bluuebunny/crossref_metadata_2025 huggingface dataset:
Charging in scanning electron microscopy “from inside and outside”
Authors: Cazaux Jacques
Published: June 2010

This paper is an attempt to analyse most of the complicated mechanisms involved in charging and discharging of insulators investigated by scanning electron microscopy (SEM). Fundamental concepts on the secondary electron emission (SEE) yield from insulators combined with electrostatics arguments permit to reconsider, first, the widespread opinion following which charging is minimized when the incident beam energy E0 is chosen to be equal to the critical energy E°2, where the nominal total yield δ°+η°=1. For bare insulators submitted to a defocused irradiation, it is suggested here that the critical energy under permanent irradiation EC2 corresponds to a range of primary electrons, R, and nearly equals the maximum escape depth of the secondary electrons, r. This suggestion is supported by a comparison between published data of the SEE yield δ° of insulators (short pulse experiments) and experimental results obtained from a permanent irradiation for EC2. New SEE effects are also predicted at the early beginning of irradiation when finely focused probes are used. Practical considerations are also developed, with specific attention given to the role of a contamination layer where a negative charging may occur at any beam energy. The role of the various time constants involved in charging and discharging is also investigated, with special attention given to the dielectric time constant, which explains the dose rate‐dependent effects on the effective landing energy in the steady state. Numerical applications permit to give orders of magnitude of various effects, and several other practical consequences are deduced and illustrated. Some new mechanisms for the contrast reversal during irradiation or with the change of the primary electron (PE) energy are also suggested.
Atomic force microscopy imaging of retroviruses: Human immunodeficiency virus and murine leukemia virus
Authors: Kuznetsov Yu. G. , Low A. , Fan H. , McPherson A. , Victoria J. G. , Robinson W. E.
Published: June 2010

Retroviruses are membrane‐enveloped, RNA‐containing viruses that produce a wide range of threatening diseases in higher animals. Among these are human immunodeficiency virus (HIV), which produces acquired immune deficiency syndrome (AIDS) in humans, and murine leukemia virus (MuLV), which produces leukemias in rodents. We have obtained the first atomic force microscopy (AFM) images of these two retroviruses, both isolated from culture media and emerging from infected cell surfaces. The HIV virions are 127 nm diameter on average, and those of MuLV are 145 nm, although there are wide distributions about the means. The AFM images show the arrangement of the envelope protein, responsible for host cell entry, on the surfaces of both virions. Disruption of the viruses using detergents or physical means allowed us to visualize interior structures, including the outer shells of both MuLVand HIV, the cores of MuLV, and the nucleic acid of HIV complexed with core proteins. Using immunolabeling techniques borrowed from electron microscopy, we were able to demonstrate the binding of gold‐labeled antibodies directed against the envelope protein of MuLV. The AFM images are revealing, not only in terms of surface topology, but in terms of interior features as well, and they reveal the eccentricities and uniqueness of individual virus particles rather than yielding the average member of the population. Further application of AFM to viruses associated with other pathologies may ultimately have a significant impact on the diagnosis and treatment of virus‐promoted diseases.
Mechanical scanning of the specimen in the scanning electron microscope
Authors: Oho Eisaku , Miyamoto Makoto
Published: June 2010

A scanning electron microscope (SEM) system equipped with a motor drive specimen stage fully controlled with a personal computer (PC) has been utilized for obtaining ultralow magnification SEM images. This modern motor drive stage works as a mechanical scanning device. To produce ultra‐low magnification SEM images, we use a successful combination of the mechanical scanning, electronic scanning, and digital image processing techniques. This new method is extremely labor and time saving for ultra‐low magnification and wide‐area observation. The option of ultra‐low magnification observation (while maintaining the original SEM functions and performance) is important during a scanning electron microscopy session.
Improved depth of field in the scanning electron microscope derived from through‐focus image stacks
Authors: Boyde Alan
Published: June 2010

The depth of field limit in the scanning electron microscope (SEM) can be overcome by recording stacks of through‐focus images (as in conventional and confocal optical microscopy) which are postprocessed to generate an all‐in‐focus image. Images are recorded under constant electron optical conditions by mechanical Z‐axis movement of the sample. This gives rise to a change in magnification through the stack due to the perspective projection of the SEM image. Calculation of the necessary scaling as well as the derivation of best focus information at every patch in the image‐and a contour map function derived from the selected patch depths‐are incorporated in a new software package (Auto‐Montage Pro). The utility of these procedures is demonstrated with examples from the study of human osteoporotic bone, where results show uncoupling of resorption and formation. The procedure can be combined with pseudo‐colour coding for the direction of apparent illumination when using backscattered electron (BSE) detectors in contrasting positions.
Image signal‐to‐noise ratio and noise variance estimation using autoregressive model
Authors: Kamel Nidal S. , Sim K. S.
Published: June 2010

During the last three decades, several techniques have been proposed for signal‐to‐noise ratio (SNR) and noise variance estimation in images, with different degrees of success. Recently, a novel technique based on the statistical autoregressive model (AR) was developed and proposed as a solution to SNR estimation in scanning electron microscope (SEM) image. In this paper, the efficiency of the developed technique with different imaging systems is proven and presented as an optimum solution to image noise variance and SNR estimation problems. Simulation results are carried out with images like Lena, remote sensing, and SEM. The two image parameters, SNR and noise variance, are estimated using different techniques and are compared with the AR‐based estimator.
A spectroscopic scanning electron microscope design
Authors: Khursheed Anjam , Osterberg Mans
Published: June 2010

