bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of a 5-SS Spatial Steering Linkage
Authors: Plecnik Mark M. , McCarthy J. Michael 
Published: September 2013

This paper presents the kinematic synthesis of a steering linkage that changes track, wheelbase, camber, and wheel height in a turn, while maintaining Ackermann geometry. Each wheel is controlled by a 5-SS platform linkage, which consists of a moving platform connected by five SS chains to the vehicle chassis. Ackermann steering geometry ensures all four wheels will travel on circular arcs that share the same center point. S denotes a spherical or ball-in-socket joint.
The kinematic synthesis problem is formulated using seven spatial task positions. The procedure computes the SS chains that guide the platform through the seven task positions, and examines all combinations of five that form a single degree-of-freedom linkage. A kinematic analysis identifies the performance of each design candidate, and eliminates functional defects.
In the design process, the task positions are modified randomly within constraints in order to find a useful mechanism design. Mechanisms are deemed useful if they travel smoothly through all seven task positions. Upon analyzing 1000 sets of task positions, only 10 useful mechanisms were found. A second iteration produced 22 useful mechanisms from 1000 task sets. An example of the design of a steering linkage is presented. A video of this linkage can be seen at http://www.youtube.com/watch?v=hEvbDiyQMiw.
A Method for Measuring Programmatic Dependency and Interdependency Between DoD Acquisition Programs
Authors: Christensen Matthew B. , Wirthlin J. Robert 
Published: September 2013

Large and complex enterprises that are primarily involved in product development and design often must manage their development portfolios against a backdrop of competing demands and realities. Given an existing product development process, there is currently no accepted method for quantitative measurement of development program interdependency. While some methods exist for measuring dependency or interdependency at the component or system level, these methods do not translate well to program interdependency measurement. This paper presents a model for measuring development program interdependency accurately and quantitatively.
The model uses four Interdependency Factors to identify dependency relationships between programs. Specific Interdependency Levels are then used to measure the strengths of those dependencies. The model also accounts for measurement of dependencies upon programs that are not directly connected, i.e., programs that have a degree of separation from another program, and measurement of program criticality, or the extent to which a program is depended-upon by another program.
In this paper, a small portion of the US Air Force’s product development portfolio is examined and used to demonstrate these measures. The measurement model is applied to an example development program to measure program dependency characteristics. The results demonstrate that the model can be effectively used to identify and measure program dependencies. The model gives the program manager a quantitative tool to determine how much a program depends upon other programs and the potential impacts of those dependencies. With this information, program managers can better protect their programs from vulnerabilities associated with interdependency effects from other programs and portfolio managers are given new insights into the management of their portfolio in the product development processes of the enterprise.
Iwan Models and Their Provenance
Authors: Segalman Daniel J. , Starr Michael J. 
Published: September 2013

Iwan models have had some exposure recently in modeling the nonlinear response of individual joints. This popularity can be ascribed to their mathematical simplicity, their versatility, and their ability to capture the important responses of mechanical joints under unidirectional loads. There is a lot of history to this category of model. Masing explored kinematic hardening of metals with a model consisting of ten Jenkins elements in series. Soon after, Prandtl explored the behavior of a continuous distribution of such elements. Ishlinskii explored the mathematical structure of such continuous distributions. Much more recently, Iwan demonstrated practical application of such models in capturing various sorts of metal plasticity.
Among the features that make such models interesting is a simple relationship between the asymptotic nature of the integral kernel at small values and the power-law relation between force amplitude and dissipation per cycle in harmonic loading. Iwan provided several differential equations for deducing the kernel from force-displacement relations. Segalman and Starr devised methods for deducing kernels from force-displacement curves of arbitrary Masing models. This is illustrated to generate a BPII model equivalent to the Ramberg-Osgood plasticity model. The Segalman-Starr relationship is used to find relationships among several other plasticity models.
Say What? The Activity of the Polyamine Biosynthesis Inhibitor Difluoromethylornithine in Chemoprevention Is a Result of Reduced Thymidine Pools?
Authors: Casero Robert A. 
Published: September 2013

