bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of a Photostabilizer Having Built‐in Antioxidant Functionality and Its Utility in Obtaining Broad‐spectrum Sunscreen Formulations†
Authors: Chaudhuri Ratan K. , Lascu Zoia , Puccetti Germain , Deshpande Anant A. , Paknikar Sashikumar K. 
Published: February 2006

ABSTRACTDi‐2,2′‐diethylhexyl‐3,5‐dimethoxy‐4‐hydroxy‐benzylidenemalonate (INCI name diethylhexyl syringylidene malonate, DESM), the target photostabilizer, was synthesized in one step by condensation of 3,5‐dimethoxy‐4‐hydroxy benzaldehyde (Syringaldehyde) with di‐2,2′‐diethylhexyl malonate. Photo‐stability data in sunscreen formulations showed that DESM is photostable and improves the photostability of avobenzone significantly when compared to control (without a photostabilizer). Photostable broad‐spectrum sunscreen formulations with high SPF (>30) have been achieved by combining avobenzone, DESM and UV‐B sunscreens, such as homosalate, octisalate or other UV‐B sunscreens. It seems that (a) triplet‐state energy transfer from avobenzone to DESM and (b) scavenging of reactive species are responsible for the observed stabilization of avobenzone. In vitro study of the two formulations containing DESM clearly showed critical wavelength of well over 370 nm and can thus be categorized as broad‐spectrum sunscreens. DESM does not have any contribution to in vivo SPF; instead it boosts SPF by about 5 units in high‐SPF products. DESM was found to be an excellent singlet‐oxygen quencher, thereby reducing photodegradation of avobenzone caused by singlet oxygen. In short, the multiplicity of effects and formulation benefits seen with DESM makes it an ideal choice as a unique antioxidant photostabilizer for a variety of cosmetic products targeting young and mature skin alike.
A bioactive collagen-β tricalcium phosphate scaffold for tissue engineering
Authors: Oprita Elena , Moldovan Lucia , Craciunescu Oana , Buzgariu Wanda , Tardei Christu , Zarnescu Otilia 
Published: February 2006

AbstractCollagen-phosphate composites (COL/β-TCP) are novel materials that have the potential to be used as bone analogues. The aim of our study was to develop a porous bioactive material composed of type I collagen, the main bone protein and tricalcium phosphate, the mineral phase of natural bone, and investigate their in vitro biocompatibility in a human dermal fibroblast culture system. In order to obtain the bioactive materials, type I collagen was isolated from bovine tendon and characterized by physicochemical methods. β-TCP was obtained from calcium carbonate by thermal decomposition at 900 °C temperature. The powder was examined with X-ray diffraction. Two variants of COL/β-TCP scaffolds (P1 and P2) were prepared and examined by scanning electron microscopy. Our results revealed a microporous structure with small white aggregates of β-TCP, non-homogenous scattered in the collagen framework without any preferential orientation. The biocompatibility of the obtained scaffolds was tested by biochemical and histological methods on human fibroblast cultures. Both materials acted as good subtrates for human dermal fibroblast proliferation and migration.
Emerging concept of cancer as a stem cell disorder
Authors: Ratajczak Mariusz , Kucia Magda , Dobrowolska Hanna , Wanzeck Jens , Reca Ryan , Ratajczak Janina 
Published: February 2006

AbstractEvidence has accumulated that malignancy arises from maturation arrest of stem cells — rather than the dedifferentiation of somatic cells. To support this notion, stem cells in contrast to somatic cells are long lived cells and thus may become the subject of accumulating mutations that are crucial for the initiation/progression of cancer. More importantly they may maintain these mutations and pass them to daughter stem cells. Cancer stem cells (CSC) that derive from transformed normal stem cells (NSC) are responsible not only for tumor initiation, but also for its re-growth and metastasis. Accumulating evidence also indicates that adult tissues may contain a population of very small embryonic like (VSEL) stem cells that may give rise to some very immature tumors e.g., pediatric sarcomas. Similar molecular mechanisms operating in NSC and CSC regulate resistance to radio-chemotherapy and promote migration/metastasis. Thus, by studying the biology of NSC we can learn more about cancer.
Aggressive behavior among girls and boys during middle childhood: predictors and sequelae of trajectory group membership
Authors: Harachi Tracy W. , Fleming Charles B. , White Helene R. , Ensminger Margaret E. , Abbott Robert D. , Catalano Richard F. , Haggerty Kevin P. 
Published: February 2006

