bluuebunny/crossref_metadata_2025 huggingface dataset:
Geochemical and isotopic evidence of a groundwater source in the Corral Canyon meadow complex, central Nevada, USA
Authors: Atekwana Eliot A. , Richardson Dorothea S.
Published: June 2004

Major inorganic ions and stable carbon and oxygen isotopes in stream water, groundwater, groundwater seeps and springs were measured in the Corral Canyon meadow complex and watershed in the Toquima Mountains of central Nevada, USA. The purpose of the study was to determine whether stream water or groundwater was the source of water that supports vegetation in the meadow complex. Water samples from the watershed and meadow complex were mixed cation–HCO3 type. Stream water sampled at different locations in the meadow complex showed variations in temperature, pH and specific conductance. The cation–anion proportions for stream water were similar to groundwater, groundwater seeps and runoff from the meadow complex. Stable oxygen isotope ratios for stream water (−17·1 to −17·6‰ versus VSMOW) and groundwater and groundwater seeps in the meadow site (−17·0 to −17·7‰ versus VSMOW) were similar, and consistent with a local meteoric origin. Dissolved inorganic carbon (DIC) and the δ 13CDIC for stream water (−12·1 to −15·0‰ versus VPDB) were different from that of groundwater from the meadow complex (−15·3 to −19·9‰ versus VPDB), suggesting different carbon evolution pathways. However, a simple model based on cation–δ 13CDIC suggests that stream water was being recharged by shallow groundwater, groundwater seeps and runoff from the meadow complex. This leads to the conclusion that the source of water that supports vegetation in the meadow complex was primarily groundwater. The results of this study suggest that multiple chemical and stable carbon isotope tracers are useful in determining the source of water that supports vegetation in meadow complexes in small alpine watersheds. Copyright © 2004 John Wiley & Sons, Ltd.
Sensitivity to acidification of subalpine ponds and lakes in north‐western Colorado
Authors: Campbell D. H. , Muths E. , Turk J. T. , Corn P. S.
Published: June 2004

Although acidifying deposition in western North America is lower than in many parts of the world, many high‐elevation ecosystems there are extremely sensitive to acidification. Previous studies determined that the Mount Zirkel Wilderness Area (MZWA) has the most acidic snowpack and aquatic ecosystems that are among the most sensitive in the region. In this study, spatial and temporal variability of ponds and lakes in and near the MZWA were examined to determine their sensitivity to acidification and the effects of acidic deposition during and after snowmelt. Within the areas identified as sensitive to acidification based on bedrock types, there was substantial variability in acid‐neutralizing capacity (ANC), which was related to differences in hydrological flowpaths that control delivery of weathering products to surface waters. Geological and topographic maps were of limited use in predicting acid sensitivity because their spatial resolution was not fine enough to capture the variability of these attributes for lakes and ponds with small catchment areas. Many of the lakes are sensitive to acidification (summer and autumn ANC < 100 µeq L−1), but none of them appeared to be threatened immediately by episodic or chronic acidification. In contrast, 22 ponds had minimum ANC < 30 µeq L−1, indicating that they are extremely sensitive to acidic deposition and could be damaged by episodic acidification, although net acidity (ANC < 0) was not measured in any of the ponds during the study. The lowest measured pH value was 5·4, and pH generally remained less than 6·0 throughout early summer in the most sensitive ponds, indicating that biological effects of acidification are possible at levels of atmospheric deposition that occurred during the study. The aquatic chemistry of lakes was dominated by atmospheric deposition and biogeochemical processes in soils and shallow ground water, whereas the aquatic chemistry of ponds was also affected by organic acids and biogeochemical processes in the water column and at the sediment–water interface. These results indicate that conceptual and mechanistic acidification models that have been developed for lakes and streams may be inadequate for predicting acidification in less‐understood systems such as ponds. Copyright © 2004 John Wiley & Sons, Ltd.
Near‐saturated surface soil hydraulic properties under different land uses in the St Denis National Wildlife Area, Saskatchewan, Canada
Authors: Bodhinayake Waduwawatte , Cheng Si Bing
Published: June 2004

Surface soil hydraulic properties are key factors controlling the partition of rainfall and snowmelt into runoff and soil water storage, and their knowledge is needed for sound land management. The objective of this study was to evaluate the effects of three land uses (native grass, brome grass and cultivated) on surface soil hydraulic properties under near‐saturated conditions at the St Denis National Wildlife Area, Saskatchewan, Canada. For each land use, water infiltration rates were measured using double‐ring and tension infiltrometers at −0·3, −0·7, −1·5 and −2·2 kPa pressure heads. Macroporosity and unsaturated hydraulic properties of the surface soil were estimated. Mean field‐saturated hydraulic conductivity (Kfs), unsaturated hydraulic conductivity at −0·3 kPa pressure head, inverse capillary length scale (α) and water‐conducting macroporosity were compared for different land uses. These parameters of the native grass and brome grass sites were significantly (p < 0·1) higher than that of the cultivated sites. At the −0·3 kPa pressure head, hydraulic conductivity of grasslands was two to three times greater than that of cultivated lands. Values of α were about two times and values of Kfs about four times greater in grasslands than in cultivated fields. Water‐conducting macroporosity of grasslands and cultivated fields were 0·04% and 0·01% of the total soil volume, respectively. Over 90% of the total water flux at −0·06 kPa pressure head was transmitted through pores > 1·36 × 10−4 m in diameter in the three land uses. Land use modified near‐saturated hydraulic properties of surface soil and consequently may alter the water balance of the area by changing the amount of surface runoff and soil water storage. Copyright © 2004 John Wiley & Sons, Ltd.
NS398 reduces hypoxia‐inducible factor (HIF)‐1α and HIF‐1 activity: Multiple‐level effects involving cyclooxygenase‐2 dependent and independent mechanisms
Authors: Zhong Hua , Willard Margaret , Simons Jonathan
Published: June 2004

