Flexible Cast Research Articles

A single Angiofil-latex injection for both radiological and anatomical assessment of arterial territories in the limbs

IntroductionPostmortem evaluation of the human vascular system has a long history, with advancements ranging from dissections to modern imaging techniques like computed tomography (CT scan). This study designs a novel combination of Angiofil, a liquid radiopaque polymer, and latex, a flexible cast material, for cadaveric vascular analysis. Material & methodsThe aim was to synergize the advantages of both components, providing accurate radiological images and optimal dissection conditions. Three arterial territories (lateral circumflex femoral artery, profunda brachii artery, and radial artery) were injected and assessed through CT scans and dissections. ResultsThe Angiofil-latex mixture allowed successful visualization of the vascular networks, offering a simple, reproducible, and non-toxic approach. Quantitative assessments of the three territories, including diameters and lengths, showed comparable results between CT scan and dissection. DiscussionThe technique precision and versatility make it an accessible and valuable tool for anatomical studies, potentially extending its application to MRI analyses. Overall, the Angiofil-latex combination presents a cost-effective solution for researchers, offering enhanced visibility and detailed anatomical insights for various applications, including anatomical variation studies.

Syntheses and characterizations of high refractive index and low birefringence polyimides containing spirobifluorene in the side chain

Two new diamine monomers having a spirobifluorene structure were synthesized through four steps, and polymerized with three different dianhydrides (PMDA, CBDA and 6FDA) to obtain six polyimides with spirobifluorene structure in the side chain. All the resulting polyimides displayed excellent thermal stability and high glass transition temperature. These polyimides synthesized from CBDA and 6FDA showed good solubility in typical organic solvents such as NMP, DMF and DMSO. Transparent and flexible cast films can be obtained from soluble polyimides or poly(amic acid) solution. The transmittance of polyimide films was higher than 90% in the visible wavelength range (higher than 80% in case of polyimide containing PMDA). The refractive indices of the result polyimides were found to be in the range from 1.6343 to 1.7007, which is higher than that of normal polymers. In addition, the optical birefringences of these polyimides were extremely low (0.0005–0.0014). The high refractive index and low birefringence of these polyimides as well as other descent physical and thermal properties would offer them possible applications in high performance optical materials such as flexible substrates.

Enhanced electroactive β phase in three phase PVDF/CaCO3/nanoclay composites: Effect of micro‐CaCO3 and uniaxial stretching

ABSTRACTIn this study, electroactive polar phase transformation and crystallinity of poly(vinylidene fluoride) (PVDF)‐based composites, such as PVDF/CaCO3/nanoclay, is explored as a function of micro‐CaCO3 fraction and draw ratio (R) of uniaxial stretching. Composites including PVDF/clay, PVDF/CaCO3 and most importantly PVDF/CaCO3/clay with varying fraction of micro‐CaCO3 were extruded into homogenous and flexible cast films. Characterization via Fourier transform infrared spectroscopy, X‐ray diffraction, and differential scanning calorimetry (DSC) confirmed the presence of β phase in all the composites incorporated with micro‐CaCO3 and nanoclay either individually (i.e., PVDF/CaCO3 and PVDF/clay films, respectively) or together (i.e., PVDF/CaCO3/nanoclay composites). Interestingly, a gradual but significant improvement in this electroactive phase (β phase) was obtained with successive increment in CaCO3 content into a fixed composition of PVDF and nanoclay (PVDF/CaCO3/clay composites). Further increment in β phase content was obtained via uniaxial stretching to different draw ratios and at a temperature of 90 °C, where for PVDF/CaCO3/clay (especially, 100–35‐3 and 100–40‐3) samples almost no α phase was observed irrespective of R. Conversely, the crystallinity of melt extruded samples decreased gradually all the way with CaCO3 concentration in PVDF/CaCO3/clay composites compared to the neat PVDF while increased gradually with increasing draw ratio. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44940.

Matrix Shear-Lag Parameter in a Shape Memory Alloy-Actuator-Reinforced Silicon Elastomer

The excellent qualities possessed by silicon elastomer when used in designing flexible parts of mechanical systems, make it imperative that we analyze its deformations and distributed axial forces in a matrix of shape memory alloy (SMA) fibers designed as possible appendages for gripping robots. The essence of these analyses is to determine the shear-lag parameter which has influence on the axial distributed forces proposed as a gauge for testing the structure in a high yield, high force and high strain mechanical environment. The insertion of SMA fibers in flexible rods cast using silicon elastomer results in the deformation of the host medium once shape recovery of the fiber occurs. This paper aims to analyze the mechanics of the said shape recovery in a modeled silicon elastomer rod with a single off-axis reinforced SMA actuator. The compressive force distribution mechanism and the bending moment caused by phase transformation in the design are determined using an approximate analytical model. The deformations on the structure proposed as an appendage on gripping robots were further analyzed by determining their equations of equilibrium, force factors and their comparative shear-lag models to be able to estimate the force distribution on the structure.

