bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo role of the phosphate groove of PDK1 defined by knockin mutation
Authors: Collins Barry J. , Deak Maria , Murray-Tait Vicky , Storey Kate G. , Alessi Dario R.
Published: October 2005

AGC kinases are mediators of signalling responses stimulated by agonists and are activated following phosphorylation at their T-loop residue by the 3-phosphoinositide-dependent protein kinase-1 (PDK1). Agonists stimulate the activation of the AGC kinases p70 ribosomal S6 kinase (S6K), p90 ribosomal S6 kinase (RSK) and serum and glucocorticoid-induced protein kinase (SGK), by inducing the phosphorylation of these enzymes at a non-catalytic regulatory site termed the hydrophobic motif. This creates a high-affinity docking site enabling PDK1 to bind and phosphorylate the T-loop of these enzymes. The site that interacts with these substrates is located on the small lobe of the catalytic domain of PDK1 and is composed of a hydrophobic groove next to a basic phosphate groove. The disruption of the hydrophobic groove ablates activation of S6K, RSK and SGK, but the role of the phosphate groove in regulating the function of PDK1 has not been explored in vivo. We generated knockin ES cells, in which both copies of the gene encoding PDK1 were altered to express a form of PDK1 that retains catalytic activity and integrity of the hydrophobic groove, but in which the phosphate groove was disrupted. The knockin ES cells were viable, mutant PDK1 was expressed at normal levels and IGF1 induced activation of protein kinase B (PKB/Akt), which is a PDK1 substrate that does not require hydrophobic motif phosphorylation to be activated. In the phosphate-groove-knockin ES cells, the activation of S6K, RSK and SGK by agonists, although markedly impaired, was not abolished. PDK1 also phosphorylates the T-loop of protein kinase C (PKC) isoforms, which stabilizes these enzymes. However, in contrast to S6K, RSK and SGK, hydrophobic motif phosphorylation of these enzymes is not thought to control their activation by PDK1. Consistent with this notion, we employed appropriate PDK1-knockin ES cells to demonstrate that the hydrophobic groove of PDK1, but not the phosphate groove, is required for the stabilization of PKC isoforms. These findings provide genetic evidence that the phosphate groove of PDK1 is required for maximal activation of isoforms of S6K, SGK and RSK, but not PKC. We also found that no live births of homozygous phosphate-groove-knockin mice are observed, indicating a key role for this regulatory motif in normal development. The knockin embryos develop to a greater extent than PDK1-knockout and hydrophobic-groove-knockin embryos, which died between E9.5-E11.5. The knockin embryos are observed until E19.5 and displayed general growth retardation and craniofacial developmental defects.
Effect of water and methanol fractions on the performance of a CI engine using animal fat emulsions as fuel
Authors: Kumar Senthil M , Kerihuel A , Bellettre J , Tazerout M
Published: October 2005

The influence of water and methanol (W/M) fractions on the performance of a compression ignition engine fuelled with animal fat (obtained from duck) emulsions is studied. A single cylinder air-cooled, direct injection diesel engine developing a rated brake power output of 2.8 kW at 1500 r/min is tested using diesel neat animal fat, and animal fat emulsions with different fractions of W/M.

Results show reduced peak pressure with neat animal fat when compared with diesel. Animal fat emulsions result in increased peak pressure with increased W/M fractions. Ignition delay is quite high with neat animal fat. Increase in W/M amounts in the emulsions further increase the ignition delay. Heat release pattern shows improved combustion rates with animal fat emulsions at all W/M fractions when compared with neat animal fat.

Drastic reduction in smoke emission from 3.6 m−1 with neat animal fat to a minimum of 0.5 m−1 is achieved with the animal fat emulsion at the maximum W/M fraction. NO emission is found to be lower with neat animal fat than with neat diesel. Animal fat emulsions further reduce NO emission at all W/M fractions. Hydrocarbon and carbon monoxide emissions are also reduced significantly with animal fat emulsions at all W/M ratios when compared with neat animal fat. In general, animal fat emulsions with different W/M fractions show considerable reduction in all emissions and improvement in engine performance when compared with neat animal fat. Emulsion of 10W10M2S83 (i.e. 10 per cent of water, 10 per cent of methanol, and 2 per cent of span 83 by volume) is found to be the best among the three tested emulsions for optimum performance and emissions.
Improved momentum exchange theory for incompressible regenerative turbomachines
Authors: Yoo I S , Park M R , Chung M K
Published: October 2005

On the basis of the momentum exchange theory, an improved mathematical model is developed to analyse the complicated helical flow in regenerative turbomachines and to suggest a systematic way to design such kind of machines. The helical flow in the machines is resolved into a peripheral component and a circulatory component, and a theoretically sound method is proposed to calculate the circulatory flow velocity and slip factor, which are closely related to the machine performance. To implement the present method, the concepts of a circulatory pivot and an effectiveness of the circulatory flow are introduced. The circulatory flow loss was successfully estimated by introducing a bend-combination factor by adding four right angle bends losses. It was found that the overall head rise and the hydraulic efficiency can be accurately predicted by the proposed model equation and the present loss models. Development of the static pressure along the peripheral direction could be predicted satisfactorily.
Automatic computational fluid dynamics-based procedure for the optimization of a centrifugal impeller
Authors: Martelli F , Pazzi S , Michelassi V
Published: October 2005

A typical centrifugal impeller characterized by a low flow coefficient and cylindrical blades is redesigned by means of an intelligent automatic search program. The procedure consists of a feasible sequential quadratic programming algorithm (Fletcher, R. Practical Methods of optimization, 2000 (Wiley)) coupled to a lazy learning (LL) interpolator 1 to speed-up the process. The program is able to handle geometric constraints to reduce the computational effort devoted to the analysis of non-physical configurations. The objective function evaluator is an in-house developed structured computational fluid dynamics (CFD) code. The LL approx-imator is called each time the stored database can provide a sufficiently accurate performance estimate for a given geometry, thus reducing the effective CFD computations.

