bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating low-temperature fuel cell performance for power generation: fluid dynamics study of phosphoric acid fuel cell systems at the cell level
Authors: Zervas P. L. , Koukou M. K. , Orfanoudakis N. G. , Markatos N-C. G.
Published: September 2006

The development of a detailed mathematical modelling approach for phosphoric acid fuel cells (PAFCs) is described and typical results are presented, discussed, and compared with experimental data found in the literature. A three-dimensional, integrated electrochemical computational-fluid dynamic analysis of a steady-state operation was attempted. The developed model was applied for validation purposes to a specific electrochemical system found in the literature; however, it can be applied to a variety of fuel cell systems. The model has been applied to investigate the effects of various parameters on system performance, justifying the claim that such studies can be very useful tools for optimizing the operation of a PAFC unit or stack. The predictions obtained of the average cell and stack voltage as well as of the generated power show good agreement with the limited experimental data found in the literature.
Hydraulic performance analysis of an axial-flow main coolant pump for the system-integrated nuclear reactor
Authors: Oh H. W. , Yoon E. S. , Park S. J.
Published: September 2006

The hydraulic performance analysis of an axial-flow pump for circulating the coolant in the nuclear reactor has been carried out using the well-established commercial computational fluid dynamics (CFD) code. The predictive capability of the CFD code adopted in the present study was validated in comparison with the experimental data. Predicted performance curves agree fairly well with the experimental results for an axial-flow main coolant pump over the entire operating conditions. The prediction method presented herein can be used efficiently as a tool for the hydraulic design optimization and assist the understanding of the operational characteristics of general purpose axial-flow pumps.
Oil film measurment in polytetrafluoroethylene-faced thurst pad bearings for hydrogenerator applications
Authors: Dwyer-Joyce R. S. , Harper P , Pritchard J , Drinkwater B. W.
Published: September 2006

There is a growing trend in the replacement of the babbit facing in thrust pad bearings with a composite polytetrafluoroethylene (PTFE) surface layer. The PTFE-faced bearings have been shown to allow a greater specific pressure, reduce thermal crowning, and, in some cases, negate the need for an oil-lift (jacking) system. These designs of bearing require new methods for the measurement of oil film thickness both to assist in their development and for plant condition monitoring. In this work, an ultrasonic method of oil film measurement is evaluated for this purpose.

An ultrasonic transducer is mounted on the back face of the thrust pad. Pulses are generated and transmitted through the pad material, bonding interlayer, and PTFE surface layer. The proportion of the wave that reflects back from the oil film layer is determined. This is then related to the oil film thickness using a series of calibration experiments and a spring stiffness model. In practice, the reflected signal is difficult to distinguish, in the time domain, from other internal reflections from the pad. Signals are compared with reflections when no oil film is present and processing is carried out in the frequency domain.

Experiments have been performed on a full size PTFE-faced thrust pad destined for a hydroelectric power station turbine. The instrumented pad was installed in a test facility and subjected to a range of loading conditions both with and without oil lift. Although there were some problems with the robustness of the experimental procedure, oil films were successfully measured and used to study the effect of the oil-lift system on film formation.
A New Chemical Oscillator with a Macrocyclic Copper(II) Complex as Catalyst and Lactic Acid as the Substrate
Authors: Hu Gang , Zhang Zude
Published: September 2006

The oscillatory features of a new type Belousov–Zhabotinskii oscillator with a macrocyclic copper(II) complex [CuL](ClO4)2 as catalyst and lactic acid as the substrate have been reported. This complex contains the ligand 5,7,12,14-tetraethyl-7,14-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. A tentative mechanism based on FKN has been suggested.
Hydrothermal Synthesis and Characterization of Magnesium Borate Hydroxide Nanowhiskers
Authors: Zhu Wancheng , Xiang Lan , He Taobo , Zhu Shenlin
Published: September 2006

Magnesium borate hydroxide (MgBO2(OH)) nanowhiskers with a diameter of 20–50 nm and a length of 0.5–3 μm were synthesized via a facile hydrothermal route, using MgCl2·6H2O, H3BO3, and NaOH as the reactants. Mg7B4O13·7H2O with poor crystallinity was formed after coprecipitation of the reactant solutions at room temperature, the hydrothermal treatment of the slurry at 240 °C for 18 h led to the formation of uniform MgBO2(OH) nanowhiskers with high crystallinity and preferential growth direction along the (200) plane.
Grafting Organic and Biomolecules on H-Terminated Porous Silicon from a Diazirine
Authors: Wei Shuai , Wang Jing , Guo Dong-Jie , Chen Ya-Qing , Xiao Shou-Jun
Published: September 2006

A diazirine compound, 1,4-(1-azi-2,2,2-trifluoroethyl)benzoic acid, was used as a stable carbene precursor to react with Si–H terminated porous silicon (PSi) under microwave irradiation. After formation of a molecular monolayer, the end carboxyl group was converted to an amine-reactive crosslinker species, NHS ester, and finally to a Bovine Serum Albumin (BSA) monolayer on PSi.
UV–Ozone Treatments Improved Carbon Black Surface for Direct Electron-transfer Reactions with Bilirubin Oxidase under Aerobic Conditions
Authors: Tominaga Masato , Otani Mai , Kishikawa Mari , Taniguchi Isao
Published: September 2006