Chairside technique for expediting indirect interim restorations

Figure 2. Hot melt adhesive-made flexible cast. The use of flexible casts and dies for the chairside fabrication of interim restorations has been reported to overcome the drawbacks of the direct technique and provide a safe and biocompatible fabrication process. Because of the elasticity of these casts, removing the interim restoration after complete setting is easy, and the integrity of the casts is maintained. Unlike stone casts, the flexible cast can be reused if a new interim restoration is needed later. Different elastomeric impression materials and consistencies have been used to make flexible casts. Although materials such as polyvinyl siloxane have excellent dimensional stability, they are relatively expensive and adhere to the already set impression material. For this reason, a second alginate impression is usually made to produce the flexible cast. To overcome these limitations, this article proposes the use of hot melt adhesive material (HMA) for the fabrication of flexible casts. HMA is a thermoplastic material usually supplied in sticks, which are melted using an electric gun. It typically consists of a base material such as an ethylene-vinyl acetate copolymer with additives such as wax, resins, plasticizers, and pigments. HMAs do not adhere to elastomeric impression materials. This allows easy separation of impressions made with any material, including polyvinyl siloxane without the need for a separating agent. Obtaining the flexible cast from the definitive impression eliminates the need for an additional impression, reduces the time needed for the procedure, and improves the accuracy of flexible cast details. HMAs are also less expensive than elastomeric impression materials.

Synthesis and property of 9,9′-spirobifluorene-containing aromatic polyesters as optical polymers with high refractive index and low birefringence

C2-Symmetric 9,9′-spirobifluorene-containing polyesters (PEs) were synthesized by polycondensation of 2,2′-dihydroxy-9,9′-spirobifluorene (1) with bis(acyl chloride)s (2) at 230 °C in diphenylether. The molecular weights of PEs 3a–3f were sufficiently high (Mw 13,400–41,600). PEs displayed high thermal stability. The glass transition temperatures (Tg) estimated by differential scanning calorimetry analysis appeared in a range 177–352 °C depending on the spacer structure, while the 5% decomposition temperatures (Td5) measured by thermogravimetric analysis were over 416 °C both under nitrogen atmosphere and in air. PEs showed good solubility in typical organic solvents such as CHCl3 and THF easily to afford the tough, transparent, and flexible cast films. The transmittance of the polymer films reached over 90% in the wavelength range from ca. 410–900 nm. In addition, PEs exhibited higher refractive index rather than that of commercially available 9,9-diarylfluorene-containing PE, in addition to very low degree of birefringence presumably due to the C2-symmetric structure.

Fluorene‐rich high performance polyesters: Synthesis and characterization of 9,9‐fluorenylidene and 2,7‐fluorenylene‐based polyesters with excellent optical property

AbstractPolyesters PEs containing high content of fluorene units in their backbones were synthesized from 9,9‐diarene‐substituted fluorene diols (1) and fluorene‐based diacid chlorides (2) by high temperature polycondensation at 185 °C in diphenyl ether. The molecular weights of the polyesters PE1‐PE5 were in a range of Mw 25,000–165,000. The polyesters displayed their high thermostability: the glass transition temperatures (Tg) by differential scanning calorimetry analysis ranged from 109 to 217 °C, while the 10% weight loss temperatures (Td10) measured by thermogravimetric analysis were over 400 °C in nitrogen and 395 °C in air. The polyesters had good solubility in most common organic solvents such as chloroform and toluene and gave tough, transparent and flexible cast films. The transmittance of the films was over 80% in the wavelength range from 450 to 700 nm in any PEs. The PEs exhibited high refractive index values around 1.65, while they had very low degree of birefringence. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2549–2556, 2008

Characterization of Biodegradable Composite Films Prepared from Blends of Poly(Vinyl Alcohol), Cornstarch, and Lignocellulosic Fiber

Several composite blends of poly(vinyl alcohol) (PVA) and lignocellulosic fibers were prepared and characterized. Cohesive and flexible cast films were obtained by blending lignocellulosic fibers derived from orange waste and PVA with or without cornstarch. Films were evaluated for their thermal stability, water permeability and biodegradation properties. Thermogravimetric analysis (TGA) indicated the suitability of formulations for melt processing, and for application as mulch films in fields at much higher temperatures. Composite films were permeable to water, but at the same time able to maintain consistency and composition upon drying. Chemical crosslinking of starch, fiber and PVA, all hydroxyl functionalized polymers, by hexamethoxymethylmelamine (HMMM) improved water resistance in films. Films generally biodegraded within 30 days in soil, achieving between 50–80% mineralization. Both starch and lignocellulosic fiber degraded much more rapidly than PVA. Interestingly, addition of fiber to formulations enhanced the PVA degradation.

