bluuebunny/crossref_metadata_2025 huggingface dataset:
The interaction between a manmade lake and groundwater: an example site in the Aurku area, Chiayi County, Taiwan
Authors: Ting Cheh‐Shyh , Jean Jiin‐Shuh , Tseng Chien‐Chang , Wu Ming‐Chee
Published: August 2006

The objectives of this study are (1) to understand the subsurface hydrology in the Aurku area, Chiayi County, southern Taiwan, and (2) to determine the interaction between the manmade lake and groundwater level through the recharge produced by infiltration by on‐site investigation and laboratory sand tank simulation. The manmade lake was selected as the field site for groundwater recharge effect so as to assess the role of infiltration from the aquaculture ponds in this area. These results can be used as reference for future application of constructing a series of manmade lakes. The field experiment was performed to measure the infiltration rate of the manmade lake by using the water balance method and double‐ring infiltration test. The results demonstrated that the manmade lake had helped the recharge of the groundwater. Raising or maintaining a higher water level of the manmade lake can promote higher infiltration. When the groundwater level is equal to or higher than the bottom of the manmade lake, infiltration will slow or cease. The field experiment and laboratory sand tank simulation demonstrated that the infiltration rate increased with the higher storage depth of the manmade lake. The laboratory simulation also indicated that while the groundwater level was lower than the bottom of manmade lake (i.e. the reference level) and the initial water depth (3 cm) was equal to or greater than 50% of the full water storage depth, the infiltration depth increased with time. However, the infiltration depth would be very small or nearly zero when the groundwater level was higher than the bottom of the manmade lake. Copyright © 2006 John Wiley & Sons, Ltd.
Ab initio QM/MM dynamics of H3O+ in water
Authors: Intharathep Pathumwadee , Tongraar Anan , Sagarik Kritsana
Published: August 2006

A molecular dynamics (MD) simulation based on a combined ab initio quantum mechanics/molecular mechanics (QM/MM) method has been performed to investigate the solvation structure and dynamics of H3O+ in water. The QM region is a sphere around the central H3O+ ion, and contains about 6–8 water molecules. It is treated at the Hartree‐Fock (HF) level, while the rest of the system is described by means of classical pair potentials. The Eigen complex (H9O) is found to be the most prevalent species in the aqueous solution, partly due to the selection scheme of the center of the QM region. The QM/MM results show that the Eigen complex frequently converts back and forth into the Zundel (H5O) structure. Besides the three nearest‐neighbor water molecules directly hydrogen‐bonded to H3O+, other neighbor waters, such as a fourth water molecule which interacts preferentially with the oxygen atom of the hydronium ion, are found occasionally near the ion. Analyses of the water exchange processes and the mean residence times of water molecules in the ion's hydration shell indicate that such next‐nearest neighbor water molecules participate in the rearrangement of the hydrogen bond network during fluctuative formation of the Zundel ion and, thus, contribute to the Grotthuss transport of the proton. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Neurosteroid biosynthesis in the quail brain: a review
Authors: Tsutsui Kazuyoshi , Matsunaga Masahiro , Miyabara Hitomi , Ukena Kazuyoshi
Published: August 2006

The brain traditionally has been considered to be a target site of peripheral steroid hormones. In contrast to this classical concept, new findings over the past decade have shown that the brain itself also has the capability of forming steroids de novo, the so‐called “neurosteroids”. De novo neurosteroidogenesis in the brain from cholesterol is a conserved property of vertebrates. Our studies using the quail, as an excellent animal model, have demonstrated that the avian brain possesses cytochrome P450 side‐chain cleavage enzyme (P450scc), 3β‐hydroxysteroid dehydrogenase/Δ5–Δ4‐isomerase (3β‐HSD), cytochrome P450 17α‐hydroxylase/c17,20‐lyase (P45017α,lyase), 17β‐HSD, etc., and produces pregnenolone, progesterone, 3β, 5β‐tetrahydroprogesterone, androstenedione, testosterone and estradiol from cholesterol. However, the biosynthetic pathway of neurosteroids in the avian brain from cholesterol may be still incomplete, because we recently found that the quail brain actively produces 7α‐hydroxypregnenolone, a previously undescribed avian neurosteroid. This paper summarize the advances made in our understanding of biosynthesis of neurosteroids in the avian brain. J. Exp. Zool. 305A:733–742, 2006. © 2006 Wiley‐Liss, Inc.
Structures and diverse functions of frog growth hormone‐releasing peptide (fGRP) and its related peptides (fGRP‐RPs): a review
Authors: Ukena Kazuyoshi , Koda Aya , Yamamoto Kazutoshi , Iwakoshi‐ukena Eiko , Minakata Hiroyuki , Kikuyama Sakae , Tsutsui Kazuyoshi
Published: August 2006

