bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐resolution NMR imaging of paramagnetic liposomes targeted to a functionalized surface
Authors: Huinink H.P. , Sanders H.M.H.F. , Erich S.J.F. , Nicolay K. , Strijkers G.J. , Merkx M. , Adan O.C.G 
Published: April 2008

AbstractA major application of molecular MR imaging is receptor mapping of cells lining blood vessels with targeted contrast agents. Since these agents accumulate at interfaces, knowledge of their influence on the relaxation process in this specific configuration is a prerequisite for understanding their working principle. A methodology is presented to study the influence of targeted contrast agents on surface relaxation in vitro. Paramagnetic liposomes attached to a functionalized surface were studied with high‐resolution NMR imaging. The surface was prepared by covering a solid substrate with a layer of collagen. Paramagnetic liposomes were targeted to this surface by functionalizing the liposomes with collagen adhesion protein CNA‐35. With a saturation‐recovery sequence, 1D magnetization profiles with a resolution of 5 μm were measured in water in contact with the surface. Analytical predictions, obtained with the Bloch–Torrey equation, perfectly agreed with the experimental data. Therefore, the magnitude of the surface relaxation rate could be determined from the measurements without any assumption. By using the relaxivity of liposome solutions the surface coverage by liposomes could be estimated. With the presented methodology the behavior of Gd‐based targeted contrast agents at biological interfaces can be studied in vitro. Their influence on relaxation processes can be characterized and quantified. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Fast prospective registration of in vivo MR images of trabecular bone microstructure in longitudinal studies
Authors: Rajapakse Chamith S. , Magland Jeremy F. , Wehrli Felix W. 
Published: April 2008

AbstractIn micro‐MRI studies of trabecular bone designed to evaluate structural changes in response to intervention, follow‐up scan volumes do not typically align exactly with the baseline scan volumes due to the orientation and placement of the anatomic location, here the distal tibia, relative to the scanner coordinates. Failure of accurate registration of the follow‐up to the baseline images introduces errors due to the inherent anisotropy in the trabecular network and anisotropic voxel size. In this work it is shown that these limitations can be overcome by incorporating on‐line prospective registration into the data acquisition protocol. The technique is based on a short 3D localizer scan of 1 mm isotropic resolution prior to acquiring the high‐resolution images. During the follow‐up exam, localizer images are registered on‐site with an algorithm relying on a fast Fourier transform for maximizing the correlation between baseline and follow‐up localizers. Transformation parameters obtained in this manner are then fed into the scanner software so that the imaging slab for the high‐resolution follow‐up images is automatically positioned consistent with that of the baseline scan. Based on phantom and human subject studies it is shown that prospective registration yields very close matching between baseline and follow‐up imaging volumes. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Assessment of lipids in skeletal muscle by high‐resolution spectroscopic imaging using fat as the internal standard: Comparison with water referenced spectroscopy
Authors: Weis J. , Johansson L. , Ortiz‐Nieto F. , Ahlström H. 
Published: April 2008

AbstractThe main purpose of the study was to compare proton (1H) single‐voxel MR spectroscopy (MRS) with high‐spatial‐resolution spectroscopic imaging (MRSI) to determine the lipid content in human skeletal muscle. Unsuppressed water line was used as a concentration reference in the processing of single‐voxel spectra. The spectrum from yellow bone marrow with a 100% fat content and probe with the vegetable oil served as internal and external reference for high‐spatial‐resolution MRSI, respectively. Very good correlation was found between lipid concentrations measured by water referenced single‐voxel MRS and high‐spatial‐resolution MRSI with yellow bone marrow as the internal standard. Excellent correlation was found between total lipid concentrations estimated by high‐spatial‐resolution MRSI with vegetable oil as the external fat standard and yellow bone marrow as the internal reference. From comparison of single‐voxel MRS and MRSI approaches, it follows that relaxation correction of the reference water and methylene fat line is inevitable in processing the standard single‐voxel spectra. The high‐resolution MRSI approach is recommended to avoid the problem of relaxation corrections and enables using vegetable oil as the external fat standard. Magn Reson Med 59:1259–1265, 2008. © 2008 Wiley‐Liss, Inc.
Performance of a 200‐MHz cryogenic RF probe designed for MRI and MRS of the murine brain
Authors: Ratering David , Baltes Christof , Nordmeyer‐Massner Jurek , Marek Daniel , Rudin Markus 
Published: April 2008

