bluuebunny/crossref_metadata_2025 huggingface dataset:
Rehabilitation at home after stroke: a descriptive study of an individualized intervention
Authors: von Koch Lena , Holmqvist Lotta Widén , Wottrich Annica Wohlin , Tham Kerstin , de Pedro-Cuesta Jesus
Published: August 2005

Objective: To describe the content of a programme involving early hospital discharge and continued rehabilitation at home after stroke.

Design: Quantitative and qualitative descriptive study of an intervention within the context of a randomized controlled trial.

Setting: Huddinge University Hospital, Stockholm, Sweden.

Subjects: Forty-one patients, moderately impaired after stroke, rehabilitated by a team of six occupational, physical, and speech and language therapists. Results: The average duration of the programme was 14 weeks, the mean number of home visits 12, and the median total time consumption 23 hours and 20 minutes, of which face-to-face contact with the patient constituted 54%. The rehabilitation process was pursued by the patient and the therapist in partnership. Supported by the team the therapists incorporated a wider domain of activities than usual and left a considerable amount of the training to self-directed activities. The most common foci of the visits were speech and communication, ADL activities and ambulation. When planning the intervention the therapists paid attention to discrepancies between the desires and abilities of the patient on the one hand and environmental demands on the other – discrepancies detected through observation of the patient in the home environment.

Conclusions: The home environment offers therapists working in a team opportunities to adopt a behaviour that enables patients with moderate neurological impairments after stroke to resume responsibility and influence over their rehabilitation process, resulting in an individualized rehabilitation programme that varies in duration, content and frequency of home visits.
Development and validation of the Nottingham Leisure Questionnaire (NLQ)
Authors: Drummond A ER , Parker C J , Gladman J RF , Logan P A
Published: August 2005

Objectives: To reduce the length of the Nottingham Leisure Questionnaire (NLQ) in order to make it more suitable for postal use, and to evaluate its test–retest reliability, sensitivity, stability and validity in relation to other measures of activities of daily living (ADL), mood and handicap.

Method: The NLQ was shortened and the response categories collapsed. Results from a previous trial which had used the NLQ were reanalysed to establish if significant group differences were maintained. The new version of the NLQ was subsequently tested for test–retest reliability on a new group of patients from the Nottingham stroke register who were asked to complete it twice. The new NLQ and other measures were sent to patients in a multicentre rehabilitation trial (TOTAL) six and twelve months after recruitment for postal completion.

Subjects: One hundred and thirty-seven consecutive patients from the Nottingham stroke register and 466 patients with a stroke in a multicentre rehabilitation trial.

Results: The original NLQ was reduced from 37 to 30 items and from five to three response categories. Data from an earlier study were reanalysed and differences between treatment groups remained. The results of a test–retest analysis using kappa showed that six items had excellent agreement, 15 good and nine fair, suggesting acceptable test–retest reliability. Results from the rehabilitation trial showed that the subjects performed all items and few additional activities were suggested. Higher NLQ scores were associated with higher subscores on the Nottingham Extended Activities of Daily Living Scale (NEADL) and lower NLQ scores with living alone and worse emotional health.

Conclusion: The NLQ has been successfully modified for postal self administration but there is potential for further development.
The need for a multidisciplinary outreach service for people with spinal cord injury living in the community
Authors: Cox Ruth J , Amsters Delena I , Pershouse Kiley J
Published: August 2005

Objective: To identify the nature and extent of perceived unmet needs of people with spinal cord injury (SCI) living in the community and to determine their preferences regarding multidisciplinary outreach service delivery.

Design: Structured telephone interviews.

Setting: Spinal Injuries Unit, Queensland, Australia.

Subjects: Sixty people with SCI living in the community were approached for interview and 54 agreed to participate.

Results: The results reflected a high need for a specialist, multidisciplinary SCI outreach service following primary rehabilitation. There were a diversity of issues faced by people with SCI. A high or very high need was reported by 31% of participants in relation to physical changes, by 24% regarding transport, by 22% for work issues and by 19% with respect to ongoing education needs. The greatest perceived barrier to needs being met was limited local specialist knowledge about SCI (81% of participants). A service model which includes access to telephone advice was endorsed by 79% of participants, and 43% supported home visiting that is available to rural and remote areas. Spinal Injuries Unit outpatient clinic appointments were also a preference for service delivery (40% of participants).

Conclusions: Trial and evaluation of the telephone as a primary medium for service delivery, and education of local service providers is recommended.
A survey of physiotherapy and occupational therapy provision in UK nursing homes
Authors: Barodawala Shabnam , Kesavan Sandeep , Young John
Published: August 2005

Background: Nursing homes in the UK are increasingly regarded as potential rehabilitation facilities for disabled older people.

Objective: To determine the current physiotherapy and occupational therapy provision to UK nursing homes.

Sample: Four hundred private nursing homes in England, Scotland and Wales were selected by stratified proportional random sampling and surveyed by postal questionnaire.

Results: The response rate for the effective sample was 346/355 (97%). Only 10% of residents were in current receipt of physiotherapy, mostly through private physiotherapists employed by the nursing homes. Occupational therapy was being provided to only 3.3% of residents.

