bluuebunny/crossref_metadata_2025 huggingface dataset:
Meta-Analysis: Pesticides and Orofacial Clefts
Authors: Romitti Paul A. , Herring Anna M. , Dennis Leslie K. , Wong-Gibbons Donna L.
Published: July 2007

Objective:

The risk of orofacial clefts associated with pesticide exposure was examined by conducting a meta-analysis of studies published from 1966 through 2005.

Design:

The full text of 230 studies was reviewed in detail, and of these, 19 studies were included in the final analysis. Fixed effects and random effects models were used to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs), and homogeneity among studies was evaluated.

Main outcome measures:

Exposure- and phenotype-specific risks associated with pesticides.

Results:

Many of the studies identified as suitable for analysis used a retrospective design with varying sample sizes, levels of exposure assessment, and phenotype evaluation. For all phenotypes combined, maternal occupational exposure was associated with an increased risk of clefting (OR = 1.37; CI = 1.04 to 1.81), whereas the estimates were somewhat weaker for paternal occupational exposures (OR = 1.16; CI = 0.94 to 1.44) or for any residential exposure (OR = 0.77; CI = 0.20 to 2.96). Calculation of pooled estimates for individual cleft phenotypes was mostly limited to studies of paternal occupational exposure; estimates exceeded unity but were not statistically significant.

Conclusions:

The results of this meta-analysis suggest that maternal exposure to pesticides is associated with a modest but marginally significant risk of clefting. To better understand the relationship between pesticide exposure and orofacial clefts, future studies should consider evaluation of multiple routes of parental exposure, etiologically homogenous phenotypes, and individual genetic susceptibility.
Three-Dimensional Computer Reconstruction of the Levator Veli Palatini Muscle in Situ Using Magnetic Resonance Imaging
Authors: Perry Jamie L. , Kuehn David P.
Published: July 2007

Objective:

Most studies have used two-dimensional (2D) data to image and study the velopharyngeal mechanism, oversimplifying the complexity of the system. Three-dimensional (3D) computer modeling and animation offers the advantage of viewing in all coordinate planes and gives the researcher the ability to apply external forces and chart resultant movement patterns. The objective of this project was to create a 3D model of the velopharyngeal mechanism, with primary focus on the levator veli palatini muscle, based on magnetic resonance imaging (MRI) data to demonstrate the velum at rest and during elevation.

Method:

Quantitative data, based on MRI analyses and consisting of levator muscle length, width, and orientation were modeled using the Maya software system.

Results:

Using data derived from MRI analyses, an accurate and realistic computer reconstruction of the levator muscle in situ was possible. A video of the animation was created to demonstrate the anatomy from variable view points, layering of the velar muscles, and movement of the velopharyngeal mechanism during vowel production.

Conclusion:

Improvements in visualization of the levator veli palatini muscle through 3D computer graphics offer a promising future for the field of speech science in providing advancements in basic research. It will be valuable in applied research and clinical activities such as surgical management for individuals impacted by a cleft palate. It is a step forward in creating models of abnormal anatomy (i.e., cleft palate) and is a step closer to a virtual surgical planning tool.
Facial Symmetry in Unilateral Cleft Lip and Palate following Alar Base Augmentation with Bone Graft: A Three-Dimensional Assessment
Authors: Devlin Mark F. , Ray Arup , Raine Peter , Bowman Adrian , Ayoub Ashraf F.
Published: July 2007

Objective:

The aim of this study was to assess the outcome of bone grafting using a corticocancellous block of iliac crest to reconstruct the support for the deformed, volume-deficient alar base in treated patients with unilateral cleft lip and palate (UCLP). The main outcome being measured was nasal symmetry.

Design:

This was a prospective study using a noninvasive three-dimensional stereophotogrammetry system (C3D) to assess the position of the alar base. Images were captured immediately preoperatively and at 6 months following the augmentation of the alar base with a block of bone graft. These images were used to calculate facial symmetry scores and were compared using a two sample Student's t test to assess the efficacy of the surgical method in reducing facial/nasal asymmetry.

Patients:

This investigation was conducted on 18 patients with one patient failing to attend for follow-up. The results for 17 patients are presented.

Results:

Facial symmetry scores improved significantly following the insertion of the bone graft at the deficient alar base (p = 0.005).

Conclusions:

3D stereophotogrammetry is a noninvasive, accurate, and archiveable method of assessing facial form and surgical change. Nasal symmetry can be quantified and measured reliably with this tool. Bone grafting to the alar base region of treated UCLP patients with volume deficiency produces improvement in nasal symmetry.
Construction methods with geotextiles
Authors: Whyley P. J.
Published: July 2007

In any branch of engineering, consideration of construction methods is an essential part of the design process. This is particularly true for designs which incorporate geotextiles.

There are many factors influencing fabric survivability including construction equipment and technique, formation material and condition, fill or cover material type, and environmental factors. This Technical Note covers the aspects of supply, storage, handling, ground preparation, laying, jointing, anchoring, covering and compacting where they influence the overall design of a geotextile as a separating layer. The note provides guidance on the preparation of specifications to ensure that the designed use of the geotextile is actually achieved, at the same time showing the constraints in which contractors have to plan their construction works.
An investigation into the potential use of solid snow barriers on the Snake Pass, Derbyshire
Authors: Baker C. J. , Dutch W. G.
Published: July 2007

