bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between osteoporosis and otosclerosis in women
Authors: Clayton Amy E. , Mikulec Anthony A. , Mikulec Katharine H. , Merchant Saumil N. , McKenna Michael J.
Published: September 2004

Similarities between osteoporosis and otosclerosis have been noted, including a similar association with the COL1A1 gene. Herein, the authors explore the possible clinical relationship between these two common disorders of bone. In this retrospective study, the medical charts of 100 women aged 50 through 75 years who had undergone stapedectomy for otosclerosis were reviewed and the prevalence of osteoporosis in these women was noted. Similarly, the prevalence of osteoporosis was determined in a control group of 100 women aged 50 to 75 years with presbycusis. Fifteen of 100 women with otosclerosis had a concomitant diagnosis of osteoporosis as compared with four of 100 women with presbycusis, yielding a significant clinical association (p = 0.007) between otosclerosis and osteoporosis. This study suggests an association between otosclerosis and osteoporosis, providing impetus and justification for future prospective clinical studies and related research.
Canalplasty for severe external auditory meatus exostoses
Authors: Sanna M. , Russo A. , Khrais T. , Jain Y. , Augurio A.M.
Published: September 2004

Exostoses of the external auditory meatus is a well known condition which infrequently requires surgical correction. However, the stenosis caused by severe exostosis can affect quality of life considerably and may require surgical intervention. Canalplasty, in such a situation, is a valid and effective management option. In our series the commonest indication for surgery was recurrent otitis externa. The detailed surgical technique is described and a retrospective analysis of 65 such procedures is presented. There were only two significant complications, both post-operative stenosis, requiring further corrective surgery. In conclusion, canalplasty for the exostosis of the external auditory meatus is a safe surgical option.
Endoscopic stapling of pharyngeal pouch
Authors: Sen P. , Bhattacharyya A.K.
Published: September 2004

The relatively new technique of endoscopic stapling in the surgical management of pharyngeal pouch has gained widespread popularity over the last few years. The technique seems to be the procedure of choice as it is easier and quicker to perform and has a lower morbidity compared with open techniques. We present here an overview of the current evidence provided by a literature search performed by Ovid MEDLINE on literature published between January 1993 and May 2003 on endoscopic stapling of pharyngeal pouch. Several case series have been reported on various aspects of the surgery. The modifications in technique, peri-operative care, success rate, complications and recurrence are summarized, based on observational analytical case series. There were no randomized controlled trials comparing this approach to any other endoscopic or open surgical techniques for pharyngeal pouch.
Endoscopic dacrocystorhinostomy: long-term results and evolution of surgical technique
Authors: Durvasula V.S.P. , Gatland D.J.
Published: September 2004

This study evaluated the long-term results of endoscopic dacrocystorhinostomy (DCR) performed as a day-case procedure under local anaesthesia. It assessed the patient satisfaction with the procedure by retrospective review and a questionnaire survey.

Seventy patients were referred for endoscopic DCR to the senior author between 1997 and 2000. A success rate of 92 per cent was achieved at three months and it was possible to perform 85 per cent of cases under local anaesthetic; 91 per cent were discharged on the same day. Long-term follow up by postal survey revealed that the watering eye had improved following surgery in 83 per cent (follow up range = eight to 66 months; mean = 28.6 months). Eighty-eight per cent were satisfied with the tolerability of the procedure under local anaesthesia.

The authors describe changes in technique, which evolved with their experience of the procedure. Endoscopic dacrocystorhinostomy can be performed safely and successfully as a day-case procedure under local anaesthesia with excellent results and with great satisfaction to the patients.
Somatostatin analogues have no role in the treatment of advanced differentiated thyroid cancer
Authors: Alhamarneh O. , Murphy J. , Atkin S.L. , England R.J.A.
Published: September 2004

Somatostatins are neuropeptides that have a downregulatory effect on various physiological processes. Their use in the management of certain endocrine tumours is well recognized. Their use in thyroid cancer is not established, although there is some evidence to suggest that they have a role in advanced metastatic disease. We report a case of a patient with advanced metastatic follicular thyroid cancer which demonstrated strong octreotide uptake with reduced avidity for I131. Treatment with the somatostatin analogue octreotide, however, failed to achieve a significant response. We feel this case is important as it suggests that although octreotide provides a useful further imaging modality in differentiated thyroid cancer, it has no therapeutic role.
Tracheal haemangioma: case report
Authors: Madhumita K. , Sreekumar K.P. , Malini H. , Indudharan R.
Published: September 2004

A case of lobular capillary haemangioma of the trachea is presented. The patient gave a history of foreign body sensation in the throat and multiple episodes of haemoptysis. The chest X-ray was normal. A spiral computed tomograph (CT) with three-dimensional reconstruction revealed a small tracheal mass in the antero-lateral wall of the trachea, which was excised by endoscopy. The histopathological diagnosis was lobular capillary haemangioma, a rare, benign tumour of the trachea. A high index of suspicion with the spiral CT finding was responsible for early diagnosis of the tumour.
Bony overgrowth onto fixture component of a bone-anchored hearing aid
Authors: Sunkaraneni V.S. , Gray R.F.
Published: September 2004

