bluuebunny/crossref_metadata_2025_split huggingface dataset:
DNA photonics
Authors: Lewis Frederick D. 
Published: December 2006

Abstract
Short DNA duplexes can be stabilized by the presence of organic chromophores, which serve as hairpin linkers or end-capping groups. Capped hairpins possessing one or more base pairs form stable folded structures in aqueous solution. Increasing the number of base pairs separating the two chromophores increases both the distance between the two chromophores and the dihedral angle between their electronic transition dipoles. Thus, duplex DNA can serve as a helical scaffold for the study of electronic interactions between two chromophores. Three types of electronic interaction have been investigated: (a) exciton coupling (EC) between two identical chromophores, as probed by exciton-coupled circular dichroism (EC-CD); (b) fluorescence resonance energy transfer (FRET) between a fluorescent donor and acceptor; and (c) photoinduced electron transfer (PET) between an electron donor and acceptor. EC and the efficiency of fluorescence energy transfer are dependent upon both the distance and dihedral angle separating the two chromophores. Electron transfer occurs via both single-step superexchange and bridge-mediated hopping mechanisms, neither of which displays angular dependence. The competition between these mechanisms is dependent upon both the energetics of hole injection into the base-pair bridge and the distance between the donor and acceptor chromophores, superexchange dominating at short distance and hole hopping at longer distances.
Cooperative self-assembly of cyanines on carboxymethylamylose and other anionic scaffolds as tools for fluorescence-based biochemical sensing
Authors: Whitten David G. , Achyuthan Komandoor E. , Lopez Gabriel P. , Kim Oh-Kil 
Published: December 2006

Abstract
We recently found that certain cyanines form tight complexes with carboxymethylamylose (CMA) in aqueous solutions and that in these complexes the cyanine exists as a strongly fluorescent and stable J-aggregate. Cyanine dyes are characterized by their ability to form J-aggregates showing very narrow absorption and fluorescence spectra relative to the monomer. Although they have found uses in sensing applications, the practicability has been limited in many cases due to the low quantum efficiencies for J-aggregate fluorescence. The CMA-cyanine complex is formed by a cooperative self-assembly in which both components undergo conformational changes during the association. The CMA exists as a random coil in solution prior to complex formation; helix formation is prevented due to repulsion of the charges on the carboxymethylated glucose units. The cyanine exists as a nonfluorescent monomer in the same solutions. A helical atomic force microscopy image and large induced circular dichroism (CD) spectra of the cyanine J-aggregate indicate that the self-assembly is a superhelix scaffold of CMA decorated with J-aggregates of the cyanine. Similar behavior was also observed with carboxymethylated cellulose (CMC). Enzymatic disruption of the helical structures (e.g., by the use of amylase to disrupt the structure of CMA helix) leads to the disappearance of the J-aggregate-associated fluorescence. The photophysical behavior and applications of this complex for sensing are discussed.
Bay-substituted perylene bisimides: Twisted fluorophores for supramolecular chemistry
Authors: Würthner Frank 
Published: December 2006

Abstract
Perylene bisimides bearing four aryloxy substituents in the 1,6,7,12 positions (so-called bay area) and two receptor units at the imide nitrogens are most useful fluorescent building blocks for the realization of a broad variety of supramolecular architectures. As discussed in this review, this versatility is not only due to the outstanding fluorescence properties of these dyes with quantum yields close to unity, but also a consequence of pronounced twisting of the π-system with an inversion barrier of around 60 kJ/mol (leading to atropisomerism) and conformational flexibility of aryloxy units. The latter two properties endow these dyes with high solubility even in least polar aliphatic solvents and enable the dyes to maintain a distance of >4 Å in their supramolecular assemblies. This feature particularly reduces the, otherwise often observed, fluorescence quenching in dye aggregates. Thus, bright luminescent cyclic and polymeric supramolecular architectures have become available from these dyes by hydrogen-bond and metal-ion directed self-assembly. In those cases where additional π-π-stacking interactions come into play, luminescent organogels and liquid crystals are obtained.
PTH Stimulates Bone Formation in Mice Deficient in Lrp5
Authors: Iwaniec Urszula T , Wronski Thomas J , Liu Jeff , Rivera Mercedes F , Arzaga Rosemarie R , Hansen Gwenn , Brommage Robert 
Published: December 2006

