bluuebunny/crossref_metadata_2025 huggingface dataset:
The preparation and characterization of carboxylic acid‐coated silica nanoparticles
Authors: Cash Brandon M. , Wang Lei , Benicewicz Brian C.
Published: March 2012

The preparation of carboxylic acid‐coated silica nanoparticles was investigated. A monolayer of carboxylic acid residues with controllable graft density was anchored to the nanoparticle by a ring‐opening reaction with succinic anhydride. Poly(methacrylic acid) [poly(MAA)] grafted nanoparticles were prepared via a polymerization–deprotection strategy. Tert‐butyl methacrylate was polymerized from the surface of silica nanoparticles in a predictable manner and with excellent control over the molecular weight distribution. Subsequent removal of the tert‐butyl group resulted in poly (MAA) grafted nanoparticles. The polymer nanoparticles were also functionalized with dyes, which may be useful in tracking the particles in biological systems. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Internal Structure of a Lithalsa in the Akkol Valley, Russian Altai Mountains
Authors: Iwahana Go , Fukui Kotaro , Mikhailov Nikolai , Ostanin Oleg , Fujii Yoshiyuki
Published: March 2012

Perennial frost mounds are present near the edges of ponds located on the terrace between the mountain flank and a valley‐bottom lake in the Akkol valley of the Russian Altai Mountains. These mounds are 10–50 m in diameter and 3–6 m in height. We describe one mound, identified as a lithalsa, which had been eroded so as to expose almost its entire vertical cross‐section, revealing its internal structure. The frozen core consisted mainly of soil segments suspended in reticulate ice lenses with a mean thickness of 11–48 mm and a maximum thickness of about 160 mm. The shapes of the soil segments matched their neighbours. Other features included soil segments suspended in the ice veins shaped like ‘En echelon gash veins’, and the presence of a radial structure of ice‐rich and sediment‐rich frozen bands. These features all suggest the greater importance of a differential stress field during heaving of the mound and after ice segregation, compared to the thermal gradient and water supply. Copyright © 2012 John Wiley & Sons, Ltd.
Geographic variability in response to azinphos‐methyl in field‐collected populations of Cydia pomonella (Lepidoptera: Tortricidae) from Argentina
Authors: Soleño Jimena , Anguiano Olga L , Cichón Liliana B , Garrido Silvina A , Montagna Cristina M
Published: March 2012

BACKGROUND: Resistance to insecticides has been related to application history, genetic factors of the pest and the dynamic within the treated area. The aim of this study was to assess the geographic variation in azinphos‐methyl response and the role of esterase and cytochrome P450 monooxygenase enzymes in codling moth populations collected within different areas of the Río Negro and Neuquén Valley, Argentina.

RESULTS: Diapausing field‐collected populations showed resistance ratios at the LC50 that were 0.7–8.7 times higher than that of the susceptible strain. Mean esterase (EST) and cytochrome P450 monooxygenase activities (expressed as α‐N min−1 mg−1 prot−1 and pg 7‐OHC insect−1 min−1 respectively) were significantly correlated with LD50 values from the field‐collected populations. In addition, azinphos‐methyl response was associated with the geographic area where the insect population was collected: populations from isolated and more recent productive areas presented significantly lower resistance ratios in comparison with populations from older and more intensive productive areas.

CONCLUSION: The populations assayed presented different resistance levels to azinphos‐methyl. The response was highly correlated with the orchard's geographic location. EST and ECOD activities were involved in azinphos‐methyl response in the given region. Copyright © 2012 Society of Chemical Industry
EDESR of impurity centers in nanostructures inserted in silicon microcavities
Authors: Bagraev Nikolay , Danilovsky Eduard , Gehlhoff Wolfgang , Gets Dmitry , Klyachkin Leonid , Kudryavtsev Andrey , Kuzmin Roman , Malyarenko Anna , Mashkov Vladimir , Romanov Vladimir
Published: March 2012

We present the first findings of the new electrically detected electron spin resonance technique (EDESR) which reveal single point defects in the ultra‐narrow silicon quantum wells (Si‐QW) confined by the superconductor δ‐barriers. This technique allows the ESR identification without the application of the external cavity as well as the high frequency (hf) source and recorder, with measuring the only magnetoresistance caused by the hf emission from the δ‐barriers in the presence of the microcavity embedded in the Si‐QW plane. The new resonant positive magnetoresistance data are interpreted here in terms of the interference transition in the diffusive transport of free holes respectively between the weak antilocalization regime in the range of magnetic fields far from the ESR of a paramagnetic point defect located inside or near the conductive channel and the weak localization regime in the range of magnetic fields corresponding to the ESR of that defect. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Second‐harmonic generation microscopy of ferroelectric organic conductor using hydrostatic pressure apparatus with Ar as a heat sink
Authors: Yamamoto Kaoru , Kowalska Aneta Aniela , Yakushi Kyuya
Published: March 2012

Low temperature measurements of optical second‐harmonic generation (SHG) were performed for organic conductors showing ferroelectric charge ordering. To avoid the heating due to focused laser beam without applying mechanical stress to the samples, the organic crystals were mounted in liquid argon heat‐transfer medium. The noble gas was sealed in a diamond‐anvil cell type pressure cell, though the pressure was regulated around ambient level. The technique of the low temperature nonlinear optical microscopy is presented. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First principles calculations of pKa values of amines in aqueous solution: Application to neurotransmitters
Authors: Rebollar‐Zepeda Aida Mariana , Galano Annia
Published: March 2012

