bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatic tissue engineering: from transplantation to customized cell‐based liver directed therapies from the laboratory
Authors: Fiegel Henning C. , Kaufmann Peter M. , Bruns Helge , Kluth Dietrich , Horch Raymund E. , Vacanti Joseph P. , Kneser Ulrich
Published: March 2008

Introduction

Development of cell isolation and primary culture for hepatocytes

Three–dimensional culture using matrices

Development of bioreactor systems for liver cells

First clinical application of bioreactors with liver cells

Development of matrix‐based hepatocyte transplantation

Outlook: future perspective for the development of successful tissue engineering approaches for transplantation

Today, liver transplantation is still the only curative treatment for liver failure due to end‐stage liver diseases. Donor organ shortage, high cost and the need of immunosuppressive medications are still the major limitations in the field of liver transplantation. Thus, alternative innovative cell‐based liver directed therapies, for example, liver tissue engineering, are under investigation with the aim that in future an artificial liver tissue could be created and be used for the replacement of the liver function in patients. Using cells instead of organs in this setting should permit (i) expansion of cells in an in vitro phase, (ii) genetic or immunological manipulation of cells for transplantation, (iii) tissue typing and cryopreservation in a cell bank and (iv) theex vivogenetic modification of patient's own cells prior to re‐implantation. Function and differentiation of liver cells are influenced by the three‐dimensional organ architecture. The use of polymeric matrices permits the three‐dimensional formation of a neo tissue and specific stimulation by adequate modification of the matrix surface, which might be essential for appropriate differentiation of transplanted cells. In addition, culturing hepatocytes on three‐dimensional matrices permits culture in a flow bioreactor system with increased function and survival of the cultured cells. Based on bioreactor technology, bioartificial liver devices (BAL) are developed for extracorporeal liver support. Although BALs improved clinical and metabolic conditions, increased patient survival rates have not been proven yet. For intracorporeal liver replacement, a concept that combines tissue engineering using three‐dimensional, highly porous matrices with cell transplantation could be useful. In such a concept, whole liver mass transplantation, long‐term engraftment and function as well as correction of a metabolic defect in animal models could be achieved with a principally reversible procedure. Future studies have to investigate which environmental conditions and transplantation system would be most suitable for the development of artificial functional liver tissue including blood supply for a potential use in a clinical setting.
Cancer stem cells: the lessons from pre‐cancerous stem cells
Authors: Gao Jian‐Xin
Published: March 2008

Introduction

Stem cells and cancer stem cells

Development of pre‐cancerous and cancer stem cells

Characteristics of pre‐cancerous versuscancer stem cells

Are there demarcations between pre‐cancerous and cancer stem cells

Contribution of pre‐cancerous and cancer stem cells to tumour malignancy

Clonal evolution underlies the development of tumour‐initiating cell (TIC) → pre‐cancerous stem cell (pCSC) → cancer stem cell (CSC)

Molecular pathways for the development of pre‐cancerous and cancer stem cells

Experimental models for pre‐cancerous and cancer stem cell research

Clinical implications: early detection, prevention and treatment via targeting of pre‐cancerous and cancer stem cells

Concluding remark

How a cancer is initiated and established remains elusive despite all the advances in decades of cancer research. Recently the cancer stem cell (CSC) hypothesis has been revived, challenging the long‐standing model of ‘clonal evolution’ for cancer development and implicating the dawning of a potential cure for cancer [1]. The recent identification of pre‐cancerous stem cells (pCSCs) in cancer, an early stage of CSC development, however, implicates that the clonal evolution is not contradictory to the CSC hypothesis but is rather an aspect of the process of CSC development [2]. The discovery of pCSC has revealed and will continue to reveal the volatile properties of CSC with respect to their phenotype, differentiation and tumourigenic capacity during initiation and progression. Both pCSC and CSC might also serve as precursors of tumour stromal components such as tumour vasculogenic stem/progenitor cells (TVPCs). Thus, the CSC hypothesis covers the developing process of tumour‐initiating cells (TIC) → pCSC → CSC → cancer, a cellular process that should parallel the histological process of hyperplasia/metaplasia (TIC) → pre‐cancerous lesions (pCSC) → malignant lesions (CSC → cancer). The embryonic stem (ES) cell and germ line stem (GS) cell genes are subverted in pCSCs. Especially the GS cell protein piwil2 may play an important role during the development of TIC → pCSC → CSC, and this protein may be used as a common biomarker for early detection, prevention, and treatment of cancer. As cancer stem cell research is yet in its infancy, definitive conclusions regarding the role of pCSC cannot be made at this time. However, this review will discuss what we have learned from pCSC and how this has led to innovative ideas that may eventually have major impacts on the understanding and treatment of cancer.
Differential expression of microRNAs in myometrium and leiomyomas and regulation by ovarian steroids
Authors: Pan Qun , Luo Xiaoping , Chegini Nasser
Published: March 2008

