bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxcarbazepine Use in Essential Tremor
Authors: Raj Vidya , Landess Jacqueline S , Martin Peter R
Published: September 2006

Objective:

To report the novel finding of a significant improvement in essential tremor symptoms with oxcarbazepine in a patient with a suboptimal response to propranolol.

Case Summary:

A 40-year-old woman with a history of substance abuse complicated by essential tremor and neuropathic pain was admitted to our addictions unit with altered mental state due to escalating use of alprazolam. Alprazolam had been prescribed several months prior to admission for treatment of anxiety. The doses had risen to 5–10 mg/day during that period. Apparently, her essential tremor had responded inadequately to propranolol, but had responded well to alprazolam. She was started on a sedative/hypnotic withdrawal protocol, but did not require treatment with phenobarbital. She subsequently rated her tremor as “moderately severe.” On discontinuation of the withdrawal protocol, oxcarbazepine 450 mg twice daily was initiated to treat her neuropathic pain, and the tremor improved, with a clinically significant reduction in tremor and a decreased pain score.

Discussion:

Essential tremor is a common neurologic disorder with uncertain pathophysiology. Practice guidelines advocate the use of propranolol or primidone as first-line agents to treat essential tremor. Unfortunately, primidone has abuse potential and propranolol has variable pharmacokinetics; these characteristics limit their effectiveness in treating tremor. Our patient experienced a significant and sustained improvement in her tremor following the initiation of oxcarbazepine. To our knowledge, as of September 2, 2006, this is the first report of the use of oxcarbazepine in essential tremor. While the exact therapeutic action remains unclear, oxcarbazepine offers significant advantages compared with current first-line agents, including its good tolerability profile, the extended half-life of its metabolite, and lack of abuse potential.

Conclusions:

We report a case of essential tremor responding to oxcarbazepine. This drug offers several potential advantages over current first-line agents. Further research is warranted to test the robustness of this preliminary finding.
A Comparative Study of Consumer Participation in Mental Health Pharmacy Education
Authors: Bell J Simon , Johns Rachelle , Rose Grenville , Chen Timothy F
Published: September 2006

Background:

People with mental illness have been recognized as key stakeholders in the development of mental health education. However, few studies have evaluated the impact of people with mental illness as participants in education programs for students studying to become health professionals.

Objective:

To assess the impact of education provided by mental health consumer–educators on the attitudes of pharmacy students toward people with mental illness.

Methods:

The study used a 2 group, nonrandomized, clustered, comparative design, with 4 tutorial classes allocated to receive standard pharmacist-led instruction (comparison group), and 5 tutorial classes to receive standard pharmacist-led instruction plus additional input from mental health consumer–educators (intervention group). All pharmacy students (N = 229) enrolled in the third year of a 4 year pharmacy degree program were invited to participate. Consumer–educators receiving ongoing treatment for illnesses including schizophrenia, bipolar disorder, and major depression participated in small-group work, case-study discussions, and role plays with pharmacy students in the intervention group. Pharmacy students' attitudes were assessed using a 39 item survey instrument derived from previously published instruments evaluating social distance, attribution, provision of pharmaceutical services, and stigmatization of people with schizophrenia and severe depression.

Results:

Paired baseline and follow-up responses were obtained from 117 students in the intervention group and 94 students in the comparison group. Students who received the consumer intervention had decreased social distance scores (F(1209) = 5.30; p = 0.02). Students in the intervention group more strongly disagreed with 26 of 27 nonsocial distance statements that demonstrated a negative attitude toward people with mental illness (F(1209) = 13.58; p < 0.001) and more strongly agreed with all 4 nonsocial distance statements that demonstrated a positive attitude (F(1209) = 7.56; p = 0.014).

Conclusions:

Consumer participation in mental health education for pharmacy students improves students' attitudes toward people with mental illness.
Clinical Outcomes Associated with Concomitant Use of Atazanavir and Proton Pump Inhibitors
Authors: Sahloff Eric G , Duggan Joan M
Published: September 2006

Background:

Pharmacokinetic studies have shown that the concomitant use of atazanavir and proton pump inhibitors (PPIs) decreases atazanavir plasma concentrations. Data describing clinical outcomes associated with this drug interaction are limited.

Objective:

To describe the clinical outcomes, in terms of viral load (VL) suppression, associated with the concurrent use of ritonavir-boosted or unboosted atazanavir and PPIs.

Methods:

A retrospective chart review of 301 HIV-positive adults attending an Ohio infectious diseases clinic was performed to identify patients prescribed atazanavir, with or without ritonavir, and a PPI. The primary outcome was achievement/maintenance of VL less than 400 copies/mL for 2 or more months during concomitant atazanavir and PPI therapies. Data collected included VL and CD4+ cell count at initiation of coadministered atazanavir and PPIs, genotype/phenotype, prior protease inhibitor experience, length of concurrent atazanavir/PPI therapy, and adherence.

Results:

Twelve patients met inclusion criteria. PPIs and dosing regimens varied among subjects. Five of the subjects had a VL less than 400 copies/mL at initiation of atazanavir, with or without ritonavir, which was maintained during concurrent atazanavir and PPI therapy. Four additional subjects initiated protease inhibitor treatment with a VL greater than 400 copies/mL and achieved an undetectable VL while on concurrent PPI therapy. Duration of concurrent therapy ranged from 4 to 23 months in these 9 subjects. Of the 3 patients not maintaining a VL less than 400 copies/mL, 1 achieved that level at 4 months, and all 3 of these subjects showed atazanavir susceptibility during therapy per genotype resistance testing. Subsequently, decreased atazanavir susceptibility was reported in 1 of the 3 patients after 18 months of therapy. Patients not achieving an undetectable VL had known adherence issues.

