bluuebunny/crossref_metadata_2025 huggingface dataset:
Encoding of anisotropic diffusion with tetrahedral gradients: A general mathematical diffusion formalism and experimental results
Authors: Conturo Thomas E. , McKinstry Robert C. , Akbudak Erbil , Robinson Bruce H.
Published: February 2011

A diffusion imaging method with a tetrahedral sampling pattern has been developed for high‐sensitivity diffusion analysis. The tetrahedral gradient pattern consists of four different combinations of x, y, and z gradients applied simultaneously at full strength to uniformly measure diffusion in four different directions. Signal‐to‐noise can be increased by up to a factor of about three using this approach, compared with diffusion measurements made using separately applied x, y, and z gradients. A mathematical formalism is presented describing six fundamental parameters: the directionally averaged diffusion coefficient D and diffusion element anisotropies η and ε which are rotationally invariant, and diffusion ellipsoid orientation angles θ, ϕ, and Ψ which are rotationally variant. These six parameters contain all the information in the symmetric diffusion tensor D. Principal diffusion coefficients, reduced anisotropies, and other rotational invariants are further defined. It is shown that measurement of off‐diagonal tensor elements is essential to assess anisotropy and orientation, and that the only parameter which can be measured with the orthogonal method is D. In cases of axial diffusion symmetry (e.g., fibers), the four tetrahedral diffusion measurements efficiently enable determination of D, η, θ, and ϕ which contain all the diffusion information. From these four parameters, the diffusion parallel and perpendicular to the symmetry axis (D1 and D1) and the axial anisotropy A can be determined. In more general cases, the six fundamental parameters can be determined with two additional diffusion measurements. Tetrahedral diffusion sequences were implemented on a clinical MR system. A muscle phantom demonstrates orientation independence of D, D1, D1, and A for large changes in orientation angles. Sample background gradients and diffusion gradient imbalances were directly measured and found to be insignificant in most cases.
Multiple breathhold 3D time‐of‐flight MR angiography of the renal arteries
Authors: Wilman Alan H. , Riederer Stephen J. , Grimm Roger C. , Rossman Phillip J. , Wang Yi , King Bernard F. , Ehman Richard L.
Published: February 2011

A technique is described for angiographic imaging of the renal arteries with acquisition performed over several periods of suspended respiration. The 3D Fourier transform (FT) gradient‐echo angiographic sequence uses magnetization preparation and appropriately chosen delay times for background nulling and time‐of‐flight enhancement of the vasculature. The sequence was applied to 10 volunteers, each of whom was imaged in three ways: (i) over a series of breathholds in which feedback was provided to enable reproducible breath‐holding; (ii) over a series of breathholds with no feedback; and (iii) over continuous respiration. Results were evaluated by measuring the transverse extent of the well‐delineated renal vasculature and by noting the distal extent of the vasculature branching (main, segmental, and interlobar branches). The transverse extent of renal vasculature visible with breathhold feedback, breathholding, and free breathing was 6.1 ± 0.9 cm, 5.0 ±1.8 cm, and 4.0 ±1.4 cm, respectively (mean ± SD). Breathhold feedback enabled visualization of segmental renal arteries bilaterally in all 10 volunteers.
Brain alcohol detectability increase with repeated administration in humans: A proton spectroscopy study
Authors: Kaufman Marc J. , Chiu Tak‐Ming , Mendelson Jack H. , Woods Bryan T. , Teoh Siew K. , Erös‐Sarnyai Monika , Mercer Greg , Mello Nancy K.
Published: February 2011

Proton MRS was used to detect brain alcohol after repeated alcohol exposure in human subjects. MRS detectability measurements were made after administration of an alcoholic drink (0.6 g/kg alcohol) and after an identical drink administered 6 h later. Between‐drink differences in the methyl proton triplet resonance of ethyl alcohol were assessed at statistically equivalent and near‐peak blood alcohol concentrations (reflecting brain alcohol concentrations) and statistically equivalent internal standard N‐acetyl resonance areas after Drinks 1 and 2, respectively. Brain alcohol detectability was not altered in TE 30‐ms spectra but was increased in all five subjects after Drink 2 by an average of 70% in TE 270‐ms spectra (P < 0.01). This was accompanied by significant between‐drink differences in subjective ratings of alcohol's effects, suggestive of induction of acute alcohol tolerance. These findings suggest increased brain alcohol detectability in TE 270‐ms spectra after repeated alcohol exposure that may reflect acute alcohol tolerance.
Application of 31P NMR spectroscopy to monitor chemotherapy‐associated changes of serum phospholipids in patients with malignant lymphomas
Authors: Kuliszkiewicz‐Janus Małgorzata , Baczyński Stanisław
Published: February 2011

