Evaluation of Tear Evaporation Rate in Subjects with a High Body Mass Index.

AIM: This study evaluated the tear evaporation rate (TER) in subjects with a high body mass index (BMI) and tested the correlation between BMI and dry eye. METHODS: Thirty male subjects aged 18 - 38 years (26.4 ± 4.0 years) with a high BMI (26.4 - 47.0 kg/m2) were enrolled in the study. In addition, a control group of 30 males aged 20 - 36 years (24.0 ± 3.6 years) with a normal BMI (< 25 kg/m2) participated in the study for comparison. Each subject completed the ocular surface disease index (OSDI), followed by the TER measurement using a handheld VapoMeter. RESULTS: Significant differences (Wilcoxon test; p = 0.002 and 0.001) were found between the median scores of the OSDI (10.3 [3.7] vs. 5.9 [7.2]) and TER (35.5 [13.1] vs. 15.5 [12.8] g/m2 h) in the study and control groups, respectively. The OSDI indicated dry eye in 60.0% of subjects in the study group (n = 18). The TER measurements showed that 76.7% of subjects in the study group (n = 23) had dry eyes. A medium correlation (r = 0.569; p = 0.001) was found between the OSDI scores and TER measurements. CONCLUSIONS: The means of the tear evaporation rate and the ocular surface disease index scores are significantly higher in subjects with a high BMI compared with the control group. Therefore, a high BMI is considered a risk factor for dry eye. The measurement of the tear evaporation rate using a handheld VapoMeter is a simple and rapid method to detect dry eyes in combination with other tools.

The Breastfeeding Effect On The Tear Film Of Women: An Observational Study.

OBJECTIVE: To assess the tear film parameters in breastfeeding women. satisfaction. Methods: The observational study was conducted at the College of Applied Medical Sciences, Riyadh, Saudi Arabia, from December 15, 2021, to February 12, 2022, and comprised healthy women aged 18-40 years who had no ocular diseases. Breastfeeding women were in group A and non-breastfeeding women formed the control group B. Ocular surface disease index, phenol red thread, and tear ferning tests were used in that order to assess the tear film for all the subjects. A gap of 5 minutes was allowed between phenol red thread and tear ferning tests. Data was analysed using SPSS, version 22. RESULTS: Of the 50 subjects, 25(50%) were in group A with mean age 30.4±5.9 years having a mean breastfeeding period of 5.4±5.0 months. The remaining 25(50%) women were in group B with mean age 28.5±2.1 years. Significant differences were found between the groups for ocular surface disease index, phenol red thread, and tear ferning (p<0.05). Significant moderate correlation was found between tear ferning grades and breastfeeding duration (p<0.05). Conclusion: Breastfeeding was found to increase dry eye symptoms in women.

Effect of Ultraviolet-A and Riboflavin treatment on the architecture of the center and periphery of normal rat cornea: 7 days post treatment.

Corneal collagen cross-linking (CXL) is a treatment that is widely applied to halt the progression of ectatic diseases such as keratoconus by creating biomechanical strength in the cornea. Most of the studies assessed the effect of the CXL on the cornea without any differentiation of its effect between periphery and the center of the untreated control cornea especially after the 7 days of CXL application. We investigate the ultrastructural changes in the architecture of the center and periphery of rat corneas, 7 days after standard CXL application. Five Wistar rats (10 corneas) were used in the present study. The left eye corneas (5 mm area) were de-epithelialized and irradiated with standard CXL application using riboflavin and Ultraviolet-A (UVA) (3 mW/cm2 for 30 min). The right eye corneas were used as a control. The sclera-cornea button was removed and processed for electron microscopy. Digital images were captured with a bottom mounted Quemesa camera and analyzed using the iTEM software. The ultrastructure of epithelium, hemi-desmosomes, Bowman's layer and stroma were organized in both untreated control and CXL rat cornea in both untreated control and CXL rat cornea. Within the same CXL cornea, both the collagen fibril (CF) diameter and interfibrillar spacing at the center were significantly smaller compared to the peripheral diameter and spacing of the cornea. When comparing the untreated control and CXL cornea, the central interfibrillar spacing of the CXL cornea was significantly smaller than the central spacing the untreated control cornea. In the CXL cornea the peripheral spacing was significantly higher compared to the peripheral interfibrillar spacing of the untreated control cornea. Within the CXL cornea, the proteoglycans (PGs) area and density of the periphery was significantly higher compared to the area and density of the center of the cornea. It suggests that CXL was more effective at the periphery of the cornea. This could be due to the higher amount of leucine rich PG lumican and higher diffusion of oxygen and riboflavin at the periphery cornea.

