bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in clay organization due to structural iron reduction in a flooded vertisol
Authors: Favre F. , Jaunet A. M. , Pernes M. , Badraoui M. , Boivin P. , Tessier D. 
Published: August 2004

AbstractThe purpose of this study was to investigate the impact of redox-induced changes in the organization of the clay fraction of a bulk vertisol using transmission electron microscopy. Chemical and X-ray powder diffraction (XRD) analyses indicated that the oxidized clay was composed of 32% kaolinite and 68% non-pure smectitic material, mostly a dioctahedral beidellite with octahedral Fe, according to Quantarg2 and DecompXR models.The cation exchange capacity of the soil increased from 26.1 to 65 cmolc+kg-1due to structural iron (FeStr) reduction and dissolution of oxide coatings. Transmission electron micrographs revealed dramatic changes upon reduction. Oxides were dissolved and the smectite increased in particle darkness, lateral extension, thickness, compactness and stacking order. These changes were interpreted to be a consequence of sorption of ferrous Fe and reduction of FeStr, as found in previous studies on pure Fe-bearing smectites.
Influence of grinding on the structure and colour properties of talc, bentonite and calcite white fillers
Authors: Christidis G. E. , Makri P. , Perdikatsis V. 
Published: August 2004

AbstractThe influence of grinding on colour and particle-size properties of talc and smectite from a white bentonite were studied and compared with a fine-grained calcite from a chalk. Grinding decreased the grain size of all three minerals. The crystallite size and structure of smectite was not affected but the crystallite size of talc decreased. The Si–O–Mg and Mg–O bonds of talc were disrupted and cation exchange capacity increased with increasing grinding. Delamination of talc crystallites was observed in the initial stages of grinding, whereas with more intense treatment, amorphous material was formed. Comminution improved the colour properties of all three minerals, namely brightness, L* (lightness) and ΔE*ab (deviation from perfect white diffuser). Grinding time exerts greater influence on the reflectance from calcite surfaces than from clay minerals. This difference is attributed to continuous formation of progressively smaller diffuse reflection units forming a smoother calcite surface. Decrease of grain size does not form considerably smaller diffuse reflection units in clay minerals unless delamination takes place. With prolonged grinding, amorphization forms additional diffuse reflection units and a smoother surface due to comminution.
Thermal evolution of Mg-Al-CO3 hydrotalcites
Authors: Stanimirova Ts. , Piperov N. , Petrova N. , Kirov G. 
Published: August 2004

AbstractThe thermal decomposition of hydrotalcite (HT), with chemical composition Mg1-xAlx(OH)2(CO3)x/2.(1-3x/2)H2O, (0.20 < x ≤ 0.33), is a complex sequence of dehydration, dehydroxylation and decarbonization and leads to the formation of a series of metaphases: HT-D (dehydrated HT), HT-B (partially dehydroxylated HT) and MO (mixed oxides with periclase-like structure). The evolution of water and CO2 in natural and synthetic hydrotalcites (a Mg/Al ratio between 2:1and 3.7:1), heated to 800°C, was investigated by differential thermal analysis, thermogravimetry and evolved gas analysis. At least six endothermic and two exothermic effects were established by computer-aided resolving of the curves. The formation of each HT metaphase was related to the release of a discrete number of water molecules depending on the Al content in the samples and each appeared as a corresponding endothermic peak in the DTA curves. The exothermic processes associated with the crystallization of HT-B and MO metaphases were specified by decomposition of DTA curves. The evolution of CO2 during the thermal decomposition of the carbonate groups was found to be different for the samples studied. The preservation of CO3 even at high temperatures was established for synthetic samples with a high Al content. The release of volatile H2O and CO2 (which comprise ~40% of the sample mass) provokes fine cracking both along and across the layers.
Factors influencing the intercalation degree (‘reactivity’) of kaolin minerals with potassium acetate, formamide, dimethylsulphoxide and hydrazine
Authors: Franco F. , Ruiz Cruz M. D. 
Published: August 2004

AbstractFactors influencing the degree of intercalation (‘reactivity’) of kaolinite group minerals have been investigated using six kaolin minerals, with variable crystallinity and particle size. Tests were performed to measure the degree of intercalation with potassium acetate, formamide, dimethylsulphoxide and hydrazine.These experiments indicate that intercalation degree depends on a number of factors, including particle size, degree of ordering, type of guest molecules, method of intercalation, and presence and types of impurities. Anew method for determination of the degree of intercalation is proposed, which is not dependent on the intensity of complex reflections. The results indicate that formamide is the most sensitive reagent to distinguish differently ordered kaolin minerals whereas hydrazine appears as the most appropriate reagent to differentiate kaolin minerals from other 7 Å phases.
Authigenic halloysite from El-Gideda iron ore, Bahria Oasis, Egypt: characterization and origin
Authors: Baioumy H. M. , Hassan M. S. 
Published: August 2004

