bluuebunny/crossref_metadata_2025 huggingface dataset:
Spin dynamics in the modulation frame: Application to homonuclear recoupling in magic angle spinning solid-state NMR
Authors: De Paëpe Gaël , Lewandowski Józef R. , Griffin Robert G.
Published: March 2008

We introduce a family of solid-state NMR pulse sequences that generalizes the concept of second averaging in the modulation frame and therefore provides a new approach to perform magic angle spinning dipolar recoupling experiments. Here, we focus on two particular recoupling mechanisms—cosine modulated rotary resonance (CMpRR) and cosine modulated recoupling with isotropic chemical shift reintroduction (COMICS). The first technique, CMpRR, is based on a cosine modulation of the rf phase and yields broadband double-quantum (DQ) C13 recoupling using >70kHz ω1,C∕2π rf field for the spinning frequency ωr∕2=10–30kHz and H1 Larmor frequency ω0,H∕2π up to 900MHz. Importantly, for p⩾5, CMpRR recouples efficiently in the absence of H1 decoupling. Extension to lower p values (3.5⩽p<5) and higher spinning frequencies is possible using low power H1 irradiation (<0.25ωr∕2π). This phenomenon is explained through higher order cross terms including a homonuclear third spin assisted recoupling mechanism among protons. CMpRR mitigates the heating effects of simultaneous high power C13 recoupling and H1 decoupling. The second technique, COMICS, involves low power C13 irradiation that induces simultaneous recoupling of the C13 DQ dipolar and isotropic chemical shift terms. In contrast to CMpRR, where the DQ bandwidth (∼30kHz at ω0,H∕2π=750MHz) covers the entire C13 spectral width, COMICS recoupling, through the reintroduction of the isotropic chemical shift, is selective with respect to the carrier frequency, having a typical bandwidth of ∼100Hz. This approach is intended as a general frequency selective method circumventing dipolar truncation (supplementary to R2 experiments). These new γ-encoded sequences with attenuated rf requirements extend the applicability of homonuclear recoupling techniques to new regimes—high spinning and Larmor frequencies—and therefore should be of major interest for high resolution biomolecular studies.
Mixtures of interacting particles with well-defined composition field coupling χ parameters
Authors: Titievsky Kirill , Rutledge Gregory C.
Published: March 2008

This article proposes a systematic, quantitative treatment of the problem of associating a scalar Flory–Huggins-like χ parameter directly with the interaction potentials in a binary mixture of point particles. This work fulfills the need for a general, quantitative way to compare χ values in explicitly simulated ensembles of lattice and off-lattice polymer models with field theoretic calculations. Emphasis is placed on constructing particle models where χ is relatively well defined. In general, χ is defined through pair correlation functions, whose thermal fluctuations are coupled to local average composition and composition gradients. This implies that χ is composition dependent even in the simplest particle models. At the same time, by quantifying this effect, it is found that composition-independent χ may be defined to within a few percent for cases where the range of the potential is large relative to the interparticle distance. An explicit formula for χ in terms of interaction potentials is given.
Impact of mechanical stress on gate tunneling currents of germanium and silicon p-type metal-oxide-semiconductor field-effect transistors and metal gate work function
Authors: Choi Youn Sung , Numata Toshinori , Nishida Toshikazu , Harris Rusty , Thompson Scott E.
Published: March 2008

Uniaxial four-point wafer bending stress-altered gate tunneling currents are measured for germanium (Ge)/silicon (Si) channel metal-oxide-semiconductor field-effect transistors (MOSFETs) with HfO2/SiO2 gate dielectrics and TiN/P+ poly Si electrodes. Carrier separation is used to measure electron and hole currents. The strain-altered hole tunneling current from the p-type inversion layer of Ge is measured to be ∼4 times larger than that for the Si channel MOSFET, since the larger strain-induced valence band-edge splitting in Ge results in more hole repopulation into a subband with a smaller out-of-plane effective mass and a lower tunneling barrier height. The strain-altered electron tunneling current from the metal gate is measured and shown to change due to strain altering the metal work function as quantified by flatband voltage shift measurements of Si MOS capacitors with TaN electrodes.
The quenching of isopropyl group rotation in van der Waals molecular solids
Authors: Wang Xianlong , Rheingold Arnold L. , DiPasquale Antonio G. , Mallory Frank B. , Mallory Clelia W. , Beckmann Peter A.
Published: March 2008

X-ray diffraction experiments are employed to determine the molecular and crystal structure of 3-isopropylchrysene. Based on this structure, electronic structure calculations are employed to calculate methyl group and isopropyl group rotational barriers in a central molecule of a ten-molecule cluster. The two slightly inequivalent methyl group barriers are found to be 12 and 15kJmol−1 and the isopropyl group barrier is found to be about 240kJmol−1, meaning that isopropyl group rotation is completely quenched in the solid state. For comparison, electronic structure calculations are also performed in the isolated molecule, determining both the structure and the rotational barriers, which are determined to be 15kJmol−1 for both the isopropyl group and the two equivalent methyl groups. These calculations are compared with, and are consistent with, previously published NMR H1 spin-lattice relaxation experiments where it was found that the barrier for methyl group rotation was 11±1kJmol−1 and that the barrier for isopropyl group rotation was infinite on the solid state NMR time scale.
On the regularized fermionic projector of the vacuum
Authors: Finster Felix
Published: March 2008

