bluuebunny/crossref_metadata_2025 huggingface dataset:
‘To find oneself a partner’ vs. ‘to find a partner’
Authors: Ebeling Jarle , Oksefjell Ebeling Signe
Published: September 2013

This paper investigates the patterns V REFL NPindef and V NPindef in an English-Norwegian contrastive perspective. Both languages have a set of verbs that may enter into both patterns, as illustrated in the title by ‘find’ and in Norwegian by finne. On the basis of material drawn from the extended fiction version of the English-Norwegian Parallel Corpus, it can be established that the two languages operate differently with regard to the frequency and use of the patterns. The investigation focuses on four verbs in particular, pour, ta ‘take’, find and finne ‘find’, with the aim of establishing to what extent the two patterns exist side by side within the two languages, to what extent they are interchangeable in text, and to what extent they correspond to each other cross-linguistically. While the study reveals that they do exist side by side, a more complex picture emerges with regard to how interchangeable they are and to what extent they correspond to each other across the languages. As the patterns as such do not seem to have a uniform meaning, the verb becomes all the more important for the choice of the reflexive vs. the non-reflexive pattern. Cross-linguistically, although the patterns are seen to correspond to each other in some contexts, different preferences emerge for each pattern and verb in the two languages.
ER stress transcription factor Xbp1 suppresses intestinal tumorigenesis and directs intestinal stem cells
Authors: Niederreiter Lukas , Fritz Teresa M.J. , Adolph Timon E. , Krismer Anna-Maria , Offner Felix A. , Tschurtschenthaler Markus , Flak Magdalena B. , Hosomi Shuhei , Tomczak Michal F. , Kaneider Nicole C. , Sarcevic Edina , Kempster Sarah L. , Raine Tim , Esser Daniela , Rosenstiel Philip , Kohno Kenji , Iwawaki Takao , Tilg Herbert , Blumberg Richard S. , Kaser Arthur
Published: September 2013

Unresolved endoplasmic reticulum (ER) stress in the epithelium can provoke intestinal inflammation. Hypomorphic variants of ER stress response mediators, such as X-box–binding protein 1 (XBP1), confer genetic risk for inflammatory bowel disease. We report here that hypomorphic Xbp1 function instructs a multilayered regenerative response in the intestinal epithelium. This is characterized by intestinal stem cell (ISC) expansion as shown by an inositol-requiring enzyme 1α (Ire1α)–mediated increase in Lgr5+ and Olfm4+ ISCs and a Stat3-dependent increase in the proliferative output of transit-amplifying cells. These consequences of hypomorphic Xbp1 function are associated with an increased propensity to develop colitis-associated and spontaneous adenomatous polyposis coli (APC)–related tumors of the intestinal epithelium, which in the latter case is shown to be dependent on Ire1α. This study reveals an unexpected role for Xbp1 in suppressing tumor formation through restraint of a pathway that involves an Ire1α- and Stat3-mediated regenerative response of the epithelium as a consequence of ER stress. As such, Xbp1 in the intestinal epithelium not only regulates local inflammation but at the same time also determines the propensity of the epithelium to develop tumors.
p53-dependent chemokine production by senescent tumor cells supports NKG2D-dependent tumor elimination by natural killer cells
Authors: Iannello Alexandre , Thompson Thornton W. , Ardolino Michele , Lowe Scott W. , Raulet David H.
Published: September 2013

The induction of cellular senescence is an important mechanism by which p53 suppresses tumorigenesis. Using a mouse model of liver carcinoma, where cellular senescence is triggered in vivo by inducible p53 expression, we demonstrated that NK cells participate in the elimination of senescent tumors. The elimination of senescent tumor cells is dependent on NKG2D. Interestingly, p53 restoration neither increases ligand expression nor increases the sensitivity to lysis by NK cells. Instead, p53 restoration caused tumor cells to secrete various chemokines with the potential to recruit NK cells. Antibody-mediated neutralization of CCL2, but not CCL3, CCL4 or CCL5, prevented NK cell recruitment to the senescent tumors and reduced their elimination. Our findings suggest that elimination of senescent tumors by NK cells occurs as a result of the cooperation of signals associated with p53 expression or senescence, which regulate NK cell recruitment, and other signals that induce NKG2D ligand expression on tumor cells.
Intestinal monocytes and macrophages are required for T cell polarization in response to Citrobacter rodentium
Authors: Schreiber Heidi A. , Loschko Jakob , Karssemeijer Roos A. , Escolano Amelia , Meredith Matthew M. , Mucida Daniel , Guermonprez Pierre , Nussenzweig Michel C.
Published: September 2013

Dendritic cells (DCs), monocytes, and macrophages are closely related phagocytes that share many phenotypic features and, in some cases, a common developmental origin. Although the requirement for DCs in initiating adaptive immune responses is well appreciated, the role of monocytes and macrophages remains largely undefined, in part because of the lack of genetic tools enabling their specific depletion. Here, we describe a two-gene approach that requires overlapping expression of LysM and Csf1r to define and deplete monocytes and macrophages. The role of monocytes and macrophages in immunity to pathogens was tested by their selective depletion during infection with Citrobacter rodentium. Although neither cell type was required to initiate immunity, monocytes and macrophages contributed to the adaptive immune response by secreting IL-12, which induced Th1 polarization and IFN-γ secretion. Thus, whereas DCs are indispensable for priming naive CD4+ T cells, monocytes and macrophages participate in intestinal immunity by producing mediators that direct T cell polarization.
Alveolar macrophages develop from fetal monocytes that differentiate into long-lived cells in the first week of life via GM-CSF
Authors: Guilliams Martin , De Kleer Ismé , Henri Sandrine , Post Sijranke , Vanhoutte Leen , De Prijck Sofie , Deswarte Kim , Malissen Bernard , Hammad Hamida , Lambrecht Bart N.
Published: September 2013