AbstractUsing longitudinal data spanning early elementary through middle school, aggression behavior trajectory groups were identified for boys and girls. Early elementary school predictors of trajectory group membership were examined as well as whether trajectory group predicted physical aggression, covert delinquency, and substance use in 9th grade. Semiparametric group modeling identified aggression behavior trajectory groups. We identified four aggression trajectory groups for both genders described as “not involved,” “low,” “moderate,” and “high.” Attention problems, family conflict, and low school commitment and attachment were predictors of membership in higher aggression groups for both boys and girls. Low family involvement and low parental education predicted membership in higher aggression groups for boys; while depression, low‐income status, and having a single parent predicted higher aggression group membership for girls. For both boys and girls, few risk predictors distinguished between the moderate and high aggression trajectories except that low school commitment and having a teen mother were significant predictors of being in the high group for girls, and low parental education and income were significant predictors of being in the high group for boys. Membership in the higher aggression trajectory groups predicted involvement in violent behaviors, covert delinquency, and substance use in 9th grade. Findings suggest that children who display an early trajectory of high levels of aggressive behavior are more likely to continue involvement in later problem behaviors. Second‐grade predictors suggest commonality of risk across genders and provide evidence of modifiable targets for preventive interventions. Aggr. Behav. 32:1–15. 2006. © 2006 Wiley‐Liss, Inc.
“We're not friends anymore! unless…”: the frequency and harmfulness of indirect, relational, and social aggression
Authors: Coyne Sarah M. , Archer John , Eslea Mike 
Published: February 2006

AbstractThe frequency of items of indirect, relational, social, verbal, and physical aggression was assessed in the school environment of 422 adolescents, using the Indirect/Social/Relational Aggression scale (ISRA), a measure that combined items from indirect, relational, and social aggression research. We also assessed the perceived harmfulness of each item. Comparing these findings with the occurrence of aggression on television, we found that adolescents were exposed to nearly 10 times more indirect, relational, and social aggression on television than they are in school. Overall, there was no sex difference in the amount of aggression reported by boys and girls. However, when examining specific items, girls reported more gossiping and boys more hitting. Girls perceived indirect, direct relational, and verbal aggression as more harmful than did boys. Limited evidence was found for a distinction between indirect, relational, and social aggression, although it was clear that they were more similar than different. Aggr. Behav. 32:1–14, 2006. © 2006 Wiley‐Liss, Inc.
Effects of physical provocations on heart rate reactivity and reactive aggression in children
Authors: Juujärvi Petri , Kaartinen Jukka , Laitinen Tomi , Vanninen Esko , Pulkkinen Lea 
Published: February 2006

AbstractThis article presents complementary data on the relationship between the intensity of offensive and defensive aggression that was investigated by means of the computerised Pulkkinen Aggression Machine (PAM) paradigm [Juujärvi et al., 2001; Aggr. Behav. 27:430–445]. The recording of the electrocardiogram was conducted in a sample of 109 children (61 boys and 48 girls) while they completed the PAM. Across the conditions of controlled aggression, the simulated attack and defence evoked a mean increase of HR by 2.7 beats per minute (bpm), but the variation between children was substantial (−10.9 to+11.4 bpm). Children who showed a strong HR increase, moderate HR increase, or HR decrease were compared on heart rate variability (HRV) and intensity of (defensive) reactive aggression. Variation of mean HR reactivity was generally related to changes in parasympathetic activity since the power of HRV changed in the high (0.15–0.40 Hz) rather than the low (0.04–0.15 Hz) frequency band. The correspondence between the intensity of offensive and defensive aggression was weakest among those children who displayed either a strong increase or a decrease of HR as compared to those children who exhibited only moderate increase of mean HR. The stronger the children displayed an increase of HR during the PAM, the lower they were rated on the teacher rating scales for depressive symptoms, social anxiety, and aggression. Together, these results suggest that the relationship between the intensity of physical provocations and reactive aggression was moderated by dispositional negative emotionality and its regulation. Aggr. Behav. 32:99–109, 2006. © 2006 Wiley‐Liss, Inc.
CFD and kinetic methods for mass transfer determination in a mesh microreactor
Authors: Abdallah Radwan , Magnico Pierre , Fumey Bruno , de Bellefon Claude 
Published: February 2006