We construct families of fermionic projectors with spherically symmetric regularization, which satisfy the condition of a distributional MP-product. The method is to analyze regularization tails with a power law or logarithmic scaling in composite expressions in the fermionic projector. The resulting regularizations break the Lorentz symmetry and give rise to a multilayer structure of the fermionic projector near the light cone. Furthermore, we construct regularizations which go beyond the distributional MP-product in that they yield additional distributional contributions supported at the origin. The remaining freedom for the regularization parameters and the consequences for the normalization of the fermionic states are discussed.
Conduction mechanisms in partially crystallized (La,Na)MnO3 films
Authors: Tovstolytkin A. I. , Gor’kov D. V. , Matvienko A. I.
Published: March 2008

The electric and magnetoresistive properties of partially crystallized (La,Na)MnO3 films near the paramagnet-ferromagnet transition are investigated. The objects of study are films obtained on polychore substrates by magnetotron sputtering and substrate temperatures 300 and 500°C. The temperature behavior of the electric resistance is analyzed to determine the limits of between the experimental data and the existing theoretical models. A generalized picture of the evolution of conduction mechanisms accompanying a change in temperature and regimes of heat treatment of the samples is constructed. It is shown that a correlation exists between the character of the temperature variation of the magnetoresistance and the change in the conduction mechanisms. The characteristic temperatures which describe the boundaries of the regions in which a definite conduction mechanism dominates are established.
Equations of motion and velocities of longitudinal waves for superfluid He-A3 filled aerogel in the presence of finite magnetic field
Authors: Kekutia Sh. E. , Chkhaidze N. D.
Published: March 2008

The dynamical equations for superfluid He–A3 filled aerogel in finite magnetic fields are determined. The speeds of propagating longitudinal modes in the A1 and A phases of this system are found. It is shown that sound phenomena in the case of He–A13 superfluid are modified from those for HeII superfluid.
Thermal conductivity of a quantum spin-1/2 antiferromagnetic chain with magnetic impurities
Authors: Zvyagin A. A.
Published: March 2008

We present an exact theory that describes how magnetic impurities change the behavior of the thermal conductivity for the integrable Heisenberg antiferromagnetic quantum spin-1/2 chain. Single magnetic impurities and a large concentration of impurities with similar values of the couplings to the host chain (a weak disorder) do not change the linear-in-temperature low-T behavior of the thermal conductivity: Only the slope of that behavior becomes smaller, compared to the homogeneous case. The strong disorder in the distribution of the impurity-host couplings produces more rapid temperature growth of the thermal conductivity, compared to the linear-in-T dependence of the homogeneous chain and the chain with weak disorder. Recent experiments on the thermal conductivity in inhomogeneous quasi-one-dimensional quantum spin systems manifest qualitative agreement with our results.
On the generalized equipartition theorem in molecular dynamics ensembles and the microcanonical thermodynamics of small systems
Authors: Uline Mark J. , Siderius Daniel W. , Corti David S.
Published: March 2008

We consider various ensemble averages within the molecular dynamics (MD) ensemble, corresponding to those states sampled during a MD simulation in which the application of periodic boundary conditions imposes a constraint on the momentum of the center of mass. As noted by Shirts et al. [J. Chem. Phys. 125, 164102 (2006)] for an isolated system, we find that the principle of equipartition is not satisfied within such simulations, i.e., the total kinetic energy of the system is not shared equally among all the translational degrees of freedom. Nevertheless, we derive two different versions of Tolman’s generalized equipartition theorem, one appropriate for the canonical ensemble and the other relevant to the microcanonical ensemble. In both cases, the breakdown of the principle of equipartition immediately follows from Tolman’s result. The translational degrees of freedom are, however, still equivalent, being coupled to the same bulk property in an identical manner. We also show that the temperature of an isolated system is not directly proportional to the average of the total kinetic energy (in contrast to the direct proportionality that arises between the temperature of the external bath and the kinetic energy within the canonical ensemble). Consequently, the system temperature does not appear within Tolman’s generalized equipartition theorem for the microcanonical ensemble (unlike the immediate appearance of the temperature of the external bath within the canonical ensemble). Both of these results serve to highlight the flaws in the argument put forth by Hertz [Ann. Phys. 33, 225 (1910); 33, 537 (1910)] for defining the entropy of an isolated system via the integral of the phase space volume. Only the Boltzmann–Planck entropy definition, which connects entropy to the integral of the phase space density, leads to the correct description of the properties of a finite, isolated system. We demonstrate that the use of the integral of the phase space volume leads to unphysical results, indicating that the property of adiabatic invariance has little to do with the behavior of small systems.
Exciton harvesting, charge transfer, and charge-carrier transport in amorphous-silicon nanopillar/polymer hybrid solar cells
Authors: Gowrishankar Vignesh , Scully Shawn R. , Chan Albert T. , McGehee Michael D. , Wang Qi , Branz Howard M.
Published: March 2008

We report on the device physics of nanostructured amorphous-silicon (a-Si:H)/polymer hybrid solar cells. Using two different polymers, poly(3-hexylthiophene) (P3HT) and poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV), we study the exciton diffusion, charge transfer, and charge-carrier transport in bilayer and nanostructured a-Si:H/polymer systems. We find that strong energy transfer occurs in the a-Si:H/MEH-PPV system. However, inefficient hole transfer from the a-Si:H to the polymers renders negligible photocurrent contribution from the a-Si:H as well as very small currents in the a-Si:H/MEH-PPV devices. These results suggest that a-Si:H may be unsuitable for use in polymer-based hybrid cells. Nanosphere lithography and reactive ion etching were used to fabricate nanopillars in a-Si:H. The nanostructured a-Si:H/P3HT devices showed improved efficiency and almost perfect charge-carrier extraction under short-circuit conditions. By modeling these nanostructured devices, the loss mechanisms were identified and solutions for higher efficiencies are suggested.
Frequency tunable electromagnetic metamaterial using ferroelectric loaded split rings
Authors: Hand Thomas H. , Cummer Steven A.
Published: March 2008