Tissue-resident macrophages can develop from circulating adult monocytes or from primitive yolk sac–derived macrophages. The precise ontogeny of alveolar macrophages (AMFs) is unknown. By performing BrdU labeling and parabiosis experiments in adult mice, we found that circulating monocytes contributed minimally to the steady-state AMF pool. Mature AMFs were undetectable before birth and only fully colonized the alveolar space by 3 d after birth. Before birth, F4/80hiCD11blo primitive macrophages and Ly6ChiCD11bhi fetal monocytes sequentially colonized the developing lung around E12.5 and E16.5, respectively. The first signs of AMF differentiation appeared around the saccular stage of lung development (E18.5). Adoptive transfer identified fetal monocytes, and not primitive macrophages, as the main precursors of AMFs. Fetal monocytes transferred to the lung of neonatal mice acquired an AMF phenotype via defined developmental stages over the course of one week, and persisted for at least three months. Early AMF commitment from fetal monocytes was absent in GM-CSF–deficient mice, whereas short-term perinatal intrapulmonary GM-CSF therapy rescued AMF development for weeks, although the resulting AMFs displayed an immature phenotype. This demonstrates that tissue-resident macrophages can also develop from fetal monocytes that adopt a stable phenotype shortly after birth in response to instructive cytokines, and then self-maintain throughout life.
Divergent effects of α- and β-myosin heavy chain isoforms on the N terminus of rat cardiac troponin T
Authors: Mamidi Ranganath , Chandra Murali
Published: September 2013

Divergent effects of α– and β–myosin heavy chain (MHC) isoforms on contractile behavior arise mainly because of their impact on thin filament cooperativity. The N terminus of cardiac troponin T (cTnT) also modulates thin filament cooperativity. Our hypothesis is that the impact of the N terminus of cTnT on thin filament activation is modulated by a shift from α- to β-MHC isoform. We engineered two recombinant proteins by deleting residues 1–43 and 44–73 in rat cTnT (RcTnT): RcTnT1–43Δ and RcTnT44–73Δ, respectively. Dynamic and steady-state contractile parameters were measured at sarcomere length of 2.3 µm after reconstituting proteins into detergent-skinned muscle fibers from normal (α-MHC) and propylthiouracil-treated (β-MHC) rat hearts. α-MHC attenuated Ca2+-activated maximal tension (∼46%) in RcTnT1–43Δ fibers. In contrast, β-MHC decreased tension only by 19% in RcTnT1–43Δ fibers. Both α- and β-MHC did not affect tension in RcTnT44–73Δ fibers. The instantaneous muscle fiber stiffness measurements corroborated the divergent impact of α- and β-MHC on tension in RcTnT1–43Δ fibers. pCa50 (-log of [Ca2+]free required for half-maximal activation) decreased significantly by 0.13 pCa units in α-MHC + RcTnT1–43Δ fibers but remained unaltered in β-MHC + RcTnT1–43Δ fibers, demonstrating that β-MHC counteracted the attenuating effect of RcTnT1–43Δ on myofilament Ca2+ sensitivity. β-MHC did not alter the sudden stretch–mediated recruitment of new cross-bridges (ER) in RcTnT1–43Δ fibers, but α-MHC attenuated ER by 36% in RcTnT1–43Δ fibers. The divergent impact of α- and β-MHC on how the N terminus of cTnT modulates contractile dynamics has implications for heart disease; alterations in cTnT and MHC are known to occur via changes in isoform expression or mutations.
Citizen Coke: An Environmental and Political History of the Coca-Cola Company
Authors: Elmore Bartow J.
Published: September 2013

Blending business and environmental history, Citizen Coke seeks to answer a simple question: how did the Coca-Cola Company acquire the natural resources it needed to become one of the most ubiquitous branded items of commercial trade in the twentieth century? The dissertation shows how Coke satiated its ecological appetite by depending on state institutions and private sector partners that built infrastructure Coke required to extract, at low cost, raw materials for its beverage products. Not just a story of one soda company, Citizen Coke chronicles the making of Coca-Cola capitalism, a new strategy for accumulating profits first introduced in the Gilded Age that involved scavenging natural capital abundance generated by vertically integrated industrial empires, agribusinesses, and government-run utilities.
Are Calanus spp. shifting poleward in the North Atlantic? A habitat modelling approach
Authors: Chust Guillem , Castellani Claudia , Licandro Priscilla , Ibaibarriaga Leire , Sagarminaga Yolanda , Irigoien Xabier
Published: September 2013

