bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and purification of granule-associated proteins relevant for poly(3-hydroxybutyric acid) biosynthesis from methylotrophic bacteria relying on the serine pathway
Authors: Föllner C. G. , Babel W. , Steinbüchel A.
Published: October 2009

The poly(3-hydroxybutyric acid) (PHB) granules from eight methylotrophic bacteria that use the serine pathway were isolated in a sucrose gradient (1–2 M); these bacteria included members of the genus Methylobacterium, Mycoplana rubra, and PHB-leaky mutants of Methylobacterium rhodesianum. As shown by sodium dodecyl sulfate – polyacrylamide gel electrophoresis, the granules from all investigated methylotrophic strains revealed two major bands representing small proteins. An efficient purification procedure for these two low molecular weight proteins associated with the PHB granules was developed by solubilization of the proteins with Triton X-114 and affinity chromatography on Procion Blue-H-ERD.Key words: poly(3-hydroxybutyric acid), granule-associated proteins, methylotrophic bacteria.
The function ofackAandptagenes is necessary for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthesis in recombinantpha+Escherichia coli
Authors: Rhie Ho Gun , Dennis Douglas
Published: October 2009

In Escherichia coli carrying the poly(3-hydroxyalkanoate) (PHA) biosynthesis pathway on a plasmid (pha+), the function of the ackA (acetate kinase) and pta (phosphotransacetylase) genes is necessary for efficient incorporation of 3-hydroxyvalerate (3-HV) into the copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)). Recombinant pha+E. coli fadR atoC(Con) strains possessing mutations in ackA, pta, or both ackA and pta exhibited substantially reduced levels of 3-HV formation. Conversely, the same strains carrying the ackA gene on a multicopy plasmid exhibited an increase in 3-HV formation concomitant with a large increase in acetate kinase activity. However, if the strain possessing the multicopy ackA+plasmid was mutant at the pta locus, it lost the ability to incorporate significant amounts of 3-HV into P(3HB-co-3HV). In addition to the ackA pta pathway, there is an inducible activity that can also mediate the incorporation of 3-HV into P(3HB-co-3HV). This pathway is repressed by glucose and is not normally operative in P(3HB-co-3HV) production in recombinant pha+E. coli strains that are grown using glucose as the major carbon source. It appears likely that this activity is due to an inducible acetyl-CoA synthetase that converts propionate to propionyl-CoA.Key words: polyhydroxyalkanoates, acetate kinase, phosphotransacetylase, acetyl-CoA synthesis, propionyl-CoA synthesis.
Kinetics as a tool for polyhydroxyalkanoate production optimization
Authors: Braunegg G. , Lefebvre G. , Renner G. , Zeiser A. , Haage G. , Loidl-Lanthaler K.
Published: October 2009

The increasing commercial importance of polyhydroxyalkanoates calls for the development of new, more efficient production processes. This can only be achieved by considering the kinetics of polyhydroxyalkanoate accumulation in fermentors, but efforts in this area have been few. In a 10-L fed-batch fermentor, Alcaligenes eutrophus G+3was used to produce poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) from glucose and γ-butyrolactone, and a strain of Alcaligenes latus was used to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose and propionate. After 83 h of fermentation, 9.26 g∙L−1of A. eutrophus contained 77.8% in mass of a copolymer with 7.9 mol% 4HB. The observed maximum specific growth rate (μmax) was 0.19 h−1for the residual biomass. Alcaligenes latus grew at an observed residual-biomass μmaxof 0.41 h−1and after 33.75 h had produced 6.6 g∙L−1of dry biomass with 72% of a copolymer with 28 mol% 3-hydroxyvalerate. Yields and specific substrate consumption and product formation rates were calculated. Examination of these results and of data found in the literature led to the proposition that for certain polyhydroxyalkanoate production processes, a multi-stage system consisting of a continuous stirred-tank fermentor in series with a plug-flow tubular reactor would be the most productive solution.Key words: polyhydroxyalkanoate, Alcaligenes latus, Alcaligenes eutrophus, kinetics, optimization.
Structural determinants defining common stereoselectivity of lipases toward secondary alcohols
Authors: Cygler Miroslaw , Grochulski Pawel , Schrag Joseph D.
Published: October 2009

In this review we summarize some aspects of the enantiopreference of the lipase from Candida rugosa following structural analysis of complexes of this lipase with two enantiomers of an analog of a tetrahedral intermediate in the hydrolysis of simple esters. The analysis of the molecular basis of the enantiomeric differentiation suggests that these results can be generalized to a large class of lipases and esterases. We also summarize our experiments on identification of the key regions in the lipases from Geotrichum candidum lipase responsible for differentiation between fatty acyl chains.Key words: lipases, stereoselectivity, three-dimensional structure, conformational rearrangement.
Polymer blends based on bacterial poly(3-hydroxybutyrate)
Authors: Scandola Mariastella
Published: October 2009

