bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Anterior Occlusal Characteristics on Self-perceived Dental Appearance in Young Adults
Authors: Bernabe Eduardo , Flores-Mir Carlos
Published: May 2007

Objective: To determine the individual and combined influence of some anterior occlusal characteristics on self-perceived dental appearance in a sample of young adults.

Materials and Methods: This cross-sectional study was conducted at a dental clinic of a private university in Lima, Peru. A total of 267 first-year students (16 to 25 years old) were randomly selected. A visual analog scale (VAS) was used to determine the self-perceived dental appearance. Clinical examinations were conducted to determine incisal irregularity, anterior dentoalveolar spacing, midline diastema, anterior missing teeth, overjet, and overbite. Simple and multiple linear regression analyses were performed to determine the individual and combined influence of each anterior occlusal characteristic on self-perceived dental appearance.

Results: From the eight occlusal characteristics and two covariables evaluated, only maxillary and mandible incisal irregularity (P = .001 and .002 respectively), presence of anterosuperior spacing (P < .001), and number of missing anterior teeth (P = .003) were inversely associated with self-perceived dental appearance, whereas gender (male) was directly associated to the dependent variable (P = .021). Specifically, anterior maxillary spacing, maxillary incisal irregularity, mandible incisal irregularity, and the number of missing teeth were, in that order, the anterior occlusal characteristics with the most negative influence on self-perceived dental appearance.

Conclusions: This study confirmed that occlusal characteristics in the anterior portion of the mouth play a role on dental esthetics. However, it should be emphasized that their grouped influence is minimal (less than 20%).
Smile Attractiveness
Authors: Van der Geld Pieter , Oosterveld Paul , Van Heck Guus , Kuijpers-Jagtman Anne Marie
Published: May 2007

Objectives: To investigate self-perception of smile attractiveness and to determine the role of smile line and other aspects correlated with smile attractiveness and their influence on personality traits.

Subjects and Methods: Participants judged their smile attractiveness with a patient-specific questionnaire. The questionnaire contained a spontaneous smiling photograph of the participant. Objective smile-line height was measured using a digital videographic method for smile analysis. Personality was assessed with the Dutch Personality Index.

Results: Cronbach's α for the smile judgment questionnaire was .77. The results showed that size of teeth, visibility of teeth, and upper lip position were critical factors in self-perception of smile attractiveness (social dimension). Color of teeth and gingival display were critical factors in satisfaction with smile appearance (individual dimension). Participants, smiling with teeth entirely displayed and some gingival display (two to four millimeters), perceived their smile line as most esthetic. Smiles with disproportional gingival display were judged negatively and correlated with the personality characteristics of neuroticism and self-esteem. Visibility and position of teeth correlated with dominance.

Conclusion: The results of this research underpin the psychosocial importance and the dental significance of an attractive smile.
Outcome of Orthognathic Surgery in Chinese Patients
Authors: Chew Ming Tak , Sandham Andrew , Soh Jen , Wong Hwee Bee
Published: May 2007

Objective: To evaluate the outcome of orthognathic surgery by objective cephalometric measurement of posttreatment soft-tissue profile and by subjective evaluation of profile esthetics by laypersons and clinicians.

Materials and Methods: The sample consisted of 30 Chinese patients who had completed combined orthodontic and orthognathic surgical treatment. The posttreatment cephalograms of these patients were analyzed with respect to profile convexity, facial height, and lip contours and these were compared to the previously established esthetic norms. Line drawings of the soft-tissue profile were displayed to a panel comprising six laypersons and six clinicians who scored the esthetics of each profile using a 7-point scale.

Results: Complete normalization of cephalometric soft-tissue variables was not achieved with orthognathic surgery in most patients, with four of the six soft-tissue cephalometric measurements showing significant differences compared to the esthetic norms. There were good correlations in the esthetic scores between laypersons and clinicians, even though clinicians tend to rate the profiles more favorably. Facial convexity and facial height did not significantly influence the subjective scores of both the laypersons and clinicians. Lower lip protrusion was the only cephalometric variable that significantly influenced clinicians' assessment of profile esthetics (P < .01).

Conclusions: Profile convexity and lower facial height proportion had little influence on both lay and professional perception of profile esthetics. Lower lip position is the only cephalometric variable that significantly influenced clinicians' assessment of profile esthetics.
Influence of Self-etchant Application Time on Bracket Shear Bond Strength
Authors: Ostby Adam Wade , Bishara Samir E. , Laffoon John , Warren John J.
Published: May 2007

Objective: To determine the influence of self-etching primer (SEP) application time on the shear bond strength of orthodontic brackets.

Materials and Methods: Forty human molars were cleaned, mounted, and randomly divided into two groups. The same SEP, adhesive, and brackets were used in both groups. Twenty teeth were conditioned following the manufacturers' recommendations by rubbing the SEP on the enamel surface for 3 to 5 seconds. The remaining 20 teeth were conditioned using the same SEP, but the application time was increased to 15 seconds. The teeth were debonded within half an hour following initial bonding using a universal testing machine. After debonding, the amount of residual adhesive remaining on the tooth was determined. Student's t-test was used to compare the shear bond strength (SBS) of the two groups, and the χ2 test was used to compare the Adhesive Remnant Index (ARI) scores for the two adhesive systems.