Direct electron-transfer reactions of bilirubin oxidase (BOD) adsorbed onto carbon black (CB) were observed. Heterogeneous electron-transfer rate constants (k°) between BOD and CB were evaluated by analyzing steady-state catalytic voltammograms using a rotating electrode system. By the use of CB treated with UV–ozone, improvements in k° values were observed.
Novel Hydrophobic Brønsted Acidic Ionic-liquids as Efficient and Reusable Catalysts for Organic Reactions in Water
Authors: Gu Yanlong , Ogawa Chikako , Kobayashi Shu
Published: September 2006

Novel hydrophobic Brønsted acidic ionic liquids (HBAIL) were prepared and utilized as acid catalysts in organic reactions in water. HBAILs were demonstrated, for the first time, to be effective catalysts for Prins cyclization of styrene derivatives in water with a formaldehyde water solution. Many styrene derivatives could be successfully converted to the corresponding 1,3-dioxanes. Other dehydration reactions also proceeded well using HBAILs in water. After reactions, HBAILs could be easily recovered and reused without significant loss of activity.
State Medicaid and private payer reimbursement for telemedicine: An overview
Authors: Brown Nancy A
Published: September 2006

Individual states in the USA were given the option of paying for telemedicine services with Medicaid (i.e. federal health-care funds administered by the state) in 1998, when the Health Care Financing Administration (HCFA) published final rules for Medicare payment for teleconsultations in health professional shortage areas (HPSAs). It was left to telemedicine practitioners in each state to negotiate the scope of the services covered with the state Medicaid office. Three reports of data gathered by 2002–03 surveys on state reimbursement policies have been reviewed, with additional information from a brief informal 2005 survey conducted by the author. In the seven years since 1998, 34 states have added coverage of telemedicine services to their Medicaid programmes, although there are wide variations in service coverage, payment policies, and geographical and other restrictions. There is less published information on private payer reimbursement. One survey performed by AMD Telemedicine (AMD) and the American Telemedicine Association (ATA) showed that over half of the 72 telemedicine programmes in 25 states delivering billable services were being reimbursed by private payers. In 1999, 43% of responding telemedicine networks saw reimbursement as a barrier to long-term sustainability, while in 2004 only 22% did so. It appears that some progress has been made in Medicaid and private payer reimbursement for telemedicine.
Diagnosis, access and outcomes: Update of a systematic review of telemedicine services
Authors: Hersh William R , Hickam David H , Severance Susan M , Dana Tracy L , Krages Kathryn Pyle , Helfand Mark
Published: September 2006

Telemedicine services are being increasingly used. Although insurers and other payers are covering some services in the USA, the rationale for these coverage decisions is not always evidence-based. We reviewed the literature for telemedicine services that substitute for face-to-face medical diagnosis and treatment. We focused on three types of telemedicine services: store-and-forward, home-based and office/hospital-based services. Studies were included if they were relevant to at least one of the three study areas, addressed at least one key question and contained reported results. We excluded articles that did not study a service requiring face-to-face encounters (i.e. teleradiology was excluded). Our search initially identified 4083 citations. After review, 597 were judged to be potentially relevant at the title/abstract level. Following a full-text review, 106 studies were included. Store-and-forward services have been studied in many specialties, the most common being dermatology, wound care and ophthalmology. The evidence for their efficacy is mixed. Several limited studies showed the benefits of home-based telemedicine interventions in chronic diseases. Studies of office/hospital-based telemedicine suggest that telemedicine is most effective for verbal interactions, e.g. videoconferencing for diagnosis and treatment in specialties like neurology and psychiatry. There are still significant gaps in the evidence base between where telemedicine is used and where its use is supported by high-quality evidence. Further well-designed research is necessary to understand how best to deploy telemedicine services in health care.
Health delivery system changes required when integrating telemedicine into existing treatment flows of information and patients
Authors: Shea Steven
Published: September 2006

Business model and financial recovery issues dominate discussions about using telemedicine to improve chronic disease management. The technical issues are numerous, daunting and complex, but many can be addressed using the resources and infrastructure available in large, well-integrated clinical information systems. The cost-benefit balance will change when it becomes possible to use devices that are owned by patients for everyday use, rather than installing special-purpose devices for telemedicine. Technology and communications capabilities are driven mainly by market factors other than uses for health care. Provider-side telemedicine capabilities, specifically for upload, storage and display of home medical data, will improve as technology develops. How health-care providers will process the larger amount of data made available by telemedicine is a clinical issue, but it is likely that software will emerge to assist in this task. The alignment of financial incentives for health-care providers is a decisive factor in understanding why telemedicine has had substantial deployment within the US Veterans Hospital Administration system, and to some extent within prison health systems and the Kaiser Permanente Health Plan, but much less widely in other settings.
What lessons can be learned from telemedicine programmes in other countries?
Authors: Ohinmaa Arto
Published: September 2006