Conclusions:

In this case series, 9 of 12 subjects achieved successful virologic outcomes while receiving concurrent atazanavir and PPIs in a real-world environment. In our experience, the interaction between atazanavir and once-daily PPIs is not clinically significant for adherent patients. Concurrent use of these medications could be considered in patients with limited treatment options.
Supplementary Prescribing: Early Experiences of Pharmacists in Great Britain
Authors: George Johnson , McCaig Dorothy J , Bond Christine M , Cunningham IT Scott , Diack H Lesley , Watson Anne M , Stewart Derek C
Published: September 2006

Background:

Pharmacists in Great Britain can undertake supplementary prescribing (SP) after training at a higher education institution and completing a “period of learning in practice” in accordance with the Royal Pharmaceutical Society of Great Britain (RPSGB) curriculum.

Objective:

To explore SP pharmacists' early experiences of prescribing and their perceptions of the prescribing course.

Methods:

A questionnaire was mailed to all RPSGB prescribers (N = 518, on June 1, 2005; 30 used in pilot questionnaire). Predictors of pharmacists starting to practice SP were identified in univariate analysis, and significant variables were further tested in multivariate analysis.

Results:

The respondents (n = 401; 82.2%) were mainly female (270; 67.3%), had more than 20 years' experience as a pharmacist (123; 30.7%), worked in hospital settings (160; 39.9%), and focused on cardiovascular conditions (143; 35.7%) during their period of learning in practice. The median course satisfaction score, on a scale of 3 to 15 (lowest to highest), was 10. Practicing SP was self-reported by 195 (48.6%) respondents, 154 (79%) of whom had written a prescription. Ninety (58.4%) of the first prescriptions were written in primary care settings. Better patient management was regarded as the major benefit by 139 (71.3%) of those engaged in SP, while funding issues were identified by 71 (36.4%) as major barriers in implementing the practice. Lack of organizational recognition of SP was the main reason given (37; 18%) for those not commencing the practice. Independent predictors of those practicing SP included a longer time since registering as prescriber (p < 0.001); confidence of pharmacists in their prescribing abilities (p < 0.001); practicing in a setting other than community pharmacy (p = 0.001); and training in cardiovascular conditions or multiple conditions during the period of learning in practice (p = 0.005).

Conclusions:

Pharmacists have made progress in implementing SP, which is perceived by pharmacist prescribers as beneficial for both patients and themselves. Pharmacists need more support in terms of infrastructure and integration into the healthcare team to overcome some of the barriers to implementing SP.
Hydrothermal Reactivity of Saponite
Authors: Whitney Gene
Published: September 2006

Saponite crystallizes from amorphous gel having an ideal saponite composition within 7 days at all experimental temperatures between 300° and 550°C at 1 kbar pressure. Reactions subsequent to this initial crystallization vary in type and degree, depending on the temperature of reaction and the type of interlayer cation. Above 450°C, the intitially crystallized K-saponite dissolves, and talc and phlogopite nucleate and grow as discrete phases. At 450°C the initial K-saponite reacts to form talc and phlogopite layers, but the reaction proceeds via intracrystalline layer transformations rather than via dissolution and precipitation, producing a mixture of fully ordered, interstratified talc/saponite and fully ordered saponite/phlogopite. The K-saponite shows subtle signs of reaction at 400°C after 200 days: this temperature is at least 150°C lower than experimental reaction temperatures previously reported for saponites. No reactions beyond the initial crystallization of saponite were observed below 400°C. K-saponite reacts more rapidly than either Na-saponite or Ca-saponite above 400°C, and the Na-saponite and Ca-saponite produce no mica layers during their transformation to mixed-layer clays. Interstratified talc/saponite formed in the Na-saponite system, and the Ca-saponite system produced both talc/saponite and chlorite/saponite.
Physicochemical Properties of Montmorillonite Interlayered with Cationic Oxyaluminum Pillars
Authors: Occelli M. L. , Tindwa R. M.
Published: September 2006

By ion exchanging expandable clay minerals with large, cationic oxyaluminum polymers, “pillars” were introduced that permanently prop open the clay layers. On the basis of thermal, infrared spectroscopic, adsorption, and X-ray powder diffraction (XRD) analysis, the interlayering of commercial sodium bentonite with aluminum chlorohydroxide, [Al13O4(OH)24(H2O)12]+7, polymers appears to have produced an expanded clay with a surface area of 200–300 m2/g. The pillared product contained both Brönsted and Lewis acid sites. XRD and differential scanning calorimetry measurements indicated that the micropore structure of this interlayered clay is stable to 540°C. Between 540° and 760°C, the pillared clay collapsed with a corresponding decrease in surface area (to 55 m2/g) and catalytic cracking activity for a Kuwait gas oil having a 260°-426°C boiling range.
Adsorption of Quinoline from Aqueous Solutions by Some Clays and Oxides
Authors: Helmy A. K. , De Bussetti S. G. , Ferreiro E. A.
Published: September 2006

