bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating the diagnosis of chronic rhinosinusitis based on clinical guidelines and endoscopy
Authors: Bhattacharyya Neil , Lee Linda N.
Published: June 2010

Objective

To validate the diagnosis of chronic rhinosinusitis (CRS) according to recent clinical practice guidelines and determine the added utility of nasal endoscopy.

Study Design

Prospective diagnostic cohort study.

Setting

Academic medical center.

Subjects and Methods

A consecutive series of adult patients presenting for evaluation of CRS were prospectively studied with the use of the rhinosinusitis symptom inventory (RSI), nasal endoscopy, and sinus computed tomography (CT). Symptom scores were tabulated from the RSI. Nasal endoscopy was performed to evaluate for purulence or polyps. Sinus CT scans were scored with the Lund system, with the reviewers blinded to the RSI scores and endoscopic findings. The clinical diagnosis of CRS was determined on the basis of the published adult sinusitis guideline criteria and compared with the diagnostic gold standard, CT.

Results

A total of 202 patients were studied. The prevalence of CRS was 39.6 percent, as defined by CT (Lund score ≥ 4). For symptom criteria alone, the sensitivity, specificity, positive predictive value, and negative predictive value were 88.7, 12.3, 39.9, and 62.5 percent, respectively, for CRS (P = 0.82). The addition of endoscopic findings to symptom criteria significantly improved the specificity, predictive value, and negative predictive value to 84.1, 66.0, and 70.3 percent (P < 0.0001). The odds ratio of a true diagnosis of CRS improved from 1.1 to 4.6 (95% confidence interval, 2.3‐9.2). Sensitivity analysis adjusting symptom severity did not significantly alter diagnostic accuracy.

Conclusion

In patients meeting current guideline symptom criteria for CRS, the addition of nasal endoscopy improves diagnostic accuracy and should be emphasized as an early diagnostic tool. Diagnostic endoscopy may help reduce the use of CT, reducing costs and radiation exposure.
Nasal septum to columella attachment: A major tip support?
Authors: Ordóñez‐Ordóñez Leonardo Elías , Navarro‐García Usmaila S. , Angulo‐Martínez Esther Sofía
Published: June 2010

Objective

To determine whether surgical section of attachment of the medial crural footplates to the quadrangular cartilage produces loosening of the nasal tip.

Study Design

Prospective, observational, before‐and‐after study.

Setting

Tertiary care center.

Subjects and Methods

Hispanic patients undergoing septoplasty who required a transfixion incision were included. A six‐month postoperative assessment of the nasal tip support was compared with preoperative values. As measures of the nasal tip support, we included tip recoil test, nasolabial angle, tip rotation angle, nasofacial angle, and the Goode method for determining tip projection.

Results

Twenty‐seven patients completed the follow‐up, and their results are reported. There were no statistically significant differences after septoplasty in any of the five measurements used to assess the nasal tip support (P > 0.05).

Conclusion

In this preliminary cohort of Hispanic patients, surgical section of the attachment of the medial crural footplates to the quadrangular cartilage does not produce significant changes in nasal tip support.
KERNELS OF MORPHISMS BETWEEN INDECOMPOSABLE INJECTIVE MODULES
Authors: FACCHINI ALBERTO , ECEVIT ŞULE , KOŞAN M. TAMER
Published: June 2010

We show that the endomorphism rings of kernels ker ϕ of non-injective morphisms ϕ between indecomposable injective modules are either local or have two maximal ideals, the module ker ϕ is determined up to isomorphism by two invariants called monogeny class and upper part, and a weak form of the Krull–Schmidt theorem holds for direct sums of these kernels. We prove with an example that our pathological decompositions actually take place. We show that a direct sum ofnkernels of morphisms between injective indecomposable modules can have exactlyn! pairwise non-isomorphic direct-sum decompositions into kernels of morphisms of the same type. IfERis an injective indecomposable module andSis its endomorphism ring, the duality Hom(−,ER) transforms kernels of morphismsER→ERinto cyclically presented left modules over the local ringS, sending the monogeny class into the epigeny class and the upper part into the lower part.
Task-priority motion planning of underactuated systems: an endogenous configuration space approach – ERRATUM
Authors: Ratajczak Adam , Karpińska Joanna , Tchoń Krzysztof
Published: June 2010

Figures 2 and 5 were incorrectly reproduced in the above publication (Ratajczak et al. 2009). The figures are reproduced below in their correct form.
Fig. 2.

Task-priority algorithm (both S1 and S2).

Fig. 5.

