N. Barreira, A. Mosquera, H. Pena-Verdeal et E. Yebra-Pimentel. « Break-Up Analysis of the Tear Film Based on Time, Location, Size and Shape of the Rupture Area ». Dans Lecture Notes in Computer Science, 695–702. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-39094-4_79.

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Wahyu, Tri. « Examination for Dry Eyes ». Dans Dry Eye [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98800.

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Dry eye disease (DED) is a multifactorial disease of tears and ocular surface that results in various symptoms with the potential damage to the ocular surface. It can range from mild to severe signs and symptoms and may affect patient’s quality of life. Various techniques and methods have been developed to evaluate DED for initial examination or regular follow up. The simple evaluations that can be performed in clinic include eyelid examination, tear break-up time, and ocular surface stainings; while the advanced ones may require certain devices or laboratory equipment. Careful and thorough examinations are important to guide the clinician to assess and evaluate dry eye.

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Lacey, James. « Adrianople’s Aftermath ». Dans Rome, 327—C18.P16. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780190937706.003.0019.

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Abstract The true consequence of the Battle of Adrianople was that it locked in place the separation that had arisen when Constantine’s sons decided to divide the Empire between them and then fought a series of civil wars to bring it back together. In the meantime, they had done little to assist each other against outside threats. It had, of course, been long understood that the Empire was too big to be entirely run by just one man. This realization had been the basis for the tetrarchy, but even the tetrarchy had a single senior emperor to rule the others. There were always centrifugal forces trying to break up the Empire or tear parts of it away. After Adrianople, the Empire was for all practical purposes permanently divided, although not in any manifestly political way, as there remained two Augusti who were communicating with each other. What changed was that only rarely would either half of the Empire be willing to help one another. And even when they were, the help was rarely of meaningful size or long maintained. When Gratian’s army marched to help Valens, it marked the last time an eastern or western Roman field army marched to the assistance of the other. When his army marched back west, it heralded a break that doomed the consolidated Empire, which had existed since the reign of Augustus.

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Hess, Earl J. « This Will Be a Hard Place to Take ». Dans Storming Vicksburg, 70–91. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469660172.003.0005.

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Ulysses S. Grant spent nearly two days evaluating the results of the May 19 attack in order to decide whether to try another assault or initiate siege operations. Meanwhile the Federals concentrated on consolidating their position outside Vicksburg on May 20-21, especially firming up their supply line by way of the Mississippi River. Realizing that the May 19 attack had not been a true test of whether the army could break into Vicksburg, Grant decided to try one more time. He issued orders on May 21 for a general attack the next day at 10 a.m. He was largely supported in this decision by William T. Sherman who thought it had a real chance of succeeding. Grant worried about the presence of Confederate General Joseph E. Johnston at Jackson, Mississippi, forty-five miles east of Vicksburg. He knew that Johnston was assembling troops to save Vicksburg and a quick entry into the city would neutralize that threat. Grant also thought his troops would be reluctant to begin a siege unless they had one more chance to attack. In this, however, he was mistaken, for many Federal soldiers received the news of the pending attack with dread.

