bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption of Some Textile Dyes onto Crosslinked Poly(N-Vinylpyrrolidone)
Authors: Ekici Sema , Işıkver Yasemin , Şahiner Nurettin , Saraydın Dursun
Published: February 2004

The adsorption of some textile dyes such as Indigosol Blau IBC, Iyozol Turkish G, Iyozol Black B, Remazol Brilliant Orange 3R, Remazol Brilliant Violet 5R, Remazol Blau 3R, Sumufix Red 3BF and Everzol Yellow 4GL with crosslinked polyvinylpyrrolidone) was investigated. Adsorption of these textile dyes onto crosslinked polyvinylpyrrolidone) was studied by batch adsorption techniques at 25°C. The adsorption isotherms obtained were L-type (Langmuir-type) according to the Giles classification system. Adsorption studies indicated that monolayer coverage of the crosslinked poly-( N-vinylpyrrolidone) by the dyes studied increased in the order: Indigosol Blau IBC > Iyozol Turkish G > Sumufix Red 3BF > Iyozol Black B > Remazol Brilliant Orange 3R > Remazol Blau 3R > Everzol Yellow 4GL > Remazol Brilliant Violet 5R. Values of the removal efficiency of the dyes ranged from 21% to 81%.
Theoretical Description of Adsorption from Binary Liquid Non-Electrolyte Solutions with Unlimited Component Miscibility on to Microporous Solids
Authors: Ziółkowska Dorota
Published: February 2004

The ‘solution’ analogues of four single-gas adsorption isotherms [i.e. the Langmuir-Freundlich (LF), the generalized Langmuir (GL), the Toth (T) and the LF-GL equations] were examined. The derived expressions were applied to the description of the experimental adsorption data relating to the sorption of a binary liquid solution containing components of unlimited miscibility on to microporous solids. Optimization of the equation parameters, as well as a comparison of the results obtained with those determined earlier for sorption in systems where the components were of limited miscibility, was undertaken.
Preparation of Activated Carbons from Cork by Physical Activation in Carbon Dioxide
Authors: Carrott P.J.M. , Carrott M.M.L. Ribeiro , Mourão P.A.M. , Lima R.P.
Published: February 2004

Activated carbons (ACs) were prepared by the physical activation of cork wood, virgin cork and adult cork of different particle sizes in carbon dioxide and characterised by elemental analysis, DRIFTS, SEM and N2 adsorption at −196°C. The wood gave results similar to those obtained with other lignocellulosic precursors. On the other hand, the cork, which has a different chemical composition as well as microstructure, gave somewhat unusual results. The cork ACs retained the characteristic honeycomb structure of the precursors and had low C/O ratios with oxygen present in the form of basic carbonyl and ether groups. With increasing activation, the micropore volume approached a limiting value of ca. 0.33 cm3/g, while the mean pore width was in the range 0.8–1.1 nm and decreased slightly with increasing burn-off. It was also found that the rate of activation of the adult cork was more than 10-times faster than that of the wood or the virgin cork.
Characterization of the Structural and Gas Adsorption Properties of ETS-10 Molecular Sieve
Authors: Bagnasco Giovanni , Turco Maria , Busca Guido , Armaroli Tiziana , Nastro Alfonso , De Luca Pierantonio
Published: February 2004

A sample of ETS-10 was prepared and characterized by spectroscopic (Raman, UV–vis, FT-IR) and TPD techniques. An interpretation of the vibrational spectra was proposed. Absorption in the UV–vis range was typical of charge-transfer transitions involving octahedral Ti. No surface –OH groups were detected on the dehydrated sample. FT-IR measurements showed that water was adsorbed in two different molecular modes while ammonia was adsorbed coordinatively and mostly desorbed below 600 K. These results were confirmed by TPD studies that showed hydrogen-bonded water and water coordinated to Na+ and K+ cations located in the main channels of ETS-10. Ammonia TPD measurements on the hydrated material provided evidence for two forms of adsorbed NH3, both bonded to water molecules. On the anhydrous material, NH3 was probably coordinated only to the more loosely bonded Na+ and K+ ions in the main channels of ETS-10. The amount of adsorbed NH3 was markedly reduced after heat treatment that led to a partial loss of crystallinity.
Wind Shear Extremes at Possible Offshore Wind Turbine Locations
Authors: Hansen Kurt S. , Larsen Gunner Chr.
Published: February 2004

Positive and negative short-term extreme wind shear distributions (conditioned on the mean wind speed) are determined and compared for a number of offshore sites. The analysis is based on rapidly sampled field measurements (1–8 Hz) extracted from the “Database on Wind Characteristics” ( www.winddata.com ).

Three different averaging periods (2, 5 and 10 seconds) are considered, and for each averaging period a relation between the resulting extreme shear distributions and the averaging time are presented. The short-term extreme shear analysis is based on different spatial distances, and extrapolation to a spatial distance of 100 m has been investigated. Such distances are appropriate for the next generation of offshore wind turbines.