Abstract
Summary: In this issue of Cancer Discovery, Witherspoon and colleagues use an unbiased metabolite profiling approach to study the effects of polyamine depletion by 2-difluoromethylornithine in colon cancer cells. Their surprising findings indicate that it is a decrease in thymidine pools resulting from altered tetrahydrofolate availability rather than decreases in polyamines that produces cytostasis. Cancer Discov; 3(9); 975–7. ©2013 AACR.
See related article by Witherspoon et al., p. 1072
Error Estimates for Ocean Surface Winds: Applying Desroziers Diagnostics to the Cross-Calibrated, Multiplatform Analysis of Wind Speed
Authors: Hoffman Ross N. , Ardizzone Joseph V. , Leidner S. Mark , Smith Deborah K. , Atlas Robert 
Published: September 2013

Abstract
The Desroziers diagnostics (DD) are applied to the cross-calibrated, multiplatform (CCMP) ocean surface wind datasets to estimate wind speed errors of the ECMWF background, the microwave satellite observations, and the resulting CCMP analysis. The DD confirm that the ECMWF operational surface wind speed error standard deviations vary with latitude in the range 0.8–1.3 m s−1 and that the cross-calibrated Remote Sensing Systems (RSS) wind speed retrievals’ standard deviations are in the range 0.5–0.7 m s−1. Further, the estimated CCMP analysis wind speed standard deviations are in the range 0.2–0.3 m s−1. The results suggest the need to revise the parameterization of the errors of the first guess at appropriate time (FGAT) procedure. Errors for wind speeds &lt;16 m s−1 are homogeneous; however, for the relatively rare but critical higher wind speed situations, errors are much larger.
Effectiveness of the National Program of Complementary Feeding for older adults in Chile on vitamin B12 status in older adults; secondary outcome analysis from the CENEX Study (ISRCTN48153354)
Authors: Sanchez Hugo , Albala Cecilia , Lera Lydia , Dangour Alan D , Uauy Ricardo 
Published: September 2013

Abstract

Background
Older people are at increased risk of vitamin B12 deficiency and the provision of fortified foods may be an effective way to ensure good vitamin B12 status in later life.

Aim
To evaluate the effectiveness of a vitamin B12 fortified food provided by a national program of complementary food for older people on plasma vitamin B12 levels.

Subjects and methods
A random sub-sample of 351 subjects aged 65-67y from a large cluster randomised controlled trial provided blood samples at baseline and after 24 months of intervention. The intervention arm (10 clusters 186 participants) received a vitamin B12 fortified food designed to deliver 1.4 μg/day, while the control arm did not receive complementary food (10 clusters, 165 participants). Serum vitamin B12 and folate levels determined by radioimmunoassay were used to estimate the effect of intervention on vitamin B12 levels, adjusting for baseline levels and sex.

Results
Attrition at 24 months was 16.7% and 23.6% in the intervention and control arms respectively (p = 0.07). Over 24 months of intervention, mean (95% CI) serum vitamin B12 decreased from 392 (359–425) pmol/dL to 357 (300–414) pmol/dL (p < 0.07) in the intervention arm and from 395 (350–440) pmol/dL to 351 (308–395) pmol/dL in the control arm. There was no significant effect of the intervention on folate status.

Discussion
Our findings suggest that foods fortified with 1.4 μg/daily vitamin B12 as provided by Chile’s national programme for older people are insufficient to ensure adequate vitamin B12 levels in this population. Chile has a long and successful experience with nutrition intervention programs; however, the Country’s changing demographic and nutritional profiles require a constant adjustment of the programs.
Takayasu's arteritis is associated with HLA-B*52, but not with HLA-B*51, in Turkey
Authors: Sahin Ziver , Bıcakcıgil Muge , Aksu Kenan , Kamali Sevil , Akar Servet , Onen Fatos , Karadag Omer , Ozbalkan Zeynep , Ates Askin , Ozer Huseyin TE , Yilmaz Vuslat , Seyahi Emire , Ozturk Mehmet A , Cefle Ayse , Cobankara Veli , Onat A Mesut , Tunc Ercan , Düzgün Nursen , Aydin Sibel Z , Yilmaz Neslihan , Fresko İzzet , Karaaslan Yasar , Kiraz Sedat , Akkoc Nurullah , Inanc Murat , Keser Gokhan , Uyar F Aytul , Direskeneli Haner , Saruhan-Direskeneli Güher ,   the Turkish Takayasu Study Group
Published: September 2013

