bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution and Ecology of Plant Mating Systems
Authors: Pannell John R 
Published: March 2010

AbstractThe mating system provides a description of the distribution of mating unions in a population; in hermaphrodites such as most flowering plants, this amounts to the rate of self‐fertilization versus outcrossing. Selfing has evolved numerous times in flowering plants, probably because selfers transmit an extra copy of their genes to their seed progeny, and because they can reproduce in the absence of mates. Nevertheless, selfed progeny tend to be less fit and selfing detracts from an individuals outcrossing potential. As a result, most plants avoid selfing via a number of molecular, morphological or phenological adaptations. The mating system also has important implications for the genetic structure of individuals and populations: individuals show reduced heterozygosity, reduced effective recombination and reduced effects of genetic conflict; and populations of selfers tend to be more genetically differentiated from one another than outcrossers.Key conceptsThe mating system describes and quantifies the distribution of mating unions in a population; in hermaphroditic plants, the mating system typically refers to the selfing or outcrossing rates.Self‐fertilization confers an automatic selective benefit, because selfed progeny carry two copies of a parent's genome rather than just one. An important possible cost of self‐fertilization is inbreeding depression, where selfed progeny have lower fitness than their outcrossed counterparts.Self‐fertilization can be costly because pollen used up in selfing is unavailable for competition to sire outcrossed progeny; this is known as pollen discounting.Self‐fertilization may be advantageous when mates or pollinators are scarce, because it provides reproductive assurance by allowing uniparental reproduction.Inbreeding depression can be caused by either overdominance, where heterozygotes have an advantage over both corresponding homozygotes, or partial dominance, where fitness is reduced on one homozygote by the expression of deleterious recessive alleles.Plants avoid self‐fertilization through molecular self‐incompatibility reactions, the spatial separation of the sexual functions within and among flowers (herkogamy or dicliny), or the temporal separation of the sexual functions (dichogamy).
Predicting Molecular Evolutionary Trajectories in Principle and in Practice
Authors: Weinreich Daniel M 
Published: March 2010

AbstractThe discrete, digital nature of DNA (deoxyribonucleic acid) defines a large but countable number of mutational trajectories between any two alleles. Even though some set of mutations jointly confer an improvement in an organism's reproductive success, it need not follow that all mutational trajectories to that allele are equivalent in the eyes of evolution by natural selection. To a good approximation, the key question is whether all mutations improve reproductive success in all combinations; if they do not, then some subset (even, possibly all) trajectories will be selectively inaccessible. Mutations that are only conditionally beneficial are said to exhibit sign epistasis, which several recent empirical studies demonstrate is pervasive. Biochemical and biophysical considerations of protein biology are beginning to shed light on the underlying mechanisms of sign epistasis and current theoretical attention is focused on its influence on selectively accessible trajectories in sexual population.Key concepts:Phenotypic change over evolutionary time must reflect underlying changes in genetic constitution of the population.Under reasonable assumptions, it is possible to enumerate all mutational trajectories a population might follow in the course of evolving from one genetic variant to another.Recent experimental work demonstrates that for several proteins, only a very small fraction of mutational trajectories are accessible to populations evolving under the action of natural selection.The identity of selectively accessible mutational trajectories reflects the underlying biochemistry and biophysics of the protein in question.
Genetic Factors Involved in Human Susceptibility to Infection by Schistosomiasis
Authors: Isnard Amandine , He Hongbin , Kouriba Bourema , Chevillard Christophe 
Published: March 2010