The paper concludes with an estimation of the short-term extreme shear values, which are compared to the values specified in the IEC-61400 code. The extreme IEC shear values seems to be rather conservative for an offshore location, compared to the estimated values based on measurements.
Performance Decay Analysis of New Rotor Blade Profiles for Wind Turbines Operating in Offshore Environments
Authors: Arrighetti Cinzio , De Pratti Giovanni Maria , Ruscitti Raffaele
Published: February 2004

Wind turbine installations at near-shore and off-shore sites focuses attention on the operating conditions in very aggressive environments, characterized by the presence of sand, dust and saline moisture in the air stream. The environment causes rotor blade erosion of the leading edge, thinning of the trailing edge and roughness increase all over the rotor blade surface; these effects produce severe performance decay, as lift reduces and drag increases. Test analysis has been performed, with a water-table test-bench at “La Sapienza” University of Rome, on the performances of some new profiles, designed for wind turbine rotor blade applications. The results are compared with literature and previous experimental measures.
A New Technique to Reduce Vibration in Lightweight Floors
Authors: Ljunggren Fredrik
Published: February 2004

Lightweight floor constructions often suffer from annoying vibration. Long span floor are especially vulnerable with dynamic properties that yield both springiness due to low stiffness and resonant vibration due to poor damping. A new method, that treats resonant vibration, applicable to floors with resilient ceiling, is presented in this study. By using a piece of strategically located visco-elastic material connected to the ceiling joists, which is designed using a finite element model for an optimal position and size, it is demonstrated that the damping of the floor is increased. The results show that the damper is extremely efficient to reduce vibration of the type where floor and ceiling are oscillating out of phase to each other. The device also affects in phase modes like the fundamental one, but to a lower extent.
Aspects of Urban Noise Pollution in a Large Brazilian City
Authors: Henrique Paulo , Zannin Trombetta
Published: February 2004

This paper presents the results obtained in a study on environmental noise pollution in the city of Curitiba, Brazil. The equivalent sound level values - LA,eq,2hr - were measured and tabulated for 1000 locations spread over the urban zones of the city of Curitiba. It was found that 93.3% out of the locations display, during the day, equivalent sound levels over 65 dB(A), and 40.3% out of the locations measured display during the day extremely high values of equivalent sound levels: over 75 dB(A). Measurement points were evaluated according to the assumptions established by two types of legislation: 1) local legislation: Law 8583 of 1995, which deals with urban noise and public comfort; 2) international legislation: the criteria of the US Department of Housing and Urban Development - HUD.
Measurement Uncertainties for Sound Field Levels in Rooms
Authors: Weise Wieland
Published: February 2004

Within the scope of quality management, the determination of measurement uncertainties is increasingly gaining importance. In this context the ‘Guide to the Expression of Uncertainty in Measurement’(GUM) provides the physical and mathematical concept and fundamentals. It can be applied to all physical measurements. However, in measurements of pressure levels in sound fields in room or building acoustics, the relative uncertainties can be very large. The question is what implications this has for the calculation of uncertainties. The basic ideas of the GUM will be outlined and then applied to different modeled sound fields. The results obtained with the linearised model usually used will be compared to exact results.
A Review of Research on Environmental Noise Barriers
Authors: Ekici Inan , Bougdah Hocine
Published: February 2004

During the past four decades, extensive research has been carried out on different noise barrier shapes using analytical and physical modelling as well as full scale testing. This paper reviews traffic noise barrier research and its findings to date. It provides a catalogue of noise barrier profiles; identifying the relative acoustic benefits of each and the physical principles on which they operate. The likely effects of ground and atmospheric conditions on their absolute acoustic performance are described. The types of barriers which are commonly used in practice and those deserving further attention are highlighted. Based on the findings of previous work, recommendations are made on possible areas of further research.
Contribution of Sound Radiation from Building Structures by Multiple Input-Single Output Model Analyses
Authors: Kobayashi Masahito , Kamiakito Noboru , Shioda Masazumi , Yamashita Yasuhiro
Published: February 2004

The influence of the sound radiation from surfaces is examined from a prediction of structure-borne sound. The level of structure-borne sound due to environmental ground vibration is shown from a Multiple Coherent Output Spectrum, which represents common elements of all input vibration signals. The use of the Multiple Coherent Output Divided Spectrum at each surface is examined. A parameter is proposed which shows the contribution of structure-borne sound from the each surface of the room. The theory is considered for a system consisting of six speakers equivalent to the six surfaces of the room, and prediction compared with experimental results.
Technical Note: Impact Sound Reduction for Cross-Linked and Non-Cross-Linked Polyethylene Foams in Suspended Concrete Floor Structures
Authors: Díez-Gutiérrez S. , Rodríguez-Pérez M.A. , Machimbarrena M. , González J. , de Saja J.A.
Published: February 2004

The acoustic behaviour of two building systems, a traditional concrete structure and an innovative one involving expanded polystyrene (EPS) elements have been compared using field measurements. The results indicate that the airborne sound insulation is very similar for both construction methods, whereas impact sound insulation is better for the innovative system.