Abstract

Introduction

HLA-B*51 and HLA-B*52 are two close human leukocyte antigen (HLA) allele groups with minor amino acid differences. However, they are associated with two different vasculitides (HLA-B*51 in Behçet's disease and HLA-B*52 in Takayasu's arteritis (TAK)) and with major clinical and immunological differences. In this study, we aimed to screen a large cohort of TAK patients from Turkey for the presence of HLA-B*51 and HLA-B*52 as susceptibility and severity factors.

Methods

TAK patients (n = 330) followed at a total of 15 centers were included in the study. The mean age of the patients was 37.8 years, and 86% were women. DNA samples from the patients and healthy controls (HC; n = 210) were isolated, and the presence of HLA-B*51 or HLA-B*52 was screened for by using PCR with sequence-specific primers.

Results

We found a significant association of HLA-B*52 with TAK (20.9% vs HC = 6.7%, P = 0.000, OR = 3.7, 95% CI = 2.02 to 6.77). The distribution of HLA-B*51 did not differ between TAK patients and HCs (22.7% vs 24.8%, OR = 0.9, 95% CI = 0.60 to 1.34). The presence of HLA-B*52 decreased in late-onset patients (> 40 years of age; 12.0%, P = 0.024, OR = 0.43, 95% CI = 0.20 to 0.91). Patients with angiographic type I disease with limited aortic involvement also had a lower presence of HLA-B*52 compared to those with all other disease subtypes (13.1% vs 26%, P = 0.005, OR = 0.43, 95% CI = 0.23 to 0.78).

Conclusions

In this study, the previously reported association of TAK with HLA-B*52 in other populations was confirmed in patients from Turkey. The functional relevance of HLA-B*52 in TAK pathogenesis needs to be explored further.
Evaluation of the interaction potential of synthetic ethylene glycol compounds with nuclear Factor ï«B
Authors: Narasimhan Srinivasan , Majdalawieh Amin F. , Abu-Yousef Imad A. , Shanmugarajan Dhivya , Ramasubramanian Vishvanathan 
Published: September 2013

Â In the last three decades, nuclear factor ï«B (NF-ï«B) has been the focus of many researchers who are interested in understanding the various molecular mechanisms involved in inflammatory diseases and cancer. Interference with NF-ï«B activity can cause many cellular abnormalities including tumorigenesis. In this study, we focus on examining the potential of ten synthetic ethylene glycol based compounds to interact with the binding site of NF-ï«B. Computational analysis reveals that the ethylene glycol compounds examined in this study display differential ability to interact with NF-ï«B. Parameters such as ALOGP, dock score, and internal energy were determined for each of the studied compounds. Seven compounds were found to interact with specific amino acid residues within the binding site of NF-ï«B. The specific amino acids involved in the interaction were mapped and the nature of interaction was identified. Since NF-ï«B is implicated in the development of many inflammatory and immune-related conditions including cancer, we predict that the ethylene glycol compounds examined in this study can be targeted for the development of therapeutic agents that can be employed in the prevention and/or treatment of various diseases including cancer.
Selective Catalytic Oxidation of Alcohols, Aldehydes, Alkanes and Alkenes Employing Manganese Catalysts and Hydrogen Peroxide
Authors: Saisaha Pattama , Buettner Lea , van der Meer Margarethe , Hage Ronald , Feringa Ben L. , Browne Wesley R. , de Boer Johannes W. 
Published: September 2013