The impeller is represented by 25 geometric parameters describing the vane in the meridional and s-0 planes, the blade thickness, and the leading edge shape. The optimization is carried out on the impeller design point maximizing the polytropic efficiency with nearly constant flow coefficient and polytropic head. The optimization is accomplished by maintaining unaltered those geometrical parameters which have to be kept fixed in order to make the impeller fit the original stage. The optimization, carried out on a cluster of 16 PCs, is self-learning and leads to a geometry presenting an increased design point efficiency. The program is completely general and can be applied to any component which can be described by a finite number of geometrical parameters and computed by any numerical instrument to provide performance indices.

The work presented in this paper was done under the METHOD EC funded project for the implementation of new technologies for optimization of centrifugal compressors.
Modelling and optimization of part-flow evaporative gas turbine cycles
Authors: Yari M , Sarabchi K
Published: October 2005

The evaporative gas turbine cycle is a new high-efficiency power cycle that has reached the pilot plant testing stage. This article presents the construction of a mathematical model for thermodynamic simulation of part-flow evaporative gas turbine cycle including steam injection. The maximum deviation of predicted performance results by this model from available data in literature was 1 per cent. Then, changes in configuration of this cycle have been investigated. Configuration changes concern using feed water heater and injection of saturated vapour instead of superheated vapour to the humid air in the cycle. This investigation shows that both these strategies were in the direction of improvement of efficiency and specific work of cycles (intercooled and non-intercooled). The results obtained from this research show that using spray cooler as the intercooler in the intercooled cycle offers interesting perspectives. In addition, the optimization of part-flow evaporative gas turbine (PEvGT) cycles in the systematic manner is presented and discussed.
Open Trial of Pindolol in the Treatment of Fibromyalgia
Authors: Wood Patrick B , Kablinger Anita S , Caldito Gloria S
Published: October 2005

BACKGROUND

Evidence suggests that fibromyalgia is related to both chronic sympathetic hyperactivity and decreased levels of serotonin.

OBJECTIVE

To examine the efficacy of pindolol, a mixed serotonin (5-HT)1A presynaptic autoreceptor/β-adrenergic receptor antagonist, in the treatment of fibromyalgia.

METHODS

An open trial was conducted using 20 female patients who met the American College of Rheumatology criteria for fibromyalgia. Treatment was initiated with pindolol 7.5 mg/day and titrated to a maximum dose of 15 mg/day for a total of 90 days. Primary outcome measures were tender point analysis and the Fibromyalgia Impact Questionnaire (FIQ). Anxiety and depression were measured with the Hamilton Depression and Anxiety Scales and Beck Depression Inventory.

RESULTS

There was significant improvement in primary outcome measures, including Tender Point Count (mean ± SD, 16.3 ± 2.2 vs 12.3 ± 5.0; F = 8.9; p < 0.001), Tender Point Score (24.4 ± 5.7 vs 17.5 ± 9.4; F = 7.8; p < 0.001), and FIQ (45.3 ± 10.8 vs 35.0 ± 15.0; F = 5.6; p < 0.005). The depression and anxiety scores did not change significantly among women who completed the study, while the impact on cardiovascular parameters was clinically insignificant.

CONCLUSIONS

While the current results are encouraging, further studies are needed to determine whether pindolol might be effective in the treatment of fibromyalgia. Limitations of this study include small group size and lack of placebo control.
Incremental Effects of Concurrent Pharmacotherapeutic Regimens for Heart Failure on Hospitalizations and Costs
Authors: Skrepnek Grant H , Abarca Jacob , Malone Daniel C , Armstrong Edward P , Shirazi Farshad M , Woosley Raymond L
Published: October 2005

BACKGROUND

Inappropriate medication use in patients with heart failure (HF) presents challenges in providing optimal, evidence-based care.

OBJECTIVE

To evaluate the incremental differences of concurrent and persistent use of angiotensin-converting enzyme (ACE) inhibitors, β-blockers, loop diuretics, and digoxin on the one-year, all-cause risk of hospitalization and total healthcare costs associated with treatment of HF in patients enrolled in a managed care organization within the US.

METHODS

A retrospective database analysis was conducted spanning from January 1, 1997, to December 31, 1999. Multivariate regression methods were used to examine the association between treatment regimens and hospitalizations or costs after controlling for patient demographics and risk factors.

RESULTS

Of the 1903 patients meeting inclusion criteria, 32.3% (n = 615) received none of the 4 HF agents studied and were associated with a 2.5 times greater risk (p ≤ 0.001) of hospitalization and 43.6% higher (p ≤ 0.001) total costs compared with all other patients with HF. Comparatively, 13.9% (n = 264) utilized the HF medications investigated for at least 6 months. Of those with persistent use of ≥3 agents, approximate decreases in hospitalizations were noted of 80% (p ≤ 0.001) and total costs of 70% (p ≤ 0.001) relative to patients receiving no HF therapy.

