Cage Construct Research Articles

Crystallization Mechanism of a Family of Embedded Isoreticular Zeolites

We have recently been successful in predicting and synthesizing a series of body-centered cubic zeolites with expanding structural complexity and embedded isoreticular structures, termed the RHO family. Here we propose a plausible formation pathway for ECR-18, ZSM-25, and PST-20, the three members of this zeolite family, in the presence of tetraethylammonium ions as an organic structure-directing agent, based on the 13C MAS NMR, IR, and CO2 adsorption results obtained from the solid products recovered as a function of time during their crystallization processes, together with the quantum-chemical calculation results. The nucleation of these three zeolites, all of which consist of seven different structural units, begins with the almost simultaneous construction of 26-hedral lta and 14-hedral t-plg cages and their subsequent connection via shared 8-rings in the diagonal direction of the cubic unit cell. As a logical next step, 8-hedral t-oto and 12-hedral t-phi cages are built around the preorganized t-plg cages. The remaining embedded spaces are readily filled up with 10-hedral t-gsm cages, as well as with t-oto and t-phi cages. Finally, 10-hedral d8r and 14-hedral pau cages are alternately constructed along the cubic edges. Over the outer surface of the resulting nuclei of the RHO family zeolites, the crystal growth may occur in a similar manner as described above.

Reversible Multistimuli Switching of a Spiropyran-Functionalized Organic Cage in Solid and Solution.

A spiropyran-decorated covalent organic cage (PC2) has been designed, employing dynamic imine chemistry followed by imine bond reduction. The molecule is capable of altering its color upon exposure to external stimuli such as heat and light. Construction of a 3D organic cage introduces a new piece to the system by swapping the closed form with the open form in the solid state with diverse color change. Moreover, this material has high chemical stability and is capable of reversible stimuli-responsive color change without any degradation for an extended period.

Vascularized Fibular Strut Autografts in Spinal Reconstruction after Resection of Vertebral Chordoma or Chondrosarcoma: A Retrospective Series.

Margin-free en bloc resection is the best medical practice for primary vertebral chordoma and chondrosarcoma. Spinal reconstruction following total spondylectomy requires reconstructive interbody graft (allograft, devascularized autograft, vascularized autograft, or cage constructs) and instrumentation. An important consideration when choosing grafts and instrumentation is the durability and the long-term success of the fusion without subsidence. To evaluate the potential use of vascularized fibular autograft as a reconstructive strategy after en bloc resection. We present a series of 16 patients who underwent spondylectomy for primary vertebral chordoma or chondrosarcoma with reconstruction using a vascularized fibular autograft and anterior/posterior instrumentation between January 2011 and April 2014. We report postoperative neurological outcome, 6-mo rates of fusion and graft subsidence, and other complications. Two patients passed away prior to 6-mo follow-up, and 1 patient was lost to follow-up. The mean follow-up time for the remaining 13 patients was 32 mo. Of these patients, 9 (69%) had evidence of fusion on the 6-mo follow-up computed tomography (CT) scan. Of the 4 patients who did not fuse, 2 had undergone surgery for new tumor diagnoses, 1 for hardware failure, and 1 for graft nonunion. Two patients (15%) had eventual graft subsidence along with hardware failure. Vascularized fibular strut grafts are a viable method for reconstruction following spondylectomy. We present the largest series of patients to date utilizing this technique. Further comparative studies examining vascularized grafts vs nonvascularized grafts or metallic cage constructs will be important in choosing the best reconstructive strategy.

The model of double-cage induction motor for the analysis of thermal fields in transient operations

AbstractEmergency motor switch-on happens occasionally while operating a doublesquirrel- cage motor at full supply voltage with the rotor blocked (e.g., in coal mills). After releasing the blockage, the by now heated motor is started up again. However, the mechanical stress caused by the increased temperature poses considerable hazards to the squirrel-cage winding. This paper presents a double-cage induction motor model for analysis of thermal fields in transient operation. The thermal field for the rotor of a doublesquirrel- cage motor of soldered or cast structure, operating in the conditions described, has been calculated in the present paper using a thermal network method. Measurement results have been presented for the double-squirrel-cage winding temperature for a soldered cage construction in the blocked rotor state.