An eight-year-old boy with Treacher Collins syndrome was fitted with a bone-anchored hearing aid. The audiometric result was excellent. Two years later, the abutment began to loosen and could not be tightened. It was thought that a new fixture would be required, with loss of use of the aid for three months. At surgery, bone was found to be growing over the hexagonal joint between fixture and abutment. A simple and rapid solution to this problem is described.
Granuloma annulare presenting as multiple nodules on the pinna
Authors: Raghava N. , Mitchard J.R. , Youngs R.P.
Published: September 2004

Granuloma annulare is a benign, idiopathic, inflammatory dermatosis characterized clinically by dermal papules and annular plaques. We describe the case of a 40-year-old man who presented with a long history of multiple nodules on the left pinna. Histological examination revealed the typical necrobiotic granulomas of granuloma annulare. The condition predominantly affects the extremities of children and young adults; cases involving the pinna are extremely rare.

Nodular lesions are common in otolaryngological practice, and this case illustrates the need for careful clinical assessment and appropriate biopsy in diagnosing lesions of the outer ear
Frontal sinus obliteration
Authors: Murphy J. , Jones N.S.
Published: September 2004

This article highlights the indications for frontal sinus obliteration and suggests some intra-operative points to aid the surgeon in performing the operative procedure. It also reiterates the three principal points that need to be followed. There must be:

(1) Meticulous removal of all visible mucosa and the inner bony cortex of the sinus wall.

(2) Permanent occlusion of the nasofrontal duct.

(3) The correct choice of material for the obliteration.
Long-term outcome of modified radical mastoidectomy
Authors: Mukherjee Payal , Saunders Nicholas , Liu Richard , Fagan Paul
Published: September 2004

The primary aim of treatment of cholesteatoma is to attain a dry, safe, stable ear, free of disease. Maintaining or improving hearing is important but the pursuit of a hearing result should not compromise this primary aim. This study reviews the long-term outcome of 133 patients, suffering from advanced disease, who underwent modified radical mastoidectomy between 1995 and 2000. Of these, 49 per cent had had previous mastoid surgery elsewhere. A dry, waterproof ear was attained in 95 per cent of patients. In 77 per cent of patients, hearing was unchanged or improved. In this period, there were two cases of significant post-operative loss in bone conduction, including one dead ear secondary to suppurative labyrinthitis. There were epithelial pearls on follow up in two per cent. These results indicate that when properly performed, modified radical mastoidectomy provides safe surgical access and clears disease with low recurrence rates while mostly maintaining or improving hearing.
Increasing annual incidence of vestibular schwannoma and age at diagnosis
Authors: Stangerup Sven-Eric , Tos Mirko , Caye-Thomasen Per , Tos Tina , Klokker Mads , Thomsen Jens
Published: September 2004

During the last 26 years the annual number of diagnosed vestibular schwannomas (VS) has been increasing. The aim of this study is to describe and analyse this increase. Since 1976, 1446 new cases of VS have been diagnosed at the authors’ centre. Special focus was on the age at diagnosis, the localization and the size of the tumour. The size of the tumour was registered as either intrameatal or with the largest extrameatal diameter. The annual number of diagnosed VS has increased from 26 in 1976 to 101 in 2001. The size of the diagnosed tumours has decreased from a median of 35 mm in 1979 to 10 mm in 2001. In the first years large and giant tumours dominated, in contrast to recent years in which intrameatal and small tumours dominated. The median age at the time of diagnosis has been almost unchanged through the period (median 55 years). If the decreasing size of the tumour and the increasing incidence of VS can be explained only by earlier diagnosis and easier access to magnetic resonance (MR) scanning it should be expected that the median age at the time of diagnosis would decrease simultaneously. In this study, the median age at the time of diagnosis has been almost unchanged throughout the 26-year period. This paradox can be explained by the fact that, with easier access to MR scanning, the examination has been offered also to elderly patients, in whom the small and intrameatal tumours dominate.
Diurnal variation and age-related changes of bone turnover markers in female Göttingen minipigs
Authors: Tsutsumi H. , Katagiri K. , Morimoto M. , Nasu T. , Tanigawa M. , Mamba K.
Published: September 2004

We investigated diurnal variation and age-related changes in bone turnover markers in female Göttingen minipigs. Ten females, 6–9 months of age, were used for confirmation of diurnal variation. Blood was collected at 3 h intervals for 24 h, and bone-specific alkaline phosphatase and intact osteocalcin (OC) levels were determined by enzyme immunoassay and radioimmunoassay, respectively. Urine was collected at 3 h intervals for 24 h using a tray attached to the bottom of the cage. The levels of N-terminal telopeptide of type I collagen (NTX) were determined by enzyme immunoassay. Pyridinoline and deoxypyridinoline were measured by high performance liquid chromatography. OC and NTX exhibited diurnal variation (Kruskal–Wallis test, P < 0.05), with the highest and lowest levels at 18:00 h (76.7 ± 26.2 ng/ml) and 06:00 h (44.3 ± 10.3 ng/ml), and at 03:00–05:59 h (550.4 ± 82.4 nmol/μmol Cr) and 12:00–14:59 h (297.8 ± 152.5 nmol/μmol Cr), respectively. In the study of age-related changes, blood and urine samples from 66 females (age range, 3–76 months) were examined to determine the bone turnover markers. All markers showed high correlations with age (0.569 < R2 < 0.818). High levels of bone turnover markers were observed in young animals, decreasing with age (Kruskal–Wallis test, P < 0.01). The diurnal variation and age-related changes revealed in the present study will be useful in studies of bone diseases using female Göttingen minipigs.
Experimental animal urine collection: a review
Authors: Kurien Biji T. , Everds Nancy E. , Scofield R. Hal
Published: September 2004

