bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth response of young, thinned Douglas-fir stands to nitrogen fertilizer in relation to soil properties and tree nutrition
Authors: Hopmans P. , Chappell H.N.
Published: February 2008

Application of 224 kg N/ha to young, thinned stands of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) at 35 sites in western Oregon and Washington significantly increased basal area and volume increment over 8 years following treatment. However, response varied considerably between sites, and relative volume increment exceeded 10% at only 19 of the 35 sites. Response to applied N was evaluated in relation to forest floor and soil variables as well as to levels of N in foliage. Relative responses in basal area and volume were significantly correlated with total N concentration and the C/N ratio of the soil. However, these relationships explained only part (18–22%) of the observed variation in response. In contrast, relative response was strongly correlated with the level of N in the foliage of nonfertilized trees at 11 sites, accounting for 94% of the variation between sites. Use of foliar N data clearly has potential to predict growth responses to N fertilization of young thinned Douglas-fir stands, although further work is needed to test the relationship for a wider range of sites and stands.
Factors affecting the incidence of black seed rot in slash pine
Authors: Fraedrich S.W. , Miller T. , Zarnoch S.J.
Published: February 2008

Black seed rot of slash pine (Pinuselliottii Engelm. van elliottii) caused by Lasiodiplodiatheobromae (Pat.) Griff. & Maubl. was found to be a postharvest disease favored by premature cone harvests in conjunction with certain cone collection practices. The incidence of fungus-damaged seeds was greatest in cones collected on the earliest collection date and left in contact with the ground before storage. The incidence of disease decreased with later collection dates. Fungus-damaged seeds were not present in cones dried immediately after collection, regardless of the collection date. Fungi were rarely established in seeds at the time that cones were removed from trees; they apparently colonized seeds and caused disease during cone harvest and storage. Based on cone specific gravity and results of seed germination tests, cones and seeds were not mature on the earliest collection date. Lasiodiplodiatheobromae was associated with a majority of seeds that were fungus-damaged. Sphaeropsissapinea (Fr.) Dyko & Sutton and a Fusicoccum sp. also were recovered from seeds; however, their relative importance in slash pine seed disease was minor.
Using Complicated, Wide Dynamic Range Driving to Develop Models of Single Neurons in Single Recording Sessions
Authors: Hobbs Kevin H. , Hooper Scott L.
Published: February 2008

Neuron models are typically built by measuring individually, for each membrane conductance, its parameters (e.g., half-maximal voltages) and maximal conductance value ( gmax). However, neurons have extended morphologies with nonuniform conductance distributions, whereas models generally contain at most a few compartments. Both the original conductance measurements and the models therefore unavoidably contain error due to the electrical filtering of neurons and the differential placement of conductances on them. Model parameters (typically gmax values) are therefore generally altered by hand or brute force to match model and neuron activity. We propose an alternative method in which complicated, rapidly changing driving input is used to optimize model parameters. This method also ensures that neuron and model dynamics match across a wide dynamic range, a test not performed in most modeling. We tested this concept using leech heartbeat and generic tonically firing models and lobster stomatogastric and generic bursting models as targets and gmax values as optimized parameters. In all four cases optimization solutions excellently matched target activity. Complicated, wide dynamic range driving thus appears to be an excellent method to characterize neuron properties in detail and to build highly accurate models. In these completely defined targets, the method found each target's 8–13 gmax values with high accuracy, and may therefore also provide an alternative, functionally based method of defining neuron gmax values. The method uses only standard experimental and computational techniques, could be easily extended to optimize conductance parameters other than gmax, and should be readily applicable to real neurons.
Angiopoietin-1 promotes endothelial cell proliferation and migration through AP-1–dependent autocrine production of interleukin-8
Authors: Abdel-Malak Nelly A. , Srikant Coimbatore B. , Kristof Arnold S. , Magder Sheldon A. , Di Battista John A. , Hussain Sabah N. A.
Published: February 2008

Angiopoietin-1 (Ang-1), ligand for the endothelial cell–specific Tie-2 receptors, promotes migration and proliferation of endothelial cells, however, whether these effects are promoted through the release of a secondary mediator remains unclear. In this study, we assessed whether Ang-1 promotes endothelial cell migration and proliferation through the release of interleukin-8 (IL-8). Ang-1 elicited in human umbilical vein endothelial cells (HUVECs) a dose- and time-dependent increase in IL-8 production as a result of induction of mRNA and enhanced mRNA stability of IL-8 transcripts. IL-8 production is also elevated in HUVECs transduced with retroviruses expressing Ang-1. Neutralization of IL-8 in these cells with a specific antibody significantly attenuated proliferation and migration and induced caspase-3 activation. Exposure to Ang-1 triggered a significant increase in DNA binding of activator protein-1 (AP-1) to a relatively short fragment of IL-8 promoter. Upstream from the AP-1 complex, up-regulation of IL-8 transcription by Ang-1 was mediated through the Erk1/2, SAPK/JNK, and PI-3 kinase pathways, which triggered c-Jun phosphorylation on Ser63 and Ser73. These results suggest that promotion of endothelial migration and proliferation by Ang-1 is mediated, in part, through the production of IL-8, which acts in an autocrine fashion to suppress apoptosis and facilitate cell proliferation and migration.
Modulation of murine embryonic stem cell–derived CD41+c-kit+ hematopoietic progenitors by ectopic expression of Cdx genes
Authors: McKinney-Freeman Shannon L. , Lengerke Claudia , Jang Il-Ho , Schmitt Sabine , Wang Yuan , Philitas Marsha , Shea Jessica , Daley George Q.
Published: February 2008