The adsorption isotherms of quinoline from aqueous solutions by some clays and oxides varied from the S type for silica to a form somewhat similar to the Langmuir type for montmorillonite and silica-alumina. The adsorption reaction reached equilibrium in about 2 hr and was irreversible. X-ray powder diffraction studies showed that a single layer of molecules is adsorbed on montmorillonite and that the molecules lie either flat or in an upright position depending on surface coverage. The adsorption showed high sensitivity towards pH, attaining a maximum at pH 6. The decrease below pH 6 was due to competition with protons as well as to problems inherent in surface packing of positively charged quinoline molecules. The decrease above pH 6 is probably due to more exchangeable metallic cations on the surface leading to a favored sorption of water over organic molecules.
Mineralogical Transformations During Weathering of Lignite Overburden in East Texas
Authors: Senkayi A. L. , Dixon J. B. , Hossner L. R. , Viani B. E.
Published: September 2006

Mineralogical weathering sequences in sediments overlying lignite beds were investigated in a core (27 m deep) from Calvert, Robertson County, northeast Texas. Weathering trends were evaluated based on the properties and relative distributions of both the expandable and non-expandable minerals. The sulfide minerals in these sediments are the most susceptible to weathering and were only observed in the unaltered (reduced) zone below 7 m. Oxidation of the sulfides has resulted in the formation of jarosite and gypsum in the upper 7 m of the core (oxidized zone). The oxidized zone is further characterized by reddish brown colors (high chroma), a greater quantity of dithionite-extractable iron, and absence of chlorite. Although the major clay minerals in these sediments (smectite, kaolinite, mica) are largely detrital, weathering has resulted in an increase in the content of kaolinite and a decrease in the content of mica towards the surface. The mica appears to have altered to a high-charge smectite characterized by basal spacings of 32 Â after intercalation with octadecylammonium cations. The high-charge smectite is most abundant in the soil horizons at the top of the core and gradually decreases with depth. A low-charge smectite is the most abundant species in the un weathered parent sediments and increases with depth. Key Words—Lignite, Oxidation, Reclamation, Smectite, Soil, Weathering.
Infrared Studies of Ni-Bearing Clay Minerals of the Kerolite-Pimelite Series
Authors: Gerard P. , Herbillon A. J.
Published: September 2006

Two kerolite and one garnierite samples were subjected to progressive heat treatments prior to their examination by infrared spectroscopy (IR) in the 1200-600-cm−1 and 3800-3000-cm−1 regions. The heat treatment of the garnierite (a mixture of nepouite and pimelite) selectively dehydroxylated the nepouite thus allowing an examination to be made of the OH-vibration bands due to the pimelite. Both the relative intensities of the 710-670-cm−1 doublet and of the different OH-stretching bands indicated the Ni content of this pimelite to be about 70%. The heat treatments did not modify the 1200-600-cm−1 region of the spectra of kerolites but caused a noticeable sharpening in the OH-stretching region. The relative intensities of the structural OH-stretching bands of dehydrated kerolites showed that they differ from Ni-talcs of similar composition in the distribution of Ni and Mg in the octahedral sites. These cations are randomly distributed in Ni-talc but are mainly segregated into Mg and Ni domains in kerolite. Changes in sharpness, intensity, and position of the structural OH-stretching bands of the kerolites as temperature increases and dehydration progresses are similar to those undergone by Mg- or Li-saturated trioctahedral smectites. Also thermal analysis curves of these minerals show similarities with those of Mg- and Ni-saturated smectites, and suggest that in kerolites too, the hydration water is associated with interlayer (though non-exchangeable) Ni and/or Mg cations.
Clay Minerals of Lake Abert, an Alkaline, Saline Lake
Authors: Jones Blair F. , Weir Alan H.
Published: September 2006

Mineralogical and chemical analyses of fine clay fractions from in and around Lake Abert, Lake County, Oregon, show that the pyroclastic rocks supplying detritus to the lake weather to a suite of layer silicate clay minerals varying from high-charge dioctahedral montmorillonite to montmorillonite/intergrade smectite-chlorite interstratifications. In the lake these clays extract K, Mg, and Si to form authigenic interstratified illite and a trioctahedral, Mg-rich mineral resembling stevensite in composition. Both the neoformed interstratifications contribute little unambiguously to X-ray powder diffraction patterns, which are dominated by the reflections of detrital clays. From limited data it appears that the illite occurs below 0.8 m depth in sediments of a possibly somewhat fresher (brackish) lake and the trioctahedral interstratification between 0.4 and 0.2 m depth in sediments of a lake of about the same size and salinity (about 30–90 g/kg) as that of the present lake.
Origin of Berthierine in Ironstones
Authors: Bhattacharyya Deba P.
Published: September 2006

