In this paper, foldable structures with scissor-like elements are investigated and then based on constraints geometric design of these structures is formulated for any curved shape. Method of geometric design of foldable structures with any curvature is investigated. Using given connections to these systems in this paper, two models with fixed geometry and variable geometry is designed and constructed on real scale, based on this formulation. Correct behavior of these models is a sample to proof the applicability of formulation and connections. To find the optimal geometry of barrel vaults that structure has minimum displacement, based on formulation, some Macro files are programmed to model barrels with any curvature with ANSYS. Many of barrels are analyzed as linear and geometrically nonlinear, and graph of displacements are illustrated. The results display that there is a special height for any span with two characteristics; the displacement of structure is minimum and the difference of linear and geometrically nonlinear analysis is minimum.

Foldable-deployable Structures are often used as emergency and temporary shelters after disasters or earthquakes. In this paper, generation of foldable structures with scissor-like elements is formulated for various shapes with no geometric limitations. Non-linear analyses are performed and compared for designing foldable structures. The optimum height to span ratio is obtained for barrel vault type of foldable structures. Geometric instability of low height barrel vaults, are also investigated by finding buckling loads.

Background: Biofilm formation of Staphylococcus epidermidis is a major etiological factor of inducing device-related infections.Objectives: The ability of biofilm formation by the S. epidermidis was assessed in vitro on two brands of foldable (hydrophilic) and two brands of rigid (hydrophobic) intraocular lens materials in order to investigate the role of lens material in postoperative endophthalmitis.Materials and Methods: To ensure reproducibility of biofilm formation on intraocular lenses, two strains of S. epidermidis and three quantification methods were performed. The S. epidermidis strains, DSMZ3270 (biofilm-producer) and ATCC12228 (non-biofilm-producer) were applied. Organisms were cultivated on disks of different brands of foldable hydrophilic Intra Ocular Lens (IOL) made of acrylic (Didar, Iran; (A) and Omni, India; (B)), and rigid hydrophobic IOL made of polymethyl methacrylate (PMMA; Didar, Iran; (C) and Hexavision, France; (D)). Biofilms were stained with crystal violet (CV) dye, which is an index of biofilm formation. The bacterial population was counted after biofilm homogenization. Scanning electron microscopy (SEM) was performed to examine the extent of biofilm formation.Results: Adherence of DSMZ3270 strain on both types of foldable and rigid IOLs, was significantly more than ATCC12228 (P<0.001-0.05 and, P<0.01-0.05, respectively). The bacterial populations between the lenses were significantly different (P<0.05). Subsequent studies demonstrated significant differences between brands of foldable and PMMA IOLs. According to statistical analyses the incubation time influenced the biofilm formation on both types of IOLs which meant that by increasing incubation time, the biofilm formation increased. According to the SEM pictures, biofilm seems to be lysed at 72 hours.Conclusions: These data demonstrated that the attachment of bacteria to hydrophilic acrylic IOLs was more than hydrophobic PMMA ones independent of the brand. According to these results the bacterial strain might have more hydrophilic properties. Augmenting the biomass of biofilm by passing of time demonstrated the key role of time in biofilm formation on the IOL surfaces. The differences between IOL brands in the biofilm formation indicated the influence of design parameters for IOLs.

Dear Editor, We are writing to share our observations regarding the article “, Multiple pit defects of unknown etiology in a foldable hydrophobic intraocular lens”,by Thabit et al. [1] We would like to congratulate the authors for documenting this interesting phenomenon. The authors mentioned no obvious reason for the formation of pit-like deposits on the anterior surface of the intraocular lens (IOL). We want to disagree with this statement in that IOL pit formation is a well-established phenomenon where opacification of hydrophilic acrylic IOLs occurs after corneal transplantations such as penetrating keratoplasty and Descemet’, s stripping endothelial keratoplasty (DSEK). [2]..

In this article the genetic algorithm is employed to optimize scissor-link foldable structures. The Advantage of using GA lies in the fact that the discrete spaces can be optimized without any Complexity. Here displacement method is used for analysis with uniplet elements.      

PRESENTATION: A 56‑ year‑ old female patient presented to our clinic for a routine follow‑ up appointment after penetrating keratoplasty and cataract surgery (triple procedure) for a deep corneal scar due to previous herpetic keratitis. The procedure was performed 9 months before the recent presentation. Her unaided visual acuity was 2/10 OD and 10/10 OS. On slit‑ lamp examination, the corneal graft OD appeared clear, and the anterior segment OS was healthy with bilateral pseudophakia. However, we unexpectedly observed that there were multiple pits on the anterior surface of the intraocular lens (IOL) OD [Figure 1], which was a hydrophilic, one‑ piece, in‑ the‑ bag IOL. The patient did not undergo any YAG capsulotomy or vitrectomy with silicone oil tamponade. She had not experienced any intraocular infection or corneal graft rejection episodes since undergoing ocular surgery...

