Outer Cage Research Articles

A New Role for Annexin A11 in the Early Secretory Pathway via Stabilizing Sec31A Protein at the Endoplasmic Reticulum Exit Sites (ERES)

Exit of cargo molecules from the endoplasmic reticulum (ER) for transport to the Golgi is the initial step in intracellular vesicular trafficking. The coat protein complex II (COPII) machinery is recruited to specialized regions of the ER, called ER exit sites (ERES), where it plays a central role in the early secretory pathway. It has been known for more than two decades that calcium is an essential factor in vesicle trafficking from the ER to Golgi apparatus. However, the role of calcium in the early secretory pathway is complicated and poorly understood. We and others previously identified Sec31A, an outer cage component of COPII, as an interacting protein for the penta-EF-hand calcium-binding protein ALG-2. In this study, we show that another calcium-binding protein, annexin A11 (AnxA11), physically associates with Sec31A by the adaptor function of ALG-2. Depletion of AnxA11 or ALG-2 decreases the population of Sec31A that is stably associated with the ERES and causes scattering of juxtanuclear ERES to the cell periphery. The synchronous ER-to-Golgi transport of transmembrane cargoes is accelerated in AnxA11- or ALG-2-knockdown cells. These findings suggest that AnxA11 maintains architectural and functional features of the ERES by coordinating with ALG-2 to stabilize Sec31A at the ERES.

Combined Explicit Finite and Discrete Element Methods for Rotor Bearing Dynamic Modeling

This article presents a new approach in which the explicit finite element method (EFEM) and the discrete element method (DEM) are coupled to investigate dynamics of flexible rotor systems supported by deep-groove ball bearings. In this investigation, DEM is used to develop the bearing (dynamic motion) model in which all of the components of the bearing (i.e., inner and outer race, balls, and cage) have 6 degrees of freedom. The flexible shaft is modeled with a full 3D elastic formulation using the EFEM rather than the reduced form, which implements component mode synthesis. The EFEM and DEM were combined to investigate the dynamics of flexible shaft rotor systems supported by ball bearings. Rotor and inner races of the bearings are fully coupled such that both translation and rotation of the flexible rotor are transmitted to the bearings. At each time step, the translational motion and rotation/tilt angle of the rotor cross section at the location of an inner race are applied to the inner race of the bearing. The resulting reaction forces and moments calculated in the dynamic bearing model are in turn applied to the nodes of the shaft. The combined model is used to investigate the motions of the inner races and the resulting reaction forces and moments from the supporting bearings due to an applied load on the shaft. In the current coupled modeling approach, the deformation of the shaft affects the internal components of the bearing by altering the orientation of the inner race, which results in ball spin and slip.

Advanced Diagnosis of Outer Cage Damage in Double-Squirrel-Cage Induction Motors Under Time-Varying Conditions Based on Wavelet Analysis

It is known that classical fast-Fourier-transform-based steady-state spectrum analysis, such as motor current signature analysis, may fail to detect outer cage damage in double-squirrel-cage induction motors. This is because the magnitude of the rotor fault frequency components (RFFCs) in the current spectrum of faulty motors is small, due to the low-magnitude current circulation in the outer cage under a steady-state operation. The probability of misdetection is higher in time-varying load applications, such as conveyor belts, pulverizers, etc., for which double-cage motors are frequently employed. In case of load variation, the small RFFCs are spread in a bandwidth proportional to the speed variation, which makes them even more difficult to detect. A diagnosis method based on discrete wavelet transform and optimized for sensitive detection under transient operating conditions is proposed in this paper. An experimental study on a custom-built fabricated Cu double-cage-rotor induction motor shows that the proposed method can provide improved detection of outer cage faults particularly used in time-varying load applications.