The improvement obtained by introducing polyethylene foams in floating floor constructions has also been investigated for the EPS system using field measurements. Also, the impact sound insulation improvement obtained with two different polyethylene foams has also been analysed by performing laboratory experiments. Whilst both materials are adequate for this application, results indicate that the non cross-linked foam has a better performance.
A General Theory for Flexural-Torsional Buckling of Thin-Walled Members II: Fictitious Load Method
Authors: Tong Gengshu , Zhang Lei
Published: February 2004

There exist two different theories on the flexural-torsional instability of the thin-walled members, and based on them, very different results for beam elastic buckling can be obtained. In this paper, a new theory was presented to solve the inconsistency between the two different theories noted above after very deep investigation. In this new theory, the transverse stress was introduced as an important factor for member stability, in addition to the longitudinal and shear stresses and strains already considered in the work of others. A fictitious load method is used to derive the general theory in this paper. The fictitious loads are determined based on plate buckling theory, revised to take account of the overall flexural buckling of the members.
Personal Property Security Law Reform in Comparative Perspective—Antipodean Insights?
Authors: McCormack Gerard
Published: February 2004

This paper addresses the issue of personal property security law reform. It asks why the reform agenda has been pursued much more vigorously in New Zealand than in England even though the two jurisdictions have had very similar starting points. In addition, the paper looks at the fundamental and difficult policy questions that have to be considered in personal property security law reform and the importance of attention to detail in enacting reform measures. If England is to have successful personal property security law reform, then the paper suggests that some of the precedents set in New Zealand may have to be avoided.
The Law in Undercover Policing: A Comparative Study of Entrapment and Covert Interviewing in Australia, Canada and Europe
Authors: Bronitt Simon
Published: February 2004

This article explores from a comparative perspective some of the legal, evidential and procedural issues raised by undercover policing. It focuses on two of the more common, yet legally problematic, techniques of covert investigation: namely, entrapment and covert interviewing. The comparison draws on legal developments in Australia, Canada and Europe.
Small Firms and Their Difficulties with Contractual Relationships: Implications for Legal Policy
Authors: Lewis P.
Published: February 2004

This paper is based on interviews with and documents supplied by the owners, directors and managers of 40 small businesses in the UK. It analyses the contractual arrangements made for business purposes, investigates the firms' experiences of litigation and attempts to classify the legal problems faced by small firms in their contractual relationships.

The firms' legal problems were more in the area of private business relations than public administration and many of the actions arising out of contractual relations were statutory rather than contractual. The most common type of problem related to firms' inadequate response to the legal environment rather than to deficiencies in the law or legal system. There was only a limited professional legal input into contract formation although the use of standard terms was widespread. There were doubts on the part of some of the firms about whether the contractual framework they had adopted offered sufficient legal protection.

It is submitted that it is right that small firms should not be excluded from legal duties placed upon employers more generally but the conclusion here is that they are badly placed to fulfil these duties because of a difficulty in gaining access to legal resources. The main implication for legal policy is that small firms may require a publicly-subsidized legal service if they are to conduct their contractual relationships lawfully, particularly as these relationships come to be regulated increasingly by statute. It is noted that some steps consistent with such an approach are being considered by the government in relation to employment law.
A Critical Review of English Law in Respect of Criminalising Blameworthy Behaviour by HIV+ Individuals
Authors: Warburton Damian
Published: February 2004

The spread of some illnesses between people is almost inevitable and in many circumstances it would be ludicrous to propose attaching any criminal liability. However, in the case of HIV, where successful transmission eventually causes the death of its host, and transmission methods are well known, to grant impunity to those carrying this responsibility is a difficult thing to accept.

This article is an examination of the status of English law as it presently stands, where not only are remedies for assault still rooted in Victorian legislation, but also where, crucially, a case decided under Victorian morality has dogged this area of law ever since.

At the eleventh hour of writing, the decision in R v Dica has turned the whole discussion upside down; and then there is the question of whether English law actually needs an HIV-specific statute.
The Definition of Oblique Intention
Authors: Kugler Itzhak
Published: February 2004

The Law Commission contended that a person should not be held as having oblique intention with respect to a result if his whole purpose in acting is to avoid this result. This article asserts that the Commission was wrong concerning this point. The justifications that it gave for the rule it suggested are not convincing, while the rationales for the doctrine of oblique intention apply even to cases in which the whole purpose of the actor, in acting, is to avoid the proscribed result.
Contributory Factors and the Situation of Children during Incidents of Domestic Violence: A Snapshot
Authors: Mason Mark
Published: February 2004

Research suggests that alcohol is an important contributory factor in incidents of domestic violence. Children living in households where incidents of domestic violence take place are at immediate risk of physical and psychological harm. This study aims to discover what factors most frequently contributed to incidents of domestic violence and what proportion of these incidents involved children in some way, and by doing so assesses the size and nature of the problems in this area. This report draws on information about victims and incidents from 2,596 police incident forms between April 1999 and March 2000. Alcohol was judged to have been the major contributory factor leading to incidents of domestic violence, it having been implicated in 30% of all incidents, while children were disproportionately more likely actually to have been ‘involved’ in an incident when alcohol or illicit drugs were judged to have been a contributory factor compared to others. The report discusses the implications of these findings.
Police Recruits' Training and the Socialisation Process: From the Network Perspective
Authors: Sato Miki
Published: February 2004