The phase behavior of blends of bacterial poly(3-hydroxybutyrate) (PHB) with highly substituted cellulose esters (CEs), polymethylmethacrylate (PMMA), polycyclohexylmethacrylate (PCHMA), ethylcellulose (EtC), and polyepichlorohydrin (PEC) is discussed on the basis of dynamic mechanical, calorimetric, and optical microscopy results. PHB is miscible in the melt in all proportions with CEs and PEC, is partially miscible with PMMA, and is totally immiscible with EtC and PCHMA. The rate and extent of biodegradation in activated sludge of immiscible PHB–EtC blends strongly depends on phase distribution, which is in turn dictated by composition and blending conditions. Miscible PHB–CE and PHB–PEC blends containing 80% PHB show analogous spherulitic morphology, but behave very differently in activated sludge. The blend containing PEC shows weight loss and surface erosion upon sludge exposure, whereas the one containing CE does not biodegrade over a period of 12 months. It is suggested that mobility of the amorphous mixed phase is an important parameter in determining biodegradability of miscible PHB-based blends.Key words: poly(3-hydroxybutyrate), blends, miscibility, biodegradation, morphology.
Blends containing poly(hydroxybutyrate-co-12%-hydroxyvalerate) and thermoplastic starch
Authors: Verhoogt H. , St-Pierre N. , Truchon F. S. , Ramsay B. A. , Favis B. D. , Ramsay J. A.
Published: October 2009

Poly(hydroxyalkanoates) form biodegradable composites when blended with starch granules but the mechanical properties are poor. Unlike starch granules, thermoplastic starch is a flexible material that can be reprocessed at elevated temperatures. Mixing thermoplastic starch with poly(hydroxybutyrate-co-12%-hydroxyvalerate) resulted in a true blend in which the starch phase was also deformed. Nevertheless, the blends were still brittle despite the presence of the flexible starch phase. Morphological studies showed that the shapes of the dispersed phases in these blends were irregular and that the sizes were large owing to a large difference in viscosity between the two phases in the melt and inadequate shear during processing. Thermal analysis of the blends and starting polymers showed no indication of any interaction between the two polymers. Even if there is no compatibility between the two phases, improved mechanical properties may be obtained by optimizing the blend morphology during processing.Key words: P(HB-co-12%-HV), thermoplastic starch, blends.
GENERALIZED ANALYSIS OF ELECTRICAL CIRCUITS BY USING HYPERNION MATRICES
Authors: BERKOVICH YEFIM , SHENKMAN ARIEH , TAPUCHI SAAD
Published: October 2009

In this paper a novel method for circuit analysis is proposed. It is based on using symbolic analysis in matrix form, which is especially appropriate for repetitive similar calculations of the same circuit. This method, which applies hyper-complex numbers (hypernions), was first developed by the authors for analyzing the non-sinusoidal operation of electrical circuits. Now, the method has been extended to the analysis of electronic/switching circuits in which the sources and/or the parameters are step-wisely changed as a result of switching. Such circuits are common in different kinds of DC-DC converters (such as Buck, Boost, Cuk, etc.). The proposed method gives a new approach to the analysis of the above circuits by opening the possibility of treating them in a general-analytical form, just like in regular electrical circuits having a constant configuration and constant parameters. The computation of such kinds of circuits by using the proposed method becomes very simple, since the circuit does not have to be analyzed many times, each time for a different configuration, but all at once by performing a parallel computation. The theoretical presentation is accompanied by numerical examples.
LEAKAGE POWER REDUCTION THROUGH DUAL Vth ASSIGNMENT CONSIDERING THRESHOLD VOLTAGE VARIATION
Authors: WANG YU , SHEN XUKAI , LUO RONG , YANG HUAZHONG
Published: October 2009

With technology scaling, leakage power has become an important part of the total power consumption, affecting both yields and lifetime of digital circuits. Dual V th assignment, which was an effective method to reduce leakage power in the past, is also effective in today's technologies with certain modifications. In this paper, based on our statistical timing analysis (SSTA) framework, we presented a dual V th assignment method which can effectively reduce the leakage power even in the presence of large V th variation. Besides, taking the correlation between gates into account, we propose a novel statistical DAG pruning method to speed up the dual V th assignment algorithm. Experimental results show that statistical dual V th assignment can reduce on average 95% and 40% more leakage current compared with the conventional static method, without affecting the performance constraints under 180 nm and 90 nm technology nodes. Also our statistical DAG pruning method can reduce 30% gates in the circuit on average and save up to 50% of the total runtime in the 90 nm technology node.
POWER CONSUMPTION REDUCTION IN A VITERBI DECODER FOR OFDM-WLAN
Authors: ANGARITA FABIAN , CANET M. JOSE , SANSALONI TRINIDAD , ALMENAR VICENC , VALLS JAVIER
Published: October 2009

WLAN standards make use of different transmission modes to cope with different channel conditions, these modes make use of different modulation constellations and code rates. Data encoding is done with a 64-state convolutional code of rate 1/2, some modes employ this basic rate and others puncture the encoded data to obtain a rate of 3/4. At the receiver, the decision depth needed by the Viterbi decoder is higher for decoding punctured modes than for decoding non-punctured modes, this means that punctured modes need a greater area and, then, they cause a higher power consumption. This fact is used in this letter to reduce the power consumption of the Viterbi decoder when dealing with half-rate code modes, an architecture that disables the unnecessary hardware in the non-punctured modes allows a reduction of 20% in the dynamic power consumption with an area increase of only 1%.
LOW-LYING $\frac52^{+}$ RESONANCE IN 11Be: BOUND STATE IN THE CONTINUUM
Authors: MAHAPATRA SABYASACHI , DAS TAPAN KUMAR , DUTTA SAGAR KUMAR
Published: October 2009