31P spectra were obtained from 22 healthy volunteers and 35 patients with malignant lymphomas. Sera from patients were collected at the time of diagnosis and at several time‐points during therapy. Long‐term follow‐up studies showed a good correlation between the 31P NMR spectra of sera and the clinically evident response of the disease to the chemotherapy. During therapy leading to remission resonance from phospholipids increased progressively resulting in spectra similar to those seen in normal sera. By contrast, in patients who did not respond to therapy the intensities of the phospholipid peaks remained relatively low or became progressively reduced as the disease progressed. To understand the source of the spectral differences, we also examined the concentrations of high‐density lipoprotein, low‐density lipoprotein, cholesterol, and triglycerides. In individuals responding to the treatment, both high‐density lipoprotein and cholesterol increased to the point where they were statistically equivalent to those from healthy volunteers.
Fast proton spectroscopic imaging employing k‐space weighting achieved by variable repetition times
Authors: Kühn Bernd , Dreher Wolfgang , Norris David G. , Leibfritz Dieter
Published: February 2011

A k‐space weighted spectroscopic imaging (SI) method is presented that allows a reduction in the total data acquisition time by up to 55% compared with standard SI. The k‐space weighting is achieved by varying the repetition time, thus realizing an inherent apodization that corresponds to a circularly symmetric generalized Hamming filter. The flip angle is varied with the repetition time to enhance the signal‐to‐noise ratio. These techniques were employed using a short echo time of 10 ms. In vivo measurements on healthy rat brain at 4.7 T were conducted, obtaining two‐dimensional spectroscopic imaging data from a 25 × 25 circularly reduced k‐space area in as little as 5 min. The signal‐to‐noise ratio is sufficiently high to detect J‐coupled resonances such as myo‐inositol or glutamate/glutamine, demonstrating the ability to combine short acquisition times with comprehensive metabolic information. The T1 dependency of the apodization and the corresponding point spread function was evaluated by computer simulations. The achievable signal‐to‐noise ratio per unit time was compared with standard SI giving a parameter‐dependent advantage of approximately 20% of the standard SI method.
Simultaneous localized 1H STEAM/31P ISIS spectroscopy in Vivo
Authors: van Sluis Robert , Yongbi Ngong M. , Payne Geoffrey S. , Leach Martin O.
Published: February 2011

A sequence for simultaneous acquisition of 1H STEAM and 31P ISIS spectra is described, and 1H and 31P spectra obtained simultaneously from the same volume of interest in both a phantom and a volunteer are presented. The STEAM and ISIS parts of the sequence use a common gradient scheme that is also used during the localized shimming process, partially compensating for eddy current effects. It is demonstrated that this method of simultaneous multinuclear spectroscopy does not compromise the localization performance of the sequence.
Fourier tracking of myocardial motion using cine‐PC data
Authors: Zhu Yudong , Drangova Maria , Pelc Norbert J.
Published: February 2011

A closed‐form integration method is derived and analyzed for computing motion trajectories from velocity field data, particularly as measured by phase contrast (PC) cine MR imaging. By modeling periodic motion as composed of Fourier harmonics and integrating the material velocity of the tracked point in the frequency domain, this method gives an unbiased trajectory estimate in the presence of white measurement noise and eddy current effects. When applied to cine PC data, the method can incorporate compensation for the frequency response of the cine interpolation, offering a further improvement on the tracking accuracy. In simulation and phantom studies, the estimated trajectories were in excellent agreement with the true trajectories. Encouraging results have also been obtained on data from volunteers.
31P NMR measurements of the effects of unsaturated fatty acids on cellular phospholipid metabolism
Authors: Gillham Helen , Brindle Kevin M.
Published: February 2011