Portable hermetic storage bag resistant to Prostephanus truncatus, Rhyzopertha dominica, and Callosobruchus maculatus

Portable hermetic storage bag, SuperGrainbags™ (SGBs) was tested against insect penetration Prostephanus truncatus, Rhyzopertha dominica, and Callosobruchus maculatus. Measurements of oxygen level, insect mortality, and insect damage were determined during six weeks. A new type of multi-layer SGB-IV-R co-extruded, with its ultra-low oxygen permeability of less than 4 cc/m2/day filled with grains of maize, wheat, and cowpea allows a significant decrease in the oxygen level after two weeks of storage. By week 4, 100% mortality of insects is located inside the bag (≤5 insect/kg) was observed. However, the trapped insects placed between the SGB-IV-R and outer mesh cage with no deprivation of oxygen ultimately penetrated from the outside. Under artificial insect density at 10 insect/kg, the SGB-IV-R was punctured after 3 and 6 weeks by the P. truncatus and R. dominica, respectively but no for C. maculatus. In summary, when insect infestation is coming from grain harvest, successful control of all insects was achieved by SGB-IV-R, but effects of infestation from outside under natural (untrapped) field conditions needs to be validated.

ChemInform Abstract: New Features in Coordination Chemistry: Valuable Hints from X‐Ray Analyses of Endohedral Metallofullerenes

AbstractReview: 67 refs.

Defect induced electronic structure of uranofullerene.

The interaction between the inner atoms/cluster and the outer fullerene cage is the source of various novel properties of endohedral metallofullerenes. Herein, we introduce an adatom-type spin polarization defect on the surface of a typical endohedral stable U2@C60 to predict the associated structure and electronic properties of U2@C61 based on the density functional theory method. We found that defect induces obvious changes in the electronic structure of this metallofullerene. More interestingly, the ground state of U2@C61 is nonet spin in contrast to the septet of U2@C60. Electronic structure analysis shows that the inner U atoms and the C ad-atom on the surface of the cage contribute together to this spin state, which is brought about by a ferromagnetic coupling between the spin of the unpaired electrons of the U atoms and the C ad-atom. This discovery may provide a possible approach to adapt the electronic structure properties of endohedral metallofullerenes.

The Highly Conserved COPII Coat Complex Sorts Cargo from the Endoplasmic Reticulum and Targets It to the Golgi

Protein egress from the endoplasmic reticulum (ER) is driven by a conserved cytoplasmic coat complex called the COPII coat. The COPII coat complex contains an inner shell (Sec23/Sec24) that sorts cargo into ER-derived vesicles and an outer cage (Sec13/Sec31) that leads to coat polymerization. Once released from the ER, vesicles must tether to and fuse with the target membrane to deliver their protein and lipid contents. This delivery step also depends on the COPII coat, with coat proteins binding directly to tethering and regulatory factors. Recent findings have yielded new insight into how COPII-mediated vesicle traffic is regulated. Here we discuss the molecular basis of COPII-mediated ER-Golgi traffic, focusing on the surprising complexity of how ER-derived vesicles form, package diverse cargoes, and correctly target these cargoes to their destination.

単分子内包炭素クラスターの合成と固体物性探索

In the point of a demonstration of its fundamental properties compared with bulk water,a single water molecule within a confined subnano space is one of the important topics in both material and life sciences. However, a single molecule of H2O, that is completely isolated without any hydrogen bonds, is rare so far because water usually exists in hydrogen-bonded environments.The inner space of the fullerene C60 is suitable to entrap a water molecule.It would be possible to control the properties of the outer carbon cage as well as to study the isolated specieswhen atoms or molecules are encapsulated in fullerenes.Endohedral fullerenes encapsulating a wide variety of species, such as metal ions and rare gases, have been synthesized with physical methods under harsh conditions. However, these methods are not suitable to obtain endohedral fullerenes encapsulating small molecules.