CONCLUSIONS

A substantial portion of patients with HF may be receiving suboptimal pharmacotherapeutic care in real-world practice settings, potentially incurring large increases in hospitalizations and total costs. Quality improvement initiatives should seek to identify and manage those not being treated according to guideline recommendations.
Natalizumab for the Treatment of Multiple Sclerosis and Crohn's Disease
Authors: Keeley Kendra A , Rivey Michael P , Allington Douglas R
Published: October 2005

OBJECTIVE

To review the pharmacology, pharmacokinetics, safety, and pivotal clinical trials for natalizumab in the treatment of multiple sclerosis (MS) and inflammatory bowel disease.

DATA SOURCES

A PubMed/MEDLINE search was conducted (1966–June 2005), and information was obtained from Iowa Drug Information Services. Additional data sources included meeting abstracts, bibliographies from identified articles, and information from the manufacturer.

STUDY SELECTION AND DATA EXTRACTION

Studies and review articles examining natalizumab were evaluated. All published, randomized clinical trials evaluating natalizumab in MS and IBD were included in this review.

DATA SYNTHESIS

Natalizumab is the first drug in a new class of agents called selective adhesion molecule inhibitors. It has shown promising results in MS and inflammatory bowel disease and appears superior compared with current therapies in reducing relapse rates. However, 3 recent, confirmed case reports of progressive multifocal leukoencephalopathy (PML) create concern about natalizumab's use in combination with existing therapies or in undefined patient subgroups. Natalizumab was voluntarily withdrawn from the market in March 2005 while the drug's safety is further evaluated.

CONCLUSIONS

Although long-term efficacy and safety of natalizumab have not been established, available data indicate that it is a novel drug for patients with MS or inflammatory bowel disease. Analysis of its possible association with PML will determine the risk–benefit evaluation and eventual place in therapy for natalizumab.
Community Pharmacy–Based Pharmaceutical Care for Asthma Patients
Authors: Mangiapane Sandra , Schulz Martin , Mühlig Stephan , Ihle Peter , Schubert Ingrid , Waldmann Hans-Christian
Published: October 2005

BACKGROUND

Despite significant progress in asthma drug therapy in recent years, there has been no major change in asthma morbidity and mortality. It is still important to determine whether pharmaceutical care (PC) influences health outcomes.

OBJECTIVE

To evaluate the effectiveness of PC with regard to clinical, humanistic, and economic outcomes in adults with asthma.

METHODS

An intervention study was conducted over 12 months. At baseline, 39 community/retail pharmacies, 84 primary care physicians (general practitioners, internal specialists, chest physicians), and 183 patients (aged 18–65 y) diagnosed with asthma were included. To evaluate economic outcomes, 2 German statutory health insurance funds provided 2 years of claims data for their insured patients (n = 55). A 1:10 matching was carried out to compare the data of this intervention subgroup with those of a control group (n = 550).

RESULTS

Significant improvements were found for all humanistic outcomes (eg, asthma-specific quality of life, self-efficacy, knowledge, medication adherence). In addition, asthma severity, self-reported symptoms, peak expiratory flow, and patients’ inhalation technique improved. Increases in forced expiratory volume in 1 second and vital capacity were not significant over time. Evaluation of the insurance claims data revealed a shift toward better adherence to evidence-based therapy.

CONCLUSIONS

The study shows that PC for people with asthma has a positive impact on humanistic and, to some extent, on clinical outcomes. To determine potential economic benefits, future research should focus on patients with more severe asthma.
The Need for Routine Bleomycin Test Dosing in the 21st Century
Authors: Lam Masha SH
Published: October 2005

OBJECTIVE

To review the clinical evidence for routine use of bleomycin test dosing.

DATA SOURCES

English-language review articles, references from retrieved articles, case reports, and clinical trials were identified from a MEDLINE literature search (1966–July 2005). Key search terms included bleomycin, test dose, anaphylactic reactions, and hypersensitivity. Information from an unpublished E-mail survey, the manufacturer, and the Internet was also used.

DATA SYNTHESIS

Early clinical trials and isolated case reports suggest that bleomycin-induced acute hypersensitivity reactions occur in 1% of patients with lymphoma and <0.5% of those with solid tumors. The reactions are mainly characterized by high-grade fever, chills, hypotension, and in a few cases, cardiovascular collapse, which can lead to death. The exact mechanism of these reactions is unclear, but is thought to be related to the release of endogenous pyrogens from the host cells. Evidence does not suggest any correlation between doses and the onset or severity of the reactions. Supportive care, including hydration, steroids, antipyretics, and antihistamines, may resolve the symptoms. However, it may not completely prevent recurrences.