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« CONDITIONS OF ODOR THRESHOLD DETERMINATION 2.1 Requirements for the test area Olfactonetric measurement should be undertaken in a roan or area which is kept free frcm odors. There should be an atmosphere of ccmfort and relaxation in the test chamber, which will encourage panel members to concentrate on the testing task and not to be distracted by external sti muli. The test should be carried out at roan temperature and normal humi dity. 2.2 General conditions for test procedure Odor measurements must be carried out with the help of a team leader, who instructs the panelists and operates the measuring equipment. Ccmnu-nication between the team leader and the panel has to be kept to an abso lute minimum. Because of fatigue, the duration of a test series as well as the time of the whole session should be limited. Breaks of at least the same duration as the proceeding test period should be provided. Germany France Nether United lands Kingdcm Panel leader yes yes yes yes duration of 15-30 min 20 min 15 min test series duration of breaks 15-30 min 20 min ? 5 min 30 min 2 test 2 hours time of a test 300 tests/ series of period day 20 tests Table 1 : General conditions 3. DETECTION METHODS 3.1 Presentation of odor stimulus 3.1.1 Method of limits The most used method for establishing an absolute threshold in en vironmental studies is the Method of Limits. In its classical form, the stimuli are presented in alternating ascending and descending series, starting at different points to avoid having the subject fall into a rou tine. During this procedure there is a chance that adaptation phenomena may develop. An effort to minimize these effects is for example to use only an ascending series of stimuli. The threshold value for each sepa rate test series is defined as a point in-between the last undetected and the first detected point in the stimulus continuum. A modification of the method of limits is the "up and down" method. A stimulus is presented : if the response is positive, the next lower sti mulus is presented, if it is negative, the next higher is presented and so on. The primary advantage is, that it automatically concentrates near the mean and a considerable number of observations can be saved. » Dans Odour Prevention and Control of Organic Sludge and Livestock Farming, 70. CRC Press, 1986. http://dx.doi.org/10.1201/9781482286311-24.

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Actes de conférences sur le sujet "Tear Break Up Time test"

Cebreiro, Elsa, Lucía Ramos, Antonio Mosquera, Noelia Barreira et Manuel F. G. Penedo. « Automation of the tear film break-up time test ». Dans the 4th International Symposium. New York, New York, USA : ACM Press, 2011. http://dx.doi.org/10.1145/2093698.2093821.

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Carpente, A., L. Ramos, N. Barreira, M. G. Penedo, H. Pena-Verdeal et M. J. Giraldez. « On the Automation of the Tear Film Non-invasive Break-up Test ». Dans 2014 IEEE 27th International Symposium on Computer-Based Medical Systems (CBMS). IEEE, 2014. http://dx.doi.org/10.1109/cbms.2014.54.

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Orlandi de Oliveira, Lucas, André Orlandi de Oliveira et Jarbas Caiado de Castro Neto. « Analysis of tear film break-up time based on the tear film surface quality obtained using Placido rings images ». Dans Ophthalmic Technologies XXX, sous la direction de Fabrice Manns, Per G. Söderberg et Arthur Ho. SPIE, 2020. http://dx.doi.org/10.1117/12.2544867.

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Amni Batrisyia Shamsul Amri, Nur, Mohammed Hazim Alkawaz, Kevin Loo Teow Aik et Md Gapar Md Johar. « An Overview of Dry Eye Analysis Algorithms for Tear Film Break-Up Time Detection ». Dans 2021 IEEE Symposium on Industrial Electronics & Applications (ISIEA). IEEE, 2021. http://dx.doi.org/10.1109/isiea51897.2021.9510004.

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Fidelix, Tania, Virginia Fernandes Moça Trevisani, Laura Santos, Denise Freitas, Luiz Antonio Vieira et Moacyr Rigueiro. « AB0508 SCHIRMER TEST, VAN BIJSTERVELD, OSS, AND BREAK-UP TIME TEST IN PRIMARY SJOGREN’S SYNDROME ». Dans Annual European Congress of Rheumatology, EULAR 2019, Madrid, 12–15 June 2019. BMJ Publishing Group Ltd and European League Against Rheumatism, 2019. http://dx.doi.org/10.1136/annrheumdis-2019-eular.7280.

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Xu, S., W. R. Tyson, C. H. M. Simha, M. Gesing et J. Liang. « CTOA Test Method Using Drop-Weight Tear Test (DWTT) : Background and Development of Standard ». Dans 2016 11th International Pipeline Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ipc2016-64058.

