bluuebunny/crossref_metadata_2025 huggingface dataset:
Radionuclides: Natural
Authors: Larivière Dominic , Guérin Nicolas
Published: June 2010

The natural ionizing radiation present on our planet comes from many sources and generates most of the radioactivity that surrounds us. Primordial radionuclides, defined as radionuclides present since the formation of Earth about 4.6 × 109years ago, play a critical role in our understanding of geological conditions on our planet over its whole history. Radioactivity initiated by the successive decay of232Th,235U, and238U is essentially responsible for the presence of radioisotopes of lead, polonium, bismuth, astatine, radon, francium, radium, and protactinium on Earth. Because of their short half‐lives with respect to Earth's geologic timescale, the decay of these radionuclides is responsible for a significant portion of the doses of natural radioactivity received by humans. Cosmic radiation, originating from both within and beyond our solar system, completes the list of significant modes of production of natural radioactivity in the atmosphere and the lithosphere. Minor sources of natural radioactivity (including radionuclides produced by cosmic neutron bombardments and spontaneous fission in uranium and thorium minerals) are known to generate quantities of transuranium isotopes and fission products, which are generally associated with the development of nuclear power.
Speciation: Radionuclides
Authors: Salbu Brit
Published: June 2010

To assess the environmental impact of radioactive contamination of different ecosystems, information on source terms, mobility, biological uptake, and associated effects is needed. However, naturally occurring and artificially produced radionuclides can be present in different physicochemical forms (ions, colloids, nanoparticles, pseudocolloids, particles) influencing the mobility and biological uptake. Following severe nuclear events associated with the nuclear weapon or fuel cycles, a major fraction of refractory radionuclides will be present as radioactive particles; radionuclides are also present as colloids or low molecular mass (LMM) ionic species in effluents from nuclear installations. Thus, the distribution of radionuclide species depends on the source and release scenarios. LMM radionuclide species are believed to be mobile and potentially bioavailable, while high molecular mass (HMM) species such as nanoparticles, colloids, polymers, and pseudocolloids are mobile in water. Radioactive particles are considered biologically inert, but can be retained in filtering organisms as well as in soils and sediments. If mobile species are present, ecosystem transfer is relatively fast, whereas the ecosystem transfer is delayed if particles are present. Owing to time‐dependent transformation processes such as interactions of mobile and reactive radionuclide species with components in soils and sediments or particle weathering and subsequent remobilization of associated radionuclide species, the original distribution of radionuclides deposited in ecosystems will change over time. Therefore, information on radionuclide species released and deposited, as well as on time‐dependent transformation processes influencing the distribution of radionuclide species, is essential for the assessment of the environmental impact and risk associated with radionuclide contamination. This article summarizes available speciation techniques that should be utilized within radioecology, including fractionation and solid‐state speciation, to characterize radionuclide species in waters, soils, and sediments.
Tritium: Radionuclide
Authors: Galeriu Dan , Melintescu Anca
Published: June 2010

Tritium is the heavy isotope of hydrogen and can therefore participate directly in a wide range of biological functions. It is formed through natural processes but is also generated through human activity in nuclear reactors, fusion, and weapons. In addition, it has some commercial applications. Its occurrence, chemical and physical properties, and speciation are unique in comparison to other radionuclides. This article summarizes what is currently known about tritium with regard to the isotope's occurrence, chemistry, speciation, remediation, separation, and the analytical techniques used for its detection and quantification. The potential impact of tritium on human health is also described.
Strontium: Radionuclides
Authors: Guillén Francisco Javier , Baeza Antonio , Salas Alejandro
Published: June 2010

Strontium has several radioactive isotopes, with90Sr being the most important in the environment. This radionuclide dispersed worldwide as a consequence of the atmospheric nuclear weapon tests in the 1960s, and is locally enhanced owing to the accidents involving radioactive material.90Sr is a pure β‐emitter and it may be detected by several detection techniques (gas‐flow proportional, liquid scintillation, Cerenkov counting, and ICP‐MS), after an appropriate radiochemical separation. The environmental behavior of radiostrontium is governed by its chemical similarities to calcium. It is usually associated with the mobile and bioavailable fractions in soils, and with the low MW fraction in aquatic ecosystems. The potential human exposure to radiostrontium is mainly due to the ingestion of food, milk and cereals being the two major sources. This exposure can be reduced to some extent by the addition of calcium fertilizers to minimize the soil‐to‐plant transfer of radiostrontium, and by increasing cattle calcium intake to decrease the90Sr content in milk.
Lead: Radionuclides
Authors: Sabuti Asnor Azrin , Rahim Mohamed Che Abd
Published: June 2010

