Shape Of Cages Research Articles

UPAYA PENINGKATAN PRODUKTIFITAS PEMBUATAN SANGKAR BURUNG BERBASIS ROTAN KETIKA MUSIM HUJAN

A group of young people from Jegrik village, Karanganyar district, have a business making bird cages. The shape of bird cages they make are oval-shaped bird cages, which are used to cage turtle doves, puter birds, and turtle doves. Making bird cages using rattan as raw material. With the technology developed in the form of a blengker mal tool that utilizes the heat propagation of fire, this tool is a solution to the problems that occur during the rainy season, where heat from the sun is needed to make the blengker, but often there is no sunlight, which hampers production. It's different when during the dry season the heat of the sun is used to make blengker. Problems during the rainy season can be overcome with heating devices that utilize a heat propagation system from a flame that spreads its heat to the walls of the device. The heat comes from the flame from the LPG gas stove. To make a blengker, it only takes approximately 7 minutes, the heat on the walls of the blender is approximately 40oC-70oC.

Tide-induced changes in marine fish cage-shape cause changes in swimming behavior of cultured chub mackerel (Scomber japonicus)

We performed field measurements of the behavioral changes in cultured chub mackerel (Scomber japonicus) caused by tide-induced changes in the shapes of their small-sized tetragonal fish cages. The field measurements were conducted in two separate periods: neap tide, a period in which the shape of the fish cages was stable; and spring tide, a period in which the fish cages are significantly deformed, which was expected to have significant influences on fish behavior. In the spring tide, the cages were deformed greatly by the moving water, with different water velocities affecting the cages to different degrees; the volume loss was estimated at 4.9% and 7.3% for v = 0.114 m/s and v = 0.221 m/s, respectively. The fish exhibited significantly different behaviors between the neap tide and spring tide. During the neap tide, the fish remained in the lower part of the cage, but during the spring tide they made frequent upward and downward movements, and their horizontal distribution changed significantly due to the changes in the shape of the cage. The cage deformation during the spring tide greatly influenced the swimming behavior of fish.

Highly tumor-specific DNA nanostructures discovered by in vivo screening of a nucleic acid cage library and their applications in tumor-targeted drug delivery

Enormous efforts have been made to harness nanoparticles showing extravasation around tumors for tumor-targeted drug carriers. Owing to the complexity of in vivo environments, however, it is very difficult to rationally design a nanoconstruct showing high tumor specificity. Here, we show an approach to develop tumor-specific drug carriers by screening a library of self-assembled nucleic acid cages in vivo. After preparation of a library of 16 nucleic acid cages by combining the sugar backbone and the shape of cages, we screened the biodistribution of the cages intravenously injected into tumor-bearing mice, to discover the cages with high tumor-specificity. This tumor specificity was found to be closely related with serum stability, cancer cell uptake efficiency, and macrophage evasion rate. We further utilized the cages showing high tumor specificity as carriers for the delivery of not only a cytotoxic small molecule drug but also a macromolecular apoptotic protein exclusively into the tumor tissue to induce tumor-specific damage. The results demonstrate that our library-based strategy to discover tumor-targeted carriers can be an efficient way to develop anti-cancer nanomedicines with tumor specificity and enhanced potency.

Halide encapsulation by dicarboxylate oxido-vanadium cage complexes.