AbstractThe manganese‐containing catalytic system [MnIV,IV2O3(tmtacn)2]2+ (1)/carboxylic acid (where tmtacn=N,N′,N′′‐trimethyl‐1,4,7‐triazacyclononane), initially identified for the cis‐dihydroxylation and epoxidation of alkenes, is applied for a wide range of oxidative transformations, including oxidation of alkanes, alcohols and aldehydes employing H2O2 as oxidant. The substrate classes examined include primary and secondary aliphatic and aromatic alcohols, aldehydes, and alkenes. The emphasis is not primarily on identifying optimum conditions for each individual substrate, but understanding the various factors that affect the reactivity of the Mn‐tmtacn catalytic system and to explore which functional groups are oxidised preferentially. This catalytic system, of which the reactivity can be tuned by variation of the carboxylato ligands of the in situ formed [MnIII,III2(O)(RCO2)2(tmtacn)2]2+ dimers, employs H2O2 in a highly atom efficient manner. In addition, several substrates containing more than one oxidation sensitive group could be oxidised selectively, in certain cases even in the absence of protecting groups.magnified image
One Substrate – Seven Products with Different Prenylation Positions in One‐Step Reactions: Prenyltransferases Make it Possible
Authors: Fan Aili , Li Shu‐Ming 
Published: September 2013

AbstractPrenylated indole alkaloids derived from L‐tryptophan are widely distributed in nature and show diverse biological and pharmacological activities, usually distinct from their non‐prenylated precursors. Prenyltransferases catalyze the transfer reactions of prenyl moieties onto the indole nucleus and contribute largely to the structural diversity of these compounds. In this study, we demonstrate the acceptance of cyclo‐L‐homotryptophan‐D‐valine, an unnatural cyclic dipeptide, by eight prenyltransferases of the dimethylallyltryptophan synthase superfamily. Seven products with one prenyl moiety at each position of the indole nucleus and one diprenylated derivative were isolated from enzyme assays of cyclo‐L‐homotryptophan‐D‐valine with dimethylallyl diphosphate. To the best of our knowledge, this is the first report for production of seven monoprenylated products from one substrate by one‐step reactions.magnified image
Engineering of a Cytidine 5′‐Monophosphate‐Sialic Acid Synthetase for Improved Tolerance to Functional Sialic Acids
Authors: Yi Dong , He Ning , Kickstein Michael , Metzner Julia , Weiß Martin , Berry Alan , Fessner Wolf‐Dieter 
Published: September 2013

AbstractSialic acid‐containing glycoconjugates at the cell surface are of high importance in carbohydrate‐mediated recognition phenomena in physiological and pathological events, as well as in bacterial or viral infection. A key step in the enzymatic synthesis of natural sialoconjugates and functional synthetic analogues is the activation of sialic acids to cytidine 5′‐monophosphate (CMP)‐sialic acid intermediates catalyzed by CMP‐sialic acid synthetase (CSS). Based on our recently developed aligned protein model of substrate binding and a simple colorimetric screening assay, we have engineered the CSS from Neisseria meningitidis by structure‐guided site‐specific saturation mutagenesis at positions 192/193 to generate enzymes with broadened substrate scope. Top hits, including the F192S/F193Y variant, display an improvement of up to 70‐fold catalytic efficiency relative to wild‐type CSS for the conversion of sterically demanding N‐acyl modified sialic acid analogues, without compromising protein stability. Such significantly enhanced substrate capacity is a major step forward to realizing a generalized chemo‐enzymatic strategy for the efficient preparation of neo‐sialoconjugate libraries, demonstrated by the highly efficient, regio‐ and stereospecific synthesis of 2,6‐sialyllactose analogues by enzymatic coupling to the highly substrate tolerant α2,6‐sialyltransferase from Photobacterium leiognathi JT‐SHIZ‐145. Our results further document the unusual versatility of the N. meningitidis CSS and engineered variants for a common synthetic approach to sialoconjugates comprising a large diversity of natural and non‐natural sialic acid forms without the need for post‐synthetic enzymatic modification.magnified image
Retailer Motivation to Adjust Milk Prices: An Analysis Using Superelasticity of Demand
Authors: Hovhannisyan Vardges , Bozic Marin 
Published: September 2013