A systematic search for computational strategies able to accurately predict pKa values of protonated amines (HA+) has been performed. Thermodynamic cycles have been used in conjunction with the cluster‐continuum model, including up to eight explicit water molecules per system. The calculations have been performed with nine different methods within the density functional theory (DFT), and with MP2. It was found that including one explicit water molecule in the vicinity of the protonated site is highly important for obtaining accurate results. We recommend the F2 reaction scheme [HA+(H2O) + 3H2O = A + H3O+(3H2O)], combined with M05‐2X/6‐311++G(d,p) calculations. This particular combination produces mean unsigned errors (MUE) equal to 0.54 for all the tested amines, and 0.51 pKa units for the studied neurotransmitters. Moreover it was found to be the only one that systematically leads to errors lower than, or very close to, 1 unit of pKa for every one of the studied species, with the maximum error equal to 1.09 pKa units. This scheme has the additional advantages of being computationally feasible for amines of relative large size, independent of experimental values, and free of fitting‐based corrections. In addition the high influence of the reference acid of choice, in the proton exchange scheme (D), on the quality of the pKa values of amines is discussed. © 2012 Wiley Periodicals, Inc.
Large‐scale DFT calculations in implicit solvent—A case study on the T4 lysozyme L99A/M102Q protein
Authors: Dziedzic Jacek , Fox Stephen J. , Fox Thomas , Tautermann Christofer S. , Skylaris Chris‐Kriton
Published: March 2012

Recently, variants of implicit solvation models for first principles electronic structure calculations based on a direct solution of the nonhomogeneous Poisson equation in real space have been developed. These implicit solvation models are very elegant from a physical point of view as the solute cavity is defined directly via isosurfaces of the electronic density, and the molecular charge is polarized self‐consistently by the reaction field of the dielectric continuum which surrounds the solute. Nevertheless, the implementation of these models is technically complex and requires great care. A certain level of care is required from users of such models as a number of numerical parameters need to be given appropriate values to obtain the most accurate and physically relevant results. Here, we describe in what parts of the solvent model each of these numerical parameters is involved and present a detailed study of how they can affect the calculation, using the solvation model which has been implemented in the ONETEP program for linear‐scaling density functional theory (DFT) calculations. As ONETEP is capable of DFT calculations with thousands of atoms, we focus our investigation of the numerical parameters with a case study on protein–ligand complexes of the entire 2602‐atom T4 Lysozyme L99/M102Q protein. We examine effects on solvation energies and binding energies, which are critical quantities for computational drug optimization and other types of biomolecular simulations. We propose optimal choices of these parameters suitable for routine “production” calculations. © 2012 Wiley Periodicals, Inc.
Size‐Dependent Fracture Mode Transition in Copper Nanowires
Authors: Peng Cheng , Zhan Yongjie , Lou Jun
Published: March 2012

In situ uni‐axial tensile tests of single‐crystalline copper nanowires are performed using a micromechanical device inside a scanning electron microscope chamber. The single‐crystalline copper nanowires are synthesized by solvothermal processes, and the growth direction along the wire axis is the <110> orientation as confirmed by transmission electron microscopy (TEM) selected area diffraction (SAD) analysis. The fracture strengths of copper nanowires are found to be much higher than that of bulk copper. More interestingly, both ductile and brittle‐like fracture modes are found in the same batch of fabricated nanowires, and the fracture modes appear to be dependent on the diameters of tested nanowires. From the analysis of fracture surfaces, sample morphologies and corresponding stress–strain curves, the competition between deformation and fracture mechanisms controlled by initial defects density and by the probability of dislocation interactions is attributed to this intriguing size‐dependent fracture mode transition.
Compensation for cranial spill‐in into the cerebellum improves quantitation of striatal dopamine D2/3 receptors in rats with prolonged [18F]‐DMFP infusions
Authors: Mille Erik , Cumming Paul , Rominger Axel , La Fougère Christian , Tatsch Klaus , Wängler Björn , Bartenstein Peter , Böning Guido
Published: March 2012

The condition of steady‐state receptor binding in positron emission tomography (PET) studies is best obtained through the use of a bolus plus steady‐infusion paradigm. This is a particularly important consideration in the context of in vivo competition studies, where a pharmacological challenge can be administered during the interval of steady‐state ligand binding, as in the case of [11C]‐raclopride studies with amphetamine challenge. However, the short half‐life of 11C imposes limits on the practical duration of constant infusions. Therefore, we chose to test [18F]‐DMFP as a tracer for dopamine D2/3 receptors in rat striatum in the paradigm. Using a conventional bolus injection, the [18F]‐DMFP BPND was 3.8 in striatum of anesthetized rats. When followed by a constant infusion, we obtained quasi‐stable BPND estimates of 4.5 within an interval of 45 min. During infusions lasting up to 4 h, BPND declined progressively. This seemed due to the progressive spill‐in of radioactivity from the cranium to the cerebellum reference region, despite optimized iterative reconstruction of the images. Therefore, we propose a new concept of compensation for this spill‐in effect using pharmacokinetic considerations, without requiring high‐resolution anatomical images. Challenge with amphetamine (1 and 4 mg/kg) evoked an ∼25% reduction in BPND. There was no clear evidence of dose‐dependence in the striatal‐binding changes, despite the considerably greater physiological effect, as documented by ECG. Thus, the general applicability of the bolus plus infusion method with [18F]‐DMFP for small animal studies is impeded by the substantial labeling of the cranium. The cranial uptake was linear, indicating first‐order kinetics for the enzymatic defluorination of the tracer. Based on this phenomenon, we developed an analytic method compensating for the effects of progressive cranial labeling on the estimation of specific binding in striatum. Synapse, 2012. © 2012 Wiley Periodicals, Inc.
Sonographic predictors of surgery in fetal coarctation of the aorta
Authors: Jowett V. , Aparicio P. , Santhakumaran S. , Seale A. , Jicinska H. , Gardiner H. M.
Published: March 2012

