bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral cholera vaccine use in Zanzibar: socioeconomic and behavioural features affecting demand and acceptance
Authors: Schaetti Christian , Hutubessy Raymond , Ali Said M , Pach Al , Weiss Mitchell G , Chaignat Claire-Lise , Khatib Ahmed M
Published: April 2009

Background

Cholera remains a serious public health problem in low-income countries despite efforts in the past to promote oral rehydration therapy as major treatment. In 2007, the majority of worldwide cases (94%) and deaths (99%) were reported from Africa. To improve cholera control efforts in addition to maintaining and improving existing water supply, sanitation and hygiene behaviour measures, the World Health Organization has recently started to consider the use of vaccines as an additional public health tool. To assess this new approach in endemic settings, a project was launched in Zanzibar to vaccinate 50,000 individuals living in communities at high risk of cholera with an oral two-dose vaccine (Dukoral®).

Immunisation programmes in low-income countries have suffered a reduced coverage or were even brought to a halt because of an ignorance of local realities. To ensure the success of vaccination campaigns, implementers have to consider community-held perceptions and behaviours regarding the infectious disease and the vaccine of interest.

The main aim of this study is to provide advice to the Ministry of Health and Social Welfare of Zanzibar regarding routine introduction of an oral cholera vaccine from a socioeconomic and behavioural perspective as part of a long-term development for a sustained cholera prevention strategy.

Methods and design

Qualitative and quantitative methods of health social science research will be applied on four stakeholder levels before and after the mass vaccination campaign. Rapid assessment individual interviews and focus groups will be used to describe cholera- and vaccine-related views of policy makers, health care professionals and community representatives. The cultural epidemiological approach will be employed on the individual household resident level in a repeated cross-sectional design to estimate determinants of anticipated and actual oral cholera vaccine acceptance.

Discussion

The study presented here is designed to inform about people's perceptions regarding cholera and about socioeconomic and behavioural factors determining anticipated and actual oral cholera vaccine acceptance in Zanzibar. Its pre- and post-intervention design using a mixed-methods approach on different stakeholder levels in communities at high risk of cholera outbreaks will ensure the collection of locally valid data relevant for public health action and planning.
Development of reverse phase protein microarrays for the validation of clusterin, a mid-abundant blood biomarker
Authors: Aguilar-Mahecha Adriana , Cantin Christiane , O'Connor-McCourt Maureen , Nantel Andre , Basik Mark
Published: April 2009

Background

Many putative disease blood biomarkers discovered in genomic and proteomic studies await validation in large clinically annotated cohorts of patient samples. ELISA assays require large quantities of precious blood samples and are not high-throughput. The reverse phase protein microarray platform has been developed for the high-throughput quantification of protein levels in small amounts of clinical samples.

Results

In the present study we present the development of reverse-phase protein microarrays (RPPMs) for the measurement of clusterin, a mid-abundant blood biomarker. An experimental protocol was optimized for the printing of serum and plasma on RPPMs using epoxy coated microscope slides and a non-denaturing printing buffer. Using fluorescent-tagged secondary antibodies, we achieved the reproducible detection of clusterin in spotted serum and plasma and reached a limit of detection of 780 ng/mL. Validation studies using both spiked clusterin and clinical samples showed excellent correlations with ELISA measurements of clusterin.

Conclusion

Serum and plasma spotted in the reverse phase array format allow for reliable and reproducible high-throughput validation of a mid-abundant blood biomarker such as clusterin.
Function of anterior talofibular and calcaneofibular ligaments during in-vivo motion of the ankle joint complex
Authors: de Asla Richard J , Kozánek Michal , Wan Lu , Rubash Harry E , Li Guoan
Published: April 2009

Background

Despite the numerous in-vitro studies on the mechanical properties and simulated injury mechanisms of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL), the in-vivo biomechanical behavior of these two ligaments has not yet been described.

Methods

Apparent length of the ATFL and CFL was measured in four ankles in healthy male subjects between 32 and 45 years of age (two left and two right) during a dorsiflexion-plantarflexion and supination-pronation arc of motion using a combined dual-orthogonal fluoroscopic and magnetic resonance imaging technique.

Results

The ATFL elongated from the neutral position at 16.3 +/- 3.0 mm to 20.8 +/- 2.7 mm at maximal plantarflexion and shortened significantly from the neutral position to 13.9 +/- 2.9 mm at maximal dorsiflexion (p = 0.01). The CFL shortened from the neutral position at 28.0 +/- 2.9 mm to 26.6 +/- 2.2 mm at maximal plantarflexion (p = 0.08) and elongated significantly from the neutral position to 29.9 +/- 3.0 mm at maximal dorsiflexion (p = 0.003). The ATFL elongated significantly from 14.8 +/- 2.5 mm at maximal pronation to 17.4 +/- 3.0 mm at maximal supination (p = 0.08). At the same time, the CFL shortened from 31.0 +/- 3.8 mm at maximal pronation to 26.9 +/- 3.6 mm at maximal supination (p = 0.02).