Measurements of a frequency tunable magnetic metamaterial using metallic split rings loaded with barium strontium titanate thin film capacitors are presented. The resonant frequency of this medium is voltage tunable across a 140MHz band centered at 1.75GHz. S-parameter measurements in a microstrip waveguide reveal that the effective relative permeability of the slab has a roughly Lorentzian shape that reaches minimum values between −2 and −3 for biases from 0to5V. The permeability of the slab can tune between positive and negative values, making it useful in applications requiring a state switchable magnetic permeability.
Broadband quantum dot micro-light-emitting diodes with parabolic sidewalls
Authors: Tanriseven Selim , Maaskant Pleun , Corbett Brian
Published: March 2008

Arrays of long wavelength, self-organized InGaAs quantum dot micron sized light-emitting diodes (μ-LEDs) with parabolic sidewalls are introduced. The parabolic profiles of the μ-LEDs produced by resist reflow and controlled dry etching improve the extraction efficiency from the LEDs by redirection of the light into the escape cone by reflection from the sidewalls. A fourfold increase in the substrate emitted power density compared to a reference planar LED is measured. The reflected light is verified to be azimuthally polarized. The spectral width of the emission can be greater than 200nm.
Combined electrophoretic and electro-osmotic transport through channels of periodically varying cross section
Authors: Dorfman Kevin D.
Published: March 2008

The results derived by Yariv and Dorfman [Phys. Fluids 19, 037101 (2007).] for the electrophoretic transport of a point-size Brownian particle in a narrow channel of periodically varying cross section are generalized to joint electrophoretic and electro-osmotic flow (or purely electro-osmotic flow, in the case of a neutral particle) in a channel possessing a uniform zeta potential by a suitable change in the definition of the Péclet number.
Short wavelength (4μm) quantum cascade detector based on strain compensated InGaAs∕InAlAs
Authors: Giorgetta F. R. , Baumann E. , Théron R. , Pellaton M. L. , Hofstetter D. , Fischer M. , Faist J.
Published: March 2008

We report on a quantum cascade detector based on nearly strain compensated InGaAs∕InAlAs pseudomorphically grown on InP substrate and detecting light at short wavelengths around 4μm. The background limited infrared performance (BLIP) condition is met at a temperature of 108K with a high detectivity of DBLIP*=1.2×1011Jones.
An endosomally localized isoform of Eps15 interacts with Hrs to mediate degradation of epidermal growth factor receptor
Authors: Roxrud Ingrid , Raiborg Camilla , Pedersen Nina Marie , Stang Espen , Stenmark Harald
Published: March 2008

Down-regulation of activated and ubiquitinated growth factor (GF) receptors by endocytosis and subsequent lysosomal degradation ensures attenuation of GF signaling. The ubiquitin-binding adaptor protein Eps15 (epidermal growth factor receptor [EGFR] pathway substrate 15) functions in endocytosis of such receptors. Here, we identify an Eps15 isoform, Eps15b, and demonstrate its expression in human cells and conservation across vertebrate species. Although both Eps15 and Eps15b interact with the endosomal sorting protein Hrs (hepatocyte growth factor–regulated tyrosine kinase substrate) in vitro, we find that Hrs specifically binds Eps15b in vivo (whereas adaptor protein 2 preferentially interacts with Eps15). Although Eps15 mainly localizes to clathrin-coated pits at the plasma membrane, Eps15b localizes to Hrs-positive microdomains on endosomes. Eps15b overexpression, similarly to Hrs overexpression, inhibits ligand-mediated degradation of EGFR, whereas Eps15 is without effect. Similarly, depletion of Eps15b but not Eps15 delays degradation and promotes recycling of EGFR. These results indicate that Eps15b is an endosomally localized isoform of Eps15 that is present in the Hrs complex via direct Hrs interaction and important for the sorting function of this complex.
Multiple pathways for regulation of σS (RpoS) stability in Escherichia coli via the action of multiple anti‐adaptors
Authors: Bougdour Alexandre , Cunning Christofer , Baptiste Patrick Jean , Elliott Thomas , Gottesman Susan
Published: March 2008

σS, the stationary phase sigma factor of Escherichia coli and Salmonella, is regulated at multiple levels. The σS protein is unstable during exponential growth and is stabilized during stationary phase and after various stress treatments. Degradation requires both the ClpXP protease and the adaptor RssB. The small antiadaptor protein IraP is made in response to phosphate starvation and interacts with RssB, causing σS stabilization under this stress condition. IraP is essential for σS stabilization in some but not all starvation conditions, suggesting the existence of other anti‐adaptor proteins. We report here the identification of new regulators of σS stability, important under other stress conditions. IraM (inhibitor of RssB activity during Magnesium starvation) and IraD (inhibitor of RssB activity after DNA damage) inhibit σS proteolysis both in vivo and in vitro. Our results reveal that multiple anti‐adaptor proteins allow the regulation of σS stability through the regulation of RssB activity under a variety of stress conditions.
Counteracting effect of papaverine on morphine inhibition of gastrointestinal transit in mice
Authors: Tucci P. , Palmery M. , Piccolotti P. , Pimpinella G. , Valeri P. , Romanelli L.
Published: March 2008

