Heat-shrinkable Tube Research Articles

Magnetic resonance imaging using linear magneto-inductive waveguides

Magneto-inductive waveguides are arrays of magnetically coupled, lumped element resonators, which support slow waves at radio frequency. Their use in internal magnetic resonance imaging (MRI), where they may provide an intrinsically safe method of signal detection and transmission, is described. A catheter-based receiver formed from a thin-film printed circuit mounted on a tubular scaffold using heat-shrink tubing is demonstrated, and its electrical response and imaging sensitivity are explained in terms of the excitation and propagation of magneto-inductive waves. The theoretical predictions are confirmed using the results of electrical measurement and 1H MRI at 1.5 T, and imaging is achieved over a total length greater than 1.5 m using a single receiver.

Temperature-sensitive mechanical LPFG using contractive force of heat-shrinkable tube

A novel temperature-sensitive mechanical long period fiber grating (LPFG) fabricated utilizing the photo-elastic effect is proposed. Our proposed LPFG consists of a telecommunication optical fiber, a metric screw, and the heat-shrinkable tube, which are commercially available. The heat-shrinkable tube and the metric screw are used to obtain the grating along the single-mode fiber. The gratings are achieved by pressing the optical fiber between the heat-shrinkable tube and the metric screw due to the contractive force of its tube. By changing the temperature, the resonance loss is tuned due to the thermal expansion of the heat-shrinkable tube. Operating mechanism of thermally tunable characteristics of our LPFG are also described from a viewpoint of the coupling coefficient.

Electron beam accelerators—trends in radiation processing technology for industrial and environmental applications in Latin America and the Caribbean

The radiation processing technology for industrial and environmental applications has been developed and used worldwide. In Latin America and the Caribbean and particularly in Brazil there are 24 and 16 industrial electron beam accelerators (EBA) respectively with energy from 200keV to 10MeV, operating in private companies and governmental institutions to enhance the physical and chemical properties of materials. However, there are more than 1500 high-current electron beam accelerators in commercial use throughout the world. The major needs and end-use markets for these electron beam (EB) units are R and D, wire and electric cables, heat shrinkable tubes and films, PE foams, tires, components, semiconductors and multilayer packaging films. Nowadays, the emerging opportunities in Latin America and the Caribbean are paints, adhesives and coatings cure in order to eliminate VOCs and for less energy use than thermal process; disinfestations of seeds; and films and multilayer packaging irradiation. For low-energy EBA (from 150keV to 300keV). For mid-energy EBA (from 300keV to 5MeV), they are flue gas treatment (SO2 and NOX removal); composite and nanocomposite materials; biodegradable composites based on biorenewable resources; human tissue sterilization; carbon and silicon carbide fibers irradiation; irradiated grafting ion-exchange membranes for fuel cells application; electrocatalysts nanoparticles production; and natural polymers irradiation and biodegradable blends production. For high-energy EBA (from 5MeV to 10MeV), they are sterilization of medical, pharmaceutical and biological products; gemstone enhancement; treatment of industrial and domestic effluents and sludge; preservation and disinfestations of foods and agricultural products; soil disinfestations; lignocellulosic material irradiation as a pretreatment to produce ethanol biofuel; decontamination of pesticide packing; solid residues remediation; organic compounds removal from wastewater; and treatment of effluent from petroleum production units and liquid irradiation process to treat vessel water ballast. On the other hand, there is a growing need of mobile EB facilities for different applications in South America.

Development of an Electric Charge-Tunable Micro-column for Capillary Liquid Chromatography

An electric charge-tunable micro-column (CTMC) was developed as a precolumn for reversed-phase capillary chromatography using conductive carbon fibers as the stationary phase. The carbon fibers, which constitute one electrode, are packed into a heat-shrinkable tube, which is attached to a stainless-steel column body. The mobile phase flows into CTMC through a stainless-steel tube that acts as a counter electrode. The retention times for hydrophobic and ionic compounds are controlled by the applied potential. The characteristics, such as the electrolysis efficiency and shift in retention factor, were evaluated. As a case study, estrogens in spiked beef were analyzed by capillary chromatography. With no applied potential, the resolution between the unknown peak and estriol and the recoveries of estriol were 0.81 and 65.5%, respectively. These values improved to 1.2 and 78.8%, respectively, upon applying +500 mV. These results indicate that a high-resolution capillary chromatography system can be achieved with CTMC.