Cdx1, Cdx2, and Cdx4 comprise the caudal-like Cdx gene family in mammals, whose homologues regulate hematopoietic development in zebrafish. Previously, we reported that overexpression of Cdx4 enhances hematopoietic potential from murine embryonic stem cells (ESCs). Here we compare the effect of ectopic Cdx1, Cdx2, and Cdx4 on the differentiation of murine ESC-derived hematopoietic progenitors. The 3 Cdx genes differentially influence the formation and differentiation of hematopoietic progenitors within a CD41+c-kit+ population of embryoid body (EB)–derived cells. Cdx1 and Cdx4 enhance, whereas Cdx2 strongly inhibits, the hematopoietic potential of CD41+ckit+ EB-derived cells, changes that are reflected by effects on hematopoietic lineage-specific and Hox gene expression. When we subject stromal cell and colony assay cultures of EB-derived hematopoietic progenitors to ectopic expression of Cdx genes, Cdx4 dramatically enhances, whereas Cdx1 and Cdx2 both inhibit hematopoietic activity, probably by blocking progenitor differentiation. These data demonstrate distinct effects of Cdx genes on hematopoietic progenitor formation and differentiation, insights that we are using to facilitate efforts at in vitro culture of hematopoietic progenitors from ESC. The behavior of Cdx genes in vitro suggests how derangement of these developmental regulators might contribute to leukemogenesis.
Human Langerhans cells selectively activated via Toll-like receptor 2 agonists acquire migratory and CD4+T cell stimulatory capacity
Authors: Peiser Matthias , Koeck Juliana , Kirschning Carsten J , Wittig Burghardt , Wanner Reinhard
Published: February 2008

In epidermal Langerhans cells (LCs), the expression pattern and the functions of TLRs have been poorly characterized. By using mAb, we show that LCs from human skin express TLR1, -2, -5, -6, and -9, the cognate receptors for detection of specific bacteria-derived molecules. As compared with other TLR agonists, LCs acquired a more matured phenotype when activated by specific bacterial or synthetic TLR2 agonists. In addition, monocyte-derived Langerin+/CD1c+LCs (CD1c+MoLCs) secreted higher amounts of IL-6 and TNF-α by stimulation via TLR2 than by stimulation via TLR3, -4, -5, -8, and -9. In contrast to MoLCs, dendritic cells, generated from the same donor monocytes, were activated by agonists of TLRs other than TLR2 as well. Lipopeptides triggering TLR2 induced IL-1R-associated kinase-1 phosphorylation and migration toward the chemokines CCL19 and CCL21 in epidermal LCs and CD1c+MoLCs. Up-regulation of CD86, CD83, and CCR7, TNF-α and IL-6, and NF-κB activation and proliferation of CD4+T cells could be inhibited TLR2-specific blockage using antibodies prior to TLR2 activation. Application of anti-TLR1, anti-TLR6, and anti-TLR2 indicated an exclusive role of TLR2 in IL-6 induction in human LCs. Collectively, our results show that TLR2 expressed by LCs mediates inflammatory responses to lipopeptides, which implicates a central role in sensing pathogens in human skin.
Correction of tibial deformity in Paget’s disease using the Taylor spatial frame
Authors: Tsaridis E. , Sarikloglou S. , Papasoulis E. , Lykoudis S. , Koutroumpas I. , Avtzakis V.
Published: February 2008

A 64-year-old man presented with a severe deformity of the tibia caused by Paget’s disease and osteoarthritis of the ipsilateral knee. Total knee replacement required preliminary correction of the tibial deformity. This was successfully achieved by tibial osteotomy followed by distraction osteogenesis using the Taylor spatial frame. The subsequent knee replacement was successful, with no recurrence of deformity.
The effect of an unplanned excision of a soft-tissue sarcoma on prognosis
Authors: Chandrasekar C. R. , Wafa H. , Grimer R. J. , Carter S. R. , Tillman R. M. , Abudu A.
Published: February 2008

We investigated whether our policy of routine re-excision of the tumour bed after an unplanned excision of a soft-tissue sarcoma was justified.

Between April 1982 and December 2005, 2201 patients were referred to our hospital with the diagnosis of soft-tissue sarcoma, of whom 402 (18%) had undergone an unplanned excision elsewhere. A total of 363 (16.5%) were included in this study. Each patient was routinely restaged and the original histology was reviewed. Re-excision was undertaken in 316 (87%). We analysed the patient, tumour and treatment factors in relation to local control, metastasis and overall survival.

Residual tumour was found in 188 patients (59%). There was thus no residual disease in 128 patients of whom 10% (13) went on to develop a local recurrence. In 149 patients (47%), the re-excision specimen contained residual tumour, but it had been widely excised. Local recurrence occurred in 30 of these patients (20%). In 39 patients (12%), residual tumour was present in a marginal resection specimen. Of these, 46% (18) developed a local recurrence. A final positive margin in a high-grade tumour had a 60% risk of local recurrence even with post-operative radiotherapy.

Metastases developed in 24% (86). The overall survival was 77% at five years. Survival was related to the grade of the tumour and the finding of residual tumour at the time of re-excision.