AbstractA cryogenic 200‐MHz RF transmit/receive probe (CryoProbe) made of copper and designed for murine brain studies is described. The probe operates at 30K and its performance was compared to a home‐made surface coil of equal dimensions and a mouse head volume resonator, both operating at room temperature (RT). Since for small volumes of tissue interrogated (<5 mL) sample noise and thermal noise of the receiver are of comparable magnitude, considerable noise reduction can be achieved by cooling of the receiver system, e.g., using cold helium gas. The effect of temperature lowering on the signal‐to‐noise ratio (SNR) was assessed in phantom and in vivo murine brain studies using conventional MRI sequences (spin and gradient echo) and single voxel MR spectroscopy. Consistent sensitivity increases were observed for the CryoProbe. SNR increases by a factor ≥2 for the phantom experiments and by factors of 1.8 to 1.9 for in vivo experiments when compared to the RT surface coil for both MRI and MRS experiments. These results are in good agreement with estimated SNR gains for a circular surface coil probe cooled to 30K. The use of a cryogenic probe represents an economically attractive option to enhance the sensitivity in small animal MRI/MRS. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
A small‐strain overlay model
Authors: Benz T. , Vermeer P. A. , Schwab R. 
Published: April 2008

AbstractThe paper begins with a discussion of the phenomenon of small‐strain stiffness and presents the small‐strain overlay model, a simple model that takes into account the non‐linear stiffness of soils at small strains. The new model can enhance already established elastoplastic formulations for non‐linear stiffness variation at small strains in a similar way that intergranular strain enhances the hypoplastic model. The overlay model is driven by the material's strain history and only two additional material constants, both with clear physical meaning. Therefore, the proposed model is a step towards the incorporation of small‐strain stiffness into routine design. In this paper, the new small‐strain overlay model is formulated. Its ability to take into account the influence of various strain histories on soil stiffness is illustrated in several examples. Copyright © 2008 John Wiley & Sons, Ltd.
A model for pore‐fluid‐sensitive rock behavior using a weathering state parameter
Authors: Hickman R. J. , Gutierrez M. S. , De Gennaro V. , Delage P. 
Published: April 2008

AbstractChalk and other porous rocks are known to behave differently when saturated with different pore fluids. The behavior of these rocks varies with different pore fluids and additional deformation occurs when the pore fluid composition changes. In this article, we review the evidence that behavior in porous rocks is pore‐fluid‐dependent, present a constitutive model for pore‐fluid‐dependent porous rocks, and present a compilation of previously published data to develop quantitative relationships between various pore fluids and mechanical behavior. The model proposed here is based on a state parameter approach for weathering and has similarities to models previously proposed for weathering‐sensitive rocks in that the values for parameters that characterize material behavior vary as a function of weathering. Comparisons with published experimental data indicate that the model is capable of reproducing observed behavior of chalk under a variety of loading conditions and changes in pore fluid composition. Copyright © 2008 John Wiley & Sons, Ltd.
Lateral load distributions on grouped piles from dynamic pile‐to‐pile interaction factors
Authors: Chang Der‐Wen , Lin Bor‐Shiun , Cheng Shih‐Hao 
Published: April 2008

