bluuebunny/crossref_metadata_2025 huggingface dataset:
A chemometric study of active parameters and their interaction effects in a nebulized sheath‐liquid electrospray interface for capillary electrophoresis‐mass spectrometry
Authors: Nilsson Sara L. , Bylund Dan , Jörntén‐Karlsson Magnus , Petersson Patrik , Markides Karin E.
Published: June 2004

A chemometrics approach has been used for evaluating the effect of four experimental parameters when coupling capillary electrophoresis (CE) to electrospray ionization‐mass spectrometry (ESI‐MS). Electrospray voltage, sheath‐liquid flow rate, nebulizing gas flow rate, and spray needle position in respect to the MS orifice were varied according to a full factorial design. In addition to main effects, two interaction effects could be identified as significant when measuring the peak intensity of the analytes, from a sample mixture containing peptides and pharmaceuticals. The first interaction effects, between the nebulizing gas flow rate and the sheath‐liquid flow rate, and the second interaction effect, between the nebulizing gas flow rate and the spray position, could further explain the impact that these variables have on the spray performance. The number of theoretical plates and the baseline noise were also measured. The sheath‐liquid flow was found to significantly affect the separation efficiency, while the noise level mainly was controlled by the nebulizing gas flow. The same factorial design was also used for a CE capillary with lower internal diameter (ID) and the effects of the same variables were compared on those capillaries using equal injection volume for both capillaries. Similar trends were obtained in both capillaries but capillary ID was shown to be a significant variable when evaluating both capillaries in a single model. It was found that a capillary with 25 μm ID provided improved CE‐MS performance over than corresponding 50 μm ID capillary. Enhanced sensitivity was obtained using the narrow‐bore capillary, and at lower sheath‐liquid flow rate the 25 μm ID capillary also gave rise to more efficient peaks.
Platinum metallodrug‐protein binding studies by capillary electrophoresis‐inductively coupled plasma‐mass spectrometry: Characterization of interactions between Pt(II) complexes and human serum albumin
Authors: Timerbaev Andrei R. , Aleksenko Svetlana S. , Polec‐Pawlak Kasia , Ruzik Rafal , Semenova Olga , Hartinger Christian G. , Oszwaldowski Slawomir , Galanski1 Mathea Sophia , Jarosz Maciej , Keppler Bernhard K.
Published: June 2004

Characterizing how platinum metallocomplexes bind to human serum albumin (HSA) is essential in evaluating anticancer drug candidates. Using cisplatin as a reference complex, the application of capillary electrophoresis (CE) to reliably assess drug/HSA interactions was validated. Since this complex is small compared to the size of the protein, the binding response could only be recognized when applying CE coupled to a (platinum) metal‐specific mode of detection, namely inductively coupled plasma‐mass spectrometry (ICP‐MS). This coupling allowed for confirmation of a specific affinity of cisplatin and novel Pt complexes to HSA, measurement of the kinetics of binding reactions, and determination of the number of drug molecules attached to the protein. As the cisplatin/HSA molar ratio increased, the reaction rate became faster with a maximum on the kinetic curve appearing at about 50 h of incubation at 20 times excess of cisplatin. The reaction was characterized as a pseudo‐first order reaction with the rate constant k = 0.003 min−1 at 37°C. When incubated with a 20‐fold excess of cisplatin, HSA bound up to 10 mol of Pt per mol of the protein. This is indicative for a strong metal‐protein coordination occurring at several HSA sites other than the only protein cysteine residue. Structural analogs of cisplatin, bearing aminoalcohol ligands, showed comparable protein binding reactivity and stoichiometry but a common equilibrium was not reached even after one week of incubation. Also apparent was a two‐step mechanism of the binding reaction. Results demonstrated the suitability of CE‐ICP‐MS as a rapid assay for high‐throughput studying of drug/HSA interactions.
Highly sensitive analysis of multiple pesticides in foods combining solid‐phase microextraction, capillary electrophoresis‐mass spectrometry, and chemometrics
Authors: Hernández‐Borges Javier , Rodríguez‐Delgado Miguel Á. , García‐Montelongo Francisco J. , Cifuentes Alejandro
Published: June 2004

A highly sensitive procedure to detect multiple pesticides at trace levels in foods is presented. Initially a comparative study between capillary electrophoresis (CE)‐UV and CE‐mass spectrometry (MS) is carried out analyzing five pesticides not studied up to now (pyrimethanil, pyrifenox, cyprodinil, cyromazine, and pirimicarb). The comparison between CE‐UV and CE‐MS is established in terms of separation efficiency, speed of analysis, reproducibility, and sensitivity. A good separation of these compounds is achieved by both techniques using a volatile aqueous buffer containing 0.3 M ammonium acetate/acetic acid at pH 4. Time analysis reproducibility is studied for the same day (n = 5) and three different days (n = 15), showing no significant differences between CE‐UV and CE‐MS. The study on peak areas reproducibility shows a slightly worse reproducibility for CE‐MS compared with CE‐UV. The best limit of detection (LOD) that can be achieved for these pesticides using CE‐UV was 0.6 μg/mL. CE‐MS provides LODs one order of magnitude better than CE‐UV. Chemometrics are used to optimize the multiple parameters that play a role in solid‐phase microextraction (SPME) and CE‐MS analysis (e.g., extraction and desorption times, nebulizer pressure, dry gas flow, dry gas temperature, percentage of organic solvent and acid in the sheath liquid, etc.). The combined use of chemometrics and SPME‐CE‐MS clearly improves the LODs that can be achieved allowing the detection of pesticides at concentrations down to 15 ng/mL. The usefulness of this approach is demonstrated detecting multiple pesticides in different food samples as grapes and orange juice in a single run. The concentrations detected are below the maximum residue limits (MRLs) permitted for these pesticides in foods corroborating the value of our approach. This work demonstrates, to our knowledge for the first time, the good possibilities of the combined use of SPME‐CE‐MS and chemometrics.
Two‐dimensional liquid chromatography‐capillary zone electrophoresis‐sheathless electrospray ionization‐mass spectrometry: Evaluation for peptide analysis and protein identification
Authors: Janini George M. , Chan King C. , Conrads Thomas P. , Issaq Haleem J. , Veenstra Timothy D.
Published: June 2004