Reviews of telemedicine literature have shown that about half of the published studies come from the USA. This suggests that there is a large potentially useful stock of research outside the USA that could be used to guide telemedicine decision-making in the USA. In the present study, a request was sent to eight international experts in telemedicine asking about successful telemedicine programmes that have been assessed and could potentially be implemented in the US health-care system. We also conducted a focused review of a few key publications in the field to identify examples of successful telemedicine programmes. The review found that in some specific areas, such as teleradiology, telemental health, telegeriatric applications, e-referrals and discharge letters, and integration of health-care organizations with telemedicine networks, applications successfully implemented in international settings would be suitable for implementation in the USA. If telemedicine programmes from other countries are disseminated to the USA, differences in health-care systems, and technological infrastructure will probably affect their chances of success.
Telehealth and the national health information technology strategic framework
Authors: Speedie Stuart M , Davies Diane
Published: September 2006

Telehealth has a role in the federally sponsored plan for health information technology (HIT) that encompasses electronic health records (EHRs) and the National Health Information Network (NHIN). The goals of telehealth and the national plan are complementary. One focuses on improving access to high quality health-care services and the other on the information systems to support those services. Telehealth needs the fully realized EHR to provide the best possible care when patients are geographically and chronologically separated from their providers. Some current telehealth projects are natural examples of how a distributed, accessible EHR such as that envisaged by the plan can be used to provide better care. The experiences of telehealth in organizing large networks of heterogeneous health-care entities can provide useful lessons as the process of implementing HIT moves forward.
Standards for data collection and monitoring in a telemedicine research network
Authors: Yellowlees Peter , Harry David
Published: September 2006

While a networked, nationwide health information system is financially and logistically impractical, the development of independent, regional systems is realistic and feasible. A Telemedicine Research Network (TRN) could connect a number of geographically disparate health systems. This would require the reconciliation of policies and practices in five principal areas: partner agreement on project scope; privacy, security and confidentiality; technical standards; telecommunications and computer infrastructure; change management and training. Initial establishment of a first-stage TRN would require very little technical development and would, instead, rely on trust among the partners. The development of standards-based TRNs will greatly increase the quality and quantity of telemedicine research.
Role of Gymnastics in the Army School of Physical Training
Authors: Griffiths DE , Hargrove R , Clasper J
Published: September 2006

INTRODUCTION

As a result of a single spinal injury seen at Frimley Park Hospital, we reviewed the injuries recorded at the Army School of Physical Training since December 1996.

PATIENTS AND METHODS

This was a retrospective review of all acute accidents and injuries recorded in the Accident Book since its inception.

RESULTS

Over 75% of the injuries that were serious enough to result in soldiers having their training terminated were as a direct result of gymnastic events such as vaulting, trampolining and somersaults. These events were also responsible for most of the small number of career-threatening injuries.

CONCLUSIONS

This raises questions about the inclusion of gymnastic events in course training programmes, especially when considering its relevance to army training in general.
Contamination and Decontamination of Doppler Probes
Authors: Whitehead Emma J , Thompson John F , Lewis David R
Published: September 2006

INTRODUCTION

Nosocomial infection occurs in 2–9% of patients undergoing vascular surgery and can lead to death, amputation or require complex revision surgery. Neck ties, pagers, stethoscopes and Doppler probes have been shown to carry pathogens. We measured bacterial colonisation of Doppler probes on a vascular unit and audited the effect of staff education at reducing this contamination.

MATERIALS AND METHODS

Bacteriological culture swabs were taken from hand-held Doppler probes on the vascular surgical ward and clinic. There was no protocol for cleaning the Doppler probes, so manufacturers were contacted for their recommendations. The results of cultures were presented to nursing and medical staff, who were then asked to clean the probes with alcohol wipes after each use. After an interval of 1 week, bacteriological cultures from the same Doppler probes was repeated.

RESULTS

Fifty bacteriological cultures were performed from 10 Doppler probes over a 4-week period. Thirteen (26%) cultures were positive for diphtheroids, coliforms, coagulase-negative staphylococci and skin flora. After staff education, 42 further swabs were taken from the same probes; two positive cultures were obtained with scanty growth of skin flora (χ2 P < 0.05).

CONCLUSIONS

Staff education and simple cleaning significantly reduces the contamination of hand-held Doppler probes and may help prevent nosocomial infection.
Vestibular Schwannoma Management: Current Practice Amongst UK Otolaryngologists – Time for a National Prospective Audit
Authors: Saeed Shakeel R , Suryanarayanan Ranga , Dezso Attila , Ramsden Richard T
Published: September 2006

INTRODUCTION

It is generally agreed that the successful management of a vestibular schwannoma (VS) usually involves close collaboration between a neuro-otologist and neurosurgeon. In addition, it is accepted that the experience of the team managing such tumours is one of the key determinants of outcome after surgical intervention. The aim of this study was to identify current practice in the management of such tumours amongst otolaryngologists in the UK and to observe whether such collaborative working practices exist.

MATERIALS AND METHODS

A cross sectional postal questionnaire survey of consultant members of the British Association of Otorhinolaryngologists – Head and Neck Surgeons (n = 542).