AbstractThree hundred million individuals are at risk of infection by schistosomes, which cause severe kidney and liver disease, and 280 000 deaths annually. Infection levels are mainly under the control of a major locus,SM1(Schistosoma mansoni 1), mapped in 5q31q33 region. An association between the rs1800925 polymorphism in theIL13promoter and infection levels was detected. Subjects bearing the rs1800925T/T genotype were much less infected than individuals with other genotypes. We went on to investigate whether other polymorphisms in genes involved in the TH2 cytokine immune response could affect susceptibility to schistosome infection. An association betweenSTAT6rs324013 polymorphism and infection levels was also found. These two polymorphisms which have an additive effect were not strongly correlated with any other tested markers surrounding the two genes. Moreover, these polymorphisms affect transcription factor binding to the promoter regions. These results are consistent with the TH2 cytokine pathway enhancing resistance to schistosome infection.Key concepts:IL13gene is associated to the control of infection levels in schistosomiasis.STAT6gene is associated to the control of infection levels in schistosomiasis.IL13andSTAT6polymorphisms have synergic effect.
Winogradsky, Sergei Nikolaevitch
Authors: Oren Aharon 
Published: March 2010

Abstract
Sergei Nikolaevitch Winogradsky (1856–1953), a Russian‐born microbiologist who worked in France for most of his life; his investigations on nitrification and colourless sulfur bacteria led him to the discovery of the chemolithotrophic mode of life; his studies on the bacteria involved in the biogeochemical cycles of nitrogen, sulfur and iron and of soil microorganisms made him one of the founders of the science of microbial ecology.
Raman Spectroscopy of Catalysts
Authors: Bañares Miguel A. , Wachs Israel E. 
Published: March 2010

AbstractThis chapter focuses on the application of Raman spectroscopy for characterizing catalytic materials and for the investigation of the bulk and surface chemistry occurring during catalyst preparation and operation; a general theoretical background and description of equipment for Raman experimentation is also presented. Over the past decades, Raman spectroscopy has increasingly been applied for characterization of all types of catalytic materials: bulk and supported metals, bulk mixed metal oxides, supported metal oxides, bulk and supported metal sulfides, zeolites and molecular sieves, heteropolyoxo anions, and clays. Raman is also used to study chemisorption and, in recent years, Raman has been increasingly applied under in situ conditions. There is an increasingly important strong driving force leading research toward the study of catalysts under reaction conditions. The last few years exhibit an increasing number of Raman studies during relevant reaction conditions (operando methodology). This momentum in reaction and operando Raman spectroscopy advances a new revolution in catalysis science that is poised to afford accurate molecular understanding of catalytic structure–activity/selectivity relationships.
Thermal Lens Spectroscopy
Authors: Franko Mladen , Tran Chieu D. 
Published: March 2010

Abstract
The thermal lens technique is based on measurement of the temperature rise that is produced in an illuminated sample as a result of nonradiative relaxation of the energy absorbed from a laser. Because the technique is based on direct measurement of the absorbed optical energy, its sensitivity is higher than conventional absorption techniques. However, advantages of the thermal lens technique are not only limited to its ultrasensitivity but also include other unique characteristics including small‐volume sample capability and dependency on thermo‐optical properties of solvents. In this overview, the theory of the technique is initially described. The main focus is, however, on the instrumentation and applications based on unique characteristics of the technique. Specifically, the discussion begins with a description of different types of thermal lens apparatuses (e.g. single‐beam and double‐beam instruments, differential, multiwavelength, thermal lens‐circular dichroism instruments, and thermal lens microscope). A detailed description of various applications including applications based on its ultratrasensitivity (e.g. applications in environment, agriculture and food science, biochemistry and biomedicine, measurements in the near‐ and middle‐infrared region, and kinetic determination), applications based on its small‐volume capability (microfluidic devices, detection for capillary electrophoresis), and applications based on exploitation of its dependency on thermal physical properties of solvents to either determine physical properties of the solvent or to further enhance the sensitivity of the technique follows. Finally, the future of the technique is forecasted.
High‐resolution Continuum Source Atomic Absorption Spectrometry—Theory and Applications
Authors: Welz Bernhard , Vale Maria Goreti R. , Florek Stefan , Okruss Michael , Huang Mao‐Dong , Becker‐Ross Helmut 
Published: March 2010