Results: The mean SBS of the brackets bonded to the teeth subjected to the SEP for 3 to 5 seconds was 8.0 ± 4.6 MPa and was not significantly different (t = −0.69, P = .494) from the SBS of the brackets bonded using a 15-second SEP application time (x̄ = 8.9 ± 3.4 MPa). The comparisons of the ARI scores between the two groups (χ2 = 2.16) indicated that bracket failure mode was not significantly different (P = .340) for both groups, and most failures were at the bracket-adhesive interface.

Conclusion: The present findings indicate that increasing the SEP application from 3 to 5 seconds to 15 seconds does not result in a significant increase in SBS.
Mandibular Asymmetry in Different Occlusion Patterns
Authors: Sezgin Omer Said , Celenk Peruze , Arici Selim
Published: May 2007

Objective: To investigate the effects of different occlusion types on the mandibular asymmetry in young individuals.

Materials and Methods: Mandibular asymmetry measurements were performed on the panoramic radiographs of 189 subjects (104 females and 85 males; age range, 11–15 years), with different occlusion patterns. The subjects were divided into five groups according to the occlusion types, namely, Angle Class I (Cl I), Class II division 1 (Cl II/1), Class II division 2 (Cl II/2), Class III (Cl III), and normal occlusions. The Kruskal-Wallis test was used to determine the possible statistically significant differences between the groups for condyle, ramus, and condyle-plus-ramus asymmetry index measurements. Identified differences between groups were further analyzed using the Mann-Whitney U-test at the 95% confidence interval (P < .05).

Results: There were no statistically significant differences between male and female subjects. The Kruskal-Wallis test showed that the occlusion type had a significant effect on the condylar asymmetry. In Cl II/1 cases, condylar asymmetry values were significantly different from the values of Cl II/2 and Cl III malocclusion and normal occlusion types. The normal occlusion control group was significantly different from those of Cl II/1 and the Cl I malocclusion groups.

Conclusion: Cl II/1 malocclusion has a significant effect on the condylar asymmetry index when compared to Cl II/2 and Cl III malocclusion and normal occlusion types. However, the mean condylar asymmetry index value in Cl II/1 malocclusion was not different from Cl I malocclusion.
Invisalign and Traditional Orthodontic Treatment Postretention Outcomes Compared Using the American Board of Orthodontics Objective Grading System
Authors: Kuncio Daniel , Maganzini Anthony , Shelton Clarence , Freeman Katherine
Published: May 2007

Objective: To compare the postretention dental changes between patients treated with Invisalign and those treated with conventional fixed appliances.

Materials and Methods: This is a comparative cohort study using patient records of one orthodontist in New York City. Two groups of patients were identified that differed only in the method of treatment (Invisalign and Braces group). Dental casts and panoramic radiographs were collected and analyzed using the objective grading system (OGS) of the American Board of Orthodontics (ABO). The cases were evaluated immediately after appliance removal (T1) and at a postretention time (T2), three years after appliance removal. All patients had completed active orthodontic treatment and had undergone at least one year of retention. A Wilcoxon rank sum test was used to evaluate differences in treatment outcomes between the groups for each of the eight categories in the OGS, including four additional subcategories in the alignment category. A Wilcoxon signed rank test was used to determine the significance of changes within each group from T1 to T2.

Results: The change in the total alignment score in the Invisalign group was significantly larger than that for the Braces group. There were significant changes in total alignment and mandibular anterior alignment in both groups. There were significant changes in maxillary anterior alignment in the Invisalign group only.

Conclusions: In this sample for this period of observation, patients treated with Invisalign relapsed more than those treated with conventional fixed appliances.
Three Cements Used for Orthodontic Banding of Porcelain Molars
Authors: Herion Tracy , Ferracane Jack L. , Covell David A.
Published: May 2007

Objective: Objectives of this study were to (1) compare the mean shear-peel bond strength of orthodontic bands luted to porcelain molar denture teeth with glass ionomer cement (GIC), resin-modified glass ionomer cement (RMGIC), or compomer cement; (2) assess the amount of cement remaining on the teeth after debanding; and (3) compare the survival times of the cemented bands subject to mechanical fatigue.

Materials and Methods: Sixty banded denture teeth (20 per cement group) were used to determine shear-peel bond strength, and 30 banded denture teeth (10 per cement group) were used to determine fatigue survival time. Shear-peel bond strength was determined with a universal testing machine, and groups were compared by one-way analysis of variance. The amount of cement remaining on the teeth after band removal was scored, and a chi-square test was used to compare groups. Fatigue testing was conducted in a ball mill, and a log-rank test was used to compare differences in survival times.

Results: No differences were found in mean shear-peel bond strength among the three groups. The amount of cement remaining on the teeth varied between the compomer and GIC groups (P = .01), with more compomer cement remaining relative to GIC. The mean survival times of bands cemented with compomer or RMGIC were longer than for bands cemented with GIC (P < .001).

