19 research outputs found
Factors Affecting Online Search Intention and Online Purchase Intention
This research focuses on various factors affecting online search intention which has been found to be a key predictor of online purchase intention. Data were collected from a sample consisting of mostly young adults with familiarity of computer use and online shopping experience. A structural equation model was employed to test hypotheses. According to the findings, utilitarian value of Internet information search, hedonic value of Internet information search, perceived benefits of Internet shopping, perceived risk of Internet shopping, and Internet purchase experience predicted online search intention well. The findings also showed that online search intention positively affects online purchase intention. Finally, theoretical and managerial implications are discussed
Kinetic modeling of the plasma pharmacokinetic profiles of ADAMTS13 fragment and its Fc-fusion counterpart in mice
Introduction: Fusion of the fragment crystallizable (Fc) to protein therapeutics is commonly used to extend the circulation time by enhancing neonatal Fc-receptor (FcRn)-mediated endosomal recycling and slowing renal clearance. This study applied kinetic modeling to gain insights into the cellular processing contributing to the observed pharmacokinetic (PK) differences between the novel recombinant ADAMTS13 fragment (MDTCS) and its Fc-fusion protein (MDTCS-Fc).Methods: For MDTCS and MDTCS-Fc, their plasma PK profiles were obtained at two dose levels following intravenous administration of the respective proteins to mice. The plasma PK profiles of MDTCS were fitted to a kinetic model with three unknown protein-dependent parameters representing the fraction recycled (FR) and the rate constants for endocytosis (kup, for the uptake into the endosomes) and for the transfer from the plasma to the interstitial fluid (kpi). For MDTCS-Fc, the model was modified to include an additional parameter for binding to FcRn. Parameter optimization was done using the Cluster Gauss-Newton Method (CGNM), an algorithm that identifies multiple sets of approximate solutions (โacceptedโ parameter sets) to nonlinear least-squares problems.Results: As expected, the kinetic modeling results yielded the FR of MDTCS-Fc to be 2.8-fold greater than that of MDTCS (0.8497 and 0.3061, respectively). In addition, MDTCS-Fc was predicted to undergo endocytosis (the uptake into the endosomes) at a slower rate than MDTCS. Sensitivity analyses identified the association rate constant (kon) between MDTCS-Fc and FcRn as a potentially important factor influencing the plasma half-life in vivo.Discussion: Our analyses suggested that Fc fusion to MDTCS leads to changes in not only the FR but also the uptake into the endosomes, impacting the systemic plasma PK profiles. These findings may be used to develop recombinant protein therapeutics with extended circulation time
Evaluation of partial cranial cruciate ligament rupture with positive contrast computed tomographic arthrography in dogs
Computed tomographic arthrography (CTA) of four cadaveric canine stifles was performed before and after partial cranial cruciate ligament rupture in order to verify the usefulness of CTA examination for the diagnosis of partial cranial cruciate ligament rupture. To obtain the sequential true transverse image of a cranial cruciate ligament, the computed tomography gantry was angled such that the scanning plane was parallel to the fibula. True transverse images of cranial cruciate ligaments were identified on every sequential image, beginning just proximal to the origin of the cranial cruciate ligament distal to the tibial attachment, after the administration of iodinated contrast medium. A significant decrease in the area of the cranial cruciate ligament was identified on CTA imaging after partial surgical rupture of the cranial cruciate ligament. This finding implies that CTA can be used for assessing partial cranial cruciate ligament ruptures in dogs
Assessment of glomerular filtration rate with dynamic computed tomography in normal Beagle dogs
The objective of our study was to determine individual and global glomerular filtration rates (GFRs) using dynamic renal computed tomography (CT) in Beagle dogs. Twenty-four healthy Beagle dogs were included in the experiment. Anesthesia was induced in all dogs by using propofol and isoflurane prior to CT examination. A single slice of the kidney was sequentially scanned after a bolus intravenous injection of contrast material (iohexol, 1 mL/kg, 300 mgI/mL). Time attenuation curves were created and contrast clearance per unit volume was calculated using a Patlak plot analysis. The CT-GFR was then determined based on the conversion of contrast clearance per unit volume to contrast clearance per body weight. At the renal hilum, CT-GFR values per unit renal volume (mL/min/mL) of the right and left kidneys were 0.69 ยฑ 0.04 and 0.57 ยฑ 0.05, respectively. No significant differences were found between the weight-adjusted CT-GFRs in either kidney at the same renal hilum (p = 0.747). The average global GFR was 4.21 ยฑ 0.25 mL/min/kg and the whole kidney GFR was 33.43 ยฑ 9.20 mL/min. CT-GFR techniques could be a practical way to separately measure GFR in each kidney for clinical and research purposes
Virtual Source Array-Based Multiple Time-Reversal Focusing
