bluuebunny/crossref_metadata_2025_split huggingface dataset:
A systematic investigation on the influence of the chemical treatment of natural fibers on the properties of their polymer matrix composites
Authors: Biagiotti Jerico , Puglia Debora , Torre Luigi , Kenny José M. , Arbelaiz Aitor , Cantero Guillermo , Marieta Cristina , Llano‐Ponte Rodrigo , Mondragon Iñaki 
Published: October 2004

AbstractThis paper reports a systematic study of the effects on composite properties of different chemical treatments on natural fibers. Both short flax fibers and flax cellulose pulp in a polypropylene matrix have been investigated. The influence of treatments on fiber properties was investigated by means of spectroscopic, thermal and mechanical tests. Moreover, the effects of fiber treatment on the crystallinity of the matrix were analyzed using differential scanning calorimetry and optical microscopy. The mechanical properties of the composites obtained were studied using tensile and bending tests. It is shown that most of the main properties of the composites can be improved by adequately treating the fibers. The results of this study provide a database mainly devoted to material selection for the automotive industry. This research has been performed as a part of the ECOFINA project in the framework of the 5th European Research Program of the European Community. Polym. Compos. 25:470–479, 2004. © 2004 Society of Plastics Engineers.
The impact response of aluminum foam sandwich structures based on a glass fiber‐reinforced polypropylene fiber‐metal laminate
Authors: Kiratisaevee H. , Cantwell W. J. 
Published: October 2004

AbstractThe fracture properties and impact response of a series of aluminum foam sandwich structures with the glass fiber–reinforced polypropylene‐based fiber‐metal laminate (FML) skins have been studied. Initially, the manufacturing process for producing the FML skins was optimized to obtain a strong bond between the composite plies and the aluminum layers. The degree of adhesion between the composite plies and the aluminum was characterized by conducting single cantilever beam tests. Here, it was found that the composites could be successfully bonded to the aluminum using a simple short stamping procedure. A detailed examination of the fracture surfaces indicated that crack propagation occurred within the composite ply in the fiber‐metal laminates and along the composite‐aluminum foam interface in the sandwich structures. The low velocity impact response of the FMLs and the sandwich structures was investigated using an instrumented drop‐weight impact tower and a laser‐Doppler velocimeter. The energy absorption characteristics of the sandwich structures were investigated along with the failure processes. Finally, a series of tensile tests on the damaged FMLs and thermoplastic sandwich structures showed that both systems offer promising residual load‐bearing properties. Here, shear failure in the aluminum foam was observed in the sandwich structures, indicative of a strong bond between the FML skins and the aluminum core. Polym. Compos. 25:499–509, 2004. © 2004 Society of Plastics Engineers.
Differential expression of proteins in rat plasma exposed to benzene
Authors: Lee Hyun‐Ju , Lee Do‐Youn , Joo Won‐A , Sul Donggeun , Lee Eunil , Kim Chan‐Wha 
Published: October 2004

AbstractBenzene, a ubiquitous environmental contaminant, is an important solvent in the chemical industry and is also known as a constituent of petroleum. It has been reported that benzene is associated with hematotoxicity including leukemia in humans and cancer in laboratory animals. To study protein expression alterations in rat plasma exposed to benzene, rats were exposed to levels of 1, 10, 100 ppm benzine for 6 h/day and 5 d/week for 2 or 6 weeks. Two‐dimensional gel electrophoresis of rat plasma was carried out, and approximately 1000 protein spots were detected on the gels. The 11 spots which showed significantly different expression were selected and identified with matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry. Analyzing the targeted 11 spots, there was no correlation between the 2 and 6 weeks benzene‐inhaled groups on up‐regulated proteins (zinc finger protein, and tristetraprolin) and on down‐regulated proteins (cAMP‐regulated guanine nucleotide exchange factor II, protein kinase and unknown protein). The overexpressed proteins (inhibitor of κB‐like protein, GTP‐binding protein rab14, T‐cell receptor alpha chain, and somatostatin transactivating factor‐1) were detected only in groups inhaling benzene for 6 weeks. Among them the expression level of T‐cell receptor alpha chain was confirmed by Western blot.
Local orbitals for the study of the π→π* excitation in polyenes
Authors: Pitarch‐Ruiz J. , Evangelisti S. , Maynau D. 
Published: October 2004