We have used a novel theoretical technique to calculate the [Formula: see text] resonance state of 11 Be using a two-body model (10 Be+n ). The effective two-body potential for the system has a shallow well followed by a low and very wide barrier causing numerical difficulties in the calculation of low-lying resonances. Using supersymmetric quantum mechanics (SSQM), one can construct an isospectral potential with a bound state in the continuum (BIC). This isospectral potential has a deep well and high barrier which can effectively trap the system giving rise to a BIC. Our calculated resonance energy of the [Formula: see text] state of 11 Be matches extremely well with the experimental value. Calculated width of the resonance also agrees within the computational error bars.
THE EFFECT OF SURFACE NUCLEON DENSITY ON THE TOTAL POTENTIAL OF DI-NUCLEAR SYSTEMS
Authors: GHODSI O. N. , MAHMOODI M. , ARIAI J.
Published: October 2009

The effect of the density of the surface nucleons on the calculation of the total potential in reactions where the participant nuclei are on the stability line and at least one of the participant nuclei is rich in neutrons has been studied. The results obtained by the analysis of the 16 O +209 Bi , 16 O +144 Nd , and 16 O +144 Sm reactions using the Hartree–Fock calculations of the neutron and the proton densities show a decrease of about 0.67, 0.53, and 0.45 MeV of the fusion barrier height in comparison to the corresponding values obtained when the nuclear density is taken to be proportional to the nuclear charge. It is shown that this decrease is due to the variation of the ratio of the density of neutrons to that of the protons in outer regions of the nuclear densities of 209 Bi , 144 Nd , and 144 Sm nuclei.
OFF-SHELL TWIST-FOUR PHOTON LIGHT-CONE WAVEFUNCTION FOR THE CHIRALITY-CONSERVING QUARK–ANTIQUARK VECTOR CURRENT IN THE LOW-ENERGY EFFECTIVE THEORY OF QCD
Authors: LI MINGHAI , LIU JUEPING
Published: October 2009

Within the framework of the low-energy effective theory arising from the instanton vacuum model of QCD, the twist-four virtual photon wavefunction, gγ3(u, P2), corresponding to the nonlocal quark–antiquark vector current is calculated at the low-energy scale. The coupling constant, fγ(P2), of the quark–antiquark vector current to the virtual photon state is also obtained. The behavior of the coupling as well as the obtained photon wave function especially at the end points is discussed.
MINING SIMPLIFIED FUZZY IF-THEN RULES FOR PATTERN CLASSIFICATION
Authors: HU YI-CHUNG , TSENG FANG-MEI
Published: October 2009

A fuzzy if-then rule whose consequent part is a real number is referred to as a simplified fuzzy rule. Simplified fuzzy if-then rules have been widely used in function approximation problems due to no complicated defuzzification is required. The proposed simplified fuzzy rule-based classification system, whose number of output is equal to the number of different classes, approximates an unknown mapping from input to desired output for each discriminant function. Not only a fuzzy data mining method is proposed to find simplified fuzzy if-then rules from training data, but also the genetic algorithm is employed to determine some user-specified parameters. To evaluate the classification performance of the proposed method, computer simulations are performed on some well-known datasets, showing that the generalization ability of the proposed method is comparable to the other fuzzy or nonfuzzy methods.
PATTERN RECOGNITION OF LONGITUDINAL TRIAL DATA WITH NONIGNORABLE MISSINGNESS: AN EMPIRICAL CASE STUDY
Authors: FANG HUA , ESPY KIMBERLY ANDREWS , RIZZO MARIA L. , STOPP CHRISTIAN , WIEBE SANDRA A. , STROUP WALTER W.
Published: October 2009

Methods for identifying meaningful growth patterns of longitudinal trial data with both nonignorable intermittent and drop-out missingness are rare. In this study, a combined approach with statistical and data mining techniques is utilized to address the nonignorable missing data issue in growth pattern recognition. First, a parallel mixture model is proposed to model the nonignorable missing information from a real-world patient-oriented study and concurrently to estimate the growth trajectories of participants. Then, based on individual growth parameter estimates and their auxiliary feature attributes, a fuzzy clustering method is incorporated to identify the growth patterns. This case study demonstrates that the combined multi-step approach can achieve both statistical generality and computational efficiency for growth pattern recognition in longitudinal studies with nonignorable missing data.
DECISION MAKING ON STRATEGIC ENVIRONMENTAL TECHNOLOGY LICENSING: FIXED-FEE VERSUS ROYALTY LICENSING METHODS
Authors: CHANG MING-CHUNG , HU JIN-LI , TZENG GWO-HSHIUNG
Published: October 2009

Because of a deterioration in the quality of the environment, this paper studies the effects of the environment and the economy on environmental technology licensing in a homogeneous Cournot duopoly model in order to reduce environmental pollution and hence improve social welfare. To this end, two licensing methods — namely, a fixed-fee licensing method and a royalty licensing method — are compared. It is found that a high emission tax rate induces the innovator to not license the environmental technology to the licensee under the fixed-fee licensing method. As for social welfare, a large innovation scale of environmental technology does not guarantee that social welfare will be maximized. Finally, a large innovation scale of environmental technology is likely to increase consumer surplus if the marginal environmental damage is significant. Consumers are likely to prefer royalty licensing to fixed-fee licensing. This conclusion differs from Wang's finding in 2002.
iVisit agitating for the evolution of fixed-mobile tele-presence and augmented reality
Authors: Dialameh Orang
Published: October 2009