The northern areas of the Peak District National Park, notably in Derbyshire, are prone to high snow falls and associated snow drifting problems. To mitigate the effect of snow drifting on highways a system of temporary wooden snow fences has often been employed. A permanent variation on this approach became possible during the design of a major road improvement on the Snake Pass, Derbyshire. At the time of the scheme construction in 1986 no research had been conducted on the effectiveness of solid (rock bunds) barriers. Further to this, the most effective height and shape of the barrier for snow collection were unknown as was the critical distance from the highway boundary to prevent snow drifts from encroaching on the highway. This Paper describes the results of wind tunnel experiments which were conducted at Nottingham University to provide guidance and recommendations on the shape, lengths and efficiency of various solid (rock) barriers. It was found that solid barriers are an effective method of containing wind-borne snowin drifts and that in this test they were two to three times more efficient (in terms of volume of snow collected) than the standard (50%) porous wooden fence.
Pedestrian flow data collection and analysis
Authors: Cunningham P. P. , Cullen D. A.
Published: July 2007

Although considerable work has been undertaken in the past to establish the principles of pedestrian flow, it has been the personal computer and the hand-held data logger than have enabled modelling of the pedestrian movement to be undertaken. Hitherto, most work had concentrated on what might be called the ‘street scene’. London Underground Limited wanted to extend and modify, where appropriate, the understanding of pedestrian behaviour. This would enable them to build computer models that reflected more accurately the behaviour of pedestrians within their rail stations.

Before modelling could be undertaken, a series of surveys had to be carried out in order to establish the relationships between flow and journey times on various facilities encountered within stations-passageways, platforms, stairs, escalators and concourses. Subsequently, while modelling station changes that would improve passenger safety and amenities, observations were made of a variety of factors required by the model: train loadings, platform congestion, service regularity and reliability, in addition to volumetric counts and journey times on foot within the station.

This Paper describes the background to the London Underground studies, and the work that had to be undertaken to help form an understanding of pedestrian behaviour within stations. It then describes the data collection and analysis aspects, including factors such as the training of enumerators for the tasks. It also discusses the requirement to model a base day, and the procedures adopted in order to produce a statement of annual worth of a scheme from a modelled base day.
A review of people mover systems and their potential role in cities
Authors: North B. H.
Published: July 2007

People mover systems have been described as ‘Guided transit systems specifically designed to carry large numbers of people short distances at frequent regular intervals’. Passenger conveyors, moving pavements, travelators, people mover systems all meet the above definition and have been the dreams of inventors since 1859. Britain's first moving pavement was successfully used at the 1924 Wembley Exhibition.

These systems have often been developed specifically for exhibitions. Since then dozens of systems have been designed but very few have been used other than at their initial sites. Even the innovative Maglev system at Birmingham Airport has never been developed, nor used elsewhere.

Nevertheless some systems have become well established and new ones developed. There are currently over twenty different systems in operation worldwide, mainly at airports. New systems are being developed all the time and they are becoming more versatile.

This Paper reviews the state of the art of these systems including their individual features, capabilities and capacities, followed by an assessment of developments and of their future role.
Developments in the analysis, testing and damage assessment of railway bridges
Authors: Lemmon C. , Woolfenden P. A.
Published: July 2007

Computer finite-element methods form the basis of a new technique for representing the structural complexity of an arch bridge, as a basis for assessing bridge condition. Masonry arch finite-element assessment (MAFEA), physical testing and assessment of structures, and bridge cost and damage assessment systems, are described in detail
Incorporating elasto-plasticity in granular layer pavement design
Authors: Wolff H. , Visser A. T.
Published: July 2007

Full-scale heavy vehicle simulator (HVS) testing of pavements incorporating granular layers indicated that granular materials behave elasto-plastically when subjected to repeated traffic loading. Elasto-plastic behaviour implies that permanent deformation takes place with every load repetition, although traffic loading normally induces stresses well below the failure stress of the material as defined bythe Mohr–Coulomb failure envelope. In the development of design a method for granular layers, cognizance should therefore be taken of the permanent deformation that occurs with each load repetition. In this Paper, the development ofa design method for limiting rutting granular layers developed from data obtained through full-scale HVS testing and using the principle of S–N curves, is described. HVS data indicated that the model generally used to describe the relation between permanent strain development and number of load repetitions does not give reliable estimates of the permanent deformation at large numbers of load repetitions. The design method described here recognizes the elasto-plastic behaviour of granular materials and uses an improved model to describe the relation between permanent deformation development and number of load repetitions. This design method was found to give reasonable predictions of the loading capacity of in-service low volume roads comprising mainly granular layers
M40 Oxford–Birmingham: geology and geotechnics of the Waterstock–Banbury section
Authors: Nicholls R. A.
Published: July 2007

This Paper discusses the route geology of the Waterstock–Banbury section of the M40 Oxford–Birmingham motorway. A desk study by Ove Arup and Partners in 1973 was followed by various site investigations between 1978-1983. These established design parameters and the nature of the material encountered. The geological units are reviewed in descending stratigraphical order. Consideration of the geology along the route indicated that some sections with specific geotechnical problems were to be expected.
Expansion of Manchester Airport
Authors: Congdon L. , Taylor A. , Lambert R. C. , Custance M. , Wilbraham D. L. , Cottell M N. T. , Burgess G.
Published: July 2007

It is very interesting to see the growing interest and support of the Government, that perhaps did not exist in years gone by, for a regional airport to be able to satisfy its local demand. One of the problems in London is that millions of the catchment population move down to London to take flights that currently cannot be taken from the local regional airports. This project is, I think, a significant regional development that will be more convenient for both business and pleasure in the future.
Prediction of Periodontal Disease From Multiple Self‐Reported Items in a German Practice‐Based Sample
Authors: Dietrich T. , Stosch U. , Dietrich D. , Kaiser W. , Bernimoulin J.‐P. , Joshipura K.
Published: July 2007

Background: Ascertainment of periodontal disease using self‐reported measures would be useful for large epidemiologic studies. This study evaluates whether a combination of self‐reported items with established risk factors in a predictive model can assess periodontal disease accurately.

