bluuebunny/crossref_metadata_2025 huggingface dataset:
Trace Heavy Metals Associated with Crude Oil: A Case Study of Ebocha‐8 Oil‐Spill‐Polluted Site in Niger Delta, Nigeria
Authors: Osuji Leo C. , Onojake Chukwunedum M.
Published: November 2004

The Ebocha‐8 oil‐spill‐polluted site was identified as study site according to field reconnaissance surveys of oil‐polluted sites in Obiobi/Obrikom prospect area of Niger Delta. A sampling area was delimited at each of the oil‐spill‐affected sites by the grid technique, and soils were collected at surface (0–15 cm) and subsurface (15–30 cm) depths from three replicate quadrats. A geographically similar, unaffected area, located in 50‐m distance from each contaminated site, was chosen as control site. Trace heavy metals, Ni, V, Cu, Cd, and Pb, which are normal constituents of crude oil, were determined in the soils by atomic‐absorption spectrophotometry after pre‐extraction of cations with dithionite‐citrate carbonate. Ni varied from 0.53 to 18.00 mg/kg, Cu from 0.15 to 0.30 mg/kg, and Pb from 0.32 to 0.80 mg/kg in surface and subsurface soils, respectively; Cd and V were less than 0.20 mg/kg in all sampled plots. Ni, Cu, and Pb were more enhanced (P<0.05) in the oil‐spill‐polluted soils, especially at surface depth, and this may be attributed to the fact that metal profiles in polluted soils penetrate a little below the 10‐cm region, even after many years, thereby making the metal concentration in surface soils usually higher. Whilst the Ebocha‐8 oil spillage may be responsible, at least in part, for the enhanced concentrations and paucity of variations in the metal concentrations of sampled plots, other factors such as the physicochemical characteristics of soils (e.g., soil pH and organic‐matter content) and relative mobility of these metals, as well as the intense rainfall and flooding that preceded the period of sampling, may also have contributed in part. Enhanced levels of these micronutrients in the soils may result in enhanced absorption by plants, which may bring about possible bioaccumulation by such plants and the animals that depend on them for survival, and all of these may lead to toxic reactions along the food chain.
Novel simultaneous combination chemical thrombolysis/rheolytic thrombectomy therapy for acute critical limb ischemia: The power‐pulse spray technique
Authors: Allie David E. , Hebert Chris J. , Lirtzman Mitchell D. , Wyatt Charles H. , Keller V. Antoine , Khan Mohamed H. , Barker Esmond A. , McElderry Michael W. , Khan Muhammad A. , Fail Peter S. , Stagg Samuel J. , Mitran Elena V. , Chaisson Gary , Allie Sonja D. , Allie Adam A. , Walker Craig M.
Published: November 2004

The novel power‐pulse spray (P‐PS) technique maximizes and combines the advantages and minimizes the disadvantages of both chemical thrombolysis (CT) and rheolytic thrombectomy (RT). Forty‐nine consecutive patients with iliofemoral thrombotic occlusion were treated via P‐PS technique. Using a 6 Fr RT catheter, saline prime was exchanged for thrombolytic solution [group 1, 10–20 mg tenecteplase (TNK)/50 cc saline, n = 25; group 2, 1,000,000 urokinase (UK)/50 cc saline, n = 24]. The outflow port was closed, then the catheter was advanced at 1 mm increments while pulsing lytic agent. After 30‐min lysis time, RT and definitive treatment of the underlying stenosis were performed. Procedure success was 23/25 (92%) and 22/24 (91.6%) for group 1 and 2, respectively. The mean total procedure time was 72 and 75 min in group 1 and 2, respectively. Thirty‐day limb salvage was 91% in both groups. There were no major surgical complications. The P‐PS technique is safe and effective using either UK or TNK, offering several potential advantages over monotherapy, including more rapid revascularization, decreases systemic lytic exposure and bleeding complications while facilitating both CT and RT capacity and efficacy. Catheter Cardiovasc Interv 2004;63:512–522. © 2004 Wiley‐Liss, Inc.
Prosthetic mitral valvuloplasty
Authors: Hurst Frank P. , Caravalho Joseph , Wisenbaugh Thomas W.
Published: November 2004

A 78‐year‐old man underwent mitral valve replacement with a no. 33 Hancock porcine bioprosthesis for severe mitral regurgitation. Postoperatively, a transthoracic echocardiogram (TTE) revealed a mean mitral valve gradient (MVG) of 4 mm Hg, a calculated mitral valve area (MVA) of 2.8 cm2, and no mitral regurgitation. Eighteen months later, he presented to the emergency room with progressive dyspnea. Repeat TTE demonstrated severe mitral stenosis (MVG, 16 mm Hg; MVA, 0.9 cm2). The patient was deemed high risk for a repeat valve replacement, and percutaneous valvuloplasty was performed with an Inoue balloon catheter inflated to 26 mm. The patient's symptoms dramatically improved, as did his hemodynamics (MVG, 5 mm Hg; MVA, 1.6 cm2). There was no evidence of mitral regurgitation and the successful results were maintained after 10 months of follow‐up. Since its introduction in 1987, there have been only nine cases reporting successful balloon valvulotomy in prosthetic mitral valves. While percutaneous valvulotomy is the intervention of choice for native mitral stenosis, it is rarely performed in prosthetic valves, with surgical valve replacement being the treatment of choice. Our case was successful and may suggest a niche to reconsider using the procedure in certain clinical circumstances. Catheter Cardiovasc Interv 2004;63:503–506. © 2004 Wiley‐Liss, Inc.
New device for percutaneous closure of aortopulmonary collaterals
Authors: Hijazi Ziyad M.
Published: November 2004

