Robotic fabrication of space structures and systems : : an investigation of...

Issued as Administrative report, Project E-20-52

Lower tear meniscus in computer reading task with and without soft contact lens

Dry eye is the major contributor to computer vision syndrome. The reductions in the blink rate and amplitude have been considered as the possible mechanisms leading to this condition. The purpose of this study is to evaluate the changes in the lower tear meniscus heights and areas in the computer reading task, in dry eye subjects, with and without soft contact lenses. In this quasi-experimental study, 39 subjects (with mean age of 21.2 ± 2.4 years), with dry eye, were enrolled.  The lower tear meniscus height and area (TMH, TMA) of the right eye was captured by Spectral Optical Coherence Tomography before and after 45 minutes of reading task behind desktop 17” Cathode Ray Tube monitors. The same procedure was performed after the insertion of the hydrogel soft contact lenses with 58% water content. The results of TMHs, TMAs were analyzed with a repeated measures analysis of variance (ANOVA) with two within-subject factors.: The mean ± standard error of  TMH and TMA pre and post computer tasks were 283.6± 25.4 µm, 0.029±0.005 mm2, 297.6±20.7 µm , 0.036 ± 0.005 mm2 respectively. After contact lens insertion, the mean TMH and TMA pre and post computer task were 231.6 ± 10.6 µm, 0.020±0.0019 mm2, 213.0±9.0 µm, 0.018 ± 0.0011 mm2, respectively. Repeated measures analysis of variance showed that the changes in TMH (P=0.86) and TMA (P=0.37) after computer task, were not statistically significant, while the insertion of the soft contact lens had reduced the TMH and TMA significantly (P<0.001 for both). After 45 minutes of reading task behind desktop monitors, the tear volume has not changed, with and without high water SCLs. A reduction in tear volume might be expected with longer duration of computer task or at late hours of the day. The creation of a more stable tear film should be considered in the management strategies for shorter duration of work behind desktop monitors

Comparison of an Italian Chart with an Iranian Chart in Visual Acuity Measurement

Background: Taking visual acuity is an important part of an eye routine examination. This study was conducted to compare visual acuity measured using an Iranian digital tumbling E chart with visual acuity measured using an Italian digital tumbling E chart as a familiar foreign chart.Materials and Methods: This study was carried out on 200 participants (400 eyes; healthy n=40, glaucoma n=40, retinal disorders n=40, post lasik n=40, corneal n=40) with mean age 44.28 years. Visual acuity of both eyes of half of the subjects (n=100, n=20 from each group), was first measured using the Italian digital chart and then measured using Iranian digital chart. Visual acuity of the rest of subjects (n=100, n=200 from each group) was first measured using the Iranian digital chart and then measured using the Italian digital chart. Measured visual acuities were recorded in logMAR notation.Results: The mean of the Iranian and Italian Tumbling E chart is 0.280±0.012 and 0.277±0.012, respectively. Paired t-test used to evaluate the mean difference between two groups (p=0.721) indicated that there was no statistically significant difference between means of the two tests. Spearman correlation coefficient for the results of both tests was 0.942 (p<0.001), which was statistically significant and could be categorized as a strong positive correlation.Conclusion: The two digital Tumbling E charts acted similarly at different levels of acuity in different disorders. However, the Iranian chart requires a more accurate design for optotypes of the lower acuity lines in order to obtain more accurate measurement of visual acuities in healthy subjects

Comparison of Two Marketed Hydroxypropyl Methylcellulose Based Artificial Tear Drops in Young Patients with Dry Eye Syndrome

Background: Artificial tears have been among the first line of therapy in management of Dry Eye Syndrome (DES). This study was conducted to compare a local artificial tear with an imported one in reduction of DES. This comparison would help to evaluate the cost and benefits of each drop in the proper management of DES.Materials and Methods: In this double-blind randomized clinical trial study, a total 65 students meeting our inclusion criteria for DES entered the study. The OSDI questionnaire, TBUT, corneal and conjunctival staining and Schirmer test, were performed. The patients were divided into two groups by block randomization. Group 1 received first drop and group 2 received second drop. Both groups were instructed to use the drops 4 times a day for 14 days. The same tests were performed by the same examiner who was blind to the treatment type after two weeks. Repeated measured ANOVA was used to analyze the data.Results: A total of 58 patients completed the study. In both groups, after the intervention, the OSDI scores (P<0.001), TBUT score (P=0.041), corneal (P<0.001) and conjunctival staining scores (P<0.001) showed improvement in compare to those before the intervention. However, the Schirmer test score did not show significantly difference before and after intervention. In comparing two groups the OSDI scores, the TBUT score, the corneal and conjunctival staining scores and the Schirmer scores did not show statistically significant difference.Conclusion: The two artificial tears equally reduced the symptoms and signs of DES in two weeks