Tissue hypoxia is a common feature in solid tumors. Hypoxia‐inducible factor 1 (HIF‐1) is a critical transcription factor that regulates the expression of genes encoding factors that influence tumor growth including vascular endothelial growth factor. Previous studies have demonstrated that post‐transcriptional modification events are important for regulation of HIF‐1α protein expression and HIF‐1 transcriptional activity. Prostaglandin E2 (PGE2), a major end product of the cyclooxygenase‐2 (COX‐2) enzyme, induces the basal and hypoxia‐induced nuclear relocalization of HIF‐1α. This is suppressed by NS398, a COX‐2 selective inhibitor. NS398 also inhibits hypoxia‐induced angiogenesis, which may be mediated by the inhibition of HIF‐1 function in a COX‐2‐dependent manner. Here, we show that NS398 reduces HIF‐1α and HIF‐1 transcriptional function in both COX‐2 positive PC‐3 cells and COX‐2 negative HCT116 cells under normoxic and hypoxic conditions. On the one hand, NS398 decreases the expression of HIF‐1α mRNA and reduces HIF‐1α synthesis in a COX‐2/PGE2 dependent way, which can be restored by addition of exogenous PGE2 that activates the phosphatidylinositol 3‐kinase/AKT/p70s6k signaling pathway. On the other hand, NS398 accelerates HIF‐1α degradation by moderately increasing ubiquitination and remarkably promoting the clearance of ubiquitylated protein, an effect most likely independent of COX‐2/PGE2 since exogenous PGE2 fails to reverse it. Finally, NS398 decreases hypoxia‐induced shifted form of HIF‐1α and attenuates HIF‐1 activation in greater extent under hypoxic than normoxic conditions. These data not only confirm the inhibitory effect of NS398 on HIF‐1α and HIF‐1 transcriptional activity but also demonstrate that such an effect occurs at multiple levels involving both COX‐2 dependent and independent mechanisms. © 2004 Wiley‐Liss, Inc.
Combination of low‐dose cisplatin and recombinant xenogeneic endoglin as a vaccine induces synergistic antitumor activities
Authors: Tan Guang‐hong , Tian Ling , Wei Yu‐quan , Zhao Xia , Li Jiong , Wu Yang , Wen Yan‐jun , Yi Tao , Ding Zhen‐yu , Kan Bin , Mao Yong‐qiu , Deng Hong‐xin , Li Hong‐li , Zou Chun‐hua , Fu Chun‐hua
Published: June 2004

Angiogenesis is critical to the growth and metastasis of solid tumors, and acquired drug resistance is one of the major hindrances to chemotherapy. Thus, we sought a rational strategy using the combination of antiangiogenic biotherapy and chemotherapy for cancer therapy. We explored the efficacy of a strategy combining low‐dose cisplatin and a recombinant xenogeneic endoglin as a protein vaccine, which we previously demonstrated to have effective antiangiogenic effects in several mouse models. We found that both low‐dosage cisplatin and xenogeneic endoglin vaccine individually resulted in effective suppression of tumor growth in 2 tumor models via inhibition of tumor angiogenesis. Remarkably, the combination therapy resulted in not only significant antiangiogenic effects but also additional promotion of tumor cell apoptosis and inhibition of tumor cell proliferation, without any ensuing increase in host toxicity during the course of treatment, which lasted for 6 months. In addition, the combination demonstrated a synergistic relationship, which was shown in all of the synergistic indexes, i.e., tumor volume, angiogenesis, apoptosis and proliferation. Both antibodies and antibody‐producing B cells against mouse self‐endoglin were observed in all mice immunized by the xenogeneic endoglin vaccine (alone and combination), which suggested that low‐dose cisplatin did not suppress the host immune response but potentiated the antitumor activity of the xenogeneic endoglin vaccine. These observations may provide the basis for an effective alternative strategy for cancer therapy in the near future. © 2004 Wiley‐Liss, Inc.
Temporal evaluation of methionine synthase and related metabolites in the MAC15A mouse adenocarcinoma animal model
Authors: Blackburn Alison , Bibby Michael C. , Lucock Mark D. , Nicolaou Anna
Published: June 2004