AbstractLocalized orbitals have recently been employed in large ab initio calculations, but their use has generally been restricted to ground‐state problems. In this work, we analyze the molecular orbitals of the excited states, optimized with a recently proposed local procedure. This method produces local orbitals of the CAS–SCF type, which permits its application to the study of excited states. In particular, we focus on the π→π* triplet excited state in polyenes, calculated using a 2/2 CAS space which includes two electrons in one π and one π* orbitals. In small polyenes, these two singly occupied active orbitals are delocalized all along the molecule. The extent of the delocalization is analyzed by studying polyenes of increasing size. Different polyenes have been studied, going from C14H16 to the C70H72 polyene. The relation of the π→π* excitation with the cation and anion systems is also discussed. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Use of C60 cluster projectiles for sputter depth profiling of polycrystalline metals
Authors: Sun S. , Szakal C. , Roll T. , Mazarov P. , Wucher A. , Winograd N. 
Published: October 2004

AbstractWe have investigated the merits of fullerene cluster ions as projectiles in time‐of‐flight secondary neutral mass spectrometry (ToF‐SNMS) sputter depth profiling of an Ni:Cr multilayer sample similar to the corresponding NIST depth profiling standard. It is shown that sputter erosion under bombardment with C60+ ions of kinetic energies between 10 and 20 keV provides good depth resolution corresponding to interface widths of several nanometres. This depth resolution is maintained during the complete removal of the multilayer stack with a total thickness of 500 nm. This finding is in contrast to the case where atomic Ga+ projectile ions of comparable kinetic energy are used, demonstrating the unique features of cluster projectiles in sputter depth profiling. Copyright © 2004 John Wiley & Sons, Ltd.
Error estimation in peak‐shape analysis of XPS core‐level spectra using UNIFIT 2003: how significant are the results of peak fits?
Authors: Hesse R. , Chassé T. , Streubel P. , Szargan R. 
Published: October 2004

AbstractAn error analysis for numerically evaluating random uncertainties in x‐ray photoelectron spectroscopy has been implemented in version 2003 of the spectra treatment and analysis software UNIFIT in order to improve the understanding of the statistical basis and the reliability of the model parameters for photoelectron spectra. The theoretical basis as well as two approaches to obtain error limits of the fit parameters have been considered. Several test spectra have been analysed and discussed. A representative example has been chosen to demonstrate the relevance of the error estimation for practical surface analysis. Suggestions for the minimization of errors in the peak‐fitting procedures are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Variation of the electron inelastic mean free path during depth profiling of the Fe/Si interface as determined by quantitative REELS
Authors: Prieto P. , Hofmann S. , Elizalde E. , Sanz J. M. 
Published: October 2004

AbstractThe aim of this work is to determine the dependence of the electron inelastic mean free path (IMFP) at the Fe/Si interface during depth profiling by sputtering with 3 keV Ar+ ions. In order to estimate the variation of the IMFP at the interface, reflection electron energy‐loss spectroscopy (REELS) measurements were performed after different sputtering times at the Fe/Si interface with three different primary electron energies (i.e. 0.5, 1 and 1.5 keV). Even though it is highly likely that a compound (i.e. FexSi) is formed at the interface, all the experimental REELS spectra could be analysed as a linear combination of those corresponding to pure Si and Fe. Using the model developed by Yubero and Tougaard for quantitative analysis of these REELS spectra we could estimate the IMFP values along the depth profile at the interface. The resulting IMFPs are observed to vary linearly with the average composition (as determined by REELS) at the Fe/Si interface as it is sputter depth profiled. The energy dependence of the IMFP for different compositions is presented and discussed. For completeness, we have determined the energy‐loss functions as well as the IMFPs of the pure elements (i.e. Fe and Si). Copyright © 2004 John Wiley & Sons, Ltd.
An XPS study of microporous and mesoporous titanosilicates
Authors: Moretti G. , Salvi A. M. , Guascito M. R. , Langerame F. 
Published: October 2004