We concluded that our policy of routine re-excision after unplanned excision of soft-tissue sarcoma was justified in view of the high risk of finding residual tumour.
The Effect of Temporary Amygdala Inactivation on Extinction and Reextinction of Fear in the Developing Rat: Unlearning as a Potential Mechanism for Extinction Early in Development
Authors: Kim Jee Hyun , Richardson Rick
Published: February 2008

It is well accepted that fear extinction does not cause erasure of the original conditioned stimulus (CS)–unconditioned stimulus association in the adult rat because the extinguished fear often returns (e.g., renewal and reinstatement). Furthermore, extinction is NMDA and GABA dependent, showing that extinction involves new inhibitory learning. We have recently observed each of these extinction-related phenomena in 24-d-old but not in 17-d-old rats. These results suggest that different neural processes mediate extinction early in development. However, the neural processes underlying extinction in the developing rat are unknown. Therefore, the present study investigated amygdala involvement in extinction and reextinction during development. In experiment 1, temporary inactivation of the amygdala (using bupivacaine, a sodium channel modulator) during extinction training impaired extinction of conditioned fear in 17- and 24-d-old rats. In experiment 2, 17- and 24-d-old rats were conditioned, extinguished, and then reconditioned to the same CS. After reconditioning, the CS was reextinguished; at this time, some rats at each age had their amygdala temporarily inactivated. Reextinction was amygdala independent in 24-d-old rats, as previously shown in adult rats. However, reextinction was still amygdala dependent in 17-d-old rats. In Experiment 3, the age at conditioning, reconditioning, reextinction, and test was held constant, but the age of initial extinction varied across groups; reextinction was found to be amygdala independent if initial extinction occurred at 24 d of age but amygdala dependent if it occurred at 17 d of age. Consistent with previous findings, these results show that there are fundamental differences in the neural mechanisms of fear extinction across development.
Chronic Exposure to Nerve Growth Factor Increases Acetylcholine and Glutamate Release from Cholinergic Neurons of the Rat Medial Septum and Diagonal Band of Broca via Mechanisms Mediated by p75NTR
Authors: Huh Carey Y. L. , Danik Marc , Manseau Frédéric , Trudeau Louis-Eric , Williams Sylvain
Published: February 2008

Basal forebrain neurons play an important role in memory and attention. In addition to cholinergic and GABAergic neurons, glutamatergic neurons and neurons that can corelease acetylcholine and glutamate have recently been described in the basal forebrain. Although it is well known that nerve growth factor (NGF) promotes synaptic function of cholinergic basal forebrain neurons, how NGF affects the newly identified basal forebrain neurons remains undetermined. Here, we examined the effects of NGF on synaptic transmission of medial septum and diagonal band of Broca (MS-DBB) neurons expressing different neurotransmitter phenotypes. We used MS-DBB neurons from 10- to 13-d-old rats, cultured on astrocytic microislands to promote the development of autaptic connections. Evoked and spontaneous postsynaptic currents were recorded, and neurotransmitters released were characterized pharmacologically. We found that chronic exposure to NGF significantly increased acetylcholine and glutamate release from cholinergic MS-DBB neurons, whereas glutamate and GABA transmission from noncholinergic MS-DBB neurons were not affected by NGF. Interestingly, the NGF-induced increase in neurotransmission was mediated by p75NTR. These results demonstrate a previously unidentified role of NGF and its receptor p75NTR; their interactions are crucial for cholinergic and glutamatergic transmission in the septohippocampal pathway.
Linoleic acid induces Ca2+-induced inactivation of voltage-dependent Ca2+ currents in rat pancreatic β-cells
Authors: Feng Dan-Dan , Zhao Yu-Feng , Luo Zi-Qiang , Keating Damien J , Chen Chen
Published: February 2008

Free fatty acids (FFAs) regulate insulin secretion in a complex pattern and induce pancreatic β-cell dysfunction in type 2 diabetes. Voltage-dependent Ca2+ channels (VDCC) in β-cells play a major role in regulating insulin secretion. The aim of present study is to clarify the action of the FFA, linoleic acid, on VDCC in β-cells. The VDCC current in primary cultured rat β-cells were recorded under nystatin-perforated whole-cell recording configuration. The VDCC was identified as high-voltage-gated Ca2+ channels due to there being no difference in current amplitude under holding potential between −70 and −40 mV. Linoleic acid (10 μM) significantly inhibited VDCC currents in β-cells, an effect which was fully reversible upon washout. Methyl-linoleic acid, which does not activate G protein coupled receptor (GPR)40, neither did alter VDCC current in rat β-cells nor did influence linoleic acid-induced inhibition of VDCC currents. Linoleic acid-induced inhibition of VDCC current was not blocked by preincubation of β-cells with either the specific protein kinase A (PKA) inhibitor, H89, or the PKC inhibitor, chelerythrine. However, pretreatment of β-cells with thapsigargin, which depletes intracellular Ca2+ stores, completely abolished linoleic acid-induced decrease in VDCC current. Measurement of intracellular Ca2+ concentration ([Ca2+]i) illustrated that linoleic acid induced an increase in [Ca2+]i and that thapsigargin pretreatment inhibited this increase. Methyl-linoleic acid neither did induce increase in [Ca2+]i nor did it block linoleic acid-induced increase in [Ca2+]i. These results suggest that linoleic acid stimulates Ca2+ release from intracellular Ca2+ stores and inhibits VDCC currents in rat pancreatic β-cells via Ca2+-induced inactivation of VDCC.
Towards the semantic extraction of digital signatures for librarian image‐identification purposes
Authors: Poulos Marios , Bokos George , Vaioulis Fotios
Published: February 2008