Crystallization Mechanism of Cage-Based, Small-Pore Molecular Sieves: A Case Study of CHA and LEV Structures

Here we have investigated the crystallization mechanisms of SSZ-13 and SAPO-34 with the CHA topology and NU-3 and SAPO-35 with the LEV topology using 1H–13C CP MAS NMR and IR spectroscopies. The nucleation of these cage-based, small-pore molecular sieves begins with the formation of large 20-hedral cha or 17-hedral lev cages, with incorporation of organic structure-directing agents (SDAs) alone or together with inorganic cations, in both aluminosilicate and silicoaluminophosphate compositions. The next two steps are the construction of multiple-cha or multiple-lev cages in an appropriate arrangement by sharing 8-rings and their subsequent coupling to form smaller 8-hedral double 6-ring units, leading to viable nuclei of CHA or LEV molecular sieves. The initial formation of the large cages, especially in the presence of large SDA molecules, can in our view be generalized to other cage-based zeolite systems.

An engineered home environment for untethered data telemetry from nonhuman primates

BackgroundWireless neural recording technologies now provide untethered access to large populations of neurons in the nonhuman primate brain. Such technologies enable long-term, continuous interrogation of neural circuits and importantly open the door for chronic neurorehabilitation platforms. For example, by providing continuous consistent closed loop feedback from a brain machine interface, the nervous system can leverage plasticity to integrate more effectively into the system than would be possible in short experimental sessions. However, to fully realize this opportunity necessitates the development of experimental environments that do not hinder wireless data transmission. Traditional nonhuman primate metal cage construction, while durable and standardized around the world, prevents data transmission at the frequencies necessary for high-bandwidth data transfer. New methodTo overcome this limitation, we have engineered and constructed a radio-frequency transparent home environment for nonhuman primates using primarily non-conductive materials. ResultsComputational modeling and empirical testing were performed to demonstrate the behavior of transmitted signals passing through the enclosure. In addition, neural data were successfully recorded from a freely behaving nonhuman primate inside the housing system. Comparison with existing methodsOur design outperforms standard metallic home cages by allowing radiation to transmit beyond its boundaries, without significant interference, while simultaneously maintaining the mechanical and operational integrity of existing commercial home cages. ConclusionsContinuous access to neural signals in combination with other bio-potential and kinematic sensors will empower new insights into unrestrained behavior, aid the development of advanced neural prostheses, and enable neurorehabilitation strategies to be employed outside traditional environments.

Establishing, Expanding, and Certifying a Closed Colony of Phlebotomus argentipes (Diptera: Psychodidae) for Xenodiagnostic Studies at the Kala Azar Medical Research Center, Muzaffarpur, Bihar, India.

This pilot project was preliminary and essential to a larger effort to define the ability of certain human-subject groups across the infection spectrum to serve as reservoirs of Leishmania donovani infection to sand flies in areas of anthroponotic transmission such as in Bihar state, India. This is possible only via xenodiagnosis of well-defined subject groups using live vector sand flies. The objective was to establish at the Kala Azar Medical Research Center (KAMRC), Muzaffarpur, Bihar, India, a self-sustaining colony of Phlebotomus argentipes (Annandale & Brunneti), closed to infusion with wild-caught material and certified safe for human xenodiagnosis. Prior to this endeavor, no laboratory colony of this vector existed in India meeting the stringent biosafety requirements of this human-use study. From March through mid-December, 2015, over 68,000 sand flies were collected in human dwellings and cattle sheds using CDC-type light traps over 254 nights. Blood-fed and gravid P. argentipes females were selected and placed individually in isoline-rearing vials for oviposition, and >2,500 egg clutches were harvested. Progeny were reared according to standard methods, providing a continuous critical mass of F1 males and females to stimulate social feeding behavior. With construction of a large feeding cage and use of a custom-made rabbit restrainer, the desired level of blood-feeding on restrained rabbits was achieved to make the colony self-sustaining and expand it to working level. Once self-sustaining, the colony was closed to infusion with wild-caught material and certified free of specific human pathogens.