Single-task algorithm (only S1).
The Linguistic Affiliation Constraint and phoneme recognition in diglossic Arabic
Authors: SAIEGH-HADDAD ELINOR , LEVIN IRIS , HENDE NAREMAN , ZIV MARGALIT
Published: June 2010

This study tested the effect of the phoneme's linguistic affiliation (Standard Arabic versus Spoken Arabic) on phoneme recognition among five-year-old Arabic native speaking kindergarteners (N=60). Using a picture selection task of words beginning with the same phoneme, and through careful manipulation of the phonological properties of target phonemes and distractors, the study showed that children's recognition of Standard phonemes was poorer than that of Spoken phonemes. This finding was interpreted as indicating a deficiency in the phonological representations of Standard words. Next, the study tested two hypotheses regarding the specific consequences of under-specified phonological representations: phonological encoding versus phonological processing. These hypotheses were addressed through an analysis of the relative power of distractors. The findings revealed that children's difficulty in accessing Standard Arabic phonemes was due to a difficulty in the phonological encoding of Standard words. We discuss the implications of the findings for language and literacy development in diglossic Arabic.
The Brauer–Manin obstruction for integral points on curves
Authors: HARARI DAVID , VOLOCH JOSÉ FELIPE
Published: June 2010

We discuss the question of whether the Brauer–Manin obstruction is the only obstruction to the Hasse principle for integral points on affine hyperbolic curves. In the case of rational curves we conjecture a positive answer, we prove that this conjecture can be given several equivalent formulations and we relate it to an old conjecture of Skolem. Finally, we show that for elliptic curves minus one point a strong version of the question (describing the set of integral points by local conditions) has a negative answer.
Systems theory and cascades in developmental psychopathology
Authors: Cox Martha J. , Mills-Koonce Roger , Propper Cathi , Gariépy Jean-Louis
Published: June 2010

In the wake of prominent theoreticians in developmental science, whose contributions we review in this article, many developmental psychologists came to endorse a systems approach to understanding how the individual, as it develops, establishes functional relationships to social ecological contexts that from birth to school entry rapidly increase in complexity. The concept of developmental cascade has been introduced in this context to describe lawful processes by which antecedent conditions may be related with varying probabilities to specified outcomes. These are understood as processes by which function at one level or in one domain of behavior affect the organization of competency in later developing domains of general adaptation. Here we propose a developmental sequence by which the developing child acquires regulative capacities that are key to adjustment to a society that demands considerable control of emotional and cognitive functions early in life. We report empirical evidence showing that the acquisition of regulative capacities may be understood as a cascade of shifts in control parameters induced by the progressive integration of biological, transactional, and socioaffective systems over development. We conclude by suggesting how the developmental process may be accessed for effective intervention in populations deemed “at risk” for later problems of psychosocial adjustment.
Developmental cascades of peer relations and symptoms of externalizing and internalizing problems from kindergarten to fourth-grade elementary school
Authors: van Lier Pol A. C. , Koot Hans M.
Published: June 2010

A developmental cascade model linking symptoms of externalizing and internalizing psychopathology through three indices of peer relational difficulty (peer rejection, peer victimization, friendedness) was tested in a general population sample of 653 children followed annually from kindergarten to fourth grade. Rejection and victimization linked kindergarten externalizing problems with fourth-grade internalizing problems. Transactional links between rejection and victimization were found. In addition, peer rejection added to the development of externalizing problems. Friendedness did not add to the development of externalizing or internalizing problems. Cascade paths were similar for boys and girls. Over the period of kindergarten to fourth grade, psychopathology and peer relations become entangled, and the dynamic interplay between multiple manifestations of poor peer relations ultimately adds to the development of both externalizing and internalizing problems and their cross-time relation. Implications for research and prevention are discussed.
Aggression, social competence, and academic achievement in Chinese children: A 5-year longitudinal study
Authors: Chen Xinyin , Huang Xiaorui , Chang Lei , Wang Li , Li Dan
Published: June 2010

The primary purpose of this longitudinal study was to examine, in a sample of Chinese children (initialMage = 8 years,N= 1,140), contributions of aggression to the development of social competence and academic achievement. Five waves of panel data on aggression and social and school performance were collected from peer evaluations, teacher ratings, and school records in Grades 2 to 5. Structural equation modeling revealed that aggression had unique effects on later social competence and academic achievement after their stabilities were controlled, particularly in the junior grades. Aggression also had significant indirect effects on social and academic outcomes through multiple pathways. Social competence and academic achievement contributed to the development of each other, but not aggression. The results indicate cascade effects of aggression in Chinese children from a developmental perspective.
Psychopathology and social competence during the transition to adolescence: The role of family adversity and pubertal development
Authors: Obradović Jelena , Hipwell Alison
Published: June 2010

This study examined developmental processes linking competence and psychopathology in an urban sample of girls during their transition to adolescence. Longitudinal associations among indices of externalizing symptoms, social competence, and internalizing symptoms were also tested within contexts of family adversity and girls’ pubertal status. Child, parent, and teacher report were employed to assess core constructs across six annual assessment waves, starting at age 9. Results revealed the significant effect of prior levels of externalizing symptoms on changes in social competence and internalizing symptoms, as well as reciprocal relations between social competence and internalizing symptoms. In addition, girl's maladaptive functioning predicted increases in family adversity exposure over time. Last, more mature pubertal status in early assessment waves was linked to an increase in internalizing symptoms; however, this association was reversed by the last assessment, when most girls had reached advance stages of puberty. The timing of these effects reveals important targets for future interventions aimed at promoting the successful adaptation of girls in adolescence.
Effects of childhood conduct problems and family adversity on health, health behaviors, and service use in early adulthood: Tests of developmental pathways involving adolescent risk taking and depression
Authors: Herrenkohl Todd I. , Kosterman Rick , Mason W. Alex , Hawkins J. David , McCarty Carolyn A. , McCauley Elizabeth
Published: June 2010