Methods: Responses of 246 subjects to a detailed questionnaire were compared to their periodontal disease history as assessed from radiographs. Multiple regression modeling was used to construct predictive models using self‐reported items and established risk factors.

Results: Depending on the definition of gold‐standard periodontal disease, two or three self‐reported items were selected for the predictive models, in addition to age, gender, and smoking. Self‐reported tooth mobility was associated strongly with periodontal disease independent of other risk factors and was selected in all models. For dichotomous definitions of periodontal disease, discrimination of predictive logistic regression models was good with areas under the receiver operating characteristic curve >0.80. Assessment of periodontal disease history based on extreme quantiles of model‐predicted values yielded high sensitivity and specificity.

Conclusion: The combination of several self‐reported items may be useful for ascertainment of periodontal disease in epidemiologic studies.
Acellular Dermal Matrix as a Membrane for Guided Tissue Regeneration in the Treatment of Class II Furcation Lesions: A Histometric and Clinical Study in Dogs
Authors: de Andrade Patrícia Freitas , de Souza Sérgio Luís Scombatti , de Oliveira Macedo Guilherme , Novaes Arthur Belém , de Moraes Grisi Márcio Fernando , Taba Mário , Palioto Daniela Bazan
Published: July 2007

Background: The purpose of this study was to evaluate acellular dermal matrix (ADM) as a membrane for guided tissue regeneration (GTR) in the treatment of mandibular Class II furcation lesions and to compare it to a bioabsorbable membrane.

Methods: Class II furcation lesions were created surgically and chronified in six mongrel dogs on the buccal surfaces of mandibular third and fourth premolars, bilaterally. After 1 month, GTR was performed. Each side was assigned randomly to the control group (CGr: bioabsorbable membrane made of polyglycolic acid: trimethylene carbonate) or the test group (TGr: ADM as a membrane). Clinical measurements of the width and thickness of the keratinized tissue (WKT and TKT, respectively) were made before GTR. The dogs were sacrificed 12 weeks following GTR, and histomorphometric analysis was performed. Area measurements were taken of new tissue, epithelium, connective tissue, and new bone; bone height and new cementum were measured.

Results: The formation of new bone, cementum, and periodontal ligament were similar in both groups. There were no statistically significant differences between the groups for any histomorphometric measurement. The TGr had a statistically significant increase in WKT and TKT after 3 months. The mean TKT gain was 1.03 mm for the TGr and 0.26 mm for the CGr (P <0.05).

Conclusion: The ADM demonstrated histomorphometric results similar to the bioabsorbable membrane and resulted in a greater increase in the thickness of the keratinized tissue.
Comparison of Two Surgical Procedures for Use of the Acellular Dermal Matrix Graft in the Treatment of Gingival Recessions: A Randomized Controlled Clinical Study
Authors: Felipe Maria Emília M.C. , Andrade Patrícia F. , Grisi Marcio F.M. , Souza Sérgio L.S. , Taba Mário , Palioto Daniela B. , Novaes Arthur B.
Published: July 2007

Background: The aim of this randomized, controlled, clinical investigation was to compare two surgical techniques for root coverage with the acellular dermal matrix graft to evaluate which technique provided better root coverage, a better esthetic result, and less postoperative discomfort.

Methods: Fifteen patients with bilateral Miller Class I or II gingival recessions were selected. Fifteen pairs of recessions were treated and assigned randomly to the test group, and the contralateral recessions were assigned to the control group. The control group was treated with a broader flap and vertical releasing incisions; the test group was treated with the proposed surgical technique, without vertical releasing incisions. The clinical parameters evaluated were probing depth, relative clinical attachment level, gingival recession (GR), width of keratinized tissue, thickness of keratinized tissue, esthetic result, and pain evaluation. The measurements were taken before the surgeries and after 6 months.

Results: At baseline, all parameters were similar for both groups. At 6 months, a statistically significant greater reduction in GR favored the control group. The percentage of root coverage was 68.98% and 84.81% for the test and control groups, respectively. The esthetic result was equivalent between the groups, and all patients tolerated both procedures well.

Conclusions: Both techniques provided significant root coverage, good esthetic results, and similar levels of postoperative discomfort. However, the control technique had statistically significantly better results for root coverage of localized gingival recessions.
Dental Implants for Immediate Fixed Restoration of Partially Edentulous Patients: A 1‐Year Prospective Pilot Clinical Trial in Periodontally Susceptible Patients
Authors: Machtei Eli E. , Frankenthal Shai , Blumenfeld Israel , Gutmacher Zvi , Horwitz Jacob
Published: July 2007

Background: The aim of this study was to evaluate the survival of dental implants in periodontally susceptible patients using immediate loading/restoration (ILR) protocols and the factors that modulate this response.

Methods: Systemically healthy patients who were treated previously for chronic periodontitis and who required implant therapy were recruited. Following data collection, “surgical templates” and provisional fixed restorations were fabricated. Transgingival implants were inserted, and surgical measurements were performed. After abutment connection, the crown/bridge was relined and cemented. Patients were monitored for 12 months, at which time final measurements were performed.

