bluuebunny/crossref_metadata_2025 huggingface dataset:
Textile Tectonics: An Interview with Lars Spueybroek
Authors: Ludovica Tramontin Maria
Published: December 2006

‘Architectural design is not about having ideas, but about having techniques, techniques that operate on a material level. It's about making matter think and live by itself.’ Here Lars Spuybroek of NOX talks to Maria Ludovica Tramontin about his engagement with the work of Gottfried Semper and Frei Otto and how it has led him to his own brand of textile tectonics or ‘soft constructivism’, in which textiles are transformed into the tectonic through conventional textile techniques ‐ weaving, bundling, interlacing, braiding, knitting or knotting ‐ effectively building structure through softness and flexibility. Copyright © 2006 John Wiley & Sons, Ltd.
Camouflage as Aesthetic Sustainability
Authors: Richter Dagmar
Published: December 2006

A textile approach to architecture offers unique opportunities to explore a structure's surface and texture. Through a discussion of the history of the technique of camouflage and her own projects with Design Research and Development (DR_D), Dagmar Richter demonstrates the potential for surface enrichment to exceed mere ornament or patterning. A ‘performative texture’, camouflage interacts with its context mimicking the natural and effectively disguising whatever it covers. With a now long military association, camouflage also provides anything but a neutral background for its cover. Copyright © 2006 John Wiley & Sons, Ltd.
Parametric Matter
Authors: Obuchi Yusuke , Spyropoulos Theodore , Verebes Tom
Published: December 2006

The assimilation of digital techniques in production and manufacturing has enabled innovative explorations into nonstandard material organisation. Yusuke Obuchi, Theodore Spyropoulos and Tom Verebes of the Design Research Lab (DRL) at the Architectural Association (AA) describe how an interest in a textiles approach has developed out of a preoccupation with the interrelationship between material and computational design methods. They describe three projects that aspire to embed forms of material intelligence into architectural space. Copyright © 2006 John Wiley & Sons, Ltd.
Fabric Architecture and Flexible Design
Authors: Kronenburg Robert
Published: December 2006

Robert Kronenburg is one of the leading advocates of portable and flexible architecture. Over the last decade he has written substantial books and curated major international shows on the subject. Here he highlights how recent innovations in material and digital techniques have facilitated the onset of a new type of fabric architecture that is able to house increasingly larger and culturally more significant facilities. Outlining the most pertinent technological developments in the field, he also provides a comprehensive account of some of the most important projects. Copyright © 2006 John Wiley & Sons, Ltd.
Tensile Structure Design An Engineer's Perspective
Authors: Wakefield David
Published: December 2006

Here, David Wakefield, the founder of Tensys, an engineering consultancy that specialises in lightweight fabric structure analysis, describes the leading principles that underlie tensile structure design. He explains not only the application of materials and the importance of detailed stress analysis, but also where future developments might lie in this field. Copyright © 2006 John Wiley & Sons, Ltd.
Tectonics and Textiles
Authors: McQuaid Matilda
Published: December 2006

Technical textiles are now omnivalent ‐ used in many different everyday applications ‐ and have been adopted by civil engineers and physicians alike. In an exhibition, ‘Extreme Textiles’ at New York's Cooper‐Hewitt Museum last year, curator Matilda McQuaid brought these common but often ignored extraordinary materials to public attention. Here she highlights the high‐performance qualities of this very special category of materials. Copyright © 2006 John Wiley & Sons, Ltd.
Textiles for 21st Century Living
Authors: O'Mahony Marie
Published: December 2006

Here, Marie O'Mahony focuses on one of the most exciting areas of innovation for textiles ‐ the hybridisation of materials and engineering techniques. It is, as she explains, the very blurring of what a textile constitutes that opens up so many possibilities for material science and application in architecture. Copyright © 2006 John Wiley & Sons, Ltd.
The Hotel of Reflections
Authors: Watson Howard
Published: December 2006

Howard Watson describes the derelict 19th‐century alcohol factory on the Asian bank of the Bosphorus in Istanbul, which became a 30‐year restoration and renovation project for architects Nedret and Mark Butler. On the hotel's completion, their daughter Yasha realised an ingenious treatment of the interiors that takes its cue from the buildings' waterside setting. Copyright © 2006 John Wiley & Sons, Ltd.
National Waterfront Museum, Swansea
Authors: Melvin Jeremy
Published: December 2006

At the National Waterfront Museum in Swansea, Wales, Wilkinson Eyre Architects has united old and new structures, as well as maritime and industrial history. Jeremy Melvin describes the curatorial drive behind the museum's construction, and also how the architects have deftly drawn on their own experience of projects that have some association with industry and science. Copyright © 2006 John Wiley & Sons, Ltd.
Fiat Tagliero Service Station
Authors: Denison Edward
Published: December 2006