Animal urine collection is a vital part of veterinary practice for ascertaining animal health and in scientific investigations for assessing the results of experimental manipulations. Untainted animal urine collection is very challenging, especially with small rodents, and is an almost impossible task under conditions of microgravity. The fundamental aspects of urine collection are: (1) ease of collection, (2) quality of sample, (3) prevention of contamination, (4) severity of procedures used, (5) levels of pain caused to the animal and (6) refinement of methods to reduce stress, pain or distress. This review addresses the collection of urine for qualitative and quantitative purposes from rodents, rabbits, felines, canines, avian species, equines, porcines, ungulates and certain non-human primates, with animal welfare in mind. Special emphasis has been given to rodents, canines and non-human primates, since they are the animals of choice for research purposes. Free catch (voluntary voiding), methods with mild intervention, surgical methods, modified restraint, cage and special requirement methods have been reviewed here. Efforts need to be taken to provide appropriate animal husbandry and to nurture the animals in as natural an environment as possible since experimental results obtained from these research subjects are, to a great extent, dependent upon their well-being. A continuous refinement in the procedures for collecting urine from experimental animals will be the most efficient way of proceeding in obtaining pure urine specimens for obtaining reliable research data.
Short-term effects of a disturbed light–dark cycle and environmental enrichment on aggression and stress-related parameters in male mice
Authors: Van der Meer E. , Van Loo P. L. P. , Baumans V.
Published: September 2004

In the laboratory setting, environmental factors have a major influence on the well-being of laboratory animals. The present study shows the importance of a semi-natural light–dark cycle. In this experiment one cohort of mice was kept with a continuous lighting for one week. After the first week the artificial light–dark cycle was 12:12 with lights on at 07:00 h. The second cohort of mice was kept with this 12:12 h light–dark cycle from the start. Half of each cohort received environmental enrichment. In order to analyse corticosterone levels, urine samples were collected. To measure agonistic behaviour, the behaviour of the mice was recorded on videotape immediately after cage cleaning. A significant difference in corticosterone levels between cohorts was found during disturbed lighting, but not after lighting conditions were reset to 12:12 h. In the first test week, mice subjected to disturbed lighting also showed a significantly shorter agonistic latency than control mice. This difference had disappeared when in the second test week all mice experienced 12:12 h lighting. No effects of enriched housing were found. This experiment has shown that disturbed lighting for socially-housed male mice caused physiological and behavioural changes indicative of stress, not only leading to much higher levels of corticosterone but also to shorter agonistic latency within the groups.
Non-invasive method for sampling and extraction of mouse DNA for PCR
Authors: Meldgaard M. , Bollen P. J. A. , Finsen B.
Published: September 2004

We adapted a non-invasive, fast, reliable and inexpensive procedure for the sampling and extraction of deoxyribonucleic acid (DNA) for genetic testing of mice. The procedure is based on a simple DNA extraction procedure used in the forensic genetic testing of humans (Rudbeck & Dissing 1998). It involves mouth swabbing of the inner cheek using a cotton stick, followed by alkaline lysis of the harvested buccal epithelial cells. This procedure allows for repeated sampling and genetic testing of the individual mouse, and it is faster, simpler and, in our hands, more reliable than the currently used routine procedures for the sampling and extraction of mouse DNA. Current procedures all involve biopsy of a piece of the tail, ear or toe, followed by lengthy procedures to release and isolate the DNA.
Ximelagatran: An Oral Direct Thrombin Inhibitor
Authors: Dager William E , Vondracek Thomas G , McIntosh Bruce A , Nutescu Edith A
Published: September 2004

OBJECTIVE

To present the chemistry, pharmacology, and pharmacokinetics of ximelagatran, an oral direct thrombin inhibitor (DTI), and to review available comparative clinical trial data evaluating its efficacy and safety relative to other antithrombotic agents in the prevention and treatment of thromboembolism.

DATA SOURCES

A search of the PubMed and Cochrane databases (1995–August 2004), supplemented by a manual search of article bibliographies, conference abstracts, and data on file from the manufacturer, was conducted. Key search terms were ximelagatran, melagatran, H376/95, and direct thrombin inhibitors.

STUDY SELECTION AND DATA EXTRACTION

Pertinent information from available clinical trials, including study design, patient demographics, dosing regimens, anticoagulant comparators, methods for evaluating effectiveness, treatment outcomes, adverse events, and pharmacokinetic and pharmacodynamic evaluations, was extracted.