AbstractHalloysite in El-Gideda iron mine occurs as very soft, light and white-to-pinkish white pockets and lenses ranging in diameter from 50 cm to 1 m within the iron ore. Highly hydrated halloysite is the main constituent of these pockets beside some kaolinite and alunite. The diffraction pattern of the clay fraction (<2 mm) shows a rather broad and diffuse 001 reflection spread between 10.3 and 13.6°2θ. Upon treatment, the 001 reflection of halloysite expands up to 10.94 Å and 11.9 Å corresponding to ethylene glycol and dimethyl formamide treatment, respectively. After these treatments, kaolinite appeared with its characteristic basal spacing (~7 Å). The percentage of halloysite in halloysite-intercalated kaolinite ranged between 80 and 90%. Heating to 350°C, produces a kaolinite-like structure (~7.1 Å) that developed to a metakaolinite-structure when heated to 550°C. Morphologically, halloysite appears as well developed tubes composed entirely of SiO2 and Al2O3, while kaolinite is characterized by very fine platelets arranged in book-like or rosette-like shapes. A differential thermal analysis curve of the studied halloysite showed an endothermic peak at ~138°C due to the dehydration of interlayer water of halloysite. The small shoulder at ~540°C and the endothermic peak at ~593°C is attributed to the dehydroxylation of halloysite, kaolinite and alunite. On the other hand the exothermic peak that appeared at 995°C is due to the formation of new phases such as mullite and/or spinel. The infrared vibrational spectrum is typical of highly disordered halloysite and kaolinite.Halloysite was formed as a result of alteration of the overlying glauconite suggesting intensive chemical alteration during a humid wet period that prevailed in the Bahria Oasis during the late Eocene. Glauconite alteration releases K, Fe, silica and alumina. Iron forms at least part of the iron ore in the El-Gideda mine while alumina forms halloysite as well as alunite when interacted with silica in an acidic environment.
Origin of the Basoren (Kutahya, W Turkey) bentonite deposits
Authors: Yildiz A. , Kuscu M. 
Published: August 2004

AbstractBentonite deposits in Basoren Kutahya, West Anatolia, Turkey formed from alteration of perlite and pyroclastic rocks of Pliocene age. The distribution of bentonite deposits along faults in the study area indicates that the alteration solutions were hydrothermal. Although lateral zonation is observed in bentonite deposits in some regions (i.e. Demirli, Akyokus, Seklice- Sarıokuz, etc.), alteration zones are extremely irregular in the Cayırlık bentonite deposit.X-ray diffraction studies have shown that Basoren bentonites contain dioctahedral Ca-smectite.The Greene-Kelly test (Li-saturation and heating) showed that the Demirli and Akyokus bentonites consist of montmorillonite and that the Cayırlık bentonite consists of montmorillonite and/or beidellite. Spherulitic or hemispherical ‘crystals’ of opal-CT minerals formed from hydrothermal alteration of volcanic glass. The MgO, CaO and total Fe2O3 enrichment in bentonites, compared to parent rocks, is related to the chemical composition of hydrothermal solutions that passed through the ophiolitic rocks such as serpentinite.
Hematopoietic stem cell transplantation does not restore dystrophin expression in Duchenne muscular dystrophy dogs
Authors: Dell'Agnola Chiara , Wang Zejing , Storb Rainer , Tapscott Stephen J. , Kuhr Christian S. , Hauschka Stephen D. , Lee Richard S. , Sale George E. , Zellmer Eustacia , Gisburne Serina , Bogan Janet , Kornegay Joe N. , Cooper Barry J. , Gooley Theodore A. , Little Marie-Térèse 
Published: August 2004