Assessment of Tear Film Parameters in Smokers and Subjects with a High Body Mass Index.

SIGNIFICANCE: The current study compares the ocular tear film parameters in three different groups using a single noninvasive, practical, and easy-to-use tool. PURPOSE: This study aimed to assess the tear film in smokers, those with a high body mass index (BMI), and healthy subjects using the EASYTEAR view+. METHODS: Thirty men with a high BMI (>25 kg/m2; 24.4 ± 6.4 years), 30 smokers (25.1 ± 6.1 years), and 30 healthy subjects (22.2 ± 3.5 years) were recruited. Each subject completed the Ocular Surface Disease Index, followed by the assessment of noninvasive tear breakup time, tear meniscus height (TMH), and lipid layer patterns (LLPs). RESULTS: Significant differences were found in the median TMH scores between smokers and healthy subjects (P = .03) and between subjects with a high BMI and the healthy ones (P = .04). The median LLP score was significantly (P < .001) higher in normal subjects (4.0 [1.0]) than in smokers (2.4 [1.0]) and subjects with high BMI (2.0 [1.3]). For subjects with a high BMI, the noninvasive tear breakup time score was strongly correlated (Spearman rank correlation coefficient; r) with TMH (r = 0.552, P = .002) and LLP (r = 0.555, P = .001). The LLP showed that grade B (lipid layer thickness, 30 to 50 nm; more compact) was common in subjects with a high BMI, grade C (50 to 80 nm, gray waves) was predominant in smokers, and grade D (~80 nm, dense white-blue layer) represented the majority of normal eye subjects. CONCLUSIONS: Smokers and individuals with a high BMI showed significantly lower lipid layer grades and tear meniscus height scores compared with the control group. The assessment of tear film parameters using the EASYTEAR view+ supports the findings of previous studies that implicate smoking and high BMI as risk factors for dry eye.

The Effect of the Addition of Electrolyte Solutions on the Ferning Patterns of Tears Collected from Normal Eye Subjects.

SIGNIFICANCE: The current study is the first report to describe the improvement of ferning patterns of human tears using electrolyte solutions. The results can help in the production of new artificial tears to improve the quality of tears. PURPOSE: This study aimed to investigate the effect of the addition of different volumes of various electrolyte solutions on ferning patterns of human tears. METHODS: Tear samples (20 µL) were collected from the right eye of 13 subjects (5 men and 5 women) aged 19 to 36 years (27.1 ± 5.1 years) with normal eyes. Then, 1 µL of each tear sample was dried on a microscopic glass slide, and obtained ferns were observed using light microscopy and graded using the 5-point tear ferning (TF) grading scale. Homogenous mixtures of each tear sample (0.5 µL) and different volumes (0.5 to 5 µL) of each electrolyte were prepared. A sample (1 µL) of each mixture was dried, and the ferns obtained were graded and compared with those of the corresponding tears collected from subjects before the addition of electrolyte solutions. RESULTS: After the addition of electrolyte solutions, the TF grades of tears collected from healthy humans were generally improved. Significant (Wilcoxon test) improvements have been seen in the TF grades of the tear samples after the addition of a solution of potassium chloride (P = .03), calcium chloride (P = .01), magnesium chloride hexahydrate (P = .002), and sodium dihydrogen phosphate (P = .002). No significant improvements in the TF grades were seen after the addition of sodium chloride solution (P = .33). CONCLUSIONS: Ferning grades of human tears improved with most of the electrolytes used.

Evaluation of the Significance of Tear Ferning Patterns in beta-Thalassemia Patients.