This paper describes a proposal to improve the design of scanning electron microscopes (SEMs). The design is based upon using an SEM column similar to the conventional one, magnetic sector plates and a mixed field immersion objective lens. The optical axis of the SEM column lies in the horizontal direction and the primary beam is turned through 90 degrees before it reaches the specimen. This arrangement allows for the efficient collection, detection and spectral analysis of the scattered electrons on a hemispherical surface that is located well away from the rest of the SEM column. The proposed SEM design can also be easily extended to incorporate time multiplexed columns and multi‐column arrays.
2.2 μm axial resolution optical coherence tomography based on a 400 nm‐bandwidth superluminescent diode
Authors: Chan Ming‐Che , Su Yi‐Shin , Lin Ching‐Fuh , Sun Chi‐Kuang
Published: June 2010

We demonstrate 2.2 μm axial resolution optical coherence tomography (OCT) in 1.1‐1.7 μm wavelength regime by using a nonidentical multiple‐quantum‐well (MQW) superluminescent diode (SLD) with record‐bandwidth emission. The compact, low‐cost, and reliable light source with extreme broadband emission demonstrates significant potentials for spectroscopic and commercial OCT applications requiring ultrahigh spatial resolution.
Quantitative analysis of EcoR1 methylase‐DNA complex by atomic force microscopy
Authors: Zhu Yi , Zeng Hu , Gao Xiang , Lu Zuhong
Published: June 2010

The EcoR1 methylase specifically recognize 5′–GA* ATTC‐3′in DNA duplex. We directly applied atomic force microscopy (AFM) to investigate linear pBR322‐EcoR1 methylase complexes and quantitatively analyzed the bend angles of linear pBR322‐EcoR1 methylase complexes and the bound protein widths. In this study, we made a novel observation that DNA‐EcoR1 methylase complexes exhibited two populations of conformation at recognition site: DNA bent an acute angle at the recognition site in the presence of one EcoR1 methylase monomeric molecule, while DNA bent an unacute angle at the recognition site and the complementary site on duplex DNAs in the presence of EcoR1 methylase dimer. The data indicated that the unacute angle state was the result of unique interactions between EcoR1 methylase and the recognition site and the complementary site on duplex DNAs, and suggested that the acute angle conformation could be an intermediate in the formation of the unacute angle state. Our works provide a detail insight into the DNA structural variations involved in EcoR1 methylase‐binding processes and demonstrate further the versatility of AFM as an imaging technique for studying the interaction between large DNA fragment and protein.
Analysis of point fabrication model for near‐field photolithography with experimental study
Authors: Lin Zone‐Ching , Yang Ching‐Been
Published: June 2010

For the Gaussian beam, the power density distribution of the aluminum‐coated optical tapered fiber probe is discussed and a theoretical fixed‐point fabrication model for near‐field photolithography is established. The energy density theorem is used to explore the surface exposure of photoresist, which is divided into multiple grids to evaluate the changes in the concentration of photoactive compounds at specific nodes of the interior layer. The full width at half maximum (FWHM) and the contour of the photolithograph following development are then calculated. The fixed‐point lithographic experiment and aperture verification of the optic fiber probe are performed to confirm the reliability of the present model, and Dill A, B, C parameters are first measured in this article. According to the experimental results, a better image of the probe aperture can be achieved by increasing the conductivity of the measured articles and reducing the electric charges during the image taken by field‐emission scanning electron microscope. The FWHM measured is 166.6 nm, while the measured average probe aperture size is 317.4 nm and the FWHM simulated by the proposed model is 151.3 nm. The error between experiment and simulation is <−9.2%. It is thus concluded that the proposed theoretical model is reasonable and acceptable.
Aberration model of a multibeam scanning microscope for electron beam‐induced deposition
Authors: van Bruggen M. J. , van Someren B. , Kruit P.
Published: June 2010

A multibeam electron beam‐induced deposition (EBID) system is presented, which aims at the fabrication of sub‐10 nm structures with EBID. This system consists of a multibeam source (MBS) module, delivering 100 virtual sources and a standard scanning electron microscope (SEM) column to image the 100 sources onto a wafer. In the proposed concept, beamlets are traveling off‐axis through the projection lenses, introducing off‐axis aberrations. An analytical description of the projection lens aberrations is derived and the system is optimized by tuning a field lens, which only affects the direction of the beamlets as they enter the projection system. It is found that this lens must be excited such that all beamlets go through the center of the last projection lens. This is an important design rule for the total system.
Revealing the Role of Anchoring Groups in the Electrical Conduction Through Single‐Molecule Junctions
Authors: Zotti Linda A. , Kirchner Thomas , Cuevas Juan‐Carlos , Pauly Fabian , Huhn Thomas , Scheer Elke , Erbe Artur
Published: June 2010