Conclusion

The results showed that the ATFL elongates more during plantarflexion and supination whereas the CFL increases in length with dorsiflexion and pronation. Concurrently, these data also demonstrated the reciprocal function between the two ligaments. While one shortens, the other one elongates. The different elongation of the ATFL and CFL during the same motion arc suggests that under excessive loading conditions the ATFL might be more vulnerable in plantarflexion and supination while the CFL might be more susceptible to injury in dorsiflexion and pronation. Furthermore, in the case of surgical reconstruction the grafts used to reconstruct the two ligaments may need to be tensioned at different positions of the ankle in order to reproduce their natural in vivo function.
Results of a Phase III, Randomized, Placebo-Controlled Study of Sorafenib in Combination With Carboplatin and Paclitaxel As Second-Line Treatment in Patients With Unresectable Stage III or Stage IV Melanoma
Authors: Hauschild Axel , Agarwala Sanjiv S. , Trefzer Uwe , Hogg David , Robert Caroline , Hersey Peter , Eggermont Alexander , Grabbe Stephan , Gonzalez Rene , Gille Jens , Peschel Christian , Schadendorf Dirk , Garbe Claus , O'Day Steven , Daud Adil , White J. Michael , Xia Chenghua , Patel Kiran , Kirkwood John M. , Keilholz Ulrich
Published: April 2009

Purpose

This phase III, randomized, double-blind, placebo-controlled study was conducted to evaluate the efficacy and safety of sorafenib with carboplatin and paclitaxel (CP) in patients with advanced melanoma who had progressed on a dacarbazine- or temozolomide-containing regimen.

Patients and Methods

A total of 270 patients were randomly assigned to receive intravenous paclitaxel 225 mg/m2 plus intravenous carboplatin at area under curve 6 (AUC 6) on day 1 of a 21-day cycle followed by either placebo (n = 135) or oral sorafenib 400 mg (n = 135) twice daily on days 2 to 19. The primary efficacy end point was progression-free survival (PFS); secondary and tertiary end points included overall survival and incidence of best response, respectively.

Results

The median PFS was 17.9 weeks for the placebo plus CP arm and 17.4 weeks for the sorafenib plus CP arm (hazard ratio, 0.91; 99% CI, 0.63 to 1.31; two-sided log-rank test P = .49). Response rate was 11% with placebo versus 12% with sorafenib. Dermatologic events, grade 3 thrombocytopenia, diarrhea, and fatigue were more common in patients treated with sorafenib plus CP versus placebo plus CP.

Conclusion

In this study, the addition of sorafenib to CP did not improve any of the end points over placebo plus CP and cannot be recommended in the second-line setting for patients with advanced melanoma. Both regimens had clinically acceptable toxicity profiles with no unexpected adverse events. A trial of similar design for the first-line treatment of patients with advanced melanoma (intergroup trial E2603) is currently ongoing.
The Effects of a Presurgical Stress Management Intervention for Men With Prostate Cancer Undergoing Radical Prostatectomy
Authors: Parker Patricia A. , Pettaway Curtis A. , Babaian Richard J. , Pisters Louis L. , Miles Brian , Fortier Adoneca , Wei Qi , Carr Danielle D. , Cohen Lorenzo
Published: April 2009

Purpose

This study assessed the short-term and long-term efficacy of a presurgical stress management intervention at reducing mood disturbance and improving quality of life (QOL) in men undergoing radical prostatectomy (RP) for prostate cancer.

Patients and Methods

One hundred fifty-nine men were randomly assigned to a two-session (plus two boosters) presurgical stress management intervention (SM), a two-session (plus two boosters) supportive attention group (SA), or a standard care group (SC). Assessments occurred 1 month before surgery; 1 week before surgery; the morning of surgery; 6 weeks after surgery, and 6 and 12 months after surgery.

Results

Results indicated significant group differences in mood disturbance before surgery (P = .02), such that men in the SM group had significantly less mood disturbance than men in the SC group (P = .006), with no significant differences between the SM and SA or SA and SC groups. In the year after surgery, there were significant group differences on Medical Outcomes Study 36-item short form survey (SF-36) physical component summary (PCS) scores (P = .004); men in the SM group had significantly higher PCS scores than men in the SC group (P = .0009), and there were no significant differences between the SM and SA or SA and SC groups. There were no group effects on prostate-specific QOL or SF-36 mental health scores.

Conclusion

These findings demonstrate the efficacy of a brief presurgical stress management intervention in improving some short-term and long-term outcomes. If these results are replicated, it may be a useful adjunct to standard care for men with prostate cancer undergoing surgery.
Radiotherapy and Adjuvant Trastuzumab in Operable Breast Cancer: Tolerability and Adverse Event Data From the NCCTG Phase III Trial N9831
Authors: Halyard Michele Y. , Pisansky Thomas M. , Dueck Amylou C. , Suman Vera , Pierce Lori , Solin Larry , Marks Larry , Davidson Nancy , Martino Silvana , Kaufman Peter , Kutteh Leila , Dakhil Shaker R. , Perez Edith A.
Published: April 2009

Purpose

To assess whether trastuzumab (H) with radiotherapy (RT) increases adverse events (AEs) after breast-conserving surgery or mastectomy.

Patients and Methods

Patients with early-stage resected human epidermal growth factor receptor 2 (HER-2) –positive breast cancer (BC) were randomly assigned to doxorubicin (A) and cyclophosphamide (C), followed by weekly paclitaxel (T; AC-T-H or AC-TH-H). RT criteria (with or without nodal RT) were postlumpectomy breast or (optional) postmastectomy chest wall. RT of internal mammary nodes was prohibited. RT commenced within 5 weeks after T, concurrently with H. Analysis included 1,503 irradiated patients for RT-associated AEs across treatment arms. Rates of cardiac events (CEs) with and without RT were compared within arms.