Objectives

Isolated fetal coarctation of the aorta (CoA) has high false‐positive diagnostic rates by cardiologists in tertiary centers. Isthmal diameter Z‐scores (I), ratio of isthmus to duct diameters (I:D), and visualization of CoA shelf (Shelf) and isthmal flow disturbance (Flow) distinguish hypoplastic from normal aortic arches in retrospective studies, but their ability to predict a need for perinatal surgery is unknown. The aim of this study was to determine whether these four sonographic features could differentiate prenatally cases which would require neonatal surgery in a prospective cohort diagnosed with CoA by a cardiologist.

Methods

From 83 referrals with cardiac disproportion (January 2006 to August 2010), we identified 37 consecutive fetuses diagnosed with CoA. Measurements of I and I:D were made and the presence of Shelf or Flow recorded. Sensitivity, specificity and areas under receiver–operating characteristics curves, using previously reported limits of I < − 2 and I:D < 0.74, as well as Shelf and Flow were compared at first and final scan. Associations between surgery and predictors were compared using multivariable logistic regression and changes in measurements using ANCOVA.

Results

Among the 37 fetuses, 30 (81.1%) required surgery and two with an initial diagnosis of CoA were revised to normal following isthmal growth, giving an 86% diagnostic accuracy at term. The median age at first scan was 22.4 (range. 16.6–7.0) weeks and the median number of scans per fetus was three (range, one to five). I < − 2 at final scan was the most powerful predictor (odds ratio, 3.6 (95% CI, 0.47–27.3)). Shelf was identified in 66% and Flow in 50% of fetuses with CoA.

Conclusion

Incorporation of these four sonographic parameters in the assessment of fetuses with suspected CoA at a tertiary center resulted in better diagnostic precision regarding which cases would require neonatal surgery than has been reported previously. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Detection of intracavitary uterine pathology using offline analysis of three‐dimensional ultrasound volumes: interobserver agreement and diagnostic accuracy
Authors: Van den Bosch T. , Valentin L. , Van Schoubroeck D. , Luts J. , Bignardi T. , Condous G. , Epstein E. , Leone F. P. , Testa A. C. , Van Huffel S. , Bourne T. , Timmerman D.
Published: March 2012

Objective

To estimate the diagnostic accuracy and interobserver agreement in predicting intracavitary uterine pathology at offline analysis of three‐dimensional (3D) ultrasound volumes of the uterus.

Methods

3D volumes (unenhanced ultrasound and gel infusion sonography with and without power Doppler, i.e. four volumes per patient) of 75 women presenting with abnormal uterine bleeding at a ‘bleeding clinic’ were assessed offline by six examiners. The sonologists were asked to provide a tentative diagnosis. A histological diagnosis was obtained by hysteroscopy with biopsy or operative hysteroscopy. Proliferative, secretory or atrophic endometrium was classified as ‘normal’ histology; endometrial polyps, intracavitary myomas, endometrial hyperplasia and endometrial cancer were classified as ‘abnormal’ histology. The diagnostic accuracy of the six sonologists with regard to normal/abnormal histology and interobserver agreement were estimated.

Results

Intracavitary pathology was diagnosed at histology in 39% of patients. Agreement between the ultrasound diagnosis and the histological diagnosis (normal vs abnormal) ranged from 67 to 83% for the six sonologists. In 45% of cases all six examiners agreed with regard to the presence/absence of intracavitary pathology. The percentage agreement between any two examiners ranged from 65 to 91% (Cohen's κ, 0.31–0.81). The Schouten κ for all six examiners was 0.51 (95% CI, 0.40–0.62), while the highest Schouten κ for any three examiners was 0.69.

Conclusion

When analyzing stored 3D ultrasound volumes, agreement between sonologists with regard to classifying the endometrium/uterine cavity as normal or abnormal as well as the diagnostic accuracy varied substantially. Possible actions to improve interobserver agreement and diagnostic accuracy include optimization of image quality and the use of a consistent technique for analyzing the 3D volumes. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Unusually low inversion
Authors: Lapworth Alan
Published: March 2012

Readers are encouraged to submit letters for possible publication. Letters can be submitted either electronically through the system used for articles, by email attachment to weather@wiley.com or by post, as shown on the Contents page. The Letters Editor reserves the right to edit any letter.
MicroRNA degradation and turnover: regulating the regulators
Authors: Zhang Zhuo , Qin Yong‐Wen , Brewer Gary , Jing Qing
Published: March 2012

