bluuebunny/crossref_metadata_2025 huggingface dataset:
Ras Protein Contributes to Cerebral Vasospasm in a Canine Double-Hemorrhage Model
Authors: Yamaguchi Mitsuo , Zhou Changman , Nanda Anil , Zhang John H.
Published: May 2004

Background and Purpose—

Mitogen-activated protein kinase (MAPK) has been shown to be involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). In the present study we examined the role of Ras protein, an upstream regulator of MAPK, and the effects of the inhibitors of Ras farnesyltransferase (FTase), FTI-277 and FTase inhibitor I, on angiographic vasospasm and clinical evaluations.

Methods—

Twenty-five dogs were randomly divided into 5 groups: control, SAH, SAH+dimethyl sulfoxide, SAH+FTI-277, and SAH+FTase inhibitor I. An established canine double-hemorrhage model of SAH was used by injecting autologous arterial blood into the cisterna magna on days 0 and 2. Angiography was performed at days 0 and 7. Clinical behavior and the activation of Ras (GTP-Ras) and phosphorylated ERK1/2 of MAPK in the basilar arteries were examined.

Results—

Severe vasospasm was obtained in the SAH and SAH+dimethyl sulfoxide dogs (42.5±2.5% and 38.9±2.4%, respectively). Enhanced GTP-Ras and phosphorylated ERK1/2 were observed in the spastic basilar arteries (
P
<0.05). Inhibitors of Ras FTase decreased GTP-Ras and phosphorylated ERK1/2, attenuated angiographic vasospasm, and improved appetite and activity scores.

Conclusions—

Ras contributes to cerebral vasospasm, and inhibitors of Ras FTase may have potential in the management of cerebral vasospasm.
Is Elevated Mean Platelet Volume Associated With a Worse Outcome in Patients With Acute Ischemic Cerebrovascular Events?
Authors: Greisenegger S. , Endler G. , Hsieh K. , Tentschert S. , Mannhalter C. , Lalouschek W.
Published: May 2004

Background and Purpose—

Increased mean platelet volume (MPV), indicating higher platelet reactivity, is associated with an increased risk of myocardial infarction. Higher levels of MPV have been found in patients with acute ischemic stroke than in control subjects. Data from smaller studies regarding an association between MPV and stroke severity and outcome have been controversial. If such an association exists, MPV might help to identify patients at increased risk of a severe course of acute cerebrovascular disease.

Methods—

Within a multicenter, cross-sectional study nested in a cohort, we analyzed the relation between MPV and stroke severity as determined by the modified Rankin Scale after 1 week in 776 patients with acute ischemic stroke or transient ischemic attack. By multivariate logistic regression modeling, we determined the influence of MPV on stroke severity, adjusting for potential confounding factors.

Results—

Patients within the highest quintile of MPV had a significantly higher risk of suffering a severe stroke, defined as modified Rankin Scale score of 3 to 6, compared with patients within the lowest quintile (odds ratio=2.6; 95% confidence interval, 1.6 to 4.1;
P
<0.001). This association remained significant after adjustment for possible confounding factors (odds ratio=2.2; 95% confidence interval, 1.2 to 4.0;
P
=0.013).

Conclusions—

Our results indicate that an elevated MPV is associated with a worse outcome for acute ischemic cerebrovascular events independent of other clinical parameters.
Female Choice and Male Courtship Behaviour in the Beaugregory Damselfish
Authors: Haley  , Itzkowitz  , Smith
Published: May 2004

During courtship in the beaugregory (Stegastes leucostictus), a coral reef fish, males turn the dorsal half of their bodies from dull brown to bright yellow, and perform a series of rapid dipping movements in front of females. To look for evidence that females select males on the basis of these characteristics, we provided males with artificial breeding sites in the field, measured their reproductive success, and videotaped courtship. Reproductive success was measured by monitoring both the number and size of egg clutches present in the breeding site that was defended by the male. Both unmanipulated and experimentally induced courtship events were videotaped in separate groups of 88 (of which 32 were videotaped courting females) and 30 males, respectively. Experimental induction of courtship was done by placing a female in a clear plastic cylinder 0.5 m away from the breeding site of a territorial male; each of the 30 males received 8 different female presentations, but never more than one a day, and with a different female every time. We compared (i) the cumulative amount of eggs and number of clutches with the amount of yellow colouration and dipping rate for individual males in both the observational and experimental groups, (ii) individual variation in percentage yellow and dipping rate (for the experimental group only) with reproductive success on the same day when courtship was videotaped, and (iii) egg survivorship (ratio of final to early stage eggs) with yellow colouration and dipping rate, to see if these characteristics indicate male parental ability. Individual variation in courtship characteristics was not correlated with reproductive success on that day. In contrast, however, mean values of percentage yellow and dip rate were correlated with both the number of clutches and amount of eggs, for both the observational and experimental group of males, indicating that females preferentially spawn with males that have the brightest yellow colouration and the highest dip rate. Percentage yellow colouration was correlated with egg survival in the unmanipulated males, but not in the experimental group, while dipping rate was not correlated with egg survival in either group. We argue here that female assessment of male courtship is part of a complex process of female choice, in which females either simultaneously or sequentially examine territorial, breeding site, and male characteristics, and thereby attempt to enhance the survivorship of their offspring.
Social Play in Arabian Babblers
Authors: Zahavi Avishag , Zahavi Amotz , Pozis-Francois Orit
Published: May 2004