Chust, G., Castellani, C., Licandro, P., Ibaibarriaga, L., Sagarminaga, Y., and Irigoien, X. 2014. Are Calanus spp. shifting poleward in the North Atlantic? A habitat modelling approach. – ICES Journal of Marine Science, 71: 241–253. In the last decade, the analysis based on Continuous Plankton Recorder survey in the eastern North Atlantic Ocean detected one of the most striking examples of marine poleward migration related to sea warming. The main objective of this study is to verify the poleward shift of zooplankton species (Calanus finmarchicus, C. glacialis, C. helgolandicus, C. hyperboreus) for which distributional changes have been recorded in the North Atlantic Ocean and to assess how much of this shift was triggered by sea warming, using Generalized Additive Models. To this end, the population gravity centre of observed data was compared with that of a series of simulation experiments: (i) a model using only climate factors (i.e. niche-based model) to simulate species habitat suitability, (ii) a model using only temporal and spatial terms to reconstruct the population distribution, and (iii) a model using both factors combined, using a subset of observations as independent dataset for validation. Our findings show that only C. finmarchicus had a consistent poleward shift, triggered by sea warming, estimated in 8.1 km per decade in the North Atlantic (16.5 per decade for the northeast), which is substantially lower than previous works at the assemblage level and restricted to the Northeast Atlantic. On the contrary, C. helgolandicus is expanding in all directions, although its northern distribution limit in the North Sea has shifted northward. Calanus glacialis and C. hyperboreus, which have the geographic centres of populations mainly in the NW Atlantic, showed a slight southward shift, probably responding to cool water penetrating southward in the Labrador Current. Our approach, supported by high model accuracy, shows its power in detecting species latitudinal shifts and identifying its causes, since the trend of occurrence observed data is influenced by the sampling frequency, which has progressively concentrated to lower latitudes with time.
Nutritional Therapy in Pediatric Crohn Disease
Authors: Suskind David L. , Wahbeh Ghassan , Gregory Nila , Vendettuoli Heather , Christie Dennis
Published: September 2013

Objectives:

Crohn disease is characterized by chronic intestinal inflammation in the absence of a recognized etiology. Nutritional therapy in the form of exclusive enteral nutrition (EEN) has an established role within pediatric Crohn disease. Following exclusive enteral nutrition's success, many dietary therapies focusing on the elimination of specific complex carbohydrates have been anecdotally reported to be successful.

Methods:

Many of these therapies have not been evaluated scientifically; therefore, we reviewed the medical records of our patients with Crohn disease on the specific carbohydrate diet (SCD).

Results:

Seven children with Crohn disease receiving the SCD and no immunosuppressive medications were retrospectively evaluated. Duration of the dietary therapy ranged from 5 to 30 months, with an average of 14.6 ± 10.8 months. Although the exact time of symptom resolution could not be determined through chart review, all symptoms were notably resolved at a routine clinic visit 3 months after initiating the diet. Each patient's laboratory indices, including serum albumin, C‐reactive protein, hematocrit, and stool calprotectin, either normalized or significantly, improved during follow‐up clinic visits.

Conclusions:

This chart review suggests that the SCD and other low complex carbohydrate diets may be possible therapeutic options for pediatric Crohn disease. Further prospective studies are required to fully assess the safety and efficacy of the SCD, or any other low complex SCDs in pediatric patients with Crohn disease.
A recollection of mTOR signaling in learning and memory
Authors: Graber Tyson E. , McCamphill Patrick K. , Sossin Wayne S.
Published: September 2013

Mechanistic target of rapamcyin (mTOR) is a central player in cell growth throughout the organism. However, mTOR takes on an additional, more specialized role in the developed neuron, where it regulates the protein synthesis-dependent, plastic changes underlying learning and memory. mTOR is sequestered in two multiprotein complexes (mTORC1 and mTORC2) that have different substrate specificities, thus allowing for distinct functions at synapses. We will examine how learning activates the mTOR complexes, survey the critical effectors of this pathway in the context of synaptic plasticity, and assess whether mTOR plays an instructive or permissive role in generating molecular memory traces.
The roles of protein kinases in learning and memory
Authors: Giese Karl Peter , Mizuno Keiko
Published: September 2013

In the adult mammalian brain, more than 250 protein kinases are expressed, but only a few of these kinases are currently known to enable learning and memory. Based on this information it appears that learning and memory-related kinases either impact on synaptic transmission by altering ion channel properties or ion channel density, or regulate gene expression and protein synthesis causing structural changes at existing synapses as well as synaptogenesis. Here, we review the roles of these kinases in short-term memory formation, memory consolidation, memory storage, retrieval, reconsolidation, and extinction. Specifically, we discuss the roles of calcium/calmodulin-dependent kinase II (CaMKII), the calcium/calmodulin kinase cascade, extracellular signal regulated kinase 1 and 2 (ERK1/2), cAMP-dependent protein kinase A (PKA), cGMP-dependent protein kinase G (PKG), the phosphatidylinositol 3-kinase (PI3K) pathway, and protein kinase M ζ (PKMζ). Although these kinases are important for learning and memory processes, much remains to be learned as to how they act. Therefore, it will be important to identify and characterize the critical phosphorylation substrates so that a sophisticated understanding of learning and memory processes will be achieved. This will also allow for a systematic analysis of dysfunctional kinase activity in mental disorders.
Distinct Roles of LAFL Network Genes in Promoting the Embryonic Seedling Fate in the Absence of VAL Repression
Authors: Jia Haiyan , McCarty Donald R. , Suzuki Masaharu
Published: September 2013