Conclusion: Older people in nursing homes in the UK currently receive little physiotherapy and occupational therapy input and are particularly isolated from National Health Service (NHS) services.
Is Definitive Abdominal Evaluation Required in Blunt Trauma Victims Undergoing Urgent Extra‐abdominal Surgery?
Authors: Holmes James F. , Schauer Bobbie Ann , Nguyen Hien , Wisner David H.
Published: August 2005

Objectives: To evaluate the utility of routine abdominal computed tomographic (CT) scanning for abdominal evaluation of blunt trauma patients before urgent extra‐abdominal surgery. Methods: In this observational cohort study, we prospectively enrolled all blunt trauma patients at least 8 years of age presenting to the emergency department of a Level 1 trauma center who were initially considered to require urgent extra‐abdominal surgery within 24 hours of presentation. Patients were excluded if they had any of the following: 1) isolated extremity trauma, 2) signs or symptoms of intra‐abdominal injury (including systolic blood pressure <90 mm Hg; abdominal, flank, or costal margin tenderness; abdominal wall contusion or abrasion; pelvic fracture; and gross hematuria), or 3) unreliable findings on abdominal examination (Glasgow Coma Scale score <14, paralysis, or mental retardation). Clinical data were documented on a data sheet before abdominal CT scanning. Results: A total of 254 patients, with a mean (±SD) age of 32.3 (±16.1) years, were enrolled. A total of 201 patients ultimately underwent urgent extra‐abdominal surgery for the following procedures: orthopedic, 182 (91%); facial, 17 (8%); laceration, 7 (3%); vascular, 6 (2%); neurosurgical, 3 (1%); urology, 2 (1%); and ophthalmology, 1 (0.4%). Three patients (1.2%; 95% confidence interval = 0.2% to 3.4%) were found to have intra‐abdominal injuries. Two patients had splenic injuries that required only observation. One patient (0.4%; 95% confidence interval = 0% to 2.2%) underwent laparotomy. This patient sustained multiple injuries in a motorcycle crash, including splenic, kidney, and pancreatic injuries, and underwent a splenectomy. Conclusions: Abdominal CT scanning has a low yield in trauma patients whose sole indication for diagnostic abdominal evaluation is the need for general anesthesia for urgent extra‐abdominal surgery. A small percentage of these patients, however, will have important intra‐abdominal injuries such that further refinement of the recommendations for diagnostic study in this select population is needed.
Cationic cell-penetrating peptides interfere with TNF signalling by induction of TNF receptor internalization
Authors: Fotin-Mleczek Mariola , Welte Stefan , Mader Oliver , Duchardt Falk , Fischer Rainer , Hufnagel Hansjörg , Scheurich Peter , Brock Roland
Published: August 2005

Cationic cell-penetrating peptides (CPPs) have been used widely as delivery vectors for the import of molecules that otherwise do not cross the plasma membrane of eukaryotic cells. In this work, we demonstrate that the three cationic CPPs, Antennapedia homeodomain-derived peptide (Antp), nona-arginine and Tat-derived peptide, inhibit tumour necrosis factor (TNF)-mediated signal transduction. This inhibition is based on the downregulation of TNF receptors at the cell surface by induction of internalization. In contrast to TNF-dependent receptor internalization, no receptor activation occurs. The receptor downregulation is not restricted to the CPPs. Remarkably, the HIV-1 Tat protein itself also induces the internalization of TNF receptors. The dynamin dependence of the internalization, as well as the fact that epidermal growth factor receptors are also internalized, suggest a general induction of clathrin-dependent endocytosis as the mechanism of action. The significance of these findings for the use of cationic CPPs in the import of bioactive peptides is demonstrated here using a conjugate consisting of Antp and a Smac protein-derived cargo peptide. The cargo alone, when introduced into cells by electroporation, enhanced TNF-induced apoptosis by inhibiting the anti-apoptotic action of IAPs (inhibitor of apoptosis proteins). For the Antp-Smac conjugate at concentrations below 40 μM the inhibitory effect of the Antp peptide compensated for the pro-apoptotic activity of the cargo, and led to the protection of cells against TNF-mediated apoptosis. These data provide important new information for the use of cationic CPPs for the cellular delivery of bioactive molecules.
Tandem repetitive transgenes and fluorescent chromatin tags alter local interphase chromosome arrangement in Arabidopsis thaliana
Authors: Pecinka Ales , Kato Naohiro , Meister Armin , Probst Aline V. , Schubert Ingo , Lam Eric
Published: August 2005

Fluorescent protein chromatin tagging as achieved by the lac operator/lac repressor system is useful to trace distinct chromatin domains in living eukaryotic nuclei. To interpret the data correctly, it is important to recognize influences of the tagging system on nuclear architecture of the host cells. Within an Arabidopsis line that carries lac operator/lac repressor/GFP transgenes, the transgene loci frequently associate with each other and with heterochromatic chromocenters. Accumulation of tagged fusion protein further enhances the association frequency. Independent experiments with a transgenic plant carrying another multi-copy transgene also revealed, independent of its transcriptional state, unusually high frequencies of association with each other and with heterochromatin. From these results we conclude that the lac operator/lac repressor chromatin tagging system may alter the spatial chromatin organization in the host nuclei (in particular when more than one insertion locus is present) and also that loci of homologous transgenic repeats associate more often with each other and with endogenous heterochromatin than normal euchromatic regions.
Prediction of stress concentrations associated with interacting stress-raisers within aircraft design: Methodology development and application
Authors: Graham R H , Raines M , Swift K G , Gill L
Published: August 2005