Given the emerging roles of microRNAs (miRNAs) as key regulator of mRNA stability we assessed their expression profile in paired myometrium and leiomyoma, their isolated smooth muscle cells (MSMC and LSMC), a spontaneously transformed leiomyoma smooth muscle cells (T‐LSMC) and SK‐LMS‐1, a leiomyosarcoma cell line using microarray and real time PCR.Based on global normalization of expression values of 385 miRNAs and statistical analysis (anova), 91 miRNAs were expressed above the threshold levels in myometrium, with a progressive decline in numbers in leiomyomas, MSMC, LSMC, T‐LSMC and SK‐LMS‐1 (P<0.05).We selected and validated the expression of miR‐20a, miR‐21, miR‐26a, miR‐18a, miR‐206, miR‐181a and miR‐142–5p and found their differential expression in tissue and cell‐specific manners (P<0.05).Treatments of MSMC and LSMC with 17β estradiol and medroxyprogesterone acetate (10−8M), or ICI‐182780 and RU‐486 (10−6M) resulted in differential regulation of these miRNAs (P<0.05).In conclusion, the expression of a number of miRNAs in myometrium and leiomyoma with their progressive aberrant from normal MSMC into LSMC, transformed and cancerous stage, suggests that miRNAs and their regulation by ovarian steroids play a key role in pathogenesis of leiomyoma through gene expression stability.
Atrial extracellular matrix remodelling in patients with atrial fibrillation
Authors: Polyakova V. , Miyagawa S. , Szalay Z. , Risteli J. , Kostin S.
Published: March 2008

Atrial fibrillation (AF) is the most frequent clinical arrhythmia. Atrial fibrosis is an important factor in initiating and maintaining AF. However, the collagen turnover and its regulation in AF has not been completely elucidated. We tested the hypothesis that the extracellular matrix changes are more severe in patients with permanent AF in comparison with those in patients in sinus rhythm (SR). Intraoperative biopsies from the right atrial appendages (RAA) and free walls (RFW) from 24 patients with AF undergoing a mini‐Maze procedure and 24 patients in SR were investigated with qualitative and quantitative immunofluorescent and Western blot analyses. As compared with SR, all patients with AF exhibited dysregulations in collagen type I and type III synthesis/degradation. Tissue inhibitors of metalloproteinases (TIMP2) was significantly enhanced only in RAA‐AF. As compared with SR, collagen VI, matrix metalloproteinases MMP2, MMP9 and TIMP1 were significantly increased while TIMP3 and TIMP4 remained unchanged in all AF groups. Reversion‐inducing cysteine‐rich protein with Kazal motifs (RECK), a newly discovered MMPs inhibitor, was elevated in RFW as compared to RAA‐AF (P<0.05) and RFW‐SR (P<0.05). The level of transforming growth factor (TGF)‐β1 was higher in AF than SR. Smad2 and phosphorylated Smad2 showed an elevation in RFW‐AF as compared to RFW‐SR, RAA‐AF, and RAA‐SR groups (P<0.05). Conclusions: Atrial fibrosis in AF is characterized by severe alterations in collagen I and III synthesis/degradation associated with disturbed MMP/TIMP systems and increased levels of RECK. TGF‐β1 contributes to atrial fibrosis via TGF‐β1‐Smad pathway by phospho‐rylating Smad2. These processes culminate in accumulations of fibrillar and non‐fibrillar collagens leading to excessive atrial fibrosis and maintainance of AF.
In vivo detection of c‐Met expression in a rat C6 glioma model
Authors: Towner R.A. , Smith N. , Doblas S. , Tesiram Y. , Garteiser P. , Saunders D. , Cranford R. , Silasi‐Mansat R. , Herlea O. , Ivanciu L. , Wu D. , Lupu F.
Published: March 2008

The tyrosine kinase receptor, c‐Met, and its substrate, the hepatocyte growth factor (HGF), are implicated in the malignant progression of glioblastomas. In vivo detection of c‐Met expression may be helpful in the diagnosis of malignant tumours. The C6 rat glioma model is a widely used intracranial brain tumour model used to study gliomas experimentally. We used a magnetic resonance imaging (MRI) molecular targeting agent to specifically tag the cell surface receptor, c‐Met, with an anti‐c‐Met antibody (Ab) linked to biotinylated Gd (gadolinium)‐DTPA (diethylene triamine penta acetic acid)‐albumin in rat gliomas to detect overexpression of this antigen in vivo. The anti‐c‐Met probe (anti‐c‐Met‐Gd‐DTPA‐albumin) was administered intravenously, and as determined by an increase in MRI signal intensity and a corresponding decrease in regional T1 relaxation values, this probe was found to detect increased expression of c‐Met protein levels in C6 gliomas. In addition, specificity for the binding of the anti‐c‐Met contrast agent was determined by using fluorescence microscopic imaging of the biotinylated portion of the targeting agent within neoplastic and ‘normal’brain tissues following in vivo administration of the anti‐c‐Met probe. Controls with no Ab or with a normal rat IgG attached to the contrast agent component indicated no non‐specific binding to glioma tissue. This is the first successful visualization of in vivo overexpression of c‐Met in gliomas.
Alzheimer neurofibrillary degeneration: significance, etiopathogenesis, therapeutics and prevention
Authors: Iqbal K. , Grundke‐Iqbal I.
Published: March 2008

Introduction

Significance

Etiopathogenesis

Mechanism by which ab normal hyperphosphorylation of tau leads to neurofibrillary degeneration