AbstractThe global gas‐liquid‐solid volumetric mass‐transfer coefficient KLa of a catalytic multiphase microstructured film contactor, featuring 5 μm dimensions, a 155 μm liquid film thickness, and a 15 μm thin catalytic layer is determined, using the very fast hydrogenation of α‐methylstyrene with a Pd/γ‐alumina catalyst. The volumetric mass‐transfer coefficients measured experimentally fall in the range 0.8 – 1.6 s−1 above that predicted by the film model and those obtained from a CFD (3‐D model) simulation, and from an analytical solution. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Asymmetrische Katalyse durch chirale Wasserstoffbrückendonoren
Authors: Taylor Mark S. , Jacobsen Eric N. 
Published: February 2006

AbstractWasserstoffbrücken bestimmen die Struktur eines großen Teils der uns umgebenden Materie. Die ungewöhnlichen Eigenschaften von flüssigem Wasser, die Faltung von Proteinen zu stabilen dreidimensionalen Strukturen, die DNA‐Basenpaarung und die Bindung von Liganden an Rezeptoren beruhen auf dieser nichtkovalenten Wechselwirkung. Neben ihrer strukturgebenden Rolle haben Wasserstoffbrücken auch entscheidende Funktionen bei katalytischen Prozessen. Enzyme beschleunigen viele biochemische Reaktionen, indem sie die Elektronendichte eines Elektrophils durch Bildung einer Wasserstoffbrücke verringern und es so für den nucleophilen Angriff aktivieren. In der organischen Synthese hat man das Potenzial dieser Strategie erkannt, und niedermolekulare Verbindungen, insbesondere chirale Wasserstoffbrückendonoren, wurden als Katalysatoren für enantioselektive Synthesen entwickelt. Dieser Aufsatz zeigt, welche strukturellen und mechanistischen Merkmale in wasserstoffbrückenvermittelten Katalyseprozessen zu hohen Enantioselektivitäten führen.
Asymmetric Catalysis by Chiral Hydrogen‐Bond Donors
Authors: Taylor Mark S. , Jacobsen Eric N. 
Published: February 2006

AbstractHydrogen bonding is responsible for the structure of much of the world around us. The unusual and complex properties of bulk water, the ability of proteins to fold into stable three‐dimensional structures, the fidelity of DNA base pairing, and the binding of ligands to receptors are among the manifestations of this ubiquitous noncovalent interaction. In addition to its primacy as a structural determinant, hydrogen bonding plays a crucial functional role in catalysis. Hydrogen bonding to an electrophile serves to decrease the electron density of this species, activating it toward nucleophilic attack. This principle is employed frequently by Nature's catalysts, enzymes, for the acceleration of a wide range of chemical processes. Recently, organic chemists have begun to appreciate the tremendous potential offered by hydrogen bonding as a mechanism for electrophile activation in small‐molecule, synthetic catalyst systems. In particular, chiral hydrogen‐bond donors have emerged as a broadly applicable class of catalysts for enantioselective synthesis. This review documents these advances, emphasizing the structural and mechanistic features that contribute to high enantioselectivity in hydrogen‐bond‐mediated catalytic processes.
On the development of name search techniques for Arabic
Authors: Aqeel Syed Uzair , Beitzel Steve , Jensen Eric , Grossman David , Frieder Ophir 
Published: February 2006

AbstractThe need for effective identity matching systems has led to extensive research in the area of name search. For the most part, such work has been limited to English and other Latin‐based languages. Consequently, algorithms such as Soundex and n‐gram matching are of limited utility for languages such as Arabic, which has vastly different morphologic features that rely heavily on phonetic information. The dearth of work in this field is partly caused by the lack of standardized test data. Consequently, we have built a collection of 7,939 Arabic names, along with 50 training queries and 111 test queries. We use this collection to evaluate a variety of algorithms, including a derivative of Soundex tailored to Arabic (ASOUNDEX), measuring effectiveness by using standard information retrieval measures. Our results show an improvement of 70% over existing approaches.
Probabilistic topic decomposition of an eighteenth‐century American newspaper
Authors: Newman David J. , Block Sharon 
Published: February 2006