DATA SYNTHESIS

Ximelagatran is an orally administered DTI under development for use in the treatment of venous thromboembolism (VTE), long-term prevention of a second VTE event, stroke secondary to atrial fibrillation, prevention of VTE after orthopedic procedures, and recurrent ischemic events after acute myocardial infarction.

CONCLUSIONS

Ximelagatran, in twice-daily doses of 24 or 36 mg, is an alternative to low-molecular-weight heparins or warfarin in thromboprophylaxis following orthopedic knee replacement, atrial fibrillation, or initial treatment of VTE. Improved outcomes versus placebo were seen in the long-term prevention of VTE in patients who completed an initial 6 months of treatment. Liver-related effects need further clarification.
Clay minerals in the Meuse-Haute Marne underground laboratory (France): Possible influence of organic matter on clay mineral evolution
Authors: Claret Francis , Sakharov Boris A. , Drits Victor A. , Velde Bruce , Meunier Alain , Griffault Lise , Lanson Bruno
Published: September 2004

A clay-rich Callovo-Oxfordian sedimentary formation was selected in the eastern Paris Basin (MHM site) to host an underground laboratory dedicated to the assessment of nuclear waste-disposal feasibility in deep geological formations. As described initially, this formation shows a mineralogical transition from an illite-smectite (I–S) mixed-layered mineral (MLM), which is essentially smectitic and randomly interstratified (R = 0) in the top part of the series to a more illitic, ordered (R ⩾ 1) I–S in its deeper part.

This description has been challenged by using the multi-specimen method developed by Drits et al. (1997a) and Sakharov et al. (1999). It is shown that all samples contain a physical mixture of an unusually (?) illitic (∼65% I) randomly interstratified I-Exp (illite-expandable MLM) and of a discrete smectite, in addition to discrete illite, kaolinite and chlorite. Structural parameters of the different clay phases vary little throughout the series. According to the proposed model, the mineralogical transition corresponds to the disappearance of smectite with increasing burial depth.

Comparison with clay minerals from formations of similar age (Oxfordian-Toarcian) throughout the Paris Basin shows that the clay mineralogy in the deeper part of the series originates from a smectite-to-illite transition resulting from a low-temperature burial diagenesis. The anomalous lack of evolution of clay minerals in the upper part of the series is thought to be related to specific interactions between organic matter and clay minerals.
Smectite-to-illite alteration in salt-bearing bentonites (The East Slovak Basin)
Authors: Honty M. , Uhlík P. , Šucha V. , Čaplovičová M. , Franců J. , Clauer N. , Biroň A.
Published: September 2004

The effect of a saline environment on illitization in volcanoclastic rocks is examined in deep boreholes in the East Slovak Basin. Based on X-ray diffraction analysis, it is concluded that illite-smectite (I–S) expandability is always less in the salt-bearing bentonites (SBB) than in the salt-free bentonites (SFB) for a given depth interval. These two lithologies can be distinguished easily by water-leachate chemistry. Within the depth interval 2100–2500 m, the expandability in SBB varies within the range 25–10% expandable with R1 and R3 ordering in SBB and 68–35% expandable with R0 ordering in SFB. In two shallow SBB samples the expandability is close to that of SFB, suggesting that salinity alone does not enhance the illitization; but salinity may enhance it when combined with higher burial temperature. Vitrinite reflectance and Tmax of RockEval pyrolysis measured in adjacent shales confirm that the increased illitization in SBB is not due to heating and/or erosion. The model of burial and thermal history calibrated by organic maturity suggests that the same thermal history produces two different expandabilities in the two lithologies (SBB and SFB). Particle thickness measurements and K-Ar data were used to deduce the crystal growth mechanism of illitization in SBB. Whereas surface-controlled growth is typical for SFB, simultaneous nucleation and growth played a more important role in the case of SBB. The effect of a salty environment on the illitization is not yet fully understood and may have severe consequences for the utilization of bentonites as engineering barriers in radioactive waste disposal sites if salt formations used as host rocks are taken into account.
Modeled shale and sandstone burial diagenesis based on the K-Ar systematics of illite-type fundamental particles
Authors: Clauer Norbert , Rousset Davy , Środoń Jan
Published: September 2004

The clay fraction of the sedimentary succession beneath the Mahakam Delta (eastern Kalimantan, Indonesia) consists mainly of mixed-layer illite-smectite, with minor amounts of kaolinite and/or dickite, discrete detrital illite and chlorite. On the near-shore anticline, evolution of this mixed-layer material is characterized by a decrease in expandability with depth. The mechanism of conversion of smectite to illite layers depends on the lithology of the host rocks: it evolves along a solid-state transformation in the shales and a dissolution-precipitation in the sandstones.

Illite fundamental particles from two sandstones buried at ∼4000 m in the Tambora field next to the Handil field on the same near-shore anticline yield a mean K-Ar age of 15.7±1.6 Ma (2σ), which is younger than the stratigraphic age but still slightly biased by minute amounts of discrete detrital illite. Recalculated after modeling, which takes into account the occurrence of the discrete detrital illite, this K-Ar age becomes 14.4±0.7 Ma. The K-Ar values of the fundamental particles from associated buried shales are significantly older, which can be explained by a mixture of (1) a precursor material similar to that presently deposited in the delta of the Mahakam River, and (2) authigenic fundamental particles incorporating Ar with a 40Ar/36Ar ratio above atmospheric value during nucleation and growth on the same detrital precursor.