Police recruits learn police culture through the process of organisational socialisation. However, in New South Wales, since a Royal Commission inquiry into corruption in the police organisation in the mid-1990s, the organisational environment including police culture has become more complex and contingent. Under such a condition, recruits have been facing socialisation problems caused not only by shock at the gap between pre-entry expectation and reality but also by the diversity and shift of police culture. This article explores a recruit-friendly training method employing organisational network theory to improve socialisation problems. Network theory suggests that developing information networks and friendship networks contributes to an increase in organisational commitment, through which police recruits can socialise with the police organisation as a whole more smoothly.
Police Cynicism: Police Survival Tool?
Authors: Caplan Joel
Published: February 2004

This article broadly defines cynicism as a pessimistic and suspicious outlook on the part of police officers towards their job, the public and society as a whole. Cynicism is an evolving characteristic of even the most idealistic police recruits. Since it appears to be inevitable, should it be considered an unpleasant epidemic and condemned, or should it be respected and embraced as a necessary police survival skill? Through comprehensive research and the author's self-analysis of journal entries made when he worked as a police officer, this article seeks to understand why police become cynical. Then it looks at the effects of cynicism on the police personality and police–community relations. While cynicism has negative side-effects for police personnel, its positive role in police work cannot be overlooked. The public expects a proactive, crime-fighting police force. For this reason, cynicism can be a valuable tool for the police.
Victim-Centred Policing: The Shepherd's Solution to Policing in the 21st Century
Authors: Clark Mark
Published: February 2004

The article discusses the emergence of victim-centred policing as a philosophical approach to reducing the effects of criminal victimisation. It discusses the convergence of criminological thought with policing in identifying the importance of the victim in the response to crime. It identifies the need to restructure policing practices to position the victim as a strategic focus for policing in the twenty-first century and to take the institutional lead in the criminal justice system.

The symbolic, cultural and philosophical transformation necessary to operationalise the philosophy of victim-centred policing is examined. The importance of social research and the need for professional expertise within the policing unit to facilitate victim-centred police operations is also discussed.

The article explores the role of the victim in traditional law enforcement and the move towards models of community policing that emphasise victim involvement in the criminal justice system. A discussion of the victimisation process and the inclusion of principles of restorative justice as a critical factor in the recovery of the victim are provided.
Preparation and Characterization of New WHO Reference Reagents for Human Chorionic Gonadotropin and Metabolites
Authors: Birken Steven , Berger Peter , Bidart Jean-Michel , Weber Matthias , Bristow Adrian , Norman Rob , Sturgeon Catharine , Stenman Ulf-Håkan
Published: February 2004

Background: The currently used standards for human chorionic gonadotropin (hCG) and its α and β subunits (hCGα and hCGβ) contain substantial amounts of contaminating variants of hCG and other impurities. Furthermore, some partially degraded forms of hCG and its subunits have become of potential clinical importance, e.g., “nicked” forms of hCG (hCGn) and hCGβ (hCGβn), which contain cuts in the peptide backbone between amino acids 44–45 or 47–48 in hCGβ, and a fragment of hCGβ (hCGβcf) consisting of amino acids 6–40 and 55–92 bound together by disulfide bridges. The IFCC appointed a working group with the aim of preparing new standards for hCG and related substances to improve standardization of their immunoassays.

Methods: Large amounts of hCG and its subunits as well as of hCGn, hCGβn, and hCGβcf were prepared by previously developed purification methods in combination with hydrophobic interaction chromatography and reversed-phase HPLC. Each preparation was characterized on the basis of amino acid and sequence analyses, carbohydrate composition, and electrophoretic patterns. Immunoassays for relevant contaminating proteins were also performed.

Results: The major preparations were homogeneous and free of contaminating proteins. Concentrations of the final preparations were determined by amino acid analysis.

Conclusions: Calibrated in substance concentrations (mol/L) based on amino acid analyses, these preparations will facilitate improved standardization of immunoassays for hCG and its metabolites. The six preparations have now been established by the WHO as new 1st Reference Reagents for immunoassays with the following codes: hCG 99/688, hCGβ 99/650, hCGα 99/720, hCGn 99/642, hCGβn 99/692, and hCGβcf 99/708. In contrast to the 3rd International Standard (75/537), the clinically most important Reference Reagent for hCG (99/688) contains no hCGn and negligible amounts of free subunits.
LOINC, a Universal Standard for Identifying Laboratory Observations: A 5-Year Update
Authors: McDonald Clement J , Huff Stanley M , Suico Jeffrey G , Hill Gilbert , Leavelle Dennis , Aller Raymond , Forrey Arden , Mercer Kathy , DeMoor Georges , Hook John , Williams Warren , Case James , Maloney Pat ,   for the Laboratory LOINC Developers
Published: February 2004