Results: Twenty patients (49 implants) completed this study; five implants failed and were removed (90% survival rate). All implants were removed during the first 6 months. At 12 months, the mean implants' probing depth was 2.87 ± 0.9 mm. The mean electronic mobility testing device value (−1.3 ± 0.7) was slightly higher than at baseline (−3.53 ± 10.7). Radiographic bone loss ranged between −1.24 and 2.77 mm (mean ± SD: 0.91 ± 0.2 mm). All of the implants (16) that were inserted in the premolar region were successful, whereas three of nine implants in the molar region and two of 24 implants in the canine/incisor region failed (P = 0.0278). Survival in the immediately loaded group (83%) was slightly lower than in the immediately restored group (96%); however, these differences did not reach statistical significance. None of the other variables (smoking, arch, stability, implant length and diameter, and bone width) affected the outcome of this procedure.

Conclusions: ILR protocols are predictable alternatives in periodontally susceptible patients. Results in the molar regions suggested that careful consideration should be given to implants placed in these sites. Long‐term success in these patients has not been addressed.
Self‐Reported Periodontal Disease: Validation in an Epidemiological Survey
Authors: Taylor George W. , Borgnakke Wenche S.
Published: July 2007

Background: Evidence is accumulating to support poor oral health as a risk factor for systemic conditions, including cardiovascular diseases, diabetes control, adverse pregnancy outcomes, and pneumonia. Prohibitive costs for clinical assessment of periodontal disease limit information to assess the prevalence and trends of periodontal diseases in the United States population. However, self‐report is used widely to assess economically the population‐based prevalence of various medical conditions and health‐related behaviors and characteristics.

Methods: The goal of this secondary data analysis was to identify self‐report items sufficiently correlated with clinical periodontal disease for use via face‐to‐face or telephone interviews. Data for analysis were collected for a project focused on oral health that included face‐to‐face interview items regarding oral health‐related self‐care, professional care, and barriers; knowledge, beliefs, and attitudes; risk behavior; impact on quality of life; and demographic characteristics. Also, participants had complete oral examinations.

Results: Logistic regression analyses identified self‐reported items contributing to two sets of models predicting moderate or severe periodontal disease (MODSEV) and severe periodontal disease (SEV). Age, gender, race/ethnicity, smoking, and periodontal health‐related self‐report items constituted predictive models with maximum sensitivity and specificity of 71% and 83%, respectively, with area under the receiver operating characteristic curve (AUC) of 0.85 (as a measure of accuracy) for MODSEV. For SEV, predictive models' maximum sensitivity and specificity were 92% and 53%, respectively, with a maximum AUC of 0.92.

Conclusion: These analyses suggest that self‐report may be valid for surveillance of periodontal disease burden and trends in the American population, in lieu of more costly clinical periodontal examinations.
Triple Immediate Therapy (ridge expansion, soft tissue augmentation, and provisional restoration) of Maxillary Anterior Single Implant
Authors: Lai Yu‐Lin , Chou I‐Chiang , Liaw Yu‐Cheng , Chen Hen‐Li , Lin Yi‐Chun , Lee Shyh‐Yuan
Published: July 2007

Background: Immediate restoration during implant placement in the premaxillary area can achieve a favorable esthetic result. However, the treatment always poses a great challenge to clinicians, especially for patients with preexisting soft and hard tissue deficiencies. The aim of this clinical report was to present a protocol for a multidisciplinary approach to provide an immediate implant restoration for patients with ridge deficiency.

Methods: A 21‐year‐old female presented with a mesial shift of the maxillary right canine due to loss of a lateral incisor at an early age. The treatment protocol included orthodontic space redistribution to open a canine space for implant placement. Subsequently, ridge expansion and implant placement combined with connective tissue grafting for the reconstruction of the soft tissue profile were performed, and an immediate provisional prosthesis was delivered simultaneously. A definitive University of California at Los Angeles–style ceramometal crown was completed 6 months later with periodical clinical maintenance.

Results: The 18‐month postoperative follow‐up revealed that the implant was stable, and the buccal depression of the surgical area was reconstructed. Papillae were augmented, and a harmonious soft tissue margin was achieved in the esthetic zone. Radiographs demonstrated a normal vertical osseous height and excellent osseointegration of the implant.

Conclusions: The combination technique of ridge expansion and soft tissue augmentation can be applied to immediate implant restoration cases without the need for complicated bone grafting surgeries in atrophic ridges. This triple immediate strategy enabled us to reduce the number of surgeries, which simplified the overall procedure without compromising the esthetic results.
Renal Function and Periodontal Disease in Elderly Japanese
Authors: Yoshihara Akihiro , Deguchi Tomoya , Hanada Nobuhiro , Miyazaki Hideo
Published: July 2007

Background: Chronic renal failure involves a slow, progressive loss of renal function over months or years. It is possible that periodontal disease and chronic kidney disease might share common risk factors. This study investigated whether a link exists between periodontal disease and chronic renal function in community‐dwelling elderly subjects.

Methods: A total of 14‐ study subjects, all 77 years of age, participated in this study. A periodontal examination was carried out by trained dentists. Urine was collected over 24 hours, and blood was taken on the morning of the dental exam. The volume of creatinine per 24 hours (Cre_U) and volume of urine per 24 hours were used as urinary markers of kidney function; serum creatinine levels (Cre_S) were used as a blood marker of kidney function. Creatinine clearance per 24 hours was calculated as Cre_U/Cre_S. In addition, biochemical parameters of bone turnover were measured: urinary deoxypyridinoline (U‐DPD) as a bone resorption marker and serum osteocalcin (S‐OC) as a bone formation marker. Multiple regression analysis was used to evaluate the relationship between the percentage of periodontal sites with ≥6‐mm clinical attachment level (% ≥6‐mm CAL) and renal function, as well as the relationship between % ≥6‐mm CAL and bone metabolism. The % ≥6‐mm CAL was used as the dependent variable. The number of remaining teeth, smoking habit, gender, use of interdental brushes or dental floss, volume of urine per 24 hours, and creatinine clearance per 24 hours were independent variables in the first test. In addition, the number of remaining teeth, smoking habits, gender, use of interdental brushes or dental floss, U‐DPD, and S‐OC were independent variables in the second test.