AbstractIn this contribution we report on an XPS study of microporous and mesoporous titanosilicates, in particular microporous titanium silicalite TS‐1, ordered mesoporous Ti‐MCM‐41 and [Ti]‐MCM‐41 and amorphous mesoporous silica–titania (MST) catalysts.Our aim was to obtain both photoemission and x‐ray‐excited Auger data for Ti species on these catalysts and use them in a Ti Wagner plot to rationalize the dependence of the local electronic structure on the atomic environment. Isolated Ti(IV) species coordinated to four and six oxygen anions and segregated TiO2 clusters were detected on all catalysts by a curve‐fitting procedure of Ti 2p, O 1s and related peaks.The presence of the Si 2p peak excited by an O Kα ghost makes the detection of Ti LMM Auger transitions in mesoporous samples impossible due to the low Ti loadings and its homogeneous distribution in the silica matrix. Small TiO2 clusters are eventually segregated within the mesopores of the catalysts and not at their external surface. On TS‐1 microporous catalysts with similar Ti loadings to the mesoporous catalysts we were able to detect Ti LMM Auger transitions, and by the Ti Wagner plot we clearly identify the presence of octahedrally coordinated Ti(IV) species. Thus, it is suggested that on TS‐1 the in‐framework (O)4Ti species are easily changed to (O)4(H2O)2Ti species by insertion of water molecules from the atmosphere. Small TiO2 clusters (diameter <5 nm), eventually present on samples with Ti loading >2 wt.%, are segregated at their external surface and present spectroscopic features similar to (O)4(H2O)2Ti species. Copyright © 2004 John Wiley & Sons, Ltd.
Monte‐Carlo simulation of secondary electron emission by x‐ray irradiation—an application of x‐ray absorption near‐edge structure (XANES)
Authors: Iyasu Takeshi , Tamura Keiji , Shimizu Ryuichi , Zhang Zengming , Koshikawa Takanori , Yoshikawa Hideki , Fukushima Sei 
Published: October 2004

AbstractA Monte‐Carlo simulation program has been developed for describing x‐ray absorption near‐edge structure (XANES) observed by synchrotron radiation. The Monte‐Carlo simulation was applied for interpreting XANES spectroscopy on a polycrystalline Ag specimen under synchrotron irradiation with photon energy 3340–3390 eV around the absorption edge of the Ag Lα line at 3352 eV.The results clearly indicate that Monte‐Carlo simulation describes the experimental results with considerable success. Dependence of secondary electron yield on the incident angle of synchrotron radiation was also studied. Copyright © 2004 John Wiley & Sons, Ltd.
Relation between liver pathology and prognosis in patients with portal hypertension
Authors: Aiden McCormick P. , Burroughs Andrew K. 
Published: October 2004

AbstractThe most common causes of variceal bleeding are cirrhosis, schistosomiasis, and extrahepatic portal venous obstruction. The prognosis for an individual patient depends on the severity of the bleeding episode and the underlying liver function. Liver function is determined to a large extent by the underlying liver pathology. Patients with noncirrhotic portal hypertension or cirrhosis with good liver function have good short‐ and long‐term prognoses. In patients with established cirrhosis, the presence of alcoholic hepatitis, hepatocellular carcinoma, or portal venous thrombosis may adversely affect prognosis. In addition to affecting prognosis, the underlying pathology may also influence choice of treatment. This point is particularly true for treatments such as shunt surgery, liver transplantation, or transjugular intrahepatic shunts.
Surgical management of acute variceal hemorrhage
Authors: Rikkers Layton F. , Jin Gongliang 
Published: October 2004

AbstractThe advent of more effective nonoperative therapies, mainly endoscopic variceal sclerosis, has decreased the need for emergency surgery for control of acute variceal hemorrhage. In centers where it is available, nonoperative portal decompression by transjugular intrahepatic portosystemic shunting (TIPS) is likely to have a further impact. When acute or chronic sclerotherapy fails or when bleeding is secondary to gastric varices or portal hypertensive gastropathy, emergency surgery may be life‐saving and should be done promptly before worsening hepatic functional decompensation develops. Child's class C liver disease is not a contraindication to emergency surgery; many patients who fail nonoperative attempts at control of bleeding are of this risk status. The most commonly utilized emergency procedures are portacaval and interposition mesocaval shunts, both of which are effective, and esophageal transection, which is associated with a higher incidence of late rebleeding. An emergency distal splenorenal shunt is appropriate for selected patients who are not actively bleeding at the time of surgery. TIPS is the preferred alternative for acute or chronic endoscopic sclerotherapy failures who are candidates for liver transplantation within the succeeding 6 to 12 months.
Total shunting and elective management of variceal bleeding
Authors: Stipa Sergio , Balducci Genoveffa , Ziparo Vincenzo , Stipa Francesco , Lucandri Giorgio 
Published: October 2004