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Arrest of fast ductile fracture in the design of gas pipelines has traditionally been assured by specifying Charpy absorbed energy (Cv) of pipe steel based on the Battelle two-curve method. However, the Charpy test has been shown to be inadequate to characterize crack propagation in modern high-strength, high-toughness pipe steels. For steels with Cv more than approximately 100 J, fracture arrest methodologies based on Cv can lead to non-conservative predictions. The problem is that the Charpy specimen is too small to characterize full-scale fracture, and for tough steels the ductility can be so high that the Charpy specimen bends without fracturing completely. To overcome these limitations, the use of a larger full-thickness specimen, the “Drop-Weight Tear Test” (DWTT) specimen, has been proposed. The test is instrumented to measure the force on and displacement of the impactor during crack propagation. The data is interpreted to yield the “crack-tip opening angle” (CTOA), which is constant during steady-state crack growth and characterizes the propagation resistance. The CTOA has been proposed for some time as a suitable property to assess fracture propagation and arrest in high-pressure gas pipelines, but up to now a standard test method for measurement of the CTOA has not been available. To remedy this situation, a draft standard has been developed by the authors and is being balloted by ASTM E081. In this paper, the CTOA parameter and CTOA-based fracture arrest methodology will be introduced briefly. The background and development of the draft ASTM standard test method for determination of CTOA using the drop-weight tear test (DWTT) specimen will be reviewed including the procedure and the results of an international round robin. In the CTOA test method, the only adjustable parameter is the rotation factor (rp). Using a modified Xue-Wierzbicki damage mechanics model and a statistical analysis, rp has been determined to be a weak function of yield strength, Charpy absorbed energy and specimen thickness. Although no physical model has been developed to explain the interplay of these factors, they are all related to the extent and distribution of plastic deformation ahead of the crack. The technical background and quantification of rp will be described in this paper. It is intended to apply the CTOA test method to a broad range of steels, including thin (less than 6 mm) and thick (larger than 20 mm) pipe steels.

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Gallardo, S., A. Querol et G. Verdú. « Break Size Effects on CET Response in an Upper Head SBLOCA Transient ». Dans 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-54843.

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In the transients produced during Small Break Loss-Of-Coolant Accidents (SBLOCA), the maximum Peak Cladding Temperature (PCT) in the core could suffer rapid excursions which might strongly affect the core integrity. Most Pressurized Water Reactors (PWR) have Core Exit Thermocouples (CETs) to detect core overheating by considering that superheated steam flows in the upward direction when core uncovery occurs during SBLOCAs. Operators may start Accident Management (AM) actions to mitigate such accident conditions when the CET temperature exceeds a certain value. However, in a Vessel Upper Head SBLOCA, a significant delay in time and temperature rise of CETs from core heat-up can be produced. This work is developed in the frame of OECD/NEA ROSA Project Test 6-1 (SB-PV-9 in JAEA) handled in the Large Scale Test Facility (LSTF) of the Japan Atomic Energy Agency (JAEA). Test 6-1 simulated a PWR pressure vessel Upper-Head SBLOCA with a break size equivalent to 1.9% of the cold leg break under the assumption of total failure of High Pressure Injection System (HPIS). The paper shows several analyses about the geometry variables (size, location, flow paths and Upper Head nodalization) which can influence on the pressure vessel Upper Head SBLOCA model performed using the thermal-hydraulic code TRACE5.

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Suzuki, Mitsuhiro, Takeshi Takeda et Hideo Nakamura. « Performance of Core Exit Thermocouple for PWR Accident Management Action in Vessel Top Break LOCA Simulation Experiment at OECD/NEA ROSA Project ». Dans 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48754.

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Presented are experiment results of the Large Scale Test Facility (LSTF) conducted at the Japan Atomic Energy Agency (JAEA) with a focus on core exit thermocouple (CET) performance to detect core overheat during a vessel top break loss-of-coolant accident (LOCA) simulation experiment. The CET temperatures are used to start accident management (AM) action to quickly depressurize steam generator (SG) secondary sides in case of core temperature excursion. Test 6-1 is the first test of the OECD/NEA ROSA Project started in 2005, simulating withdraw of a control rod drive mechanism penetration nozzle at the vessel top head. The break size is equivalent to 1.9% cold leg break. The AM action was initiated when CET temperature rose up to 623K. There was no reflux water fallback onto the CETs during the core heat-up period. The core overheat, however, was detected with a time delay of about 230s. In addition, a large temperature discrepancy was observed between the CETs and the hottest core region. This paper clarifies the reasons of time delay and temperature discrepancy between the CETs and heated core during boil-off including three-dimensional steam flows in the core and core exit. The paper discusses applicability of the LSTF CET performance to pressurized water reactor (PWR) conditions and a possibility of alternative indicators for earlier AM action than in Test 6-1 is studied by using symptom-based plant parameters such as a reactor vessel water level detection.