The transition between seed and seedling phases of development is coordinated by an interaction between the closely related ABSCISIC ACID-INSENSITIVE3 (ABI3), FUSCA3 (FUS3), and LEAFY COTYLEDON2 (LEC2; AFL) and VIVIPAROUS1/ABI3-LIKE (VAL) clades of the B3 transcription factor family that respectively activate and repress the seed maturation program. In the val1 val2 double mutant, derepression of the LEC1, LEC1-LIKE (L1L), and AFL (LAFL) network is associated with misexpression of embryonic characteristics resulting in arrested seedling development. We show that while the frequency of the embryonic fate in val1 val2 seedlings depends on the developmental timing of seed rescue, VAL proteins repress LAFL genes during germination, but not during seed development. Quantitative analysis of LAFL mutants that suppress the val1 val2 seedling phenotype revealed distinct roles of LAFL genes in promoting activation of the LAFL network. LEC2 and FUS3 are both essential for coordinate activation of the network, whereas effects of LEC1, L1L, and ABI3 are additive. Suppression of the val1 val2 seedling phenotype by the B3 domain-deficient abi3-12 mutation indicates that ABI3 activation of the LAFL network requires the B3 DNA-binding domain. In the VAL-deficient background, coordinate regulation of the LAFL network is observed over a wide range of genetic and developmental conditions. Our findings highlight distinct functional roles and interactions of LAFL network genes that are uncovered in the absence of VAL repressors.
Feedback Inhibition of Starch Degradation in Arabidopsis Leaves Mediated by Trehalose 6-Phosphate
Authors: Martins Marina Camara Mattos , Hejazi Mahdi , Fettke Joerg , Steup Martin , Feil Regina , Krause Ursula , Arrivault Stéphanie , Vosloh Daniel , Figueroa Carlos María , Ivakov Alexander , Yadav Umesh Prasad , Piques Maria , Metzner Daniela , Stitt Mark , Lunn John Edward
Published: September 2013

Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by β-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 µm in the cytosol, 0.2 to 0.5 µm in the chloroplasts, and 0.05 µm in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night.
Blind source separation and automatic tissue typing of microdiffraction data by hierarchical nonnegative matrix factorization
Authors: Ladisa Massimo , Lamura Antonio , Laudadio Teresa
Published: September 2013

In this article a nonnegative blind source separation technique, known as nonnegative matrix factorization, is applied to microdiffraction data in order to extract characteristic patterns and to determine their spatial distribution in tissue typing problems occurring in bone-tissue engineering. In contrast to other blind source separation methods, nonnegative matrix factorization only requires nonnegative constraints on the extracted sources and corresponding weights, which makes it suitable for the analysis of data occurring in a variety of applications. In particular, here nonnegative matrix factorization is hierarchically applied to two-dimensional meshes of X-ray diffraction data measured in bone samples with implanted tissue. Such data are characterized by nonnegative profiles and their analysis provides significant information about the structure of possibly new deposited bone tissue. A simulation and real data studies show that the proposed method is able to retrieve the patterns of interest and to provide a reliable and accurate segmentation of the given X-ray diffraction data.
A wide-angle X-ray fibre diffraction method for quantifying collagen orientation across large tissue areas: application to the human eyeball coat
Authors: Pijanka Jacek Klaudiusz , Abass Ahmed , Sorensen Thomas , Elsheikh Ahmed , Boote Craig
Published: September 2013

A quantitative map of collagen fibril orientation across the human eyeball coat, including both the cornea and the sclera, has been obtained using a combination of synchrotron wide-angle X-ray scattering (WAXS) and three-dimensional point mapping. A macromolecular crystallography beamline, in a custom-modified fibre diffraction setup, was used to record the 1.6 nm intermolecular equatorial reflection from fibrillar collagen at 0.5 mm spatial resolution across a flat-mounted human eyeball coat. Fibril orientation, derived as an average measure of the tissue thickness, was quantified by extraction of the azimuthal distribution of WAXS scatter intensity. Vector plots of preferential fibre orientation were remapped onto an idealized eyeball surface using a custom-built numerical algorithm, to obtain a three-dimensional representation of the collagen fibril architecture.
Rent Management – The Heart of Green Industrial Policy
Authors: Schmitz Hubert , Johnson Oliver , Altenburg Tilman
Published: September 2013

At the heart of green industrial policy is rent management: government creating and withdrawing opportunities for highly profitable investment. This paper asks what the key factors are for rent management to succeed. Drawing on a range of literatures the paper first deals with the critical success factors for ‘normal’ rent management and then turns to one of the most pressing and controversial issues of our time: how to bring about the transition to renewable energy. This is extra challenging because technological uncertainties are high, time horizons for investment are long, yet action is required now. The paper suggests that responding to these challenges requires above all a political approach to rent management. The critical success factors for managing such policy rents are those that enable it to mitigate four risks: political capture by private investors and allied policy makers; choosing the wrong instruments; targeting the wrong sectors or technologies; and doing too little. The paper concludes that a public‐private‐civic alliance is needed to deal with the most fundamental risk of governments doing too little and not achieving the scaling up of green investment.
Rotordynamic Crack Diagnosis: Distinguishing Crack Depth and Location
Authors: Varney Philip , Green Itzhak
Published: September 2013

