bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymptotic behaviour of global classical solutions of diagonalizable quasilinear hyperbolic systems
Authors: Liu Jianli , Zhou Yi 
Published: November 2006

AbstractThis paper is concerned with the asymptotic behaviour of global classical solutions of diagonalizable quasilinear hyperbolic systems with linearly degenerate characteristic fields. Based on the existence results of global classical solutions, we prove that when t tends to infinity, the solution approaches a combination of C1 travelling wave solutions, provided that L1 ∩ L∞ norm of the initial data as well as its derivative are bounded. Application is given for the time‐like extremal surface in Minkowski space. Copyright © 2006 John Wiley & Sons, Ltd.
A review of the biological and potential therapeutic actions of Harpagophytum procumbens
Authors: Grant L. , McBean D. E. , Fyfe L. , Warnock A. M. 
Published: November 2006

AbstractHarpagophytum procumbens (Hp), commonly known as Devil's Claw is a perennial plant which thrives in arid conditions. For centuries, it has been used as a traditional treatment for a variety of illnesses, including fevers, skin complaints, arthritis and diseases of the digestive tract as well as an appetite stimulant. Since its introduction to Europe in the early twentieth century, it has become a popular antiinflammatory and analgesic preparation amongst herbalists for supportive or adjuvant treatment of degenerative joint diseases, tendonitis, headache, backache and menstrual pain. The validity of Hp as an effective antiinflammatory and analgesic preparation, particularly in the relief of arthritic symptoms, has been investigated in numerous animal, clinical and in vitro studies. Although some contradictory evidence exists, the majority of animal studies appear to indicate Hp as an effective antiinflammatory and analgesic preparation in the treatment of acute and subacute inflammation. Clinical trials support Hp as a beneficial treatment for the alleviation of pain and improvement of mobility in a variety of musculoskeletal conditions. Analysis of the in vitro and ex vivo studies that currently exist, indicate that Hp has significant effects on numerous proinflammatory markers. However, the exact mechanism(s) by which Hp may reduce inflammation remain to be elucidated. Copyright © 2006 John Wiley & Sons, Ltd.
Pterocarpus santalinus: an In Vitro study on its anti‐Helicobacter pylori effect
Authors: Narayan Shoba , Veeraraghavan Mani , Devi C. S. Shyamala 
Published: November 2006

AbstractThe anti‐H. pylori activity of Pterocarpus santalinus (PS), a traditional herb, has been assessed and compared with that of bismuth subcitrate, through in vitro studies employing rat gastric epithelial cell cultures and H. pylori isolates from gastric mucosal biopsy patients. The MIC of PS was found to be 20 µg/mL. H. pylori was co‐cultivated with rat gastric epithelial cells in the presence/absence of PS at its MIC. A reduction in the activity of urease, a normal appearance of the epithelial cells on electron microscopic examination, a decrease in lipid peroxidation and lactate dehydrogenase suggests the possible anti‐H. pylori activity of PS. Copyright © 2006 John Wiley & Sons, Ltd.
In Silico Classification of Solubility using Binary k‐Nearest Neighbor and Physicochemical Descriptors
Authors: Fredsted Berith , Brockhoff Per B. , Vind Christian , Padkjær Søren B. , Refsgaard Hanne HF. 
Published: November 2006

AbstractSolubility is a key property that highly affects both the absorption and screening efficiency of drug candidates. Here, we present an in silico k‐nearest neighbor model applying ten physicochemical descriptors which classify solubility based on a diverse set of chemical drug candidates. Data used for modeling the solubility consisted of turbidimetric solubility values at pH 7.4 for 518 drug candidates. Data were divided into a training set and a test set of 389 and 129 compounds, respectively, which additionally were binned into two classes with respect to the solubility: insoluble class: solubility ≤0.02 mg/mL and soluble class: solubility >0.02 mg/mL. Furthermore, a structural fragment analysis of soluble versus insoluble compounds was performed, and structural fragments and functional groups for which we found statistical difference in frequency between the two solubility classes were presented. Of the ten descriptors used for modeling, clog D was found to be the descriptor that separated the two solubility classes most efficiently. When the test set was classified, 84% were predicted to the right class. Validated with 12 soluble marketed drugs, the model predicted 11 of the 12 compounds to the right class. We found that the solubility model could be used to flag molecules with low solubility in an early stage of discovery projects.
What Works and What Does Not: Lessons From Experience in a Pharmaceutical Company
Authors: Martin Yvonne Connolly 
Published: November 2006