CONCLUSIONS

The incidence of acute hypersensitivity or hyperpyrexic reactions associated with bleomycin is very low, but the reaction is potentially fatal. Clinicians should monitor their patients for any signs and symptoms of acute hyperpyrexic reactions during bleomycin administration. Since the onset of the reactions can occur with any dose of bleomycin and at any time, routine test dosing does not seem to predict when drug reactions may occur.
Characterization of Carboxylic Acids: Identification of Their Anilide Derivatives by X-ray Diffractometry
Authors: Garska Kenneth J.
Published: October 2005

In order to extend the data available for the characterization of carboxylic acids, an x-ray diffraction technique has been used for the identification of their anilide derivatives. This technique often makes possible the identification of carboxylic acids that cannot be examined readily by other techniques such as gas chromotography and mass spectrometry. Reference x-ray diffraction patterns have been obtained for the anilide derivatives of 32 carboxylic acids containing up to 18 carbon atoms. Detailed descriptions are given for obtaining and qualitatively using the x-ray diffraction patterns of these anilides. The x-ray diffraction patterns of these anilides are unique; even closely related acids which differ only in isomeric form produce anilide derivatives which exhibit different and characteristic x-ray diffraction patterns. In the qualitative analysis of single or multicomponent carboxylic acid-containing mixtures, this x-ray diffraction technique is used either alone or with infrared spectrometric techniques.
A Computer Stabilization of Brillouin Spectrograms
Authors: Hewko R. A. D. , Torrie B. H.
Published: October 2005

The components which go to make up a Brillouin spectrometer are notoriously unstable. Traditionally, one stabilizes these components by controlling their environment and by making use of complex feedback circuits. A simpler approach to the problem of instabilities is to allow them to occur and to correct for their effects on the spectra using a minicomputer. This approach has been applied to a system consisting mainly of standard commercial components.
The Infrared and Raman Spectra of α- and β-Pinenes
Authors: Wilson H. William
Published: October 2005

The liquid phase infrared and Raman spectra of α-pinene (2,6,6-trimethyl bicyclo[3.1.1] hept-2-ene) and β-pinene (6,6-dimethyl-2-methylene bicyclo [3.1.1] heptane) have been scanned between 100 and 4000 cm−1 and the vapor phase infrared spectra of both compounds between 625 and 4000 cm−1. A number of the 72 allowed modes of the C10H16 isomers can be assigned on the basis of group frequencies.
Raman Spectra of Solid (NH4)2CrO4 and (ND4)2CrO4 Obtained by a Rotating Cell Technique
Authors: Carter Robert L. , O'Hare L. Kevin
Published: October 2005

The Raman spectra of polycrystalline (NH4)2CrO4 and (ND4)2CrO4 have been obtained by a sample rotation technique where the uncompressed solid is contained in a glass cylindrical cell. The apparatus is a commerically available sample rotator for liquids, which was modified for the described solid sampling technique. The Raman spectra of (NH4)2CrO4 and (ND4)2CrO4 are discussed in relation to their uniquely monoclinic structure, in contrast to the β-K2SO4 structure found for (NH4)2SO4 and many alkali metal chromates and sulfates. The hydrogen bonding in (NH4)2CrO4 is described, and its role in determining both the structure and the Raman spectra is discussed. The data suggest a barrier to NH4+ rotation of approximately 3.70 kcal/mol, indicating that the ammonium ions are not freely rotating on the time scale of the Raman experiment (10−13 sec).
A High Sensitivity Digital Raman Difference Spectrometer for Studies on Solutions of Biological Molecules with On-Line Computer Control of Data Acquisition and Reduction
Authors: Chrisman Ray W. , English Jim C. , Tobias R. Stuart
Published: October 2005

The design and construction of a computer-controlled Raman spectrophotometer for the determination of difference spectra among up to four samples is described. The advantages of control by a minicomputer compared to a microcomputer or a hard wired controller are discussed. Conditions for the attainment of good signal/noise ratios with aqueous solutions of nucleotides in the 1 to 25 m M range are examined for the case of excitation in the visible spectrum to minimize radiation damage. Applications to studies of dilute aqueous solutions of biological molecules are discussed. The interactions of small molecules with bio-polymers, particularly, are examined.
Smoothing and Resolution Enhancement of Photoelectron Spectra with the Aid of a Programmable Desk Calculator
Authors: Pireaux Jean-Jacques
Published: October 2005

A least-squares algorithm suitable for a small memory-size programmable desk calculator is proposed for smoothing and deconvoluting electron spectroscopy for chemical analysis spectra. Smoothing with quadratic polynomial passing through nine points is shown to be the most convenient. The same procedure is applied to compute derivatives of spectra; power and limitations of this extremely simple method are discussed, in relation to a reexamination of gold valence band spectra, revealing significant features.
A Rapid Wire-Loop Method for Determination of Lead in Paint by Atomic Absorption Spectrometry
Authors: Kubota M. , Golightly D. W. , Mavrodineanu R.
Published: October 2005

A simple, rapid method is described for the determination of lead in paint. Lead is extracted from paint chips, or liquid paint, into an acidic aqueous solution. Ten microliters of sample solution is transferred onto a platinum-rhodium wire loop, and the solvent is evaporated by placing the loop in a small resistance heater. The loop then is introduced into a premixed acetylene-air flame, and lead absorption at 283.3 nm is measured. Physical and chemical parameters affecting the accuracy and precision of the method are discussed. Accurate determinations of lead are possible for concentrations ranging from 0.1 to 1 µg/10 µl of solution. The wire loop method is adaptable to a simple screening method for analysis of paints in mobile or on-site laboratories.
A Simple and Versatile Fourier Domain Digital Filter
Authors: Betty Keith R. , Horlick Gary
Published: October 2005