In study we attempt to solve the problem of determining how authentic published images on the Internet are, and to what degree they may be identified by comparison to the original image. The technique proposed aims to serve the new requirements of libraries. One of these is the development of computational tools for the control and preservation of intellectual property such as digital objects, and especially of digital images. For this purpose, this article proposes the use of a serial number extracted using a previously tested semantic‐properties method. This method, based on the multilayers of a set of arithmetic points, assures the following two properties: the uniqueness of the final extracted number, and the semantic dependence of this number on the image used as the method's input. The major advantage of this method is that it can serve as the authentication for a published image or detect partial modifications to a reliable degree. Also, it requires the better of the known hash functions that the digital‐signature schemes use, and produces alphanumeric strings for checking authenticity and the degree of similarity between an unknown image and an original image. As an example of a possible application, this article suggests that this method could be incorporated into the well‐known DOI system in order to provide a reliable tool for identification and comparison of digital images.
Functional analysis skills training for residential caregivers
Authors: Phillips Katrina J. , Mudford Oliver C.
Published: February 2008

Functional analysis is the most effective assessment for identifying the maintaining contingencies of aberrant behavior. However, it is suggested that functional analyses are not conducted regularly due to the level of skill required. A multiple baseline design across participants was used to assess if four residential caregivers, with limited experience with applied behavior analysis, could be trained to implement the standard analog functional analysis conditions. The training consisted of a lecture, written information, modeling, rehearsal, and feedback. Results showed that all participants attained percentage correct responding scores above 95% on three consecutive trials following training. One caregiver showed positive generalization of skills to the assessment of another behavioral topography. The result of this study provides further evidence that lay individuals can be trained to assist in conducting functional analyses. Copyright © 2008 John Wiley & Sons, Ltd.
The study of the lipophilicity of α‐(4‐phenylpiperazin‐1‐yl)‐γ‐phthalimidobutyramides using chromatographic and computational methods
Authors: Malawska Barbara , Kulig Katarzyna , Bucki Adam , Zbek Pawel , Wieckowska Anna
Published: February 2008

The lipophilicity of the series of α‐(4‐phenylpiperazin‐1‐yl)‐γ‐phthalimido‐butyramides (1–8) has been investigated. Several methods, like reversed‐phase thin‐layer chromatography and high‐performance liquid chromatography using reversed‐phase RP18 and IAM.DD2 columns, were applied to determine RMO, log k0 and log k0IAM factors. The RP‐TLC investigations were performed in mixtures of acetone–water and acetonitrile–water. For RP‐HPLC method mixtures of acetonitrile, water and 0.01% TFA were used as the mobile phases while for IAM.DD2 investigations mixtures of acetonitrile and water were applied. The partition coefficients of compounds (1–8) were also calculated with the Pallas and CAChe programs. All the obtained data, both from experimental methods and computational calculations, were compared and a suitable conclusion was reached. Copyright © 2008 John Wiley & Sons, Ltd.
Ein Radio aus einem einzigen Nanoröhrchen
Authors: Welter Kira
Published: February 2008

Ende des 19. Jahrhunderts wurde die Radiotechnik entwickelt – eine Technik, die unsere Zivilisation stark beeinflusst hat. Die 30er Jahre gelten als “goldenes Zeitalter” des Radios, denn der Hörfunk war damals das Informations‐ und Unterhaltungsmedium schlechthin. Doch die ersten Radioapparate waren riesig und nahmen viel Platz weg. Heute ist es möglich, einen Radioempfänger auf engstem Raum zu platzieren. Die Ein‐Chip‐Radios sind die Basis für moderne Mobiltelefone, drahtlose Computernetze oder GPS‐Geräte (global‐positioning system). Die neueste Entwicklung ist aber das “Nanotube‐Radio”, das auf einem einzigen Kohlenstoff‐Nanoröhrchen (CNT=carbon nanotube) basiert und etwa 19 Größenordnungen – also zehn Trillionen Mal – kleiner ist als ein typisches Gerät aus den 30er Jahren.
Synthesis of Angularly Fused Carbocycles via Tandem Radical Cyclization of α‐Carbonyl Radicals
Authors: Prakash Chandran , Mohanakrishnan Arasambattu K.
Published: February 2008

An α‐carbonyl radical cyclization approach towards the synthesis of angularly fused tricyclic systems is described. On reduction with tributyltin hydride, bromo ketones yield a α‐carbonyl radical that undergoes successive 5‐exo‐dig/trig cyclizations, resulting in two or four contiguous stereocenters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
An efficient approach to texture‐based image retrieval
Authors: Hejazi Mahmoud R. , Ho Yo‐Sung
Published: February 2008

In this article, we present an efficient approach for image retrieval based on the textural information of an image, such as orientation, directionality, and regularity. For this purpose, we apply the nonlinear modified discrete Radon transform to estimate these visual contents. We then utilize texture orientation to construct the rotated Gabor transform for extraction of the rotation‐invariant texture feature. The rotation‐invariant texture feature, directionality, and regularity are the main features used in the proposed approach for similarity assessment. Experimental results on a large number of texture and aerial images from standard databases show that the proposed schemes for feature extraction and image retrieval significantly outperform previous works, including methods based on the MPEG‐7 texture descriptors. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 295–302, 2007
Endothelial cells derived from circulating progenitors as an effective source to functional endothelialization of NaOH‐treated poly(ε‐caprolactone) films
Authors: Serrano M. Concepcion , Pagani Raffaella , Ameer Guillermo A. , Vallet‐Regí Maria , Portolés M. Teresa
Published: February 2008