Signal transduction pathways involved

Role of decreased brain glucose metabolism in neurofibrillary degeneration

Subgroups of AD

Therapeutic approaches to inhibit neurofibrillary degeneration

Alzheimer disease (AD) is multi‐factorial and heterogeneous. Independent of the aetiology, this disease is characterized clinically by chronic and progressive dementia and histopathologically by neurofibrillary degeneration of abnormally hyperphosphorylated tau seen as intraneuronal neurofibrillary tangles, neuropil threads and dystrophic neurites, and by neuritic (senile) plaques of β‐amyloid. The neurofibrillary degeneration is apparently required for the clinical expression of AD, and in related tauopathies it leads to dementia in the absence of amyloid plaques. While normal tau promotes assembly and stabilizes microtubules, the abnormally hyperphosphorylated tau sequesters normal tau, MAP1 and MAP2, and disrupts microtubules. The abnormal hyperphosphorylation of tau also promotes its self‐assembly into tangles of paired helical and or straight filaments. Tau is phosphorylated by a number of protein kinases. Glycogen synthase kinase‐3 (GSK‐3) and cyclin dependent protein kinase 5 (cdk5) are among the kinases most implicated in the abnormal hyperphosphorylation of tau. Among the phosphatases which regulate the phosphorylation of tau, protein phosphatase‐2A (PP‐2A), the activity of which is down‐regulated in AD brain, is by far the major enzyme. The inhibition of abnormal hyperphosphorylation of tau is one of the most promising therapeutic targets for the development of disease modifying drugs. A great advantage of inhibiting neurofibrillary degeneration is that it can be monitored by evaluating the levels of total tau and tau phosphorylated at various known abnormally hyperphosphorylated sites in the cerebrospinal fluid of patients, obtained by lumbar puncture. There are at least five subgroups of AD, each is probably caused by a different etiopathogenic mechanism. The AD subgroup identification of patients can help increase the success of clinical trials and the development of specific and potent disease modifying drugs.
Interstitial Cajal‐like cells in rat mesentery: an ultrastructural and immunohistochemical approach
Authors: Hinescu M. E. , Popescu L. M. , Gherghiceanu M. , Faussone‐Pellegrini M.‐S.
Published: March 2008

Interstitial Cajal‐like Cells (ICLC) were recently recognized in a plethora of non‐digestive organs. Here, we describe a cell type of rat mesentery sharing ultrastructural and immunohistochemical features with ICLC. Mesenteric ICLC were demonstrated by transmission electron microscopy (TEM) and further tested by light microscope immunohistochemistry. The cell described here fulfils the TEM diagnostic criteria accepted for ICLC: location in the connective interstitium; close vicinity to nerves, capillaries and other interstitial cells; characteristic long, moniliform cell processes; specialized cell‐to‐cell junctions; caveolae; mitochondria at 5–10% of cytoplasmic volume; rough endoplasmic reticulum at about 1–2%; intermediate and thin filaments, microtubules; undetectable thick filaments. The processes of this mesenteric ICLC were particularly long, with a mean length of 24.91 μm (10.27–50.83 μm), and a convolution index of 2.32 (1.37–3.63) was calculated in order to measure their potential length. Mean distances versus main target cells of ICLC–nerve bundles, vessels, adipocytes and macrophages–were 110.69, 115.80, 205.07 and 34.65 nm, respectively. We also tested the expression of CD117/c‐kit, CD34, vimentin, α‐smooth muscle actin, nestin, NK‐1, tryptase and chymase and the antigenic profile of the mesenteric ICLC was comparable if not identical with that recently observed in ICLC from other extra‐digestive tissues. Due to the peculiar aspect of the mesenteric ICLC processes it can be hypothesized that these cells form a three‐dimensional network within the mesentery that is at the same time resistant and deformable following stretches consequent to intestine movements, mainly avoiding blood vessels closure or controlling blood vessels rheology. It remains, however, to be established if and how such cells are connected with the archetypal enteric ICC.
Phosphorylated PP2A (tyrosine 307) is associated with Alzheimer neurofibrillary pathology
Authors: Liu R. , Zhou X.‐W. , Tanila H. , Bjorkdahl C. , Wang J.‐Z. , Guan Z.‐Z. , Cao Y. , Gustafsson J.‐Å. , Winblad B. , Pei J.‐J.
Published: March 2008

Down‐regulation of protein phosphatase 2A (PP2A) is thought to play a critical role in tau hyperphosphorylation in Alzheimer's disease (AD). In vitro phosphorylation of PP2A catalytic subunit at Y307 efficiently inactivates PP2A. A specific antibody against phosphorylated (p) PP2A (Y307) (PP2Ac‐Yp307) was used to investigate possible PP2A down‐regulation by known pathophysiological changes associated with AD, such as Aβ accumulation and oestrogen deficiency. Immunohistochemistry and immunofluorescence confocal microscopy showed an aberrant accumulation of PP2Ac‐Yp307 in neurons that bear pretangles or tangles in the susceptible brain regions, such as the entorhinal cortical cortex and the hippocampus. Experimentally, increased PP2Ac‐Yp307 was observed in mouse N2a neuroblastoma cells that stably express the human amyloid precursor protein with Swedish mutation (APPswe) compared with wild‐type, and in the brains of transgenic APPswe/ presenilin (PS1, A246E) mice, which corresponded to the increased tau phosphorylation. Treating N2a cells with Aβ25–35 mimicked the changes of PP2Ac‐Yp307 and tau phosphorylation in N2a APPswe cells. Knockout of oestrogen receptor (ER) α or ERβ gave similar changes of PP2Ac‐Yp307 level and tau phosphorylation in the mouse brain. Taken together, these findings suggest that increased PP2A phosphorylation (Y307) can be mediated by Aβ deposition or oestrogen deficiency in the AD brain, and consequently compromise dephosphorylation of abnormally hyperphosphorylated tau, and lead to neurofibrillary tangle formation.
Exaggerated emotional behavior in mice heterozygous null for the sodium channel Scn8a (Nav1.6)
Authors: McKinney B. C. , Chow C. Y. , Meisler M. H. , Murphy G. G.
Published: March 2008