AbstractWe use a probabilistic mixture decomposition method to determine topics in thePennsylvania Gazette, a major colonial U.S. newspaper from 1728–1800. We assess the value of several topic decomposition techniques for historical research and compare the accuracy and efficacy of various methods. After determining the topics covered by the 80,000 articles and advertisements in the entire 18th century run of theGazette, we calculate how the prevalence of those topics changed over time, and give historically relevant examples of our findings. This approach reveals important information about the content of this colonial newspaper, and suggests the value of such approaches to a more complete understanding of early American print culture and society.
Combined Fourier transform infrared and Raman spectroscopic approach for identification of multidrug resistance phenotype in cancer cell lines
Authors: Krishna C. Murali , Kegelaer Gregory , ADT Isabelle , Rubin Sylvain , Kartha Vasudevan B. , Manfait Michel , Sockalingum Ganesh D. 
Published: February 2006

AbstractCancer cells escape cytotoxic effects of anticancer drugs by a process known as multidrug resistance (MDR). Identification of cell status by less time‐consuming methods can be extremely useful in patient management and treatment. This study aims at evaluating the potentials of vibrational spectroscopic methods to perform cell typing and to differentiate between sensitive and resistant human cancer cell lines, in particular those that exhibit the MDR phenotype. Micro‐Raman and Fourier transform infrared (FTIR) spectra have been acquired from the sensitive promyelocytic HL60 leukemia cell line and two of its subclones resistant to doxorubicin (HL60/DOX) and daunorubicin (HL60/DNR), and from the sensitive MCF7 breast cancer cell line and its MDR counterpart resistant to verapamil (MCF7/VP). Principal components analysis (PCA) was employed for spectral comparison and classification. Our data show that cell typing was feasible with both methods, giving two distinct clusters for HL60‐ and MCF7‐sensitive cells. In addition, phenotyping of HL60 cells, i.e., discriminating between the sensitive and MDR phenotypes, was attempted by both methods. FTIR could not only delineate between the sensitive and resistant HL60 cells, but also gave two distinct clusters for the resistant cells, which required a two‐step procedure with Raman spectra. In the case of MCF7 cell lines, both the sensitive and resistant phenotypes could be differentiated very efficiently by PCA analysis of their FTIR and Raman point spectra. These results indicate the prospective applicability of FTIR and micro‐Raman approaches in the differentiation of cell types as well as characterization of the cell status, such as the MDR phenotype exhibited in resistant leukemia cell lines like HL60 and MCF7. © 2006 Wiley Periodicals, Inc. Biopolymers 82: 462–470, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Influence of sequential oligopeptide carriers on the bioactive structure of conjugated epitopes: Comparative study of the conformation of a Herpes simplex virus glycoprotein gD‐1 epitope in the free and conjugated form, and protein “built‐in” crystal structure
Authors: Krikorian Dimitrios , Stavrakoudis Athanassios , Biris Nikolaos , Sakarellos Constantinos , Andreu David , de Oliveira Eliandre , Mezö Gábor , Majer Zsuzsa , Hudecz Ferenc , Welling‐Wester Sytske , Cung Manh Thong , Tsikaris Vassilios 
Published: February 2006

AbstractSynthetic carriers play an important role in immunogen presentation, due to their ability of inducing improved and specific responses to conjugated epitopes. Their influence on the bioactive conformation of the epitope, though admittedly crucial for relevant in vitro and in vivo applications, is difficult to evaluate, given the usual lack of information on the complex conformational features determined by the nature of the carrier and the mode of ligation. Using the Herpes simplex virus glycoprotein D‐1 epitope (Leu9–Lys–Nle–Ala–Asp–Pro–Asn–Arg–Phe–Arg–Gly–Lys–Asp–Leu22) as a model, we have performed a detailed conformational analysis on the free epitope peptide in solution and on three constructs in which the epitope was conjugated to sequential oligopeptide carriers {Ac–[Lys–Aib–Gly]4–OH (SOC4)} (through either a thioether or an amide bond; Ac: acetyl) and polytuftsin oligomers {H–[Thr–Lys–Pro–Lys–Gly]4–NH2 (T20)}, (through a thioether bond). The analysis of the epitope conformation in the parent protein, in carrier‐conjugated and free form, suggests that the β‐turn structure of the –Asp13–Pro–Asn–Arg16– segment is highly conserved and independent of the epitope form. However, small conformational variations were observed at the C‐terminal part of the epitope, depending on the nature of the carrier. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 383–399, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Mechanism of Action of Tubulysin, an Antimitotic Peptide from Myxobacteria
Authors: Khalil Mohamed W. , Sasse Florenz , Lünsdorf Heinrich , Elnakady Yasser A. , Reichenbach Hans 
Published: February 2006

