bluuebunny/crossref_metadata_2025 huggingface dataset:
The change in membrane phospholipid composition influences protein secretion and cell envelope biogenesis in Escherichia coli
Authors: Badyakina Alla , Vasil’eva Natalia , Koryakina Yulia , Anisimova Elena , Suzina Natalia , Nesmeyanova Marina
Published: August 2007

Secretion of periplasmic alkaline phosphatase (PhoA) encoded by the gene constituent of plasmids and the peculiar properties of cell envelope biogenesis in Escherichia coli strains with controlled synthesis of individual membrane phospholipids have been studied. Alkaline phosphatase secretion across the cytoplasmic membrane declines, while secretion into the culture medium intensifies under changed metabolism. The composition of anionic membrane phospholipids changes due to inactivation of the pgsA gene or regulation of its expression by environmental factor, as well as in the absence of the pssA gene which is responsible for the synthesis of the precursor for zwitter-ionic phospholipid — phosphatidylethanolamine. This correlates with intensified secretion of exopolysaccharides and lower content of lipopolysaccharide and lipoprotein which are responsible for barrier properties of the outer membrane. The results suggest a possible coupling of protein secretion with biogenesis of cell envelope components at a level of phospholipid metabolism.
Comparison of the MFA to the AOFAS Outcome Tool in a Population Undergoing Total Ankle Replacement
Authors: Pena Fernando , Agel Julie , Coetzee J. Chris
Published: August 2007

Background

Little information is available on the American Orthopaedic Foot and Ankle Society (AOFAS) outcome tool and its capacity to show changes and improvement in function of patients without a floor or ceiling effect. The purpose of the study was to compare results from the Musculoskeletal Functional Assessment (MFA) and AOFAS outcome tools in a population undergoing a total ankle replacement.

Methods

Prospective data was collected on 154 patients preoperatively and at 6, 12, and 24 months after surgery. An analysis was performed between both and within each tool across the time of followup.

Results

No ceiling or floor effect was noticed on the AOFAS outcome tool. Its capacity for discrimination and to observe changes in pain and function are acceptable. No correlation between the AOFAS categories of pain and function and the MFA domain of well being could be found. Both outcome tools presented similar responses.

Conclusions

Though the AOFAS outcome tool seems to have enough sensitivity to analyze pain and function during a postoperative period, the authors strongly recommend the use of an alternative outcome tool to better understand and delineate the patient's level of function and effect of treatment on their quality of life.

Clinical Relevance

These data improve the understanding of and indications for the AOFAS outcome tool. They confirm the AOFAS questionnaire as a tool with enough discriminatory capacity to assess patient improvement and also point out the weaknesses of the questionnaire and the importance of collecting parallel data with other available outcome tools to better understand patient function and quality of life.
Transverse Medial Slide Osteotomy for Bunionette Deformity: Long-Term Results
Authors: Weitzel Stefan , Trnka Hans-Joerg , Petroutsas Jason
Published: August 2007

Background

Bunionette deformity of the fifth metatarsal infrequently requires operative treatment. This study presents the long-term results of a simple operative technique.

Methods

Forty-four distal metatarsal medial slide osteotomies with pin fixation were performed for symptomatic bunionette deformity in 30 patients. After an average of 7 years and 8 months (range 69 to 110 months), 30 feet in 21 patients were available for clinical and radiographic evaluation.

Results

The patients’ subjective assessment was excellent and good in 81% and fair and poor in 19% of feet. The mean pain score on a visual analogue scale was 1.8 (range 0 to 7) and the mean American Orthopaedic Foot and Ankle Society (AOFAS) score was 88.2 (range 47 to 100). Postoperative complications included pin track infection in three feet and delayed union in one. One patient developed transfer metatarsalgia and another patient had repeat surgery for recurrent symptoms on both feet after 5 years.

Conclusions

This procedure combines technical simplicity with satisfactory and predictable long-term results in the operative treatment of bunionette deformity in the lateral forefoot.
Correction of Tailor's Bunion with the Boesch Technique: A Retrospective Study
Authors: Legenstein Robert , Bonomo Johannes , Huber Wolfgang , Boesch Peter
Published: August 2007

Background

The Boesch technique 1 , 2 is a minimally-invasive and time-saving subcutaneous subcapital metatarsal osteotomy. Since 1984, we have been using this osteotomy technique for patients with a symptomatic tailor's bunion in whom conservative treatment has failed. This distal osteotomy is stabilized by a combination of a Kirschner wire and a special dressing. The results of this technique in patients with symptomatic tailor's bunion were reviewed.

Methods

Between March, 1998, and June, 2002, surgery was done in 77 feet of 65 patients with a mean age of 64.6 years. The mean followup was 56.6 (range 14 to 79) months. The 100-point American Orthopaedic foot and Ankle Society (AOFAS) Lesser Metatarsophalangeal-Interphalangeal Scale was used for scoring.

Results

86.4% of 57 patients (66 feet) were free of pain at final followup. The mean 4–5 intermetatarsal angle was 12 degrees before and 8 degrees after surgery. The mean lateral deviation of the fifth metatarsal was 5.7 degrees before and 5.1 degrees after surgery. The mean fifth metatarsophalangeal angle was 17.8 degrees before and 6.2 degrees after surgery. The mean preoperative 100-point AOFAS score was 59.1 (range 23 to 88) and the postoperative score, 95.2 (range 73 to 100). The overall results were excellent in 87.9%, (58 feet) good in 6.1% (4 feet), and satisfactory in 6.1%; none was poor.