ABSTRACTSuperelasticity of demand offers a quantitative measure of demand curvature which is an important consideration in firm pricing decisions. We derive superelasticity analytic formulations for logit and random coefficient logit (RCL) demand models that can be used to shed light on firm incentives to alter price, firm cost pass‐through, and market power potential. We use the RCL superelasticities that are obtained via simulated generalized method of moments (GMM) to examine retail market power potential in regards to the marketing of national and store‐brand milk in the U.S. Our findings show that elasticity of demand rises in price for both brands, with elasticity for store brand milk lagging behind that for national brand in magnitude. Similarly, elasticities for national brands tend to decrease faster when prices are on the decline. Such a condition suggests that retailers can identify a pricing position, possibly in relation to national brand prices, at which there is a low incentive to increase or reduce store brand prices. [JEL Codes: D22, L13.]
Combating Multidrug‐Resistant Bacteria: Current Strategies for the Discovery of Novel Antibacterials
Authors: O'Connell Kieron M. G. , Hodgkinson James T. , Sore Hannah F. , Welch Martin , Salmond George P. C. , Spring David R. 
Published: September 2013

AbstractThe introduction of effective antibacterial therapies for infectious diseases in the mid‐20th century completely revolutionized clinical practices and helped to facilitate the development of modern medicine. Many potentially life‐threatening conditions became easily curable, greatly reducing the incidence of death or disability resulting from bacterial infections. This overwhelming historical success makes it very difficult to imagine life without effective antibacterials; however, the inexorable rise of antibiotic resistance has made this a very real and disturbing possibility for some infections. The ruthless selection for resistant bacteria, coupled with insufficient investment in antibacterial research, has led to a steady decline in the efficacy of existing therapies and a paucity of novel structural classes with which to replace them, or complement their use. This situation has resulted in a very pressing need for the discovery of novel antibiotics and treatment strategies, the development of which is likely to be a key challenge to 21st century medicinal chemistry.
Aging of the flame‐retardant properties of polycarbonate and polypropylene protected by an intumescent coating
Authors: Duquesne Sophie , Jimenez Maude , Bourbigot Serge 
Published: September 2013

ABSTRACTFlame retardancy (FR) in polycarbonate (PC) and polypropylene (PP) was obtained through the application of an intumescent coating on the polymeric substrate. A better performance was obtained with PC, a char former and highly viscous polymer, compared to with PP. Indeed, whereas 61 μm was required to obtain good FR (by the UL94 V0 rating, in particular) in the case of PC, at least 158 μm needed to be used to give FR to PP. The aging of the coated materials induced by UV‐filtered light radiation was then studied. This exposure led to a decrease in the FR. This effect was more pronounced in the case of PP compared to that of PC. The decrease in the FR was attributed to a decrease in the adhesion of the coating on the polymeric substrate because of its suspected physical aging. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39566.
Influence of thermooxidative aging on the static and dynamic mechanical properties of long‐glass‐fiber‐reinforced polyamide 6 composites
Authors: Zuo Xiaoling , Zhang Kaizhou , Lei Yang , Qin Shuhao , Hao Zhi , Guo Jianbing 
Published: September 2013

ABSTRACTThe static and dynamic mechanical properties, thermal behaviors, and morphology of pure long‐glass‐fiber‐reinforced samples [polyamide 6 (PA6)/long glass fiber (LGF)] with different thermal exposure times at 160°C were studied by comparison with stabilized samples in this study. The aging mechanism of the PA6/LGF samples under heat and oxygen was studied with the methods of thermal Fourier transform infrared (FTIR), differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy (SEM), and so on. The results indicate that the static mechanical strength, melting temperature, and crystallization temperature decreased because of the decomposition of the macromolecular chain of PA6 resin and the debonding of the interface between the glass fibers and matrix. The glass‐transition temperature and crystallinity also increased and decreased, respectively, after aging. The macromolecular chain decomposition dominated in the subsequent aging process; this resulted in many sharp and brittle microcracks appearing on the surfaces of the aged samples, as shown by SEM and the FTIR spectra. The existence of stabilizers endowed the PA6/LGF composites with better retention of static and dynamic mechanical properties. The reason was that the metal ions of the copper salt antioxidant acted as an anti‐aging catalyst in the reinforced PA6 system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39594.