"Steel-Concrete" Inspired Biofunctional Layered Hybrid Cage for Spine Fusion and Segmental Bone Reconstruction.

In this paper we report a "steel-concrete" inspired layered hybrid spine cage combining a titanium mesh and a bioceramic scaffold, which were welded together through a bioglass bonding layer using a novel multistep manufacturing methodology including three-dimensional slip deposition, gel casting, freeze-drying, and cosintering. The interfacial welding strength achieved 27 ± 0.7 MPa, indicating an excellent structural integrity of the hybrid cage construct. The biocramic scaffold layer consisting of wollastonite and hydroxyapatite had an interconnected, highly porous structure with a pore size of 100-500 μm and a porosity of >85%, well fufilling the structural requirements of bone regeneration. Simulated body fluid immersion assay showed that the hybrid cage exhibited excellent biodegradability to facilitate rapid bone-like apatite formation. In vitro studies demonstrated that the bioceramic scaffold on the hybrid cage supported attachment, spreading, growth, and migration of bone/vessel-forming cells and triggered osteogenic differentiation of human mesenchymal stem cells. In vivo studies further suggested that the bioceramic scaffold on the hybrid cage could actively promote fast generation of new bone tissues within 12 weeks of implantation in a rabbit femoral condyle model. This study has provided a new design and fabrication methodology of hybrid cages by integrating strong mechanical properties with excellent biological activities including osteoinductivity and bone regeneration ability, for spine fusion and segmental bone reconstruction.

A cell attracting composite of lumbar fusion cage

Lumbar fusion cages are devices used in spinal fusion procedures for disorders such as spondylosis and degenerative disc diseases that may occur due to age, trauma or genetic reasons. These devices are most frequently made of metals and polymers. The mechanical properties of such devices should be comparable to the bone to avoid stress shielding. Besides, cages should interact with the cells to prevent extrusion and achieve satisfactory fusion. In this study, poly(methylmethacrylate) (PMMA) and hydroxyapatite (HAp) were compounded to create products with HAp contents up to 40% (w/w), processed by hot melt extrusion and injection molded to produce composites with maximum polymer-mineral interaction. The morphology, interaction with the plates and rate of proliferation of human osteoblast-like (HOB) cells were studied in vitro. We learned that cells interact more with HAp when the HAp content is higher than 20%. Tensile and compressive properties of PMMA were significantly increased with increasing HAp content; from an elastic modulus (E) of 2.08 to 3.92 GPa in tension, and from 349 to 562 MPa in compression. High HAp content of the samples increased the roughness from 0.69 μm for pure PMMA to 1.35 μm for 40% (w/w) HAp loaded PMMA, increased cell proliferation and as a result the cells presented filopodia indicating a satisfactory level of interaction with the cage surface. Based on mechanical and in vitro studies, a HAp content of around 30% (w/w) was found to be appropriate for good cell adhesion and satisfactory mechanical properties for use in the construction of a fusion cage. It was concluded that when PMMA and HAp were compounded at an optimal value, a cage material with adequate mechanical properties and increased cell attachment can be obtained for use in spinal fusion applications.

Designand Implementation of Networked Control SystemviaEthernetforSelf Excited Induction Generator Using OPC Server

Induction generators are increasingly being used in nonconventional energy systems such as wind, micro/mini hydro, etc. The advantages of using an induction generator instead of a synchronous generator are well known. Some of them are reduced unit cost and size, ruggedness, brushless (in squirrel cage construction), absence of separate dc source, ease of maintenance, self-protection against severe overloads and short circuits, etc. In isolated systems, squirrel cage induction generators with capacitor excitation, known as self-excited induction generators (SEIGs), are very popular. Remotely control applications over a wide area had been commonly used in the industries today. One of the common applications requires remote control and monitoring is output voltage control of SEIGs supplied insensitive frequency loads. Drive system has various types of controller, in order to perform some actions such as control the speed to control the output voltage of SEIGs, switching On or Off loads supplied by the generator. This control system can be done by Programmable Logic Controller (PLC), and with the rise of the technology, Ethernet module will be used in order to achieve the remotecontrol system. Plus the PLC today can be controlled not only using its original software, but 3rd party software as well, such as LabVIEW). LabVIEW is a human machine interfaces design software that is user friendly. It can be easily communicate with different hardware using OLE for Process Control (OPC) server.