A combined experimental and theoretical study is presented revealing the influence of metal–molecule coupling on electronic transport through single‐molecule junctions. Transport experiments through tolane molecules attached to gold electrodes via thiol, nitro, and cyano anchoring groups are performed. By fitting the experimental current–voltage characteristics to a single‐level tunneling model, we extract both the position of the molecular orbital closest to the Fermi energy and the strength of the metal–molecule coupling. The values found for these parameters are rationalized with the help of density‐functional‐theory‐based transport calculations. In particular, these calculations show that the anchoring groups determine the junction conductance by controlling not only the strength of the coupling to the metal but also the position of the relevant molecular energy levels.
Out‐of‐Plane Magnetic Patterning Based on Indentation‐Induced Nanocrystallization of a Metallic Glass
Authors: Sort Jordi , Bonavina Luiz Fernando , Varea Aïda , Souza Carlos , Botta Walter J. , Kiminami Claudio S. , Bolfarini Claudemiro , Suriñach Santiago , Baró Maria Dolors , Nogués Josep
Published: June 2010

Periodic arrays of micrometer‐sized ferromagnetic structures with perpendicular magnetic anisotropy are prepared by nanoindentation at the surface of a Fe67.7B20Cr12Nb0.3 glassy ribbon initially showing in‐plane magnetic anisotropy. The indented regions exhibit enhanced coercivity and saturation magnetization with respect to the surrounding nondeformed matrix. These effects are due to a mechanically driven selective nanocrystallization of the metallic glass, induced by nanoindentation, even without the need for thermal annealing. In addition, while the amorphous matrix becomes paramagnetic above 325 K, the crystallized regions (consisting of α‐Fe) remain ferromagnetic upon heating to high temperatures. The local change in the magnetic anisotropy direction is ascribed to a certain degree of crystallographic texture, together with the inverse magnetostriction effect caused by the compressive indentation stresses.
Mandatory fortification of the food supply with cobalamin: an idea whose time has not yet come
Authors: Carmel Ralph
Published: June 2010

The success of folic acid fortification has generated consideration of similar fortification with cobalamin for its own sake but more so to mitigate possible neurologic risks from increased folate intake by cobalamin‐deficient persons. However, the folate model itself, the success of which was predicted by successful clinical trials and the known favorable facts of high folic acid bioavailability and the infrequency of folate malabsorption, may not apply to cobalamin fortification. Cobalamin bioavailability is more restricted than folic acid and is unfortunately poorest in persons deficient in cobalamin. Moreover, clinical trials to demonstrate actual health benefits of relevant oral doses have not yet been done in persons with mild subclinical deficiency, who are the only practical targets of cobalamin fortification because >94% of persons with clinically overt cobalamin deficiency have severe malabsorption and therefore cannot respond to normal fortification doses. However, it is only in the severely malabsorptive disorders, such as pernicious anemia, not subclinical deficiency, that neurologic deterioration following folic acid therapy has been described to date. It is still unknown whether mild deficiency states, which usually arise from normal absorption or only food‐bound cobalamin malabsorption, have real health consequences or how often they progress to overt clinical cobalamin deficiency. Reports of cognitive or other risks in the common subclinical deficiency state, although worrisome, have been inconsistent. Moreover, their observational nature proved neither causative connections nor documented health benefits. Extensive work, especially randomized clinical trials, must be done before mandatory dietary intervention on a national scale can be justified.
Flaking as a Pretreatment for Enzyme‐Assisted Aqueous Extraction Processing of Soybeans
Authors: de Moura J. M. L. N. , de Almeida N. M. , Jung S. , Johnson L. A.
Published: June 2010

Soybean moisture content (7.2–12.8%) and conditioning temperature (51–79 °C) during flaking were evaluated to determine their effects on oil and protein extraction and oil distribution among fractions produced in enzyme‐assisted aqueous extraction processing (EAEP). Extractions were performed by using two‐stage countercurrent EAEP at a 1:6 solids‐to‐liquid ratio with 0.5% protease (wt/g extruded flakes) at pH 9.0 and 50 °C for 1 h. Oil extraction improved when using soybeans with moisture contents ranging from 8.0 to 12.0% for flaking but was not affected by conditioning temperature. Oil extraction was reduced when moving away from 10% moisture with the lowest values at 7.2 and 12.8% moisture. Free oil extraction increased as soybean moisture content increased from 7.2 to 12.8% although total oil extraction was reduced at 12.8% moisture. Higher (79 °C) and lower conditioning temperatures (51 °C) improved free oil extraction and reduced cream emulsion formation. Skim oil content was not significantly affected by soybean moisture content and the conditioning temperature, although an undesirable high oil content in the skim was observed at 8% moisture and at 55 °C. The cream with a high oil yield was easily demulsified compared with cream containing a low oil yield (95 vs. 76.5% de‐emulsification). Due to differences in cream stability, similar oil recoveries (78–80%) were obtained for treatments yielding creams with either low or high oil yields. Mean protein extraction of 95% was achieved for all treatments and was not significantly affected by soybean moisture content at flaking or conditioning temperature.
Kinetic and thermodynamic properties of two barley thioredoxin h isozymes, HvTrxh1 and HvTrxh2
Authors: Maeda Kenji , Hägglund Per , Björnberg Olof , Winther Jakob R. , Svensson Birte
Published: June 2010