The goal of this work is to establish simple condition monitoring principles for diagnosing the depth and location of transverse fatigue cracks in a rotordynamic system. The success of an on-line crack diagnosis regimen hinges on the accuracy of the crack model, which should account for the crack's depth and location. Two gaping crack models are presented; the first emulates a finite-width notch typically manufactured for experimental purposes, while the second models a gaping fatigue crack. The rotordynamic model used herein is based upon an available overhung rotordynamic test rig that was originally constructed to monitor the dynamics of a mechanical face seal. Four degree-of-freedom, linear equations of motion for both crack models are presented and discussed. Free and forced response analyses are presented, emphasizing results applicable to condition monitoring and, particularly, to diagnosing the crack parameters. The results demonstrate that two identifiers are required to diagnose the crack parameters: the 2X resonance shaft speed and the magnitude of the angular 2X subharmonic resonance. First, a contour plot of the 2X resonance shaft speed versus crack depth and location is generated. The magnitude of the 2X resonance along the desired 2X frequency contour is then obtained, narrowing the possible pairs of crack location and depth to either one or two possibilities. Practical aspects of the suggested diagnostic procedure are discussed, as well as qualitative observations concerning crack detection.
Turbulent Flame Speed as an Indicator for Flashback Propensity of Hydrogen-Rich Fuel Gases
Authors: Lin Yu-Chun , Daniele Salvatore , Jansohn Peter , Boulouchos Konstantinos
Published: September 2013

The turbulent flame speed (ST) is proposed to be an indicator of the flashback propensity for hydrogen-rich fuel gases at gas turbine relevant conditions. Flashback is an inevitable issue to be concerned about when introducing fuel gases containing high hydrogen content to gas turbine engines, which are conventionally fueled with natural gas. These hydrogen-containing fuel gases are present in the process of the integrated gasification combined cycle (IGCC), with and without precombustion carbon capture, and both syngas (H2 + CO) and hydrogen with various degrees of inert dilution fall in this category. Thus, a greater understanding of the flashback phenomenon for these mixtures is necessary in order to evolve the IGCC concept (either with or without carbon capture) into a promising candidate for clean power generation. Compared to syngas, the hydrogen-rich fuel mixtures exhibit an even narrower operational envelope between the occurrence of lean blow out and flashback. When flashback occurs, the flame propagation is found to occur exclusively in the boundary layer of the pipe supplying the premixed fuel/air mixture to the combustor. This finding is based on the experimental investigation of turbulent lean-premixed nonswirled confined jet flames for three fuel mixtures with H2 > 70 vol. %. Measurements were performed up to 10 bar at a fixed bulk velocity at the combustor inlet (u0 = 40 m/s) and preheat temperature (T0 = 623 K). Flame front characteristics were retrieved via planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) diagnostics and the turbulent flame speed (ST) was derived, accordingly, from the perspective of a global consumption rate. Concerning the flashback limit, the operational range of the hydrogen-rich mixtures is found to be well represented by the velocity gradients prescribed by the flame (gc) and the flow (gf), respectively. The former (gc) is determined as ST/(Le × δL0), where Le is the Lewis number and δL0 is the calculated thermal thickness of the one-dimensional laminar flame. The latter (gf) is predicted by the Blasius correlation for fully developed turbulent pipe flow and it indicates the capability with which the flow can counteract the opposed flame propagation. Our results show that the equivalence ratios at which the two velocity gradients reach similar levels correspond well to the flashback limits observed at various pressures. The methodology is also found to be capable of predicting the aforementioned difference in the operational range between syngas and hydrogen-rich mixtures.
The Role of Pivot Stiffness on the Dynamic Force Coefficients of Tilting Pad Journal Bearings
Authors: San Andrés Luis , Tao Yujiao
Published: September 2013

Recent comprehensive experimental data showcasing the force coefficients of commercial size tilting pad journal bearings has brought to rest the long standing issue on the adequacy of the [K,C,M] physical model to represent frequency independent bearing force coefficients, in particular viscous damping. Most experimental works test tilting pad journal bearings (TPJBs) with large preloads, operating over a large wide range of rotor speeds, and with null to beyond normal specific loads. Predictions from apparently simple fluid film bearing models stand poor against the test data which invariably signals to theory missing pivot and pad flexibility effects, and most importantly, ignoring significant differences in bearing and pad clearances due to actual operation, poor installation and test procedures, or simply errors in manufacturing and assembly. Presently, a conventional thermo hydrodynamic bulk flow model for prediction of the pressure and temperature fields in TPJBs is detailed. The model accounts for various pivot stiffness types, all load dependent and best when known empirically, and allows for dissimilar pad and bearing clearances. The algorithm, reliable even for very soft pad-pivots, predicts frequency reduced bearing impedance coefficients and over a certain frequency range delivers the bearing stiffness, damping and virtual mass force coefficients. Good correlation of predictions against a number of experimental results available in the literature bridges the gap between a theoretical model and the applications. Predicted pad reaction loads reveal large pivot deflections, in particular for a bearing with large preloaded pads, with significant differences in pivot stiffness as a function of specific load and operating speed. The question on how pivot stiffness acts to increase (or decrease) the bearing force coefficients, in particular the dynamic stiffness versus frequency, remains since the various experimental data show contradictory results. A predictive study with one of the test bearings varies its pivot stiffness from 10% of the fluid film stiffness to an almost rigid one, 100 times larger. With certainty, bearings with nearly rigid pivot stiffness show frequency independent force coefficients. However, for a range of pad pivot stiffness, 1/10 to ten times the fluid film stiffness, TPJB impedances vary dramatically with frequency, in particular as the excitation frequency grows above synchronous speed. The bearing virtual mass coefficients become negative, thus stiffening the bearing for most excitation frequencies.
Humidification Effects of Proton Exchange Membrane Fuel Cell With Conventional and Interdigitated Flow Field
Authors: Jian Qi-fei , Ma Guang-qing , Zhao Yang , Xiao Kai
Published: September 2013