Results

No significant differences among arms were found in incidence of acute skin reaction, pneumonitis, dyspnea, cough, dysphagia, or neutropenia. A significant difference occurred in incidence of leukopenia, with higher rates for AC-T-H versus AC-T (odds ratio = 1.89; 95% CI, 1.25 to 2.88). At a median follow-up of 3.7 years (range, 0 to 6.5 years), RT with H did not increase relative frequency of CEs regardless of treatment side. The cumulative incidence of CEs with AC-T-H was 2.7% with or without RT. With AC-TH-H, the cumulative incidence was 1.7% v 5.9% with or without RT, respectively.

Conclusion

Concurrent adjuvant RT and H for early-stage BC was not associated with increased acute AEs. Further follow-up is required to assess late AEs.
Phase I Study of Ixabepilone, Mitoxantrone, and Prednisone in Patients With Metastatic Castration-Resistant Prostate Cancer Previously Treated With Docetaxel-Based Therapy: A Study of the Department of Defense Prostate Cancer Clinical Trials Consortium
Authors: Rosenberg Jonathan E. , Ryan Charles J. , Weinberg Vivian K. , Smith David C. , Hussain Maha , Beer Tomasz M. , Ryan Christopher W. , Mathew Paul , Pagliaro Lance C. , Harzstark Andrea L. , Sharib Jeremy , Small Eric J.
Published: April 2009

Purpose

Mitoxantrone plus prednisone and ixabepilone each have modest activity as second-line chemotherapy in docetaxel-refractory castration-resistant prostate cancer (CRPC) patients. Clinical noncrossresistance was previously observed.

Patients and Methods

Metastatic CRPC patients progressing during or after taxane-based chemotherapy enrolled in a phase I multicenter study of ixabepilone and mitoxantrone administered every 21 days along with prednisone. Ixabepilone and mitoxantrone doses were alternately escalated in a standard 3 + 3 design. Patients were evaluated for toxicity and disease response. Dose-limiting toxicities (DLTs) were defined as treatment related, occurring during cycle 1, and included grade 4 prolonged or febrile neutropenia, thrombocytopenia (grade 4 or grade 3 with bleeding), or ≥ grade 3 nonhematologic toxicity.

Results

Thirty-six patients were treated; 59% of patients experienced grade 3/4 neutropenia. DLTs included grade 3 diarrhea (n = 1), prolonged grade 4 neutropenia (n = 4), and grade 5 neutropenic infection (n = 1). Due to prolonged neutropenia, the highest dose levels were repeated with pegfilgrastim on day 2 of each cycle. The maximum tolerated dose in combination with pegfilgrastim was not exceeded. The recommended phase II dose is mitoxantrone 12 mg/m2 and ixabepilone 35 mg/m2 every 21 days, pegfilgrastim 6 mg subcutaneously day 2, and continuous prednisone 5 mg twice per day. Thirty-one percent of patients have experienced ≥ 50% prostate-specific antigen (PSA) declines, and two experienced objective responses. Of 21 patients treated with mitoxantrone 12 mg/m2 plus ixabepilone ≥ 30 mg/m2, nine (43%) experienced ≥ 50% PSA declines (95% CI, 22% to 66%).

Conclusion

These results suggest that the combination of ixabepilone and mitoxantrone is feasible and active in CRPC and requires dosing with pegfilgrastim.
Phase III Trial of Irinotecan/Cisplatin Compared With Etoposide/Cisplatin in Extensive-Stage Small-Cell Lung Cancer: Clinical and Pharmacogenomic Results From SWOG S0124
Authors: Lara Primo N. , Natale Ronald , Crowley John , Lenz Heinz Josef , Redman Mary W. , Carleton Jane E. , Jett James , Langer Corey J. , Kuebler J. Philip , Dakhil Shaker R. , Chansky Kari , Gandara David R.
Published: April 2009

Purpose

Irinotecan plus cisplatin (IP) improved survival over etoposide plus cisplatin (EP) in Japanese patients with extensive-stage small-cell lung cancer (E-SCLC). To confirm those results and discern the potential role of population-related pharmacogenomics (PG) in outcomes, we conducted a large randomized trial of identical design to the Japanese trial in North American patients with E-SCLC.

Patients and Methods

Patients were randomly assigned to IP (irinotecan 60 mg/m2 on days 1, 8, and 15; cisplatin 60 mg/m2 day 1, every 4 weeks) or EP (etoposide 100 mg/m2 on days 1 through 3; cisplatin 80 mg/m2 day 1, every 3 weeks). Blood specimens for genomic DNA analysis were collected before random assignment in 169 patients.

Results

Of 671 patients, 651 were eligible (324 and 327 patients in the IP and EP arms, respectively). Response rates with IP and EP were 60% and 57%, respectively (P = .56). Median progression-free survival for IP and EP was 5.8 and 5.2 months, respectively (P = .07). Median overall survival for IP and EP was 9.9 and 9.1 months, respectively (P = .71). Severe diarrhea was more common with IP (19% v 3%); severe neutropenia and thrombocytopenia were higher with EP versus IP (68% v 33% and 15% v 4%, respectively). PG analysis showed that ABCB1 (C3435T)T/T (membrane transport) was associated with IP-related diarrhea; UGT1A1 (G-3156A)A/A (drug metabolism) was associated with IP-related neutropenia.

