bluuebunny/crossref_metadata_2025 huggingface dataset:
Uneven distribution of nucleoside transporters and intracellular enzymatic degradation prevent transport of intact [14C] adenosine across the sheep choroid plexus epithelium as a monolayer in primary culture
Authors: Redzic Zoran B , Isakovic Aleksandra J , Misirlic Dencic Sonja T , Popadic Dusan , Segal Malcolm B
Published: April 2006

Background

Efflux transport of adenosine across the choroid plexus (CP) epithelium might contribute to the homeostasis of this neuromodulator in the extracellular fluids of the brain. The aim of this study was to explore adenosine transport across sheep CP epithelial cell monolayers in primary culture.

Methods

To explore transport of adenosine across the CP epithelium, we have developed a method for primary culture of the sheep choroid plexus epithelial cells (CPEC) on plastic permeable supports and analysed [14C] adenosine transport across this cellular layer, [14C] adenosine metabolism inside the cells, and cellular uptake of [14C] adenosine from either of the chambers. The primary cell culture consisted of an enriched epithelial cell fraction from the sheep fourth ventricle CP and was grown on laminin-precoated filter inserts.

Results and conclusion

CPEC grew as monolayers forming typical polygonal islands, reaching optical confluence on the third day after the seeding. Transepithelial electrical resistance increased over the time after seeding up to 85 ± 9 Ω cm2 at day 8, while permeability towards [14C] sucrose, a marker of paracellular diffusion, simultaneously decreased. These cells expressed some features typical of the CPEC in situ, including three nucleoside transporters at the transcript level that normally mediate adenosine transport across cellular membranes. The estimated permeability of these monolayers towards [14C] adenosine was low and the same order of magnitude as for the markers of paracellular diffusion.

However, inhibition of the intracellular enzymes, adenosine kinase and adenosine deaminase, led to a significant increase in transcellular permeability, indicating that intracellular phosphorylation into nucleotides might be a reason for the low transcellular permeability. HPLC analysis with simultaneous detection of radioactivity revealed that [14C] radioactivity which appeared in the acceptor chamber after the incubation of CPEC monolayers with [14C] adenosine in the donor chamber was mostly present as [14C] hypoxanthine, a product of adenosine metabolic degradation. Therefore, it appears that CPEC in primary cultures act as an enzymatic barrier towards adenosine. Cellular uptake studies revealed that concentrative uptake of [14C] adenosine was confined only to the side of these cells facing the upper or apical chamber, indicating uneven distribution of nucleoside transporters.
Oral mucosal melanoma: a malignant trap
Authors: Symvoulakis Emmanouil K , Kyrmizakis Dionysios E , Drivas Emmanouil I , Koutsopoulos Anastassios V , Malandrakis Stylianos G , Skoulakis Charalambos E , Bizakis John G
Published: April 2006

Oral mucosal melanomas are highly malignant tumors. The 'chameleonic' presentation of a mainly asymptomatic condition, the rarity of these lesions, the poor prognosis and the necessity of a highly specialized treatment are factors that should be seriously considered by the involved health provider. We present the case of a 75-year-old man who was referred to the Ear, Nose and Throat department. His symptoms were voice alteration and saliva drooling, progressively worsening during the last few weeks. The absence of pain was the reason for the delay of seeking medical care. The diagnosis was an oversized oral melanoma. This is an example of how the time of diagnosis and the evolution of a disease could be seriously influenced by patient's behavior. Melanomas arising from oral mucosa have poor prognosis unless they are discovered and treated early. The vigilance of the physicians is necessary to have success in this difficult task.
Conventional radiography requires a MRI-estimated bone volume loss of 20% to 30% to allow certain detection of bone erosions in rheumatoid arthritis metacarpophalangeal joints
Authors: Ejbjerg Bo Jannik , Vestergaard Aage , Jacobsen Søren , Thomsen Henrik , Østergaard Mikkel
Published: April 2006

The aim of this study was to demonstrate the ability of conventional radiography to detect bone erosions of different sizes in metacarpophalangeal (MCP) joints of rheumatoid arthritis (RA) patients using magnetic resonance imaging (MRI) as the standard reference. A 0.2 T Esaote dedicated extremity MRI unit was used to obtain axial and coronal T1-weighted gradient echo images of the dominant 2nd to 5th MCP joints of 69 RA patients. MR images were obtained and evaluated for bone erosions according to the OMERACT recommendations. Conventional radiographs of the 2nd to 5th MCP joints were obtained in posterior-anterior projection and evaluated for bone erosions. The MRI and radiography readers were blinded to each other's assessments. Grade 1 MRI erosions (1% to 10% of bone volume eroded) were detected by radiography in 20%, 4%, 7% and 13% in the 2nd, 3rd, 4th and 5th MCP joint, respectively. Corresponding results for grade 2 erosions (11% to 20% of bone volume eroded) were 42%, 10%, 60% and 24%, and for grade 3 erosions (21% to 30% of bone volume eroded) 75%, 67%, 75% and 100%. All grade 4 (and above) erosions were detected on radiographs. Conventional radiography required a MRI-estimated bone erosion volume of 20% to 30% to allow a certain detection, indicating that MRI is a better method for detection and grading of minor erosive changes in RA MCP joints.
Phylogenetic and structural analysis of centromeric DNA and kinetochore proteins
Authors: Meraldi Patrick , McAinsh Andrew D , Rheinbay Esther , Sorger Peter K
Published: April 2006

Background

Kinetochores are large multi-protein structures that assemble on centromeric DNA (CEN DNA) and mediate the binding of chromosomes to microtubules. Comprising 125 base-pairs of CEN DNA and 70 or more protein components, Saccharomyces cerevisiae kinetochores are among the best understood. In contrast, most fungal, plant and animal cells assemble kinetochores on CENs that are longer and more complex, raising the question of whether kinetochore architecture has been conserved through evolution, despite considerable divergence in CEN sequence.