Lead (Pb) is a highly toxic and radiogenic metal. It occurs naturally in the Earth, but is not very abundant. Even so, lead isotopes have been very useful ss tracers in glaciology, limnology, oceanography, and in atmospheric studies of global (transboundary) and local pollution. The dominant radioisotope of lead is210Pb, a very ubiquitous secondary radionuclide that is formed from238U decay via222Rn.210Pb originates from the Earth's crust, through the decay of226Ra. There are many factors that complicate the behavior of210Pb in soil, air, and water. Owing to these, a great deal of effort has been devoted to the quantitative determination of lead isotopes over the past few years. The separation and counting techniques for lead need to be rapid, convenient, and precise, and utilize very small amounts of material. Humans are exposed to lead through ingestion and inhalation, and it is stored for long periods of time mainly in bone and teeth. Thus, more studies on environmental exposures to lead need to be conducted, particularly for air monitoring, dust, water, and soil sampling, and lead‐based product sampling.
Polonium: Radionuclides
Authors: Alam Lubna , Rahim Mohamed Che Abd
Published: June 2010

All polonium isotopes are radioactive with only three having appreciable half‐lives:
208
Po,
209
Po, and
210
Po. It is a highly toxic element and is a health hazard if taken into the body. Polonium is a naturally occurring radionuclide and is present in the environment and in people at very low concentrations. Polonium concentrations in the environment can vary by orders of magnitude.
210
Po concentration in soil varies according to soil strata, depth, sedimentation and biological processes, fertilization and pH. Incomplete burning of fuels of coal loading plays an important role in the concentration of
210
Po in air. Usually, the activity concentration of
210
Po in surface air is low. Polonium can be separated by irradiating stable bismuth‐209 with thermal neutrons resulting in the formation of radioactive
210
Bi, which decays into
210
Po.
Xenon: Radionuclides
Authors: Saey Paul R.J.
Published: June 2010

Radioxenon isotopes are noble gases mainly produced in nuclear fission e.g., uranium‐235. In nuclear medicine, xenon‐133 isotopes are used for measuring the physiological parameters of lung ventilation and to image the lungs. They are further used in isotonic solutions to image blood flow, particularly cerebral blood flow. Most radioactive isotopes of this element are produced by a nuclear fission reaction of uranium‐235, uranium‐238, or plutonium‐239. Xenon‐133 is the most abundant radioxenons observed in environmental samples, although contributions of131mXe and135Xe can be determined down to a few percent of the total β‐activity. The minimum detectable concentration (MDC) for133Xe in routine samples is about 1 mBq m−3. This article will describe the production, applications, occurrence, and measurement of the various xenon isotopes.
Radon: Radionuclides
Authors: Tracy Bliss L.
Published: June 2010

Radon is a naturally occurring radioactive gas formed by the decay of uranium and thorium in the Earth's crust. At atomic number 86, it is the heaviest member of the noble or inert gas family, which also includes helium, neon, argon, krypton, and xenon. Unlike the other members of the family, radon has no stable isotopes. Of the 34 known radioactive isotopes of radon, only three are supported by the decay of primordial radionuclides, and only two occur with any significant abundance in nature. The three isotopes, along with their half‐lives, are222Rn (3.8235 days),220Rn (55.6 s), and219Rn (3.96 s). Both222Rn and220Rn decay by the emission of α‐particles and give rise to a number of short‐lived progeny.222Rn and220Rn are the only ones regarded as having any health impacts and this is due to their short‐lived progeny—218Po,214Pb,214Bi, and214Po from222Rn;216Po,212Pb,212Bi,212Po, and208Tl from220Rn. Being a gas, radon diffuses readily into the atmosphere and may build up to hazardous concentrations in confined spaces in homes and underground mines. Radon is the largest single contributor to natural background radiation exposure worldwide. Radon is now recognized as the second leading cause of lung cancer, following tobacco smoking, and is responsible for up to 20 000 deaths per year in the United States and 1900 deaths per year in Canada. Many countries have now established programs to reduce radon exposures to the population.
Europium: Radionuclides
Authors: Wang Xiangke , Li Jiaxing
Published: June 2010

The physicochemical behavior of europium in the environment and the speciation of europium under different experimental conditions are described. The behavior and speciation of Eu(III) in the environment are dominated by the surface properties of solid particles, presence of natural organic and inorganic materials, pH values of the systems, and other parameters. Europium can be characterized and analyzed by spectrophotometry, polarography, atomic adsorption spectrometry (AAS), atomic emission spectrometry (AES), atomic fluorescence spectrometry (AFS), atom mass spectrometry (AMS), X‐ray fluorescence spectrometry (XFS), neutron activation analysis (NAA), and liquid scintillation counting (LSC).
Protactinium: Radionuclides
Authors: Hasan Asamuddin Abu , Rahim Mohamed Che Abd
Published: June 2010