31P NMR measurements on extracts prepared from a variety of cultured mammalian cell lines and primary rat hepatocytes have shown changes in the levels of several phospholipid metabolites after incubation of cells with unsaturated fatty acids. These data suggest a possible link between the accumulation of neutral lipid and the changes in phospholipid metabolite concentrations that have been observed in some tumor cells and other rapidly growing tissues such as the regenerating liver and mitogen‐stimulated lymphocytes.
1H magnetic cross‐relaxation between multiple solvent components and rotationally immobilized protein
Authors: Hinton Denise P. , Bryant Robert G.
Published: February 2011

Magnetic cross‐relaxation spectra or Z‐spectra are presented for water, acetone, methanol, dimethylsulfoxide, and acetonitrile in cross‐linked bovine serum albumin gels. Each solvent studied, reports the same Z‐spectrum linewidth and shape for the solid component that follows from solutions of the coupled relaxation equations. The Z‐spectra demonstrate competition among solvents for specific protein binding sites. The rate of magnetization transfer in the rotationally immobilized protein environment is approximated by 1/T2 for the solid component, which is shown to account for the observed magnetization transfer rates in the systems studied. The temperature dependence of the Z‐spectra are different for water compared with the organic solvents. The cross‐relaxation efficiency in the organic solvents decreases with increasing temperature because molecules bind less well at high temperature. For water, the hydrogen exchange path becomes increasingly important relative to the whole molecule path with increasing temperature, which improves the net cross‐relaxation efficiency.
Coherence transfer by isotropic mixing in carr‐purcell‐meiboom‐gill imaging: Implications for the bright fat phenomenon in fast spin‐echo imaging
Authors: Williamson Daniel S. , Mulkern Robert V. , Jakab Peter D. , Jolesz Ferenc A.
Published: February 2011

It is well known that when compared to conventional spin‐echo (CSE) imaging for equivalent effective echo times, fast spin‐echo (FSE) imaging experiments yield higher signal intensities for coupled spin systems, such as that for lipid. One hypothesis put forth for this phenomenon is the removal of scalar coupling‐based echo amplitude modulation by the FSE ψ pulse train. This would result in the maintenance of signal intensity in the late echoes, with an overall increase in image signal when the multiecho train data is combined to form the image data. It will be shown that in images and spectra obtained from the final echo of a Carr‐Purcell‐Meiboom‐Gill (CPMG) ψ pulse train, an increase in signal in coupled spin systems occurs, when compared to conventional single‐echo images and spectra at identical echo times. One‐ and two‐dimensional spectroscopy experiments confirm that it is the generation of an isotropic mixing Hamiltonian by the ψ pulse train in FSE that is responsible for the increased signal in images of a simple AX system and of corn oil, a model for human fat. This relative increase in signal is due to the maintenance of in‐phase magnetization in the coupled spin systems by this Hamiltonian. In CSE, the weak coupling Hamiltonian allows development of antiphase coherences which, in the presence of the line broadening due to the imaging gradients, result in signal loss.
Quantitative magnetic resonance imaging of perfusion using magnetic labeling of water proton spins within the detection slice
Authors: Schwarzbauer Christian , Morrissey Sean P. , Haase Axel
Published: February 2011

A technique for noninvasive quantitative magnetic resonance imaging of perfusion is presented. It relies on using endogenous water as a freely diffusible tracer. Tissue water proton spins are magnetically labeled by slice‐selective inversion, and longitudinal relaxation within the slice is detected using a fast gradient echo magnetic resonance imaging technique. Due to blood flow, nonexcited spins are washed into the slice resulting in an acceleration of the longitudinal relaxation process. Incorporating this phenomenon into the Bloch equation yields an expression that allows quantification of perfusion on the basis of a slice‐selective and a nonselective inversion recovery experiment. Based on this technique, quantitative parameter maps of the regional cerebral blood flow (rCBF) were obtained from eight rats. Evaluation of regions of interest within the cerebral hemispheres yielded an average rCBF value of 104 ± 21 ml/min/100 g, which increased to 219 ± 30 ml/min/100 g during hypercapnia. The measured rCBF values are in good agreement with previously reported literature values.
Rapid repetition of the “burst” sequence: The role of diffusion and consequences for imaging
Authors: Doran Simon J. , Jakob Peter , Décorps Michel
Published: February 2011