Conclusions

The advantages of the subcutaneous subcapital Boesch technique are that it is time saving, it causes less bone and soft-tissue trauma, and it is performed under local anesthesia without a tourniquet. It is an effective operative option for symptomatic tailor's bunion; excellent and good clinical and radiographic results were found in 86.4% (57 patients, 66 feet) of the patients.
Biomechanical Analysis of Screw-Augmented Intramedullary Fixation for Tibiotalocalcaneal Arthrodesis
Authors: O'Neill Patrick J. , Parks Brent G. , Walsh Russell , Simmons Lucia M. , Schon Lew C.
Published: August 2007

Background

This study compared intramedullary (IM) fixation for tibiotalocalcaneal arthrodesis with and without a tibiotalocalcaneal augmentation screw.

Methods

Each specimen in six matched pairs of fresh frozen cadavers underwent tibiotalocalcaneal arthrodesis with an IM nail. One specimen from each pair also received a tibiotalocalcaneal augmentation screw. Initial and final stiffness, load to failure, and construct deformation at failure were calculated with dorsiflexion loading. Bone mineral density of each pair was determined. Statistical analysis was done using a paired Student t-test and a Pearson correlation.

Results

Initial and final stiffness and load to failure were significantly higher for the tibiotalocalcaneal screw augmented fixation group as compared with the specimens with no additional screw (initial stiffness, 128.0 versus 78.4 N/mm, p = 0.04; final stiffness, 230.9 versus 164.7 N/mm, p = 0.04; load to failure, 875.5 versus 660.2 N, p = 0.03). There was a significant negative correlation between bone mineral density and average construct deformation in the samples without the added tibiotalocalcaneal screw ( r = –0.90, p = 0.02).

Conclusions

In tibiotalocalcaneal arthrodesis with intramedullary nail fixation, a tibiotalocalcaneal augmentation screw provides more stable fixation.

Clinical relevance

Use of an augmentation screw as described in this study may lead to lower complication rates, particularly in patients with osteopenic bone.
The Influence of Foot Position on Stretching of the Plantar Fascia
Authors: Flanigan Ryan M. , Nawoczenski Deborah A. , Chen Linlin , Wu Hulin , DiGiovanni Benedict F.
Published: August 2007

Background

A recent study found nonweightbearing stretching exercises specific to the plantar fascia to be superior to the standard program of weightbearing Achilles tendon-stretching exercises in patients with chronic plantar fasciitis. The present study used a cadaver model to demonstrate the influence of foot and ankle position on stretching of the plantar fascia.

Methods

Twelve fresh-frozen lower-leg specimens were tested in 15 different configurations representing various combinations of ankle and metatarsophalangeal (MTP) joint dorsiflexion, midtarsal transverse plane abduction and adduction, and forefoot varus and valgus. Measurements were recorded by a differential variable reluctance transducer (DVRT) implanted into the medial band of the plantar fascia, and primary measurement was a percent deformation of the plantar fascia (stretch) with respect to a reference position (90 degrees ankle dorsiflexion, 0 degrees midtarsal and forefoot orientation, and 0 degrees MTP dorsiflexion).

Results

Ankle and MTP joint dorsiflexion produced a significant increase (14.91%) in stretch compared to the position of either ankle dorsiflexion alone (9.31% increase, p < 0.001) or MTP dorsiflexion alone (7.33% increase, p < 0.01). There was no significant increase in stretch with positions of abduction or varus (2.49%, p = 0.27 and 0.55%, p = 0.79).

Conclusion

This study provides a mechanical explanation for enhanced outcomes in recent clinical trials using plantar fascia tissue-specific stretching exercises and lends support to the use of ankle and MTP joint dorsiflexion when employing stretching protocols for nonoperative treatment in patients with chronic proximal plantar fasciitis.
External Fixation in the Treatment of Tibial Pilon Fractures: Comparison of Two Frames in Torsion
Authors: Scott Aaron T. , Owen John R. , Khiatani Vishal , Adelaar Robert S. , Wayne Jennifer S.
Published: August 2007

Background

Ankle spanning external fixation has become the initial treatment of choice for complex tibial pilon fractures. Many fixator designs exist, but their biomechanical performance has not been studied extensively for this application. The goal of the present study was to compare the torsional performance of two commercially available frames, the Orthofix XCaliber and the Howmedica Hoffmann® II.

Methods

The XCaliber and the Hoffmann® II were each applied to six fresh cadaver lower extremities and were loaded in a materials testing machine. Strain gauges were attached to the anteromedial cortex of the distal tibia, and each specimen underwent torsional and axial load testing, with and without the external fixator. A simulated pilon fracture was created, and torsional testing was repeated.

Results

Results indicated that the XCaliber was significantly more rigid in internal rotation than the Hoffmann® II, before (49%) and after (41%) creation of the pilon fracture. Despite the XCaliber's increased rigidity relative to the Hoffmann® II (22% to 31%) in external rotation, statistical significance was not attained. Both fixators reduced strain (25% to 85%) at the anteromedial cortex upon torsional testing, but no significant differences between the two frames were noted.

Conclusions

The present study demonstrates that the XCaliber has mechanical advantages over the Hoffmann® II in terms of torsional rigidity for a tibial pilon fracture.

Clinical Relevance

Increased rigidity of the XCaliber could potentially lead to decreased time to union, and a lower incidence of pin loosening and would prove beneficial in a setting in which the external fixator is used as the definitive fixation.
Orthopaedic Surgery Core Curriculum: Foot and Ankle Reconstruction
Authors: Wadey Veronica M.R. , Halpern Jerry , Younger Alastair S.E. , Dev Parvati , Olshen Richard A. , Walker Decker
Published: August 2007

Background

The purpose of this study was to develop a core curriculum for orthopaedic surgery and to conduct a national survey to assess the importance of 281 curriculum items. Attention was focused on 45 items pertaining to the foot and ankle.