AbstractA 20‐year experience with treatment of esophageal varices in patients with cirrhosis is reported. Considering that total shunts are well tolerated iminediately after operation (hospital mortality rate for all elective procedures being 6.4%), that they offer a good protection against rebleeding (rebleeding variceal rate of 7.6%), and that they offer the same long‐term survival as given by other shunts (5‐and 10‐year survival rates of 57% and 31%, respectively), the authors affirm that these kinds of shunts are still useful in well selected cases. Late follow‐up results of a prospective randomized trial of elective mesocaval shunts compared to portacaval shunt have shown no significant differences in operative mortality, reoleeding rates, encephalopathy rates, or survival. Based on this information, the authors currently use portacaval shunt as their operation of choice.
Role of distal splenorenal shunt for long‐term management of variceal bleeding
Authors: Henderson J. Michael 
Published: October 2004

AbstractDistal splenorenal shunt (DSRS) has been studied extensively over the past 25 years to define its role in management of variceal bleeding. The operative technique of the shunt has not changed, but more aggressive attempts at portal‐azygos disconnection have been studied for their effect on maintenance of portal perfusion. Control of variceal bleeding is achieved in about 90% of patients. Portal flow to the liver is maintained in >90% of patients with nonalcoholic etiology of portal hypertension and in 50% to 84% of patients with alcoholic cirrhosis depending on the degree of portal‐azygos disconnection. Encephalopathy and liver failure do not seem to be accelerated by DSRS but depend on the severity of the underlying liver disease. Reported survival likewise depends on the etiology of portal hypertension and the severity of liver disease: >90% survival can be achieved in portal vein thrombosis and patients with cirrhosis and normal liver function, but 50% to 60% 3‐to 5‐year survivals are reported for patients with more advanced disease. DSRS offers one treatment modality for management of variceal bleeding that must fit into an overall strategy for these patients. Full evaluation is the key to allow selection of patients for pharmactherapy, sclerotherapy, variceal decompression, or liver transplantation.
Long‐term management of variceal bleeding: The place of pharmacotherapy
Authors: Lebrec Didier 
Published: October 2004

AbstractPortal hypertension is treated by reducing portal pressure in order to prevent esophageal variceal bleeding or recurrent bleeding. Because portal hypertension depends on both elevated portal tributary blood flow and intrahepatic vascular resistance, the pharmacologic therapy of this sydrome consists in reducing portal blood flow or vascular resistance, or both. The pharmacologic prevention of first bleeding or recurrent bleeding has been performed with nonselective β‐adrenergic antagonists (propranolol or nadolol). Certain controlled studies have shown that this type of drug signifcantly reduces the risk of first bleeding by approximately 40% in patients with esophageal varices. A meta‐analysis showed that death due to bleeding was also significantly lower in the β‐blocker group than in the placebo group. Moreover, β‐blockers are effective in patients in both good and poor condition and with all types of cirrhosis. The efficacy of β‐blockers on the risk of recurrent bleeding is less clear, but these substances significantly decrease the risk of rebleeding, by approximately 30%. Recurrent bleeding in patients treated with β‐blockers is associated with the occurrence of hepatocellular carcinoma or lack of compliance. In conclusion, it is clear that different substances have portal hypotensive effects and can be used to treat or prevent complications of portal hypertension. However, other drugs should be tested, and other clinical studies are needed to identify good responders.
Role of liver transplantation in management of esophageal variceal hemorrhage
Authors: Ringe Burckhardt , Lang Hauke , Tusch Günther , Pichlmayr Rudolf 
Published: October 2004