2A1-E09 繰り出し式能動ホースの湾曲手法に関する研究(アクチュエータの機構と制御(1))

We have proposed an active hose to explore the narrow and complex space. The hose has the following two characteristics. One is that top of the hose grows by air pressure from within, and the grown part of the hose becomes hard and guide hose. The other is that the diameter of the hose can be changed according to the number of tube units. In this paper, the method that enables the hose to bend is described using heat shrinkable tube newly. This mechanism is confirmed by experiments.

A Modular Heat-Shrink-Packaged Check Valve With High Pressure Shutoff

A novel check valve featuring adhesiveless packaging in heat-shrink tubing and dual regulation of in-plane flow is presented. The modular design enables simple replacement of valve components to modify valve behavior and performance. The specific design is intended for low-profile fluidic applications requiring flow control, such as drug delivery devices. The heat-shrink packaging scheme is extremely robust and can withstand >; 2000 mmHg (266.6 kPa) without leakage. Three different valve geometries were investigated and evaluated with theoretical and finite-element modeling analyses. Repeated flow regulation experiments on a fully packaged, hydrated valve demonstrated flow regulation between 25 and 2000 mmHg (3.33-266.6 kPa) and leak-free closure up to 500 mmHg (66.7 kPa) of reverse pressure with no observed stiction. The valve closing time constants were also determined.

Nano-sized particles formed by pulsed discharge of powders

Exploding wire and pulsed wire discharge are effective methods to form nano-sized particles. They are based on evaporation of thin metal wires by applied large electric current as the principle to form particles. Many kinds of wires have been used to form nano-sized particles so far. However, materials which are not sufficiently ductile to form thin wires are unsuitable for the methods. We have developed a method for powders to be held between electrodes by using heat-shrinkable tubes and discharged for evaporation. Nano-sized intermetallic NiAl compound particles were synthesized from mixed powders of Al and Ni. Si powder could be discharged by sealing with a thin Al wire, and nano-sized Si particles were formed. Utilizing this technique, various metal powders can be used for raw materials in pulsed discharge.

Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk of thromboemboli formation1,2,3. We have developed a method to line the inside surface of Ti tubes with autologous blood-derived human or porcine endothelial progenitor cells (EPCs)4. By implanting Ti tubes containing a confluent layer of porcine EPCs in the inferior vena cava (IVC) of pigs, we tested the improved biocompatibility of the cell-seeded surface in the prothrombotic environment of a large animal model and compared it to unmodified bare metal surfaces5,6,7 (Figure 1). This method can be used to endothelialize devices within minutes of implantation and test their antithrombotic function in vivo. Peripheral blood was obtained from 50 kg Yorkshire swine and its mononuclear cell fraction cultured to isolate EPCs4,8. Ti tubes (9.4 mm ID) were pre-cut into three 4.5 cm longitudinal sections and reassembled with heat-shrink tubing. A seeding device was built, which allows for slow rotation of the Ti tubes. We performed a laparotomy on the pigs and externalized the intestine and urinary bladder. Sharp and blunt dissection was used to skeletonize the IVC from its bifurcation distal to the right renal artery proximal. The Ti tubes were then filled with fluorescently-labeled autologous EPC suspension and rotated at 10 RPH x 30 min to achieve uniform cell-coating9. After administration of 100 USP/ kg heparin, both ends of the IVC and a lumbar vein were clamped. A 4 cm veinotomy was performed and the device inserted and filled with phosphate-buffered saline. As the veinotomy was closed with a 4-0 Prolene running suture, one clamp was removed to de-air the IVC. At the end of the procedure, the fascia was approximated with 0-PDS (polydioxanone suture), the subcutaneous space closed with 2-0 Vicryl and the skin stapled closed.After 3 - 21 days, pigs were euthanized, the device explanted en-block and fixed. The Ti tubes were disassembled and the inner surfaces imaged with a fluorescent microscope.We found that the bare metal Ti tubes fully occluded whereas the EPC-seeded tubes remained patent. Further, we were able to demonstrate a confluent layer of EPCs on the inside blood-contacting surface.Concluding, our technology can be used to endothelialize Ti tubes within minutes of implantation with autologous EPCs to prevent thrombosis of the device. Our surgical method allows for testing the improved biocompatibility of such modified devices with minimal blood loss and EPC-seeded surface disruption.

Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk of thromboemboli formation1,2,3. We have developed a method to line the inside surface of Ti tubes with autologous blood-derived human or porcine endothelial progenitor cells (EPCs)4. By implanting Ti tubes containing a confluent layer of porcine EPCs in the inferior vena cava (IVC) of pigs, we tested the improved biocompatibility of the cell-seeded surface in the prothrombotic environment of a large animal model and compared it to unmodified bare metal surfaces5,6,7 (Figure 1). This method can be used to endothelialize devices within minutes of implantation and test their antithrombotic function in vivo. Peripheral blood was obtained from 50 kg Yorkshire swine and its mononuclear cell fraction cultured to isolate EPCs4,8. Ti tubes (9.4 mm ID) were pre-cut into three 4.5 cm longitudinal sections and reassembled with heat-shrink tubing. A seeding device was built, which allows for slow rotation of the Ti tubes. We performed a laparotomy on the pigs and externalized the intestine and urinary bladder. Sharp and blunt dissection was used to skeletonize the IVC from its bifurcation distal to the right renal artery proximal. The Ti tubes were then filled with fluorescently-labeled autologous EPC suspension and rotated at 10 RPH x 30 min to achieve uniform cell-coating9. After administration of 100 USP/ kg heparin, both ends of the IVC and a lumbar vein were clamped. A 4 cm veinotomy was performed and the device inserted and filled with phosphate-buffered saline. As the veinotomy was closed with a 4-0 Prolene running suture, one clamp was removed to de-air the IVC. At the end of the procedure, the fascia was approximated with 0-PDS (polydioxanone suture), the subcutaneous space closed with 2-0 Vicryl and the skin stapled closed. After 3 - 21 days, pigs were euthanized, the device explanted en-block and fixed. The Ti tubes were disassembled and the inner surfaces imaged with a fluorescent microscope. We found that the bare metal Ti tubes fully occluded whereas the EPC-seeded tubes remained patent. Further, we were able to demonstrate a confluent layer of EPCs on the inside blood-contacting surface. Concluding, our technology can be used to endothelialize Ti tubes within minutes of implantation with autologous EPCs to prevent thrombosis of the device. Our surgical method allows for testing the improved biocompatibility of such modified devices with minimal blood loss and EPC-seeded surface disruption.

Fracture load of tooth–implant‐retained zirconia ceramic fixed dental prostheses: effect of span length and preparation design

Evaluation of the effect of different span length and preparation designs on the fracture load of tooth-implant-supported fixed dental prostheses (TIFDPs) manufactured from yttrium-stabilized zirconia frameworks. Forty-eight TIFDPs were manufactured using a CAD/CAM system and veneered with a press ceramic. Rigidly mounted implants (SLA, diameter 4.1 mm, length 10 mm) in the molar region with a titanium abutment were embedded in PMMA bases pairwise with premolars. All premolars were covered with heat-shrink tubing to simulate physiological tooth mobility. Six different test groups were prepared (a) differing in the preparation design of the premolar (inlay [i]; crown [c]), (b) the material of the premolar (metal [m]; natural human [h]) and (c) the length of the TIFDPs (3-unit [3]; 4-unit [4]). All TIFDPs underwent thermomechanical loading (TCML) (10,000 × 6.5°/60°; 6 × 10(5) × 50 N). The load to fracture (N) was measured and fracture sites were evaluated macroscopically. None of the restorations failed during TCML. The mean fracture loads (standard deviations) were 1,522 N (249) for the 3-unit, inlay-retained TIFDPs on a metal abutment tooth (3-im), 1,910 N (165) for the 3-cm group, 1,049 N (183) for group 4-im, 1,274 N (282) for group 4-cm, 1,229 N (174) for group 4-ih and 911 N (205) for group 4-ch. Initial damages within the veneering ceramic occurred before the final failure of the restoration. The corresponding loads were 24-52% lower than the fracture load values. All restorations tested could withstand the mastication forces expected. Fracture-load values for 3- and 4-unit inlay-crown and crown-crown-retained TIFDPs should spur further clinical investigation.