Results

Using computational approaches, ranging from sequence similarity searches to hidden Markov model-based modeling, we show that organisms with CENs resembling those in S. cerevisiae (point CENs) are very closely related and that all contain a set of 11 kinetochore proteins not found in organisms with complex CENs. Conversely, organisms with complex CENs (regional CENs) contain proteins seemingly absent from point-CEN organisms. However, at least three quarters of known kinetochore proteins are present in all fungi regardless of CEN organization. At least six of these proteins have previously unidentified human orthologs. When fungi and metazoa are compared, almost all have kinetochores constructed around Spc105 and three conserved multi-protein linker complexes (MIND, COMA, and the NDC80 complex).

Conclusion

Our data suggest that critical structural features of kinetochores have been well conserved from yeast to man. Surprisingly, phylogenetic analysis reveals that human kinetochore proteins are as similar in sequence to their yeast counterparts as to presumptive Drosophila melanogaster or Caenorhabditis elegans orthologs. This finding is consistent with evidence that kinetochore proteins have evolved very rapidly relative to components of other complex cellular structures.
Functional Neuroimaging of Semantic and Episodic Musical Memory
Authors: PLATEL HERVÉ
Published: April 2006

Abstract: The distinction between episodic and semantic memory has become very popular since it was first proposed by Tulving in 1972. So far, very few neuropsychological, psychophysical, and imaging studies have related to the mnemonic aspects of music, notably on the long‐term memory features, and practically nothing is known about the functional anatomy of long‐term memory for music. Numerous functional imaging studies have shown that retrieval from semantic and episodic memory is subserved by distinct neural networks. For instance, the HERA model (hemispheric encoding/retrieval asymmetry) ascribes to the left prefrontal cortex a preferential role in the encoding process of episodic material and the recall of semantic information, while the right prefrontal cortex would preferentially operate in the recall of episodic information. However, these results were essentially obtained with verbal and visuo‐spatial material. We have done a study to determine the neural substrates underlying the semantic and episodic components of music using familiar and nonfamiliar melodic tunes. Two distinct patterns of activations were found: bilateral activation of the middle and superior frontal areas and precuneus for episodic memory, and activation of the medial and orbital frontal cortex bilaterally, left angular gyrus, and the anterior part of the left middle and superior temporal gyri for semantic memory. We discuss these findings in light of the available neuropsychological data obtained in brain‐damaged subjects and functional neuroimaging studies.
Changing the Brain through Therapy for Musicians' Hand Dystonia
Authors: CANDIA VICTOR , ROSSET‐LLOBET JAUME , ELBERT THOMAS , PASCUAL‐LEONE ALVARO
Published: April 2006

Abstract: Focal hand dystonia is a disorder in which sensory and motor anomalies emerge that appear to be grounded in maladaptive routes of cortical plasticity. Remodeling cortical networks through sensory‐motor retuning (SMR), we achieved long‐term reduction in the symptoms of focal hand dystonia. Magnetoencephalography confirmed that SMR modified the representational cortex of the fingers, whereby the representation of the affected hand was reorganized so that it resembled more the organization of the non‐affected side. Furthermore, we observed differences in abnormal tactile acuity between patients with musician's cramp and those with writer's cramp: Using two‐point finger discrimination, dystonic musicians showed perceptual asymmetry between hands, while writer's cramp patients did not. To further evaluate the occurrence of collateral disturbances in focal dystonia, we assessed the clinical histories of 101 affected musicians. An important finding from this study was that dystonic musicians who play a similar first and second instrument reported a continuous worsening of their symptoms. In addition, collateral disturbances appeared with a shorter delay when more than one instrument was played. Taken together, these studies suggest that (1) neurological dysfunction can be reversed by context‐specific training protocols, (2) specific symptomatic and etiological differences among various forms of focal hand dystonia might result from different behavioral experiences and their central representation, and (3) the spread of symptoms might be prevented by avoiding training that implies movement patterns similar to the main affected task, and by reducing the amount of task‐associated movement behavior.
That Government Man Tried to Poison All the Klallam Indians: Metanarratives of History and Colonialism on the Central Northwest Coast
Authors: Boyd Colleen E.
Published: April 2006

Stories about the past offer important clues for understanding how people articulate the role of history within different cultural contexts. Coast Salish narratives collected by John P. Harrington concerning early colonial encounters on the Olympic Peninsula reveal indigenous methods for engaging and representing the past. Telling stories about the colonial period enabled Klallam people to frame traumatic cultural ruptures on their own terms. Two brief narratives analyzed here illustrate that such stories are not raw data to be turned into “real” history by Western academics but instead are evidence of a coeval Coast Salish historiography.
Chemical Shifts in ESCA and NMR: The Case of Bridged Trichlorosilyl-Trimethylsilyl Molecules
Authors: Nagaoka Shin-ichi , Nagashima Umpei , Ohshita Joji
Published: April 2006