A 4.5‐month‐old infant with tetralogy of Fallot, pulmonary atresia, and multiple aortopulmonary collaterals underwent successful occlusion of the collaterals using a new device. This new plug (Amplatzer vascular plug) is a self‐expandable cylindrical device made of nitinol wire mesh. The device is available in sizes from 4 to 16 mm in 2 mm increment. The device can be used in patients with aortopulmonary collaterals, pulmonary arteriovenous malformations, venovenous collaterals, shunts, coronary fistulas, and certain type of patent ductus arteriosus. Catheter Cardiovasc Interv 2004;63:482–485. © 2004 Wiley‐Liss, Inc.
Lewis Adducts of the Side‐On End‐On Dinitrogen‐Bridged Complex [{(NPN)Ta}2(μ‐H)2(μ‐η1:η2‐N2)] with AlMe3, GaMe3, and B(C6F5)3: Synthesis, Structure, and Spectroscopic Properties
Authors: Studt Felix , MacKay Bruce A. , Johnson Samuel A. , Patrick Brian O. , Fryzuk Michael D. , Tuczek Felix
Published: November 2004

Reaction of the side‐on end‐on dinitrogen complex [{(NPN)Ta}2(μ‐H)2(μ‐η1:η2‐N2)] (1; in which NPN=(PhNSiMe2CH2)2PPh), with the Lewis acids XR3 results in the adducts [{(NPN)Ta}2(μ‐H)2(μ‐η1:η2‐NNXR3)], XR3=GaMe3 (2), AlMe3 (3), and B(C6F5)3 (4). The solid‐state molecular structures of 2, 3, and 4 demonstrate that the NN bond length increases relative to those found in 1 by 0.036, 0.043, and 0.073 Å, respectively. In solution complexes 2–4 are fluxional as evidenced by variable‐temperature 1H NMR spectroscopy. The 15N{1H} NMR spectra of 2–4 are reported; furthermore, their vibrational properties and electronic structures are evaluated. The vibrational structures are found to be closely related to that of the parent complex 1. Detailed spectroscopic analysis on 2–4 leads to the identification of the theoretically expected six normal modes of the Ta2N2 core. On the basis of experimental frequencies and the QCB‐NCA procedure, the force constants are determined. Importantly, the NN force constant decreases from 2.430 mdyn Å−1 in 1 to 1.876 (2), 1.729 (3), and 1.515 mdyn Å−1 (4), in line with the sequence of NN bond lengths determined crystallographically. DFT calculations on a generic model of the Lewis acid adducts 2–4 reveal that the major donor interaction between the terminal nitrogen atom and the Lewis acid is mediated by a σ/π hybrid molecular orbital of N2, corresponding to a σ bond. Charge analysis performed for the adducts indicates that the negative charge on the terminal nitrogen atom of the dinitrogen ligand increases with respect to 1. The lengthening of the NN bond observed for the Lewis adducts is therefore explained by the fact that charge donation from the complex fragment into the π* orbitals of dinitrogen is increased, while electron density from the NN bonding orbitals pσ and πh is withdrawn due to the σ interaction with the Lewis acid.
The Role of Physical Environment on Molecular Electromechanical Switching
Authors: Flood Amar H. , Peters Andrea J. , Vignon Scott A. , Steuerman David W. , Tseng Hsian‐Rong , Kang Seogshin , Heath James R. , Stoddart J. Fraser
Published: November 2004

The influences of different physical environments on the thermodynamics associated with one key step in the switching mechanism for a pair of bistable catenanes and a pair of bistable rotaxanes have been investigated systematically. The two bistable catenanes are comprised of a cyclobis(paraquat‐p‐phenylene) (CBPQT4+) ring, or its diazapyrenium‐containing analogue, that are interlocked with a macrocyclic polyether component that incorporates the strong tetrathiafulvalene (TTF) donor unit and the weaker 1,5‐dioxynaphthalene (DNP) donor unit. The two bistable rotaxanes are comprised of a CBPQT4+ ring, interlocked with a dumbbell component in which one incorporates TTF and DNP units, whereas the other incorporates a monopyrrolotetrathiafulvalene (MPTTF) donor and a DNP unit. Two consecutive cycles of a variable scan rate cyclic voltammogram (10–1500 mV s−1) performed on all of the bistable switches (∼1 mM) in MeCN electrolyte solutions (0.1 M tetrabutylammonium hexafluorophosphate) across a range of temperatures (258–303 K) were recorded in a temperature‐controlled electrochemical cell. The second cycle showed different intensities of the two features that were observed in the first cycle when the cyclic voltammetry was recorded at fast scan rates and low temperatures. The first oxidation peak increases in intensity, concomitant with a decrease in the intensity of the second oxidation peak. This variation changed systematically with scan rate and temperature and has been assigned to the molecular mechanical movements within the catenanes and rotaxanes of the CBPQT4+ ring from the DNP to the TTF unit. The intensities of each peak were assigned to the populations of each co‐conformation, and the scan‐rate variation of each population was analyzed to obtain kinetic and thermodynamic data for the movement of the CBPQT4+ ring. The Gibbs free energy of activation at 298 K for the thermally activated movement was calculated to be 16.2 kcal mol−1 for the rotaxane, and 16.7 and 19.2 kcal mol−1 for the bipyridinium‐ and diazapyrenium‐based bistable catenanes, respectively. These values differ from those obtained for the shuttling and circumrotational motions of degenerate rotaxanes and catenanes, respectively, indicating that the detailed chemical structure influences the rates of movement. In all cases, when the same bistable compounds were characterized in an electrolyte gel, the molecular mechanical motion slowed down significantly, concomitant with an increase in the activation barriers by more than 2 kcal mol−1. Irrespective of the environment—solution, self‐assembled monolayer or solid‐state polymer gel—and of the molecular structure—rotaxane or catenane—a single and generic switching mechanism is observed for all bistable molecules.
New approaches in the treatment of myelofibrosis
Authors: Hennessy Bryan T. , Thomas Deborah A. , Giles Francis J. , Kantarjian Hagop , Verstovsek Srdan
Published: November 2004