Methionine dependence is unique to cancer cells and defined as the inability to grow in a methionine‐deprived environment even if supplemented with the metabolic precursor homocysteine. Cobalamin‐dependent methionine synthase (MS) catalyses the formation of methionine and tetrahydrofolate from homocysteine and methyltetrahydrofolate, thus linking the methionine and folate pathways. The apparent altered methionine metabolism in methionine‐dependent cancer cells suggests a role for MS, although results to date are conflicting. We have analysed key metabolites of the MS‐associated transmethylation, transsulphuration and folate pathways of the methionine‐dependent MAC15A tumour model as a function of tumour progression over a 10‐day period. MS activity increased 2‐fold from day 1 to day 10. Cysteine, homocysteine, S‐adenosylmethionine and S‐adenosylhomocysteine levels in tumour cytosolic fractions decreased as a function of tumour progression. Plasma cysteine levels also decreased, whilst the distribution of folates in erythrocytes was altered, with a maximum increase in methyltetrahydrofolate observed by day 5. The increasing MS activity and decreasing cysteine levels suggest an increasing methionine requirement by the tumour, whilst the induction of enzyme activity indicates that MS is not defective in the methionine‐dependent MAC15A tumour. The decrease in tumour S‐adenosylmethionine and S‐adenosylhomocysteine levels suggests that methionine is required for some function other than cellular methylation, e.g., incorporation into protein. Overall, the results support a theory of methionine conservation in response to tumour growth, where the methionine‐dependent MAC15A tumour has a higher than normal methionine requirement. © 2004 Wiley‐Liss, Inc.
Binding and interstitial penetration of liposomes within avascular tumor spheroids
Authors: Kostarelos Kostas , Emfietzoglou Dimitris , Papakostas Alexandros , Yang Wei‐Hong , Ballangrud Åse , Sgouros George
Published: June 2004

The liposomal delivery of cancer therapeutics, including gene therapy vectors, is an area of intense study. Poor penetration of liposomes into interstitial tumor spaces remains a problem, however. In this work, the penetration of different liposomal formulations into prostate carcinoma spheroids was examined. Spheroid penetration was assessed by confocal microscopy of fluorescently labeled liposomes. The impact of liposomal surface charge, mean diameter, lipid bilayer fluidity and fusogenicity on spheroid penetration was examined. A variety of different liposome systems relevant to clinical or preclinical protocols have been studied, including classical zwitterionic (DMPC:chol) and sterically stabilized liposomes (DMPC:chol:DOPE‐PEG2000), both used clinically, and cationic liposomes (DMPC:DOPE:DC‐chol and DOTAP), forming the basis of the vast majority of nonviral gene transfer vectors tested in various cancer trials. Surface interactions between strongly cationic vesicles and the tumor cells led to an electrostatically derived binding‐site barrier effect, inhibiting further association of the delivery systems with the tumor spheroids (DMPC:DC‐chol). However, inclusion of the fusogenic lipid DOPE and use of a cationic lipid of lower surface charge density (DOTAP instead of DC‐chol) led to improvements in the observed intratumoral distribution characteristics. Sterically stabilized liposomes did not interact with the tumor spheroids, whereas small unilamellar classical liposomes exhibit extensive distribution deeper into the tumor volume. Engineering liposomal delivery systems with a relatively low charge molar ratio and enhanced fusogenicity, or electrostatically neutral liposomes with fluid bilayers, offered enhanced intratumoral penetration. This study shows that a delicate balance exists between the strong affinity of delivery systems for the tumor cells and the efficient penetration and distribution within the tumor mass, similar to previous work studying targeted delivery by ligand‐receptor interactions of monoclonal antibodies. Structure‐function relationships from the interaction of different liposome systems with 3‐dimensional tumor spheroids can lead to construction of delivery systems able to target efficiently and penetrate deeper within the tumor interstitium and act as a screening tool for a variety of therapeutics against cancer. © 2004 Wiley‐Liss, Inc.
Student Ratings: Validity, Utility, and Controversy
Authors: Kulik James A.
Published: June 2004

This chapter reviews the conclusions on which most experts agree, cites some of the main sources of support for these conclusions, and discusses some dissenting opinions and the research support for those opinions.
Assessing the Academic Networked Environment
Authors: Lippincott Joan K.
Published: June 2004

The complexities of a campus information and computing network require a variety of approaches and foci for an effective evaluation.
The Impact of Distance Education on Institutional Research
Authors: Bers Trudy
Published: June 2004

The author discusses how technology's impact on learning and pedagogy—distance learning—presents new challenges to the institutional researcher. The researcher faces a range of challenges, from basic matters of data definition to more complex issues of strategic planning.
Knowledge, Skills, and Effectiveness in Institutional Research
Authors: Knight William E. , Moore Michael E. , Coperthwaite Corby A.
Published: June 2004

Based on a nationwide survey of 601 Association for Institutional Research (AIR) members, this chapter examines the existence and acquisition of institutional research knowledge and skills and how they relate to perceptions of effectiveness.
Emerging Perspectives on Organizational Behavior: Implications for Institutional Researchers
Authors: Schmidtlein Frank A.
Published: June 2004

Assumptions about organizational behavior can lead institutional researchers to misunderstand campus leaders' and policymakers' decisions and actions and thus lessen the impact of their research and recommendations.
Teaching Institutional Research to the Learning‐Inhibited Institution
Authors: Bagshaw Mark
Published: June 2004