A number of signal processing operations can be carried out on spectra using a digital filter based on a simple trapezoid function. The filter is applied to the Fourier transform of the spectral signal. Several signal processing examples are presented to illustrate the capabilities of this filter. These examples include filtering and diagnosis of high frequency noise on a signal, removal of fixed frequency noise, minimization of quantization noise, and differentiation and approximate deconvolution for the purpose of resolution enhancement.
Photon-Induced X-ray Fluorescence Analysis of Plain Brasses
Authors: Pandian S. , Labrecque J. J. , Preiss I. L.
Published: October 2005

An x-ray spectrometric method, using a radioisotopic radiation source, for analyzing plain brasses (binary copper-zinc alloys) has been developed. The alloys are analyzed as such without dissolving them in any solvent. Methods to correct the contribution due to CuKβ to the Kβ intensity, the difference in fluorescent intensity of the two elements under consideration, and the dead time loss are discussed. The configuration of the system is given. The results obtained by the above method are compared with those obtained using atomic absorption spectrometry and with the certified values.
Temperature Determination in an Inductively Coupled rf Plasma
Authors: Visser K. , Hamm F. M. , Zeeman P. B.
Published: October 2005

Simultaneous relative radiances of the Hβ, Hγ, and Hδ spectral lines of hydrogen were measured sequentially at various lateral positions in an inductively coupled rf argon-hydrogen plasma operated at atmospheric pressure (12 kW, 9 MHz). Measurements to take self-absorption into account were also performed. By applying an Abel integral inversion, a radial radiance profile for each line was obtained. With the two-line temperature method, simultaneous temperature profiles were obtained from each of the three line-pairs. The difference between these three sets of values and the negative values obtained for the Hγ, Hδ pair indicates that thermal equilibrium does not exist in this plasma.
Low Temperature Singlet Quenching Experiments by Heavy Atom-Containing Molecules: Anomalies in the Amount of Triplet-Triplet Absorption
Authors: Lord Gabriel , Durocher Gilles
Published: October 2005

Addition of singlet quencher molecules like bromobenzene, ethyl iodide, and dimethyl mercury to degassed solutions of anthracene and phenanthrene in EPA at 77°K leads not only to a decrease in fluorescence measured in small glassy samples, but also to an abnormal decrease in the amount of triplet state absorption observed upon flash excitation of these solutions in large volume-containing low temperature cells. It is suggested that great care should be taken in order to be sure of the perfect homogeneity in the distribution of the quencher molecules throughout the sample investigated at low temperature. It is shown that the random distribution can hardly be attained, in view of the high concentration of quenching molecules needed in these experiments, when the cooling process is slow as is the case in a large volume-containing low temperature cell.
Oil Matrix Technique for Investigation of Competitive Chemisorption and Interactions between Coadsorbed Species on Metallic Films
Authors: Sheets R. , Blyholder G.
Published: October 2005

A technique to obtain intense infrared spectra over a wide frequency range for molecules adsorbed on metal particles dispersed in a hydrocarbon medium is described. New applications of this technique to determining extents of adsorption in competitive chemisorption situations and the interactions of coadsorbed species are given. Band shifts are interpreted in terms of electronic factors for ND3 and NH3 coadsorbed with PF3 on Fe, Ni, and Cu; for H2O with BCl3 on Ni; for trimethyl phosphite with CO on V, Fe, Ni, and Cu; and for alkylamines with CO on Fe and Ni.
Spectroscopy and Metal Atom Chemistry
Authors: Ozin Geoffrey A.
Published: October 2005

In the burgeoning field of cryochemistry, analytical spectroscopy has played an important role in helping us to understand the reactions of high temperature chemical species in low temperature condensation reactions. Reactions with transition metal atoms in particular have become an important synthetic method in inorganic and organometallic chemistry. Fascinating new compounds for which there are often no alternative methods of synthesis have been obtained by this technique. The potential importance of the work in terms of catalytic applications and chemical synthesis is very great indeed. Commercial evaporators and cryogenic equipment in compact and convenient forms are now commonly available and it will not be very long before metal vapor synthesis will enter the category of a routine laboratory procedure. Even at this early stage ICI (UK), duPont de Nemours (USA) and Merck (Germany) have initiated exploratory programs in metal vapor chemistry and it is only a matter of time before industrial evaporation plants are modified for large-scale metal vapor synthesis. As the field develops it is becoming increasingly evident that the seemingly unrelated methods of the preparative cryochemist and the matrix spectroscopist are intimately related. In areas such as reaction intermediates, product identification, reaction pathways, thermodynamics and kinetics, reaction feasibility and yields matrix and preparative cryochemistry cover much common ground. An intelligent marriage of the two techniques is proving to be most fruitful. In this survey lecture I will attempt to place in perspective some of the contributions that matrix isolation spectroscopy can make to the field of metal atom chemistry. In order to do this effectively in a 60-minute lecture I will restrict the reaction chemistry to that of Cu, Ag, and Au atoms. The areas to be described will include the controlled aggregation of transition metal atoms, the synthesis and characterization of coordinatively unsaturated transition metal molecular fragments and elusive binuclear compounds, and reaction kinetics using the matrix isolation technique.
Fourier Transform Infrared Spectrophotometer for Transmittance and Diffuse Reflectance Measurements
Authors: Willey R. R.
Published: October 2005