Abstract
Lrp5 deficiency decreases bone formation and results in low bone mass. This study evaluated the bone anabolic response to intermittent PTH treatment in Lrp5-deficient mice. Our results indicate that Lrp5 is not essential for the stimulatory effect of PTH on cancellous and cortical bone formation.
Introduction: Low-density lipoprotein receptor–related protein 5 (Lrp5), a co-receptor in canonical Wnt signaling, increases osteoblast proliferation, differentiation, and function. The purpose of this study was to use Lrp5-deficient mice to evaluate the potential role of this gene in mediating the bone anabolic effects of PTH.
Materials and Methods: Adult wildtype (WT, 23 male and 25 female) and Lrp5 knockout (KO, 27 male and 26 female) mice were treated subcutaneously with either vehicle or 80 μg/kg human PTH(1-34) on alternate days for 6 weeks. Femoral BMC and BMD were determined using DXA. Lumbar vertebrae were processed for quantitative bone histomorphometry. Bone architecture was evaluated by μCT. Data were analyzed using a multiway ANOVA.
Results: Cancellous and cortical bone mass were decreased with Lrp5 deficiency. Compared with WT mice, cancellous bone volume in the distal femur and the lumbar vertebra in Lrp5 KO mice was 54% and 38% lower, respectively (p &lt; 0.0001), whereas femoral cortical thickness was 11% lower in the KO mice (p &lt; 0.0001). The decrease in cancellous bone volume in the lumbar vertebrae was associated with a 45% decrease in osteoblast surface (p &lt; 0.0001) and a comparable decrease in bone formation rate (p &lt; 0.0001). Osteoclast surface, an index of bone resorption, was 24% lower in Lrp5 KO compared with WT mice (p &lt; 0.007). Treatment of mice with PTH for 6 weeks resulted in a 59% increase in osteoblast surface (p &lt; 0.0001) and a 19% increase in osteoclast surface (p = 0.053) in both genotypes, but did not augment cancellous bone volume in either genotype. Femur cortical thickness was 11% higher in PTH-treated mice in comparison with vehicle-treated mice (p &lt; 0.0001), regardless of genotype.
Conclusions: Whereas disruption of Lrp5 results in decreased bone mass because of decreased bone formation, Lrp5 does not seem to be essential for the stimulatory effects of PTH on cancellous and cortical bone formation.
Alkylation of ambident indole anion in ionic liquids
Authors: Zicmanis Andris , Vavilina Galina , Drozdova Svetlana , Mekss Peteris , Klavins Maris 
Published: December 2006

AbstractAlkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent of the presence of small amounts of protic solvents or water.
The immunoregulatory effects of edeine analogues in mice
Authors: Czajgucki Zbigniew , Zimecki Michał , Andruszkiewicz Ryszard 
Published: December 2006

AbstractThe edeines analogs were tested in several in vitro and in vivo assays using the mouse model, with edeine B (peptide W1) and cyclosporine A as reference compounds. The peptides displayed moderate, stimulatory effects on concanavalin A-induced (ConA-induced) splenocyte proliferation, whereas their effects on pokeweed mitogen-induced (PWM-induced) splenocyte proliferation were inhibitory. The peptides inhibited lipopolysacharide-induced (LPS-induced) tumor necrosis factor alpha production but had little effect on interleukin 6 production. In the model of the humoral immune response in vitro to sheep red blood cells, peptide 1 was distinctly stimulatory in the investigated concentrations (1-100 μg/ml), whereas peptides 3 and 4 only stimulated the number of antibody-forming cells at the highest concentration (100 μg/ml). In the model of the delayed type hypersensitivity in vivo to ovalbumin, the peptides were moderately suppressive (3 being the most active). The reference peptide W1 stimulated ConA-induced cell proliferation at 1–10 μg/ml but was inhibitory at 100 μg/ml. It also inhibited PWM-induced cell proliferation in a dose-dependent manner. This peptide had no effect on the humoral immune response in vitro or on cytokine production, but inhibited DTH reaction in vivo. The relationship between structure and activity, and a possible mode of action of the peptides, is discussed in this paper.
N-terminal brain natriuretic propeptide levels correlate with procalcitonin and C-reactive protein levels in septic patients
Authors: Piechota Mariusz , Banach Maciej , Irzmański Robert , Misztal Małgorzata , Rysz Jacek , Barylski Marcin , Piechota-Urbańska Magdalena , Kowalski Jan , Pawlicki Lucjan 
Published: December 2006