In 2006, the spotlight has very much been on the Modern Movement, with the major exhibition at the V&A in London ‐ ‘Modernism: Designing a New World 1914‐1936’. Here, Edward Denison describes how Giuseppe Pettazzi's Fiat Tagliero service station in Asmara in Eritrea, East Africa, epitomised Italy's futuristic ambitions for a new colony. Copyright © 2006 John Wiley & Sons, Ltd.
Stokes flow through a single‐screw extruder
Authors: Blyth M. G. , Pozrikidis C.
Published: December 2006

Stokes flow through a single‐screw extruder driven either by an axial pressure‐gradient, or by the rotation of the screw, or by a combination of both is analyzed. The geometry of the screw is chosen to resemble that encountered in the metering section of a real‐life industrial extruder. Working on the simplifying assumption of large helical pitch, a perturbation analysis is performed in non‐orthogonal helical coordinates, and contributions to the velocity and pressure fields are computed up to second‐order by finite element methods for unidirectional and two‐dimensional Stokes flow. Velocity fields are presented for different screw geometries, the axial flow rate is computed for pressure‐ and rotation‐driven flow, comparisons with simple models are made, and the effect of the pitch on the trajectories of passively convected particles is demonstrated. In the case of purely pressure‐driven flow, the flow rate decreases, whereas in the case of rotating flow the flow rate increases as the gap between the screw and the barrel is reduced. © 2006 American Institute of Chemical Engineers AIChE J, 2007
The characterization and classification of the Black River Upper Morass, Jamaica, using the three‐parameter test of vegetation, soils and hydrology
Authors: Azan Shakira , Webber Dale
Published: December 2006

The characterization and classification of the Black River Upper Morass was conducted using the criteria of the three‐parameter test for vegetation, soils and hydrology at 14 sites within the study area.

The Upper Morass exhibited 71% hydrophytic vegetation typical of wetlands (vascular and non‐vascular plants including Cladium jamaicense, Phragmites australis, Typha angustifolia and Sagittaria lancifolia) and 29% vegetation atypical of wetlands.

The Upper Morass is classified as a Palustrine System with sub‐classes of Aquatic Bed and Persistent Emergent Wetland.

The presence throughout the Upper Morass of monoculture stands of the invasive species Eichhornia crassipes and Typha domingensis, which are known to invade disturbed or partially drained wetlands, confirmed that the study area was a disturbed ecosystem.

The Upper Morass exhibited hydric (flood‐water and groundwater) soils, which, in association with its temporarily flooded and saturated wetland hydrology, indicated that it is groundwater‐driven.

Application of the three‐parameter test indicated a linkage between the functions of the Upper Morass and the Lower Morass, and thus a need for conservation of the Black River Morass System as a single unit rather than two independent wetlands. Two key instruments of conservation will be further detailed ecological assessments and the implementation of a management plan.

Copyright © 2006 John Wiley & Sons, Ltd.
Vegetation communities of British lakes: a revised classification scheme for conservation
Authors: Duigan Catherine , Kovach Warren , Palmer Margaret
Published: December 2006

A revised classification scheme is described for standing waters in Britain, based on the TWINSPAN analysis of a dataset of aquatic plant records from 3447 lakes in England, Wales and Scotland, which is held by the Joint Nature Conservation Committee.

Separate ecological descriptions of 11 distinct lake groups (A–J) are presented with summary environmental data, macrophyte constancy tables and maps showing their distribution. These lake groups include small dystrophic waters dominated bySphagnumspp.; large, acid, upland lakes supporting a diversity of plant species, includingJuncus bulbosus,Littorella uniflora,Lobelia dortmannaandMyriophyllum alterniflorum; low‐altitude, above‐neutral lakes with a high diversity of plant species, characterized by the presence ofPotamogetonspp.,Charaspp. or water‐lilies and other floating‐leaved vegetation; and coastal, brackish lakes, with macroalgae.

The Plant Lake Ecotype Index (PLEX) is presented as an indicator of changing lake environments. PLEX scores reflecting the new classification scheme have been developed for individual plant species and lakes. Applications of the index are demonstrated.

There is discussion of possible applications of the data collected and the resultant classification, in the context of the Habitats Directive, the Water Framework Directive and other conservation requirements.

© Crown copyright 2006. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
A comparison between the China Scientific and Technical Papers and Citations Database and the Science Citation Index in terms of journal hierarchies and interjournal citation relations
Authors: Zhou Ping , Leydesdorff Loet
Published: December 2006

The journal structure in the China Scientific and Technical Papers and Citations Database (CSTPCD) is analyzed from three perspectives: the database level, the specialty level, and the institutional level (i.e., university journals vs. journals issued by the Chinese Academy of Sciences). The results are compared with those for (Chinese) journals included in the Science Citation Index (SCI). The frequency of journal–journal citation relations in the CSTPCD is an order of magnitude lower than in the SCI. Chinese journals, especially high‐quality journals, prefer to cite international journals rather than domestic ones; however, Chinese journals do not get an equivalent reception from their international counterparts. The international visibility of Chinese journals is low, but varies among fields of science. Journals of the Chinese Academy of Sciences have a better reception in the international scientific community than university journals.
Towards understanding the roles of social capital in knowledge integration: A case study of a collaborative information systems project
Authors: Bhandar Mamata , Pan Shan‐Ling , Tan Bernard C.Y.
Published: December 2006