Barley thioredoxin h isozymes 1 (HvTrxh1) and barley thioredoxin h isozymes 2 (HvTrxh2) show distinct spatiotemporal distribution in germinating seeds. Using a novel approach involving measurement of bidirectional electron transfer rates between Escherichia coli thioredoxin, which exhibits redox‐dependent fluorescence, and the barley isozymes, reaction kinetics and thermodynamic properties were readily determined. The reaction constants were ∼60% higher for HvTrxh1 than HvTrxh2, while their redox potentials were very similar. The primary nucleophile, CysN, of the active site Trp‐CysN‐Gly‐Pro‐CysC motif has an apparent pK
a of 7.6 in both isozymes, as found by iodoacetamide titration, but showed ∼70% higher reactivity in HvTrxh1, suggesting significant functional difference between the isozymes.
Preliminary NSQIP results: A tool for quality improvement
Authors: Stachler Robert J. , Yaremchuk Kathleen , Ritz Jennifer
Published: June 2010

Objective

To utilize National Surgical Quality Improvement Program (NSQIP) data to evaluate patient outcomes in otolaryngology–head and neck surgery.

Study Design

Retrospective medical chart abstraction of patients undergoing major surgical procedures in the inpatient and outpatient setting.

Setting

Academic/teaching hospitals with more than 500 beds.

Subjects and Methods

The American College of Surgeons NSQIP collects data on 135 variables including preoperative risk factors, intraoperative variables, and 30‐day‐postoperative mortality and morbidity outcomes for patients undergoing major surgical procedures in the inpatient and outpatient setting. As of August 2008, there are currently 47 hospitals submitting data for otolaryngology–head and neck surgery.

Results

Opportunities for improvement were identified in respiratory, wound, and venothromboembolic (VTE) occurrences. Implementation of a standardized VTE and perioperative protocol resulted in a decreased length of stay and observed‐to‐expected (O/E) morbidity and mortality for all surgical services.

Conclusion

NSQIP reports form the basis for quality improvement with targeted interventions in areas of concern that result in changes in patient care processes. The reports are composed of outcomes‐based, risk‐adjusted data that are submitted by participating hospitals and have recently included data for otolaryngology–head and neck surgery. Actions taken based on NSQIP data demonstrate improvements in patient morbidity and mortality, decreased length of stay, and decreased hospital costs. In a time of increased scrutiny of health care costs and outcomes, NSQIP is an important tool for surgeons to improve quality and decrease costs.
Polymeric micelle nanoparticles for photodynamic treatment of head and neck cancer cells
Authors: Cohen Evan M. , Ding Huiying , Kessinger Chase W. , Khemtong Chalermchai , Gao Jinming , Sumer Baran D.
Published: June 2010

Objective

To encapsulate 5,10,15,20‐tetrakis(meso‐hydroxyphenyl)porphyrin (mTHPP), a photosensitizer, into polymeric micelles; characterize the micelles; and test in vitro photodynamic therapy efficacy against human head and neck cancer cells.

Study Design

A nanoparticle design, fabrication, and in vitro testing study.

Setting

Polymer chemistry laboratory.

Subjects and Methods

Micelles encapsulating mTHPP were produced, and micellar size was measured. Ultraviolet visible spectra and fluorescence spectroscopy were used to characterize the mTHPP‐loaded micelles. In vitro cell culture using HSC‐3 and HN‐5 cancer cells was performed to test the photodynamic therapy efficacy of the micelles using confocal microscopy and method of transcriptional and translational (MTT) assay.

Results

mTHPP was encapsulated with high loading efficiency (> 85%) and density (up to 17%) into micelles. Micelle size was 30.6 ± 3.3 nm by transmission electron microscopy and 30.8 ± 0.6 nm by dynamic light scattering. The absorption maximum for each sample was 418 nm, and fluorescent spectroscopy revealed quenching with maximal fluorescence at five percent loading. Significant cytotoxicity was observed with confocal microscopy when HSC‐3 cells were treated with 10 percent mTHPP micelles, with 100 percent cytotoxicity within the zone of laser light exposure at 420 nm. Phototoxicity and dark toxicity against HSC‐3 and HN‐5 cells measured using the MTT assay with five and 10 percent loaded mTHPP micelles demonstrated greater than 90 percent cytotoxicity with photodynamic therapy and less than 10 percent dark toxicity at a micelle concentration of 25 μg/mL for both cell lines.

Conclusion

Micelles were able to encapsulate and solubilize mTHPP at high loading densities with uniform size distribution. These micelles exhibit fluorescence and photodynamic therapy mediated cytotoxicity against head and neck cancer cells in vitro.
Patients with severe obstructive sleep apnea syndrome and elevated high‐sensitivity C‐reactive protein need priority treatment
Authors: Lee Li‐Ang , Chen Ning‐Hung , Huang Chung‐Guei , Lin Shih‐Wei , Fang Tuan‐Jen , Li Hsueh‐Yu
Published: June 2010

Objective

To evaluate the clinical factors predicting the significantly elevated high‐sensitivity C‐reactive protein (hs‐CRP) concentrations, defined herein as hs‐CRP ≥ 3 mg/L, in adult males with untreated obstructive sleep apnea syndrome (OSAS).

Study Design

Cross‐sectional study.

Setting

Tertiary referral center.