AbstractComputational chemists make two types of contributions in drug research. The traditional contribution is to develop models that predict molecular properties and so provide experimentalists with information that helps them rule out certain compounds before detailed investigation – for example, the investigation can be following up a high‐throughput screening hit or synthesizing a new molecule. Our experience suggests that such models are useful, but a corollary utility is the addition of alternative perspective of a computational chemist to the usual composition of a discovery team. This alternative perspective can lead the team to novel discoveries, independent of quantitative models. Although we, computational chemists, show the inadequacy of global models to predict octanol–water log P, pKa, permeability, and bioavailability, scientists continue to use these models. Apparently, they are accurate enough for practical purposes. Computational chemists make a second type of contribution when they devise expert systems that encode knowledge into a computer system. An example of the latter is our development of red and yellow structure alerts that suggest that a compound might be reactive or unstable (red alert) or contain unattractive functional groups (yellow alert). These expert systems are not derived from traditional quantitative modeling techniques, nor can they be. Nonetheless, our experience had been that scientists make heavy use of such computer programs and take a responsibility for suggesting improvements in the rules. Experience suggests that computational chemists make the largest impact when they focus on solving the specific problems faced by their experimentalist colleagues .
MAC and encapsulation efficiency of satellite DVB using fade mitigation techniques
Authors: Lücke Oliver , Jahn Axel , Werner Markus 
Published: November 2006

AbstractThe paper discusses cross‐layer issues of DVB‐S2 networks with adaptive coding and modulation (ACM) on the physical layer forward link. Also future return channel via satellite (RCS) systems employing adaptive schemes on the return link are analysed. Cross‐layer issues focus on medium access control (MAC) and encapsulation layer effects. Recent work of the S2 encapsulation over generic streams (GS) is described, and the effects on quality of service (QoS) scheduling for the forward link are analysed by means of simulation. A performance comparison between DVB‐S and S2, both for transport streams (TS) and GS shows a significant gain by new encapsulation and fragmentation protocols that allow fragmentation across BBFrames. Here, realistic traffic scenarios with a mix of several services as well as rain fading are taken into account. For the return link, an adaptive scheme is discussed, going beyond the current RCS standard. Several approaches for access burst structures are presented and their impact on link efficiency through padding and encapsulation overhead is simulated. Finally, burst segmentation impact on jitter is investigated. Copyright © 2006 John Wiley & Sons, Ltd.
Cross‐layer enhancement of error control techniques for adaptation layers of DVB satellites
Authors: Cantillo Juan , Lacan Jérôme , Buret Isabelle 
Published: November 2006

AbstractThis paper assesses the way error control is managed jointly by Forward Error Codes (FEC) and Cyclic Redundancy Checks (CRC) in the lower layers of today's Digital Video Broadcasting (DVB) satellites. Mathematical and simulation results clearly show that the outer block codes of the coding schemes used in DVB‐S and DVB‐S2 (Reed–Solomon and Bose–Chaudhuri–Hocquenghem, respectively) can provide very accurate error‐detection information to the receiver in addition to their basic correction task at virtually no cost, making an uncorrected error after decoding an extremely improbable event. For this reason, the workload of CRCs can be ensured safely by the FEC subsystem if a dedicated function allowing the physical layer to share its decoding information with the adaptation layer is set. This particular cross‐layer mechanism would allow freeing up the bandwidth currently used by CRCs—which adds up to 10% for more than 35% of the total number of IP packets—and pave the way for an enhanced transport of IP over DVB‐S2. Copyright © 2006 John Wiley & Sons, Ltd.
Impact of Etiologic Factors and APACHE II and POSSUM Scores in Management and Clinical Outcome of Acute Intestinal Ischemic Disorders after Surgical Treatment
Authors: Hsu Hui‐Ping , Shan Yan‐Shen , Hsieh Yu‐Hsiang , Sy Edgar D. , Lin Pin‐Wen 
Published: November 2006