Information systems (IS) projects involving multiple organizations are very common today. Knowledge integration in such projects is a complex task of integrating diverse knowledge bases across organizations that may possess distinct strategic goals and even conflicting interests. Prior research has indicated that social capital, a resource based on social relationships, positively influences knowledge integration and interorganizational relationships, but the exact nature of the interaction has been unclear. Based on an in‐depth case study, this article examines a four‐organization (three clients and one IT service provider) collaborative IS project wherein the clients were business partners for 7 years when they embarked on the project. The study explicitly identifies the roles through which social capital can be leveraged for knowledge integration in a collaborative IS project. Findings suggest that social capital can be leveraged as a motivator, an integrator, and a facilitator during the various stages of a collaborative IS project.
Synthesis of a new π‐deficient phenylalanine derivative from a common 1,4‐diketone intermediate and study of the influence of aromatic density on prolyl amide isomer population
Authors: Dörr Aurélie , Lubell William D.
Published: December 2006

magnified image Enantiopure (2S)‐N‐(Boc)‐3‐(6‐methylpyridazinyl)alanine (14) has been synthesized to serve as a phenylalanine analog lacking significant π‐donor capability. Two approaches were developed to furnish the target compound from L‐aspartic acid as chiral educt in respectively six and nine steps and 13% and 12% yields. In both routes, a key homoallylic ketone intermediate was synthesized by a copper‐catalyzed cascade addition of vinylmagnesium bromide to a carboxylic ester. Dipeptide models Ac‐Xaa‐Pro‐NHMe (21a–c) were prepared and the relative populations of prolyl cis‐ and trans‐amide isomers were measured in chloroform, dimethylsulfoxide, and water by proton NMR spectroscopy in order to assess the significance of the electron density of the neighboring aromatic residue on the prolyl amide geometry. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 290–299, 2007.

This article was originally published online as an accepted preprint. The ‘Published Online’ date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
In vitro and in vivo confocal Raman study of human skin hydration: Assessment of a new moisturizing agent, pMPC
Authors: Chrit L. , Bastien P. , Biatry B. , Simonnet J.‐T. , Potter A. , Minondo A. M. , Flament F. , Bazin R. , Sockalingum G. D. , Leroy F. , Manfait M. , Hadjur C.
Published: December 2006

The hydration capacities of a biomimetic polymer, 2‐methacryloyloxethylphosphorylcholine polymer (pMPC), alone and microencapsulated, in association with another well known hydrating polymer, Hyaluronic acid, were investigated in vitro on skin models and in vivo on volunteers by using confocal Raman microspectroscopy. The hydration impact and the relative water content in the Stratum corneum were calculated from the Raman spectra using the OH (water)/CH3 (protein) ratio. Moreover, the follow‐up of the presence of pMPC through the Stratum corneum was possible with confocal Raman microspectroscopy, using a characteristic vibration of pMPC, different from that of the encapsulating material. From our in vitro measurements, the improved hydration of the Stratum corneum was confirmed by the use of the encapsulated form of pMPC, which was higher when combined with Hyaluronic acid. On the basis of these in vitro findings, we validated this trend in in vivo measurements on 26 volunteers, and found a good correlation with the in vitro results. Mechanical and ultrastructural studies have been carried out to demonstrate the positive effects of the pMPC on the Stratum corneum function, namely the interaction with lamellar lipids and the plasticizing effects, which are both supposed to spell out the moisturizing effect. This study demonstrates the efficiency of a original hydrating agent, pMPC, entrapped with Hyaluronic acid in a new type of microcapsules by the use of a novel tool developed for both in vitro and in vivo approaches. This indicates a new step to evaluate and improve new moisturizers in response to the cosmetics or dermatologic demands. © 2006 Wiley Periodicals, Inc. Biopolymers 85:359–369, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Stability of globular proteins in H2O and D2O
Authors: Efimova, Y. M. , Haemers, S. , Wierczinski, B. , Norde, W. , Well A. A. van
Published: December 2006

In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O–D2O solvent substitution on the stability of globular protein structure is determined in a systematic way. The differential scanning calorimetry technique is applied to allow for a thermodynamic analysis of two types of globular proteins: hen's egg lysozyme (LSZ) with relatively strong internal cohesion (“hard” globular protein) and bovine serum albumin (BSA), which is known for its conformational adaptability (“soft” globular protein). Both proteins tend to be more stable in D2O compared to H2O. We explain the increase of protein stability in D2O by the observation that D2O is a poorer solvent for nonpolar amino acids than H2O, implying that the hydrophobic effect is larger in D2O. In case of BSA the transitions between different isomeric forms, at low pH values the Nm and F forms, and at higher pH values Nm and B, were observed by the presence of a supplementary peak in the DSC thermogram. It appears that the pH‐range for which the Nm form is the preferred one is wider in D2O than in H2O. © 2006 Wiley Periodicals, Inc. Biopolymers 85: 264–273, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Analysis of structural changes in permanent waved human hair using Raman spectroscopy
Authors: Kuzuhara Akio
Published: December 2006