Drawing on learning theory, this chapter describes some common organizational learning disabilities that afflict institutions of higher education and proposes some practical solutions.
Aren't You Satisfied Yet? Women Faculty Members' Interpretations of Their Academic Work
Authors: Ropers‐Huilman Becky
Published: June 2004

Arguing that the professional lives of women faculty are different from those of their male counterparts, the author reviews several autobiographical texts focused on female faculty satisfaction.
Faculty Satisfaction in Academic Medicine
Authors: Nyquist Julie G. , Hitchcock Maurice A. , Teherani Arianne
Published: June 2004

Beginning with the current theoretical and conceptual literature related to faculty satisfaction within academic medicine, this chapter hypothesizes a model and offers suggestions for future study.
Job Satisfaction Among Faculty of Color in Academe: Individual Survivors or Institutional Transformers?
Authors: Laden Berta Vigil , Hagedorn Linda Serra
Published: June 2004

This chapter examines the literature on minority faculty and the issues with which they contend from entry through tenure and promotion and into the post‐tenure years.
The Economics of Higher Education: Focus on Cost
Authors: Brinkman Paul T.
Published: June 2004

This chapter provides a concise introduction to the economics of higher education and the multiple factors that converge to determine the cost of higher education.
Building a Consistent and Reliable Expenditure Database
Authors: Armstrong Kelli J.
Published: June 2004

Campus cost studies are effective only when key constituencies have been involved in building the data elements that drive those studies. This chapter is a practical guide to that building process.
To Lift the Veil: New College Cost Studies and the Quest for the Perfect Formula
Authors: Reindl Travis J.
Published: June 2004

The issue of higher education costs has taken on national prominence in recent years. This chapter examines the constructs that are being employed at the national level to study the nature and scope of higher education expenditures.
Understanding the College‐Choice Process
Authors: Cabrera Alberto F. , La Nasa Steven M.
Published: June 2004

This chapter summarizes what we have learned regarding the process that students and their families undergo when making decisions about college. It also presents a comprehensive model synthesizing this literature.
Overcoming the Tasks on the Path to College for America's Disadvantaged
Authors: Cabrera Alberto F. , La Nasa Steven M.
Published: June 2004

Using data from the National Educational Longitudinal Study of 1988, this chapter seeks to gain a better understanding of what factors assist economically and sociologically underprivileged Americans to ready themselves for college.
Transition to College: What Helps At‐Risk Students and Students Whose Parents Did Not Attend College
Authors: Choy Susan P. , Horn Laura J. , Nuñez Anne‐Marie , Chen Xianglei
Published: June 2004

This chapter investigates factors that facilitate postsecondary enrollment for subpopulations of high school students. Students that find themselves at risk and those with parents who have no college experience receive primary consideration.
Racial and Ethnic Group Differences in College Enrollment Decisions
Authors: Perna Laura W.
Published: June 2004

This chapter reviews and synthesizes what is known from prior research about racial and ethnic group differences in college enrollment and identifies areas for intervention. This chapter is relevant to campus administrators, institutional researchers, and others who are interested in raising the share of African Americans and Hispanics who are enrolling in U.S. colleges and universities.
Preparing America's Disadvantaged for College: Programs That Increase College Opportunity
Authors: Swail Watson Scott
Published: June 2004

This chapter reviews many of the major programs seeking to increase college access among economically disadvantaged and at‐risk students. The author evaluates the potential of these programs while stressing four conditions that effective programs must meet.
Overview of Student Affairs Research Methods: Qualitative and Quantitative
Authors: Perl Emily J. , Noldon Denise F.
Published: June 2004

This chapter provides a review of the strengths and weaknesses of quantitative and qualitative research and argues for the value of using the paradigms complementarily.
Competencies, Regional Accreditation, and Distance Education: An Evolving Role?
Authors: Terkla Dawn Geronimo
Published: June 2004

This chapter provides an overview of the link between competencies and current accreditation standards and examines the influence of distance education on the accreditation landscape. Techniques are suggested that institutional researchers can use to position their institutions advantageously in the contemporary accreditation process.
Creating and Implementing Competency‐Based Learning Models
Authors: Voorhees Alice Bedard
Published: June 2004

Institutional researchers can take the lead in addressing the public and workplace call for greater institutional accountability by educating their colleagues about the possibilities inherent in competency‐based learning models and by assisting with the evaluative efforts to implement these models.
How Do Student Ratings Measure Up to a New Validity Framework?
Authors: Ory John C. , Ryan Katherine
Published: June 2004

The authors examine student ratings within a new framework that emphasizes six distinct aspects of validity: content, substantive, structural, generalizability, external, and consequential. They conclude that greater attention should be directed toward consequential validity, particularly the matters of how ratings are used on today's campuses and what happens as a result.
Conceptual Models for Creating Useful Decision Support
Authors: Howard Richard D.
Published: June 2004

Using Senge's rationale for the creation of mental models, this chapter presents a series of conceptual models that provide guidance for the creation of effective decision support.
The Use of Quantitative and Qualitative Information in Institutional Decision Making
Authors: Perkins Mark L.
Published: June 2004

