bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical relevance of Aspergillus isolation from respiratory tract samples in critically ill patients
Authors: Vandewoude Koenraad H , Blot Stijn I , Depuydt Pieter , Benoit Dominique , Temmerman Werner , Colardyn Francis , Vogelaers Dirk 
Published: February 2006

Abstract
Introduction
The diagnosis of invasive pulmonary aspergillosis, according to the criteria as defined by the European Organisation for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG), is difficult to establish in critically ill patients. The aim of this study is to address the clinical significance of isolation of Aspergillus spp. from lower respiratory tract samples in critically ill patients on the basis of medical and radiological files using an adapted diagnostic algorithm to discriminate proven and probable invasive pulmonary aspergillosis from Aspergillus colonisation.

Methods
Using a historical cohort (January 1997 to December 2003), all critically ill patients with respiratory tract samples positive for Aspergillus were studied. In comparison to the EORTC/MSG criteria, a different appreciation was given to radiological features and microbiological data, including semiquantitative cultures and direct microscopic examination of broncho-alveolar lavage samples.

Results
Over a 7 year period, 172 patients were identified with a positive culture. Of these, 83 patients were classified as invasive aspergillosis. In 50 of these patients (60%), no high risk predisposing conditions (neutropenia, hematologic cancer and stem cell or bone marrow transplantation) were found. Typical radiological imaging (halo and air-crescent sign) occurred in only 5% of patients. In 26 patients, histological examination either by ante-mortem lung biopsy (n = 10) or necropsy (n = 16) was performed, allowing a rough estimation of the predictive value of the diagnostic algorithm. In all patients with histology, all cases of clinical probable pulmonary aspergillosis were confirmed (n = 17). Conversely, all cases classified as colonisation had negative histology (n = 9).

Conclusion
A respiratory tract sample positive for Aspergillus spp. in the critically ill should always prompt further diagnostic assessment, even in the absence of the typical hematological and immunological host risk factors. In a minority of patients, the value of the clinical diagnostic algorithm was confirmed by histological findings, supporting its predictive value. The proposed diagnostic algorithm needs prospective validation.
Effect of oral decontamination with chlorhexidine on the incidence of nosocomial pneumonia: a meta-analysis
Authors: Pineda Lilibeth A , Saliba Ranime G , El Solh Ali A 
Published: February 2006

Abstract
Introduction
Nosocomial pneumonia is a significant cause of in-hospital morbidity and mortality. Oral care interventions have great potential to reduce the occurrence of nosocomial pneumonia. Studies using topical antiseptic agents yielded mixed results. We hypothesized that the use of chlorhexidine for oral decontamination would reduce the incidence of nosocomial pneumonia in patients requiring mechanical ventilation.

Methods
This study is a meta-analysis of randomized controlled trials assessing the effect of chlorhexidine on the incidence of nosocomial pneumonia. Data sources were Medline, EMBASE, Cochrane library, citation review of relevant primary and review articles, and contact with expert informants. Out of 1,251 articles screened, 4 randomized, controlled trials were identified that included a total of 1,202 patients. Descriptive and outcome data were extracted by two reviewers independently. Main outcome measures were the incidence of nosocomial pneumonia, and mortality. A random effects model was used.

Results
The incidence of nosocomial pneumonia in the control group was 7% (41 out of 615) compared to 4% (24 out of 587) in the treatment group. Gram-negative bacteria accounted for 78% of the total isolates, with Pseudomonas aeruginosa being the most frequently isolated pathogen irrespective of the intervention provided. Duration of mechanical ventilation and intensive care unit length of stay were comparable between the two groups. Overall, the use of oral decontamination with chlorhexidine did not affect the incidence of nosocomial pneumonia (odds ratio of 0.42; 95% confidence interval 0.16–1.06) or the mortality rate (odds ratio 0.77, 95% confidence interval 0.28–2.11).