A peptide separation strategy that combines two‐dimensional (2‐D) liquid chromatography (LC)‐capillary zone electrophoresis (CZE) with tandem mass spectrometry (MS/MS) is described for the identification of proteins in complex mixtures. To test the effectiveness of this strategy, a serum sample was depleted of the high‐abundance proteins by methanol precipitation, digested with trypsin to generate a complex peptide mixture, and separated into 96 fractions by reversed‐phase (RP)‐LC. Compared to ion‐exchange LC separations, RPLC provides much higher resolution and peak capacity. Fractions were collected off‐line from the RPLC separation, and subjected to short 20 min CZE separations. The separated zones were introduced to the mass spectrometer through a sheathless electrospray ionization interface that is integrated on the separation capillary. The ease of fabrication of the interface and its durability allowed for the analysis of all fractions on a single capillary in a relatively short analysis time. A stable electrospray was produced at nanoliter flowrates by augmenting analyte electrophoretic and electroosmotic mobilities with pressure‐assisted flow. Unlike first‐dimensional ion‐exchange LC fractionation, where there is a large degree of overlap, the CZE‐MS results show less than 15% overlap between neighboring RPLC fractions.
Detection of Amadori compounds by capillary electrophoresis coupled to tandem mass spectrometry
Authors: Hau Jörg , Devaud Stéphanie , Blank Imre
Published: June 2004

Capillary electrophoresis coupled to mass spectrometry (CE‐MS) is reported for the first time as an alternative and powerful analytical method for the characterization and monitoring of N‐substituted 1‐amino‐1‐deoxyketoses (Amadori compounds). It allows rapid separation and identification of Amadori compounds, while benefiting from the well‐known advantages of MS, such as specificity and sensitivity. Amadori compounds of several amino acids, such as glycine, valine, isoleucine, methionine, proline, and phenylalanine, as well as a cysteine‐derived compound, were separated and/or discriminated using CE‐MS/MS under standard conditions. The technique may also be useful to study the stability and degradation kinetics of other labile charged Maillard intermediates that play an important role in food and medical science.
Pricing options using implied trees: Evidence from FTSE‐100 options
Authors: Lim Kian Guan , Zhi Da
Published: June 2004

Previously, few, if any, comparative tests of performance of Jackwerth's (1997) generalized binomial tree (GBT) and Derman and Kani (1994) implied volatility tree (IVT) models were done. In this paper, we
propose five different weight functions in GBT and test them empirically compared to both the
Black‐Scholes model and IVT.

We use the daily settlement prices of FTSE‐100 index options from January to November 1999. With both
American and European options traded on the FTSE‐100 index, we construct both GBT and IVT from European
options and examine their performance in both the hedging of European option and the pricing of its American
counterpart. IVT is found to produce least hedging errors and best results for American call options with earlier
maturity than the maturity span of the implied trees. GBT appears to produce better results for American ATM put
pricing for any maturity, and better in‐sample fit for options with maturity equal to the maturity span of
the implied trees. Deltas calculated from IVT are consistently lower (higher) than Black‐Scholes
deltas for both European and American calls (puts) in absolute term. The reverse holds true for GBT
deltas. These empirical findings about the relative performance of GBT, IVT, and Standard Black‐Scholes
models are important to practitioners as they indicate that different methods should be used for different
applications, and some cautions should be exercised. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark
22:601–626, 2002
What moves German Bund futures contracts on the Eurex?
Authors: Ahn Hee‐Joon , Cai Jun , Cheung Yan‐Leung
Published: June 2004

The German 10‐year Bund futures contract traded on the Eurex futures and options exchange in Frankfurt
became the world's most actively traded derivative product by the end of 1999. In this article, we provide a
detailed exploration of the interday and intraday return volatility in the Bund futures contract using a sample of
five‐min returns from 1997 to 1998. The evolution of interday volatility is described best by a
MA(1)‐fractionally integrated process that allows for the long‐memory features. At the
intraday level, we find that macroeconomic announcements from both Germany and the U.S. are an important source of
volatility. Among the various German announcements, we identify the IFO industry survey of business climate,
industrial production (preliminary), and Bundesbank policy meeting as being by far the most important.
The three most significant U.S. announcements include the employment report, the National Association of
Purchasing Managers (NAPM) survey, and employment costs. Overall, U.S. macroeconomic announcements have
a far greater impact on the Bund futures market than their German counterparts. © 2002 Wiley Periodicals,
Inc. Jrl Fut Mark 22:679–696, 2002
Transformations of the American College Ideal: Six Historic Ways of Learning
Authors: Goodchild Lester F.
Published: June 2004