Application of the modeling to the burial evolution of <0.4 µm particles from both the shales and the sandstones of the basin points to a contribution of detrital micaceous material in both lithologies, (1) in the sandstones as a detrital component dissolving progressively and mixed mechanically with the authigenic fundamental particles, and (2) in the shales as a detrital precursor progressively releasing radiogenic 40Ar by burial alteration, and at the same time acting as a support for the fundamental particles for the growth of authigenic fundamental particles that were found to incorporate Ar characterized by an excess of 40Ar.
Parallel intergrowths in cronstedtite-1T: Implications for structure refinement
Authors: Ďurovič Slavomil , Hybler Jiří , Kogure Toshihiro
Published: September 2004

Cronstedtite is a member of the kaolin-serpentine group. It yields a wealth of more or less disordered polytypes. The crystals of polytype 1T (space group P31m, a = 5.512, c = 7.106 Å) contain, within coherently scattering blocks, variable concentrations of stacking faults so that domains of the basic 3D periodic structure can be shifted by 1/3 (a2 − a1) or 1/3(a1 − a2). These so-called OD parallel intergrowths have been confirmed by high-resolution transmission electron microscopy. The effect manifests itself in the diffraction pattern so that reflections with h-k = 3n — the family reflections — are always sharp, whereas remaining reflections — the characteristic polytype reflections — may be smeared out parallel to c*. The intensities of the latter are thus underestimated during diffractometer measurements. An analysis of such multiple OD intergrowths reveals that the moduli of structure factors for all characteristic (i.e. non-family) polytype reflections are reduced relative to those calculated for the non-intergrown basic structure, by a common factor. This fact usually leads to the appearance of ghost peaks in Fourier maps and to their erroneous interpretation. The structure of the basic model can, however, be refined much better if two scale factors are assigned to the family and non-family reflections, respectively.
Very low-temperature alteration of sideromelane in hyaloclastites and hyalotuffs from Kilauea and Mauna Kea volcanoes: Implications for the mechanism of palagonite formation
Authors: Drief Ahmed , Schiffman Peter
Published: September 2004

Three petrographically distinct styles of altered glasses in two hyaloclastites and one hyalotuff were studied. The texture and chemistry of these samples were investigated using electron probe microanalysis, scanning electron microscopy and transmission electron microscopy in order to understand better the mechanism by which alteration of sideromelane and formation of palagonite occurred in these samples. The results show that clay minerals (primarily smectites) are present in three different microenvironments: (1) coating the surfaces of glass and crystals or vesicle walls; (2) as a relatively heterogeneous, but well crystallized, replacement product (i.e. reddened smectite grain replacement or RSGR) of glass or; (3) as a relatively homogeneous, amorphous to poorly crystalline replacement product (i.e. palagonite). Both the grain size and composition of these smectite-like materials vary considerably.

Crystalline smectites occur in both hyaloclastites and have an intermediate composition between the two end-members nontronite and saponite. This composition could correspond to a mechanical intergrowth and/or an interstratification of two different smectites: one dioctahedral (i.e. nontronite) and one trioctahedral (i.e. saponite or stevensite) or simply to a true di-trioctahedral smectite. The coating smectite appears to have precipitated by a paragenetically-early, dissolution-precipitation mechanism prior to the formation of the RSGR. The high Ti content found in RSGR is attributable to an amorphous Ti-rich material which is intergrown with smectite and which behaves as a sink for immobile elements and those not included in smectite.

Palagonite from both hyaloclastites and hyalotuff is poorly to non-crystalline and more aluminous than the coating smectites. Palagonite from the hyalotuff has an Fe-rich montmorillonite-like composition. The TEM images show a 30–50 nm thick leached layer formed by selective (non-stoichiometric) dissolution that takes place in the fracture domain. The hydration and replacement of glass during the palgonitization process is accompanied by the loss of Fe, Mg and Ca with a concomitant gain of Al. Both palagonites (from hyaloclastites and hyalotuff) show smilar textural and chemical characteristics.
Interactions of two sulfonylurea herbicides with organoclays
Authors: Carrizosa Maria Jose , del Carmen Hermosin Maria , Koskinen William C. , Cornejo Juan
Published: September 2004