Compounds [Bu4N]2[V8O16(oda)4⊂2Cl], 1, [Bu4N]2[V8O16(glut)4⊂2Cl], 2, and [Bu4N][V4O8(glut)2⊂F], 3, (oda = oxydiacetate, O(CH2COO)22-; glut = glutarate, CH2(CH2COO)22-) were obtained by a stepwise reaction of in situ prepared [Bu4N]VO3 with HCl (or HF for 3) and then with the dicarboxylic acid X(CH2COOH)2 (X = O and CH2), under appropriate reaction conditions. Multinuclear magnetic resonance (1H, 13C{1H}, 35Cl, 19F and 51V), electrochemical studies, X-ray structural determinations (single crystal and powder), thermogravimetric analyses (TGA) and Density Functional Theory (DFT) calculations were employed to characterise these polyoxovanadate complexes 1-3. They included encapsulated halide anions, two chloride ions in 1 and 2 and one fluoride ion in 3, where the shape and dimensions of the cage were governed by the halide size. The stabilizing template effect of the chloride ion towards the bowl-shaped [V4O8(OOCR)4] fragment (i.e. the half part of 1 and 2), containing a crown-shaped {V4O8} subunit, or that of the fluoride ion towards the planar {V4O8} moiety in 3, was definitively demonstrated by DFT calculations. The HOMO composition of 1 prompted us to study the possible oxidation of the two encapsulated chloride ions toward a chlorine molecule. The electrochemical behaviors of 1-3 were thus investigated. However, the chlorine molecule in the model [V8O16(oda)4⊂(Cl2)], 6c, was not capable to stabilise the polyoxovanadate cage [V8O16(oda)4], 4c, according to DFT calculations.

Low incidence of adjacent segment disease after posterior lumbar interbody fusion with minimum disc distraction: A preliminary report.

Study Design:A retrospective review of prospectively collected data.Objective:To investigate the incidence of radiographic and symptomatic adjacent segment disease (ASD) and identify possible risk factors for ASD after posterior lumbar interbody fusion (PLIF) with minimum disc distraction by selecting low-height interbody cages.Summary of Background Data:Excessive disc space distraction is reportedly 1 of the risk factors for ASD after PLIF; however, the incidence and other risk factors of ASD after PLIF with minimum disc distraction remain unclear.Methods:Forty-one consecutive patients who underwent PLIF at L4-L5 and were postoperatively followed up for a minimum of 2 years were included. The height and shape (box or bullet shape) of interbody cages was determined according to the disc height and morphology of the intervertebral space assessed on preoperative computed tomography scans to avoid excessive distraction. The incidence of radiographic and symptomatic ASD was evaluated and all demographic and radiographic parameters were compared between patients with and without ASD. Multivariate logistic regression analysis was performed to identify risk factors for ASD among the variables with P < .20 in univariate analysis.Results:The overall incidence of ASD was 12.2% (5/41 patients): radiographic ASD, 7.3% (3 patients); symptomatic ASD, 4.9% (2 patients). Multivariate analysis revealed preoperative retrolisthesis of L3 on extension as the sole risk factor for ASD after PLIF with minimum disc distraction (odds ratio, 2.13; 95% confidence interval, 1.00–4.05; P = .049).Conclusions:The incidence of ASD in this study was lower than that of ASD in our previous study about PLIF with distraction of disc space (12.2% vs. 31.8%). Minimum disc distraction by selection of low-height interbody cages is a simple and effective method to prevent ASD at the surgeons’ discretion, although preexisting retrolisthesis at the adjacent upper segment should be taken into consideration.

Biomechanical investigation into the structural design of porous additive manufactured cages using numerical and experimental approaches

Traditional solid cages have been widely used in posterior lumbar interbody fusion (PLIF) surgery. However, solid cages significantly affect the loading mechanism of the human spine due to their extremely high structural stiffness. Previous studies proposed and investigated porous additive manufactured (AM) cages; however, their biomechanical performances were analyzed using oversimplified bone-implant numerical models. Thus, the aim of this study was to investigate the outer shape and inner porous structure of the AM cages. The outer shape of the AM cages was discovered using a simulation-based genetic algorithm; their inner porous structure was subsequently analyzed parametrically using T10-S1 multilevel spine models. Finally, six types of the AM cages, which were manufactured using selective laser melting, were tested to validate the numerical outcomes. The subsidence resistance of the optimum design was superior to the conventional cage designs. A porous AM cage with a pillar diameter of 0.4mm, a pillar angle of 40°, and a porosity of between 69% and 80% revealed better biomechanical performances. Both the numerical and experimental outcomes can help surgeons to understand the biomechanics of PLIF surgery combined with the use of AM cages.