A three-dimensional and steady-state model was developed to explore the effects of fuel gas humidification on cell performance for conventional and interdigitated flow fields in proton exchange membrane fuel cells (PEMFCs). Effects on the current density, temperature difference, and water content have been simulated and analyzed, respectively, with conventional and interdigitated flow field when the humidification in the anode or cathode is from 25% to 100%, respectively. The numerical results show that, when RHa (the anode-side relative humidity) is 100%, the current density decreases as RHc (the cathode-side relative humidity) increases with conventional flow field, but for PEMFC with interdigitated flow field, the current density increases first and then decreases as RHc increases. When RHc ranges from 50% to 75%, temperature difference on the membrane has little change. Membrane water content for PEMFC with interdigitated flow field is higher, with the maximum water content 16.67 at cell voltage of 0.4 V.
Evaluation of the robustness of the preprocessing technique improving reversible compressibility of CT images: Tested on various CT examinations
Authors: Jeon Chang Ho , Kim Kil Joong , Lee Kyoung Ho , Kim Bohyoung , Kim Tae Ki , Gu Bon Seung , Lee Jong Min
Published: September 2013

Purpose:

To modify the preprocessing technique, which was previously proposed, improving compressibility of computed tomography (CT) images to cover the diversity of three dimensional configurations of different body parts and to evaluate the robustness of the technique in terms of segmentation correctness and increase in reversible compression ratio (CR) for various CT examinations.

Methods:

This study had institutional review board approval with waiver of informed patient consent. A preprocessing technique was previously proposed to improve the compressibility of CT images by replacing pixel values outside the body region with a constant value resulting in maximizing data redundancy. Since the technique was developed aiming at only chest CT images, the authors modified the segmentation method to cover the diversity of three dimensional configurations of different body parts. The modified version was evaluated as follows. In randomly selected 368 CT examinations (352 787 images), each image was preprocessed by using the modified preprocessing technique. Radiologists visually confirmed whether the segmented region covers the body region or not. The images with and without the preprocessing were reversibly compressed using Joint Photographic Experts Group (JPEG), JPEG2000 two‐dimensional (2D), and JPEG2000 three‐dimensional (3D) compressions. The percentage increase in CR per examination (CRI) was measured.

Results:

The rate of correct segmentation was 100.0% (95% CI: 99.9%, 100.0%) for all the examinations. The median of CRI were 26.1% (95% CI: 24.9%, 27.1%), 40.2% (38.5%, 41.1%), and 34.5% (32.7%, 36.2%) in JPEG, JPEG2000 2D, and JPEG2000 3D, respectively.

Conclusions:

In various CT examinations, the modified preprocessing technique can increase in the CR by 25% or more without concerning about degradation of diagnostic information.
Light wavelength effects in submicrometer phosphor materials using Mie scattering and Monte Carlo simulation
Authors: Liaparinos P. F.
Published: September 2013

Purpose:

Phosphor materials provide challenges to both fundamental research and breakthrough development of technologies in research areas. In recent years, with the development of science and technology in the field of materials, a number of physical or chemical synthesis methods have been developed and successfully used for the preparation of submicrometer‐sized phosphors. The present paper provides a rigorous analysis of light diffusion capabilities of phosphor materials in submicrometer‐scale investigating the effect of light wavelength.

Methods:

Mie scattering theory and Monte Carlo simulation techniques were used for the optical diffusion performance providing numerical calculations. The Monte Carlo model included: (i) phosphor layers composed of different thickness (200, 500, 1000μm) and (ii) different light wavelength values (420, 545, 610 nm) corresponding to different types of activators, such as Ce, Tb, and Eu activators, respectively.

Results:

Based on Mie calculations, it was found that for low values of refractive index (e.g., 1.4) and for particle radius from 250 up to 500 nm no significant variations occurred on optical parameters. Monte Carlo simulations showed that the resolution increases as light wavelength decreases, respectively, however, this increase is more obvious at lower thickness values (i.e., at 200μm). In particular, as light wavelength decreases from 610 down to 545 and 420 nm, the resolution increases 4.4% and 13.9%, respectively (at 200 μm layer thickness). In addition, as layer thickness increases from 200 up to 500 μm the resolution decreases 50.2% while an increase up to 1000 μm causes a decrease of 70.2% (at 420 nm light wavelength).