RESULTS

A total of 336 replies were received (62%). Of respondents, 299 consultants referred their patients to another surgeon for further management; 242 referred to another ENT surgeon (80.9%), 29 to a neurosurgeon (9.7%) and 28 to a combined team (9.4%). Twenty-eight of the responding otolaryngologists (8.6%) managed the tumours themselves, of whom 22 worked with a neurosurgeon. Of these 28 neuro-otologists, nearly two-thirds (64%) had been undertaking VS surgery for more than 10 years. The total number of patients with a VS referred to these 28 consultants during 2001 was 775, with a mean caseload of 29.8, median 23 and a range of 4 to 102 per surgeon. Seven of the 28 otolaryngologists chose their surgical approach entirely based on the size of the tumour. Eight consultants preferred the sub-occipital (SO) approach, 10 the trans-labyrinthine (TL) approach, three chose between SO and TL approaches. The majority of surgeons had a prospective, computer-based data collection and were willing to give further information about their outcomes and complications.

CONCLUSIONS

Amongst the otolaryngologists surveyed in the UK, we have identified 28 neuro-otologists who undertake VS surgery. The majority work with neurosurgical colleagues, confirming collaborative practice. The wide range in caseload raises the issue of training and maintaining standards and in the first instance we recommend a prospective national audit of VS management and outcomes with our neurosurgical colleagues. This would also be of value in manpower planning particularly if a minimum caseload could be identified below which results were seen to be less good.
Re-Admission Rates within 28 Days of Total Hip Replacement
Authors: Cullen C , Johnson DS , Cook G
Published: September 2006

INTRODUCTION

The aim of the study was to identify the reasons for the higher than expected emergency re-admission to hospital within 28 days of total hip replacement (THR) for Stepping Hill Hospital, Stockport.

PATIENTS AND METHODS

Over a 42-month period, 65 (8.5%) of 769 patients were re-admitted within 28 days of discharge following primary THR. Case notes for 61 patients were available for retrospective review to assess premorbidity, initial postoperative complications and reason for re-admission.

RESULTS

The main reasons for re-admission were complications related to the procedure. These included thrombo-embolic disease 2.5%, atraumatic dislocation 1.4%, wound complications 1.2% and swollen limb 1.8%. Other causes such as admission to another department for problems not related to THR accounted for 0.8%.

CONCLUSIONS

Our findings are comparable with the published literature for early complications following THR. The three main reasons for re-admission were atraumatic dislocation, thrombo-embolic and wound complications such as superficial infection and haematoma are the commonest world-wide. The re-admission rate to hospital within the first 28 days following THR was a clinical indicator suggested by the UK Department of Health. It has subsequently been incorporated in a group of indicators used by the CASPE Healthcare Knowledge Systems (CHKS), a private healthcare consultancy and analysis company, for peer benchmarking. Our re-admission rates are inflated by admissions for non-THR-related reasons. The level of post-THR complications leading to re-admission were acceptable compared with the available published literature regarding 28-day re-admission. We anticipate that this study may act as a benchmark for other trusts.
Teaching and Assessing Surgical Competence
Authors: Thomas WEG
Published: September 2006

Surgical competence and its assessment is one of the most hotly debated topics engaging the profession. In the current climate of diminishing working hours and shorter training, the surgical profession is having to address the complex issue as to how surgery as a craft specialty should be taught, and how to assess when an individual is competent within their chosen sphere as well as how that competence should be maintained. Internationally, there is political pressure upon the professional to achieve contracted activity to comply with political imperatives and, at the same time, to achieve a greater degree of specialisation. Within Europe, the working time directive has led to a shift system of rotas and this, along with a shorter overall period of training, has led to reduced time available to surgical trainees in which to learn their craft.
Survey of the Management of Acute Traumatic First-Time Anterior Shoulder Dislocation Among Trauma Clinicians in the UK
Authors: Chong Mark , Karataglis Dimitris , Learmonth Duncan
Published: September 2006

INTRODUCTION

The aim of this work was to survey how acute traumatic first-time anterior shoulder dislocation (AFSD) is managed among trauma clinicians in UK using a postal questionnaire.

PATIENTS AND METHODS

A total of 150 questionnaires were sent out to active consultant members of the British Trauma Society in the UK. Questions were laid out in two ‘workgroups’. In Workgroup One, an assortment of questions was included regarding choices and methods of analgesia, methods of monitoring used, methods of reduction, and position of immobilisation. In Workgroup Two, three different case scenarios were analysed to look into the ‘post-reduction’ management.

RESULTS

The response rate was 60%. Of respondents, 22% have a local protocol for managing AFSD. Almost all respondents recommended pre- and post-reduction X-rays as standard practice. Most respondents favoured systemic analgesia and sedation with airways' monitoring, as opposed to intra-articular anaesthesia (68 versus 9). Eighty-four respondents advocated immobilisation in internal rotation compared to six in external rotation. Only 19% (16 of 84) of respondents would perform an immediate arthroscopic stabilisation in young, fit patients presenting with this type of injury.