Conclusion: The findings show that on porcelain teeth the band cements have comparable mean shear-peel bond strengths, but that band retention with RMGIC and compomer cement are superior to GIC when subjected to simulated mechanical fatigue.
Saliva Contamination Effect on Shear Bond Strength of Self-etching Primer with Different Debond Times
Authors: Turk Tamer , Elekdag-Turk Selma , Isci Devrim , Cakmak Fethiye , Ozkalayci Nurhat
Published: May 2007

Objective: To evaluate shear bond strengths (SBSs) of a self-etching primer (SEP) following saliva contamination at different stages of bonding at debond times of 5, 15, and 30 minutes and 24 hours.

Materials and Methods: Two-hundred forty human premolars were divided into four groups: group 1, uncontaminated; group 2, saliva contamination after priming; group 3, saliva contamination before priming; and group 4, saliva contamination before and after priming. Four subgroups according to debond times of 5, 15, 30 minutes and 24 hours were composed. Metal brackets were bonded with an SEP (Transbond Plus) and light-cure adhesives paste (Transbond XT). SBS values and the adhesive remnants were determined.

Results: The highest SBS was obtained at a debond time of 24 hours for the control group. This was significantly different from the other groups. SBSs at 5, 15, and 30 minutes showed no significant difference from each other in the control group (P > .05). Lowest SBSs were obtained at a debond time of 5 minutes for groups 1, 2, 3, and 4 (8.38, 7.10, 7.06, and 6.26 MPa, respectively) and were not significantly different from each other (P > .05). SBSs at 24 hours were not significantly different from each other for groups 2, 3, and 4 (P > .05). Significant differences were found in the adhesive remnant (P < .001).

Conclusions: SEP (Transbond Plus) may produce clinically acceptable bracket bonding after 5, 15, and 30 minutes from time of placement on the teeth, even with light and heavy saliva contamination.
Acid Resistance of Erbium-doped Yttrium Aluminum Garnet Laser–Treated and Phosphoric Acid–Etched Enamels
Authors: Kim Jung-Ho , Kwon Oh-Won , Kim Hyung-Il , Kwon Yong Hoon
Published: May 2007

Objective: To compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser ablation and of phosphoric acid etching on the in vitro acid resistance of bovine enamel.

Materials and Methods: Teeth were polished to make the surface flat. The polished enamel was either etched with 37% phosphoric acid for 30 seconds or ablated with a single 33 J/cm2 pulse from an Er:YAG laser. The control specimens were free from acid etching and laser ablation. Changes in crystal structure, dissolved mineral (calcium [Ca] and phosphorus [P]) contents, and calcium distribution in the enamel subsurface after a pH-cycling process were evaluated.

Results: After laser treatment, poor crystal structures improved without forming any new phases, such as tricalcium phosphates. Among the tested enamels, dissolved mineral contents were significantly different (P < .05). Er:YAG laser–treated enamels had the lowest mineral dissolution (Ca, 13.78 ppm; P, 6.33 ppm), whereas phosphoric acid–etched enamels had the highest (Ca, 15.90 ppm; P, 7.33 ppm). The reduction rate and reduced depth of calcium content along the subsurface were lowest in Er:YAG laser–treated enamels.

Conclusion: The Er:YAG laser–treated enamels are more acid resistant to acid attack than phosphoric acid–etched enamels.
A Fused Maxillary Central Incisor with Dens Evaginatus as a Talon Cusp
Authors: Danesh Gholamreza , Schrijnemakers Tine , Lippold Carsten , Schäfer Edgar
Published: May 2007

This report presents a rare case of concurrence of dens evaginatus and dental fusion affecting the maxillary right upper central incisor of a 9-year-old male patient. An association of dens evaginatus and dental fusion within the same tooth is rare. In this case, an orthopantomogram, a lateral cephalogram, intraoral radiographs, and a magnetic resonance tomogram were made to obtain a proper diagnosis and to confirm the exact path of the root canals. Because of a forced bite, an orthodontic treatment involving cusp reduction was initiated. During the cusp reduction, no traumatic intraoperative exposure of pulp tissue occurred, and no endodontic or surgical treatment procedures were necessary. After a multibracket treatment, a harmonious integration of the tooth in the upper dental arch was achieved.
Short-term Effect of Mastic Gum on Salivary Concentrations of Cariogenic Bacteria in Orthodontic Patients
Authors: Aksoy Alev , Duran Nizami , Toroglu Serdar , Koksal Fatih
Published: May 2007

Objective: To determine antibacterial activity of chewing mastic gum against the salivary levels of Streptococcus mutans, the total number of viable bacteria, and lactobacilli in patients undergoing therapy with fixed orthodontic appliances.

Materials and Methods: In this study, the levels of S mutans, lactobacilli, and total cultivated bacteria were measured before and after chewing mastic gum. The antibacterial effects of chewing mastic gum against these microorganisms in saliva were compared with a placebo gum. The counts for orthodontically treated patients were evaluated before chewing gum; just after chewing gum; and after 45, 75, 105, and 135 minutes. Saliva samples taken from the patients were inoculated onto trypticase-yeast-cystine-bacitracin agar for mutans streptococci and onto Rogosa agar for lactobacilli. The agar plates were incubated for 48 hours anaerobically at 37°C. The total number of viable bacteria was then counted.