Purpose: To evaluate the near visual performance of an accommodative intraocular lens (IOL); Tetraflex, in comparison to a standard monofocal foldable IOL in cataract surgery. Setting: Eye Research Center, Farabi Eye Hospital, Department of Ophthalmology, Tehran University of Medical Sciences, Iran. Methods: Forty six eyes of 23 patients with cataract underwent phacoemulsification and accommodative IOL (Tetraflex) implantation bilaterally (case group). The same number of age- atched control group were implanted a foldable monofocal IOL bilaterally (control group). Outcome measures were uncorrected distance visual acuity (UCDVA), uncorrected near visual acuity (UCNVA), manifest refraction, best corrected distance visual acuity (BCDVA), distance corrected near visual acuity (DCNVA), and the amplitude of accommodation up to 6 months after surgery. Results: The final BCDVA was better than 20/25 in all eyes. Mean±standard deviation (SD) DCNVA in the accommodative IOL group (0.69±0.25) was significantly higher than monofocal foldable IOL (0.18±0.09) six months following surgery (P<0.001). Eighty nine percent (41 eyes of 46) of the accommodative IOL group achieved DCNVA of 20/40 or better 6 months after surgery. At 1 month after surgery, mean±SD accommodation in the case group was 3.86±1.11 D compared to 0.27±0.18 D in the control group (P<0.001). Six months after operation, 95.7% of the patients in the case group had 2.5 D or more accommodation compared to a mean of 0.48 D in the control group. Conclusion: The accommodative IOL provides both enhanced near vision and good distance vision 6 month after surgery. It seems that patient's dependence to near add will be decreased and they can have a good range of clear vision.

Transformable elements of all different types have become increasingly utilized in architecture in order to respond to varying building conditions. Adaptive strategies and geometries found in nature have inspired a need for buildings to respond to the changing environments in their immediate context. In today’s realm of environmental awareness, transformable architecture has the ability to respond to environmental conditions, and in turn increase the efficiency, occupant comfort and energy consumption of building systems. This paper discusses different movements, mechanisms and applications of transformable architecture, specifically foldable systems using pantographic elements. Case studies have been examined and evaluated in order to develop a final façade system with the ability to control the penetration of sunlight to a building under variable conditions. Sunlight can enable the passive heating of space, but may be detrimental and increase cooling loads and occupant discomfort through the summer months. In order to reduce the consumption of energy throughout the year, an occupant or computer controlled transformable façade system, like the one proposed, can be utilized. The proposed design seeks to emulate the adaptive nature of plants and animals when it comes to being light sensitive or light responsive. This shading system, when applied to buildings, will attempt to provide a solution which can help buildings become more transformable, and ultimately, more efficient. Despite of many transformable proposals, this four-panel shading system is to transform itself responsively and is able to function not only in fully open configuration but also in various stages of deployment. The proposed design not only provides occupants with natural lighting conditions or protection from solar glare, it optimizes solar heat gain through the heating season or mitigates it throughout the cooling season, satisfying both the energy efficiency and occupant comfort.

Purpose: To compare the optical properties of hydrophilic and hydrophobic intraocular lenses (IOLs) containing UV-absorber and to determine their chemical composition.Methods: Optical properties of different foldable hydrophilic and hydrophobic as well as non-foldable hydrophobic polymethylmetacrylate (PMMA) IOLs were evaluated in three powers of 15, 22 and 25 diopters. Optical properties were measured using UV-VIS (UV-Visible) spectroscopy between wavelengths 200 and 800 nm and chemical structure characteristics were determined by ATR (attenuated total reflectance) spectroscopy.Results: ATR spectroscopy revealed that foldable hydrophilic and hydrophobic IOLs and non-foldable hydrophobic IOLs were respectively composed of hydroxyethylmethacrylate, a copolymer of phenylethylacrylate and phenylethylmethacrylate, and PMMA (in accordance with manufacturer’s claim).Cut-off points of the lenses were found to be around 350-420 nm. Increasing the IOL power from 15 to 22 diopters did not significantly change the cut-off points of foldable hydrophobic IOLs, however a considerable cut-off shift to higher wavelengths was noted when power increased to 25 diopters. PMMA lenses showed a constant cut-off at 400 nm for all power values.Conclusion: The increase in power is associated with absorption of lower energy UV radiation and shift of cut-off points to higher wavelengths in hydrophobic IOLs but with no considerable effect on cut-off points in PMMA IOLs.