To investigate the mechanism leading to the reduction in tensile strength of permanent waved human hair, the structure of cross‐sections at various depths of permanent waved white human hair was directly analyzed without isolating the cuticle and cortex, using Raman spectroscopy. The β‐sheet and/or random coil content (β/R) and the Amide III(unordered) band intensity existing throughout the cortex region of virgin white human hair remarkably increased, while the α‐helix (α) content slightly decreased by performing the permanent waving treatment. This suggests a secondary structural change from the α‐helix form to the random coil form in the proteins existing in the microfibril of the cortex region. On the other hand, the SS band intensity existing in the matrix of the cortex region almost did not change, despite the reduction in the tensile strength of the white human hair following the permanent waving treatment. Moreover, the transmission electron microscope observation shows that the macrofibril (the microfibril and matrix) existing in the cortex region of the virgin white human hair was remarkably disturbed, while the cuticle region was almost unchanged by performing the permanent waving treatment. From these experiments, the authors concluded that some of proteins existing in the cortex region (the microfibril and matrix) of the virgin white human hair were changed, thereby leading to the remarkable reduction in the tensile strength of the white human hair after the permanent waving treatment. © 2006 Wiley Periodicals, Inc. Biopolymers 85: 274–283, 2007

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Extended abdominoperineal resection with gluteus maximus flap reconstruction of the pelvic floor for rectal cancer
Authors: Holm T , Ljung A , Häggmark T , Jurell G , Lagergren J
Published: December 2006

Background

Intraoperative tumour perforation, positive tumour margins, wound complications and local recurrence are frequent difficulties with conventional abdominoperineal resection (APR) for rectal cancer. An alternative technique is the extended posterior perineal approach with gluteus maximus flap reconstruction of the pelvic floor. The aim of this study was to report the technique and early experience of extended APR in a select cohort of patients.

Methods

The principles of operation are that the mesorectum is not dissected off the levator muscles, the perineal dissection is done in the prone position and the levator muscles are resected en bloc with the anus and lower rectum. The perineal defect is reconstructed with a gluteus maximus flap. Between 2001 and 2005, 28 patients with low rectal cancer were treated accordingly at the Karolinska Hospital.

Results

Two patients had ypT0 tumours, 20 ypT3 and six ypT4 tumours. Bowel perforation occurred in one, the circumferential resection margin (CRM) was positive in two, and four patients had local perineal wound complications. Two patients developed local recurrence after a median follow-up of 16 months.

Conclusion

The extended posterior perineal approach with gluteus maximus flap reconstruction in APR has a low risk of bowel perforation, CRM involvement and local perineal wound complications. The rate of local recurrence may be lower than with conventional APR.
Laparoscopic surgery impairs tissue oxygen tension more than open surgery
Authors: Fleischmann E , Kugener A , Kabon B , Kimberger O , Herbst F , Kurz A
Published: December 2006

Background

Wound infection remains a common and serious complication after colonic surgery. Although many colonic operations are performed laparoscopically, it remains unclear whether this has any impact on the incidence of wound infection. Subcutaneous tissue oxygenation is an excellent predictor of surgical wound infection. The impact of open and laparoscopic colonic surgery on tissue oxygenation was compared.

Methods

Fifty-two patients undergoing elective open and laparoscopic left-sided colonic resections were evaluated in a prospective observational study. Anaesthesia management was standardized and intraoperative arterial partial pressure of oxygen was kept at 150 mmHg in both groups. Oxygen tension was measured in the subcutaneous tissue of the right upper arm.

Results

At the start of surgery subcutaneous tissue oxygen tension (Psqo2) was similar in both groups (mean(s.d.) 65·8(17·2) and 63·7(23·6) mmHg for open and laparoscopic operations respectively; P = 0·714). Tissue oxygen remained stable in the open group, but dropped significantly in the laparoscopic group during the course of surgery (Psqo2 after operation 53·4(12·9) and 45·5(11·6) mmHg, respectively; P = 0·012).

Conclusion

Laparoscopic colonic surgery significantly decreases Psqo2, an effect that occurs early in the course of surgery. As tissue oxygen tension is a predictor of wound infection, these results may explain why the risk of wound infection after laparoscopic surgery remains higher than expected.
Novel Bcl‐2 Inhibitors: Discovery and Mechanism Study of Small Organic Apoptosis‐Inducing Agents
Authors: Zhang Zhichao , Jin Liji , Qian Xuhong , Wei Meijiao , Wang Yuanyuan , Wang Jing , Yang Yuanyuan , Xu Qin , Xu Yongting , Liu Fengyu
Published: December 2006