AbstractThe aim of this study was to find the relationship between N-terminal brain natriuretic propeptide (NT-proBNP), procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations in septic patients. This was a prospective study, performed at Medical University Hospital No. 5 in łódź. Twenty patients with sepsis and severe sepsis were included in the study. N-terminal brain natriuretic propeptide, procalcitonin and C-reactive protein concentrations, and survival were evaluated. In the whole studied group (128 measurements), the mean NT-proBNP, procalcitonin and C-reactive protein concentrations were, respectively: 140.80±84.65 pg/ml, 22.32±97.41 ng/ml, 128.51±79.05 mg/l. The correlations for the NT-proBNP level and procalcitonin and C-reactive protein levels were 0.3273 (p<0.001) and 0.4134 (p<0.001), respectively. NT-proBNP levels correlate with PCT and CRP levels in septic patients. In the survivor subgroup, the mean NT-proBNP plasma concentrations were significantly lower than in the non-survivor subgroup.
Partial reversal of transformed fusiform phenotype by overexpression of calreticulin
Authors: Opas Michal , Fadel Marc 
Published: December 2006

AbstractCalreticulin, a Ca2+-storage and chaperone protein of the ER, has also been shown to affect cell adhesiveness. To examine the effects of differential expression of calreticulin on cellular adhesiveness, we used L fibroblast cell lines stably expressing either elevated or reduced amounts of full length, ER-targeted calreticulin. Overexpression of calreticulin correlates with an increase in adhesiveness of L fibroblasts such that these transformed cells acquire epithelioid morphology and form an epithelial-cell sheet when crowded. Functionally, the “reversal” of transformed phenotype in L fibroblasts differentially overexpressing calreticulin can be accounted for by changes in levels of expression of N-cadherin and vinculin. Structurally, however, although the form and extent of cell-cell contacts in L fibroblasts overexpressing calreticulin mimicked those in normal epithelia, electron microscopical examination revealed that cell-cell junctions formed by these transformed cells bore only superficial resemblance to those of normal epithelia in culture. Our data imply that overexpression of calreticulin, while partially reverses fusiform transformed phenotype is in itself insufficient to re-establish bona fide zonulae adherens in transformed fibroblasts.
SNPs in the porcine PPARGC1a gene: Interbreed differences and their phenotypic effects
Authors: Stachowiak Monika , Szydlowski Maciej , Cieslak Jakub , Switonski Marek 
Published: December 2006

AbstractDue to its function, the peroxisome proliferative activated receptor-γ, coactivator-1α (PPARGC1A) gene is a candidate in the search for genes that may affect production traits in the pig. The purpose of this study was to screen for new SNPs in exon 8 of the porcine PPARGC1A gene and to test their possible association with production traits. Altogether 736 pigs representing five breeds Polish Landrace, n=242; Polish Large White, n=192; Hampshire, n=27; Duroc, 21; Pietrain, n=12) and synthetic line 990 (n=242) were scanned via SSCP assay. Four SNPs were found; two new ones: C/G (His338Gln) and G/A Thr359Thr), and two previously reported ones: C/A (Arg369Arg) and T/A Cys430Ser). The missense T/A and C/G SNPs demonstrated pronounced interbreed variability in terms of allele frequencies, including the exclusive presence of the C/G substitution in the Hampshire breed. The tested SNPs occurred in five putative haplotypes, and their frequency also differed substantially between breeds. The association of the SNPs with production traits was tested for G/A (Thr359Thr), C/A (Arg369Arg) and T/A (Cys430Ser) substitutions in Polish Large White, Polish Landrace and line 990. The analysis revealed only breed-specific associations. The T/A (Cys430Ser) SNP was related to the feed conversion ratio in the Polish Large White (P=0.02), and the silent G/A and C/A substitutions were respectively associated with abdominal fat in line 990 and backfat thickness in Polish Landrace (P=0.04). The combined effects of the substitutions were estimated as haplotype effects. Three significant contrasts between haplotypes were calculated, but the observed associations were again only breed-specific.
Optimizing OLED Efficacy of 2,7‐Diconjugated 9,9‐Dialkylfluorenes by Variation of Periphery Substitution and Conjugation Length
Authors: Rathnayake H. P. , Cirpan A. , Delen Z. , Lahti P. M. , Karasz F. E. 
Published: December 2006