Protactinium (Pa) is one of the rarest elements that can be found or extracted from the natural source. Protactinium can be found in soil, rocks, water, plants, and animals, but in a very low concentration. There are no uses outside of basic and experimental scientific research and no commercial applications for protactinium.
231
Pa is the most important natural isotope, while
223
Pa is the only artificial isotope.
231
Pa has become important to the scientists because
231
Pa/
230
Th in the ocean can perform as an ocean circulation proxy. Because of its low concentrations, measurement of protactinium using thermal ionization mass spectrometry (TIMS) has become the finest and most promising technique.
PacificOcean: Radionuclides
Authors: Aoyama Michio
Published: June 2010

The main sources of anthropogenic radioactivity to the Pacific Ocean are fallout from atmospheric nuclear weapon testing. The releases from the nuclear fuel reprocessing plant and from the Chernobyl accident in 1986 are minimal in this region. Consequently, the radionuclide levels in the Pacific Ocean are low, about a few becquerel per cubic meter for137Cs in the surface water.

137Cs,239, 240Pu (other transuranics), and90Sr are discussed in this article for the following reasons: (i)137Cs and90Sr, conservative in the open sea, are the most abundant anthropogenic radionuclides and the main contributors to human exposure and (ii)239, 240Pu are very long‐lived, nonconservative, and the most abundant among transuranics. The distributions and temporal change in these radionuclides in seawater and sediment are described. The current radionuclide levels in the Pacific Ocean are low and, therefore, of no concern from the radiological point of view.
A
tlantic
O
cean: Radionuclides
Authors: Kershaw Peter
Published: June 2010

This article summarizes the main sources and the fate of radionuclides in the Atlantic Ocean, resulting primarily from human activity. This covers direct and indirect sources of artificial radionuclides due to global fallout from weapons testing, controlled releases from nuclear establishments, the deliberate disposal of radioactive waste, accidental inputs, and the presence of naturally occurring radionuclides, sometimes in enhanced quantities due to human activities. The distribution and behavior of radionuclides in seawater, sediments, and biota are described, being a consequence of both the nature of the source term and the fundamental properties of the radionuclides (chemical behavior, half‐life). Finally, the article considers the radiological consequences due to the principal sources responsible for the maximum dose to the human population: nuclear fuel reprocessing and naturally occurring radionuclides.
OakRidgeReservation: Radionuclides
Authors: Jardine Philip M. , Brooks Scott C. , Watson David B.
Published: June 2010

The Department of Energy (DOE) facilities on the Oak Ridge Reservation (ORR) have a rich history of radionuclide separation technologies and research involving the conversion of uranium to plutonium for thermonuclear weapon parts during WWII and the Cold War era. During this period, tens of millions of curies of radioactive waste was typically disposed in unlined surface impoundments and shallow subsurface trenches. The disposal methods have resulted in a daunting challenge of remediating huge below‐ground inventories of legacy radioactive waste, since the scale of the problem is at the watershed level. The focus of this article is to provide an overview of past and current activities on the ORR that involve the use, disposal, and remediation of radionuclide isotopes. The aim of the article is to provide an improved understanding of why radioactive material was generated, how it was used and disposed of, and how it continues to interact with the environment.
B
altic
S
ea: Radionuclides
Authors: Nielsen Sven P. , Lüning Maria , Ilus Erkki , Outola Iisa , Ikäheimonen Tarja , Mattila Jukka , Herrmann Jürgen , Kanisch Günter , Osvath Iolanda
Published: June 2010

The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of
137
Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout about 14%. For
90
Sr in the Baltic Sea, input from atmospheric fallout from nuclear weapons tests has contributed about 81%, while the contribution from Chernobyl fallout was about 13%. Cesium‐137 is the main indicator of Baltic seawater with respect to anthropogenic radioactivity. The highest concentrations in seawater during 1999–2006 were found in the Baltic Proper and the Bothnian Sea. The general trend is steadily decreasing. Concentrations of anthropogenic radioactivity in fish generally show decreasing trends in agreement with concentrations in seawater. Among freshwater fish, pike showed large
137
Cs values due to their higher concentration factors (CFs). The larger
137
Cs values of pike were observed at the coast of the Bothnian Sea. The Baltic Sea is the regional sea in the world with the highest concentrations of
137
Cs. The Baltic Sea ranks third in the world with respect to
90
Sr in seawater; only the Irish Sea and the Black Sea show higher levels. In 1990, average concentrations of
137
Cs in fish from the Baltic Sea were similar to those in the Irish Sea, about 4 times higher than in the Black Sea and about 30 times higher than in the Mediterranean Sea.
BlackSea: Radionuclides
Authors: Egorov Victor , Gulin Sergey , Polikarpov Gennady , Osvath Iolanda
Published: June 2010

