bluuebunny/crossref_metadata_2025 huggingface dataset:
Age Decreases Endothelial Progenitor Cell Recruitment Through Decreases in Hypoxia-Inducible Factor 1α Stabilization During Ischemia
Authors: Chang Eric I. , Loh Shang A. , Ceradini Daniel J. , Chang Edward I. , Lin Shin-e , Bastidas Nicholas , Aarabi Shahram , Chan Denise A. , Freedman Michael L. , Giaccia Amato J. , Gurtner Geoffrey C.
Published: November 2007

Background—

Advanced age is known to impair neovascularization. Because endothelial progenitor cells (EPCs) participate in this process, we examined the effects of aging on EPC recruitment and vascular incorporation.

Methods and Results—

Murine neovascularization was examined by use of an ischemic flap model, which demonstrated aged mice (19 to 24 months) had decreased EPC mobilization (percent mobilized 1.4±0.2% versus 0.4±0.1%,
P
<0.005) that resulted in impaired gross tissue survival compared with young mice (2 to 6 months). This decrease correlated with diminished tissue perfusion (
P
<0.005) and decreased CD31
+
vascular density (
P
<0.005). Gender-mismatched bone marrow transplantation demonstrated significantly fewer chimeric vessels in aged mice (
P
<0.05), which confirmed a deficit in bone marrow–mediated vasculogenesis. Age had no effect on total EPC number in mice or humans. Reciprocal bone marrow transplantations confirmed that impaired neovascularization resulted from defects in the response of aged tissue to hypoxia and not from intrinsic defects in EPC function. We demonstrate that aging decreased hypoxia-inducible factor 1α stabilization in ischemic tissues because of increased prolyl hydroxylase–mediated hydroxylation (
P
<0.05) and proteasomal degradation. This resulted in a diminished hypoxia response, including decreased stromal cell–derived factor 1 (
P
<0.005) and vascular endothelial growth factor (
P
<0.0004). This effect can be reversed with the iron chelator deferoxamine, which results in hypoxia-inducible factor 1α stabilization and increased tissue survival.

Conclusions—

Aging impairs EPC trafficking to sites of ischemia through a failure of aged tissues to normally activate the hypoxia-inducible factor 1α–mediated hypoxia response.
Osteogenesis Associates With Inflammation in Early-Stage Atherosclerosis Evaluated by Molecular Imaging In Vivo
Authors: Aikawa Elena , Nahrendorf Matthias , Figueiredo Jose-Luiz , Swirski Filip K. , Shtatland Timur , Kohler Rainer H. , Jaffer Farouc A. , Aikawa Masanori , Weissleder Ralph
Published: November 2007

Background—

Arterial calcification is associated with cardiovascular events; however, mechanisms of calcification in atherosclerosis remain obscure.

Methods and Results—

We tested the hypothesis that inflammation promotes osteogenesis in atherosclerotic plaques using in vivo molecular imaging in apolipoprotein E
−/−
mice (20 to 30 weeks old, n=35). A bisphosphonate-derivatized near-infrared fluorescent imaging agent (excitation 750 nm) visualized osteogenic activity that was otherwise undetectable by x-ray computed tomography. Flow cytometry validated the target specifically in osteoblast-like cells. A spectrally distinct near-infrared fluorescent nanoparticle (excitation 680 nm) was coinjected to simultaneously image macrophages. Fluorescence reflectance mapping demonstrated an association between osteogenic activity and macrophages in aortas of apolipoprotein E
−/−
mice (
R
2
=0.93). Intravital dual-channel fluorescence microscopy was used to further monitor osteogenic changes in inflamed carotid arteries at 20 and 30 weeks of age and revealed that macrophage burden and osteogenesis concomitantly increased during plaque progression (
P
<0.01 and
P
<0.001, respectively) and decreased after statin treatment (
P
<0.0001 and
P
<0.05, respectively). Fluorescence microscopy on cryosections colocalized near-infrared fluorescent osteogenic signals with alkaline phosphatase activity, bone-regulating protein expression, and hydroxyapatite nanocrystals as detected by electron microscopy, whereas von Kossa and alizarin red stains showed no evidence of calcification. Real-time reverse-transcription polymerase chain reaction revealed that macrophage-conditioned media increased alkaline phosphatase mRNA expression in vascular smooth muscle cells.

Conclusions—

This serial in vivo study demonstrates the real-time association of macrophage burden with osteogenic activity in early-stage atherosclerosis and offers a cellular-resolution tool to identify preclinical microcalcifications.
Names That Can Be Said of Everything: Porphyrian Tradition and 'Transcendental' Terms in Twelfth-Century Logic
Authors: Valente Luisa
Published: November 2007