AbstractThe photoluminescence (PL) and electroluminescence (EL) of four 2,7‐bis(phenylethenyl)fluorenes (OFPVs) and two 2,7‐diphenylfluorenes (OFPhs) are compared to evaluate effects of nonconjugating peripheral substitution and conjugation length on their EL emissions. The OFPVs exhibit very similar PL spectra with 460–480 nm emission maxima but show large variation in the organic light‐emitting diode (OLED) efficacy: from a material that does not give persistent emission in test OLEDs (9,9‐diheptyl substitution on the fluorene ring) to materials with luminance efficiencies of 0.5 cd A–1 and greater (9,9‐diethyl substitution on the fluorene ring, methoxy and methoxy/heptyloxy substituents on the phenylethenyl rings). The best OFPV in an ITO/PEDOT:PSS/(emitter)/Ca–Al (ITO: indium tin oxide; PEDOT: poly(ethylenedioxythiophene); PSS: poly(styrene sulfonate)) OLED configuration has 9,9‐diethyl substitution and terminal heptyloxy substitution (maximum luminance of 1500 cd m–2 at 12 V). Unlike the OFPVs, the neat OFPhs show not only EL at the desired blue output of ca. 400–410 nm emission maxima but also an undesired green emission component at 500–550 nm. Blending the OFPhs with poly(methyl methacrylate) eliminates the long‐wavelength component when the emitter load is 10–25 %, but the OFPh luminance efficiencies, turn‐on voltages, and maximum luminance tend to be poorer than those of the OFPVs. The deficiencies of the OFPhs appear to be attributable to thermal degradation and oxidative reactivity, although solid‐state annealing and a nonoptimal bandgap match to the OLED device configuration may also contribute.
Stone‐tool usage by Thai long‐tailed macaques (Macaca fascicularis)
Authors: Malaivijitnond Suchinda , Lekprayoon Chariya , Tandavanittj Nontivich , Panha Somsak , Cheewatham Cheewapap , Hamada Yuzuru 
Published: December 2006

AbstractIn January and March of 2005, we conducted surveys of long‐tailed macaques at Piak Nam Yai Island, Laem Son National Park (9° N 34–35′, 98° E 28′), Ranong Province, situated in southern Thailand. Two of the three troops of long‐tailed macaques found on the island were observed using axe‐shaped stones to crack rock oysters, detached gastropods (Thais tissoti, Petit, 1852), bivalves (Gafrarium divaricatum, Gmelin, 1791), and swimming crabs (Thalamita danae, Stimpson, 1858). They smashed the shells with stones that were held in either the left or right hand, while using the opposite hand to gather the oyster meat. Some monkeys used both hands to handle the stones. According to Matsuzawa's 1996 hierarchical classification of tool usage (levels 0–3), the tool usage by Thai long‐tailed macaques could be characterized as either level 1 (cracking rock oysters with stones) or level 2 (cracking drifting mollusks and crabs with stones by placing them on a rock). Our discovery of stone‐tool usage by Thai long‐tailed macaques provides a new point of reference for discussions regarding the evolution of tool usage and the material culture of primates. Am. J. Primatol. 69:1–7, 2007. © 2006 Wiley‐Liss, Inc.
Which senses play a role in nonhuman primate food selection? A comparison between squirrel monkeys and spider monkeys
Authors: Laska Matthias , Freist Pamela , Krause Stephanie 
Published: December 2006