Methods

A 281-item curriculum was developed. A content review and cross-sectional survey of a random selection of orthopaedic surgeons with primary nonacademic affiliations was completed. Data were analyzed descriptively and quantitatively using histograms, modified Hotelling's T2-statistic, and the Benjamini-Hochberg procedure. Our analyses assumed that each respondent answered questions independently of the answers of any other respondent but that the answers to different questions by the same respondent might be dependent.

Results

Of the 156 orthopaedic surgeons contacted, 131 (86%) participated in this study. Eighty-two percent (37 of 45) of the items were ranked by respondents with an average mean score higher than 3.5/4.0 and 42 higher than 3.0/40, thus suggesting that 93% of the items are important or probably important to know by the end of residency ( p = 0.07).

Conclusion

This study demonstrated agreement on the importance of 93% of the items that pertain to foot and ankle reconstruction to be included in a core curriculum for orthopaedic surgery. The ability to make diagnoses and to manage common fractures, soft-tissue conditions, and arthritic conditions of the foot and ankle are very important for residents to know upon graduation from their residency programs. The exceptions to these are the ability to perform primary and revision arthroplasty of the ankle.
Electric-field induced phase transition in a near-surface layer of a PbMg0.33Nb0.67O3-28% PbTiO3 (001) single-crystalline plate
Authors: Levin Alexandr A. , Pommrich Anja I. , Weißbach Torsten , Paufler Peter , Meyer Dirk C.
Published: August 2007

An (001) single-crystal plate of a solid solution of PbMg1/3Nb2/3O3-28 mol.% PbTiO3 was investigated by Wide-Angle X-ray Scattering techniques at room temperature in situ under the influence of an external static electric field (field strength E up to 13 kV cm−1) applied along the [001] direction of the wafer. Structural changes attributed to a reversible phase transition between ferroelectric modifications of the solid solution in a near electrode region of about 1 mm depth are found. Part of the near-electrode layer (of about 5 vol.% at E = 4.5 kV cm−1 and about 15 vol.% at 13 kV cm−1) transforms from the initial rhombohedral structure to another one, most probably, the monoclinic Mb phase. Changes of the profile shape of X-ray rocking curves suggest possible technical use of the electric-field induced phase transition for adaptive X-ray optics.
Delamination of stiff islands patterned on stretchable substrates
Authors: Lu Nanshu , Yoon Juil , Suo Zhigang
Published: August 2007

In one design of flexible electronics, thin-film islands of a stiff material are fabricated on a polymeric substrate, and functional materials are grown on these islands. When the substrate is stretched, the deformation is mainly accommodated by the substrate, and the islands and functional materials experience relatively small strains. Experiments have shown that, however, for a given amount of stretch, the islands exceeding a certain size may delaminate from the substrate. We calculate the energy release rate using a combination of finite element and complex variable methods. Our results show that the energy release rate diminishes as the island size or substrate stiffness decreases. Consequently, the critical island size is large when the substrate is compliant. We also obtain an analytical expression for the energy release rate of debonding islands from a very compliant substrate.
Self-assembly of high-performance multi-tube carbon nanotube field-effect transistors by ac dielectrophoresis
Authors: Taeger Sebastian , Mertig Michael
Published: August 2007

A physical self-assembly process based on ac-dielectrophoretic deposition of single-walled carbon nanotubes between metallic electrodes and subsequent gate-voltage controlled elimination of the metallic nanotubes is reported that allows fabrication of multi-tube carbon nanotube field-effect transistors with electrical ON/OFF ratios up to more than seven orders of magnitude. Before deposition, the carbon nanotubes were suspended by means of single-stranded DNA or sodium-taurodeoxycholate. Exposure of the devices to ethanol vapor revealed a higher sensitivity for devices made from DNA-suspended carbon nanotubes.
Thin Films of Insoluble Poly(Oligothienylene vinylenes) Prepared by Chemical Vapor Deposition Polymerization
Authors: Joo S.‐H. , Lee C.‐Y. , Park D. , Joo J. , Jin J.‐I.
Published: August 2007

A series of poly(oligothienylene vinylenes) (PTmVs,m = 2–4) with a varying number of consecutively bound thienylene rings are successfully prepared in thin films by chemical vapor deposition polymerization (CVDP) using the corresponding bis(halomethyl)thiophenes as starting materials. The chemical and electronic structures are studied spectroscopically and also by cyclic voltammetry. Top‐gate field‐effect transistors are fabricated by two consecutive CVDP cycles of PTmV and poly(p‐xylylene) followed by the deposition of a Au gate electrode. In the case of a PT3V active layer, a field‐effect mobility value of 0.5 × 10–4 cm2 V–1 s–1is obtained.
Template‐Synthesized Protein Macroporous Biofilms: Conformational Related Direct Electron Transfer
Authors: Song Y.‐Y. , Jia W.‐Z. , Yang C. , Xia X.‐H.
Published: August 2007