Time reversal (TR) is the process of generating a spatio-temporal focus at a probe source (PS) location by transmitting a time-reversed version of a received signal. While TR focusing requires the PS for a coherent acoustic focus at its origin, the requirement of the PS has been partially relaxed by the introduction of the concept of a virtual source array (VSA) (J. Acoust. Soc. Am. 2009, 125, 3828โ3834). A VSA can serve as a remote platform or lens and redirect a focused field to a selected location beyond the VSA for which the field is assumed as a homogeneous medium with constant sound speed. The objective of this study is to extend VSA-based single TR focusing to simultaneous multiple focusing. This is achieved using the optimization theory by employing the multiple constraints method derived from a constraint matrix, which consists of appropriately synchronized transfer functions. Through numerical simulations, it is found that simultaneous multiple focusing can be achieved with distortionless response at selected multiple locations, and its performance degrades in the presence of sound speed mismatch. For achieving robust multiple focusing in the mismatch environment, singular value decomposition is applied to obtain the weight vector (i.e., backpropagation vector) that best approximates the column vectors of the constraint matrix. Numerical simulation results show that VSA-based multiple TR focusing using SVD is not a method to simultaneously focus on multiple locations, but a method of constructing a field which robustly passes through multiple locations in sound speed mismatch environment
A Systematic Removal of Minimum Implant Area Violations under Timing Constraint
Fixing minimum implant area (MIA) violations in the post-route layout is an essential and inevitable task for the high-performance designs employing multiple threshold voltages. Unlike the conventional approaches, which have tried to locally move cells or reassign V-t (threshold voltage) of some cells in a way to resolve the MIA violations with little or no consideration of timing constraint, our proposed approach fully and systematically controls the timing budget during the removal of MIA violations. Precisely, our solution consists of three sequential steps: (1) performing critical path aware cell selection for V-t reassignment to fix the intra-row MIA violations while considering timing constraint and minimal power increments; (2) performing a theoretically optimal V-t reassignment to fix the inter-row MIA violations while satisfying both of the intra-row MIA and timing constraints; (3) refining V-t reassignment to further reduce the power consumption while meeting intra- and inter-row MIA constraints as well as timing constraints. Experiments through benchmark circuits show that our proposed approach is able to completely resolve MIA violations while ensuring no timing violation and achieving much less power increments over that by the conventional approaches.N
Minimum Implant Area-Aware Threshold Voltage Refinement in Pre-Placement
Using multiple threshold voltages (Multi-V-t) is widely adopted due to its effectiveness to optimize the balance between power and timing In the meantime, as the technology node shrinks, the minimum implant area (MIA) constraint has become an emerging challenge in multi-V-t circuit designs. In this paper, we propose an MIA-aware V-t refinement algorithm to be performed in a way to reduce the number of occurrences of MIA violations. Our key idea is to update the V-t of small size cells that are likely to incur MIA violations in advance before cell placement, thereby relieving the burden of fixing MIA violations during the placement stage that performs the operations of moving/swapping cells or trading circuit timing with V-t change. Through experiments with benchmark circuits, it is shown that our proposed method is able to reduce the number of MIA violations by up to 16% with no timing penalty.N
Does market-oriented institutional change in an emerging economy make business-group-affiliated multinationals perform better? An institution-based view
Viewing market-oriented institutional change as a two-staged process, we propose that the effects of market-oriented institutional change on two organizational forms โ business-group-affiliated and independent firms โ are different, depending on the stage of institutional change. Specifically, we examine how the two distinct periods of market-oriented institutional change โ that is, institutional friction and institutional convergence โ affect business-group-affiliated firms and independent firms in their abilities to profit from international diversification. Using data on 140 Korean manufacturing multinational firms from 1993 to 2003, we find that emerging-economy firms face an international diversification discount โ a negative relationship between international diversification and firm performance. We also find that business group affiliation affects the international diversification discount differently during the two periods of market-oriented institutional change, particularly when firm performance is measured by the market-to-book value (MBV). The moderating effect of business group affiliation on the relationship between international diversification and MBV is negative during the institutional frictions period, but becomes positive during the institutional convergence period in the later stage of institutional change. Our findings warn against viewing market-oriented institutional change as a discrete event, highlighting the importance of recognizing the qualitatively distinctive nature of different periods of market-oriented institutional change in future research.