Results: Multiple regression analysis showed that creatinine clearance per 24 hours and S‐OC were significantly associated with % ≥6‐mm CAL per person. The standardized coefficients were 0.26 (P = 0.015) and −0.27 (P = 0.006), respectively.

Conclusions: The % ≥6‐mm CAL was significantly associated with renal function and bone metabolism markers. This study suggests that the increased incidence of chronic renal failure that occurs with age might increase the probability of severe periodontal disease in community‐dwelling elderly subjects.
RANKL Inhibition Through Osteoprotegerin Blocks Bone Loss in Experimental Periodontitis
Authors: Jin Qiming , Cirelli Joni A. , Park Chan Ho , Sugai James V. , Taba Mario , Kostenuik Paul J. , Giannobile William V.
Published: July 2007

Background: Prevention of alveolar bone destruction is a clinical challenge in periodontal disease treatment. The receptor activator of nuclear factor‐kappa B ligand (RANKL) inhibitor osteoprotegerin (OPG) inhibits osteoclastogenesis and suppresses bone resorption.

Methods: To study the effects of RANKL inhibition on alveolar bone loss, an experimental ligature‐induced model of periodontitis was used. A total of 32 rats were administered human OPG‐Fc fusion protein (10 mg/kg) or vehicle by subcutaneous delivery twice weekly for 6 weeks. Negative or positive controls received no treatment or disease through vehicle delivery, respectively. Biopsies were harvested after 3 and 6 weeks, and mandibulae were evaluated by microcomputed tomography (μCT) and histology. Serum levels of human OPG‐Fc and tartrate‐resistant acid phosphatase‐‐b (TRAP‐5b) were measured throughout the study by enzyme‐linked immunosorbent assay (ELISA). Statistical analyses included analysis of variance (ANOVA) and Tukey tests.

Results: Human OPG‐Fc was detected in the sera of OPG‐Fc–treated animals by 3 days and throughout the study. Serum TRAP‐‐b was sharply decreased by OPG‐Fc treatment soon after OPG‐Fc delivery and remained low for the observation period. Significant preservation of alveolar bone volume was observed among OPG‐Fc–treated animals compared to the controls at weeks 3 and 6 (P <0.05). Descriptive histology revealed that OPG‐Fc significantly suppressed osteoclast surface area at the alveolar crest.

Conclusion: Systemic delivery of OPG‐Fc inhibits alveolar bone resorption in experimental periodontitis, suggesting that RANKL inhibition may represent an important therapeutic strategy for the prevention of progressive alveolar bone loss.
Morphotypes, polymorphism and peristome in the species of the genus Holcophylloceras Spath, 1927. Hypothesis of the dimorphism in the species Holcophylloceras zignodianum (d’Orbigny, 1848)
Authors: Joly Bernard , Fonters Bruno
Published: July 2007

The genus Holcophylloceras Spath, 1927, including especially a majority of Jurassic species and some rare lower Cretaceous species, is easy to distinguish from other genera with constrictions such as Calliphylloceras Spath, 1927 or Sowerbyceras Parona & Bonarelli, 1895. In the genus Holcophylloceras the constrictions are clearly sigmoid or falcoid. Both characteristics can be observed on the same specimen. In the genus Calliphylloceras the constrictions are falcoid while they are sigmoid on Sowerbyceras. Actually these genera are closely allied and they represent evolutionary stages in a lineage characterized by more or less growth alteration. The lineage origin probably exists among Liassic Phylloceras. The genus Calliphylloceras shows a small growth alteration, while it is maximal in Sowerbyceras and it is intermediate in Holcophylloceras.

This note shows that species of the genus Holcophylloceras are also characterized by three morphotypes: prae-caucasica, caucasica and nausikaae; these morphotypes do not characterize any particular species. The first and the second morphotypes could be an adaptation to live in deep waters. They probably give more solidity to the shell. The initial object of this note was to study again all the morphotypes of the genus Holcophylloceras with a new material collected in the oxfordian “Terres noires”.

The authors of this note have studied the relations between the morphotypes prae-caucasica, caucasica and the peristome of Holcophylloceras. Does the peristome study permit to envisage the existence of dimorphic couples? (sexual dimorphism?). The result has been disappointing. On the other hand many microconchs and macroconchs have been identified. In particular with zignodianum-mediterraneum it is possible to identify the “male form” (zignodianum = microconch) and the “female form” (mediterraneum = macroconch) which confirms the intuition of Beznosov [1958] by an other approach to the problem. Many authors asked them if they had to separate the forms with sigmoid constrictions from those with falcoid constrictions. It seems now, there is no doubt and both species zignodianum-mediterraneum have to be joined in the same taxon zignodianum which has priority over mediterraneum.