This study examined a developmental, cascade model that includes childhood risks of conduct problems and family adversity at age 10–12; conduct problems, risk taking, and internalizing during adolescence; and adult outcomes of conduct problems, poor health, health risks, depression, and service use at ages 27 and 30. Analyses showed that childhood conduct problems predicted adolescent conduct problems and risk taking, which in turn, predicted adult conduct problems, health risks, depression, and service use. Childhood family adversity predicted adolescent internalizing, a predictor itself of poor health, depression, and service use at age 27. There was considerable continuity in the same adult outcomes measured over a 3-year period, as well as some cross-domain prediction from variables at age 27 to measures at age 30. Developmental patterns found in these data offer implications for future research and prevention.
The significance of childhood competence and problems for adult success in work: A developmental cascade analysis
Authors: Masten Ann S. , Desjardins Christopher David , McCormick Christopher M. , Kuo Sally I-Chun , Long Jeffrey D.
Published: June 2010

Success in the domain of work is a salient developmental task of adulthood and a key indicator of adaptive function in the evaluation of health and psychopathology. Yet few studies have examined pathways to work competence, especially with strategies testing for cumulative cascade effects over time. Cascade models spanning 20 years were tested via structural equation modeling, linking work competence in early adulthood to antecedent competence in work and other domains of competence in childhood and emerging adulthood. Data were drawn from the Project Competence longitudinal study of 205 school children followed for 20 years. Relative fit of alternative models was evaluated by the Bayesian information criterion. As hypothesized, the effectiveness of adaptive behavior in earlier age-salient developmental task domains forecasted later work competence, which also showed strong concurrent links to competence in other domains. Results suggest there are numerous pathways by which success or failure in major developmental task domains in childhood and adolescence may influence adaptation in other domains and eventually work competence, both concurrently and cumulatively over time. Cascade effects highlight the potential significance for later work competence of childhood conduct (antisocial vs. rule-abiding behavior) and social competence with peers, in addition to the ongoing role that academic attainment may have for work success. Work competence also showed considerable stability over a 10-year period during early adulthood. Implications and applications for future research and intervention are discussed.
Evaluation of the interactionist model of socioeconomic status and problem behavior: A developmental cascade across generations
Authors: Martin Monica J. , Conger Rand D. , Schofield Thomas J. , Dogan Shannon J. , Widaman Keith F. , Donnellan M. Brent , Neppl Tricia K.
Published: June 2010

The current multigenerational study evaluates the utility of the interactionist model of socioeconomic influence on human development (IMSI) in explaining problem behaviors across generations. The IMSI proposes that the association between socioeconomic status (SES) and human development involves a dynamic interplay that includes both social causation (SES influences human development) and social selection (individual characteristics affect SES). As part of the developmental cascade proposed by the IMSI, the findings from this investigation showed that Generation 1 (G1) adolescent problem behavior predicted later G1 SES, family stress, and parental emotional investments, as well as the next generation of children's problem behavior. These results are consistent with a social selection view. Consistent with the social causation perspective, we found a significant relation between G1 SES and family stress, and in turn, family stress predicted Generation 2 (G2) problem behavior. Finally, G1 adult SES predicted both material and emotional investments in the G2 child. In turn, emotional investments predicted G2 problem behavior, as did material investments. Some of the predicted pathways varied by G1 parent gender. The results are consistent with the view that processes of both social selection and social causation account for the association between SES and human development.
Diagrammatic logic applied to a parameterisation process
Authors: DOMÍNGUEZ CÉSAR , DUVAL DOMINIQUE
Published: June 2010

This paper provides an abstract definition of a class of logics, called diagrammatic logics, together with a definition of morphisms and 2-morphisms between them. The definition of the 2-category of diagrammatic logics relies on category theory, mainly on adjunction, categories of fractions and limit sketches. This framework is applied to the formalisation of a parameterisation process. This process, which consists of adding a formal parameter to some operations in a given specification, is presented as a morphism of logics. Then the parameter passing process for recovering a model of the given specification from a model of the parameterised specification and an actual parameter is shown to be a 2-morphism of logics.
Changes in environmentally sensitive productivity and technological modernization in China's iron and steel industry in the 1990s
Authors: FUJII HIDEMICHI , KANEKO SHINJI , MANAGI SHUNSUKE
Published: June 2010

Technological modernization is widely believed to contribute positively both to economic development and to environmental and resource conservation, through improvements in productivity and strengthening of business competitiveness. However, this may not always be true, particularly in the short term, as it requires substantial investments and may impose financial burdens on firms undertaking such investments. This study empirically examines the effects of technological modernization in China's iron and steel industry in the 1990s on conventional economic productivity (CEP) and environmentally sensitive productivities (ESPs). We employ a directional distance function that can handle multiple inputs and outputs to compute relative production efficiencies. We apply these models to the data covering 27 iron and steel firms in China between 1990 and 1999 – a period when the Chinese iron and steel industry modernized rapidly. We find that ESPs have continuously improved, even in the period when the CEP declined.
Validity of Proxy-Based Reports of Impulsivity and Aggression in Chinese Research on Suicidal Behavior
Authors: An Jing , Phillips Michael R. , Conner Kenneth R.
Published: June 2010