Six historic ways of learning provide a framework for understanding the American collegiate ideal. A comprehensive vision of the collegiate ideal for the twenty‐first century is still lacking.
The Diverse Campus: Broadening Our Ideal to Incorporate All Voices
Authors: Kezar Adrianna J.
Published: June 2004

While often considered an elitist concept, the collegiate ideal has changed over time to become a more pluralistic model with benefits for diverse students.
Developing the Whole Student: The Collegiate Ideal
Authors: Wolf‐Wendel Lisa E. , Ruel Marti
Published: June 2004

Traditional models for developing the whole student no longer serve the diverse population currently pursuing higher education. A new philosophy that focuses on the partnership between student affairs professionals and faculty is necessary to further student development.
The Student Affairs Establishment and the Institutionalization of the Collegiate Ideal
Authors: Ortiz Anna M.
Published: June 2004

The traditional collegiate ideal is institutionalized on many campuses through the structure and the types of services offered by student affairs units. In order to change the collegiate ideal to represent a more inclusive environment, student affairs professionals must examine their policies and procedures and make changes that will help meet the developmental needs of nontraditional students.
Faculty Culture and College Life: Reshaping Incentives Toward Student Outcomes
Authors: Amey Marilyn J.
Published: June 2004

Faculty incentives are skewed away from the collegiate ideal, particularly at research universities. Is it inevitable that reasearch‐oriented faculty divorce themselves from campus life, or can the incentive system be reshaped to incorporate faculty contributions to campus life?
Vocational Education and the Collegiate Ideal: The Threat and the Challenge of Limited Resources
Authors: Hagedorn Linda Serra
Published: June 2004

Although fiscal restraints have impacted all levels of postsecondary education, community college vocational programs have been particularly hard hit. This chapter presents a thorough examination of present conditions, challenges the vision of “place,” and provides a realistic approach toward the “ideal” within vocational education community college programs.
The Collegiate Ideal in the Twenty‐First Century
Authors: Chickering Arthur W. , Kytle Jackson
Published: June 2004

Whatever forms they take, the colleges of the twenty‐first century must incorporate educational fundamentals underlying traditional residential institutions.
Library Cooperation
Authors: Wylie Neil R. , Yeager Tamara L.
Published: June 2004

Library cooperation is described in two consortia with extensive library programs; various ways college and university libraries can work together to enhance library access and share resources are suggested.
Faculty Development: Working Together to Improve Teaching and Learning
Authors: Dotolo Lawrence G.
Published: June 2004

The evolution of a consortial faculty development program and the important factors necessary to have a successful program are discussed.
Consortial Fundraising
Authors: Peterson Lorna M.
Published: June 2004

More and more foundations, both private and public, are encouraging institutions of higher education to work together, even in their fundraising efforts.
Cooperation for Cost‐Effectiveness in Purchasing
Authors: Dorger Mitch
Published: June 2004

One way to approach cost control is by taking advantage of cooperative activities with other, similar institutions.
Statewide Consortia for the Use of Technology
Authors: Widmayer Patricia
Published: June 2004

Consortia are pivotal vehicles with which colleges and universities, schools, museums, and libraries can acquire advanced technology for teaching, learning, research, and administration.
Technology, Consortia, and the Relationship Revolution in Education
Authors: Godbey Galen C. , Richter Gerald J.
Published: June 2004

Educational consortia are joining the rush to obtain new telecommunications and learning technologies, which must be adopted within a paradigm of organizational agility.
Economic Development and Consortia
Authors: Watson Allan , Jordan Linda
Published: June 2004

Examples of workforce training and education projects that support regional economic development are outlined to demonstrate successful business–higher education collaboration.
Annotated Bibliography
Authors: Dotolo Lawrence G. , Strandness Jean T.
Published: June 2004

The works represented in this selected bibliography together discuss the major historical and contemporary issues and themes pertinent to interinstitutional collaboration and consortia.
What You Need to Know About Enrollment Management
Authors: Lapovsky Lucie
Published: June 2004

The chief financial officer cannot avoid playing a role in the decisions involved in enrollment management.
Investment Policies for College and University Endowments
Authors: Spitz William T.
Published: June 2004

The chief financial officer needs to pursue policies that will assure both income and stability.
Identifying and Managing Risk
Authors: Abraham Janice M.
Published: June 2004

The buildings, people, and mission of an institution are inevitably exposed to risks that must be concerns of the chief financial officer.
Financing Participation in Consortia
Authors: Maydew Mary Jo
Published: June 2004

Cooperation can help deal with problems of competitiveness.
Higher Education Funding Formulas
Authors: McKeown‐Moak Mary P.
Published: June 2004

Funding formulas introduce additional dimensions into an institution's budget planning.
Effective Admissions Recruitment
Authors: Hossler Don
Published: June 2004

As higher education searches for new technological methods, it should not overlook traditional methods of recruitment.
Modeled Retention and Graduation Rates: Calculating Expected Retention and Graduation Rates for Multicampus University Systems
Authors: Blose Gary
Published: June 2004