The Logical Observation Identifier Names and Codes (LOINC®) database provides a universal code system for reporting laboratory and other clinical observations. Its purpose is to identify observations in electronic messages such as Health Level Seven (HL7) observation messages, so that when hospitals, health maintenance organizations, pharmaceutical manufacturers, researchers, and public health departments receive such messages from multiple sources, they can automatically file the results in the right slots of their medical records, research, and/or public health systems. For each observation, the database includes a code (of which 25 000 are laboratory test observations), a long formal name, a “short” 30-character name, and synonyms. The database comes with a mapping program called Regenstrief LOINC Mapping Assistant (RELMATM) to assist the mapping of local test codes to LOINC codes and to facilitate browsing of the LOINC results. Both LOINC and RELMA are available at no cost from http://www.regenstrief.org/loinc/. The LOINC medical database carries records for >30 000 different observations. LOINC codes are being used by large reference laboratories and federal agencies, e.g., the CDC and the Department of Veterans Affairs, and are part of the Health Insurance Portability and Accountability Act (HIPAA) attachment proposal. Internationally, they have been adopted in Switzerland, Hong Kong, Australia, and Canada, and by the German national standards organization, the Deutsches Instituts für Normung. Laboratories should include LOINC codes in their outbound HL7 messages so that clinical and research clients can easily integrate these results into their clinical and research repositories. Laboratories should also encourage instrument vendors to deliver LOINC codes in their instrument outputs and demand LOINC codes in HL7 messages they get from reference laboratories to avoid the need to lump so many referral tests under the “send out lab” code.
William Prout: Early 19th Century Physician-Chemist
Authors: Rosenfeld Louis
Published: February 2004

In the early 19th century, the discoveries of new substances in the healthy and diseased body spawned a search for chemical explanations for physiologic phenomena to guide medical diagnosis and control therapy. William Prout’s work on the nature and treatment of diseases of the urinary organs established his reputation as one of Britain’s most distinguished physiological chemists. Prout was very skeptical of chemical remedies because of possible side effects, but he suggested iodine treatment for goiter. He emphasized that a satisfactory diet should include carbohydrates, fats, protein, and water. In 1824, he showed that the acid of the gastric juice was hydrochloric acid. Prout applied chemical methods and reasoning to physiology and was criticized for his view that the body’s vital functions could be explained by chemistry. His remedy for lack of progress in animal chemistry was for physiologists to become chemists. Prout stimulated much discussion on atomic theory by his hypothesis that the atomic weights of all chemical elements are whole-number multiples of the atomic weight of hydrogen and that the chemical elements were condensed from hydrogen atoms.
Clinical and Analytical Performance of the Liaison Cardiac Troponin I Assay in Unstable Coronary Artery Disease, and the Impact of Age on the Definition of Reference Limits. A FRISC-II Substudy
Authors: Venge Per , Johnston Nina , Lagerqvist Bo , Wallentin Lars , Lindahl Bertil ,   the FRISC-II Study Group
Published: February 2004

Background: Measurements of cardiac troponins are currently used as the standard for the detection of myocardial injury. None of the current assays complies with the new requirements on assay imprecision as proposed by the European Society of Cardiology/American College of Cardiology. Our aim was to evaluate the clinical and analytical performance of the Liaison cardiac troponin I (cTnI) assay.

Methods:EDTA-plasma was used, and cardiac troponins were assayed with the first-generation AxSYM assay, the second-generation AccuTnI assay, the third-generation Elecsys assay, and the first-generation Liaison assay.

Results: In a 6-day imprecision study, the Liaison cTnI assay had mean CV ≤10% at 0.027 μg/L and ≤20% at 0.015 μg/L. The 99th percentile of the upper reference limit (URL) of a reference population was 0.041 μg/L (age range, 41–76 years). Individuals <60 years had a significantly (P = 0.001) lower 99th percentile, 0.022 μg/L. The FRISC-II study participants with cTnI ≥0.041 μg/L had a poorer outcome relating to death/acute myocardial infarction than those with cTnI <0.041 μg/L (P <0.001). Treatment with low-molecular-weight heparin (dalteparin) or an invasive strategy reduced cardiac events only in patients with concentrations >0.041 μg/L (P = 0.002 and 0.02, respectively). Comparison with the AccuTnI assay showed that a large cohort of the patients with poor prognosis was identified by the AccuTnI assay but not by the Liaison cTnI assay.

Conclusion: The Liaison cTnI assay is a sensitive assay with a CV ≤10% at the 99th percentile URL. The ability to detect age-related differences among apparently healthy individuals is unique among today’s commercial assays. The results indicate that different assays seem to identify different patient cohorts for cardiac risk in the lower range of cTnI concentrations.
Ion Suppression in Mass Spectrometry
Authors: Annesley Thomas M
Published: February 2004

Background: Mass spectrometry (MS) is being introduced into a large number of clinical laboratories. It provides specificity because of its ability to monitor selected mass ions, sensitivity because of the enhanced signal-to-noise ratio, and speed because it can help avoid the need for intensive sample cleanup and long analysis times. However, MS is not without problems related to interference, especially through ion suppression effects. Ion suppression results from the presence of less volatile compounds that can change the efficiency of droplet formation or droplet evaporation, which in turn affects the amount of charged ion in the gas phase that ultimately reaches the detector.

Content: This review discusses materials shown to cause ion suppression, including salts, ion-pairing agents, endogenous compounds, drugs, metabolites, and proteins. Experimental protocols for examining ion suppression, which should include, at a minimum, signal recovery studies using specimen extracts with added analyte, are also discussed, and a more comprehensive approach is presented that uses postcolumn infusion of the analyte to evaluate protracted ionization effects. Finally, this review presents options for minimizing or correcting ion suppression, which include enhanced specimen cleanup, chromatographic changes, reagent modifications, and effective internal standardization.