Anterior Lumbar Interbody Fusion Integrated Screw Cages: Intrinsic Load Generation, Subsidence, and Torsional Stability.

To perform a repeatable idealized in vitro model to evaluate the effects of key design features and integrated screw fixation on unloaded surface engagement, subsidence, and torsional stability. We evaluated four different stand-alone anterior lumbar interbody fusion (ALIF) cages with two, three, and four screw designs. Polyurethane (saw-bone) foam blocks were used to simulate the vertebral bone. Fuji Film was used to measure the contact footprint, average pressure, and load generated by fixating the cages with screws. Subsidence was tested by axially loading the constructs at 10 N/s to 400 N and torsional load was applied +/-1 Nm for 10 cycles to assess stability. Outcome measures included total subsidence and maximal torsional angle range. Cages 1, 2, and 4 were symmetrical and produced similar results in terms of contact footprint, average pressure, and load. The addition of integrated screws into the cage-bone block construct demonstrated a clear trend towards decreased subsidence. Cage 2 with surface titanium angled ridges and a keel produced the greatest subsidence with and without screws, significantly more than all other cages ( P < 0.05). Angular rotation was not significantly affected by the addition of screws ( P < 0.066). A statistically significant correlation existed between subsidence and reduced angular rotation across all cage constructs ( P = 0.018). Each stand-alone cage featured unique surface characteristics, which resulted in differing cage-foam interface engagement, influencing the subsidence and torsional angle. Increased subsidence significantly reduced the torsional angle across all cage constructs.

Biomechanics of an Expandable Lumbar Interbody Fusion Cage Deployed Through Transforaminal Approach.

A novel expandable lumbar interbody fusion cage has been developed which allows for a broad endplate footprint similar to an anterior lumbar interbody fusion (ALIF); however, it is deployed from a minimally invasive transforaminal unilateral approach. The perceived benefit is a stable circumferential fusion from a single approach that maintains the anterior tension band of the anterior longitudinal ligament.The purpose of this biomechanics laboratory study was to evaluate the biomechanical stability of an expandable lumbar interbody cage inserted using a transforaminal approach and deployed in situ compared to a traditional lumbar interbody cage inserted using an anterior approach (control device). Twelve cadaveric spine specimens (L1-L5) were tested intact and after implantation of both the control and experimental devices in two (L2-L3 and L3-L4) segments of each specimen; the assignments of the control and experimental devices to these segments were alternated. Effect of supplemental pedicle screw-rod stabilization was also assessed. Moments were applied to the specimens in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). The effect of physiologic preload on construct stability was evaluated in FE. Segmental motions were measured using an optoelectronic motion measurement system. The deployable expendable TLIF cage and control devices significantly reduced FE motion with and without compressive preload when compared to the intact condition (p<0.05). Segmental motions in LB and AR were also significantly reduced with both devices (p<0.05). Under no preload, the deployable expendable TLIF cage construct resulted in significantly smaller FE motion compared to the control cage construct (p<0.01). Under all other testing modes (FE under 400N preload, LB, and AR) the postoperative motions of the two constructs did not differ statistically (p>0.05). Adding bilateral pedicle screws resulted in further reduction of ROM for all loading modes compared to intact condition, with no statistical difference between the two constructs (p>0.05). The ability of the deployable expendable interbody cage in reducing segmental motions was equivalent to the control cage when used as a stand-alone construct and also when supplemented with bilateral pedicle screw-rod instrumentation. The larger footprint of the fully deployed TLIF cage combined with preservation of the anterior soft-tissue tension band may provide a better biomechanical fusion environment by combining the advantages of the traditional ALIF and TLIF approaches.