A new Arg–Phe–NH2 (RFamide) peptide has been discovered in the amphibian hypothalamus. The cell bodies and terminals containing this peptide were localized in the suprachiasmatic nucleus and median eminence, respectively. This peptide was further revealed to have a considerable growth hormone (GH)‐releasing activity in vitro and in vivo and hence designated as frog GH‐releasing peptide (fGRP). Molecular cloning of cDNA encoding the fGRP precursor polypeptide revealed that it encodes fGRP and its putative gene‐related peptides (fGRP‐RP‐1, ‐RP‐2, and ‐RP‐3). Subsequently, we identified these putative fGRP‐RPs as mature peptides and analyzed their hypophysiotropic activities. Only fGRP‐RP‐2 stimulated the release of GH and prolactin (PRL) in vitro and in vivo. Thus, in addition to fGRP, fGRP‐RP‐2 acts as a hypothalamic factor on the frog pituitary to stimulate the release of GH and PRL. J. Exp. Zool. 305A:815–821, 2006. © 2006 Wiley‐Liss, Inc.
Interactions of gonadotropin‐releasing hormone (GnRH) and gonadotropin‐inhibitory hormone (GnIH) in birds and mammals
Authors: Bentley George E. , Kriegsfeld Lance J. , Osugi Tomohiro , Ukena Kazuyoshi , O'brien Sara , Perfito Nicole , Moore Ignacio T. , Tsutsui Kazuyoshi , Wingfield John C.
Published: August 2006

Gonadotropin‐releasing hormone (GnRH) regulates secretion of both of the gonadotropins, luteinizing hormone (LH) and follicle‐stimulating hormone. Thus, it is a key hormone for vertebrate reproduction. GnRH was considered to be unusual among hypothalamic neuropeptides in that it appeared to have no direct antagonist, although some neurochemicals and peripheral hormones (opiates, GABA, gonadal steroids, inhibin) can modulate gonadotropin release to a degree. Five years ago, a vertebrate hypothalamic neuropeptide that inhibited pituitary gonadotropin release in a dose‐dependent manner was discovered in quail by Tsutsui et al. (2000. Biochem Biophys Res Commun 275:661–667). We now know that this inhibitory peptide, named gonadotropin‐inhibitory hormone, or GnIH, is a regulator of gonadotropin release in vitro and in vivo. Its discovery has opened the door to an entirely new line of research within the realm of reproductive biology. In our collaborative studies, we have begun to elucidate the manner in which GnIH interacts with GnRH to time release of gonadotropins and thus time reproductive activity in birds and mammals. This paper reviews the distribution of GnIH in songbirds relative to GnRHs, and our findings on its modes of action in vitro and in vivo, based on laboratory and field studies. These data are simultaneously compared with our findings in mammals, highlighting how the use of different model species within different vertebrate classes can be a useful approach to identify the conserved actions of this novel neuropeptide, along with its potential importance to vertebrate reproduction. J. Exp. Zool. 305A:807–814, 2006.© 2006 Wiley‐Liss, Inc.
Contribution of comparative fish studies to general endocrinology: structure and function of some osmoregulatory hormones
Authors: Takei Yoshio , Kawakoshi Akatsuki , Tsukada Takehiro , Yuge Shinya , Ogoshi Maho , Inoue Koji , Hyodo Susumu , Bannai Hideo , Miyano Satoru
Published: August 2006

Fish endocrinologists are commonly motivated to pursue their research driven by their own interests in these aquatic animals. However, the data obtained in fish studies not only satisfy their own interests but often contribute more generally to the studies of other vertebrates, including mammals. The life of fishes is characterized by the aquatic habitat, which demands many physiological adjustments distinct from the terrestrial life. Among them, body fluid regulation is of particular importance as the body fluids are exposed to media of varying salinities only across the thin respiratory epithelia of the gills. Endocrine systems play pivotal roles in the homeostatic control of body fluid balance. Judging from the habitat‐dependent control mechanisms, some osmoregulatory hormones of fish should have undergone functional and molecular evolution during the ecological transition to the terrestrial life. In fact, water‐regulating hormones such as vasopressin are essential for survival on the land, whereas ion‐regulating hormones such as natriuretic peptides, guanylins and adrenomedullins are diversified and exhibit more critical functions in aquatic species. In this short review, we introduce some examples illustrating how comparative fish studies contribute to general endocrinology by taking advantage of such differences between fishes and tetrapods. In a functional context, fish studies often afford a deeper understanding of the essential actions of a hormone across vertebrate taxa. Using the natriuretic peptide family as an example, we suggest that more functional studies on fishes will bring similar rewards of understanding. At the molecular level, recent establishment of genome databases in fishes and mammals brings clues to the evolutionary history of hormone molecules via a comparative genomic approach. Because of the functional and molecular diversification of ion‐regulating hormones in fishes, this approach sometimes leads to the discovery of new hormones in tetrapods as exemplified by adrenomedullin 2. J. Exp. Zool. 305A:787–798, 2006. © 2006 Wiley‐Liss, Inc.
The stanniocalcin family of proteins
Authors: Wagner Graham F. , Dimattia Gabriel E.
Published: August 2006

Stannniocalcin (STC) is a polypeptide hormone that was originally identified in bony fishes as a systemic regulator of mineral metabolism, and is best known for its regulatory effects on calcium/phosphate transport by the gills, gut and kidneys. The mammalian homolog to fish STC was discovered in 1995 and has resulted in progressively growing interest ever since as to its possible role in humans. Moreover, new discoveries in the mammalian STC field are resulting in significant reappraisals as to its role in fishes. Perhaps the most significant of these has been the discovery of a second gene encoding stanniocalcin‐related protein, or STC‐2, first in mammals and subsequently in fish. This review covers the comparative endocrinology of the STCs in fishes and mammals from the perspectives of structure, function and regulation. It then delves into some of the newer aspects of STC‐1/STC‐2 biology that have been uncovered using both classical and transgenic approaches. Of these, one of the most intriguing discoveries relates to the receptor‐mediated sequestration of STC by target cell organelles. The functions of other newly discovered mammalian and fish STC variants are also discussed, as is the recent discovery of STC‐related homologs in invertebrates. Based on our current state of knowledge, it is apparent that STC has an ancient lineage and that the STC family of proteins is proving to have significant roles in metabolism, reproduction and development. J. Exp. Zool. 305A:769–780, 2006. © 2006 Wiley‐Liss, Inc.
Temporal gene induction patterns in sheepshead minnows exposed to 17β‐estradiol
Authors: Knoebl Iris , Blum Jason L. , Hemmer Michael J. , Denslow Nancy D.
Published: August 2006