CONCLUSIONS

This survey revealed variations among trauma clinicians in managing AFSD on the ‘front-line’. There is a need to address the issue of intra-articular analgesia, immobilisation technique and management of AFSD in the young patient with regards to immediate surgical intervention. We suggest that these issues be revised and clarified, ideally in a randomised, controlled, clinical trial prior to the introduction of a protocol for managing this problem.
Light-Emitting-Diode-Based Light Source for Calibration of an Intensified Charge-Coupled Device Detection System Intended for Galvanoluminescence Measurements
Authors: Kasalica B. V. , Belca I. D. , Stojadinovic S. Dj. , Zekovic Lj. D. , Nikolic D.
Published: September 2006

A spectrally tunable light source utilizing three light-emitting diodes (LEDs) for calibration of a highly sensitive intensified charge-coupled device (ICCD) optical detection system intended for time-resolved galvanoluminescence (GL) measurements is described. The source has been conceived as a low-cost substitute for standard tungsten lamps usually used for relative and absolute calibration of optical detection systems. Three LEDs with different spectral characteristics in conjunction with a system of two integrating spheres as light mixers and light reducers are used. This construction provides control over the source spectrum by changing individual LED contributions. The use of integration spheres eliminated angular distribution of light intensities of LEDs as well as angular dependence of their spectral contributions. Moreover, by using the source we have avoided the problem of stray and diffuse light of higher wavelengths, as well as different light intensities for different wavelengths (up to three orders of magnitude in the range from 400 nm to 750 nm), which we have with standard tungsten lamps. A complete calibration procedure for the LED source and ICCD detection system is described. Finally, for the first time, we have performed time-resolved spectral GL measurements during aluminum anodization in porous film-forming electrolyte phosphoric acid in a transient regime. Two peaks at 425 nm and 595 nm are recognized, confirming the same mechanism of GL in both transient and steady-state regimes of anodization.
Removal of Analyte-Irrelevant Variations in Near-Infrared Tissue Spectra
Authors: Yang Ye , Shoer Leah , Soyemi Olusola O. , Landry Michelle R. , Soller Babs R.
Published: September 2006

This paper describes mathematical techniques to correct for analyte-irrelevant optical variability in tissue spectra by combining multiple preprocessing techniques to address variability in spectral properties of tissue overlying and within the muscle. A mathematical preprocessing method called principal component analysis (PCA) loading correction is discussed for removal of inter-subject, analyte-irrelevant variations in muscle scattering from continuous-wave diffuse reflectance near-infrared (NIR) spectra. The correction is completed by orthogonalizing spectra to a set of loading vectors of the principal components obtained from principal component analysis of spectra with the same analyte value, across different subjects in the calibration set. Once the loading vectors are obtained, no knowledge of analyte values is required for future spectral correction. The method was tested on tissue-like, three-layer phantoms using partial least squares (PLS) regression to predict the absorber concentration in the phantom muscle layer from the NIR spectra. Two other mathematical methods, short-distance correction to remove spectral interference from skin and fat layers and standard normal variate scaling, were also applied and/or combined with the proposed method prior to the PLS analysis. Each of the preprocessing methods improved model prediction and/or reduced model complexity. The combination of the three preprocessing methods provided the most accurate prediction results. We also performed a preliminary validation on in vivo human tissue spectra.
Analysis of the Effect of Particle Size on Polymorphic Quantitation by Raman Spectroscopy
Authors: Hu Yuerong , Wikström Hakån , Byrn Stephen R. , Taylor Lynne S.
Published: September 2006

Raman spectroscopy has been widely used to monitor various aspects of the crystallization process. Although it has long been known that particle size can influence Raman signal, relatively little research has been conducted in this area, in particular for mixtures of organic materials. The aim of this study was to investigate the effect of particle size on quantification of polymorphic mixtures. Several sets of calibration samples containing different particle size fractions were prepared and Raman spectra were collected with different probes. Calibration models were built using both univariate and multivariate analysis. It was found that, for a single component system, Raman intensity decreased with increasing particle size. For mixtures, calibration models generated from the same particle size distribution as the sample yielded relatively good predictions of the actual sample composition. However, if the particle sizes of the calibration and unknown samples were different, prediction errors resulted. For extreme differences in particle sizes, prediction errors of up to 20% were observed. Prediction errors could be minimized by changing the sampling optics employed.
In situ Raman Spectroscopic Study of the Dissociation of Methane Hydrate at High Pressure
Authors: Sun Q. , Zheng H. F.
Published: September 2006

The dissociation of methane hydrate at high pressure is studied by in situ Raman spectroscopy in a diamond-anvil cell. As for the Raman spectrum of sI methane hydrate, the v1 band of CH4 is split into two peaks v′1 and v′1, indicating the partitioning of CH4 between the large (51262) and small (512) cavities, respectively. With increasing temperature, the intensity ratio of Iv′1/ Iv′1 decreases obviously, and the d( Iv′1/ Iv′1)/d T is −0.079 K−1. Additionally, the v1 band of the dissolved CH4 is close to v′1 of the CH4 molecule engaged in the small 512 cavity. This implies that, in the initial stage of hydrate formation, the abundance of small 512 cavities is greater than that of large 51262 cavities.
Studying Bacterial Metabolic States Using Raman Spectroscopy
Authors: Escoriza Maria Fernanda , Vanbriesen Jeanne M. , Stewart Shona , Maier John
Published: September 2006