In an article published in 2003, Klaus Jacobi—using texts partially edited in De Rijk's Logica Modernorum—demonstrated that twelfth-century logic contains a tradition of reflecting about some of the transcendental names (nomina transcendentia). In addition to reinforcing Jacobi's thesis with other texts, this contribution aims to demonstrate two points: 1) That twelfth-century logical reflection about transcendental terms has its origin in the logica vetus, and especially in a passage from Porphyry Isagoge and in Boethius's commentary on it. In spite of the loss of the major part of the Aristotelian corpus, the twelfth-century masters in logic still received some Aristotelian theses concerning the notions of one and being via Porphyry and Boethius; on the basis of such theses, they were able to elaborate a sort of proto-theory of the transcendentals as trans-categorical terms. 2) That this theory is centred on the idea that there exists a particular group of names which have the property that they can be said of everything; this group includes "being", "one", "thing" and "something" (ens, unum, res, aliquid). Twelfth-century masters in logic try to question the (originally Aristotelian) thesis that these terms are equivocal, although they do not deny it completely.
The Forum on China-Africa Cooperation (FOCAC)
Authors: Naidu Sanusha
Published: November 2007

FOCAC 2006 concluded a year that was dubbed by the Chinese leadership as China's ‘Year of Africa’. On the surface, the ‘Year of Africa’ demonstrated a striking success for China. However, there are important factors that can undermine the relationship between Africa and China. The aim of this article is to explore whether the future of FOCAC can and would strengthen relations between Africa and China. What are the threats to FOCAC's future? To what extent are the commitments of FOCAC realistic? And more importantly, whose interests does FOCAC serve?
Uniaxial Compressive Properties of Bismaleamid-coated Carbon Microballoons
Authors: Carlisle K.B. , Chawla K.K. , Koopman M. , Gladysz G.M. , Lewis M.
Published: November 2007

A uniaxial compression technique employing a nanoindenter equipped with a flat-ended cylindrical tip is used to evaluate the performance of carbon microballoons (CMBs) precipitation-coated with a bismaleamid (APO-BMI) polymer. This coating will eliminate the size and density induced segregation of APO-BMI and CMBs during mold filling and the potentially damaging mixing step wherein CMBs and powdered binder pre-polymer are blended prior to foam molding. To augment the molding of syntactic foams directly from coated CMBs and to aid in the development of a constitutive model for a three-phase syntactic foam, mechanical property evaluation of the coated CMBs is needed. Cured, APO-BMI coated and uncoated CMBs (0.192 g/cm3 tap density) are compressed uniaxially using a modified nanoindenter to obtain the compressive properties of the CMBs in both conditions. These properties included strain-to-failure, failure load, displacement-at-failure, and work of fracture. The 0.192 g/cm 3 tap density CMBs' behavior followed the prior inter-tap density trends between compressive strain and diameter and failure load versus stiffness. The coating is determined to have no statistically significant effect on the mechanical properties of the CMBs. From the combination of this information, the effect of an APO-BMI coating on CMBs of any tap density is inferred.
A Comparison of the CIE and Uchida Whiteness Formulae as Predictor of Average Visual Whiteness Evaluation of Textiles
Authors: Jafari Razieh , Amirshahi Seyed Hossein
Published: November 2007

The performance of the CIE whiteness formula is evaluated visually by using the pair comparison method and compared with the new whiteness index suggested by Uchida. Twelve white samples are selected from 113 prepared white fabrics and their whiteness indices and tinting factors are calculated by CIE as well as Uchida whiteness indices. Some of the selected samples do not satisfy the CIE limitation conditions for evaluation of whiteness by this formula. Generally, the results of visual judgments show the priority of CIE formula over the Uchida index and this formula still correlate better than Uchida index with visual assessments for both in and the out of boundary white fabrics.
Using Fiber Elongation to Improve Genetic Screening in Cotton Breeding Programs
Authors: Benzina H. , Hequet E. , Abidi N. , Gannaway J. , Drean J.-Y. , Harzallah O.
Published: November 2007

In this study, the bundle elongation and tenacity of cotton fibers were measured using a modified tensile testing instrument to which Pressley clamps (1/8” gage length) were adapted. 32 cotton genotypes with a range of bundle tenacity and elongation were carefully selected based on their distinct physical properties. The work of rupture was calculated from the load vs. elongation curves for each type of cotton. Results demonstrated the importance of fiber bundle elongation in the work of rupture of fiber bundles, which is critically important to processing performance. This study lays a foundation for future efforts to calibrate the high volume instrument elongation measurements and to breed new cultivars with improved work of rupture. This should result in lower fiber breakage when the cotton fibers are submitted to different mechanical stresses (ginning, carding, spinning, and weaving).
Automatic tuning of PID controllers using a combined time- and frequency-domain method
Authors: Thomson M. , Cassidy P.G. , Sandoz D.J.
Published: November 2007

The paper describes an automatic tuning method for the design of PID controllers. Its starting point is the requirement for accurate modelling of process deadtime which is calculated from a discrete model description of the process. Controller design is achieved by a combination of pole-zero cancellation and frequency-response methods which ensures that the system exhibits favourable gain and phase characteristics and good relative stability even for processes with large deadtime. Results are presented for the control of a steam/water heat exchanger and illustrates the usefulness of this technique.
Microprocessor-controlled power converter using single bridge rectifier and GTO current switch
Authors: John Hill R. , Luo Fang L.
Published: November 2007

A four-quadrant AC-fed converter for a DC machine drive using a single bridge thyristor fully controlled rectifier with GTO (gate turn-off) thyristor zero-current reversing switch is described. The circuit has the advantages of no circulating currents and very short current commutation time. Microprocessor-based control techniques are described which achieve optimum transient operation of the converter.
Measurements of three-dimensional flow using a multi-tube twin-wire resistance probe manometer
Authors: Liu C.Y. , Gooi B.C.
Published: November 2007