The Scn8a gene encodes the α‐subunit of Nav1.6, a neuronal voltage‐gated sodium channel. Mice homozygous for mutations in the Scn8a gene exhibit motor impairments. Recently, we described a human family with a heterozygous protein truncation mutation in SCN8A. Rather than motor impairment, neuropsychological abnormalities were more common, suggesting a role for Scn8a in a more diverse range of behaviors. Here, we characterize mice heterozygous for a null mutation of Scn8a (Scn8a+/−mice) in a number of behavioral paradigms. We show that Scn8a+/−mice exhibit greater conditioned freezing in the Pavlovian fear conditioning paradigm but no apparent abnormalities in other learning and memory paradigms including the Morris water maze and conditioned taste avoidance paradigm. Furthermore, we find that Scn8a+/−mice exhibit more pronounced avoidance of well‐lit, open environments as well as more stress‐induced coping behavior. Together, these data suggest that Scn8a plays a critical role in emotional behavior in mice. Although the behavioral phenotype observed in the Scn8a+/−mice only partially models the abnormalities in the human family, we anticipate that the Scn8a+/−mice will serve as a valuable tool for understanding the biological basis of emotion and the human diseases in which abnormal emotional behavior is a primary component.
Genetic dissection of quantitative trait locus for ethanol sensitivity in long‐ and short‐sleep mice
Authors: Bennett B. , Carosone‐Link P. , Beeson M. , Gordon L. , Phares‐Zook N. , Johnson T. E.
Published: March 2008

Interval‐specific congenic strains (ISCS) allow fine mapping of a quantitative trait locus (QTL), narrowing its confidence interval by an order of magnitude or more. In earlier work, we mapped four QTL specifying differential ethanol sensitivity, assessed by loss of righting reflex because of ethanol (LORE), in the inbred long‐sleep (ILS) and inbred short‐sleep (ISS) strains, accounting for approximately 50% of the genetic variance for this trait. Subsequently, we generated reciprocal congenic strains in which each full QTL interval from ILS was bred onto the ISS background and vice versa. An earlier paper reported construction and results of the ISCS on the ISS background; here, we describe this process and report results on the ILS background. We developed multiple ISCS for each Lore QTL in which the QTL interval was broken into a number of smaller intervals. For each of the four QTL regions (chromosomes 1, 2, 11 and 15), we were successful in reducing the intervals significantly. Multiple, positive strains were overlapped to generate a single, reduced interval. Subsequently, this reduced region was overlaid on previous reductions from the ISS background congenics, resulting in substantial reductions in all QTL regions by approximately 75% from the initial mapping study. Genes with sequence or expression polymorphisms in the reduced intervals are potential candidates; evidence for these is presented. Genetic background effects can be important in detection of single QTL; combining this information with the generation of congenics on both backgrounds, as described here, is a powerful approach for fine mapping QTL.
All Supply Chains Don't Flow Through: Understanding Supply Chain Issues in Product Recalls
Authors: Lyles Marjorie A. , Flynn Barbara B. , Frohlich Mark T.
Published: March 2008

Our paper conceptualizes and highlights the role of the supply chains in China's product recall problems. We raise questions about the interrelationships of the focal manufacturer and the supplier firms and the consequences of these relationships. We address some of the causes of the current situation, including a discussion of deep supply chains, the importance of relationships, the role of trust and the impact of cultural misunderstandings. We suggest many future research questions to further understand how the supply chain can cause or deter product recalls.
Facial Expression and Pain Assessment in the Pediatric Patient: The Primal Face of Pain
Authors: Schiavenato Martin
Published: March 2008

PURPOSE.  This paper aims to explore the role of facial expression in pediatric pain assessment. A comparison of tools employing facial expression methodology is presented. The concept of the primal face of pain (PFP) is introduced.

CONCLUSION.  The PFP offers an explanation to the utility and deficiency of facial pain scales and facial expression in pain assessment.

PRACTICE IMPLICATIONS.  The complexities of pain measurement should preclude the clinical application of untested instruments. For reported tools, a careful evaluation of the psychometric properties and the clinical context must precede application. The concept of the PFP warns against the application of facial pain scales as proxy measures in their intended population. Reliance on facial expression to assess pain in the school‐age child is imprecise.
Directions in Rural Development Policy – Lessons from Both Sides of the Atlantic Richtlinien für die ländliche Entwicklungspolitik – Beispiele von diesseits und jenseits des Atlantiks Les orientations de la politique de développement rural – Enseignements en provenance des deux côtés de l’Atlantique
Authors: Blandford David , Hill Berkeley
Published: March 2008