Gene arrays provide a powerful method to examine changes in gene expression in fish due to chemical exposures in the environment. In this study, we expanded an existing gene array for sheepshead minnows (Cyprinodon variegatus) (SHM) and used it to examine temporal changes in gene expression for male SHM exposed to 100 ng 17β‐estradiol (E2)/L for five time points between 0 and 48 hr. We found that in addition to the induction of genes involved in oocyte development (vitellogenin [VTG], zona radiata [ZRP]), other genes involved in metabolism and the inflammatory response are also affected. We identified five patterns of temporal induction in genes whose expression was modified due to E2 exposure. We validated the gene array data for the expression of VTG 1, VTG 2, ZRP 2 and ZRP 3 and found that with low levels of exogenous E2 (100 ng E2/L) exposure, ZRP expression precedes VTG expression. However, at higher concentrations of E2 (500 ng E2/L), the difference in temporal expression appears to be lost. Exposure to high levels of environmental contaminants may affect the normal ordered expression of genes required for reproduction. Gene expression profiling using arrays promises to be a valuable tool in the field of environmental toxicology. As more genes are identified for species used in toxicological testing, researchers will be better able to predict adverse effects to chemical exposures and to understand the relationships between changes in gene expression and changes in phenotype. J. Exp. Zool. 305A:707–719, 2006. © 2006 Wiley‐Liss, Inc.
Patterns and mechanisms of genome organization in the mouse
Authors: Graber Joel H. , Churchill Gary A. , Dipetrillo Keith J. , King Benjamin L. , Petkov Petko M. , Paigen Ken
Published: August 2006

The physical and functional organizations of a genome are correlated outcomes of evolution. Inbred strains of mice provide a unique opportunity for exploring these relationships, representing as they do, diverse genomes originally separated by millions of generations that were then scrambled in the laboratory and subjected to intense selection during inbreeding to homozygosity. Here we show that the resulting pattern of chromosome organization includes regional domains of functionally related elements that promote the co‐inheritance and survival of compatible sets of alleles. There are also patterns of linkage disequilibrium between domains on separate chromosomes; these are distinctly non‐random and form networks with scale‐free architecture. The strong conservation of gene order among mammals suggests that the domains and networks we find likely characterize all mammals, and possibly beyond.J. Exp. Zool. 305A:683–688, 2006. © 2006 Wiley‐Liss, Inc.
Xenobiotic detoxification in the nematode Caenorhabditis elegans
Authors: Lindblom Tim H. , Dodd Allyn K.
Published: August 2006

The nematode Caenorhabditis elegans is an important model organism for the study of such diverse aspects of animal physiology and behavior as embryonic development, chemoreception, and the genetic control of lifespan. Yet, even though the entire genome sequence of this organism was deposited into public databases several years ago, little is known about xenobiotic metabolism in C. elegans. In part, the paucity of detoxification information may be due to the plush life enjoyed by nematodes raised in the laboratory. In the wild, however, these animals experience a much greater array of chemical assaults. Living in the interstitial water of the soil, populations of C. elegans exhibit a boom and bust lifestyle characterized by prodigious predation of soil microbes punctuated by periods of dispersal as a non‐developing alternative larval stage. During the booming periods of population expansion, these animals almost indiscriminately consume everything in their environment including any number of compounds from other animals, microorganisms, plants, and xenobiotics. Several recent studies have identified many genes encoding sensors and enzymes these nematodes may use in their xeno‐coping strategies. Here, we will discuss these recent advances, as well as the efforts by our lab and others to utilize the genomic resources of the C. elegans system to elucidate this nematode's molecular defenses against toxins. J. Exp. Zool. 305A:720–730, 2006. © 2006 Wiley‐Liss, Inc.
A survivin‐mediated oncolytic adenovirus induces non‐apoptotic cell death in lung cancer cells and shows antitumoral potential in vivo
Authors: Li Binghua , Liu Xinran , Fan Junkai , Qi Rong , Bo Linan , Gu Jinfa , Qian Qijun , Qian Cheng , Liu Xinyuan
Published: August 2006

Background

Conditionally replicating adenoviruses or oncolytic adenoviruses, which can replicate selectively in tumor cells and kill them, represent an innovative class of promising cancer therapeutics. Survivin is the smallest member of the inhibitor of apoptosis (IAP) family, which is transcriptionally upregulated exclusively in most malignant tissues but not in normal tissues. It has been reported that activity of the survivin promoter is tumor‐specific, which makes the survivin promoter a good candidate to construct oncolytic viral vectors.

Methods

A luciferase reporter assay was used to determine the activity of the survivin promoter in tumor and normal cells. An oncolytic adenovirus (Ad.SP/E1A) was generated by homologous recombination. The oncolytic efficacy of Ad.SP/E1A was evaluated in cell lines and in a human lung xenograft tumor mouse model.