Variation and decomposition of the partial molar volume of small gas molecules in different organic solvents derived from molecular dynamics simulations

The partial molar volumes, V(i), of the gas solutes H2, CO, and CO2, solvated in acetone, methanol, heptane, and diethylether are determined computationally in the limit of infinite dilution and standard conditions. Solutions are described with molecular dynamics simulations in combination with the OPLS-aa force field for solvents and customized force field for solutes. V(i) is determined with the direct method, while the composition of V(i) is studied with Kirkwood-Buff integrals (KBIs). Subsequently, the amount of unoccupied space and size of pre-formed cavities in pure solvents is determined. Additionally, the shape of individual solvent cages is analyzed. Calculated V(i) deviate only 3.4 cm(3) mol(-1) (7.1%) from experimental literature values. Experimental V(i) variations across solutions are reproduced qualitatively and also quantitatively in most cases. The KBI analysis identifies differences in solute induced solvent reorganization in the immediate vicinity of H2 (<0.7 nm) and solvent reorganization up to the third solvation shell of CO and CO2 (<1.6 nm) as the origin of V(i) variations. In all solutions, larger V(i) are found in solvents that exhibit weak internal interactions, low cohesive energy density and large compressibility. Weak internal interactions facilitate solvent displacement by thermal solute movement, which enhances the size of solvent cages and thus V(i). Additionally, attractive electrostatic interactions of CO2 and the solvents, which do not depend on internal solvent interactions only, partially reversed the V(i) trends observed in H2 and CO solutions where electrostatic interactions with the solvents are absent. More empty space and larger pre-formed cavities are found in solvents with weak internal interactions, however, no evidence is found that solutes in any considered solvent are accommodated in pre-formed cavities. Individual solvent cages are found to be elongated in the negative direction of solute movement. This wake behind the moving solute is more pronounced in case of mobile H2 and in solvents with weaker internal interactions. However, deviations from a spherical solvent cage shape do not influence solute-solvent radial distribution functions after averaging over all solvent cage orientations and hence do not change V(i). Overall, the applied methodology reproduces V(i) and its variations reliably and the used V(i) decompositions identify the underlying reasons behind observed V(i) variations.

Prediction of Clathrate Structure Type and Guest Position by Molecular Mechanics

The clathrate hydrates occur in various types in which the number, size, and shape of the various cages differ. Usually the clathrate type of a specific guest is predicted by the size and shape of the molecular guest. We have developed a methodology to determine the clathrate type employing molecular mechanics with the MMFF force field employing a strategy to calculate the energy of formation of the clathrate from the sum of the guest/cage energies. The clathrate type with the most negative (most stable) energy of formation would be the type predicted (we mainly focused on type I, type II, or bromine type). This strategy allows for a calculation to predict the clathrate type for any cage guest in a few minutes on a laptop computer. It proved successful in predicting the clathrate structure for 46 out of 47 guest molecules. The molecular mechanics calculations also provide a prediction of the guest position within the cage and clathrate structure. These predictions are generally consistent with the X-ray and neutron diffraction studies. By supplementing the diffraction study with molecular mechanics, we gain a more detailed insight regarding the details of the structure. We have also compared MM calculations to studies of the multiple occupancy of the cages. Finally, we present a density functional calculation that demonstrates that the inside of the clathrates cages have a relatively uniform and low electrostatic potential in comparison with the outside oxygen and hydrogen atoms. This implies that van der Waals forces will usually be dominant in the guest-cage interactions.