At the executive level, decisions require a systems approach to the creation of data and information that will provide the decision maker with certainty about the right decision.
Qualitative and Quantitative Measures: One Driver of a Quality Culture
Authors: Fife Jonathan D.
Published: June 2004

One of the three drivers in the development and maintenance of a quality institution is the ability not only to measure institutional input and output but also to interpret these measures in light of understanding stakeholder expectations and needs.
Ub on the move
Authors: Shcherbik Natalia , Haines Dale S.
Published: June 2004

Ubiquitination is an increasingly common post‐translation modification that controls both the expression and activity of numerous proteins in the eukaryotic cell. One frequent target of the ubiquitin (Ub) modification machinery is transcription factors. Although ubiquitination generally modulates their function by inducing proteasome‐dependent degradation, past and recent studies indicate that ubiquitination also regulates nuclear–cytoplasmic trafficking of transcriptional regulators. Ubiquitination is known to modulate transcription factor localization by destroying sequestering proteins and by directly promoting nuclear import and export of modified substrates. This review discusses old and new paradigms relating Ub modification and the control of transcription factor shuttling in and out of the nucleus. © 2004 Wiley‐Liss, Inc.
Non‐thermal effects of electromagnetic fields at mobile phone frequency on the refolding of an intracellular protein: Myoglobin
Authors: Mancinelli Fabrizio , Caraglia Michele , Abbruzzese Alberto , d'Ambrosio Guglielmo , Massa Rita , Bismuto Ettore
Published: June 2004

Non‐thermal effects induced by exposure to microwave electromagnetic field (MW‐EMF) at 1.95 MHz, a frequency used in mobile communication, have been observed on the refolding kinetics of the heme binding site in an intracellular protein: tuna myoglobin, starting from acidic conditions. We have selected myoglobin because it can be considered a good model to study protein interactions with MW‐EMF for its well‐known high‐resolution crystallographic structure. Myoglobin solutions at pH 3.0 were subjected to 3 h exposure to microwave field (with a specific absorption rate of 51 ± 1 mW/g); the heme site refolding has been followed by measuring the molecular absorption in the Soret spectral region and the data were fitted to a bi‐exponential model. The kinetics of exposed samples appear to be slowered by MW‐EMF action. Moreover, the tryptophanyl lifetime distribution of the exposed protein, as deduced by the analysis of the fluorescence emission decay from its single tryptophan, appears sharper if compared to non‐exposed protein samples. This observation suggests that the presence of MW‐EMF could affect the propensity of protein molecules to populate specific conformational substates among which myoglobin molecules fluctuate at acidic pH. Changes in the structural fluctuation caused by MW perturbation can affect differently the aggregation process that occurs competitively during the protein folding, so representing a potential risk for protein “misfolding.” These data suggest that MW‐EMF could have also biochemical and, consequently, biological effects on eukaryotic cells that are still under investigation. © 2004 Wiley‐Liss, Inc.
Role of serotonin, γ‐aminobutyric acid, and glutamate in the behavioral thermoregulation of female tilapia during the prespawning phase
Authors: Tsai Ching‐Lin , Wang Li‐Hsueh , Tsai Chia‐Chiun
Published: June 2004

The role of hypothalamic neurotransmitter systems in behavioral thermoregulation was investigated in the prespawning female tilapia, Oreochromis mossambicus. Intrahypothalamic microinjection with serotonin (5‐HT, 3 µl of 1.0×10−6 M) resulted in a significant increase in the selected temperature. This effect was mimicked by the agonist of 5‐HT1A, 1B, and 2C receptors, N‐3‐trifluoromethylphenyl piperazine. Intrahypothalamic microinjection of tilapia with γ‐aminobutyric acid (GABA) resulted in a biphasic effect of the temperature selection, whereas microinjection with muscimol, an agonist of GABAA receptor, had no effect on temperature selection. Both agonist and antagonist of glutamate (Glu), N‐methyl‐D‐aspartate (NMDA), and MK‐801 (1.0×10−6 M), a noncompetitive blocker of NMDA receptor, significantly decreased the preferred temperature. These results indicate that the hypothalamic 5‐HT, GABA, and Glu systems play a role in the temperature selection of prespawning female tilapia. J. Exp. Zool. 293:443–449, 2002. © 2002 Wiley‐Liss, Inc.
Skin flaps inhibit both the current of injury at the amputation surface and regeneration of that limb in newts
Authors: Altizer Alicia M. , Stewart Sarah G. , Albertson Brian K. , Borgens Richard B.
Published: June 2004

For over two decades, we have been investigating a strong (ca. 20–100 µA/cm2), outwardly directed electric current driven through the limb stump for the first few days following amputation in regenerating salamanders. This current is driven through the stump in a proximal/distal direction by the amiloride‐sensitive transcutaneous voltage of the intact skin of the stump. Limb regeneration can be manipulated by several techniques that manipulate this physiology, demonstrating that the ionic current is necessary, but not sufficient, for normal regeneration of the amphibian limb. Here, we demonstrate that a full thickness graft of skin covering the forelimb stump of newts strikingly inhibits the regeneration of the limb, and that this procedure is also highly correlated to a suppression of peak outwardly directed stump currents in those animals that fail to regenerate. J. Exp. Zool. 293:467–477, 2002. © 2002 Wiley‐Liss, Inc.
Effects of posture on the respiratory mechanics of the chick embryo
Authors: Menna Tara M. , Mortola Jacopo P.
Published: June 2004