A detailed examination of the relationship between chemical shifts in ESCA (electron spectroscopy for chemical analysis) and NMR (nuclear magnetic resonance) is presented for two silicon sites of bridged trichlorosilyl-trimethylsilyl molecules [Cl3Si–CnHm–Si(CH3)3 (n = 0–5 and m = 0–10)]. It is shown that the ESCA chemical shift of a silicon site mainly depends on the electronic environment within a mean radius of 1.168 Å of the nucleus and the NMR chemical shift depends on the electronic environment within a radius of more than 1.875 Å.
Electrochemical Investigations of Biologically Active 1-(3-Hydroxy-2-pyridyl)-4,4,6-trimethyl-3,4-dihydropyrimidine-2[1H]-thione at Pyrolytic Graphite Electrode
Authors: Goyal Rajendra N , Sondhi Sham M , Lahoti Anand M
Published: April 2006

Electrochemical behavior of a biologically active pyridinylpyrimidine derivative, 1-(3-hydroxy-2-pyridyl)-4,4,6-trimethyl-3,4-dihydropyrimidine-2[1H]-thione (1) has been investigated in aqueous phosphate buffers (1.9–10.6) at a pyrolytic graphite electrode (PGE). The oxidation occurred in a single well-defined oxidation peak, Ia, in the pH range 1.9–10.6. In the pH range 4.9–10.6, a reduction peak, IIc, was noticed in the reverse sweep that formed a quasi-reversible couple with peak IIa observed in the subsequent sweep towards positive potentials. The effect of concentration and sweep rate on peak potential and peak current of peak Ia established adsorption of 1 at the surface of PGE. Controlled potential coulometry experiments revealed the 5e− oxidation of 1 in acidic solution and 7e− oxidation in a neutral solution by an EC mechanism. UV–vis spectral and kinetic studies suggested formation of different intermediates in acidic and neutral media. The major product of oxidation at pH 2.7 was characterized as 2,2,4-trimethyl-2H-9-oxa-10-thia-1,4a,5-triazaphenanthrene 10,10-dioxide (6). At physiological pH 7.1, 1-(2,5-dioxo-6-pyridyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol (7a) and 1-(3,6-dioxo-3,6-dihydro-2-pyridyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-sulfonic acid (10) were identified as the oxidation products by GC-MS. A mechanism for the electrooxidation of 1 at PGE has also been suggested.
Synthesis of a Tetracopper Assembly Complex Comprised of One Macrocyclic Dinuclear Copper Unit and Two Mononuclear Copper Units: Intramolecular Electron Transfer Relevant to Multicopper Oxidase
Authors: Suetsugu Yuko , Mitsuka Yuko , Miyasato Yuji , Ohba Masaaki , Okawa Hisashi
Published: April 2006

The dinuclear copper(II) complex [Cu2(L1)](ClO4)2·CH3OH·2H2O (1) of a macrocyclic ligand H2L1, derived from the cyclic [2:2] condensation of 2,6-diformyl-4-methylphenol and 1,1,1-tri(aminomethyl)ethane, has been prepared as the type 3 copper site for modeling multicopper oxidase: 1 has two auxiliary amino groups on the macrocyclic framework. The condensation of 1 with two molecules of 2-formylpyridine through the amino groups afforded [Cu2(L2)](ClO4)2·2DMF (2). This has a Cu···Cu separation of 4.434(1) Å with no direct bridge between the two copper atoms, owing to the involvement of the auxiliary 2-pyridylmethylimino residue in coordination. The condensation of 1 with two molecules of 3-[N,N-di(2-pyridylmethyl)aminomethyl]-5-methylsalicylaldehyde in the presence of Cu(ClO4)2·6H2O afforded the tetracopper assembly complex [Cu4(L3)](ClO4)4·3H2O (3), which is comprised of a macrocyclic dinuclear Cu2(II,II) unit and two mononuclear Cu(II) units, {Cu(II)–Cu2(II,II)–Cu(II)}. Cyclic voltammograms of 3 exhibit a two-electron redox process at −0.77 V (vs Ag/Ag+) followed by two one-electron redox processes at −0.85 and −1.29 V. Coulometric studies combined with spectroscopic and EPR studies demonstrate that the redox process at −0.77 V involves the reduction of two mononuclear Cu(II) units followed by an intramolecular electron transfer from one of the reduced Cu(I) units to the dinuclear Cu2(II,II) unit: {Cu(II)–Cu2(II,II)–Cu(II)}/{Cu(I)–Cu2(II,II)–Cu(I)} → {Cu(I)–Cu2(I,II)–Cu(II)}. The resulting {Cu(I)–Cu2(I,II)–Cu(II)} species is further reduced to {Cu(I)–Cu2(I,II)–Cu(I)} at −0.85 V and to {Cu(I)–Cu2(I,I)–Cu(I)} at −1.29 V.
Dehydrogenative Nucleophilic Addition of Aliphatic Ether to Benzaldehyde Dimethyl Acetal Mediated by Ether–Boron Trifluoride (1/1) Affording 1-Alkoxy-2-alkylindenes or α,β-Unsaturated Carbonyl Compounds Specifically
Authors: Jobashi Takashi , Maeyama Katsuya , Noguchi Keiichi , Yoshida Yasuhiko , Yonezawa Noriyuki
Published: April 2006