Last result of this study is the justification of the genus Holcophylloceras created by Spath.
Mirror and Camera Self-Focusing Effects on Complexity of Private and Public Aspects of Identity
Authors: Davies Martin F.
Published: July 2007

Complexity of private and public aspects of identity was investigated as a function of mirror and camera self-focusing. Using a sorting task to assess self-complexity, complexity of private but not public aspects of identity was greater under mirror self-focusing than under camera or no self-focusing, and complexity of public but not private aspects of identity was greater under camera self-focusing than under mirror or no self-focusing. The findings complement and extend previous research on the articulation of self-schemas as a function of self-focusing and self-consciousness.
Molecular structure and shear rheology of long chain branched polypropylene formed by light cross‐linking of a linear precursor with 1,3‐benzenedisulfonyl azide
Authors: Jørgensen Jens Kjær , Redford Keith , Ommundsen Espen , Stori Aage
Published: July 2007

Linear isotactic metallocene based polypropylene (Mw = 125,000 g/mol, Mn = 61,000 g/mol) was lightly crosslinked by small amounts of 1,3‐benzenedisulfonyl azide to form long chain branches (LCB). Crosslinking was carried out by reactive extrusion at 200°C in a small scale extruder. At the processing temperature, the two azide groups decompose to nitrenes that work as crosslinkers for PP. The crosslinking reaction occurs primarily by insertion of singlet nitrenes into CH bonds. 1,3‐benzenedisulfonyl azide concentrations of, respectively, 518, 806, 1029, and 2038 ppm were used. SEC revealed formation of a high molecular weight LCB fraction. No degradation was observed by SEC. The introduction of LCB gave rise to rheological behavior typical of LCB as increased zero shear viscosity, accompanied by increased shear thinning, increased flow activation energy and a phase angle plateau. However, the rheological impact and crosslinking efficiency observed were limited compared to earlier studies on PE. Possible reasons for this are discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Enantioselective Catalysis, XIII. Preparative and Structural Chemistry of Chiral 3‐(Diphenylphosphanyl)‐pyrrolidiens and Their Palladium(II) Complexes
Authors: Nagel Ulrich , Nedden Hans Günter
Published: July 2007

The preparation of both enantiomers of 3‐diphenylphosphanulpyrrolidiine (2) and several N‐substituted derivatives together with two PdIi complexes of this ligand is reported. Form L‐malic acid and L‐hydroxyproline both enantiomers of 3‐hydroxypyrrolidine are prepared without any problems due to epimerization. KPPh2 in the presence of LiCl is shown to be the most effective reagent for the synthesis of 2. The reported X‐ray structure determination sof Pdl2 complexes show a rather rigid bicyclic hetero‐norbornane skeleton. The flexibility of the other parts of the molecules is obvious in several polymorphs revealed by this method. This polymorphism is additionally investigated by a 31P‐CP‐MAS study. From solution 1‐, 13C‐ and 31P‐NMR studies it is concluded that the bicyclic hetero‐norbornane skeleton is retained in solution.
Atropisomeric Binaphthalene‐Core Phosphacyclic Derivatives in Coordination Chemistry and Homogeneous Catalysis
Authors: Gladiali Serafino , Fabbri Davide
Published: July 2007

Binaphthophospholes and binaphthophosphepines have recently been synthesized. These are the first representatives of a new class of chiral ligands that include within the same structure an endocyclic phosphorus donor, a local C2 symmetry and an axially chiral core. In this review we discuss the synthesis, chemical behaviour and first applications in asymmetric catalysis of these novel derivatives.
Well‐Defined Metallodendrimers by Site‐Specific Complexation
Authors: Bosman Anton W. , Schenning Albert P. H. J. , Janssen René A. J. , Meijer E. W.
Published: July 2007

Strong multiple complexation of transition metal ions, Cu(II), Zn(II) and Ni(II) with different generations of well‐defined poly(propylene imine) dendrimers as multi(tridentate) ligands has been used to construct nanoscopic assemblies of defined structure and size incorporating a distinct number of metal ions from 2 up to 32.
Synthesis of Germatranyl Derivatives of Esters of Carboxylic Acids via Organometallic (Si, Ge, Sn) Reagents
Authors: Zaitseva Galina S. , Livantsova Ljudmila I. , Nasim Mohammed , Karlov Sergei S. , Churakov Andrei V. , Howard Judith A. K. , Avtomonov Evgeni V. , Lorbert Jörg
Published: July 2007

Trialkylstannyl esters of tris(2‐hydroxyalkyl)amines, N(CH2CHROSnAlk3)3 (9‐11 (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(R2)COOR3 (12–17) (X  Cl or Br; R1, R2=H, Me, Ph, SiMe3, COOEt; R3=Me, Et) to give esters of α‐germatranylcarboxylic acids, N(CH2CHRO)3GeC(R1)(R2)‐COOR3 (1–8), in high yields. The synthesis of esters 12–17 is reported. Esters of α‐germatranyldiphenylacetic acid 24 and 25 can be obtained by treatment of diphenylketene with Et3SnOMe to give in situ Et3SnC(Ph2)COOMe (23), followed by reaction with GeCl4 to give in situ Cl3GeC(Ph2)COOMe (22 and further reactions with 9 or 11, respectively. Reduction of germatrane 6 with LiAlH4 in diethyl ether leads to cleavage of the germanium‐carbon bond with subsequent formation of (2‐hydroxyethyl)trimethylsilane. The crystal structures of 3, 6 and 7 are reported. 1‐Acyloxygermatranes 26 and 27 are obtained by treatment of 1‐methoxygermatrane (28) with diphenyl‐ and dichloroacetic acid, respectively.
Sulfur Compounds, 199. Novel Titanocene Thiolato Complexes and Their Application in Preparing New Sulfur‐Containing Heterocycles
Authors: Steudel Ralf , Kustos Monika , Münchow Vera , Westphal Ursula
Published: July 2007