The sorption of two sulfonylurea herbicides (SU), metsulfuron methyl and nicosulfuron, on pure clays and organoclays was investigated. Three clays (Arizona smectite, SAz-1, Wyoming smectite, SWy-2, and hectorite, SHCa-1), were treated with amounts of octadecylammonium (ODA) or dioctadecyldimethylammonium (DODMA) cations equal to ∼50 and 100% of the clays’ cation exchange capacity (CEC). Sorption isotherms were fitted to the Freundlich equation. While no measurable sorption was found on the pure clays (Kf = 0), organoclays prepared using both primary and quaternary amines were effective as SU sorbents. The metsulfuron methyl Kf values ranged between 196 and 1498 µmol1−1/n kg−1 L1/n, and Kf values for nicosulfuron, which were lower than those of metsulfuron methyl, ranged from 35 to 198 umol1−1/n kg−1 L1/n. As shown by sorption coefficients, Kd and KOC, SWy-2 treated with DODMA at ∼100% of the CEC was the most effective sorbent for metsulfuron, Kd = 684 L kg−1 and KOC = 2138 L kg−1. For nicosulfuron the most effective sorbent was SAz-1 with ODA at ∼ 50% of the CEC (Kd = 147 L kg−1 and KOC = 1233 L kg−1). In contrast to other weak-acid herbicides, such as phenoxy and picolinic acids, no clear relationships were found between sorption and layer charge, organic carbon content, and basal spacing of the organoclays for both sulfonylurea herbicides. Sorption of both herbicides on organoclays was assumed to involve hydrophobic and polar interactions for which the availability of interlayer room between organocations was a very important factor.
pH-Dependent Photophysical Behavior of Rhenium Complexes Containing Hydroxypyridine Ligands
Authors: Bare William D. , Mack Nathan H. , Demas J. N. , DeGraff B. A.
Published: September 2004

Data related to the pH-dependent photophysics of a class of rhenium complexes containing the hydroxypyridine ligand are presented. Data include ground-state pKa values, emission energies, and lifetimes. The complexes all have ground-state pKa values near 7.0 and exhibit a dramatic change in emission intensity near this pH. The lifetimes of these complexes, however, are constant over this pH range. A model is presented to account for the observed photophysical behavior. The pH-dependent emission properties of these species make them good candidates for luminescence-based pH probes, especially in the environmental and biomedical fields.
Effects of Nonlinearities and Uncorrelated or Correlated Errors in Realistic Simulated Data on the Prediction Abilities of Augmented Classical Least Squares and Partial Least Squares
Authors: Melgaard David K. , Haaland David M.
Published: September 2004

Comparisons of prediction models from the new augmented classical least squares (ACLS) and partial least squares (PLS) multivariate spectral analysis methods were conducted using simulated data containing deviations from the idealized model. The simulated data were based on pure spectral components derived from real near-infrared spectra of multicomponent dilute aqueous solutions. Simulated uncorrelated concentration errors, uncorrelated and correlated spectral noise, and nonlinear spectral responses were included to evaluate the methods on situations representative of experimental data. The statistical significance of differences in prediction ability was evaluated using the Wilcoxon signed rank test. The prediction differences were found to be dependent on the type of noise added, the numbers of calibration samples, and the component being predicted. For analyses applied to simulated spectra with noise-free nonlinear response, PLS was shown to be statistically superior to ACLS for most of the cases. With added uncorrelated spectral noise, both methods performed comparably. Using 50 calibration samples with simulated correlated spectral noise, PLS showed an advantage in 3 out of 9 cases, but the advantage dropped to 1 out of 9 cases with 25 calibration samples. For cases with different noise distributions between calibration and validation, ACLS predictions were statistically better than PLS for two of the four components. Also, when experimentally derived correlated spectral error was added, ACLS gave better predictions that were statistically significant in 15 out of 24 cases simulated. On data sets with nonuniform noise, neither method was statistically better, although ACLS usually had smaller standard errors of prediction (SEPs). The varying results emphasize the need to use realistic simulations when making comparisons between various multivariate calibration methods. Even when the differences between the standard error of predictions were statistically significant, in most cases the differences in SEP were small. This study demonstrated that unlike CLS, ACLS is competitive with PLS in modeling nonlinearities in spectra without knowledge of all the component concentrations. This competitiveness is important when maintaining and transferring models for system drift, spectrometer differences, and unmodeled components, since ACLS models can be rapidly updated during prediction when used in conjunction with the prediction augmented classical least squares (PACLS) method, while PLS requires full recalibration.
Application of Generalized Two-Dimensional Infrared Correlation Spectroscopy to the Study of a Hydrogen-Bonded Blend
Authors: Huang He , Malkov Serghei , Coleman Michael M. , Painter Paul C.
Published: September 2004

In the preceding studies in this series, generalized two-dimensional (2D) infrared correlation spectroscopy has been applied to the study of polymer blends with relatively weak intermolecular interactions. In this paper, a miscible system with strong intermolecular interactions, hydrogen-bonded blends of poly(4-vinyl phenol) (PVPh) and poly(methyl methacrylate) (PMMA), is considered. It has been found that band positions in 2D plots are dependent on the data sets used, due to large peak shifts and/or bandwidth changes. This observation complements our preceding studies, in which it was found that new features correspond to maxima, minima, or points of inflection in the difference spectra used to generate the 2D plots and are not normal modes of vibration of specific functional groups. Great care needs to be taken in order not to interpret artifacts of the procedure in terms of new spectroscopic features.
Vibrational Spectroscopic Study on the Origin of Stress Oscillation during Step-Wise Stretching in Poly(Ethylene Terephthalate)
Authors: Kandilioti Georgia , Govaris Giannis K. , Gregoriou Vasilis G.
Published: September 2004