In the design and manufacture of aerostructures and associated mechanical systems, situations arise where two or more stress-raisers are placed in proximity such that their associated stress fields interact. Under such circumstances, it is essential to determine accurately the resulting stress concentration effect, in order to evaluate the susceptibility of the structure to fatigue. The paper reports on new methodologies for predicting the location and magnitude of the maximum stress concentration around a range of commonly occurring two- and three-dimensional problems of feature interaction.

The background research into the impact of multiple stress-raisers in proximity is reported and new techniques for the accurate prediction of stress concentrations associated with interacting features are described. The application and implementation of the methodologies within BAE SYSTEMS are discussed and the approach developed is illustrated by means of a case study.
Active homing performance enhancement with multiple model radome slope estimation
Authors: Song T L , Lee D G , Shin S J
Published: August 2005

In this paper, a new filter structure with the interacting multiple model (IMM) algorithm for estimating both the radome slope and target states is suggested to reduce the radome induced miss distance effectively in active homing engagements of a surface-to-air missile. The proposed filter in conjunction with proportional navigation guidance is tested by a series of simulation runs in three-dimensional engagement scenarios. Simulation results show that the proposed filter structure stabilizes the missile system and gives allowable miss distance in case of large incident lag that may cause system instability in the presence of the radome slope.
Aeronautics-1903; aerospace-2003; ? ? 2103
Authors: Allen J E
Published: August 2005

The centenary of the first manned flight was a unique occasion permitting a rare opportunity to range far into both the past and the future. Most of aeronautics must inevitably be focussed on the near future and immediate actions. However, there are some very long-term underlying issues which are invisible from a day-to-day perspective, but which should not be overlooked as they can be used very often to guide decisions that might otherwise be unsound.

In Part 1, the paper reviews the major breakthroughs that have impelled aeronautics along a startling trajectory of success, with some mention of the uncertain beginnings, when even Wilbur Wright considered that all his aerodynamic theories were in a muddle. In that spirit, in Part 2, some attempts are made to anticipate possible breakthroughs that might happen in the 21st century. However, aeronautics does not stand alone. Considerations, such as other transport modes, energy substitution, non-vehicular transport, and the consequences of major global political alignments, will be reviewed in order to seek new aeronautical challenges of the future. Some other long-term, but non-aeronautical engineering, initiatives relevant to the IMechE are introduced and discussed in the appendix
A General Purpose Algorithm for Three-Dimensional Packing
Authors: Brunetta Lorenzo , Grégoire Philippe
Published: August 2005

We present a fast and efficient heuristic algorithm for solving a large class of three-dimensional packing problems with the objective of maximizing the average volumetric utilization of containers that might be of different dimensions. The algorithm is a tree-search algorithm that implicitly explores the solution space. The algorithm relies on the fact that, in practice, (i) the number of different types of objects to pack is limited and known in advance, and (ii) the number of occurrences of those objects is sufficiently high to permit use of a pattern approach to solve, at least partially, the problem. Each node of the search tree is solved using an extension of a pallet-loading heuristic developed by Morabito and Morales to generate the patterns and of a container-loading heuristic developed by Pisinger to treat the objects not packed by the pattern approach. We report on our extensive computations on a new large library of instances derived from real world applications.
Efficacy and Tolerability of Alendronate Once Weekly in Asian Postmenopausal Osteoporotic Women
Authors: Ho Andrew YY , Kung Annie WC
Published: August 2005

BACKGROUND:

Osteoporosis has become a major health problem worldwide, and the incidence is rising in Asian countries. The aminobisphosphonates are potent inhibitors of bone resorption and are currently the mainstay of treatment for postmenopausal osteoporosis. Dosing frequency will likely affect tolerability and adherence to treatment.

OBJECTIVE:

To assess the tolerability and efficacy of a once-weekly aminobisphosphonate preparation in improving bone mineral density (BMD) and bone turnover markers in osteoporotic Asian women.

METHODS:

Chinese postmenopausal women with osteoporosis were randomized to receive either alendronate 70 mg once weekly plus calcium carbonate 500 mg daily (n = 29%) or calcium carbonate 500 mg daily (n = 29%) for one year. BMD was measured by dual energy X-ray absorptiometry. Markers of bone formation and bone resorption included plasma total alkaline phosphatase and urine N-telopeptides.

RESULTS:

Treatment with alendronate 70 mg once weekly for one year resulted in significant BMD improvement of 6.1% at the spine, 5.6% at the femoral neck, and 3.5% at the total hip. There was no significant change in the BMD values in the calcium group (spine 1.4%, femoral neck −0.2%, total hip 0%). The BMD response in the alendronate group was significantly different from that in the calcium group at all time points, and the difference was detectable as early as after 3 months of treatment (ANOVA p < 0.001%). The changes remained significant after adjusting for age, age at menarche, and years since menopause (p < 0.001%). Similarly, the reductions in bone markers at 12 months were significantly different between the 2 treatment groups (plasma total alkaline phosphatase: alendronate 27.9%, calcium 5.4%; urine N-telopeptide: alendronate 55.6%, calcium 11.2%; both p < 0.001%). The alendronate regimen was well tolerated, without significant adverse events.