Changes in corneal biomechanical parameters in keratoconus eyes with various severities after corneal cross-linking (CXL)::A comparative study

Objectives To compare changes in corneal biomechanical parameters one year after corneal cross-linking (CXL) in keratoconus (KCN) eyes of different severities. Methods Seventy-five eyes with mild, moderate, and severe grades of KCN (n = 24, 31, and 20 eyes, respectively) that were treated with CXL, based upon the standard Dresden protocol, were included. The corneal biomechanical assessment was performed using Corvis ST and Ocular Response Analyzer (ORA). Changes in Corvis's dynamic corneal response (DCR) parameters and ORA's derived parameters (corneal hysteresis (CH), and corneal resistance factor (CRF)) were assessed whilst the corneal thickness and intraocular pressure were considered as covariates. Results There was no statistically significant difference in the corneal biomechanical parameters obtained using both devices after surgery separately in different KCN grades, except for the deformation amplitude (DA) in the severe KCN group (P = 0.017). Changes in the classic parameters of the highest concavity phase of Corvis ST (peak distance, radius, and DA) were more positive and in the newer parameters (integrated inverse radius (IIR), deformation amplitude ratio (DAR)) more negative in the severe group compared to the other groups. Also, the mean change in CH (P = 0.710), and CRF (P = 0.565), showed a negative shift in higher grades of KCN; however, there was no significant difference in the mean changes of all parameters between different groups. (P > 0.05) Conclusions Similar changes in the Corvis ST and ORA parameters in mild, moderate, and severe KCN indicate biomechanical stability and the effective role of CXL in stopping the progressive nature of keratoconus in eyes of varying severities one year after CXL

Factors influencing the selection of delay analysis methodologies

This is the post-print version of the final paper published in International Journal of Project Management. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2007 Elsevier B.V.Delays and disruption to contractors’ progress are a major source of claims and disputes in the construction industry. Often at the heart of the matter in dispute is the question of the extent of each contracting party’s responsibility for the project delay. Various delay analysis methodologies have been developed over the years as aids to answering this question. This paper reports on a study into the factors that influence analysts’ selection from these methodologies. Eighteen factors were identified through literature review and pilot surveys and then ranked on their relative importance based on data collected in a nation-wide survey of UK construction organisations. Factor analysis was used to reduce the factors into 6 group factors: project characteristics, contractual requirements, characteristics of baseline programme, cost proportionality, timing of the analysis and record availability

Impact of changing computer technology on hydrologic and water resource modeling

The increasing availability of substantial computer power at relatively low costs and the increasing ease of using computer graphics, of communicating with other computers and data bases, and of programming using high-level problem-oriented computer languages, is providing new opportunities and challenges for those developing and using hydrologic and water resources models. This paper reviews some of the progress made towards the development and application of computer support systems designed to aid those involved in analyzing hydrologic data and in operating, managing, or planning water resource facilities. Such systems of hardware and software are being designed to allow direct and easy access to a broad and heterogeneous group of users. These systems often combine data-base management; simulation and optimization techniques; symbolic colored displays; heuristic, qualitative approaches; and possibly artificial intelligence methods in an interactive, user-controlled, easily accessible interface. Individuals involved in the use of such systems are not only those with technical training, but also those representing different interest groups and having non-technical backgrounds. The essential difference between what is happening now and the more traditional off-line, non-interactive approaches is that instead of generating solutions to specific problems, model developers are now beginning to deliver, in a much more useful and user-friendly form, computer-based turnkey systems for exploring, analyzing and synthesizing plans or policies. Such tools permit the user to evaluate alternative solutions based on his or her own objectives and subjective judgments in an interactive learning and decision-making process

Construction risk analysis

Issued as Annual progress report and Final report, Project no. E-20-66

Knowledge-based expert systems and robotics

Issued as Final report, Project no. E-20-G0

Construction innovations in slipforming concrete buildings

Issued as Final project report, Project no. E-20-68