bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribution of oligosaccharides to protection of the H,K‐ATPase β‐subunit against trypsinolysis
Authors: Crothers James M. , Asano Shinji , Kimura Tohru , Yoshida Ayumi , Wong Aline , Kang Jung Wook , Forte John G.
Published: August 2004

The proton‐pumping H+,K+‐adenosinetriphosphatase (H,K‐ATPase), responsible for acid secretion by the gastric parietal cell, faces a harshly acidic environment, with some pepsin from neighboring chief cells, at its luminal surface. Its large catalytic α‐subunit is mostly oriented cytoplasmically. The smaller β‐subunit (HKβ), is mainly extracellular, with one transmembrane domain and a small cytoplasmic domain. Seven N‐linked oligosaccharides in the extracellular domain of HKβ are thought to contribute to protection of the H,K‐ATPase, since previous work has shown that their complete removal, by peptide N‐glycosidase F (PNGase F), greatly increased susceptibility of HKβ to proteolysis. The possibility of graded protection by different numbers of oligosaccharides was investigated here with the use of mutant HKβ cDNA, having various N‐glycosylation sites mutated (Asn to Gln), transfected into HEK‐293 cells. Membrane preparations, two days after transfection, were solubilized in 1% Triton X‐100 and subjected to trypsinolysis (pH 8, 37°C, trypsin:protein 1:10–1:25). Relative amounts of HKβ remaining after 20 min trypsin were determined, after sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and probing of Western blots with an antibody to the HKβ extracellular domain, by chemiluminescent development of blots and densitometry of resulting films. Maturely glycosylated HKβ was made significantly more susceptible to trypsin than wild type when at least five oligosaccharides were deleted, while the high‐mannose form (pre‐β), from the endoplasmic reticulum, became significantly more susceptible than wild‐type pre‐β with removal of only two or more oligosaccharides. For each mutant, and wild type, pre‐β was consistently more susceptible than the mature form. While the number, and kind, of oligosaccharides seem to affect protection for HKβ against trypsinolysis, other aspects of protein maturation, including proper folding of peptide domains and possible subtle alterations of conformation during Golgi processing, are also likely to contribute to this protection.
Detection of CFTR mutations using temporal temperature gradient gel electrophoresis
Authors: Wong Lee‐Jun C. , Alper Özgül M.
Published: August 2004

Cystic fibrosis (CF), caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, is one of the most common autosomal recessive diseases with variable incidences and mutation spectra among different ethnic groups. Current commercially available mutation panels designed for the analysis of known recurrent mutations have a detection rate between 38 to 95%, depending upon the ethnic background of the patient. We describe the application of a novel mutation detection method, temporal temperature gradient gel electrophoresis (TTGE), to the study of the molecular genetics of Hispanic CF patients. TTGE effectively identified numerous rare and novel mutations and polymorphisms. One interesting observation is that the majority of the novel mutations are splice site, frame shift, or nonsense mutations that cause severe clinical phenotypes. Our data demonstrate that screening of the 27 exons and intron/exon junctions of the CFTR gene by TTGE greatly improves the molecular diagnosis of Hispanic CF patients.
Detection of mitochondrial DNA mutations using temporal temperature gradient gel electrophoresis
Authors: Wong Lee‐Jun C. , Chen Tian‐Jian , Tan Duan‐Jun
Published: August 2004

Mitochondrial disorders are a group of clinically and genetically heterogeneous diseases. Common recurrent mitochondrial DNA (mtDNA) point mutations account for the molecular defects of a small proportion of patients. In order to identify mtDNA mutations, comprehensive mutational analysis of the entire mitochondrial genome is necessary. We developed the temporal temperature gradient gel electrophoresis (TTGE) method to screen for mutations in mtDNA. The entire mitochondrial genome was amplified using 32 pairs of overlapping primers followed by TTGE analysis of the DNA fragments. TTGE method was first validated on 200 DNA fragments containing known mutations or polymorphisms. On TTGE, homoplasmic nucleotide substitutions show a single band shift and heteroplasmic mutations show multiple banding patterns. The known mutations or polymorphisms were correctly identified. TTGE was then used to screen for unknown mutations in the mitochondrial genome. DNA banding patterns, deviated from wild‐type, suggestive of either homoplasmic or heteroplasmic mutations, were followed by direct DNA sequencing to identify the mutations. Numerous mutations and polymorphisms were detected. The results demonstrated that TTGE detects and distinguishes heteroplasmic mutations from homoplasmic polymorphisms. It also detects heteroplasmic changes in the background of a homoplasmic polymorphism. Overall, TTGE was proven to be a simple, rapid, sensitive, and effective mutation detection method.
Cross‐reactivity of antibodies to actin‐ depolymerizing factor/cofilin family proteins and identification of the major epitope recognized by a mammalian actin‐depolymerizing factor/cofilin antibody
Authors: Shaw Alisa E. , Minamide Laurie S. , Bill Christine L. , Funk Janel D. , Maiti Sankar , Bamburg James R.
Published: August 2004