Apoptosis as a novel target for cancer chemotherapy has generated an intense demand for new apoptosis‐inducing agents. The newly revealed role of protein families involved in the apoptosis pathway, and resistance to cytotoxic therapies have opened new avenues for the development of novel anticancer strategies. We have established a novel strategy to rapidly obtain protein‐targeted, instead of conventional DNA‐targeted, apoptosis inducers as antitumor leads. First, a novel organic non‐DNA intercalative compound S1 (8‐oxo‐3‐thiomorpholin‐4‐yl‐8H‐acenaphtho[1,2‐b]pyrrole‐9‐carbonitrile, MW=331) was found with an IC50 of 10−7–10−8 μM against diverse cancer cell lines. Further biological evaluation demonstrated that it was an apoptosis‐inducer both in vivo and in vitro. The treatment of hydroperitoneum hepatoma cells (H22 cell line) with S1 at various concentrations (from 0.01 to 10 μM) for 24 h triggered these cells to enter the apoptosis process. The antitumor efficiency was also tested in the H22 xenotransplant models in mice. At a dosage of 0.3 mg kg−1, S1 exhibited significant antitumor activity with a much longer survival time, a decrease in tumor size, and increased apoptosis cells in tumor tissue. More importantly, studies of the molecular mechanism of apoptosis induction by S1 revealed that S1 inactivated the Bcl‐2 protein by binding to it, depolarizing the mitochondrial membrane, and then activating caspase 9, followed by caspase 3. Finally, structure‐based virtual modification was performed by computer modeling. As a result, a derivative, S2 (8‐oxo‐3‐[(thienylmethyl)amino]‐8H‐acenaphtho[1,2‐b]pyrrole‐9‐carbonitrile, MW=341) was identified that possessed a lower binding energy to Bcl‐2, and demonstrated better antitumor potency, even on the Bcl‐2‐overexpressing human acute myeloid leukemia (HL‐60) cells (IC50=1.3 μM) in vitro. S1 and S2 are the well‐defined Bcl‐2 inhibitors that give us a promising platform for the development of new therapeutic agents.
Generation of New Landomycins with Altered Saccharide Patterns through Over‐expression of the Glycosyltransferase Gene lanGT3 in the Biosynthetic Gene Cluster of Landomycin A in Streptomyces cyanogenus S‐136
Authors: Zhu Lili , Luzhetskyy Andriy , Luzhetska Martha , Mattingly Cynthia , Adams Val , Bechthold Andreas , Rohr Jürgen
Published: December 2006

Two novel landomycin compounds, landomycins I and J, were generated with a new mutant strain of Streptomyces cyanogenus in which the glycosyltransferase that is encoded by lanGT3 was over‐expressed. This mutant also produced the known landomycins A, B, and D. All these compounds consist of the same polyketide‐derived aglycon but differ in their sugar moieties, which are chains of different lengths. The major new metabolite, landomycin J, was found to consist of landomycinone with a tetrasaccharide chain attached. Combined with previous results of the production of landomycin E (which contains three sugars) by the LanGT3− mutant strain (obtained by targeted gene deletion of lanGT3), it was verified that LanGT3 is a D‐olivosyltransferase responsible for the transfer of the fourth sugar required for landomycin A biosynthesis. The experiments also showed that gene over‐expression is a powerful method for unbalancing biosynthetic pathways in order to generate new metabolites. The cytotoxicity of the new landomycins—compared to known ones—was assessed by using three different tumor cell lines, and their structure–activity relationship (SAR) with respect to the length of the deoxysugar side chain was deduced from the results.
Patent foramen ovale and migraine
Authors: Post M.C. , Luermans J.G.L.M. , Plokker H.W.M. , Budts W.
Published: December 2006

Migraine is a common neurological disorder with a great impact on the quality of life and social activities. The patent foramen ovale (PFO) is an intra‐atrial right‐to‐left shunt with a prevalence of 25% in the general population. An increased prevalence is found in patients with migraine, especially in migraine with aura. Percutaneous PFO closure might decrease the prevalence of migraine. However, most of these observational studies were retrospective without a randomized design and the results need to be interpreted with caution. In this review we describe the association between PFO and migraine and the different pathophysiological hypotheses, which have been proposed to explain this relationship. © 2006 Wiley‐Liss, Inc.
Dynamic Combinatorial Libraries Based on Hydrogen‐Bonded Molecular Boxes
Authors: Kerckhoffs Jessica M. C. A. , Mateos‐Timoneda Miguel A. , Reinhoudt David N. , Crego‐Calama Mercedes
Published: December 2006

This article describes two different types of dynamic combinatorial libraries of host and guest molecules. The first part of this article describes the encapsulation of alizarin trimer 2 a3 by dynamic mixtures of up to twenty different self‐assembled molecular receptors together with the amplification and selection of the best binder. Receptors (1 a–d)3⋅(DEB)6 are formed by the self‐assembly of six diethyl barbiturate (DEB) and calix[4]arene dimelamine derivatives 1 a–d by using hydrogen bonds. The largest amplification factor (2.8) for a host assembly (1 a3⋅ (DEB)6) was observed after the addition of 2 a to four‐component library 1 an⋅1 b(3−n)⋅(DEB)6 (n=0–3). Addition of 2 a to twenty‐component library 1 an⋅1 bm⋅1 co⋅1 d(3−(n+m+o))⋅(DEB)6 (n, m, o=0–3; (n+m+o)≤3) also showed amplification of receptor 1 a3⋅(DEB)6. The second part of this article describes the complexation of libraries of different alizarin‐like guest molecules (2 a–d) and the self‐assembled receptor 1 a3⋅(DEB)6. This receptor is able to template the formation of the best‐fitting guest trimer.
A locally conservative least‐squares method for Darcy flows
Authors: Bochev P. B. , Gunzburger M. D.
Published: December 2006