A computer-controlled three-dimensional flow measurement system using a hemispherical five-hole Pitot probe in conjunction with a multi-tube twin-wire resistance probe manometer was derived. The system is capable of performing a measurement in 2.5 seconds. Application of such a system was demonstrated through the measurement of the vortex flow behind a model delta wing.
Adaptive deadbeat control of instrument servos
Authors: Hamza M.H.
Published: November 2007

An adaptive controller is presented for achieving deadbeat response in instrument servos with slowly time-varying parameters. Simulation and experimental results are presented. The controller is realised using a microcomputer. The controller is effective also when the servo contains small amounts of backlash and deadzone. Several versions of the control algorithm are described.
The delay operator z-1 - inappropriate for use in recursive digital filters?
Authors: Goodall R.M.
Published: November 2007

The paper questions the appropriateness of using the delay operator z-1 for recursive digital filters, particularly when applied to the realisation of digital control. The well known problems of coefficient sensitivity at high sample frequencies are reviewed, and the fundamental reason for this lack of robustness is identified. An analogy is used to argue that the approach whereby digital filters are designed using discrete transfer functions in z is, in fact, mathematically dubious, perhaps unperceived by their users, and that the sensitivity problems are inevitable when z is used. The analogy is extended to argue strongly for using an alternative, the δ operator, which inherently avoids the problem. Some of the implications of using the new operator are assessed, but the main purpose of the paper is to challenge the established practice of using the z operator.
On-line steady-state optimisation of nonlinear constrained processes with slow dynamics
Authors: Zhang H. , Roberts P.D.
Published: November 2007

A scheme for on-line optimisation of constrained nonlinear processes with slow dynamics is suggested and applied to a continuous reactor process. A two-model adaptive mechanism, dynamic and steady state, is used in the scheme. The dynamic model is used to approximate the process locally at each working point for the purpose of estimating steady-state derivatives, and the steady-state model is used for model-based optimisation. The performance lost caused by the inaccuracy of the steady-state model is compensated for by derivatives information which is obtained from dynamic data. The correct optimum can be achieved on-line even if both models are very rough. As shown in applications, the scheme is suited to various types of constraints and nonlinearities and is noise-insensitive.
A reduced order self-tuning controller
Authors: Goodhart S.G. , Burnham K.J. , James D.J.G.
Published: November 2007

As industrial users attempt to control systems exhibiting fast dynamic response characteristics, the demand for higher sampling rates and hence rapid controller calculations is becoming more apparent. This problem is compounded when considering the application of self-tuning control to non-linear systems exhibiting such characteristics, where, in order to maintain integrity of the self-tuner, enhanced estimation algorithms with increased computational complexities are required. In this paper a reduced order state-space self-tuning controller is proposed and its performance is compared by simulation studies to that of a standard implicit delay state-space self-tuning scheme. Whilst the same control objectives are achieved in a compatible manner it is shown that the reduced order scheme is significantly less computationally intensive and, as such, reduces the effects of computational delay in the overall closed-loop self-tuning scheme.
State-space approaches to H-infinity control for infinite-dimensional linear systems
Authors: Curtain Ruth F.
Published: November 2007

The problem of H-infinity control is introduced and formulated as a state-space problem. The main finite-dimensional results are reviewed, a survey of recent results for infinite-dimensional systems is presented and open problems are suggested.
Electromagnetic interference considerations for automated welding cells
Authors: Stone D. , Smith J.S. , Lucas J.
Published: November 2007

The paper concerns a systematic approach to transient-noise suppression which is essential for the development of automated TIG (Tungsten-Inert-Gas) welding systems for industry. The principal source of noise is the initiation of the arc both at the start of and during the welding process. Arc initiation is attained by a number of techniques involving high voltages and high frequencies. The solution of two case studies involving DC and AC (mains) TIG welding have been given in detail. The worst case of interference occurs for AC (mains) TIG welding because it is necessary to reignite the arc constantly when the arc voltage crosses zero level. This occurs at a frequency of 100 Hz.

The interference noise has been suppressed by a combination of techniques involving filtering, grounding, isolation and shielding. Fibre-optic links and optoisolators are an essential part of the solution. The research has resulted in the production of robust TIG welding systems used by industry.
A review of quantitative feedback theory as a robust control system design technique
Authors: Azvine B. , Wynne R.J.
Published: November 2007

Performance robustness has been an important issue in control and it has been increasingly recognised as an area of significance in many design applications. This issue has particular importance among the engineering community because it offers a solution to control system design problems for plant and processes that cannot be described by a single linear time-invariant model. The aim of this paper is to describe one of the methods available for robust control system design called Quantitative Feedback Theory (QFT) and discuss its application to engineering problems. QFT is a powerful design technique based on multi degree-of-freedom use of feedback. The basic building block of a multi-degree-of-freedom system is a two-degree-of-freedom system in which two controllers are present, one inside the feedback loop, used to reduce closed-loop uncertainty, and the other prior to the loop, used to shape the input in order to achieve the required output. To show the power of the method, the application to an aero engine described by a non-linear model, linearised at five operating conditions, is discussed. A comparison of the QFT method is also made with the H-infinity method. It is shown that the H-infinity formulation of the QFT problem can produce a more conservative solution than the QFT method.
Modelling of continuous bioreactors via neural networks
Authors: Yang Y.Y. , Linkenst D.A.
Published: November 2007