To test the hypothesis that berthierine in oolitic ironstones formed by diagenetic transformation of detrital kaolinite, laboratory experiments simulating the early diagenetic conditions were conducted. Representative sets of the initial sediment were prepared in distilled water and artificial seawater suspensions by mixing 4–13 g/liter kaolinite with Fe(OH)3 precipitated from 0.1-0.3 M FeCl3 solutions. Na2S2O4 was added to the suspensions as a reducing agent, and inert N2 atmospheres were used to maintain the required Eh between +100 and -400 mV. The pH of the suspensions was controlled between 8 and 5 with dilute HCl. Within 300 days, the iron content of the bulk kaolinite in the seawater suspensions progressively increased from 0.18 to 2.44% at pH = 7 and Eh between -250 and -350 mV. Energy dispersive X-ray analyses of individual clay platelets in the final products showed progressive, temporal increase in Fe, and concomitant decrease in Al and Si. X-ray powder diffractometry revealed small d(001)-d(002) shifts, marked intensity reversals o. (001) an. (002) reflections, and the development of additional characteristic berthierine reflections with time. These data suggest progressive transformation of kaolinite to berthierine. Microprobe analyses of natural berthierine in oolitic ironstones also showed parallel patterns, which substantiate such progressive transformation from the margin toward the core of the ooids. The transformation did not take place in distilled water. The addition of Mg2+ to the distilled water suspensions, however, promoted the transformation.
Calculation of Electrostatic Interlayer Bonding Energy and Lattice Energy of Polar Phyllosilicates: Kaolinite and Chlorite
Authors: Hartman P.
Published: September 2006

The electrostatic lattice energy of polar phyllosilicates can be calculated when a correction term Ecorr equal to -2πμ2/V is taken into account, where μ is the dipole moment of a slice d(001) and V is the molecular volume. The interlayer bonding energy can be obtained by Giese's method, if the energy of separation of the layers over a distance A is plotted againts 1/[d(001) + Δ]. Thus, for a polar chlorite the interlayer bonding energy is 69.8 kJ/unit cell. Using the Madelung method, the interlayer bonding energy of slices of kaolinite having a thickness of d(001) is 84 kJ/mole. Similarly the interlayer bonding energy of slices having a thickness d(020) is 2520 kJ/mole. To avoid the instability of the outer slices of the crystal caused by the cooperating dipole moments of all slices, the hypothesis was made that the atoms have in reality reduced charges and that the charge reduction is such that the dipole moment becomes zero. The adopted charges lower the interlayer bonding energy to as little as 14 kJ/mole. The interlayer interaction of slices of fluorkaolinite with thickness d(001) is repulsive. Crystals of a polar chlorite must be bounded either by incomplete hydroxide layers or by layers onto which charge-compensating anions are adsorbed. Polarity makes cleavage in chlorite more difficult.
Mössbauer Effect Studies of Iron in Kaolin. I. Structural Iron
Authors: Fysh S. A. , Cashion J. D. , Clark P. E.
Published: September 2006

57Fe Mössbauer spectra of a cleaned Weipa, Australia, kaolin showed that a considerable fraction of the structural iron exhibits paramagnetic relaxation between 4°K and 300°K, the first time that this has been observed for ferric ions in a mineral. The sample also contained a very fine particle ferric oxide/oxyhydroxide phase, probably of secondary origin.
Mössbauer Effect Studies of Iron in Kaolin. II. Surface Iron
Authors: Fysh S. A. , Cashion J. D. , Clark P. E.
Published: September 2006

57Fe Mössbauer spectra have been used to interpret the effects of different cleaning processes on the iron mineralogy of a Weipa, Australia, kaolin. A magnetically separated fraction contained 28% of its iron as hematite likely of secondary origin. An initial centrifugal size separation was shown to give an improved final product, and oxalic acid was found to be more efficient at removing Fe from the kaolinite surface than dithionite bleach. The Mössbauer spectra clearly show that beneficiation steps which give a substantial increase in kaolin brightness result in only minor changes in the clay iron mineralogy. Similar results were also obtained for two commercially available kaolins.
Sorption of Trace Constituents from Aqueous Solutions Onto Secondary Minerals. I. Uranium
Authors: Ames L. L. , McGarrah J. E. , Walker B. A.
Published: September 2006

Well-characterized American Petroleum Institute clay standards, source clays from The Clay Minerals Society, and other secondary minerals were used to determine the effects of U concentration, temperature, and solution composition on U-sorption properties. Uranium concentrations ranged from about 1.00 × 10−4 M to 4.00 × 10−7 M, temperatures from 5° to 65°C and solution compositions containing 0.01 M NaCl and 0.01 M NaHCO3. Silica gel efficiently sorbed uranyl carbonate anion complexes. The higher cation-exchange capacity materials most readily sorbed uranyl ions from the 0.01 M NaCl solution. Temperature increases tended to affect uranyl ion sorption adversely except when the U was present as carbonate complexes. Noncrystalline ferric oxyhydroxides sorbed uranyl ions much more efficiently than any of the secondary crystalline minerals studied. A method for accurately extrapolating U-sorption efficiencies between experimental points based on the Freundlich equation is presented.
Further Investigations of a Conversion Series of Dioctahedral Mica/Smectites in the Shinzan Hydrothermal Alteration Area, Northeast Japan
Authors: Inoue Atsuyuki , Utada Minoru
Published: September 2006

A complete conversion series for mica/smectites was found in a hydrothermal alteration envelope around Kuroko-type ore deposits at the Shinzan area, Akita Prefecture, Northeast Japan. The minerals are an alteration product of volcanic glass of Miocene age and are commonly associated with zeolites and silica minerals. Degrees of ordering of interstratification of the minerals change discontinuously from Reichweite g = 0 (100–55% expandable layers) to g = 1 (45–20% expandable layers), and from g = 1 to g = 2 (<20% expandable layers). This pattern of conversion differs from the behavior of mica/smectites during burial diagenesis which undergo a continuous change in ordering type, and from the behavior of rectorite which displays a constant expandability and ordering (45–55%) over a wide range of conditions. Differences between these minerals were also found in the relationships between expandability and total layer charge, and between expandability and number of non-exchangeable interlayer cations. In mica/smectites from the Shinzan area, chemical changes in the interlayers and tetrahedral and octahedral sites are consistent with a reaction in which K-enrichment and K-fixation in the interlayers are controlled by an increase in negative layer charge. This conversion occurred in response to a steep geothermal gradient and migrating hydrothermal solutions.
Spherical Kaolinite: Synthesis and Mineralogical Properties
Authors: Tomura Shinji , Shibasaki Yasuo , Mizuta Hiroyuki , Kitamura Masao
Published: September 2006