The State University of New York, using large databases and regression techniques, has developed several coordinated, comprehensive efforts to evaluate and project current and future enrollments.
Developmental and Remedial Education in Postsecondary Education
Authors: Boylan Hunter R. , Bonham Barbara S. , White Stephen R.
Published: June 2004

There are proven techniques to successfully address the thorny issues of developmental and remedial education efforts.
What the Future Holds
Authors: Gaither Gerald H.
Published: June 2004

Facing large demographic changes, conflicting philosophies toward access, and more costly remediation efforts, the university of the future will need to reform its mission as well as its labor‐intensive approach to avoid a political backlash.
Curricular Learning Communities
Authors: Levine Jodi H. , Shapiro Nancy S.
Published: June 2004

Curricular learning communities help students overcome the sense of fragmentation of course work and isolation from faculty and peers.
Creating Community Within Individual Courses
Authors: Chickering Arthur W.
Published: June 2004

Faculty can increase commuter students' involvement in learning by creating community within their classes.
Developing Community Through Experiential Education
Authors: Rubin Sharon
Published: June 2004

Experiential education offers opportunities for students to work collaboratively with peers and to engage with others in reflection to achieve desired learning outcomes.
The Tyranny of Success: The Research‐Practice Tension
Authors: Peterson Marvin W.
Published: June 2004

As higher education has emerged into a recognized professional field, tensions have grown around the competing demands of theory, research, and practice.
To Be More Useful: Embracing Interdisciplinary Scholarship and Dialogue
Authors: Conrad Clifton F. , Gunter Ramona
Published: June 2004

A learning community that involves all the stakeholders—policymakers, faculty, administrators, and academic leaders—is an avenue for moving beyond the research‐practice gap.
Change as a Scholarly Act: Higher Education Research Transfer to Practice
Authors: Ramaley Judith A.
Published: June 2004

Good campus decision making begins with a base of scholarly knowledge that is generated by higher education researchers and is ideally modeled by higher education leaders who practice public learning.
Bridging the Gap: Multiple Players, Multiple Approaches
Authors: Green Madeleine F.
Published: June 2004

After reviewing the suggestions discussed in the previous chapters, this chapter discusses how national organizations can serve as change agents to bridge the research‐practice gap.
Midlevel Administrators: What We Know
Authors: Rosser Vicki J.
Published: June 2004

Midlevel administrators are committed and well trained and adhere to high standards of performance and excellence in their areas of expertise.
Academic Advising
Authors: Tuttle Kathryn Nemeth
Published: June 2004

Because retention improves the academic foundation of the institution, most colleges and universities have approved the expansion of advising centers in the last twenty years.
Information Technology
Authors: Lassner David
Published: June 2004

Information technology pervades every aspect of the institutional mission: instruction, scholarship, research, service, and economic development.
Human Resources
Authors: Julius Daniel J.
Published: June 2004

This chapter describes the typical functional areas of human resources in most colleges and universities and profiles issues attendant to the development and success of human resource administrators.
International Student Affairs
Authors: Wood Melinda , Kia Parandeh
Published: June 2004

Many institutions are keenly interested in internationalizing their campuses by making substantive commitment to various aspects of international education.
Budget and Planning
Authors: Haeuser Patricia N.
Published: June 2004

One of the important factors in effective planning is developing a method to align resources with plans.
Institutional Research
Authors: Olsen Deborah
Published: June 2004

Institutional research has solidified and enhanced its role within institutions of higher education and better articulated itself as a professional community.
Wisconsin Ideas: The Continuing Role of the University in the State and Beyond
Authors: Witte John F.
Published: June 2004

The emergence of public policy institutes at universities began with the Wisconsin idea. The program has continued to be a pioneer in its state, national, and international programs.
Building Partnerships with Governments: The Experience of the Lyndon B. Johnson School of Public Affairs
Authors: Sherman Max , Duncan Marilyn P.
Published: June 2004

The LBJ School offers extensive policy research projects to train students and to find solutions for local, national, and international problems.
The Reubin O'Donovan Askew Institute: Building Community in Florida
Authors: Colburn David R. , Leverty Lynn H.
Published: June 2004

A distinguishing purpose of this university policy institute is to foster civic engagement on a wide variety of local and state issues.
Hepatocellular telomere shortening correlates with chromosomal instability and the development of human hepatoma
Authors: Plentz Ruben R. , Caselitz Martin , Bleck Joerg S. , Gebel Michael , Flemming Peer , Kubicka Stefan , Manns Michael P. , Rudolph Lenhard K.
Published: June 2004