Abstract
Duchenne muscular dystrophy (DMD) is caused by mutations in the dystrophin gene on the X-chromosome that result in skeletal and cardiac muscle damage and premature death. Studies in mice, including the mdx mouse model of DMD, have demonstrated that circulating bone marrow–derived cells can participate in skeletal muscle regeneration, but the potential clinical utility of treating human DMD by allogeneic marrow transplantation from a healthy donor remains unknown. To assess whether allogeneic hematopoietic cell transplantation (HCT) provides clinically relevant levels of donor muscle cell contribution in dogs with canine X-linked muscular dystrophy (c-xmd), 7 xmd dogs were given hematopoietic cell (HC) transplants from nonaffected littermates. Compared with the pretransplantation baseline, the number of dystrophin-positive fibers and the amount of wild-type dystrophin RNA did not increase after HCT, with observation periods ranging from 28 to 417 days. Similar results were obtained when the recipient dogs were given granulocyte colony-stimulating factor (G-CSF) after their initial transplantation to mobilize the cells. Despite successful allogeneic HCT and a permissive environment for donor muscle engraftment, there was no detectable contribution of bone marrow–derived cells to either skeletal muscle or muscle precursor cells assayed by clonal analyses at a level of sensitivity that should detect as little as 0.1% donor contribution.
Early tracheostomy in intensive care trauma patients improves resource utilization: a cohort study and literature review
Authors: Arabi Yaseen , Haddad Samir , Shirawi Nehad , Al Shimemeri Abdullah 
Published: August 2004

Abstract
Introduction
Despite the integral role played by tracheostomy in the management of trauma patients admitted to intensive care units (ICUs), its timing remains subject to considerable practice variation. The purpose of this study is to examine the impact of early tracheostomy on the duration of mechanical ventilation, ICU length of stay, and outcomes in trauma ICU patients.

Methods
The following data were obtained from a prospective ICU database containing information on all trauma patients who received tracheostomy over a 5-year period: demographics, Acute Physiology and Chronic Health Evaluation II score, Simplified Acute Physiology Score II, Glasgow Coma Scale score, Injury Severity Score, type of injuries, ICU and hospital outcomes, ICU and hospital length of stay (LOS), and the type of tracheostomy procedure (percutaneous versus surgical). Tracheostomy was considered early if it was performed by day 7 of mechanical ventilation. We compared the duration of mechanical ventilation, ICU LOS and outcome between early and late tracheostomy patients. Multivariate analysis was performed to assess the impact of tracheostomy timing on ICU stay.

Results
Of 653 trauma ICU patients, 136 (21%) required tracheostomies, 29 of whom were early and 107 were late. Age, sex, Acute Physiology and Chronic Health Evaluation II score, Simplified Acute Physiology Score II and Injury Severity Score were not different between the two groups. Patients with early tracheostomy were more likely to have maxillofacial injuries and to have lower Glasgow Coma Scale score. Duration of mechanical ventilation was significantly shorter with early tracheostomy (mean ± standard error: 9.6 ± 1.2 days versus 18.7 ± 1.3 days; P < 0.0001). Similarly, ICU LOS was significantly shorter (10.9 ± 1.2 days versus 21.0 ± 1.3 days; P < 0.0001). Following tracheostomy, patients were discharged from the ICU after comparable periods in both groups (4.9 ± 1.2 days versus 4.9 ± 1.1 days; not significant). ICU and hospital mortality rates were similar. Using multivariate analysis, late tracheostomy was an independent predictor of prolonged ICU stay (>14 days).

Conclusion
Early tracheostomy in trauma ICU patients is associated with shorter duration of mechanical ventilation and ICU LOS, without affecting ICU or hospital outcome. Adopting a standardized strategy of early tracheostomy in appropriately selected patients may help in reducing unnecessary resource utilization.
The phosphatidylserine receptor has essential functions during embryogenesis but not in apoptotic cell removal
Authors: Böse Jens , Gruber Achim D , Helming Laura , Schiebe Stefanie , Wegener Ivonne , Hafner Martin , Beales Marianne , Köntgen Frank , Lengeling Andreas 
Published: August 2004

Abstract
Background
Phagocytosis of apoptotic cells is fundamental to animal development, immune function and cellular homeostasis. The phosphatidylserine receptor (Ptdsr) on phagocytes has been implicated in the recognition and engulfment of apoptotic cells and in anti-inflammatory signaling. To determine the biological function of the phosphatidylserine receptor in vivo, we inactivated the Ptdsr gene in the mouse.