Spherical kaolinite has been synthesized for the first time from noncrystalline aluminosilicate material in hydrothermal experiments conducted between 150° and 250°C and under autogenous vapor pressure. Spherules, whose mean diameters depended on growth conditions (0.1–0.6 μm), were formed surrounding the noncrystalline aluminosilicate in all products of 150° and 200°C runs and coexisted with platy or lath-shaped kaolinite in the products of 250°C runs. The estimated percentages of spherules in the products increased from about 1% in the 150°C-15 days product to about 74% in 200°C-8 days product, and decreased from about 21% in 250°C-2 days product to 0% in 250°C-8 days product. Lattice images by high-resolution electron microscope indicated that the spherules consisted of nearly concentric stackings of layers with a unit spacing of 7Å, which were sectored by radiating boundaries. The mean chemical composition of the spherules (Al2O3/SiO2 = 0.58) analyzed by the analytical electron microscope is similar to that of kaolinite (Al2O3/SiO2 = 0.5). Even in the case of the product abundant in spherule (200°C-8 days), X-ray powder diffraction patterns of the wetted products, e.g., of the 200°C-8 day run, showed the 7.14-Å (001) reflection of kaolinite. The 020 reflection was broad, indicating the existence of abundant (001) layer displacements. The b axis (8.94 Å) were within the kaolinite range (8.93–8.94 Å). No infrared absorption peaks were observed at 3550 cm−1 which would correspond to halloysite. The differential thermal analysis slope ratios of the endothermic peak at about 550°C (1.4–2.3) were in the kaolinite range (0.78–2.39).
Feldspar Weathering in Lateritic Saprolite
Authors: Anand R. R. , Gilkes R. J. , Armitage T. M. , Hillyer J. W.
Published: September 2006

Feldspars in granitic saprolite in southwestern Australia have altered to halloysite, kaolinite, and gibbsite with no evidence of noncrystalline material. The secondary minerals are commonly present as intimate mixtures within altered feldspar grains, but discrete zones of gibbsite or halloysite-kaolinite also are present. Variations in the chemical microenvironment within micrometer-size zones in grains apparently controlled the type and distribution of secondary minerals. The alteration of both plagioclase and alkali feldspars involved congruent dissolution by soil solution and crystallization of halloysite, kaolinite, and gibbsite from this solution. Highly altered feldspar grains consist of etched feldspar fragments embedded within a highly porous framework of subhedral to euhedral platy crystals of kaolinite and gibbsite, or of spherical and felted aggregates of halloysite.
Palygorskite and Sepiolite Alteration to Smectite under Alkaline Conditions
Authors: Golden D. C. , Dixon J. B. , Shadfan H. , Kippenberger L. A.
Published: September 2006

The instability of palygorskite and sepiolite under soil conditions was investigated to determine if these fibrous minerals transform directly to smectite under laboratory conditions. The treatment of 100 mg (0.12 mmole) of palygorskite with 1 mmole of NaOH solution (17 ml) at 150°C for 24 hr yielded a smectite. Analcime and smectite were formed when ≥ 3 mmole of NaOH was used. The addition of ≤ 6 mmole NaOH to sepiolite destroyed it gradually. On addition of ≥ 8 mmole NaOH, sepiolite altered to an X-ray amorphous material. In the presence of Al and Si, however, it transformed to smectite and analcime. Transmission electron microscopy, cation-exchange capacity, and X-ray powder diffraction studies of the products suggest that alteration wa. (1) via solution, o. (2) by a structural reorganization wherein the basic 2:1 silicate structural units were unchanged.
Zeolites in Eocene Basaltic Pillow Lavas of the Siletz River Volcanics, Central Coast Range, Oregon
Authors: Keith Terry E. C. , Staples Lloyd W.
Published: September 2006

Zeolites and associated minerals occur in a tholeiitic basaltic pillow lava sequence that makes up part of the Eocene Siletz River Volcanics in the central Coast Range, Oregon. Regional zoning of zeolite assemblages is not apparent; the zeolites formed in joints, fractures, and interstices, although most occur in central cavities of basalt pillows. The zeolites and associated minerals identified, in general order of paragenetic sequence, are smectite, pyrite, calcite (small spheres), thomsonite, natrolite, analcime, scolecite, mesolite, stilbite, heulandite, apophyllite, chabazite, mordenite, calcite (scalenohedra and twinned rhombohedra), laumontite, and amethystine quartz. Common three-mineral assemblages are: natrolite-analcime-stilbite, stilbite-heulandite-chabazite, stilbite-apophyllite-chabazite, and natrolite-mesolite-laumontite.