Natural metabolic variability expected during characteristic growth phases in batch cultures of Escherichia coli and Staphylococcus epidermidis were studied by Raman spectroscopy. Spectral changes induced by metabolic changes found in the growth phases (i.e., lag, exponential, stationary, and decay) were identified. Maximum intensity of bands assigned to DNA and RNA bases are seen at the beginning of the exponential phase, when cells are metabolically active, and minimum intensities are seen when cells are decaying. High agreement in spectral variation due to growth phases was seen for all the trials that were performed, four growth cycles for E. coli and two for S. epidermidis. Batch cultures were monitored by standard plate counts to identify all growth phases, including decay. Spectral data were analyzed by principal component analysis (PCA) and discriminant analysis to identify similarities and differences and to estimate a classification performance based on growth phases. For the species evaluated, spectra during decay are grouped closer to each other and separated from lag, exponential, and stationary cells. These results suggest that Raman spectroscopy can be used to study metabolic states in bacteria and in particular cell viability.
Fluorescence-Suppressed Raman Technique for Quantitative Analysis of Protein Solution Using a Micro-Raman Probe, the Shifted Excitation Method, and Partial Least Squares Regression Analysis
Authors: Oshima Yusuke , Komachi Yuichi , Furihata Chie , Tashiro Hideo , Sato Hidetoshi
Published: September 2006

A practical Raman analyzing technique with suppression of the strong fluorescent background in order to obtain quantitative information is proposed in the present study. The technique is based on the shifted excitation method and partial least squares regression (PLSR) analysis. The Raman system consists of a single Raman spectrometer, a background-free electrically tunable Ti: Sapphire laser (BF-ETL), and a micro-Raman probe (MRP). The system allows one to obtain reliable shifted excitation Raman spectra with a simple operation. The PLSR analysis successfully provides quantitative information from the obtained spectra with the suppression of random noise including photon shot noise. The present study demonstrates that the technique is effective for extracting quantitative information concealed behind a fluorescent background that is more than 200 times stronger than the Raman signal.
Fluorescence of Aromatic Amines and Their Fluorescamine Derivatives for Detection of Explosive Vapors
Authors: Eastwood Delyle , Fernandez Carlos , Yoon B. Yunghoon , Sheaff Chrystal N. , Wai Chien M.
Published: September 2006

Nitroaromatics (such as dinitrotoluene, trinitrotoluene, and nitrobenzene) found in explosive vapors from buried landmines can be reduced to aminoaromatics by a novel process involving Pd metal nanocatalysts prepared in supercritical fluid carbon dioxide and supported on multi-walled carbon nanotubes. These aminoaromatics are fluorescent and, if desired, the fluorescence yield can be increased and the fluorescence maxima shifted further toward the red by reaction with appropriate derivatizing agents such as fluorescamine. Corrected spectra for these chemicals and their derivatives are included. Subpicomolar detection limits have already been achieved using a laboratory spectrofluorometer with a 150 W Xe arc lamp. Using lasers as excitation sources, this approach has the potential for developing a field sensor competitive with other methods currently used for detecting explosive vapors from land mines.
Correcting Attenuated Total Reflection—Fourier Transform Infrared Spectra for Water Vapor and Carbon Dioxide
Authors: Bruun Susanne W. , Kohler Achim , Adt Isabelle , Sockalingum Ganesh D. , Manfait Michel , Martens Harald
Published: September 2006

Fourier transform infrared (FT-IR) spectroscopy is a valuable technique for characterization of biological samples, providing a detailed fingerprint of the major chemical constituents. However, water vapor and CO2 in the beam path often cause interferences in the spectra, which can hamper the data analysis and interpretation of results. In this paper we present a new method for removal of the spectral contributions due to atmospheric water and CO2 from attenuated total reflection (ATR)-FT-IR spectra. In the IR spectrum, four separate wavenumber regions were defined, each containing an absorption band from either water vapor or CO2. From two calibration data sets, gas model spectra were estimated in each of the four spectral regions, and these model spectra were applied for correction of gas absorptions in two independent test sets (spectra of aqueous solutions and a yeast biofilm ( C. albicans) growing on an ATR crystal, respectively). The amounts of the atmospheric gases as expressed by the model spectra were estimated by regression, using second-derivative transformed spectra, and the estimated gas spectra could subsequently be subtracted from the sample spectra. For spectra of the growing yeast biofilm, the gas correction revealed otherwise hidden variations of relevance for modeling the growth dynamics. As the presented method improved the interpretation of the principle component analysis (PCA) models, it has proven to be a valuable tool for filtering atmospheric variation in ATR-FT-IR spectra.
Nitrate Determination Using Anion Exchange Membrane and Mid-Infrared Spectroscopy
Authors: Linker Raphael , Shaviv Avi
Published: September 2006