A short overview of the history of video conferencing shows the evolution of this tech and its slow adoption...
Invigorating the future internet debate
Authors: Trossen Dirk
Published: October 2009

While many initiatives have been discussing the future of the Internet, the EIFFEL1 think tank set out to push these discussions forward by assembling a community of researchers debating the potential thrusts towards the Future Internet. This article provides an account of these discussions, being addressed both to the EIFFEL membership and more widely to members of the community interested in medium to long-term developments. We outline immediate problems as well as potentially missed opportunities in the current Internet, while focussing the debate on the need for a Future Internet on the style we conduct research as well as how we design systems at large. Most importantly, we recognize that an inter-disciplinary dialogue is required to formulate actions to be taken and to remove barriers to their realization.
Yet another access point
Authors: Gass Richard , Diot Christophe
Published: October 2009

Increasing popularity in personal access points and travel routers has begun to rise with the advent of smaller and more battery conscious devices. This article introduces the YAAP (Yet Another Access Point), an open source software that enables ad-hoc infrastructure services in the absence of network connectivity. The YAAP provides a familiar way to connect users to each other and provides a set of useful services. We list and describe its applications, explain how it can be used, provide details about the code, and readers to where it can be downloaded.
The semantics of power and ARM multiprocessor machine code (abstract only)
Authors: Alglave Jade , Fox Anthony , Ishtiaq Samin , Myreen Magnus O. , Sarkar Susmit , Sewell Peter , Nardelli Francesco Zappa
Published: October 2009

We develop a rigorous semantics for Power and ARM multiprocessor programs, including their relaxed memory model and the behaviour of reasonable fragments of their instruction sets. The semantics is mechanised in the HOL proof assistant. This should provide a good basis for informal reasoning and formal verification of low-level code for these weakly consistent architectures, and, together with our x86 semantics, for the design and compilation of high-level concurrent languages.
Low-pain, high-gain multicore programming in Haskell
Authors: Al Zain Abdallah Deeb I. , Hammond Kevin , Berthold Jost , Trinder Phil , Michaelson Greg , Aswad Mustafa
Published: October 2009

With the emergence of commodity multicore architectures, exploiting tightly-coupled parallelism has become increasingly important. Functional programming languages, such as Haskell, are, in principle, well placed to take advantage of this trend, offering the ability to easily identify large amounts of fine-grained parallelism. Unfortunately, obtaining real performance benefits has often proved hard to realise in practice.

This paper reports on a new approach using middleware that has been constructed using the Eden parallel dialect of Haskell. Our approach is "low pain" in the sense that the programmer constructs a parallel program by inserting a small number of higher-order algorithmic skeletons at key points in the program. It is "high gain" in the sense that we are able to get good parallel speedups. Our approach is unusual in that we do not attempt to use shared memory directly, but rather coordinate parallel computations using a message-passing implementation. This approach has a number of advantages. Firstly, coordination, i.e. locking and communication, is both confined to limited shared memory areas, essentially the communication buffers, and is also isolated within well-understood libraries. Secondly, the coarse thread granularity that we obtain reduces coordination overheads, so locks are normally needed only on (relatively large) messages, and not on individual data items, as is often the case for simple shared-memory implementations. Finally, cache coherency requirements are reduced since individual tasks do not share caches, and can garbage collect independently.

We report results for two representative computational algebra problems. Computational algebra is a challenging application area that has not been widely studied in the general parallelism community. Computational algebra applications have high computational demands, and are, in principle, often suitable for parallel execution, but usually display a high degree of irregularity in terms of both task and data structure. This makes it difficult to construct parallel applications that perform well in practice. Using our system, we are able to obtain both extremely good processor utilisation (97%) and very good absolute speedups (up to 7.7) on an eight-core machine.
Declarative aspects of memory management in the concurrent collections parallel programming model (abstract only)
Authors: Budimlic Zoran , Chandramowlishwaran Aparna M. , Knobe Kathleen , Lowney Geoff N. , Sarkar Vivek , Treggiari Leo
Published: October 2009

Concurrent Collections (CnC) is a declarative parallel language that allows the application developer to express their parallel application as a collection of high-level computations called steps that communicate via single-assignment data structures called items.

A CnC program is specified in two levels. At the bottom level, an existing imperative language implements the computations within the individual computation steps. At the top level, CnC describes the relationships (ordering constraints) among the steps. The memory management mechanism of the existing imperative language manages data whose lifetime is within a computation step. A key limitation in the use of CnC for long-running programs is the lack of memory management and garbage collection for data items with lifetimes that are longer than a single computation step. Although the goal here is the same as that of classical garbage collection, the nature of problem and therefore nature of the solution is distinct. The focus of this paper is the memory management problem for these data items in CnC.