AIM: This study was designed to evaluate the tear film in beta-thalassemia patients using tear ferning (TF) and phenol red thread (PRT) tests. METHODS: Forty beta-thalassemia patients, aged 18 - 38 years (25.7 ± 6.0 years), along with a control group of 40 age-matched subjects with healthy eyes completed the study. All subjects completed the ocular surface disease index (OSDI) first, followed by the TF and PRT tests with a 5-minute gap between the tests. RESULTS: Significant differences (Wilcoxon test, p < 0.05) were observed between the beta-thalassemia and control groups in all scores. Among beta-thalassemia patients, OSDI scores indicated eye dryness in 35 subjects (87.5%). PRT showed dryness in 31 subjects (77.5%) in the right and left eyes, and the TF grades were ≥ 2 for the tears collected from 35 subjects (87.5%). There was a strong correlation (r = 0.851, p = 0.001) between the PRT measurements in the right and left eyes. There was a medium correlation between OSDI and TF scores (r = 0.309, p = 0.026) and between OSDI and age (r = 0.365, p = 0.010). Age had a moderate negative correlation (r = - 0.328, p = 0.019) with the PRT obtained from the right eye. CONCLUSION: Significant ocular dryness symptom was observed in beta-thalassemia patients, based on the scores collected from TF and PRT tests. Beta-thalassemia patients develop dry eyes, possibly due to several factors, including reduced tear secretion. Therefore, it is important to regularly evaluate both the quality and quantity of tears in patients with beta-thalassemia.

Evaluation of lacrimal production, osmolarity, crystallization, proteomic profile, and biochemistry of capuchin monkeys' tear film.

BACKGROUND: To evaluate the composition and characteristics of capuchin monkey (CM) tear film. METHODS: Eleven CM (Sapajus sp.) was evaluated. Strip meniscometry test (SMT), osmolarity, and tear ferning test (TFT) (by Rolando and Masmali scales) were assessed. Tear protein profile (SDS-PAGE), and total protein, albumin, urea, glucose, and cholesterol levels in tear film and blood serum were screened. RESULTS: Median ± semi-interquatil range for SMT and osmolarity values were 8.0 ± 1.625 and 303.0 ± 9.875, respectively. TFT for Rolando was 2.0 ± 0.5, and Masmali was 2.0 ± 0.0. Monkeys's tear obtained type II and III for Rolando, and 1 and 2 for Masmali. Tear components showed protein bands among 23-217 kDa, and presence of albumin, urea, glucose, and cholesterol. CONCLUSIONS: The results of SMT, osmolarity, TFT, SDS-PAGE, and tear biochemistry may serve as a reference baseline for CM, and the data may serve as a basis for future experimental model evaluations.

Investigation of Ocular Tear Ferning in Controlled and Uncontrolled Diabetic Subjects.

OBJECTIVES: To investigate the ocular tear film in controlled and uncontrolled diabetes mellitus (DM) subjects and the relationship between dry eye and diabetes. METHODS: One hundred twenty-four diabetes adults (65 male and 59 female, with 62 controlled and 62 uncontrolled DM) were assessed by McMonnies dry eye questionnaire, tear break-up time (TBUT), phenol red thread (PRT) test. In addition, tear samples were collected from the lower tear meniscus of right eyes and dried onto glass slides under controlled room temperature (25°C) and humidity (40%). The glass slides were observed using a digital microscopy and the tear ferning (TF) patterns observed were graded based on Masmali TF grading scale. Patients with a HbA1c value below 6.5% were defined as "controlled DM" and those with a HbA1c value above 6.5% were defined as "uncontrolled DM." The Spearman's correlation coefficient was used to determine the relationship between various tests. RESULTS: Several subjects having dry eye varied depending on the test used. McMonnies questionnaire scores suggested that 28 subjects (23%) showed dry eye (score >14.5), of whom 23 subjects (82%) showed uncontrolled diabetes. The TF patterns showed that 44 subjects (35.5%) showed dry eyes (Grade ≥2), of whom 32 subjects (72.7%) showed uncontrolled diabetes. Phenol red thread test found that 46 subjects (37%) showed dry eye (wetting <10 mm), of whom 38 subjects (82.6%) showed uncontrolled diabetes. Tear break-up time found that 57 subjects (46%) showed dry eye (time <10 sec), of whom 45 subjects (78.9%) showed uncontrolled diabetes. In controlled diabetic subjects, TF grades showed medium negative correlations with both TBUT and PRT (-0.374 and -0.349, respectively). In uncontrolled subjects, TF grades have a strong negative correlation with TBUT (-0.539) and a medium negative correlation with PRT (-0.410). CONCLUSIONS: Dry eye disease is common in diabetic subjects, particularly in people with poor diabetic control. Uncontrolled blood glucose level seemed to be a risk factor for dry eye syndrome. Tear ferning test showed a correlation between diabetes and dry eye in diabetic subjects and can be used as a reliable test to evaluate the quality of the ocular tear film.