This paper deals with the modelling of continuous bioreactors by neural networks. The detailed procedure of neural network modelling is given, along with comments on neural network topology, the training data set, and some key design parameters. Various simulations are carried out to study the feasibility of neural network modelling for this application. Simulation results obtained are satisfactory, concerning the modelling ability and noise rejection features of the neural network. It shows that the back-propagation neural network is a promising tool for bioreactor modelling.
A large-scale transputer network application: the aero-mechanical simulation of a single-rotor helicopter for control system design
Authors: Lawes S.T. , Clarke T.
Published: November 2007

The proposed role for future advanced rotorcraft requires superior agility and enhanced safety, coupled with a reduced pilot workload. More elaborate flight control systems will therefore be required which will have to be digitally implemented. New design methodologies will be required, in turn necessitating the development of new tools. One such tool will be a more complex real-time simulation of helicopter dynamics. This paper describes a generic real-time computer model of helicopter dynamics that eliminates the need for simplifying assumptions to enable real-time operation. A concurrent approach is used that exploits the natural parallelism of the helicopter dynamics. Implemented on a transputer network, the model exhibits ideal qualities as a development tool for advanced helicopters and their systems.
Object-oriented software design techniques for process control
Authors: Wright D.T. , Williams D.J.
Published: November 2007

This paper summarises research carried out under the above area, and examines the use of Object-Oriented (OO) design techniques and tools for the design of real-time manufacturing control systems. Such systems are likely to be applied in the manufacture of products in advanced materials. The project involves both research into the techniques and their application on real world problems. It considers systems to support the design of hybrid control systems to improve product yield and quality. Future work involving OO software development methodologies, qualitative modelling, rapid prototyping, and application of a number of control paradigms (including low-level PID, neural network and fuzzy logic) are discussed, with conclusions.
CAPNEX: an expert system for capnography (CO2 respiration analysis)
Authors: Ventzas D.E.
Published: November 2007

In this paper a capnograph expert system that performs patient medical diagnosis and instrument fault detection is implemented, based on clinical capnography data and experience. This is achieved through a computerised capnograph. Capnography technology is summarised and a preliminary evaluation of the expert system is made.
The effects of sampled signals on the flight control system of an agile combat aircraft with a flexible structure
Authors: Taylor Richard , Pratt Roger W. , Caldwell Brian D.
Published: November 2007

The introduction of digital flight control systems in modern aircraft has created an additional factor in the analysis and prevention of aeroservoelastic interactions. This paper focuses on the propagation of signals through an aeroservoelastic system incorporating a digital flight control system. It is shown that the digital system will increase the seriousness of the aeroservoelastic, effects due to aliasing. The contribution to the process of the zero-order-hold is explained, and additionally the possible consequences of high-frequency signals on the performance of the actuation system is examined. Finally, the paper offers general guidelines when designing filters for the attenuation of structural modes, including the significance of the phase, in the digital flight control system.
Road lane trajectory estimation using yaw rate gyroscopes for intelligent vehicle control
Authors: Barber P.A. , King P. , Richardson M.
Published: November 2007

Vehicles equipped with advanced control systems can benefit significantly from an accurate estimation of the trajectory of the road ahead. This can be used, for example, to determine whether an obstacle, detected by a forward-looking sensor, is on the vehicle's path or in an adjacent lane. One method of deriving such an estimate is to combine a measurement of the yaw motion of the vehicle with some basic assumptions about the nature of the road. An adaptive cruise control system, equipped with a yaw-rate-based trajectory estimation, was demonstrated by Jaguar Cars at the PROMETHEUS 'Board Members Meeting' in 1994 with control that could distinguish between vehicles in adjacent lanes, even on motorway bends.

This system showed a considerable benefit over those which did not make use of any steering information to select the sensor's field of interest, allowing the vehicle to follow traffic more naturally. The paper explores the consequences of the technique by modelling the nature of curves on motorway roads, the sources of noise on the yaw rate signal and the filtering used to form a reliable estimate of the road trajectory.
A systematic investigation on the use of force ratios in tool condition monitoring for turning operations
Authors: Bayramoglu M. , Dungel Ü.
Published: November 2007

One of the serious problems in automated chip-removal processes is the prediction of tool changing time. Tool change before the end of its useful time causes an increase in tool cost. Late changes, on the other hand, cause dimensional inaccuracies and surface finish deterioration on the workpieces and an increase in the energy consumption. Therefore, it is aimed in this work to present an in-depth study of the effects of cutting parameters on various force ratios and to determine their applicability for tool condition monitoring in turning processes.
The acquisition of word order in Dutch and German as L1 and L2
Authors: Jordens Peter
Published: November 2007

In a recent paper, Clahsen and Muysken (1986) argue that children acquiring German as their first language have access to the 'move alpha' matrix when constructing a grammar for German. This should explain why children have SOV base order and the rule of verb-fronting from the very beginning. In this paper, it is argued that children's OV utterances cannot be related trans formationally to VO utterances. Initially, children acquire OV and VO with different sets of verbs.