Members of the actin‐depolymerizing factor (ADF)/cofilin family of proteins are expressed in all eukaryotic cells. In higher vertebrates, cells often express as many as three different ADF/cofilin genes and each of these proteins may be phosphorylated on serine 3, giving rise to up to six different species. Also, many avian, amphibian, and invertebrate systems have been useful in studying different aspects of ADF/cofilin function. Antibodies have been prepared against different members of the ADF/cofilin family, but no systematic examination of their cross‐reactivity has been reported. Although ADF and cofilins within a single vertebrate species have about a 70% sequence homology, antibodies often differentiate between these proteins. Here, Western blotting was used with chemiluminescence substrates of different sensitivities to determine the relative immunoreactivities of different polyclonal rabbit antibodies and a mouse monoclonal antibody to purified ADF/cofilins from plants, protists, nematodes, insects, echinoderms, birds, and mammals. From immunocross‐reactivities and sequence alignments, the principal epitope in mammalian ADF and cofilin‐1 recognized by an antibody raised against avian ADF was identified. The specificity of an antibody to the phosphopeptide epitope of metazoan ADF/cofilins was confirmed by two‐dimensional (2‐D) immunoblot analysis. Futhermore, this bank of antibodies was used to identify by Western blotting a putative member of the ADF/cofilin family in the sea slug, Aplysia californica.
Transaction allocation symbolic analysis method
Authors: Škokljev Ivan , Maksimović Viktor
Published: August 2004

Transaction allocation aims at pin‐pointing the responsibility and incurred costs for the transactions in the transmission network operating in the open access mode. The basic question for the operation and planning in this changing industry is who is paying for what and through which line? As an answer to that problem, this paper offers the transaction allocation symbolic analysis based method. The symbolic analysis approach here introduces a bilateral transaction of active power as a compact, analytical expression, which could further be exposed to sensitivity analysis as with linear networks. The multilateral transaction analysis is also conveyed. The novel approach is demonstrated on a five‐node popular test network. Copyright © 2004 John Wiley & Sons, Ltd.
Current controlled line converter using direct torque control method
Authors: Tarkiainen Antti , Pöllänen Riku , Niemelä Markku , Pyrhönen Juha
Published: August 2004

The control system of a current controlled line converter is implemented using the direct torque control (DTC) method. Implementation of the converter flux linkage orientated control system combines the DTC method with the conventional field orientated vector control principle. The same physical structure of the control system as in DTC motor control can be used with the line converter without extra measurements. Both L‐ and LCL‐topologies are used as line filters. Experimental results demonstrate the validity and the high dynamic performance of the control system. Copyright © 2004 John Wiley & Sons, Ltd.
Hydro turbine speed control using robust cascade governor controllers
Authors: Eker İlyas
Published: August 2004

This paper presents a cascade control approach to the design of governors for speed control of hydro turbines in power generation units. The key issues include the problems of model uncertainty, inner and outer loop disturbances, load rejections and attenuation of measurement noise. Gate position deviation signal is used as a supplementary inner loop manipulated variable in the proposed cascade control. The effect of water hammer, travelling waves and inelastic water penstocks is included in the hydro turbine model. The polynomial H∞ design method is used to design cascade governor controllers. Dynamic weighting functions of the H∞ design method provide the required control actions. A cascade robust governor ensures that the overall system remains asymptotically stable for all permissible norm‐bounded uncertainties and system oscillations. The results presented in the time and frequency domains are compared with conventional PID and PID cascade designs. The results show that the performance of the system is significantly improved by the proposed cascade governor design. Copyright © 2004 John Wiley & Sons, Ltd.
Load estimation for distribution systems with minimum information
Authors: Borozan Vesna P. , Rajakovic Nikola L. J.
Published: August 2004

The operation of distribution systems requires a rather high number of planned or forced switching operations. In order to prepare them, it is necessary to estimate loads at different levels in the system. This paper proposes a load estimation method for distribution systems with minimum information available. The purpose of the load estimation method presented in this paper is the economic and efficient use of the available remote measurements in the distribution system considering typical measurements from the past and knowledge of load composition and load behaviour at the distribution transformers' level. The method is load‐flow based, and its capability, efficiency and accuracy are demonstrated by application on a practical distribution system. Copyright © 2004 John Wiley & Sons, Ltd.
Observing the performance of distribution systems with embedded generators
Authors: Ciric Rade M. , Padilha‐Feltrin Antonio , Denis Iara Fernanda E. D.
Published: August 2004

In this paper, a multi‐objective approach for observing the performance of distribution systems with embedded generators in the steady state, based on heuristic and power system analysis, is proposed. The proposed hybrid performance index describes the quality of the operating state in each considered distribution network configuration. In order to represent the system state, the loss allocation in the distribution systems, based on the Z‐bus loss allocation method and compensation‐based power flow algorithm, is determined. Also, an investigation of the impact of the integration of embedded generators on the overall performance of the distribution systems in the steady state, is performed. Results obtained from several case studies are presented and discussed. Copyright © 2004 John Wiley & Sons, Ltd.
A novel three‐phase time domain load modelling technique using instantaneous symmetrical components
Authors: Gul O. , Kaypmaz A. , Tanrioven M.
Published: August 2004

This paper presents a new time domain load modelling technique based on the method of Instantaneous Symmetrical Components (ISC) for three‐phase unbalanced and distorted power system loads. ISC is used here to obtain instantaneous symmetrical voltage and current components and these components are used in the calculation of the symmetrical component model parameters, resistance (R(0,1,2)), inductance (L(0,1,2)), capacitance (C(0,1,2)) and a harmonic instantaneous current source (j(t)), which are all connected in parallel. The results cover four cases of the system operation and the load parameters are found for each case, even in the presence of harmonic distortion. Consequently, it is shown that the developed method is a very powerful modelling technique to model time varying, unbalanced and distorted three‐phase loads, such as general loads: i.e. residential and commercial buildings. Copyright © 2004 John Wiley & Sons, Ltd.
Constrained economic dispatch by deterministic tabu search approach
Authors: Ongsakul W. , Dechanupaprittha S. , Ngamroo I.
Published: August 2004