Directions in Rural Development Policy – Lessons from Both Sides of the Atlantic

A workshop comparing rural development policies in Europe and the US found differences in the social values that shape them. These include different attachments to place, concerns with lagging regions, and interests in the assessment of public interventions. There is also a difference in coverage. In the EU environmental and landscape issues form part of the CAP’s Rural Development Pillar, using agriculture as an instrument, whereas in the US these are handled by other policies, some of which can claim deeper historical roots. In the context of rural development policy, the EU attaches intrinsic value to the environment, while in the US the focus is more on economic spin‐offs from environmental quality. There are also differences in governance; a complete US view requires taking in Federal, State and local initiatives whereas in the EU a more organised framework is apparent. Nevertheless, when policy is viewed from a bottom‐up perspective many common features are found. Improving human and social capital and infrastructure are key factors to stimulating economic development on both sides of the Atlantic, though only some of these drivers form part of the CAP’s Pillar II. While in the EU the role of rural development is set to expand, this is far less certain in the US where the emphasis on agricultural support is likely to continue to dominate the political agenda.
Environment, Land Use and Amenities – the New Dimension of Rural Development Environnement, utilisation des terres et aménités – la nouvelle dimension du développement rural Umwelt, Landnutzung und landschaftliche Schönheit – die neue Dimension bei der Entwicklung des ländlichen Raums
Authors: McGranahan David A. , Thomson Kenneth J.
Published: March 2008

Environment, Land Use and Amenities – the New Dimension of Rural Development

While agriculture, environmental conditions, and rural development are concerns common to both sides of the Atlantic, their interrelationships are viewed quite differently. For the EU, agriculture is seen as a means of sustaining the countryside; keeping it attractive to tourists and prospective residents. Farmers are stewards of the land and as such a key to rural development. For the US, agriculture and the environment are seen in potential conflict. Most of the expenditure on conservation goes to keeping environmentally sensitive cropland out of production. At the national level at least, the appeal of the countryside is not seen as a means to rural development, so that conservation programs tend to be seen as a threat to rural development by reducing the use of local off‐farm services. Part of the difference in viewpoint may stem from the greater socio‐cultural significance of agricultural landscapes in the EU. However, recent research in the US suggests that landscape is important in attracting new rural residents and visitors and there is growing recognition on both sides of the Atlantic that the natural environment helps shape rural growth. More research is needed on the relationship between the environment and rural development as unsupported assumptions seem to underlie policies in both regions.
Structural Models and Binding Site Prediction of the C‐terminal Domain of Human Hsp90: A New Target for Anticancer Drugs
Authors: Sgobba Miriam , Degliesposti Gianluca , Ferrari Anna Maria , Rastelli Giulio
Published: March 2008

Heat shock protein 90 is a valuable target for anticancer drugs because of its role in the activation and stabilization of multiple oncogenic signalling proteins. While several compounds inhibit heat shock protein 90 by binding the N‐terminal domain, recent studies have proved that the C‐terminal domain is important for dimerization of the chaperone and contains an additional binding site for inhibitors. Heat shock protein 90 inhibition achieved with molecules binding to the C‐terminal domain provides an additional and novel opportunity to design and develop drugs. Therefore, for the first time, we have investigated the structure and the dynamic behaviour of the C‐terminal domain of human heat shock protein 90 with and without the small‐middle domain, using homology modelling and molecular dynamics simulations. In addition, secondary structure predictions and peptide folding simulations proved useful to investigate a putative additional α‐helix located between H18 and β20 of the C‐terminal domain. Finally, we used the structural information to infer the location of the binding site located in the C‐terminal domain by using a number of computational tools. The predicted pocket is formed by two grooves located between helix H18, the loop downstream of H18 and the loop connecting helices H20 and H21 of each monomer of the C‐terminal domain, with only two amino acids contributing from each middle domain.
Simulation Modeling as a Tool for Understanding the Landscape Ecology of Southern Pine Beetle Infestations in Southern Appalachian Forests
Authors: Cairns David Martin , Lafon Charles W. , Birt Andrew G. , Waldron John D. , Tchakerian Maria , Coulson Robert N. , Xi Weimin , Klepzig Kier
Published: March 2008

The forests of southeastern North America are influenced by a variety of disturbances including fire and insect outbreaks. In this paper, we discuss the role of disturbances in structuring forest landscapes with particular emphasis placed on the reciprocal interaction between forest structure and outbreaks of the southern pine beetle (Dendroctonus frontalisZimmermann). We highlight work in which we are currently involved to illustrate the importance and utility of using spatially explicit forest modeling as a tool for understanding forest–insect interactions and its potential role in determining management strategies.
The El Niño–Southern Oscillation and Global Precipitation
Authors: Curtis Scott
Published: March 2008

Our understanding of the relationship between the El Niño–Southern Oscillation (ENSO) phenomenon and global precipitation is reviewed from the early works of Sir Gilbert Walker to the latest research frontiers. ENSO is defined by large‐scale changes in the sea surface temperature and sea‐level pressure patterns of the Pacific Ocean. Rainfall follows the low (high) pressure (temperature) anomalies and subsequently impacts the global atmospheric circulation. ENSO contributes to global precipitation anomalies through teleconnections – changes in the Walker and Hadley circulations, oceanic Kelvin and Rossby waves, ‘atmospheric bridge’ mechanisms, and atmospheric Rossby wave trains – as observed with long‐term in situ measurements and recent satellite‐based analyses. Finally, some outstanding research questions are discussed. Is precipitation a useful predictor for ENSO? How does ENSO affect the probability density function of precipitation around the globe? What is the impact of global warming on the ENSO–precipitation relationship?
Variations in Base‐Flow Nitrate Flux in a First‐Order Stream and Riparian Zone1
Authors: Angier Jonathan T. , McCarty Gregory W.
Published: March 2008