Tear ferning test in healthy dogs.

PURPOSE: To evaluate and compare three tear sampling methods using two grading scales for administering the tear ferning test (TFT) to healthy dogs. METHODS: In total, 90 dogs (180 eyes) were subjected to tear sampling using millimetered strips, reused after the Schirmer tear test (STT) (Schirmer group, SG). Then, the dogs were subdivided into three groups according to sampling approach: micropipette (MPG), microcapillary (MCG), and Schirmer sample 2 (S2G). The collected tears were dried on a clean microscope glass slide at room temperature and humidity. The ferning patterns were observed under a polarized light microscope and classified according to the Rolando and Masmali grading scales. RESULTS: Although all three methods were feasible, the STT was easier to perform in clinical settings. Type I and Grade 1 were the most commonly observed (64.17% and 61.7%, respectively) regardless of collection method. There was no significant difference between the STT median values and the TFT classifications. CONCLUSIONS: The TFT is appropriate for dogs and can be performed using the three suggested sampling methods, with a higher frequency of Type I and Grade 1. Thus, it is possible to use both grading scales in the classification of tear ferning in dogs.

Repeatability and Diurnal Variation of Tear Ferning Test.

OBJECTIVES: To investigate tear ferning (TF) test repeatability between sessions by observing changes in the tear fern pattern during the day. METHODS: Twenty-three healthy young adults (15 men and 8 women), ranging in age from 20 to 32 years (mean ± SD: 22.9 ± 3.3 years) without signs or symptoms of dry eye disease, ocular disease, or contact lens wear were enrolled in the study. Schirmer I, tear break-up time (TBUT) test, and McMonnies questionnaire were used to screen volunteers. Schirmer I and TBUT tests were applied to both eyes in each subject. Four samples of tear fluid were collected from the right eye of each subject using glass capillaries at set intervals during a single day (9 AM, 11 AM, 2 PM, and 4 PM). The TF patterns obtained from samples were classified according to the Masmali TF grading scale to increments of 0.1. RESULTS: The median values obtained from the McMonnies, Schirmer, and TBUT tests were 4.0 ± 2.0, 30.0 ± 7.0 mm (OD), and 16.0 ± 10.0 sec (OD), respectively. There were no statistically significant differences between the TF grades for tear samples collected at different times of the day (Wilks' Lambda, P = 0.351). The majority (84.8%) of TF grades was between 0.0 and 1.5; the remaining 15.2% of subjects had TF between grades 1.6 and 1.9. The overall mean grade for the TF was 1.1 ± 0.3. There were small insignificant correlations between TF grades and the McMonnies questionnaire (r = 0.1.30) and TBUT (r = 0.248) and a negligible correlation with Schirmer test (r = -0.046). CONCLUSIONS: The results found no significant differences within the TF for tear samples collected at different times of the day, suggesting that there is little diurnal variation evident.

Investigation of tear osmolarity using the TearLab Osmolarity System in normal adults in Saudi Arabia.