Anthropogenic radionuclide pollution of the Black Sea originated primarily from the atmospheric nuclear weapon tests carried out during the late 1950s and early 1960s before the signing of the Test Ban Treaty in 1963, and after the Chernobyl nuclear power plant (NPP) accident in April 1986. Chernobyl atmospheric fallout deposited 1.7–2.4 PBq of137Cs into the Black Sea surface, which temporarily increased the137Cs inventory of the 0–50 m surface layer by a factor of 6–10 in comparison with its pre‐Chernobyl value. The contribution of Chernobyl‐origin90Sr (0.1–0.3 PBq) from atmospheric fallout was lower in comparison with that of137Cs. A subsequent90Sr input from the Danube and the Dnieper Rivers (about 0.16 PBq) was an important contribution to the budget of this radionuclide in the Black Sea, while the riverine137Cs input (0.02–0.03 PBq) was insignificant. The decrease of the137Cs inventory in the surface layer after Chernobyl accident has been mainly controlled by vertical mixing, loss through the Bosporus Strait, and radioactive decay. The loss through the Bosporus accounted for 2–2.5% of the137Cs inventory. In the case of90Sr, these processes have been compensated by river inputs from the Dnieper and Danube up to 1994–1995 and partially after 2000. The vertical mixing of137Cs and90Sr was mainly effective within the 0–200 m layer. Sediment inventories of137Cs in the Danube and Dnieper delta regions exceeded by one order of magnitude the values in the slope zone and two orders of magnitude those in the deep basin. Because of the self‐cleaning processes, the current levels of anthropogenic radionuclides are relatively low in all the components of the Black Sea environment, and therefore do not pose any radiological problem. Doses to marine biota from137Cs and90Sr are several orders of magnitude lower than those from natural210Po.
Polymeric Membranes for Energy Applications
Authors: Low Bee Ting , Wang Yan , Chung Tai‐Shung
Published: June 2010

The volatile and escalating oil prices, combined with the environmental consequences of anthropogenic carbon dioxide emissions, have led to the growing interest in the development of alternative energy sources. The world energy consumption continues to be at the core of the climate change debate and the use of natural gas and fossil‐derived hydrogen is recommended to alleviate global warming. In the long run, biofuel represents an important renewable resource for attaining energy sustainability. Membrane technology is a promising separation technique for natural gas, hydrogen, and biofuel purifications. Polymeric membranes remain the most viable commercial choice and substantial research works on the design of polymers with improved separation performance and physicochemical properties are in progress. Various approaches have been utilized by membrane scientists to overcome the bottlenecks and to achieve this goal. In this review, a critical survey on polymeric membranes for gas separation and pervaporation in energy‐related applications is presented. The merits and deficiencies of existing polymeric membrane are evaluated. The vital aspects of membrane process design and the future prospects of membrane‐based separations are highlighted.
Absorption and Luminescence Probes
Authors: Rusin Oleksandr , Strongin Robert M. , Lim Soojin
Published: June 2010

Absorption and luminescent probes are compounds with an extensive variety of molecular structures. Despite their diversity and variations in their properties, they possess many similar general features. In solution they can form specific complexes with targets, leading to corresponding measurable changes in photophysical properties. Depending on the particular research need, there is a large choice of available probes absorbing and emitting light in ultraviolet (UV), visible, or near infrared (NIR) spectral ranges. They have been commonly used, for example, for pH measurements, the detection of gases, cations or anions, in the screening of metabolites, in monitoring macromolecular transformations, as well as in numerous other related chemical and biochemical processes.
Energy Dispersive, X‐Ray Fluorescence Analysis
Authors: Wobrauschek Peter , Streli Christina , Selin Lindgren Eva
Published: June 2010

Energy‐dispersive X‐ray fluorescence (EDXRF) is an analytical method for qualitative as well as quantitative determination of elements in a sample, independent of their chemical form. It is built on the fact that elements that are irradiated with high‐energetic X‐rays have a certain probability of emitting characteristic X‐rays, the energies of which are unique for each element. In the energy‐dispersive (ED) systems, the emitted X‐rays are detected via their energies. The use of the EDXRF technique has accelerated since the 1960s as a result of the development of liquid nitrogen cooled solid‐state detectors, nuclear electronics, and small computers. Nowadays compact light‐weight electrically cooled detectors are available, which, together with air‐cooled low‐power X‐ray tubes, are perfectly suited for handheld spectrometers. EDXRF is multielemental and nondestructive and can be applied to large as well as small samples of different composition and character. If conditions are optimized, minimum detection limits can be below the nanogram absolute or micrograms per gram concentration level for small laboratory instruments and into the femtogram or nanograms per milliliter region for more advanced instrumentation (total reflection X‐ray fluorescence (TXRF), synchrotron radiation).

EDXRF spectrometers exist at many degrees of sophistication, ranging from advanced laboratory instruments to small portable instruments for field observations. They can be designed for analysis of bulk material or for scanning and elemental mapping of small areas. The use of X‐ray optics like single or polycapillaries and curved mirrors in Kirkpatrick–Baez geometry lead to X‐ray spot sizes of micrometers and below ideally suited for micro‐XRF. Mapping with high spatial resolution is thus possible opening investigations down to cell dimension.