The R2O·BF3-mediated dehydrogenative crossed aldol condensation reaction of acyclic aliphatic ethers with benzaldehyde dimethyl acetal to give specifically indene derivatives or α,β-unsaturated carbonyl compounds has been found. When the ethers have bis(β-alkylethyl) ether structures, dehydrogenative formation of enol ether equivalents followed by successive crossed aldol addition to acetal-originated electrophile and intramolecular electrophilic aromatic substitution reactions give annulation products of 1-alkoxy-2-alkylindenes. When the ether has two β- and one or more α-hydrogens, α,β-unsaturated carbonyl compounds are obtained. The structural correlation between deuterated starting materials and the obtained products, the structural requirements for ethers, and the distinct substrate specificity have revealed the reaction routes and mechanisms.
Assessing IRES activity in the HIF-1α and other cellular 5′ UTRs
Authors: Bert Andrew G. , Grépin Renaud , Vadas Mathew A. , Goodall Gregory J.
Published: April 2006

Dicistronic reporter plasmids, such as the dual luciferase-containing pR-F plasmid, have been widely used to assay cellular and viral 5′ untranslated regions (UTRs) for IRES activity. We found that the pR-F dicistronic reporter containing the 5′ UTRs from HIF-1α, VEGF, c-myc, XIAP, VEGFR-1, or Egr-1 UTRs all produce the downstream luciferase predominantly as a result of cryptic promoter activity that is activated by the SV40 enhancer elements in the plasmid. RNA transfection experiments using dicistronic or uncapped RNAs, which avoid the complication of cryptic promoter activity, indicate that the HIF-1α, VEGF, c-myc, and XIAP UTRs do have some IRES activity, although the activity was much less than that of the viral EMCV IRES. The translation of transfected monocistronic RNAs containing these cellular UTRs was greatly enhanced by the presence of a 5′ cap, raising questions as to the strength or mechanism of IRES-mediated translation in these assays.
hNaf1 is required for accumulation of human box H/ACA snoRNPs, scaRNPs, and telomerase
Authors: Hoareau-Aveilla Coralie , Bonoli Mattia , Caizergues-Ferrer Michele , Henry Yves
Published: April 2006

The human telomerase ribonucleoprotein particle (RNP) shares with box H/ACA small Cajal body (sca)RNPs and small nucleolar (sno)RNPs the proteins dyskerin, hGar1, hNhp2, and hNop10. How dyskerin, hGar1, hNhp2, and hNop10 assemble with box H/ACA scaRNAs, snoRNAs, and the RNA component of telomerase (hTR) in vivo remains unknown. In yeast, Naf1p interacts with H/ACA snoRNP proteins and may promote assembly of Cbf5p (the yeast ortholog of dyskerin) with nascent pre-snoRNAs. Here we show that the human HsQ96HR8 protein, thereafter termed hNaf1, can functionally replace endogenous Naf1p in yeast. HeLa hNaf1 associates with dyskerin and hNop10 as well as box H/ACA scaRNAs, snoRNAs, and hTR. Reduction of hNaf1 steady-state levels by RNAi significantly lowers accumulation of these components of box H/ACA scaRNP, snoRNP, and telomerase. hNaf1 is found predominantly in numerous discrete foci in the nucleoplasm and fails to accumulate within Cajal bodies or nucleoli. Altogether, these results suggest that hNaf1 intervenes in early assembly steps of human box H/ACA RNPs, including telomerase.
No Pig Atoll: Island Biogeography and the Extirpation of a Polynesian Domesticate
Authors: Giovas Christina M
Published: April 2006

The significance of the domestic pig, Sus scrofa, to prehistoric Polynesians is hinted
at by its inclusion among the species that they transported with them as they colonized
Oceania. However, archaeological data reveal a pattern of pig distribution far
more extensive in prehistory than at historic contact. Domestic mammal extirpation
is a phenomenon apparently unique to prehistoric Polynesia. Although well recognized,
the local extinction of domestic pigs in Polynesia prior to European contact
has yet to be satisfactorily explained. Earlier accounts attributed the patchy distribution
of pigs across the Island South Pacific to intentional extermination by their
Polynesian keepers. More recent approaches seek to understand the disappearance
of these animals within a biogeographic and ecological framework. Here, I test the
hypothesis that the success of pig husbandry is correlated with ecological variables
and demonstrate that the likelihood of pig extinction increases with decreasing
island size.
Embodying Okhotsk Ethnicity: Human Skeletal Remains from the Aonae Dune Site, Okushiri Island, Hokkaido
Authors: Matsumura Hirofumi , Hudson Mark J , Koshida Kenichiro , Minakawa Yoichi
Published: April 2006

This article describes human skeletal remains from the Aonae Dune site, Okushiri
Island, Hokkaido, Japan. Skeletal remains of an adult female and two subadults were excavated in 2002. Although these remains derived from Okhotsk culture contexts, analyses of cranial and tooth crown measurements demonstrated that Aonae Dune No. 1 (the adult female), Aonae Dune No. 2 (a child of about 11 years), and Aonae Dune No. 3 (a child of about 6 years) are morphologically closer to Epi-Jōmon or Jōmon and Ainu populations and significantly different from other Okhotsk samples in Hokkaido. It is argued that these three skeletons probably represent individuals from a different culture who were adopted into Okhotsk society.
Late Holocene Landscape Evolution and Land-Use Expansion in Tutuila, American Samoa
Authors: Pearl Frederic B
Published: April 2006