Results: Just after chewing the mastic gum for 15 minutes, a significant decrease of total bacteria and S mutans was observed (P < .001). The reduction in lactobacilli was not significant at later first stage (P > .05). However, at the end of 135 minutes, there were significantly fewer S mutans (P < .001), total viable bacteria (P < .001), and lactobacilli (P < .001) in the oral cavity after chewing mastic gum than after chewing paraffin (P < .001). The results show that chewing mastic gum decreased the total viable bacteria, S mutans, and lactobacilli in saliva in orthodontically treated patients with fixed appliances.

Conclusion: Chewing mastic gum might be useful in preventing caries lesions.
Micropatterned Polypyrrole: A Combination of Electrical and Topographical Characteristics for the Stimulation of Cells
Authors: Gomez N. , Lee J. Y. , Nickels J. D. , Schmidt C. E.
Published: May 2007

Electrically conducting polymers such as polypyrrole (PPy) are important biomaterials in neural engineering applications, including neural probes, nerve conduits, and scaffolds for tissue and nerve regeneration. Surface modification of these polymers can introduce other valuable characteristics for neural interfacing in addition to electrical conductivity, such as topographical features and chemical bioactivity. Here, the patterning of PPy to create topographical cues for cells is reported. In particular, 1 and 2 μm wide PPy microchannels are fabricated using electron‐beam (e‐beam) lithography and electropolymerization. A systematic analysis of parameters controlling PPy micropatterning is performed, and finds that microchannel depth, roughness, and morphology are highly dependent on the e‐beam writing current, polymerization current, PPy/dopant concentrations, and the polymerization time. Embryonic hippocampal neurons cultured on patterned PPy polarize (i.e., defined an axon) faster on this modified material, with a twofold increase in the number of cells with axons compared to cells cultured on unmodified PPy. These topographical features also have an effect on axon orientation but do not have a significant effect on overall axon length. This is the first investigation that studies controlled PPy patterning with small dimensions (i.e., less than 5 μm) for biological applications, which demonstrates the relevance of expanding microelectronic materials and techniques to the biomedical field.
A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings
Authors: Rajesh K. , Shajesh P. , Seidel O. , Mukundan P. , Warrier K. G. K.
Published: May 2007

Synthesis of rod‐shaped nanocrystalline lanthanum phosphate with an average length of 40 nm even after calcination at 400 °C has been realized through a room‐temperature aqueous sol–gel process. The sol is characterized by particle‐size, zeta‐potential, and viscosity measurements. Gelation of the sol is induced by ammonia. The lanthanum phosphate phase‐formation process is followed by thermal, Fourier‐transform IR, and X‐ray diffraction analysis. Transmission electron microscopy shows that the sol and gel particles have a rod‐shaped morphology and comparable particle sizes. Using the Scherrer equation a crystallite size of 11 nm is obtained for the gel powder calcined at 400 °C and Brunauer–Emmett–Teller (BET) nitrogen‐adsorption analysis showed a high specific surface area of 100 m2 g–1. Ammonia temperature‐programmed desorption measurements show that the density of Lewis acid sites is four times higher than ever reported in the case of lanthanum phosphates. The catalytic activity of the above sample is demonstrated by using it as a Lewis‐acid catalyst in an acetal‐formation reaction with a very good yield of 85 %. The sol is used to develop nanocoatings on a glass surface and the morphology of the coatings is investigated using atomic force microscopy and scanning electron microscopy. The microstructure of the coating confirmed the rod‐shaped nature of the sol particles. The coating was uniform with a thickness of about 55 nm.
Luminescence and Amplified Stimulated Emission in CdSe–ZnS‐Nanocrystal‐Doped TiO2 and ZrO2 Waveguides
Authors: Jasieniak J. , Pacifico J. , Signorini R. , Chiasera A. , Ferrari M. , Martucci A. , Mulvaney P.
Published: May 2007

A reproducible route for the preparation of high‐quality CdSe–ZnS‐doped titania and zirconia waveguides is presented. The optical properties of the resultant composite materials are found to be sensitive to the semiconducting properties of the host matrix. Titania‐based composites are seen to be inherently photounstable because of photoelectron injection into the bulk matrix and subsequent nanocrystal (NC) oxidation. In comparison, zirconia composites are significantly more robust with high photoluminescence (PL) retained for annealing temperatures up to 300 °C. Both titania and zirconia composite waveguides exhibit amplified stimulated emission (ASE); however only zirconia‐based waveguides exhibit long‐term photostability (loss of less than 30 % ASE intensity after more than 40 min continuous excitation). We conclude that the low electron affinity of zirconia and its inherent high refractive index makes it an ideal candidate for NC‐based optical waveguides.
Gray/nongray gas radiation modeling in steam cracker CFD calculations
Authors: Stefanidis G. D. , Merci B. , Heynderickx G. J. , Marin G. B.
Published: May 2007