In the chicken embryo, pulmonary ventilation and pulmonary gas exchange begin approximately one day before the completion of hatching. We asked to what extent the posture inside the egg, and the presence of the eggshell and membranes, may alter the mechanical behaviour of the respiratory system. The passive mechanical properties of the respiratory system were studied in chicken embryos during the internal pipping phase (rupture of the air cell) or the external pipping phase (hole in the eggshell). Tracheal pressure and changes in lung volume were recorded during mechanical ventilation, first, with the embryo curled up inside the egg, then again after exteriorization from the eggshell. In the internal pippers, respiratory system compliance increased and expiratory resistance decreased after exteriorization, whereas the mean inspiratory impedance did not change. In the external pippers, exteriorization had no significant effects on respiratory compliance, resistance, or impedance, and the values were similar to those of newly hatched chicks. We conclude that, in the chicken embryo, at a time when pulmonary ventilation becomes an important mechanism for gas exchange, the curled up posture inside the egg does not provide any significant mechanical constraint to breathing. J. Exp. Zool. 293:450–455, 2002. © 2002 Wiley‐Liss, Inc.
Mollusc larval shell formation: amorphous calcium carbonate is a precursor phase for aragonite
Authors: Weiss Ingrid Maria , Tuross Noreen , Addadi Lia , Weiner Steve
Published: June 2004

The larval shells of the marine bivalves Mercenaria mercenaria and Crassostrea gigas are investigated by polarized light microscopy, infrared spectroscopy, Raman imaging spectroscopy, and scanning electron microscopy. Both species contain similar shell ultrastructures. We show that larval shells contain amorphous calcium carbonate (ACC), in addition to aragonite. The aragonite is much less crystalline than nonbiogenic aragonite. We further show that the initially deposited mineral phase is predominantly ACC that subsequently partially transforms into aragonite. The postset juvenile shell, as well as the adult shell of Mercenaria also contains aragonite that is less crystalline than nonbiogenic aragonite. We conclude that ACC fulfills an important function in mollusc larval shell formation. It is conceivable that ACC may also be involved in adult shell formation. J. Exp. Zool. 293:478–491, 2002. © 2002 Wiley‐Liss, Inc.
Characterization of aromatase activity in the sea bass: effects of temperature and different catalytic properties of brain and ovarian homogenates and microsomes
Authors: González Alicia , Piferrer Francesc
Published: June 2004

Two aromatase genes have been discovered in the brain and ovary of some teleosts. However, data on native aromatase enzyme kinetics and thus actual catalytic activity are scarce in fish, impeding comparison of aromatase activity (AA) from different organs within and between species. In the present study, the tritiated water assay was optimized and validated to measure AA in the sea bass using 1β‐[3H]‐androstenedione as a substrate in crude homogenates and microsomes. Optimized assay variables included pH, temperature, buffer strength, incubation time, amount of fresh tissue, substrate, and cofactor concentration. Specificity of the assay was verified by using known inhibitors, inappropriate substrates, and heat‐inactivation. Subcellular fractionation revealed ten‐fold more activity in the microsomal over the cytosolic fraction. The assay was also validated by comparing results from the direct product isolation method. The validated assay described allows measurement of AA to levels as low as < 10 fmol/mg protein/hr. Sex differentiation is temperature‐dependent in the sea bass. It was found that in the physiological range of temperatures where the sea bass can live, 10–30°C, AA is highly dependent on temperature in a linear fashion (brain: r2 = 0.92; P<0.001; ovary: r2 = 0.94; P<0.001). When AA levels from brain and ovarian homogenates obtained from the same fish during the spawning season were compared, the respective Michaelis‐Menten constant (Km) values were 7.3 nM vs. 4.6 nM, with no significant differences detected between the two tissues. Thus, sea bass aromatase has a very high affinity for androstenedione, similar to what has been found in goldfish, but much higher than other piscine or mammalian aromatases (30–435 nM). In contrast, the brain maximum reaction rate (Vmax 7.8 pmol/mg protein/hr) was four‐fold higher (P<0.001) than the ovarian Vmax (2.1 pmol/mg protein/hr). Consistent results were found using purified microsomes. Although this is the first time that the kinetic parameters are reported for a native piscine aromatase in two different tissues within the same fish, it remains to be determined whether this is a reflection of two distinct isoforms in this particular species. J. Exp. Zool. 293:500–510, 2002. © 2002 Wiley‐Liss, Inc.
Induction of parturition in snow skinks: can low temperatures inhibit the actions of AVT?
Authors: Girling Jane E. , Jones Susan M. , Swain Roy
Published: June 2004