This paper presents a deterministic tabu search (DTS) algorithm for solving ramp rate constrained economic dispatch (ED) problems for generating units with non‐monotonically and monotonically increasing incremental cost (IC) functions. The proposed DTS uses proper tabu list, aspiration level, and reference unit rotation strategy to yield a high‐quality solution. The developed DTS is tested on the systems with the number of generating systems in the range of 10 to 80 units over the entire dispatch periods. The obtained solutions are near the optimal solutions of the unconstrained DTS (UDTS) and more economical than those obtained from the micro‐genetic algorithm based on migration and merit order loading solutions (MGAM‐MOL), the genetic algorithm based on simulated annealing solutions (GA‐SA), simulated annealing (SA), genetic algorithm (GA), and merit order loading (MOL) approaches, thereby leading to substantial generator fuel cost savings. Furthermore, DTS can be easily parallelized to compromise the solution quality and computational speed‐up for the best performance. Copyright © 2004 John Wiley & Sons, Ltd.
Composition of the volatile constituents of the aerial parts of an endemic plant of Ivory Coast, Monanthotaxis capea (E.G. & A. Camus) Verdc
Authors: Mevy J. P. , Bessiere J. M. , Pelissier Y. , Masotti V. , Ruzzier M. , Rabier J. , Viano J.
Published: August 2004

Both essential oils and solvent extracts of leaves, stems and fruits of Monanthotaxis capea were studied by GC and GC‐MS. The main constituents identiﬁed in the different organs studied were phenylbutane derivatives in range of 97–57%. While (E)‐4‐phenylbut‐3‐en‐2‐ol was shown as the main component of the hydrodistillates, the parent ester (E)‐4‐phenylbut‐3‐en‐2‐yl acetate was shown as the major compound of the solvent extracts. Thus some of the phenylbutane derivatives in the hydrodistillates of the aerial parts of Monanthotaxis capea would appear to be artifacts. Copyright © 2004 John Wiley & Sons, Ltd.
Chemical composition of the leaf and fruit essential oils of Murraya paniculata (L.) Jack. (Syn. Murraya exotica Linn.)
Authors: Olawore Nureni O. , Ogunwande Isiaka A. , Ekundayo Olusegun , Adeleke Kasali A.
Published: August 2004

The essential oils from the leaves and fruits of Murraya paniculata (L.) Jack. grown in Nigeria were analysed by means of gas chromatograph and gas chromatograph interfaced with mass spectrometry. Both oils were rich in sesquiterpenoids. The principal constituents of the leaf oil were β‐cyclocitral (22.9%), methyl salicylate (22.4%), trans‐nerolidol (11.7%), α‐cubebene (7.9%), (−)‐cubenol (6.8%), β‐cubebene (5.8%) and isogermacrene (5.7%). The most abundant constituent of the fruit essential oil was β‐caryophyllene (43.4%). Other major components were (−)‐zingiberene (18.9%), germacrene D (8.3%), α‐copaene (5.5%) and α‐humulene (5.1%). The compositions of both oils varied qualitatively and quantitatively. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of harvest time on the yield and composition of Tunisian myrtle oils
Authors: Jamoussi Bassem , Romdhane Mehrez , Abderraba Abdelmenef , Hassine Bechir Ben , Gadri Abdellatif EL
Published: August 2004

The yield and composition variation of the leaf essential oil from Myrtus communis L, an aromatic wild plant which grows in the area of Tabarka (north‐western Tunisia) were investigated. Essential oil was obtained by steam distillation at atmospheric pressure of the dried, ground herbal material. The yield of essential oil reached a peak at the beginning of the ﬂowering stage (0.54%) and a minimum after the ﬂowering period (0.27%). Thirty‐nine components were identiﬁed in the essential oil by GC and GC–MS. The major constituent of the oil was found to be a‐pinene. Copyright © 2004 John Wiley & Sons, Ltd.
Untangling Gordian knots: improving tuberculosis control through the development of ‘programme theories’
Authors: Coker R. , Atun R. , McKee M.
Published: August 2004

We argue that if the lessons from tuberculosis control programmes are to be drawn effectively then a more nuanced understanding is needed that takes account of the complex health system environment within which they sit. We suggest that a conceptual framework that draws upon the World Health Organization's DOTS strategy can be harnessed to assist the systematic analysis of programmes in a way that links this vertical, disease specific strategy to horizontal health system factors so that comparisons can be made. This multi‐disciplinary, multi‐method approach to the evaluation builds upon the work of others including Pawson and Tilley and their ‘programmes theories’. This work has informed the application of an evaluation toolkit which has been successfully applied in a number of settings and assisted in the sustainable implementation of a DOTS strategy in Russia. Copyright © 2004 John Wiley & Sons, Ltd.
A model for effective involvement of private medical practitioners in TB care
Authors: Zafar Ullah A. N. , Lubben Marianne , Newell James N.
Published: August 2004