Alteration of basaltic glass, which was initially abundant, appears to have been an important factor in formation of the zeolites. Isotopic data suggest that zeolitization occurred during a low-temperature (60°–70°C) submarine hydrothermal event, or by reactions of cold (∼10°C) meteoric water with basalt over a long time. The occurrence of different mineral assemblages in cavities of adjacent basalt pillows indicates that these minerals crystallized in closed systems that were isolated as fractures and joints were sealed by deposition of smectite and early zeolites. Although the total chemical composition of the mineral assemblages in cavities is similar, different mineral species formed because of the sensitivity of zeolite minerals to slight variations in physical and chemical conditions within individual cavities.
Phillipsite in Cs Decontamination and Immobilization
Authors: Komarneni Sridhar
Published: September 2006

The Cs selectivity of several natural zeolitic tuffs and synthetic zeolites was measured. Phillipsite-rich tuffs from California and Nevada exchanged 13.5 and 23.7%, respectively, of the Cs present in simulated alkaline defense waste containing 0.00025 M CsCl in 5.5 M NaCl-NaOH solution from the Savannah River Plant, Aiken, South Carolina; whereas mordenite-rich tuffs from Arizona and Nevada exchanged less than 12.7%. The immobilization or fixation of Cs in phillipsite unlike other zeolites can be achieved by heating the zeolite at 600°C for 4 hr in air and collapsing the silicate (aluminate) tetrahedral rings around the Cs ions to produce a Cs-feldspar-type phase. Treatment of the Cs-exchanged phillipsite-rich tuff at 800° to 1000°C resulted in pollucite, CsAlSi2O6, which also “locks in” the Cs ions in its structure. The fixation of Cs exchanged in phillipsite can also be achieved by the formation of pollucite upon hydrothermal treatment at 300°C and 30 MPa pressure within 12 hr. These results suggest that phillipsite-rich tuffs are good candidates for Cs immobilization by heat treatment at low temperatures after they have been used as sorbents in waste decontamination.
The Nascence of Clay Minerals
Authors: Keller W. D.
Published: September 2006

It is a high honor to be invited to give this first Brindley Memorial Lecture. I view it as taking the first step on a ladder, to be followed by suceeeding talks that climb higher to the pinnacle that George Brindley erected for us in clay mineralogy. If George were with us, he would be sitting on the front row, as usual, keeping the speakers and audience "honest" in our deliberations. In turn, I would be privileged to ask him personally to enlighten us with his valued opinion on the many questions I will be asking in this talk.
Interpretation of Solid state 13C and 29Si Nuclear Magnetic Resonance Spectra of Kaolinite Intercalates
Authors: Thompson John G.
Published: September 2006

13C and 29Si nuclear magnetic resonance spectroscopy with magic-angle spinning bas been used to study the short-range ordering and bonding in the structures of intercalates of kaolinite with formamide, hydrazine, dimethyl sulfoxide (DMSO), and pyridine-N-oxide (PNO). The 29Si chemical shift indicated decreasing levels of bonding interaction between the silicate layer and the intercalate in the order: kaolinite: formamide (δ) = -91.9, ppm relative to tetramethylsilane), kaolinite: hydrazine (-92.0), kaolinite: DMSO (-93.1). The 29Si signal of the kaolinite:PNO intercalate (-92.1) was unexpectedly deshielded, possibly due to the aromatic nature of PNO. The degree of three-dimensional ordering of the structures was inferred from the 29Si signal width, with the kaolinite: DMSO intercalate displaying the greatest ordering and kaolinite: hydrazine the least. 13C resonances of intercalating organic molecules were shifted downfield by as much as 3 ppm in response to increased hydrogen bonding after intercalation, and in the kaolinite: DMSO intercalate the two methyl-carbon chemical environments were non-equivalent (δ = 43.7 and 42.5).
Oxygen Isotope Changes During Mica Alteration
Authors: Komarneni Sridhar , Jackson Marion L. , Cole David R.
Published: September 2006

Oxygen isotope analyses (δO18) of micas that were artificially depleted in K+ indicate little or no isotope exchange during the transformation. The oxidation of iron in K-depleted, iron-rich micas by H2O2 treatment resulted in 1.6 to 4.6% decrease in SO18 due to the fact that the equilibrium fractionation factor is less than the initial difference between the starting δO18 of the fluid and micas. The oxygen isotope ratio of a saponite formed by the weathering of phlogopite showed a 9.7% increase in δO18 due to authigenic recrystallization. These results suggest that oxygen isotope ratios can be used to determine the nature of chemical transformation during the weathering of mica to vermiculite and/or smectite.
Direct Measurement of the Relation Between Swelling Pressure and Interlayer Distance in Li-Vermiculite
Authors: Viani Brian E. , Roth Charles B. , Low Philip F.
Published: September 2006

To test the double-layer theory of swelling as applied to layer silicates, the interlayer separation, λ, in a Li-saturated vermiculite from Grouse Creek, Utah, was measured as a function of the swelling pressure, II. An oriented sample of the vermiculite (46-105 μm) was placed in an environmental chamber mounted on an X-ray diffractometer and compressed between N2 gas and a porous membrane in contact with a solution draining to the outside atmosphere. After equilibration at each of several successively higher gas pressures, the c-axis spacing was measured by X-ray diffraction, and the corresponding X was calculated by subtracting the thickness of an elementary silicate layer. The results of these measurements showed that. (1) the relation between II and λ for vermiculite is the same as that previously observed for Na-montmorillonite, i.e., II is an exponential function of 1/λ. (2) the values of II predicted by double-layer theory are much smaller than those observed if the surface potential is assigned the appropriate value; an. (3) the observed relation between II and λ does not have the form predicted by this theory. On the basis of these results, a repulsive force not ascribable to double-layer overlap must be primarily responsible for swelling; this force must result from the in-depth perturbation of the water by the surfaces of the vermiculite layers.
Formation of Highly Selective Cesium-Exchange Sites in Montmorillonites
Authors: Maes André , Verheyden Dirk , Cremers Adrien
Published: September 2006