Least‐squares finite‐element methods for Darcy flow offer several advantages relative to the mixed‐Galerkin method: the avoidance of stability conditions between finite‐element spaces, the efficiency of solving symmetric and positive definite systems, and the convenience of using standard, continuous nodal elements for all variables. However, conventional C0 implementations conserve mass only approximately and for this reason they have found limited acceptance in applications where locally conservative velocity fields are of primary interest. In this paper, we show that a properly formulated compatible least‐squares method offers the same level of local conservation as a mixed method. The price paid for gaining favourable conservation properties is that one has to give up what is arguably the least important advantage attributed to least‐squares finite‐element methods: one can no longer use continuous nodal elements for all variables. As an added benefit, compatible least‐squares methods inherit the best computational properties of both Galerkin and mixed‐Galerkin methods and, in some cases, yield identical results, while offering the advantages of not having to deal with stability conditions and yielding positive definite discrete problems. Numerical results that illustrate our findings are provided. Copyright © 2006 John Wiley & Sons, Ltd.
The modified Shanks transform for the solution of elastic problems by boundary integral equation (BIE) method
Authors: Antes M. Y. , Karinski Y. S. , Yankelevsky D. Z.
Published: December 2006

A new approach which allows solving the elastic problems by the boundary integral equation (BIE) methods is presented. The solution of the integral equation is presented in the form of Neumann series and in order to accelerate its convergence the Shanks transform was applied in a modified form. Usage of this transform allows essentially the decrease of the number of Neumann series terms for complex geometrical forms of the bodies boundary. The BIE method to the class of problems characterized by mass potential forces (i.e. thermal, gravitational or centrifugal) is applied. The comparison with the known solution for the disturbed flow around a aerofoil shows good agreement. The method is demonstrated through an example of the stress analysis of a centrifugal high‐speed compressor working wheel. Copyright © 2006 John Wiley & Sons, Ltd.
A simple enzymatic method for parietal yolk sac removal in early postimplantation mouse embryos
Authors: Rivera‐Pérez Jaime A. , Diefes Hunter , Magnuson Terry
Published: December 2006

Crucial aspects of axial development in mice occur at early postimplantation stages from the time of implantation to the appearance of the primitive streak. However, this period of development is notoriously refractory to experimental approaches due to the small size of the conceptus and to the presence of the parietal yolk sac, a protective tripartite membrane that surrounds the developing egg cylinder. Here, we describe a method that combines enzymatic digestion and mechanical manipulation to remove the parietal yolk sac of conceptuses at stages between 5.5 and 6.5 days post coitum. This method, which is compatible with whole‐mount in situ hybridization and immunostaining techniques, offers a significant improvement over conventional dissection techniques, and it will greatly facilitate research in early mammalian development. Developmental Dynamics 236:489–493, 2007. © 2006 Wiley‐Liss, Inc.
The hippocampus is required for short‐term topographical memory in humans
Authors: Hartley Tom , Bird Chris M. , Chan Dennis , Cipolotti Lisa , Husain Masud , Vargha‐Khadem Faraneh , Burgess Neil
Published: December 2006

The hippocampus plays a crucial role within the neural systems for long‐term memory, but little if any role in the short‐term retention of some types of stimuli. Nonetheless, the hippocampus may be specialized for allocentric topographical processing, which impacts on short‐term memory or even perception. To investigate this we developed performance‐matched tests of perception (match‐to‐sample) and short‐term memory (2 s delayed‐match‐to‐sample) for the topography and for the nonspatial aspects of visual scenes. Four patients with focal hippocampal damage and one with more extensive damage, including right parahippocampal gyrus, were tested. All five patients showed impaired topographical memory and spared nonspatial processing in both memory and perception. Topographical perception was profoundly impaired in the patient with parahippocampal damage, mildly impaired in two of the hippocampal cases, and clearly preserved in the other two hippocampal cases (including one with dense amnesia). Our results suggest that the hippocampus supports allocentric topographical processing that is indispensable when appropriately tested after even very short delays, while the presence of the sample scene can allow successful topographical perception without it, possibly via a less flexible parahippocampal representation. © 2006 Wiley‐Liss, Inc.
Characterizing interneuron and pyramidal cells in the human medial temporal lobe in vivo using extracellular recordings
Authors: Viskontas Indre V. , Ekstrom Arne D. , Wilson Charles L. , Fried Itzhak
Published: December 2006