Results

Survivin expression was highly upregulated in tumor cells both at the protein and mRNA level. The luciferase reporter assay showed that survivin promoter activity is tumor‐specific. Ad.SP/E1A expressed E1A selectively in tumor cells and induced cytotoxicity, but not in normal cells. Moreover, in animal experiments, intratumoral administration of Ad.SP/E1A significantly suppressed the growth of xenograft tumors. Further investigation showed that Ad.SP/E1A induced cell death by an apoptosis‐independent pathway.

Conclusions

Ad.SP/E1A could be a potent therapeutic agent for cancer gene therapy. The investigation of the mechanisms of oncolytic virus‐induced cell death in this work will shed light on the construction of more powerful vectors for cancer therapy. Copyright © 2006 John Wiley & Sons, Ltd.
Reflections: The hospitalist movement a decade later
Authors: Wachter Robert M.
Published: August 2006

August 2006 marks the 10th anniversary of the publication of an article in the New England Journal of Medicine in which Lee Goldman and I coined the term hospitalist—an event that many people characterize as the start of the hospitalist movement in the United States. The present article describes the history of those early days, highlighting some of the choices the field's initial leaders made to nurture the new specialty. In retrospect, although there were many examples of fortunate serendipity, there were also several key strategic choices, including the focus on gathering research data to demonstrate the value of the field to external stakeholders; the forceful rejection of mandatory hospitalist systems, particularly those promoted by managed care organizations; and the purposeful linking of our new field to the burgeoning movements to improve quality and patient safety in hospitals. Most of all, the field's spectacular growth and successes can be attributed to the daily work of thousands of hospitalists in clinical care, education, research, and systems improvement. These individuals have given life to our theoretical notion a decade ago that a new model for inpatient care would improve the American health care system and the care of inpatients. Journal of Hospital Medicine 2006;1:248–252. © 2006 Society of Hospital Medicine.
Physician characteristics, attitudes, and use of computerized order entry
Authors: Lindenauer Peter K. , Ling David , Pekow Penelope S. , Crawford Allison , Naglieri‐Prescod Deborah , Hoople Nancy , Fitzgerald Janice , Benjamin Evan M.
Published: August 2006

BACKGROUND

Computerized physician order entry (CPOE) is a widely advocated patient safety intervention, yet little is known about its adoption by attending physicians or community hospitals.

METHODS

We calculated the order entry rates of attending physicians at 2 hospitals by measuring the number of orders entered directly and dividing this by the sum of orders entered directly and those written by hand. These findings were paired with the results of a survey that assessed attitudes concerning the impact of CPOE on personal efficiency, quality of care, and patient safety.

RESULTS

Three hundred and fifty‐six (71%) of the 502 surveys were returned by physicians, whose median order entry rate was 66%. Forty‐two percent of respondents placed at least 80% of their orders electronically (high use), 26% placed 21%‐79% of their orders electronically (intermediate use), and 32% placed 20% or less of their orders electronically (low use). Sex, years since medical school graduation, years in practice at the study institution, and use of computers in the outpatient arena were not meaningfully different among the 3 groups. However, use of the system to place orders varied by specialty, and those with intermediate or high use of the system were more likely than low users to have used CPOE during training and to be regular users of computers for personal activities. These physicians were more likely to believe that CPOE enabled orders to be placed efficiently, that directly entered orders were carried out more rapidly, and that such orders were associated with fewer errors.

CONCLUSIONS

The adoption of CPOE by attending physicians at community hospitals varies widely. In addition to purchasing systems that support physician work flow, hospitals intent on successfully implementing CPOE should emphasize the benefits in safety and quality of this new technology. Journal of Hospital Medicine 2006;1:221–230. © 2006 Society of Hospital Medicine.
Role of phosphorylation of ERK in induction and maintenance of LTP of the C‐fiber evoked field potentials in spinal dorsal horn
Authors: Xin Wen‐Jun , Gong Qing‐Juan , Xu Ji‐Tian , Yang Hong‐Wei , Zang Ying , Zhang Tong , Li Yong‐Yong , Liu Xian‐Guo
Published: August 2006

Previous works have shown that activation of extracellular signal‐regulated kinase (ERK)/cAMP response element binding protein (CREB) pathway is essential for long‐term potentiation (LTP) in hippocampus. In the present study, the role of the ERK/CREB pathway in LTP of C‐fiber evoked field potentials in spinal dorsal horn, which is relevant to pathologic pain, was investigated in adult rats. Western blotting analysis showed that the protein level of phosphorylated ERK (p‐ERK) in ipsilateral spinal dorsal horn was transiently increased after LTP induction, starting at 15 min and returning to control at 60 min after tetanic stimulation and that the protein level of p‐CREB increased at 30 min, persisting for at least 3 hr after LTP induction. Double immunofluorescence staining showed that p‐ERK and p‐CREB were only located in neurons but not in glial cells in the spinal dorsal horn after LTP induction. More importantly, we found that spinal application of PD 98059 (100 μM), a selective MEK inhibitor, at 30 min before tetanic stimulation blocked LTP induction and prevented the increase in p‐ERK and p‐CREB in spinal dorsal horn. When applied 15 min after LTP induction, PD98059 reversed established LTP. The drug, however, did not affect the spinal LTP, when applied at 30 min after LTP. Our results suggested that activation of ERK/CREB pathway in spinal dorsal neurons is necessary for induction and maintenance of long‐term potentiation of the C‐fiber evoked field potentials. © 2006 Wiley‐Liss, Inc.
Intrathecal injection of epidermal growth factor and fibroblast growth factor 2 promotes proliferation of neural precursor cells in the spinal cords of mice with mutant human SOD1 gene
Authors: Ohta Yasuyuki , Nagai Makiko , Nagata Tetsuya , Murakami Tetsuro , Nagano Isao , Narai Hisashi , Kurata Tomoko , Shiote Mito , Shoji Mikio , Abe Koji
Published: August 2006

