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AbstractA family of structure-dependent integration methods has been proposed by Gui et al. for time integration. Although it has desirable numerical properties, such as unconditional stability, explicit formulation and second-order accuracy, it has some adverse properties, such as a poor capability to capture structural nonlinearity, an overshoot in a high frequency steady- state response and a weak instability in the high frequency response of nonzero initial conditions. The causes of these adverse properties are explored. A poor capability to capture structural nonlinearity may originate from the convergence rate of 1 in velocity error. This family method has an overshoot in a high frequency steady-state response and this overshoot can be eliminated by adding a load-dependent term into the displacement difference equation. It is also analytically verified that the family method generally has no weak instability. However, the special member with λ= 4, i.e., CR explicit method, is shown to have a weak instability. Thus, it must be prohibited from practical applications although many applications of this method were found in the literature.

In 2015, the second cycle of the CONCORD programme established global surveillance of cancer survival as a metric of the effectiveness of health systems and to inform global policy on cancer control. CONCORD-3 updates the worldwide surveillance of cancer survival to 2014.

This study systematically investigates the effects of electrical resistance at the workpiece/electrode interface or electrode face on temperature dependent dynamic resistance during resistance spot welding (RSW). To evaluate temperature transport equations of mass, momentum, energy, species and magnetic field intensity in workpieces, the energy and magnetic equations in the electrode are solved. Contact resistances composed of constriction and film resistances are functions of hardness, temperature, electrode force and surface conditions. The results show that dynamic resistance is complicated due to different variations of film and constriction resistances with temperature at not only the faying surface but also the electrode face in the early stage, i.e. shorter than around 3 cycles. Dynamic resistance in this stage is fortunately insignificant to transport processes. When the power is off, dynamic resistance depends on competition between decreased bulk resistance and increased constriction resistance at the electrode face. Decreased constriction resistance at the electrode face reduces dynamic resistance and temperature.

This work numerically investigates the geometrical effects of the electrode containing a coolant hole on transport variables during resistance spot welding. The model accounts for transient magneto-fluid mechanics, heat and species transport, bulk resistance in workpiece, and film and constriction resistances at contact interfaces. The computed results show that electrode cooling due to the coolant hole influences transport processes during not only freezing and cooling periods but also heating and melting periods. Electrode cooling can be interpreted by thermal resistance, depending on the shapes of the electrode and coolant hole within the growing thermal diffusion layer. Major factors affecting electrode cooling are different in distinct time stages. In most cases, enhanced electrode cooling due to the coolant hole decreases the electrode temperature and nugget growth rate. A decrease in the electrode face radius strongly increases nugget growth rate and workpiece temperature and decreases electrode temperature, whereas its effect on cooling rate is insignificant. The optimum design and sensitivity analysis of the electrode shapes subject to required cooling rate, nugget growth rate and welding time are revealed.

Left liver grafts have been widely utilized in adult liver transplantation (LT) and yielded acceptable results. However, the conventional orthotopic implantation of a left liver graft imposes the potential risk of perioperative vascular complications. We report herein an alternative modified technique for adult left liver LT and evaluate its feasibility in LT. In this study, 10 recipients had their left liver graft rotated 180°, and heterotopically implanted at the right subphrenic space, which we termed “left at right” liver transplantation (LAR‐LT). The sequence of vascular and biliary reconstruction was performed as standard techniques, and no perioperative vascular complications related to LAR‐LT were encountered. There were two mortalities in this series, one due to a small‐for‐size graft dysfunction and the other due to postoperative internal hemorrhage. Two recipients had biliary strictures that were successfully managed by percutaneous biliary dilatation and Roux‐en‐Y hepaticojejunostomy. The clinical characteristics and outcomes of patients undergoing LAR‐LT were also compared with patients undergoing conventional orthotopic left liver LT (n = 14). Although the results showed no significant difference between the two groups, according to our experience, the satisfactory outcome and easier technical reconstruction suggest that the LAR‐LT modification could be a feasible alternative to left liver LT.