Effect of small cage guests on hydrogen bonding of tetrahydrofuran in binary structure II clathrate hydrates

Molecular dynamics simulations of the pure structure II tetrahydrofuran clathrate hydrate and binary structure II tetrahydrofuran clathrate hydrate with CO(2), CH(4), H(2)S, and Xe small cage guests are performed to study the effect of the shape, size, and intermolecular forces of the small cages guests on the structure and dynamics of the hydrate. The simulations show that the number and nature of the guest in the small cage affects the probability of hydrogen bonding of the tetrahydrofuran guest with the large cage water molecules. The effect on hydrogen bonding of tetrahydrofuran occurs despite the fact that the guests in the small cage do not themselves form hydrogen bonds with water. These results indicate that nearest neighbour guest-guest interactions (mediated through the water lattice framework) can affect the clathrate structure and stability. The implications of these subtle small guest effects on clathrate hydrate stability are discussed.

Hydrogen trapped in Ben cluster cages: The atomic encapsulation option

Core–shell (kH)@Ben (k=1–3, n=6–11) systems are studied computationally. The smallest system with endohedral hydrogen is H@Be6 with a central H anion, thermodynamically stable to dissociation into H+Be6. Larger structures are constructed by merging a few such units and have reduced stability. Potential energy barriers to hydrogen exit from the cage assemblies are estimated. Face- and edge-sharing combinations of the structural units are considered. The extrapolated upper bound for the potential ‘nanofoam’ material storage capacity is 10weight-% of hydrogen. The changes in shape and electronic properties of the Ben cages upon insertion of hydrogen are also analyzed.

Encapsulation of small magnetic clusters in fullerene cages: A density functional theory investigation within van der Waals corrections

The encapsulation of magnetic transition-metal (TM) clusters inside carbon cages (fullerenes, nanotubes) has been of great interest due to the wide range of applications, which spread from medical sensors in magnetic resonance imaging to photonic crystals. Several theoretical studies have been reported; however, our atomistic understanding of the physical properties of encapsulated magnetic TM $3d$ clusters is far from satisfactory. In this work, we will report general trends, derived from density functional theory within the generalized gradient approximation proposed by Perdew, Burke, and Ernzerhof (PBE), for the encapsulation properties of the TM${}_{m}$@C${}_{n}$ (TM $=$ Fe, Co, Ni; $m=2\ensuremath{-}6$, $n=60,70,80,90$) systems. Furthermore, to understand the role of the van der Waals corrections to the physical properties, we employed the empirical Grimme's correction ($\mathrm{PBE}+\mathrm{D}2$). We found that both PBE and $\mathrm{PBE}+\mathrm{D}2$ functionals yield almost the same geometric parameters, magnetic and electronic properties, however, $\mathrm{PBE}+\mathrm{D}2$ strongly enhances the encapsulation energy. We found that the center of mass of the TM${}_{m}$ clusters is displaced towards the inside C${}_{n}$ surfaces, except for large TM${}_{m}$ clusters ($m=5$ and 6). For few cases, e.g., Co${}_{4}$ and Fe${}_{4}$, the encapsulation changes the putative lowest-energy structure compared to the isolated TM${}_{m}$ clusters. We identified few physical parameters that play an important role in the sign and magnitude of the encapsulation energy, namely, cluster size, fullerene equatorial diameter, shape, curvature of the inside C${}_{n}$ surface, number of TM atoms that bind directly to the inside C${}_{n}$ surface, and the van der Waals correction. The total magnetic moment of encapsulated TM${}_{m}$ clusters decreases compared with the isolated TM${}_{m}$ clusters, which is expected due to the hybridization of the $d\ensuremath{-}p$ states, and strongly depends on the size and shape of the fullerene cages.