Use of a flexible cast for the indirect fabrication of provisional restorations

Efficient fabrication of a clinically acceptable provisional restoration for a fixed partial denture is an important part of treatment success. Fabrication of provisional restorations that uses the indirect technique produces accurate fitting provisional restorations without the chemical and thermal irritation associated with direct fabrication. With a typodont model, an indirect method is presented that uses an elastic cast for fabrication of multiple unit provisional restorations for fixed partial dentures. The cast is available within 6 minutes of impression making, can be trimmed with a sharp scalpel, and provides flexibility that allows easy separation of the acrylic provisional from the cast. The cast can also be used to evaluate the clinical acceptability of the preparations before impression making. This method has also been successfully used for the fabrication of acrylic provisional restorations for onlay preparations. (J Prosthet Dent 1999;82:90-3.)

Use of a flexible cast for fabrication of multiple post-coping overdenture restorations

Direct intraoral fabrication of multiple post-coping restorations for an overdenture in the same arch can be a time-consuming chairside clinical procedure. In addition, accurate intraoral fabrication of resin patterns with intracrevicular margins is not always possible as a result of limited access. This article presents a direct-indirect method that uses an elastic cast for fabrication of multiple post-coping restorations with intracrevicular margins. Custom post patterns are fabricated directly in the root canal with autopolymerizing resin (Duralay). An impression is made of the remaining tooth structure, which also includes the post patterns, and a flexible cast is poured chairside. The cast is available within 6 to 8 minutes of impression making and can be trimmed similar to a stone die. The procedure also provides flexibility that allows separation of the cast from the impression without fracture of the custom post pattern or cast. The fabrication of the post-coping restoration can be completed in the laboratory, or if necessary, completed chairside and verified intraorally, before dismissing the patient. (J Prosthet Dent 1999;81:365-8.)

An Application of Flexible Plastic Cast to Upper Extremity Disorders.

A newly made flexible plastic cast has special characteristics, such as flexibility by trimming part of the finished cast. We tried to use the material for the orthotic treatment of various hand and finger disorders. We treated the patients with median nerve palsy (21 cases), ulnar nerve palsy (3 cases), radial nerve palsy (7 cases) and rheumatoid arthritis (12 cases) with the material. In cases of peripheral nerve palsy, quick-made wrist hand orthoses constructed with this material could support paralytic muscles effectively without disturbing the activities of daily living. In rheumatoid arthritis, instability of wrist of finger was effectively stabilized with this material. Orthoses made of the material have superior characteristics such as: 1) Flexibility can be changed by trimming after stiffening. 2) The cast can be easily cut with scissors. 3) The orthoses are comfortable to wear.

A silicon rubber cast of the cavities in the temporal bone as a teaching aid in human anatomy

A technique is described for producing a more flexible cast of the cavities in the temporal bone for teaching purposes. Instead of using rigid polymers to produce the model with all its inherent disadvantages, silicon rubber is used. It has the advantage that the cast is easier to produce, it is more robust when handled, and teachers can bend portions of the model to demonstrate underlying structures.

肝鋳型標本とその臨床応用シリコンゴムを用いた肝鋳型標本の作製法

肝鋳型標本とその臨床応用シリコンゴムを用いた肝鋳型標本の作製法

A method of making a flexible cast of the lung.

A method of making a flexible cast of the lung.

Laying and Repairing a Six-Inch Wrought Iron Submarine Pipe Line at Portland, Maine

Journal AWWAVolume 8, Issue 6 p. 616-626 Article Laying and Repairing a Six-Inch Wrought Iron Submarine Pipe Line at Portland, Maine† James W. Graham, James W. Graham16 Casco Street, Portland, Me.Search for more papers by this author James W. Graham, James W. Graham16 Casco Street, Portland, Me.Search for more papers by this author First published: 01 November 1921 https://doi.org/10.1002/j.1551-8833.1921.tb11791.x †Presented at the Cleveland Convention, June 9, 1921. Discussion is invited and should be sent to the Editor. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume8, Issue6November 1921Pages 616-626 RelatedInformation