Left liver grafts have been widely utilized in adult liver transplantation (LT) and yielded acceptable results. However, the conventional orthotopic implantation of a left liver graft imposes the potential risk of perioperative vascular complications. We report herein an alternative modified technique for adult left liver LT and evaluate its feasibility in LT. In this study, 10 recipients had their left liver graft rotated 180°, and heterotopically implanted at the right subphrenic space, which we termed “left at right” liver transplantation (LAR-LT). The sequence of vascular and biliary reconstruction was performed as standard techniques, and no perioperative vascular complications related to LAR-LT were encountered. There were two mortalities in this series, one due to a small-for-size graft dysfunction and the other due to postoperative internal hemorrhage. Two recipients had biliary strictures that were successfully managed by percutaneous biliary dilatation and Roux-en-Y hepaticojejunostomy. The clinical characteristics and outcomes of patients undergoing LAR-LT were also compared with patients undergoing conventional orthotopic left liver LT (n = 14). Although the results showed no significant difference between the two groups, according to our experience, the satisfactory outcome and easier technical reconstruction suggest that the LAR-LT modification could be a feasible alternative to left liver LT.

ABSTRACTThe effects of distinct properties during phase change on mass, momentum, energy, species, and magnetic field intensity transport in workpieces and electrodes in the course of heating, melting, cooling and freezing periods in AC (alternative current) resistance spot welding are realistically and extensively investigated. Resistance spot welding has been widely used in joining thin workpieces due to its light weight and easy manufacturing. This study accounts for electromagnetic force, heat generations at the electrode-workpiece interface and faying surface between workpieces, and dynamic electrical resistance taking the sum of temperature-dependent bulk resistance of the workpieces and contact resistances at the faying surface and electrode-workpiece interface. The contact resistance is a function of hardness, temperature, electrode force, and surface condition. Instead of dealing with specific materials, this work is a general dimensionless investigation of resistance spot welding of materials with different specific heat and thermal conductivity ratios subject to realistic working parameters. The computed results show that nugget formation is delayed and heat transfer is reduced by increasing solid-to-liquid thermal conductivity and liquid-to-solid specific heat ratio. The corresponding thermal fields and flow patterns are also presented.

Wear characterization with ferrography is an effective off-line method for monitoring a machine's wear condition. The new challenge of real-time wear reporting appeared in condition-based maintenances. Newly developed on-line technologies focus on wear debris concentration rather than on ferrograph images. However, wear rate and wear mechanism are two necessary aspects in describing the wear condition. An on-line ferrograph image provided by an on-line visual ferrograph sensor gives a new solution. By analysing the features of an on-line ferrograph image, new wear characterization with rapid and statistical analysis was investigated for on-line wear reporting. The focus of this method is wear debris chains rather than single wear debris as focused on in traditional ferrography. First, an on-line ferrograph image is preprocessed into a binary image with improved quality. Then the binary image is transformed into a projection curve by parallel radon transformation. The low-frequency component characterizing wear debris chains is extracted from the projection curve by wavelet transformation, which shifts the focus on wear debris chains other than single wear debris. Spectrum analysis is performed to extract the wear characteristics from the low-frequency component of the projection curve. As the main result, two statistical indexes are constructed, as value of point to point and equivalent diameter of larger wear debris, representing the statistical wear debris concentration and the equivalent diameter of larger wear debris, respectively. The indexes correspond qualitatively to wear rate and wear mechanism, respectively. The method was further examined with on-line images from the bench tests of the Eaton engine and the gear reducer of the mine scraper conveyor. The results show that the indexes are effective and independent in describing wear condition, which are promising prospects for on-line wear monitoring with ferrography.

The effects of alternating current (ac) and direct current (dc) on cooling rate, solute distribution and nugget shape after solidification, which are responsible for microstructure of the fusion zone, during resistance spot welding, are realistically and extensively investigated. The computer program developed by Wang and Wei is used to predict transport variables in workpieces and electrodes during heating, melting, cooling and freezing periods. The model accounts for electromagnetic force, heat generations at the electrode/workpiece interface and faying surface between workpieces, and dynamic electrical resistance including bulk resistance and contact resistances at the faying surface and electrode/workpiece interfaces, which are functions of hardness, temperature, electrode force and surface condition. The computed results show that in contrast to dc, using ac readily produces the nugget in an ellipse shape. Deficit and excess of solute content occur in a thin layer around the boundary and interior of the nugget respectively.