The telomere hypothesis of cancer initiation indicates that telomere shortening initiates cancer by induction of chromosomal instability. To test whether this hypothesis applies to human hepatocellular carcinoma (HCC), we analyzed the telomere length of hepatocytes in cytological smears of fine-needle biopsies of liver tumors from patients with cirrhosis (n = 39). The tumors consisted of 24 HCC and 15 regenerative nodules as diagnosed by combined histological and cytological diagnostics. In addition, we analyzed the telomere length of hepatocytes in HCC and surrounding noncancerous liver tissue within individual patients in another cohort of 10 patients with cirrhosis. Telomere length analysis of hepatocytes was correlated with tumor pathology and ploidy grade of the tumors, which was analyzed by cytophotometry. Telomeres were significantly shortened in hepatocytes of HCC compared to hepatocytes in regenerative nodules or surrounding noncancerous liver tissue. Hepatocyte telomere shortening in HCC was independent of the patient’s age. There was no overlap in mean telomere lengths of individual samples when comparing HCC with regenerative nodules or noncancerous surrounding liver. Within the HCC group, telomeres were significantly shorter in hepatocytes of aneuploid tumors compared to diploid tumors. In conclusion, our data suggest that the telomere hypothesis of cancer initiation applies to human HCC and that cell type-specific telomere length analysis might indicate the risk of HCC development. (Hepatology 2004;40:80-86.)
Beyond insulin resistance in NASH: TNF-α or adiponectin?
Authors: Hui Jason M. , Hodge Alex , Farrell Geoffrey C. , Kench James G. , Kriketos Adamandia , George Jacob
Published: June 2004

Adiponectin has antilipogenic and anti-inflammatory effects, while tumor necrosis factor α (TNF-α) reduces insulin sensitivity and has proinflammatory effects. We examined (1) the extent to which hypoadiponectinemia and TNF-α activation are features of nonalcoholic steatohepatitis (NASH) and (2) whether serum levels of these markers correlate with the severity of histological changes in 109 subjects with nonalcoholic fatty liver disease (NAFLD), including 80 with NASH and 29 with simple steatosis. By multivariate analysis, subjects with NASH had reduced adiponectin level and increased TNF-α and soluble TNF receptor 2 (sTNFR2)—but not leptin levels, compared with controls matched by age, sex, and body mass index; these differences were independent of the increased insulin resistance (by homeostasis model [HOMA-IR]) in NASH. When compared with simple steatosis, NASH was associated with lower adiponectin levels and higher HOMA-IR, but there were no significant differences in the levels of TNF-α and sTNFR2. The majority of subjects with steatohepatitis (77%) had adiponectin levels less than 10 μg/mL and HOMA-IR greater than 3 units, but only 33% of those with pure steatosis had these findings. HOMA-IR and low serum adiponectin were also independently associated with increased grades of hepatic necroinflammation. In conclusion, hypoadiponectinemia is a feature of NASH independent of insulin resistance. Reduced adiponectin level is associated with more extensive necroinflammation and may contribute to the development of necroinflammatory forms of NAFLD. (Hepatology 2004;40:46-54.)
Ligation versus propranolol for the primary prophylaxis of variceal bleeding in cirrhosis†
Authors: Schepke Michael , Kleber Gerhard , Nürnberg Dieter , Willert Jörg , Koch Lydia , Veltzke-Schlieker Wilfried , Hellerbrand Claus , Kuth Johannes , Schanz Stefan , Kahl Stefan , Fleig Wolfgang E. , Sauerbruch Tilman
Published: June 2004

In this randomized controlled multicenter trial, we compared endoscopic variceal banding ligation (VBL) with propranolol (PPL) for primary prophylaxis of variceal bleeding. One hundred fifty-two cirrhotic patients with 2 or more esophageal varices (diameter >5 mm) without prior bleeding were randomized to VBL (n = 75) or PPL (n = 77). The groups were well matched with respect to baseline characteristics (age 56 ± 10 years, alcoholic etiology 51%, Child-Pugh score 7.2 ± 1.8). The mean follow-up was 34 ± 19 months. Data were analyzed on an intention-to-treat basis. Neither bleeding incidence nor mortality differed significantly between the 2 groups. Variceal bleeding occurred in 25% of the VBL group and in 29% of the PPL group. The actuarial risks of bleeding after 2 years were 20% (VBL) and 18% (PPL). Fatal bleeding was observed in 12% (VBL) and 10% (PPL). It was associated with the ligation procedure in 2 patients (2.6%). Overall mortality was 45% (VBL) and 43% (PPL) with the 2-year actuarial risks being 28% (VBL) and 22% (PPL). 25% of patients withdrew from PPL treatment, 16% due to side effects. In conclusion, VBL and PPL were similarly effective for primary prophylaxis of variceal bleeding. VBL should be offered to patients who are not candidates for long-term PPL treatment. (Hepatology 2004;40:65-72.)
Cost-minimization analysis of MRC versus ERCP for the diagnosis of primary sclerosing cholangitis
Authors: Talwalkar Jayant A. , Angulo Paul , Johnson Daniel C. , Petersen Bret T. , Lindor Keith D.
Published: June 2004