The influence of environmental factors on the timing of parturition has not been investigated in viviparous squamates. We investigated the interaction between temperature and parturition in two viviparous skink species, the southern snow skink (Niveoscincus microlepidotus) and the metallic skink (N. metallicus). In these species, the timing of parturition is separated from the completion of embryonic development; the delay is attributed to their cool and variable habitats. We examined whether the neurohypophyseal hormone arginine vasotocin (AVT) stimulated parturition in southern snow skinks with late stage embryos in autumn (≈6–7 months prior to parturition) and in metallic skinks with late stage embryos in summer (≈2–3 weeks prior to parturition). The experiments were conducted at a range of environmentally relevant temperatures (6°C, 15°C, 22°C, and 28°C). AVT induced parturition in both species at all temperatures; time until birth, however, occurred more quickly at warmer temperatures (22°C and 28°C), whereas cooler temperatures delayed parturition. We hypothesize that if cool temperatures are preventing parturition, then temperature must act at some level within the brain to prevent or slow the secretion of AVT. Future experiments will need to determine how temperature influences AVT production. Further research is also required to determine how the timing of parturition is influenced by interactions between temperature, photoperiod, and seasonal hormone patterns. J. Exp. Zool. 293:525–531, 2002. © 2002 Wiley‐Liss, Inc.
A biographical note on Max Friedrich (1856–1887), Wundt's first PhD student in experimental psychology
Authors: Domanski Cezary W.
Published: June 2004

This article unveils some previously unknown facts about the short life of Max Friedrich (1856–1887), the author in 1881 of the first PhD dissertation on experimental psychology, written under the supervision of Wilhelm Wundt: “On the Duration of Apperception for Simple and Complex Visual Stimuli.” The article describes Friedrich's family background and life, professional career as a teacher, and works in psychology and mathematics. © 2004 Wiley Periodicals, Inc.
Historiography taking issue: Analyzing an experiment with heroin abusers
Authors: Dehue Trudy
Published: June 2004

This article discusses the predicament of historians becoming part of the history they are investigating and illustrates the issue in a particular case. The case is that of the randomized controlled trial (RCT)—more specifically, its use for testing the effects of providing heroin to severe heroin abusers. I counter the established view of the RCT as a matter of timeless logic and argue that this research design was developed in the context of administrative knowledge making under twentieth‐century economic liberalism of which it epitomizes some central values. I also argue that the applicability of the RCT depends on the degree to which its advocates can define the issue to be studied according to its inherent values. Next, I demonstrate how advocates of an RCT with heroin provision in the Netherlands steered the political discussion on heroin provision and how the values of economic liberalism also shaped the results of the Dutch maintenance experiment. In addition, I relate how my analysis of this experiment became part of political debates in the Netherlands. Contrary to my intentions, adversaries of heroin maintenance used my critique on the heroin RCT as an argument against heroin maintenance. Such risks are inherent to historiography and sociology of science aiming at practical relevance while challenging treasured scientific beliefs. I conclude that it still seems better to expose arguments on unjustified certainties than to suppress them for strategic reasons. © 2004 Wiley Periodicals, Inc.
The establishment of the department of psychiatry in the Mount Sinai Hospital: A conflict between neurology and psychiatry
Authors: Stein Marvin
Published: June 2004

A conflict between neurology and psychiatry and controversies about psychoanalysis played an important role in the establishment of psychiatry in the general hospital. This article reviews the impact of this conflict on the establishment of an independent Department of Psychiatry in the Mount Sinai Hospital in New York during the first half of the twentieth century. A unique opportunity is provided to consider the relationships and personalities of the individuals involved, as well as economic, social, and scientific factors, including the introduction of psychoanalysis as a major psychiatric treatment. © 2004 Wiley Periodicals, Inc.
Mass spectrometry and partial least‐squares regression: a tool for identification of wheat variety and end‐use quality
Authors: Sørensen Helle A. , Petersen Marianne K. , Jacobsen Susanne , Søndergaard Ib
Published: June 2004

Rapid methods for the identification of wheat varieties and their end‐use quality have been developed. The methods combine the analysis of wheat protein extracts by mass spectrometry with partial least‐squares regression in order to predict the variety or end‐use quality of unknown wheat samples. The whole process takes ∼30 min. Extracts of alcohol‐soluble storage proteins (gliadins) from wheat were analysed by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Partial least‐squares regression was subsequently applied using these mass spectra for making models that could predict the wheat variety or end‐use quality. Previously, an artificial neural network was used to identify wheat varieties based on their protein mass spectra profiles. The present study showed that partial least‐squares regression is at least as useful as neural networks for this identification. Furthermore, it was demonstrated that partial least‐squares regression could be used to predict wheat end‐use quality, which has not been possible using neural networks. Copyright © 2004 John Wiley & Sons, Ltd.
Internal energy build‐up in matrix‐assisted laser desorption/ionization
Authors: Gabelica Valérie , Schulz Eric , Karas Michael
Published: June 2004