OBJECTIVES: To investigate the repeatability and average tear osmolarity using the new lab-on-chip TearLab technology device in normal subjects living in Saudi Arabia, a hot climate country, and to compare the average readings with data from previous studies. METHODS: Thirty healthy young adults (13 males and 17 females) who ranged in age from 20 to 40 years (mean±SD: 28.57±5.58 years) with no symptoms of dry eyes or ocular disease, who did not wear contact lenses, and were not pregnant or breastfeeding were enrolled in the study. For inclusion criteria, all subjects were examined under a slit-lamp to verify the absence of ocular surface disorders. Moreover, phenol red thread, tear breakup time (TBUT) tests, and McMonnies questionnaire were used to exclude dry eyes. Three measurements of tear osmolarity were performed in 1 eye (at 5-min intervals) using the TearLab osmometer. RESULTS: The mean score on the McMonnies questionnaire was 6±2.9. The mean values obtained from the phenol red thread and TBUT tests were 22±7.7 mm (OD), 21.5±6.6 mm (OS) and 12±1.7 s (OD), 12.5±1.6 s (OS), respectively. There were no statistically significant differences between the osmolarity readings (Wilks' lambda; P=0.945). Tear osmolarity results confirmed that 50% of subjects had readings of 299 to 312 mOsm/L, 40% had readings of 288 to 299 mOsm/L, and 10% had readings of 277 to 288 mOsm/L. The overall mean osmolarity was 299.06±7.65 mOsm/L. There was a medium correlation between osmolarity and the McMonnies questionnaire and a strong negative correlation between osmolarity and TBUT values. CONCLUSIONS: We found that the average osmolarity for subjects living in Saudi Arabia was 299.06±7.65 mOsm/L, which falls within the reference range and is in agreement with published results (298.0-301.9±7.2-16.0 mOsm/L). Osmolarity was positively correlated with McMonnies questionnaire and negatively correlated with TBUT values. The TearLab osmolarity system test showed good precision in repeated measurements. This is the first report of use of the TearLab osmolarity system to assess tear film in normal Saudi adults.

Comparative study of repeatability of phenol red thread test versus Schirmer test in normal adults in Saudi Arabia.

OBJECTIVE: To investigate the repeatability of the phenol red thread (PRT) and Schirmer tests in healthy Saudi adults. Additionally, we compared the PRT mean value with those reported previously because of significant differences between Hong Kong-Chinese, Japanese, and US subjects. METHODS: Thirty healthy young Saudi adults (7 men and 23 women; 60 eyes) with a mean age of 22.37±2.31 years were recruited. Participants provided consent and completed a McMonnies questionnaire. Dry eye subjects were excluded based on this questionnaire and slit-lamp examination. Both eyes of each subject were examined using the PRT and Schirmer tests. Each test was repeated three times for each eye, five minutes apart. The PRT test was applied first, followed by the Schirmer test 15 minutes later under anesthesia to avoid any inconsistency of the measurements due to reflex tears. RESULTS: The PRT and Schirmer tests both demonstrated good repeatability with no statistically significant differences. There was a poor correlation between the 2 tests (r=0.286). There was no statistically significant difference between OD and OS in the two tests. The mean PRT values in normal Saudi subjects were higher than those reported previously for Hong Kong-Chinese, Japanese, and US subjects. CONCLUSIONS: Both the PRT and Schirmer tests displayed good repeatability; however, there was a poor correlation between the tests, as reported previously. The mean PRT value in normal Saudis was higher, when compared with those reported previously for other ethnic groups.

Crystal structure of 2-tert-butyl-1,3-thia-zolo[4,5-b]pyridine.

The title compound, C10H12N2S, does not contain any strong hydrogen-bond donors but two long C-H⋯N contacts are observed in the crystal structure, with the most linear inter-action linking mol-ecules along [010]. The ellipsoids of the tert-butyl group indicate large librational motion.

Evaluation of tear meniscus height and lipid layer patterns in the tear film in domestic cats: An observational study.