Myelofibrosis with myeloid metaplasia (MMM) is a chronic clonal neoangiogenesis disorder characterized by bone marrow fibrosis and neoangiogensis with extramedullary hematopoiesis. Identification of prognostic factors associated with MMM have not impacted the treatment of the disease, which continues to be palliative with the exception of allogeneic stem cell transplantation (SCT) for potential long‐term disease‐free survival in selected patients. Additional insights into the pathophysiology of MMM have resulted in the use of novel therapeutic strategies in the treatment of this disease. The rationale for the investigation of these agents in MMM and the status of clinical trials with various modalities such as angiogenesis inhibitors (e.g., thalidomide), tyrosine kinase inhibitors (e.g., imatinib mesylate), farnesyl transferase inhibitors (e.g., R115777), and other agents are reviewed, in addition to the potential roles of autologous and allogeneic SCT. Cancer 2005. © 2004 American Cancer Society.
Recent perspectives in the role of chemotherapy in the management of advanced nasopharyngeal carcinoma
Authors: Ma Brigette B. Y. , Chan Anthony T. C.
Published: November 2004

BACKGROUND

Recent advances in the treatment of nasopharyngeal carcinoma (NPC) have transpired into better treatment outcomes for patients with locoregionally advanced NPC, and have broadened the chemotherapeutic options for patients with metastatic disease.

METHODS

Data for this review were identified through searches of articles published in PubMed, MEDLINE, and abstracts from selected conference proceedings up to 2004.

RESULTS

The results of two meta‐analyses and at least six randomized trials supported a survival benefit with the use of concurrent chemotherapy (e.g., platinum, tegafur‐uracil [UFT)] and standard fractionated radiotherapy (with or without adjuvant chemotherapy) in the management of patients with locoregionally advanced NPC (nonmetastatic Stage III/IV disease, according to the staging system of the International Union Against Cancer). For those patients with metastatic NPC, platinum‐based doublets using newer agents such as gemcitabine and the taxanes are reported to be better tolerated and can yield response rates comparable to those obtained with older, multidrug regimens.

CONCLUSIONS

The current study reviewed the latest literature and pertinent issues concerning the role of chemotherapy in the treatment of patients with metastatic and locoregionally advanced NPC. Cancer 2005. © 2004 American Cancer Society.
Spin‐Coating Preparation of Highly Ordered Photoluminescent Films of Layered PbI2‐Aminoalkyloxysilane Perovskites
Authors: Cheng Zi‐Yong , Shi Bao‐Li , Gao Bao‐Xiang , Pang Mao‐Lin , Wang Shu‐Yun , Han Yan‐Chun , Lin Jun
Published: November 2004

By utilising 3‐aminopropyltrimethoxysilane (APTMOS) cations and PbI2 as the organic and inorganic precursors, respectively, a spin‐coated film of a layered perovskite‐type organic/inorganic derivative of APTMOS‐PbI4 was prepared. The structure of APTMOS‐PbI4 was characterised by X‐ray diffraction (XRD), UV/Vis absorption and infrared red spectroscopy (IR). The film showed green emission from the excitons of the inorganic layers and a weak blue emission related to the small amount of gel of adjacent APTMOS cations. Furthermore, the significant effect of the size of the inorganic framework on the cross‐linking degree of APTMOS molecules is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Transplantation of Bone Marrow Cells Reduces Ccl4–Induced Liver Fibrosis in Mice
Authors: Sakaida Isao , Terai Shuji , Yamamoto Naoki , Aoyama Koji , Ishikawa Tsuyoshi , Nishina Hiroshi , Okita Kiwamu
Published: November 2004

We investigated the effect of bone marrow cell (BMC) transplantation on established liver fibrosis. BMCs of green fluorescent protein (GFP) mice were transplanted into 4–week carbon tetrachloride (CCl4)-treated C57BL6 mice through the tail vein, and the mice were treated for 4 more weeks with CCl4 (total, 8 weeks). Sirius red and GFP staining clearly indicated migrated BMCs existing along with fibers, with strong expression of matrix metalloproteinase (MMP)–9 shown by anti-MMP–9 antibodies and

in situ

hybridization. Double fluorescent immunohistochemistry showed the expression of MMP–9 on the GFP–positive cell surface. Film

in situ

zymographic analysis revealed strong gelatinolytic activity in the periportal area coinciding with the location of MMP–9-positive BMCs. Four weeks after BMC transplantation, mice had significantly reduced liver fibrosis, as assessed by hydroxyproline content of the livers, compared to that of mice treated with CCl4 alone. Subpopulation of Liv8–negative BMCs was responsible for this fibrolytic effect.

In conclusion

, mice with BMC transplants with continuous CCl4 injection had reduced liver fibrosis and a significantly improved survival rate after BMC transplantation compared with mice treated with CCl4 alone. This finding introduces a new concept for the therapy of liver fibrosis.