Abstract:  Nonpoint source pollution, which contributes to contamination of surface waters, is difficult to control. Some pollutants, particularly nitrate (), are predominantly transmitted through ground water. Riparian buffer zones have the potential to remove contaminants from ground water and reduce the amount of that enters surface water. This is a justification for setting aside vegetated buffer strips along waterways. Many riparian zone hydrologic models assume uniform ground‐water flow through organic‐rich soil under reducing conditions, leading to effective removal of ground‐water prior to discharge into a stream. However, in a small first‐order stream in the mid‐Atlantic coastal plain, base‐flow generation was highly variable (spatially and temporally). Average base‐flow loads were greater in winter than summer, and higher during a wetter year than in dryer years. Specific sections of the stream consistently received greater amounts of high ground water than others. Areas within the riparian zone responsible for most of the exported from the watershed are termed “critical areas.” Over this 5‐year study, most of the exported during base flow originated from a critical area comprising less than 10% of the total riparian zone land area. Allocation of resources to address and improve mitigation function in critical areas should be a priority for continued riparian zone research.
Testing a Simple Field Method for Assessing Nitrate Removal in Riparian Zones1
Authors: Vidon Philippe , Dosskey Michael G.
Published: March 2008

Abstract:  Being able to identify riparian sites that function better for nitrate removal from groundwater is critical to using efficiently the riparian zones for water quality management. For this purpose, managers need a method that is quick, inexpensive, and accurate enough to enable effective management decisions. This study assesses the precision and accuracy of a simple method using three ground water wells and one measurement date for determining nitrate removal characteristics of riparian buffer zones. The method is a scaled‐down version of a complex field research method that consists of a large network of wells and piezometers monitored monthly for over two years. Results using the simplified method were compared to those from the reference research method on a date‐by‐date basis on eight sites covering a wide range of hydrogeomorphic settings. The accuracy of the three‐well, 1 day measurement method was relatively good for assessing nitrate concentration depletion across riparian zones, but poor for assessing the distance necessary to achieve a 90% nitrate removal and for estimating water and nitrate fluxes compared to the reference method. The simplified three‐well method provides relatively better estimates of water and nitrate fluxes on sites where ground‐water flow is parallel to the water table through homogeneous aquifer material, but such conditions may not be geographically widespread. Despite limited overall accuracy, some parameters that are estimated using the simplified method may be useful to water resource managers. Nitrate depletion information may be used to assess the adequacy of existing buffers to achieve nitrate concentration goals for runoff. Estimates of field nitrate runoff and buffer removal fluxes may be adequate for prioritizing management toward sites where riparian buffers are likely to have greater impact on stream water quality.
Occurrence of Volatile Organic Compounds in Aquifers of the United States1
Authors: Carter Janet M. , Lapham Wayne W. , Zogorski John S.
Published: March 2008

Abstract:  Samples of ambient ground water were collected during 1985‐2002 from 3,498 wells in 98 aquifer studies throughout the United States. None of the sampled wells were selected because of prior knowledge of nearby contamination. Most of these samples were analyzed for 55 volatile organic compounds (VOCs) to characterize their national occurrence. Volatile organic compounds were found in samples collected from 90 of the 98 aquifer studies. Occurrence frequencies of one or more VOCs for the 98 aquifer studies ranged from 0 to about 77% at an assessment level of 0.2 microgram per liter (μg/l). The aquifer studies with the largest occurrence frequencies were in southern Florida, southern New York, southern California, New Jersey, and Nevada. Trihalomethanes and solvents were the most frequently occurring VOC groups. Of the 55 VOCs included in this assessment, 42 occurred in at least one sample at an assessment level of 0.2 μg/l. Chloroform, perchloroethene, and methyl tert‐butyl ether were the most frequently occurring VOCs. Many factors, such as the hydrogeology of the aquifer, use of VOCs, land use, and the transport and fate properties of VOCs, affect the occurrence of VOCs in ground water.
The Role of Observer Variation in Determining Rosgen Stream Types in Northeastern Oregon Mountain Streams1
Authors: Roper Brett B. , Buffington John M. , Archer Eric , Moyer Chris , Ward Mike
Published: March 2008

Abstract:  Consistency in determining Rosgen stream types was evaluated in 12 streams within the John Day Basin, northeastern Oregon. The Rosgen classification system is commonly used in the western United States and is based on the measurement of five stream attributes: entrenchment ratio, width‐to‐depth ratio, sinuosity, slope, and substrate size. Streams were classified from measurements made by three monitoring groups, with each group fielding multiple crews that conducted two to three independent surveys of each stream. In only four streams (33%) did measurements from all crews in all monitoring groups yield the same stream type. Most differences found among field crews and monitoring groups could be attributed to differences in estimates of the entrenchment ratio. Differences in entrenchment ratio were likely due to small discrepancies in determination of maximum bankfull depth, leading to potentially large differences in determination of Rosgen’s flood‐prone width and consequent values of entrenchment. The result was considerable measurement variability among crews within a monitoring group, and because entrenchment ratio is the first discriminator in the Rosgen classification, differences in the assessment of this value often resulted in different determination of primary stream types. In contrast, we found that consistently evaluated attributes, such as channel slope, rarely resulted in any differences in classification. We also found that the Rosgen method can yield nonunique solutions (multiple channel types), with no clear guidance for resolving these situations, and we found that some assigned stream types did not match the appearance of the evaluated stream. Based on these observations we caution the use of Rosgen stream classes for communicating conditions of a single stream or as strata when analyzing many streams due to the reliance of the Rosgen approach on bankfull estimates which are inherently uncertain.
Utility of Gridded Rainfall for IHACRES Daily River Flow Predictions in Southern California Watersheds1
Authors: Hope Allen , Decker Jordan , Jankowski Piotr
Published: March 2008