This study investigates the combined use of an anion exchange membrane and transmittance mid-infrared spectroscopy for determining nitrate concentration in aqueous solutions and soil pastes. The method is based on immersing a small piece (2 cm2) of anion exchange membrane into 5 mL of solution or soil paste for 30 minutes, after which the membrane is removed, rinsed, and wiped dry. The absorbance spectrum of the charged membrane is then used to determine the amount of nitrate sorbed on the membrane. At the levels tested, the presence of carbonate or phosphate does not affect the nitrate sorption or the spectrum of the charged membrane in the vicinity of the nitrate band. Sulfate affects the spectrum of the charged membrane but does not prevent nitrate determination. For soil pastes, nitrate sorption is remarkably independent of the soil composition and is not affected by the level of soil constituents such as organic matter, clay, and calcium carbonate. Partial least squares analysis of the membrane spectra shows that there exists a strong correlation between the nitrate charge and the absorbance in the 1000–1070 cm−1 interval, which includes the v1 nitrate band located around 1040 cm−1. The prediction errors range from 0.8 to 2.1 μeq, which, under the specific experimental conditions, corresponds to approximately 2 to 6 ppm N–NO3− on a solution basis or 2 to 5 mg [N]/kg [dry soil] on a dry soil basis.
Circulating Blood Volume Determination Using Electronic Spin Resonance Spectroscopy
Authors: Facorro Graciela , Bianchin Ana , Boccio José , Hager Alfredo
Published: September 2006

There have been numerous methods proposed to measure the circulating blood volume (CBV). Nevertheless, none of them have been massively and routinely accepted in clinical diagnosis. This study describes a simple and rapid method, on a rabbit model, using the dilution of autologous red cells labeled with a nitroxide radical (Iodoacetamide-TEMPO), which can be detected by electronic spin resonance (ESR) spectroscopy. Blood samples were withdrawn and re-injected using the ears' marginal veins. The average CBV measured by the new method/body weight (CBVIAT/BW) was 59 ± 7 mL/kg ( n = 33). Simultaneously, blood volume determinations using the nitroxide radical and 51Cr (CBVCr) were performed. In the plot of the difference between the methods (CBVIAT – CBVCr) against the average (CBVIAT + CBVCr)/2, the mean of the bias was – 1.1 ± 6.9 mL and the limits of agreement (mean difference ± 2 SD) were 14.9 and 12.7 mL. Lin's concordance correlation coefficient pc = 0.988. Thus, both methods are in close agreement. The development of a new method that allows a correct estimation of the CBV without using radioactivity, avoiding blood manipulation, and decreasing the possibility of blood contamination with similar accuracy and precision of that of the “gold standard method” is an innovative proposal.
Cell Discrimination by Attenuated Total Reflection—Fourier Transform Infrared Spectroscopy: The Impact of Preprocessing of Spectra
Authors: Gaigneaux A. , Ruysschaert J. M. , Goormaghtigh E.
Published: September 2006

Fourier transform infrared (FT-IR) spectroscopy has become a powerful tool for biodiagnostics and cell line classification. Typical experimental perturbations included in spectra are baseline shift and scale variation between spectra. They have to be removed by data preprocessings to allow further data analysis and classification. In this work, we addressed baseline shift corrections and normalizations in attenuated total reflection (ATR) FT-IR spectra. We compared the efficiency of several preprocessing methods with series of spectra containing typical perturbations (baseline shift, scaling factor, and noise) and a priori known definite spectral difference. Several baseline-correction and normalization possibilities were evaluated. Our results were generally sensitive, selective, and robust with respect to baseline and scaling. Full-range scaling generated more false-positive results. Use of first- and second-derivative spectra was tested. Results obtained on model spectra were confirmed with series of spectra from sensitive and multidrug-resistant leukemia K562 cells. We showed that the use of derived spectra did not provide more efficiency and required additional preprocessing such as smoothing to obtain results similar to those obtained from non-derived ones. On the other hand, results obtained with derivatives were less sensitive to scaling, a useful feature when scaling is problematic.
Combining the Tape-Lift Method and Fourier Transform Infrared Spectroscopic Imaging for Forensic Applications
Authors: Ricci Camilla , Chan K. L. Andrew , Kazarian Sergei G.
Published: September 2006

Conventional Fourier transform infrared (FT-IR) spectroscopy and microscopy have been widely used in forensic science. New opportunities exist to obtain chemical images and to enhance the spatial resolution using attenuated total reflection (ATR) FT-IR spectroscopy coupled with a focal-plane array (FPA) detector. In this paper, the sensitivity limits of FT-IR imaging using three different ATR crystals (Ge, ZnSe, and diamond) in three different optical arrangements for the detection of model particles is discussed. Model systems of ibuprofen and paracetamol particles having sizes below 32 μm were studied. The collection of drug particles was achieved with the aid of two different tapes: common adhesive tape and a film of polydimethylsiloxane (PDMS). The surface of the film with collected particles was measured directly via ATR-FT-IR imaging. Since the removal of tape from porous surfaces can be difficult, the application of micro ATR-FT-IR imaging directly to the surface of a newspaper contaminated with particles of model drugs is also discussed. In order to assess the feasibility of the chosen method in a forensic case study, the detection of diacetylmorphine hydrochloride traces in PDMS matrix and the finger surface is investigated. The scenarios considered were that of the detection of evidence collected at a crime scene with the tape lift method and the analysis of the finger of an individual after drug handling. The results show broad implications in the detection of drugs of abuse.
O2-Responsive Chemical Sensors Based on Hybrid Xerogels That Contain Fluorinated Precursors
Authors: Bukowski Rachel M. , Davenport Michael D. , Titus Albert H. , Bright Frank V.
Published: September 2006