The purpose of this paper is to propose a process to help to develop a new model for partnerships in tuberculosis (TB) control, based on experiences to date. We start by identifying the essential service components needed in order to deliver quality care. Secondly, we identify the main partners in a collaboration or partnership. We describe a generic model linking the partners and the components. This model is then used to describe and analyse successful partnerships currently in existence, identifying those features that produced a successful outcome regarding increased access, coverage and quality for TB control. Finally, we illustrate how the process and generic model has been used to develop a locally appropriate model for partnerships in TB control, taking Bangladesh as our example. Copyright © 2004 John Wiley & Sons, Ltd.
Factors affecting the implementation of health legislation and its impact on the rural poor in China: A case study of implementation of the maternal and infant health care law in two poor counties
Authors: Tolhurst Rachel , Zhang Tuohong , Yang Hui , Gao Jun , Tang Shenglan
Published: August 2004

This paper presents and discusses a case study of health legislation in China. In the transition to a market economy, legislation has been developed to offset the weakening in the central planning mechanism and political control that have historically influenced the behaviour of institutions and individuals in the Ministry of Health. There has been relatively little empirical examination of the implementation and impact of legislation as a tool for influencing health service provision in low‐income countries. The study aimed to contribute towards filling this gap by exploring the factors affecting the implementation and impact of the Maternal and Infant Health Care Law, through a case study of two poor, rural counties in Chongqing municipality, China. The study found that key local actors perceive health legislation to be an important tool for safeguarding access to essential health care. However, the implementation of health legislation is inevitably a political process. The study illustrates the difficulties involved in efforts to influence provider behaviour through a national level legislative framework in a situation of decentralization of control over those providers, due to extreme regional variation in economic situations and limited resource inputs from the centre. Lessons are drawn for Chinese and international policy makers. Copyright © 2004 John Wiley & Sons, Ltd.
Reduction in experimental peridural adhesion with the use of a crosslinked hyaluronate/collagen membrane
Authors: Shih Hsin‐Nung , Fang Jen‐Feng , Chen Jui‐Hsiang , Yang Chiung‐Lin , Chen Yu‐Hua , Sung Tseng‐Hwa , Shih Lih‐Yuann
Published: August 2004

The research goals were to fabricate a crosslinked hyaluronate (HA)/collagen membrane and study its efficacy in preventing peridural adhesion. Different weight ratios of HA/collagen membranes crosslinked with carbodiimide were tested for biocompatibility and biodegradability first. Forty‐eight adult New Zealand white rabbits underwent an L6 laminectomy. Sixteen rabbits each received a weight ratio of HA/collagen = 60/40 membrane (Membrane A) or a 40/60 membrane (Membrane B) on the exposed dura. The last 16 rabbits received no treatment and served as controls. No adverse reaction of the membranes was noted. Magnetic resonance images revealed a hyposignal space between the dura and the scar tissues at Membrane B‐treated laminectomy site 3 months after surgery. Histological examination showed that the amount of scarring decreased with time in all groups. Amount of scarring decreased significantly at laminectomy sites treated with either membrane. Compared with the control group, the extent of peridural adhesion decreased significantly in the Membrane B‐treated group at 3 months after surgery; while it decreased substantially, but not significantly, in the Membrane A‐treated group. The carbodiimide‐crosslinked HA/collagen membrane is a safe and effective antiadhesive material in vivo. When placed onto the laminectomy site, the membrane with a weight ratio of HA/collagen = 40/60 appears to reduce peridural scar adhesion. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 421–428, 2004
Regulation of fibrogenic/fibrolytic genes by platelet‐derived growth factor C, a novel growth factor, in human dermal fibroblasts
Authors: Jinnin Masatoshi , Ihn Hironobu , Mimura Yoshihiro , Asano Yoshihide , Yamane Kenichi , Tamaki Kunihiko
Published: August 2004

Platelet‐derived growth factor (PDGF) is a potent mitogenic and chemotactic cytokine, and PDGF‐C is a novel growth factor belonging to the PDGF family. In this study, to determine whether this growth factor can contribute to fibrosis and tissue remodeling, we examined the effect of PDGF‐CC on the expression of fibrogenic/fibrolytic genes such as type I collagen, fibronectin (FN), matrix metalloproteinases (MMPs), and their inhibitors (TIMPs) in normal human dermal fibroblasts in vitro. PDGF elevated the levels of MMP‐1 or TIMP‐1 protein as well as mRNA, whereas this cytokine had no influence on the expression of type I collagen, FN, or TIMP‐2. PDGF‐CC also increased the levels of MMP‐1 catalytic activity in the cultured media and mRNA expression, which was paralleled that on the levels of promoter activation. Additionally, PDGF‐CC induced the mitogenic and migratory activity of human dermal fibroblasts in a dose‐dependent manner. On the other hand, we also determined the specificity of the inhibitory effect of monoclonal antibodies against PDGF‐CC generated by immunizing balb/c mice with recombinant human PDGF‐CC. This antibody could inhibit the regulatory effects of MMP‐1 or TIMP‐1 synthesis as well as the mitogenic effects on human dermal fibroblasts induced by PDGF‐CC, whereas this antibody did not affect those induced by other PDGF forms such as PDGF‐AA, ‐AB, or ‐BB. These results suggest that this cytokine plays a role in the tissue remodeling. © 2004 Wiley‐Liss, Inc.
The use of nutshell carbons in drinking water filters for removal of chlorination by‐products
Authors: Ahmedna Mohamed , Marshall Wayne E , Husseiny Abdo A , Goktepe Ipek , Rao Ramu M
Published: August 2004

Chlorination of drinking water is a common practice, used by numerous municipalities in the United States (US) to safeguard their water supplies. However, the chlorine used can chemically react with organic components in the drinking water to produce unwanted chlorination by‐products. The objective of this investigation was to evaluate the use of granular activated carbon produced from nutshells (almond, English walnut, pecan) in a point‐of‐use (POU) water filtration system designated ‘Envirofilter’ and to determine its efficacy in removing select, potentially carcinogenic chlorination by‐products, namely the trihalomethanes (THMs) bromodichloromethane, bromoform and dibromochloromethane. The POU water filtration system that contained the nutshell‐based carbons was designated ‘Envirofilter’ and adsorption efficiencies of this system were compared to that of four commercially available POU home water filter systems, namely, BRITA, Omni Filter, PŪR and Teledyne Water Pik. Eight different ‘Envirofilters’ were constructed of individual or binary mixtures of carbons produced from acid‐activated almond or pecan shells and steam‐activated pecan or walnut shells and evaluated for adsorption of the three chlorination by‐products. The results indicate that only two of the eight ‘Envirofilters’ failed to remove more THMs than the commercial POU systems. In both cases, these filters contained carbons with either 100% acid‐activated almond shells or 100% acid‐activated pecan shells. All six of the other filters contained carbons with either 50% or 100% steam‐activated pecan shells or steam‐activated walnut shells. Therefore, ‘Envirofilters’ appeared to depend on the presence of steam‐activated nutshell carbons for their success. The six effective ‘Envirofilters’ reduced THM levels to below the Maximum Contaminant Levels (MCL) required by the US Environmental Protection Agency (US EPA). Based on these results, these six ‘Envirofilters’ may be considered as a replacement for existing commercial filter systems because of their efficacy and projected cost. Copyright © 2004 Society of Chemical Industry
Protective effect of green tea polyphenol EGCG against neuronal damage and brain edema after unilateral cerebral ischemia in gerbils
Authors: Lee Hyung , Bae Jae Hoon , Lee Seong‐Ryong
Published: August 2004

Previous studies have demonstrated that a green tea polyphenol, (−)‐epigallocatechine gallate (EGCG), has a potent free radical scavenging and antioxidant effect. Glutamate leads to excitotoxicity and oxidative stress, which are important pathophysiologic responses to cerebral ischemia resulting in brain edema and neuronal damage. We investigated the effect of EGCG on excitotoxic neuronal damage in a culture system and the effect on brain edema formation and lesion after unilateral cerebral ischemia in gerbils. In vitro, excitotoxicity was induced by 24‐hr incubation with N‐methyl‐D‐aspartate (NMDA; 10 μM), AMPA (10 μM), or kainate (20 μM). EGCG (5 μM) was added to the culture media alone or with excitotoxins. We examined malondialdehyde (MDA) level and neuronal viability to evaluate the effect of EGCG. In vivo, unilateral cerebral ischemia was induced by occlusion of the right common carotid artery for 30, 60, or 90 min and followed by reperfusion of 24 hr. Brain edema, MDA, and infarction were examined to evaluate the protective effect of EGCG. EGCG (25 or 50 mg/kg, intraperitoneally) was administered twice, at 30 min before and immediately after ischemia. EGCG reduced excitotoxin‐induced MDA production and neuronal damage in the culture system. In the in vivo study, treatment of gerbils with the lower EGCG dose failed to show neuroprotective effects; however, the higher EGCG dose attenuated the increase in MDA level caused by cerebral ischemia. EGCG also reduced the formation of postischemic brain edema and infarct volume. These results demonstrate EGCG may have future possibilities as a neuroprotective agent against excitotoxicity‐related neurologic disorders such as brain ischemia. © 2004 Wiley‐Liss, Inc.
Nitrogen mineralization from mature bio‐waste compost in vineyard soils. I. Long‐term laboratory incubation experiments
Authors: Nendel Claas , Reuter Stephan , Kubiak Roland , Nieder Rolf
Published: August 2004

The steadily increasing utilization of bio‐waste compost in German viticulture requires a more detailed investigation of nitrogen (N) mineralization parameters for mature bio‐waste compost applied to vineyard soils. N mineralization kinetics were described with two superposing exponential equations. Long‐term aerobic laboratory incubation experiments of 12 soil‐compost substrates revealed that 5±2.8% of its total N content could be released from a rapidly decomposable fraction (half‐life period t50 = 41 d at 15°C) and another 60±2.9% from a slower decomposable fraction (t50 = 490 d). The remaining proportion (35%) is considered not to be released in the medium term. The obtained potentially mineralizable nitrogen of 65% of total compost N significantly differs from current fertilizer recommendations, which were adopted from calculations for agricultural conditions. For fertilizer recommendations in viticulture, we recommend the consideration of a higher N‐mineralization potential for organic fertilizers.
The influence of phosphorus nutrition on the physiological response of moth bean genotypes to drought
Authors: Garg Balvinder K. , Burman Uday , Kathju Shyam
Published: August 2004

Four genotypes of moth bean (Vigna aconitifolia Jacq. Marechal), including two early (RMO‐257 and CZM‐18) and two late flowering types (CAZRI moth‐1 and Jawala) were grown at two levels of phosphorus (0 and 40 kg ha–1) and subjected to drought by withholding of water until wilting at the pre‐flowering stage in a pot trial. Drought significantly decreased plant water potential, relative water content, rate of net photosynthesis, contents of chlorophyll, starch, soluble protein, and nitrate reductase activity in all genotypes. The adverse effects of drought were less pronounced in early than in late flowering genotypes. Phosphorus application significantly ameliorated the negative effects of drought on above parameters, particularly in the late genotypes. We conclude that P addition to moth bean may be justified even in low‐rainfall years because of its ability to improve yield under water‐limited conditions.
Compositional nutrient diagnosis and main nutrient interactions in yellow pepper grown on desert calcareous soils
Authors: García‐Hernández José Luis , David Valdez‐Cepeda Ricardo , Murillo‐Amador Bernardo , Nieto‐Garibay Alejandra , Beltrán‐Morales Luis Felipe , Magallanes‐Quintanar Rafael , Troyo‐Diéguez Enrique
Published: August 2004

Mineral‐nutrient stress is one of the main factors limiting crop production, especially in arid lands. The mineral requirement of a crop is difficult to determine, and the interpretation of foliar chemistry composition is not easy. This study was conducted to compute the minimum yield target for fresh fruit of yellow pepper (Capsicum annuum L.) and the corresponding Compositional Nutrient Diagnosis (CND) as well as to identify significant nutrient interactions of this crop in desert calcareous soils. Preliminary CND norms were developed using a cumulative variance‐ratio function and the chi‐square distribution function. From a small database, we computed means and standard deviations of row‐centered log ratios, VX, of five nutrients (N, P, K, Ca, and Mg) and a filling value, R, which comprises all nutrients not chemically analyzed and quantified them in 54 foliar samples of the popular yellow pepper cv. ‘Santa Fé’. This cultivar is widely grown in northwest Mexico under arid conditions. These norms are associated to fresh fruit yields higher than 15.04 t ha–1. Principal‐component analyses, performed using estimated CND nutrient indexes, allowed us to identify four interactions: negative P‐Ca, P‐Mg, and N‐K, and positive Ca‐Mg. Pepper plants growing on calcareous soils tend to take up more Ca and Mg than considered as optimum in other soil conditions.
Effect of defoliation on patterns of carbon exudation from Agrostis capillaris
Authors: Murray Philip , Ostle Nicholas , Kenny Carolyn , Grant Helen
Published: August 2004

Grassland ecosystems are important global sinks and sources of atmospheric carbon (C). In this study, we used an in‐situ 13CO2 tracer approach to quantify differences in short‐term C exudation from defoliated and non‐defoliated Agrostis capillaris (L.) plants subjected to natural diurnal light and temperature regimes and rainfall events. Results showed: 1. There was no significant difference in overall carbon exudation from the plants as a result of defoliation; 2. defoliation significantly increased exudation of recent photosynthate (i.e., 13C labeled); 3. there was a distinct and statistically significant diurnal trend in C exudation with root C exudation increasing during the day and early evening and decreasing during the night and early morning. The importance of light/temperature and defoliation as drivers of patterns of root C exudation and the contribution of recent assimilate C to atmosphere‐plant‐soil carbon flow are discussed.
Development and practical test of a weighable groundwater lysimeter for floodplain sites
Authors: Bethge‐Steffens Doerthe , Meissner Ralph , Rupp Holger
Published: August 2004

Presently, the soil water balance of flood‐influenced soils in fluvial plains is insufficiently described. The new development of a weighable groundwater lysimeter is the basis for recording the water‐balance components precipitation, evapotranspiration, groundwater recharge, capillary rise, and interaction with the water course. Soil‐hydrologic measuring setups at two floodplain sites of the Elbe river serve for direct comparability of lysimeter measurements with data obtained on site. A groundwater control was designed for lysimeters that automatically adjusts the current groundwater level at the floodplain measuring setups and quantifies inflow into or outflow from the lysimeter. It turned out that the lysimeter developed is capable of identifying the individual water‐balance quantities at high accuracy. Contrary to previous assumptions, it was possible to prove groundwater recharge for the floodplain sites.
Ist der Konzentrationsfaktor k eines aggregierten Bodens als steuernde Größe der mechanischen Druckverteilung in Böden eine Konstante?
Authors: Becher Hans Heinrich
Published: August 2004

Die Mechanisierung in der Land‐ und Forstwirtschaft hat u. a. zu einer erheblichen Zunahme der Gewichte der im Gelände eingesetzten Maschinen und Geräte geführt. Letztere überschreiten zumindest in voll beladenem Zustand mit etwa 60 t (Zuckerrübenroder) deutlich das zulässige Gewicht von 40 t für Fahrzeuge im Straßenverkehr. Die durch diese oder ähnlich hohe Auflasten verursachte Bodenverdichtung steht im Widerspruch zu den Zielen des Bundesbodenschutzgesetzes. Deshalb ist die Beschäftigung mit der Druckfortpflanzung in tiefe Bodenschichten notwendig. Anhand einiger Beispiele wird gezeigt, dass der Konzentrationsfaktor k, der die Druckfortpflanzung steuert, sich unter dem Einfluss von Natur (Bodengenese, Wassergehalt) und/oder Menschen (Bodenbearbeitung, Ernte) sowohl räumlich als auch zeitlich ändert. Diese nicht vermeidbare Variabilität erschwert die Abschätzung der theoretischen Reichweite einer Bodenverdichtung anhand nur weniger Messwerte. Denn selbst während der Passage eines Gespanns ändern sich die Bedingungen für die Bodenverdichtung. Folglich ist der Konzentrationsfaktor k keine Bodenkonstante.
Experimental determination of climate‐change effects on above‐ground and below‐ground organic matter in alpine grasslands by translocation of soil cores
Authors: Egli Markus , Hitz Christian , Fitze Peter , Mirabella Aldo
Published: August 2004

We used the soil‐core translocation method to investigate the effect of increased temperature on above‐ and below‐ground phytomass and organic matter in cool alpine areas. The translocation of undisturbed soil cores from a high alpine site (2525 m a.s.l.) to an alpine site near the timberline (1895 m a.s.l.) achieved an effective artificial warming of 3.3 K. From a methodological point of view, the translocation of soil cores was performed successfully. Soil cores moved to a new site at the same altitude showed no change in above‐ and below‐ground vegetation, bulk density, and soil skeleton. At both sites, soils were Haplic Podzols with a similar chemistry and clay mineralogy. At the lower elevation site, however, podzolization processes seemed to be more pronounced. As a consequence, the translocation of the soil cores probably led to a disturbance of the actual steady state that had been established after about 10,000–13,000 years of soil formation. This might have affected the adaptability of the vegetation system. Therefore, it cannot be fully excluded that the experimental design influenced the results. Translocation of soil cores from a very cool to a warmer site led to a distinct decrease in above‐ground phytomass (about –45%) over the experimental period of two years. Below‐ground phytomass significantly decreased (up to –50%) in the topsoil (0–5 cm) after artificial warming. Possible mechanisms are that roots reduced photosynthesis and hence C flow below‐ground, a reduction of soil moisture that would have led to root death (not a very probable cause, however) or an abrupt change in the radiation duration and flux which affected root growth (also not very probable). Fast climate change exceeded the ability of the above‐ground and below‐ground phytomass to adapt quickly. Whether the decrease in phytomass was a short‐term or a long‐term response to climate warming remains uncertain. Based on a gradient study (climosequence at the same locality), we hypothesize that the decreased plant productivity might be a short‐term effect.
Temperature functions of the rate coefficients of net N mineralization in sandy arable soils. Part I. Derivation from laboratory incubations
Authors: Heumann Sabine , Böttcher Jürgen
Published: August 2004

This study aimed to experimentally determine adequate temperature functions for the rate coefficients of net N mineralization in sandy arable soils from NW Germany. Long‐term laboratory incubations were carried out in seven sandy arable soils at 3°C, 10°C, 19°C, 28°C, and 35°C in order to derive the rate coefficients of a simultaneous two‐pool first‐order kinetic equation. Thereby we differentiated between a small, fast mineralizable N pool, comprising mainly fresh residues, and a larger, slowly mineralizable N pool of old, humified organic matter. The rate coefficients were plotted against temperature, and fits of several different functions were tested: Arrhenius, Q10, and multiple non‐mechanistic equations. The two derived rate coefficients showed very different temperature functions. Especially in critical temperature ranges (<5/10°C, >30/35°C) common Q10 functions failed to fit well, and, only below 10°C, the Arrhenius functions were in agreement with mean measured rate coefficients. Over the studied temperature range, only relatively complex, multiple equations could adequately account for the observed patterns. In addition, temperature functions that have been derived earlier from loess soils from NW Germany were found not to be transferable to the sandy arable soils studied. Thus, the results strongly question the use of the same Arrhenius or Q10 function or the same rate modifying factor for different N pools as well as for different soils as is generally done in models. Evaluations with field measurements of net N mineralization in part II of the paper (Heumann and Böttcher, 2004) will show which functions perform best in the field.
Cation exchange properties of soils derived from lignite ashes
Authors: Zikeli Sabine , Kastler Michael , Jahn Reinhold
Published: August 2004

In Saxony‐Anhalt, Germany, an area of about 6000 ha is covered by lignite‐ash‐derived substrates. In some cases, pollutants like heavy metals or toxic organic compounds had been disposed of together with the lignite ashes. For this reason, we assessed factors influencing the cation exchange capacity (CEC) of lignite‐ash substrates exposed to natural weathering.

We chose four research sites reflecting the different methods of disposal: two dumped landfills and two lagooned ashes of different ages. After determining the CEC at pH 8.1 (CECpot), we evaluated the influence of the content of silt and clay and the content of total organic C. As lignite‐ash‐derived substrates are rich in oxalate‐extractable Si, Al, and Fe, we performed an oxalate extraction and determined afterwards the CECpot to assess the contribution of oxalate‐soluble compounds to the CECpot. Moreover, we determined the variable charge of selected samples at pH values ranging from 4 to 7.

The lignite‐ash‐derived soils had a high CECpot with means ranging from 25.1 cmolc kg–1 to 88.8 cmolc kg–1. The influence of the parent material was more important than the degree of weathering. The content of total organic C consisting of pedogenic organic matter and coked lignite particles together with the content of silt and clay played a statistically significant role in determining the CEC.