Abstract:  Studies to regionalize conceptual hydrologic models generally require rainfall and river flow data from multiple watersheds. Besides the considerable time (cost) to assemble and process rainfall data for many watersheds, investigators often need to choose from a number of candidate gauges, subjectively weighing the relative importance of proximity and elevation to select a representative rainfall dataset. The Unified Raingauge Dataset (URD) is a gridded daily rainfall dataset that covers the conterminous United States at 0.25 × 0.25 degrees spatial resolution and is available from 1948 to present. The objective of this study was to determine whether uncertainty in daily river flow predictions using the conceptual hydrologic model IHACRES in small to moderate size watersheds (50‐400 km2) in southern California would increase if URD gridded rainfall data were used in place of single rain gauge data to calibrate the model. Rain gauge data were obtained from the gauge nearest the watershed centroid and the gauge closest in elevation to the watershed mean elevation. Results from 20 randomly selected watersheds indicated that IHACRES calibration performance was similar using rainfall data from the URD grids and rain gauge data. There was some evidence of greater uncertainties associated with the URD calibrations in areas where topography may affect rainfall amounts. In contrast to the URD data, monthly gridded data produced by the Parameter‐Elevation Regressions on Independent Slopes Model (PRISM) includes adjustments for elevation and produces gridded values at a finer spatial resolution (4 km2). A limited test on two watersheds demonstrated that scaling the URD daily rainfall estimates to match the PRISM monthly values may improve rainfall estimates and model simulation performance.
Water Footprint of the Palestinians in the West Bank1
Authors: Nazer Dima W. , Siebel Maarten A. , Van der Zaag Pieter , Mimi Ziad , Gijzen Huub J.
Published: March 2008

Abstract:  Water in the West Bank of Palestine is a key issue due to its limited availability. Water is used from own sources for domestic, industrial, and agricultural purposes. Moreover, water is consumed in its virtual form through consumption of imported goods, such as crops and livestock, the production of which used water in the country of production. In addition, wastewater in many parts of the West Bank is disposed off without treatment into the wadis, deteriorating the quality of the water resources in the area and, therefore, further reducing the quantity of good quality water available. This paper calculates the water footprint for the West Bank. The consumption component of the water footprint of the West Bank was found to be 2,791 million m3/year. Approximately 52% of this is virtual water consumed through imported goods. The West Bank per capita consumption component of the water footprint was found to be 1,116 m3/cap/year, while the global average is 1,243 m3/cap/year. Out of this number 50 m3/cap/year was withdrawn from water resources available in the area. Only 16 m3/cap/year (1.4%) was used for domestic purposes. This number is extremely low and only 28% of the global average and 21% of the Israeli domestic water use. The contamination component of the water footprint was not quantified but was believed to be many times larger than the consumption component. According to the official definition of water scarcity, the West Bank is suffering from a severe water scarcity. Therefore, there is a need for a completely new approach towards water management in the West Bank, whereby return flows are viewed as a resource and that is geared towards a conservation oriented approach of “use, treat, and reuse.”
Modeling Streams and Hydrogeomorphic Attributes in Oregon From Digital and Field Data1
Authors: Clarke Sharon E. , Burnett Kelly M. , Miller Daniel J.
Published: March 2008

Abstract: Managers, regulators, and researchers of aquatic ecosystems are increasingly pressed to consider large areas. However, accurate stream maps with geo‐referenced attributes are uncommon over relevant spatial extents. Field inventories provide high‐quality data, particularly for habitat characteristics at fine spatial resolutions (e.g., large wood), but are costly and so cover relatively small areas. Recent availability of regional digital data and Geographic Information Systems software has advanced capabilities to delineate stream networks and estimate coarse‐resolution hydrogeomorphic attributes (e.g., gradient). A spatially comprehensive coverage results, but types of modeled outputs may be limited and their accuracy is typically unknown. Capitalizing on strengths in both field and regional digital data, we modeled a synthetic stream network and a variety of hydrogeomorphic attributes for the Oregon Coastal Province. The synthetic network, encompassing 96,000 km of stream, was derived from digital elevation data. We used high‐resolution but spatially restricted data from field inventories and streamflow gauges to evaluate, calibrate, and interpret hydrogeomorphic attributes modeled from digital elevation and precipitation data. The attributes we chose to model (drainage area, mean annual precipitation, mean annual flow, probability of perennial flow, channel gradient, active‐channel width and depth, valley‐floor width, valley‐width index, and valley constraint) have demonstrated value for stream research and management. For most of these attributes, field‐measured, and modeled values were highly correlated, yielding confidence in the modeled outputs. The modeled stream network and attributes have been used for a variety of purposes, including mapping riparian areas, identifying headwater streams likely to transport debris flows, and characterizing the potential of streams to provide high‐quality habitat for salmonids. Our framework and models can be adapted and applied to areas where the necessary field and digital data exist or can be obtained.
Taxonomical notes on the Chilean Cruciferae
Authors: Ravenna Pierfelice
Published: March 2008