サブコンポーネントの自己組織化を利用した機能性分子ケージの構築

This article describes the recent research on molecular cages achieved in Nitschkeʼs group. Subcomponent self-assembly allows the construction of molecular cages from simple building blocks via the formation of coordination bonds and dynamic covalent bonds around metal templates. By utilizing this method, a variety of functional molecular cages have been constructed. In this article, we focused on two topics. In the first topic, molecular cages were utilized for the molecular recognition and the catalytic reaction. In the second topic, we describe the interesting nature of molecular cages that originates from reversible substitution of subcomponents of molecular cages.

Formation of cyclopentane - methane hydrates in brine systems and characteristics of dissolved ions

Based on the hot brine in situ seafloor prepared for marine NGHs exploitation, the formation of hydrates and the characteristics of dissolved ions were investigated for the cyclopentane (CP)-methane-NaCl solution (3.5%) system. Both the gas consumption and the solution salinity influenced by two factors – the flow rate of gas (Qg) and the mass fraction of CP (MCP) -were discussed. On one hand, the gas consumption went up at a lower MCP (3.950wt%) while dropped down at a higher MCP (8.340 or 18.775wt%) with the increase of Qg. Nevertheless, higher mass fraction of CP behaved more favorable for the gas consumption. On the other hand, there would be a similar trend that the salinity of remaining liquid increased firstly and then decreased with the reaction time at any fixed Qg and MCP, which might be attributed to the adsorption of Na+ and Cl− on the surface of hydrate. Furthermore, PXRD analysis of the hydrate was conducted to confirm this explanation. And it was confirmed that the ion of Na+ or Cl− did not play any role in the construction of hydrate cages. Meanwhile, CP was enclosed in large cavities (51264) while CH4 was mainly enclosed in the small cavities (512).

Reconstructing Pelvic Discontinuity and Severe Acetabular Bone Loss in Revision Hip Arthroplasty with a Massive Allograft and Cage.

The use of a massive allograft along with an antiprotrusio cage for the treatment of large periprosthetic acetabular defects can restore structural integrity to the pelvis and provide durable revision-free survival. Perform an extensile approach to the acetabulum. Ensure that the appropriate tools are available for removal of the existing acetabular component. It is important to remove fibrous tissue around the acetabulum to get to healthy bleeding bone. It is important to remove all of the native cartilage from the graft to allow for osseous ingrowth potential. Ensure that the graft properly fits within the acetabular defect. It is important to stabilize the bulk allograft to the pelvis before reaming. Impact the cage implant into position and secure it to the pelvis with as many screws as necessary to obtain a secure implant. Cement the polyethylene cup in the proper orientation and reduce the hip. We reviewed 72 cage constructs in 68 patients at a mean follow-up of 5.1 years (range, 1.2 to 10.7 years)3.

Decoration of the Truncated Tetrahedron—An Archimedean Polyhedron—To Produce a New Class of Convex Equilateral Polyhedra with Tetrahedral Symmetry

The Goldberg construction of symmetric cages involves pasting a patch cut out of a regular tiling onto the faces of a Platonic host polyhedron, resulting in a cage with the same symmetry as the host. For example, cutting equilateral triangular patches from a 6.6.6 tiling of hexagons and pasting them onto the full triangular faces of an icosahedron produces icosahedral fullerene cages. Here we show that pasting cutouts from a 6.6.6 tiling onto the full hexagonal and triangular faces of an Archimedean host polyhedron, the truncated tetrahedron, produces two series of tetrahedral (Td) fullerene cages. Cages in the first series have 28n2 vertices (n ≥ 1). Cages in the second (leapfrog) series have 3 × 28n2. We can transform all of the cages of the first series and the smallest cage of the second series into geometrically convex equilateral polyhedra. With tetrahedral (Td) symmetry, these new polyhedra constitute a new class of “convex equilateral polyhedra with polyhedral symmetry”. We also show that none of the other Archimedean polyhedra, six with octahedral symmetry and six with icosahedral, can host full-face cutouts from regular tilings to produce cages with the host’s polyhedral symmetry.