The origin of the phenomenon of stress oscillation during step-wise stretching at room temperature for amorphous poly(ethylene terephthalate) (PET) was investigated using vibrational spectroscopy. For the first time, transmission Fourier transform infrared (FT-IR), attenuated total reflection (ATR) FT-IR, and micro-Raman spectroscopies were used in order to investigate the correlation of the orientation of the molecular chains, their conformational transformations, and the appearance of stress-induced crystallization to the phenomenon of stress oscillation during the step-wise stretching procedure. The phenomenon of stress oscillation occurs when amorphous PET is exposed to mechanical stress during which the extension rate is increased in a step-wise manner. This phenomenon leads to the formation of a pattern of opaque and transparent stripes (“striated” or oscillating region), clearly distinguished from the unstretched (“bulk”) and the “necking” regions. Both infrared and Raman spectroscopic investigations revealed that the main conformational transformations and a significant increase of the crystallinity occur simultaneously in the “striated” region. Polarized infrared experiments showed the presence of increased molecular orientation, which is more profound for the “intense striated” region. Finally, micro-Raman spectroscopy allowed the study of opaque and transparent stripes individually and showed that the opaque stripes are more crystalline. Thus, our findings provide conclusive experimental support for the theory, which directly correlates the appearance of the stress-oscillation phenomenon with the induction of crystallinity and heat release and is based on Barenblatt's model. Our study also provides new conformational assignments for the infrared bands in PET for the high-frequency region from 3200 to 3800 cm−1. Specifically, the bands at 3336 cm−1 and at 3298 cm−1 have been attributed to the trans and gauche conformations, respectively.
Determination of the Maximum Temperature at the Center of an Optically Thick Laser-Induced Plasma Using Self-Reversed Spectral Lines
Authors: Gornushkin I. B. , Omenetto N. , Smith B. W. , Winefordner J. D.
Published: September 2004

A method of temperature measurement based on the model developed by Bartels of an optically thick inhomogeneous plasma was applied to a laser plasma induced on a target containing barium. The method involves the intensity ratio measurement of two self-reversed Ba(II) lines. The temperature thus determined corresponds to the maximum temperature in the plasma center. The plasma temperature was measured for delay times between 0.5 μs and 10 μs in two spectrometer operating modes: the scanning mode and the dual-wavelength mode, the latter resulting in better precision. A detailed analysis of experimental errors was performed. The error strongly depended on the wavelength separation of the lines used. The most accurate results were obtained for the largest line separation. Using one line in the UV and the other in the visible region, the relative error was 2–6% for temperatures between 8000 K and 20 000 K. The distribution of the plasma temperature along the plasma height was measured in the same delay time range. The temperature was found to be uniform along the plasma vertical axis, thus confirming the plasma cylindrical symmetry.
Electron Density and Gas Temperature from Line Broadening in an Argon Surface-Wave-Sustained Discharge at Atmospheric Pressure
Authors: Christova M. , Castaños-Martinez E. , Calzada M. D. , Kabouzi Y. , Luque J. M. , Moisan M.
Published: September 2004

We have used the collisional broadening of neutral argon lines to determine the electron density and gas temperature of a microwave discharge at atmospheric pressure. The gas temperature can be obtained from the Van der Waals broadening, provided that the Stark broadening is negligible. This can be achieved by using lines from low-lying levels (close to the ground state). On the other hand, lines corresponding to transitions from high-lying levels, which are more sensitive to Stark (quadratic) broadening, can be utilized to determine electron density. The electron density values obtained from the quadratic Stark broadening of argon atoms are in reasonable agreement with those derived from the linear Stark broadening of the Hβ line. The proposed method ensures perturbation-free access to plasma parameters, which is not the case when adding hydrogen to the discharge, even in a small amount, to observe the Balmer series lines.
Extension of Fourier Transform Vibrational Circular Dichroism into the Near-Infrared Region: Continuous Spectral Coverage from 800 to 10 000 cm−1
Authors: Cao Xiaolin , Shah Rekha D. , Dukor Rina K. , Guo Changning , Freedman Teresa B. , Nafie Laurence A.
Published: September 2004

We report the first vibrational circular dichroism (VCD) spectra with continuous coverage from 800 cm−1 in the mid-infrared (MIR) region to 10 000 cm−1 in the near-infrared (NIR) region. This coverage is illustrated with MIR and NIR absorbance and VCD spectra of 2,2-dimethyl-dioxolane-4-methanol (DDM), α-pinene, and camphor that serve as calibration samples over this entire region. Commercially available, dual-source Fourier transform (FT) MIR and NIR VCD spectrometers were equipped with appropriate light sources, optics, and detectors, and were modified for dual-polarization-modulation (DPM) operation. The combination of liquid-nitrogen- and thermoelectric-cooled HgCdTe (MCT) detectors, as well as InGaAs and Germanium (Ge) detectors operating at room temperature, permitted collection of the desired absorbance and VCD spectra across the range of vibrational fundamental, combination band, and overtone frequencies. The spectra of DDM and α-pinene were measured as neat liquids and recorded for both enantiomers in the various spectral regions. Spectra for camphor were all measured in CCl4 solution at a concentration of 0.6 M, except for the carbonyl-stretching region, where a more dilute concentration was used. The typical anisotropy ratios ( g) of the three molecules were estimated with respect to their strongest VCD bands in each spectral region. It was found that for all three molecules in the spectral regions above 2000 cm−1, anisotropy ratios are approximately the same order (10−5) of magnitude. However, in the MIR region, the typical anisotropy ratios are significantly different for the three molecules. This study demonstrates that with modern FT-VCD spectrometers modified for DPM operation, VCD spectra can be measured continuously across a wide spectral range from the MIR to nearly the visible region with an unsurpassed combination of signal-to-noise ratio and spectral resolution.
Micro-Raman Spectroscopy for Optical Pathology of Oral Squamous Cell Carcinoma
Authors: Krishna C. Murali , Sockalingum G. D. , Kurien Jacob , Rao Lakshmi , Venteo L. , Pluot M. , Manfait M. , Kartha V. B.
Published: September 2004