Conclusion

This large North American trial failed to confirm the previously reported survival benefit observed with IP in Japanese patients. Both regimens produced comparable efficacy, with less hematologic and greater gastrointestinal toxicity with IP. These results emphasize the potential importance of PG in interpreting trials of cancer therapy.
Concurrent dual allergen exposure and its effects on airway hyperresponsiveness, inflammation and remodeling in mice
Authors: DiGiovanni Franco A. , Ellis Russ , Wattie Jennifer , Hirota Jeremy A. , Southam David S. , Inman Mark D.
Published: April 2009

Experimental mouse models of asthma have broadened our understanding of the mechanisms behind allergen-induced asthma. Typically, mouse models of allergic asthma explore responses to a single allergen; however, patients with asthma are frequently exposed to, and tend to be allergic to, more than one allergen. The aim of the current study was to develop a new and more relevant mouse model of asthma by measuring the functional, inflammatory and structural consequences of chronic exposure to a combination of two different allergens, ovalbumin (OVA) and house dust mite (HDM), in comparison with either allergen alone. BALB/c mice were sensitized and exposed to OVA, HDM or the combination of HDM and OVA for a period of 10 weeks. Following allergen exposure, airway responsiveness was measured using the flexiVent small animal ventilator, and mice were assessed for indices of airway inflammation and remodeling at both 24 hours and 4 weeks after the final allergen exposure. Mice exposed to the HDM-OVA combination exhibited increased numbers of inflammatory cells in the bronchoalveolar lavage (BAL) when compared with mice exposed to a single allergen. Mice exposed to HDM-OVA also exhibited an elevated level of lung tissue mast cells compared with mice exposed to a single allergen. Following the resolution of inflammatory events, mice exposed to the allergen combination displayed an elevation in the maximal degree of total respiratory resistance (Max RRS) compared with mice exposed to a single allergen. Furthermore, trends for increases in indices of airway remodeling were observed in mice exposed to the allergen combination compared with a single allergen. Although concurrent exposure to HDM and OVA resulted in increased aspects of airway hyperresponsiveness, airway inflammation and airway remodeling when compared with exposure to each allergen alone, concurrent exposure did not result in a substantially more robust mouse model of allergic asthma than exposure to either allergen alone.
A deadlock avoidance strategy for knowledgeable manufacturing systems
Authors: Yang H B , Yan H S
Published: April 2009

Deadlock is a highly unfavourable situation in manufacturing systems, and the development of a deadlock-avoidance policy for resource allocation has received significant attention. Based on finite automata theory, the concept of a distributed deadlock supervisor is proposed to avoid deadlock in knowledgeable manufacturing cell. The proposed approach is insensitive to system scale and improves the efficiency of the modelling and operation of automata. The auto-correlation operation is presented, and the knowledgeable manufacturing cell is divided into a number of submodules, and the corresponding distributed deadlock supervisors are constructed. A state backtrack algorithm is given to ensure full reachability of deadlock supervisor, and thus a deadlock-free strategy for the knowledgeable manufacturing cell is obtained. This can be used to monitor the status of the knowledge manufacturing cell in real-time and guarantees deadlock-free running of the system. A case study is presented to demonstrate the feasibility and effectiveness of the proposed strategy.
Line segment fabrication model analysis of near-field photolithography
Authors: Lin Z-C , Yang C-B
Published: April 2009

This paper proposes an integral formula for the exposure energy density during the movement of a workpiece to enable the exposure energy distribution on a photoresist surface to be investigated. The photoresist is divided into finite nodes and the relative concentration variation of the photoactive compound at each finite node of photoresist interior layer is calculated. Also, the average full-width-at-half-maximum (FWHM) during near-field photolithography is calculated. The average FWHM of a line segment fabricated experimently using near-field photolithography is 215.7 nm at a depth of 10.3 nm.
A simplified model for natural-gas vehicle catalysts with honeycomb and foam substrates
Authors: Tsinoglou D N , Eggenschwiler P Dimopoulos , Thurnheer T , Hofer P
Published: April 2009

A mathematical model is developed for the simulation of the chemical and transport phenomena in three-way catalysts for natural-gas vehicles, with honeycomb and foam substrates. The chemical phenomena are modelled on the basis of a simplified approach, which assumes that pollutant conversion is governed by oxygen storage and release dynamics. The transport phenomena, i.e. heat transfer, gas-phase mass transfer, washcoat diffusion, and pressure drop, are modelled on the basis of correlations adapted from the literature. The model is validated using lambda scan tests and a cold-start driving cycle, carried out with a honeycomb catalyst and a ceramic foam catalyst. The experimental data show a decline in methane conversion for lean mixtures, which is modelled by an inhibition term of methane oxidation from nitric oxide. The proposed model may capture the performance of both substrates with sufficient accuracy, both under cold-start and under hot-mode conditions. The model-based comparison of the two substrates shows that the ceramic foam presents inferior carbon monoxide conversion in the extra-urban part of the cycle. Although the gas-phase mass transfer in the ceramic foam is faster than with the honeycomb monolith, diffusion in the washcoat pores is much slower. As a result, the mass-transfer-limited conversion efficiency of the foam is lower. This is primarily attributed to the higher washcoat thickness of the foam sample tested.
Contribution to the definition of the torsional stiffness of the crankshaft of a diesel engine used in heavy-duty vehicles
Authors: Milašinović A , Filipovic I , Hribernik A
Published: April 2009