This paper reports detailed studies on the internal energy of ions formed in matrix‐assisted laser desorption/ionization (MALDI) using delayed extraction MALDI‐time‐of‐flight (TOF) and atmospheric pressure (AP) MALDI mass spectrometric (MS) methods. We use benzylpyridinium cations as internal energy probes. Our study reveals three distinct contributions to internal energy build‐up in vacuum‐MALDI (classical MALDI‐TOF), each having different effects on ion fragmentation. Some fragments are formed before ion extraction (i.e. no more than 100 ns after the laser impact), and they are therefore well resolved and recorded as sharp signals in the MALDI‐TOFMS scan. This prompt fragmentation can have two origins: (i) in‐plume thermal activation, presumably always present, and (ii) in‐plume chemical activation, in the course of reactions with hydrogen radicals. In addition to early internal energy build‐up associated with these well‐resolved promptly formed fragments, a broad peak slightly offset to higher masses could be detected corresponding to fragments formed after the extraction has started. This second signal corresponds to a third source of internal energy in MALDI ions, (iii) the extraction‐induced collisional activation of the ions with the neutral components of the plume. These three contributions are difficult to quantify in vacuum‐MALDI, because of the combined influence of several parameters (nature of the matrix, spot‐to‐spot variability, total laser exposure, delay time, acceleration voltage) on extraction‐induced fragmentation. AP‐MALDI, on the other hand, has two advantages for comparative studies of analyte fragmentation. First, extraction‐induced fragmentation is absent, and only the contributions of early plume activation remain. Second, the reproducibility is far better than in vacuum‐MALDI. AP‐MALDI is therefore expected to shed new light on the early steps of the MALDI process. Copyright © 2004 John Wiley & Sons, Ltd.
Intact‐protein based sample preparation strategies for proteome analysis in combination with mass spectrometry
Authors: Wang Hong , Hanash Sam
Published: June 2004

The complexity of tissue and cell proteomes and the vast dynamic range of protein abundance present a formidable challenge for analysis that no one analytical technique can overcome. As a result, there is a need to integrate technologies to achieve the high‐resolution and high‐sensitivity analysis of complex biological samples. The combined technologies of separation science and biological mass spectrometry (Bio‐MS) are the current workhorse in proteomics, and are continuing to evolve to meet the needs for high sensitivity and high throughput. They are relied upon for protein quantification, identification, and analysis of post‐translational modifications (PTMs). The standard technique of two dimensional poly‐acrylamide gel electrophoresis (2D PAGE) offers relatively limited resolution and sensitivity for the simultaneous analysis of all cellular proteins, with only the most highly abundant proteins detectable in whole cell or tissue‐derived samples. Hence, many alternative strategies are being explored. Numerous sample preparation procedures are currently available to reduce sample complexity and to increase the detectability of low‐abundance proteins. Maintaining proteins intact during sample preparation has important advantages compared with strategies that digest proteins at an early step. These strategies include the ability to quantitate and recover proteins, and the assessment of PTMs. A review of current intact protein‐based strategies for protein sample preparation prior to mass spectrometry (MS) is presented in the context of biomedically driven applications. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:413–426, 2005
Proteome analysis in the study of lymphoma cells
Authors: Joubert‐Caron Raymonde , Caron Michel
Published: June 2004

This review provides an overview on recent studies in the field of proteome analysis of lymphoma cells, and highlights the potentials of such studies for a better knowledge of drug effects at the molecular level. After giving general information on the field of proteome analysis of lymphoma cells, some characteristics of the strategies used during this analysis are pointed out, such as cell extraction strategies and affinity captures. Therefore, the issue of proteome analysis of lymphoma cells content will be covered with respect to those protein extracts that can be prepared in saline solutions, such as cytoplasm proteins, or that are associated with the cell membranes. The question of which kinds of information have been retrieved from lymphoma‐cell proteomics is discussed on the basis of several examples—lymphoma cell‐mapping studies and constitution of protein databases, and comparative proteome analysis studies of the modifications that result from a drug treatment. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:455–468, 2005
Mechanical, Chemical and Tribological Properties of the Nickel‐free High‐Nitrogen Steel X13CrMnMoN18‐14‐3 (1.4452)
Authors: Koch S. , Büscher R. , Tikhovski I. , Brauer H. , Runiewicz A. , Dudzinski W. , Fischer A.
Published: June 2004

Due to the fact that the risk of Ni‐allergies are more and more important for modern therapies, the need of Ni‐free implant materials becomes increasingly vital. Beside Co‐ and Ti‐base alloys the new Ni‐free high‐Nitrogen steels might offer an attractive alternative to these expensive materials. The high‐Nitrogen and Ni‐free stainless steel X13CrMnMoN18‐4‐3 (1.4452) is investigated in the solution annealed state as to its corrosion, fatigue and sliding wear behaviour in Ringer solution. Under all test stresses this steel revealed a better behaviour as the conventional 316L‐type X2CrNiMo18‐15‐3. When compared to literature data of solution annealed Ni‐containing high‐Nitrogen steels and Ni‐free Co‐base alloys the 1.4452 shows similar bahaviour. The good fatigue behaviour is attributed to the low stacking fault energy resulting in the total absence of climbing and cross slip. The corrosion properties can be related to the amount of dissolved N. The sliding wear behaviour in a self‐mating contact benefits from both the low stacking fault energy and the characteristic corrosion mechanisms. Together with the elsewhere reported non‐cytotoxicity the steel X13CrMnMoN18‐4‐3 (1.4452) can be considered being suitable for medical applications.