We report on the synthesis of three‐dimensionally ordered structure (3D) of macroporous cytochrome c (cyt‐c) biofilms by using the inverted colloidal polystyrene crystal template technique and Triton X‐100 as entrapping matrix. Electrochemical impedance spectroscopic (EIS) measurements reveal that the immobilized cyt‐c molecules exhibit fast interfacial electron‐communication rate. We found that the orientation of the cyt‐c molecules entrapped in the 3D macroporous structure was determined by the interfacial electric field. Higher interfacial electric field limits the reorientational flexibility of the entrapped cyt‐c molecules, resulting in lower intermolecular electron‐communication rate constant (k°). Therefore, the highest intermolecular electron‐communication rate constant can only be obtained at potentials approaching to the potential of zero charge of the gold electrode, since k° is mainly determined by the molecular orientation in the biofilm. In addition, the prepared biofilms with enhanced functional density could find potential application in the bioelectronic sensing system.
Cover Picture: Low‐Work‐Function Surface Formed by Solution‐Processed and Thermally Deposited Nanoscale Layers of Cesium Carbonate (Adv. Funct. Mater. 12/2007)
Authors: Huang J. , Xu Z. , Yang Y.
Published: August 2007

The cover shows the structure of an efficient polymer light emitting diode (PLED) and its energy diagram at the interface between aluminum (Al) and a Cs2CO3 interfacial layer. It reveals the origin of enhanced electron injection from the Al electrode due to the low work function of a thermally evaporated Cs2CO3 layer, as reported on p. 1966 by Jinsong Huang, Zhen Xu, and Yang Yang. Pictures of the white‐ and red‐emitting PLEDs are also shown.

Nanostructured layers of Cs2CO3 are shown to function very effectively as cathodes in organic electronic devices because of their good electron‐injection capabilities. Here, we report a comprehensive study of the origin of the low work function of nanostructured layers of Cs2CO3 prepared by solution deposition and thermal evaporation. The nanoscale Cs2CO3 layers are probed by various characterization methods including current–voltage (I–V) measurements, photovoltaic studies, X‐ray photoelectron spectroscopy (XPS), UV photoelectron spectroscopy (UPS), and impedance spectroscopy. It is found that thermally evaporated Cs2CO3 decomposes into CsO2 and cesium suboxides. The cesium suboxides dope CsO2, yielding a heavily doped n‐type semiconductor with an intrinsically low work function. As a result, devices fabricated using thermally evaporated Cs2CO3 are relatively insensitive to the choice of the cathode metal. The reaction of thermally evaporated Cs2CO3 with Al can further reduce the work function to 2.1 eV by forming an Al–O–Cs complex. Solution‐processed Cs2CO3 also reduces the work function of Au substrates from 5.1 to 3.5 eV. However, devices prepared using solution‐processed Cs2CO3 exhibit high efficiency only if a reactive metal such as Al or Ca is used as the cathode metal. A strong chemical reaction occurs between spin‐coated Cs2CO3 and thermally evaporated Al. An Al–O—Cs complex is formed as a result of this chemical reaction at the interface, and this layer significantly reduces the work function of the cathode. Finally, impedance spectroscopy results prove that this layer is highly conductive.
Imaging of amyloid burden and distribution in cerebral amyloid angiopathy
Authors: Johnson Keith A. , Gregas Matt , Becker John A. , Kinnecom Catherine , Salat David H. , Moran Erin K. , Smith Erin E. , Rosand Jonathan , Rentz Dorene M. , Klunk William E. , Mathis Chester A. , Price Julie C. , DeKosky Steven T. , Fischman Alan J. , Greenberg Steven M.
Published: August 2007

Objective

Cerebrovascular deposition of β‐amyloid (cerebral amyloid angiopathy [CAA]) is a major cause of hemorrhagic stroke and a likely contributor to vascular cognitive impairment. We evaluated positron emission tomographic imaging with the β‐amyloid–binding compound Pittsburgh Compound B (PiB) as a potential noninvasive method for detection of CAA. We hypothesized that amyloid deposition would be observed with PiB in CAA, and based on the occipital predilection of CAA pathology and associated hemorrhages, that specific PiB retention would be disproportionately greater in occipital lobes.

Methods

We compared specific cortical PiB retention in 6 nondemented subjects diagnosed with probable CAA with 15 healthy control subjects and 9 patients with probable Alzheimer's disease (AD).

Results

All CAA and AD subjects were PiB‐positive, both by distribution volume ratio measurements and by visual inspection of positron emission tomographic images. Global cortical PiB retention was significantly increased in CAA (distribution volume ratio 1.18 ± 0.06) relative to healthy control subjects (1.04 ± 0.10; p = 0.0009), but was lower in CAA than in AD subjects (1.41 ± 0.17; p = 0.002). The occipital‐to‐global PiB ratio, however, was significantly greater in CAA than in AD subjects (0.99 ± 0.07 vs 0.86 ± 0.05; p = 0.003).

Interpretation

We conclude that PiB‐positron emission tomography can detect cerebrovascular β‐amyloid and may serve as a method for identifying the extent of CAA in living subjects. Ann Neurol 2007
Tau and α‐synuclein in susceptibility to, and dementia in, Parkinson's disease
Authors: Goris An , Williams‐Gray Caroline H. , Clark Graeme R. , Foltynie Thomas , Lewis Simon J. G. , Brown Joanne , Ban Maria , Spillantini Maria G. , Compston Alastair , Burn David J. , Chinnery Patrick F. , Barker Roger A. , Sawcer Stephen J.
Published: August 2007

Objective

Parkinson's disease (PD) is a neurodegenerative condition that typically presents as a movement disorder but is known to be associated with variable degrees of cognitive impairment including dementia. We investigated the genetic basis of susceptibility to and cognitive heterogeneity of this disease.