This paper describes a new Fourier transform infrared spectrophotometer with the capability to measure diffuse reflectance (DR) from 5000 to 500 cm−1 (2 to 20 µm) in addition to the normal transmittance measurements. The instrument has a true simultaneous double beam measurement mode and a high speed single beam mode. The system also takes advantage of many data manipulation and display features due to the built-in computer and 2.5 million word storage system. One of the objectives of this work was to produce a practical instrument which includes the DR capability; another was to introduce the qualitative and quantitative measurements of DR in the infrared to the analytical community. DR has been commonly available in the visible and near ir spectrum, but until this new instrument, has not been available in the ir. A brief survey of the background and history of DR and emittance measurements in the ir is given. The design details and operation of the instrument are generally examined. Brief examples are provided for a few transmittance, trace analysis, and microsampling applications, and a variety of DR results are shown. The addition of diffuse reflectance as a tool in the infrared opens new avenues for investigation and application in many fields.
The Determination of Mo, Co, and Ni in Hydrodesulfurization Catalysts by Atomic Absorption Spectroscopy
Authors: Labrecque J. J.
Published: October 2005

An atomic absorption technique was adopted to analyze hydrodesulfurization catalysts for Mo, Co, and/or Ni. After dissolution of the catalyst by sulfuric acid and hydrofluoric acid, the analysis for Mo and Co is determined using N2O-C2H2 flames and Ni is determined using air-C2H2. It was shown that the Al (80 to 85%) in the sample from the γ-alumina support of the catalyst enhanced the Mo and Co absorption signals in the N2O-C2H2 flame while no enhancement was seen for the Ni absorption signal when the cooler air-C2H2 flame was employed. Eleven commercial catalysts with information from the manufacturers on Mo, Co, and/or Ni content were analyzed by this method. The results were also in agreement with two other activation analysis methods. The relative standard deviation ranged from 1.5 to 2.5%.
Quantitative Analysis of Styrene Monomer in Styrene/Butadiene Latexes Using Raman Spectroscopy
Authors: Wancheck Patricia L. , Wolfram Lynn E.
Published: October 2005

A simple rapid method has been developed for the quantitative analysis of styrene monomer in butadiene/styrene latexes using Raman spectroscopy. The latex samples were sealed in capillary tubes and scanned under high resolution conditions using a Spex Ramalog 1401 with a Spectra Physics 2 W argon ion laser. The Raman method involves ratioing the olefinic C=C (1632 cm−1) band of styrene monomer to the trans 1:4 C=C (1668 cm−1) band of butadiene in the butadiene/styrene polymer. Typical samples were found to have as low an unreacted styrene concentration as 0.7 wt. %. Reproducibility between samples was found to be within 0.1%. The values of residual styrene obtained by the Raman technique agreed within 0.25% with those obtained by liquid chromatography.
Noise and Finite Register Effects in Infrared Fourier Transform Spectroscopy
Authors: Foskett C. T.
Published: October 2005

Finite registers used in computations act as additional noise sources in infrared Fourier transform spectroscopy. The relationship between these noise sources and classical noise sources is examined. The impact of finite register lengths on data acquisition, computation of the fast Fourier transform (FFT), and post-FFT spectral manipulations leads to the conclusion that the minimum recommended register length is 27 bits.
Characterization of a dc Plasma as an Excitation Source for Multielement Analysis
Authors: Skogerboe R. K. , Urasa I. T. , Coleman G. N.
Published: October 2005

A commercial dc plasma has been evaluated as an excitation source for multielement spectrometric analyses. Plasma temperatures have been measured and typical excitation profiles determined. Detection limits have been determined using a direct reading spectrometer equipped for simultaneous background correction measurements. The results indicate that precise multielement analyses can be carried out at low concentration levels comparable to those that can be obtained by flame atomic absorption methods.
Emission Spectrographic Analysis of Surfaces with an Ion-Sputtering Source
Authors: Waitlevertch M. E. , Hurwitz J. K.
Published: October 2005

An ion-sputtering source was installed and evaluated as an emission spectrographic source for the analysis of metal surfaces and for the determination of in-depth concentration profiles. This source generates a direct current glow discharge in a low-pressure argon atmosphere between a hollow stainless-steel anode and the sample (the cathode) and sputters material at a controlled rate from the sample surface. The resultant spectrum of the sputtered material is recorded photographically, and the analysis is completed by conventional spectrographic techniques. The power supply of the source can be operated in either a constant dc mode or a square-wave dc mode, but better repeatability and accuracy have been achieved with the square-wave dc mode. Before any significant sputtering occurs with this source, the voltage must exceed 240 Volts, the threshold sputtering voltage. The sputtering rate increases with both source current and voltage. This source has been used for the quantitative analysis of the surface of steel products and the determination of changes in composition with depth below the surface.
Some Characteristics of Low Pressure, Sulfur, Microwave-Excited, Electrodeless Discharge Lamps
Authors: Childs Allan H. , Schrenk W. G.
Published: October 2005