A constant composition gray gas and a constant composition nongray gas radiation model are developed and applied in computational fluid dynamic simulations of an industrial scale steam cracking furnace. Both models are based on the exponential wide band model. The gray gas model simplification, commonly used for simulations of industrial applications, is found to have an effect on predicted variable fields like flue gas flow, temperature, and heat flux to the reactor tubes. When the nongray gas model is used, higher energy absorption by the flue gas in the furnace and lower energy transfer to the process gas in the reactor tubes is calculated because of the high absorption coefficients in the strongly absorbing bands of 2.7 and 4.3 μm. Thus, the calculated thermal efficiency increases from 37.5% when using the nongray gas model to 42.6% when using the gray gas model. A 5% difference in the thermal efficiency is large considering the scale and the importance of the process and should be taken into account by the furnace designer. It is also shown that although both models reproduce the basic characteristics of the flow pattern in the furnace, quantitative differences in the flue gas speed are predicted in some regions of the furnace domain. © 2007 American Institute of Chemical Engineers AIChE J, 2007
The accuracy of activated partial thromboplastin times when drawn through a peripherally inserted central catheter
Authors: Rondina Matthew T. , Markewitz Boaz , Kling Stephen J. , Nohavec Robert , Rodgers George M.
Published: May 2007

The peripherally‐inserted central catheter (PICC) is used commonly in hospitalized patients. The presence of heparin within the PICC lumen, however, may affect the results of coagulation indices when measured on blood drawn through it. In 41 patients with a PICC inserted as part of their medical care, we compared activated partial thromboplastin times (aPTTs) measured on blood drawn through the PICC to blood drawn through a peripheral venipuncture (VP). There were no clinically significant differences between aPTT values from the two samples. Using the PICC to obtain blood for the measurement of aPTT is accurate and may reduce the need for peripheral VPs. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
The use of desmopressin as a hemostatic agent: A concise review
Authors: Franchini Massimo
Published: May 2007

Desmopressin, a synthetic derivative of the antidiuretic hormone vasopressin, is the treatment of choice for most patients with von Willebrand disease and mild hemophilia A. Moreover, the compound has been shown to be useful in a variety of inherited and acquired hemorrhagic conditions, including some congenital platelet function defects, chronic liver disease, uremia, and hemostatic defects induced by the therapeutic use of antithrombotic drugs such as aspirin and ticlopidine. Finally, desmopressin has been used as a blood saving agent in patients undergoing operations characterized by large blood loss and transfusion requirements, but studies suggest that this is not as effective as other methods. This review briefly summarizes the current clinical indications on the use of desmopressin as a hemostatic agent. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Prevention of red cell alloimmunization by CD25 regulatory T cells in mouse models
Authors: Yu Jin , Heck Susanne , Yazdanbakhsh Karina
Published: May 2007

Transfusion therapy is currently an effective therapeutic intervention in a number of diseases, including sickle cell disease. However, its use is complicated by a high incidence of red blood cell (RBC) alloimmunization in the transfusion recipients. The identification of T regulatory cells (Tregs) among the CD4+ CD25+ T cell subset as key regulators of peripheral tolerance in mice as well as humans has opened an exciting era in the prevention and treatment of autoimmune disease and for improving organ transplantation. However, their potential in inducing transfusion tolerance remains to be explored. We used red cells from mice transgenic for human glycophorin A blood group antigen as donor cells and transfused wild‐type mice to induce alloantibodies, as an experimental system to study RBC alloimmunization. We found that depletion with anti‐CD25 enhanced the alloantibody production, indicating that CD25 Tregs play an important role in regulation of alloantibody responses. More importantly, adoptive transfer of purified population of CD4+CD25+ but not CD4+CD25− cells from naïve mice prevented the induction of IgG and IgM alloantibody production in transfusion recipients, with a concomitant reduction in activated splenic B cells and macrophages. Similarly, adoptive transfer of purified populations of CD4+CD25+ cells from naïve mice into naïve syngeneic recipients inhibited the anti‐Ig response to rat RBCs in the recipients but transfer of control CD4+CD25− cells did not. Altogether, our results demonstrate that Tregs participate in the control of transfusion‐associated RBC alloantibody responses, opening up the possibility that Treg immunotherapy may be exploited for suppressing transfusion immunization events. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Mating patterns amongst Siberian reindeer herders: Inferences from mtDNA and Y‐chromosomal analyses
Authors: Pakendorf Brigitte , Novgorodov Innokentij N. , Osakovskij Vladimir L. , Stoneking Mark
Published: May 2007

