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Unique Design (unique + design)
Selected AbstractsMethods for detecting interactions between genetic polymorphisms and prenatal environment exposure with a mother-child designGENETIC EPIDEMIOLOGY, Issue 2 2010Shuang Wang Abstract Prenatal exposures such as polycyclic aromatic hydrocarbons and early postnatal environmental exposures are of particular concern because of the heightened susceptibility of the fetus and infant to diverse environmental pollutants. Marked inter-individual variation in response to the same level of exposure was observed in both mothers and their newborns, indicating that susceptibility might be due to genetic factors. With the mother-child pair design, existing methods developed for parent-child trio data or random sample data are either not applicable or not designed to optimally use the information. To take full advantage of this unique design, which provides partial information on genetic transmission and has both maternal and newborn outcome status collected, we developed a likelihood-based method that uses both the maternal and the newborn information together and jointly models gene-environment interactions on maternal and newborn outcomes. Through intensive simulation studies, the proposed method has demonstrated much improved power in detecting gene-environment interactions. The application on a real mother-child pair data from a study conducted in Krakow, Poland, suggested four significant gene-environment interactions after multiple comparisons adjustment. Genet. Epidemiol. 34: 125,132, 2010. © 2009 Wiley-Liss, Inc. [source] Design, analysis, and synthesis of generalized single step single solve and optimal algorithms for structural dynamicsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2004X. Zhou Abstract The primary objectives of the present exposition are to: (i) provide a generalized unified mathematical framework and setting leading to the unique design of computational algorithms for structural dynamic problems encompassing the broad scope of linear multi-step (LMS) methods and within the limitation of the Dahlquist barrier theorem (Reference [3], G. Dahlquist, BIT 1963; 3: 27), and also leading to new designs of numerically dissipative methods with optimal algorithmic attributes that cannot be obtained employing existing frameworks in the literature, (ii) provide a meaningful characterization of various numerical dissipative/non-dissipative time integration algorithms both new and existing in the literature based on the overshoot behavior of algorithms leading to the notion of algorithms by design, (iii) provide design guidelines on selection of algorithms for structural dynamic analysis within the scope of LMS methods. For structural dynamics problems, first the so-called linear multi-step methods (LMS) are proven to be spectrally identical to a newly developed family of generalized single step single solve (GSSSS) algorithms. The design, synthesis and analysis of the unified framework of computational algorithms based on the overshooting behavior, and additional algorithmic properties such as second-order accuracy, and unconditional stability with numerical dissipative features yields three sub-classes of practical computational algorithms: (i) zero-order displacement and velocity overshoot (U0-V0) algorithms; (ii) zero-order displacement and first-order velocity overshoot (U0-V1) algorithms; and (iii) first-order displacement and zero-order velocity overshoot (U1-V0) algorithms (the remainder involving high-orders of overshooting behavior are not considered to be competitive from practical considerations). Within each sub-class of algorithms, further distinction is made between the design leading to optimal numerical dissipative and dispersive algorithms, the continuous acceleration algorithms and the discontinuous acceleration algorithms that are subsets, and correspond to the designed placement of the spurious root at the low-frequency limit or the high-frequency limit, respectively. The conclusion and design guidelines demonstrating that the U0-V1 algorithms are only suitable for given initial velocity problems, the U1-V0 algorithms are only suitable for given initial displacement problems, and the U0-V0 algorithms are ideal for either or both cases of given initial displacement and initial velocity problems are finally drawn. For the first time, the design leading to optimal algorithms in the context of a generalized single step single solve framework and within the limitation of the Dahlquist barrier that maintains second-order accuracy and unconditional stability with/without numerically dissipative features is described for structural dynamics computations; thereby, providing closure to the class of LMS methods. Copyright © 2003 John Wiley & Sons, Ltd. [source] What about Design Newness?THE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 6 2009Investigating the Relevance of a Neglected Dimension of Product Innovativeness In several industries, new products are very similar in functional features but compete on their unique design. Firms like Alessi, Apple, Bang & Olufsen, Dyson, or Kartell all follow a design-driven innovation approach and use their products' visual appearance as the main mean for differentiation. In spite of this, design newness is never discussed among the dimensions of product innovativeness. Instead, conceptualizations of product innovativeness mostly focus on a product's technical newness or the changes it implies for the innovating firm or for the market it enters. This paper seeks to build an argument for why design newness should be considered as a dimension of product innovativeness. In addition to providing conceptual rationale, empirical evidence is offered on the influence of design newness on sales performance across a product's life cycle. To be able to put the findings into perspective, the performance effects of design newness are compared with those of technical newness. As several products exemplify that design newness and technical newness can go hand in hand, not only direct performance effects but also interaction effects between both newness dimensions are investigated. The arguments are tested on a sample of 157 new cars launched between 1978 and 2006 in Germany. The automobile industry is selected because of the strategic role of both technical and design aspects in product innovation. Putting a focus on this industry also has the advantage that historical information on car specifics and objective sales data over time are accessible. The results emphasize that both design and technical newness are important drivers of car sales. However, the effects differ widely across the product life cycle. While design newness has a positive impact right after the introduction and persists in strength over time, technical newness drives sales with a lagged effect and decreases toward the end of the life cycle. The test of a combined influence