Abstract Oral papaverine has been shown to be capable of antagonizing the constipation induced by a single dose of oral morphine. The primary aim of the present study was to ascertain whether papaverine is also capable of counteracting morphine‐induced decrease of upper gastrointestinal transit (UGT) after repeated parenteral administration of the opioid. We next investigated the mechanisms(s) responsible for the counteracting effect of papaverine, by analysing whether this effect was changed by pretreatment withNG‐nitro‐l‐arginine methyl ester (l‐NAME), dexamethasone, indomethacin or capsaicin. Papaverine, co‐administered with morphine, counteracted the morphine‐induced decrease in UGT in mice pretreated with morphine for 3 days but did not do so in naive animals. The counteracting effect of papaverine was antagonized byl‐NAME, but not by indomethacin. In mice pretreated with both morphine and dexamethasone, papaverine failed to antagonize the effect of morphine. Capsaicin pretreatment completely abolished the effect of a single dose of morphine, the effect being partially restored by the 3 days pretreatment with morphine. In mice pretreated with both capsaicin and morphine, the UGT decrease elicited by morphine was lower than in the other experimental groups and was not modified by papaverine. Our results show that papaverine can counteract the morphine inhibition of UGT in mice repeatedly exposed to the opioid. Papaverine exerts its action through a nitric oxide synthase‐mediated mechanism; this mechanism is only effective after repeated morphine administration and does not operate when capsaicin‐sensitive afferent neurones are ablated.
Strategies to prevent spread of Leptosphaeria maculans (phoma stem canker) onto oilseed rape crops in China; costs and benefits
Authors: Fitt B. D. L. , Hu B. C. , Li Z. Q. , Liu S. Y. , Lange R. M. , Kharbanda P. D. , Butterworth M. H. , White R. P.
Published: March 2008

Field experiments in Europe have shown that Chinese cultivars of winter oilseed rape (Brassica napus) are very susceptible to the pathogen Leptosphaeria maculans (cause of phoma stem canker). Climatic and agronomic conditions in China are suitable for L. maculans since the closely related but less damaging pathogen L. biglobosa occurs on the winter and spring oilseed rape crops there. Major gene resistance to L. maculans is not durable; when introduced into commercial oilseed rape cultivars it is rapidly rendered ineffective by changes in the pathogen population. The threat to Chinese oilseed rape production from L. maculans is illustrated by the way in which L. maculans has spread into other areas of the world where previously only L. biglobosa was present, such as Canada and Poland. Models were developed to describe the spread (in space and time) of L. maculans across Alberta province, Canada, based on survey data collected over a 15‐year period. These models were used to estimate the potential spread of L. maculans across the Yangtze river oilseed rape growing areas of China and its associated costs. Short‐term strategies to prevent occurrence of severe phoma stem canker epidemics in China include training of extension workers to recognise symptoms of the disease and use of PCR‐based diagnostics to detect the pathogen on imported seed. Long‐term strategies include the introduction of durable resistance to L. maculans into Chinese oilseed rape cultivars as a component of an integrated disease management programme. The costs of such strategies in relation to costs of a phoma stem canker epidemic are discussed.
A giant catastrophic mud‐and‐debris flow in the Miocene Makran
Authors: Burg Jean‐Pierre , Bernoulli Daniel , Smit Jeroen , Dolati Ashgar , Bahroudi Abbas
Published: March 2008

We challenge the former interpretation of the ‘sedimentary mélange’ of the Makran accretionary complex as a tectonic mélange diapirically emplaced from below and provide evidence for its sedimentary gravitational emplacement from the north during Tortonian–Messinian times (between 11.8 and 5.8 Ma). It is an olistostrome that includes blocks of ophiolites and oceanic sediments derived from the ‘coloured mélange’ to the north, and reworked chunks of the turbidites on which it rests with an erosional truncation. The chaotic scattering of blocks of any size and lithology and the weak, soft‐sediment deformation of the matrix argue against a tectonic emplacement of the chaotic formation. Its size and internal structure, together with the size of the individual blocks, make the olistostrome a fossil equivalent of the large, gravitationally emplaced debris flows observed along present‐day continental margins and unstable volcanic edifices.
Hormone Profiles of Mares Affected by the Mare Reproductive Loss Syndrome
Authors: Volkmann D , Zent W , Little T , Riddle T , Durenbereger J , Potenza K , Sibley L , Roser J
Published: March 2008

Contents

While searching for the cause of the Mare Reproductive Loss syndrome (MRLS), we postulated that 1 of 3 tissues in 40–120 D pregnant mares was the likely primary target of the noxious factor that caused early abortions: The corpora lutea (CL), the endometrium or the fetus and/or its membranes. At this stage of gestation, progesterone (P4) is solely produced by luteal tissue, eCG by endometrial cups in the endometrium and oestrogens by the feto‐placental unit. We determined whether concentrations of P4, eCG and/or total conjugated oestrogens (CE) would indicate which tissue was targeted during the MRLS. P4, eCG and CE were measured in single serum samples collected from 216 mares, 60–110 D after ovulation during the 2001 MRLS outbreak. All mares had previously been confirmed pregnant by ultrasonography. The following data was obtained from each mare: Interval from ovulation, pregnancy status and normalcy of fetal fluids at the time of sampling, and pregnancy status 3 weeks after sampling and at term. There were no meaningful differences in hormone concentrations between pregnant mares that had normal and excessively echogenic fetal fluids at the time of sampling. CE were lower (p < 0.05) in mares that aborted after sample collection than in mares the carried to term. In 8 mares from which multiple samples were obtained, CE consistently decreased prior to any decreases in P4 or eCG. Arguments are presented that lead to the hypothesis that the fetal trophoblast was the primary target of the MRLS agent.
STRATEGY TO REDUCE THE RISK OF POSITIVE PANCREATIC RESECTION MARGIN AT PANCREATICO‐DUODENECTOMY
Authors: Al‐Ghnaniem Reyad , Camprodon Ricardo A. M. , Kocher Hemant M. , Portmann Bernard , Al‐Nawab Mashal , Shaikh Hizbullah , Sohail Mohammad , Patel Ameet G.
Published: March 2008