Silane moisture‐cured metallocene‐catalyzed polyethylene (mPE) blend to form a novel thermoplastic vulcanizate (TPV) has been prepared. Metallocene polyethylenes with two different levels of comonomer contents were grafted with various amounts of vinyltriethoxy silane. As a result, tensile strength varies slightly with increasing the levels of silane concentrations, at all test temperatures. Tear strength generally decreases with reduced energy dissipation, at higher degrees of cure. “Threshold” fracture energy is roughly proportional to the reciprocal square root of Young's modulus. By relating tensile strength to tear strength, it was found that the corrected average depth of flaw is in the range of 29.3 ± 7.2 μm, which successfully confirms the extension of Rivlin and Thomas's theory for conventional elastomers to TPVs under an elaborate treatment, due to the limitation of the theory. Cutting strength of mPE TPVs gives an intermediate value when compared with that of crystalline plastics and conventional elastomers, which further signifies the importance of crystalline yielding even in the nanofracture zone of deformation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2207–2218, 2005

An accurate evaluation of the absorbed dose to the bladder wall from 2-18Ffluoro-2-deoxy-d-glucose (FDG) is clinically important because the bladder is considered as a critical organ in most positron emission tomography (PET) studies that cumulate about 20 of the total activity injection during image procedures. In the MIRD calculation, no allowance is made for the inclusion of all the dynamic parameters that affect the actual dose to the bladder wall to be taken in the dose assessment. The goal of the study is to propose a dose evaluation model by using a dynamic bladder phantom and time-activity curves from the bladder PET imaging. The proposed model takes all dynamic parameters into account and provides a much more accurate dose estimation to the bladder. In this study, the lowest dose to the bladder wall was obtained at the conditions of having a larger initial volume for the bladder contents and a higher production rate for urine. It is then advised patients to drink a bulk amount of water before the FDG injection or after urine voiding to facilitate urine production and to enlarge the bladder surface area, which are the most crucial steps in reducing the dose to the bladder wall. In our study, the voiding schedule in dose calculation plays certain roles although it is much more critical in the conventional MIRD calculation. The model estimated that the lowest dose to the bladder would occur at an initial void about 40 min after the FDG injection and the urine voiding was as complete as possible.

Nontypeable Haemophilus influenzae (NTHi) is a common cause of otitis media and respiratory tract infections. Outer membrane proteins (OMP) and lipooligosaccharide (LOS) are major surface antigens of NTHi and potential vaccine candidates. De-O-acylated LOS (dLOS) or oligosaccharide (OS) was coupled to total OMP to form dLOS-OMP and OS-OMP conjugates, while a dLOS-tetanus toxoid (TT) was synthesized for comparison. These conjugates were evaluated in mice and rabbits for immunogenicity. dLOS-OMP elicited a better boostable antibody response against LOS than did dLOS-TT, while OS-OMP was not immunogenic. Formulation of the conjugates with Ribi adjuvant significantly enhanced the immunogenicity of dLOS-OMP and dLOS-TT but not that of OS-OMP. In addition, rabbit antisera elicited by dLOS-OMP but not dLOS-TT (or OMP alone) demonstrated bactericidal activity against 40% of the NTHi strains tested. These results indicate that dLOS is a better derivative of LOS than OS and that OMP is a good carrier for NTHi LOS-based conjugate vaccines.

The MutS protein is part of the dam-directed MutHLS mismatch repair pathway in Escherichia coli. We have constructed deletion derivatives in the mutS gene, which retain the P-loop coding region for ATP binding. The mutant proteins were assayed for ATP hydrolysis, heteroduplex DNA binding, heterodimer MutS formation, and the ability to interact with MutL. Dimerization was assayed by expressing His6-tagged wild-type and non-tagged deletion mutant proteins in the same cell and isolating the His6-tagged protein followed by MutS immunoblotting after SDS-polyacrylamide gel electrophoresis. MutS-MutL interaction was measured using the same technique except that the MutL protein carried the His6 tag. Our results indicate that DNA binding ability resides in the N-terminal end of MutS, and dimerization and MutL interactions are located in the C-terminal end. Given the extensive amino acid homology in the MutS family our results with E. coli should be applicable to MutS homologues in other prokaryotes and eukaryotes.