Supplementary material for this article can be found on the Hepatology website

(
http://interscience.wiley.com/jpages/0270–9139/suppmat/index.html
). (Hepatology 2004;40:1304-1311.)
Treatment With Pegylated Interferon and Ribavarin in Hcv Infection With Genotype 2 Or 3 for 14 Weeks: A Pilot Study
Authors: Dalgard Olav , Bjøro Kristian , Hellum Kjell Block , Myrvang Bjørn , Ritland Ståle , Skaug Kjell , Raknerud Nils , Bell Helge
Published: November 2004

The aim of this study was to determine the efficacy of 14 weeks of treatment in patients infected with hepatitis C virus (HCV) genotype 2 or 3 who achieve early virological response (EVR). In a noncontrolled multicenter trial, 122 treatment–naive patients received 1.5 μg/kg pegylated interferon alfa–2b subcutaneously once weekly and 800 to 1,400 mg/d ribavirin based on body weight. Treatment was stopped at week 14 in patients with EVR, defined as undetectable HCV RNA at weeks 4 and 8. Patients without EVR were assigned to 24 weeks of treatment. The primary end point was sustained virological response (SVR), defined as undetectable HCV RNA 24 weeks after end of treatment. Among the 122 patients, 95 (78%) had EVR and received 14 weeks of treatment. The remaining 27 (22%) were treated for 24 weeks. SVR was obtained in 85 (90%) of 95 patients in the 14–week treatment group and 15 of (56%) 27 in the 24–week treatment group. Altogether, SVR was obtained in 100 of 122 patients (82%; 95% CI, 75%–89%). SVR after 14 weeks of treatment was achieved more frequently among genotype 3a patients with low viral load compared with high viral load (98% vs. 79%;

P

= .019). Logistic regression analysis showed that absence of bridging fibrosis/cirrhosis was the only independent predictor of SVR.

In conclusion

, patients with genotype 2 or 3 and EVR obtained a high SVR after 14 weeks of treatment. The results need to be confirmed in a randomized, controlled study before this treatment approach can be recommended, particularly for patients with genotype 3 and high viral load or severe fibrosis. (Hepatology 2004;40: 1260-1265.)
Viral Kinetics During Antiviral Therapy in Patients With Chronic Hepatitis C and Persistently Normal Alt Levels
Authors: Kronenberger Bernd , Herrmann Eva , Micol Florence , von Wagner Michael , Zeuzem Stefan
Published: November 2004

The aim of the present study was to compare viral kinetics between patients with chronic hepatitis C and persistently normal alanine aminotransferase (ALT) levels and those with elevated ALT levels. Kinetic parameters were derived from nonlinear, least square fitting of serum hepatitis C virus RNA quantifications collected from patients with chronic hepatitis C and persistently normal (n = 20) and elevated (n = 19) ALT levels before and during treatment with 180 μg pegylated interferon α–2a once weekly plus daily ribavirin. Patients with chronic hepatitis C and persistently normal ALT levels showed a trend to lower pretreatment infected cell loss (δ) (

P

= .13) but no differences in efficacy of blocking virus production (ε) and infected cell loss during treatment (

mδ

) compared with patients with elevated ALT levels. Differences were significant for

ε

(

P

= .02) and δ (

P

= .04) when applying updated “healthy” levels for ALT (0.75 times and 0.63 times upper limit of normal for male and female patients, respectively). A significant reduction of the kinetic parameters ε, δ, and

m

δ was observed in patients with elevated γ–glutamyltranspeptidase (GGT) levels compared with patients with normal GGT levels (

P

= .02,

P

= .005, and

P

= .02, respectively).

In conclusion

, viral kinetics are similar in patients with chronic hepatitis C and persistently normal ALT levels and those with elevated ALT levels. However, in patients with elevated GGT levels, a major association with reduced efficacy of blocking virus production and lower infected cell loss was observed. These data show that virological response in patients with chronic hepatitis C is less associated with baseline ALT than with GGT levels. (Hepatology 2004;40:1442-1449.)
Inhibition of T–Cell Responses by Hepatic Stellate Cells Via B7–H1-Mediated T–Cell Apoptosis in Mice
Authors: Yu Ming–Chin , Chen Cheng–Hsu , Liang Xiaoyan , Wang Lianfu , Gandhi Chandrashekhar R. , Fung John J. , Lu Lina , Qian Shiguang
Published: November 2004

In the injured liver, hepatic stellate cells (HSCs) secrete many different cytokines, recruit lymphocytes, and thus participate actively in the pathogenesis of liver disease. Little is known of the role of HSCs in immune responses. In this study, HSCs isolated from C57BL/10 (H2b) mice were found to express scant key surface molecules in the quiescent stage. Activated HSCs express major histocompatibility complex class I, costimulatory molecules, and produce a variety of cytokines. Stimulation by interferon γ (IFN–γ) or activated T cells enhanced expression of these molecules. Interestingly, addition of the activated (but not quiescent) HSCs suppressed thymidine uptake by T cells that were stimulated by alloantigens or by anti–CD3-mediated T–cell receptor ligation in a dose–dependent manner. High cytokine production by the T cells suggests that the inhibition was probably not a result of suppression of their activation. T–cell division was also found to be normal in a CFSE dilution assay. The HSC–induced T–cell hyporesponsiveness was associated with enhanced T–cell apoptosis. Activation of HSCs was associated with markedly enhanced expression of B7–H1. Blockade of B7–H1/PD–1 ligation significantly reduced HSC immunomodulatory activity, suggesting an important role of B7–H1.