We introduce a new declarative slicing annotation for CnC that can be transformed into a reference counting procedure for memory management. Preliminary experimental results obtained from a Cholesky example show that our memory management approach can result in space reductions for CnC data items of up to 28x relative to the baseline case of standard CnC without memory management.
NASA's TReK project
Authors: Hendrix T. Dean , Schneider Michelle P.
Published: October 2009

Software development projects face numerous challenges that threaten their successful completion. Whether it is not enough money, too little time, or a case of "requirements creep" that turns into a full sprint, projects must meet these challenges or face possible disastrous consequences. The funds needed to purchase supporting software tools or computing hardware may not be available, or they may be available for so short a period that informed purchase decisions become infeasible. Personnel resources are often limited, and it is difficult to adjust to personnel fluctuations during the project. The composition of the team personnel also offers potential challenges. A new software development team may begin with some members unfamiliar with the software development environment and project tools, and their learning curve can affect early productivity.
Securing PC applications
Authors: Zviran Moshe
Published: October 2009

The widespread use of personal computers and the growth of end-user computing have introduced a myriad of security concerns. As PC-based information systems become readily available and more individuals become computer literate, the risk of ill-intentioned individuals obtaining unauthorized access to computing resources and violating the secrecy and integrity of data increases significantly. But many of these computer security concerns for PCs remain largely unaddressed [6].
Airway surface liquid depth measured in ex vivo fragments of pig and human trachea: dependence on Na+ and Cl− channel function
Authors: Song Yuanlin , Namkung Wan , Nielson Dennis W. , Lee Jae-Woo , Finkbeiner Walter E. , Verkman A. S.
Published: October 2009

The airway surface liquid (ASL) is the thin fluid layer lining the airways whose depth may be reduced in cystic fibrosis. Prior measurements of ASL depth have been made in airway epithelial cell cultures. Here, we established methodology to measure ASL depth to ∼1-μm accuracy in ex vivo fragments of freshly obtained human and pig tracheas. Airway fragments were mounted in chambers designed for perfusion of the basal surface and observation of the apical, fluorescently stained ASL by scanning confocal microscopy using a high numerical aperture lens immersed in perfluorocarbon. Measurement accuracy was verified using standards of specified fluid thickness. ASL depth in well-differentiated primary cultures of human nasal respiratory epithelium was 8.0 ± 0.5 μm (SE 10 cultures) under basal conditions, 8.4 ± 0.4 μm following ENaC inhibition by amiloride, and 14.5 ± 1.2 μm following CFTR stimulation by cAMP agonists. ASL depth in human trachea was 7.0 ± 0.7 μm under basal conditions, 11.0 ± 1.7 μm following amiloride, 17.0 ± 3.4 μm following cAMP agonists, and 7.1 ± 0.5 μm after CFTR inhibition. Similar results were found in pig trachea. This study provides the first direct measurements of ASL depth in intact human airways and indicates the involvement of ENaC sodium channels and CFTR chloride channels in determining ASL depth. We suggest that CF lung disease may be caused by the inability of CFTR-deficient airways to increase their ASL depth transiently following secretory stimuli that in non-CF airways produce transient increases in ASL depth.
Short-Latency Crossed Inhibitory Responses in the Human Soleus Muscle
Authors: Stubbs Peter W. , Mrachacz-Kersting Natalie
Published: October 2009

Even though interlimb coordination is critical in bipedal locomotion, the role of muscle afferent mediated feedback is unknown. The aim of this study was to establish if ipsilateral muscle generated afferent feedback can influence contralateral muscle activation patterns in the human lower limb and to elucidate the mechanisms involved. The effect of ipsilateral tibial nerve stimulation on contralateral soleus (cSOL) responses were quantified. Three interventions were investigated, 1) electrical stimulation applied to the tibial nerve at stimulation intensities from 0 to 100% of maximal M-wave (M-max) with the cSOL contracted from 5 to 15% of maximal voluntary contraction (MVC) and 15 to 30% MVC, 2) ispsilateral tibial nerve stimulation at 75% M-max prior to, during, and following the application of ischemia to the ipsilateral thigh. 3) Electrical stimulation applied to the ipsilateral sural (SuN) and medial plantar nerves at stimulation intensities from 1 to 3 times perceptual threshold. A short-latency depression in the cSOL electromyogram (EMG; onset: 37–41 ms) was observed following ipsilateral tibial nerve stimulation. The magnitude of this depression increased ( P = 0.0005 and P = 0.000001) with increasing stimulus intensities. Ischemia delayed the time of the minimum of the cSOL depression ( P = 0.04). SuN and medial plantar nerve stimulation evoked a longer latency depression [average; 91.2 ms (SuN); 142 ms (medial plantar nerve)] and therefore do not contribute to the response. This is the first study to demonstrate a short-latency depression in the cSOL following ipsilateral tibial nerve stimulation. Due to its short latency, the response is spinally mediated. The involvement of crossed spinal interneurons receiving input from low-threshold muscle afferents is discussed.
Oligodendrocyte Development and Myelin Biogenesis: Parsing Out the Roles of Glycosphingolipids
Authors: Jackman Nicole , Ishii Akihiro , Bansal Rashmi
Published: October 2009

The myelin sheath is an extension of the oligoddendrocyte (OL) plasma membrane enriched in lipids that ensheaths the axons of the central and peripheral nervous system. Here, we review the involvement of glycosphingolipids in myelin/OL functions, including the regulation of OL differentiation, lipid raft-mediated trafficking and signaling, and neuronglia interactions.
Influences of Tip Cooling Injection on Tip Clearance Control at Design and Off‐Design Incidences
Authors: Niu Maosheng , Zang Shusheng
Published: October 2009