Background: In studies about the risk factors for suicidal behavior, the assessment of impulsiveness and aggression often depend on information from proxy informants. Aims: To assess the validity of proxy informants’ reports on impulsiveness and aggression in China. Methods: Modified Chinese versions of the Barratt Impulsiveness Scale (BIS-CV) and the Buss-Perry Aggression Questionnaire (AQ-CV) were administered to 131 suicide attempters treated at a hospital in rural China, to coresident relatives about the attempters, to 131 matched community controls, and to coresident relatives about the controls. Results: BIS-CV and AQ-CV total scores and subscale scores were all significantly higher for suicide attempters than for matched controls. Proxy informants considered subjects slightly more impulsive and aggressive than the subjects reported themselves. Subject-proxy concordance for total BIS-CV and AQ-CV scores were excellent for both attempters and controls (ICCs = 0.76–0.83). Concordance for the three BIS-CV subscales was 0.74–0.81 for attempters and 0.74–0.83 for controls. Concordance for the five AQ-CV subscales was 0.66–0.85 for attempters and 0.56–0.82 for controls. Limitations: Results are based on respondents from a single location in rural China. Conclusions: The results support the validity of the BIS-CV and AQ-CV and of research on suicidal behavior in China that uses proxy-based reports of impulsiveness and aggression.
Vertical structure of small eukaryotes in three lakes that differ by their trophic status: a quantitative approach
Authors: Lepère Cecile , Masquelier Sylvie , Mangot Jean-François , Debroas Didier , Domaizon Isabelle
Published: June 2010

In lakes, the diversity of eukaryotic picoplankton has been recently studied by the analysis of 18S ribosomal RNA gene sequences; however, quantitative data are rare. In this study, the vertical structure and abundance of the small eukaryotic size fraction (0.2–5 μm) were investigated in three lakes by tyramide signal amplification–fluorescent in situ hybridization targeting six phylogenetic groups: Chlorophyta, Haptophyta, Cercozoa, LKM11, Perkinsozoa and fungi. The groups targeted in this study are found in all lakes; however, both the abundance and structure of small eukaryotes are dependent on the system's productivity and depth. These data highlighted the presence of Chlorophyta contributing on an average to 19.3%, 14.7% and 41.2% of total small eukaryotes in lakes Bourget, Aydat and Pavin, respectively. This study also revealed the unexpected importance of Haptophyta, reaching 62.8% of eukaryotes in the euphotic zone of Lake Bourget. The high proportions of these pigmented cells highlight the underestimation of these groups by PCR-based methods. The presence of pigmented Chlorophyta in the deepest zones of the lakes suggests a mixotrophic behaviour of these taxa. We also confirmed the presence of putative parasites such as Perkinsozoa (5.1% of small eukaryotes in Lake Pavin and Bourget) and, with lower abundances, fungi (targeted by the MY1574 probe). Cells targeted by LKM11 probes represented the second group of abundance within heterotrophs. Open questions regarding the functional roles of the targeted groups arise from this study, especially regarding parasitism and mixotrophy, which are interactions poorly taken into account in planktonic food web models.
Immunoneutralization of the aminoprocalcitonin peptide of procalcitonin protects rats from lethal endotoxaemia: neuroendocrine and systemic studies
Authors: Tavares Eva , Miñano Francisco J.
Published: June 2010

Severe sepsis and septic shock are an important cause of mortality and morbidity. These illnesses can be triggered by the bacterial endotoxin LPS (lipopolysaccharide) and pro-inflammatory cytokines, particularly TNF-α (tumour necrosis factor-α) and IL (interleukin)-1β. Severity and mortality of sepsis have also been associated with high concentrations of N-PCT (aminoprocalcitonin), a 57-amino-acid neuroendocrine peptide derived from ProCT (procalcitonin). Previous studies in a lethal model of porcine polymicrobial sepsis have revealed that immunoneutralization with IgG that is reactive to porcine N-PCT significantly improves short-term survival. To explore further the pathophysiological role of N-PCT in sepsis, we developed an antibody raised against a highly conserved amino acid sequence of human N-PCT [N-PCT-(44–57)]. This sequence differs by only one amino acid from rat N-PCT. First, we demonstrated the specificity of this antibody in a well-proven model of anorexia induced in rats by central administration of human N-PCT-(1–57). Next we explored further the therapeutic potential of anti-N-PCT-(44–57) in a rat model of lethal endotoxaemia and determined how this immunoneutralization affected LPS-induced lethality and cytokine production. We show that this specific antibody inhibited the LPS-induced early release of TNF-α and IL-1β and increased survival, even if treatment began after the cytokine response had occurred. In addition, anti-N-PCT-(44–57) may increase long-term survival in LPS-treated rats by up-regulating the late production of counter-regulatory anti-inflammatory mediators such as ACTH (adrenocorticotropic hormone) and IL-10. In conclusion, these results support N-PCT as a pro-inflammatory factor in both the early and the late stages of lethal endotoxaemia, and suggest anti-N-PCT as a candidate for septic shock therapy.
Theoretical study of in-plane response of magnetic field sensor to magnetic beads magnetized by the sensor self-field
Authors: Hansen Troels Borum Grave , Damsgaard Christian Danvad , Dalslet Bjarke Thomas , Hansen Mikkel Fougt
Published: June 2010