Typical applications for EDXRF are analysis of agricultural material, medical samples, archaeological and historical objects, painting and fine art objects, and environmental samples such as soil, ores, water, and aerosol particles.
Nanomaterials for Electroanalysis
Authors: Merkoçi Arben , Ambrosi Adriano , de la Escosura‐Muñiz Alfredo , Pérez‐López Briza , Guix Maria , Maltez Marisa , Marin Sergio
Published: June 2010

The emergence of nanotechnology and nanomaterials has opened up new horizons for the development of improved analytical devices. New synthesis, fabrication, and characterization methods offer the possibility to control the size, shape, and composition of nanometric‐scale materials, thereby allowing exquisite control of their properties. The ability to carefully tailor the physical properties of nanomaterials is probably the major achievement of nanoscience and represents an essential element for their application in analytical systems.

Among the numerous detecting strategies, electrochemical sensing techniques play a growing role in various fields in which an accurate, low‐cost, fast, and online analytical measuring system is required. Besides the relatively low cost compared with optical instrumentation, advantages such as the possibility of miniaturization as well as in‐field applications make electrochemical sensing devices very attractive.

The properties of nanostructured materials, such as high surface/volume ratio, their ability to be functionalized, favorable electronic and thermal features, and electrocatalytic effect attracted considerable attention for the assembling of novel electrochemical sensing systems. Nanomaterials such as nanoparticles (NPs), nanotubes, nanowires, nanocomposites, and nanochannels of various sizes and compositions have been applied in electroanalysis to improve the immobilization of enzymes, antigens, and nucleic acids on electrochemical transducer surfaces, to promote the direct electron‐transfer reactions, and to amplify and orient the analytic signal of biorecognition events. In this article, a general description of the properties of the nanomaterials most commonly used in electroanalysis, along with their integration into electrochemical analytical tools, is given. The analytical performances and the impact such nanomaterial‐based devices are expected to have upon clinical diagnostics, environmental monitoring, security surveillance, and food safety are also discussed.
Nanoimprint Lithography for Functional Three‐Dimensional Patterns
Authors: Ofir Yuval , Moran Isaac W. , Subramani Chandramouleeswaran , Carter Kenneth R. , Rotello Vincent M.
Published: June 2010

Nanoimprint lithography (NIL) is viewed as an alternative nanopatterning technique to traditional photolithography, allowing micrometer‐scale and sub‐hundred‐nanometer resolution as well as three‐dimensional structure fabrication. In this Research News article we highlight current activities towards the use of NIL in patterning active or functional materials, and the application of NIL in patterning materials that present both chemistry and structure/topo­graphy in the patterned structures, which provide scaffolds for subsequent manipulation. We discuss and give examples of the various materials and chemistries that have been used to create functional patterns and their implication in various fields as electronic and magnetic devices, optically relevant structures, biologically important surfaces, and 3D particles.
Accuracy of phenotyping of autistic children based on internet implemented parent report
Authors: Lee Hane , Marvin Alison R. , Watson Tamara , Piggot Judith , Law J. Kiely , Law Paul A. , Constantino John N. , Nelson Stanley F.
Published: June 2010

While strong familial evidence supports a substantial genetic contribution to the etiology of autism spectrum disorders (ASD), specific genetic abnormalities have been identified in only a small minority of all cases. In order to comprehensively delineate the genetic components of autism including the identification of rare and common variants, overall sample sizes an order of magnitude larger than those currently under study are critically needed. This will require rapid and scalable subject assessment paradigms that obviate clinic‐based time‐intensive behavioral phenotyping, which is a rate‐limiting step. Here, we test the accuracy of a web‐based approach to autism phenotyping implemented within the Interactive Autism Network (IAN). Families who were registered with the IAN and resided near one of the three study sites were eligible for the study. One hundred seven children ascertained from this pool who were verbal, age 4–17 years, and had Social Communication Questionnaire (SCQ) scores ≥12 (a profile that characterizes a majority of ASD‐affected children in IAN) underwent a clinical confirmation battery. One hundred five of the 107 children were ASD positive (98%) by clinician's best estimate. One hundred four of these individuals (99%) were ASD positive by developmental history using the Autism Diagnostic Interview‐Revised (ADI‐R) and 97 (93%) were positive for ASD by developmental history and direct observational assessment (Autism Diagnostic Observational Schedule or expert clinician observation). These data support the reliability and feasibility of the IAN‐implemented parent‐report paradigms for the ascertainment of clinical ASD for large‐scale genetic research. © 2010 Wiley‐Liss, Inc.
Vulnerability of the superficial zone of immature articular cartilage to compressive injury
Authors: Rolauffs Bernd , Muehleman Carol , Li Jun , Kurz Bodo , Kuettner Klaus E. , Frank Eliot , Grodzinsky Alan J.
Published: June 2010

Objective

The zonal composition and functioning of adult articular cartilage causes depth‐dependent responses to compressive injury. In immature cartilage, shear and compressive moduli as well as collagen and sulfated glycosaminoglycan (sGAG) content also vary with depth. However, there is little understanding of the depth‐dependent damage caused by injury. Since injury to immature knee joints most often causes articular cartilage lesions, this study was undertaken to characterize the zonal dependence of biomechanical, biochemical, and matrix‐associated changes caused by compressive injury.