Conclusion
The use of oral decontamination with chlorhexidine did not result in significant reduction in the incidence of nosocomial pneumonia in patients who received mechanical ventilation, nor altered the mortality rate. The lack of benefit may reflect the few studies conducted in this area. Future trials should focus on a combination strategy of mechanical and pharmacological interventions.
Natriuretic peptide testing for the evaluation of critically ill patients with shock in the intensive care unit: a prospective cohort study
Authors: Januzzi James L , Morss Alexander , Tung Roderick , Pino Richard , Fifer Michael A , Thompson B Taylor , Lee-Lewandrowski Elizabeth 
Published: February 2006

Abstract
Introduction
Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is useful in evaluating heart failure, but its role in evaluating patients with shock in the intensive care unit (ICU) is not clear.

Method
Forty-nine consecutive patients in four different ICUs with shock of various types and with an indication for pulmonary artery catheter placement were evaluated. Analyses for NT-proBNP were performed on blood obtained at the time of catheter placement and results were correlated with pulmonary artery catheter findings. Logistic regression identified independent predictors of mortality.

Results
A wide range of NT-proBNP levels were observed (106 to >35,000 pg/ml). There was no difference in median NT-proBNP levels between patients with a cardiac and those with a noncardiac origin to their shock (3,046 pg/ml versus 2,959 pg/ml; P = 0.80), but an NT-proBNP value below 1,200 pg/ml had a negative predictive value of 92% for cardiogenic shock. NT-proBNP levels did not correlate with filling pressures or hemodynamics (findings not significant). NT-proBNP concentrations were higher in patients who died in the ICU (11,859 versus 2,534 pg/ml; P = 0.03), and the mortality rate of patients in the highest log-quartile of NT-proBNP (66.7%) was significantly higher than those in other log-quartiles (P < 0.001); NT-proBNP independently predicted ICU mortality (odds ratio 14.8, 95% confidence interval 1.8–125.2; P = 0.013), and was superior to Acute Physiology and Chronic Health Evaluation II score and brain natriuretic peptide in this regard.

Conclusion
Elevated levels of NT-proBNP do not necessarily correlate with high filling pressures among patients with ICU shock, but marked elevation in NT-proBNP is strongly associated with ICU death. Low NT-proBNP values in patients with ICU shock identifed those at lower risk for death, and may be useful in excluding the need for pulmonary artery catheter placement in such patients.
Nonrandom divergence of gene expression following gene and genome duplications in the flowering plant Arabidopsis thaliana
Authors: Casneuf Tineke , De Bodt Stefanie , Raes Jeroen , Maere Steven , Van de Peer Yves 
Published: February 2006

Abstract
Background
Genome analyses have revealed that gene duplication in plants is rampant. Furthermore, many of the duplicated genes seem to have been created through ancient genome-wide duplication events. Recently, we have shown that gene loss is strikingly different for large- and small-scale duplication events and highly biased towards the functional class to which a gene belongs. Here, we study the expression divergence of genes that were created during large- and small-scale gene duplication events by means of microarray data and investigate both the influence of the origin (mode of duplication) and the function of the duplicated genes on expression divergence.

Results
Duplicates that have been created by large-scale duplication events and that can still be found in duplicated segments have expression patterns that are more correlated than those that were created by small-scale duplications or those that no longer lie in duplicated segments. Moreover, the former tend to have highly redundant or overlapping expression patterns and are mostly expressed in the same tissues, while the latter show asymmetric divergence. In addition, a strong bias in divergence of gene expression was observed towards gene function and the biological process genes are involved in.

Conclusion
By using microarray expression data for Arabidopsis thaliana, we show that the mode of duplication, the function of the genes involved, and the time since duplication play important roles in the divergence of gene expression and, therefore, in the functional divergence of genes after duplication.
FTIR investigation of the evolution of the octahedral sheet of kaolinite-smectite with progressive kaolinization
Authors: Cuadros Javier , Dudek Teresa 
Published: February 2006