Investigations examining the use of magnetic resonance cholangiography (MRC) for the diagnosis of primary sclerosing cholangitis (PSC) have described comparable accuracy when compared to endoscopic retrograde cholangiopancreatography (ERCP). The effectiveness of MRC based on overall cost, however, remains unknown. Our aim was to determine the average cost per correct diagnosis using MRC or ERCP as the initial testing strategy for the diagnosis of PSC. A decision analysis model was constructed employing diagnostic test parameters prospectively determined among 73 patients with clinically suspected biliary disease. ERCP was performed within 24 hours after MRC. Cost data were derived from average Medicare reimbursement fee schedules. The prevalence of PSC in the study cohort was 32%. The sensitivity and specificity of MRC for the diagnosis of PSC were 82% and 98%, respectively. The average cost per correct diagnosis of PSC was $724.00 for initial MRC (including the cost of ERCP following a negative MRC examination) versus $793.17 for initial ERCP. In the absence of biliary obstruction, the average cost per correct diagnosis of PSC was $549.64 with MRC versus $623.25 for ERCP. The average cost of managing post-ERCP-related complications among patients with PSC was $2902.20 (range, $1915.40-$5031.54). For ERCP to be the optimal initial test strategy, a prevalence rate of PSC greater than 45%, MRC specificity less than 85%, or reduction in the average cost per diagnosis to $538.30 would be required. In conclusion, MRC has comparable accuracy to ERCP and results in cost savings when used as the initial test strategy for diagnosing PSC. (Hepatology 2004;40:39-45.)
Acetaminophen and the U.S. acute liver failure study group: Lowering the risks of hepatic failure
Authors: Lee William M.
Published: June 2004

Acetaminophen overdose is the leading cause for calls to Poison Control Centers (>100,000/year) and accounts for more than 56,000 emergency room visits, 2,600 hospitalizations, and an estimated 458 deaths due to acute liver failure each year. Data from the U.S. Acute Liver Failure Study Group registry of more than 700 patients with acute liver failure across the United States implicates acetaminophen poisoning in nearly 50% of all acute liver failure in this country. Available in many single or combination products, acetaminophen produces more than $1 billion dollars in annual sales for Tylenol products alone. It is heavily marketed for its safety compared to nonsteroidal analgesics. By enabling self-diagnosis and treatment of minor aches and pains, its benefits are said by the Food and Drug Administration to outweigh its risks. It still must be asked: Is this amount of injury and death really acceptable for an over-the-counter pain reliever? (Hepatology 2004;40:6-9.)
Acetaminophen misconceptions
Authors: Rumack Barry H.
Published: June 2004

Examination of the pharmacokinetics of acetaminophen can decrease misconceptions involved in clinical evaluation. Enzyme patterns and acetaminophen levels must be related to time and known metabolic phenomena. A careful look at ethanol and nutrition, especially fasting demonstrates that therapeutic doses of acetaminophen do not place patients at a greater risk in either of these instances. An overdose of acetaminophen in a chronic alcohol abuser may result in more severe hepatotoxicity than in the nonalcoholic. CYP2E1 and glutathione must be evaluated simultaneously rather than in isolation. Glucuronidation capacity in humans is not a factor except in massively overdosed patients. (Hepatology 2004;40:10-15.)
Characterizing the spatial variability of groundwater quality using the entropy theory: II. Case study from Gaza Strip
Authors: Mogheir Y. , de Lima J. L. M. P. , Singh V. P.
Published: June 2004

This paper, the second in the series, uses the entropy theory to describe the spatial variability of groundwater quality data sets. The application of the entropy theory is illustrated using the chloride observations obtained from a network of groundwater quality monitoring wells in the Gaza Strip, Palestine. The application involves calculating information measures, such as transinformation, the information transfer index and the correlation coefficient. These measures are calculated using a discrete approach, in which contingency tables are used. An exponential decay fitting approach was applied to the discrete models. The analysis shows that transinformation, as a function of distance, can be represented by the exponential decay curve. It also indicates that, for the data used in this study, the transinformation model is superior to the correlation model for characterizing the spatial variability. Copyright © 2004 John Wiley & Sons, Ltd.
Transient modelling of lacustrine regressions: two case studies from the Andean Altiplano
Authors: Condom Thomas , Coudrain Anne , Dezetter Alain , Brunstein Daniel , Delclaux François , Jean‐Emmanuel Sicart
Published: June 2004

A model was developed for estimating the delay between a change in climatic conditions and the corresponding fall of water level in large lakes. The input data include: rainfall, temperature, extraterrestrial radiation and astronomical mid‐month daylight hours. The model uses two empirical coefficients for computing the potential evaporation and one parameter for the soil capacity. The case studies are two subcatchments of the Altiplano (196 000 km2), in which the central low points are Lake Titicaca and a salar corresponding to the desiccation of the Tauca palaeolake. During the Holocene, the two catchments experienced a 100 m fall in water level corresponding to a decrease in water surface area of 3586 km2 and 55 000 km2, respectively. Under modern climatic conditions with a marked rainy season, the model allows simulation of water levels in good agreement with the observations: 3810 m a.s.l. for Lake Titicaca and lack of permanent wide ponds in the southern subcatchment. Simulations were carried out under different climatic conditions that might explain the Holocene fall in water level. Computed results show quite different behaviour for the two subcatchments. For the northern subcatchment, the time required for the 100 m fall in lake‐level ranges between 200 and 2000 years when, compared with the present conditions, (i) the rainfall is decreased by 15% (640 mm/year), or (ii) the temperature is increased by 5·5 °C, or (iii) rainfall is distributed equally over the year. For the southern subcatchment (Tauca palaeolake), the time required for a 100 m decrease in water level ranges between 50 and 100 years. This decrease requires precipitation values lower than 330 mm/year. Copyright © 2004 John Wiley & Sons, Ltd.
Suspended sediment and phosphorus in proglacial rivers: bioavailability and potential impacts upon the P status of ice‐marginal receiving waters
Authors: Hodson Andy , Mumford Paul , Lister Debbie
Published: June 2004