Methods

Disks from the superficial and deeper zones of bovine calves were biomechanically characterized. Injury to the disks was achieved by applying a final strain of 50% compression at 100%/second, followed by biomechanical recharacterization. Tissue compaction upon injury as well as sGAG density, sGAG loss, and biosynthesis were measured. Collagen fiber orientation and matrix damage were assessed using histology, diffraction‐enhanced x‐ray imaging, and texture analysis.

Results

Injured superficial zone disks showed surface disruption, tissue compaction by 20.3 ± 4.3% (mean ± SEM), and immediate biomechanical impairment that was revealed by a mean ± SEM decrease in dynamic stiffness to 7.1 ± 3.3% of the value before injury and equilibrium moduli that were below the level of detection. Tissue areas that appeared intact on histology showed clear textural alterations. Injured deeper zone disks showed collagen crimping but remained undamaged and biomechanically intact. Superficial zone disks did not lose sGAG immediately after injury, but lost 17.8 ± 1.4% of sGAG after 48 hours; deeper zone disks lost only 2.8 ± 0.3% of sGAG content. Biomechanical impairment was associated primarily with structural damage.

Conclusion

The soft superficial zone of immature cartilage is vulnerable to compressive injury, causing superficial matrix disruption, extensive compaction, and textural alteration, which results in immediate loss of biomechanical function. In conjunction with delayed superficial sGAG loss, these changes may predispose the articular surface to further softening and tissue damage, thus increasing the risk of development of secondary osteoarthritis.
Prediction of human blood‐to‐plasma drug concentration ratio
Authors: Uchimura Takahide , Kato Motohiro , Saito Tomohisa , Kinoshita Haruki
Published: June 2010

The objective of this study was to predictRb(blood/plasma ratio) in humans using a simple method. Human and ratRband free fraction in plasma (fp) values were obtained from the literature. The ratio of total red blood cell concentration to the free concentration in plasma (Kb) was calculated usingfpandRb. Four methods were used for the prediction ofRb: (A) use of ratRb; (B) use ofRbcalculated from ratKband humanfp; (C) correlation of human log ((1−fp)/fp) and human logKb; and (D) correlation of logDwith human logKb. TheRbof 96 compounds in humans ranged from 0.52 to 2.00, with an average of 0.89. A significant correlation was observed among human logKb, human log ((1−fp)/fp), and logD; however, no obvious correlation was observed among humanRb, human log ((1−fp)/fp), and logD. The errors within 1.25‐fold for methods A–D were 68.3%, 77.6%, 61.5% and 64.8%, respectively. All predictive methods considered here were superior to the use of the average value of humanRborRb=1. RatRbcorrected by humanfpimproved the accuracy of the prediction. Method B was the most accurate of the four methods. Copyright © 2010 John Wiley & Sons, Ltd.
Hemoglobin regulates the metabolic and synthetic function of rat insulinoma cells cultured in a hollow fiber bioreactor
Authors: Gundersen Sharon I. , Chen Guo , Powell Heather M. , Palmer Andre F.
Published: June 2010

Pancreatic islet transplantation continues to benefit patients with type 1 diabetes by normalizing glucose metabolism and improving other complications of diabetes. However, islet transplantation therapy is limited by the inadequate availability of pancreatic islets. In order to address this concern, this work investigated the expansion of rat insulinoma cells (INS‐1) and their ability to generate insulin in a hollow fiber bioreactor (HFB). The long‐term goal of this project is to develop a bioartificial pancreas. HFBs were incubated at two different oxygenation conditions (10% and 19% O2) to determine the best scenario for O2 transport to cultured cells. Also, bovine hemoglobin (BvHb) was supplemented in the cell culture media of the HFBs in order to increase O2 transport under both oxygenation conditions. Our results show that INS‐1 cells expanded under all oxygenation conditions after 2 weeks of culture, with a slightly higher cell expansion under normoxic oxygenation (19% O2) for both control HFBs and BvHb HFBs. In addition, cellular insulin production remained steady throughout the study for normoxic control HFBs and BvHb HFBs, while it increased under hypoxic oxygenation (10% O2) for both types of HFBs but to different extents. Under the two different oxygenation conditions, cellular insulin production was more uniform with time in BvHb HFBs versus control HFBs. These results, along with qRT‐PCR analysis, suggest a possible dysregulation of the insulin‐signaling pathway under hypoxic culture conditions. In conclusion, the HFB culture system is an environment capable of expanding insulinomas while maintaining their viability and insulin production capabilities. Biotechnol. Bioeng. 2010;107: 582–592. © 2010 Wiley Periodicals, Inc.
Farnesol production from Escherichia coli by harnessing the exogenous mevalonate pathway
Authors: Wang Chonglong , Yoon Sang‐Hwal , Shah Asad Ali , Chung Young‐Ryun , Kim Jae‐Yean , Choi Eui‐Sung , Keasling Jay D. , Kim Seon‐Won
Published: June 2010