Biomaterials have been widely used to prepare synthetic vascular grafts over the past thirty years, but the inherent thrombogenicity of their surface can lead to graft failure. Endothelial progenitor cells (EPC) are circulating premature cells able to differentiate in either myocardial or endothelial cells (EC). The therapeutic potential of these cells and its easy obtaining technique are important reasons why these cells could be used to improve the performance of vascular grafts. In this study, two different stages of differentiation of EC derived from EPC (EC1and EC2) were characterized and cultured on poly(ε‐caprolactone) (PCL) films treated with NaOH(PCL‐NaOH). We investigated by immunolabeling the expression of CD31, von Willebrand factor (vWF), and endothelial nitric oxide synthase (eNOS) in these cells during the differentiation process. The proliferation, cell cycle, and mitochondrial function of EC2cultured on PCL‐NaOH were evaluated at different times. The effect of this biomaterial on the nitric oxide (NO) content was also measured. The mature EC obtained from circulating progenitor cells (EC2) showed an appropriate growth and functionality on NaOH‐treated films. They conserved their capacity to define vessel‐like structures in culture and increased their basal NO production. These results underline the potential usefulness of these EC2to get a functional endothelialization of polymers with applications in vascular tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Spray‐dried lipid‐hyaluronan‐polymethacrylate microparticles for drug delivery in the peritoneum
Authors: Domnina Yuliya A. , Yeo Yoon , Tse Julie Y. , Bellas Evangelia , Kohane Daniel S.
Published: February 2008

Application of controlled release technology to the peritoneum would allow for sustained drug levels. However, some polymeric systems either create adhesions, or rapidly exit the peritoneum; neither result is desirable. Here we have produced particles based on sphyngomyelin, a phospholipid that occurs naturally in the peritoneum, along with hyaluronic acid and the polymethacrylate Eudragit E100 (to modulate drug release). Particles with a low proportion of E100 (5% (w/w); “high SPM”) release albumin rapidly over 2 days, then more slowly; increasing the E100 to 20% (w/w; high “E100”) slowed drug release markedly. When injected in the murine peritoneum, high SPM particles were disseminated as free particles, without forming collections. There was a mild inflammatory response but no formation of adhesions. High E100 particles formed collections in all animals, with an intense inflammatory response. Even so, there were very few adhesions. These results suggest that microparticulate formulations can be produced that have acceptable drug‐releasing properties and are suitable for use in the peritoneum from the standpoint of biocompatibility. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Effect of scaffold architecture and pore size on smooth muscle cell growth
Authors: Lee Min , Wu Benjamin M. , Dunn James C. Y.
Published: February 2008

Tissue engineering has the potential to replace damaged tissues and organs. Diffusion limitation of cell growth in three‐dimensional (3D) scaffolds is a significant constraint in most tissue engineering applications. This study describes a scaffold architecture that improves mass transfer. Scaffolds with three different geometries of villi architecture (0.5, 1, 0.5; 0.5, 1, 1; 1, 1, 1 mm; villus diameter, height, intervillus spacing, respectively) were fabricated by indirect 3D printing technique. The ability of these scaffolds to support smooth muscle cell growth was investigated in vitro. Smooth muscle cells attached to the scaffolds uniformly after 1 day of culture, and the cell density in the scaffold with small villi feature (0.5 mm) was significantly higher as compared to that for the scaffold with large villi features (1 mm) after 14 days of culture. To evaluate the effect of scaffold pore size on cell growth, scaffolds with three different pore size ranges (50–100, 100–150, and 150–200 μm) were fabricated by the solvent casting and particulate leaching technique. Scaffold pore size did not significantly affect cell growth after 14 days of culture. Optimization in the architectural design of scaffolds provides an alternative method to improve diffusion limitation in the 3D constructs. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Granulocyte colony‐stimulating factor administration alters femoral biomechanical properties in C57BL/6 mice
Authors: Wu Yii‐Der , Chien Chi‐Hui , Chao Yuh J. , Hamrick Mark W. , Hill William D. , Yu Jack C. , Li Xiaodong
Published: February 2008

The clinical application of G‐CSF is broadening. In addition to treating neutropenia and in bone marrow transplants, it is now being considered for functional recovery after myocardial infarction and stroke. It is thus very important that the effects of extended G‐CSF administration on the skeleton are investigated. To simulate this potential clinical use of G‐CSF in postmyocardial infarction or cerebral vascular accident, a 2‐week course of administration was selected. Ten C57BL/6 mice at 22 weeks of age were given intraperitoneal injection of saline, and another nine of the same age were given G‐CSF. Four weeks later, femurs were harvested and three‐point‐bend tests were performed until fracture. From the load‐displacement curve recorded during the test, the stiffness, Young's modulus, fracture strength of the bone, fracture energy, and the total energy to break the femur were determined. The test data show that mice treated with G‐CSF have significantly lower modulus in their femurs when compared to the controlled mice treated with saline. The stiffness demonstrates the largest decrease, by as much as 25%. As its clinical use increases, G‐CSF effects on the mechanical properties of the skeleton become increasingly more important because many of these diseases occur in older patients with already compromised skeleton by osteopenia or osteoporosis. How G‐CSF administration achieves these alterations in skeletal biomechanical properties is unclear. Although the current findings confirm its known temporary catabolic effects on bone homeostasis, it also suggests that a transient state of higher bone compliance following the end of G‐CSF administration can be achieved that may have clinical benefits. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
The in situ synthesis of biphasic calcium phosphate scaffolds with controllable compositions, structures, and adjustable properties
Authors: Guo Dagang , Xu Kewei , Han Yong
Published: February 2008