Subjects and Methods

Sixty‐five consecutive male patients with newly diagnosed OSAS were enrolled to receive complete medical history review, physical examination, in‐laboratory overnight polysomnography, and hs‐CRP test. The patients had no current or history of cardiovascular disease. The patients had a mean age of 38.2 ± 9.9 years, body mass index (BMI) of 27.4 ± 3.5 kg/m2, and Epworth Sleepiness Scale (ESS) of 11.3 ± 4.6. The serum levels of hs‐CRP were assessed using peripheral venous blood samples.

Results

Twenty‐three percent of the overall patients had significantly elevated serum levels of hs‐CRP. The increase of hs‐CRP correlated fairly with BMI, apnea‐hypopnea index (AHI), tonsil size, and ESS (r = 0.450, 0.398, 0.393, and 0.300, respectively; all P ≤ 0.05) after adjustment for conventional coronary heart disease risk factors. However, only the AHI could predict for significantly elevated hs‐CRP after stepwise multiple linear regression (R 2 = 0.251, P < 0.001).

Conclusion

Patients in this study with hs‐CRP ≥ 3 mg/L were more prevalent in the severe OSAS group. This observation suggests that the severe OSAS patients need to have their cardiovascular statuses evaluated by use of an hs‐CRP screening test.
COMODULES AND CONTRAMODULES
Authors: WISBAUER ROBERT
Published: June 2010

Algebras A and coalgebras C over a commutative ring R are defined by properties of the (endo)functors A ⊗R – and C ⊗R – on the category of R-modules R. Generalising these notions, monads and comonads were introduced on arbitrary categories, and it turned out that some of their basic relations do not depend on the specific properties of the tensor product. In particular, the adjoint of any comonad is a monad (and vice versa), and hence, for any coalgebra C, HomR(C, –), the right adjoint of C ⊗R –, is a monad on R. The modules for the monad HomR(C, –) were called contramodules by Eilenberg–Moore and the purpose of this talk is to outline the related constructions and explain the relationship between C-comodules and C-contramodules. The results presented grew out from cooperation with G. Böhm, T. Brzeziński and B. Mesablishvili.
RINGS OVER WHICH CYCLICS ARE DIRECT SUMS OF PROJECTIVE AND CS OR NOETHERIAN
Authors: HOLSTON C. J. , JAIN S. K. , LEROY A.
Published: June 2010

R is called a right WV-ring if each simple right R-module is injective relative to proper cyclics. If R is a right WV-ring, then R is right uniform or a right V-ring. It is shown that a right WV-ring R is right noetherian if and only if each right cyclic module is a direct sum of a projective module and a CS (complements are summands, a.k.a. ‘extending modules’) or noetherian module. For a finitely generated module M with projective socle over a V-ring R such that every subfactor of M is a direct sum of a projective module and a CS or noetherian module, we show M = X ⊕ T, where X is semisimple and T is noetherian with zero socle. In the case where M = R, we get R = S ⊕ T, where S is a semisimple artinian ring and T is a direct sum of right noetherian simple rings with zero socle. In addition, if R is a von Neumann regular ring, then it is semisimple artinian.
GOLDIE-SUPPLEMENTED MODULES
Authors: BIRKENMEIER G. F. , MUTLU F. TAKIL , NEBİYEV C. , SOKMEZ N. , TERCAN A.
Published: June 2010

Motivated by a relation on submodules of a module used by both A. W. Goldie and P. F. Smith, we say submodules X, Y of M are β* equivalent, Xβ*Y, if and only if $\(\frac{X+Y}{X}\)$ is small in $\(\frac{M}{X}\)$ and $\(\frac{X+Y}{Y}\)$ is small in $\(\frac{M}{Y}\)$. We show that the β* relation is an equivalence relation and has good behaviour with respect to addition of submodules, homomorphisms and supplements. We apply these results to introduce the class of -supplemented modules and to investigate this class and the class of H-supplemented modules. These classes are located among various well-known classes of modules related to the class of lifting modules. Moreover these classes are used to explore an open question of S. H. Mohamed and B. J. Mueller. Examples are provided to illustrate and delimit the theory.
MONOMORPHISMS AND KERNELS IN THE CATEGORY OF FIRM MODULES
Authors: GONZÁLEZ-FÉREZ JUAN , MARÍN LEANDRO
Published: June 2010

In this paper we consider for a non-unital ring R, the category of firm R-modules for a non-unital ring R, i.e. the modules M such that the canonical morphism μM : R ⊗RM → M given by r ⊗ m ↦ rm is an isomorphism. This category is a natural generalization of the usual category of unitary modules for a ring with identity and shares many properties with it. The only difference is that monomorphisms are not always kernels. It has been proved recently that this category is not Abelian in general by providing an example of a monomorphism that is not a kernel in a particular case. In this paper we study the lattices of monomorphisms and kernels, proving that the lattice of monomorphisms is a modular lattice and that the category of firm modules is Abelian if and only if the composition of two kernels is a kernel.
PROPERTIES OF INJECTIVE HULLS OF A RING HAVING A COMPATIBLE RING STRUCTURE
Authors: OSOFSKY BARBARA L. , PARK JAE KEOL , RIZVI S. TARIQ
Published: June 2010