Social play behavior was studied in eleven groups of tame, color-ringed Arabian babblers (Turdoides squamiceps) at the Shezaf nature reserve near Hazeva in the Rift Valley in Israel. 2500 instances of play were recorded in 950 hours of observations carried out from July 1981 to June 1983. Four hours of play interactions were recorded on video-tape and were analyzed using slow-motion techniques. Babblers' play fits all the criteria for 'social play' described by Loizos (1967) and by Muller-Schwarze (1978). The most common forms of play observed were wrestling, displacement (king-of-the-hill), chases, and tug-of-war. Several play-signals were identified: crouching, rolling over, elevation of sticks, play bow, establishing eye contact and freezing briefly in the middle of play. No vocal play-signals were observed. The ontogeny of play is briefly described. Play activity diminishes with age. Dominants play less than subordinates. Babblers tend to play with individuals close to them in rank. Breeding females rarely play. There was no effect of age, dominance or gender on the type of play. When playing, dominants use play-signals more often than subordinates do. Social tension in a group inhibited play activity. Babblers play more in summer than in winter. Bouts of play tend to alternate with bouts of allopreening. Food supplementation increased both activities. Play is more demanding than allopreening, both physically and socially. It is suggested that in babblers testing the social bond is a major component in both social play and allopreening.
Symmetry Preference as a Cognitive By-Product in Starlings
Authors: Swaddle John , Clelland R. Earl , Che Judy
Published: May 2004

There has been a great deal of interest in whether animals use trait symmetry as a visual cue to mediate behavioural interactions. In bilaterally symmetric traits, small asymmetries (termed fluctuating asymmetry) appear due to increased developmental stress and/or genes for poor developmental homeostasis. Hence, researchers have hypothesized that symmetry can reveal the developmental history and, perhaps, fitness of an individual and this is why symmetry preferences have been observed. However, an additional theory suggests that symmetry could be preferred merely because it represents the average expression of bilateral traits. Animals can learn to respond to signals by generalizing (or averaging) stimulus sets. As the average expression of a trait showing fluctuating asymmetry is zero asymmetry, theory predicts that animals could develop a symmetry preference as a by-product of learning. Here, we test this prediction empirically with European starlings (Sturnus vulgaris) and show that symmetry preferences can emerge as an outcome of generalized learning processes. Our results indicate that symmetry does not initially need to be associated with fitness to be an apparent cue in behavioural interactions and that symmetry preferences observed in nature could be independent of any putative fitness relationships.
Plume Variation, Breeding Performance and Extra-Pair Copulations in the Cattle Egret
Authors: Green David , Krebs Elizabeth , Hunte Wayne
Published: May 2004

We investigate how variation in breeding plumes influences pairing patterns, extra-pair copulations and breeding performance in the colonial cattle egret (Bubulcus ibis ibis). The breeding plumes of both male and female cattle egrets varied from almost none, to lush head, back and scapular plumes. Overall, male breeding plumes were longer and darker than those of females, but we observed the full range of plume development in both sexes. Plume development was positively correlated within breeding pairs. Females may be more selective in mate choice since they only paired with males with similar or better plumes and only accepted extra-pair copulations when the male had plumes that were greater than or equal to those of their mates. Males, in contrast frequently paired with females of lower plume development, and did not target well plumed females for extra pair copulations. Females may obtain direct benefits from pairing with well plumed males since these males copulated and fed chicks at a higher rate, although this did not lead to higher fledging success in our study. Well plumed females did not have higher nest attendance, nestling attendance, feeding rates or fledging success. Nevertheless, males appeared to invest more in a breeding attempt when paired to a well plumed female by increasing copulation rates, mate attendance and nest site attendance. Breeding plumes may therefore signal both parental and genetic quality to prospective mates.
The Frequency and Timing of Courtship and Copulation in Blackbirds, Turdus Merula, Reflect Sperm Competition and Sexual Conflict
Authors: Halupka Konrad , Wysocki Dariusz
Published: May 2004

In a long-term field study we estimated the number of copulations per pair in blackbirds at 24.2 in a single reproductive cycle. Thus it seems unlikely that the only function of copulation behaviour is just to guarantee fertilization. We considered three other hypotheses which might explain frequent pair copulation: (1) as an effect of sperm competition, (2) cooperation between pair members aiming at increasing joint production of offspring; or, (3) sexual conflict resulting in female manipulation of allocation of time and energy of the male. We found no positive correlation between the copulation frequency and reproductive performance, a result that essentially falsifies the cooperation hypothesis. Only two extra-pair copulations were recorded. However, attempts at forced extra-pair copulation were very common and a high pair copulation rate might have evolved in response to sperm competition. Alternately, relatively high copulation rate in the pre-fertile stage of the reproductive cycle and female control over timing and frequency of copulation (via solicitation of copulation and/or rejection of courtship by the male) also supports the sexual conflict scenario. We suggest that our findings support the idea that the female prolongs the period of sexual activity to induce her partner to guard her (which reduces sexual coercion from other males) and to monopolise his parental effort (the male while mate guarding cannot pursue extra-pair activity or search for better mating options).
17β-Estradiol (E2) modulates cytokine and chemokine expression in human monocyte-derived dendritic cells
Authors: Bengtsson Åsa K. , Ryan Elizabeth J. , Giordano Daniela , Magaletti Dario M. , Clark Edward A.
Published: May 2004