Ion-exchange sites with very high selectivity for Cs (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:c="http://cambridge.org/core/content" xmlns:core="http://cambridge.org/core" xmlns:m="http://cambridge.org/core/metadata" xmlns:cup="http://contentservices.cambridge.org" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest">ΔGCa2+Cs+ = 40 kJ/eq) similar to illite were generated in a controlled way in montmorillonites b. (1) repeated wetting-drying cycles and b. (2) charge reduction using the Hofmann-Klemen effect. An almost continuous range of sites with selectivities varying from ln <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:c="http://cambridge.org/core/content" xmlns:core="http://cambridge.org/core" xmlns:m="http://cambridge.org/core/metadata" xmlns:cup="http://contentservices.cambridge.org" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest">KCa2+Cs+ = 33 to 5 was observed.
Interaction of Aliphatic Amines with Montmorillonite to Enhance Adsorption of Organic Pollutants
Authors: Wolfe Timothy A. , Demirel Turgut , Baumann E. Robert
Published: September 2006

X-ray powder diffraction studies were performed with propyl-, dodecyl-, and dodecyldiam-monium bentonites saturated with aqueous mixtures of eleven organic pollutants at concentrations of 0.01 to 100%. The alkylammonium salt treatment separated the montmorillonite unit layers, which increased the interlamellar volume and exposed the interlamellar surfaces for adsorption of the organic pollutants. Washing the salt-treated clays with distilled water removed excess, physically adsorbed alkylammonium ions that could interfere with adsorption of the organic pollutants. Adsorption isotherms conducted at organic pollutant concentrations of 100 and 1000 mg/liter indicated the three alkylammonium montmorillonites, especially propylammonium montmorillonite, were effective adsorbents from aqueous solution, but to a lesser extent than adsorbents currently used in the water and wastewater fields.
Adsorption of n-Aliphatic Alcohols from Dilute Aqueous Solutions on RNH3-Montmorillonites. III. Interlamellar Aggregation of the Adsorbate
Authors: Stul Michael S. , De Bock Jozef
Published: September 2006

The large amount of water in the interlamellar space of alkylammonium montmorillonites in aqueous solutions is not fixed by intercalated hexanol or octanol. The hydration of the NH3+-group and the filling of the empty spaces between the carbon chains are responsible for this phenomenon. Hydrogen bonds between the alcohols and the ammonium groups reduce the enthalpy of solution of hexanol and octanol in the interlamellar region at infinite dilution to +17.6 and +12.7 kJ/mole, respectively. Self-association of the alcohols further diminishes the enthalpy of solution at higher alcohol concentration. The interlamellar fixation of the RNH3 cations prevents a micellization as has been obtained in bulk solutions. At a given alcohol concentration smectic type aggregates, i.e., double layers of alcohol molecules, appear as shown by an increase of the basal spacing of the organo-clay complexes. The aggregate formation is favored by a longer chain length of both the cation and the alcohol.
Curves for the Quantification of Mica/Smectite and Chlorite/Smectite Interstratifications by X-ray Powder Diffraction
Authors: Tomita Katsutoshi , Takahashi Hidewo
Published: September 2006

X-ray powder diffraction intensities for many interstratified structures of mica/smectite and chlorite/smectite were calculated by changing combinations of probabilities and transition probabilities of two component layers, respectively. The calculated d-values were plotted with PMS and PSM as the axes of coordinates for mica/smectites (where M is a mica layer and S is a smectite layer). These d-values were then linked into equal d-value curves on a graph. Three equal d-value diagrams ranging from 32.5 to 24.5 Å, from 15.4 to 10.25 Å, and from 3.365 to 3.08 Å were constructed for mica/smectites. Several diagrams were also constructed for mica/glycolated-smectites and chlorite/smectites using the same techniques. PMS and PSM values of mica/smectite producing 26.8- and 12.6-Å reflections in its X-ray powder diffraction pattern were obtained from the coordinates of the intersection of the 26.8-Å line of the first diagram and the 12.6-Å line of the second diagram. The components and stacking parameters of mica/smectites and chlorite/smectites were estimated easily using these diagrams. Interstratified mica/smectites were quantified in the air-dry and glycolated states, and chlorite/smectites in the glycolated state. Stacking parameters obtained by this method agreed well with those obtained by MacEwan's method. Stacking parameters for Reichweite (R=0) and (R= 1) structures were obtained.
Measurement of the Specific Surface Area of Clays by Internal Reflectance Spectroscopy
Authors: Mulla D. J. , Low P. F. , Roth C. B.
Published: September 2006