Electrodeless discharge lamps (EDL) containing different sulfur compounds (elemental sulfur, H2S, SO2, ZnS, Na2S, and CS2) have been fabricated using quartz tubes (30 mm long by 8 mm i.d.) and He, Ar, Ne, Kr, or Xe as fill gases. Intensity and stability of EDL have been observed using fill-gas pressures ranging from 0.01 to 1.7 Torr at 216.9, 469.5, 545.4 (sulfur lines) and 384.0 nm (S2 band head). Data are presented showing the effects of temperature on the intensity and stability of the EDL. Optimal conditions for each sulfur compound and fill gas are given.
Raman Spectroscopy and Virus Research
Authors: Thomas George J.
Published: October 2005

A survey is given of developments leading to the application of laser-Raman spectroscopy in structural studies of viruses and model nucleoproteins. The major constituents of viruses — nucleic acid and protein molecules — exhibit Raman spectra which differ greatly from one another, both in the spectral ranges that contain vibrational frequencies of conformational interest and in the relative intensities of Raman scattering of their respective subgroups. These features, not common to the infrared spectra, allow laser-Raman spectroscopy to be exploited for the study of viral assembly and nucleoprotein interactions. Examples considered here are the RNA-containing virus MS2, the DNA-containing viruses Pfl and fd, and the complex of polylysine with DNA.
The Infrared and Raman Spectra of BaCl2 · 2H2O Powder
Authors: Jain Y. S. , Kapoor V. K. , Bist H. D.
Published: October 2005

The infrared absorption and the laser excited Raman spectra of BaCl2 · 2H2O powder have been analyzed. The force constants kH and kH governing the librational modes of H2O molecules in this crystal are also reported.
Vibrational Energies for Isotopically Substituted Water: Application to Laser Isotope Separation
Authors: Carney G. D. , Curtiss L. A. , Langhoff S. R.
Published: October 2005

Band origins of tritiated water, HTO, DTO, T2O, many of which have not been observed, are calculated with variational vibrational methods using an experimental potential function. The results are quite accurate and should aid in developing laser isotope separation procedures to remove tritium from water. The effect of dimer formation on these band origins is also investigated using the Wilson FG method with a theoretical harmonic force field and found to be important.
Ultratrace Analyses by Optical Emission Spectroscopy: The Stray Light Problem
Authors: Larson G. F. , Fassel V. A. , Winge R. K. , Kniseley R. N.
Published: October 2005

When atomic emission spectroscopy is employed for the determination of trace elements at concentrations near the detection limit, the spectral background will normally be a large fraction of the total measured signal. Precise background corrections are therefore required if accurate analyses are to be achieved. Experimental evidence is presented to document the fact that stray light may produce substantial shifts in the background signal measured with some spectrometers when the total composition of the sample changes. The data presented have been obtained with the inductively coupled plasma as an excitation source; similar effects can be expected with other excitation sources as well. Examples of various forms of stray light originating from grating defects (ghosts, near and far scatter) and defects in the design of spectrometers are presented. Various methods for the reduction, elimination or correction of stray light effects are also discussed.
Analysis of Atmospheric Particulates for Trace Elements by Optical Emission Spectrometry
Authors: Scott D. R. , Loseke W. A. , Holboke L. E. , Thompson R. J.
Published: October 2005

One thousand composited particulate samples collected by the National Air Surveillance Network in 1970 on glass fiber filters were analyzed for 24 trace elements by spark-excited direct reading emission spectrometry. After acid extraction, the lithium chloride stabilized extracts were analyzed in duplicate using a rotrode with indium as an internal standard. Interference corrections and calibration data were frequently updated during analyses by special minicomputer programs. Iron, calcium, aluminum, magnesium, zinc, and manganese were found in unused filters. Precision data on samples had a median relative standard deviation of 14% for all elements. The median spike recovery was 97%, excluding tin with 11 to 28%. Analysis of different portions of the same filters gave average concentration differences with a median of 14%. Detection limits for all elements and lead analysis by both atomic absorption and optical emission are reported. Zinc and tin data were unacceptable due to poor precision or accuracy.
Influence of an External Rotating Magnetic Field on Spectral Line Intensities
Authors: Pavlović B. , Mihailidi T.
Published: October 2005

The interaction of an external rotating magnetic field (from 0 to 4.5 mT) and a 9 A dc arc in air as a spectrochemical source was investigated. The change in spectral line intensities of Tl, Sn, Pb, Ge, Mg, Sb, Cd, Zn, and Hg, which were present as trace elements in arc burning in external rotating magnetic field, was observed. Two types of lower electrodes were used in these experiments since it was found that the form of electrode also influences the interaction on the rotating magnetic field and the arc. In one series of measurements the lower electrode was used as an anode and in the second as a cathode. Only in the case of a cathode excitation in the external rotating magnetic field were noticeable changes in spectral line intensities observed.
Emission Spectrometric Arcing Procedure with Minimal Effect of Chemical Form of Sample
Authors: Gordon William A.
Published: October 2005

This paper describes a study of matrix effects related to the chemical form of materials analyzed. The study was made using an arc in argon buffered with silver chloride. The effect of chemical form was minimal for a variety of metals, oxides, and carbides representing the most refractory compounds and thermally stable metal-containing molecules. Among these, only four of the most refractory materials known showed significant emission depressions due to incomplete volatilization in the arc system. These results are discussed in terms of vapor pressure of the solid materials placed on the anodes and dissociation reactions of the molecules in the gaseous environment.
A Laser Microphotometer for Determining Uniformity of Particulate Deposits on Membrane Filters
Authors: Kuehner Edwin C. , Cassatt Wayne A.
Published: October 2005