The effects of estrogen on the immune system are still largely unknown. We have investigated the effect of 17β-estradiol (E2) on human monocyte-derived immature dendritic cells (iDCs). Short-term culture in E2 had no effect on iDC survival or the expression of cell surface markers. However, E2 treatment significantly increased the secretion of interleukin 6 (IL-6) in iDCs and also increased secretion of osteoprotegerin (OPG) by DCs. Furthermore, E2 significantly increased secretion of the inflammatory chemokines IL-8 and monocyte chemoattractant protein 1 (MCP-1) by iDCs, but not the production of the constitutive chemokines thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC). However, after E2 pretreatment the lipopolysaccharide (LPS)–induced production of MCP-1, TARC, and MDC by DCs was clearly enhanced. Moreover, mature DCs pretreated with E2 stimulated T cells better than control cells. Finally, we found that E2 provides an essential signal for migration of mature DCs toward CCL19/macrophage inflammatory protein 3β (MIP3β). In summary, E2 may affect DC regulation of T-cell and B-cell responses, as well as help to sustain inflammatory responses. This may explain, in part, the reason serum levels of estrogen correlate with the severity of certain autoimmune diseases.
Role of G protein–gated inwardly rectifying potassium channels in P2Y12 receptor–mediated platelet functional responses
Authors: Shankar Haripriya , Murugappan Swaminathan , Kim Soochong , Jin Jianguo , Ding Zhongren , Wickman Kevin , Kunapuli Satya P.
Published: May 2004

The role of the Gi-coupled platelet P2Y12 receptor in platelet function has been well established. However, the functional effector or effectors contributing directly to αIIbβ3 activation in human platelets has not been delineated. As the P2Y12 receptor has been shown to activate G protein–gated, inwardly rectifying potassium (GIRK) channels, we investigated whether GIRK channels mediate any of the functional responses of the platelet P2Y12 receptor. Western blot analysis revealed that platelets express GIRK1, GIRK2, and GIRK4. In aspirin-treated and washed human platelets, 2 structurally distinct GIRK inhibitors, SCH23390 (R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride) and U50488H (trans-(±)-3,4-dichloro-N-methyl-N-[2-(pyrrolidinyl)cyclohexyl] benzeneacetamide methanesulfonate), inhibited adenosine diphosphate (ADP)–, 2-methylthioADP (2-MeSADP)–, U46619-, and low-dose thrombin–mediated platelet aggregation. However, the GIRK channel inhibitors did not affect platelet aggregation induced by high concentrations of thrombin, AYPGKF, or convulxin. Furthermore, the GIRK channel inhibitors reversed SFLLRN-induced platelet aggregation, inhibited the P2Y12-mediated potentiation of dense granule secretion and Akt phosphorylation, and did not affect the agonist-induced Gq-mediated platelet shape change and intracellular calcium mobilization. Unlike AR-C 69931MX, a P2Y12 receptor–selective antagonist, the GIRK channel blockers did not affect the ADP-induced adenlylyl cyclase inhibition, indicating that they do not directly antagonize the P2Y12 receptor. We conclude that GIRK channels are important functional effectors of the P2Y12 receptor in human platelets.
Multiple patients with revertant mosaicism in a single Wiskott-Aldrich syndrome family
Authors: Wada Taizo , Schurman Shepherd H. , Jagadeesh G. Jayashree , Garabedian Elizabeth K. , Nelson David L. , Candotti Fabio
Published: May 2004

We previously reported on a 43-year-old patient with Wiskott-Aldrich syndrome (WAS) who experienced progressive clinical improvement and revertant T-cell mosaicism. Deletion of the disease-causing 6-bp insertion was hypothesized to have occurred by DNA polymerase slippage. We now describe 2 additional patients from the same family who also had revertant T lymphocytes that showed selective in vivo advantage. Somatic mosaicism was demonstrated on leukocytes cryopreserved in the first patient when he was 22 years old, 11 years before his death from kidney failure. The second patient is now 16 years old, has a moderate clinical phenotype, and developed revertant cells after the age of 14 years. These results support DNA polymerase slippage as a common underlying mechanism, and they indicate that T-cell mosaicism may have different clinical effects in WAS.
Synergistic effects on erythropoiesis, thrombopoiesis, and stem cell competitiveness in mice deficient in thrombopoietin and steel factor receptors
Authors: Antonchuk Jennifer , Hyland Craig D. , Hilton Douglas J. , Alexander Warren S.
Published: May 2004

The degree of redundancy between thrombopoietin (Tpo) and steel factor (SF) cytokine pathways in the regulation of hematopoiesis was investigated by generating mice lacking both c-Mpl and fully functional c-Kit receptors. Double-mutant c-Mpl–/–KitWv/Wv mice exhibited reduced viability, making up only 2% of the offspring from c-Mpl–/–KitWv/+ intercrosses. The thrombocytopenia and megakaryocytopenia characteristic of c-Mpl–/– mice was unchanged in c-Mpl–/–KitWv/Wv mice. However, the number of megakaryocytic colony forming units (CFU-Mks) was significantly reduced, particularly in the spleen. While KitWv/Wv mice, but not c-Mpl–/– mice, are anemic, the anemia was more severe in double-mutant c-Mpl–/–KitWv/Wv mice, indicating redundancy between Tpo and SF in erythropoiesis. At the primitive cell level, c-Mpl–/– and KitWv/Wv mice have similar phenotypes, including reduced progenitors, colony forming units–spleen (CFU-Ss), and repopulating activities. All of these parameters were exacerbated in double-mutant mice. c-Mpl–/–KitWv/Wv mice had 8-fold fewer clonogenic progenitor cells and at least 28-fold fewer CFU-Ss. c-Mpl–/– mice also demonstrated a reduced threshold requirement for nonmyeloablative transplant repopulation, a trait previously associated only with KitW mice, and the level of nonmyeloablative engraftment was significantly greater in c-Mpl–/–KitWv/Wv double mutants. Thus, c-Mpl–/–KitWv/Wv mice reveal nonredundant and synergistic effects of Tpo and SF on primitive hematopoietic cells.
A hierarchical order of factors in the generation of FLK1- and SCL-expressing hematopoietic and endothelial progenitors from embryonic stem cells
Authors: Park Changwon , Afrikanova Iva , Chung Yun Shin , Zhang Wen Jie , Arentson Elizabeth , Fong Guo hua , Rosendahl Alexander , Choi Kyunghee
Published: May 2004