Clahsen and Muysken (1986) also claim that interlanguage rules of adult L2 learners are not definable in linguistic theory. Du Plessis et al. (1987) reply to this in arguing that the interlanguage rules of adults acquiring L2 German word order fall within the range of systems permitted by the Headedness parameter, the Proper Government parameter, and the Adjunction parameter. Therefore, these adult learners should have access to Universal Grammar (UG). It is argued here that it is not necessary to make this assumption. The L2-acquisition data can be easily accounted for within a simple model of L1-structural transfer.
Analysing the acquisition stages of negation in L2 German: support for UG in adult SLA
Authors: Tomaselli Alessandra , Schwartz Bonnie D.
Published: November 2007

This paper continues the debate concerning the availability of Universal Grammar (UG) to adult L2 acquirers. Specifically, an analysis of native (prodrop) Romance speakers' acquisition of negative placement in L2 German is provided. Contrary to Clahsen (1987; 1988a) and Clahsen and Muysken (1988), we argue that a UG-based analysis for the three stages of NEGplacement is not only possible but in fact provides independent support for UG-based analyses of the developmental sequence found in L1 Romance, L2 German Verb placement (duPlessis et al, 1987; Schwartz and Tomaselli, 1988). In particular, by combining (1) aspects of the L 1 grammar with (2) the independently needed changes in parameter values (characterizing principal differences between the L1 and L2 grammars), we arrive at a non- ad hoc account. We also show how the resolution of additional problems concerning the data of this same set of L2 acquirers naturally follows from the analysis argued for. Finally, some discussion comparing the two UG-based analyses of the verb-placement data (duPlessis et al.'s and Schwartz and Tomaselli's) is included.
On the issue of completeness in second language acquisition
Authors: Schachter Jacquelyn
Published: November 2007

The issue of completeness in adult second language acquisition is critical in the development of a theory of second language acquisition. Assuming the Chomskyan definition of core grammar as being those aspects of the language determined by the interaction of the innately specified Universal Grammar and the input to which the learner is exposed, we need to ask if it is possible for an adult learner of a second language to attain native-speaker competence in the core aspects of the grammar of the second language. This paper examines evidence for presence or absence of one principle of UG, Subjacency, in the grammars of groups of proficient nonnative speakers of English. There are three groups whose native languages - Korean, Chinese, Indonesian - differ from English with regard to Subjacency, Korean showing no evidence of it, Chinese and Indonesian showing partial evidence of it. There is one group whose native language, Dutch, shows the full range of Subjacency effects that English does. If all groups show the same Subjacency effects in English that native speakers do, then it must be the case UG is still available for adult second language learning and completeness in second language grammars is possible; if not, then completeness cannot be included as a possible characteristic of adult second language acquisition. Proficient nonnative university students with the above native languages were given grammaticality judgement tests on a set of sentences containing a variety of structures (islands) and Subjacency violations involving those structures. Analysis showed that though all groups were able to correctly judge grammatical sentences (containing islands) as grammatical, only the Dutch group was able to correctly judge ungrammatical sentences (containing Subjacency violations) as ungrammatical; the Korean subjects performed randomly on this task. This native language effect was shown not to be due to attribute variables, such as age of first exposure to English, number of months in an English-speaking country, number of years of English study, etc. The results support the conclusion that completeness is not a possible property of adult-acquired grammars since adults no longer have access to UG for the second language learning process.
Are C-tests valid measures for L2 vocabulary research?
Authors: Chapelle Carol A.
Published: November 2007

Second language (L2) researchers (Singleton and Little, 1991) have sug gested that C-tests, developed as norm-referenced measures for proficiency and placement testing (Klein-Braley, 1985), can be used in L2 vocabulary research. This article illustrates how researchers can bring to bear essentials of measurement theory on L2 research by weighing validity justifications pertaining to use of the C-test method for vocabulary assessment in L2 research. Validity is defined using the predominant framework from current measurement theory (Messick, 1989) and its relevance for L2 research is explained. The cornerstone of the definition is construct validity, which requires a definition of the construct to be measured - interlanguage vocabulary (i.e., vocabulary ability). A theoretical definition of vocabulary ability is presented and used to consider justifications for and against interpreting C-test performance as indicative of vocabulary ability. On the basis of evidence concerning construct validity and utility as well as the consequences of interpretations, the potentials and limitations of the C-test method for L2 vocabulary research are identified.
Semantics-syntax correspondences in second language acquisition
Authors: Juffs Alan
Published: November 2007

This article investigates knowledge of semantics-syntax correspondences in SLA within the Principles and Parameters framework. A parameter of semantic structure is used to investigate knowledge of two distinct, but underlyingly related, verb classes: change of state locatives and 'psychologi cal' verbs. Chinese and English contrast in terms of the parameter setting. Experimental evidence indicates that adult Chinese learners of English L2 initially transfer parameter settings, but are able to reset the parameter. However, they only acquire L2 lexical properties and concomitant syntactic privileges with ease when L2 input adds a representation to their grammar. When positive L2 input should pre-empt overgeneralizations based on rep resentation transferred from the L1, for some learners L1 influence persists until quite advanced stages of acquisition. The implications of the results for the parameter-setting model of SLA are discussed.
The nature of interlanguage: SLA of English reflexives
Authors: Wakabayashi Shigenori
Published: November 2007