Background:  The accuracy of histological assessment of frozen section (FS) of the pancreatic resection margin (PRM) at pancreatico‐duodenectomy can be improved by concurrent FS examination of a sample of the suspected pancreatic lesion.

Methods:  A prospective trial was conducted using archived material. FS of all the PRM and suspected pancreatic lesion of 12 patients randomly selected from a historical group who underwent pancreatico‐duodenectomy for suspected malignancy were examined by five histopathologists. They were asked to examine the PRM alone and alongside the suspected lesion. The diagnosis of the PRM was ‘benign’, ‘malignant’ or ‘defer to paraffin section’. All the histopathologists were blinded to the paraffin section diagnosis.

Results:  The main outcome measures were sensitivity, specificity and the incidence of deferring to paraffin section. In this respect examination of the PRM alone had a sensitivity of 70% and a specificity of 87.5%. Concurrent FS examination of PRM with the pancreatic lesion increased the sensitivity to 90% and the specificity to 92.5%. The incidence of deferring to paraffin section was reduced from 17 to 7% (P = 0.03).

Conclusion:  This policy is recommended because it improves the diagnostic accuracy of FS evaluation of the PRM resulting in a reduction of residual pancreatic cancer at the pancreatic transection line.
PANCREATODUODENECTOMY: ROLE OF DRAIN FLUID ANALYSIS IN THE MANAGEMENT OF PANCREATIC FISTULA
Authors: Kong Justin , Gananadha Sivakumar , Hugh Thomas J. , Samra Jaswinder S.
Published: March 2008

Background:  Pancreatic fistula remains an important cause of death following pancreatoduodenectomy. There is still uncertainty regarding the use of drains following pancreatoduodenectomy with recent reports suggesting that it might be harmful with increased complications. We evaluated the use of drain fluid analysis in the management of patients following pancreatoduodenectomy.

Methods:  A prospective study was conducted on all patients undergoing pancreatoduodenectomy at two hospitals between April 2004 and August 2006. Drain fluid analysis was carried out from day 3 to day 5. These data were collected with the clinical pictures of the patients and with subsequent radiological assessment.

Results:  Fifty consecutive patients underwent modified extended pancreatoduodenectomy for a periampullary tumour. In patients with no clinical evidence of a fistula, the mean postoperative drain fluid amylase levels were as follows: on postoperative day 3 it was 262 U/mL (standard error of mean 69), on postoperative day 4 it was 112 U/mL (standard error of mean 47) and on postoperative day 5 it was 125 U/mL (standard error of mean 64). Only three (6/6, 50%) of these patients had clinical features suggestive of a leak and were found to have a pancreatic fistula on subsequent imaging. There was no correlation between the total or mean volumes of drainage and development of a pancreatic fistula.

Conclusion:  The drain fluid analysis did not provide additional information that was not already evident from the clinical picture of the patient. Drain fluid analysis had no effect on patients with a biochemical leak only. Patients who had a significant disruption of their pancreatic anastamosis did not need biochemical analysis as the character, that is, turbidity of the drain fluid was an equally reliable indicator of the underlying pathology.
PROTEOMIC ANALYSIS TO IDENTIFY BIOMARKER PROTEINS IN PANCREATIC DUCTAL ADENOCARCINOMA
Authors: Chung Jun Chul , Oh Mi Jung , Choi Seong Ho , Bae Chang Dae
Published: March 2008

Background:  Pancreatic ductal adenocarcinoma (PDAC) is the fifth most common cause of death from cancer in Korea. PDAC is difficult to diagnose at an early stage and even more difficult to cure. Thus, there is an urgent need to identify molecular targets for early diagnosis and effective treatment. The objectives of this study were to identify differentially expressed biomarker proteins of PDAC using proteomic analysis, to validate the identified biomarker proteins associated with carcinogenesis using western blot analysis and to evaluate clinical factors influencing expression of candidate biomarker proteins.

Methods:  In the present study, we carried out proteomic analysis in 10 pairs of PDAC specimens with matching adjacent normal tissues to clarify the different patterns of protein expression. The proteins were separated by high‐resolution 2‐D polyacrylamide gel electrophoresis (2D PAGE) and the differentially expressed proteins were identified by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Differential expression of candidate biomarker proteins associated with carcinogenesis was further validated using western blot analysis. Standard statistical analysis was carried out in an attempt to establish a correlation between clinical variables and expression of candidate biomarker proteins.