Farnesol (FOH) production has been carried out in metabolically engineered Escherichia coli. FOH is formed through the depyrophosphorylation of farnesyl pyrophosphate (FPP), which is synthesized from isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) by FPP synthase. In order to increase FPP synthesis, E. coli was metabolically engineered to overexpress ispA and to utilize the foreign mevalonate (MVA) pathway for the efficient synthesis of IPP and DMAPP. Two‐phase culture using a decane overlay of the culture broth was applied to reduce volatile loss of FOH produced during culture and to extract FOH from the culture broth. A FOH production of 135.5 mg/L was obtained from the recombinant E. coli harboring the pTispA and pSNA plasmids for ispA overexpression and MVA pathway utilization, respectively. It is interesting to observe that a large amount of FOH could be produced from E. coli without FOH synthase by the augmentation of FPP synthesis. Introduction of the exogenous MVA pathway enabled the dramatic production of FOH by E. coli while no detectable FOH production was observed in the endogenous MEP pathway‐only control. Biotechnol. Bioeng. 2010;107: 421–429. © 2010 Wiley Periodicals, Inc.
A microfluidic bioreactor with integrated transepithelial electrical resistance (TEER) measurement electrodes for evaluation of renal epithelial cells
Authors: Ferrell Nicholas , Desai Ravi R. , Fleischman Aaron J. , Roy Shuvo , Humes H. David , Fissell William H.
Published: June 2010

We have developed a bilayer microfluidic system with integrated transepithelial electrical resistance (TEER) measurement electrodes to evaluate kidney epithelial cells under physiologically relevant fluid flow conditions. The bioreactor consists of apical and basolateral fluidic chambers connected via a transparent microporous membrane. The top chamber contains microfluidic channels to perfuse the apical surface of the cells. The bottom chamber acts as a reservoir for transport across the cell layer and provides support for the membrane. TEER electrodes were integrated into the device to monitor cell growth and evaluate cell–cell tight junction integrity. Immunofluorescence staining was performed within the microchannels for ZO‐1 tight junction protein and acetylated α‐tubulin (primary cilia) using human renal epithelial cells (HREC) and MDCK cells. HREC were stained for cytoskeletal F‐actin and exhibited disassembly of cytosolic F‐actin stress fibers when exposed to shear stress. TEER was monitored over time under normal culture conditions and after disruption of the tight junctions using low Ca2+ medium. The transport rate of a fluorescently labeled tracer molecule (FITC‐inulin) was measured before and after Ca2+ switch and a decrease in TEER corresponded with a large increase in paracellular inulin transport. This bioreactor design provides an instrumented platform with physiologically meaningful flow conditions to study various epithelial cell transport processes. Biotechnol. Bioeng. 2010;107:707–716. © 2010 Wiley Periodicals, Inc.
Quantitative physiology ofPichia pastorisduring glucose‐limited high‐cell density fed‐batch cultivation for recombinant protein production
Authors: Heyland Jan , Fu Jianan , Blank Lars M. , Schmid Andreas
Published: June 2010

Pichia pastorishas become one of the major microorganisms for the production of proteins in recent years. This development was mainly driven by the readily available genetic tools and the ease of high‐cell density cultivations using methanol (or methanol/glycerol mixtures) as inducer and carbon source. To overcome the observed limitations of methanol use such as high heat development, cell lysis, and explosion hazard, we here revisited the possibility to produce proteins withP. pastorisusing glucose as sole carbon source. Using a recombinantP. pastorisstrain in glucose limited fed‐batch cultivations, very high‐cell densities were reached (more than 200 gCDW L−1) resulting in a recombinant protein titer of about 6.5 g L−1. To investigate the impact of recombinant protein production and high‐cell density fermentation on the metabolism ofP. pastoris, we used13C‐tracer‐based metabolic flux analysis in batch and fed‐batch experiments. At a controlled growth rate of 0.12 h−1in fed‐batch experiments an increased TCA cycle flux of 1.1 mmol g−1 h−1compared to 0.7 mmol g−1 h−1for the recombinant and reference strains, respectively, suggest a limited but significant flux rerouting of carbon and energy resources. This change in flux is most likely causal to protein synthesis. In summary, the results highlight the potential of glucose as carbon and energy source, enabling high biomass concentrations and protein titers. The insights into the operation of metabolism during recombinant protein production might guide strain design and fermentation development. Biotechnol. Bioeng. 2010;107: 357–368. © 2010 Wiley Periodicals, Inc.
Glycoside hydrolases: Catalytic base/nucleophile diversity
Authors: Vuong Thu V. , Wilson David B.
Published: June 2010