In this study, biphasic calcium phosphate (BCP) porous scaffolds with controllable phase compositions, controllable macropore percentages, and thus adjustable properties were in situ prepared by sintering a series of composites consisted of calcium phosphate cement (CPC) and porous resin negative mold made from rapid prototyping (RP) technique. The CPC pastes were formed by mixing a powder mixture of tetracalcium phosphate and anhydrous dicalcium phosphate with liquid phase of diluted phosphate acid solution. Results show that the phase composition was easily adjustable by controlling both weight ratio of the powder mixture to the liquid phase (P/L) and concentration of the liquid phase. The macropore structure of the BCP scaffold can be regulated by using different RP negative molds. Through in vitro compressive strength (CS) and immersion tests, it was demonstrated that both macropore percentage and phase composition played important roles in the CS and also the dissolving rates of the scaffolds. As the macropore percentage of the scaffold increased, its CS decreased but the dissolving rate increased; also, as the weight ratio of hydroxyapatite to tricalcium (HA/TCP) in the scaffold increased, the CS first increased and then decreased but the dissolving rate uniformly decreased. The CS values of the BCP scaffolds with a HA/TCP weight ratio of 59:41 were 5.84 ± 1.16 MPa for a total porosity of ∼67.67% containing a macropore percentage of 30%, and 3.34 ± 0.79 MPa for a total porosity of ∼70.90% containing a macropore percentage of 50%, respectively, comparable to the corresponding levels of human cancellous bone (2–12 MPa). © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Clinical hospital medicine fellowships: Perspectives of employers, hospitalists, and medicine residents
Authors: Goodman Philip H. , Januska Andrius
Published: February 2008

BACKGROUND

Clinical hospital medicine fellowships could accelerate the acquisition of increasingly demanding skills while enhancing esteem among subspecialty peers. We sought to determine whether medicine residents perceived such fellowships as relevant and would be willing to forgo substantial income during the training period, in the context of the perspectives of employers and practicing hospitalists.

DESIGN

A series of 3 tandem nationwide cross‐sectional surveys conducted over the Internet during late 2005 and early 2006.

METHODS

Survey I was sent to 195 hospitalist employers identified through filtering classified advertisements. Survey II (containing Survey I results) was E‐mailed by the Society of Hospital Medicine to its practicing hospitalists members. Survey III (containing results of the first 2 surveys) was E‐mailed to U.S. internal medicine program directors for forwarding to their residents.

RESULTS

Two‐thirds of 103 employers would offer either a signing bonus or a starting salary increase of at least $10,000 to fellowship graduates (more than 20% would pay at least $20,000 more in the salary). Based on a median experience of 8 years, 91% of 101 practicing hospitalists beleived that clinical fellowship could at least possibly be a favorable career move, with 58% recommending it as being a probably or strongly favorable career move. Of 279 categorical medicine residents, 44% were considering a hospital medicine career, of whom 57% would consider doing a year of clinical fellowship training if available.

CONCLUSIONS

This study reveals a potentially unmet demand for clinical hospital medicine fellowship training. Further determination of need and related curricular development could be addressed under the leadership of national hospital medicine educational organizations. Journal of Hospital Medicine 2008;3:28–34. © 2008 Society of Hospital Medicine.
Peculiarities of friction in auxetic composites
Authors: Shilko S. V. , Petrokovets E. M. , Pleskachevsky Yu. M.
Published: February 2008

The adaptive mode of friction has been studied in the form of a self‐locking effect at contact deformation of isotropic and anisotropic auxetic materials featuring a negative Poisson's ratio. The effect infers that the bearing capacity of the joint raises with increasing shearing load. The stress state parameters were determined for normal indentation and compression with shear contact interaction. The contact interactions were analyzed by the finite element method for various contact profiles. Poisson's ratio was varied within the theoretically acceptable for the isotropic elastic medium values. The analogous calculations were performed for a joint with a deformed element made of anisotropic auxetic composite whose reinforcement angle was varied as a factor of elastic constants. The nonlinear dependencies of the maximum pressure, tangential stress and slippage were obtained as a function of Poisson's ratio (in the isotropic case) and reinforcement angle of the composite material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
XPS study of Fe(II)Fe(III) (oxy)hydroxycarbonate green rust compounds
Authors: Mullet Martine , Khare Varsha , Ruby Christian
Published: February 2008