A numerical investigation has been performed to study the influences of cooling injection from the blade tip surface on controlling tip clearance flow in an unshrouded, high‐turning axial turbine cascade. Emphasis is put on the analysis of the effectiveness of tip injection when the approaching flow is at design and off‐design incidences. A total of three incidence angles are investigated, −7.4°, 0°, 0°, 0°, and 7.6°, 0° relative to the design value. The results indicate that even at the off‐design incidences, tip injection can also act as an obstruction to the tip clearance flow and weaken the interaction between the passage flow and the tip clearance flow. It is also found that tip injection causes the tip clearance loss to be less sensitive to the incidences. Moreover, with injection, at all these incidences the heat transfer conditions are improved significantly on the blade tip surface in the middle and aft parts of blade. Thus, tip injection is proved to be an effective method of controlling tip clearance flow, even at off‐design conditions. Beside that, an indirect empirical correlation is observed to be able to perform well in predicting the losses induced by tip clearance flow at design and off‐design conditions, no matter whether air injection is active or not.
Manual Testicular Detorsion under Propofol Sedation
Authors: Harvey Martyn , Chanwai Giles , Cave Grant
Published: October 2009

Acute spermatic cord torsion is a urologic emergency requiring accurate diagnosis and timely intervention to effect testicular salvage. We report a case of adolescent testicular torsion successfully reduced following manual detorsion under sedation at the Emergency Department. Scrotal exploration and bilateral orchidopexy were subsequently performed as a semielective procedure.
Fractional Regularization Term for Variational Image Registration
Authors: Verdú-Monedero Rafael , Larrey-Ruiz Jorge , Morales-Sánchez Juan , Sancho-Gómez José Luis
Published: October 2009

Image registration is a widely used task of image analysis with applications in many fields. Its classical formulation and current improvements are given in the spatial domain. In this paper a regularization term based on fractional order derivatives is formulated. This term is defined and implemented in the frequency domain by translating the energy functional into the frequency domain and obtaining the Euler‐Lagrange equations which minimize it. The new regularization term leads to a simple formulation and design, being applicable to higher dimensions by using the corresponding multidimensional Fourier transform. The proposed regularization term allows for a real gradual transition from a diffusion registration to a curvature registration which is best suited to some applications and it is not possible in the spatial domain. Results with 3D actual images show the validity of this approach.
A Note on the Properties of Generalised Separable Spatial Autoregressive Process
Authors: Shitan Mahendran , Peiris Shelton
Published: October 2009

Spatial modelling has its applications in many fields like geology, agriculture, meteorology, geography, and so forth. In time series a class of models known as Generalised Autoregressive (GAR) has been introduced by Peiris (2003) that includes an index parameter δ. It has been shown that the inclusion of this additional parameter aids in modelling and forecasting many real data sets. This paper studies the properties of a new class of spatial autoregressive process of order 1 with an index. We will call this a Generalised Separable Spatial Autoregressive (GENSSAR) Model. The spectral density function (SDF), the autocovariance function (ACVF), and the autocorrelation function (ACF) are derived. The theoretical ACF and SDF plots are presented as three‐dimensional figures.
Determinants and Correlation of Systemic and Cervical Concentrations of Total IgA and IgG
Authors: Safaeian Mahboobeh , Kemp Troy , Falk Roni T. , Rodriguez Ana Cecilia , Hildesheim Allan , Williams Marcus , Porras Carolina , Herrero Rolando , Pinto Ligia A.
Published: October 2009

We compared systemic and cervical total IgA and IgG during the menstrual cycle among 154 women who attended clinic visits at follicular/early, periovulatory/mid, and luteal/late phases of menstrual cycle. Paired serum and cervical secretions were tested at each visit for total IgA and IgG using ELISA. Geometric mean titers for systemic IgA and IgG were 1.92 and 8.25 mg/mL, respectively. There were no differences in titers by menstrual cycle phase, neither were they correlated to cervical titers (ρ = 0.17 and 0.16, respectively). The lack of correlation between systemic and cervical total IgA and IgG suggests that systemic concentrations are not reflective of cervical levels. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2672–6)
Chromosome 3p12.3-p14.2 and 3q26.2-q26.32 Are Genomic Markers for Prognosis of Advanced Nasopharyngeal Carcinoma
Authors: Sheu Jim Jinn-Chyuan , Lee Chia-Huei , Ko Jenq-Yuh , Tsao George S.W. , Wu Chung-Chun , Fang Chih-Yeu , Tsai Fuu-Jen , Hua Chun-Hung , Chen Chi-Long , Chen Jen-Yang
Published: October 2009

Purpose: Nasopharyngeal carcinoma is an epithelial malignancy with a remarkable racial and geographic distribution. Previous cytogenetic studies have shown nasopharyngeal carcinoma to be characterized by gross genomic aberrations. However, identification of susceptible gene loci in advanced nasopharyngeal carcinoma has been poorly discussed.

Experimental Design: A genome-wide survey of gene copy number changes was initiated with two nasopharyngeal carcinoma cell lines by array-based comparative genomic hybridization analysis. These alterations were confirmed by a parallel analysis with the data from the gene expression microarray and were validated by quantitative PCR. Clinical association of the defined target genes was analyzed by fluorescence in situ hybridization on 48 metastatic tumors.