We investigated three steps of neural precursor cell activation—proliferation, migration, and differentiation—in amyotrophic lateral sclerosis spinal cord treated with intrathecal infusion of epidermal growth factor (EGF) and fibroblast growth factor 2 (FGF2) into the lumbar spinal cord region of normal and symptomatic transgenic (Tg) mice with a mutant human Cu/Zn superoxide dismutase (SOD1) gene. We observed that 5‐bromodeoxyuridine (BrdU) + nestin double‐labeled neural precursor cells increased in the spinal cords of Tg mice compared with non‐Tg mice, with a much greater increase produced by EGF and FGF2 treatment. The number of BrdU + nestin double‐labeled cells was larger than that of BrdU + ionized calcium‐binding adapter molecule‐1 (Iba1), BrdU + glial fibrillary acidic protein (GFAP), or BrdU + highly polysialylated neural cell adhesion molecule (PSA‐NCAM) double‐labeled cells, but none expressed neuronal nuclear antigen (NeuN). On further analysis of the gray matter of Tg mice, the number of BrdU + nestin and BrdU + PSA‐NCAM double‐labeled cells increased more in the ventral horns than the dorsal horns, which was again greatly enhanced by EGF and FGF2 treatment. Because neural precursor cells reside close to the ependyma of central canal, the present study suggests that proliferation and migration of neural precursor cells to the ventral horns is greatly activated in symptomatic Tg mice and is further enhanced by EGF and FGF2 treatment and, furthermore, that the neural precursor cells preferentially differentiate into neuronal precursor cells instead of astrocytes in Tg mice with EGF and FGF2 treatment. © 2006 Wiley‐Liss, Inc.
Contributions of muscles, ligaments, and the ground‐reaction force to tibiofemoral joint loading during normal gait
Authors: Shelburne Kevin B. , Torry Michael R. , Pandy Marcus G.
Published: August 2006

The aim of this study was twofold: first, to determine which muscles and ligaments resist the adduction moment at the knee during normal walking; and second, to describe and explain the contributions of muscles, ligaments, and the ground reaction force to medial and lateral compartment loading. Muscle forces, ground reaction forces, and joint motions obtained from a dynamic optimization solution for normal walking were used as input to a three‐dimensional model of the lower limb. A static equilibrium problem was solved at each instant of the gait cycle to determine tibiofemoral joint loading at the knee. Medial compartment loading was determined mainly by the orientation of the ground reaction force. Because this force vector passed medial to the knee, it applied an adduction moment about the joint during stance. In contrast, all of the force transmitted by the lateral compartment was due to muscle and ligament action. The muscles that contributed most to support and forward propulsion during normal walking (quadriceps and gastrocnemius) also contributed most to knee stability in the frontal plane. The knee ligaments, particularly those of the posterior lateral corner, provided stability to the knee at certain periods of the stance phase, when activity of the important stabilizing muscles was low. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1983–1990, 2006
Improved assay of coenzyme Q10 from liposomes by Tween 80 solubilisation and UV spectrophotometry
Authors: Xia Shuqin , Xu Shiying
Published: August 2006

The encapsulated coenzyme Q10 (CoQ10) level is an important index in evaluating the quality of CoQ10 liposomes. This study demonstrates a simple method to release encapsulated CoQ10 from liposomal suspension using moderate amounts of the non‐ionic surfactant Tween 80 to form mixed micelles containing phospholipids, Tween 80 and CoQ10. The encapsulated CoQ10 level was detected by means of Tween 80 solubilisation and ultraviolet (UV) spectrophotometry, in which 1 mL of the reducing agent NaBH4 (7 mg mL−1) was added. The proposed method had a good linear correlation with ethanol solubilisation and reverse phase high‐performance liquid chromatography (RP‐HPLC) and with ethanol solubilisation and UV spectrophotometry over a CoQ10 concentration range of 2.5–50 µg mL−1 (R2 > 0.999). The average recovery rate of CoQ10 from blank liposomes was estimated as 99.46 ± 1.54%. The difference in results between the organic solvent extraction method and the Tween 80 solubilisation method was not statistically significant (P > 0.05). When the latter method was applied to determine the total and the encapsulated CoQ10 content quantitatively, the relative standard deviation was lower than 5%. Therefore this method has proved to be convenient, sensitive, accurate and reproducible compared with conventional RP‐HPLC analysis and UV spectrophotometry with organic solvent extraction. Copyright © 2006 Society of Chemical Industry
Ruminal degradation of mountain pastures infested by Euphorbia polygalifolia in cattle and sheep: effect of previous grazing in invaded areas
Authors: Mora Manuel J , Hervás Gonzalo , Mantecón Ángel R , Busqué Juan , Frutos Pilar
Published: August 2006