In conclusion

, the bidirectional interactions between HSCs and immune cells may contribute to hepatic immune tolerance. (Hepatology 2004;40:1312-1321.)
Coumarinolignans from the Root of Formosan Antidesma pentandrum var. barbatum
Authors: Chen Yu‐Chang , Cheng Ming‐Jen , Lee Shoiw‐Ju , Dixit Ajay Kumar , Ishikawa Tsutomu , Tsai Ian‐Lih , Chen Ih‐Sheng
Published: November 2004

Four new coumarinolignans, antidesmanin A (=7‐(1,1‐dimethylallyl)‐2,3‐dihydro‐3‐(4‐hydroxy‐3,5‐dimethoxyphenyl)‐10‐methoxy‐2‐methyl‐6H‐1,4,5‐trioxaphenanthren‐6‐one; 1), antidesmanin B (=3,7‐bis(1,1‐dimethylallyl)‐2,3‐dihydro‐2‐(4‐hydroxy‐3‐methoxyphenyl)‐10‐methoxy‐6H‐1,4,5‐trioxaphenanthren‐6‐one; 2), antidesmanin C (=2,7‐bis‐(1,1‐dimethylallyl)‐2,3‐dihydro‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐10‐methoxy‐6H‐1,4,5‐trioxaphenanthren‐6‐one; 3) and antidesmanin D (=2‐(3,4‐dihydroxyphenyl)‐3,7‐bis(1,1‐dimethylallyl)‐2,3‐dihydroxy‐10‐methoxy‐6H‐1,4,5‐trioxaphenanthren‐6‐one or 3‐(3,4‐dihydroxyphenyl)‐2,7‐bis(1,1‐dimethylallyl)‐2,3‐dihydro‐10‐methoxy‐6H‐1,4,5‐trioxaphenanthren‐6‐one; 4) have been isolated from the root of the Formosan Antidesma pentandrum var. barbatum. The structures of these new compounds were elucidated by spectroscopic data. Compounds 1–3 exhibited marginal cytotoxicity against MCF‐7 (breast) and SF‐268 (CNS) cancer cell lines in vitro.
ent‐Clerodanoids from Isodon scoparius
Authors: Xiang Wei , Li Rong‐Tao , Song Qi‐Shi , Na Zhi , Sun Han‐Dong
Published: November 2004

Three new ent‐clerodane diterpenoids, isoscoparin A, B, and C (1–3), were isolated from Isodon scoparius. Their structures were determined by NMR‐spectra analysis. The biogenetic implication of the diterpenes from Isodon genus is discussed.
Developmental regulation and cellular distribution of human cytosolic malate dehydrogenase (MDH1)
Authors: Lo Agnes Shuk‐Yee , Liew Choong‐Tsek , Ngai Sai‐Ming , Tsui Stephen Kwok‐Wing , Fung Kwok‐Pui , Lee Cheuk‐Yu , Waye Mary Miu‐Yee
Published: November 2004

Human cyotsolic malate dehydrogenase (MDH1) is important in transporting NADH equivalents across the mitochondrial membrane, controlling tricarboxylic acid (TCA) cycle pool size and providing contractile function. Cellular localization studies indicate that MDH1 mRNA expression has a strong tissue‐specific distribution, being expressed primarily in cardiac and skeletal muscle and in the brain, at intermediate levels in the spleen, kidney, intestine, liver, and testes and at low levels in lung and bone marrow. The observed MDH1 localizations reflect the role of NADH in the support of a variety of functions in different organs. These functions are primarily related to aerobic energy production for muscle contraction, neuronal signal transmission, absorption/resorption functions, collagen‐supporting functions, phagocytosis of dead cells, and processes related to gas exchange and cell division. During neonatal development, MDH1 is expressed in human embryonic heart as early as the 3rd month and then is over‐expressed from the 5th month until the birth. The expression of MDH1 is maintained in the adult heart but is not present in levels as high as in the fetus. Finally, over‐expression of MDH1 is found in left ventricular cardiac muscle of dilated cardiomyopathy (DCM) patients when contrasted to the diseased non‐DCM and normal heart muscle by in situ hybridization and Western blot. These observations are compatible with the activation of glucose oxidation in relatively hypoxic environments of fetal and hypertrophied myocardium. © 2004 Wiley‐Liss, Inc.
Homeostasis of neuroactive amino acids in cultured cerebellar and neocortical neurons is influenced by environmental cues
Authors: Waagepetersen Helle , Melø Torun , Schousboe Arne , Sonnewald Ursula
Published: November 2004

Neuronal function is highly influenced by the extracellular environment. To study the effect of the milieu on neurons from cerebellum and neocortex, cells from these brain areas were cultured under different conditions. Two sets of cultures, one neocortical and one cerebellar neurons, were maintained in media containing [U‐13C]glucose for 8 days at initial concentrations of 12 and 28 mM glucose, respectively. Other sets of cultures (8 days in vitro) maintained in a medium containing initially 12 mM glucose were incubated subsequently for 4 hr either by addition of [U‐13C]glucose to the culture medium (final concentration 3 mM) or by changing to fresh medium containing [U‐13C]glucose (3 mM) but without glutamine and fetal calf serum. 13C Nuclear magnetic resonance (NMR) spectra revealed extensive γ‐aminobutyric acid (GABA) synthesis in both cultured neocortical and cerebellar neurons after maintenance in medium containing [U‐13C]glucose for 8 days, whereas no aspartate labeling was observed in these spectra. Mass spectrometry analysis, however, revealed high labeling intensity of aspartate, which was equal in the two types of neurons. Addition of [U‐13C]glucose (4 hr) on Day 8 in culture led to a similar extent of labeling of GABA in neocortical and in cerebellar cultures, but the cellular content of GABA was considerably higher in the neocortical neurons. The cellular content of alanine was similar regardless of culture type. Comparing the amount of labeling, however, cerebellar neurons exhibited a higher capacity for alanine synthesis. This is compatible with the fact that cerebellar neurons could ameliorate a low alanine content after culturing in low glucose (12 mM) by a 4‐hr incubation in medium containing 3 mM glucose. A low glucose concentration during the culture period and a subsequent medium change were associated with decreases in glutathione and taurine contents. Moreover, glutamate and GABA contents were reduced in cerebellar cultures under either of these conditions. In neocortical neurons, the GABA content was decreased by simultaneous exposure to low glucose and change of medium. These conditions also led to an increase in the aspartate content in both types of cultures, although most pronounced in the neocortical neurons. Further experiments are needed to elucidate these phenomena that underline the impact of extracellular environment on amino acid homeostasis. © 2004 Wiley‐Liss, Inc.
Surgical treatment for gastric carcinoma in the elderly
Authors: Coniglio Arianna , Tiberio Guido Alberto Massimo , Busti Monica , Gaverini Giacomo , Baiocchi Luca , Piardi Tullio , Ronconi Maurizio , Giulini Stefano Maria
Published: November 2004