This paper adopts standard tests developed in temperate catchment research to determine the total phosphorus (TP) and the algal available (base‐extractable) phosphorus (NaOH–P) content of a wide range of glaciofluvial sediments from the Northern Hemisphere. We find that the TP content of these sediments is broadly similar to the P content of major rock types in Earth's crust (230–670 µgP/g) and so the TP yields of glacier basins may be high owing to the efficacy of suspended sediment evacuation by glacial meltwaters. We show that this is best achieved where subglacial drainage systems are present. The NaOH–P pool of the sediments is found to be low (1–23 µgP/g) relative to the TP pool and also to the NaOH–P pool of suspended sediments in temperate, non‐glacierized catchments. This most probably reflects the restricted duration of intimate contact between dilute meltwaters and glacial suspended sediments during the ablation season. Thus, despite the high surface‐area:volume ratio of glacial suspended sediments, the potential for P adsorption to mineral surfaces following release by dissolution is also low. Further, sorption experiments and sequential extraction tests conducted using glacial suspended sediments from two Svalbard catchments indicate that the generation of reactive secondary minerals (e.g. Fe‐ and other hydroxides) with a strong capacity to scavenge P from solution (and thereby promote the continued dissolution of P) may also be limited by the short residence times. Most P is therefore associated with poorly weathered, calcite/apatite‐rich mineral phases. However, we use examples from the Svalbard glacier basins (Austre Brøggerbreen and Midre Lovénbreen) to show that the high sediment yields of glaciers may result in appreciable NaOH–P loading of ice‐marginal receiving waters. Again, the importance of subglacial drainage is highlighted, as it produces a major, episodic release of NaOH–P at Midre Lovénbreen that results in a yield (8·2 kg NaOH–P/km2/year) more than one order of magnitude greater than that at Austre Brøggerbreen (where subglacial drainage is absent and the yield is 0·48 kg NaOH‐P/km2/year). Therefore, as since both detrimental and beneficial effects of sediment‐bound P loading in ice marginal receiving waters are possible (i.e. either reduced primary productivity owing to increased turbidity or P fertilization following desorption) there is a pressing need to assess the ambient P status of such environments and also the capacity for ice‐marginal ecosystems to adapt to such inputs. Copyright © 2004 John Wiley & Sons, Ltd.
Experimental investigation of bedload transport processes under unsteady flow conditions
Authors: Lee Kwan Tun , Liu Yi‐Liang , Cheng Kai‐Hung
Published: June 2004

Hydraulic engineering is usually based on theoretical analysis and/or numerical modelling simulation. As the dynamic behaviour of sediment movement under unsteady flow is still unclear, and field measurement is comparatively difficult during a large flood, prior investigations through flume experiments are required. A series of flume experiments, conducted using different inflow hydrographs without sediment supply from upstream, was carried out to investigate the sediment transport process under unsteady flow conditions.

A series of triangular hydrographs were performed in the experiments. The results indicate that a temporal lag was found between the flow hydrograph peak and the sediment hydrograph peak because large size sand dunes lasted for a short period in the falling limb of the flow hydrograph. The temporal lag was found to be about equal to 6–15% of the flow hydrograph duration. Owing to the temporal lag, the total bedload yield in the rising period was less than that in the falling period. Furthermore, the measured total bedload yield in the unsteady flow experiments was larger than the predicted value, which was estimated by using the results obtained from the equivalent steady flow experiment. The peak bedload transport rate for unsteady flow conditions was also larger than the predicted value. The ratios of the measured to the predicted quantities mentioned above were found to be constant values for different shapes of hydrographs. It is, therefore, expected that the analytical results of sediment transport from equivalent steady flow can be a good reference for sediment transport under unsteady flow conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Determination of two‐dimensional laboratory‐scale dispersivities
Authors: Kim Song‐Bae , Jo Kyu‐Hyeok , Kim Dong‐Ju , Jury William A.
Published: June 2004

A tracer test was conducted in a laboratory chamber representing a two‐dimensional aquifer to investigate the longitudinal dispersivity (αL) and the ratio (αT/αL) of transverse to longitudinal dispersivity of sandy aquifer materials. Dispersive parameters were obtained by matching the observed chloride plumes at 9 hours and 16 hours after tracer injection with those simulated by a flow and transport model. The best match was found for αL = 0·2 − 0·25 cm and αT/αL = 0·2. The ratio of αT/αL = 0·2 was within the range of laboratory values reported in the literature. Sensitivity analysis revealed that the tracer plume concentration and shape were more sensitive to variations in longitudinal dispersivity than to the ratio of transverse to longitudinal dispersivity. This result contrasted with findings of others, showing that the dispersivity ratio greatly affects contaminant plume shape. However, our experimental boundary conditions restricted expansion of the plume normal to the direction of flow and thus affected the parameter estimation. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling water infiltration in cracked paddy field soil
Authors: Liu Chen‐Wuing , Chen Shih‐Kai , Jang Cheng‐Shin
Published: June 2004