Recent studies have shown that a number of glycoside hydrolase families do not follow the classical catalytic mechanisms, as they lack a typical catalytic base/nucleophile. A variety of mechanisms are used to replace this function, including substrate‐assisted catalysis, a network of several residues, and the use of non‐carboxylate residues or exogenous nucleophiles. Removal of the catalytic base/nucleophile by mutation can have a profound impact on substrate specificity, producing enzymes with completely new functions. Biotechnol. Bioeng. 2010;107: 195–205. © 2010 Wiley Periodicals, Inc.
ChemInform Abstract: G2(MP2) Molecular Orbital Study of [H3AlXH3]‐ (X: C, Si, and Ge) and H3AlYH3 (Y: N, P, and As) Complexes.
Authors: Anane Hafid , Jarid Abdellah , Boutalib Abderrahim
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Crystal Structure of Ba5In3F19: A New Structural Type in Fluoride Crystal Chemistry.
Authors: De Kozak A. , Dupont N. , Gredin P. , Riou D.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ab initio Structures of (M2) and (M3) VO2 High Pressure Phases.
Authors: Galy J. , Miehe G.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Diammonium Titanium Pentafluoride, (NH4)2TiF5, Containing Ti3+.
Authors: Dadachov Mike , Eriksson Lars
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Manganese‐Rich Natural Franklinite.
Authors: Doriguetto Antonio C. , Fernandes Nelson G.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Orthorhombic InFe0.33Ti0.67O3.33.
Authors: Michiue Yuichi , Brown Francisco , Kimizuka Noboru , Watanabe Mamoru , Orita Masahiro , Ohta Hiromichi
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: An Illuminating Framework: Understanding the Photoluminescence of α‐Cu‐AlCl4.
Authors: Sullivan Roger M. , Martin James D.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Magnetic Excitations in Polyoxometalate Clusters Observed by Inelastic Neutron Scattering: Evidence for Ferromagnetic Exchange Interactions and Spin Anisotropy in the Tetrameric Nickel(II) Cluster [Ni4(H2O)2 (PW9O34)2]10‐ and Comparison with the Magnetic Properties.
Authors: Clemente‐Juan Juan M. , Andres Hanspeter , Borras‐Almenar Juan J. , Coronado Eugenio , Guedel Hans U. , Aebersold Michael , Kearly Gordon , Buettner Herma , Zolliker Markus
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Magnetic Excitations in Polyoxometalate Clusters Observed by Inelastic Neutron Scattering: Evidence for Anisotropic Ferromagnetic Exchange Interactions in the Tetrameric Cobalt(II) Cluster [Co4(H2O)2 (PW9O34)2]10‐. Comparison with the Magnetic and Specific Heat Properties.
Authors: Andres Hanspeter , Clemente‐Juan Juan M. , Aebersold Michael , Guedel Hans U. , Coronado Eugenio , Buettner Herma , Kearly Gordon , Melero Julio , Burriel Ramon
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ferromagnetism in Talc‐Like Cobalt‐Phyllosilicates.
Authors: Richard‐Plouet M. , Vilminot S.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Tetracyclohexyloxaquaterene.
Authors: Pajewski Robert , Pecak Agnieszka , Ostaszewski Ryszard , Jurczak Janusz
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: An o‐Xylyl Cross‐Bridged 5,12‐Dioxocyclam.
Authors: Hubin Timothy J. , Tyryshkin Nickolay , Alcock Nathaniel W. , Busch Daryle H.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Enantioselective Ring Opening of Meso Aziridines Catalyzed by Tridentate Schiff Base Chromium(III) Complexes.
Authors: Li Zhen , Fernandez Monica , Jacobsen Eric N.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Catalytic Enantioselective Conjugate Addition of 1,3‐Dicarbonyl Compounds to Nitroalkenes.
Authors: Ji Jianguo , Barnes David M. , Zhang Ji , King Steven A. , Wittenberger Steven J. , Morton Howard E.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Chiral Amine‐Catalyzed Asymmetric Baylis—Hillman Reaction: A Reliable Route to Highly Enantiomerically Enriched (α‐Methylene‐β‐hydroxy)esters.
Authors: Iwabuchi Yoshiharu , Nakatani Mari , Yokoyama Nobiko , Hatakeyama Susumi
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: 1,3‐Dipolar Cycloaddition of Dipolar Reagents to Bifunctional Olefins in the Presence of Chloramine‐T (CAT).
Authors: Padmavathi V. , Sumathi R. P. , Chandrasekhar Babu N. , Bhaskar Reddy D.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.