AbstractBackgroundAcute intestinal ischemic disorder (AIID) is an uncommon vascular disease with high mortality. According to etiology, it can be categorized into three groups: arterial occlusive mesenteric ischemia (AOMI), mesenteric venous thrombosis (MVT), and nonocclusive mesenteric ischemia (NOMI). This study analyzes the effect of classification on surgical outcome.Patients and MethodsAll AIID patients who underwent operative treatment at National Cheng Kung University Hospital between January 1989 and August 2003 were enrolled in this study. Preoperative information on these patients was compared to find predictors of outcome.ResultsData from 77 patients (49 men and 28 women, median age 70 years) were analyzed. The etiology was AOMI in 30 patients, MVT in 19 patients, and NOMI in 28 patients. Median age was younger in MVT (54 years) than in AOMI (70 years) or NOMI (72 years). In addition, MVT usually involved the jejunum (74%, versus 31% in AOMI and 46% in NOMI), whereas both AOMI and NOMI involved ileum and colon. The patients with AOMI had shorter duration of symptoms and higher ratio of underlying hypertension than those with MVT. The overall mortality rate was 53.2% (41/77). The day 1 and day 30 mortality were 0% and 10.5% in MVT, 16.7% and 30% in AOMI, and 42.9% and 67.9% in NOMI, respectively (P < 0.05). Both the etiology and the APACHE II scores were significant risk factors for day 30 and long‐term mortality. The patients with NOMI had higher POSSUM physiologic scores than patients with MVT. The P‐POSSUM regression equation can accurately predict mortality.ConclusionsPatients with MVT had a more favorable prognosis, whereas those with NOMI had the worst outlook. The APACHE II and POSSUM scoring systems are useful in predicting the clinical outcome. Early diagnosis and classification of AIID patients are useful for aggressive treatment to improve the clinical outcome.
A Review of Mucinous Cystic Neoplasms of the Pancreas Defined by Ovarian‐type Stroma: Clinicopathological Features of 344 Patients
Authors: Goh Brian K. P. , Tan Yu‐Meng , Chung Yaw‐Fui A. , Chow Pierce K. H. , Cheow Peng‐Chung , Wong Wai‐Keong , Ooi London L. P. J. 
Published: November 2006

AbstractIntroductionDespite formal definitions of mucinous cystic neoplasms (MCNs) and intraductal papillary neoplasms (IPMNs) by the World Health Organization (WHO) and Armed Forces Institute of Pathology (AFIP), several controversies with regard to MCNs remain. The aim of this review was to determine the clinicopathological features of MCNs defined by ovarian‐type stroma (OS) as proposed by the WHO and AFIP and to compare them with MCNs defined by less stringent criteria.MethodsA MEDLINE search was conducted to identify English‐language articles on pancreatic MCNs from 1996 to 2005. Twenty‐five studies were identified. The studies were divided into 2 groups: group A included 10 studies with 344 patients whereby the presence of OS was a criteria for the diagnosis of MCNs, and group B, included 15 studies comprising 761 patients whereby the presence of OS was not mandatory for the diagnosis of MCNs.ResultsPatients in group A (MCNs as defined by OS) were almost always female (99.7%), with a mean age of 47 (range, 18–95) years. MCNs were located predominantly in the body or tail of the pancreas (94.6%) and had a mean size of 8.7 cm (range, 0.6–35 cm); 76% were symptomatic, 6.8% demonstrated ductal communication, and 27% were malignant. At a mean follow‐up of 57.5 (range, 1–264) months and 43 (range, 2–257) months after surgery, 97.9% of benign and 61.9% of malignant neoplasms were disease free, respectively. Patients in group B were older and had a higher proportion of males. Neoplasms were more evenly distributed in the pancreas, were smaller, communicated more frequently with the pancreatic duct, and were composed of a higher proportion of malignant tumors compared with group A. Their clinicopathological features were intermediate between those of group A and patients with IPMN.ConclusionPancreatic MCNs with OS have unique and distinct clinicopathological features. MCNs should be defined by the presence of OS, as it is the most reliable way of distinguishing MCNs from IPMN. Adoption of “looser” criteria will result in misclassification of some IPMNs as MCNs.
Hyperhomocysteinemia and thrombosis
Authors: Cattaneo Marco 
Published: November 2006