CONCLUSIONS:

The results confirmed that once-weekly alendronate was efficacious in increasing BMD and reducing bone turnover and was well tolerated in Asian women.
Glycemic Monitoring in Diabetics with Sickle Cell Plus β-Thalassemia Hemoglobinopathy
Authors: Kosecki Sheri M , Rodgers Philip T , Adams Martha B
Published: August 2005

OBJECTIVE:

To report a case of diabetes management in a patient with a hemoglobinopathy that caused her clinician to seek a different measure of glycemic control, fructosamine, rather than glycosylated hemoglobin (HbA1c).

CASE SUMMARY:

A 53-year-old African American woman presented with a past medical history of type 2 diabetes, hypertension, seizure disorder, rheumatoid arthritis, and sickle cell disease plus β-thalassemia. She reported fasting blood glucose values ranging broadly from 50 to 320 mg/dL, yet her HbA1c result remained steady in a low range of >6%. A measure of fructosamine returned elevated at 340 μmol/L (reference range 200–300%).

DISCUSSION:

We believe that this patient's hemoglobinopathy resulted in falsely low levels of HbA1c, and we substantiate this interpretation with the patient's self-monitored blood glucose values from home that appeared higher and inconsistent with the HbA1c results. Although few reports on using the measure of fructosamine appear in the literature, this patient's high fructosamine result supports fructosamine as the more appropriate measure of glycemic control.

CONCLUSIONS:

Serum fructosamine levels may be considered as an appropriate laboratory measurement when monitoring long-term glycemic control in patients with type 2 diabetes mellitus and sickle cell disease.
Parathyroid Hormone (1–84) and Treatment of Osteoporosis
Authors: Shrader Sarah P , Ragucci Kelly R
Published: August 2005

OBJECTIVE:

To present the chemistry, pharmacology, and pharmacokinetics of parathyroid hormone (PTH) (1-84%) and review the available clinical trials that evaluate its efficacy and safety; clinical applicability of this agent and its relationship to other Food and Drug Administration (FDA)–approved medications for treatment of osteoporosis are also discussed.

DATA SOURCES:

A MEDLINE search (1996–December 2004%) was completed, along with a review of information obtained from the manufacturer, NPS Pharmaceuticals. Key search terms included parathyroid hormone, PTH (1–84%), and ALX 111.

STUDY SELECTION AND DATA EXTRACTION:

Studies were selected based on their relevance and availability. Pertinent information, including objectives, design, demographics, outcomes, adverse events, dosing strategies, and therapeutic controversies, was extracted.

DATA SYNTHESIS:

PTH (1-84%) is being developed for treatment of osteoporosis. Recent studies have shown that, when administered intermittently as a subcutaneous injection, PTH (1-84%) produces an increase in bone mineral density and prevents vertebral fractures. The fact that this agent contains the C-terminal region of PTH may differentiate it from PTH (1-34%), teriparatide, which is approved by the FDA for treatment of osteoporosis. Further trials are necessary to determine the role of PTH (1-84%) in combination with other treatments for osteoporosis and/or the order in which PTH (1-84%) is given with these other agents. There are currently no comparative trials with other osteoporosis treatment modalities.

CONCLUSIONS:

PTH (1-84%), when given intermittently as a subcutaneous injection, appears to be a safe and efficacious treatment option for osteoporosis. Further trials are needed to determine its specific place in therapy compared with other treatment options.
IR Emission Spectroscopy of Molten Salts and other Liquids Using Thick Samples as Reference
Authors: Hvistendahl J. , Rytter E. , Øye H. A.
Published: August 2005

The IR emittance of liquids relative to a blackbody is dependent on the reflectivity at the surface of the sample. This dependency leads to distortions in the bandshapes except when the absorption coefficient or the sample thickness is very low. The use of an opaque (i.e. very thick) sample as a reference eliminates the distortions in the bandshapes. A new emittance ε* = (emission of a thin sample)/(emission of an opaque sample) has been introduced. A theoretical analysis as well as experimental work on chloroaluminate melts demonstrate that the emittance ε* gives a better representation of the ideal sample property of interest, i.e., the internal transmittance of the sample, than the usual emittance with a blackbody as a reference.
The Use of a Microarc Atomizer for Sample Introduction into an Inductively Coupled Plasma
Authors: Keilsohn J. P. , Deutsch R. D. , Hieftje G. M.
Published: August 2005

The use of a microarc atomizer as a device for microsample introduction into the inductively coupled plasma (ICP) is described. The microarc, a high-voltage, low-current, pulsating dc discharge, efficiently vaporizes desolvated, discrete microvolumes of sample solution into the plasma. The microarc-ICP combination exhibits relative detection limits and working curves comparable to those of other methods of sample introduction but functions with sample volumes in the 0.5 to 1.0 μl range. Matrix and ionization interference effects are absent or trivially overcome. Computer control of the instrument adds simplicity of operation.
Long Path Length Samples in Thermal Lens Calorimetry
Authors: Carter C. A. , Harris J. M.
Published: August 2005