The goal of this study was to characterize the electrophysiological features of single neurons recorded deep within the medial temporal lobes in humans. Using three physiological criteria to distinguish principal cells and interneurons (firing rate, burst propensity, and action potential waveform) and a large data set of human single neurons (585) from thirteen patients, we show that single neurons in the human MTL separate into two distinct classes comparable to the pyramidal cell and interneuron classes described in animals. We also find that the four different MTL brain regions that we examined (amygdala, hippocampus, entorhinal cortex, and posterior parahippocampal cortex) show unique action potential characteristics, which may in turn relate to the role that neurons from these regions play in behavior. A subset of cells were recorded while patients engaged in both slow‐wave (SWS) and rapid‐eye movement (REM) sleep and a comparison of the electrophysiological features during these different sleep stages showed that interneurons tended to burst more during SWS compared to REM, while only principal cells in the EC and hippocampus showed a greater propensity for bursting during SWS. Together, our results support the idea that human single neurons have electrophysiologically identifiable cell types, similar to those observed in other mammals, and provide insight into regional and functional differences in spike‐wave characteristics relevant to considerations about neural populations in the human brain. © 2006 Wiley‐Liss, Inc.
Diatoms in Lowland Ponds of Koshi Tappu, Eastern Nepal – Relationships with Chemical and Habitat Characteristics
Authors: Simkhada Bishnu , Jüttner Ingrid , Chimonides P. James
Published: December 2006

Epiphytic and epipelic diatom assemblages were studied in relation to water chemistry and habitat character in lowland ponds of Koshi Tappu, Nepal. Epiphytic assemblages from different microhabitats, such as morphologically different plants, roots, stems, filamentous algae and decomposing leaves, within the same ponds were similar. Assemblage composition of epiphytic diatoms reflected gradients in water chemistry and habitat character of the pond with respect to pond vegetation and substratum type, bank profile and land use in the catchment. Epiphytic and epipelic assemblages responded to chemical gradients in the surface water, particularly concentrations of Ca, Mg and Na, but epipelic diatoms also indicated differences in SO4. Epipelic diatoms were also sensitive to interstitial water chemistry variations in PO4, Si, Ca and Mg. There were no relationships between species richness, diversity or evenness and gradients in water chemistry and habitat character. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Seasonal Changes on Predictive Model Assessments of Streams Water Quality with Macroinvertebrates
Authors: João Feio Maria , Reynoldson Trefor B. , Graça Manuel A.
Published: December 2006

In this study we investigate how seasonal variability in aquatic macroinvertebrate communities affects the performance of a predictive model developed to assess environmental quality. Macroinvertebrates were sampled from nine not visibly disturbed sites located in different streams of the Mondego catchment across a full year. Organisms were identified to the lowest practicable taxonomic level and their abundances recorded at three taxonomic levels (order, family and lowest level). The seasonal samples were examined with regard to seasonal variation using three predictive models at order, family and lowest taxonomic level. The models showed increasing effect of seasonal changes across taxonomic levels, from order to the lowest level. When using the current models samples should be taken in the same season as the reference sites were sampled. Furthermore, data from more reference sites should be added to the model in order to encompass sufficient natural variation and allow the use of the model in different seasons. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Morphological and Molecular Data Reveal the Presence of the Invasive Artemia franciscana in Margherita di Savoia Salterns (Italy)
Authors: Mura Graziella , Kappas Ilias , Baxevanis Athanasios D. , Moscatello Salvatore , D'Amico Quirico , Lopez German M. , Hontoria Francisco , Amat Francisco , Abatzopoulos Theodore J.
Published: December 2006

Introduced populations of the American invasive Artemia franciscana have been reported in Mediterranean countries except for Italy. A recent sampling at Margherita di Savoia revealed the presence of mating pairs in a saltwork known to host only parthenogens. An integrated approach, based on scanning electron microscopy of four morphological traits, discriminant analysis of 13 morphometric characters and 16S rRNA PCR‐RFLP profiles of eight endonucleases was implemented for the identification of the invader. Patterns of variability in all assayed markers provided congruent and solid evidence that the allochthonous species is A. franciscana. Native parthenogens are still predominant (∼98.4%) in this Italian site but they can be rapidly outcompeted by A. franciscana, as it occurred in similar cases throughout Europe and elsewhere. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recent advances in planar tetracoordinate carbon chemistry
Authors: Merino Gabriel , Méndez‐Rojas Miguel A. , Vela Alberto , Heine Thomas
Published: December 2006

We summarize our contributions on the quest of new planar tetracoordinate carbon entities (new carbon molecules with exotic chemical structures and strange bonding schemes). We give special emphasis on the rationalization why in this type of molecules the planar configuration is favored over the tetrahedral one. We will concentrate on the latter and will show that molecules containing planar tetracoordinate carbons have a stabilizing system of delocalized π electrons, which shows similar properties as π systems in aromatic molecules. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 362–372, 2007
Electrostatic energy in the effective fragment potential method: Theory and application to benzene dimer
Authors: Slipchenko Lyudmila V. , Gordon Mark S.
Published: December 2006