Treatment of Cp2Ti(CO)2 (3) with the di‐ and polysulfanes 1,2,4‐(CH2)2S3, C4S6 (9), C,7H10S3 (11), 1,2,4,6‐(CH2)3S4 (16), C6H10S6(19), and S6 affords the titanocene chelate complexes Cp2TiS3(CH2)2 (8), (Cp2Ti)2C4S6 (10), Cp2TiS3C7H10 (13), Cp2TiS2C7H10 (14), Cp2TiS4(CH2)3 (17), Cp,2TiS6C6H6H10 (20), and Cp2TiS8 (23). 14 is also obtained from Cp2TiCl2 (1) and the geminal dithiol of norbornene. The analogous reaction with the dithiol of dicyclopentadiene yields Cp2TiS2C10H12 (15). In ligand transfer reactions, 8 reacts with SCl2 to give 1,2,3,5‐tetrathiane (25), 10 provides 9 on reaction with Cl2, 13 when treated with S2Cl2 affords C7H10S5 (12), 15 reacts with S2Cl2Cl2 to give C10H12S4. 17 and SCl2 yield 1,2,3,5,7‐pentathiepane (18), 20 is converted to C6H10S7 (22) on reaction with SCl2, and 23 yields S10 and 1,2,‐C6H4(SCl)2, respectively. With phosgene, thiophosgene, and thionyl chloride, compound 15 yields the corresponding dithiocarbonate 26, the trithiocarbonate 27 and the trisulfane 2‐oxide 28. The structure of 27 was determined by X‐ray crystallography.
Electroactive Protecting Groups and Reaction Units, 6. – Titanium Enolate Radical Cations in Solution: Generation, Characterization, and Their Reactions
Authors: Schmittel Michael , Söllner Rolf
Published: July 2007

For the first time titanium enolate radical cations were characterized in cyclic voltammetry experiments. Preparative one‐electron oxidation of titanium enolates1‐3led to the formation of benzofuransB1‐B3through mesolytic Ti‐O bond fragmentation to α‐carbonyl radical and a cationic titanocene(IV) species. With 1+·, the kinetics of the Ti‐O bond cleavage was investigated by fast scan cyclic voltammetry providing a first‐order rate constant k1=850 ± 50 s−1in acetonitrile at room temperature. The titanium enolate radical cations1+·, 3+·, 4+·and 5%%were characterized by EPR spectroscopy, qualifying these species as electrophilic radicals. This feature can be exploited in CC bond formation reactions such as the formal dimerization of6to 2,3‐dimethyl‐1,4‐diphenylbuta‐1,4‐dioneD6, which takes place on stage of the radical cation 6+·.
Organometallic Molybdenum(V) Complexes with Promary Phosphane Ligands — Syntheses, Spectroscopic Properties, and Crystal Structures of [Cp′MoCl4(PH2R)] (R=2,4,6‐Pri3C6H2, Cyclohexyl, Cp′=C5H4Me)
Authors: Felsberg Reinhard , Blsurock Steffen , Jelonek Svea , Gelbrich Thomas , Kirmse Reinhard , Voigt Andreas , Hey‐Hawkins Evamarie
Published: July 2007

[Cp′MoCl4(CH3CN) (Cp′=C5H4Me) react with 2,4,6‐triisopropylphenylphosphane or cyclohexylphosphane to give the phosphane complexes [Cp′MoCl4(PH2R)] [R=2,4,6‐Pri3C6H2 (1)]. 1 and 2, were characterized spectroscopically (IR, MS) and by crystal structure determinations. EPR investigations in liquid and frozen solution confirmed the presence of Mo(V) species and the data were used to analyze the spin‐density distribution in the first coordination sphere.
Aminotroponimines as Ligands for Yttrium and Lanthanide Complexes
Authors: Roesky Peter W.
Published: July 2007

The reaction of N‐isopropyl‐2‐(isopropylamino)troponimine, [(i‐Pr)2ATI]H, with KH in THF affords [(i‐Pr)2ATI]K. This is a useful starting material for the preparation of the mono‐, bis‐ and tris‐substituted compounds [[i‐Pr)2ATI]YCl2‐(THF)2}2, [(i‐Pr)2ATI2Y[O(2,6,t‐Bu2C6H3)] and [(i‐Pr)2‐ATI]3Ln (Ln = Y, La, Sm), which can be obtained from ([i‐Pr)2ATI]K and LnX3 and LnX3 (X = Cl, I), or Y[O(2,6‐t‐BuC6H3)]3. All compounds have been characterized by spectroscopic methods. The monosubstituted yttrium complex {[(i‐Pr)2ATI]YCl2(THF)2}2 has also been investigated by single crystal X‐ray diffraction.
Bis[2‐(oxazolinyl)phenolato]oxovanadium(IV) Complexes: Syntheses, Crystal Structures and Catalyses
Authors: Boln Carsten , Luong Thi Kim Khanh , Harms Klaus
Published: July 2007

The syntheses and X‐ray crystal structures of two chiral bis[2‐(oxazolinyl)phenolato]‐oxovanadium(IV) complexes are reported. Their catalytic activity in oxidative transformations and C‐C bond‐forming reactions has been investigated.
Gold Coordination by Tertiary Phosphane Sulfides
Authors: Preisenberger Max , Bauer Andreas , Schmidbaur Hubert
Published: July 2007