AbstractTwenty two samples were studied to investigate the nature and evolution mechanism of mixed-layer kaolinite-smectite (K-S). We examined the <2 µm or <0.2 µm fraction of K-S formed by hydrothermal and hypergenic alteration of volcanic material. The samples are from three localities: 20 specimens from a Tortonian clay deposit in Almería, Spain; one specimen from weathered Eocene volcanic ash from the Yucatan Peninsula, Mexico; and one sample from a weathered Jurassic bentonite from Northamptonshire, England. The samples were studied using chemical analysis, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The XRD patterns of the oriented, glycolated mounts were modeled using NEWMOD and the proportion of smectite and kaolinite layers was determined, ranging between 0 and 80% kaolinite. The analysis of the OH-stretching region of the FTIR spectra at different temperatures (180–550°C) showed the progressive dehydroxylation of kaolinite domains and, perhaps, of smectite domains, but no detailed information could be obtained about the sequential OH loss in different cation environments. The abundance and short-range ordering of the octahedral cations were studied using the OH-bending bands. The chemical and FTIR-estimated octahedral cation abundances were broadly similar. Aluminum showed a tendency to mix with Fe and Mg rather than to form AlAl pairs. Al-for-Mg substitution accompanying kaolinization was evident from the increase in AlAl pairs and decrease in AlMg pairs. Iron is retained in the structure. No other octahedral cation rearrangement was observed. The intensity of the 750 cm−1 band, assigned to translational vibrations of external OH groups in a kaolinitic environment, was quantified and modeled in relation to kaolinite layer proportion. The chemical data show that there are residual interlayer cations in kaolinite domains, which, in accordance with the model mentioned above, disturb external OH-translation vibrations. These results indicate the persistence of certain chemical and structural smectite features in kaolinite domains and thus support a smectite kaolinization process via a solid-state transformation. This confirms previous XRD, thermal, chemical and NMR analyses of the same sample set.
Properties of surface-modified colloidal particles
Authors: Breiner Joan M. , Anderson Michael A. , Tom Harry W. K. , Graham Robert C. 
Published: February 2006

AbstractThe reactivity of colloidal particles is regulated by their surface properties. These properties affect the wettability, flocculation-dispersion characteristics, ion exchange, sorption capacities and transport of inorganic colloids. Most studies have focused on hydrophilic, charged-particle surfaces, often ignoring the alterations in surface properties produced by the adsorption of natural organic matter, surfactants and other compounds. Adsorption of these substances can potentially render a surface substantially more hydrophobic. Nevertheless, comparatively little is known about changes in surface properties and reactivity of minerals upon sorption of hydrophobic organic compounds. In this study, the properties of four minerals (kaolinite, pyrophyllite, montmorillonite and Min-U-Sil®) and two inorganic materials (X-ray amorphous Al hydroxide and X-ray amorphous Si oxide) were compared before and after treatment with the common silylating agent, trimethylchlorosilane (TMCS). The samples were characterized by measurements of total carbon, cation exchange capacity (CEC), particle size, specific surface area (SSA), electrophoretic mobility, contact angle, particle aggregation, and by X-ray diffraction and diffuse reflectance infrared spectroscopy. For the layer silicates, surface coverage was limited to ∼2% trimethyl silane (TMSi). TMSi covered 7.5% of the Min-U-Sil® surface and 33% of the X-ray amorphous Si oxide. Treatment did not affect the structure of the minerals but reduced the CEC, SSA and electrophoretic mobilities. Water contact angles increased to between 18 and 114° with treatment. While the apolar characteristic of the surfaces decreased minimally with treatment, the Lewis acid/base properties were substantially reduced and interfacial free energy shifted from positive to negative values indicating a more hydrophobic surface character. For all the samples except kaolinite, these changes affected the stability of the colloids in suspension depending upon solution pH. Although the grafting of TMSi altered colloidal mineral surface properties and increased their hydrophobicity, these changes were not sufficient to predict colloid aggregation behavior.
Use of atomic force microscopy for examining wet clay
Authors: Selvam Arunkumar , See Chun Hwa , Barkdoll Brian , Prasad Shyam , O’Haver John 
Published: February 2006