A new approach for determining the torsional stiffness coefficient of an equivalent mechanical system's crankshaft section, which can be used to study torsional vibrations, is presented. In order to describe mathematically the torsional vibration of a reciprocating engine, it is necessary to replace the actual system consisting of the crankshaft, connection rods, and reciprocating elements by an equivalent system, usually modelled as a lumped-parameter system. The present authors, in accordance with their personal experiences, have found the determination of the equivalent system's parameters to be a very important and demanding task, especially in regard to torsional stiffness and damping coefficients. This paper analyses all aspects of determining a crankshaft section's torsional stiffness coefficient, which is the most complex element in a torsional dynamic model of a crankshaft. The method analysing the crank torsional stiffness coefficient determination has been given in the literature. The real boundary conditions of the crankshaft are emphasized as a problem, which makes determination of the torsional stiffness coefficient of the crankshaft section even more difficult. An indirect method for this determination is explained in this paper. By using this method, the real boundary conditions of the crankshaft of the diesel engine used in heavy-duty vehicles are considered, and the results obtained are reliable and confirmed by experiment.
A novel in-vehicle real-time brake-monitoring system
Authors: Fumi D E , Sultan I A
Published: April 2009

The design of vehicle brake systems involves optimizing a large number of competing parameters. In order to find an appropriate balance of properties, it is important to have a good picture of the range of operating conditions that the system will operate under. Obtaining such information for a large range of driving conditions requires recording data over a long period of time from a number of vehicles under various driving conditions. In this paper, a proposed data acquisition system has been designed, constructed, and implemented to measure and to store in real time the performance-related parameters of brake systems.

The system proposed here to monitor brake performance employs a small embedded personal computer together with a number of peripheral cards as its basis. As a part of the validation process, recordings have been made of some long-term test sequences during a brake development programme. The results, which would be considered representative of normal confident driving, are given and discussed at the end of the paper. These results are used to monitor brake performance and do offer valuable guidance for future brake design projects.
Significance of phyllosilicate mineralogy and mineral chemistry in an epithermal environment. Insights from the palai-islica Au-Cu deposit (Almería, SE Spain)
Authors: Carrillo-Rosúa Javier , Morales-Ruano Salvador , Esteban-Arispe Iñaki , Fenoll Hach-Alí Purificación
Published: April 2009

Phyllosilicate mineralogy is key to understanding hydrothermal processes within accepted epithermal deposit models but little information has been published about the mineral chemistry of epithermal deposits. X-ray diffraction, optical and electronic microscopy (scanning and transmitted), electron microprobe, and Fourier transform infrared spectroscopy were used in this work to study phyllosilicates in the Palai-Islica Au-Cu epithermal, volcanic-hosted deposit, in order to link phyllosilicate mineralogy and mineral chemistry to ore genesis. Different phyllosilicate assemblages are characteristic of two types of mineralization, and related hydrothermal alteration. Chlorite and mica appear in polymetallic quartz veins with sulfides, and in the related chloritic and sericitic hydrothermal alteration. These minerals have notable textural and chemical differences (i.e. Fe/(Fe+Mg), Si and Al in chlorite and illitic and phengitic components in mica) amongst veins and altered rocks, revealing different genetic conditions. These chemical features also distinguish propylitic and regional, non ore-related, low-temperature alteration. Hot hydrothermal fluids of near-neutral pH are responsible for vein mineralization and alteration. Illite, interstratified illite-smectite, kaolinite, and pyrophyllite are characteristic, with a distribution pattern by zones, of the intermediate argillic and advanced argillic alteration around areas of silicification. In the latter, native gold appears associated with interstratified illite-smectite, suggesting a relatively low-temperature formation. Hot, low-pH fluids are responsible for this mineralization and alteration assemblage. The present study contributes to epithermal models showing the co-existence of two different alteration styles in the same hydrothermal system.
X-Ray diffraction line-broadening study on two vibrating, dry-milling procedures in kaolinites
Authors: Pardo Pablo , Bastida Joaquín , Serrano Francisco J. , Ibáñez Rafael , Kojdecki Marek A.
Published: April 2009

Due to the great technological importance of the microstructure of kaolinite, characterizing its evolution during dry milling of kaolin and analyzing the microstructural information obtained from different methods were the main aims of this work. The microstructural alteration of kaolinite is evaluated by X-ray diffraction and electron microscopy methods, comparing the results obtained and analyzing the correlations between them. The Warren-Averbach and Voigt-function methods of X-ray diffraction microstructural analysis have been applied successfully to the study of the effects of two different, vibrating-cup dry-milling configurations in the microstructure of kaolinite from the reflections corresponding to (001) diffracting planes. The crystallite-size estimates obtained from the two methods correlate well. Field emission scanning electron microscopy measurements of kaolinite particle thickness are in good agreement with the crystallite size estimated by the two methods. The Warren-Averbach method also provided estimates of the contribution to line broadening. Vibrating-cup milling has been proved to be a more efficient method of strain comminution of kaolinites than other milling techniques, reaching extensive microstructural degradation within seconds.
Rapid and direct synthesis of spherical organotalc
Authors: Jaber Maguy , Gaslain Fabrice O. M. , Miehé-Brendlé Jocelyne
Published: April 2009

Organotalcs, in which organic moieties are covalently bonded to Si atoms belonging to the tetrahedral sheets, are usually prepared by a sol-gel process starting from ethanolic solution of Mg nitrate, organo-alcoxysilanes, and aqueous sodium hydroxide solution. In this case, gypsum-like particles are obtained. In this work, evaporation-induced self-assembly within aerosols was used for the first time in order to prepare organotalc spheres. These hybrid lamellar materials can be used as environmental barriers, as polymer fillers, and as catalytic supports. Using octyltriethoxysilane as a source of Si, spherical particles with sizes ranging from 20 nm to 1 µm are obtained. X-ray diffraction and transmission electron microscopy images show that the d001 value equals 2.8 nm meaning that, in this case, organic moities are either alternatively distributed or identically tilted in the interlayer space. Compared to the classical synthesis at room temperature or in autoclaves, and besides being a continuous process, the reaction time is reduced to several minutes instead of hours. Homogeneous forms are obtained by aerosol whereas irregular shapes are obtained in the classical synthesis.
Magnetic enhancement during the crystallization of ferrihydrite at 25 and 50°C
Authors: Cabello E. , Morales M. P. , Serna C. J. , Barrón V. , Torrent J.
Published: April 2009