The specific surface area, S, of a clay is commonly measured by the adsorption of ethylene glycol monoethyl ether (EGME); however, this method can be tedious and time consuming, especially if the clay is saturated with a monovalent, highly hydrated cation. An alternative method for measuring S was developed involving infrared internal reflectance spectroscopy. This method is based on the discovery that the ratio of R1, the reflectance of a clay-HOD mixture at the frequency of O-D stretching, to R2, the reflectance of the mixture at the frequency of H-O-D bending, is linearly related to S. The correlation coefficient between R1/R2 and S, as measured by the adsorption of EGME, was 0.995. Consequently, a calibration curve of R1/R2 versus S was constructed, and the measured values of R1/R2 for any clay-HOD mixture were referred to it for the determination of S. Results were obtained in triplicate in about an hour; hence, this method of determining S is more rapid and convenient than that involving the adsorption of EGME. Moreover, it applies to clays in a natural condition, i.e., swollen in water.
Effect of Solution Conditions on the Proportion and Morphology of Goethite Formed from Ferrihydrite
Authors: Cornell R. M. , Giovanoli R.
Published: September 2006

In alkaline media and at 70°C dilute suspensions of ferrihydrite transformed to goethite between pH 11.2 and 14 and to a mixture of goethite and hematite above and below this pH range. Increasing the temperature of the transformation or the concentration of the suspension reduced the pH range in which goethite alone formed. The morphology of goethite was chiefly a function of the pH of the system. Acicular crystals formed at all pHs and exclusively above pH 12.2. Epitaxial twinned crystals predominated at pHs below 11, and twins free from hematite formed at higher pHs. Increasing the suspension concentration, ionic strength, or temperature extended the pH range over which twinned crystals formed. Electron micrographs showed that twins formed mainly during the initial stage of the transformation, whereas acicular crystals formed over a longer period. Thus, the twins appeared to nucleate in the ferrihydrite; nucleation of acicular particles took place in solution.
Structure and Growth Mechanism of Glauconite as Seen by High-Resolution Transmission Electron Microscopy
Authors: Amouric Marc , Parron Claude
Published: September 2006

The internal fabric of glauconite pellets has been studied by high-resolution transmission electron microscopy (HRTEM) for a better understanding of the glauconitization process. Typical “lamellae” which make up the glauconite pellets showed a spindle-like arrangement of layered crystallite packets. Three main mineral phases were detected: (1) well-ordered glauconite sensu stricto (d(001) = 10 Å) generally in the middle of the spindles; (2) a poorly ordered and undetermined layered-phase “X” with d(001) ~ 12.5 Å, usually sandwiching glauconite such that the interface between the two materials is very sharp; and (3) a noncrystalline or gel-like phase located between the lamellae. A 14-Å smectite-like phase was rarely observed at the periphery of some grains. The glauconite crystallites clearly showed characteristic growth features (e.g., growth steps), whereas the unknown phase X exhibited destabilization characteristics. A structural analysis of the pure glauconite indicates that this dioctahedral mica was present in the IMd (disordered), 1M, and, to a much lesser extent, 2M1 polytypic forms. HRTEM revealed no interlayering of glauconite with the other layered phases. Rather, it appeared to have formed by a layer-growth mechanism at the expense of the unknown phase X which apparently converted into non-crystalline matter before converting to glauconite. The precursor function of the interlamellae “gel” phase during the evolutive process of glauconitization is not understood.
Swelling Pressure Calculated from Mineralogical Properties of a Jurassic Opalinum Shale, Switzerland
Authors: Madsen Fritz T. , Müller-Vonmoos Max
Published: September 2006

Nineteen drill core samples of lower Dogger opalinum shale from wells drilled in connection with a tunnel project near Brugg, northern Switzerland, were investigated. The shale is a well known swelling rock that has caused problems in underground construction work. Swelling pressures determined under constant volume conditions to obtain maximum values were 0.7 to 2.2 N/mm2. The samples contained 37–59% clay-size material and about 35% quartz, 7–18% carbonate minerals, and about 5% feldspar, pyrite, and organic matter. In addition to kaolinite, illite, and chlorite, the clay-size fraction also contained mixed-layer illite/smectite with about 30% swelling layers. The specific surface area of the clay fraction was 135 m2/g. The specific surface charge of the clay (6.7 × 104 esu/cm2), the ion concentration in the pore fluid of the specimen after the swelling test (10−2 mmole/cm3), the valence of the ions in the double layer of the clay particles (+1), and the half distance between the clay plates in the specimen (8–15 Å) allowed the calculation of the swelling pressure for each sample according to the Gouy double layer theory.

The mean value of the calculated swelling pressures was found to be of the same order of magnitude as the measured values, indicating that the technique can be used where cylindrical or rectangular specimens are not available for direct measurement.
Surface Reactions of 3,3′,5,5′-Tetramethyl Benzidine on Hectorite
Authors: McBride M. B.
Published: September 2006

The adsorption and oxidation of 3,3′,5,5′-tetramethyl benzidine (TMB) on hectorite has been investigated using X-ray powder diffraction, ultraviolet-visible spectroscopy, electron spin resonance, and infrared spectroscopy. The molecule adsorbed by cation exchange at low adsorption levels and oxidized to the monomeric radical cation (yellow). At higher adsorption levels, intercalation of TMB occurred in amounts greater than the cation-exchange capacity of the hectorite, and the π-π charge-transfer complex (blue) became much more evident. The TMB monomers appeared to lie flat in the layer silicate interlayers, whereas the molecules in the charge-transfer complexes assumed a near-vertical orientation relative to the surface. The oxidation of adsorbed TMB was probably due to diffusion of O2 to the surface, because the structural Fe3+ content of the hectorite was too low to facilitate a significant quantity of direct Fe3+-TMB electron transfer.