AbstractClays and their composites have been widely used for secondary containment walls for underground storage tanks and landfills. The pore-size changes occurring in the clay have a profound effect on its permeability. This study presents a new method for evaluating the use of an atomic force microscope (AFM) for studying wet clay in a non-aqueous state in order to determine the pore-size of clay at various water contents, a type of study typically performed by the more expensive environmental scanning electronic microscope. The method consists of mounting a sponge saturated with water under the sample in order to prevent drying by the heat generated by the AFM electronics. The micro-scale AFM image results show that the clay-particle separations reduce linearly as the water content increases. This change in pore-size is postulated to be attributed to the reduction in the size of the diffuse double layer and more extensive hydrogen bonds between clay particles and bipolar water molecules. The AFM was not able to produce nano-scale images due to excessive adhesion between the cantilever arm and the wet clay sample.
Effect of pH on the rheological behavior of pure and interstratified smectite clays
Authors: Laribi Saoussen , Fleureau Jean-Marie , Grossiord Jean-Louis , Kbir-Ariguib Nejia 
Published: February 2006

AbstractThe effects of pH and ionic strength on the rheological behavior of aqueous suspensions of both crude and purified Wyoming bentonite and natural interstratified illite-smectite from Tunisia were investigated. Flow tests were performed on the four clay suspensions at a 10% clay concentration at different pH values. They showed that the rheological properties were highly sensitive to pH and the nature of the clay. The evolution of the yield stress as a function of pH is characterized by the presence of maxima and minima attributed to changes in the mode of association of the particles. The effect of pH on the behavior of clay suspended in NaCl solutions was also studied. The results show that the presence of NaCl has very little effect on the pH and yield stress values of the four materials.
Smectite-catalyzed dehydration of glucose
Authors: Gonzalez Javier M. , Laird David A. 
Published: February 2006

AbstractThe objective of this study was to determine whether smectites abiotically catalyze transformation of glucose under conditions relevant to soil organic matter (SOM) formation. Four smectites saturated with Na, Ca, Fe and Al were incubated under abiotic conditions with glucose solutions for 21 days at 37°C. After the incubations, soluble organic C recoveries ranged from 95 to 109.3%, relative to the amount of C added as glucose; however, glucose recoveries in the solutions ranged from 18.3 to 98.3%. The results indicate that a significant amount of the added glucose was abiotically transformed to soluble organic compounds other than glucose during the incubations. In general, glucose recoveries decreased with the acidic character of smectites: SWa-1 > Panther > Otay. Also, within clays, glucose recoveries decreased as the exchangeable cation became more acidic: Na > Ca > Al. Higher glucose recoveries were obtained for ‘Fe-rich’ smectites relative to ‘Fe-poor’ smectites, suggesting that Fe-oxyhydroxy coatings on smectite surfaces inhibit the transformation of glucose. High-pressure liquid chromatography analysis of the incubation solutions revealed small peaks for 5-(hydroxymethyl)-2-furaldehyde along with peaks for other unknown compounds. The results suggest that under conditions similar to those found in soils, smectites catalyze glucose dehydration to form furfural compounds. Polymerization of furfural compounds may be a major pathway leading to the formation of new humic materials in soils.
Encapsulation of Co phthalocyanine in alumina-pillared clays and their characterization
Authors: Jagtap Neelam , Ramaswamy Veda 
Published: February 2006

AbstractAlumina-pillared montmorillonite clays (Al-PILC), prepared under ultrasonic (US) agitation and normal stirring (S) methods, have been used as a host material to encapsulate Co phthalocyanine (CoPc) complex. The amount of Co varies from 0.27 to 1.48 wt.% in the samples, depending on the input concentration of Co. Powder X-ray diffraction and other characterization techniques reveal that the structure of Al-PILC remains intact after the incorporation of the complex into the pores through a pyridine solution of the complex by ultrasonic agitation. A substantial decrease in the BET surface area and total pore volume of Al-PILC points to the occupation of the CoPc moieties within the porous structure of the pillared clay. This is further supported by the observation of a band at 1489 cm−1 in the Fourier transform infrared (FTIR) spectra of the encapsulated samples. The FTIR and diffuse reflectance ultraviolet-visible (DRUV-Vis) spectral results indicate that the encapsulated CoPc complex in the clay matrix undergoes distortion in order to accommodate itself within the pores of the Al-PILC. The encapsulated samples prepared by ultrasonification show better dispersion of the complex than the samples prepared under normal stirring conditions. Compared to the ‘neat’ complex, the encapsulated samples (CoPc in Al-PILC) exhibit greater turnover in the test reaction of the oxidation of benzyl alcohol to benzaldehyde with tertbutyl hydroperoxide as the oxidant at 373 K. The method of preparation and consequent site isolation of CoPc in Al-PILC influence the catalytic activity.
Baseline studies of the clay minerals society source clays: Specific surface area by the Brunauer Emmett Teller (BET) method
Authors: Dogan A. Umran , Dogan Meral , Onal Muserref , Sarikaya Yuksel , Aburub Aktham , Wurster Dale Eric 
Published: February 2006