This article examines experimental data of SLA of English reflexives. A carefully designed experiment to tap syntactic constraints of interlanguage grammar and the consideration of the consistency of responses of individual subjects reveal the systematicity of interlanguage grammar much more explicitly than previous studies. Of subjects' behaviour, 95% perfectly matches the sanctions of parameter values suggested in Wexler and Manzini's (1987) Governing Category Parameter and Proper Antecedent Parameter. However, re-examined in the light of the alternative hypotheses in the Binding Theory since Wexler and Manzini (1987), interlanguage grammar may violate the sanctions of Universal Grammar (UG) parameters for the variaton of referential properties of anaphors. Taking into account of this new evidence, the author suggests: 1) SLA is systematic; 2) L2 learners' interpretations of English reflexives are attributed to their linguistic knowledge; and 3) UG is available in SLA, and SLA of the referential properties of English reflexives is carried out by (re)setting parameter values.
A clinical evaluation of the performance characteristics of one membrane and five bubble oxygenators: gas transfer and gaseous microemboli production
Authors: Pearson Derek T , Holden Michael P , Poslad Stefan J , Murray Alan , Waterhouse Philip S
Published: November 2007

The gas transfer characteristics and gaseous microemboli (GME) production of five different bubble oxygenators (Polystan Venotherm, Harvey H-1700, Bentley BIO-10, Gambro 10 and Shiley S-100A HED) and one membrane oxygenator (Cobe CML) have been assessed during standardized clinical perfusion for open-heart surgery in 60 adult patients. The perfusionist attempted to maintain physiological levels of PaCO2(5 ± 1 kPa) and PaO2(12 ± 2 kPa). Only 3% of blood gas values were within the normal range in the Bentley BIO-10 group compared with 17% for the Gambro 10, 20% for the Shiley S-100A HED, 31% for the Polystan Venotherm, 33% for the Cobe CML and 36% for the Harvey H-1700. The number of GME detected in the arterial line was significantly lower in the Cobe CML membrane oxygenator when compared with any of the five different bubble oxygenators (p < 0·001). The Polystan Venotherm released significantly less GME (p < 0·02) than the other oxygenators and the Shiley S-100A HED released significantly more GME (p < 0·02) than the other oxygenators except the Gambro 10. Low gas-blood flow ratios were not necessarily associated with low GME levels and inadequate oxygenation. This study provides meaningful data on which to base the choice of oxygenator, for clinical perfusions.
Complement consumption during cardiopulmonary bypass: bubble versus membrane oxygenators
Authors: Mickleborough Lynda L , Arnold George , Chiu Ray C-J
Published: November 2007

The purpose of this study was to compare levels of C3 and C4 during cardiopulmonary bypass, using bubble and membrane oxygenators. In vitro studies were performed using human blood in a simple circuit involving an oxygenator, roller pump and connector tubing. In vivo studies were carried out in two separate institutions using a variety of bubble and membrane oxygenators. Samples were taken throughout the pump run (30-1 20 minutes). Complement levels were corrected for haemodilution. All oxygenators tested caused a rapid decrease in C3 and C4 complement levels on institution of bypass. The magnitude and timing of these decreases were similar in the membrane and bubble groups. Thereafter, complement levels were stable throughout the pump run. These data do not suggest that there is any difference in complement activation during relatively short pump runs using bubble and membrane oxygenators.
Oxygen transport and oxygen consumption vs. cardiac output at different haematocrits
Authors: Hill Esther P , Willford David C , Moores William Y , Bellamy Ronald , Heydorn William H
Published: November 2007

Oxygen consumption was measured in 10 anaesthetized, surgically instrumented domestic pigs on cardiopulmonary bypass while cardiac output (pump flow rate) was decreased. Oxygen consumption data (calculated by the Fick principle from blood flow rate and arterial and mixed venous content measurements) were plotted against total oxygen transport (TOT=QCaO2, where Q is pump flow rate and CaO2 is arterial blood oxygen content). Oxygen consumption (VO2) measurements were made in each animal at two haematocrits (approximately 30%, which is normal for pigs, and approximately 15%). In five of the animals (Group I) the measurements were made with normal haematocrit first, the blood was then haemodiluted with plasma or Dextran, and the measurements were repeated. In the remaining five animals (Group II), the haematocrit orderwas reversed. The plots showed two regions: above a certain value of TOT which we call critical TOT, VO2 was relatively independent of TOT, while at lower values of TOT, VO2 decreased approximately linearly with TOT. At the low haematocrit, the critical TOT (±S.E.M) was significantly lower ( P <0.05) than at normal haematocrit (6.9 ± 0.9 vs. 10.7 ± 1.2 ml/min/kg). Below the critical TOT, the curves for the two haematocrit levels were not significantly different. Above the critical TOT, the average VO2 was lower at the low haematocrit than at the normal haematocrit (6.0 ± 0.6 vs. 8.8 ± 1.1 ml/min/kg).
A new impeller blood pump design: in vitro and in vivo studies
Authors: Qian Kun-xi , Jin Yong-an , Lin Kuang-ding , Pi Kai-duan , Wang Yi-pin , Qing Fei
Published: November 2007