We present a theoretical study of the spatially averaged in-plane magnetic field on square and rectangular magnetic field sensors from a single magnetic bead, a monolayer of magnetic beads, and a half-space filled with magnetic beads being magnetized by the magnetic self-field due to the applied bias current through the sensor. The analysis of the single bead response shows that beads always contribute positively to the average magnetic field as opposed to the case for an applied homogeneous magnetic field where the sign of the signal depends on the bead position. General expressions and analytical approximations are derived for the sensor response to beads as function of the bead distribution, the bias current, the geometry and size of the sensor, and the bead characteristics. Consequences for the sensor design are exemplified and it is described how the contribution from the self-field experimentally can be separated from that due to static magnetic fields.
Tight-binding implementation of the microcanonical approach to transport in nanoscale conductors: Generalization and analysis
Authors: Ercan İlke , Anderson Neal G.
Published: June 2010

Bushong, Sai, and Di Ventra (BSD) recently demonstrated that steady-state transport can emerge solely from quantum dynamics in a globally closed system consisting of a nanoscale conductor bridging two electrodes by Bushong et al. [Nano Lett. 5, 2569 (2005)]. They reported calculations, based on a simple tight-binding implementation of the “microcanonical” approach (TBIMCA) by Di Ventra and Todorov [J. Phys.: Condens. Matter 16, 8025 (2004)], in which a steady-state conductor current consistent in magnitude with the quantum conductance G0=2e2/h is established after an initial bias-induced imbalance in electrode populations begins to equalize. In this work, BSD’s TBIMCA is generalized, and their expressions for the time-dependent current and local occupation functions are shown to apply only to a restricted class of structures. Calculations of the current dynamics and local occupation functions, based on the generalized formalism, are then presented for a wide variety of electrode-conductor-electrode geometries. These calculations provide a more comprehensive characterization of the TBIMCA, enable identification of the conditions under which signature features of nanoscale transport emerge, and show that the emergence of these features hinges critically on details of the structure geometry. This structure dependence represents an important consideration for application of the TBIMCA to the modeling of transport through nanostructures and should be recognized in any attempt to identify and explain signature features of nanoscale transport within this approach.
Study of domain reversal and its field-dependence in epitaxial BaTiO3 thin films
Authors: Li Jianheng , Liu Zhifu , Wessels B. W.
Published: June 2010

Polarization switching dynamics were investigated in ferroelectric BaTiO3 epitaxial layers. Using the linear electro-optic (EO) effect, the polarization switching was measured under pulse excitation. The switching is given by a simple analytical model where the EO response follows an extended exponential function in time in the form of [1−exp−(t/τ)β], where τ and β are kinetic parameters, which depend on field. The parameter τ has the value of several milliseconds and β ranges from 0.2 to 0.3. The activation field α for domain growth was measured as a function of pulse width and field strength whereby the value of α decreases as the pulse width decreases. The activation field for the application of a pulse is higher than that upon the removal of the pulse. The difference is attributed to the existence of a depolarization field in the film in the direction of the external electric field.
Nanostructural interpretation for elastic softening of amorphous carbon induced by the incorporation of silicon and hydrogen atoms
Authors: Kumagai Tomohisa , Sawai Shu , Choi Junho , Izumi Satoshi , Kato Takahisa
Published: June 2010

First-principles molecular dynamics simulation is used to investigate the elastic softening of amorphous carbon on the incorporation of silicon and hydrogen atoms, and the mechanisms responsible for this phenomenon are discussed from the viewpoint of atomic structure. With increasing silicon incorporation, it is found that the bulk moduli of silicon-incorporated amorphous carbon (a-C:Si) and silicon-incorporated hydrogenated amorphous carbon (a-C:Si:H) decrease, whereas the total number of sp3-bonded atoms increases. This is explained on the basis of interatomic bond structures such as: increasing silicon incorporation reduces the number of interatomic (both single and double) bonds between carbon atoms while increasing the number of interatomic bonds between silicon and carbon atoms. Furthermore, for a given density and silicon content, it is found that the bulk modulus of the a-C:Si structure is greater than that of the a-C:Si:H structure, though their interatomic bond structures are similar. The reduced bulk modulus with incorporated hydrogen atoms is found to be due to enhanced internal displacement, which can be understood as atomic displacement in deformed structures: that is, hydrogen-terminated atoms are not bound by interatomic bonds originating from the hydrogen atoms, whereas atoms that bond only to carbon or silicon are bound by all the interatomic bonds.
Nonlinear frequency-mixing photoacoustic imaging of a crack: Theory
Authors: Gusev V. , Chigarev N.
Published: June 2010