Background and Objectives

The incidence of gastric cancer is increasing in the elderly. The aim of this study is to evaluate the impact of advanced age (≥80 years) on morbidity, mortality and late outcome after curative surgery for gastric cancer.

Methods

The cases of 30 octogenarians (Group A) with gastric cancer who underwent surgical treatment in our Institution from 1990 to 2003 were reviewed and compared to a simultaneous group of 228 younger patients (Group B).

Results

The rate of resective and curative procedures was not different in the two groups, although the American Society of Anaesthesiologists (ASA) risk was significantly higher in the elderly (P < 0.001) and the lymphatic dissection was less extended in group A. In the two groups, the curability was directly correlated to the cancer stage, but not affected by the ASA risk. The postoperative morbidity and mortality rates were similar in the two groups and were not related to the ASA risk. Considering the mortality for gastric cancer alone, the two groups showed a similar survival rate, only correlated to the cancer stage.

Conclusions

In the elderly, an oncologically correct surgical procedure can safely be prosecuted with satisfactory immediate and late results. J. Surg. Oncol. 2004;88:201–205. © 2004 Wiley‐Liss, Inc.
Haemostatic alterations in colorectal cancer: Perspectives for future treatment
Authors: Lykke Jakob , Nielsen Hans Jørgen
Published: November 2004

The role of the haemostatic system in colorectal cancer (CRC) is reviewed. Correlations between the activation of the haemostatic system and overall survival have been suggested. Experimental studies indicate that the haemostatic system plays a key role in growth, invasion and dissemination of tumour cells, and in tumour related angiogenesis. Additional activation by the surgical trauma and postoperative infections are discussed. Finally, anti‐cancer modalities directed against regulation of the haemostatic system in CRC are considered. J. Surg. Oncol. 2004;88:269–275. © 2004 Wiley‐Liss, Inc.
Green coconut water for intravenous use: Trace and minor element content
Authors: Petroianu Georg A. , Kosanovic Melita , Shehatta Ibrahim Saad , Mahgoub Bahaa , Saleh Ayman , Maleck Wolfgang H.
Published: November 2004

Green coconut water (GCW; liquid endosperm) is sterile and has been used in the past in remote locations and/or during armed conflicts as a short‐term intravenous hydration fluid. It is also conceivable to use GCW for total parenteral nutrition (TPN) under similar circumstances. Patients on TPN need elemental supplementation. Although data on the major elements (calcium, magnesium, potassium, sodium, and phosphorus) found in GCW are abundant, very limited information concerning trace and minor element content in GCW is available. The purpose of this study was to determine trace and minor element content in GCW. Major elements were arbitrarily defined as those with a GCW concentration in the mM range, as opposed to minor ones in the μM range and trace elements in the nM range. The values determined show the great variability typical for samples of plant origin. Under TPN conditions, GCW (1,000 mL/day) would be able to provide adequate supplementation of manganese (12 ± 5 μmol/L) and possibly zinc (6 ± 1 μmol/L) but not chromium (not detected, i.e., less than 9 nM/L) and copper (105 ± 100 nM/L). With respect to elements usually considered nonessential or even toxic, GCW compares favorably with commonly used TPN solutions, most notably for aluminium content (740 ± 360 nM/L) and cadmium (7 ± 4 nM/L). The levels of lead (150 ± 67 nmol/L) and barium (600 ± 300 nmol/L) were similar to those typically found in commercial TPN solutions. Those of strontium (8 ± 4 μmol/L) are higher but unlikely to be harmful. In conclusion, although GCW is not completely equivalent to high‐tech (and high‐cost) TPN solutions with trace element supplements, it still may provide sufficient support of at least some of the trace elements if used as a substitute. The GCW investigated by us is, at least, not toxic. However, our results for several trace elements are much lower than values previously reported in the literature, especially in coconuts from “polluted” areas. GCW from polluted soil might be easily toxic if used intravenously. J. Trace Elem. Exp. Med. 17:273–282, 2004. © 2004 Wiley‐Liss, Inc.
Modellierung mehrfach gestufter, teleskopierbarer, spielbehafteter Maschinenelemente
Authors: Barthels Pierre , Wauer Jörg
Published: November 2004

Gestufte, spielbehaftete, teleskopartig gegeneinander verschiebbare Maschinenelemente werden durch die Bewegung in der Ebene senkrecht zur Teleskopierrichtung zu Transversalschwingungen angeregt. Diese Schwingungen führen in technischen Anwendungen zu einer Reduzierung der Leistungsfähigkeit und zu Sicherheitsproblemen. Die Entwicklung von Maßnahmen zur Schwingungsunterdrückung ist deshalb besonders wichtig. Ein erster Schritt dazu ist die Modellbildung und das Studium der entstehenden Schwingungen. Aus Sicht der Mechanik handelt es sich bei der Modellierung um nichtlineare Feldprobleme mit variabler Geometrie der betreffenden Festkörpersysteme. Materielle Begrenzungen einzelner Komponenten verschieben sich beim Teleskopieren entlang der Begrenzungen anderer Bauteile und definieren so komplizierte Rand bzw. Übergangsbedingungen. Das Spiel führt zu nichtlinearen Effekten. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability of digital force control in the presence of damping
Authors: Stréli Tamás , Kisfalusi Krisztián , Stéphán Gábor
Published: November 2004