The receptor tyrosine kinase FLK1 and the transcription factor SCL play crucial roles in the establishment of hematopoietic and endothelial cell lineages in mice. We have previously used an in vitro differentiation model of embryonic stem (ES) cells and demonstrated that hematopoietic and endothelial cells develop via sequentially generated FLK1+ and SCL+cells. To gain a better understanding of cellular and molecular events leading to hematopoietic specification, we examined factors necessary for FLK1+ and SCL+ cell induction in serum-free conditions. We demonstrate that bone morphogenetic protein (BMP) 4 was required for the generation of FLK1+ and SCL+ cells, and that vascular endothelial growth factor (VEGF) was necessary for the expansion and differentiation of SCL-expressing hematopoietic progenitors. Consistently, Flk1-deficient ES cells responded to BMP4 and generated TER119+ and CD31+ cells, but they failed to expand in response to VEGF. The Smad1/5 and map kinase pathways were activated by BMP4 and VEGF, respectively. The overexpression of SMAD6 in ES cells resulted in a reduction of FLK1+ cells. In addition, a MAP kinase kinase 1 specific inhibitor blocked the expansion of SCL+ cells in response to VEGF. Finally, VEGF mediated expansion of hematopoietic and endothelial cell progenitors was inhibited by TGFβ1, but was augmented by activin A. Our studies suggest that hematopoietic and endothelial commitment from the mesoderm occurs via BMP4-mediated signals and that expansion and/or differentiation of such progenitors is achieved by an interplay of VEGF,TGFβ1 and activin A signaling.
Control of roof plate formation by Lmx1a in the developing spinal cord
Authors: Chizhikov Victor V. , Millen Kathleen J.
Published: May 2004

Numerous studies have identified the roof plate as an embryonic signaling center critical for dorsal central nervous system patterning, but little is known about mechanisms that control its formation and its separation from clonally related neural crest cells and dI1 sensory interneurons. We demonstrate that the LIM homeodomain transcription factor, Lmx1a,mutated in the dreher mouse, acts to withdraw dorsal spinal cord progenitors from the cell cycle and simultaneously direct their differentiation into functional roof plate cells. Lmx1a cell-autonomously represses the dI1 progenitor fate, distinguishing the roof plate and dI1 interneuron programs, two major developmental programs of the dorsal neural tube. Lmx1a is not directly involved in neural crest development. We establish that Bmp signaling from epidermal ectoderm is necessary and sufficient for inducing Lmx1a and other co-factors that also regulate the extent of roof plate induction. We conclude that Lmx1a controls multiple aspects of dorsal midline patterning and is a major mediator of early Bmp signaling in the developing spinal cord.
Unique and overlapping functions of pRb and p107 in the control of proliferation and differentiation in epidermis
Authors: Ruiz Sergio , Santos Mirentxu , Segrelles Carmen , Leis Hugo , Jorcano José Luis , Berns Anton , Paramio Jesús M. , Vooijs Marc
Published: May 2004

The retinoblastoma gene product, pRb, plays a crucial role in cell cycle regulation, differentiation and inhibition of oncogenic transformation. pRb and its closely related family members p107 and p130 perform exclusive and overlapping functions during mouse development. The embryonic lethality of Rb-null animals restricts the phenotypic analysis of these mice to mid-gestation embryogenesis. We employed the Cre/loxP system to study the function of Rb in adult mouse stratified epithelium. RbF19/F19;K14cre mice displayed hyperplasia and hyperkeratosis in the epidermis with increased proliferation and aberrant expression of differentiation markers. In vitro, pRb is essential for the maintainance of the postmitotic state of terminally differentiated keratinocytes, preventing cell cycle re-entry. However, p107 compensates for the effects of Rb loss as the phenotypic abnormalities of RbF19/F19;K14cre keratinocytes in vivo and in vitro become more severe with the concurrent loss of p107 alleles. p107 alone appears to be dispensable for all these phenotypic changes, as the presence of a single Rb allele in a p107-null background rescues all these alterations. Luciferase reporter experiments indicate that these phenotypic alterations might be mediated by increased E2F activity. Our findings support a model in which pRb in conjunction with p107 plays a central role in regulating epidermal homeostasis.
Cell lineage tracing duringXenopustail regeneration
Authors: Gargioli Cesare , Slack Jonathan M. W.
Published: May 2004

The tail of the Xenopus tadpole will regenerate following amputation, and all three of the main axial structures – the spinal cord, the notochord and the segmented myotomes – are found in the regenerated tail. We have investigated the cellular origin of each of these three tissue types during regeneration.

We produced Xenopus laevis embryos transgenic for the CMV (Simian Cytomegalovirus) promoter driving GFP (Green Fluorescent Protein) ubiquitously throughout the embryo. Single tissues were then specifically labelled by making grafts at the neurula stage from transgenic donors to unlabelled hosts. When the hosts have developed to tadpoles, they carry a region of the appropriate tissue labelled with GFP. These tails were amputated through the labelled region and the distribution of labelled cells in the regenerate was followed. We also labelled myofibres using the Cre-lox method.