Soil formation usually results in an increase in magnetic susceptibility. The magnetic properties of the products of transformation of ferrihydrite, a typical precursor of other soil Fe oxides, were examined in the present work. Synthetic 2-line ferrihydrite was aged at two temperatures (25 and 50°C) and two different relative humidities (80 and 100%) in the presence of silicate, phosphate, citrate, and tartrate as adsorbed ligands (molar anion/Fe ratio = 1–3%). The ligands delayed or prevented the transformation of ferrihydrite to hematite. The magnetic susceptibility of the ferrihydrite transformation products increased with aging, the rate of increase depending on the type of ligand added and its concentration. The largest increase in magnetic susceptibility, sixfold, was obtained with ferrihydrite in a citrate/Fe ratio of 1%, after 1500 days. The resulting magnetic products exihibited superparamagnetic behavior at room temperature and high coercivity at 5 K. The formation of an intermediate ferrimagnetic phase in the ferrihydrite-to-hematite transformation might explain the magnetic enhancement observed in many aerobic soils lacking other sources of magnetic minerals.
Hydrogen bonding and vibrational spectra in kaolinite-dimethylsulfoxide and -dimethylselenoxide intercalates — A solid-state computational study
Authors: Scholtzová Eva , Smrčok L’ubomír
Published: April 2009

The aims of this study were to obtain accurate structural information on the dimethyl sulfoxide (DMSO) and dimethylselenoxide (DMSeO) kaolinite intercalates, paying close attention to the hydrogen-bond geometries, and to provide a detailed interpretation of the individual vibrational modes of intercalates under study and relate their energies to the formation of the hydrogen bonds. Accurate positions of all the atoms in the structures of kaolinite:dimethylsulfoxide (K:DMSO) and kaolinite:dimethylselenoxide (K:DMSeO) intercalates have been obtained by the total energy minimization in solid state at density functional theory (DFT) level of the theory. The bond distances and angles in the kaolinite 1:1 layer are in good agreement with those reported in the most recent single-crystal refinement of kaolinite. Computed geometries of DMSO and DMSeO agree well with the high-quality diffraction data and independent theoretical ab initio calculations. The organic molecules are fixed in the interlayer space mainly by three moderately strong O-H⋯O hydrogen bonds, of different strengths, with the O⋯O contact distances being within 2.739–2.932 Å (K:DMSO) and 2.681–2.849 Å (K:DMSeO). Substantially weaker C-H⋯O and O-H⋯S(Se) contacts play only a supporting role. The optimized atomic coordinates were used to calculate the individual vibrational modes between 0 and 4000 cm−1. The maximum red shifts of the OH-stretching modes caused by the formation of the O-H⋯O hydrogen bonds were 407 cm−1 (K-DMSO) and 537 cm−1 (K-DMeSO), respectively. The Al-O-H bending modes are spread over the large interval of 100–1200 cm−1, but the dominant contributions are concentrated between 800 and 1200 cm−1. Theoretically calculated energies of the OH- and CH-stretching modes show good agreement with the previously published figures obtained from the infrared and Raman spectra of these intercalates.
A new massive deposit of allophane raw material in Ecuador
Authors: Kaufhold Stephan , Kaufhold Annette , Jahn Reinhold , Brito Salomón , Dohrmann Reiner , Hoffmann Rainer , Gliemann Hartmut , Weidler Peter , Frechen Manfred
Published: April 2009

In Ecuador, DINAGE (known today as the Servicio Geológico Nacional) and the German Federal Institute for Geosciences and Natural Resources have discovered a huge allophane deposit covering an area of >4000 km2. This study presents the results from an investigation of a 16-m thick vertical sequence from this deposit, supposedly the weathering product of two different volcanic ash deposits. In particular, the distribution of alkali metals within the uppermost layer indicates that the weathering process is still ongoing.

According to the mineralogical composition, an allophane-rich layer (allophane facies) could be distinguished from the underlying halloysite-rich layer (halloysite facies). A 2-m thick transition zone is characterized by the presence of gibbsite and intermediate specific surface area values. Only a few imogolite fibers could be identified (by scanning electron microscopy), indicating the dominance of allophane over imogolite in the allophane facies. Single allophane particles were investigated by atomic force microscopy, though this method was less accurate than transmission electron microscopy with respect to the determination of the primary particle diameter. Carbon isotope analysis (14C) suggested an age of ∼20,000 y for the allophane layer.