of design newness and technical newness on sales performance produces no significant results. These results open interesting avenues for future research on product innovativeness in general and design newness in particular. For management practice, the findings emphasize the importance of overall product innovativeness, clarify the different performance effects of design and technical newness across the product life cycle, and show the value of creating a unique visual product appearance to positively trigger product diffusion. [source] Numerical and Experimental Analysis of an Axial Flow Left Ventricular Assist Device: The Influence of the Diffuser on Overall Pump PerformanceARTIFICIAL ORGANS, Issue 7 2005Alexandrina Untaroiu Abstract:, Thousands of adult cardiac failure patients may benefit from the availability of an effective, long-term ventricular assist device (VAD). We have developed a fully implantable, axial flow VAD (LEV-VAD) with a magnetically levitated impeller as a viable option for these patients. This pump's streamlined and unobstructed blood flow path provides its unique design and facilitates continuous washing of all surfaces contacting blood. One internal fluid contacting region, the diffuser, is extremely important to the pump's ability to produce adequate pressure but is challenging to manufacture, depending on the complex blade geometries. This study examines the influence of the diffuser on the overall LEV-VAD performance. A combination of theoretical analyses, computational fluid (CFD) simulations, and experimental testing was performed for three different diffuser models: six-bladed, three-bladed, and no-blade configuration. The diffuser configurations were computationally and experimentally investigated for flow rates of 2,10 L/min at rotational speeds of 5000,8000 rpm. For these operating conditions, CFD simulations predicted the LEV-VAD to deliver physiologic pressures with hydraulic efficiencies of 15,32%. These numerical performance results generally agreed within 10% of the experimental measurements over the entire range of rotational speeds tested. Maximum scalar stress levels were estimated to be 450 Pa for 6 L/min at 8000 rpm along the blade tip surface of the impeller. Streakline analysis demonstrated maximum fluid residence times of 200 ms with a majority of particles exiting the pump in 80 ms. Axial fluid forces remained well within counter force generation capabilities of the magnetic suspension design. The no-bladed configuration generated an unacceptable hydraulic performance. The six-diffuser-blade model produced a flow rate of 6 L/min against 100 mm Hg for 6000 rpm rotational speed, while the three-diffuser-blade model produced the same flow rate and pressure rise for a rotational speed of 6500 rpm. The three-bladed diffuser configuration was selected over the six-bladed, requiring only an incremental adjustment in revolution per minute to compensate for and ease manufacturing constraints. The acceptable results of the computational simulations and experimental testing encourage final prototype manufacturing for acute and chronic animal studies. [source] Treatment of incontinence after prostatectomy using a new minimally invasive device: adjustable continence therapyBJU INTERNATIONAL, Issue 4 2005Wilhelm A. Hübner OBJECTIVE To evaluate the safety and efficacy of a new minimally invasive urological implant for incontinence after prostatectomy. PATIENTS AND METHODS The adjustable continence therapy device (ProACTTM, Uromedica, Plymouth, MN, USA) consists of two balloons placed via a perineal approach bilaterally at the bladder neck in patients after prostatectomy. Titanium ports, attached via discrete tubing to each balloon, are placed in the scrotum, allowing for separate volume adjustments of the balloons at any time during and after surgery. Changes in a quality-of-life questionnaire (I-QoL), pad usage and a subjective continence grading score were assessed in 117 consecutive men after implanting the Pro-ACT, at baseline and at 1, 3, 6, 12 and 24 months. RESULTS After a mean (range) follow-up of 13 (3,54) months and with a mean of 3 (0,15) adjustments, 67% of men were dry, using at most one ,security' pad daily; 92% were significantly improved, and 8% showed no improvement. The I-QoL score improved from a median of 34.7 to 66.3 after 2 years (42 men; P <,0.001), the daily pad count decreased from a mean of 6 (1,24)/day to 1 (0,6)/day at 2 years (P < 0.001). Continence achieved at ,,6 months after implantation through incremental adjustment remained durable at ,,2 years in most patients. There were complications during and after surgery in 54 patients, mostly minor and decreasing with increasing expertise, primarily reflecting the development and refinement of the new surgical technique and its instrumentation. Re-implantation for complications was required in 32 patients, with a 75% success rate. CONCLUSIONS The ProACT peri-urethral prosthesis produces durable outcomes equivalent or better than other minimally invasive treatments for incontinence after prostatectomy. Its unique design allows for easy adjustment after surgery to achieve the desired urethral resistance, with no further surgical intervention, thus allowing for an optimum balance between voiding pressures and continence. The promising results reported here suggest that this may be an appropriate, effective and durable first-line treatment to offer men with stress urinary incontinence after prostatectomy. [source] SOFCo Planar Solid Oxide Fuel CellINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 1 2004Liang A. Xue SOFCo-EFS Holdings LLC has developed a multi-layer, planar solid oxide fuel cell (SOFC) stack that has the potential to provide superior performance and reliability at reduced costs. Our approach combines state-of-the-art SOFC materials with the manufacturing technology and infrastructure established for multi-layer ceramic (MLC) packages for the microelectronics industry. With the proper selection of SOFC materials, implementation of MLC fabrication methods offers unique designs for stacks. Over the past two years, substantial progress has been made in the design and manufacturing development of our second-generation stack. Effective stack and manifold seals have been developed. Cell performance has been improved and relatively low non-cell contributions to stack resistance have been achieved. Stack development has been facilitated through the implementation of two key test methods: (1) a 10-cm single-cell test to bridge the gap in performance data obtained from button cell tests (used for cell R&D) and stack tests; and (2) a novel instrumented short stack (<5 cells) that allows for effective isolation of individual contributions to stack resistance. As a result of progress made to date, a clear pathway for improving stack performance has been established, thereby building confidence that commercial stack performance targets will be reached. [source] | ||||||||||