The results show that the spinal cord and the notochord regenerate from the same tissue type in the stump, with no labelling of other tissues. In the case of the muscle, we show that the myofibres of the regenerate arise from satellite cells and not from the pre-existing myofibres. This shows that metaplasia between differentiated cell types does not occur, and that the process of Xenopus tail regeneration is more akin to tissue renewal in mammals than to urodele tail regeneration.
Deconstructing the genesis of animal form
Authors: Hogan Brigid
Published: May 2004

Santa Fe – with its museums and galleries full of art and crafts inspired by natural forms – was the perfect setting for a Keystone conference on vertebrate organogenesis in February 2004. Organized by Gail Martin and Cliff Tabin, the conference sessions were loosely subdivided into anatomical systems – `skin, hair, teeth', `pancreas, liver, gut',`skeleton', and so on. However, from the outset, common themes emerged that transcended particular organ systems and generated a sense of unity and excitement among the participants.
A Medium Wherein Molecular Diffusion Takes Place the Same as in a Liquid but Convection is Prohibited
Authors: Kaneko Masao , Gokan Norihiko , Takato Kiyomi
Published: May 2004

Polysacchride solids involving excess water were proposed as media wherein molecular diffusion takes place as in a liquid water, but convection is prohibited.
Spectroelectrochemical Determination of the Redox Potential of P700 in Spinach with an Optically Transparent Thin-layer Electrode
Authors: Nakamura Akimasa , Suzawa Tomoyuki , Watanabe Tadashi
Published: May 2004

Optimization of experimental conditions for spectroelectrochemistry with an optically transparent thin-layer electrode allowed us to determine the redox potential of spinach P700, the primary electron donor of photosystem I, to be +469 mV vs. SHE with significantly high reproducibility (±2 mV for 12 independent samples).
Novel Synthesis of Disaccharides Containing the 2-Amino-2-deoxy-β-d-glucopyranosyl Unit and l-Glycero-d-Manno- and 7-Deoxy-l-Glycero-d-Galacto-heptopyranoses
Authors: Martin Patrick , Lequart Vincent , Cecchelli Roméo , Boullanger Paul , Lafont Dominique , Banoub Joseph
Published: May 2004

Stereocontrolled syntheses of immunologically relevant heptopyranose disaccharides were achieved in excellent yields by the trimethylsilyl triflate promoted glycosylation of the donor 1,3,4,6-tetra-O-acetyl-2-N-allyloxycarbonyl-2-amino-2-deoxy-β-d-glucopyranose with the adequate acceptors.
Direct Attachment of Double-stranded DNA to Gold Surface for Preparation of Nano-structured Devices
Authors: Sumaoka Jun , Pan Fenggang , Nonaka Aya , Takeuchi Osamu , Shigekawa Hidemi , Komiyama Makoto
Published: May 2004

To the 5′-ends of two complementary oligonucleotides, 5′-mercapto-5′-deoxythymidine was introduced and reacted with the surface of either gold plate or colloidal gold particle. Well-defined Au(nanoparticle)/DNA-duplex/Au(plate) composite was fabricated in self-assembled monolayer (SAM) of 11-hydroxy-1-undecanethiol. The current through this composite was measured by conductive probe atomic force microscopy (CP-AFM).
Hg2+-selective Fluorogenic Chemosensor Derived from 8-Aminoquinoline
Authors: Kim Young-Hee , Youk Jin Soo , Moon So Youn , Choe Jong-In , Chang Suk-Kyu
Published: May 2004

8-Aminoquinoline-based benzothiazole derivative 3 showed distinctive Hg2+-selective fluoroionophoric properties over other transition metal ions. The fluorescence emission at 580 nm was completely quenched upon complexation with 100 equiv. of Hg2+ ions in dioxane–H2O system (9:1, v/v) and the selectivity was found to be Hg2+ > Cu2+ > other representative transition and heavy metal ions.
Preparation of Layered Li[Ni1⁄3Mn1⁄3Co1⁄3]O2 as a Cathode for Lithium Secondary Battery by Carbonate Coprecipitation Method
Authors: Cho Tae-hyung , Park Sang-mok , Yoshio Masaki
Published: May 2004

Layered Li[Mn1⁄3Ni1⁄3Co1⁄3]O2 cathode material was synthesized by carbonate coprecipitation method. SEM observation and X-ray diffraction experiment showed that the material with spherical particle morphology was successfully synthesized by the method. The cathode material delivered 180 mAh/g as an initial discharge capacity at 0.2 mA/cm2 and showed high average capacity retention ratio of 99.85%/cycle over 40 cycles.
Novel Electron-Beam Molecular Resists with High Resolution and High Sensitivity for Nanometer Lithography
Authors: Kadota Toshiaki , Kageyama Hiroshi , Wakaya Fujio , Gamo Kenji , Shirota Yasuhiko
Published: May 2004

A novel class of chemically-amplified, electron-beam molecular resists for nanometer lithography were created. These molecular resists functioned as positive resists in the presence of an acid generator, exhibiting a high sensitivity of ≈2 μC cm−2 and enabling the fabrication of ≈25 nm line patterns.
Hydrothermal Synthesis of Zinc Oxide Crystals in Homogeneous Mixture of Carbon Dioxide, Hydrogen, and Water
Authors: Sue Kiwamu , Kimura Kazuhito , Murata Kenji , Arai Kunio
Published: May 2004