Laser-induced thermal lens calorimetry as applied to small absorbance determinations has traditionally relied upon the approximation that the sample behaves optically as a thin lens. The choice of a cell length which is not ideal for theory may be necessary for increased sensitivity. Two models for treating long samples of variable absorbance and enhancement are presented. The simpler of these is based on an approximation that such samples will behave according to the integrated position dependence of a thin lens. A more complex model, requiring numerical evaluation, includes the effects of sample refractive index and lens element coupling. The numerical model is verified experimentally and used to establish the limits of accuracy of the thin lens and integrated position dependence models. The consequences of using long path length samples in analytical thermal lens measurements are discussed in light of the numerical model results.
Processor Controlled Multichannel Microdensitometry for Gas Electron Diffraction Patterns
Authors: Paul David W. , Ewbank John D. , Benston O. Joel , Schäfer Lothar
Published: August 2005

The design of a novel type of densitometer for evaluating photographic plates from gas electron diffraction is described. A commercially available linear diode array has been interfaced to a PDP-11/23 minicomputer via the DRV11 parallel interface. The diffraction pattern from a photographic plate is optically focused onto a solid state linear photodiode array. The position of each diode in the array provides the radial location information and the radial intensity of each diode is digitized with 14-bit resolution. Software development provides for control over the scan parameters for the array as well as for on-line manipulation of the collected data. The new instrument thus retains the advantages of digital data filtering described in a previous procedure, but allows for faster data recording since the total pattern is determined in one scanning measurement without the mechanical stepping process which is needed in single channel instruments to move the diffraction pattern through the measuring beam. Rapid acquisition of data with on-line transgeneration should prove to be valuable in the application of the new procedure as a real time data acquisition system for gas phase electron diffraction without photographic intensity recording.
Vibrational Spectral Studies of Solutions at Elevated Temperatures and Pressures. IV. Raman Spectra of Aqueous Zinc Nitrate Solutions
Authors: Irish D. E. , Jarv T.
Published: August 2005

Raman spectra of 5.196 m aqueous zinc nitrate solution have been measured at a pressure of 11 MPa and temperatures ranging from 25 to 300°C. A band at 386 cm−1, assigned to the hexaaquazinc(II) cation, decreases in intensity and increases in freqeuncy as the temperature rises. These observations are consistent with the replacement of water molecules in the primary solvation shell of Zn2+ by a nitrate ion. Changes in the spectrum of nitrate ion support this interpretation. Evidence is also presented which suggests that the octahedral configuration around Zn2+ is being changed to a tetrahedral configuration. Estimates are made of the populations of inner sphere and outer sphere nitrate; from the plots of log Qm vs 1/ T estimates are made of ΔH and Δ S for the ion association. The plots are remarkably linear over 275 degrees of temperature.
“Quantitative” Electron Probe Analysis of Low-Atomic-Number Samples with Irregular Surfaces
Authors: Kiss Klara
Published: August 2005

The quantitative electron probe analysis on irregular surfaces via the two-voltage technique was assessed for light elements. This analysis can be performed without the knowledge of the local tilt angle, i.e., the take-off angle. Data are presented of compositions determined on crystal facets with widely varied orientations with respect to the detector. A range of model compounds and commercial products was investigated with special emphasis on those consisting of low-atomic-number elements. The usefulness of the technique, its disadvantages, and limitations are critically evaluated. The precision and accuracy obtainable in routine laboratory work are quantified and the effect of the selection of the accelerating voltage pairs and magnification is discussed.
Fourier Transform Reflectance Spectrometry between 8000 cm−1 (1.25 μm) and 800 cm−1 (12.5 μm) Using an Integrating Sphere
Authors: Richter W.
Published: August 2005

Spectral measurements of the directional hemispherical reflectance of samples exhibiting variant reflection behavior were performed in the near and mid infrared spectral region using the integrating sphere method. The main components of the experimental setup were a sphere with a diffuse gold coating and a commercial Fourier transform spectrometer for the spectral analysis of the radiation incident on and reflected by the sample which is located in the center of the sphere. The capability of the device to measure absolute reflectances was tested with polished slices of high purity silicon and germanium, the reflectances of which can be calculated from the refractive indices. Agreement between the measured and calculated values was found to be within 0.01. Diffuse reflectance standards are not yet available in the infrared. The uncertainty of absolute reflectance measurements is estimated to be ±0.02. Several examples of chemical and technical applications are presented. A relatively low spectral resolution, 16 cm−1, was used to keep the measurement times short, within the range of a few minutes, thereby minimizing signal drifts. Higher resolution, sometimes necessary for special purposes in chemical analysis, can be attained by longer measurement times. No extensive sample preparation and adjustment is necessary besides the choice of the desired angle of incidence.
Solute 13C Nuclear Magnetic Resonance Spectrometric Investigation of Acetonitrile-Tetraalkylammonium Salt Interactions
Authors: Dando Neal R. , Gold Harvey S. , Dybowski Cecil
Published: August 2005