Results: A high percentage of genes were consistently altered in dosage and expression levels with gain on 3q26.2-q26.32 and losses on 3p12.3-p14.2 and 9p21.3-p23. Six candidate genes, GPR160 (3q26.2-q27), SKIL (3q26), ADAMTS9 (3p14.2-p14.3), LRIG1 (3p14), MPDZ (9p22-p24), and ADFP (9p22.1) were validated by quantitative PCR. Fluorescence in situ hybridization studies revealed amplification of GPR160 (in 25% of cases) and SKIL (33%); and deletion of ADAMTS9 (30%), LRIG1 (35%), MPDZ (15%), and ADFP (15%). Clinical association analyses indicated a poor survival rate with genetic alterations at the defined 3p deletion (P = 0.0012) and the 3q amplification regions (P = 0.0114).

Conclusion: The combined microarray technologies suggested novel candidate oncogenes, amplification of GPR160 and SKIL at 3q26.2-q26.32, and deletion of tumor suppressor genes ADAMTS9 and LRIG1 at 3p12.3-p14.2. Altered expression of these genes may be responsible for malignant progression and could be used as potential markers for nasopharyngeal carcinoma. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2709–16)
Obesity and Cancer: The Role of Dysfunctional Adipose Tissue
Authors: van Kruijsdijk Rob C.M. , van der Wall Elsken , Visseren Frank L.J.
Published: October 2009

Overweight and obesity are health problems of epidemic proportions, increasing the risk not only of cardiovascular disease and type 2 diabetes mellitus but also of various types of cancer. Obesity is strongly associated with changes in the physiological function of adipose tissue, leading to insulin resistance, chronic inflammation, and altered secretion of adipokines. Several of these factors, such as insulin resistance, increased levels of leptin, plasminogen activator inhibitor-1, and endogenous sex steroids, decreased levels of adiponectin, and chronic inflammation, are involved in carcinogenesis and cancer progression. This article reviews these mechanisms, focusing on adipose tissue dysfunction as a unifying causal factor. Although understanding of the link between obesity and cancer might provide therapeutic targets, preventing overweight and obesity still remains number one priority. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2569–78)
Soy Intake is Associated with Increased 2-Hydroxylation and Decreased 16α-Hydroxylation of Estrogens in Asian-American Women
Authors: Fuhrman Barbara J. , Pfeiffer Ruth , Xu Xia , Wu Anna H. , Korde Larissa , Gail Mitchell H. , Keefer Larry K. , Veenstra Timothy D. , Hoover Robert N. , Ziegler Regina G.
Published: October 2009

Introduction: In Asian and Asian-American women, soy consumption is associated with reduced breast cancer risk, perhaps due to its effects on estrogen production or metabolism. In a sample of Asian-American women, we investigated the associations of usual adult soy intake with the urinary concentrations of 15 estrogens and estrogen metabolites (EM) measured using liquid chromatography-tandem mass spectrometry.

Methods: Participants included 430 Chinese-American, Japanese-American, and Filipino-American women, ages 20 to 55 years, and living in San Francisco-Oakland (California), Los Angeles (California), or Oahu (Hawaii). They were postmenopausal (n = 167) or premenopausal in luteal phase (n = 263) when 12-hour urine samples were collected. Robust linear regression was used to assess soy tertiles as predictors of log-transformed EM measures. Individual and grouped EM were considered as concentrations (pmol/mg creatinine) and as percentages of total EM (%EM).

Results: Factor analysis confirmed that EM groups defined by metabolic pathways appropriately captured covariation in EM profiles. Total EM concentrations were not significantly associated with soy in premenopausal or postmenopausal women. Among all women, %2-hydroxylated EM and %4-hydroxylation pathway EM were 16% higher (Ptrend = 0.02) and 19% higher (Ptrend = 0.03) in the highest versus lowest soy tertiles, respectively. In contrast, 16% hydroxylated EM were 11% lower (Ptrend < 0.01). Results were consistent across ethnic and menopausal groups and after adjustment for westernization measured by birthplace (Asia or United States).

Discussion: Findings suggest that regular soy intake is associated with increased ratios of 2:16-pathway EM and with higher relative levels of 4-hydroxylated EM. The observed variations in estrogen metabolism might modify breast cancer risk. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2751–60)
Occupational Exposure to High Molecular Weight Allergens and Lymphoma Risk Among Italian Adults
Authors: Mirabelli Maria C. , Zock Jan-Paul , D'Errico Angelo , Kogevinas Manolis , de Sanjosé Silvia , Miligi Lucia , Seniori Costantini Adele , Vineis Paolo
Published: October 2009

Objectives. Exposure to high molecular weight (HMW) allergens that provoke immune reactivity through an IgE-mediated pathway has been associated with a decreased risk of B-cell lymphoma. The present analysis was conducted to assess the associations between occupational exposure to specific HMW allergens and the risk of B-cell, T-cell, and Hodgkin's lymphomas.

Methods. We analyzed data from 2,290 incident lymphoma cases and 1,771 population-based controls enrolled in a multicenter study of hematolymphopoietic malignancies conducted in Italy between 1991 and 1993. All cases were histologically or cytologically confirmed. Controls were frequency-matched to cases based on age, sex, and study center. An industrial hygienist evaluated HMW occupational exposure classifications after an asthma-specific job exposure matrix was applied to participants' job histories. Unconditional logistic regression was used to assess associations between occupational exposures that occurred ≥10 years before the date of lymphoma diagnosis and B-cell, T-cell, and Hodgkin's lymphomas.