We report the development and analytical figures of merit associated with several new O2-responsive sensor materials. These new sensing materials are formed by sequestering the luminophore tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) ([Ru(dpp)3]2+) within hybrid xerogels that are composed of two of the following methoxysilanes: tetramethoxysilane, n-propyl-trimethoxysilane, 3,3,3-trifluoropropyl-trimethoxysilane, phenethyl-trimethoxysilane, and pentafluorophenylpropyl-trimethoxysilane. Steady-state and time-resolved luminescence measurements are used to investigate these hybrid xerogel-based sensor materials and elucidate the underlying reasons for the observed performance. The results show that many of the [Ru(dpp)3]2+-doped composites form visually uniform, crack-free xerogel films that can be used to construct O2 sensors that have linear calibration curves and excellent long-term stability. To the best of our knowledge, the [Ru(dpp)3]2+-doped fluorinated hybrid xerogels also exhibit the highest O2 sensitivity of any reported [Ru(dpp)3]2+-based sensor platform.
Social values dynamics and socio-economic development
Authors: Ramos Alice
Published: September 2006

Based on data from nineteen countries participating in the European Social Survey 2002, the Schwartz model of social values is analysed in three perspectives: structure, importance and consensus. Results show the equivalence of Schwartz's values structure in the countries analysed. A multi-level analysis was performed in order to test the impact of both individual (family income) and contextual (Gross Domestic Product purchasing power parity GDP ppp) factors on value priorities. Differences in the importance people attribute to values were identified between countries, but results from the multi-level analysis showed that GDP ppp as well as family income were not good predictors of value priorities. In what concerns value consensus, and contrary to some previous results reported in the literature, a negative correlation between socio-economic development and consensus was found, suggesting that the higher the socio-economic development, the higher the social heterogeneity and complexity of social values.
So far so good? Subjective and social well-being in Portugal and Europe
Authors: Lima Maria Lusa , Novo Rosa Novo
Published: September 2006

Based on the results of the European Social Survey (ESS), this study characterizes the levels of subjective well-being (SWB) and social well-being (SoWB) in 20 European countries. The relationships between well-being, socio-demographic and behavioural variables (sociability and social participation) were also explored. Results show extremely low levels of well-being in Portugal as compared to the other European countries, but similar to other less-developed countries. Wealth of the country was, as usual, associated with SWB and also with SoWB. Overall, for developed countries, our results replicate the associations of SWB with age, marital status and income. However, in less-developed countries these associations with SWB are different: it is positively associated with income and negatively associated with age; it is higher in individuals that were never married and is more strongly related to sociability. These results challenge a universal model of well-being and stress its contextual and social determinants.
Disinfection of Wastewater by Hydrogen Peroxide or Peracetic Acid: Development of Procedures for Measurement of Residual Disinfectant and Application to a Physicochemically Treated Municipal Effluent
Authors: Wagner Monika , Brumelis Daina , Gehr Ronald
Published: September 2006

The Montreal Urban Community Wastewater Treatment Plant (MUCWTP) located in Montreal, Quebec, Canada, uses physicochemical treatment processes prior to discharging wastewater into the St. Lawrence River via an outfall tunnel of 2 hours retention time. Although chlorination facilities exist, they are not being used, and the MUCWTP is seeking alternative methods for disinfection to achieve a 2‐ to 3‐log fecal coliform reduction. Liquid chemical disinfectants were attractive options because of their low capital costs. This led to an investigation of the feasibility of using hydrogen peroxide or peracetic acid. A method for measuring peroxycompounds (hydrogen peroxide or peracetic acid plus hydrogen peroxide) was developed using the peroxidase‐based oxidation of 2,2′‐azino‐bis(3‐ethylbenz‐thiazoline‐6‐sulfuric acid) diammonium salt (ABTS) with hydrogen peroxide. The validity of the method was confirmed using effluent from the MUCWTP. Recovery was higher than 90% for peracetic acid levels as low as 1.0 mg/L. Quenching of hydrogen peroxide was achieved with 50‐mg/L catalase; quenching of peracetic acid was achieved with 100 mg/L of sodium thiosulfate, followed by 50 mg/L of catalase. Batch disinfection tests were conducted on MUCWTP effluent. Hydrogen peroxide and peracetic acid in wastewater over time could be modeled as a second‐order decay, with the decay “constant” being a function of the initial concentration of peroxycompounds. This function was the same for both hydrogen peroxide and peracetic acid, possibly indicating similar decomposition pathways in wastewater matrices. Disinfection was modeled using a modified Hom equation. Required doses of hydrogen peroxide to reach the target fecal coliform levels ranged from 106 to 285 mg/L, with the higher doses occurring when ferric chloride instead of alum was used as the coagulant. Hence, hydrogen peroxide was infeasible as a disinfectant for this application. On the other hand, the peracetic acid dose needed to achieve the target fecal coliform level was only 0.6 to 1.6 mg/L. Therefore, peracetic acid seems to be a promising disinfectant for physicochemical or primary effluent, or combined sewer overflows.