If the injective hull E = E(RR) of a ring R is a rational extension of RR, then E has a unique structure as a ring whose multiplication is compatible with R-module multiplication. We give some known examples where such a compatible ring structure exists when E is a not a rational extension of RR, and other examples where such a compatible ring structure on E cannot exist. With insights gleaned from these examples, we study compatible ring structures on E, especially in the case when ER, and hence RR ⊆ ER, has finite length. We show that for RR and ER of finite length, if ER has a ring structure compatible with R-module multiplication, then E is a quasi-Frobenius ring under that ring structure and any two compatible ring structures on E have left regular representations conjugate in Λ = EndR(ER), so the ring structure is unique up to isomorphism. We also show that if ER is of finite length, then ER has a ring structure compatible with its R-module structure and this ring structure is unique as a set of left multiplications if and only if ER is a rational extension of RR.
POOR MODULES: THE OPPOSITE OF INJECTIVITY
Authors: ALAHMADI ADEL N. , ALKAN MUSTAFA , LÓPEZ-PERMOUTH SERGIO
Published: June 2010

A module M is called poor whenever it is N-injective, then the module N is semisimple. In this paper the properties of poor modules are investigated and are used to characterize various families of rings.
INJECTIVE MODULES OVER DOWN-UP ALGEBRAS
Authors: CARVALHO PAULA A. A. B. , LOMP CHRISTIAN , PUSAT-YILMAZ DILEK
Published: June 2010

The purpose of this paper is to study finiteness conditions on injective hulls of simple modules over Noetherian down-up algebras. We will show that the Noetherian down-up algebras A(α, β, γ) which are fully bounded are precisely those which are module-finite over a central subalgebra. We show that injective hulls of simple A(α, β, γ)-modules are locally Artinian provided the roots of X2 − αX − β are distinct roots of unity or both equal to 1.
LINEAR PROPERTIES OF GOLDIE DIMENSION OF MODULES AND MODULAR LATTICES
Authors: PUCZYŁOWSKI EDMUND R.
Published: June 2010

We survey some old and recent results concerning the Goldie dimension of modules and modular lattices and its properties which are counterparts of properties of the dimension of linear spaces.
GOLDIE DIMENSION, DUAL KRULL DIMENSION AND SUBDIRECT IRREDUCIBILITY
Authors: ALBU TOMA
Published: June 2010

In this survey paper we present some results relating the Goldie dimension, dual Krull dimension and subdirect irreducibility in modules, torsion theories, Grothendieck categories and lattices. Our interest in studying this topic is rooted in a nice module theoretical result of Carl Faith [Commun. Algebra27 (1999), 1807–1810], characterizing Noetherian modules M by means of the finiteness of the Goldie dimension of all its quotient modules and the ACC on its subdirectly irreducible submodules. Thus, we extend his result in a dual Krull dimension setting and consider its dualization, not only in modules, but also in upper continuous modular lattices, with applications to torsion theories and Grothendieck categories.
Direct numerical simulation of transonic shock/boundary layer interaction under conditions of incipient separation
Authors: PIROZZOLI SERGIO , BERNARDINI MATTEO , GRASSO FRANCESCO
Published: June 2010

The interaction of a normal shock wave with a turbulent boundary layer developing over a flat plate at free-stream Mach numberM∞= 1.3 and Reynolds numberReθ≈ 1200 (based on the momentum thickness of the upstream boundary layer) is analysed by means of direct numerical simulation of the compressible Navier–Stokes equations. The computational methodology is based on a hybrid linear/weighted essentially non-oscillatory conservative finite-difference approach, whereby the switch is controlled by the local regularity of the solution, so as to minimize numerical dissipation. As found in experiments, the mean flow pattern consists of an upstream fan of compression waves associated with the thickening of the boundary layer, and the supersonic region is terminated by a nearly normal shock, with substantial bending of the interacting shock. At the selected conditions the flow does not exhibit separation in the mean. However, the interaction region is characterized by ‘intermittent transitory detachment’ with scattered spots of instantaneous flow reversal throughout the interaction zone, and by the formation of a turbulent mixing layer, with associated unsteady release of vortical structures. As found in supersonic impinging shock interactions, we observe a different amplification of the longitudinal Reynolds stress component with respect to the others. Indeed, the effect of the adverse pressure gradient is to reduce the mean shear, with subsequent suppression of the near-wall streaks, and isotropization of turbulence. The recovery of the boundary layer past the interaction zone follows a quasi-equilibrium process, characterized by a self-similar distribution of the mean flow properties.
Lymph node central necrosis on computed tomography as predictor of extracapsular spread in metastatic head and neck squamous cell carcinoma: pilot study
Authors: Zoumalan R A , Kleinberger A J , Morris L G T , Ranade A , Yee H , DeLacure M D , Myssiorek D
Published: June 2010

Objective:

This study aimed (1) to investigate the relationship between the presence of lymph node central necrosis, viewed on pre-operative computed tomography imaging, and the occurrence of histopathologically determined metastatic lymph node extracapsular spread and (2) to determine whether a larger scale study would be valuable.

Materials and methods:

Pre-operative computed tomography scans, surgical records and post-operative histopathological analysis results were reviewed for 19 consecutive neck dissections performed in 17 patients with head and neck squamous cell carcinoma.

Results:

A total of 20/26 (77 per cent) lymph nodes with central necrosis had extracapsular spread on histopathological analysis. Twenty of 21 (95 per cent) lymph nodes with extracapsular spread had central necrosis on pre-operative computed tomography. Thirty-four of 40 (85 per cent) lymph nodes without extracapsular spread had no evidence of central necrosis on computed tomography. Only three of 12 (25 per cent) patients with lymph node central necrosis identified on pre-operative computed tomography were found to have actual necrosis on final histopathological analysis.