Micro-Raman spectra of formalin-fixed oral squamous normal and carcinoma tissues, stored at room temperature for 2 months, have been recorded. Spectra were recorded both in the epithelial and subepithelial regions of the tissues. No noticeable spectral contamination due to formalin was observed. Very significant differences between spectra of normal epithelial and malignant epithelial samples were found. No such differences in spectra of subepithelial malignant and subepithelial normal samples could be observed. This study shows that spectra from the epithelial region changes drastically because of malignancy-induced biochemical changes in this region. Major differences between normal and malignant spectra seem to arise from the protein composition, conformational/structural changes, and possible increase in protein content in malignant epithelia. The differences between normal epithelial and subepithelial spectra, as expected, arise mainly from the collagen in subepithelial tissue. Principal component analysis of the combined sets of spectra—epithelial and subepithelial, normal and malignant— showed that very good discrimination can be achieved by Raman microspectroscopy. This study thus validates the suitability of formalin-fixed tissues for optical pathology in oral malignancy.
Time-Resolved Fluorescence Microspectroscopy for Characterizing Crude Oils in Bulk and Hydrocarbon-Bearing Fluid Inclusions
Authors: Ryder Alan G. , Przyjalgowski Milosz A. , Feely Martin , Szczupak Boguslaw , Glynn Thomas J.
Published: September 2004

Time-resolved fluorescence data was collected from a series of 23 bulk crude petroleum oils and six microscopic hydrocarbon-bearing fluid inclusions (HCFI). The data was collected using a diode laser fluorescence lifetime microscope (DLFLM) over the 460–700 nm spectral range using a 405 nm excitation source. The correlation between intensity averaged lifetimes (τ̄) and chemical and physical parameters was examined with a view to developing a quantitative model for predicting the gross chemical composition of hydrocarbon liquids trapped in HCFI. It was found that τ̄ is nonlinearly correlated with the measured polar and corrected alkane concentrations and that oils can be classified on this basis. However, these correlations all show a large degree of scatter, preventing accurate quantitative prediction of gross chemical composition of the oils. Other parameters such as API gravity and asphaltene, aromatic, and sulfur concentrations do not correlate well with τ̄ measurements. Individual HCFI were analyzed using the DLFLM, and time-resolved fluorescence measurements were compared with τ̄ data from the bulk oils. This enabled the fluid within the inclusions to be classified as either low alkane/high polar or high alkane/low polar. Within the high alkane/low polar group, it was possible to clearly discriminate HCFI from different locales and to see differences in the trapped hydrocarbon fluids from a single geological source. This methodology offers an alternative method for classifying the hydrocarbon content of HCFI and observing small variations in the trapped fluid composition that is less sensitive to fluctuations in the measurement method than fluorescence intensity based methods.
TheTlxGene Regulates the Timing of Neurogenesis in the Cortex
Authors: Roy Kristine , Kuznicki Kathleen , Wu Qiang , Sun Zhuoxin , Bock Dagmar , Schutz Gunther , Vranich Nancy , Monaghan A. Paula
Published: September 2004

Thetailless(tlx) gene is a forebrain-restricted transcription factor.Tlxmutant animals exhibit a reduction in the size of the cerebral hemispheres and associated structures (Monaghan et al., 1997). Superficial cortical layers are specifically reduced, whereas deep layers are relatively unaltered (Land and Monaghan, 2003). To determine whether the adult laminar phenotype has a developmental etiology and whether it is associated with a change in proliferation/differentiation decisions, we examined the cell cycle and neurogenesis in the embryonic cortex. We found that there is a temporal and regional requirement for the Tlx protein in progenitor cells (PCs). Neurons prematurely differentiate at all rostrocaudal levels up to mid-neurogenesis in mutant animals. Heterozygote animals have an intermediate phenotype indicating there is a threshold requirement for Tlx in early cortical neurogenesis. Our studies indicate that PCs in the ventricular zone are sensitive to loss of Tlx in caudal regions only; however, PCs in the subventricular zone are altered at all rostrocaudal levels intlx-deficient animals. Furthermore, we found that the cell cycle is shorter from embryonic day 9.5 intlx–/–embryos. At mid-neurogenesis, the PC population becomes depleted, and late PCs have a longer cell cycle in tlx-deficient animals. Consequently, later generated structures, such as upper cortical layers, the dentate gyrus, and the olfactory bulbs, are severely reduced. These studies indicate thattlxis an essential intrinsic regulator in the decision to proliferate or differentiate in the developing forebrain.