MicroRNAs (miRNAs) are endogenous, small noncoding RNAs that play important regulatory roles in gene expression. The control of miRNA biogenesis has been well characterized, but their degradation is not fully understood. Recent discoveries indicate that miRNAs have a long life span in general. However, rapid turnover dynamics of miRNAs in a variety of specific cellular contexts has been documented, as well as the requirement of sequence elements for miRNA decay. Furthermore, several ribonucleases that degrade miRNAs have been identified. Here, we discuss the cellular contexts and biochemical mechanisms of miRNA decay, together with several prominent questions in this field. WIREs RNA 2012, 3:593–600. doi: 10.1002/wrna.1114

This article is categorized under:

RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms

Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs
Holographic predictions for cosmological 3-point functions
Authors: Bzowski Adam , McFadden Paul , Skenderis Kostas
Published: March 2012

Abstract

We present the holographic predictions for cosmological 3-point correlators, involving both scalar and tensor modes, for a universe which started in a non-geometric holographic phase. Holographic formulae relate the cosmological 3-point functions to stress tensor correlation functions of a holographically dual three-dimensional non-gravitational QFT. We compute these correlators at 1-loop order for a theory containing massless scalars, fermions and gauge fields, and present an extensive analysis of the constraints due to Ward identities showing that they uniquely determine the correlators up to a few constants. We define shapes for all cosmological bispectra and compare the holographic shapes to the slow-roll ones, finding that some are distinguishable while others, perhaps surprisingly, are not. In particular, for three gravitons, we are able to recover the slow-roll shapes exactly.
On BPS bounds in D = 4 N = 2 gauged supergravity II: general matter couplings and black hole masses
Authors: Hristov Kiril
Published: March 2012

Abstract

We continue the analysis of BPS bounds started in [1], extending it to the full class of N = 2 gauged supergravity theories with arbitrary vector and hypermultiplets. We derive the general form of the asymptotic charges for asymptotically flat (M4), anti-de Sitter (AdS4), and magnetic anti-de Sitter (mAdS4) spacetimes. Some particular examples from black hole physics are given to explicitly demonstrate how AdS and mAdS masses differ when solutions with non-trivial scalar profiles are considered.
A Preliminary Comparison Study of Two Noncrosslinked Biologic Meshes Used in Complex Ventral Hernia Repairs
Authors: Janfaza Mona , Martin Maureen , Skinner Ruby
Published: March 2012

Background

The biologic materials currently available for hernia repairs are costly and there are limited statistics on recurrences and rates of infection in connection with their use in complex cases.

Methods

We performed a retrospective review and comparison of two types of biologic mesh used at our institution for abdominal hernia repairs spanning a 1‐year period. Demographic data and outcomes relating to surgical site infections, hernia recurrences, and mortality were analyzed. Of the 35 patients in the study, 23 patients (Group I) were managed with SurgiMend, a neonatal bovine mesh, and 12 patients (Group II) were managed with Flex HD, a human‐derived mesh.

Results

The study cohorts met criteria for high‐risk stratification based on body mass index, comorbid conditions, and a high prevalence of contaminated wounds. The overall surgical site infection rate was 17 % for Group I and 50 % for Group II. These differences reached statistical significance when comparing superficial infections but not for deep infections with mesh involvement. Hernia recurrences in Group I were 5 % compared to 33 % in Group II. No deaths were observed.

Conclusions

These preliminary data demonstrate promising short‐term outcomes for high‐risk complex hernias repaired with biologic mesh, particularly SurgiMend, but the long‐term durability of these biological materials is yet to be determined.
Concentration of Stearidonic Acid in Free Fatty Acids Form from Modified Soybean Oil by Selective Esterification with Dodecanol
Authors: Vázquez Luis , Kleiner Leslie , Akoh Casimir C.
Published: March 2012

The concentration of stearidonic acid (SDA, 18:4 n‐3) in free fatty acids (FFA) formed by selective esterification with dodecanol (lauryl alcohol) was studied. For this purpose, modified soybean oil (initial SDA content, ~23 %) was converted into its corresponding FFA by chemical hydrolysis. In a second step, the resulting FFA were esterified with dodecanol. Process variables such as the type of biocatalyst (lipase), substrate molar ratio and amount of lipase were evaluated. The best SDA concentration (58 %) and recovery (94 %) were attained by performing the esterification reaction for 4 h, with 1:1 molar ratio (dodecanol:FFA), and 5 % (w/w) Candida rugosa lipase as biocatalyst. It was observed that SDA was concentrated in the unesterified fraction.
Hip impingement in slipped capital femoral epiphysis: A changing perspective
Authors: Hosalkar Harish S. , Pandya Nirav K. , Bomar James D. , Wenger Dennis R.
Published: March 2012

Background

Femoroacetabular impingement (FAI) as a result of slipped capital femoral epiphysis (SCFE) has recently gained significant attention. Seen as an intermediate step toward the development of early osteoarthritis, symptomatic FAI develops in SCFE patients who have residual hip deformity characterized by relative posterior and medial displacement of the capital femoral epiphysis, leading to an anterolateral prominence of the metaphysis which abuts on the acetabular rim. This results in a decreased range of hip motion as well as progressive labral damage and articular cartilage injury, which cause symptoms of FAI. All degrees of slips from mild to severe can develop impingement.

Methods

The existing literature on the subject was thoroughly reviewed and all levels of studies that have made any meaningful changes to clinical practice were considered.

Results

Based on the literature review, current practice trends, and our own institutional practice pattern, all treatment options for SCFE in the impingement era have been presented with an open discussion regarding potential benefits and limitations.