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Picchi, A., A. Andreini, R. Becchi et B. Facchini. « A New Test Facility for Investigating Thermal Behaviour of Effusion Cooling Test Plates for RQL Combustors ». Dans ASME Turbo Expo 2020 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16151.

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Abstract In aero engines the combustors are subjected to critical thermal conditions in terms of high temperatures and corrosive environment, which could affect the service life of the entire system. As well known, Thermal Barrier Coatings (TBC) and above all cooling systems represents the state-of-the-art in the nowadays protecting methods: the maximization of this beneficial effect is achieved by defining an optimal cooling arrangement and developing suitable manufacturing technologies for these systems. In modern aero-engine combustors, one of the most effective cooling scheme for liners is composed by an effusion perforation coupled with a slot system to start the film cooling. The cooling performances are deeply influenced by the mutual interactions between swirling and cooling flows. In addition, for typical Rich-Quench-Lean (RQL) combustor architectures, the injection of air provided to promoting the local break-down of the flame mixture fraction, deeply interacts with the swirled flow, generating recirculating structures capable of affecting the development of film cooling and making the design of cooling systems very challenging. A new test facility for testing effusion test plates for RQL combustors applications has been developed with the final aim of comparing different cooling strategies and at the same time to collect data for numerical model validation. The experimental set-up consists of a non-reactive planar sector rigs with 5 engine-scale swirlers fed with air up to 250 °C and 3 bar. The rig was equipped with outer/inner dilution ports, and a simple inner liner cooling scheme composed of effusion and a slot system: all these features, fed with air at ambient temperature, can be independently controlled in terms of mass flow. Using dedicated optical accesses, InfraRed (IR) camera tests were performed to retrieve overall effectiveness data imposing a temperature difference between swirling and cooling flows. To better understand those results, Pressure Sensitive Paint (PSP) technique was used to obtain reliable film effectiveness data decoupling the contribution of slot and effusion flows. The thermal characterization was supported by Particle Image Velocimetry (PIV) investigations on the median plane. Tests were performed at different pressure drops across swirler and varying the mass flows of slot and inner/outer liners. The analysis of the data highlighted the influences of the swirling flow on the overall thermal performance and the behaviour of the film cooling system.

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Ryan, Matt, Yiwen Wang, Qinqin Xiao, Rui Liu et Yunbo Zhang. « Immersive Virtual Reality Training With Error Management for CNC Milling Set-Up ». Dans ASME 2022 17th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/msec2022-85770.

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Abstract In order to address the demand for skilled machinists and limitations with current training programs, we introduce an immersive Virtual Reality (VR) CNC machining training environment for CNC machine setup processes with a novel error management based training curriculum. Current machinist training programs are several years long requiring active mentorship from a skilled individual and are very costly due to the materials and tools required. Mistakes and errors made during the set up process can create safety risks, waste material and break equipment requiring additional time to reset. Existing VR CNC milling training environments fail to address mistakes that can occur during the setup process. In order to address these operational challenges, a novel error-management based training in VR is proposed which allows trainees to learn the set up procedure,learn the common errors & mistakes and practice identifying errors in addition to practicing activities for the setup. The training first introduces students to the setup procedure, followed by demonstrations of error cases and identification and management strategies culminating in practice opportunities. Trainees witness a spatial demonstration of the procedure, guided by auditory and text instructions. Users are able to actively explore the spatial teaching environment while controlling a virtual CNC milling machine. A preliminary user training test is performed comparing the VR method to a video training and a video training with error management curriculum.

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