In the plain of the proportional gain and the ratio of the natural and sampling frequencies, the stability charts of digital force control are constructed for one degree of freedom mechanical models with large variety of viscous damping parameters. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of Nonlinear Mechanical Systems under Constraints with the Particle Swarm Method
Authors: Sedlaczek Kai , Eberhard Peter
Published: November 2004

In recent years, stochastic optimization methods have gained increasing attention in parameter optimization of mechanical systems. Most popular techniques are Evolutionary Computation and the Simulating Annealing algorithm, which are applied more frequently to mechanical problems due to the increasing computing resources available now. Since theses methods do not require any gradient information, they are well suited for non‐smooth or discontinuous optimization tasks occurring in nonlinear multibody systems. In addition to these techniques, Kennedy and Eberhart [5] introduced the Particle Swarm Optimization method (PSO) based on the simulation of bird flocking. In this work, the efficiency of an extended PSO algorithm has been compared with an Evolutionary Strategy (ES) [6] and an Adapted Simulated Annealing method (ASA) [4]. In order to solve optimization tasks with both equality and inequality constraints the PSO algorithm has been extended by the Augmented Lagrangian Multiplier Method [2]. The proposed method shows often superior results and is quite simple to implement. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation and experimental validation of the dynamic behavior of an electromechanically actuated multiple‐disk clutch
Authors: Treder Marco , Woernle Christoph
Published: November 2004

Automated multiple‐disk clutches in automotive drivelines are at present hydraulically or electrohydraulically actuated. The electromechanical clutch actuation represents an alternative. The subject of the investigation is a functional model of an electromechanical clutch actuator which consists of a servo motor, a reduction gear and a mechanism for the realization of the force acting on the disks. For the simulation of the dynamic behavior of the electromechanically actuated multiple‐disk clutch a detailed multibody model is developed which includes models of the electromechanical actuator and the wet multiple‐disk clutch. The multiple‐disk clutch is described by coupled partial models for the rotational and translational dynamics. The coupling parameters are the relative disk distances and the forces between the disks. The results of test bench measurements are compared to simulation results. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of Inertia on the Microscale in Homogenization
Authors: Alvermann S. , Schanz M.
Published: November 2004

When calculating effective dynamical properties of a material, inertia on the microscale is usually neglected. Here, contrary to these approaches, inertia effects are taken into account, leading to a frequency dependent microscopic behavior. Thus, a frequency dependent macroscopic constitutive equation is required. Therefore, a viscoelastic constitutive equation is applied on the macroscale. The material parameters are found using an Evolutionary Strategy. In the 1‐D case, system responses on the micro‐ and macroscale show a good agreement in a frequency range from 0 up to the first eigenfrequency of the microstructure. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling the mechanical properties of biaxial weft‐knitted fabric reinforced
Authors: Haasemann Georg , Ulbricht Volker , Brummund Jörg
Published: November 2004

The subjects of the analysis are glass/epoxy‐composites with biaxial weft knitted fabric reinforcement. This fabric combines the advantages of high in‐plane stiffness and delamination resistance provided by the biaxial and knitted fabric, respectively. The asymptotic homogenisation procedure based on the displacement method in conjunction with a finite element model provides the possibility to obtain the effective material stiffness. The effort to generate a pure 3D‐model of the unit cell would be extremely high. A solution of this problem gives the Binary Model where a simplified geometry of the interior structure is used.

Additionally, the Voigt and Reuss bounds for the Young's and shear moduli are found by using the 3D orientation averaging procedure. The results obtained with the Binary Model will be compared to these bounds and the experimental results. The work done for this paper is sponsored by the German Research Community (DFG) in the context of the priority program (SPP) no. 1123. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micromechanically‐Based Modelling in Nonlocal Crystal Plasticty
Authors: Becker Martin , Miehe Christian
Published: November 2004

Within purely local descriptions inhomogeneous plastic deformations induce an incompatibility of the intermediate configuration introduced in connection with the multiplicative split of large strain crystal plasticity. Extending the local model by inclusion of higher order gradients of the inelastic deformation restores on the one hand the compatibility of the intermediate configuration and leads on the other hand to size effects in the material behavior in analogy to experimentally observed phenomena. The underlying physical interpretation is the storage of geometrically necessary dislocations (GNDs) for plastically inhomogeneous deformations. We briefly address the relation between deformation incompatibilities and the storage of GNDs. Furthermore we consider the corresponding numerical implementation, validate our approach by means of a benchmark problem and give a short comparison to other dislocation density based as well as rather phenomenological models. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Material Forces in Standard Dissipative Solids obtained from an Incremental Variational Formulation
Authors: Zimmermann Dominik , Miehe Christian
Published: November 2004

A variational method for the definition of material forces in standard dissipative solids based on a path‐dependent incremental minimization structure is proposed. The underlying base is provided by incremental variational formulations for standard dissipative solids. For this type of inelastic constitutive response, an incremental stress potential can be constructed by a constitutive minimization principle. Then, the incremental boundary value problem of a deformed inelastic body is governed by a minimization principle. In this context dual variational settings for the definition of both the physical as well as the material forces are presented. This yields to the definition of material forces as the sensitivity of work with respect to change of Lagrangian, i.e. material coordinates. An application of the material force method to the description of elastic‐plastic fracture mechanics is given. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prenatal diagnosis for arginase deficiency by second‐trimester fetal erythrocyte arginase assay and first‐trimester ARG1 mutation analysis
Authors: Korman Stanley H. , Gutman Alisa , Stemmer Edia , Kay Barrie S. , Ben‐Neriah Ziva , Zeigler Marsha
Published: November 2004