Conclusions

Several surgical options exist for the SCFE patient who develops FAI. These are largely determined by the degree of deformity present and severity of the initial slip. Extraarticular (intertrochanteric, base of the neck) as well as subcapital osteotomies can be utilized with a goal of restoring proximal femoral anatomy in order to minimize the effect of the anterolateral prominence in more severe deformities. Patients with milder deformities can undergo osteochondroplasty of the femoral head and neck to remove impinging structures via either an open or arthroscopic approach. Also, proximal femoral osteotomy and open head–neck recontouring can be combined. Finally, patients who develop pain very early after in situ pinning must also be examined for potential iatrogenic screw-head impingement as a source of their pain and decreased hip motion, in addition to abnormalities in the proximal femoral anatomy. There are many centers that are approaching acute unstable SCFE patients as well as the more displaced stable cases with open reduction techniques that seem to be demonstrating good mid-term results. The goal of treatment is to improve patient function, alleviate hip pain, and to delay or prevent the development of early degenerative changes in adolescents and young adults. Prospective multi-center studies will be necessary so as to determine what methods work best in treatment and delay the onset and progression of osteoarthritis.

Level of evidence

V.
Medical and environmental risk factors associated with frontotemporal dementia: A case‐control study in a veteran population
Authors: Kalkonde Yogeshwar V. , Jawaid Ali , Qureshi Salah U. , Shirani Peyman , Wheaton Michael , Pinto‐Patarroyo Gineth P. , Schulz Paul E.
Published: March 2012

Background

Compared with other major dementias, very little is known about the medical and environmental risk factors associated with frontotemporal dementia (FTD). In this study, we evaluated medical and environmental disorders associated with FTD in a veteran population.

Methods

The medical records of 845 consecutive veterans who were evaluated for cognitive and/or behavioral complaints at a cognitive disorders clinic in an academic medical center between March 1, 2003, and June 30, 2008, were reviewed and 554 patients received a diagnosis of dementia. Medical disorders and environmental risk factors in 63 patients with behavioral variant of FTD were compared with 491 patients with non‐FTD dementias.

Results

The prevalence of traumatic brain injury (TBI) was significantly greater in patients with FTD versus those with non‐FTD dementias (12.7% vs 3.5%; P < .05). The FTD group also had a lower prevalence of heart disease (19.0% vs 36.7%; P < .05) and cerebrovascular diseases (12.7% vs 26.1%; P < .05), although the prevalence of vascular risk factors was comparable between FTD and non‐FTD dementia groups: hypertension (65.1% vs 68.2%), diabetes (31.7% vs 26.9%), hyperlipidemia (42.9% vs 48.9%), and tobacco use (7.9% vs 8.8%; P > .05 for all). In multivariate analysis, the risk for FTD was increased in patients with TBI (OR, 4.4; 95% CI, 1.6–11.8). The risk for FTD was marginally decreased in patients with heart disease (OR, 0.4; 95% CI, 0.3–0.96).

Conclusions

In a clinical sample of veterans, risk of FTD was increased in patients with TBI and marginally decreased in patients with heart disease. Prospective studies are needed to confirm these associations temporally and to identify their underlying mechanisms.
Alzheimer's disease: Pathogenesis and prevention
Authors: Braak Heiko , Del Tredici Kelly
Published: March 2012

Tau lesions (pretangles, neuropil threads, neurofibrillary tangles) in select neuronal types are essential to the pathogenesis of Alzheimer's disease. Pretangle formation marks the beginning of the pathological process and is of particular interest because it is temporally closer to the prevailing conditions that induce the pathological process underlying Alzheimer's disease in contrast to late‐stage disease. However, not all pretangles convert into neurofibrillary tangles. We propose that the development of tau lesions in Alzheimer's disease is traceable to differences between early‐ versus late‐maturing oligodendrocytes and to the exceptionally protracted myelination of late‐developing portions of the human brain. Conclusions drawn from these considerations should encourage development of new preventative and disease‐modifying strategies.
How does justice matter in achieving buyer–supplier relationship performance?
Authors: Liu Yi , Huang Ying , Luo Yadong , Zhao Yang
Published: March 2012

This study presents an analysis exploring how four types of justice (distributive, procedural, interpersonal, and informational) influence dyadic relationship performance in the buyer–supplier context. Underpinned by loose coupling theory, we build a mediating framework in which we propose that a high level of justice (or fairness) as mutually perceived by both parties drives buyer–supplier relationship performance through bolstered coupling links in mutual knowledge sharing, continuous commitment, and relationship investment. Our survey of 216 paired manufacturers (suppliers) and distributors (buyers) in China generally supports this argument, leading to a conclusion that justice is not a direct determinant of buyer–supplier performance but a critical conduit that nourishes mid‐range coupling behaviors, which in turn promotes a successful relationship. Based on findings from this study, firms are encouraged to endorse all four kinds of justice in managing supply chain relationships. However, when constrained by resources, the recommendation for managers is to focus on achieving a high level of perceptual convergence on procedural justice and informational justice with the exchange partner, because mutual perceptions of procedural and informational justice have the strongest effects on coupling behaviors and buyer–supplier relationship performance.
On the transition from finite-volume negatively buoyant releases to continuous fountains
Authors: Myrtroeen O. J. , Hunt G. R.
Published: March 2012