Hydrothermal synthesis of zinc oxide crystals in supercritical formic acid (FA) solutions was carried out at 400 °C. Increasing FA concentration from 0.0 to 1.0 mol·kg−1 gave hexagonal plates, hexagonal pillars, and tube-like shapes. Depending on FA concentration, relative intensity of emission spectra at around 500 nm increased from 0.53 to 1.0, peak at 388 nm shifted to 393 nm, and atomic ratio O/(O + Zn) decreased from 49 to 38%.
Formation of a Three-Dimensional (3D) Structure of Nanoparticles Using Langmuir–Blodgett Method
Authors: Zhou Xuehua , Liu Chunyan , Zhang Zhiying , Jiang Long , Li Jinru
Published: May 2004

A new approach was proposed to prepare 3D structure of nanoparticles. A kind of ordered superlattice of nanogold was created layer by layer by LB technique. The UV–vis spectra monitored its formation. The TEM images and small-angle X-ray diffraction confirmed the ordered structure.
Intercalation of Mercaptocarboxylic Acid into Layered Double Hydroxide Accompanied with Oxidation of Mercapto Group
Authors: Nakayama Hirokazu , Hirami Souichiro , Tsuhako Mitsutomo
Published: May 2004

The intercalation of mercaptocarboxylic acids into magnesium–aluminum layered double hydroxide (LDH) was accompanied with the oxidation of mercapto groups in aqueous solution as evidenced by 13C solid-state NMR and Raman scattering measurements. The layers of LDH were bridged by two carboxylic groups of the corresponding disulfide, which was formed by the oxidation of mercaptocarboxylic acids.
Structure, Synthesis, and Biological Activity of 14-Methoxy-1,2-dehydrocacalol Methyl Ether, a New Modified Furanoeremophilane Type Sesquiterpene from Trichilia cuneata
Authors: Doe Matsumi , Hirai Yoshinori , Kinoshita Takamasa , Shibata Kozo , Haraguchi Hiroyuki , Morimoto Yoshiki
Published: May 2004

A new modified furanoeremophilane type sesquiterpene, (+)-14-methoxy-1,2-dehydrocacalol methyl ether (2), isolated from Trichilia cuneata exhibited inhibitory activity for mitochondrial lipid peroxidation. The first total synthesis of (±)-2 and two related sesquiterpenes, (±)-14-hydroxycacalol methyl ether (7) and 14-methoxydehydrocacalohastine (8), has also been achieved.
9.4 T and 7.05 T Magnetic Fields Accelerate a Radical Oxidation Reaction with a Hypervalent (tert-Butylperoxy)iodane
Authors: Iba Kaori , Fukuyoshi Shu-ichi , Kusumi Takenori
Published: May 2004

Strong magnetic fields produced by NMR spectrometers (300 and 400 MHz) accelerate the radical oxidation of isochroman with a hypervalent (tert-butylperoxy)iodane.
Novel Lamellar Mesostructured Zinc Sulfide Nanofibers
Authors: Li Junping , Xu Yao , Wu Dong , Sun Yuhan
Published: May 2004

ZnS nanofibers with lamellar mesostructures were synthesized by hydrothermal reaction of Zn(Ac)2 and Na2S using neutral n-alkylamines (alkyl = C8–C16) as structure-directing template and ethylenediaminetetraacetic acid as stabilizer.
Controllable Morphology Formation of Gold Nano- and Micro-plates in Amphiphilic Block Copolymer-based Liquid Crystalline Phase
Authors: Wang Luyan , Chen Xiao , Zhan Jie , Sui Zhenming , Zhao Jikuan , Sun Zhenwen
Published: May 2004

A new and simple method is used to control formation of gold nanoparticles in lyotropic liquid crystal. Triangular or hexagonal nano- and micro-plates can be obtained in PEO–PPO–PEO-based hexagonal liquid crystals after adding a small amount of cationic surfactant, CTAB. All plates are single crystals and mostly characterized by orientation along the [-111] direction. Their sizes are even longer than 10 μm. The selective adsorption of CTAB on certain crystallographic facets is the main point of supposed mechanism.
Novel Dimerization, Alkoxylation, and Sulfidation of Olefins Catalyzed by RuCl3·nH2O
Authors: Higashimura Mitsuteru , Imamura Keita , Yokogawa Yukiko , Sakakibara Tsutomu
Published: May 2004

Novel ruthenium-catalyzed reactions that employ ruthenium trichloride n-hydrate (RuCl3·nH2O) were investigated and dimerization, alkoxylation and sulfidation of olefins were noted. Adducts of Markovnikov type and anti-Markovnikov type were obtained in a stereospecific manner and in good yield, depending on the type of olefins used as the starting materials.
Evolution of ARMA Demand in Supply Chains
Authors: Zhang Xiaolong
Published: May 2004

This paper shows that an ARMA demand generates an ARMA order history when ordering decisions are made based on an order-up-to policy. The order history preserves the autoregressive structure of the demand and transforms its moving average structure according to a simple algorithm. We apply this ARMA-in-ARMA-out property to examine the evolution of the demand signal in supply chains. Its practical implications are discussed in the context of quantifying the bullwhip effect, coordinating forecasting, and evaluating information sharing.
D-Dimer Testing for Deep Venous Thrombosis: A Metaanalysis
Authors: Heim Steven W , Schectman Joel M , Siadaty Mir S , Philbrick John T
Published: May 2004

Background: The use of D-dimer assays as a rule-out test for deep venous thrombosis (DVT) is controversial. To clarify this issue we performed a systematic review of the relevant literature.