Methods

In 659 PD patients, 109 of which were followed up for 3.5 years from diagnosis, and 2,176 control subjects, we studied candidate genes involved in protein aggregation and inclusion body formation, the pathological hallmark of parkinsonism: microtubule‐associated protein tau (MAPT), glycogen synthase kinase‐3β (GSK3B), and α‐synuclein (SNCA).

Results

We observed that cognitive decline and the development of PD dementia are strongly associated (p = 10−4) with the inversion polymorphism containing MAPT. We also found a novel synergistic interaction between the MAPT inversion polymorphism and the single nucleotide polymorphism rs356219 from the 3′ region of SNCA. In our data, carrying a risk genotype at either of these loci marginally increases the risk for development of PD, whereas carrying the combination of risk genotypes at both loci approximately doubles the risk for development of the disease (p = 3 × 10−6).

Interpretation

Our data support the hypothesis that tau and α‐synuclein are involved in shared or converging pathways in the pathogenesis of PD, and suggest that the tau inversion influences the development of cognitive impairment and dementia in patients with idiopathic PD. These findings have potentially important implications for understanding the interface between tau and α‐synuclein pathways in neurodegenerative disorders and for unraveling the biological basis for cognitive impairment and dementia in PD. Ann Neurol 2007
Preparation of size‐controlled In2O3 nanoparticles
Authors: Zhu Peng , Wu Weiya , Zhou Jianping , Zhang Wu
Published: August 2007

Highly crystalline and monodisperse In2O3 nanoparticles were successfully prepared by thermal decomposition of In(dipy)3Cl3·2H2O in oleylamine and oleic acid under inert atmosphere. The size of In2O3 nanoparticles could be readily tuned from 10–15 nm to 40–50 nm, depending on the molar ratio of precursor to combined solvent in the reaction system. As‐synthesized In2O3 nanoparticles have a center‐body cubic structure as characterized by powder X‐ray diffraction and selected‐area electron diffraction. Transmission electron microscopy images showed that In2O3 nanoparticles have a narrow size distribution. A relatively strongly PL peak centered at 378 nm could be clearly seen when 10–15 nm In2O3 nanoparticles redispersed in cyclohexane were excited at 275 nm at room temperature. Copyright © 2007 John Wiley & Sons, Ltd.
Estimation and econometric tests under price and output uncertainties
Authors: Alghalith Moawia
Published: August 2007

We extend the existing estimation methods to allow empirical estimation and hypothesis testing under simultaneous price and output uncertainty. Our approach modifies and expands the use of duality theory. Furthermore, our approach does not require the specification or estimation of the production/cost function. In addition, our approach does not require the assumption of the statistical independence between price and output. Copyright © 2007 John Wiley & Sons, Ltd.
A look at US–Brazil ethanol trade and policy
Authors: Gallagher Paul W.
Published: August 2007

Brazil and the USA are experiencing an “ethanol investment boom”. Agriculture in both countries is being reorganized to boost biomass production, but duties and tariffs may fi nally dictate the way the nations adjust to increasing demand, says Paul W. Gallagher. © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd
The complex p25/Cdk5 kinase in neurofibrillary degeneration and neuronal death: The missing link to cell cycle
Authors: Hamdane Malika , Buée Luc
Published: August 2007

Emergence of the cell cycle hypothesis in neurodegenerative disease comes from the numerous lines of evidence showing a tight link between “cell cycle‐like reactivation” and neuronal death. Terminally differentiated neurons remain in G0 phase and display, compared to proliferating cells, an opposite regulation pattern of cell cycle markers in that most of the key activators and inhibitors are respectively down‐ and up‐regulated. It has been clearly established that any experimental attempt to force terminally differentiated neurons to divide ultimately leads to their death. Conversely, cell cycle blockade in experimental models of neuronal death is able to rescue neurons. Hence, cell cycle deregulation is certainly among mechanisms governing neuronal death. However, many questions remain unresolved, especially those related to which molecular mechanisms trigger cell cycle deregulation and how this deregulation leads to cell death. In the present review, we focus on neurodegeneration in Alzheimer's disease and discuss the cell cycle deregulation related to this neurodegenerative pathology. Finally, we emphasize the role of p25/Cdk5 kinase complex in this pathological process through retinoblastoma protein phosphorylation and derepression of E2F‐responsive genes and other actors such as cdc2, cyclins, and MCM proteins.
Aristolochene Synthase‐Catalyzed Cyclization of 2‐Fluorofarnesyl‐Diphosphate to 2‐Fluorogermacrene A
Authors: Miller David J. , Yu Fanglei , Allemann Rudolf K.
Published: August 2007

The mechanism of the conversion of (E,E)‐farnesyl diphosphate (FPP, 1 a) to aristolochene (6) catalyzed by aristolochene synthase from Penicillium roqueforti has been proposed to proceed through the neutral intermediate germacrene A (4 a). However, much of the experimental evidence is also in agreement with a mechanism in which germacrene A is not an intermediate in the predominant mechanism that leads to the formation of aristolochene, but rather an off‐pathway product that is formed in a side reaction. Hence, to elucidate the mechanism of FPP cyclisation the substrate analogue 2‐fluoroFPP (1 b) was synthesized, and upon incubation with aristolochene synthase was converted to a single pentane extractable product according to GC‐MS analysis. On the basis of NMR analyses this product was identified as 2‐fluorogermacrene A (4 b). Variable temperature 1H NMR spectroscopy indicated the existence of two conformers of 4 b that were in slow exchange at −60 °C, while at 90 °C the two isomers gave rise to averaged NMR signals. In the major isomer (∼75 %) the methyl groups on C3 and C7 were most likely in the down–down orientation as had been observed for other (E,E)‐germacranes. This work suggests that after an initial concerted cyclisation of FPP to germacryl cation deprotonation leads to the formation of germacrene A, and provides compelling evidence that germacrene A is indeed an on‐pathway product of catalysis by aristolochene synthase.
ChemoAC: its contribution to the advancement of Chemometrics
Authors: Vandeginste BGM , Smeyers‐Verbeke J.
Published: August 2007