The Evenks and Evens, who speak closely related languages belonging to the Northern Tungusic branch of the Tungusic family, are nomadic reindeer herders and hunters. They are spread over an immense territory in northeastern Siberia, and consequently different subgroups are in contact with diverse peoples speaking Samoyedic, Turkic, Mongolic, Chukotka‐Kamchatkan, and Yukaghir languages. Nevertheless, the languages and culture of the Evenks and Evens are similar enough for them to have been classified as a single ethnic group in the past. This linguistic and cultural similarity indicates that they may have spread over their current area of habitation relatively recently, and thus may be closely related genetically. On the other hand, the great distances that separate individual groups of Evens and Evenks from each other might have led to preferential mating with geographic neighbors rather than with linguistically related peoples. In this study, we assess the correlation between linguistic and genetic relationship in three different subgroups of Evenks and Evens, respectively, via mtDNA and Y‐chromosomal analyses. The results show that there is some evidence of a common origin based on shared mtDNA lineages and relatively similar Y‐haplogroup frequencies amongst most of the Evenk and Even subgroups. However, there is little sharing of Y‐chromosomal STR haplotypes, indicating that males within Evenk and Even subgroups have remained relatively isolated. There is further evidence of some female admixture in different Even subgroups with their respective geographic neighbors. However, the Tungusic groups, and especially the Evenks, show signs of genetic drift, making inferences about their prehistory difficult. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
Muscle markers revisited: Activity pattern reconstruction with controls in a central California Amerind population
Authors: Weiss Elizabeth
Published: May 2007

Anthropologists frequently use musculoskeletal stress markers to reconstruct past activity patterns. Yet, researchers have called into question the reliability of muscle marker measurements in part because body size and age affect muscle marker scores. In this study, the author examined an aggregate upper limb muscle marker to determine if after controlling for the effects of body size and age, one could reconstruct activity patterns of a prehistoric Amerind population. Analyses were made of a sample of 102 (43 males, 59 females) prehistoric central California Amerinds. Muscle markers were measured using two‐point observer rating scales; body size was measured by humeral articular surfaces; age and sex were determined previously through standard procedures. Using sex separated rankings and partial correlations, disaggregated muscle markers were examined for correlations with age and size to determine if specific muscle markers may be useful in pinpointing to activity patterns. Aggregate upper limb muscle marker correlated with: age, r = 0.44; humeral size, r = 0.44; and sex, r = 0.43; Ps < 0.001. Older individuals had greater muscle markers, as did larger individuals, and males. Rankings seemed to be confounded by the effect size had on the muscle markers. However, based on partial correlations controlling for size and age, the differences that remained between males and females could be used to reconstruct male activities of throwing in hunting and interpersonal aggression acts. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
Composite estimates of physiological stress, age, and diabetes in American Samoans
Authors: Crews Douglas E.
Published: May 2007

Composite estimates of physiological stress such as allostatic load (AL) were developed to help assess cumulative impacts of psychosocial and physical stressors on the body. Physiological responses to stress generally accelerate somatic wear‐and‐tear and chronic degenerative conditions (CDCs). Following McEwen (Neuropsychopharmacology 22 (1999) 108–124) and others, primary physiological mediators of somatic stress responses include glucocorticoids (cortisol), catecholamines (adrenaline and noradrenaline), and serum dihydroepiandosterone‐sulfate (DHEA‐S). Conversely, blood pressure (BP), serum HDL and total cholesterol, glycated hemoglobin (HbA1c), and waist/hip (w/h) ratio are modulated by such hormones, thereby acting as secondary mediators of stress response. When these risk factors are aggregated into a composite score, higher stress loads are associated with increased risks for days of school/work missed, functional losses, morbidity, and mortality in US samples. To examine stress loads in American Samoans, data on all 6 secondary mediators along with estimates of body habitus (i.e. height, weight, circumferences, skinfolds) and physiology (i.e. fasting insulin, LDLc, triglycerides, fasting glucose) were measured on 273 individuals residing on Tutuila Island in 1992. Four combinations of these physiological factors were used to determine composite estimates of stress. These were then assessed by sex for associations with age and the presence of diabetes. Composite estimates of stress load were higher in Samoan women than men. Associations with age tended to be low and negative in men, but positive in women, appearing to reflect cultural circumstances and population history. Stress load scores also were higher among those with diabetes than those without among both men and women. These results suggest that composite estimates of stress may be useful for assessing future risks of CDC's and the senescent processes that may underlie them in cross‐cultural research. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
Electrophilic Activation of Alkenes by Platinum(II): So Much More Than a Slow Version of Palladium(II)
Authors: Chianese Anthony R. , Lee Stephen J. , Gagné Michel R.
Published: May 2007

The electrophilic activation of alkenes by transition‐metal catalysts is a fundamental step in a rapidly growing number of catalytic processes. Although palladium is the best known metal for this purpose, the special properties of its third‐row cousin platinum (strong metal–ligand bonds and slow substitution kinetics) have enabled the development of transformations that are initiated by addition to the CC bonds by protic carbon, nitrogen, oxygen, and phosphorus nucleophiles, as well as alkene or arene nucleophiles. Additionally, reactivity profiles, which are often unique to platinum, provide wholly new reaction products. This Review concerns platinum‐catalyzed electrophilic alkene activation reactions, with a special emphasis on the mechanistic properties of known systems, on the differences between platinum and palladium catalysts, and on the prospects for the development of new systems.
Palm‐based bio‐composites hybridized with kaolinite
Authors: Mat Amin Khairul Anuar , Haji Badri Khairiah
Published: May 2007