Methods: We identified eligible studies, using MEDLINE entries from February 1995 through October 2003, supplemented by a review of bibliographies of relevant articles. Studies reporting accuracy evaluations comparing D-dimer test results with lower extremity ultrasound or venography in symptomatic patients with suspected acute DVT were selected for review. Two reviewers critically appraised each study independently according to previously established methodologic standards for diagnostic test research. Those studies judged to be of highest quality were designated Level 1.

Results: The 23 Level 1 studies reported data on 21 different D-dimer assays. There was wide variation in assay sensitivity, specificity, and negative predictive values, and major differences in methodology of reviewed studies. A multivariate analysis of assay performance, controlling for sample size, DVT prevalence, reference standard, and patient mix, found few differences among the assays in effect on test performance as measured by diagnostic odds ratio. Increasing prevalence of DVT was associated with poorer test performance (P = 0.01), whereas the choice of venography as the reference standard was associated with better test performance (P <0.005).

Conclusions: Explanations for the wide variation in assay performance include differences in biochemical and technical characteristics of the assays, heterogeneity and small size of patient groups, and bias introduced by choice of reference standards. Assay sensitivity and negative predictive value were frequently <90%, uncharacteristic of a good rule-out test. General use of D-dimer assays as a stand-alone test for the diagnosis of DVT is not supported by the literature.
Eine komponentenorientierte Vorgehensweise zur Modellierung von Websites (A Component-Oriented Methodology for Modeling Websites)
Authors: Wissen Michael
Published: May 2004

Die Entwicklung webbasierter Informationssysteme ist in ihrer Komplexität gleichbedeutend mit dem Entwurf und der Umsetzung konventioneller Software. Dennoch finden Ansätze des Software Engineering in der Entwicklungspraxis bislang keine Berücksichtigung, d. h. ein systematisches Vorgehen unter Einbeziehung von Modellierungsaspekten wird dem Entwicklungsprozess webbasierter Anwendungen nicht zugrunde gelegt. Dies hat nicht nur nachteilige Auswirkungen auf die Qualität der Anwendung, sondern führt aufgrund der hohen Änderungsdynamik webbasierter Anwendungen sowie komplexer Navigationsbeziehungen und Inhaltsstrukturen vor allem zu hohen Pflege- und Wartungsaufwänden. Der vorliegende Beitrag thematisiert den Entwicklungsprozess webbasierter Anwendungen, der in Analogie zu Ansätzen des Software Engineering in unterschiedliche Entwurfsbereiche unterteilt werden soll. Zu den einzelnen Bearbeitungsphasen werden verschiedene Entwurfsmodelle vorgestellt, die auf der Grundlage einer Informations- und Metadatenstruktur den Aufbau eines Navigations-, Sichten- und Präsentationsmodells einer Website unterstützen.
REFLECTIONS ON WOMEN'S EMPOWERMENT THROUGH LOCAL REPRESENTATION IN SOUTH KOREA
Authors: Chin Mikyung
Published: May 2004

After the introduction of local autonomy, Korean feminists advocated women's participation in local politics based on life politics and spillover effect. While life politics relies on unverified gender differences, spillover effect is invalid due to the centralized political system. Therefore, local strategy needs to be supplemented with a national strategy.
Associations Between Annual Medicare Part D Low-Income Subsidy Loss and Prescription Drug Spending and Use
Authors: Fung Vicki , Price Mary , Cheng David , Patel Tej A. , Yang Zhiyou , Hsu John , Alegria Margarita , Newhouse Joseph P.
Published: February 2024

Importance

The Medicare Part D Low Income Subsidy (LIS) program provides millions of beneficiaries with drug plan premium and cost-sharing assistance. The extent to which LIS recipients experience subsidy losses with annual redetermination cycles and the resulting associations with prescription drug affordability and use are unknown.

Objective

To examine how frequently annual LIS benefits are lost among Medicare Part D beneficiaries and how this is associated with prescription drug use and out-of-pocket costs.

Design, Setting, and Participants

In this cohort study of Medicare Part D beneficiaries from 2007 to 2018, annual changes in LIS recipients among those automatically deemed eligible (eg, due to dual eligibility for Medicare and Medicaid) and nondeemed beneficiaries who must apply for LIS benefits were analyzed using Medicare enrollment and Part D event data. Subsidy losses were classified in 4 groups: temporary losses (<1 year); extended losses (≥1 year); subsidy reductions (change to partial LIS); and disenrollment from Medicare Part D after subsidy loss. Temporary losses could more likely represent subsidy losses among eligible beneficiaries. Multinomial logit models were used to examine associations between beneficiary characteristics and subsidy loss; linear regression models were used to compare changes in prescription drug cost and use in the months after subsidy losses vs before. Analyses were conducted between November 2022 and November 2023.

Exposure

Subsidy loss at the beginning of each year among subsidy recipients in December of the prior year.

Main Outcomes and Measures

The main outcomes were out-of-pocket costs and prescription drug fills overall and for 4 classes: antidiabetes, antilipid, antidepressant, and antipsychotic drugs.

Results

In 2008, 731 070 full LIS beneficiaries (17%) were not deemed automatically eligible (39% were aged <65 years; 59% were female). Nearly all beneficiaries deemed automatically eligible (≥99%) retained the subsidy annually from 2007 to 2018, compared with 78% to 84% of nondeemed beneficiaries. Among nondeemed beneficiaries, disabled individuals younger than 65 years and racial and ethnic minority groups were more likely to have temporary subsidy losses vs none. Temporary losses were associated with an average 700% increase in out-of-pocket drug costs (+$52.72/mo [95% CI, 52.52-52.92]) and 15% reductions in prescription fills (−0.58 fills/mo [95% CI, −0.59 to −0.57]) overall. Similar changes were found for antidiabetes, antilipid, antidepressant, and antipsychotic prescription drug classes. Beneficiaries who retained their subsidy had few changes.