AbstractThe load distributions of the grouped piles under lateral loads acting from one side of the pile cap could be approximately modeled using the elasticity equations with the assumptions that the underground structure is rigid enough to sustain the loads, and only small deformations of the soils are yielded. Variations of the soil–pile interactions along the depths are therefore negligible for simplicity. This paper presents the analytical modeling using the dynamic pile‐to‐pile interaction factors for 2 × 2 and 2 × 3 grouped piles. The results were found comparative with the experimental and numerical results of other studies. Similar to others' findings, it was shown that the leading pile could carry more static loads than the trailing pile does. For the piles in the perpendicular direction with the static load, the loads would distribute symmetrically with the centerline whereas the middle pile always sustains the smallest load. For steady‐state loads with operating frequencies up to 30 Hz, the pile load distributions would vary significantly with the frequencies. It is interesting to know that designing the pile foundation needs to be cautioned for steady‐state vibrations as they are a problem of machine foundation. However, for transient loads or any harmonic loads acting upon relatively higher frequencies, the pile loads could be regarded as uniformly distributed. It is hoped that the numerical results of this paper will be helpful in the design practice of pile foundation. Copyright © 2008 John Wiley & Sons, Ltd.
Association between dense CADM1 promoter methylation and reduced protein expression in high‐grade CIN and cervical SCC
Authors: Overmeer RM , Henken FE , Snijders PJF , Claassen‐Kramer D , Berkhof J , Helmerhorst TJM , Heideman DAM , Wilting SM , Murakami Y , Ito A , Meijer CJLM , Steenbergen RDM 
Published: April 2008

AbstractWe previously showed that silencing of TSLC1, recently renamed CADM1, is functionally involved in high‐risk HPV‐mediated cervical carcinogenesis. CADM1 silencing often results from promoter methylation. Here, we determined the extent of CADM1 promoter methylation in cervical (pre)malignant lesions and its relation to anchorage‐independent growth and gene silencing to select a CADM1‐based methylation marker for identification of women at risk of cervical cancer. Methylation‐specific PCRs targeting three regions within the CADM1 promoter were performed on high‐risk HPV‐containing cell lines, PBMCs, normal cervical smears, and (pre)malignant lesions. CADM1 protein expression in cervical tissues was analysed by immunohistochemistry. All statistical tests were two‐sided. Density of methylation was associated with the degree of anchorage‐independent growth and CADM1 gene silencing in vitro. In cervical squamous lesions, methylation frequency and density increased with severity of disease. Dense methylation (defined as ≥ 2 methylated regions) increased from 5% in normal cervical samples to 30% in CIN3 lesions and 83% in squamous cell carcinomas (SCCs) and was significantly associated with decreased CADM1 protein expression (p < 0.00005). The frequency of dense methylation was significantly higher in ≥ CIN3 compared with ≤ CIN1 (p = 0.005), as well as in SCCs compared with adenocarcinomas (83% versus 23%; p = 0.002). Detection of dense CADM1 promoter methylation will contribute to the assembly of a valuable marker panel for the triage of high‐risk HPV‐positive women at risk of ≥ CIN3. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Chronic wound state exacerbated by oxidative stress in Pax6+/− aniridia‐related keratopathy
Authors: Ou J , Walczysko P , Kucerova R , Rajnicek AM , McCaig CD , Zhao M , Collinson JM 
Published: April 2008

AbstractHeterozygosity for the transcription factor PAX6 causes eye disease in humans, characterized by corneal opacity. The molecular aetiology of such disease was investigated using a Pax6+/− mouse model. We found that the barrier function of uninjured Pax6+/− corneas was compromised and that Ca2+–PKC/PLC–ERK/p38 signalling pathways were abnormally activated, mimicking a ‘wounded’ epithelial state. Using proteomic analysis and direct assay for oxidized proteins, Pax6+/− corneas were found to be susceptible to oxidative stress and they exhibited a wound‐healing delay which could be rescued by providing reducing agents such as glutathione. Pax6 protein was oxidized and excluded from the nucleus of stressed corneal epithelial cells, with concomitant loss of corneal epithelial markers and expression of fibroblast/myofibroblast markers. We suggest a chronic wound model for Pax6‐related corneal diseases, in which oxidative stress underlies a positive feedback mechanism by depleting nuclear Pax6, delaying wound healing, and activating cell signalling pathways that lead to metaplasia of the corneal epithelium. The study mechanistically links a relatively minor dosage deficiency of a transcription factor with potentially catastrophic degenerative corneal disease. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Peripherally inserted central venous catheters are a good option for prolonged venous access in children with cancer
Authors: Abedin Sarfraz , Kapoor Gauri 
Published: April 2008