Detection of Broken Outer-Cage Bars for Double-Cage Induction Motors Under the Startup Transient

Unlike single-cage rotor fault detection, fast Fourier transform (FFT)-based steady-state spectrum analysis techniques can fail to detect outer-cage faults in double-cage induction motors due to the small outer-cage current under running conditions. Double-cage motors are typically employed in applications that require loaded starts. This makes the outer cage vulnerable to fatigue failure since it must withstand the high starting current and long startup time frequently. However, there are only a few publications that investigate detection techniques specifically for double-cage motors. In this paper, considering that the influence of the faulty outer cage is strong at startup due to the large outer-cage current, detection of outer-cage faults under the startup transient is investigated. A discrete-wavelet-transform-based method is proposed as a viable solution to the detection of outer-cage faults for double-cage motors. An experimental study on fabricated copper double-cage induction motors shows that the proposed method provides sensitive and reliable detection of double-cage rotor faults compared to FFT.

New features in coordination chemistry: Valuable hints from X-ray analyses of endohedral metallofullerenes

The cage-like structure of fullerenes enables a new strategy for derivatization, that is, endohedral doping with metallic species. Distinctly different from exohedral metal-fullerene complexes, endohedral metallofullerenes (EMFs) show several new features in metal–carbon interactions which result from the electron transfer from the internal metallic species to the outer carbon cage. Taking advantage of recent achievements in the X-ray crystallographic characterization of EMFs, it was revealed that the single metal cation in mono-EMFs are always apart from the cage center, coordinating with the cage from inside, dominantly via electrostatic interactions, whereas the metal–cage interactions are much weaker in di-EMFs, featuring a moving dimetallic cluster in most cases. Moreover, formation of various metallic cluster species inside the fullerene cage suggest that the strong coordination ability of rare earth metals which always requests a maximal coordinated stereo environments, is a critical factor controlling the formation of stable EMF compounds. Finally, the structural features of the fullerene cage, such as the symmetry, the shape and the size, are also found to exert fundamental influences on the metal location or motion.

Twisted Cardiovascular Cages for Intravascular Axial Flow Blood Pumps to Support the Fontan Physiology

Failing single ventricle physiology represents an ongoing challenge in mechanical assist device development, requiring pressure augmentation in the cavopulmonary circuit, reduction of systemic venous pressure, and increased cardiac output to achieve hemodynamic stabilization. To meet these requirements, we are developing a percutaneously-placed, axial flow blood pump to support ailing single ventricle physiology in adolescents and adults. We have modified the outer cage of the device to serve as both a protective and functional design component. This study examined the performance of 3 cage geometries with varying directions of filament twist using numerical simulations and hydraulic experiments. All 3 cage and pump models performed in acceptable ranges to support Fontan patients. The cage design employing filaments that are twisted in the opposite direction to the impeller blades and in the direction of the diffuser blades (against-with) demonstrated superior performance by generating a pressure rise range of 5-38 mmHg of flow rates of 0.5-6 l/min at rotational speeds of 5000-7000 rpm. The blood damage indices for all of the cages were found to be well below 2%, and the scalar stress levels were below 200 Pa. This study represents ongoing progress in the development of the impeller and cage assembly. Validation of the results will continue in experiments with blood bag evaluation as well as by particle image velocimetry measurements.

Confirmation of Thermal Images and Vibration Signals for Intelligent Machine Fault Diagnostics

This paper deals with the maintenance technique for industrial machinery using the artificial neural network so-called self-organizing map (SOM). The aim of this work is to develop intelligent maintenance system for machinery based on an alternative way, namely, thermal images instead of vibration signals. SOM is selected due to its simplicity and is categorized as an unsupervised algorithm. Following the SOM training, machine fault diagnostics is performed by using the pattern recognition technique of machine conditions. The data used in this work are thermal images and vibration signals, which were acquired from machine fault simulator (MFS). It is a reliable tool and is able to simulate several conditions of faulty machine such as unbalance, misalignment, looseness, and rolling element bearing faults (outer race, inner race, ball, and cage defects). Data acquisition were conducted simultaneously by infrared thermography camera and vibration sensors installed in the MFS. The experimental data are presented as thermal image and vibration signal in the time domain. Feature extraction was carried out to obtain salient features sensitive to machine conditions from thermal images and vibration signals. These features are then used to train the SOM for intelligent machine diagnostics process. The results show that SOM can perform intelligent fault diagnostics with plausible accuracies.