The impact of ChemoAC—a consortium of industry and the laboratory headed by Professor Massart at the Vrije Universiteit Brussel—on the advancement of Chemometrics is discussed by reviewing its 50 most important chemometric papers. Copyright © 2007 John Wiley & Sons, Ltd.
Focused hierarchical design of peptide libraries—follow the lead
Authors: Muthas Daniel , Lek Per M. , Nurbo Johanna , Karlén Anders , Lundstedt Torbjörn
Published: August 2007

A novel design strategy based on the hierarchical design of experiments (HDoE) method named focused hierarchical design of experiments (FHDoE) is presented. FHDoE combine two design layers and use focused substitutions to increase the probability of obtaining active peptides when designing libraries through a selection of compounds biased towards a lead structure. Increasing the number of peptides with measurable activity will increase the information gained and the likelihood of constructing good quantitative structure–activity relationship (QSAR) models. The utility of the novel design method is verified using two different approaches. First, a library designed with the novel FHDoE method was compared with libraries generated from classical positional scanning techniques (e.g., alanine scan) as well as with general and centered minimum analog peptide sets (MAPS) libraries by using an example found in the literature. Secondly, the same design strategies were applied to a dataset of 58 angiotensin converting enzyme (ACE) dipeptide inhibitors. QSAR models were generated from designed sublibraries and the activities of the remaining compounds were predicted. These two examples show that the use of FHDoE renders peptide libraries close in physicochemical space to the native ligand, yielding a more thorough screening of the area of interest as compared to the classical positional scans and fractional factorial design (FFD). It is also shown that an FHDoE library of six dipeptides could produce a QSAR model that better described the requisites of high activity ACE inhibitors than could QSAR models built from either a nine‐dipeptide library designed with MAPS or a 58‐dipeptide library. Copyright © 2007 John Wiley & Sons, Ltd.
Modelling crack propagation in structures: Comparison of numerical methods
Authors: Yang Xin‐She , Lees Janet M. , Morley Chris T.
Published: August 2007

Crack propagation in concrete structures is a very complicated process, and the distribution of cracks may significantly affect the behaviour of the structures under time‐dependent loading. If enough damage or extensive cracks exist in a structure, strengthening or repair using external carbon fibre‐reinforced polymer (CFRP) reinforcement may be needed. Therefore, an understanding of the influence of the CFRP strengthening system on behaviour is crucial for the proper design of a structural reinforcement strategy. In this paper, we compare three major methods: the discrete crack method, the smeared crack method and the element‐free method. By using these methods to study the fracture pattern of a beam with dapped ends, we can compare the capabilities and efficiencies of the three methods. When modelling the crack formation in reinforced concrete structures, the smeared crack approach gives better results than the discrete model in terms of crack spacing and regularity, however, it does not follow the crack growth well. The element‐free Galerkin method seems to be superior to the other methods in the sense that it deals with the irregular cracks well and is very efficient in saving computing time. The preferred choice of method depends on the type of problem and the solution accuracy required, and this also depends on a certain balance between the accurate tracing of individual cracks and the computing efficiency. In addition, new algorithms are required for the efficient simulations of dynamic crack propagation, especially in the case of pre‐cracked structures strengthened with prestressed CFRPs. Copyright © 2007 John Wiley & Sons, Ltd.
Embryonic cardiomyocyte expression of endothelial genes
Authors: Welikson Robert E. , Kaestner Stefanie , Evans Angela M. , Hauschka Stephen D.
Published: August 2007

Vertebrate precardiac mesoderm contains cells destined to become cardiomyocyte or endothelial cells. To determine the stability of these phenotypes freshly isolated embryonic day (E) 2.5–E6 chicken hearts were immunostained for myosin heavy chain (MyHC) to identify cardiomyocytes, and von Willebrand factor (vWF) and Flk‐1 to identify endothelial cells. At E2.5–E3, 90% of cells express only MyHC and 6% express only vWF/Flk‐1. However, 2% MyHC+ cells in E2.5–E3 hearts and 0.3% in E4–E6 hearts, also express vWF/Flk‐1; and when cultured 3 days, >40% of the MyHC+ cells express vWF/Flk‐1, but they do not express Vezf1, vascular endothelial cadherin, or Tie2. Thus, only a subset of endothelial genes are induced in cultured cardiomyocytes. While the subsequent developmental fate of embryonic heart cells exhibiting a vWF+/MyHC+ phenotype is unknown, analysis of this phenotype may provide information pertinent to mechanisms of cell phenotype stability, cellular transdifferentiation, and induction of stable cell types from embryonic stem cells. Developmental Dynamics 236:2512–2522, 2007. © 2007 Wiley‐Liss, Inc.
Comorbidity and high‐risk behaviors in treatment‐seeking adolescents with bulimia nervosa
Authors: Fischer Sarah , Grange Daniel le
Published: August 2007

Objective:

The purpose of this brief report is to describe the comorbid diagnoses and high‐risk behaviors in a sample of adolescents with bulimia nervosa (BN).