Carbon-13 nuclear magnetic resonance spectrometry is used to observe changes in the spin-lattice relaxation time ( T1) of the alkyl chain carbons of symmetric tetraalkylammonium salts ( R4N+) X− in acetonitrile as a function of salt concentration in the range from 0.25 to 1.4 M. The T1 values of the alkyl chain carbons are observed to be differentially sensitive to salt concentration, the sensitivity being greatest at the α carbon position. These observations suggest accessibility of the cation nitrogen to solvent molecules and changing microviscosity about the salt molecule.
An HF-Resistant Sample Introduction System for the Inductively Coupled Plasma
Authors: Barnes Ramon M. , Mahanti Himansu S.
Published: August 2005

A sample introduction system constructed of materials completely resistant to HF was developed for analysis of HF-containing samples. A machined graphite injector tube, polytetrafluoroethylene (PTFE) spray chamber, and cross flow nebulizer containing PTFE capillaries were employed. The arrangement is completely compatible with commercial ICP systems and can be interchanged readily. The nebulizer efficiency and memory effect were studied and compared with a conventional system. Analysis of silicon in commercial HF acid was performed.
Laser-Induced Matrix Isolation Fluorescence Spectrometry of Methyl and Methoxyl Derivatives of Benzo[a]pyrene
Authors: Conrad Vincent B. , Wehry E. L.
Published: August 2005

The narrow bandwidth radiation of a tunable dye laser is used to excite selectively the quasilinear absorption bands exhibited by polycyclic aromatic hydrocarbons (PAH's) isolated in vapor-deposited n-alkane matrices at 15 K. The analytical utility of matrix isolation Shpol'skii fluorometry for the resolution of multicomponent PAH samples is investigated, using nonpolar derivatives of benzo[ a]pyrene as prototypes. Quantitative aspects, including the absence of aggregation and energy-transfer phenomena, also are discussed.
Monitoring the Heterogeneous Reaction of LiH and LiOH with H2O and CO2 by Diffuse Reflectance Infrared Fourier Transform Spectroscopy
Authors: Smyrl N. R. , Fuller E. L. , Powell G. L.
Published: August 2005

Measurement of the reaction of water vapor and carbon dioxide with lithium compounds such as LiH and LiOH has been carried out in situ using diffuse reflectance infrared Fourier transform (DRIFT) Spectroscopy. The bakeable high-vacuum cell, based on a modification of a commercial diffuse reflectance infrared cell is described along with means for controlling the gaseous and thermal environment.
Host Materials for Laser-Excited Fluorescence of Lanthanide Probe Ions
Authors: Porter Laura C. , Akse James R. , Johnston Murray V. , Wright John C.
Published: August 2005

An extensive study has been made of a wide range of materials to evaluate their suitability as hosts for laser-excited site selective fluorescence methods using rare earth probe ions. They are evaluated for their suitability in both direct measurements of fluorescent ions incorporated into their lattices and indirect measurements where a nonfluorescent ion is associated with a fluorescent probe ion. The association can occur because the two ions are charge compensating each other or because the nonfluorescent ion enters a lattice of fluorescent probes. These experiments have shown that probe ion methods reveal a great deal more complexity that is present at the microscopic level and cannot be measured by conventional methods. This complexity can be associated with phase heterogeneity, solid state defect equilibria, or nonstoichiometry of individual phases. Probe ion methods promise to provide a new tool to characterize such materials. This complexity prevents most of the materials from being applicable for trace ion analysis because of the sensitivity to environmental interferences. Some of the materials, however, do not exhibit this sensitivity and are consequently suitable for direct measurements. In particular, it is shown that CaO and ThO2 are good matrices which have little interference for lanthanide analyses.
T1, Nuclear Overhauser Effects Measurements in 13C NMR Spectroscopy: Analytic Relations for Short Equilibration Delays
Authors: León Vladimir
Published: August 2005

Analytic relations that describe magnetization as a function of time are given for several dynamic nuclear Overhauser effects (NOE) experiments. They allow the extraction of spin-lattice relaxation times ( T1) and NOE (η) from a three-parameter fitting of experimental data. These results are valid even for short equilibration delays if the saturated protons have a much shorter relaxation time than the observed 13C. A simple pulse sequence that combines a progressive saturation experiment with gate decoupling is proposed for measuring T1 and η values. The calculated η values are a good approximation even for short equilibration delays without any restrictive assumptions about relaxation times of the nuclei involved.
Teflon Slurry Nebulizer for Atomic Analysis
Authors: Wichman M. D. , Fry R. C. , Mohamed N.
Published: August 2005

A Teflon version of the clog-free Babington slurry nebulizer is presented. The updated design is free of contamination, is more durable, corrosion-resistant, and adjustable, and is easier to construct and repair than the previous design used for the direct slurry atomization method of analyzing solid tissues. Wettability of the Babington nebulizer surface does not appear to be important. The new nonwettable Teflon Babington slurry nebulizer yields the same aerosol median droplet diameter, droplet size distribution, total aerosol mass output rate, and final flame atomic absorbance as the previous wettable metal nebulizer of otherwise identical design and construction.
Reevaluation of Type I Diamonds for Infrared and Raman Spectroscopy in High-Pressure Diamond Anvil Cells
Authors: Wong P. T. T. , Klug D. D.
Published: August 2005