Treatment of the ditertiary phosphane sulfides (CH2)n[PPh2S]2, 1a–1d, n = 1‐4, with equivalent amounts of (dimethylsulfide)gold(I) chloride (Me2S)AuC1 affords the dinuclear complexes 2a–2d with an AuCl unit attached to each sulfur atom. The chlorides can be converted into the bromides 3a–3c by metathesis using KBr, or by reacting 1d with (tetrahydrothiophene)gold bromide. With [(Ph3P)Au]+ O3SCF3 as the aurating agent for the diphosphane disulfides, the corresponding dicationic products are obtained: {(CH2)n[SPPh2AuPPh3]2}2+ · 2 O3SCF3 (4b‐4d, n = 2‐4). An excess of the reagents does not lead to polygold clustering at the sulfur atoms, and P‐S cleavage occurs instead to give sulfonium salts {S[Au(PPh3)]3}+ X−. The reaction of Ph3PS with equimolar quantities of [ (Ph3P)Au]O3SCF3 leads to the cationic 1:1 complex 5, and with an excess of the agent the P–S bond is ruptured. The structures of compounds 4b and 4d were determined by single‐crystal X‐ray diffraction. The dications have crystallographic centers ot inversion, the coordination at the gold atoms is linear [4b: 179.03(3)° 4d: 175.29(2)°] and the angles at the sulfur atoms are acute [4b: 97.76(4)° 4d: 96.37(3)°], but there are no short Au–Au contacts.
Characteristic Features of Neutral Cyclopropenylium‐Like Compounds: Synthesis, Structure, and Chemical Behavior of a Cyclopropenylioborate Betaine
Authors: Ahlers Wolfgang , Erker Gerhard , Fröhlich Roland , Zippel Frank
Published: July 2007

Bis(propynyl)zirconocene was treated with B(C6F.5)3 and then with two equivalents of tert‐butyl isocyanide to yield the organometallic three‐membered ring product 8. Subsequent hydrolysis gives the substituted (2‐iminioethylidene)cyclopropeneborate betaine system 9 that exhibits a pronounced cyclopropenylioborate betaine character. This follows from its characteristic structural features (X‐ray crystal‐structure analysis of the isomer cis‐9) and its chemical features. Complex 9 undergoes a very facile cis/trans isomerization by formal rotation around the exocyclic partial CC‐double bond (ΔG+ ≈ 17 kcal mol−1). Compound 9 reacts cleanly in methanol solution with tert‐butyl isocyanide by insertion and ring enlargement to form the four‐membered ring system 12. Compound 12 was also characterized by X‐ray diffraction.
Chiral Metal Carbene Modified [2.2]Metacyclophanes: Synthesis, Structure, and Chiroptic Properties
Authors: Lougen Andrea , Vögtle Fritz , Dötz Karl Heinz , Nieger Martin
Published: July 2007

Pentacarbonyl(4‐[2.2]metacyclophanyl(methoxy)carbene)‐chromium(0) (6) was prepared according to the Fischer route from 4‐bromo[2.2]metacyclophane. Aminolysis with non‐chiral and chiral amines affords aminocarbene complexes 7‐12. X‐Ray structure analyses for 6 and its aminocarbene analogs 7 and 8 indicate that the incorporation of the chromium‐carbene fragment has no significant influence on the deformation of the [2.2]metacyclophane skeleton.
The Molecular Structures of Tetra(amino)silanes
Authors: Huber Gerald , Schier Annette , Schmidbaur Hubert
Published: July 2007

In a search for crystalline homoleptic tetra(amin)silanes with (mirror)‐symmetrical NR2 substituents, tetrakis( 1‐pyrrolidinyl)silane (1) was prepared by an improved synthetic route, and tetrakis(morpholino)silane (2) was synthesized from SiBr4 and morpholine/Li‐morpholide via the intermediate BrSi[N(CH2CH2)2O]3 (4). With SiCl4 only the monochloro stage, 3, is reached. Tetrakis(4‐methyl‐1‐piperazinyl)silane (5) was prepared similarly, using 4‐methylpiperazine. With (CH2)6NH or (CH2)6NLi and SiBr4 only [(CH2)6N]3SiBr (6) was obtained. The structures of 1, 2 and 5 were determined by single‐crystal X‐ray diffraction. While compound 1 has an irregular molecular geometry following no symmetrical pattern, molecules of 2 and 5 have similar structures with almost superimposable Si(NC2)4 cores of approximate D2d symmetry. The overall molecular symmetry of 2 is reduced only by incongruous folding of the heterocycles, which are all in a chair conformation. The core structures of 2 and 5 are in excellent agreement with the results of density function calculations for Si(NH2)4. Si(NMe2)4 (the crystal structure of which could not be determined) was converted into (Me2N)3SiO‐SO2CF3 (7) by treatment with two equivalents of triflic acid. Reaction of 7 with 1‐naphthylamine/triethylamine affords (Me2N)3SiNHC9H7 (8). With 2,4‐difluoroaniline/NEt3 the analogous derivative (Me2N)3SiNHC6H3F2 (9) is obtained, but with 4‐bromoaniline the product is a silane with the ligands redistributed to give (Me2N2),Si(NHC6H4Br), (10), the structure of which was also determined. It has a non‐standard geometry with very flat nitrogen pyramids at all four substituents.
On the Polymorphism of White Phosphorus
Authors: Simon Arndt , Borrmann Horst , Horakh Jörg
Published: July 2007

White phosphorus occurs in three modifications. The α form, which exists at roomtemperature, transforms reversibly to the β form at –77°C. The α · β transformation may be strongly delayed. Quenching the α form to –185°C followed by slow warming results in an exothermic reactions with formation of the γ form which transforms into the β form at –120°C in an endothermic reaction. A transition β · γ is not observed. The γ form is characterized by its powder diagram. The structure of the β form is redetermined from a single crystal at –185°C (P., α = 547.88(5), b = 1078.62(11), c = 1096.16(11)pm, α= 94.285(8), β = 99.695(7), γ = 100.680(7)., V = 623.79(10) · 106 pm3, Z = 6 formula units per cell). The P4 molecules exhibit pronounced librational motion in spite of the low temperature of investigation. The arrangement of the centers of the tetrahedra corresponds to the atom positions in the γ‐plutonium structure, which is discussed in relation to the bcc structure.