AbstractHigh‐resolution continuum source atomic absorption spectrometry (HR‐CS AAS) is probably the most innovative technique in the field of atomic spectrometry since the introduction of inductively coupled plasma mass spectrometry (ICP‐MS) in the 1980s. Although it uses the basic principle of atomic absorption spectrometry (AAS), i.e. the absorption of radiation by atoms in the gas phase, HR‐CS AAS should not just be considered an improved AAS, but a new technique with an impressive number of new features. HR‐CS AAS is a new player in the field of atomic spectrometry and has to be compared with all the other techniques that are available. We give a short historical introduction about the development of HR‐CS AAS since the 1960s, although it was only in the 1990s, when components that are essential for the proper performance of this technique became available. Theoretical considerations are treated to the extent that is necessary to understand the basic difference between LS AAS (line source atomic absorption spectrometry) and HR‐CS AAS. This is followed by a comprehensive treatment of the instrumental details from the continuum radiation source over the high‐resolution monochromator to the array detector, giving also an insight into the essential control functions to guarantee troublefree operation. The special features of HR‐CS AAS are discussed in detail in order to make possible a comparison with the other techniques of atomic spectrometry. One of these features is the possibility to determine nonmetals, such as phosphorus, sulfur, and the halogens using molecular absorption “lines”. In Section 5, it is shown that HR‐CS AAS, in combination with a graphite tube atomizer, is probably the most rugged technique for trace‐element determination currently available.
Acetic Acid Bacteria, Biotechnological Applications
Authors: De Vero Luciana , Gullo Maria , Giudici Paolo 
Published: March 2010

AbstractAcetic acid bacteria are a heterogeneous group of Gram‐negative, aerobic, rod‐shaped acidophilic bacteria known for a long time for their detrimental as well as beneficial role in fermented beverages and more recently as bacteria useful in many biotechnological processes. In the following sections, an overview of taxonomy, genome structure and metabolism has been described. Furthermore, recent investigations regarding biotechnological applications as well as food and beverage implications have been reported.
Biosensors, Color‐Sensitive
Authors: Lensu Lasse , Parkkinen Sinikka , Parkkinen Jussi 
Published: March 2010

AbstractBiosensors are devices that are used to detect chemical compounds by the use of biochemical reactions or use biomolecules as a sensing agent. The reactions are enabled by a biological component such as an enzyme, organelle, or even a whole cell. In the sensors, the biochemical activity is detected and measured by using electrical, thermal or optical phenomena, and the typical output is an electric signal. The state‐of‐the‐art sensors enable advanced applications such as sensitive molecular kinetics measurements and label‐free detection of certain molecules, for example, DNA or single proteins.Color‐sensitive biosensors are transducers sensitive to light and to the chemical medium of the biomolecules used in the light‐induced reactions. Photoactive biomolecules have been used in color‐sensitive biosensors generating an electrical and optical response dependent on the incident light spectrum. In this article, the focus is on color‐sensitive optoelectronic biosensors based on bacteriorhodopsin (BR).BR is the only protein in the purple membrane (PM) ofHalobacterium salinarium. It has a significant role in the energy balancing mechanism of the archaean since it produces a proton gradient across the cell membrane by the light‐induced BR photocycle. This enables the halobacterium to utilize light energy under unaerobic conditions.Because of its sophisticated electro‐optical properties, BR has been proposed to a variety of applications. The applications utilize either the charge transport, photochromic, photoelectric, or other optical properties. Most proposals are related to information storage and processing, but also light detection, artificial retinas, and even desalination of seawater have been within the research interest.
Cell Cycle in Suspension Cultured Plant Cells
Authors: Fowler Mark Richard 
Published: March 2010

AbstractCell division and the cell cycle are fundamental processes that are well, though not absolutely, conserved in all eukaryotes. Suspension cultured plant cells that can be synchronized offer the ideal experimental system in which to study the events and controls of the plant cell division cycle. As would be expected, the events during and controls of the plant cell division cycle appear to be very similar to those in other multicellular eukaryotes; there are, however, some important differences in both the processes during the cell division cycle and the controls that act on the cell division cycle. These differences may reflect the unique physical processes that accompany cell division in plants, the unique developmental patterns of plants or the differing signaling pathways utilized by plants to coordinate growth, division, and development.
Chinese Hamster Ovary Cells, Recombinant Protein Production
Authors: Hacker David L. , Chenuet Sébastien , Wurm Florian M. 
Published: March 2010