This study described the mechanical and thermal properties of hybrid bio‐composites from oil palm empty fruit bunch (EFB) fibers and kaolinite. The polyurethane (PU) used as matrix is formed by reacting palm kernel oil (PKO)‐based polyester with crude isocyanate. The blending ratio of PU to EFB fibers was fixed at 35 : 65 and kaolinite was added at 0, 5, 10, 15, and 20% (by weight). The occurrence of chemical interactions between the hydroxyl terminals in both fillers and the PU system was determined via FTIR spectroscopy. Hybrid bio‐composites showed improved stiffness, strength, and better water resistance with the addition of kaolinite to an extent. At 15% of kaolinite loading, maximum flexural and impact strengths were observed. The interaction between kaolinite with PU matrix and EFB fibers enhanced the mechanical properties of the bio‐composites, which was justified from the FTIR spectrum. However, over‐packing of kaolinite was observed at 20% kaolinite loading, which ruptured the cellular walls and degraded strength of the bio‐composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Do information technology units have more power than other units in academic libraries?
Authors: Lim Sook
Published: May 2007

Systems offices that deal with library information technologies have played an important role in academic libraries; however, not much is known about how systems offices are positioned within academic libraries. This study examined the present status and the influence of systems offices by exploring the power differences among five principal functional units based on strategic contingencies theory. A mail questionnaire was sent to the principal functional unit heads of each of 95 university libraries belonging to the Association of Research Libraries in the United States. A total of 484 questionnaires were sent; 235 questionnaires were returned. The three major findings of this study were that (a) systems offices had more perceived power than all but public services; (b) systems offices had higher levels on contingency variables than did most of the other units; and finally, (c) criticality was a factor affecting perceived power between systems offices and most of the other units. The study findings imply that strategic contingencies theory may be partially applicable to library settings. Library staff or units may strategically increase their power by aligning their services with goals critical to their library and cooperating with other staff or other units.
User rankings of search engine results
Authors: Bar‐Ilan Judit , Keenoy Kevin , Yaari Eti , Levene Mark
Published: May 2007

In this study, we investigate the similarities and differences between rankings of search results by users and search engines. Sixty‐seven students took part in a 3‐week‐long experiment, during which they were asked to identify and rank the top 10 documents from the set of URLs that were retrieved by three major search engines (Google, MSN Search, and Yahoo!) for 12 selected queries. The URLs and accompanying snippets were displayed in random order, without disclosing which search engine(s) retrieved any specific URL for the query. We computed the similarity of the rankings of the users and search engines using four nonparametric correlation measures in [0,1] that complement each other. The findings show that the similarities between the users' choices and the rankings of the search engines are low. We examined the effects of the presentation order of the results, and of the thinking styles of the participants. Presentation order influences the rankings, but overall the results indicate that there is no “average user,” and even if the users have the same basic knowledge of a topic, they evaluate information in their own context, which is influenced by cognitive, affective, and physical factors. This is the first large‐scale experiment in which users were asked to rank the results of identical queries. The analysis of the experimental results demonstrates the potential for personalized search.
Magnetic fields generated by an induction heating (IH) cook top do not cause genotoxicity in vitro
Authors: Miyakoshi Junji , Horiuchi Emi , Nakahara Takehisa , Sakurai Tomonori
Published: May 2007

The use of induction heater (IH) cook tops in homes has become widespread, especially in Japan, but there are concerns about the safety of intermediate frequency (IF) electromagnetic fields associated with these cooking appliances. Since the cellular genotoxicity of IF magnetic fields has not been examined in cultured cells, we examined the effects of these fields at a magnetic flux density of 532 ± 20 μT at 23 kHz, using an exposure unit with a built‐in CO2 incubator. Exposure to the IF magnetic field at 532 µT for 2 h did not affect the growth of CHO‐K1 cells and caused no mutagenic effects in bacterial mutation assays. Exposure to the IF magnetic field for 2 h induced neither single nor double DNA strand breaks in comet assays, and caused no significant change in the mutation frequency at the HPRT locus compared to sham exposure. The magnetic field used in this study is more than 80 times higher than the level recommended as safe in the International Commission on Non‐ionizing Radiation Protection (ICNIRP) guidelines. From these results, we suggest that exposure to an IF magnetic field for 2 h does not cause cellular genotoxicity in bacteria and in Chinese hamster cells. However, the possibility of effects on other cellular functions remains, and further studies on the cellular effects of IF magnetic fields are required. Bioelectromagnetics 28:529–537, 2007. © 2007 Wiley‐Liss, Inc.
Synthesis and Heavy‐Metal‐Ion Sorption of Pure Sulfophenylenediamine Copolymer Nanoparticles with Intrinsic Conductivity and Stability
Authors: Lü Qiu‐Feng , Huang Mei‐Rong , Li Xin‐Gui
Published: May 2007