The most important design considerations in the development of a new centrifugal blood pump revolve around reductions in size and blood contact surface area, together with the production of physiological flow characteristics without undue trauma to blood proteins and formed elements. This report describes the functional testing of a centrifugal pump which weighs 240g (including a 190g motor), capable of generating a flow of 4I per minute against a pressure head of 100mmHg. Flow can be induced in both pulsatile and nonpulsatile modes.

In vitro testing was conducted by comparison with a locally manufactured roller pump (Shanghai) and a Sarns 7000 pump for nonpulsatile evaluation, whilst pulsatile tests made use of a locally manufactured diaphragm pump and a Polystan pulsatile pump. Haemolysis studies showed the centrifugal pump produced only 20% and 30% red cell damage compared with the Shanghai and Sarns roller pumps respectively and in the pulsatile mode it produced only 17% and 8% of the haemolysis created by the diaphragm and Polystan pumps respectively.

For in vivo testing the pump was used as an LVAD in dogs and goats and operated in both pulsatile and nonpulsatile flow modalities. Assisted flow was controlled at 40% to 50% of total flow and in nonpulsatile perfusions lasting up to 32 hours, and pulsatile perfusions lasting up to 21 hours, only very small changes were measured in haematological parameters.

This study indicates that small centrifugal pumps may offer considerable advantages over the more conventional diaphragm and roller pumps with respect to pumping efficiency and blood trauma, and that careful impeller design is central to achieving optimal pump characteristics.
Review article : Mechanical ventricular support in the management of postcardiotomy cardiogenic shock
Authors: Chalmers Jac , Graham TR
Published: November 2007

'For many reasons clinicians hesitate to employ mechanical devices of unproved efficacy except in the most critically ill patients and then only as a desperate measure. These approaches accounted for a substantial lag time between intra-aortic balloon pump availability and widespread utilization. Ventricular assist devices, recently approved for initial clinical trials, face the same dilemmas'. Norman, 1977.1
A positive/negative pressure monitor for use in neonatal extracorporeal membrane oxygenation
Authors: Snyder Edward J , Weckerly Sean , Gross Larry , Velez Melvin , Tackel Ira S
Published: November 2007

The following is a design for a simple, inexpensive combination positive/negative pressure monitor, with applications in neonatal extracorporeal membrane oxygenation (ECMO).

Negative (venous) pressure in the ECMO tubing circuit is monitored in the traditional reservoir volume-sensing manner, with a 5cc reservoir and associated sensing circuitry. Positive (arterial) pressure is measured by any manufacturer's blood pressure transducer/amplifier combination. The analogue signal relating to this pressure is routed from the amplifier to the ECMO pressure monitor for comparison to a reference value. If the positive pressure exceeds this reference value (indicating an overpressure situation) or the pillow collapses (indicating excess negative pressure), respective audible and visual alarms are activated and power to the blood (roller) pump is removed. When the alarm situation is remedied, power is automatically restored to the pump.

The ECMO pressure monitor affords great sensitivity, accuracy and dependability. It is adaptable to most roller pump driven ECMO systems and blood pressure monitors. The device can be assembled by a competent electronics technician, at an approximate parts cost of US$325.00.
Alpha-1-acidglycoprotein levels in infants during cardiopulmonary bypass and deep hypothermic circulatory arrest
Authors: Lönnqvist Per-Arne
Published: November 2007

Plasma levels of alpha-1-acidglycoprotein (AGP), the plasma protein primarily responsible for binding of a number of highly protein bound drugs (e.g. fentanyl, sufentanil, lidocaine, propranolol) that are frequently used during and/or immediately after cardiopulmonary bypass (CPB) with deep hypothermic circulatory arrest (DHCA), were investigated in six infants undergoing surgical repair of congenital heart disease. AGP levels dropped to 32% of control values (147mg/I ± 56 versus 458mg/l ± 83; p<0.0001 ) whereas albumin and total protein levels only decreased to 47% and 41 % of prebypass values respectively. This discrepancy could be explained by the addition of albumin containing solutions to the pump prime. Since protein binding of the above mentioned drugs will be significantly decreased, with a subsequent increase in the free pharmacologically active fraction of the drugs, caution is recommended when administering these drugs during or immediately after CPB/DHCA in order to avoid side effects and toxicity.
Successful treatment of acute postperfusion right ventricular failure by atrial septal defect creation
Authors: Raffa Hassan , Mohamed Taher Kayali  , Abdool Aniff Sorefan
Published: November 2007

A 14-year-old girl underwent primary total correction of tetralogy of Fallot (TOF). Acute intraoperative postperfusion right ventricular failure was encountered and all trials to wean the patient off cardiopulmonary bypass failed in spite of adequate pharmacological support. Survival was achieved, however, when an atrial septal defect was created and right ventricular decompression was thus established with a consequent increase of left atrial and left ventricular pressures and cardiac output.
Clinical evaluation of the Bentley Univox membrane oxygenator
Authors: Nowak J. , Pols G. , Brands W. , Rosseel P.
Published: November 2007