Within the allophane facies, a 4-m thick layer occurs containing 70–80 wt.% allophane with an N2-BET specific surface area of >300 m2/g. Based on infrared and energy-dispersive X-ray diffraction measurements, an Al/Si ratio of 1.3–1.4 was established for this allophane, which is between Al-rich and Si-rich allophane. The allophane layer may be of economic value due to the large allophane content, the small amount of organic matter, and the significant thickness of the deposit.
Extraction of diagenetic and detrital ages and of the 40Kdetrital/40Kdiagenetic ratio from K-Ar dates of clay fractions
Authors: Szczerba Marek , Środoń Jan
Published: April 2009

Illite age analysis (IAA) is a classical method for extracting diagenetic and detrital ages from mixed ages measured by K-Ar. This approach is based on measuring the masses of diagenetic and detrital illitic components in a few different grain-size fractions of one rock sample and measuring the mixed ages of these fractions. The 1Md illitic polytype is usually considered to be diagenetic, while 2M1 is considered detrital. A plot of the function: exp(λt)−1 (where t is time and λ is the decay constant) vs. weight percent of the detrital fraction is constructed. On the basis of linear extrapolation to end-member fractions, the diagenetic and the detrital age is obtained. This approach does not take into account various K contents in different polytypes (%Kdetrital and %Kdiagenetic). In order to do that, the detrital mass fraction (wt.%detrital) should be recalculated into the percentage of detrital K (%Id(K)):

Analytical constraint of the K content of different polytypes is very difficult, so a new approach to this problem has been developed. In the present study, the plot of 40Ar*/40K vs. %Id(K) for a precisely determined ratio of 40Kdetrital/40Kdiagenetic was observed to be linear. On the basis of this observation, a computer program, MODELAGE, was written in the Java programming language using as input a few measured detrital illite mass fractions along with the mixed K-Ar ages of the relevant grain fractions. It then calculates the end-member ages and the 40Kdetrital/40Kdiagenetic ratio using genetic algorithms.

The errors in diagenetic and detrital illite mass-fraction determination mean that the 40Kdetrital/40Kdiagenetic ratio and the end-member ages can be evaluated only with some uncertainty. The best results are obtained if the measured mass fractions represent a relatively broad range. Constraining one of the unknowns (particularly the 40Kdetrital/40Kdiagenetic ratio) improves the results significantly.

Evaluation of data obtained from the literature using the proposed approach leads to the conclusion that the 40Kdetrital/40Kdiagenetic ratio is often >1.00, and some of 1Md illite polytype materials may be of detrital origin. If this is not the case, if a broad range of mass fractions is covered, and if the differences between end-member ages are relatively small, IAA analysis still gives appropriate results, even if the true 40Kdetrital/40Kdiagenetic ratio is different from 1.00.
Clay profiling: The classification of montmorillonites
Authors: Emmerich Katja , Wolters Felicitas , Kahr Guenter , Lagaly Gerhard
Published: April 2009

Montmorillonites, with the general composition

where x = ξ = 0.2–0.6, x = y+z, and y≪z, vary widely in composition and structure. The commonly used classification into five montmorillonite and two beidellite groups for the solid-solution sequence does not allow an unambiguous classification with respect to structural features and the resulting properties.

The smectite structure reveals five features that allow an unambiguous description of a sample: (1) identification as either a dioctahedral or a trioctahedral smectite; (2) layer charge; (3) charge distribution between tetrahedral and octahedral sheets; (4) cation distribution within the octahedral sheet; and (5) Fe content. In addition, the nature of interlayer cations should be given as they influence certain properties of montmorillonites. Analytical methods are now available to measure and determine these structural features. Therefore, a precise classification for montmorillonites requires determination of layer charge and exchangeable cations, analysis of chemical composition, and thermal analysis (to determine the octahedral structure), in addition to X-ray diffraction analysis.

A comprehensive classification of montmorillonites based on these parameters is proposed. Ninety-six structural variations (expressed by systematic names) theoretically exist within the montmorillonite-beidellite series. Descriptive names can be used to elucidate the macroscopic properties of the montmorillonite samples in question.
A comprehensive characterization of dioctahedral smectites
Authors: Wolters Felicitas , Lagaly Gerhard , Kahr Guenter , Nueesch Rolf , Emmerich Katja
Published: April 2009

The term ‘montmorillonite’ encompasses a wide range of chemical compositions and structures. Comprehensive and reliable characterization is essential for unambiguous classification. Twenty eight purified, Na-exchanged smectites (<0.2 µm) were characterized by layer-charge measurement using the alkylammonium method, by cation exchange capacity (CEC) measurement with Cu-triethylenetetramine, by determination of the chemical composition using X-ray fluorescence analysis, by calculation of the structural formula following determination of the octahedral structure (trans-vacant vs. cis-vacant) by simultaneous thermal analysis, and by X-ray diffraction analysis. Mössbauer spectroscopy was applied to determine the oxidation state and coordination of Fe and changes thereof during purification of the source materials.

The charge derived from chemical composition was considerably greater (by up to 30%) than the measured layer charge. The independently measured layer charge was used to calculate the structural formula. The measured CEC values, comprising the permanent charges and the pH-dependent edge charges, were consistent with measured layer charge but not with layer charge derived from the chemical composition. Therefore, the structural formula of smectites should be calculated using the measured layer charge.

The dehydroxylation temperature, which conveys information about the structure of the octahedral sheet, was correlated to the amount of Mg and Fe3+ and the location of charges. No relationship was found among the dehydroxylation temperature and the mean layer charge or the Mg content. In contrast, a clear relationship was observed between the Fe content and the dehydroxylation temperature. Montmorillonites with an Fe content <0.3/f.u. are cis-vacant and those containing Fe3+ > 0.3 mol/f.u. are trans-vacant, mostly with additional cis-vacancies. Tetrahedral substitution also appeared to be a function of the number of trans-vacancies.