Observation on Forces and Motions of a Mariculture Cage From Model and Prototype Experiments

In India, several experimental coastal aquaculture cages have been installed on sites along the Indian coast. Many of them have been commercially successful, while some have faced technical difficulties. The construction of the Indian coastal aquaculture cage is based on ad hoc designs adopted from other countries. The performance of the coastal aquaculture cage shows that there is a need for development of a cage design with a location-specific mooring system to withstand local wave conditions for a longer period in different coastal zones of the country. This requires that designs of the cages suiting Indian conditions be made based on sound engineering principles. To design the cage, the current- and wave-induced tensions in the mooring chain and net twine and the cage motions need to be estimated. In this study, a model cage was fabricated and tested in a towing tank under different waves and towing conditions. The tension on the mooring chain was measured during model experiments along with the towing speed and wave parameter. A prototype coastal aquaculture cage with single point mooring near the coast of Visakhapatnam in South East India was identified for measurement of forces and motions. On the prototype cage, measurements of cage motions, tensions on mooring chain, and net twine and cage orientation were carried out. Characteristics of the cage response, observed in model and prototype experiments, are presented in this paper. The model cage is not a geometrically scaled down version of the prototype cage. The diameter/depth ratios of the model and the prototype are different. The mooring pattern and net twine of the model cage is the same as that of the prototype. The data presented in this paper could be used as a reference for validating the numerical model for simulating the cage forces and motions under wave and current loads.

Exposure of the superior gluteal neurovascular bundle for the safe application of acetabular reinforcement cages in complex revisions.

The posterior approach to the hip is the most common extensile approach used, however exposure is limited superiorly by the superior gluteal neurovascular bundle (SGNB). The extra-pelvic course of the SGNB demonstrates variability between individuals, occasionally located only 1 cm from the acetabular rim. In complex acetabular reconstructions where the application of a reinforcement cage maybe required protecting the SGNB is challenging. The flanges of these cages are designed to sit on the ilium superior to the acetabular rim and to receive screws for fixation. The application of such cages may result in iatrogenic injury to the SGNB by way of forceful retraction or entrapment. We describe a technique that involves exposure and release of the SGNB such that the flanges of cage constructs may be safely applied.

Cartilage Tissue Engineering: Preventing Tissue Scaffold Contraction Using a 3D-Printed Polymeric Cage.

Scaffold contraction is a common but underestimated problem in the field of tissue engineering. It becomes particularly problematic when creating anatomically complex shapes such as the ear. The aim of this study was to develop a contraction-free biocompatible scaffold construct for ear cartilage tissue engineering. To address this aim, we used three constructs: (i) a fibrin/hyaluronic acid (FB/HA) hydrogel, (ii) a FB/HA hydrogel combined with a collagen I/III scaffold, and (iii) a cage construct containing (ii) surrounded by a 3D-printed poly-ɛ-caprolactone mold. A wide range of different cell types were tested within these constructs, including chondrocytes, perichondrocytes, adipose-derived mesenchymal stem cells, and their combinations. After in vitro culturing for 1, 14, and 28 days, all constructs were analyzed. Macroscopic observation showed severe contraction of the cell-seeded hydrogel (i). This could be prevented, in part, by combining the hydrogel with the collagen scaffold (ii) and prevented in total using the 3D-printed cage construct (iii). (Immuno)histological analysis, multiphoton laser scanning microscopy, and biomechanical analysis showed extracellular matrix deposition and increased Young's modulus and thereby the feasibility of ear cartilage engineering. These results demonstrated that the 3D-printed cage construct is an adequate model for contraction-free ear cartilage engineering using a range of cell combinations.

Compressed Column Strengthening by Holder Constructions with the Use of a Self-consolidating Fiber Concrete

The problems of increasing in the bearing ability of reinforced concrete columns during reconstruction of buildings and structures of a different function are still rather acute. There are conditions of innovative material emergence in construction and a need for development of new constructive solutions for strengthening of the bearing designs.The paper presents some results of experimental research influence by the kind of concrete in cage constructions on the strength and deformability of concrete compressed elements.