AbstractSpecific surface area measurements of The Clay Minerals Society source clays were made by the Brunauer, Emmett and Teller (BET) method of adsorption of nitrogen gas. Two replicate measurements of specific surface area were performed for each source clay. All pair values were within 3%, which is very good agreement for this type of measurement.
Microbial reduction of Fe(III) in the Fithian and Muloorina illites: Contrasting extents and rates of bioreduction
Authors: Seabaugh Jennifer L. , Dong Hailiang , Kukkadapu Ravi K. , Eberl Dennis D. , Morton John P. , Kim Jinwook 
Published: February 2006

AbstractShewanella putrefaciens CN32 reduces Fe(III) within two illites which have different properties: the Fithian bulk fraction and the <0.2 µm fraction of Muloorina. The Fithian illite contained 4.6% (w/w) total Fe, 81% of which was Fe(III). It was dominated by illite with some jarosite (∼32% of the total Fe(III)) and goethite (11% of the total Fe(III)). The Muloorina illite was pure and contained 9.2% Fe, 93% of which was Fe(III). Illite suspensions were buffered at pH 7 and were inoculated with CN32 cells with lactate as the electron donor. Select treatments included anthraquinone-2,6-disulfonate (AQDS) as an electron shuttle. Bioproduction of Fe(II) was determined by ferrozine analysis. The unreduced and bioreduced solids were characterized by Mössbauer spectroscopy, X-ray diffraction and transmission electron microscopy. The extent of Fe(III) reduction in the bulk Fithian illite was enhanced by the presence of AQDS (73%) with complete reduction of jarosite and goethite and partial reduction of illite. Mössbauer spectroscopy and chemical extraction determined that 21–25% of illite-associated Fe(III) was bioreduced. The extent of bioreduction was less in the absence of AQDS (63%) and only jarosite was completely reduced with partial reduction of goethite and illite. The XRD and TEM data revealed no significant illite dissolution or biogenic minerals, suggesting that illite was reduced in the solid state and biogenic Fe(II) from jarosite and goethite was either released to aqueous solution or adsorbed onto residual solid surfaces. In contrast, only 1% of the structural Fe(III) in Muloorina illite was bioreduced. The difference in the extent and rate of bioreduction between the two illites was probably due to the difference in layer charge and the total structural Fe content between the Fithian illite (0.56 per formula) and Muloorina illite (0.87). There may be other factors contributing to the observed differences, such as expandability, surface area and the arrangements of Fe in the octahedral sheets. The results of this study have important implications for predicting microbe-induced physical and chemical changes of clay minerals in soils and sediments.
Hydrothermal synthesis of smectite from dickite
Authors: Ryu Kyoung-Won , Jang Young-Nam , Chae Soo-Chun , Bae In-Kook , Choi Sang-Hoon 
Published: February 2006

AbstractDioctahedral smectite was prepared hydrothermally from dickite [Al2Si2O5(OH)4] as a starting material by autoclaving in a closed stainless steel vessel with variable temperature, pressure, time and pH conditions. Highly crystalline smectite can be obtained at 290°C under a pressure of 69 bar for 48 h. The pH of the solution was an important factor and should be maintained at 10 to 11 for the successful formation of smectite. Characterization by X-ray powder diffraction, scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, differential thermal analysis and the Greene-Kelly test showed that the smectite synthesized was Na-beidellite, mostly because of the heat treatment of the starting material and the stoichiometric batch composition.