Six cows and eight ewes were distributed in four paddocks according to a factorial design, 2 species (cattle vs sheep) × 2 grazing managements (grazing in pastures invaded vs non‐invaded by Euphorbia polygalifolia), to study the ability of sheep and cattle to ruminally degrade mountain pastures containing E. polygalifolia, as well as the influence of previous grazing in invaded areas. After a period of 17 days, rumen fluids were collected and used as microbial inoculum to examine in vitro fermentation rates and ruminal parameters of infested and non‐infested pastures. Results on parameters of gas production, extent of degradation, ammonia concentration and volatile fatty acid production of infested pastures indicate a better fermentation of this substrate in sheep than in cattle. The absence of noticeable differences when the pasture without this species of spurge was incubated suggests that most variation between ruminant species can be attributed to the presence of E. polygalifolia. The positive effect of previous grazing in invaded areas on rates of gas production, extent of degradation and ammonia concentration supports the hypothesis that the ability to degrade infested pastures may be enhanced by previous consumption, probably through an adaptation of the rumen microbiota. Copyright © 2006 Society of Chemical Industry
NMR study on the structure and stability of 4‐substituted aromatic iodosyl compounds
Authors: Hiller Achim , Patt Jörg T. , Steinbach Jörg
Published: August 2006

Two 4‐substituted aromatic iodosyl compounds were investigated with regard to their solubility, stability and chromatographic behaviour. 1‐Iodosyl‐4‐methoxy‐ and 1‐iodosyl‐4‐nitro‐benzene are soluble in methanol and provide acceptable 1H and 13C NMR spectra; however, gradual oxidation of the solvent was observed. LC‐MS analyses suggest that unlike the parent substance, iodosylbenzene, which has a polymeric structure, both compounds rather exist in the monomeric form. Copyright © 2006 John Wiley & Sons, Ltd.
Vascular wall elasticity measurement by magnetic resonance imaging
Authors: Woodrum D.A. , Romano A.J. , Lerman A. , Pandya U.H. , Brosh D. , Rossman P.J. , Lerman L.O. , Ehman R.L.
Published: August 2006

The goal of this current study was to determine whether an MRI‐based elastography (MRE) method can visualize and assess propagating mechanical waves within fluid‐filled vessels and to investigate the feasibility of measuring the elastic properties of vessel walls and quantitatively assessing stenotic lesions by using MRE. The ability to measure the Young's modulus‐wall thickness product was tested using a thin‐walled latex vessel model. Also tested in vessel models was the ability to quantitate the degree of stenosis by measuring transmitted and reflected mechanical waves. This method was then applied to ex vivo porcine models and in vivo human arteries to further test its feasibility. The results provide preliminary evidence that MRE can be used to quantitatively assess the stiffness of blood vessels, and provide a non‐morphologic method to measure stenosis. With further development, it is possible that the method can be implemented in vivo. Magn Reson Med, 2006. Published 2006 Wiley‐Liss, Inc.
Temporal correlation‐based dynamic contrast‐enhanced MR imaging improves assessment of complex pulmonary circulation in congenital heart disease
Authors: Tsai Shang‐Yueh , Wu Ming‐Ting , Lin Yi‐Ru , Hsieh Kai‐Sheng , Lin Chu‐Chuan , Huang Teng‐Yi , Chung Hsiao‐Wen , Pan Jun‐Yen , Huang Yi‐Luan , Pan Huay‐Ben , Yang Chien‐Fang
Published: August 2006

A temporal correlation (TC) mapping method is proposed to help bolus chasing during dynamic contrast‐enhanced (DCE) MRI of complex pulmonary circulation (CPC) in patients with congenital heart disease. DCE‐MRI was performed on five healthy male subjects (23–24 years old) and 25 patients (nine males and 16 females, 0.25–44 years old), and TC maps were generated by performing pixel‐based computation of cross‐correlations to the pulmonary artery with a series of time shifts in all subjects. Qualitative and quantitative evaluations were performed in comparison with original DCE images. TC maps exhibited a better signal‐to‐noise ratio (SNR) by factors of 4.3 and 1.3 in the lung parenchyma, pulmonary veins, and superior artery/vein; a better intraparenchymal contrast‐to‐noise ratio (CNR) by factors of 1.5–5.4; and a significantly higher conspicuity in all regions except the pulmonary arteries when graded with a five‐point score. TC maps evaluated by two experienced clinicians significantly added relevant information (P < 0.001), and in some cases affected the final diagnosis. We conclude that TC maps facilitate bolus chasing for DCE‐MRI by reducing recirculation effects and interframe fluctuations, and hence complements morphological imaging of CPC in patients with complex congenital heart disease. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Optimal acquisition schemes for in vivo quantitative magnetization transfer MRI
Authors: Cercignani Mara , Alexander Daniel C.
Published: August 2006

This paper uses the theory of Cramer‐Rao lower bounds (CRLB) to obtain optimal acquisition schemes for in vivo quantitative magnetization transfer (MT) imaging, although the method is generally applicable to any multiparametric MRI technique. Quantitative MT fits a two‐pool model to data collected at different sampling points or settings of amplitude and offset frequency in the MT saturation pulses. Here we use simple objective functions based on the CRLB to optimize sampling strategies for multiple parameters simultaneously, and use simulated annealing to minimize these objective functions with respect to the sampling configuration. Experiments compare optimal schemes derived for quantitative MT in the human white matter (WM) at 1.5T with previously published schemes using both synthetic and human‐brain data. Results show large reductions in error of the fitted parameters with the new schemes, which greatly increases the clinical potential of in vivo quantitative MT. Since the sampling‐scheme optimization requires specific settings of the MT parameters, we also show that the optimum schemes are robust to these settings within the range of MT parameters observed in the brain. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Contrast enhanced MRI‐guided photodynamic therapy for site‐specific cancer treatment
Authors: Vaidya Anagha , Sun Yongen , Ke Tianyi , Jeong Eun‐Kee , Lu Zheng‐Rong
Published: August 2006