An experimental investigation to identify the source conditions that distinguish finite-volume negatively buoyant fluid projectile behaviour from fountain behaviour in quiescent environments of uniform density is described. Finite-volume releases are governed by their source Froude number ${\mathit{Fr}}_{D} $ and the aspect ratio $L/ D$ of the release, where $L$ denotes the length of the column of fluid dispensed vertically from the nozzle of diameter $D$. We establish the influence of $L/ D$ on the peak rise heights of a release formed by dispensing saline solution into fresh water for $0\lesssim {\mathit{Fr}}_{D} \lesssim 6$ and $0\lesssim L/ D\lesssim 34$. Within these ranges, we determine the source conditions for which a flow may be regarded, in terms of the initial rise height attained, as either finite-volume or continuous flux. The critical aspect ratio $ \mathop{ (L/ D)} \nolimits _{f} $, for a given ${\mathit{Fr}}_{D} $, which when exceeded no longer influenced release behaviour, led to the determination of $\{ {\mathit{Fr}}_{D} , \mathop{ (L/ D)} \nolimits _{f} \} $ paired source conditions that give rise to solely Froude-number-dependent, i.e. fountain-like, behaviour. As such, we make the link between finite-volume releases and continuous fountains. The $\{ {\mathit{Fr}}_{D} , \mathop{ (L/ D)} \nolimits _{f} \} $ pairs led us directly to the classification of a $\{ {\mathit{Fr}}_{D} , L/ D\} $ space from which source conditions giving rise to either negatively buoyant projectiles or fountains may be readily identified. The variation of $ \mathop{ (L/ D)} \nolimits _{f} $ with ${\mathit{Fr}}_{D} $ corresponds closely to established fountain regimes of very weak, weak and forced fountains. Moreover, our results indicate that the formation or otherwise of a primary vortex, as fluid is ejected, has a profound influence on the length of the dispensed fluid column that is necessary to achieve rise heights equal to fountain rise heights.
On the generation of steady streamwise streaks in flat-plate boundary layers
Authors: Fransson Jens H. M. , Talamelli Alessandro
Published: March 2012

A study on the generation and development of high-amplitude steady streamwise streaks in a flat-plate boundary layer is presented. High-amplitude streamwise streaks are naturally present in many bypass transition scenarios, where they play a fundamental role in the breakdown to turbulence process. On the other hand, recent experiments and numerical simulations have shown that stable laminar streamwise streaks of alternating low and high speed are also capable of stabilizing the growth of Tollmien–Schlichting waves as well as localized disturbances and to delay transition. The larger the streak amplitude is, for a prescribed spanwise periodicity of the streaks, the stronger is the stabilizing mechanism. Previous experiments have shown that streaks of amplitudes up to 12 % of the free stream velocity can be generated by means of cylindrical roughness elements. Here we explore the possibility of generating streaks of much larger amplitude by using a row of miniature vortex generators (MVGs) similar to those used in the past to delay or even prevent boundary layer separation. In particular, we present a boundary layer experiment where streak amplitudes exceeding 30 % have been produced without having any secondary instability acting on them. Furthermore, the associated drag with the streaky base flow is quantified, and it is demonstrated that the streaks can be reinforced by placing a second array of MVGs downstream of the first one. In this way it is possible to make the control more persistent in the downstream direction. It must be pointed out that the use of MVGs opens also the possibility to set up a control method that acts twofold in the sense that both transition and separation are delayed or even prevented.
STRONG AND WEAK WEIGHTED NORM INEQUALITIES FOR THE GEOMETRIC FRACTIONAL MAXIMAL OPERATOR
Authors: BARZA SORINA , NICULESCU CONSTANTIN P.
Published: March 2012

We characterise the strong- and weak-type boundedness of the geometric fractional maximal operator between weighted Lebesgue spaces in the case 0<p≤q<∞, generalising and improving some older results.
A NOTE ON AUTOMORPHISMS OF FINITE p-GROUPS
Authors: GHORAISHI S. MOHSEN
Published: March 2012

Let p be an odd prime and let G be a finite p-group such that xZ(G)⊆xG, for all x∈G∖Z(G), where xG denotes the conjugacy class of x in G. Then G has a noninner automorphism of order p leaving the Frattini subgroup Φ(G) elementwise fixed.
Context, Equality, and Aboriginal Compensation Claims
Authors: Hendrix Burke A.
Published: March 2012

ABSTRACT: Jeremy Waldron argues that the historical ownership rights of Aboriginal peoples can be superseded, yet acknowledges that programs of historically grounded compensation are justifiable in the absence of widespread redistribution. This article argues that existing states lack social justice programs of the requisite kind, and that they will continue to do so in the foreseeable future. Moreover, even the best-designed programs will be far more ambiguous than Waldron encourages us to recognize, given the unavoidability of inheritance-based inequalities. The article argues that philosophers should pay special attention to political context when evaluating the claims of socially vulnerable populations such as Aboriginal peoples.
ON SS-SUPPLEMENTED SUBGROUPS OF FINITE GROUPS AND THEIR PROPERTIES
Authors: GUO XIUYUN , LU JIAKUAN
Published: March 2012

A subgroup H of a finite group G is called SS-supplemented in G if there exists a subgroup K of G such that HK = G and H ∩ K is S-quasinormal in K. In this paper, we characterize the finite groups in which every subgroup is SS-supplemented and the influence of SS-supplementation of some subgroups on the structure of finite groups is considered. Some recent results on SS-quasinormal subgroups and C-supplemented subgroups are strengthened and enriched.
ON THE DOUBLE TRANSFER AND THE f-INVARIANT
Authors: POWELL GEOFFREY
Published: March 2012