AbstractThe management of esophageal variceal hemorrhage ranges from conservative to surgical modalities. Before introduction of liver transplantation as a potentially curative therapy of the underlying etiology, decompressive portosystemic shunt operations have been the mainstay of mostly palliative procedures Our own experience with surgery for advanced hepatic disease and portal hypertension over 20 years includes 803 liver transplantations and 201 portosystemic shunts, emphasizing our primary objective of treatment. The results after shunt surgery were favorable in Child class A candidates when performed electively and with selective decompression. After liver replacement the clinical status of the patient, including hepatic function and extrahepatic complications, had a strong influence on postoperative outcome, with the chance of excellent long‐term survival. The additional risk of previous shunt surgery for subsequent transplantation could be reduced over time. Based on this experience and reports from others there are enough reasonable arguments for shunt and transplantation. Instead of the choice being controversial, the two forms of therapy should supplement each other and be available in the same center that specializes in the treatment of patients with diseases that eventually lead to liver failure and portal hypertension Selection of either approach must depend on etiology, stage of the disease, and proper timing. Shunt procedures may be indicated in stable patients with the risk of bleeding after sclerotherapy failure, in those with contraindications to transplantation, or as a bridge to transplantation. The role of liver transplantation has been clearly established in patients with progressive or endstage (otherwise intractable) hepatobiliary disease.
Surgical management of extrahepatic portal hypertension and variceal bleeding
Authors: Orozco Hector , Takahashi Takeshi , Mercado Miguel Agel , Prado Eduardo , Chan Carlos 
Published: October 2004

AbstractVariceal bleeding remains an important complication in extrahepatic portal vein thrombosis (EPVT). As for portal hypertension due to other etiologies, an elective treatment to decrease the risk of subsequent rebleeding is warranted. The results of the Sugiura‐Futagawa procedure (SP) in 38 patients with variceal bleeding secondary to EPVT are reported: 20 women and 18 men, with a mean age of 28±2 years (SEM). Thirty‐seven patients were classified as Child‐Pugh class A, and one patient as class B. In terms of diagnosis, 45% of patients had idiopathic EPVT, and 18% had associated hypercoagulability disorders; 52% of patients had associated splenic vein thrombosis. The SP was completed in two surgical stages in 18 patients and in one surgical stage in 14; 6 patients had only the abdominal stage. One patient had mild postoperative encephalopathy, and three patients rebled at long‐term follow‐up study. There were two operative deaths. Actuarial survival was 70% at 64 months. It is concluded that the SP is an excellent alternative for patients with variceal bleeding secondary to EPVT.
Acute variceal hemorrhage: The persistent bleeder. A plea for management
Authors: Barsoum Maged S. , Boulos Fathi I. , Aly Abdel Motty H. , Saad Mohamed , Soliman Moustafa A. , Doss Wahid H. , Zakaria Serag , Thakeb Fouad 
Published: October 2004

AbstractA group of 1910 patients with acutely bleeding esophagogastric varices were managed in the Kasr El Aini sclerotherapy project; 458 of the patients (24%) were lost to follow‐up. The remaining patients were studied in five groups: group I (294/401 patients), rigid versus flexible sclerotherapy; group II (254/336 patients), intravariceal versus paravariceal sclerotherapy; group III (174/227 patients), timing of initial sclerotherapy and the optimum frequency of sclerotherapy sessions; group IV (80/99 patients), splenectomy devascularization operation alone versus combined surgery with sclerotherapy; group V (650/847 patients), management of failures of and recurrences after sclerotherapy. The mean period of follow‐up was 72 months. Rigid sclerotherapy was significantly superior to flexible sclerotherapy for emergency control of acute bleeding but was associated with significantly more morbidity. Paravariceal injection achieved insignificantly better initial control of bleeding and had more morbidity than intravariceal injection, which obliterated the varices in a significantly larger proportion of patients. Emergency injection of the acute bleeder should be carried out soon after admission, with sclerotherapy sessions repeated every 2 weeks. Combined sclerotherapy with splenectomy and devascularization was significantly more effective for controlling bleeding than surgery alone. Surgery should be done without delay for continued bleeding after the second attempt of sclerotherapy and in patients who rebleed after their third sclerotherapy session. Survival, however, was not significantly improved by the different modalities of sclerotherapy.