AbstractBackgroundA long term venous access device is essential in children with malignancies for the safe administration of medication and to avoid repeated painful venipunctures. The advantage of peripherally inserted central venous catheters (PICC) over conventional central venous catheter (CVC) is easy bedside insertion without need for general anesthesia and theatre time. The purpose of this study was to evaluate our experience with PICCs particularly with regard to catheter life, reason for removal and complications in children suffering from various malignancies.ProcedureA retrospective analysis of all PICCs inserted in children with cancer was done with regard to the demographic data, catheter life, reason for removal, and complications. The latter two were evaluated in association with patient age, catheter days, and year of insertion.ResultsOf 127 catheters inserted in 127 children, median catheter life was 161 days with a total of 18,955 catheter days (for 124 patients, 3 lost to follow‐up). Elective removal occurred in 63/101 (62.4%) PICCs and removal due to complications resulted in a complication rate of 2.41 per 1,000 catheter days. The common reasons for catheter removal were suspected infection, breakage/leakage, dislodgement, phlebitis, and occlusion with rates of 1.27, 0.57, 0.31, 0.06, and 0.06 per 1,000 catheter days, respectively.ConclusionWe found PICC to be a convenient, cheap, safe, and reliable device for long term intravenous access in children with malignancies. This was possible with the help of dedicated catheter care nurses. Pediatr Blood Cancer 2008;51:251–255. © 2008 Wiley‐Liss, Inc.
Familial hemophagocytic lymphohistiocytosis in two brothers with X‐linked agammaglobulinemia
Authors: Schultz Kris Ann P. , Neglia Joseph P. , Smith Angela R. , Ochs Hans D. , Torgerson Troy R. , Kumar Ashish 
Published: April 2008

AbstractHemophagocytic lymphohistiocytosis (HLH) is often familial and is associated with high mortality. Primary (familial) HLH is known to occur in children with mutations in perforin, Munc13‐4, or syntaxin 11. We describe a case series of two brothers who developed HLH in the setting of X‐linked agammaglobulinemia (XLA, Bruton's disease) and adenovirus infection. Further studies revealed absence of Bruton's tyrosine kinase (BTK) protein expression and a novel BTK mutation. Pediatr Blood Cancer 2008;51:293–295. © 2008 Wiley‐Liss, Inc.
Neuropsychological outcome following intensity‐modulated radiation therapy for pediatric medulloblastoma
Authors: Jain Neelam , Krull Kevin R. , Brouwers Pim , Chintagumpala Murali M. , Woo Shiao Y. 
Published: April 2008

AbstractBackgroundCombined cisplatin chemotherapy and cranial irradiation for treatment of medulloblastoma in children can cause significant ototoxicity and impair cognitive function and quality of life. We have previously demonstrated the conformal technique of intensity‐modulated radiation therapy (IMRT) to reduce ototoxicity, however, it has been suggested that IMRT may increase risk of cognitive deficits compared to conventional radiation therapy (CRT). This study compared the impact of the two treatments on measures of neurocognitive functioning.ProcedureTwenty‐five pediatric patients with medulloblastoma were treated either with CRT or IMRT. In addition they received neurocognitive assessments to evaluate long‐term functional outcome. Statistical analyses between the two groups were conducted to compare levels and profiles of performance on tests not confounded with hearing loss.ResultsWhen compared to CRT, children treated with IMRT did not perform more poorly on any of the measures. Both groups' mean performance was significantly lower than published norms on several of the measures employed.ConclusionThe benefit of reduced ototoxicity with IMRT does not appear to be at the cost of a decline in nonverbal intellectual abilities, visual‐spatial skills, processing speed, or fine motor dexterity when compared to CRT in children with medulloblastoma. Pediatr Blood Cancer 2008;51:275–279. © 2008 Wiley‐Liss, Inc.
Effect of electron beam irradiation on physico–mechanical properties of wood flour–polyethylene composites
Authors: Younes M.M. , Abdel‐Rahman H.A. , Orabi W. , Ismail M.R. 
Published: April 2008