Results:  Analysis of PDAC and the adjacent normal tissues showed reproducibly similar proteomic patterns for each group. Approximately 700 spots each were seen by silver‐stained gels from both PDAC and normal tissues. Differentially expressed protein spots were gel digested and identified by MALDI‐TOF MS. Twenty‐five proteins were identified, of which five proteins (galectin‐1, enolase‐2, α‐1‐antitrypsin, N‐myc interactor, peroxiredoxin‐4) were previously reported as being differentially expressed either at the mRNA level or protein level in human cancer. The five proteins were selected for candidate biomarker proteins related to carcinogenesis. These proteins were further validated by western blot analysis. Among the candidate biomarker proteins, galectin‐1 expression was highly correlated to histology (P = 0.019), T stage (P = 0.047), N stage (P = 0.033) and American Joint Committee on Cancer stage (P = 0.011).

Conclusion:  Differentially expressed 25 proteins in PDAC were identified using proteomic analysis and five proteins related to carcinogenesis were validated by western blot analysis. galectin‐1 expression was highly correlated to tumour histology and stage.
Evidence for cleavage of lignin by a brown rot basidiomycete
Authors: Yelle Daniel J. , Ralph John , Lu Fachuang , Hammel Kenneth E.
Published: March 2008

Biodegradation by brown‐rot fungi is quantitatively one of the most important fates of lignocellulose in nature. It has long been thought that these basidiomycetes do not degrade lignin significantly, and that their activities on this abundant aromatic biopolymer are limited to minor oxidative modifications. Here we have applied a new technique for the complete solubilization of lignocellulose to show, by one‐bond 1H‐13C correlation nuclear magnetic resonance spectroscopy, that brown rot of spruce wood by Gloeophyllum trabeum resulted in a marked, non‐selective depletion of all intermonomer side‐chain linkages in the lignin. The resulting polymer retained most of its original aromatic residues and was probably interconnected by new linkages that lack hydrogens and are consequently invisible in one‐bond 1H‐13C correlation spectra. Additional work is needed to characterize these linkages, but it is already clear that the aromatic polymer remaining after extensive brown rot is no longer recognizable as lignin.
Who Makes the Choice? Rethinking the Role of Autonomy and Relatedness in Chinese Children’s Motivation
Authors: Bao Xue‐hua , Lam Shui‐fong
Published: March 2008

The importance of autonomy for children’s motivation in collectivistic cultures has been debated hotly. With the understanding that autonomy is not equivalent to freedom of choice, 4 studies addressed this debate by investigating how socioemotional relatedness, choice, and autonomy were related to Chinese children’s motivation. Study 1 (N = 56, mean age = 10.77 years), Study 2 (N = 58, mean age = 10.59), and Study 3 (N = 48, mean age = 10.53) found consistently that freedom of choice mattered less if children were socioemotionally close to the adults who made choices for them. However, Study 4 (N = 99, mean age = 11.27) showed that autonomy mattered at every level of socioemotional relatedness. These results suggested that socioemotional relatedness might have facilitated internalization and that children who did not have choice might still feel autonomous.
The Development of Recollection and Familiarity in Childhood and Adolescence: Evidence From the Dual‐Process Signal Detection Model
Authors: Ghetti Simona , Angelini Laura
Published: March 2008

Two experiments examined the development of recollection (recalling qualitative details about an event) and familiarity (recognizing the event) using the dual‐process signal detection model. In Experiment 1 (n = 117; ages 6, 8, 10, 14, and 18 years), recollection improved from childhood to adolescence after semantic encoding but not after perceptual encoding and familiarity improved from ages 6 to 8 regardless of encoding condition. In Experiment 2 (n = 56; ages 6, 8, and 10 years), long duration compared to short duration of semantic encoding increased familiarity but not recollection. Age‐related differences replicated those of Experiment 1, except no age difference in familiarity was found with long study duration. Overall, recollection and familiarity showed distinct developmental and functional characteristics. The dual‐process signal detection model proved promising for developmental investigations.
Promoting Broad and Stable Improvements in Low‐Income Children’s Numerical Knowledge Through Playing Number Board Games
Authors: Ramani Geetha B. , Siegler Robert S.
Published: March 2008

Theoretical analyses of the development of numerical representations suggest that playing linear number board games should enhance young children’s numerical knowledge. Consistent with this prediction, playing such a game for roughly 1 hr increased low‐income preschoolers’ (mean age = 5.4 years) proficiency on 4 diverse numerical tasks: numerical magnitude comparison, number line estimation, counting, and numeral identification. The gains remained 9 weeks later. Classmates who played an identical game, except for the squares varying in color rather than number, did not improve on any measure. Also as predicted, home experience playing number board games correlated positively with numerical knowledge. Thus, playing number board games with children from low‐income backgrounds may increase their numerical knowledge at the outset of school.
Controlling Parenting and Physical Aggression During Elementary School
Authors: Joussemet Mireille , Vitaro Frank , Barker Edward D. , Côté Sylvana , Nagin Daniel S. , Zoccolillo Mark , Tremblay Richard E.
Published: March 2008

The goal of the present study was to examine whether controlling parenting contributes to the problem of physical aggression. Developmental trajectories of children’s physical aggression were modeled from yearly teachers’ ratings, from ages 6 to 12. Multinomial logistic regressions (N = 1,508) served to identify risk factors that distinguish children who display different levels of physical aggression throughout grade school. Results revealed that being a boy and having a reactive temperament were important child predictors. Parental separation and an early onset of motherhood were also significant risk factors. Finally, mothers’ controlling parenting increased the odds of following the highest trajectory of physical aggression, above and beyond the previous risk factors.
Chronic administration of nevirapine during pregnancy: impact of pregnancy on pharmacokinetics
Authors: Capparelli EV , Aweeka F , Hitti J , Stek A , Hu C , Burchett SK , Best B , Smith E , Read JS , Watts H , Nachman S , Thorpe EM , Spector SA , Jimenez E , Shearer WT , Foca M , Mirochnick M ,   for the PACTG 1026S and P1022 Study Teams
Published: March 2008

Objectives

To determine the impact of pregnancy on the pharmacokinetics (PK) of nevirapine (NVP) during chronic dosing in HIV‐infected women and appropriate NVP dosing in this population.