The oxidation behaviour of Fe(II)Fe(III) hydroxysalt green rust (GR) compounds was investigated using XPS. Stoichiometric GR(CO32−), i.e. Fe(II)4Fe(III)2(OH)12CO33H2O was prepared by co‐precipitating Fe(II) and Fe(III) ions in carbonate‐containing solution under an inert atmosphere. Fast oxidation of stoichiometric GR(CO32−) by hydrogen peroxide in aqueous medium resulted in GR(CO32−)* of various composition, i.e. Fe(II)6(1−x)Fe(III)6xO12H2(7−3x)CO3 with 1/3 ≤ x ≤1, where x is the Fe(III) molar fraction [Fe(III)]/[Fe(total)] of positively charged hydroxide sheets. The Fe(2p3/2) spectra of GRs of various composition were well fitted using Gupta and Sen multiplet peaks and additional broad satellite and surface features. The oxidation of Fe(II) in the GR structure is accompanied by deprotonation of hydroxyl groups as evidenced by the O(1s) spectra. The deprotonation of the hydroxyl groups compensated for the presence of excess positive charge that resulted from the oxidation of Fe(II) in the GR structure. In addition, the fully ferric GR(CO32−)* at x = 1 was coated on a sand substrate and the quality of the GR coating was investigated by XPS imaging. Copyright © 2008 John Wiley & Sons, Ltd.
A generalized log‐rank test for interval‐censored failure time data via multiple imputation
Authors: Huang Jinlong , Lee Chinsan , Yu Qiqing
Published: February 2008

Interval‐censored (IC) failure time data often occur in follow‐up studies where subjects can only be followed periodically and the failure time can only be known to lie in an interval. In this paper we propose a modified log‐rank test for the problem of comparing two or more IC samples. Our log‐rank statistic and covariance matrix are calculated by a multiple imputation technique. Through simulation studies, we find that the performance of the proposed test is comparable to that of the test proposed by Finkelstein (Biometrics1986;42(4):845–854) and is better than that of the two existing log‐rank type tests proposed by Sun (Lifetime Data Anal. 2001;7:363–375) and Zhao and Sun (Stat. Med. 2004;23(10):1621–1629) due to the differences in the method of multiple imputation and the covariance matrix estimation. Our covariance matrix estimator is similar to the estimator used by Follmannet al. (Biometrics2003;59:420–429) for clustered data. The proposed method is illustrated by means of an example involving patients with breast cancer. Copyright © 2008 John Wiley & Sons, Ltd.
The effect of duloxetine on urethral sphincter morphology
Authors: Duckett J. , Patil A. , Aggarwal I.
Published: February 2008

Objectives

This was a pilot study to identify whether a course of duloxetine had any effect on urethral sphincter morphology.

Methods

Fifteen women with urodynamic stress incontinence were treated with duloxetine. The pretreatment condition of the bladder was assessed with the Patient Global Impression of Severity scale. A transperineal ultrasound scan was performed before therapy and again after 4–8 weeks of treatment. The urethral length and the width of the hypoechogenic core (longitudinal smooth muscle, vascular plexus and urothelium) were assessed.

Results

Baseline incontinence symptoms were moderate or severe in 87% of women and an improvement following treatment was reported in 80% of women. Poor views were obtained of the striated muscle. There was a statistically significant increase in the mean width of the hypoechogenic core of the urethra from 5.0 mm to 6.3 mm (P < 0.01). There was no statistically significant change in the length of the urethra (mean 29.4 mm before and 28.0 mm after treatment).

Conclusions

Duloxetine appears to result in an alteration of the smooth muscle component of the urethral sphincter. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
The effect of fetoscopic laser therapy on fetal cardiac size in twin–twin transfusion syndrome
Authors: Sueters M. , Middeldorp J. M. , Vandenbussche F. P. H. A. , Teunissen K. A. , Lopriore E. , Kanhai H. H. H. , Le Cessie S. , Oepkes D.
Published: February 2008

Objectives

To evaluate the influence of fetoscopic laser therapy on fetal cardiac size in monochorionic twins complicated by twin–twin transfusion syndrome (TTTS).

Methods

In a longitudinal, prospective study, we assessed fetal cardiac size sonographically in monochorionic diamniotic twins with TTTS treated by laser therapy and in monochorionic twins without TTTS. The fetal cardiothoracic ratio (cardiac circumference divided by thoracic circumference) of TTTS twins was determined within 24 h before, 12–24 h after and 1 week after laser treatment, and from then on every 2–4 weeks until birth. TTTS twins were classified into Quintero Stages 1–2 (n = 18) and Stages 3–4 (n = 16), and measurements were compared with biweekly measurements of non‐TTTS monochorionic twins matched for gestational age (n = 38). Cardiomegaly was defined as a cardiothoracic ratio above the 97.5th percentile.

Results

Before laser treatment, cardiomegaly was observed in 44% (8/18) and 50% (8/16) of recipients in Quintero Stages 1–2 and Stages 3–4, respectively. Cardiomegaly occurred in none of the donors before treatment. After laser treatment, cardiomegaly was observed in 76% (13/17) and 50% (7/14) of recipients in Stages 1–2 and Stages 3–4, respectively, and in 17% (3/18) and 13% (2/15) of donors in Stages 1–2 and Stages 3–4, respectively. Cardiomegaly was present in 18% (7/38) and 8% (2/25) of non‐TTTS monochorionic twins and singletons. After laser therapy, the cardiothoracic ratio of recipients in Stages 1–2 and Stages 3–4 was not significantly changed (P = 0.34 and P = 0.67, respectively). The cardiothoracic ratio of donors in Stages 1–2 and Stages 3–4 was increased compared with that before laser therapy (P = 0.0002 and P = 0.005, respectively). Cardiothoracic ratios of non‐TTTS monochorionic twins were not significantly different from our reference range in singletons throughout gestation, and were smaller than those in both recipients and donors after laser therapy.