AbstractAgricultural lignocellulosic fiber (wood flour)‐waste was used to prepare composite materials through partial replacement of wood flour with low density polyethylene powder (LDPE) ranged from 10 to 20% by weight; these composites were made with and without electron beam irradiation (EB). The results obtained showed that, flexural strength, modulus of elasticity, modulus of rupture, and impact strength increase with increasing content of LDPE up to 20%. While, the percentages of thickness swelling and water absorption are decreased directly with increasing content of LDPE. Furthermore, the EB irradiation improves the physico‐mechanical properties of composite materials from 10 to 50 kGy. The results obtained are also confirmed by scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Preparation and shear properties of carbon nanotubes/poly(butyl methacrylate) hybrid material
Authors: Li Wen‐Hua , Chen Xiao‐Hua , Chen Chuan‐Sheng , Xu Long‐Shan , Yang Zhi , Wang Yan‐Guo 
Published: April 2008

AbstractComposites containing carbon nanotubes (CNTs) in a poly(butyl methacrylate) (PBMA) have been prepared by in situ polymerization. Scanning electron microscopy and high‐resolution transmission electron microscope showed that CNTs were well dispersed into PBMA matrix and wrapped with PBMA. The infrared spectrum illustrated that CNTs were covalently linked with PBMA through a CC bond. Owing to this covalent linkage, the composites had a better solubility in organic solvents and had higher thermal stability over pure PBMA. The direct shear testing showed strong mechanical behavior with up to 200% increase in Young's modulus. The possible strengthening mechanism was discussed. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
The influence of matrix viscosity and composition on the morphology, rheology, and mechanical properties of thermoplastic elastomer nanocomposites based on EPDM/PP
Authors: Naderi Ghasem , Lafleur Pierre G. , Dubois Charles 
Published: April 2008

AbstractThe morphological and rheological properties of thermoplastic elastomer nanocomposites (TPE nanocomposites) were studied using different viscosities of polypropylene (PP) and ethylene‐propylene‐diene monomer (EPDM) rubber content (20, 40, 60 wt%). The components, namely EPDM, PP, Cloisite 15A, and maleic anhydride‐modified PP as compatibilizer, were compounded by a one‐step melt mixing process in a laboratory internal mixer. The structure of the nanocomposites was characterized with X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and rheometry in small amplitude oscillatory shear. The distribution state of the clay between the two phases (PP and EPDM) was found to be dependent on the viscosity ratio of PP to EPDM. In the nanocomposites prepared based on low viscosity PP (LVP) and EPDM, the clay was mostly dispersed into the PP phase and the size of the dispersed rubber particles decreased in comparison with unfilled but otherwise similar blends. However, the dispersed elastomer droplet size in the high viscosity PP (HVP) blends containing 40 and 60% EPDM increased with the introduction of the clay. For TPE nanocomposites, the dependence of the storage modulus (G′) on angular frequency (ω) followed a clear nonterminal behavior. The increase in the storage modulus and the decrease in the terminal zone slope of the elastic modulus curve were found to be larger in the LVP nanocomposite in comparison with the HVP sample. The yield stress of nanoclay‐filled blends prepared with LVP increased more than that of HVP samples. The tensile modulus improved for all nanocomposites but a higher percentage of increase was observed in the case of LVP samples. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Effect of bifunctional modifiers of the clay on the morphology of novolac cured epoxy resin/clay nanocomposites
Authors: Tsai Tsung‐Yen , Lu Shau‐Tai , Li Chih‐Hung , Huang Chin‐Jei , Liu Jia‐Xiang , Chen Li‐Chun 
Published: April 2008

AbstractMontmorillonite type clay, (PK‐802) is modified by the bifunctional modifiers (2‐phenylimidazole/benzalkonium chloride, PI/BEN or 2‐methylimidazole/benzalkonium chloride, MI/BEN) with different ratio, which contain a curing agent, BEN, and the promoters/accelerator (PI and MI). These two modifying agents are simultaneously intercalated into the gallery space of pure PK‐802. The novolac cured epoxy nanocomposites are prepared with this modified clay by crosslinking polymerization reaction. Wide‐angle X‐ray diffraction is used to measure the resulting d‐spacing of modified PK‐802 and the nanocomposites. Thermo‐gravimetric analysis is used to characterize the thermal properties of the nanocomposites. The morphology of the nanocomposites is investigated using transmission electron microscopy techniques. Well dispersion of clay into the novolac cured epoxy‐clay nanocomposites resulted when simultaneously both the modifying agents with 5:5 mole ratios are used to modify the clay instead of using single modified agent. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers