bluuebunny/crossref_metadata_2025 huggingface dataset:
The Hydrological Cycle in Atmospheric Reanalysis
Authors: Beljaars Anton , Andrae Ulf , Kallberg Per , Simmons Adrian , Uppala Sakari , Viterbo Pedro
Published: April 2006

Atmospheric (re‐)analysis is a powerful tool to create data sets that provide a good description of the atmosphere including the hydrological cycle. Atmospheric analysis systems use a numerical weather prediction model to propagate the state of the atmosphere in time. Observations, which are irregular in space and time, are inserted into the system in such a way that an optimal blend is obtained between the background fields (forecast from e.g. 6 hours before) and the observations. Observations range from traditional surface observations and radiosondes, to commercial aircraft observations, cloud track winds from satellites and profiling measurements from infrared and microwave instruments in space. Re‐analyses are performed to benefit from the most recent model improvements, data assimilation improvements and increased computer power and to obtain a time series that does not suffer from system changes as in operational numerical weather prediction. Current re‐analyses have a spatial resolution of the order of 1 degree with a temporal sampling interval of 3 to 6 hours. Re‐analysis products have the advantage of being projected on a global numerical grid and have no gaps.

The ECMWF 40‐year Re‐Analysis is described as an example. Its realism is discussed by comparing with observations of precipitation, vertically integrated water vapor, moisture convergence and surface fluxes over land and ocean. It is concluded that re‐analysis products are very useful to study the hydrological cycle in the atmosphere. The synoptic variability is particularly good although biases may exist in some of the parameters.
Integrated Land and Water Resources Management
Authors: Calder Ian R
Published: April 2006

The need for Integrated Land and Water Resources Management (ILWRM), to meet and balance competing demands for food, timber and water, for conservation, amenity, recreation and the environment and for supporting people's livelihoods, is discussed. The principles of ILWRM including notions of sustainability, approaches to the economic valuation of land and water and demand management, are outlined. Also discussed are the differing public and science perceptions of the impacts of land use change, the interactions between land use, climate change, and water resources and how ILWRM can be implemented with stakeholder involvement.
Land Use Impacts on Water Resources – Science, Social and Political Factors
Authors: Forsyth Tim
Published: April 2006

Public perceptions of land‐use impacts on water resources are important because they influence formal environmental policies and popular attitudes about land use. For example, upland agriculture and deforestation are commonly blamed for reducing rainfall levels and for causing lowland water shortages, and some governments have consequently passed logging bans or restrictions on upland agriculture. However, there is intense controversy concerning whether these public perceptions are supported by scientific evidence; whether these policies may actually address underlying problems; and how far hydrological science is itself influenced by social and political factors. This article draws upon debates in social science (rather than hydrological science alone) to discuss linkages between public perceptions and scientific explanations of hydrological change. As examples, the article discusses the cases of so‐called Himalayan environmental degradation; dryland desiccation in the Sahel; and debates concerning the impacts of deforestation and reforestation in watersheds. The article argues that hydrologists should not categorize public perceptions and formal science separately, but see both as mutually evolving. Dominant perceptions, or “narratives”, of hydrological change may occur from various coincidences of historical research and public concern, and reflect the viewpoints and experiences of only selected social groups. It is suggested that hydrologists can help overcome apparent conflicts between public perceptions and scientific explanations by increasing public participation in describing and framing complex environmental problems, and using this information to make existing narratives more diverse and flexible. There is also a need to understand the political and institutional factors that lead to the persistence of contested narratives within different national or organizational contexts.
Environmental Flows: Managing Hydrological Environments
Authors: Gippel Christopher J
Published: April 2006

Environmental flows refer to the facets of natural flow regimes that are required to sustain riparian and aquatic life in a healthy condition, plus provide for the needs of those human uses that rely on, and do not compromise, stream health values. Environmental flow assessments are required for regulated rivers, where the flow regime has been modified, or flow volumes significantly reduced. The methodological trend has been from narrow studies that catered for a single fish species at one critical life phase to a holistic approach that aims to restore natural river processes. Consideration has also been given to the specific issues of flood flows required for wetland inundation and channel formation, needs of groundwater‐dependent ecosystems, the needs of estuarine ecosystems, and flows required for recreational activities. Holistic methodologies are particularly appropriate in developing countries with strong livelihood dependencies on the goods and services provided by aquatic ecosystems. The number of studies worldwide that report environmental flow recommendations greatly outweighs the number of studies that report scientific evaluation of the results of implementation of these recommendations. However, where implemented environmental flow regimes have been monitored, the results have generally been positive.
Inter‐Institutional Links in Land and Water Management
Authors: Amezaga Jaime M
Published: April 2006

This article reviews the institutional aspects of Integrated Land and Water Resources Management. It explores the definition of what constitutes an institution in the land and water sector and presents several approaches to institutional analysis applicable in this context. It examines land and water interinstitutional linkages at several levels: international, national, river basin, and upstream/downstream. For each of these levels, theoretical approaches and examples are discussed. While institutional constraints such as cross‐sectoral coordination and the conflict between different land‐based administrative structures are still common, there are an increasing number of instruments applicable to this problem at all levels. Ensuring basic human needs and rights associated with water and land and establishing institutional systems to benefit disadvantaged people and improve livelihoods remain the greatest challenges to integrated management.
The Role of Water Vapor and Clouds in the Climate System
Authors: Stephens Grahame
Published: April 2006

The exchanges of water between the different water reservoirs on Earth establishes the so‐called hydrological cycle. The influence of this cycle on the energy budget of Earth is central to understanding and predicting climate change. In fact, those processes that characterize the smallest of the water reservoirs ‐ namely the atmospheric branch of the hydrological cycle ‐ play an especially critical role in regulating climate change through feedbacks processes. Two key feedback processes are described. The first deals with the feedback associated with the relation between water vapor, radiation and temperature and the second concerns feedbacks associated with clouds and radiation.
Role and Importance of Paleohydrology in the Study of Climate Change and Variability
Authors: Ekwurzel Brenda
Published: April 2006

Paleohydrology has advanced our understanding of climate by uncovering the variability of the prehistoric water cycle. Various proxy records provide insight into aspects of the hydrologic cycle that occurred before the instrumental record and allow for paleoclimate reconstructions locally or over large regions. For example, geomorphologic methods can quantify megafloods; coral or sediment core methods create paleodischarge records; rodent middens archive changes in precipitation volume and temperature; closed‐basin lake level fluctuations offer quantitative evidence of changes in water balance, and tree‐rings provide a high‐resolution archive of precipitation or drought. This article reviews representative examples from the field of paleohydrology and demonstrates the role each has played in enhancing our understanding of climate variability.
Changes in Regional Hydroclimatology and Water Resources on Seasonal to Interannual and Decade‐to‐Century Timescales
Authors: Meko David
Published: April 2006

Precipitation, runoff, snowpack, and other elements of the hydrologic cycle respond to climate change on many different timescales. Responses are typically regional rather than local and are linked to large‐scale features of the general circulation of the atmosphere. Changes in regional hydroclimatology are important to water resources in most parts of the world, but especially in arid and semiarid regions that are often plagued by chronic shortfalls of water. Instrumental records of precipitation and streamflow indicate that changes on decadal‐and‐longer timescales have been large enough to be of practical importance, and paleoclimatic records suggest that even larger changes have occurred over the past few centuries. Tree‐ring records are perhaps the most useful of the paleoclimatic resources for extracting hydroclimatic estimates with annual resolution. Paleolimnological data has also figured prominently in pointing out possible large changes in regional hydroclimatology prior to the start of the tree‐ring record. In North America, multiple types of proxy records suggest low‐frequency variance in runoff may have been amplified about 500 years ago, with associated multidecadal periods of drought and wetness.
A Guide to International Hydrologic Science Programs
Authors: Lawford R G , Eden S
Published: April 2006

Building on the successes of a few mature organizations dealing with the hydrological sciences and the International Hydrologic Decade of the 1960s, the number of water research and applications programs has grown rapidly in the past two decades. This growth can be attributed to new global research priorities (e.g. climate change), new technologies (e.g. satellites and high speed computers), new environmental awareness (e.g. globalization and its environmental impacts), and a growing awareness of the limits to available safe water in many parts of the world. Although some progress was made towards better structuring of hydrologic research activities during preparations for the International Water Decade (1981–1990), the relative roles and relationships among the plethora of groups and projects can still be confusing unless the range of activities and responsibilities is viewed in a broader context. This overview provides some context for these programs.

In general, international hydrologic research activities are undertaken within a programmatic framework developed by a community of scientists and coordinated by international scientific organizations and government agencies. Because international frameworks and programs do not fund research directly, they must rely on nations for funding support and experts. Frequently, national and international programs are implemented in an iterative and symbiotic way whereby national programs provide a core set of projects, while international programs provide the intellectual frameworks and organizational structures. Effective implementation of international hydrologic science programs in this context relies on mutual trust and respect, and on the clear articulation and pursuit of a shared vision.

This article provides an overview of the international hydrological science programs and their priorities, and identifies related global hydrometeorological and applications programs that either directly or indirectly provide scientific support for water management. It also describes mechanisms that facilitate the application of hydrologic science to regional and national water resource issues and those that inform the public and decision makers of the results from these international science programs.
Hypercapnia
Authors: Dahan Albert , Olofsen Erik
Published: April 2006

Hypercapnia or the increase in arterial carbon dioxide tension (PaCO
2
) above normal values (4–6.5 kPa, 30–48 Torr) is often observed in patients with pulmonary disease, patients with a drug‐induced reduction of the ventilatory drive (for example, because of administration of opioid‐like drugs or anesthetics), or is artificially induced to study the ventilatory control system (for example, by increasing inspired CO
2
to study the effects of drugs on this control system). In this short review, we will focus on the latter, i.e., the mathematical description of the ventilatory controller and some techniques to measure the ventilatory drive. Note that the model(s) we will discuss can be applied to “chemical control of breathing” only. Chemical control of breathing is control dependent on arterial blood gasses (e.g., PaCO
2
, PaO
2
, and pH), and it is active during states of mental relaxation, such as non‐REM sleep, anesthesia, and possibly physical relaxation. The models do not apply to the respiratory effects of exercise or behavioral/emotional activities such as eating, speaking, and playing a musical instrument.
Hypoxia
Authors: Ward Denham S. , Jensen Jens Ingemann
Published: April 2006

A great many cellular and physiological effects of hypoxia exist and a great difference exists in the hypoxic tolerance among species. For example, both the crucian carp (related to the goldfish) and some freshwater turtles can tolerate anoxia for extended periods of time, and they have evolved different mechanisms for this tolerance. Getting oxygen from the environment into the cells requires multiple coordinated steps of both diffusion and convection. The step of getting oxygen into the blood is, in many ways, quantitatively the most important. This chapter will concentrate on the changes in pulmonary ventilation that result from hypoxic exposure, and the development of quantitative models to describe this response.
Image Coding
Authors: Gerek Ömer Nezih , Çetin A. Enis
Published: April 2006

Digital images constitute a significant portion of the digital data that are stored on disks and transferred on wired/mobile networks. A typical image occupies a large amount of memory in a database. For example, for a Web‐sized color image of size 640×480, the raw file size is about 1 MB. The file sizes of special purpose images, such as medical (CT, MRI, US, etc.) or landsat images, are even larger. In a communication system, this would mean bandwidth, and a large disk space for storage. In either case, image data compression or image coding is the remedy. In this article, we will describe basic issues of image coding and indicate some novel techniques that are currently used.
Microfluidics
Authors: Cunningham David
Published: April 2006

This chapter reviews the area of microfluidics from a broad perspective with the aim of describing the current workings, state of the technology, and application to commercial products. An historical perspective places current technologies into perspective. Manufacturing and construction techniques are described for some of the most common processes. Key aspects of capillary electrophoresis are covered to give a basic understanding of electroosmotic flow and electromigration, necessary to understand the workings of commercially available chips. Various methods and applications are described for the generation of discrete small volumes and the movement of small volumes. Finally, microfluidic components are described with examples of commercial products.
Skin
Authors: Kudsi Omar Yusef , Pomahac Bohdan
Published: April 2006

Skin plays a crucial role in the interaction with the surrounding atmosphere and covers the external body. Skin loss remains one of the most evident problems in the treatment of various clinical cases including burned patients, diabetic foot ulcers, venous leg ulcers, and wounds. Loss of large skin areas is incompatible with sustained life. With the recent advancement of skin engineering, scientists currently seek a universal skin product. They aim to achieve unlimited production of anti‐rejection skin. Skin substitute materials may be able to stimulate regeneration rather than repair, and tissue‐engineered skin may match the quality of split‐skin autografts, the present gold standard. Although scientific and technological advances have contributed to the development of skin substitutes, continued research has the potential to dramatically alter the field of medicine. Improvement of skin alternatives will result from inclusion of additional cell types and from modifications of culture media and scaffolds. The introduction of specific design modifications to tissue‐engineered skin is important because the addition of such features will expand the use of skin products beyond those of healing wounds. For example, tissue‐engineered skin could be used to treat a variety of diseases by delivering growth factors or other therapeutic agents. Successful steps in this field have already been taken; it is possible to transfect keratinocytes with adenoviruses or retroviruses that can carry genes of interest.
Space Physiology
Authors: Beckers Frank , Verheyden Bart , Aubert André E.
Published: April 2006

Space exploration has been a dream of humankind ever since Baron von Münchausen, Jules Verne, Tsiolkovsky, Goddard, and many others. However, this intriguing environment is not without risks. The human body has developed over the past thousands of years in the constant presence of gravity. When this gravitational force is no longer acting on the body, changes occur. Some of these changes occur immediately; others progress only slowly.

In the past 40 years of human space flight (first orbital flight by Yuri Gagarin in April 1961), several hazards for the human body have been identified. Bone mineral density is lost, and muscle atrophy and cardiovascular deconditioning occur. These changes in human physiology have to be reversed again when astronauts return to Earth. This reversal can cause adaptation problems, especially after long‐duration space flights. Also the reaction of the human physiology to radiation in space poses a huge risk at this moment.

To make long‐duration space flight possible, we must understand the mechanisms of physiological adaptation. Only with this knowledge can effective countermeasures be developed.
Tissue Engineering of Kidney, Bladder, and Urethra
Authors: Atala Anthony
Published: April 2006

Patients suffering from a variety of urologic diseases may be treated with transplanted tissues and organs. However, a shortage of donor tissues and organs exists which is worsening yearly because of the aging population. Scientists in the field of regenerative medicine and tissue engineering are applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured urologic tissues. The chapter reviews recent advances that have occurred in the regeneration of urologic organs and describes how these applications may offer novel therapies for patients with urologic disease.
Genotype–epigenotype–phenotype correlations in females with frontometaphyseal dysplasia
Authors: Zenker Martin , Nährlich Lutz , Sticht Heinrich , Reis André , Horn Denise
Published: April 2006

Frontometaphyseal dysplasia (FMD) belongs to a group of overlapping skeletal dysplasias, the common molecular basis of which are mutations of FLNA, the gene encoding filamin A. The nature of the mutation has been considered the major determinant of the phenotype within this group that comprises the otopalatodigital syndromes (OPD1, OPD2) and Melnick–Needles syndrome besides FMD. However, to date the molecular pathomechanisms are not well understood. In FMD only few FLNA mutations have been reported which do not cluster in a specific region of the protein. We report on a novel de novo mutation 5182G → T in exon 31 of the FLNA gene in a girl with manifestations of FMD and OPD1. This mutation is predicted to lead to the exchange of a highly conserved glycine residue at position 1,728 by cysteine (G1728C) in repeat 15 of the filamin A rod domain. In a second family with FMD, we identified a known mutation (S1186L) in a mother and her son. In contrast to most previous reports on manifesting females or carriers of the FLNA‐related skeletal dysplasias, the affected females presented here showed only mild to moderate skewing of X‐inactivation against the mutant allele. Our data may indicate that in females, genotype–phenotype correlation between certain FLNA mutations and OPD1 and FMD, respectively, is less strict than previously assumed. We propose that X‐inactivation is an important epigenetic modifier of the phenotype in females with the FLNA‐related skeletal dysplasias. © 2006 Wiley‐Liss, Inc.
Multicolor banding detects a complex three chromosome, seven breakpoint unbalanced rearrangement in an ICSI‐derived fetus with multiple abnormalities
Authors: Seller Mary J. , Bint Susan , Kavalier Fred , Brown Richard N. , Ogilvie Caroline Mackie
Published: April 2006

We describe a fetus from an intracytoplasmic sperm injection (ICSI) pregnancy with severe facial clefts, receding jaw, preauricular skin tags, postaxial hexadactyly, bi‐lobed right lung, supernumerary cranial bone, and dilated lateral ventricles of the brain. Using a combination of G‐banding, fluorescence in situ hybridization (FISH), whole chromosome paints (WCPs), subtelomere probes, and multicolor banding (MCB), the karyotype was found to include a de novo unbalanced highly complex chromosome rearrangement (hCCR) involving chromosomes 3, 12, and 15 with seven breakpoints, and including monosomy for two separate regions of chromosome 12. © 2006 Wiley‐Liss, Inc.
Folate gene polymorphisms and the risk of Down syndrome pregnancies in young Italian women
Authors: Coppedè Fabio , Marini Giulia , Bargagna Stefania , Stuppia Liborio , Minichilli Fabrizio , Fontana Ilaria , Colognato Renato , Astrea Guia , Palka Giandomenico , Migliore Lucia
Published: April 2006

Maternal impairments in folate metabolism and elevated homocysteinemia are known risk factors for having a child with Down syndrome (DS) at a young age. The 80G>A polymorphism of the reduced folate carrier gene (RFC‐1) has been recently demonstrated to affect plasma folate and homocysteine levels, alone or in combination with the 677C>T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene. We performed the present study on 80 Italian mothers of DS individuals, aged less than 35 at conception, and 111 Italian control mothers, to study the role of the RFC‐1 80G>A, MTHFR 677C>T, and MTHFR 1298A>C genotypes to the risk of a DS offspring at a young maternal age. When polymorphisms were considered alone, both allele and genotype frequencies did not significantly differ between DS mothers and control mothers. However, the combined MTHFR677TT/RFC‐1 80GG genotype was borderline associated with an increased risk (OR 6 (CI 95%: 1.0–35.9), P = 0.05), and to be MTHF1298AA/RFC‐1 80(GA or AA) was inversely associated with the risk (OR 0.36 (CI 95%: 0.14–0.96), P = 0.04). Present results seem to indicate that none of the RFC‐1 80G>A, MTHFR 677C>T, and MTHFR 1298A>C polymorphisms is an independent risk factor for a DS offspring at a young maternal age; however, a role for the combined MTHFR/RFC‐1 genotypes in the risk of DS pregnancies among young Italian women cannot be excluded. © 2006 Wiley‐Liss, Inc.
Interpretation of metabolic flux maps by limitation potentials and constrained limitation sensitivities
Authors: Wahl S. Aljoscha , Takors Ralf , Wiechert Wolfgang
Published: April 2006

Two new concepts, “Limitation Potential” and “Constraint Limitation Sensitivity” are introduced that use definitions derived from metabolic flux analysis (MFA) and metabolic network analysis (MNA). They are applied to interpret a measured flux distribution in the context of all possible flux distributions and thus combine MFA with MNA. The proposed measures are used to quantify and compare the influence of intracellular fluxes on the production yield. The methods are purely based on the stoichiometry of the network and constraints that are given from irreversible fluxes. In contrast to metabolic control analysis (MCA), within this approach no information about the kinetic mechanisms are needed. A limitation potential (LP) is defined as the reduction of the reachable (theoretical) maximum by a measured flux. Measured fluxes that strongly narrow the reachable maximum are assumed to be limiting as the network has no ability to counterbalance the restriction due to the observed flux. In a second step, the sensitivity of the reduced maximum is regarded. This measure provides information about the necessitated changes to reach higher yields. The methods are applied to interpret the capabilities of a network based on measured fluxes for a L‐phenylalanine producer. The strain was examined by a series of experiments and three flux maps of the production phase are analyzed. It can be shown that the reachable yield is drastically reduced by the measured efflux into the TCA cycle, while the oxidative pentose‐phosphate pathway only plays a secondary role on the reachable maximum. © 2006 Wiley Periodicals, Inc.
Production of target‐specific recombinant human polyclonal antibodies in mammalian cells
Authors: Wiberg Finn C. , Rasmussen Søren K. , Frandsen Torben P. , Rasmussen Lone K. , Tengbjerg Kaja , Coljee Vincent W. , Sharon Jacqueline , Yang Chiou‐Ying , Bregenholt Søren , Nielsen Lars S. , Haurum John S. , Tolstrup Anne B.
Published: April 2006

We describe the expression and consistent production of a first target‐specific recombinant human polyclonal antibody. An anti‐Rhesus D recombinant polyclonal antibody, Sym001, comprised of 25 unique human IgG1 antibodies, was produced by the novel Sympress expression technology. This strategy is based on site‐specific integration of antibody genes in CHO cells, using the FRT/Flp‐In recombinase system. This allows integration of the expression construct at the same genomic site in the host cells, thereby reducing genomic position effects. Different bioreactor batches of Sym001 displayed highly consistent manufacturing yield, antibody composition, binding potency, and functional activity. The results demonstrate that diverse recombinant human polyclonal antibody compositions can be reproducibly generated under conditions directly applicable to industrial manufacturing settings and present a first recombinant polyclonal antibody which could be used for treatment of hemolytic disease of the newborn and/or idiopathic thrombocytopenic purpura. © 2006 Wiley Periodicals, Inc.
Oxidative Rearrangements of Tricyclic Vinylcyclobutane Derivatives
Authors: Grota Juliane , Mattay Jochen , Piech Krzysztof , Bally Thomas
Published: April 2006

Three tricyclic vinylcyclobutanes (3‐methylenetricyclo[5.3.0.02,6]decanes 1–3) have been subjected to ionization by photoinduced electron transfer in solution and by X‐irradiation in Ar matrices. All three compounds undergo oxidative cycloreversion; the cleavage of the four‐membered ring, however, occurs in a different direction depending on the presence of a methyl group in position 6 of the tricyclic framework. In those derivatives, cycloreversion is found to lead to 1‐methyl‐8‐methylene‐1,6‐cyclodecadiene radical cations (5.+ from 1, 8.+ from 2) which upon back electron transfer yield two different hydrocarbons (6 from 5.+, 9 from 8.+), depending on the configuration around the endocyclic double bonds of the respective cyclodecadiene derivative. In the absence of a methyl group on C6, the cycloreversion leads to a radical cation complex between 1‐methylenecyclopent‐2‐ene and cyclopentene (12.+) which appears to revert to 3 on back electron transfer. The intermediate radical cations 5.+, 8.+, and 12.+ have been identified and characterized by UV/Vis and IR spectra in Ar matrices. The mechanism of their formation is elucidated by quantum chemical calculations.
Understanding Sulfone Behavior in Palladium‐Catalyzed Domino Reactions with Aryl Iodides
Authors: Alonso Inés , Alcamí Manuel , Mauleón Pablo , Carretero Juan C.
Published: April 2006

Unlike traditionally used acyclic 1,2‐disubstituted alkenes, the reaction of α,β‐unsaturated phenyl sulfones with aryl iodides under Heck reaction conditions takes place mainly by means of a four‐component domino process, involving one unit of the alkene and three units of the aryl iodide, affording substituted 9‐phenylsulfonyl‐9,10‐dihydrophenanthrenes. We report here the results of a computational study on the mechanism of this domino arylation reaction. Based on these results we can explain why vinyl sulfones, unlike other electron‐deficient alkenes such as enones, preferentially follow this domino pathway instead of the usual Heck pathway. The key step is a CH activation process in which a five‐membered palladacycle is formed. The greater ability of vinyl sulfones, relative to enones, to reach the transition state that leads to the formation of the initial palladacycle makes the difference.
Density Functional Theory Study on Electronic Property of Cluster NixFe and NiFex (x=1–5)
Authors: Fang Zhi‐Gang , Hu Hong‐Zhi , Guo Jing‐Xue
Published: April 2006

More than one hundred models were designed to reflect the local structure and electronic property of Ni‐Fe amorphous alloys. After calculating by DFT method, a series of configurations of clusters NixFe and NiFex (x=1–5) were gained. The configurations, which possessed the lowest energies and non‐imaginary frequencies, were considered the most stable optimized structures. The catalytic activity, charge and magnetic properties were analyzed and discussed. The different Fe content changed the catalytic properties of clusters through altering the value of Fermi level of every cluster. However the density of state (DOS) nearby Fermi level and average 3d orbital population of atom Ni, which were also important properties related to the catalytic activation, were little changed. Based on the Fermi level, the activity of catalyst toward hydrogenation reaction would be considered best when the ratio of Ni to Fe was close to 1. The Fermi level of clusters was far distant to the level of nitrogen in singlet state. It would be the reason why the reaction condition in ammonia synthesis and nitrogen fixation process was rigorous. When Fe atom contents were higher than 75% (NiFe3), the electrons transferred from atom Fe to Ni, but when the ratio was decreased, the transfer was reversed. The ratio of atoms of local structure also played an important role in the aspect of electron transition. On the average 3d orbital population of atom Fe, the average magnetic moments of Fe atoms in clusters were calculated. When Fe atom contents were 50% nearly, the average magnetic moment achieved the highest point.
Simulative Calculation of Mechanical Property, Binding Energy and Detonation Property of TATB/Fluorine‐polymer PBX
Authors: Ma Xiu‐Fang , Xiao Ji‐Jun , Huang Hui , Ju Xue‐Hai , Li Jin‐Shan , Xiao He‐Ming
Published: April 2006

Molecular dynamics (MD) method was used to simulate 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) coated with fluorine containing polymers. The mechanical properties and binding energies of PBXs were obtained. It was found that when the number of chain monomers of fluorine containing polymers was the same, the elasticity of TATB/F2314 was increased more greatly than others and the binding energy of TATB/F2311 was the largest among four PBXs. Detonation heat and velocity of such four PBXs were calculated according to theoretical and empirical formulas. The results show that the order of detonation heat is TATB>TATB/PVDF>TATB/F2311>TATB/F2314>TATB/PCTFE while the order of detonation velocity is TATB/PVDF<TATB/F2311<TATB/F2314<TATB/PCTFE<TATB.
Synthesis and Herbicidal Activity of 2‐Cyano‐3‐methylthio‐3‐substituted Methylaminoacrylates
Authors: Gao Ying , Zou Xiao‐Mao , Yu Li‐Min , Xu Han , Liu Bin , Zhu You‐Quan , Hu Fang‐Zhong , Yang Hua‐Zheng
Published: April 2006

A series of 2‐cyano‐3‐methylthio‐3‐substituted methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem II (PSII) electron transport, in order to estimate the effect of fluorine atom, pyridyl group, chirality and ester chain on activity. The important intermediate 2‐fluoro‐5‐aminomethylpyridine was synthesized with high yield. The bioassay results showed that most of title compounds had high herbicidal activity in postemergence treatment. The introduction of an α‐methyl into the 3‐substituted methylamino could improve the activity notably. The replacement of hydrogen by chlorine or fluorine group and phenyl by pyridyl group showed different effects, and at the same time, the ester chain affected the activity too.
Ferrocene Derivative Mediator Bonded Sol‐gel Membrane Glucose Biosensor
Authors: Xuan Guang‐Shan , Kim Moon‐Chang , Her Dae‐Sung , Lee Heung‐Lark
Published: April 2006

The sol‐gel derived glucose biosensor was developed, and the sol‐gel membrane was organically modified by N‐(3‐triethoxysilylpropyl)‐ferrocenylmethylamine (FcSi) as sol‐gel precursor to make electrochemical biosensor. The structure of biosensor was sol‐gel/FcSi+GOx/GC type (glucose oxidase, GOx). The ferrocene mediator was chemically immobilized to the silane network, and GOx was entrapped to the sol‐gel glass network. Therefore, these structures prevented mediator leakage and retained the enzyme activity. Additionally, pH of electrolyte, temperature effects, and interference of positive substances with biosensor were investigated. And the electrochemical performance of biosensor was studied by amperometry. The results indicated that the linear range, detection limit, and response slope of biosensor was 2.00×10−4–1.57×10−3 mol·L−1, 2.0×10−4 mol·L−1 and 5.06×105 nA·mol−1·L, respectively.
Determination of Trace Amounts of Vanadium by Kinetic‐Catalytic Spectrophotometric Methods
Authors: Pouretedal H. R. , Keshavarz M. H.
Published: April 2006

Kinetic‐catalytic spectrophotometric methods were proposed for the determination of trace amounts of vanadium element as vanadium(IV) and/or V(V) ions. The vanadium(IV) as VO2+ ion and/or vanadium(V) as VO3− ion showed a catalytic effect on the kinetic reactions between a color reagent such as methylthymol blue (MTB) or SPADNS and bromate in acidic media. The rate of decrease in the absorbance of the reagent MTB at 440 nm or SPADNS at 510 nm was proportional to concentration of V(IV) and/or V(V) ions in the solution. The linear ranges for determination of vanadium were obtained in the range of 1.0–150 and 5.0–100.0 µg/L by the fixed‐time and slope methods, respectively, with using MTB as reagent. In the presence of SPADNS as reagent, the calibration curves were made in the amplitude 1.0–200.0 and 5.0–150 µg/L of vanadium ion by the fixed‐time and slope methods, respectively. Using fixed‐time method, the limits of detection were obtained to be 0.5 and 0.7 µg/L of vanadium in the presence of MTB and SPADNS as reagents, respectively. Detection limits of vanadium by slope method and reagents of SPADNS and MTB were obtained to be 3.5 and 3.8 µg/L of vanadium, respectively. The proposed methods were applied successfully to determination of vanadium in synthetic and real samples.
New Triterpene Saponins and Flavonol Glycosides from the Leaves of Ilex cornuta
Authors: Li Yan , Wu Tao , Chen Zhi‐Hong , Wang Zheng‐Tao
Published: April 2006

A new triterpene glycoside, pomolic acid 3‐O‐6"‐methyl‐β‐D‐glucuronopyranosyl‐(1→3)‐α‐L‐arabino‐pyranoside, and a new flavonol glycoside, quercetin 3‐O‐β‐D‐glucopyranosyl‐(1→2)‐α‐L‐arabinopyranoside together with three known triterpene saponins and two flavonol glycosides, were isolated from the leaves of Ilex cornuta. Their structures were established on the basis of spectroscopic analysis.
Impact of changes to the American Joint Committee on Cancer T classification on outcome prediction in patients with oropharyngeal cancer
Authors: Asper Joshua A. , Morrison William H. , Rosenthal David I. , Ahamad Anesa , Ang K. Kian , Garden Adam S.
Published: April 2006

BACKGROUND

The efficacy of the current 6th edition of the American Joint Committee on Cancer (AJCC) tumor staging criteria in improving outcome prediction for patients with oropharyngeal cancer was analyzed.

METHODS

From the database of the Department of Radiation Oncology at the University of Texas M. D. Anderson Cancer Center the authors identified 875 patients irradiated at the study institution for oropharyngeal cancer between January 1975 and December 1998. The tumors were restaged based on the 6th edition of AJCC tumor staging criteria to reassess the original outcome predictions, specifically overall survival (OS) and local control (LC).

RESULTS

Applying the new 6th edition staging system resulted in the following T classification distributions: T2, 301 tumors (34%); T3, 248 tumors (28%); T4a, 224 tumors (26%), and T4b, 102 tumors (12%). The 5‐year and 10‐year OS rates based on the new system were: T2, 65% and 45%; T3, 44% and 28%; T4a, 30% and 23%; and T4b, 26% and 12%, respectively. The 5‐year and 10‐year actuarial local LC rates based on the new system were: T2, 85% and 83%; T3, 73% and 71%; T4a, 61% and 58%; and T4b, 42% and 42%, respectively. Differences in OS and LC rates stratified by stage were found to be statistically significant both for the overall distribution of survival and pairwise comparisons of the 4 tumor stage groups.

CONCLUSIONS

The modifications established in the 6th edition of the AJCC tumor staging system for oropharyngeal tumors appear to be useful to distinguish prognostic groups for both LC and OS based on tumor stage. Cancer 2006. © 2006 American Cancer Society.
Supramolecular Assemblies with Honeycomb Structures by π‐π Stacking of Octahedral Metal Complexes of 1,12‐Diazaperylene (Eur. J. Inorg. Chem. 8/2006)
Authors: Kammer Stefan , Müller Holger , Grunwald Nicolas , Bellin Anja , Kelling Alexandra , Schilde Uwe , Mickler Wulfhard , Dosche Carsten , Holdt Hans‐Jürgen
Published: April 2006

The cover picture shows the honeycomb structure formed by π‐π stacking of homoleptic octahedral NiII complexes of the “large‐surface” ligand 1,12‐diazaperylene (dap), [Ni(dap)3](BF4)2 (Ni red, N green, C dark yellow, B blue, F light yellow). The [Ni(dap)3]2+ cation and one of the BF4− counterions form parallel nanosized channels (ca. 9.60 A° in diameter), which run along the crystallographic c axis and are filled with the other disordered BF4− counterion (omitted for clarity). The C3 symmetry of [Ni(dap)3]2+ is a prerequisite for forming the highly symmetrical supramolecular assembly. Details are discussed in the article by H.‐J. Holdt et al. on p. 1547 ff.
Land degradation assessment with the aid of geo‐information techniques
Authors: Jabbar Mushtak T. , Chen Xiaoling
Published: April 2006

This research integrated selected land degradation indicators (vegetation cover, proportion of drifting sand area, desertification rate, and population pressure) with geo‐information techniques (remote sensing, geographic information system and global positioning system) to assess the severity of land degradation risk. The northern part of Shaanxi province in China was taken as a case study. A computerized land degradation severity assessment was implemented, and ERmapper ver.6.2 and ARC/INFO GIS ver.8.3 environments were used to manage and manipulate thematic data, and to process satellite images and tabular data. Two Landsat TM images in October 1987 and October 1999 were used to produce land use/cover maps of the study area based on the maximum likelihood classification method. These maps were then used to generate land use, land cover change, vegetation degradation and land degradation maps for the study area during the study period, and their corresponding data were integrated into a systematic analysis. Results showed that the overall severity of land degradation in the study area worsened during the study period from 1987 to 1999 with severely, highly and moderately degraded land accounting for 73·8 per cent of the total area. While the area affected by desertification has increased, the rate of desertification has also accelerated to reach 41·5 km2 a−1. Risk of land degradation in the study area has increased, on average, by 39·4 per cent since 1987. Incorporation of both natural and anthropogenic factors in the analysis provided realistic assessment of the risk of desertification. The study area, in general, is exposed to a high risk of land degradation. Copyright © 2006 John Wiley & Sons, Ltd.
Mapping erosion risk and selecting sites for simple erosion control measures after a forest fire in Mediterranean France
Authors: Fox D. , Berolo W. , Carrega P. , Darboux F.
Published: April 2006