Conclusions

TTTS recipients show cardiomegaly before as well as after fetoscopic laser therapy for TTTS. Donors develop cardiomegaly only after laser treatment. Our findings emphasize the significant effect of TTTS and fetoscopic laser therapy on the fetal heart of both recipient and donor twins. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Effects of carrot and tomato juice consumption on faecal markers relevant to colon carcinogenesis in humans
Authors: Schnäbele Kerstin , Briviba Karlis , Bub Achim , Roser Silvia , Pool-Zobel Beatrice L. , Rechkemmer Gerhard
Published: February 2008

High intakes of carotenoid-rich fruits and vegetables are associated with a reduced risk of various cancers including colon cancer. A human intervention study with carrot and tomato juice should show whether a diet rich in carotenoids, especially high in β-carotene and lycopene, can modify luminal processes relevant to colon carcinogenesis. In a randomised cross-over trial, twenty-two healthy young men on a low-carotenoid diet consumed 330 ml tomato or carrot juice per d for 2 weeks. Intervention periods were preceded by 2-week depletion phases. At the end of each study period, faeces of twelve volunteers were collected for chemical analyses and use in cell-culture systems. Consumption of carrot juice led to a marked increase of β-carotene and α-carotene in faeces and faecal water, as did lycopene after consumption of tomato juice. In the succeeding depletion phases, carotenoid contents in faeces and faecal water returned to their initial values. Faecal water showed high dose-dependent cytotoxic and anti-proliferative effects on colon adenocarcinoma cells (HT29). These effects were not markedly changed by carrot and tomato juice consumption. Neither bile acid concentrations nor activities of the bacterial enzymes β-glucosidase and β-glucuronidase in faecal water changed after carrot and tomato juice consumption. Faecal water pH decreased only after carrot juice consumption. SCFA were probably not responsible for this effect, as SCFA concentrations and profiles did not change significantly. In summary, in the present study, 2-week interventions with carotenoid-rich juices led only to minor changes in investigated luminal biomarkers relevant to colon carcinogenesis.
Three‐dimensional interference test interpretation in a fractured aquifer using the Pilot Point Inverse Method
Authors: Lavenue Marsh , de Marsily Ghislain
Published: February 2008

A geostatistical conditional simulation routine that employs both parametric and nonparametric geostatistics is coupled to the pilot point inverse method to simulate the spatial distribution of conductivities in a dolomitic aquifer which is fractured in some areas and unfractured in others. An inversion is then conducted to obtain the conductivities within the fractured and nonfractured parts of the aquifer to match interference data from a series of three‐dimensional pumping tests for an ensemble of 100 conditional simulations. The calibrated and predicted drawdowns match the observed drawdowns well. A comparison to the transmissivity interpreted from a single‐well pumping test compared very well to the geometric mean transmissivity calculated from the calibrated realizations in this study. The results from this study indicate that conditioning the conductivity fields to the geologic facies data, in this case fractured‐unfractured categorical data, as well as to ample transient hydraulic data can lead to robust groundwater flow models which can adequately predict the response to other hydraulic interference tests.
Probabilistic model for the estimation ofTyear flow duration curves
Authors: Iacobellis Vito
Published: February 2008

A flow duration curve (FDC) is the relationship between any given discharge value and the percentage of time that this discharge is exceeded. It represents the relationship between magnitude and frequency of streamflow discharges. In this paper, a new methodology for the evaluation of the flow duration curve with assigned return periodTis proposed. The procedure is based on the use of distributions bounded by the interval 0 to 1 and exploits the properties of the beta and complementary beta (CB) distributions. The proposed model, called “EtaBeta,” accounts for the interannual variability of the FDC using the distributions of annual minimum daily flow and total annual flow. The intra‐annual variability is described by the CB distribution, which (like the beta distribution) has two parameters that characterize the shape of the distribution and in particular of its tails. The model is applied to basins of southern Italy characterized by strong seasonality and highly variable discharge. The results show good performance in terms of the model's ability to represent the analyzed flow duration curves of discharge data even in low‐flow conditions. The EtaBeta model also offers interesting possibilities for use in regional analysis.
Large‐scale thin‐skinned tectonics in the eastern boundary of the Bohemian Massif
Authors: Cizek Pavel , Tomek Cestmir
Published: February 2008

Two new seismic reflection profiles and a deep borehole reveal thin‐skinned thrusting on the easternmost part of the Rheno‐Hercynian zone of the Variscan belt of Europe. Above Precambrian Brunnia basement the profiles show three different seismic zones within the compressed Palaeozoic sedimentary section. The borehole data suggest that the lower zone is a deformed “paraautochthonous” Brunnia basement covered by Upper Devonian and Lower Carboniferous shelf carbonates with numerous local overthrusts. This zone is overthrust by the uppermost seismic zone of Lower Carboniferous Culm flysch wedge and in the west by the eastward dipping zone. This intervening seismic zone on the east end of the profiles is a foreland dipping thrust sheet of another Culm flysch complex (mainly Horni Benesov Formation), or seismic crocodiles in the sense of Meissner (1989). Inverted metamorphism between the Culm flysch and the Brunnia shelf sequences encountered in the well Potstat‐1, and strong slaty cleavage in the intervening zone, suggests that the upper zone is allochthonous, heaving been thrust from deeper levels tens of kilometres eastward over carbonates. Imbrication of the carbonates as part of the footwall suggest relatively strong coupling between the Palaeozoic sediments and underlying basement at the time of thrusting.