Archaeological excavations at the coast of A'asu, in Tutuila Island of American Samoa, exposed a depositional sequence spanning the past circa 700 years. With the period represented, sedimentation rates exceeded 10.15 cm per century in the valley floor and 16.34 cm per century along the valley margin. The occupational history may correlate with changes in climate, sea level, and coastal geomorphology. Although the evidence accords with the expected responses to the Little Climatic Optimum (circa 1050 to 690 B.P.) and Little Ice Age (circa 575 to 150 B.P.), the most plausible explanation for the A'asu case is that environmental change accompanied expansion of upland land use. Based on evidence here and elsewhere in Tutuila, it is proposed that the establishment of fortifications, monuments and permanent settlements in the uplands was part of a broader pattern of land-use expansion beginning in the fourteenth century A.D.
Type X Pottery, Morobe Province, Papua New Guinea: Petrography and Possible Micronesian Relationships
Authors: Specht Jim , Lilley Ian , Dickinson William R
Published: April 2006

Type X is one of four Post-Lapita pottery styles reported from Huon Peninsula and the Siassi Islands of Papua New Guinea. Previous petrographic work was inconclusive about its likely area of origin but indicated a possible Huon Peninsula source. Renewed analysis of a larger sample supports this conclusion and confirms the use of grog temper. This kind of temper is otherwise not recorded in the New Guinea region, and its use in the production of Type X was probably culturally driven. Comparisons between Type X and grog-tempered pottery from Palau, Yap, and Pohnpei in Micronesia lead to the suggestion that Type X probably derived from an otherwise unrecorded contact between Huon Peninsula and Palau about 1000 years ago. The article reviews other evidence for interaction between the New Guinea-Bismarck Archipelago region and various parts of Micronesia and concludes that the proposed Type X connection with Palau is but one of several prehistoric contacts between different parts of the regions. Recognition of such contacts, which could have been unintentional and on a small scale, may contribute to explaining the complex ethnolinguistic situation of Huon Peninsula.
Characterization of RNA in Saliva
Authors: Park Noh Jin , Li Yang , Yu Tianwei , Brinkman Brigitta MN , Wong David T
Published: April 2006

Background: We have previously shown that human mRNAs are present in saliva and can be used as biomarkers of oral cancer. In this study, we analyzed the integrity, sources, and stability of salivary RNA.

Methods: We measured the integrity of salivary RNA with reverse transcription followed by PCR (RT-PCR) or RT-quantitative PCR (RT-qPCR). To study RNA entry sites into the oral cavity, we used RT-PCR analysis of salivary RNA from the 3 major salivary glands, gingival crevice fluid, and desquamated oral epithelial cells. We measured stability of the salivary β-actin mRNA by RT-qPCR of salivary RNA incubated at room temperature for different periods of time. We measured RNA association with other macromolecules by filtering saliva through pores of different sizes before performing RT-qPCR. To assess RNA–macromolecule interaction, we incubated saliva with Triton X-100 for different periods of time before performing RT-qPCR.

Results: In most cases, we detected partial- to full-length salivary mRNAs and smaller amounts of middle and 3′ gene amplicons compared with the 5′. RNA was present in all oral fluids examined. Endogenous salivary β-actin mRNA degraded more slowly than exogenous β-actin mRNA, with half-lives of 12.2 and 0.4 min, respectively (P <0.001). Salivary RNA could not pass through 0.22 or 0.45 μm pores. Incubation of saliva with Triton X-100 accelerated degradation of salivary RNA.

Conclusions: Saliva harbors both full-length and partially degraded forms of mRNA. RNA enters the oral cavity from different sources, and association with macromolecules may protect salivary RNA from degradation.
How the Internet Lowers Prices: Evidence from Matched Survey and Automobile Transaction Data
Authors: Zettelmeyer Florian , Morton Fiona Scott , Silva-Risso Jorge
Published: April 2006

Although research has shown that the Internet has lowered the prices in some established industries, little is known about how use of the Internet lowers prices. The authors address this issue for the automobile retailing industry with matched survey and transaction data on 1500 car purchases in California. They show that the Internet lowers prices for two distinct reasons: First, the Internet informs consumers about dealers' invoice prices. Second, the referral process of online buying services helps consumers obtain lower prices. The combined information and referral price effects are −1.5%, or 22% of dealers' average gross vehicle profit. The authors also find that the benefits of gathering information differ by consumer type. Buyers who have a high disutility of bargaining but who have collected information on the specific car they eventually purchase pay 1.5% less than they otherwise would. In contrast, buyers who like the bargaining process do not benefit from such information.
Defection Detection: Measuring and Understanding the Predictive Accuracy of Customer Churn Models
Authors: Neslin Scott A. , Gupta Sunil , Kamakura Wagner , Lu Junxiang , Mason Charlotte H.
Published: April 2006

This article provides a descriptive analysis of how methodological factors contribute to the accuracy of customer churn predictive models. The study is based on a tournament in which both academics and practitioners downloaded data from a publicly available Web site, estimated a model, and made predictions on two validation databases. The results suggest several important findings. First, methods do matter. The differences observed in predictive accuracy across submissions could change the profitability of a churn management campaign by hundreds of thousands of dollars. Second, models have staying power. They suffer very little decrease in performance if they are used to predict churn for a database compiled three months after the calibration data. Third, researchers use a variety of modeling “approaches,” characterized by variables such as estimation technique, variable selection procedure, number of variables included, and time allocated to steps in the model-building process. The authors find important differences in performance among these approaches and discuss implications for both researchers and practitioners.
Drug screening in urine by cloned enzyme donor immunoassay (CEDIA) and kinetic interaction of microparticles in solution (KIMS): a comparative study
Authors: Schwettmann Lutz , Külpmann Wolf-Rüdiger , Vidal Christian
Published: April 2006