The taxonomic status of some Chilean Cruciferae is elucidated, and new combinations in the genera Stenodraba Sch. and Hollermayera Sch. are established. Additionally a new section, Elatia, and two specific names to replace illegitimate binomials in Stenodraba are proposed.
The genus Calceolaria in NW South America. VI. The sections Urticopsis, Lobatae and Micranthera
Authors: Molau Ulf
Published: March 2008

Three sections of Calceolaria (Scrophulariaceae) in NW South America are revised, viz. sect. Urticopsis (8 species in the area), Lobatae (4), and Micranthera (2). Sect. Urticopsis is characterized by herbaceous, ovate, petiolate leaves and white to buffish pubescence. Sect. Lobatae is characterized by lobate, petiolate leaves and white to greyish white pubescence. Sect. Micranthera comprises small herbs with a weedy habit, characterized by small anthers and unusually long filaments. Three new species are described, viz. C. obtusa, C. trichanthera, and C. adenocalyx (all in sect. Urticopsis), and one new combination is made, viz. C. penlandii ssp. puraceensis (sect. Urticopsis). Chromosome numbers (all 2n = 36) are reported for C. lamiifolia, C. obtusa, C. penlandii ssp. penlandii, and C. dichotoma.
The genus Calceolaria in NW South America VII. The section Zygophylla
Authors: Molau Ulf
Published: March 2008

Sect. Zygophylla of Calceolaria (Scrophulariaceae) in NW South America is revised. It is characterized by connate leaves with winged petioles, and most of the species have intercalary inflorescences. Fourteen species are recognized in the investigated area, one of which is described as new, viz. C. zamorana. Two new combinations are made, viz. C. nevadensis ssp. meridensis (Pennell) Molau and C. purpurascens (Kranzlin) Molau. The chromosome number 2n = 36 is reported for six of the species, viz. C. calycina, C. dilatata, C. grandiflora, C. lanata, C. lojensis, and C. trilobala. The species of sect. Zygophylla are completely interfertile, and sympatric species are isolated by external barriers, e.g. pollination and habitat ecology. Several cases of natural hybridization and introgression are reported.
The disjunct distribution of Carex peregrina confirmed
Authors: Thulin Mats
Published: March 2008

Carex peregrina Link, currently considered an endemic of the Azores and Madeira, is shown to have a disjunct distribution with occurrences also in the Afromontane Region of Ethiopia and E Africa.
Revision of the Thalia geniculata complex (Marantaceae)
Authors: Andersson Lennart
Published: March 2008

Within the Thalia geniculata complex, which corresponds to subgen. Arthrothalia Schum., three species have been recognized in recent taxonomic literature, viz. T. geniculata L., T. trichocalyx Gagnepain, and T. welwitschii Ridley. The variation pattern within this complex has been analyzed with the aid of pictorialized scatter diagrams and it is concluded that the entire complex is made up of a single polymorphic species, of which no further subdivision is justified. T. geniculata is redescribed and full synonymy is given.
Scabropezia, a new genus of Pezizaceae (Pezizales)
Authors: Dissing Henry , Pfister Donald H.
Published: March 2008

Scabropezia gen. nov., with globose spores, is described with two species, viz. the type species S. scabrosa (Cooke) comb, nov., and S. flavovirens (Fuck.) comb. nov. The relationship to the globose–spored genera Plicaria Fuck, emend. Boud. and Pachyphloeus Tul. and to the genus Peziza L. ex St.–Amans is discussed. A key for the treated taxa is provided.
Typification and delimitation of Omphalina Quel
Authors: Lange Morten
Published: March 2008

The typification of the genus Omphalina Quél, is discussed. There is conclusive evidence to prove that the type should be Omphalina umbellifera (L. ex Fr.) Quél. =O. ericetorum (Fr. ex Fr.) M. Lange and not a species now referred to as O. pseudoandrosacea (Bull, ex St.–Amans) Mos. =O. grisella (Weinm.) Mos. A neotype for O. ericetorum is selected. The recent classifications of Omphalina and related genera are not convincing, and a rearrangement of Gerronema, Phaeotellus, Ric–kenella, and Haasiella inside genus Omphalina is proposed. A series of corresponding new combinations are made or validated.
Ascomycetes from Northern Thailand
Authors: Schumacher Trond
Published: March 2008

12 pyrenomycetes and 22 discomycetes are recorded from the Chiang Mai Province of Northern Thailand. 25 species are new to Thailand. Pulvinula anthracobia Schum. is described as new, and Xylaria scopiformis (Mont, ex Joly) Schum. comb. nov. is proposed.
Isatis vermia sp.nov. from north central Greece Materials for the Mountain Flora of Greece, 14
Authors: Papanicolaou Kostas
Published: March 2008

Isatis vermia Papanicolaou sp. nov. is described from Mt Vermion in north central Greece. It is an autumn–flowering species related to J. tinctoria L. The chromosome number is 2n = 28.