AbstractHomocysteine (Hcy) is a sulfhydryl amino acid derived from the metabolic conversion of methionine, which is dependent on vitamins (folic acid, B12, and B6) as cofactors or cosubstrates. In 1969, McCully first reported the presence of severe atherosclerotic lesions in patients with severe hyperhomocysteinemia and hypothesized the existence of a pathogenic link between hyperhomocysteinemia and atherogenesis. Several case‐control and cross‐sectional studies were consistent with the initial hypothesis of McCully, showing that moderate hyperhomocysteinemia is also associated with heightened risk of occlusive arterial disease. Less consistent results have been reported by prospective cohort studies of subjects who were healthy at the time of their enrollment, whereas prospective cohort studies of patients with overt coronary artery disease or other conditions at risk consistently confirmed the association between moderate hyperhomocysteinemia and cardiovascular morbidity and mortality. More recently, an association between moderate hyperhomocysteinemia and heightened risk of venous thromboembolism has been documented, suggesting that hyperhomocysteinemia might be involved not only in atherogenesis, but also in thrombogenesis. The mechanisms by which hyperhomocysteinemia might contribute to atherogenesis and thrombogenesis are incompletely understood. The mainstay of treatment of hyperhomocysteinemia is folic acid, alone or in combination with vitamin B12 and vitamin B6. Although it is quite clear that vitamins effectively reduce the plasma levels of total homocysteine (tHcy), we do not yet know whether they will decrease the risk of vascular disease. The results of ongoing randomized, placebo‐controlled, double‐blind trials of the effects of vitamins on the thrombotic risk will help ir, defining whether the relationship between hyperhomocysteinemia and thrombosis is causal, and will potentially have a dramatic effect in the prevention of thromboembolic events.
The Hordaland Homocysteine Studies
Authors: Ueland Per Magne , Nygård Ottar , Vollset Stein Emil , Refsum Helga 
Published: November 2006

AbstractThe Hordaland Homocysteine Study is a population‐based screening of total plasma homocysteine (tHcy) in ∼18,000 men and women aged 40–67 yr that took place in 1992–1993 in the county of Hordaland in Western Norway. In this cohort, tHcy was associated with several physiologic and life‐style factors, including age and gender, blood pressure, serum cholesterol, smoking, alcohol and coffe consumption, physical activity, diet, and vitamin status. All associations with established cardiovascular risk factors were in the direction expected to confer increased risk. In a subset of 5,883 women aged 40–42 yr, tHcy was associated with previous pregnancy outcomes, including preeclampsia, placental abruption, and neural tube defects. This article reviews the published results from the Hordaland Homocysteine Study in the light of relevant literature. The Hordaland Homocysteine cohort will be used for future investigations of the stability of tHcy and vitamin status over time, and to investigate associations with mortality and morbidity including cancer incidence.
Marine n‐3 fatty acids: Basic features and background
Authors: Schmidt Erik Berg , Christensen Jeppe Hagstrup , Aardestrup Inge , Madsen Trine , Riahi Sam , Hansen Vibeke Ellegaard , Skou Helle Aarup 
Published: November 2006

AbstractThere is some evidence from epidemiology that intake of n‐3 polyunsaturated fatty acids (PUFA) from seafood may protect against coronary artery disease (CAD). This hypothesis is further supported from animal data showing a beneficial effect of n‐3 PUFA on thrombosis and atherosclerosis in animals fed fish oils in most, but not all, studies. There are several mechanisms by which an increased intake of marine n‐3 PUFA may protect against CAD; the most universal finding is a reduction of plasma triglycerides. It is puzzling, however, that a very low amount of n‐3 PUFA, with no known beneficial biochemical effects, seems to be cardioprotective. It has therefore been of paramount interest to perform clinical trials. Such evidence and trials are discussed in later chapters, and the results have been very encouraging.
n−3 polyunsaturated fatty acids and coronary thrombosis
Authors: Kristensen S. D. , Bach Iversen A. M. , Schmidt E. B. 
Published: November 2006