Hyperargininemia is a progressive neurometabolic disorder caused by deficiency of hepatic cytosolic arginase I, resulting from mutations in the ARG1 gene. We diagnosed arginase deficiency in a three‐year‐old male child of first‐cousin Palestinian Arab parents. Prenatal diagnosis of an unaffected fetus was achieved in the second trimester of a subsequent pregnancy by cordocentesis and analysis of arginase activity in fetal erythrocytes. ARG1 mutation analysis in the proband revealed homozygosity for a deletion of 10 753 bp extending from the first intron to beyond the poly (A) site of the gene. This is the first gross deletion in the ARG1 gene to be identified and the first mutation to be described in an arginase‐deficient patient of this ethnic origin. The identification of the ARG1 deletion in this family enabled first‐trimester prenatal diagnosis in a subsequent pregnancy by multiplex PCR analysis performed on chorionic villous DNA. Copyright © 2004 John Wiley & Sons, Ltd.
Influences of hot stretch ratio on essential work of fracture ofin‐situmicrofibrillar poly(ethylene terephthalate)/polyethylene blends
Authors: Li Zhong‐Ming , Xie Bang‐Hu , Huang Rui , Fang Xiang‐Ping , Yang Ming‐Bo
Published: November 2004

Anin‐situmicrofibrillar blend based on poly(ethylene terephthalate) (PET) and polyethylene (PE) was fabricated through slit die extrusion, hot stretching, and quenching. The morphological characteristics of the PET phase, such as diameter and its distribution, which were observed after the matrix was etched away, appear to be dependent on the hot stretch ratio at a fixed blend composition. The increase of the hot stretching ratio makes the PET particles change from spheres and ellipsoids to rodlike particles, and finally to well‐defined microfibers. The fracture toughness of thein‐situmicrofibrillar blend was evaluated using deeply double‐edge notched tension (DDENT) specimens according to the essential work of fracture procedure. Initially, the increase of hot stretch ratio makes the specific essential work of fracture (we) rise. A maximum we appears at 25.4. Further increase of hot stretch ratio causes a slightdecrease ofwe. On the other hand, it shows that lower hot stretch ratios make the specific non‐essential work of fracture (wp) rise slightly. As it exceeds 6.4,wpdecreases substantially. It was believed that the characteristics of the PET domains were responsible for the fracture behaviors of thein‐situmicrofibrillar blend. Polym. Eng. Sci. 44:2165–2173, 2004. © 2004 Society of Plastics Engineers.
Design of calibrators for extruded profiles. Part I: Modeling the thermal interchanges
Authors: Nóbrega J. M. , Carneiro O. S. , Covas J. A. , Pinho F. T. , Oliveira P. J.
Published: November 2004

The parameters influencing the calibration/cooling stage of profile extrusion are discussed, and a numerical finite‐volume method code to model the heat transfer is described and validated. For this purpose, the numerical predictions are compared with the analytical solution of a simple problem, with results available in the literature and with those produced by a commercial software. The routines developed are then used to identify the main process parameters and boundary conditions and to estimate their relative importance. The investigation clearly shows the advantages of using several calibrators separated by annealing zones, relative to a single calibrator of the same total length, and the large impact of the contact resistance between extrudate and cooling unit while showing negligible impact of other boundary conditions. A decrease of the extrudate velocity is seen to be also an effective control parameter, but it decreases the production rates. Polym. Eng. Sci. 44:2216–2228, 2004. © 2004 Society of Plastics Engineers.
New experimental method for determination of effective diffusion coefficient of blowing agents in polyurethane foams
Authors: Modesti M. , Lorenzetti A. , Dall'Acqua C.
Published: November 2004

The effective diffusion coefficients of novel, environmentally friendly, hydrofluorocarbon (HFC) blowing agents for polyurethane foam production were measured. The method was based on gas chromatography and infrared spectroscopy measurements. The accuracy and reliability of the procedure developed were confirmed by comparisons of experimental and the predicted thermal aging curves. The slope of the aging curves (i.e., the change in thermal conductivity with time) depended only on the effective diffusion coefficients. The effective diffusion coefficients of the new HFC blowing agents were close to those of conventional hydrochlorofluorocarbon (HCFC) blowing agents, and the aging behavior of foams produced from HFC or HCFC blowing agents were similar. Polym. Eng. Sci. 44:2229–2239, 2004. © 2004 Society of Plastics Engineers.
A time‐scale approach for analysis of coalescence in processing flows
Authors: Perilla Jairo E. , Jana Sadhan C.
Published: November 2004

Coalescence of droplets in flow through capillary dies and in the filling of strip molds was investigated using experiments and time‐scale analysis. The time scales of droplet approach, droplet‐droplet interactions, and fluid drainage were compared with the time scales of flow in order to predict the extent of coalescence in each case. In the case of capillary dies, coalescence took place predominantly in the zones away from the die wall and away from the die axis, and the expanse of the coalescence zone increased with blend composition and decreased with mean shear rate. In the case of mold filling, droplet coalescence took place after the polymer flowed a characteristic distance along the mold. A semiquantitative agreement was found between the predictions and the experimental results obtained using blends of polypropylene and polystyrene. In addition to larger‐diameter droplets, long fibrils, formed by stringing of coalescing droplets, were observed. Polym. Eng. Sci. 44:2254–2265, 2004. © 2004 Society of Plastics Engineers.