One-dimensional theory of the nonlinear frequency-mixing photoacoustic crack imaging is developed. This imaging can be realized through the excitation of the crack by two laser beams independently modulated in intensity at two very different frequencies ωH⪢ωL and the detection of the components of photoacoustic spectrum at frequencies ωH±nωL with an integer n. It is predicted that the high contrast of this imaging can be caused by strong dependence of the efficiency of photoacoustic conversion on the mechanical state of the crack, i.e., on whether the crack is open or is at least partially closed due to the contacts between the crack faces. The theory relates earlier experimental observation of the large number of the side-lobes ωH±nωL to strong bimodular nonlinearity of the crack. In response to sinusoidal modulation of pump laser intensity at low frequency ωL the rigidity of the crack varies in a strongly nonsinusoidal manner through abrupt jumps between its value corresponding to an open soft state of the crack and its value corresponding to a much more rigid closed state of the crack. Parametric interaction of the acoustic waves generated by probe laser radiation harmonically modulated in intensity at high frequency ωH with this strongly nonsinusoidal motion excites multiple side-lobes around ωH. The theory indicates that information on the crack rigidity could be obtained from the measurements of photoacoustic conversion efficiency and that the information on the parameters of force/width relation of the crack can be obtained from the measurements of the dependence of the side-lobes spectrum on the pump laser intensity.
Variational derivation of second-order slip coefficients on the basis of the Boltzmann equation for hard-sphere molecules
Authors: Cercignani Carlo , Lorenzani Silvia
Published: June 2010

The objective of the present paper is to provide an analytic expression for the first- and second-order velocity slip coefficients. Therefore, gas flow rates in microchannels have been rigorously evaluated in the near-continuum limit by means of a variational technique which applies to the integrodifferential form of the Boltzmann equation based on the true linearized collision operator. The diffuse-specular reflection condition of Maxwell’s type has been considered in order to take into account the influence of the accommodation coefficient on the slip parameters. The polynomial form of the Knudsen number obtained for the Poiseuille mass flow rate and the values of the velocity slip coefficients, found on the basis of our variational solution of the linearized Boltzmann equation for hard-sphere molecules, are analyzed in the frame of potential applications of classical continuum numerical tools in simulations of microscale flows.
ac field-switchable magnetic properties of two-dimensional networked nanosize magnets
Authors: Mito Masaki , Ogawa Masashi , Deguchi Hiroyuki , Yamashita Masahiro , Miyasaka Hitoshi
Published: June 2010

The magnetic properties of interacting magnetic nanoparticles were investigated by examining two kinds of two-dimensional networked single-molecule magnets (SMMs). Through nonlinear magnetic susceptibility measurements, we observed a switchable transformation of the magnetic response upon applying an ac magnetic field to the SMMs. The magnetic properties depending on the measurement time-scale can be understood as a competition of the magnetic interaction between the constituents (i.e., SMMs or SMM aggregates) and the strong Ising nature of the individual constituents. In high-frequency ac fields, the Ising nature of the SMM induces magnetic behavior due to either the aggregate consisting of several SMMs or the individual SMMs, rather than a static response due to magnetic ordering. The magnetic state at the low-frequency limit was investigated through thermoremanent magnetization measurements, and a relaxation of the aggregates in a manner similar to the Griffiths phase was observed in the first material, [Mn4(hmp)4Br2(OMe)2(dcn)2]⋅0.5H2O⋅2THF. The second material, [Mn4(hmp)6(dcn)2](ClO4)2, with strong dipolar interaction between aggregates, exhibited a glass-type system-wide response rather than a relaxation of the aggregates. Our present study on these regularly networked SMM systems demonstrated the existence of a switchable magnetic phenomenon induced by ac magnetic fields. It is difficult to investigate this kind of phenomenon in diffused magnetic nanoparticles with random location and distribution of both particle size and interparticle distance.
Microwave assisted switching mechanism and its stable switching limit
Authors: Okamoto S. , Igarashi M. , Kikuchi N. , Kitakami O.
Published: June 2010

Microwave assisted switching (MAS) of magnetization has been intensively studied as an alternative technique for ultrahigh density magnetic recording. In this paper, comparison between the Landau–Lifshitz–Gilbert simulation and the analytical model in the rotating frame {Bertotti et al., [Phys. Rev. Lett. 86, 724 (2001)]} reveals that the switching behaviors of MAS can be clearly divided into two groups, that is, stable and unstable switching regions, depending on the frequency and amplitude of the ac field. The stable switching exhibits small switching field and narrow switching field distribution, and perfectly coincides with by the analytical model. Furthermore, in this region, the Sharrock type thermal fluctuation formula can be applicable to the MAS at finite temperature. On the other hand, for the unstable switching, the switching field is rather large and the SDF becomes very broad. Obviously, the former is preferable for the practical application of MAS. The critical frequency of the ac field for the limit of stable switching is almost proportional to the ac field amplitude.
Note: A low leakage liquid seal for micromachined gas valves
Authors: Evans Allan T. , Gianchandani Yogesh B.
Published: June 2010