Summary: Whenever mass spectrometric assays are developed, ion suppression studies should be performed using expected physiologic concentrations of the analyte under investigation.
Frequency, Risk Factors, and Outcome of Hyperlactatemia in HIV-positive Persons: Implications for the Management of Treated Patients
Authors: Marceau Geoffroy , Sapin Vincent , Jacomet Christine , Ughetto Sylvie , Cormerais Louis , Regagnon Christel , Dastugue Bernard , Peigue-Lafeuille Hélène , Beytout Jean , Laurichesse Henri
Published: February 2004

Background: The nucleoside reverse transcriptase inhibitors used for the treatment of HIV-positive persons are now clearly associated with metabolic disorders. We determined the prevalence of and risk factors for hyperlactatemia in HIV-positive persons to assess the relevance of lactate venous blood concentrations during antiretroviral therapy.

Methods: We conducted a prospective cross-sectional study of venous lactate determinations with 282 consecutive HIV-positive persons who, in addition to a physical examination, had blood samples taken every 3–4 months for routine biochemical, immunologic, and viral assessment. The frequencies of hyperlactatemia and lactic acidosis were determined, and the risk factors were analyzed by a multivariate logistic regression model. The effect of modification of antiretroviral therapy in patients with moderate hyperlactatemia was also assessed.

Results: From 782 blood lactate determinations, we identified 65 (23%) patients with moderate hyperlactatemia and 5 (1.8%) with lactate concentrations >5 mmol/L (2 with severe lactic acidosis; 0.7%). Older age, drug regimens containing stavudine [adjusted odds ratio (OR) = 2.5] or a combination of stavudine-didanosine (adjusted OR = 3.1), and the use of buprenorphine (adjusted OR = 14.7) were independent predictors of hyperlactatemia. Among 65 patients with moderate hyperlactatemia, 39 did not have their treatments changed, and 26 had a new combination therapy that was associated with a clinical improvement and a more pronounced decrease in lactate (−1.66 vs −0.99 mmol/L; P <0.05).

Conclusions: Chronic compensated and moderate hyperlactatemia was common in our population study. Measurement of lactate, under standardized conditions, may be useful in optimizing management of HIV-positive persons on antiretroviral therapy.
Numeric Definition of the Clinical Performance of the Nested Reverse Transcription-PCR for Detection of Hematogenous Epithelial Cells and Correction for Specific mRNA of Non-Target Cell Origin as Evaluated for Prostate Cancer Cells
Authors: Schamhart Denis , Swinnen Johannes , Kurth Karl-Heinz , Westerhof Alex , Kusters Ron , Borchers Holger , Sternberg Cora
Published: February 2004

Background: Inappropriate quality management of reverse transcription-PCR (RT-PCR) assays for the detection of blood-borne prostate cancer (PCa) cells hampers clinical conclusions. Improvement of the RT-PCR methodology for prostate-specific antigen (PSA) mRNA should focus on an appropriate numeric definition of the performance of the assay and correction for PSA mRNA that is not associated with PCa cells.

Methods and Results: Repeated (RT-)PCR tests for PSA mRNA in single blood specimens from PCa patients and PCa-free controls, performed by four international institutions, showed a large percentage (≈50%) of divergent test results. The best estimates of the mean, λ (SD), of the expected Poisson frequency distributions of the number of positive tests among five replicate assays of samples from PCa-free individuals were 1.0 (0.2) for 2 × 35 PCR cycles and 0.2 (0.1) for 2 × 25 PCR cycles. Assessment of the numeric value of the mean can be considered as a new indicator of the performance of a RT-PCR assay for PSA mRNA under clinical conditions. Moreover, it determines the required number of positive test repetitions to differentiate between true and false positives for circulating prostate cells. At a predefined diagnostic specificity of ≥98%, repeated PCRs with λ of either 1.0 or 0.2 require, respectively, more than three or more than one positive tests to support the conclusion that PSA mRNA-containing cells are present.

Conclusions: Repeated nested PCR tests for PSA and appropriate handling of the data allow numeric quantification of the performance of the assay and differentiation between analytical false and true positives at a predefined accuracy. This new approach may contribute to introduction of PSA RT-PCR assays in clinical practice.
Neuronal Activity and Adenylyl Cyclase in Environment-Dependent Plasticity of Axonal Outgrowth inDrosophila
Authors: Zhong Yi , Wu Chun-Fang
Published: February 2004

The development of the nervous system is influenced by environmental factors. Among all environmental factors, temperature belongs to a unique category. Besides activating some specific sensory pathways, it exerts nonspecific, pervasive effects directly on the entire nervous system, especially in exothermic species. This study uses mutants to genetically discover how temperature affects nerve terminal arborization at larval neuromuscular junctions ofDrosophila. It is known that hyperexcitability in K+channel mutants leads to enhanced ramification of larval nerve terminals. Elevated cAMP levels induncemutants with reduced phosphodiesterase activity also cause enhanced arborization. These genetic alterations are thought to perturb mechanisms relevant to activity-dependent neural plasticity, in which neuronal activity activates the cAMP pathway, and consequently affect nerve terminal arborization by regulating expression of adhesion molecules. Here we demonstrate the robust influence of rearing temperature on motor nerve terminal arborization. Analysis of ion channel and cAMP pathway mutants indicates that this temperature-dependent plasticity is mediated via neuronal activity changes linked to mechanisms controlled by therutabaga-encoded adenylyl cyclase.
Nonopioid Actions of Intrathecal Dynorphin Evoke Spinal Excitatory Amino Acid and Prostaglandin E2Release Mediated by Cyclooxygenase-1 and -2
Authors: Koetzner Lee , Hua Xiao-Ying , Lai Josephine , Porreca Frank , Yaksh Tony
Published: February 2004