Plastic Bearing Fault Diagnosis Based on a Two-Step Data Mining Approach

Plastic bearings are widely used in medical applications, food processing industries, and semiconductor industries. However, no research on plastic bearing fault diagnostics using vibration sensors has been reported. In this paper, a two-step data mining-based approach for plastic bearing fault diagnostics using vibration sensors is presented. The two-step approach utilizes envelope analysis and empirical mode decomposition (EMD) to preprocess vibration signals and extract frequency domain and time domain fault features as condition indicators (CIs) for plastic bearing fault diagnosis. In the first step, the frequency domain CIs are used by a statistical classification model to identify bearing outer race faults. In the second step, the time domain CIs extracted using EMD are developed to build a k-nearest neighbor algorithm-based fault classifier to identify other types of bearing faults. Seeded fault tests on plastic bearing outer race, inner race, balls, and cage are conducted on a bearing diagnostic test rig and real vibration signals are collected. The effectiveness of the presented fault diagnostic approach is validated using the plastic bearing seeded fault testing data.

Data Mining Based Full Ceramic Bearing Fault Diagnostic System Using AE Sensors

Full ceramic bearings are considered the first step toward full ceramic, oil-free engines in the future. No research on full ceramic bearing fault diagnostics using acoustic emission (AE) sensors has been reported. Unlike their steel counterparts, signal processing methods to extract effective AE fault characteristic features and fault diagnostic systems for full ceramic bearings have not been developed. In this paper, a data mining based full ceramic bearing diagnostic system using AE based condition indicators (CIs) is presented. The system utilizes a new signal processing method based on Hilbert Huang transform to extract AE fault features for the computation of CIs. These CIs are used to build a data mining based fault classifier using a k-nearest neighbor algorithm. Seeded fault tests on full ceramic bearing outer race, inner race, balls, and cage are conducted on a bearing diagnostic test rig and AE burst data are collected. The effectiveness of the developed fault diagnostic system is validated using real full ceramic bearing seeded fault test data.

A Study on Measuring Method for 3D Motion of Balls in High-Speed Ball Bearings

In order to simply and accurately measure the realistic motion of balls in a ball bearing, a method called the static oblique coordinates is proposed to measure the 3D motion of balls in an angular contact ball bearing. This measuring method utilizes Hall elements as the sensors which are assembled on the side of outer race and cage of the ball bearing with magnetized balls. The voltage signals of the Hall sensors are collected online and applied to calculate and analyze the variation of magnetic axis of the magnetized ball, from which the 3D motion of the balls can be calculated. The basic principles and experiment method of the measuring method are illustrated. This method has simple structure without damaging the bearing, by which the bearing’s real motion can be studied consequently with a high precision. The magnetization and magnetic pole detection methods in this study effectively solved the problem of magnetized balls’ magnetism un-uniformity which causes the measure signal chaos.

Structural, electronic and magnetic properties of GdSin ([formula omitted]) clusters: A density functional study

The geometries, stabilities, electronic and magnetic properties of GdSin (n=1–17) clusters have been investigated systematically by using density functional theory (DFT) with the generalized gradient approximation (GGA). We find that the Gd atom in the lowest-energy configuration gradually moves from convex to surface, and to the interior site as the number of Si atom varies from 1 to 17. Furthermore, from GdSi16, Gd atom in GdSi16 cluster completely falls into the center of the Si framework and forms a fullerene cage. On the basis of the atomic average binding energy [Eb(n)], the second difference in energy (Δ2E) and VIP, we predict that the magic number of GdSin (n=1–17) clusters should be 5, 11 and 16, and these clusters should be abundant in the mass spectra when n=5, 11 and 16. The magnetic moments of the GdSin clusters are also studied. It is found that the total magnetic moments and the magnetic moments on Gd of GdSin clusters are large, and they do not quench when Gd is encapsulated in Si outer framework cage, which is to a large extent due to the fact that the Gd 4f electrons hardly interact with the silicon cage.