AbstractStudies of Greenland Eskimos showed that a very high intake of marine n−3 fatty acids markedly inhibited platelet reactivity and suggested that intake of these fatty acids might prevent coronary thrombosis. Later studies with lower, more practical doses of n−3 fatty acids also have shown a platelet inhibitory effect of n−3 fatty acids, albeit fairly marginal. Furthermore, n−3 fatty acids have little effect on measures of blood coagulability and may slightly decrease fibrinolysis. In animal models, n−3 fatty acids often have been shown to inhibit thrombosis, but again the doses have tended to be very high. Finally, there has been little effect of (low‐dose) n−3 fatty acids in clinical trials in humans on the incidence of myocardial infarction. Overall, there is little evidence for a major antithrombotic effect of practical doses of n−3 fatty acids on coronary thrombosis. This does not exclude a beneficial effect of n−3 fatty acids on coronary heart disease as suggested from clinical trials, but the major effect may be antiarrhythmic rather than antithrombotic.
n−3 fatty acids and revascularization procedures
Authors: Arnesen Harald 
Published: November 2006

AbstractLargely initiated by studies among Greenland Eskimos in the early 1970s, great attention has been given to the possible effects of the very long chain n−3 polyunsaturated fatty acids (PUFA) in a variety of cardiovascular disease states. A series of possibly positive effects on pathogenetic mechanisms in cardiovascular disease has evolved from laboratory studies in cell cultures and animals as well as in humans, focusing mainly on eicosanoid metabolism with reduced activities of platelets and leucocytes, reduced plasma triglycerides and, antiarrhythmic effects in the myocardium. A rationale for a positive effect of very long chain n−3 PUFA in the secondary prophylaxis after revascularization procedures obviously also exists. The positive clinical effects based on prospectively randomized trials are summarized as follows. After coronary artery bypass grafting (CABG), the SHOT study showed statistically significant reduction in angiographic vein graft occlusion in 610 patients after 1 yr with supplementation of 3.4 g/d of highly concentrated very long chain n−3 PUFA. The reduction in occlusion rates was significantly related to the change in the n−3 PUFA concentration in serum phospholipids during the study period with the occlusion rate in the upper quartile of such changes at only ∼50% of that in the lower quartile. These results were also clearly related to the presence of angina pectoris and occurrence of myocardial infarction after 1 yr. Several studies were conducted in patients after percutaneous transluminal coronary angioplasty (PTCA). By 1993, two meta‐analyses indicated a positive effect on the restenosis rate, a significant problem after otherwise successful PTCA. During the late 1990s, three large prospective randomized placebo‐controlled angiographic studies were conducted with very long n−3 PUFA 5.1–8.0 g/d, all with completely negative results. Today, therefore, very long chain n−3 PUFA supplementation cannot be recommended to reduce the incidence of restenosis after PTCA. All studies were performed without stenting of the coronary lesion. In the very special revascularization procedure of heart transplantation, evolving hypertension and accelerated atherosclerosis have been major clinical problems. In other studies, positive effects by supplementation with very long chain n−3 PUFA (3.4–5.7 g/d) were obtained on the surrogate end points coronary vasoreactivity to acetylcholine and hypertension, respectively. On the basis of the presently available literature from clinical studies, recommendations for supplementation with very long chain n−3 PUFA can be given to patients after venous CABG (up to 3.4 g/d), and after heart transplantation (3.4–5.7 g/d) but not to patients after traditional PTCA. In fact, data from substudies suggested the possibility that large doses (5.1 g/d) of very long chain n−3 PUFA might be contraindicated because they induce a proinflammatory state in patients under oxidative stress.
n−3 fatty acids, heart rate variability, and sudden cardiac death
Authors: Christensen Jeppe Hagstrup , Schmidt Erik Berg 
Published: November 2006

AbstractSudden cardiac death (SCD) is a major cause of mortality in Western countries. Furthermore, SCD is often the first manifestation of coronary artery disease, making it difficult to prevent. Heart rate variability (HRV), which can be determined by extended recording of the heart rate by 24‐h Holter monitoring, has been shown to be one of the best predictors of the risk of SCD. There is increasing evidence from animal experiments and clinical trials in humans that n−3 fatty acids reduce the risk of SCD. We have studied the effect of n−3 fatty acids on HRV and present data clearly showing that n−3 fatty acids increase HRV. This adds further to the hypothesis that an increased intake of n−3 fatty acids may reduce the risk of SCD.