Two commercially available drug-screening assays were evaluated: the Roche kinetic interaction of microparticles in solution (KIMS) assay and the Microgenics cloned enzyme donor immunoassay (CEDIA). Urine samples from known drug-abuse patients were analyzed for amphetamines, barbiturates, benzodiazepines, benzoylecgonine, cannabinoids, LSD, methadone and opiates. Samples with discordant findings for the two assays were analyzed by gas chromatography/mass spectrometry (GC/MS) or gas chromatography/electron capture detection (GC/ECD). Amphetamines showed 96.0% concordant results, with two false positive findings by CEDIA, three by KIMS and a further two false negatives by KIMS. Barbiturates showed 99.4% concordant results, with one false negative by KIMS. Benzodiazepines showed 97.4% concordant results, with two false negatives by KIMS (cutoff 100μg/L, CEDIA cutoff 300 μg/L). Benzoylecgonine showed 17.8% concordant positive and 82.2% concordant negative results and no false finding by either assay. Cannabinoids showed 99.3% concordant results, with one sample negative by KIMS at a cutoff of 50μg/L and positive by CEDIA (cutoff 25μg/L). For LSD, 6.7% of findings were not in agreement. Methadone showed 97.5% concordant results, with two false positives by CEDIA, and one false positive and one false negative by KIMS. Opiates showed 96.9% concordant results, with no false KIMS results, but four false positives by CEDIA. The results indicate that the agreement of the CEDIA and KIMS results for the eight drugs is rather good (93.3–100%).
The GxGD Motif of Presenilin Contributes to Catalytic Function and Substrate Identification of γ-Secretase
Authors: Yamasaki Aya , Eimer Stefan , Okochi Masayasu , Smialowska Agata , Kaether Christoph , Baumeister Ralf , Haass Christian , Steiner Harald
Published: April 2006

γ-Secretase is a multisubunit aspartyl protease complex that catalyzes intramembrane cleavage of β-amyloid precursor protein (APP), a substrate key to Alzheimer's disease pathogenesis, and of Notch, a substrate crucial for cell differentiation. How γ-secretase recognizes and selects substrates is currently barely understood. Recent data suggest that its subunit nicastrin serves as an initial substrate receptor, which might subsequently forward substrates to the active site domain located in its catalytic subunit presenilin (PS), where an additional substrate binding site has been proposed. We now used an active site domain swapping approach of PS1 with its most distant homolog, spermatogenesis defective (SPE-4), to identify sequence determinants in this region. Strikingly, when the active site domain of PS1 was exchanged with that of SPE-4, the chimeric protein, PS1/SPE-46/7, supported APP but not Notch processing. In addition, PS1/SPE-46/7was strongly impaired inCaenorhabditis elegansNotch signalingin vivo. Mapping experiments identified a single amino acid at position x of the GxGD motif, which contains one of the two active site aspartates, to be responsible for the observed defect in Notch processing and signaling. Our data thus implicate a role of the GxGD motif in catalytic function and substrate identification of γ-secretase.
Symbolic Interaction as Music: The Esthetic Constitution of Meaning, Self, and Society
Authors: Vannini Phillip , Waskul Dennis
Published: April 2006

Analytical frameworks such as dramaturgy and narrative analysis are respectively grounded in metaphors of life as theater and life as a story. In related fashion, in this article the authors argue for the creation of another metaphor: life as music. Viewing selfhood and symbolic interaction as music sensitizes us to observe and understand an important but much too neglected dimension of social life: the esthetic. Drawing from the pragmatist philosophy of John Dewey, the authors argue that the realm of the esthetic should not be confined to museums and art galleries, for the intentional perception of beauty constitutes the very foundation of individuals' embodied experiences of their lifeworlds. From within our metaphor of life as music we conceptualize beauty as the diverse rhythms, melodies, and harmonies contributing to the constitution of both subjectivity and intersubjectivity.
The Region of Origin as a Tool of Marketing in Hungarian Food Economy
Authors: Lakner Zoltán , Szabó Erzsébet , Hajdu Istvánné
Published: April 2006

There is a constant disequilibrium between the supply and paying demand on the world market of agricultural products. Under these conditions the export prices are decreasing. Utilisation of region-of-origin effect can be an important tool for the increasing of value-added content of products. The article analyses the supply and demand side of regional products. It has been proven, that -as a consequence of multicultural character of Hungarian society - there is a wide range of regionally produced, traditional products. Parallel with income differentiation, there is an increasing tendency of willingness to pay among Hungarian consumers for differentiated products. Results of conjoint analysis highlight the fact, that the importance of region of origin and producer's goodwill much more important in formation of utility function of consumers, than it would be estimated by survey-type consumer research.
Origin-labeled Products - Food Quality and Food Safety in Bulgaria
Authors: Mishev Plamen , Valcheva Emilia
Published: April 2006

Bulgaria has complicated systems for food quality and food safety control. Responsibility for them is divided among several institutions. The control system is still overstaffed and insufficient co-ordination between its different parts prevail; the current control system does not meet the requirements of the new EU approach: traceability and transparency. In the last years the improvement of food quality and food safety systems in Bulgaria has been substantial - both from legislative and institutional point of view. In the process of accession Bulgarian legislation in this sphere already complies with EU regulation. Origin-labeled products is considered as an important element of food quality and food safety control systems. The legislation for organic farming, quality wines and alcoholic drinks is almost fully harmonised with the EU requirements. Important improvement has been made also with the adoption of ordinance for TSG.
Estonian Food Marketing and Labels - Development and Future Perspectives
Authors: Ohvril Tiiu
Published: April 2006