Major forest fires occur periodically in the Mediterranean environment. The impact of forest fires on soil erosion and runoff processes has been studied extensively, and it has been demonstrated that the first months after a fire represent a high risk period. Erosion control strategies must be established in the weeks following a forest fire to reduce fire impacts during the critical phase. Both dead and live vegetation techniques can be used to either reduce soil loss from slopes or trap sediments in streams before they enter the main channel: these include log erosion barriers, log debris dams and grass filter strips. The major challenge is defining where to position the measures quickly in a catchment where several thousand hectares have been burned. The method proposed here is based, firstly, on a simple soil erosion model that identifies critical erosion zones, and secondly, on a more detailed analysis of high risk slopes according to their potential impact on the main river channel, the value of the soil resource to be protected, the availability of pine logs, and accessibility to the site. Measurements of suspended sediment load in the main channel and tributaries confirmed that the erosion risk map was suitable for the purposes of the study. Many of the recommendations suggested were implemented and a study is underway to evaluate their effectiveness in reducing erosion and trapping sediments. Copyright © 2006 John Wiley & Sons, Ltd.
Curtailing water erosion of cultivated land: an example from north Norfolk, eastern England
Authors: Evans Robert
Published: April 2006

Much information has been gathered together from maps, air photos and field visits with regard to a parcel of land in north Norfolk, eastern England. Since the 1930s the field pattern, cropping and the incidence of water erosion have changed markedly. Ten fields were amalgamated into one by the late 1960s, there was a shift to winter cereals, and agricultural practices intensified leading to extensive and severe erosion. In 1982 a new owner decided to combat erosion and over time divided the one large 61‐ha field into four, and planted trees and hedges. This not only reduced the extent of erosion and connectivity of flow but also greatly increased the biodiversity of the landscape. There are few examples in the literature of farmer‐devised schemes to curtail erosion. Such schemes, if successful, can help alleviate runoff, erosion and sediment delivery to water courses. They can also be used to demonstrate to other farmers and policy makers which schemes work. Once a farmer accepts there is an erosion problem (s)he is capable of devising schemes which work without calling on the services of experts. Copyright © 2006 John Wiley & Sons, Ltd.
Composition of the volatile oils of Satureja spicigera C. Koch Boiss. and S. macrantha C. A. Mey from Iran
Authors: Gohari Ahmad Reza , Hadjiakhoondi Abbas , Sadat‐Ebrahimi Esmaeil , Saeidnia Soodabeh , Shafiee Abbas
Published: April 2006

The essential oils of the aerial parts of Satureja spicigera (C. Koch) Boiss. and S. macrantha C. A. Mey., from Iran, have been analysed by GC and GC–MS. Forty‐three compounds in the oil of S. spicigera, representing 97.4% of the total oil, and 48 compounds in the oil of S. macrantha, representing 92.1%, were identified. The oil of S. spicigera was rich in monoterpenes (89.9%) with thymol (37.3%) as the major compound, but the oil of S. macrantha consists of approximately equal amounts of monoterpenes and sesquiterpenes (34.2% and 30.8%, respectively) with spathulenol (14.0%) as the main component. Copyright © 2006 John Wiley & Sons, Ltd.
Essential oil composition of Sideritis hirsuta L. from Guadalajara Province, Spain
Authors: Palá‐Paúl Jesús , Pérez‐Alonso M. José , Velasco‐Negueruela Arturo , Ballesteros M. Teresa , Sanz Jesús
Published: April 2006

The essential oil from the aerial parts of Sideritis hirsuta L. gathered in Guadalajara Province, Spain, has been extracted by steam distillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC–MS). A total of 73 compounds have been identified, monoterpene compounds being the most important. The principal constituents have been identified as β‐phellandrene (23.8%), α‐phellandrene (9.2%), α‐pinene (8.2%) and (Z)‐β‐guaiene (8.1%). Although the chemical composition of the essential oil of this species from other provinces is similar, 44 of the 73 identified compounds have not been previously reported in this species. It is the first time that the sesquiterpene (Z)‐β‐guaiene (8.1%) has been detected and mentioned as a major constituent in this species, therefore it could be considered to describe a new chemotype for Sideritis hirsuta L. Copyright © 2006 John Wiley & Sons, Ltd.
Light‐induced controlled release of fragrance aldehydes from 1‐alkoxy‐9,10‐anthraquinones for applications in functional perfumery
Authors: Levrand Barbara , Herrmann Andreas
Published: April 2006

Light‐activated chemical delivery systems for the controlled release of fragrances have been shown to be effective in functional perfumery. Upon photolysis around 350 nm, 1‐alkoxy‐9,10‐anthraquinones release aldehydes or ketones and may thus be considered as promising precursors for the photochemical release of perfume molecules. A series of substituted and unsubstituted mono‐ and dialkoxy‐9,10‐anthraquinones was prepared by reaction of the corresponding fragrance bromides with commercial mono‐ or dihydroxy‐9,10‐anthraquinones. Photoirradiation of these compounds in polar and apolar solution yielded the desired fragrance aldehydes. Preliminary olfactory panel evaluations on fabric after exposure to ambient indoor daylight for several days indicated a slightly stronger odour in the presence of the fragrance precursors, as compared to a reference sample containing the unmodified perfumery raw material. Copyright © 2006 John Wiley & Sons, Ltd.