AbstractTubulysin A is a highly cytotoxic peptide with antimitotic activity that induces depletion of cell microtubules and triggers the apoptotic process. Treated cells accumulated in the G2/M phase. Tubulysin A inhibited tubulin polymerization more efficiently than vinblastine and induced depolymerization of isolated microtubule preparations. Microtubule depolymerization could not be prevented by preincubation with epothilone B and paclitaxel, neither in cell‐free systems nor in cell lines. In competition experiments, tubulysin A strongly interfered with the binding of vinblastine to tubulin in a noncompetitive way; the apparent Ki was 3 μM. Electron microscopy investigations showed that tubulysin A induced the formation of rings, double rings, and pinwheel structures. The mode of action of tubulysin A resembled that of peptide antimitotics dolastatin 10, phomopsin A, and hemiasterlin. Efforts are underway to develop this new group of compounds as anticancer drugs.
Cyclodextrin‐Derived Mimic of Glutathione Peroxidase Exhibiting Enzymatic Specificity and High Catalytic Efficiency
Authors: Dong Ze‐Yuan , Huang Xin , Mao Shi‐Zhong , Liang Kai , Liu Jun‐Qiu , Luo Gui‐Min , Shen Jia‐Cong 
Published: February 2006

AbstractTo elucidate the relationships between molecular recognition and catalytic ability, we chose three assay systems using three different thiol substrates, glutathione (GSH), 3‐carboxyl‐4‐nitrobenzenethiol (CNBSH), and 4‐nitrobenzenethiol (NBSH), to investigate the glutathione peroxidase (GPx) activities of 2,2′‐ditellurobis(2‐deoxy‐β‐cyclodextrin) (2‐TeCD) in the presence of a variety of structurally distinct hydroperoxides (ROOH), H2O2, tert‐butyl peroxide (tBuOOH), and cumene peroxide (CuOOH), as the oxidative reagent. A comparative study of the three assay systems revealed that the cyclodextrin moiety of the GPx mimic 2‐TeCD endows the molecule with selectivity for ROOH and thiol substrates, and hydrophobic interactions are the most important driving forces in 2‐TeCD complexation. Furthermore, in the novel NBSH assay system, 2‐TeCD can catalyze the reduction of ROOH about 3.4×105 times more efficiently than diphenyl diselenide (PhSeSePh), and its second‐order rate constants for thiol are similar to some of those of native GPx. This comparative study confirms that efficient binding of the substrate is essential for the catalytic ability of the GPx mimic, and that NBSH is the preferred thiol substrate of 2‐TeCD among the chosen thiol substrates. Importantly, the proposed mode of action of 2‐TeCD imitates the role played by several possible noncovalent interactions between enzymes and substrates in influencing catalysis and binding.
The Characterisation of Molecular Alkali‐Metal Azides
Authors: Ogden J. Steven , Dyke John M. , Levason William , Ferrante Francesco , Gagliardi Laura 
Published: February 2006

AbstractMatrix isolation infrared (IR) studies have been carried out on the vaporisation of the alkali‐metal azides MN3 (M = Na, K, Rb and Cs). The results show that under high vacuum conditions, molecular KN3, RbN3 and CsN3 are present as stable high‐temperature vapour species, together with variable amounts of nitrogen gas and the corresponding metal atoms. The characterisation of these molecular azides is supported by ab initio molecular orbital calculations and density functional theory (DFT) calculations, and for CsN3 in particular, by the detection of the isotopomers Cs(14N15N14N) and Cs(15N14N14N). The IR spectra are assigned to a “side‐on” (C2v) structure by comparison with the spectral features predicted both by vibrational analysis and calculation. The most intense IR features for KN3, RbN3 and CsN3 isolated in nitrogen matrices lie at 2005, 2004.4 and 2002.2 cm−1, respectively, and correspond to the N3 asymmetric stretch. The N3 bending mode in CsN3 is identified at 629 cm−1. An additional feature routinely observed in these experiments occurred at approximately 2323 cm−1 and is assigned to molecular N2, perturbed by the close proximity of an alkali‐metal atom. The position of this band appeared to show very little cation dependence, but its intensity correlated with the extent of sample thermal decomposition.