Evaluation of the electrostatic energy within the effective fragment potential (EFP) method is presented. The performance of two variants of the distributed multipole analysis (DMA) together with two different models for estimating the charge penetration energies was studied using six homonuclear dimers. The importance of damping the higher order multipole terms, i.e. charge dipole, was also investigated. Damping corrections recover more than 70% of the charge penetration energy in all dimers, whereas higher order damping introduces only minor improvement. Electrostatic energies calculated by the numerical DMA are less accurate than those calculated by the analytic DMA. Analysis of bonding in the benzene dimer shows that EFP with inclusion of the electrostatic damping term performs very well compared to the high‐level coupled cluster singles, doubles, and perturbative triples method. The largest error of 0.4 kcal/mol occurs for the sandwich dimer configuration. This error is about half the size of the corresponding error in second order perturbation theory. Thus, EFP in the current implementation is an accurate and computationally inexpensive method for calculating interaction energies in weakly bonded molecular complexes. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 276–291, 2007
The role of radial nodes of atomic orbitals for chemical bonding and the periodic table
Authors: Kaupp Martin
Published: December 2006

The role of radial nodes, or of their absence, in valence orbitals for chemical bonding and periodic trends is discussed from a unified viewpoint. In particular, we emphasize the special role of the absence of a radial node whenever a shell with angular quantum number l is occupied for the first time (lack of “primogenic repulsion”), as with the 1s, 2p, 3d, and 4f shells. Although the consequences of the very compact 2p shell (e.g. good isovalent hybridization, multiple bonding, high electronegativity, lone‐pair repulsion, octet rule) are relatively well known, it seems that some of the aspects of the very compact 3d shell in transition‐metal chemistry are less well appreciated, e.g., the often weakened and stretched bonds at equilibrium structure, the frequently colored complexes, and the importance of nondynamical electron‐correlation effects in bonding. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 320–325, 2006
How resonance assists hydrogen bonding interactions: An energy decomposition analysis
Authors: Beck John Frederick , Mo Yirong
Published: December 2006

Block‐localized wave function (BLW) method, which is a variant of theab initiovalence bond (VB) theory, was employed to explore the nature of resonance‐assisted hydrogen bonds (RAHBs) and to investigate the mechanism of synergistic interplay between π delocalization and hydrogen‐bonding interactions. We examined the dimers of formic acid, formamide, 4‐pyrimidinone, 2‐pyridinone, 2‐hydroxpyridine, and 2‐hydroxycyclopenta‐2,4‐dien‐1‐one. In addition, we studied the interactions in β‐diketone enols with a simplified model, namely the hydrogen bonds of 3‐hydroxypropenal with both ethenol and formaldehyde. The intermolecular interaction energies, either with or without the involvement of π resonance, were decomposed into the Hitler‐London energy (ΔEHL), polarization energy (ΔEpol), charge transfer energy (ΔECT), and electron correlation energy (ΔEcor) terms. This allows for the examination of the character of hydrogen bonds and the impact of π conjugation on hydrogen bonding interactions. Although it has been proposed that resonance‐assisted hydrogen bonds are accompanied with an increasing of covalency character, our analyses showed that the enhanced interactions mostly originate from the classical dipole–dipole (i.e., electrostatic) attraction, as resonance redistributes the electron density and increases the dipole moments in monomers. The covalency of hydrogen bonds, however, changes very little. This disputes the belief that RAHB is primarily covalent in nature. Accordingly, we recommend the term “resonance‐assisted binding (RAB)” instead of “resonance‐assisted hydrogen bonding (RHAB)” to highlight the electrostatic, which is a long‐range effect, rather than the electron transfer nature of the enhanced stabilization in RAHBs. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 455–466, 2007
Rehybridization as a general mechanism for maximizing chemical and supramolecular bonding and a driving force for chemical reactions
Authors: Alabugin Igor V. , Manoharan Mariappan
Published: December 2006

Dynamic variations in hybridization patterns (rehybridization) were analyzed at B3LYP/6–31G** and MP2/6–31+G* levels. Computations clearly illustrate the generality of rehybridization in a variety of chemical phenomena, which involve structural reorganization in hydrogen‐bonded complexes, nonhyperconjugative stereoelectronic effects in saturated heterocycles, Mills‐Nixon effect, and contrasting substituent effects in cycloaromatization reactions. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 373–390, 2007
Maximum probability domains from Quantum Monte Carlo calculations
Authors: Scemama Anthony , Caffarel Michel , Savin Andreas
Published: December 2006

Although it would be tempting to associate the Lewis structures to the maxima of the squared wave function |Ψ|2, we prefer in this paper the use of domains of the three‐dimensional space, which maximize the probability of containing opposite‐spin electron pairs. We find for simple systems (CH4, H2O, Ne, N2, C2H2) domains comparable to those obtained with the electron localization function (ELF) or by localizing molecular orbitals. The different domains we define can overlap, and this gives an interesting physical picture of the floppiness of CHand of the symmetric hydrogen bond in FHF−. The presence of multiple solutions has an analogy with resonant structures, as shown in the trans‐bent structure of Si2H2. Correlated wave functions were used (MCSCF or Slater‐Jastrow) in the Variational Quantum Monte Carlo framework. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 442–454, 2007