Spinal dynorphin is hypothesized to contribute to the hyperalgesia that follows tissue and nerve injury or sustained morphine exposure. We considered that these dynorphin actions are mediated by a cascade involving the spinal release of excitatory amino acids and prostaglandins. Unanesthetized rats with lumbar intrathecal injection and loop dialysis probes received intrathecal NMDA, dynorphin A(1-17), or dynorphin A(2-17). These agents elicited an acute release of glutamate, aspartate, and taurine but not serine. The dynorphin peptides and NMDA also elicited a long-lasting spinal release of prostaglandin E2. Prostaglandin release evoked by dynorphin A(2-17)or NMDA was blocked by the NMDA antagonist amino-5-phosphonovalerate as well the cyclooxygenase (COX) inhibitor ibuprofen. To identify the COX isozyme contributing to this release, SC 58236, a COX-2 inhibitor, was given and found to reduce prostaglandin E2release evoked by either agent. Unexpectedly, the COX-1 inhibitor SC 58560 also reduced dynorphin A(2-17)-induced, but not NMDA-induced, release of prostaglandin E2. These findings reveal a novel mechanism by which elevated levels of spinal dynorphin seen in pathological conditions may produce hyperalgesia through the release of excitatory amino acids and in part by the activation of a constitutive spinal COX-1 and -2 cascade.
Differential Localization of Glutamate Receptor Subunits at theDrosophilaNeuromuscular Junction
Authors: Marrus Scott B. , Portman Scott L. , Allen Marcus J. , Moffat Kevin G. , DiAntonio Aaron
Published: February 2004

The subunit composition of postsynaptic neurotransmitter receptors is a key determinant of synaptic physiology. Two glutamate receptor subunits,Drosophilaglutamate receptor IIA (DGluRIIA) and DGluRIIB, are expressed at theDrosophilaneuromuscular junction and are redundant for viability, yet differ in their physiological properties. We now identify a third glutamate receptor subunit at theDrosophilaneuromuscular junction, DGluRIII, which is essential for viability. DGluRIII is required for the synaptic localization of DGluRIIA and DGluRIIB and for synaptic transmission. Either DGluRIIA or DGluRIIB, but not both, is required for the synaptic localization of DGluRIII. DGluRIIA and DGluRIIB compete with each other for access to DGluRIII and subsequent localization to the synapse. These results are consistent with a model of a multimeric receptor in which DGluRIII is an essential component. At single postsynaptic cells that receive innervation from multiple motoneurons, DGluRIII is abundant at all synapses. However, DGluRIIA and DGluRIIB are differentially localized at the postsynaptic density opposite distinct motoneurons. Hence, innervating motoneurons may regulate the subunit composition of their receptor fields within a shared postsynaptic cell. The capacity of presynaptic inputs to shape the subunit composition of postsynaptic receptors could be an important mechanism for synapse-specific regulation of synaptic function and plasticity.
In VitroIschemic Tolerance Involves Upregulation of Glutamate Transport Partly Mediated by the TACE/ADAM17-Tumor Necrosis Factor-α Pathway
Authors: Romera Cristina , Hurtado Olivia , Botella Sofia H. , Lizasoain Ignacio , Cárdenas Antonio , Fernández-Tomé Paz , Leza Juan C. , Lorenzo Pedro , Moro Maria A.
Published: February 2004

A short ischemic event [ischemic preconditioning (IPC)] can result in a subsequent resistance to severe ischemic injury (ischemic tolerance). Although tumor necrosis factor-α (TNF-α) contributes to the brain damage found after cerebral ischemia, its expression and neuroprotective role in models of IPC have also been described. Regarding the role of TNF-α convertase (TACE/ADAM17), we have recently shown its upregulation in rat brain after IPC induced by transient middle cerebral artery occlusion and that subsequent TNF-α release accounts for at least part of the neuroprotection found in this model. We have now used anin vitromodel of IPC using rat cortical cultures exposed to sublethal oxygen-glucose deprivation (OGD) to investigate TACE expression and activity after IPC and the subsequent mechanisms of ischemic tolerance. OGD-induced cell death was significantly reduced in cells exposed to IPC by sublethal OGD 24 hr before, an effect that was inhibited by the TACE inhibitor BB3103 (1 μm) and anti-TNF-α antibody (2 μg/ml) and that was mimicked by TNF-α (10 pg/ml) preincubation. Western blot analysis showed that TACE expression is increased after IPC. IPC caused TNF-α release, an effect that was blocked by the selective TACE inhibitor BB-3103. In addition, IPC diminished the increase in extracellular glutamate caused by OGD and increased cellular glutamate uptake and expression of EAAT2 and EAAT3 glutamate transporters; however, only EAAT3 upregulation was mediated by increased TNF-α. These data demonstrate that neuroprotection induced by IPC involves upregulation of glutamate uptake partly mediated by TACE overexpression.
Postsynaptic Calcium Influx at Single Synaptic Contacts between Pyramidal Neurons and Bitufted Interneurons in Layer 2/3 of Rat Neocortex Is Enhanced by Backpropagating Action Potentials
Authors: Kaiser Katharina M. M. , Lübke Joachim , Zilberter Yuri , Sakmann Bert
Published: February 2004