An apparatus for determining the uniformity of a layer of fine particles deposited on a membrane filter is described. A transmission scan of a laser beam across the filter deposit is a measure of the uniformity of the deposit layer. Quantitative estimates, with an accuracy of approximately 10%, of areal densities are inferred by calibration against reference deposits of ground orchard leaves on membrane filters.
A Discussion of Nonpolarizing Angles in Thin-Film Beam Splitters for Michelson Interferometers
Authors: Smith Donald R. , Loewenstein Ernest V.
Published: October 2005

We have investigated the polarization properties of thin-film beam splitters for a wide range of refractive indices and angles of incidence. We have found that the polarizance is zero at certain incident angles for one or two wavelengths in each cycle of the beam splitter. For any angle other than the Brewster angle, however, the polarizance varies significantly over the remainder of the usable wavelength range and at the high angles of incidence required to achieve a nonpolarized wavelength the variation is quite large.
A Computer Controlled Raman Spectrometer System
Authors: Kint Saima , Elsken Richard H. , Scherer James R.
Published: October 2005

We describe a software system and a hardware interface between a laser Raman spectrometer and a time-shared computer. This data acquisition system controls the wavelength drive of the spectrometer and the analyzer orientation using stepping motors and position sensors. With this method accurate depolarization ratios can be determined at every wavelength increment. Digitized photon counting gives good signal/noise ratios and a wide dynamic range for Raman intensity measurements. The software design permits automatic separation of isotropic and anisotropic spectra, repetitive counting periods, instant scope display of raw, reduced or integrated data, and numerous data refinement options.
Frequency Dependence of Relative Intensities and Depolarization Ratio for Resonance Raman Scattering
Authors: Chao Robert Shih-Liang , Lippincott Ellis R.
Published: October 2005

Theoretical expressions for the frequency dependence of the intensities of Raman lines in the pre-resonance and rigorous resonance Raman scattering are derived on the basis of a new approach. In this effort the main contribution to the change in polarizability is obtained from the derivative of electronic transition moment with respect to the vibrational normal coordinates. Therefore, this approach differs from previous approaches which suggested that the main contribution to the Raman intensities (polarizability derivative) comes from the derivative of electronic frequency with respect to the normal coordinate. This new approach leads to excellent agreement between the derived theoretical expressions and several recently reported experimental studies. In this paper the effective absorption frequencies and damping terms are determined from the excitation profile rather than the electronic absorption spectrum. To extend these studies to non-totally symmetric modes by considering the scattering due to nondiagonal polarizability tensor components, we have attempted to derive the depolarization ratios by calculating the contribution to the scattered intensity from the quadrupole and magnetic dipole terms. An anomalous depolarization ratio results from the angular distribution of the magnetic dipole vibration at a certain spectral location.
Analysis by Optimized Gas Chromatography/Infrared/Nuclear Magnetic Resonance Techniques
Authors: Gallaher Kenneth L. , Grasselli Jeanette G.
Published: October 2005

A method is described for obtaining infrared and proton NMR spectra of the same GC fraction from a mixture. The infrared vapor phase spectra are provided by a Norcon GC/ir instrument. Peaks of interest are then collected directly into a disposable 1.2 mm capillary for the microinsert of a Varian XL-100 probe. The versatility and power of this optimized combination are illustrated with several examples, including several where GC/MS was not specific. Raman spectra can also be obtained on the same GC fraction.
A Method to Obtain Diffuse Reflectance Measurements from 1.0 to 3.0 µm Using a Cary 17I Spectrophotometer
Authors: Gillespie James B. , Lindberg James D.
Published: October 2005

This paper describes a way to perform diffuse reflectance measurements over the 1.0 to 3.0 µm spectral interval by using a Cary 171 spectrophotometer equipped with inexpensive standard accessory cell-space integrating spheres. The method involves coating the cell-space spheres with a powder of pure grade quenched sulfur and making a minor alteration in an electronic amplifier. A spectrum of ground gypsum crystal in the 2.6 to 3.0 µm spectral region and a spectrum of a layer of hectorite clay in the 1.0 to 3.0 µm spectral region are presented to illustrate the applicability of the above technique for making diffuse reflectance measurements in the near infrared.
A Digitally Controlled Shutter System for Spectroscopy
Authors: Beenen G. , Rentner J. R. , Walters J. P.
Published: October 2005

A digitally controlled, two shutter system is described. The shutter will allow exposure times from milliseconds to hours with a jitter time of ±0.1 ms. An initial delay period before shutter opening can be set digitally, with the minimum delay being 3.4 ms.
Atomic Absorption Determination of Nickel in Heavy Crudes via Carbon Rod Atomizer
Authors: Labrecque J. J. , Galobardes J. , Cohen M. E.
Published: October 2005

A method is described for the determination of nickel in heavy crude oil by carbon rod atomic absorption spectroscopy in the parts per million range. A 5-g sample is completely dissolved to 25 ml of tetrahydrofuran (THF) stabilized with 0.1% hydroquinone and further diluted with THF. Nickel can be measured at a concentration of 0.1 ppm with a relative standard deviation of about 10% after a 100-fold dilution of the crude. The analysis by standard curve method as well as standard additions methods gave reproducible results. These results also agreed well with values obtained by conventional activation analysis. The method is relatively rapid after sample dilution.