Results
Ablation of Ptdsr function in mice causes perinatal lethality, growth retardation and a delay in terminal differentiation of the kidney, intestine, liver and lungs during embryogenesis. Moreover, eye development can be severely disturbed, ranging from defects in retinal differentiation to complete unilateral or bilateral absence of eyes. Ptdsr-/- mice with anophthalmia develop novel lesions, with induction of ectopic retinal-pigmented epithelium in nasal cavities. A comprehensive investigation of apoptotic cell clearance in vivo and in vitro demonstrated that engulfment of apoptotic cells was normal in Ptdsr knockout mice, but Ptdsr-deficient macrophages were impaired in pro- and anti-inflammatory cytokine signaling after stimulation with apoptotic cells or with lipopolysaccharide.

Conclusion
Ptdsr is essential for the development and differentiation of multiple organs during embryogenesis but not for apoptotic cell removal. Ptdsr may thus have a novel, unexpected developmental function as an important differentiation-promoting gene. Moreover, Ptdsr is not required for apoptotic cell clearance by macrophages but seems to be necessary for the regulation of macrophage cytokine responses. These results clearly contradict the current view that the phosphatidylserine receptor primarily functions in apoptotic cell clearance.
Role of Adjuvant Chemotherapy in Patients With Resected Non–Small-Cell Lung Cancer: Reappraisal With a Meta-Analysis of Randomized Controlled Trials
Authors: Hotta Katsuyuki , Matsuo Keitaro , Ueoka Hiroshi , Kiura Katsuyuki , Tabata Masahiro , Tanimoto Mitsune 
Published: August 2004

Purpose The role of adjuvant chemotherapy in patients with resected non–small-cell lung cancer (NSCLC) remains to be defined. This study was aimed at re-evaluating the effectiveness of adjuvant chemotherapy in patients with resected NSCLC, by performing a meta-analysis of relevant trials. Methods We performed a literature search to identify trials reported after the publication of a meta-analysis in 1995, comparing patients with NSCLC receiving chemotherapy after surgery with those undergoing surgery alone. The hazard ratio (HR) was estimated to assess the survival advantage of adjuvant chemotherapy. Results Eleven trials conducted on a total of 5,716 patients were identified by the literature search. In these trials, hazard ratio estimates suggested that adjuvant chemotherapy yielded a survival advantage over surgery alone (HR, 0.872; 95% CI, 0.805 to 0.944; P = .001). In a subset analysis, both cisplatin-based chemotherapy (HR, 0.891; 95% CI, 0.815 to 0.975; P = .012) and single-agent therapy with tegafur and uracil (UFT; HR, 0.799; 95% CI, 0.668 to 0.957; P = .015) were found to yield a significant survival benefit. The toxicities of adjuvant chemotherapy were found to be generally mild. Conclusion This is the first updated meta-analysis demonstrating the importance of cisplatin-based chemotherapy and single-agent UFT therapy as adjuvant chemotherapy in the treatment of resected NSCLC. Although the results must be carefully interpreted because of one limitation (the meta-analysis was performed with abstracted data), they raise critical issues that must be resolved in future studies.
Are we managing deep venous thrombosis of the upper limb appropriately?
Authors: Fassiadis N , Pepas L , Chan M , Mason D , Morgan M 
Published: August 2004

Objective: The objective of this retrospective study was to analyse risk factors, management and outcome of upper limb deep venous thrombosis (ULDVT) in two London district hospitals. Methods: The study group audited between May 1995 and July 2002 comprised 33 patients with ULDVTs, of which 12 were primary and 21 were secondary. Results: Common risk factors included malignant disease ( n=17, 51.5%), smoking ( n=16, 48.5%), central venous access ( n=9, 27.3%), cardiac disease ( n =6, 18.2%) and hormonal therapy ( n=4, 12.1%). None of the patients were evaluated for thoracic outlet compression. A thrombophilia screen was performed in eight patients with primary ULDVT and in seven patients with secondary ULDVT. Thrombophilic states were identified only in the primary group, in two patients. Twenty-eight patients were anticoagulated (84.8%) and overall symptoms resolved in 20 patients (60.6%). All 13 deaths occurred within the secondary group. Conclusions: The present study reveals that there is no consensus in investigating and managing patients with ULDVT, which is probably due to the variety of aetiological factors of this condition.
Venoruton metabolites: pharmacological activity and kinetics
Authors: Hasler-Nguyen N , Shelton D , Ponard G , Zijlstra J 
Published: August 2004