Pyramidal neurons in layer 2/3 (L2/3) of the rat somatosensory cortex excite somatostatin-positive inhibitory bitufted interneurons located in the same cortical layer via glutamatergic synapses. A rise in volume-averaged dendritic [Ca2+]ievoked by backpropagating action potentials (APs) reduces glutamatergic excitation via a retrograde signal, presumably dendritic GABA. To measure the rise in local [Ca2+]iat synaptic contacts during suprathreshold excitation, we identified single synaptic contacts in the acute slice preparation in pairs of pyramidal and bitufted cells each loaded with a Ca2+indicator dye. Repetitive APs (10-15 APs at 50 Hz) evoked in a L2/3 pyramidal neuron gave rise to facilitating unitary EPSPs in the bitufted cell. Subthreshold EPSPs evoked a transient rise in [Ca2+]iof 80-250 nmpeak amplitude at the postsynaptic dendritic site. The local postsynaptic [Ca2+]itransient was restricted to ∼10 μm of dendritic length, lasted for ∼200 msec, and was mediated predominantly by NMDA receptor channels. When EPSPs were suprathreshold, the evoked AP backpropagated into the apical and basal dendritic arbor and increased the local [Ca2+]itransient at active contacts by approximately twofold, with a peak amplitude reaching 130-450 nm. This value is in the range of the half-maximal dendritic [Ca2+]i, evoking retrograde inhibition of glutamate release from boutons of pyramids. The localized enhancement of dendritic Ca2+influx at synaptic contacts by synaptically evoked backpropagating APs could represent one mechanism by which a retrograde signal can limit the excitation of bitufted interneurons by L2/3 pyramids when these are repetitively active.
Selective Activation of Corticotropin-Releasing Factor-2 Receptors on Neurochemically Identified Neurons in the Rat Dorsal Raphe Nucleus Reveals Dual Actions
Authors: Pernar Luise , Curtis Andre L. , Vale Wylie W. , Rivier Jean E. , Valentino Rita J.
Published: February 2004

The dorsal raphe (DR)-serotonin (5-HT) system has been implicated in stress-related psychiatric disorders. Stress may impact on this system through corticotropin-releasing factor (CRF), which densely innervates the DR. CRF binds to CRF-R1 and CRF-R2 receptors in the DR and has complex and opposing effects depending on the dose used and the endpoint examined. To clarify the impact of CRF on the DR-5-HT system, the effects of selectively activating CRF-R2 receptors (the predominant subtype) on extracellular DR neuronal activity were examined in halothane-anesthetized rats. Because the DR is neurochemically heterogeneous, when possible, neurons were labeled with neurobiotin for subsequent neurochemical classification as 5-HT or non-5-HT. Relatively low doses of urocortin II (UII) (0.1-10 ng) injected into the DR inhibited most (79%;n= 34) neurons, whereas a higher dose (30 ng) inhibited 28% and activated 41% (n= 29). An analysis of effects on neurochemically identified neurons revealed that 5-HT neurons were inhibited by 0.1-10 ng of UII and activated by 30 ng of UII. Activation of 5-HT neurons by 30 ng of UII likely resulted from disinhibition because the majority of non-5-HT neurons were inhibited by this dose. Antisauvagine-30, but not antalarmin, antagonized UII, implicating CRF-R2 receptors in the effects. The results suggest that activation of CRF-R2 on DR-5-HT neurons inhibits neuronal activity, whereas activation of CRF-R2 receptors on non-5-HT neurons may indirectly excite DR-5-HT neurons through disinhibition. Importantly, the tone of the DR-5-HT system can be regulated in a dynamic manner through CRF-R2 activation, being either decreased or increased depending on the level of endogenous or exogenous ligand.
A Novel Antipyretic Action of 15-Deoxy-Δ12,14-Prostaglandin J2in the Rat Brain
Authors: Mouihate Abdeslam , Boissé Lysa , Pittman Quentin J.
Published: February 2004

Fever is an important part of the host defense response, yet fever can be detrimental if it is uncontrolled. We provide the first evidence that 15-deoxy-Δ12,14-prostaglandin J2(15d-PGJ2), an endogenous ligand for peroxisome proliferator-activated receptor γ (PPARγ), can attenuate the febrile response to lipopolysaccharide (LPS) in rats via an action on the brain. Furthermore, we show that PPARγ is expressed in the hypothalamus, an important locus in the brain for fever generation. In addition, 15d-PGJ2and its synthesizing enzyme (PGD2synthase) were present in rat cerebrospinal fluid, and their levels were enhanced in response to systemic injection of LPS. The antipyretic effect of 15d-PGJ2was associated with reduction in LPS-stimulated cyclooxygenase-2 expression in the hypothalamus but not in p44/p42 mitogen-activated protein kinase phosphorylation or in the expression of the PPARγ.

Thus it is likely that there is a parallel induction of an endogenous prostanoid pathway in the brain capable of limiting deleterious actions of the proinflammatory prostaglandin E2-dependent pathway.