Novel copolymer nanoparticles were easily synthesized with a polymerization yield of 59.3 % by an oxidative precipitation polymerization of aniline (AN) and m‐sulfophenylenediamine (SP) in HCl without any external stabilizer. The polymerization yield, size, morphology, electroconductivity, solubility, solvatochromism, lead and mercury ion adsorbability of the HCl‐doped copolymer salt particles were studied by changing the AN/SP ratio. The AN/SP (80:20) copolymer particles are found to have the minimal number‐average diameter(84.4 nm), minimal size polydispersity index (1.149), high stability, good long‐term stability, powerful redispersibility in water, high purity, and clean surface because of a complete elimination of the contamination from external stabilizer. The copolymer salts possess a remarkably enhanced solubility, interesting solvatochromism, and widely adjustable electroconductivity moving across nine orders of magnitudes from 10−9 to 100 S cm−1. The AN/SP (70:30) copolymer particles have the highest Hg2+ adsorbance and adsorptivity of 497.7 mg g−1 and 98.8 %, respectively, which are much higher values than those of other materials. The sorption mechanism of lead and mercury ions on the particles is proposed. The copolymer bases with 5–10 mol % SP unit show excellent film formability, flexibility, and smooth appearance. The copolymer should be very useful in the fabrication of cost‐effective conductive nanocomposite with low percolation threshold and in removal of toxic metallic ions from waste water.
Computational Investigations on the General Reaction Profile and Diastereoselectivity in Sulfur Ylide Promoted Aziridination
Authors: Janardanan Deepa , Sunoj Raghavan B.
Published: May 2007

Mechanism and diastereoselectivity of sulfur ylide promoted aziridination reactions were studied by density functional theory with inclusion of solvent effects through the continuum solvation model. The general reaction pathway was modeled for the addition of substituted sulfur ylides (Me2S+CH−R) to an aldimine ((E)‐methyl ethylidenecarbamate, MeHCNCO2Me). The nature of the substituents on the ylidic carbon atom substantially affects the reaction profile. The stabilized (R=COMe) and semistabilized (R=Ph) ylides follow a cisoid addition mode leading to trans aziridines via anti betaine intermediates. The simplest model ylide (unstabilized, R=H) underwent cisoid addition in a similar fashion. In the case of stabilized ylides product diastereoselectivity is controlled by the barriers of the elimination step leading to the 2,3‐trans aziridine, whereas it is decided in the addition step in the case of semistabilized ylides. The importance of steric and electronic factors in diastereoselective addition (2 and 5) and elimination (5) transition states was established. Comparison of results obtained with the gas‐phase optimized geometries and with the fully optimized solvent‐phase geometries reveals that the inclusion of solvent effects does not bring about any dramatic changes in the reaction profiles for all three kinds of ylides. In particular, diastereoselectivity for both kinds of ylides was found to be nearly the same in both these approaches.
A New Route for the Synthesis of NdB6 Powder from Nd2O3—B4C System.
Authors: Liu Y. , Lu W. J. , Qin J. N. , Zhang D.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis, Structure and Photochromic Properties of a Novel 1,6‐Hexanediamine Trimolybdate Supramolecular Compound.
Authors: Sun Dehui , Zhang Hongjie , Zhang Jilin , Zheng Guoli , Yu Jiangbo , Gao Shuyan
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Rapid Flux‐Assisted Synthetic Approach Towards the Bandgap Engineering of Layered Perovskites.
Authors: Porob Digamber G. , Maggard Paul A.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
The Ag2O—V2O5—HF(aq) System and Crystal Structure of α‐Ag3VO4.
Authors: Albrecht Thomas A. , Stern Charlotte L. , Poeppelmeier Kenneth R.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Diastereoselective Horner—Wadsworth—Emmons Reaction for the Synthesis of Tetrasubstituted Alkenes with an Axis of Chirality.
Authors: Sano Shigeki , Abe Shinobu , Azetsu Tomohiro , Nakao Michiyasu , Shiro Motoo , Nagao Yoshimitsu
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Enantioselective Organocatalysis of Strecker and Mannich Reactions Based on Carbohydrates.
Authors: Becker Christian , Hoben Christine , Kunz Horst
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Stereoselectivity of the Wittig Reaction in Two‐Phase System.
Authors: Al Busafi Saleh , Al Rawahi Waffa
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
3/4‐Phenylene Bisheterocycles from Ring Transformation Reaction of Sydnone Derivatives: Synthesis of 3‐[3/4‐Heterocyclyl]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones from 3/4‐Acetylphenylsydnones and Their Biological Properties.
Authors: Kamble Ravindra R. , Latthe Prashant R. , Badami Bharati V.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Recyclable Polymer‐Bound Pd(0) Phosphine Catalyst for Effecting sp2‐sp2 and sp2‐sp Carbon—Carbon Coupling Reactions in Aqueous Medium.
Authors: Koshti Nirmal , Parab Bharat , Naik Shubhangi
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
HClO4—SiO2 Catalyzed Multicomponent Reactions for the Synthesis of Privileged Heterocyclic Structures.
Authors: Mandal Pintu Kumar , Misra Anup Kumar
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Strained Azetidinium Ylides: New Reagents for Cyclopropanation.
Authors: Couty Francois , David Olivier , Larmanjat Benedicte , Marrot Jerome
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.