Estonian agri-food marketing has passed through clearly indicative phases during the transition period in the 1990s. The first period was characterised by loss of domestic market to foreign goods with long shelf-life and goods packages. Estonian retailers preferred foreign goods to domestic ones. Estonian trademarks were weak and the development was not encouraging. The sharp change occurred in the end of 90s, when Estonian food labels started to fight back onto the domestic market. Besides the producer brands Estonian quality labels for food were developed and launched. Today there are two quality labels - one of them being equally available for all producers of the EU, and another - emphasising domestic origin of the raw material.
Issues Regarding Origin Labeling of Food in Latvia
Authors: Melece Ligita
Published: April 2006

The paper presents results of studies which are connected with the establishment and development of quality trademarks (labels) of food products and of organically produced food products in Latvia. Also the place and importance of the food sector in total, and organic production in particular, is accented. The interpretation of EU quality mark is done and possibilities to obtain EU labels to Latvian food products are outlined At present there are two types of trademarks (labels) of food which are connected with the origin of product in Latvia: trademark “Quality Product”for quality food products which contain 75% of national or regional raw materials; trademark “Latvia's Eco-product”for organically produced products; and philosophical brand for food products “Growing green in Latvia”.
Electrical properties of Pt/Bi3.25La0.75Ti3O12/Pt thin film capacitors tailored by cerium doping
Authors: Singh S.K. , Ishiwara H.
Published: April 2006

Cerium-doped Bi3.25La0.75Ti3O12 (BLT) thin films were fabricated by depositing sol-gel solutions on Pt/Ti/SiO2/Si 〈100〉 substrates. The Ce-doping in BLT up to 6.7% of Ti atoms did not affect the single-phase bismuth-layered structure but small modification was observed in structural orientation, which influenced the microstructure and ferroelectric properties of BLT films. As we did not observe any structural distortion in x-ray diffraction data, it was suggested that doped Ce4+ was converted to Ce3+ during the annealing at 750 °C, and cerium ions might be substituted at Bi-site in BLT films. The small amount of Ce doping (1% of Ti atoms) enhanced the remanent polarization and reduced the coercive field by about 17% in BLT films, and these films showed fatigue-free response up to 1010 switching cycles at 300 kV/cm applied fields. Moderately Ce-doped films (1.7% of Ti atoms) also showed fatigue-free response up to 1010 switching cycles in 200 kV/cm applied field, but the polarization was found to increase with switching cycles when applied field was higher than 200 kV/cm. After Ce doping, the oxygen vacancy concentration may decrease in BLT films, and consequently, one can expect less domain pinning and higher fatigue resistance. Under the high cycling field, the high probability of field-assisted unpinning may be the main cause for the increased polarization.
Effects of Photodegradation on the Physical and Antioxidant Properties of Melanosomes Isolated from Retinal Pigment Epithelium
Authors: Zareba Mariusz , Szewczyk Grzegorz , Sarna Tadeusz , Hong Lian , Simon John D. , Henry Michele M. , Burke Janice M.
Published: April 2006

Melanosomes of the retinal pigment epithelium (RPE) are relatively long‐lived organelles that are theoretically susceptible to changes induced by exposure to visible light. Here melanosomes were isolated from porcine RPE cells and subjected to high intensity visible light to determine the effects of illumination on melanosome structure and on the content and antioxidant properties of melanin. As compared to untreated melanosomes, illuminated granules showed morphologic changes consistent with photodegradation, which included variable reductions in electron density demonstrated by transmission electron microscopy (TEM), and particle fragmentation and surface disruption revealed by scanning electron microscopy (SEM) and atomic force microscopy. Illuminated melanosomes had lower melanin content, indicated by measures of absorbance and electron spin resonance (ESR) signal intensity, and reduced ability to bind iron, shown by chemical and ESR analyses. Compared to untreated melanosomes, ESR‐spin trapping analyses further indicated that illuminated melanosomes show increased photogeneration of superoxide anion and reduced ability to inhibit the iron ion‐catalyzed free radical decomposition of hydrogen peroxide. It appears therefore that visible light irradiation can disrupt the structure of RPE melanosomes and reduce the amount and antioxidant properties of melanin. Some of these changes occur in human RPE melanosomes with aging and the results obtained here suggest that visible light irradiation is at least partly responsible. The consequence of light‐induced changes in RPE melanosomes may be a diminished capacity of melanin to help protect aged cells from oxidative damage, perhaps increasing the risk of diseases with an oxidative stress component such as age‐related macular degeneration.
Use of Mini Implants for Replacement and Immediate Loading of 2 Single-tooth Restorations: A Clinical Case Report
Authors: Siddiqui Azfar A. , Mark Sosovicka, , Mark Goetz,
Published: April 2006

Numerous long-term studies have shown that treatment with dental implants can provide edentulous patients with a more stable alternative to complete dentures and partially edentulous patients with a more conservative form of tooth replacement than conventional fixed partial dentures. Until recently, commercially available dental implants have been limited to diameters ranging from 3.0 mm to 7.0 mm. Although this range of diameters has been able to address most clinical needs, partially edentulous patients who could not accommodate a 3.0-mm-diameter implant without damaging adjacent dental structures were excluded from implant therapy. This article reports on the surgical treatment and immediate restoration of a patient who received mini implants that were 2.4 mm in diameter.
Peroxisome proliferator-activated receptor γ in human breast carcinoma: a modulator of estrogenic actions
Authors: Suzuki T , Hayashi S , Miki Y , Nakamura Y , Moriya T , Sugawara A , Ishida T , Ohuchi N , Sasano H
Published: April 2006