Conclusions and Relevance

The conclusions of this cohort study suggest that efforts to help eligible beneficiaries retain Medicare Part D subsidies could improve drug affordability, treatment adherence, and reduce disparities in medication access.
Approaching Standardization: Mechanical Material Testing of Macroscopic Two‐Photon Polymerized Specimens
Authors: Koch Thomas , Zhang Wenxin , Tran Thomas T. , Wang Yingjin , Mikitisin Adrian , Puchhammer Jakob , Greer Julia R. , Ovsianikov Aleksandr , Chalupa‐Gantner Franziska , Lunzer Markus
Published: February 2024

Two‐photon polymerization (2PP) is becoming increasingly established as additive manufacturing technology for microfabrication due to its high‐resolution and the feasibility of generating complex parts. Until now, the high resolution of 2PP is also its bottleneck, as it limited throughput and therefore restricted the application to the production of microparts. Thus, mechanical properties of 2PP materials can only be characterized using nonstandardized specialized microtesting methods. Due to recent advances in 2PP technology, it is now possible to produce parts in the size of several millimeters to even centimeters, finally permitting the fabrication of macrosized testing specimens. Besides suitable hardware systems, 2PP materials exhibiting favorable mechanical properties that allow printing of up‐scaled parts are strongly demanded. In this work, the up‐scalability of three different photopolymers is investigated using a high‐throughput 2PP system and low numerical aperture optics. Testing specimens in the cm‐range are produced and tested with common or even standardized material testing methods available in conventionally equipped polymer testing labs. Examples of the characterization of mechanical, thermo‐mechanical, and fracture properties of 2PP processed materials are shown. Additionally, aspects such as postprocessing and aging are investigated. This lays a foundation for future expansion of the 2PP technology to broader industrial application.
Metastabilizing the Ruthenium Clusters by Interfacial Oxygen Vacancies for Boosted Water Splitting Electrocatalysis
Authors: Chen Ya , Liu Yaoda , Zhai Wenfang , Liu Hang , Sakthivel Thangavel , Guo Shengwu , Dai Zhengfei
Published: February 2024

Metal–support interaction (MSI) is witnessed as an essential manner to stabilize active metals and tune catalytic activity for heterogonous water splitting. Kinetically driving the water electrolysis (WE) appeals for a rational MSI system with the coupled electron‐donating/accepting (e‐D/A) characters for hydrogen/oxygen evolution reactions (HER/OER). However, the metal stabilization effect by MSI will in turn restrict the deblocking of e‐D/A properties and challenge the full electrocatalytic optimization. This study profiles a heterostructure featuring metastable Ru clusters on defective NiFe hydroxide (Ru/d‐NiFe LDH) support as a low‐precious (≈2 wt%) catalytic platform for efficient WE. It is indicated that the interfacial oxygen vacancies can deviate the stable Ru 4d5 orbit to a metastable Ru2+δ state, and regulate the metal d‐band center levels toward the facilitated HER/OER processes. Resultantly, the Ru/d‐NiFe LDH heterostructure attains the ultralow overpotentials at 10 mA cm−2 for Pt‐beyond alkaline HER (18 mV) and OER (220 mV) with fast kinetics and durability. The symmetrical water electrolyzer delivers a promising voltage of 1.49 V at 10 mA cm−2 in 1 m KOH and efficient seawater splitting performance. This work carries interesting opportunities in rationalizing sophisticated metal‐support electrocatalysts through metal‐site metastabilization engineering.
Misconceptions and meat: The impact of new knowledge on meat demand
Authors: Yang Ruoye , Raper Kellie Curry
Published: February 2024

Food labeling is intended to clarify information for consumers, yet sometimes labeling can be misleading. This study examines US consumer choice for labeled and unlabeled products across meat animal species in which differing regulations exist by species regarding hormone use in production and where consumer perception of hormone use by species varies. In the case of hormone use in US meat animal production, pork and poultry products labeled as being produced with no added hormones must also state that federal regulations prohibit the use of hormones in production. However, this required information is often obscured on retail labels. Results from expected utility models indicate that after consumers receive information regarding regulations and actual hormone use across species, the difference in utility and in willingness to pay for products labeled “produced with no added hormones” versus unlabeled product is lower for products where hormone use is restricted by federal regulations  [EconLit Citations: Q13, D12, Q18].
Controlling the Phase Transformation of Alumina for Enhanced Stability and Catalytic Properties
Authors: Jang Sejin , Gun Oh Dong , Kim Haneul , Hyun Kim Kwang , Khivantsev Konstantin , Kovarik Libor , Hun Kwak Ja
Published: February 2024

Current transition alumina catalysts require the presence of significant amounts of toxic, environmentally deleterious dopants for their stabilization. Herein, we report a simple and novel strategy to engineer transition aluminas to withstand aging temperatures up to 1200 °C without inducing the transformation to low‐surface‐area α‐Al2O3 and without requiring dopants. By judiciously optimizing the abundance of dominant facets and the interparticle distance, we can control the temperature of the phase transformation from θ‐Al2O3 to α‐Al2O3 and the specific surface sites on the latter. These specific surface sites provide favorable interactions with supported metal catalysts, leading to improved metal dispersion and greatly enhanced catalytic activity for hydrocarbon oxidation. The results presented herein not only provide molecular‐level insights into the critical factors causing deactivation and phase transformation of aluminas but also pave the way for the development of catalysts with improved activity for catalytic hydrocarbon oxidation.