Conclusions:

Lymph node central necrosis viewed on pre-operative computed tomography scans is a useful indicator of metastatic lymph node extracapsular spread, with a sensitivity of 95 per cent, a specificity of 85 per cent, a positive predictive value of 69 per cent and a negative predictive value of 98 per cent. Lymph node diameter is not a sensitive indicator of extracapsular spread.
Recurrent familial malignant carotid body tumour presenting with lymph node metastasis: case report, and review of diagnosis and management of familial carotid body tumours
Authors: Hall T C , Renwick P , Stafford N D
Published: June 2010

Objective:

We report the case of a recurrent familial malignant carotid body tumour presenting with metastasis to local ipsilateral lymph nodes; the rarity of both recurrence combined with nodal spread is emphasised in this article.

Method:

We present a case report, and a review of the world literature concerning the diagnosis and management of carotid body tumours in the familial setting.

Case report:

A woman with a family history of succinate dehydrogenase complex subunit B gene mutation presented with right vocal fold palsy. A causative carotid body tumour was excised. Fifteen years later, the patient developed a right-sided swelling in the jugulo-digastric region, together with shooting pains towards her right ear. Imaging revealed right posterior triangle lymphadenopathy. Fine needle aspiration cytology of the node was equivocal. Computed tomography of her neck revealed, in addition, a mass within the right side of the larynx. Excision biopsy of the lymph node demonstrated metastatic paraganglioma. A carotid angiogram revealed a right-sided carotid body tumour. This was embolised prior to neck exploration and excision of the carotid body tumour with en bloc resection of adjacent nodes. Histological analysis confirmed the presence of lymph nodes containing metastatic paraganglioma.

Conclusion:

This case report demonstrates the need for extra vigilance to enable early disease detection in the familial setting of carotid body tumour, in order to reduce the surgical morbidity associated with disease progression. In addition, our report highlights the atypical aspects of presentation in the familial setting, together with the difficulty and lack of standardisation regarding monitoring of the disease.
Fish farms as amphibian habitats: factors affecting amphibian species richness and community structure at carp ponds in Poland
Authors: KLOSKOWSKI JANUSZ
Published: June 2010

Open fish ponds are a potential consideration in the conservation of biodiversity, yet information on their suitability for breeding amphibians remains lacking. This study examined amphibian responses to attributes of pond habitats at common carp Cyprinus carpio farms in eastern Poland, focusing on features typical of traditional European cyprinid culture. Canonical correspondence analysis identified age of fish stocks, density of predatory Anisoptera and pond hydroperiod as the factors most strongly influencing amphibian community composition expressed in terms of larval abundance. Separation of fish age-cohorts into different growing ponds was decisive for differential occurrence patterns of individual amphibian taxa. The amphibian assemblage was significantly nested: ponds stocked with young-of-the-year fish supported relatively high numbers of amphibian taxa, including endangered species known to be vulnerable to fish, while ponds containing one- and two-year-old carp harboured only more common taxa. These results suggest that traditional carp pond culture characterized by a spatially discrete distribution of inter-annual cohorts includes habitats compatible with amphibian conservation. However, a flexible conservational approach is needed: ponds stocked with young fish produce secondary breeding habitats for amphibians, but presence of large-sized carp is associated with severe species loss.
Early trajectories of interparental conflict and externalizing problems as predictors of social competence in preadolescence
Authors: Kouros Chrystyna D. , Cummings E. Mark , Davies Patrick T.
Published: June 2010

Consistent with developmental cascade notions, the present study investigated (a) associations between trajectories of interparental conflict and early externalizing problems during childhood and (b) early trajectories of externalizing problems as a pathway by which interparental conflict impacts children's social competence in preadolescence. Participants were 235 children and their parents and teachers. Children were assessed annually for 3 years, beginning when they were in kindergarten. Parents provided reports of interparental conflict and child externalizing problems. Children's social competence (prosocial behavior, social problems) was assessed approximately 5 years later via parent and teacher reports. Results from parallel process models indicated that changes in interparental conflict were positively associated with changes in externalizing problems during childhood. Further, demonstrating pathways consistent with notions of developmental cascades, early trajectories of externalizing problems accounted for the longitudinal link between early trajectories of interparental conflict and children's social problems in preadolescence.
Transactional relations across contextual strain, parenting quality, and early childhood regulation and adaptation in a high-risk sample
Authors: Yates Tuppett M. , Obradović Jelena , Egeland Byron
Published: June 2010