Methods

Twenty‐six pregnant women participating in two open‐label Pediatric AIDS Clinical Trials Group studies (P1022 and P1026S) were evaluated. Each patient received 200 mg NVP every 12 h and had PK evaluations during the second or third trimester; these evaluations were repeated postpartum. Paired maternal and cord blood NVP concentrations were collected at delivery in nine patients. Ante‐ and postpartum comparisons were made using pairedt‐tests and using a ‘bioequivalence’ approach to determine confidence interval (CI).

Results

The average NVP Area Under the Curve (AUC) was 56 ± 13 mcg*h/mL antepartum and 61 ± 15 mcg*h/mL postpartum. The typical parameters ± standard error were apparent clearance (CL/F)=3.51 ± 0.18 L/h and apparent volume of distribution (Vd/F)=121 ± 19.8 L. There were no significant differences between antepartum and postpartum AUC or pre‐dose concentrations. The AUC ratio was 0.90 with a 90% CI of the mean equal to 0.80–1.02. The median (± standard deviation) cord blood to maternal NVP concentration ratio was 0.91 ± 0.90.

Conclusions

Pregnancy does not alter NVP PK and the standard dose (200 mg every 12 h) is appropriate during pregnancy.
A Government Ill Executed: The Depletion of the Federal Service
Authors: Light Paul C.
Published: March 2008

The federal government’s “quiet crisis” of the 1980s has become the “deafening crisis” of the early twenty‐first century. Virtually every measure of the state of the public service as envisioned by Alexander Hamilton has worsened over the past two decades. This lecture outlines Hamilton’s seven characteristics of an energetic federal service and examines recent trends in its decline. Although the federal service still executes an enormous agenda of important missions, it is increasingly frustrated in its work.
The Phenomenon of Collective Action: Modeling Institutions as Structures of Care
Authors: Lejano Raul
Published: March 2008

This essay develops a theory of how institutions can work through the web of social relationships that exist in a place rather than through formal, bureaucratic lines of authority. In contrast to models that characterize institutions as organizational structures, roles, and patterns of exchange, this model depicts institutions as constituted primarily through the active working and reworking of relationships. Rather than adopt the network literature’s focus on the overall pattern of relationships and exchanges carried out between policy actors, the author focuses directly on the nature of the relationships themselves and portrays the institution as the playing out of these relationships, employing Carol Gilligan’s notion of care. The model of care is used to analyze the evolution, unraveling, and restoration of resource management systems on the Turtle Islands in Southeast Asia. The model provides lessons for institution building, especially for community‐centered governance.
Advancing E‐Government: Financing Challenges and Opportunities
Authors: Chen Yu‐Che , Thurmaier Kurt
Published: March 2008

As e‐government evolves into the transactions stage, governments must grapple with how to finance the development of e‐transactions. The authors argue that the externalities effects of electronic transactions suggest they are appropriately financed by some combination of public investment and user charges. We propose a self‐financing model adhering to two basic requirements. A flexible pricing framework is the core of the self‐financing model, as it embodies both the firm’s and the government’s perspectives. We assess basic assumptions of the pricing framework using contingent valuation methodology and a statewide survey of more than 400 firms. The empirical estimates we develop of the willingness to pay for e‐transactions with state government and the theoretical discussion about the self‐financing model form the basis for prescribing policy recommendations.
Cardiac Correlates of Exercise Induced Pulmonary Hypertension in Patients with Chronic Heart Failure Due to Left Ventricular Systolic Dysfunction
Authors: Maréchaux Sylvestre , Pinçon Claire , Le Tourneau Thierry , De Groote Pascal , Huerre Clémence , Asseman Philippe , Van Belle Eric , Nevière Rémi , Bauters Christophe , Deklunder Ghislaine , LeJemtel Thierry H. , Ennezat Pierre V.
Published: March 2008

Background: Patients with chronic heart failure (CHF) due to left ventricular systolic dysfunction (LVSD) may develop pulmonary hypertension at rest and during exercise. The cardiac correlates of pulmonary hypertension have been ascertained in the resting state, but seldom during exercise in these patients. Aims: We sought to determine the cardiac correlates of exercise induced pulmonary hypertension in patients with LVSD by monitoring the estimated pulmonary artery systolic pressure (PASP) by continuous Doppler echocardiography during semirecumbent bicycle exercise. Methods: Eighty‐five patients (mean age 57 ± 13 years, 75% male) with CHF due to LVSD (LV ejection fraction [EF] <45%, mean LVEF 26 ± 8%) were studied. Results: Mitral effective regurgitant orifice area and E‐wave were independent predictors of resting PASP. Resting PASP and exercise induced changes in PASP were unrelated (r =−0.08, P = 0.45). Decrease in LV end‐systolic volume, increase in left atrial (LA) area, resting LV asynchrony, and decreased tricuspid annular plane systolic excursion (TAPSE) were independent predictors of exercise PASP. Conclusions: Resting LV asynchrony, impaired LV contractile reserve, and increase in LA dilatation correlate with the severity of exercise induced pulmonary hypertension in patients with CHF due to LVSD, while right ventricular systolic dysfunction is inversely related to the severity of exercise induced pulmonary hypertension.
Correlation between NT‐pro BNP Levels and Early Mitral Annulus Velocity (E′) in Patients with Non–ST‐Segment Elevation Acute Coronary Syndrome
Authors: Barbosa Marcia M. , Nunes Maria do Carmo P. , Castro Luiz Ricardo de Ataide , Nominato Luís Fernando R. da Silva , Alencar Maria Clara N. , Ribeiro Antonio L.P.
Published: March 2008