[18F]-2-deoxyglucose (18F-FDG) is one of the most useful radiopharmaceuticals in clinical positron emission tomographic imaging. Its final metabolic destination is the bladder, which accumulates the highest absorbed dose in the body during imaging. The aims of this study were to develop a dynamic bladder phantom to emulate the dynamic response of the bladder and to evaluate changes in the dose to the bladder wall during the imaging procedure. 18F-FDG of various concentrations can be drip-fed intravenously to the balloon-bladder at different uptake phases or extracted from the phantom during voiding. A dose evaluation model, introducing the concept of photon energy flux conversion into the dose calculation, is thus developed for clinical evaluation. The dose to the bladder wall using the proposed model is comparable to that measured using a thermoluminescence dosimeter (TLD), with a less than 5 discrepancy. The main advantages of the model are the use of the dose conversion factor, ΦTLD, which is determined from real TLD measurements, and the ability to consider the dynamic characteristics of the bladder. To overcome the problems of diverse dose distributions among subjects, time-activity information provided by clinical bladder imaging is required, so that the method can be applied to other radiopharmaceuticals.

Many uncertainties are encountered in the evaluation of the stability of the foundations of gravity platforms. These include variability in the properties of the sea floor material and inaccuracies in the method used to determine the shear strength and in the analytical method. The important sources of uncertainty were identified for the site of Statfjord B. Published data, when available, were used to evaluate the magnitudes of the uncertainties, and subjective opinions were used when data were inadequate. A first-order, second-moment analysis was used to evaluate the effect of the uncertainties on the reliability of the foundations. Several criteria for the determination of the undrained shear strength were studied and the corresponding reliabilities were compared. The contributions of new information on undrained shear strength and cyclic shear strength to the reduction in uncertainty were evaluated. On trouve beaucoup d'incertitudes dans 1'evaluation de la stabilité des fondations des plate-formes gravitaires y compris les variations des propriétés de la matière du fond sous-marin et les manques de précision dans la méthode employée pour déterminer la résistance au cisaillement et dans la méthode analytique. Les sources importantes d'incertitude furent identifiées pour I'emplacement de Statfjord B. Les données publiées disponibles furent employées pour évaluer les valeurs des incertitudes. On a présenté des opinions subjectives dans les cas où les données étaient insuffisantes. Une analyse de premier ordre et de deuxieme moment fut employée pour évaluer l'effet des incertitudes sur la fiabilité des fondations. Plusieurs critères pour la détermination de la résistance au cisaillement non-drainée furent étudiés et les fiabilités correspondantes comparées. Les nouveaux renseignements concernant la résistance au cisaillement non-drainée et cyclique furent évalués.

Retinitis pigmentosa is a heterogeneous group of inherited retinal disorders in which the photoreceptor cells degenerate. A line of transgenic mice expresses a mutant opsin gene that encodes three missense mutations near the amino terminus, including P23H, which is the basis for a common form of dominant retinitis pigmentosa. By studying the photoreceptor cells of these mice and their normal littermates, we found that: (1) opsin was routed correctly, (2) the concentration of opsin in the disk membranes appeared normal by freeze fracture analysis, (3) the amount of disk membrane shedding was normal, but (4) the basal disks of the outer segments were disorganized, indicating defective disk membrane morphogenesis. Defective disk membrane morphogenesis appears to result in the formation of fewer mature disks, thus accounting for observed gradual shortening of the photoreceptor outer segments with age. We suggest that abnormal disk membrane morphogenesis is the primary cellular defect that leads to blindness, and that it arises from the inability of nascent disk membranes, containing normal and mutant opsin, to interact normally with each other.

A model for investigating the characteristics of a high-intensity beam on welding cavity shape and temperature distribution is developed. The beam power density is assumed to have a Gaussian distribution. The local heat transfer rate to the liquid-vapor interface depends on this distribution and on the interface contour. This contour as determined by an iterative procedure involves simultaneously satisfying the heat conduction rate into the liquid and equilibrium of the normal forces. Computed shapes of the cavity and the free surface temperature distributions agree well with experimental data. The beam energy flux distribution parameter is found to have the strongest effect on the welding process. The predicted dimensionless curve of the beam power-penetration depth parameter versus the welding velocity-thermal property parameter is also in accord with experimental results. The use of the energy flux distribution parameter instead of the fusion zone width at the workpiece surface for the welding velocity-thermal property parameter is recommended.

The scattering and guidance of electromagnetic waves from a two-dimensionally (2D) periodic metal grating structure are investigated here. With the spectral domain analysis the dispersion characteristics for this structure are obtained. Properly taking into account the hybrid mode nature of the propagation problem the effects of mode coupling betweenTE andTM modes are examined. Numerical results will provide us valuable information for the design of new devices in 2D periodic structure, particularly in millimeter-wave frequency range, such as antennas, filters, couplers and distributed reflectors.