This paper reports a clinical evaluation of Bentley's new Univox membrane oxygenator (Bentley Laboratories, Irvine, California). In this new device, the blood flow path is outside the fibre, the incorporated heat exchanger consists of a 22-channel stainless-steel bellows, and the polypropylene fibres are woven into fibre ribbons and wound into each of the bellows channels. In this way, heat and gas transfers take place simultaneously. The priming volume has been reduced to 220ml and the membrane has an effective surface area of 1.6m2. A BMR 1900 collapsible reservoir (Bentley Laboratories, Irvine, California) was used as a venous reservoir. Ten consenting patients undergoing elective coronary artery bypass surgery were perfused with this new oxygenator. BSA was between 1.7 and 2.11 m 2; mean BSA was 1.81. Minimum priming was 1200ml. The blood-gas results were all within or close to the normal range used in our institution. Acid-base management was performed using alpha-stat regulation and no problems occurred in this series of patients. Average pO2 was 155mmHg±53 with a mean O2 transfer of 90.7ml and a maximum of 185ml. The heat exchange performance was very good, with a mean coefficient of heat exchange of 0.54±0.11 and a maximum of 0.87.
The effect of postoperative normovolaemic anaemia and autotransfusion on blood saving after internal mammary artery bypass surgery
Authors: Schönberger Jacques PAM , Everts Peter AM , Bredee Johan J , Jansen Evert , Goedkoop Rene , Bavinck Johan H , Berreklouw Eric , Wildevuur Charles RM
Published: November 2007

The efficacy of two blood conservation techniques in decreasing and in preventing the use of homologus blood products was retrospectively studied in 150 patients undergoing internal mammary artery bypass surgery. Patients were matched according to prebypass blood haemoglobin (Hb) content and body surface area and were allocated to one of three groups: in the patients of group 1 (n = 50), normovolaemic anaemia (NA) was accepted postoperatively (haematocrit [Hct] was accepted to a minimum level of 25%); the patients of group 2 (n = 50) were treated with postoperative autotransfusion (AT) of mediastinal shed blood and acceptance of NA. Group 3 (n = 50) contained control patients, not treated with NA or with AT (Hct was accepted to a minimum level of 30%).

Patients of group 1 required 3.0 ± 0.3 units of homologous blood products, but the patients of groups 2 and 3 received significantly more (p <0.01 ) units: 3.9 ± 0.2 and 4.5 ± 0.3 units. No donor blood products were needed in 36%, 9% and 5% of the patients in groups 1, 2 and 3 respectively. The net postoperative blood loss was similar in the groups: 1229 ± 92 ml in group 1, 1098 ± 74 ml in group 2 and 1243 ± 72 ml in group 3. However, total blood loss (1982 ± 135 ml), including the retransfused part (954 ± 89 ml), was significantly larger (p <0.01) in group 2, than in groups 1 and 3.

We conclude that NA alone is more effective than the combination of NA and AT of large amounts of shed blood in reducing and in preventing the need for homologous blood products in internal mammary artery bypass surgery. When AT of a large amount of shed blood is employed in addition to NA, increased bleeding is observed.
Do plasma catecholamines influence microcirculatory blood flow in cardiac surgery patients?
Authors: Boldt J. , Zickmann B. , Ballesteros M. , Herold CH , Dapper F. , Hempelmann G.
Published: November 2007

To investigate whether plasma catecholamines influence blood flow on the microcirculatory level, forehead and forearm skin blood flow was measured by a two-channel laser Doppler blood flux monitor in 50 patients undergoing aortocoronary bypass grafting. Macrohaemodynamics, plasma viscosity, and skin temperatures were additionally monitored. Plasma catecholamines (adrenaline [AD] and noradrenaline [NOR] ) were determined using high-pressure liquid chromatography (HPLC) from arterial blood samples.

In the prebypass period, blood concentrations of both catecholamines increased slightly showing a wide range of values (AD ranging from 3 to 955 pg/ml; NOR ranging from 27 to 5326 pg/ml). In spite of the tremendous increase in plasma catecholamines before and after bypass, laser Doppler flow (LDF) remained almost stable in this period. Neither LDF nor macrocirculatory parameters were correlated to plasma catecholamines. Cardiopulmonary bypass (CPB) resulted in a significant increase in catecholamines (AD ranging from 80 to 2480 pg/ml; NOR ranging from 188 to 9898 pg/ml). Although haematocrit and plasma viscosity were significantly reduced during CPB, LDF decreased in comparison to baseline values (LDF forehead: -25%; LDF forearm: -35%) ( p<0.05).

It is concluded that plasma catecholamine levels were markedly changed during cardiac surgery showing a wide range of concentrations. Microcirculatory flow assessed by laser Doppler remained almost unaffected by these alterations and was not correlated to AD or NOR plasma concentrations. However, during CPB a significant increase in catecholamines can contribute to the risk of microperfusion abnormalities which can be assessed by laser Doppler technique.