Periodic paddy field flooding is a major source of groundwater recharge. Many paddy fields thus are used as groundwater recharge ponds after harvesting the first crop of the summer. Following rice harvesting, paddy field surfaces may crack into fissures as a result of drainage and exposure to sunlight. Field observation indicates that applying precipitation to the paddy field can increase the rate of infiltration. To quantitatively evaluate the amount of infiltration in a cracked paddy field, this study sets up a simple soil crack model to simulate the field infiltration process. A three‐dimensional groundwater model FEMWATER is adopted to simulate water movement in the paddy field subjected to various crack conditions. Using the field and laboratory data of irrigation water requirements, soil physical properties, hydraulic conductivities and soil profiles obtained from Ten‐Chung, FEMWATER simulates the water movement in the dry cracked paddy. Simulation results show that if the cracks develop extensively and penetrate the ploughed soil, the infiltration rate may increase significantly. The infiltration fluxes of crack with depths of 80, 60 and 27·5 cm are 18·77, 14·50 and 8·06 times higher than that of 20 cm, respectively. The simulation results of cracks with 80 cm depth correlated closely with field observations. The results of the study elucidate the processes of unsaturated water movement in a dry cracked paddy field. Copyright © 2004 John Wiley & Sons, Ltd.
Techniques for assessing the climatic sensitivity of river flow regimes
Authors: Bower Donna , Hannah David M. , McGregor Glenn R.
Published: June 2004

Regimes are useful tools for characterizing the seasonal behaviour of river flow and other hydroclimatological variables over an annual cycle (hydrological year). This paper develops and tests: (i) a regime classification method to identify spatial and temporal patterns in intraannual hydroclimatological response; and (ii) a novel sensitivity index (SI) to assess river flow regimes' climatic sensitivity. The classification of regime shape (form) and magnitude considers the whole annual cycle rather than isolating a single month or season for analysis, which has been the common approach of previous studies. The classification method is particularly useful for identifying large‐scale patterns in regimes and their between‐year stability, thus providing a context for short‐term, small‐scale process‐based research. The SI provides a means of assessing the often‐complex linkages between climatic drivers and river flow, as it identifies the strength and direction of associations between classifications of climate and river flow regimes. The SI has the potential for application to other problems where relationships between nominal classifications require to be found. These techniques are evaluated by application to a test data set of river flow, air temperature and rainfall time‐series (1974–1999) for a sample of 35 UK river basins. The results support current knowledge about the hydroclimatology of the UK. Although this research does not seek to yield new, detailed physical process understanding, it provides perspective at large spatial and temporal scales upon climate and flow regime patterns and quantifies linkages. Having clearly demonstrated the regime classification and SI to be effective in an environment where the hydroclimatology is relatively well known, there appears to be much to gain from applying these techniques in parts of the world where patterns and associations between climate and hydrology are poorly understood. Copyright © 2004 John Wiley & Sons, Ltd.
Forecasting flows in Apalachicola River using neural networks
Authors: Huang Wenrui , Xu Bing , Chan‐Hilton Amy
Published: June 2004

Forecasting river flow is important to water resources management and planning. In this study, an artificial neural network (ANN) model was successfully developed to forecast river flow in Apalachicola River. The model used a feed‐forward, back‐propagation network structure with an optimized conjugated training algorithm. Using long‐term observations of rainfall and river flow during 1939–2000, the ANN model was satisfactorily trained and verified. Model predictions of river flow match well with the observations. The correlation coefficients between forecasting and observation for daily, monthly, quarterly and yearly flow forecasting are 0·98, 0·95, 0·91 and 0·83, respectively. Results of the forecasted flow rates from the ANN model were compared with those from a traditional autoregressive integrated moving average (ARIMA) forecasting model. Results indicate that the ANN model provides better accuracy in forecasting river flow than does the ARIMA model. Copyright © 2004 John Wiley & Sons, Ltd.
Using a topographic index to distribute variable source area runoff predicted with the SCS curve‐number equation
Authors: Lyon Steve W. , Walter M. Todd , Gérard‐Marchant Pierre , Steenhuis Tammo S.
Published: June 2004

Because the traditional Soil Conservation Service curve‐number (SCS‐CN) approach continues to be used ubiquitously in water quality models, new application methods are needed that are consistent with variable source area (VSA) hydrological processes in the landscape. We developed and tested a distributed approach for applying the traditional SCS‐CN equation to watersheds where VSA hydrology is a dominant process. Predicting the location of source areas is important for watershed planning because restricting potentially polluting activities from runoff source areas is fundamental to controlling non‐point‐source pollution. The method presented here used the traditional SCS‐CN approach to predict runoff volume and spatial extent of saturated areas and a topographic index, like that used in TOPMODEL, to distribute runoff source areas through watersheds. The resulting distributed CN–VSA method was applied to two subwatersheds of the Delaware basin in the Catskill Mountains region of New York State and one watershed in south‐eastern Australia to produce runoff‐probability maps. Observed saturated area locations in the watersheds agreed with the distributed CN–VSA method. Results showed good agreement with those obtained from the previously validated soil moisture routing (SMR) model. When compared with the traditional SCS‐CN method, the distributed CN–VSA method predicted a similar total volume of runoff, but vastly different locations of runoff generation. Thus, the distributed CN–VSA approach provides a physically based method that is simple enough to be incorporated into water quality models, and other tools that currently use the traditional SCS–CN method, while still adhering to the principles of VSA hydrology. Copyright © 2004 John Wiley & Sons, Ltd.