Fabrication of a pen-shaped portable biochemical reaction system based on magnetic bead manipulation

A pen-shaped platform that is similar to a mechanical pencil is proposed for producing a portable reaction system. A reaction unit, as the key component in the system, was produced by using a heat shrinkable tube. A mechanical pencil supplied by Mitsubishi Pencil Co. Ltd was used as the pen-shaped platform for driving the reaction cylinder. It was actuated using an inchworm motion. We confirmed that the magnetic beads were successfully manipulated in the droplet in the cylinder-shaped reaction units.

Nano-sized Particles Formed by Pulsed Discharge of Powders Sealed in Heat-shrinkable Tubes

Pulsed wire discharge has been developed as a method to form nano-sized particles, wherein a large electrical current pulse is passed through a thin metal wire. Various wire materials have been used to form nano-sized particles by this method so far. However, materials which are not sufficiently ductile to form thin wires are unsuitable for this method. We have developed a new method for powders to be discharged to form nano-scale particles instead of wires. The powders were placed in heat-shrinkable tubes and sealed by heating. Short metal wires were set at both the ends of each tube for electrical connection to the electrodes of the discharge equipment. These tubes were set in a chamber whose atmosphere could be controlled. A large current pulse was then applied to the powders in the tubes. SiC particles with a cubic crystalline structure were synthesized in N2 gas from mixed powders of Si and C with a C/Si molar ratio of unity. However, mostly the Si phase remained in the particles. Then, mixed powders with a C/Si ratio of 2 were discharged. The obtained particles were mainly composed of the SiC phase, although Si and graphite phases remained mingled.

Droplet introduction into a pen-shaped portable reaction system by gravity and interfacial forces

A pen-shaped platform that is similar to a mechanical pencil was proposed for producing the portable biochemical reaction system presented in previous work. The key component, the sample introduction unit, in the system was proposed in this work. The unit was fabricated by using a heat shrinkable tube. The sample droplet with the volume ranging from 6 to 36 µl was successfully introduced into the unit by using the gravity force. The volume of the sample droplet could be expressed by the volume of the sample solution initially loaded into the tube, and the force equilibrium condition of the sample solution when the tube was perpendicular to the ground.

Design and evaluation of synthetic silica-based monolithic materials in shrinkable tube for efficient protein extraction

Sample pretreatment is a required step in proteomics in order to remove interferences and preconcentrate the samples. Much research in recent years has focused on porous monolithic materials since they are highly permeable to liquid flow and show high mass transport compared with more common packed beds. These features are due to the micro-structure within the monolithic silica column which contains both macropores that reduce the back pressure, and mesopores that give good interaction with analytes. The aim of this work was to fabricate a continuous porous silica monolithic rod inside a heat shrinkable tube and to compare this with the same material whose surface has been modified with a C(18) phase, in order to use them for preconcentration/extraction of proteins. The performance of the silica-based monolithic rod was evaluated using eight proteins; insulin, cytochrome C, lysozyme, myoglobin, β-lactoglobulin, ovalbumin, hemoglobin, and bovine serum albumin at a concentration of 60 μM. The results show that recovery of the proteins was achieved by both columns with variable yields; however, the C(18) modified silica monolith gave higher recoveries (92.7 to 109.7%) than the non-modified silica monolith (25.5 to 97.9%). Both silica monoliths can be used with very low back pressure indicating a promising approach for future fabrication of the silica monolith inside a microfluidic device for the extraction of proteins from biological media.

Characteristics of an optimized catheter-type thermal flow sensor for measuring reciprocating airflows in bronchial pathways

We optimized a catheter-type thermal flow sensor to measure the reciprocating airflows in bronchial pathways. The electrical wiring in the outer tube was extracted to keep the symmetry of the temperature distribution on the heaters. First, a flexible sensor was fabricated on polyimide film with photolithography, and then the enameled wires were bonded to the contact pads on the film with anisotropic conductive film. The film sensor was finally assembled with a catheter configuration that had a diameter of 1.8 mm by applying a heat shrinkable tube. We experimentally confirmed that the sensor outputs under both forward and reverse flow conditions had the same output characteristics when a design with symmetrical heating elements was applied. The sensor outputs we obtained at a reciprocating flow frequency ranging from 1 to 3 Hz almost coincided, and they also fit that obtained under unidirectional airflow conditions. Finally, the aspirated- and inspired-air characteristics in the air passages of small laboratory animals (rats and mice) were measured. Due to our development of a flexible method of electrical wiring, we could try a new approach to intubation measurements in which the sensor was inserted into the air passage from the mouth with a fiberscope, and we confirmed that the sensor we developed was able to directly measure the breathing characteristics in air passages. Implanted measurements were also attempted in this study.