Background: Healthy vision in humans and animals requires a stable tear film. The environmental factor could affect the status of the tear film. Therefore, assessing the tear film in animals is essential to avoid visual system disturbance. Aim: The current research used a noninvasive device to evaluate the tear meniscus height (TMH) and lipid layer pattern (LLP) in domestic cats. In addition, the scores were compared with those of humans with healthy eyes. Methods: Fifty-four domestic cats (28 males and 26 females; mean ± SD = 13.9 ± 18.2 months) were randomly selected and included in the study. The cats were healthy, without any ocular disorders or diseases. Fifty-four healthy eye subjects (27 males and 27 females; mean ± SD = 25.6 ± 5.1 years) were randomly recruited and took part in the study for comparison. EASYTEAR View+ was used, for the first time, to assess the tear film parameters on the right eye of each subject. The examiner allowed a 5-minute gap between the tests. Each test was performed by the same examiner three times, followed by calculating the mean scores. Results: Significant differences (Mann-Whitney U test) were found in the median scores of LLP (p = 0.009) between cats and subjects with healthy eyes. The median TMH score was higher in cats (0.18 mm) than in humans (0.14). However, no significant difference (Mann-Whitney U Test, p = 0.210) exists in the TMH scores between cats and humans. The LLP analysis indicated that a dense white-blue lipid layer (grade 4 or D; lipid layer thickness, LLT, = approximately 80 nm) was predominant in both cats (N = 24, 44.4%) and humans (N = 29, 53.7%). In comparison, variable colors lipid layer (grade 5 or E; LLT = 90-140 nm) was a minority in cats (N = 5, 9.3%) and common in humans (N = 16, 29.6%). The statistical analysis indicated medium correlations between cats' TMH and LLP scores (r = 0.431, p < 0.01) and between age and TMH scores in humans (r = 0.440, p < 0.01). In addition, it indicated a weak correlation (r = 0.291, p < 0.05) between the LLP scores in cats and humans. Conclusion: Assessing animals' tear film is essential to avoid any ocular disorders. EASYTEAR View+ is efficiently used to evaluate domestic cats' TMH and LLP. Cats have thicker lipid layers and longer TMH comparable to those reported for humans with healthy eyes.

Assessment of lipid layer patterns in domestic dogs and rabbits: an observational study.

Background: Maintaining a stable tear film is crucial for having healthy human and animal vision. Animals are expected to have thicker lipid layers than humans due to living in high-temperature and humid environments. Aim: The study aimed to evaluate the lipid layer patterns (LLPs) in Arabian dogs and rabbits using a non-invasive, practical, and easy-to-use device and compare them to humans with healthy eyes. Methods: The study included 75 domestic Arabian dogs (42 males and 33 females; mean ± SD = 6.1 ± 12.7 months) and 75 rabbits (37 males and 38 females; mean ± SD = 3.1 ± 3.4 months). In addition, 75 individuals with healthy eyes (39 males and 36 females; mean ± SD = 25.7 ± 5.0 years) were included for comparison. EASYTEAR View+ assessed the LLP in each animal's and individual's right eye. Results: The median LLP grades significantly differed between dogs and humans (Mann-Whitney U test, p < 0.001). Similarly, the LLP grades differed significantly between rabbits and humans (Mann-Whitney U test, p < 0.001). No significant difference (Mann-Whitney U test) in the LLP grades between dogs and rabbits was found. The analysis indicated that most dogs had either an A (34.7%) or a B grade (37.3%). Similarly, rabbits had predominantly A or 1 (46.7%) and B (30.7%) grades. On the other hand, humans had predominantly D (53.3%) and E (30.7%) grades. Conclusion: The EASYTEAR View+ has been employed to assess LLP in dogs and rabbits, and the measurements were compared to those of humans with normal ocular health. Dogs and rabbits have thinner lipid layers than healthy humans.

Exploring the Relationship Between Bakhour Use and Respiratory Health: A Cross-Sectional Study in the Jazan Region, Saudi Arabia.

Background: Despite deep cultural traditions, incense burning significantly impacts respiratory health. Effects of Arabian bakhour remain unknown in Saudi Arabia's Jazan region with prevalent use. This cross-sectional study addresses this gap by investigating bakhour exposure and respiratory diseases. Methods: This was descriptive cross-sectional study conducted in Jazan area, Saudi Arabia, from October 2023 to March 2024. A total of 1612 participants age more than 18 years, both gender and resident of Jazan Area were included. Those aged less than 18 years were excluded. SPSS v 26 was used for data analysis. Results: The sample (n=1612) had a mean age of 29±11 years and was 63% female. Bakhour use was nearly universal (98%), especially using coal (73%). Higher bakhour frequency significantly associated with increased cough (p<0.01) and dyspnea (p<0.01). Certain bakhour types linked to greater allergic rhinitis prevalence (p<0.01). Regression analysis revealed cough during bakhour use worsened respiratory health (increased respiratory score) by 3.89 times (95% CI 1.13-6.64; p=0.006) while dyspnea increased the score by 7.48 times (95% CI 4.70-10.25; p<0.001). Conclusion: This study provides valuable insights into the association between Bakhour use and respiratory health in the Jazan region. The findings emphasize the need for further research and public health interventions to mitigate potential respiratory risks associated with Bakhour use.

