33 research outputs found
Tensioned fabric structures in jungle design shape
Tensioned fabric structure became a topic of discussion for many engineers because of its lightweight. This structure manages to resist all loads such as wind and rain. Due to the light in weight, tensioned fabric structures are normally designed to be in the form of equal tensioned surface or minimal surface. The major objective of this study is to generate three Jungle forms with minimal surface or equal tensioned surface to apply in infrastructure and to propose an alternative for engineers to consider the Jungle minimal surface models. More study found out that minimal surface of tensioned fabric structure help in sustainability the environment. The form of tensioned fabric structure of this structure was applied using mathematical equation which was then generated through MATLAB. The three Jungle forms tensioned fabric structure show minimal surface. The study might inspire the engineers to implement Jungle shape in tensioned fabric structures
Waste materials as extender of bituminous binder: a review
Bitumen is a hydrocarbon material which can be largely obtained from crude petroleum distillation. It used widely in flexible pavement construction as a binder that binds the aggregate. Flexible pavements make up around 95% of the pavement in entire world. The quality of the materials used in the flexible pavement is essential for its performance. The modification of bituminous binders using modifiers is applied to improve the quality and properties of bitumen. Due to the limitation of crude oil, higher price, and impact of bitumen on the environment, an efficient, cost-effective, and environmentally friendly modifier for the modification of bituminous binders is vital in road industry. This paper aims to provides a review and propose the waste materials that can be used as modifier or bitumen extender. Among these waste materials, silicon, rubber, cooking oil (mix with other modifiers) lignin and calcium lignosulfonate shown a promising results as bitumen extender. Furthermore, the cost analysis of the modified bituminous binders was also look upon. The findings from this study recommend lignin among the extender being compared. Lignin can be mixed directly in the bitumen with a minimal process involved. Moreover, lignin is a bio-based waste materials and the second most abundant organic material on earth, after cellulose. With 25% replacement of bitumen, lignin reduces the consumption of non-renewable bitumen and has a great potential to be used in pavement construction
Programmable Shunt Valves for Pediatric Hydrocephalus: 22-Year Experience from a Singapore Children's Hospital
10.3390/brainsci11111548BRAIN SCIENCES111
Programmable Shunt Valves for Pediatric Hydrocephalus: 22-Year Experience from a Singapore Children’s Hospital
(1) Background: pediatric hydrocephalus is a challenging condition. Programmable shunt valves (PSV) have been increasingly used. This study is undertaken to firstly, to objectively evaluate the efficacy of PSV as a treatment modality for pediatric hydrocephalus; and next, review its associated patient outcomes at our institution. Secondary objectives include the assessment of our indications for PSV, and corroboration of our results with published literature. (2) Methods: this is an ethics-approved, retrospective study. Variables of interest include age, gender, hydrocephalus etiology, shunt failure rates and incidence of adjustments made per PSV. Data including shunt failure, implant survival, and utility comparisons between PSV types are subjected to statistical analyses. (3) Results: in this case, 51 patients with PSV are identified for this study, with 32 index and 19 revision shunts. There are 3 cases of shunt failure (6%). The mean number of adjustments per PSV is 1.82 times and the mean number of adjustments made per PSV is significantly lower for MEDTRONIC™ Strata PSVs compared with others (p = 0.031). Next, PSV patients that are adjusted more frequently include cases of shunt revisions, PSVs inserted due to CSF over-drainage and tumor-related hydrocephalus. (4) Conclusion: we describe our institutional experience of PSV use in pediatric hydrocephalus and its advantages in a subset of patients whose opening pressures are uncertain and evolving
Reshaping and customization of SMILE-derived biological lenticules for intrastromal implantation
Purpose: To evaluate the feasibility of excimer laser reshaping of biological lenticules available after small incision lenticule extraction (SMILE). Methods: Fresh and cryopreserved SMILE-derived human lenticules underwent excimer laser ablation for stromal reshaping. The treatment effects in the lasered group were compared with the nonlasered group with respect to changes in surface functional groups (by Fourier transform infrared spectroscopy [FTIR]) and surface morphology (by scanning electron microscopy [SEM] and atomic force microscopy [AFM]). Ten SMILE-derived porcine lenticules, five nonlasered (107-μm thick, −6 diopter [D] spherical power) and five excimer lasered (50% thickness reduction), were implanted into a 120-μm stromal pocket of 10 porcine eyes. Corneal thickness and topography were assessed before and after implantation. Results: FTIR illustrated prominent changes in the lipid profile. The collagen structure was also affected by the laser treatment but to a lesser extent. SEM exhibited a more regular surface for the lasered lenticules, confirmed by the lower mean Rz value (290.1 ± 96.1 nm vs. 380.9 ± 92.6 nm, P = 0.045) on AFM. The lasered porcine lenticules were thinner than the nonlasered controls during overhydration (132 ± 26 μm vs. 233 ± 23 μm, P < 0.001) and after 5 hours in a moist chamber (46 ± 3 μm vs. 57 ± 3 μm, P < 0.001). After implantation, the nonlasered group showed a tendency toward a greater increase in axial keratometry (6.63 ± 2.17 D vs. 5.60 ± 3.79 D, P = 0.613) and elevation (18.6 ± 15.4 vs. 15.2 ± 5.5, P = 0.656) than the lasered group. Conclusions: Excimer laser ablation may be feasible for thinning and reshaping of SMILE-derived lenticules before reimplantation or allogenic transplantation. However, controlled lenticule dehydration before ablation is necessary in order to allow stromal thinning.NRF (Natl Research Foundation, S’pore)NMRC (Natl Medical Research Council, S’pore)Published versio
Corneal remodelling and topography following biological inlay implantation with combined crosslinking in a rabbit model
Abstract Implantation of biological corneal inlays, derived from small incision lenticule extraction, may be a feasible method for surgical management of refractive and corneal diseases. However, the refractive outcome is dependent on stromal remodelling of both the inlay and recipient stroma. This study aimed to investigate the refractive changes and tissue responses following implantation of 2.5-mm biological inlays with or without corneal collagen crosslinking (CXL) in a rabbit model. Prior to implantation, rotational rheometry demonstrated an almost two-fold increase in corneal stiffness after CXL. After implantation, haze gradually subsided in the CXL-treated inlays (p = 0.001), whereas the untreated inlays preserved their clarity (p = 0.75). In-vivo confocal microscopy revealed reduced keratocyte cell count at the interface of the CXL inlays at week 8. Following initial steepening, regression was observed in anterior mean curvature from week 1 to 12, being most prominent for the non-CXL subgroups (non-CXL: −12.3 ± 2.6D vs CXL: −2.3 ± 4.4D at 90 μm depth, p = 0.03; non-CXL: −12.4 ± 8.0D vs CXL: −5.0 ± 4.0D at 120 μm depth, p = 0.22). Immunohistochemical analysis revealed comparable tissue responses in CXL and untreated subgroups. Our findings suggest that CXL of biological inlays may reduce the time before refractive stabilization, but longer postoperative steroid treatment is necessary in order to reduce postoperative haze
Visual Impairment in Old and Very Old Community-dwelling Asian Adults
10.1016/j.ophtha.2016.06.036OPHTHALMOLOGY123112436-243