Photodynamic therapy (PDT) is a minimally invasive and effective approach for cancer treatment. It is potentially useful for treating tumors that are not accessible to surgery, radiation, or destructive ablations, and are resistant to chemotherapy. Efficacious treatment of interstitial tumors with PDT requires efficient delivery of photosensitizers and accurate location of tumor tissues for effective light irradiations. In this study we performed contrast‐enhanced (CE) MRI‐guided PDT with a bifunctional polymer conjugate containing both a magnetic resonance imaging (MRI) contrast agent and a photosensitizer, poly(L‐glutamic acid) (PGA)‐(Gd‐DO3A)‐mesochlorin e6 (Mce6). The efficacy of the bifunctional conjugate in cancer CE‐MRI and cancer treatment was evaluated in athymic nude mice bearing MDA‐MB‐231 human breast carcinoma xenografts, with PGA‐(Gd‐DO3A) used as a control. The polymer conjugates preferentially accumulated in the solid tumor due to the hyperpermeability of the tumor vasculature, resulting in significant tumor enhancement for accurate tumor detection and localization by MRI. Significant therapeutic response was observed for PDT with the bifunctional conjugate as compared to the control. CE‐MRI‐guided PDT with the bifunctional conjugate is effective for tumor detection and minimally invasive cancer treatment. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Relationship between point gene mutation, chromosomal abnormality, and tumour suppressor gene methylation status in colorectal adenomas
Authors: Judson H , Stewart A , Leslie A , Pratt NR , Baty DU , Steele RJC , Carey FA
Published: August 2006

Epigenetic mechanisms in carcinogenesis may have a significant role in the development of colorectal cancer. To investigate this phenomenon in early‐stage disease, promoter methylation status in the tumour suppressor genes APC, MGMT, hMLH1, P14/P14ARF, and CDKN2A/P16 was investigated in 78 colorectal adenomas. These had previously been characterized for mutations of APC, KRAS, and TP53 genes and for chromosomal abnormality by comparative genomic hybridization (CGH). APC hypermethylation was seen in 52 tumours (66.7%). APC showed either methylation or mutation in 66 lesions (84.6%), but these events were not statistically associated. MGMT methylation was detected in 39 cases (50%). Adenomas with this abnormality showed a significantly lower number of chromosomal changes by CGH (p < 0.02), confirming that DNA repair defect of this type is associated with a lower level of chromosomal instability. An hMLH1 methylation defect was seen in only one adenoma (1.3%), from a patient who had a synchronous cancer showing the same defect. Methylation of P14 (P14ARF) was seen in 31 adenomas (39.7%) and CDKN2A (P16) abnormality in 25 (32.1%). DNA methylation at two or more loci was seen in 46 tumours (59%), while 11 lesions (14.1%) showed no evidence of hypermethylation at any of the loci studied. Methylation at any or all of MGMT, P14 or P16 was significantly associated with APC methylation (p = 0.01). Those neoplasms with more than two methylated genes showed significantly fewer chromosomal abnormalities than adenomas with one or no methylated loci (p < 0.001). There was no association between specific individual chromosomal abnormalities, APC, KRAS or TP53 mutations and any pattern of methylation abnormality. We conclude that methylation abnormality is very common in pre‐invasive colorectal neoplasia, and that high level methylation is associated with low level chromosomal instability. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Synthesis and characterization of organo‐soluble fluorinated polyimides
Authors: Hariharan R , Sarojadevi M
Published: August 2006

A novel fluorinated diamine monomer with a keto group, 4‐[4‐amino‐2‐trifluoromethyl phenoxy]‐4′‐[4‐aminophenoxy]benzophenone (ATAB) was prepared by reacting dihydroxybenzophenone with 4‐chloronitrobenzene and 2‐chloro‐5‐nitrotrifluoromethylbenzene in the presence of potassium carbonate followed by catalytic reduction with palladized carbon (10%). Fluorinated polyimides IVa–e were synthesized from the diamine mentioned above via a two‐step method (thermal and chemical imidization). Polyimides IVa–e have inherent viscosities in the range 0.65–1.06 dL g−1 (thermal imidization) and 0.82–1.56 dL g−1 (chemical imidization). The polyimides prepared by chemical imidization exhibit excellent solubility. Polyimide films exhibit tensile strength, elongation and tensile modulus in the ranges 96–106 MPa, 9–13% and 1.1–1.7 GPa, respectively. The T10 values of the polyimides are in the range 540–598 °C in nitrogen and 545–586 °C in air, with more than 50–60% char yield. They have Tg values between 244 and 285 °C. The prepared polyimides show cut‐off wavelengths in the range 365–412 nm and transmittance at 450 nm in the range 80.9–94.2%. The dielectric constants of the polyimide films are in the range 3.10–3.77 at 1 kHz and 3.04–3.66 at 10 kHz, with moisture absorption of 0.14–0.40%. Copyright © 2006 Society of Chemical Industry
Applying the SAGE technique to study the effects of electromagnetic field on biological systems
Authors: Wang San Ming
Published: August 2006