The parameters analyzed provide the basis for a new descriptive classification system.
Estabelecimento, multiplicação e alongamento in vitro de Eucalyptus benthamii Maiden & Cambage x Eucalyptus dunnii Maiden
Authors: Brondani Gilvano Ebling , Dutra Leonardo Ferreira , Grossi Fernando , Wendling Ivar , Hornig Jefferson
Published: April 2009

Neste trabalho foram testadas diferentes concentrações de cloro ativo (NaOCl) na assepsia de explantes para o estabelecimento in vitro, bem como benzilaminopurina (BAP) e ácido naftalenoacético (ANA) para a multiplicação e alongamento de Eucalyptus benthamii x Eucalyptus dunnii. As minicepas fornecedoras de propágulos para introdução in vitro foram conduzidas em minijardim clonal sob sistema semi-hidropônico. Segmentos nodais dos clones H12, H19 e H20 foram desinfestados com 0,5; 1,0; 1,5; e 2,0% (v/v) de cloro ativo durante 10 min e inoculados em meio de cultura MS. Na obtenção de brotações múltiplas, utilizou-se o meio de cultura ½MS suplementado com 0; 0,25; 0,50; 0,75; e 1,0 mg L-1 de BAP. Na fase de alongamento, utilizou-se o meio de cultura ½MS com 0; 0,25; 0,50; 0,75; e 1,0 mg L-1 de ANA. Não houve interação entre os fatores estudados, obtendo-se 45%, 46% e 66% de estabelecimento do clone H12, H19 e H20, respectivamente. A concentração de BAP que resultou na maior proliferação de gemas axilares para o clone H12 aos 60 dias foi estimada na faixa de 0,25 e 0,30 mg L-1. Aos 60 dias, a faixa entre 0,25 e 0,75 mg L-1 de ANA promoveu o maior número de brotações alongadas do clone H12.
Morfogênese in vitro de nim a partir de explantes cotiledonares
Authors: Rodrigues Marcelo , Paiva Renato , Nogueira Rairys Cravo , Martinotto Cristiano , Silva Júnior Jessé Marques
Published: April 2009

Azadirachta indica A. Juss, popularmente conhecido como nim, é uma espécie arbórea que se destaca por possuir substâncias de ação inseticida, fungicida, bactericida e nematicida. Sementes de nim foram inoculadas em meio de cultura WPM (Wood Plant Medium) contendo diferentes concentrações de ácido giberélico (GA3) (0; 3,0; 6,0; 9,0; e 12,0 mg L-1). Após 30 dias, cotilédones obtidos a partir de plântulas germinadas in vitro foram inoculados em meio WPM suplementado com ácido 2,4-diclorofenoxiacético (2,4-D) (0,0; 1,0; 2,0; e 3,0 mg L-1) e, ou, 6-benzilaminopurina (BAP) (0,0; 1,0; 2,0; e 3,0 mg L-1). As culturas foram incubadas no escuro, a 28 ºC. Os calos formados foram avaliados com base na sua coloração e textura, e três subcultivos foram realizados mensalmente em meio WPM contendo 2,0 mg L-1 BAP, na presença de luz. A cada 30 dias, avaliou-se o número de brotos formados a partir dos calos subcultivados. Entre os meios testados, o mais apropriado para germinação in vitro de nim foi o WPM na ausência de GA3. Explantes cotiledonares cultivados em WPM suplementado com 2,0 mg L-1 de BAP promoveram a maior formação de calos com potencial morfogênico. Quando esses calos foram transferidos para meio de composição similar, obteve-se alta formação de brotações até o terceiro subcultivo.
Crescimento e teores de boro em plantas de eucalipto (Eucalyptus citriodora) cultivadas em dois latossolos sob influência de doses de boro e disponibilidade de água
Authors: Ramos Sílvio Júnio , Faquin Valdemar , Ferreira Rose Myrian Alves , Araújo Josinaldo Lopes , Carvalho Janice Guedes de
Published: April 2009

Este trabalho objetivou avaliar o efeito da aplicação de doses de boro no crescimento de Eucalyptus citriodora em um Latossolo V ermelho-Escuro e um Latossolo Vermelho-Amarelo, submetidos a diferentes tensões hídricas. O experimento foi conduzido em casa de vegetação, no Departamento de Ciência do Solo da Universidade Federal de Lavras, em Lavras, MG, usando-se vasos com três dm³ de solo. Utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 2 x 2, sendo cinco doses de B (0,00; 0,25; 0,75; 2,25; e 6,25 mg kg-1); e dois tipos de Latossolo: Latossolo Vermelho-Escuro (LE) e Latossolo Vermelho-Amarelo (LV) e duas tensões hídricas (-0,033 e -0,010 MPa), com quatro repetições. Os resultados indicaram que tanto o LV quanto o LE, nas suas condições naturais, não supriram as exigências de B em Eucalyptus citriodora. Contudo, os maiores incrementos na produção de matéria seca das plantas foram observados em baixas doses de B aplicadas. A umidade do solo é um fator importante no aproveitamento de B do solo pelo Eucalyptus citriodora.
Diagnóstico da fauna silvestre em empresas florestais brasileiras
Authors: Medeiros Giovanna Debortoli , Silva Elias , Martins Sebastião Venâncio , Feio Renato Neves
Published: April 2009

Com o objetivo de conhecer a situação atual da fauna silvestre em empresas florestais brasileiras, foram pesquisadas 42 razões sociais, entre Associadas e Co-Participantes da Sociedade de Investigações Florestais (SIF), as quais possuem plantios florestais próprios. As informações foram obtidas com base em questionário enviado às referidas empresas, via correio eletrônico, sendo as respostas obtidas também por esse mecanismo. Entre os vários resultados, destaca-se o fato de que 90,9% das empresas associadas já realizaram levantamentos qualitativos da fauna silvestre. No entanto, de modo geral há notória carência de infra-estrutura nas empresas pesquisadas para atender a trabalhos específicos de manejo e conservação da fauna silvestre.