Method:

Eighty adolescents enrolled in a RCT for BN that compared family‐based therapy with individual‐supportive psychotherapy completed the Eating Disorder Examination and the Schedule for Affective Disorder and Schizophrenia for School Age Children (K‐SADS).

Results:

A total of 62.5% of the sample had a comorbid diagnosis as determined by the K‐SADS. The majority of these presented with a major mood disorder. In addition, 25% of the sample had previously attempted suicide or self‐harmed, 65.8% had consumed alcohol, and 30% had used illegal drugs. Suicidal behavior, drug use, and presence of a comorbid diagnosis were not related to diagnosis (full BN vs. subthreshold BN) or age.

Conclusion:

Comorbidity and high‐risk health behaviors in adolescents with BN mirror those of adults with BN although not at similar rates. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
An Efficient Synthesis of (–)‐Posticlure: The Sex Pheromone of Orgyia postica
Authors: Fernandes Rodney A.
Published: August 2007

An efficient multigram synthesis of (–)‐posticlure, the first trans‐epoxide sex pheromone found in Orgyia postica, from diethyl L‐tartrate is described. The synthesis was completed in seven steps and 27 % overall yield. The synthetic strategy features double‐Wittig olefination and a stereoselective one‐pot conversion of diol to epoxide as the key steps. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Flexible routing in a distributed K‐ary tree: the K‐Umbrella
Authors: Sotiriou Athanasios‐Dimitrios , Kalliaras Panagiotis , Mitrou Nikolas
Published: August 2007

As peer‐to‐peer (P2P) applications become more mature and demanding, there is a need for the underlying technologies to provide more adaptive characteristics, according to the application's requirements. In this paper, we present K‐Umbrella, a K‐ary distributed hash table (DHT), which allows us to efficiently route through the use of a fixed‐size routing table. By controlling a number of parameters, our algorithm is able to trade‐off between efficiency, fault‐tolerance and decentralisation according to the application's requirements. Through a detailed analysis of our algorithms and an extensive set of simulations, we will show that our protocol is able to offer an improved alternative to current DHT algorithms. Copyright © 2007 John Wiley & Sons, Ltd.
Stability of some low‐order approximations for the Stokes problem
Authors: Nafa Kamel
Published: August 2007

Two‐level low‐order finite element approximations are considered for the inhomogeneous Stokes equations. The elements introduced are attractive because of their simplicity and computational efficiency. In this paper, the stability of a Q1(h)–Q1(2h) approximation is analysed for general geometries. Using the macroelement technique, we prove the stability condition for both two‐ and three‐dimensional problems. As a result, optimal rates of convergence are found for the velocity and pressure approximations. Numerical results for three test problems are presented. We observe that for the computed examples, the accuracy of the two‐level bilinear approximation is compared favourably with some standard finite elements. Copyright © 2007 John Wiley & Sons, Ltd.
Biliverdin inhibits activation of NF‐κB: Reversal of inhibition by human biliverdin reductase
Authors: Gibbs Peter E.M. , Maines Mahin D.
Published: August 2007

hBVR functions in the cell as a reductase and as a kinase. In the first capacity, it reduces biliverdin, the product of HO activity, to the effective intracellular antioxidant, bilirubin; as a dual‐specificity kinase (S/T/Y) it activates the MAPK and IGF/IRK receptor signal transduction pathways. NF‐κB and the MAPK pathway are activated by ROS, which results in the activation of stress‐inducible genes, including ho‐1. Presently, we report on the negative effect of biliverdin on NF‐κB activation and the converse effect of hBVR. Biliverdin, in a concentration‐ and time‐dependent manner, inhibited transcriptional activity of NF‐κB in HEK293A cells. Nuclear extracts from biliverdin‐treated cells show reduced DNA binding of NF‐κB in an electromobility shift assay, whereas extracts from cells treated with TNF‐α showed enhanced binding. Coimmunoprecipitation data show hBVR binds to the 65 kDa subunit of NF‐κB, and that this is dependent on activation by TNF‐α. Overexpression of hBVR enhanced both the basal and TNF‐α‐mediated activation of NF‐κB and also that of the NF‐κB‐activated iNOS gene. Also, overexpression of hBVR arrested the cell cycle in the G1/G0 phase and reduced the number of cells in S phase. Similar results were observed with MCF‐7 cells. Because of the Janus nature of NF‐κB activity in the cell and the inhibitory action of biliverdin, the present findings provide a foundation for therapeutic intervention in inflammatory diseases and cancer that may be attained by preventing reduction of biliverdin. On the other hand, by increasing BVR levels beneficial functions of NF‐κB might be augmented. © 2007 Wiley‐Liss, Inc.
Hedgehog signaling pathway is inactive in colorectal cancer cell lines
Authors: Chatel Guillaume , Ganeff Corine , Boussif Naima , Delacroix Laurence , Briquet Alexandra , Nolens Gregory , Winkler Rosita
Published: August 2007