This investigation examined transactional relations across contextual strain, parenting quality, and child adjustment in 209 mothers and children at 24, 42, and 72 months of age. Independent ratings of mothers' stressful life events, social support, and relationship quality provided an objective measure of maternal contextual strain. Observers evaluated parenting quality during parent–child interactions at each time point. Child regulatory functioning during laboratory tasks at 24 and 42 months was evaluated by independent observers based on both behavioral (e.g., noncompliance, distractibility) and emotional (e.g., frustration, anger) indices. At 72 months, teachers reported on children's externalizing behaviors, and children completed objective measures of academic achievement. Nested path analyses were used to evaluate increasingly complex models of influence, including transactional relations between child and parent, effects from contextual strain to parenting and child adaptation, and reciprocal effects from child and parent behavior to contextual strain. Over and above stability within each domain and cross-sectional cross-domain covariation, significant paths emerged from maternal contextual strain to subsequent child adjustment. Bidirectional relations between parenting and child adjustment were especially prominent among boys. These findings counter unidirectional models of parent-mediated contextual effects by highlighting the direct influences of contextual strain and parent–child transactions on early childhood behavioral and academic adjustment, respectively.
Competence and psychopathology: Cascade effects in the NICHD Study of Early Child Care and Youth Development
Authors: Burt Keith B. , Roisman Glenn I.
Published: June 2010

Existing longitudinal research on the interplay between externalizing problems, internalizing problems, and academic and social competence has documented “cascading” effects from early aggressive/disruptive behavior through impairments in competence, leading to symptoms of depression and anxiety. The primary aim of the current study was to replicate such work using the NICHD Study of Early Child Care and Youth Development while also extending the developmental window of investigation of cascades back into early childhood. Participating families (N= 1,160) completed questionnaire measures of externalizing, internalizing, and social competence (maternal report), as well as individual assessment of academic achievement, spanning five time points from age 54 months through age 15 years. A series of nested structural equation models tested predicted links across various domains of competence and psychopathology. Results were consistent with prior research, demonstrating cross-domain effects from early externalizing problems through effects on both academic and social competence into later internalizing problems. Effects held across gender and were largely unaffected by inclusion of socioeconomic status, early caregiving, and early cognitive ability as covariates in the model.
Cascading peer dynamics underlying the progression from problem behavior to violence in early to late adolescence
Authors: Dishion Thomas J. , Véronneau Marie-Hélène , Myers Michael W.
Published: June 2010

This study examined the peer dynamics linking early adolescent problem behavior, school marginalization, and low academic performance to multiple indices of late adolescent violence (arrests, parent report, and youth report) in an ethnically diverse sample of 998 males and females. A cascade model was proposed in which early adolescent risk factors assessed at age 11 to 12 predict gang involvement at age 13 to 14, which in turn, predicts deviancy training with friends at age 16 to 17, which then predicts violence by age 18 to 19. Each construct in the model was assessed with multiple measures and methods. Structural equation modeling revealed that the cascade model fit the data well, with problem behavior, school marginalization, and low academic performance significantly predicting gang involvement 2 years later. Gang involvement, in turn, predicted deviancy training with a friend, which predicted violence. The best fitting model included an indirect and direct path between early adolescent gang involvement and later violence. These findings suggest the need to carefully consider peer clustering into gangs in efforts to prevent individual and aggregate levels of violence, especially in youths who may be disengaged, marginalized, or academically unsuccessful in the public school context.
Child and Adolescent Suicides in Bosnia and Herzegovina Before and After the War (1992–1995)
Authors: Fajkic Almir , Lepara Orhan , Voracek Martin , Kapusta Nestor D. , Niederkrotenthaler Thomas , Amiri Leena , Sonneck Gernot , Dervic Kanita
Published: June 2010

Background: Evidence on youth suicides from Southeastern Europe is scarce. We are not aware of previous reports from Bosnia and Herzegovina, which experienced war from 1992 to 1995. Durkheim’s theory of suicide predicts decreased suicide rates in wartime and increased rates afterward. Aims: To compare child and adolescent suicides in Bosnia and Herzegovina before and after the war. Methods: Data on youth suicide for prewar (1986–90) and postwar (2002–06) periods were analyzed with respect to prevalence, sex and age differences, and suicide methods. Suicide data from 1991 through 2001 were not available. Results: Overall youth suicide rates were one-third lower in the postwar than in the prewar period. This effect was most pronounced for girls, whose postwar suicide rates almost halved, and for 15–19-year-old boys, whose rates decreased by about a one-fourth. Suicides increased among boys aged 14 or younger. Firearm suicides almost doubled proportionally and were the predominant postwar method, while the most common prewar method had been hanging. Conclusions: The findings from this study indicate the need for public education in Bosnia and Herzegovina on the role of firearm accessibility in youth suicide and for instructions on safe storage in households. Moreover, raising societal awareness about suicide risk factors and suicide prevention is needed.
Measurements of electron energy distribution in tantalum laser-generated plasma
Authors: Torrisi L. , Mascali D. , Miracoli R. , Gammino S. , Gambino N. , Giuffrida L. , Margarone D.
Published: June 2010

The time and space resolved characterization of laser-generated pulsed plasmas is useful not only for the comprehension of basic phenomena involved in the plasma generation and following supersonic expansion, but it also permits to control the nonequilibrium process that is useful for many applications (e.g., ion implantation). The “on-line” characterization can be performed by means of Langmuir probes, ion collectors, and ion energy analyzers, in order to measure the plasma temperatures and densities of atoms, ions, and electrons. The investigated plasmas were generated by means of laser pulses with intensity of the order of 109 W/cm2. The contemporary characterization of the electron (through the Langmuir probe) and ion energy distribution functions, EEDF and IEDF, respectively, permits to correlate the ion properties, like charge states and temperatures, with the electron properties, like the shape of the EEDF at different times and distances from the ablated target surface.