3D reconstruction of the human rib cage from 2D projection images using a statistical shape model

This paper describes an approach for the three-dimensional (3D) shape and pose reconstruction of the human rib cage from few segmented two-dimensional (2D) projection images. Our work is aimed at supporting temporal subtraction techniques of subsequently acquired radiographs by establishing a method for the assessment of pose differences in sequences of chest radiographs of the same patient. The reconstruction method is based on a 3D statistical shape model (SSM) of the rib cage, which is adapted to binary 2D projection images of an individual rib cage. To drive the adaptation we minimize a distance measure that quantifies the dissimilarities between 2D projections of the 3D SSM and the projection images of the individual rib cage. We propose different silhouette-based distance measures and evaluate their suitability for the adaptation of the SSM to the projection images. An evaluation was performed on 29 sets of biplanar binary images (posterior-anterior and lateral). Depending on the chosen distance measure, our experiments on the combined reconstruction of shape and pose of the rib cages yield reconstruction errors from 2.2 to 4.7 mm average mean 3D surface distance. Given a geometry of an individual rib cage, the rotational errors for the pose reconstruction range from 0.1 degrees to 0.9 degrees. The results show that our method is suitable for the estimation of pose differences of the human rib cage in binary projection images. Thus, it is able to provide crucial 3D information for registration during the generation of 2D subtraction images.

Dynamic pathway model for the formation of C(60).

We present a dynamic pathway model for the formation of C(60) using the action-derived molecular dynamics simulations. We propose candidate precursors for dynamic pathway models in which carbons spontaneously aggregate due to favorable energetics and kinetics. Various planar polycyclic models are in a disadvantageous state where they cannot be trapped in the forward reaction due to their high excess internal energies. Our simulation results show that precursors either in the shape of tangled polycyclics or in the shape of open cages are kinetically favored over precursors in the shape of planar hexagonal graphite fragments. Calculated activation energies for the probable precursor models are in good agreement with experiment. Existence of chains in the models of tangled polycyclics and open cages is beneficially for the formation of C(60) molecule. Chains attached to the precursor model are energetically favorable and display lithe movements along the dynamic pathway.

Fullerenes with symmetrically arranged defects: Geometry and electronic structure

Recently, fullerene structures with symmetrically arranged pairs of pentagonal-heptagonal defects were proposed to explain the round shape of giant multilayer fullerene cages. Even though those proposed cages are defective, they belong to the icosahedral point group. Using the Tersoff-Brenner potential, we calculated the shape of the defective fullerenes. It is found that these fullerenes have a rounder shape than structures without defects. The electronic structure of the fullerenes with defects is also calculated within the Huckel approach. The electronic structures are closed and the energy gaps between bonding and antibonding orbitals are higher than those for fullerenes with no defects in almost all cases considered.

Do the Charge-Transfer Complexes of 1,2,4,5-Tetracyanobenzene with Arenes Serve as a Probe for Surveying Chemical Properties Inside the Cavities of Faujasite Zeolites? Time-Resolved and Steady-State Spectroscopic Studies

Charge-transfer (CT) complexes of 1,2,4,5-tetracyanobenzene (TCNB) with arene donor molecules were assembled within the supercages of faujasite zeolites with a two-step adsorption technique from solutions, and the transient absorption characteristics as well as the absorption and emission properties of these complexes were investigated. Several observations were made relevant to these neutral-type CT complexes which are adsorbed with a weak electronic interaction into zeolites rather than the Coulombic attraction which is predominant for the binding of CT complexes of pyridinium acceptors previously studied: (1) the peak position of the CT bands suffers an appreciable shift depending on the chemical nature of the zeolites, (2) the apparent equilibrium constant for the complex formation depends both on the chemical nature of the zeolites and on the arene donors, (3) an appreciable effect of coadsorbed water, which has stronger interaction with the zeolite frameworks than the guest species, on the complex formation is noted, and (4) the relaxation process of the excited CT complexes is significantly retarded (at least 10 times) in dehydrated zeolites compared with that in polar solutions. These points were discussed on a qualitative basis because of the complexity of the systems. The CT complexes of TCNB with arene donors were found to be sensitive to the chemical properties of zeolites while those of pyridinium acceptors with arenes have been reported to be sensitive to the physical properties such as the shape of cages as well as the size of entry apertures of zeolites.