It has been reported that agonists of peroxisome proliferator-activated receptor γ (PPARγ) inhibit proliferation of breast carcinoma cells, but the biological significance of PPARγ remains undetermined in human breast carcinomas. Therefore, we immunolocalized PPARγ in 238 human breast carcinoma tissues. PPARγ immunoreactivity was detected in 42% of carcinomas, and was significantly associated with the status of estrogen receptor (ER) α, ERβ, progesterone receptor, retinoic X receptors, p21 or p27, and negatively correlated with histological grade or cyclooxygenase-2 status. PPARγ immunoreactivity was significantly associated with an improved clinical outcome of breast carcinoma patients by univariate analysis, and multivariate analysis demonstrated that PPARγ immunoreactivity was an independent prognostic factor for overall survival in ERα-positive patients. We then examined possible mechanisms of modulation by PPARγ on estrogenic actions in MCF-7 breast carcinoma cells. A PPARγ activator, 15-deoxy-Δ12,14- prostaglandin J2 (15d-PGJ2), significantly inhibited estrogen-responsive element-dependent transactivation by estradiol in MCF-7 cells, which was blocked by addition of a PPARγ antagonist GW9662. Subsequent study, employing a custom-made microarray focused on estrogen-responsive genes, revealed that mRNA expression was significantly regulated by estradiol in 49 genes, but this significance vanished on addition of 15d-PGJ2 in 16 out of 49 (33%) genes. These findings were confirmed by real-time PCR in 11 genes. 15d-PGJ2 significantly inhibited estrogen-mediated proliferation of MCF-7 cells, and caused accumulation of p21 and p27 protein. These results suggest that PPARγ is mainly expressed in well-differentiated and ER-positive breast carcinomas, and modulates estrogenic actions.
Government-Business Relations in the Construction of Mercosur
Authors: Gardini Gian Luca
Published: April 2006

Democratic consolidation was the top priority of re-democratized Argentina and Brazil. Regional integration was also part of this goal from two perspectives: from the outside, through a treaty that diminished the scope for political manoeuvring by the military and increased international support for the incumbent administrations, and; from within, through encouragement of a proactive role for business in integration that would give it democratic legitimacy, while, at the same time, exercising democratic practices. Argentine and Brazilian political classes expected to combine these two aspects but soon had to face business reluctance. Government-business relations in the construction of Mercosur reflected government attempts to balance the trade-off between the approaches from without and from within. Although business was largely excluded from the strategic formulation of integration, in a democratic context, governments have to accommodate societal interests. This occurred through a significant overlap between powerful business interests and the executive's plans. The achievement of integration helped consolidate democracy and the choices made by political elites drove forward the democratic process.
Evolutionary Dynamics and Long-Run Selection
Authors: Feinberg Yossi
Published: April 2006

We study the emergence and nature of long-run behavior of continuous state space dynamics that are subjected to random shocks. It is shown that the fine details of the underlying deterministic dynamics may be crucial in determining the evolution of the system. In particular, a risk dominated strategy can emerge in an evolutionary game subject to symmetric decaying perturbations.
How to Do Projects with Comparative Law - Notes of an Expedition to the Common Core
Authors: Frankenberg Günter
Published: April 2006

As a non-private-law scholar the author ventures on a journey into a territory virtually unknown to him and tells a rather sketchy story of his encounters with the indigenous and ingenious inhabitants of that territory and their work. The focus of this portrayal of the group of the Common Core Project takes place around some questions the author tries to answer: How may the unity and identity of the group be constructed? How do the group members define their adversaries of and the dangers to their project? And which goals do they proclaim to fight for? The author then takes a brief look at the tools the group uses to gather and order the data and tries to unearth what may be bones of contention.
Long-Term Perspectives on the Current Boom in Home Prices
Authors: Shiller Robert J.
Published: April 2006

Robert Shiller looks at over 100 years of data and asks the question every homeowner wants to know: what is the short-term and long-term prognosis for real estate values? The news isn't reassuring, but luckily risk markets are being developed to help people hedge or buy insurance against the risk that Shiller unveils.
Letter: The Costs to the Iraqi People May Become Costs to the United States
Authors: Foster John
Published: April 2006

The true cost of the war in Iraq must also include estimates of US expenditures after the war to defray the costs imposed upon non-combatant Iraqis.
Letter: Transfer Payments vs. Economic Costs in the Iraq War
Authors: D'Amato Anthony
Published: April 2006

How much of the costs of the Iraq war are really transfer payments?
Letter: Must Homeowners Lose Wealth When House Prices Fall?
Authors: Rasmusen Eric B.
Published: April 2006

Paradoxically, Eric Rasmusen argues that a fall in house prices might actually raise the wealth of homeowners.
Application of the DC-Ripple Reinjection Concept to Forced-Commutated Conversion
Authors: Yonghe Liu , Arrillaga Jos , Watson Neville R. , Perera Lasantha B.
Published: April 2006

A dc-ripple reinjection concept, described in the literature with reference to the line-commutated current source converter, is applied in this paper to the self-commutated current source converter. This is achieved by means of a reinjection converter fed, via a single-phase transformer, from the triple frequency ripple signal. It is shown that the three-phase bridge can be made to operate effectively at any multiple of the six-pulse number and, thus, presents an effective alternative to the use of ac and dc side filters.