The purpose of this paper is to investigate the algebraic double S1-transfer, in particular the classes in the two-line of the Adams–Novikov spectral sequence which are the image of comodule primitives of the MU-homology of ℂP∞ × ℂP∞ via the algebraic double transfer. These classes are analysed by two related approaches: the first, p-locally for p ≥ 3, by using the morphism induced in MU-homology by the chromatic factorisation of the double transfer map together with the f′-invariant of Behrens (for p ≥ 5) (M. Behrens, Congruences between modular forms given by the divided β-family in homotopy theory, Geom. Topol.13(1) (2009), 319–357). The second approach (after inverting 6) uses the algebraic double transfer and the f-invariant of Laures (G. Laures, The topological q-expansion principle, Topology38(2) (1999), 387–425).
ANOTHER LAW FOR 3-METABELIAN GROUPS
Authors: BUSSMAN CHRISTINE , JACKSON DAVID A.
Published: March 2012

We show that [z, y]−1[z, x]−1[y, x]−1[z, y][z, x][y, x] = 1 is another defining law for the variety of 3-metabelian groups.
A NEW QUANTITY IN RIEMANN-FINSLER GEOMETRY
Authors: MO XIAOHUAN , SHEN ZHONGMIN , LIU HUAIFU
Published: March 2012

In this note, we study a new Finslerian quantityĈdefined by the Riemannian curvature. We prove that the new Finslerian quantity is a non-Riemannian quantity for a Finsler manifold with dimensionn= 3. Then we study Finsler metrics of scalar curvature. We find that theĈ-curvature is closely related to the flag curvature and theH-curvature. We show thatĈ-curvature gives, a measure of the failure of a Finsler metric to be of weakly isotropic flag curvature. We also give a simple proof of the Najafi-Shen-Tayebi' theorem.
Beyond the Canonical and the Apocryphal Books, the Presence of a Third Category: The Books Useful for the Soul
Authors: Bovon François
Published: March 2012

I like tennis—both to play and to watch it.1 Nothing is more pleasant than watching an exchange between Federer and Nadal. There is a similar kind of exchange that has been going on in this country in recent years. On one side, there are evangelical New Testament scholars; on the other, liberal scholars working on early Christianity. In the camp of the evangelicals, Ben Witherington,2 Craig A. Evans,3 and Darrell L. Bock4 are playing a defensive game, accusing the others of constituting a “new school,”5 one that prefers heresy over orthodoxy and promotes diversity where unity once was. In the camp of the critics, Elaine Pagels promotes the spirituality of the Gospel of Thomas; 6 Bart D. Ehrman's Lost Christianities flies in the face of his opponents;7 and Marvin Meyer considers the Gospel of Judas a valuable work that reveals in the mind of the dark apostle knowledge of the divine realm.8
Review Essay Finding God with–and through–the Other
Authors: Ram-Prasad Chakravarthi
Published: March 2012

In a bold and complex book that refers to rigorous and close exegesis but progresses through cultivated intuition, Francis X. Clooney, S.J., the Parkman Professor of Divinity and Professor of Comparative Theology and Director of the Center for the Study of World Religions at Harvard Divinity School, locates himself—and asks his readers to place themselves—in a place at once secure and vulnerable, liminal and yet centered, the place at which traditions blur at their boundaries and insights grace us from all directions. I imagine that it can be an unsettling and off-putting read to anyone for whom faith is an undaunted rejection of multiple traditions and theology a xenologically bound discipline. But for those who look at the diversity of the human condition in wonderment and seek theological methods suitable for that diversity, it offers many lessons; these may be unsettling, but in a way that sharpens their own balance, and quickens their own search. The book as a whole seeks to provide a programmatic but grounded case for the discipline of comparative theology, which is in many ways a relatively recent field in the academy.
Audiological monitoring for ototoxic tuberculosis, human immunodeficiency virus and cancer therapies in a developing world setting
Authors: Harris T , Peer S , Fagan J J
Published: March 2012

Ototoxic drugs are widely used in the developing world, without audiological monitoring. Epidemiological data on ototoxic deafness are lacking for developing countries. The public health aspect of ototoxicity is often overlooked, to the detriment of the individual patient. This paper reviews ototoxic hearing loss, particularly in sub-Saharan Africa, and also assesses the impact of treatments for tuberculosis, cancer and human immunodeficiency virus (the latter including highly active antiretroviral therapy) on ototoxic hearing loss. The paper also discusses obstacles to audiological monitoring for ototoxicity in the developing world, and the potential of audiology screening using applications for mobile devices.
A false aneurysm
Authors: Mitchell D , Repanos C , Coman W B
Published: March 2012

Objective:

We report a case of a remaining hemi-thyroid following laryngectomy, which was misinterpreted as a pseudoaneurysm.

Methods:

Case report and comment on this understandable error which is easily avoidable.

Results:

A 59-year-old man had undergone salvage laryngectomy for recurrent squamous cell carcinoma of the larynx, which had previously been treated with radiotherapy. Three months after his laryngectomy, he presented with a sore neck and subcutaneous collections. Computed tomography revealed a unilateral mass with high signal contrast uptake anterior to the left common carotid artery, which was thought initially to be a carotid pseudoaneurysm. Further investigation, including ultrasonography and a review by the senior head and neck radiologist, demonstrated that this mass was actually the remnant hemi-thyroid preserved at laryngectomy (which is often misshapen compared with a normal hemi-thyroid). The collections were found to be recurrent tumour, and unnecessary further interventions were avoided.