Results. Ten percent of cases and 11% of controls were occupationally exposed to HMW allergens. Exposed individuals had a decreased risk for all lymphomas combined (odds ratio, 0.78; 95% confidence interval, 0.63-0.97), particularly for B-cell lymphomas (odds ratio, 0.75; 95% confidence interval, 0.59-0.94). The decreased risks for all lymphomas were also observed when HMW allergen exposure was limited to animal and latex allergens.

Conclusions. These findings support the hypothesis that occupational exposure to immunologically active HMW allergens is inversely associated with the risk for lymphoma. The effect of exposure to specific allergens warrants further assessment. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2650–4)
Vitamin D Receptor Expression Is Associated with PIK3CA and KRAS Mutations in Colorectal Cancer
Authors: Kure Shoko , Nosho Katsuhiko , Baba Yoshifumi , Irahara Natsumi , Shima Kaori , Ng Kimmie , Meyerhardt Jeffrey A. , Giovannucci Edward L. , Fuchs Charles S. , Ogino Shuji
Published: October 2009

Vitamin D is associated with decreased risks of various cancers, including colon cancer. The vitamin D receptor (VDR) is a transcription factor, which plays an important role in cellular differentiation and inhibition of proliferation. A link between VDR and the RAS–mitogen-activated protein kinase (MAPK) or phosphatidylinositol 3-kinase (PI3K)–AKT pathway has been suggested. However, the prognostic role of VDR expression or its relationship with PIK3CA or KRAS mutation remains uncertain. Among 619 colorectal cancers in two prospective cohort studies, 233 (38%) tumors showed VDR overexpression by immunohistochemistry. We analyzed for PIK3CA and KRAS mutations and LINE-1 methylation by Pyrosequencing, microsatellite instability (MSI), and DNA methylation (epigenetic changes) in eight CpG island methylator phenotype (CIMP)–specific promoters [CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1] by MethyLight (real-time PCR). VDR overexpression was significantly associated with KRAS mutation (odds ratio, 1.55; 95% confidence interval, 1.11-2.16) and PIK3CA mutation (odds ratio, 2.17; 95% confidence interval, 1.36-3.47), both of which persisted in multivariate logistic regression analysis. VDR was not independently associated with body mass index, family history of colorectal cancer, tumor location (colon versus rectum), stage, tumor grade, signet ring cells, CIMP, MSI, LINE-1 hypomethylation, BRAF, p53, p21, β-catenin, or cyclooxygenase-2. VDR expression was not significantly related with patient survival, prognosis, or clinical outcome. In conclusion, VDR overexpression in colorectal cancer is independently associated with PIK3CA and KRAS mutations. Our data support potential interactions between the VDR, RAS–MAPK and PI3K–AKT pathways, and possible influence by KRAS or PIK3CA mutation on therapy or chemoprevention targeting VDR. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2765–72)
CYP19A1 Genetic Variation in Relation to Prostate Cancer Risk and Circulating Sex Hormone Concentrations in Men from the Breast and Prostate Cancer Cohort Consortium
Authors: Travis Ruth C. , Schumacher Fredrick , Hirschhorn Joel N. , Kraft Peter , Allen Naomi E. , Albanes Demetrius , Berglund Goran , Berndt Sonja I. , Boeing Heiner , Bueno-de-Mesquita H. Bas , Calle Eugenia E. , Chanock Stephen , Dunning Alison M. , Hayes Richard , Feigelson Heather Spencer , Gaziano J. Michael , Giovannucci Edward , Haiman Christopher A. , Henderson Brian E. , Kaaks Rudolf , Kolonel Laurence N. , Ma Jing , Rodriguez Laudina , Riboli Elio , Stampfer Meir , Stram Daniel O. , Thun Michael J. , Tjønneland Anne , Trichopoulos Dimitrios , Vineis Paolo , Virtamo Jarmo , Le Marchand Loïc , Hunter David J.
Published: October 2009

Sex hormones, particularly the androgens, are important for the growth of the prostate gland and have been implicated in prostate cancer carcinogenesis, yet the determinants of endogenous steroid hormone levels remain poorly understood. Twin studies suggest a heritable component for circulating concentrations of sex hormones, although epidemiologic evidence linking steroid hormone gene variants to prostate cancer is limited. Here we report on findings from a comprehensive study of genetic variation at the CYP19A1 locus in relation to prostate cancer risk and to circulating steroid hormone concentrations in men by the Breast and Prostate Cancer Cohort Consortium (BPC3), a large collaborative prospective study. The BPC3 systematically characterized variation in CYP19A1 by targeted resequencing and dense genotyping; selected haplotype-tagging single nucleotide polymorphisms (htSNP) that efficiently predict common variants in U.S. and European whites, Latinos, Japanese Americans, and Native Hawaiians; and genotyped these htSNPs in 8,166 prostate cancer cases and 9,079 study-, age-, and ethnicity-matched controls. CYP19A1 htSNPs, two common missense variants and common haplotypes were not significantly associated with risk of prostate cancer. However, several htSNPs in linkage disequilibrium blocks 3 and 4 were significantly associated with a 5% to 10% difference in estradiol concentrations in men [association per copy of the two-SNP haplotype rs749292-rs727479 (A-A) versus noncarriers; P = 1 × 10-5], and with inverse, although less marked changes, in free testosterone concentrations. These results suggest that although germline variation in CYP19A1 characterized by the htSNPs produces measurable differences in sex hormone concentrations in men, they do not substantially influence risk of prostate cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2734–44)