We report a method for addressing gas leakage in micromachined valves. The valves used for evaluating the proposed concept utilize a silicon valve seat that is bonded to a glass substrate and actuated by a piezoelectric stack, all of which are assembled within a ceramic package. The sealing method uses the capillary forces of a liquid sealant on the valve seat to reduce gas leakage below measurable limits. The gas leak rates are compared in valves with and without the seal enhancement. For example, a valve closes against 13.5 kPa with 10 V actuation, compared to 40 V required without the enhancement. Leakage is also evaluated for liquid flow.
FePt
–
TiO
2
exchange coupled composite media with well-isolated columnar microstructure for high density magnetic recording
Authors: Jiang C. J. , Chen J. S. , Hu J. F. , Chow G. M.
Published: June 2010

We reported the fabrication of (001) textured FePt–TiO2 exchange coupled composite (ECC) media including hard/soft bilayer and multilayer with well isolated columnar microstructures. The magnetic anisotropy of FePt–TiO2 was adjusted by applying various substrate bias during film deposition. The cross-sectional transmission electron microscopy images showed isolated granular microstructures in single hard layer, bilayer, and multilayer media. For the bilayer media, it was observed that both the coercivity and magnetization squareness of composite media decreased with increasing thickness of the soft layer. A soft layer with the thickness of 4 nm was more effective to significantly reduce the switching field and maintain a higher thermal stability factor than that of others. Incoherent switching behavior was observed as the soft layer thickness was increased to 6 nm. For multilayer media, it was found that the out-of-plane coercivity decreased to 6.5 kOe, which was close to half of that of the single hard layer. However, the thermal stability factor of the multilayer media slightly decreased compared with the single hard layer and bilayer media due to finite thickness. The results suggested a way to obtain the adjustable anisotropy for ECC media in high density magnetic recording application.
Scaling effects of relaxor-PbTiO3 crystals and composites for high frequency ultrasound
Authors: Lee Hyeong Jae , Zhang Shujun , Shrout Thomas R.
Published: June 2010

The dielectric and piezoelectric properties of Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) and Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN-PMN-PT) ferroelectric single crystals were investigated as a function of thickness/scale in monolithic and piezoelectric/polymer 1–3 composites. For the case of PMN-PT single crystals, the dielectric (ε33T/ε0) and electromechanical properties (k33) were found to significantly decrease with decreasing thickness (500–40 μm), while minimal thickness dependency was observed for PIN-PMN-PT single crystals. Temperature dependent dielectric behavior of the crystals suggested that the observed thickness dependence in PMN-PT was strongly related to their relatively large domain size (>10–20 μm). As anticipated, 1–3 composite comprised of PIN-PMN-PT crystals exhibited superior properties to that of PMN-PT composite at high frequencies (>20 MHz). However, the observed couplings, being on the order of 80%, were disappointedly low when compared to their monolithic counterparts, the result of surface damage introduced during the dicing process, as evidenced by the broadened [002] peaks in the x-ray diffraction pattern.
Study of the reflectivity of neutron supermirrors influenced by surface oil layers
Authors: Veres Tamás , Cser László
Published: June 2010

Neutron guides made of supermirror-coated glass are important components of most neutron scattering instruments, thus their quality and possible deterioration due to various deleterious effects (e.g., surface contamination or defects) deserve careful examination. The modification of the reflectivity of supermirrors and the transmission of neutron guides due to surface contamination with hydrocarbon oil has been investigated using neutron reflectometry together with model calculations. A significant loss in the neutron reflectivity was observed for supermirrors covered with thin hydrocarbon oil films, which were confirmed in model calculations. Simulations carried out for several typical arrangements show drastic decreases in the transmitted neutron flux of neutron guides. These simulations show that determining the distortion of the beam profile (using a slit or a pin hole) enables the detection of oil contamination even in an operating neutron guide.
Photoionization of iodine atoms: Rydberg series which converge to the I+(S1)←I(P23/2) threshold
Authors: Eypper Marie , Innocenti Fabrizio , Morris Alan , Stranges Stefano , West John B. , King George C. , Dyke John M.
Published: June 2010

Relative partial photoionization cross sections and angular distribution parameters β have been measured for the first and fourth (5p)−1 photoelectron (PE) bands of atomic iodine by performing angle-resolved constant-ionic-state (CIS) measurements on these PE bands between the D12 and S10 (5p)−1 ionic thresholds in the photon energy region of 12.9–14.1 eV. Rydberg series arising from the 5p→ns and 5p→nd excitations are observed in both the first PE band, I+(P32)←I(P23/2), and the fourth PE band, I+(D12)←I(P23/2), CIS spectra. For each Rydberg state, the resonance energy, quantum defect, linewidth, line shape, and photoelectron angular distribution parameter β have been determined. For the β-plots for each PE band, only resonances corresponding to 5p→nd excitations are observed; no resonances were seen at photon energies corresponding to the 5p→ns resonances in the CIS spectra. The β-plots are interpreted in terms of the parity unfavored channel with jt=4 being the major contributor at the 5p→nd resonance positions, where jt is the quantum number for angular momentum transferred between the molecule, and the ion and photoelectron. Comparison of the results obtained with those published for bromine shows reasonably good agreement for the CIS spectra but poor agreement for the β-plots. It appears that parity unfavored channels are playing a greater role in the valence (np)−1 ionization of atomic iodine than in the corresponding ionization of atomic bromine.
Design and construction of a novel tribometer with online topography and wear measurement
Authors: Korres Spyridon , Dienwiebel Martin
Published: June 2010