Identification of genes alternatively expressed in electromagnetic field (EMF)‐exposed cells could provide direct evidence for biological effects of EMF. As there are a few indications so far for certain genes to be influenced by EMF, genome‐wide scans of the transcriptome appear to be necessary. Among the several technologies used for genome‐wide gene expression analysis, serial analysis of gene expression (SAGE) is one promising method, which seems particularly applicable for EMF research. This review provides a brief description of the features of gene expression, illustrates the basic principle of SAGE, and discusses the advantages and limitations of SAGE as well as examples of application. This information should help investigators determine if the SAGE technique is an optimal method for evaluating the biological effects of EMF.
Motion of compliant capsules on corrugated surfaces: A means of sorting by mechanical properties
Authors: Alexeev Alexander , Verberg Rolf , Balazs Anna C.
Published: August 2006

We discuss a novel method for capturing the dynamic coupling between a fluid and an elastic solid, the so‐called fluid–structure interaction. This method integrates a lattice Boltzmann model to capture the fluid dynamics with a lattice spring model to capture the micromechanics of the solid phase. We then examine the fluid‐driven motion of microcapsules, which are modeled as fluid‐filled, elastic shells, along a corrugated substrate. We show that the ability of the capsules to navigate along the surface depends critically on capsule's elastic modulus. In particular, we illustrate how this substrate can be utilized to design a device for sorting microcapsules by their mechanical properties. These results apply not only to polymeric microcapsules, but also describe the interaction between the substrate and certain biological cells (e.g., leukocytes and other cells with cytoskeletons). Hence, by isolating species of a certain stiffness, the device could be highly useful for applications in biotechnology and tissue engineering or in the quality control of fabricated microcapsules. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2667–2678, 2006
Investigation of the temperature dependence of the internal friction in PbTe crystals
Authors: Salamov B. G. , Davarashvili O. I. , Mamedov T. S. , Darsavelidze G. Sh. , Enukashvili M. I. , Akhmedzade N. D.
Published: August 2006

In this study, internal friction (IF) measurements in the temperature interval of 20–600 °C are investigated for p‐PbTe and n‐PbTe:Cr crystals with the use of a torsion pendulum at low frequencies such as 1 Hz. The corresponding processes of diffusion of oscillation energy are characterized by values of activation energy and frequency factor. We consider that relaxation processes of IF may be the result of the dislocations that slip on the different planes. The influence of chromium doping to PbTe causes the creation of additional barriers with the oscillation of dislocations and increment of cohesion forces within the nuclei of the dislocations. The latter significantly influences the increase of shear modulus from 1.3 × 104 N/m2 for pure PbTe to 3.14 × 104 N/m2 for Cr‐doped PbTe. Moreover, IF exhibits different characters in different temperature intervals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison between ab‐initio and phenomenological modeling of the exchange couplings in diluted magnetic semiconductors: the case of Zn1–xCrxTe
Authors: Bouzerar Georges , Bouzerar Richard , Kudrnovský Josef , Ziman Timothy
Published: August 2006

Using a recently developed semi‐analytical method (Self‐Consistent Local RPA or SC‐LRPA) we study the stability of the ferromagnetic phase in diluted magnetic systems where the exchange coupling between magnetic impurities are of RKKY form. A short discussion of the relevance of these calculations with respect to the ferromagnetism observed in diluted ferromagnetic materials is provided. Then, within a two step approach, we study ferromagnetism in Zn1–x Crx Te. In the first step of our study, we calculate the magnetic couplings between Mn impurities within the LDA. In the second step, we diagonalize the resulting effective Heisenberg Hamiltonian using the SC‐LRPA. We also compare, when available, our calculations with Monte Carlo simulations and experimental measurements. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical study on the influence of surface imperfections on the properties of ferroelectric thin films in first‐order ferroelectric systems
Authors: Lin Shan , Lü Tianquan , Cao Wenwu
Published: August 2006

A generalized Ginzburg–Landau–Devonshire (GLD) theory is used to study the properties of ferroelectric thin films sandwiched between two metal electrodes with a first‐order phase transition. By taking into account the effect of the imperfect surface layer and a natural boundary condition, the temperature and film‐thickness dependence of the spontaneous polarization and the dielectric susceptibility are calculated. The depolarization field makes the polarization distribution more uniform. In addition, an asymmetric hysteresis loop can be obtained due to the existence of asymmetrical imperfect surface layers. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recursive grid methods to compute value sets and Horowitz–Sidi bounds
Authors: Gutman Per‐Olof , Nordin Mattias , Cohen Bnayahu
Published: August 2006

In this paper, recursive extensions to the standard equidistant grid method are proposed whereby the gridding is adapted locally such that a prescribed distance is achieved between neighbouring points in the computed value set (template). Also presented is the Prune algorithm, which finds the outer border of a value set defined by a set of points whose nearest neighbour lies within a prescribed distance. The Prune algorithm is part of the recursive grid methods, but can also be used independently with other methods to compute value sets. As an alternative to analytical or search algorithms, a recursive grid algorithm is presented to compute Horowitz–Sidi bounds (QFT bounds, or boundaries). Isaac Horowitz's contribution to computational methods for QFT is outlined in the perspective of the presented algorithms. Copyright © 2006 John Wiley & Sons, Ltd.