Acute coronary syndromes in the absence of ST‐segment elevation (NSTE‐ACS) are a heterogeneous entity in which early risk stratification is essential. Diastolic dysfunction is precocious and associated with poor prognosis. BNP has been recognized as a biochemical marker of ventricular dysfunction and ischemia. Objective: To investigate if there is correlation of NT pro‐BNP levels with diastolic dysfunction in patients with NSTE‐ACS. Methods: Fifty‐two patients with NSTE‐ACS admitted to the coronary unit were included. NT‐pro brain natriuretic hormone (BNP) levels and a Doppler echocardiogram were obtained in all and systolic and diastolic functions were analyzed. Their Doppler indexes were compared with those of 53 age‐ and sex‐matched controls, without heart failure symptoms and with normal ejection fraction (EF) and normal NT‐pro BNP levels. Results: Twenty‐four patients (46%) with unstable angina and 28 patients (54%) with acute myocardial infarction (AMI) were included. Mean EF was 55.9 ± 10.7% and mean NT‐pro BNP level was 835 ± 989 pg/ml. No mitral or pulmonary venous flow parameters of diastolic function correlated with NT‐pro BNP levels. E′/A′ correlated with NT‐pro BNP level in univariate analysis but, in a multivariate analysis, only the EF and the E′ showed negative correlation with the peptide level (r =−0.33, P = 0.024 and r =−0.29, P = 0.045, respectively). Thirteen patients presented with stage II diastolic dysfunction but the NT‐pro BNP level in these patients did not differ from the level in stage I patients. Conclusion: NT‐pro BNP levels are elevated in acute coronary syndromes, even in the absence of significant necrosis. Of all echocardiographic parameters investigated, only E′ and the EF correlated with the levels of NT‐pro BNP in this group of patients.
Estimating the Encounter Rate Variance in Distance Sampling
Authors: Fewster Rachel M. , Buckland Stephen T. , Burnham Kenneth P. , Borchers David L. , Jupp Peter E. , Laake Jeffrey L. , Thomas Len
Published: March 2008

SummaryThe dominant source of variance in line transect sampling is usually the encounter rate variance. Systematic survey designs are often used to reduce the true variability among different realizations of the design, but estimating the variance is difficult and estimators typically approximate the variance by treating the design as a simple random sample of lines. We explore the properties of different encounter rate variance estimators under random and systematic designs. We show that a design‐based variance estimator improves upon the model‐based estimator ofBuckland et al.(2001,Introduction to Distance Sampling.Oxford: Oxford University Press, p. 79) when transects are positioned at random. However, if populations exhibit strong spatial trends, both estimators can have substantial positive bias under systematic designs. We show that poststratification is effective in reducing this bias.
An Illicit Love Affair During the Third Reich: Who is My Grandfather?*
Authors: Milde‐Kellers Antje , Krawczak Michael , Augustin Christa , Boomgaarden‐Brandes Kerstin , Simeoni Eva , Kaatsch Hans‐Jürgen , Mühlbauer Bernd , Schuchardt Sven
Published: March 2008

Abstract:  More than 60 years after an illicit love affair had occurred between Erika H, wife of a Wehrmacht soldier, and a Polish slave worker during World War II, we could clarify the blood relationships of her daughter Uta. When Erika H had become pregnant both of the men could have fathered the child. Erika H was found guilty of fraternization and imprisoned at Ravensbrück concentration camp. She gave birth to Uta and died there in 1944. Uta survived the war as did Erika’s husband Gustav, who accepted Uta as his child. Blood samples from family members were taken and DNA extracted. A panel of 16 short tandem repeat (STR) loci were amplified and separated by capillary electrophoresis and the likelihoods calculated using the MLINK software. The combined genotypes yielded a cumulative likelihood ratio of over 200,000 against paternity of Gustav H. This case serves to illustrate the utility of STR profiles for complex deficiency kinship analysis.
Morphometric Criteria for Sexing Juvenile Human Skeletons Using the Ilium
Authors: Wilson Laura A. , MacLeod Norman , Humphrey Louise T.
Published: March 2008

Abstract:  Previous attempts to sex juvenile skeletons have focused on the application of qualitative or semi‐quantitative techniques. This study applies a variety of geometric morphometric methods, including eigenshape analysis, to this problem. Six metric criteria for the ilia were tested with the aim of investigating previous ideas concerning sexually diagnostic characters. This study uses 25 ilia from juveniles of known age and sex from Christ Church, Spitalfields, London. Ninety‐six percent of juvenile ilia were correctly identified as male or female using the shape of the greater sciatic notch. Identification accuracy is shown to improve with age for several criteria. Males were identified to a higher accuracy than females. Application of geometric techniques improves the understanding of the relationship between age, sex, and shape and the clarity with which these relationships can be quantified. Archaeological and forensic relevance of the results are discussed with recommendations for future application.