We present a novel experimental platform that links topographical and material changes with the friction and wear behavior of oil-lubricated metal surfaces. This concept combines state-of-the-art methods for the analysis of the surface topography on the micro- and nanoscale with the online measurement of wear. At the same time, it allows for frictional and lateral force detection. Information on the topography of one of the two surfaces is gathered in situ with a three-dimensional (3D) holography microscope at a maximum frequency of 15 frames/s and higher resolution images are provided at defined time intervals by an atomic force microscope. The wear measurement is conducted online by means of radio nuclide technique. The quantitative measurement of the lateral and frictional forces is conducted with a custom-built 3D force sensor. The surfaces can be lubricated with an optically transparent oil or water. The stability and precision of the setup have been tested in a model experiment. The results show that the exact same position can be relocated and examined after each load cycle. Wear and topography measurements were performed with a radioactive labeled iron pin sliding against an iron plate.
High-shear-rate capillary viscometer for inkjet inks
Authors: Wang Xi , Carr Wallace W. , Bucknall David G. , Morris Jeffrey F.
Published: June 2010

A capillary viscometer developed to measure the apparent shear viscosity of inkjet inks at high apparent shear rates encountered during inkjet printing is described. By using the Weissenberg–Rabinowitsch equation, true shear viscosity versus true shear rate is obtained. The device is comprised of a constant-flow generator, a static pressure monitoring device, a high precision submillimeter capillary die, and a high stiffness flow path. The system, which is calibrated using standard Newtonian low-viscosity silicone oil, can be easily operated and maintained. Results for measurement of the shear-rate-dependent viscosity of carbon-black pigmented water-based inkjet inks at shear rates up to 2×105 s−1 are discussed. The Cross model was found to closely fit the experimental data. Inkjet ink samples with similar low-shear-rate viscosities exhibited significantly different shear viscosities at high shear rates depending on particle loading.
Thermal transport properties of graphene-based ferromagnetic/singlet superconductor/ferromagnetic junctions
Authors: Salehi Morteza , Alidoust Mohammad , Rahnavard Yousef , Rashedi Gholamreza
Published: June 2010

We present an investigation of heat transport in gapless graphene-based ferromagnetic/singlet superconductor/ferromagnetic junctions. We find that unlike the uniform increase in the thermal conductance versus temperature, the thermal conductance exhibits intensive oscillatory behavior versus width of sandwiched s-wave superconducting region between the two ferromagnetic layers. This oscillatory form rises from interference of the massless Dirac fermions in graphene. Also we find that thermal conductance versus exchange field h displays a minimal value at h/Ef≃1 within the low temperature regime where this finding demonstrates that propagating modes of the Dirac fermions in this value reach to their minimum numbers and verify the previous results for electronic conductance. We find that for thin widths of superconducting region, the thermal conductance versus temperature shows linear increment, i.e., Γ∝T. At last we propose an experimental setup to detect our predicted effects.
An integrated microfluidic system for isolation, counting, and sorting of hematopoietic stem cells
Authors: Wu Huei-Wen , Hsu Ruo-Chi , Lin Chun-Che , Hwang Shiaw-Min , Lee Gwo-Bin
Published: June 2010

This study reports an integrated microfluidic system capable of isolation, counting, and sorting of hematopoietic stem cells (HSCs) from cord blood in an automatic format by utilizing a magnetic-bead-based immunoassay. Three functional modules, including cell isolation, cell counting, and cell sorting modules are integrated on a single chip by using microfluidic technology. The cell isolation module is comprised of a four-membrane-type micromixer for binding of target stem cells and magnetic beads, two pneumatic micropumps for sample transport, and an S-shaped channel for isolation of HSCs using a permanent magnet underneath. The counting and sorting of HSCs are performed by utilizing the cell counting and sorting modules. Experimental results show that a separation efficiency as high as 88% for HSCs from cord blood is achieved within 40 min for a sample volume of 100 μl. Therefore, the development of this integrated microfluidic system may be promising for various applications such as stem cell research and cell therapy.
Electrostatic diagnostics of nanosecond pulsed electron beams in a Malmberg–Penning trap
Authors: Paroli B. , Bettega G. , Maero G. , Romé M. , Norgia M. , Pesatori A. , Svelto C.
Published: June 2010

A fast electrostatic diagnostic and analysis scheme on nanosecond pulsed beams in the keV energy range has been developed in the Malmberg–Penning trap ELTRAP. Low-noise electronics has been used for the detection of small induced current signals on the trap electrodes. A discrete wavelet-based procedure has been implemented for data postprocessing. The development of an effective electrostatic diagnostics together with proper data analysis techniques is of general interest in view of deducing the beam properties through comparison of the postprocessed data with the theoretically computed signal shape, which contains beam radius, length, and average density as fit parameters.