AbstractIn order to optimize foraging efficiency and avoid toxicosis, animals must be able to detect, discriminate, and learn about the predictive signals of potential food. Primates are typically regarded as animals that rely mainly on their highly developed visual systems, and little is known about the role that the other senses may play in food selection. It was therefore the aim of the present study to assess which senses are involved in the evaluation of food by two species of New World primates: the squirrel monkey and the spider monkey. To this end, six animals per species were repeatedly presented with both familiar and novel food items, and their behavior was videotaped and analyzed. To obtain a further indication of the relative importance of visual and chemosensory cues, the animals were also presented with familiar food items that were experimentally modified in color, odor, or both color and odor. The results demonstrate that squirrel monkeys and spider monkeys use olfactory, gustatory, and tactile cues in addition to visual information to evaluate novel food, whereas they mainly inspect familiar food items visually prior to consumption. Our findings also show that in both species the use of nonvisual cues decreased rapidly with repeated presentations of novel food, suggesting a fast multimodal learning process. Further, the two species clearly differ in their relative use of nonvisual cues when evaluating novel or modified food, with spider monkeys relying more on olfactory cues than squirrel monkeys, and squirrel monkeys relying more on tactile cues compared to spider monkeys. Am. J. Primatol. 69:1–13, 2007. © 2006 Wiley‐Liss, Inc.
Age‐specific functions of Stone Handling, a solitary‐object play behavior, in Japanese Macaques (Macaca fuscata)
Authors: Nahallage Charmalie A.D. , Huffman Michael A. 
Published: December 2006

AbstractStone handling (SH) in Japanese macaques, a form of solitary‐object play, is newly acquired only by young individuals, and is the first example of a directly nonadaptive behavior that is maintained as a behavioral tradition within free‐ranging provisioned social troops. We report here the first systematic investigation of this behavior in a stable captive social troop, the Takahama troop, which is housed in an outdoor enclosure of the Primate Research Institute (PRI), Kyoto University, Japan. This study was conducted to evaluate relevant competing hypotheses regarding the function of object play (e.g., misdirected foraging behavior and motor training) to explain the proximal causes and ultimate function(s) of SH. The “misdirected foraging behavior” hypothesis can be ruled out because of the lack of a clear temporal relationship between feeding and the occurrence of SH in any age class. Age‐related differences in SH performance and behavioral patterns were observed, suggesting possible differences in the immediate cause and ultimate function between young and adults. Young individuals engaged in frequent bouts of short duration, involving locomotion and vigorous body actions throughout the day, which is typical for play by young in general. This pattern of behavior is consistent with the motor training hypothesis, which states that play occurs during the development of motor and perceptual skills and is thus potentially critical for neural and cognitive development. This practice is continued by those who acquire it at an early age, with adults engaging in significantly fewer but longer bouts that involve more stationary, complex manipulative patterns, almost exclusively in the late afternoon. We propose that for adults, at the proximate level SH is psychologically relaxing, but ultimately functions to maintain and regenerate neural pathways, and potentially helps to slow down the deterioration of cognitive function associated with advanced age in long‐lived provisioned and captive macaques. Am. J. Primatol. 69:1–15, 2007.© 2006 Wiley‐Liss, Inc.
Call diversity of wild male orangutans: a phylogenetic approach
Authors: Ross Marina Davila , Geissmann Thomas 
Published: December 2006

AbstractOver the past 20 years several studies have attempted to clarify orangutan systematics based on DNA sequences and karyological and morphological data; however, the systematic and phylogenetic relationships among orangutan taxa remain controversial. Surprisingly, few systematic studies have used data from wild‐living orangutans of exactly known provenance. Furthermore, most of these studies pooled data from huge geographic areas in their analyses, thus ignoring possibly distinct subpopulations. This study represents a new approach to orangutan systematics that uses orangutan long calls. Long calls are species‐specific vocalizations used by many nonhuman primates, and data on their acoustical and temporal structures have been used to assess the relationships among, and phylogenies of, several primate taxa. Altogether, 78 long calls from wild‐living orangutans from five populations in Borneo and five in Sumatra were included in the analyses. Aside from the chiefly paraphyletic topology of cladistic results, which neither support nor reject a Borneo‐Sumatra dichotomy, bootstrap values support three monophyletic clades (northwest Borneo, northeast‐east Borneo, and Ketambe) that corroborate geographic groups. The shortest trees and multivariate analyses provide some support for a closer relationship between Sumatran and specific Bornean demes than between particular Bornean demes themselves, indicating that conservation management should be based on orangutans from different populations rather than on just the two island‐specific groups. Am. J. Primatol. 69:1–20, 2007. © 2006 Wiley‐Liss, Inc.