Conclusions:

The goal of the authorˈs study was to investigate the optical diffusion characteristics of submicrometer phosphor materials using Mie scattering theory and Monte Carlo simulation. The present investigation indicated that a key parameter on resolution improvement was the amount of light loss which depends on the choice of activator and affects the lateral spreading.
Is There a Maximum Size of Water Drops in Nature?
Authors: Vollmer Michael , Möllmann Klaus-Peter
Published: September 2013

In nature, waterdrops can have a large variety of sizes and shapes. Small droplets with diameters of the order of 5 to 10 μm are present in fog and clouds. This is not sufficiently large for gravity to dominate their behavior. In contrast, raindrops typically have sizes of the order of 1 mm, with observed maximum sizes in nature of around 5 mm in tropical rain showers. Electric fields in the atmosphere lead to the largest sizes.1 Raindrops in natural rain showers cannot reach arbitrarily large sizes. Which factors govern the maximum size of water drops?
Quadrant to Measure the Sun's Altitude
Authors: Morgan Windsor A.
Published: September 2013

The changing altitude of the Sun (either over the course of a day or longer periods) is a phenomenon that students do not normally appreciate.1 However, the altitude of the Sun affects many topics in disciplines as diverse as astronomy, meteorology, navigation, or horology, such as the basis for seasons, determination of latitude and longitude, or the determination of local apparent noon. Being familiar with the motion of the Sun is important for students' understanding of these different subjects. To be able to concretely understand the Sun's altitude, a hands-on approach is necessary, because actually making observations will stay with a student much longer than reading or hearing about it.
Move Over, TLR4
Authors: Mueller Kristen L.
Published: September 2013

Cytoplasmic lipopolysaccharide from Gram-negative bacteria can activate the innate immune system directly.
Effects of Body Size and Gender on the Population Pharmacokinetics of Artesunate and Its Active Metabolite Dihydroartemisinin in Pediatric Malaria Patients
Authors: Morris Carrie A. , Tan Beesan , Duparc Stephan , Borghini-Fuhrer Isabelle , Jung Donald , Shin Chang-Sik , Fleckenstein Lawrence
Published: September 2013

Despite the important role of the antimalarial artesunate and its active metabolite dihydroartemisinin (DHA) in malaria treatment efforts, there are limited data on the pharmacokinetics of these agents in pediatric patients. This study evaluated the effects of body size and gender on the pharmacokinetics of artesunate-DHA using data from pediatric and adult malaria patients. Nonlinear mixed-effects modeling was used to obtain a base model consisting of first-order artesunate absorption and one-compartment models for artesunate and for DHA. Various methods of incorporating effects of body size descriptors on clearance and volume parameters were tested. An allometric scaling model for weight and a linear body surface area (BSA) model were deemed optimal. The apparent clearance and volume of distribution of DHA obtained with the allometric scaling model, normalized to a 38-kg patient, were 63.5 liters/h and 65.1 liters, respectively. Estimates for the linear BSA model were similar. The 95% confidence intervals for the estimated gender effects on clearance and volume parameters for artesunate fell outside the predefined no-relevant-clinical-effect interval of 0.75 to 1.25. However, the effect of gender on apparent DHA clearance was almost entirely contained within this interval, suggesting a lack of an influence of gender on this parameter. Overall, the pharmacokinetics of artesunate and DHA following oral artesunate administration can be described for pediatric patients using either an allometric scaling or linear BSA model. Both models predict that, for a given artesunate dose in mg/kg of body weight, younger children are expected to have lower DHA exposure than older children or adults.
Tissue Pharmacokinetics of Cefazolin in Patients with Lower Limb Infections
Authors: Bhalodi Amira A. , Housman Seth T. , Shepard Ashley , Nugent James , Nicolau David P.
Published: September 2013

Cefazolin, a first-generation cephalosporin with activity against methicillin-susceptible
Staphylococcus aureus
and streptococci, is often used to treat lower limb infections caused by these pathogens. Antimicrobial penetration is often limited in these patients due to compromised vasculature. Therefore, we sought to evaluate the exposure profile of cefazolin in serum and tissue in patients with lower limb infections. An
in vivo
microdialysis catheter was inserted into the tissue near the margin of the wound and constantly perfused with lactated Ringer's solution. Steady-state serum and tissue samples were simultaneously collected over a dosing interval. Serum protein binding was also assessed. Serum concentrations were analyzed by noncompartmental analysis. Tissue concentrations were corrected for percent
in vivo
recovery by using the retrodialysis technique. Seven patients with a mean weight of 95.45 ± 18.51 kg and a mean age of 54 ± 19 years were enrolled. Six patients received 1 g every 8 h, and one patient received 2 g every 24 h due to acute kidney injury. The free area under the curve from 0 to 8 h (
f
AUC
0–8
) values for serum and wound were 48.0 ± 18.66 and 56.35 ± 41.17 μg · h/ml, respectively, for the patients receiving 1 g every 8 h. The
f
AUC
0–24
values for serum and wound were 1,326.1 and 253.9 μg · h/ml, respectively, for the single patient receiving 2 g every 24 h. The mean tissue penetration ratio (tissue/serum
f
AUC ratio) was 1.06. These data suggest that the amount of time that free-drug concentrations remain above the MIC (
fT
>MIC) for cefazolin in wound tissue is adequate to treat patients with lower limb infections.
National Prevalence of Resistance to Third-Generation Cephalosporins in Escherichia coli Isolates from Layer Flocks in France
Authors: Chauvin Claire , Le Devendec Laetitia , Jouy Eric , Le Cornec Maena , Francart Sylvie , Marois-Créhan Corinne , Kempf Isabelle
Published: September 2013