Ground truth hardware phantoms for validation of diffusion‐weighted MRI applications

To quantitatively validate diffusion-weighted MRI (DW-MRI) applications, a hardware phantom containing crossing fibers at a sub-voxel level is presented. It is suitable for validation of a large spectrum of DW-MRI applications from acquisition to fiber tracking, which is an important recurrent issue in the field. Phantom properties were optimized to resemble properties of human white matter in terms of anisotropy, fractional anisotropy, and T(2). Sub-voxel crossings were constructed at angles of 30, 50, and 65 degrees, by wrapping polyester fibers, with a diameter close to axon diameter, into heat shrink tubes. We show our phantoms are suitable for the acquisition of DW-MRI data using a clinical protocol. The phantoms can be used to successfully estimate both the diffusion tensor and non-Gaussian diffusion models, and perform streamline fiber tracking. DOT (Diffusion Orientation Transform) and q-ball reconstruction of the diffusion profiles acquired at b = 3000 s/mm(2) and 132 diffusion directions reveal multimodal diffusion profiles in voxels containing crossing yarn strands. The highly purpose adaptable phantoms provide a DW-MRI validation platform: applications include optimisation of acquisition schemes, validation of non-Gaussian diffusion models, comparison and validation of fiber tracking algorithms, and quality control in multi-center DWI studies.

Fabrication of monolithically integrated flow sensor on tube

A monolithic-type flow sensor was developed to simplify the packaging process for microelectro mechanical system (MEMS) fluidic devices. In our design, a heater element for sensing flows as part of a thermal flow sensor was formed on the outside surface of a thin film in a tube, enabling us to connect electrical wiring from it to the outside of the tube directly. The monolithic-type flow sensor was produced by applying photolithography on a cylinder surface and transferring a cylindrical parylene film structure to the outside of the skeleton tube by using an adhesive heat-shrinkable tube. The relationship between the input power of the sensor and the flow rate obeyed King's equation under the flow conditions for 0–2000 sccm. The response time of 116 ms, which is comparable to that of commercially available mass flow controllers, was obtained.

Optical fiber arterial pulse wave sensor

AbstractAn optical fiber arterial pulse wave sensor is proposed using an in‐line Michelson interferometer that is a hollow optical fiber spliced to a single‐mode fiber at one end and cleaved at the other end. The proposed optical fiber arterial pulse wave sensor consists of an in‐line Michelson interferometer and steel reinforcement enclosed in a heat‐shrinkable tube. The sensor was directly attached onto a wrist and signals corresponding to arterial pulse waves successfully obtained. The signal‐to‐noise ratio of the sensor signals was better than 20 dB. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1318–1321, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25200

Ammonium detection by formation of colored zebra-bands in a detecting tube

Ammonium ion was colorized by means of a diazo coupling reaction with 2-phenylphenol, where the color development reaction was conducted within 3min by using boric acid as a catalyst. The resulting colored solution (0.5ml) was supplied by suction to a detecting tube consisting of a nonwoven fabric test strip (2mm wide, 1mm thick, 150mm long) impregnated with benzylcetyldimethylammonium chloride in a stripe pattern and enclosed in a heat-shrinkable tube. When the colored solution was supplied to the detecting tube, blue zebra-bands formed, and the ammonium concentration was determined by counting the number of zebra-bands. The detection range was 1-20mg-Nl(-1). Ammonium ion in actual domestic wastewater samples was successfully detected by means of this method.

A study of a MV cable joint

Construction parameters of a medium voltage (MV) cable joint were examined in order to reduce the electric field magnitude inside the joint. The joint was covered with a heat shrinkable tube made of two or three layers. The permittivity of the layers was varied. The termination angle of the cable dielectric was also considered.