Types Ia, IIa, and IIb diamonds have been compared for their use as anvils in infrared and Raman high-pressure spectroscopy. In the mid-infrared region above 2700 cm−1, type Ia diamonds have better transmission than type IIa diamonds. In the far-infrared region between 600 and 300 cm−1 type IIa diamonds have in general better transmission than type Ia but at lower frequencies the transmissions are comparable. Type IIa diamond anvils, which have been tested for their use in Raman spectroscopy throughout the whole vibrational region and showed large fluorescence in this region when 514.5 nm laser excitation was used, yielded in general extremely low fluorescence with 363.8 nm excitation thus making them ideal for Raman spectroscopy with ultraviolet lasers.
Applications of High-Resolution Carbon-13 Nuclear Magnetic Resonance Spectroscopy to Solid Polymers
Authors: Havens John R. , Koenig Jack L.
Published: August 2005

Systematic research concerning synthetic polymers requires an understanding of molecular-level influences on macroscopic behavior. Chemical structure, morphology, orientation, and chain dynamics, which are known to have important effects on bulk material properties, have all been characterized by various forms of molecular spectroscopy. Despite such efforts, we do not have a complete understanding of the relationship between macroscopic and microscopic properties. Two general problems remain: (1) the requirement of special sample preparation for many types of spectroscopy; and (2) the limited scope of common spectroscopic techniques. Differences in sample preparation, variations in sensitivity, and ambiguities in interpretation combine to complicate the study. Recently developed NMR techniques for high-resolution in solids have demonstrated the potential to solve such problems in many cases. This review focuses on the high-resolution NMR techniques developed for 13C, the nucleus of most general interest for organic polymers. The experimental procedures are explained briefly and the provision of new information in various areas of polymer science by 13C NMR solids is discussed. Specific examples are used and some indication of future potential is presented.
Micro-High Performance Liquid Chromatography-Inductively Coupled Plasma Combination Technique in Analysis of Organometallic Compounds
Authors: Jinno Kiyokatsu , Tsuchida Hiroyuki , Nakanishi Shoji , Hirata Yukio , Fujimoto Chuzo
Published: August 2005

The combination technique of micro-high performance liquid chromatography and inductively coupled plasma atomic emission spectrometry (micro-HPLC-ICP) is demonstrated in the separation of organometallic compounds. Problems relating to the interfacing between micro-HPLC and ICP-atomic emission spectrometry could be eliminated by utilizing the simple interfacing devices in both reversed and normal phase LC modes.
Fourier Transform Infrared Analysis of the Ammoxidation of 4-Methylthiazole over a Metal Oxide Catalyst
Authors: Saperstein David D.
Published: August 2005

The gaseous products of the reaction of 4-methylthiazole (4-MT), air, 14NH3, and 15NH3 have been analyzed by on-line Fourier transform infrared spectroscopy. The products observed, including those due to partial and full oxidation, account for 95 to 98% of the starting 4-MT. Estimates of the activation energy (20 kcal/mol) and the excess heat due to combustion (350 kcal/mol/mol of 4-MT combusted) have been calculated. In addition, we have observed an unexpected reaction that is formally bimolecular in 4-MT.
An Alternate Approach to Background Correction in Atomic Absorption Spectrometry
Authors: Siemer Darryl D.
Published: August 2005

An alternate approach to implementing the background correction method originally proposed by Smith and Hieftje has been developed. Its novel feature is that only a single, short duration, high current hollow cathode lamp power pulse is used per measurement cycle. The light from the lamp is measured at the beginning and end of each current pulse after Lorentz line broadening and self-reversal have had time to fully develop. The difference between the absorbance signals observed at the two different sampling intervals is not influenced by either continuum absorption or light-scattering error signals. This approach is simple to implement, uses only standard light sources, possesses the same advantages relative to the conventional auxiliary continuum source lamp method of background correction as does the Smith and Hieftje approach, and has the added feature that all light measurements are made when the source lamp emission is very intense with respect to signals from extraneous light sources.
The Raman Microprobe: A New Analytical Tool for Studying Solid Phase Reactions
Authors: Dhamelincourt M. C. , Dhamelincourt P.
Published: August 2005

Vibrational Raman spectroscopy has already been used to study reactions in the solid state. However, until now, this technique provided only an overall indication of the reaction. With the development of Raman microprobe, it is now possible to identify positively, at the microscopic scale, the various molecular species appearing at the interface between reactants. The reaction between copper sulfate (CuSO45H2O) and lead oxide (αPbO) at ambient temperature is used as an illustration.
Fiber Optic Signal Transmission to Reduce Radio-Frequency Interference from a High-Voltage Spark Source
Authors: Barnhart Steven G. , Walters John P.
Published: August 2005