Conclusion:

Ultrasonography easily distinguishes between a thyroid remnant and a pseudoaneurysm. Furthermore, the opinion of an experienced head and neck radiologist may be vital when interpreting complex post-surgical head and neck radiology.
UV pulse trains by α-BBO crystal stacking for the production of THz-rap-rate electron bunches
Authors: YAN LI-XIN , HUA JIAN-FEI , DU YING-CHAO , HUANG YUAN-FANG , YOU YAN , WANG DAN , HUANG WEN-HUI , TANG CHUAN-XIANG
Published: March 2012

Ultrashort electron bunch trains can be used for plasma wake field acceleration (PWFA) to overcome the limit of transformer ratio of a single electron bunch, or high-power terahertz (Thz) radiation production by various radiation mechanisms. Basic facility for high-power THz radiation development based on ultrashort electron beam has been set up at accelerator lab of TUB. Using birefringent crystal serials, ultraviolet (UV) pulse shaping for photocathode radio frequency gun to produce THz-repetition-rate pulse train was realized. Driven by such pulses, ultrashort electron bunch train with picosecond (ps) spacing was obtained for THz production. Measurement of the stacked UV pulse trains was done by difference frequency generation (DFG), and the measured group velocity mismatch of α-BBO crystal at 266.7-nm wavelength was 0.8 ps/mm. This method may also be applied to form ramped electron bunch trains for PWFA.
Relationship between rainfall, pink shrimp harvest (Farfantepenaeus paulensis) and adult stock, associated with El Niño and La Niña phenomena in Patos Lagoon, southern Brazil
Authors: Pereira Natalia , D'Incao Fernando
Published: March 2012

The pink shrimp (Farfantepenaeus paulensis) is a very important fishery resource in southern/south Brazil. A great part of the total capture at these regions results from the artisanal fishery activity in Patos Lagoon estuary. The study of this species has importance because it is the main source of income for the communities of artisanal fisheries. This paper relates the climatic effects and the size of the species' adult stock with the harvest of pink shrimp in the estuary, in order to determine the influence of these variables on annual landings (t).
Contrasting relationships between pyloric caecum and gonad growth in the starfish Asterias rubens: combined field and experimental approaches
Authors: Joly-Turquin Guillemette , Dubois Philippe , Leyzour Sandra , Pernet Philippe , De Ridder Fjo , Pintelon Rik , Guillou Monique
Published: March 2012

The common starfish, Asterias rubens, occurs in fluctuating environments in the North Atlantic. To better understand energy allocation dynamics, we recorded gonad, body wall, and pyloric caeca (storage organ) indices between 2000 and 2004 from three different habitats. We applied a Fourier transform to the data to evaluate and compare the seasonal variation in these indices. Specific effects of emersion and salinity variation were examined in two laboratory studies. Differences in energy allocation were found between sites and temporally within sites. Food availability appeared to be the most important factor controlling allocation dynamics while fluctuating salinity and/or emersion had a significant but smaller impact. Only severe food shortage reduced reproductive investment indicating a preferential energy allocation to gonads. This study is the first to encompass a broad range of populations over several reproduction cycles and emphasizes the ability of A. rubens to adapt to a fluctuating environment.
Exposure, probable PTSD and lower respiratory illness among World Trade Center rescue, recovery and clean-up workers
Authors: Luft B. J. , Schechter C. , Kotov R. , Broihier J. , Reissman D. , Guerrera K. , Udasin I. , Moline J. , Harrison D. , Friedman-Jimenez G. , Pietrzak R. H. , Southwick S. M. , Bromet E. J.
Published: March 2012

Background

Thousands of rescue and recovery workers descended on the World Trade Center (WTC) in the wake of the terrorist attack of September 11, 2001 (9/11). Recent studies show that respiratory illness and post-traumatic stress disorder (PTSD) are the hallmark health problems, but relationships between them are poorly understood. The current study examined this link and evaluated contributions of WTC exposures.

Method

Participants were 8508 police and 12 333 non-traditional responders examined at the WTC Medical Monitoring and Treatment Program (WTC-MMTP), a clinic network in the New York area established by the National Institute for Occupational Safety and Health (NIOSH). We used structural equation modeling (SEM) to explore patterns of association among exposures, other risk factors, probable WTC-related PTSD [based on the PTSD Checklist (PCL)], physician-assessed respiratory symptoms arising after 9/11 and present at examination, and abnormal pulmonary functioning defined by low forced vital capacity (FVC).

Results

Fewer police than non-traditional responders had probable PTSD (5.9%v. 23.0%) and respiratory symptoms (22.5%v. 28.4%), whereas pulmonary function was similar. PTSD and respiratory symptoms were moderately correlated (r=0.28 for police and 0.27 for non-traditional responders). Exposure was more strongly associated with respiratory symptoms than with PTSD or lung function. The SEM model that best fit the data in both groups suggested that PTSD statistically mediated the association of exposure with respiratory symptoms.

Conclusions

Although longitudinal data are needed to confirm the mediation hypothesis, the link between PTSD and respiratory symptoms is noteworthy and calls for further investigation. The findings also support the value of integrated medical and psychiatric treatment for disaster responders.