AbstractRecombinant therapeutic proteins represent a major class of biopharmaceuticals. They are produced in various hosts including bacteria, yeast, cultivated mammalian and plant cells, and transgenic plants and animals. Chinese hamster ovary (CHO) cells are the most widely used mammalian host for their production. Currently, about one‐third of all approved recombinant therapeutic proteins are produced in this cell line. This article is a summary of the molecular and cellular processes involved in therapeutic protein production with an emphasis on the generation and cultivation of recombinant CHO cell lines.
Algal Hydrogen Production
Authors: Ghirardi Maria L. , Kosourov Sergey , Maness Pinching , Smolinski Sharon , Seibert Michael 
Published: March 2010

AbstractDirect photosynthetic production of hydrogen from water has the theoretical potential to totally displace gasoline used in the United States, while requiring only about 0.12% of the continental land area. This article presents an overview of the metabolic pathways and enzymes utilized by algae and other microbes to generate H2, the barriers currently preventing practical application of these processes, and the current research approaches under investigation to overcome these barriers. The major barrier is the sensitivity of the H2‐producing catalyst ([FeFe]‐hydrogenase) to O2produced by photosynthesis, and a variety of approaches are being pursued to address this challenge at the molecular level. The development of photobiological H2‐production systems gained worldwide attention in 2000 with the observation that sulfur‐deprivedChlamydomonas reinhardtiicultures become anaerobic in the light and photoproduce H2for up to 4 days. Since then this phenomenon has been explored extensively, and the results have led to major new insights into Chlamydomonas anaerobic physiology and metabolism, as well as to other potential approaches to address other barriers to the practical application of photobiological H2production. These other barriers, which affect H2‐production efficiency, are also examined and include: (i) competition from other electron acceptors besides hydrogenases for photogenerated reductant at the level of reduced ferredoxin, (ii) down‐regulation of photosynthetic electron transport activity under H2‐producing conditions, (iii) the occurrence of state transitions which waste photons, and (iv) the low light‐saturation level of photosynthesis compared to the solar resource. Additional strategies to lower the potential cost of biohydrogen from algae are also examined. They include issues associated with photobioreactors; dark, fermentative H2production; and various types of integrated systems, which combine both dark and light‐driven H2‐production processes.
Immuno‐Flow Injection Analysis (FIA), Process Monitoring and Control
Authors: Rhee Jong Il 
Published: March 2010

AbstractFlow injection analysis (FIA) is a technique that allows the automatic analysis of many samples and offers high sensitivity and accuracy. It has been combined with a variety of analytical methods such as chemical and biological assays. Immunoassays that recognize and bind antibody (Ab) to antigen (Ag) usually require multiple steps such as washing and incubation, which make them time‐consuming. The FIA technology has been combined with the immunoassays to achieve high throughput and better control of the analytical process. A variety of immuno‐FIAs have been developed and used for the monitoring of drugs, pesticides, steroids, hormones and other high‐molecular weights products in biological processes. The use of immuno‐FIA for process monitoring and control have often been reported in biotechnology. This article presents immuno‐FIA technology based on homogeneous and heterogeneous immunoassays systematically and its application to the monitoring and control of biotechnological processes.
Preparation‐Condition Dependence of Hybrid SiO2‐Coated CdTe Nanocrystals with Intense and Tunable Photoluminescence
Authors: Yang Ping , Murase Norio 
Published: March 2010