Resistance of
Escherichia coli
to third-generation cephalosporin (3GC) in fecal samples representative of French egg production was studied. The susceptibility to cefotaxime of
E. coli
isolates obtained by culture on nonselective media was determined. Twenty-two nonsusceptible isolates were obtained (7.51%; 95% confidence interval, 4.49 to 10.54%), the majority of which came from young birds. Most isolates carried a
bla
CTX-M-1
group gene, and a few carried a
bla
CMY-2
-like gene. Control of 3GC resistance in laying hens is needed.
In Vitro
Cross-Linking of Mycobacterium tuberculosis Peptidoglycan by
l
,
d
-Transpeptidases and Inactivation of These Enzymes by Carbapenems
Authors: Cordillot Mathilde , Dubée Vincent , Triboulet Sébastien , Dubost Lionel , Marie Arul , Hugonnet Jean-Emmanuel , Arthur Michel , Mainardi Jean-Luc
Published: September 2013

The
Mycobacterium tuberculosis
peptidoglycan is cross-linked mainly by
l
,
d
-transpeptidases (LDTs), which are efficiently inactivated by a single β-lactam class, the carbapenems. Development of carbapenems for tuberculosis treatment has recently raised considerable interest since these drugs, in association with the β-lactamase inhibitor clavulanic acid, are uniformly active against extensively drug-resistant
M. tuberculosis
and kill both exponentially growing and dormant forms of the bacilli. We have purified the five
l
,
d
-transpeptidase paralogues of
M. tuberculosis
(Mt1 to -5) and compared their activities with those of peptidoglycan fragments and carbapenems. The five LDTs were functional
in vitro
since they were active in assays of peptidoglycan cross-linking (Mt5), β-lactam acylation (Mt3), or both (Mt1, Mt2, and Mt4). Mt3 was the only LDT that was inactive in the cross-linking assay, suggesting that this enzyme might be involved in other cellular functions such as the anchoring of proteins to peptidoglycan, as shown in
Escherichia coli
. Inactivation of LDTs by carbapenems is a two-step reaction comprising reversible formation of a tetrahedral intermediate, the oxyanion, followed by irreversible rupture of the β-lactam ring that leads to formation of a stable acyl enzyme. Determination of the rate constants for these two steps revealed important differences (up to 460-fold) between carbapenems, which affected the velocity of oxyanion and acyl enzyme formation. Imipenem inactivated LDTs more rapidly than ertapenem, and both drugs were more efficient than meropenem and doripenem, indicating that modification of the carbapenem side chain could be used to optimize their antimycobacterial activity.
Comparison of Cytokine Immune Responses to Brucella abortus and Yersinia enterocolitica Serotype O:9 Infections in BALB/c Mice
Authors: Gu Wenpeng , Wang Xin , Qiu Haiyan , Cui Buyun , Zhao Shiwen , Zheng Han , Xiao Yuchun , Liang Junrong , Duan Ran , Jing Huaiqi
Published: September 2013

Brucella abortusandYersinia enterocoliticaserotype O:9 serologically cross-react in the immune response with the host; therefore, our aim was to compare the immune responses to these two pathogens. We selected typicalB. abortusandY. enterocoliticaO:9 strains to study the cytokine immune response and the histopathological changes in livers and spleens of BALB/c mice. The data showed the cytokine responses to the two strains of pathogens were different, where the average levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), gamma interferon (IFN-γ), interleukin-12 (IL-12), and tumor necrosis factor alpha (TNF-α) were higher withB. abortusinfections than withY. enterocoliticaO:9 infections, especially for IFN-γ, while the IL-10 level was lower and the levels of IL-1β, IL-4, IL-5, and IL-6 were similar. The histopathological effects in the livers and spleens of the BALB/c mice withB. abortusandY. enterocoliticaO:9 infections were similar; however, the pathological changes in the liver were greater withB. abortusinfections, while damage in the spleen was greater withY. enterocoliticaO:9 infections. These observations show that different cytokine responses and histopathological changes occur withB. abortusandY. enterocoliticaO:9 infections.
Interleukin-10 (IL-10) Inhibits Borrelia burgdorferi-Induced IL-17 Production and Attenuates IL-17-Mediated Lyme Arthritis
Authors: Hansen Emily S. , Medić Velinka , Kuo Joseph , Warner Thomas F. , Schell Ronald F. , Nardelli Dean T.
Published: September 2013

Previous studies have shown that cells and cytokines associated with interleukin-17 (IL-17)-driven inflammation are involved in the arthritic response toBorrelia burgdorferiinfection. Here, we report that IL-17 is a contributing factor in the development of Lyme arthritis and show that its production and histopathological effects are regulated by interleukin-10 (IL-10). Spleen cells obtained fromB. burgdorferi-infected, “arthritis-resistant” wild-type C57BL/6 mice produced low levels of IL-17 following stimulation with the spirochete. In contrast, spleen cells obtained from infected, IL-10-deficient C57BL/6 mice produced a significant amount of IL-17 following stimulation withB. burgdorferi. These mice developed significant arthritis, including erosion of the bones in the ankle joints. We further show that treatment with antibody to IL-17 partially inhibited the significant hind paw swelling and histopathological changes observed inB. burgdorferi-infected, IL-10-deficient mice. Taken together, these findings provide additional evidence of a role for IL-17 in Lyme arthritis and reveal an additional regulatory target of IL-10 following borrelial infection.