Another property that influenced the amount of CEC in medium textured lignite ashes was the content of oxalate‐soluble silica and aluminum. After oxalate extraction, they lost about 30% of their CEC due to the dissolution of oxalate‐soluble compounds. In coarse textured lignite ashes, oxalate extraction led to higher amounts of CEC, probably due to an increase of surface area resulting either from the disintegration of particles or from etching caused by insufficient dissolution of magnetite and maghemite. Moreover, lignite‐ash‐derived substrates exhibit a high amount of pH‐dependent charge. The CEC decreased by 40% in a topsoil sample and by 51% in a subsoil sample as the pH declined from 7 to 4.
Microbial biomass and respiration in soils derived from lignite ashes: a profile study
Authors: Machulla Galina , Zikeli Sabine , Kastler Michael , Jahn Reinhold
Published: August 2004

Microbial biomass C and soil respiration measurements were made in 17–20 yr old soils developed on sluiced and tipped coal‐combustion ashes. Topsoil (0–30 cm) and subsoil (30–100 cm) samples were collected from three soil profiles at two abandoned disposal sites located in the city area of Halle, Saxony‐Anhalt. Selected soil physical (bulk density and texture) and chemical (pH, organic C, total N, CEC, plant available K and P, and total Cd and Cu) properties were measured. pH values were significantly lower while organic C and total N contents and the C : N ratio were significantly higher in the topsoil than in the subsoil indicating the effects of substrate weathering and pedogenic C accumulation. Likewise, microbial biomass C, K2SO4‐extractable C, and soil respiration with median values of 786 μg biomass C g–1, 262 μg K2SO4‐C g–1, and 6.05 μg CO2‐C g–1 h–1, respectively, were significantly higher in the topsoil than in the subsoil. However, no significant difference was observed in metabolic quotient between the topsoil and the subsoil. Metabolic quotient with median values of 5.98 and 8.54 mg CO2‐C (g biomass C)–1 h–1 for the 0–30 cm and 30–100 cm depths, respectively, was higher than the data reported in the literature for arable and forest soils. Microbial biomass C correlated significantly with extractable C but no relationship was observed between it and total N, Cd, and Cu contents, as well as plant‐available K and P. We conclude that the presence of the remarkable concentration of extractable C in the weathered lignite ashes allowed the establishment of microbial populations with high biomass. The high metabolic quotients observed might be attributed to the heavy‐metal contamination and to the microbial communities specific to ash soils.
Adding dissolved organic carbon to simulate freeze‐thaw related N2O emissions from soil
Authors: Sehy Ulrike , Dyckmans Jens , Ruser Reiner , Munch Jean Charles
Published: August 2004

It has been assumed that high winter N2O emissions from soils are the result of increased amounts of microbially available organic C liberated during freezing and metabolized during subsequent thawing. In a laboratory experiment, we attempted to simulate freeze‐thaw events by adding dissolved organic C (DOC) to sieved soil of high water content (95% water‐filled pore space). In a full factorial design, CO2 and N2O emissions of a) soil samples provided with DOC extracted from frozen soil and b) soil samples frozen for 46 days and thawed were compared. Additionally, NO$_3^-$, DOC and microbial ATP contents of all treatments were repeatedly analyzed during the experiment.

The addition of DOC to unfrozen soil (–F+C) resulted in a substantial (22‐fold) increase in N2O emissions as compared to the control (–F–C). However, following thawing, the increase in N2O emissions was much larger (828‐fold in +F–C and 1243‐fold in +F+C). Freezing, but not the addition of DOC led to increased CO2 emissions. Neither treatment affected microbial adenylate content. By adding 15N‐labeled nitrate to the soil samples, the main process leading to elevated N2O flux rates after both DOC addition and freeze‐thaw treatment was identified as denitrification.

We conclude that the availability of C substrate plays an important role for freeze‐thaw‐related N2O emissions. However, the fact that the simulated treatment and the freeze‐thaw treatment yielded significantly different amounts of N2O suggests that both quantity and quality of available C differed between the treatments. The localization of the liberated substrate, i.e., the availability in situ, seems to be of major importance for the amount of N2O produced.
Capillary gas chromatography analysis of Ethiopian mustard to determine variability of fatty acid composition
Authors: Genet Tsige , Labuschagne Maryke T , Hugo Arno
Published: August 2004

Ethiopian mustard (Brassica carinata A. Braun) is an oil crop grown in Ethiopia. However, the oil is considered low quality, as it contains long chain monounsaturated fatty acids, mainly erucic acid. High erucic acid content is beneficial for the polymer industry, whereas low erucic acid is recommended for food purposes. Both linoleic and linolenic acids are essential fatty acids; however, less than 3% linolenic acid is preferred for oil stability. The objectives of this study were to determine fatty acid composition of Ethiopian mustard to determine the range of genetic diversity for these traits. The genotypes were analysed by capillary gas chromatography (CGC). Twenty‐six fatty acids were identified. In all accessions, the predominant fatty acids were erucic, linoleic, α‐linolenic and oleic, followed by gadoleic and palmitic. To a lesser extent stearic, vaccinic, nervonic and behenic acids were found in all accessions. Significant correlations were found between palmitic acid and stearic acid (positive), between erucic acid and palmitic, stearic, vaccinic, oleic, linoleic and α‐linolenic acids (negative) and eicosenoic acid (positive). Selection and hybridization techniques can be applied to modify the oil content of Ethiopian mustard, considering the variability observed. Copyright © 2004 Society of Chemical Industry