AbstractWhen aqueously prepared CdTe nanocrystals (NCs) are coated with a SiO2 shell containing Cd ions and a sulfur source, they show a drastic increase in photoluminescence (PL) efficiency with a significant red shift and spectral narrowing after reflux. This is ascribed to the creation of a hybrid structure characterized by the formation of CdS‐like clusters in the vicinity of the NCs in the SiO2 shell. Since these clusters are close to the NCs, their effective size increases to reduce the quantum size effect. The dependences of the PL properties on the preparation conditions are systematically investigated. The PL efficiency increases from 28% to 80% in the best case with a red shift of 80 nm. The PL behaviors differ from those of normal CdTe NCs and include less temperature quenching and longer PL lifetime. The SiO2 coating enables bioconjugation with IgG without deterioration of PL efficiency, making hybrid NCs amenable for bioapplication.
Protective role of aquaporin‐4 water channels after contusion spinal cord injury
Authors: Kimura Atsushi , Hsu Mike , Seldin Marcus , Verkman Alan S. , Scharfman Helen E. , Binder Devin K. 
Published: March 2010

AbstractObjectiveSpinal cord injury (SCI) is accompanied by disruption of the blood‐spinal cord barrier and subsequent extravasation of fluid and proteins, which results in edema (increased water content) at the site of injury. However, the mechanisms that control edema and the extent to which edema impacts outcome after SCI are not well elucidated.MethodsHere, we examined the role of aquaporin‐4 (AQP4) water channels after experimental contusion injury in mice, a clinically relevant animal model of SCI.ResultsMice lacking AQP4 (AQP4−/− mice) exhibited significantly impaired locomotor function and prolonged bladder dysfunction compared with wild‐type (WT) littermates after contusion SCI. Consistent with a greater extent of functional deterioration, AQP4−/− mice showed greater neuronal loss and demyelination, with prominent cyst formation, which is generally absent in mouse SCI. The extent of spinal cord edema, as expressed by percentage water content, was persistently increased above control levels in AQP4−/− mice but not WT mice at 14 and 28 days after injury. Immunohistochemical analysis indicated that blood vessels in the vicinity of the lesion core had incomplete barrier function because of sparse tight junctions.InterpretationThese results suggest that AQP4 plays a protective role after contusion SCI by facilitating the clearance of excess water, and that targeting edema after SCI may be a novel therapeutic strategy. ANN NEUROL 2010;67:794–801
Flüssigkeitschromatographie – ihre Entwicklung und Bedeutung für die Lebenswissenschaften
Authors: Unger Klaus K. , Ditz R. , Machtejevas E. , Skudas R. 
Published: March 2010

AbstractFlüssigkeitschromatographische Methoden umfassen den breitest heute vorstellbaren Anwendungsbereich. Dies wird nirgendwo so deutlich wie in den Lebenswissenschaften, wenn es darum geht, Krankheitsmechanismen aufzuklären und komplexe Gemische bis in den Femtomol‐Bereich zu analysieren. Auf der anderen Seite besteht Bedarf an hochreinen therapeutischen Wirkstoffen, die als Pharmaka auf den Markt kommen und hohen Reinheitsanforderungen genügen müssen. Diese Aufreinigung wird mithilfe der Prozesschromatographie im Tonnenmaßstab bewerkstelligt. Die hohe Komplexität und breiten Konzentrationsbereiche biologischer Systeme in Kombination mit den extremen Reinheitsanforderungen der Arzneimittelproduktion sind die Herausforderungen, auf die die Flüssigchromatographie heute, nach mehr als einem Jahrhundert der Forschung und Entwicklung, erfolgreich reagiert hat. Noch immer sind aber ein tiefergehendes Verständnis der grundlegenden Phänomene sowie deren effiziente Nutzung für die Verbesserung der Lebensqualität notwendig.
Liquid Chromatography—Its Development and Key Role in Life Science Applications
Authors: Unger Klaus K. , Ditz R. , Machtejevas E. , Skudas R. 
Published: March 2010

AbstractLiquid chromatographic methods cover the broadest range of applications imaginable today. Nowhere is this more evident and relevant than in the life sciences, where identification of target substances relevant in disease mechanisms is performed down to the femtomole level. On the other hand, purification of therapeutic drugs on a multi‐ton scale is performed by process LC. The complexity and abundance range of biological systems in combination with the extreme purity requirements for drug manufacturing are the challenges that can be mastered today by chromatography, after more than a century of research and development. However, significant improvement is still required for a better understanding of the scientific fundamentals of the underlying phenomena and exploiting those for an enhanced quality of live.