Objective: This study was undertaken to further elucidate the mechanism of action of the phlebotonic drug Venoruton®, which is a standardized mixture of hydroxyethylrutosides (HR). Methods: First, its oral absorption in rats was compared with that of hydroxyethylquercetins (HQ), which are the hydrolysed aglycones of HR. Second, the pharmacological activity of the major HR metabolites in humans, mono-3′-hydroxyethylquercetin (mono-3′HQ) and a mixture with mono-4′HQ, were further evaluated in vitro. Results: Time to reach the maximal plasma concentration of its marker metabolite mono-4′HQ was significantly shorter after HQ than after HR administration, with an eightfold higher maximal concentration. The rapid absorption of HQ and the increased plasma levels confirm the theory that rutosides need to be hydrolysed by the intestinal microflora prior to absorption. Mono-3′HQ and, even more so, the mixture with mono-4′HQ inhibited xanthine oxidase, an enzyme responsible for the formation of reactive oxygen species, at concentrations comparable to those found in human plasma. The metabolites also inhibited the formation of superoxide radicals induced by the respiratory burst of activated HL-60 neutrophils. Both HR metabolites decreased the degree of cell death of human umbilical vein endothelial cells that were exposed to hypoxia/reoxygenation conditions, probably by scavenging destructive superoxide radicals. Conclusions: These results demonstrated new pharmacological activities, which contribute to the understanding of the mechanisms of action of HR in chronic venous insufficiency.
Surgical treatments for chronic deep venous insufficiency
Authors: Scott N A , Corabian P , Forbes T L , Hardy S C 
Published: August 2004

Objective: The aim of this study was to critically appraise and synthesize the published evidence regarding the short- and long-term efficacy/effectiveness of surgical techniques for patients with deep venous insufficiency (DVI) refractory to other forms of management. Methods: All original, published studies on non-pregnant human patients undergoing treatment for deep or mixed deep/superficial/perforator chronic venous insufficiency were identified by systematically searching PubMed, EMBASE, CINAHL, The Cochrane Library, Science Citation Index and the websites of various health technology assessment agencies, research registers and guidelines sites, from January 1990 to July 2003. No language restriction was applied. Results: A total of two randomized controlled trials and 12 non-randomized comparative studies reported on a variety of procedures ranging from superficial venous surgery (SVS) and subfascial endoscopic perforator surgery (SEPS), through to deep venous reconstruction (including valvuloplasty, transplantation and transposition) for the treatment of DVI. Limited evidence suggested that combined SVS/valvuloplasty is a relatively safe procedure that is potentially more effective than SVS alone in preventing ulcer recurrence in patients with primary DVI in both the short- and mid-term. Evidence for the efficacy of valvuloplasty, bypass, transplantation, SEPS and iliac stenting in the treatment of DVI was inconclusive. The optimal surgery for patients with deep venous obstruction or secondary valvular incompetence remains unclear. Conclusions: It is unlikely that a large randomized, or even non-randomized, controlled trial will be conducted to ascertain the safety and efficacy of surgery for DVI. However, standardized reporting and collection of data in a registry would be a move forward. In addition, professional bodies should consider providing guidance, in the form of an evidence-based treatment algorithm, that would define when to perform SVS in patients with mixed or deep venous insufficiency and what type of deep venous surgery is considered appropriate for different indications. A prime focus of future research may be to understand why less invasive treatments have failed in patients requiring surgery for DVI and to identify those patients who would benefit most from early surgical intervention.
Effectiveness and safety of calcium dobesilate in treating chronic venous insufficiency: randomized, double-blind, placebo-controlled trial
Authors: Labs K-H , Degischer S , Gamba G , Jaeger K A 
Published: August 2004

Objective: To determine whether calcium dobesilate is effective in reducing chronic venous insufficiency-related peripheral oedema. Methods: Randomized, double-blind, placebo-controlled, multicentre, parallel-group study in 253 consecutive outpatients with chronic venous insufficiency (CEAP C3-C4). The patients were treated for four weeks with either calcium dobesilate (CaD) 500 mg three times a day or matching placebo. The primary outcome measure was the reduction in lower leg volume. The leg volume calculation was based on a truncated cone model Results: Active drug treatment resulted in a median reduction of the leg volume of 25.5 ± 33.6 ml/l tissue. The difference in the median change of the leg volume between the treatment groups at week 4 was -12.2 ml/l tissue (95 % CI -21.6 to -2.8; P =0.01). In contrast with the placebo, the effects of CaD were independent of the duration of CVI and most pronounced in more severely diseased patients. Safety variables did not differ significantly between groups. Conclusions: Calcium dobesilate is an effective and well tolerated treatment for chronic venous insufficiency.