The Hedgehog (Hh) signaling pathway plays an important role in human development. Abnormal activation of this pathway has been observed in several types of human cancers, such as the upper gastro‐intestinal tract cancers. However, activation of the Hh pathway in colorectal cancers is controversial. We analyzed the expression of the main key members of the Hh pathway in 7 colon cancer cell lines in order to discover whether the pathway is constitutively active in these cells. We estimated the expression of SHH, IHH, PTCH, SMO, GLI1, GLI2, GLI3, SUFU and HHIP genes by RT‐PCR. Moreover, Hh ligand, Gli3 and Sufu protein levels were quantified by western blotting. None of the cell lines expressed the complete set of Hh pathway members. The ligands were absent from Colo320 and HCT116 cells, Smo from Colo205, HT29 and WiDr. GLI1 gene was not expressed in SW480 cells nor were GLI2/GLI3 in Colo205 or Caco‐2 cells. Furthermore the repressive form of Gli3, characteristic of an inactive pathway, was detected in SW480 and Colo320 cells. Finally treatment of colon cancer cells with cyclopamine, a specific inhibitor of the Hh pathway, did not downregulate PTCH and GLI1 genes expression in the colorectal cells, whereas it did so in PANC1 control cells. Taken together, these results indicate that the aberrant activation of the Hh signaling pathway is not common in colorectal cancer cell lines. © 2007 Wiley‐Liss, Inc.
Proliferative capacity and osteogenic potential of novel dura mater stem cells on poly‐lactic‐co‐glycolic acid
Authors: Petrie Caren , Tholpady Sunil , Ogle Roy , Botchwey Edward
Published: August 2007

The rational design of biomimetic structures for the regeneration of damaged or missing tissue is a fundamental principle of tissue engineering. Multiple variables must be optimized, ranging from the scaffold type to the selection and properties of implanted cell(s). In this study, the osteogenic potential of a novel stem cell was analyzed on biodegradable poly(lactic‐co‐glycolic acid) (PLGA) biomaterials as a step toward creating new cell‐materials constructs for bony regeneration. Dura mater stem cells (DSCs), isolated from rat dura mater, were evaluated and compared to bone marrow stem cells (BMSCs) for proliferative and differentiative properties in vitro. Experiments were carried out on both tissue culture plastic (TCP) and 2D planar films of PLGA. Proliferation of DSCs on both TCP and PLGA films increased over 21 days. Positive fold inductions in all five bone marker genes were observed at days 7, 14, 21 in all experimental samples compared with day 0 controls. DSCs demonstrated greater cell coverage and enhanced matrix staining on 2D PLGA films when compared with BMSCs. These cells can be isolated and expanded in culture and can subsequently attach, proliferate, and differentiate on both TCP and PLGA films to a greater extent than BMSCs. This suggests that DSCs are promising for cell‐based bone tissue engineering therapies, particularly those applications involving regeneration of cranial bones. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
β‐CaSiO3/β‐Ca3(PO4)2 composite materials for hard tissue repair: In vitro studies
Authors: Ni Siyu , Lin Kaili , Chang Jiang , Chou Lee
Published: August 2007

In this study, a series of β‐CaSiO3 (CS)/β‐Ca3(PO4)2 (TCP) composites with different ratios were prepared to produce new bioactive and biodegradable biomaterials for potential bone repair. The mechanical properties of CS‐TCP composites increased steadily with the increase of TCP amounts in composites. Formation of bone‐like apatite on a range of CS‐TCP composites with CS weight percentage ranging from 0 to 100 has been investigated in simulated body fluid (SBF). The presence of bone‐like apatite layer on the composite surface after soaking in SBF was demonstrated by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and fourier transform infrared reflection spectroscopy (FTIR). The results showed that the apatite formation ability of the CS‐TCP composite was enhanced with increasing CS content in the composites. For composites with more than 50% CS contents, the samples were completely covered by a layer of dense bone‐like apatite just after 3 days immersion. Dissolution tests in Tris‐HCl buffer solution showed obvious differences with different CS contents in composites. The dissolution rate increased with the increase of CS content, which suggested that the solubility of biphasic composites could be tailored by adjusting the initial CS/TCP ratio. In vitro cell experiments showed that higher content of CS phase in composites promoted cell proliferation and differentiation. When the CS amount in the composite increased to 50%, the proliferation rate and ALP activities of osteoblast‐like cells showed significant difference compared with pure TCP (p < 0.05). Results of the study suggested that the CS‐TCP composites with more than 50% CS content might be promising bone repair materials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Gonadal differentiation and hormonal sex reversal in arctic charr (Salvelinus alpinus)
Authors: Chiasson Marcia , Benfey Tillmann J.
Published: August 2007

The purpose of this study was to develop a practical protocol for the production of female populations of Arctic charr (Salvelinus alpinus). Achieving this required knowledge of the timing of gonadal differentiation. Undifferentiated gonads were observed microscopically to be present by 194°C‐days post‐hatch and definitive germ cells by 346°C‐days post‐hatch, where “°C‐days” denote acquired thermal units calculated as the product of temperature and days. Some of the gonads had developed a lumen by 510°C‐days post‐hatch, and by 681°C‐days post‐hatch anatomical divergence into two types of gonads was clear. Two protocols (immersion and feeding) were tested for hormonal sex reversal of genotypic females using the synthetic androgen 17α‐methyldihydrotestosterone (MDHT). Six‐hour MDHT immersions (0.5, 1, 3, 5 and 10 mg/L) were carried out weekly from hatch to first feeding (140°C‐days post‐hatch), whereas daily feeding treatments (0.5 mg/kg) went from 140 to 600°C‐days post‐hatch. The sex ratios of all immersion experimental groups were significantly different from the control, with the proportion of presumptive males increasing as MDHT concentration increased. The highest immersion treatment, 10 mg/L, yielded a population of 90% presumptive males and 10% with atypical gonads. However, the most effective treatment, yielding a population of 90% presumptive males and no fish with atypical gonads, was the feeding treatment. Given that female salmonid fishes are homogametic, sex‐reversed (masculinized) genotypic females produced in this way can serve as broodstock for the creation of all‐female charr populations for aquaculture. J. Exp. Zool. 307A:527–534, 2007. © 2007 Wiley‐Liss, Inc.