(Z)-N-(2,6-Diiso-propyl-phen-yl)-4-nitro-benzimidoyl chloride.

In the title compound, C19H21ClN2O2, the aromatic rings are approximately perpendicular to each other, subtending a dihedral angle of 87.7 (1)°. In the crystal, the 4-nitro-phenyl groups of pairs of neighbouring mol-ecules are parallel and oriented head-to-tail with a ring centroid-centroid distance of 3.9247 (12) Å, leading to a π-π inter-action between the pair. The faces of each phenyl ring of the 2,6-diiso-propyl-phenyl group inter-act with two different groups, viz. a chloro group of an adjacent mol-ecule on one side and the edge of the 4-nitro-phenyl ring of a second mol-ecule on the other side.

(E)-3-(4-Bromo-5-methyl-thio-phen-2-yl)acrylo-nitrile.

In the title structure, C8H6BrNS, the molecules are planar with the exception of the methyl H atoms. In the crystal, molecules are linked by intermolecular C-H⋯N interactions to form ribbons parallel to the b axis. Groups of ribbons are arranged in a herringbone pattern to form a layered structure parallel to the ab plane.

4-(5-{2-[5-(4-Cyano-phen-yl)-3-methyl-thio-phen-2-yl]-3,3,4,4,5,5-hexa-fluoro-cyclo-pent-1-en-1-yl}-4-methyl-thio-phen-2-yl)benzo-nitrile chloro-form hemisolvate.

The crystal structure of the title compound, C29H16F6N2S2·0.5CHCl3, consists of mol-ecules with disordered perfluoro-cyclo-pentene rings [occupancy ratio 0.685 (3):0.315 (3)] and close F⋯F contacts (in the range 2.45-2.73 Å) between mol-ecules. The short contacts are associated with the disorder. The dihedral angle between thiophene rings is 57.44 (8)°. The 5-(4-cyano-phen-yl)-3-methyl-2-thienyl groups of adjacent mol-ecules are parallel, leading to zigzag chains of mol-ecules along [101]. The dihedral angles between each thiophene ring and its adjacent cyanobenzene ring are 8.9 (2) and 7.15 (10)°.

Effect of monovalent electrolyte solutions on the human tear ferning pattern.

PURPOSE: To investigate the effect of the addition of a low concentration of sodium chloride (NaCl) and potassium chloride (KCl) solutions on the tear ferning (TF) patterns of tears collected from humans. METHODS: A tear sample (20 µL) was collected from the right eye of 23 males and 7 females (25.4 ± 6.6 years). The tears were collected in one sitting for healthy subjects (N = 13). For dry eye participants (N = 17), the tear samples were collected in two separate settings with five minutes gap in between. A sample (1 µL) from each tear was dried on a glass slide, and the obtained ferns were observed using a microscope and graded using the five-point TF grading scale. Mixtures of tear samples (0.5 µL) and different volumes (0.5-2.5 µL) of each electrolyte (10-30 mg in 100 mL of water) solution were prepared, and their TF patterns were recorded and compared with those of the corresponding pure tears. RESULTS: Significant improvements (Wilcoxon test, P < 0.001) have been seen in the TF grades of the tear samples after the addition of NaCl and KCl solutions. A significant difference (Wilcoxon test, P = 0.016) was found between the TF grades when NaCl and KCl solutions were added to the tear samples. The TF grades of pure tears collected from dry-eye subjects ranged from 2.1 to 3.5, based on the five points grading scale, and decreased to be in the range of 0.4 to 1.6 after the addition of electrolyte solutions. While the TF grades of pure tears collected from normal-eye ranged from 1.2 to 1.9 and improved after the addition of electrolyte solution to be in the range of 0.4 to 1.5. CONCLUSIONS: The TF test was used in vitro to assess the impact of the addition of a low concentration of sodium and potassium chloride solutions on tears collected from humans. The TF grades of human tears significantly improved after the addition of either sodium or potassium chloride solution. The mechanism for the improvement in TF grades due to the addition of electrolyte solutions must be investigated.