Filament Support Spindle for an Intravascular Cavopulmonary Assist Device

We are developing an intravascular axial flow blood pump to support adolescent and adult Fontan patients. To protect the blood vessel, this pump has an outer cage with radially arranged filaments and a newly designed spindle at the pump outlet. The outlet spindle is included to limit the axial movement of the rotor and to house bearings that support the rotor. This study evaluates the impact of the outlet spindle on pump performance using computational fluid dynamics (CFD) and experimental testing of a prototype configuration. We measured the pressure-flow performance of the prototype with a protective cage using a blood analog fluid. The pump with the cage filaments and spindle generated 1 to 16mmHg of pressure rise for flow rates of 1 to 4L/min at 4000 to 7000rpm. The difference between the CFD predictions and experimental results was found to be approximately 9.8%. Scalar stress levels remained below 570Pa with exposure times on the order of 1.5s. These results are acceptable and support the continued development of this cavopulmonary assist device with an outlet spindle to reinforce the protective cage filament design.

NC unit trapped by fullerenes: a density functional theory study on Sc3NC@C2n (2n = 68, 78 and 80)

Endohedral metallofullerenes (EMFs) with a trapped cluster size larger than four are rather scarce. Inspired by a recent experimental observation, we explored the possibility of encapsulating an unusual Sc(3)NC unit in three representative fullerene cages, namely, C(68), C(78) and C(80), by means of density functional computations. The geometries, electronic and electrochemical redox properties of the corresponding EMFs, Sc(3)NC@C(2n) (2n = 68, 78 and 80), were investigated. These novel EMFs all have very favorable binding energies, implying a considerable possibility for experimental realization. The recently observed m/z = 1121 peak in the mass spectroscopy was characterized as Sc(3)NC@C(80). Notably the lowest-energy isomer of Sc(3)NC@C(78) has a non-IPR C(78) outer cage, the possibility to accommodate five atoms inside a fullerene as small as C(68) is also intriguing. Moreover, the intracluster and metal-cage covalent interactions were revealed by a quantum theory of atoms in molecules study. Infrared absorption spectra and (13)C nuclear magnetic resonance spectra were also computed to assist future experimental characterization.

Rational synthesis, enrichment, and 13C NMR spectra of endohedral C60 and C70 encapsulating a helium atom

Endohedral fullerenes encapsulating a helium atom, i.e., He@C(60) and He@C(70), at occupation levels of 30% were prepared by rational chemical synthesis. The existence of weak interactions between the inner helium and the outer fullerene cages was demonstrated by experimental and computational investigations.

Effects of vanadium(V)-substitution on the oxidative properties of α-Keggin-type heteropolyanion clusters—progress in DFT theoretical studies

The redox properties of α-Keggin-type heteropolyanion clusters [XM12O40] n− (X = Si, P; M = Mo, W) mainly depend on their constituent outer metal-oxygen cages {M12O36}. They act as “reservoirs”, through which the transfer and transition of electrons and protons may occur. At the atomic and molecular level, the redox properties of these clusters can be controlled and also tuned by modifying the metal M in the cages and the central heteroatom X of the clusters. Combined with relevant experimental results, this review summarizes our recent theoretical investigations of the effect of vanadium substitution on the redox properties of Keggin anion clusters. Theoretical modeling and calculation results showed that the oxidative ability of the modified species was increased by partial substitution of the cage M atoms of the Keggin clusters by vanadium atoms which have lower electronegativity. A linear correlation between the catalytic efficiency per vanadium atom and the microstructures of the vanadium(V)-substituted heteropolyanions [PV n Mo12−n O40](3+n)− (n = 1−3) was established for the first time. This relationship may be suitable to interpret the catalytic behavior of the title compounds in the hydroxylation of benzene to phenol, and may also be used in understanding other reactions such as the oxidative dehydrogenation of isobutyric acid and the nitration of adamantine. The establishment of this nearly linear structure-property relationship may lay the foundations of understanding the behavior of the title compounds in homogeneous catalytic oxidation reactions, and may direct the design of future catalysts and the choice of other catalytic reactions.