The incorporation of fiber optic signal transmission into a high voltage spark discharge experiment to reduce radio-frequency interference is described. Electrical isolation and the elimination of ground loops provided by the fiber optic links allow the use of sensitive CMOS computer logic in control of an electrically noisy spark source experiment. Circuit schematics are given and performance with three optical fiber cable types is described.
The Determination of Hydroxyl Groups in Coal by Fourier Transform Infrared and 13C NMR Spectroscopy
Authors: Snyder R. W. , Painter P. C. , Havens J. R. , Koenig J. L.
Published: August 2005

Fourier transform infrared spectroscopy and solid state 13C NMR spectroscopy have been used to measure the hydroxyl groups in coal. The methodology depends upon measuring the intensities of bands and resonances assigned to the products of acetylation reactions. In the infrared three separate bands, assigned to acetylated phenolic OH, alkyl OH, and NH groups, can be identified. In NMR, we used the methoxy carbon to determine the total OH. Spectroscopic measurements demonstrate that not only does the total OH content of coals but also the individual types of OH groups vary systematically as a function of rank. The proportion of phenolic to alkyl OH is approximately constant for the coals used in this study.
Target Factor Analysis of the Ultraviolet Spectra of Unresolved Liquid Chromatographic Fractions
Authors: McCue Matthew , Malinowski Edmund R.
Published: August 2005

Target factor analysis error criteria are applied to the UV spectra of unresolved liquid chromatographic fractions. The method is used not only to determine the number of components contributing to an unresolved chromatographic peak but also to individually verify the presence of suspected components without requiring any knowledge of the other components. An actual experimental example is presented using mixtures of o-xylene, ethylbenzene, and p-xylene. Factor analysis criteria are used to indicate which one of the fractions contains a UV-absorbing impurity(ies).
A New Background-Correction Method for Atomic Absorption Spectrometry
Authors: Smith S. B. , Hieftje G. M.
Published: August 2005

A new method is described and tested for background correction in atomic absorption spectrometry. Applicable to flame or furnace atomizers, the method is capable of correcting backgrounds caused by molecular absorption, particulate scattering, and atomic-line overlap, even up to an absorbance value of 3. Like the Zeeman approach, the new method applies its correction very near the atomic line of interest, can employ single-beam optics, and requires no auxiliary source. However, no ancillary magnet or other costly peripherals are required and working curves are single-valued. The new technique is based on the broadening which occurs in a hollow-cathode spectral line when the lamp is operated at high currents. Under such conditions, the absorbance measured for a narrow (atomic) line is low, whereas the apparent absorbance caused by a broad-band background contributor remains as high as when the lamp is operated at conventional current levels. Background correction can therefore be effected by taking the difference in absorbances measured with the lamp operated at high and low currents. The new technique is evaluated in its ability to correct several different kinds of background interference and is critically compared with competitive methods.
Quantitative Determination of Deuterium in Laser Fusion Targets by Inverse Raman Spectroscopy
Authors: Daigneault Gregory R. , Morris Michael D. , Schneggenburger Roger G.
Published: August 2005

Quantitative measurements of deuterium partial pressures in laser fusion targets are made by inverse Raman spectroscopy. Attenuation of atmospheric nitrogen inverse Raman signals is used for standardization of the system. This technique allows calibration curves to be made with long path gas cells. The measurements are accurate to ±20%.
A Design of Raman Spectrograph for Optical Activity and Normal Raman Measurements
Authors: Polavarapu P. L.
Published: August 2005

A multipurpose Raman spectrograph employing a diode array detector and optics for collecting scattered light in two orthogonal scattering planes is described. Raman spectra representing the performance of the instrument are presented.
Role of Protein Phosphatases in Estrogen-Mediated Neuroprotection
Authors: Yi Kun Don , Chung Jaegwon , Pang Priscilla , Simpkins James W.
Published: August 2005

The signaling pathways that mediate neurodegeneration are complex and involve a balance between phosphorylation and dephosphorylation of signaling and structural proteins. We have shown previously that 17β-estradiol and its analogs are potent neuroprotectants. The purpose of this study was to delineate the role of protein phosphatases (PPs) in estrogen neuroprotection against oxidative stress and excitotoxicity. HT-22 cells, C6-glioma cells, and primary rat cortical neurons were exposed to the nonspecific serine/threonine protein phosphatase inhibitors okadaic acid and calyculin A at various concentrations in the presence or absence of 17β-estradiol and/or glutamate. Okadaic acid and calyculin A caused a dose-dependent decrease in cell viability in HT-22, C6-glioma, and primary rat cortical neurons. 17β-Estradiol did not show protection against neurotoxic concentrations of either okadaic acid or calyculin A in these cells. In the absence of these serine/threonine protein phosphatase inhibitors, 17β-estradiol attenuated glutamate toxicity. However, in the presence of effective concentrations of these protein phosphatase inhibitors, 17β-estradiol protection against glutamate toxicity was lost. Furthermore, glutamate treatment in HT-22 cells and primary rat cortical neurons caused a 50% decrease in levels of PP1, PP2A, and PP2B protein, whereas coadministration of 17β-estradiol with glutamate prevented the decrease in PP1, PP2A, and PP2B levels. These results suggest that 17β-estradiol may protect cells against glutamate-induced oxidative stress and excitotoxicity by activating a combination of protein phosphatases.