When the Burst pulse sequence (Hennig ef al. MAGMA 1, 39–48 (1993)) is applied with elementary pulses of finite flip angle, a non‐uniform longitudinal magnetization is created, in the form of a series of fine bands of saturated spins. Both during and after the pulse train, the molecules contained within these bands diffuse. In this paper a full description is given of the evolution of the non‐uniform longitudinal magnetization subsequent to the pulse train and the theory is verified experimentally. The value of the diffusion coefficient influences strongly the signal obtained when the Burst sequence is repeated rapidly. The consequences of this for imaging are discussed and, in particular, for the so‐called “frequency‐shifted” Burst technique.
Implementation of a fast gradient‐echo SVD encoding technique for dynamic imaging
Authors: Panych Lawrence P. , Oesterle Claudia , Zientara Gary P. , Hennig Jürgen
Published: February 2011

In the paper, the results of a fast gradient‐echo implementation of the singular value decomposition (SVD) encoding technique for dynamic imaging are presented. The method used is an adaptation with several critical modifications of a keyhole‐type approach previously proposed but not implemented. The method was tested by imaging the events following injection of a contrast agent into a phantom, producing a series of dynamic image updates. It is demonstrated that, for this type of application, the SVD encoding technique adequately follows dynamic changes with even a small number of encodes. The result is comared qualitatively to that obtained by standard Fourier‐based keyhole imaging and is shown to provide improved spatial resolution of dynamic events when updating with the same number of encodes.
Phase‐Modulated binomial RF pulses for fast spectrally‐selective musculoskeletal imaging
Authors: Thomasson David , Purdy David , Finn J. Paul
Published: February 2011

Two fat‐suppressed three‐dimensional gradient echo pulse sequences, FLASH and DESS (Double Echo in Steady‐State), that have significantly reduced scan time compared with conventional chemical shift fat‐suppression sequences are presented. This fat‐suppression technique is based on selectively exciting water spins using a time‐optimized binomial RF pulse pair at the water resonance frequency with a null in the excitation profile at the fat frequency. To minimize the total pulse length, the delay between the binomial components of the RF pulse is decreased from a standard jump‐return implementation. To maintain the proper null frequency, the phase of the second RF pulse is shifted such that it returns the fat resonance back to its initial z position while further tipping the water spins. Nonselective phase‐modulated RF pulse pairs can be implemented in 1.20 ms at 1.0 T, significantly reducing the minimum TR.
Calculation of the magnetization distribution for fluid flow in curved vessels
Authors: Jou Liang‐Der , van Tyen Rem , Berger Stanley A. , Saloner David
Published: February 2011

The signal Intensity in magnetic resonance angiography (MRA) images reflects both morphological and flow‐related features of vascular anatomy. A thorough understanding of MRA, therefore, demands a careful analysis of flow‐related effects. Computational fluid dynamics (CFD) methods are very powerful in determining flow patterns in 3D tortuous vessels for both steady and unsteady flow. Previous simulations of MRA images calculated the magnetization of flowing blood by tracking particles as they moved along flow streamlines that had been determined by a CFD calculation. This manuscript describes MRA simulations that use CFD calculations to determine magnetization variation at a fixed point and, therefore, do not require streamline tracking to calculate the distribution of magnetization in flowing fluids. This method inherently accounts for uniform particle density, avoids problems associated with tracking particles close to the wall, and is well‐suited to modeling pulsatile flow.
The effect of magnetization transfer in meniscal fibrocartilage
Authors: Adler Ronald S. , Swanson Scott D. , Doi Kei , Craig Joseph G. , Aisen Alex M.
Published: February 2011

Magnetic resonance imaging of the knee was performed in 28 patients (ages 15–72 years), using a 1.5‐T unit. Volume gradient echo (3D GRASS) acquisition with and without presaturation off‐resonance RF pulse was used to evaluate magnetization transfer (MT) effects, determined by placing regions of Interest on muscle, fat, hyaline, and fibrocartilage; the percent change in signal intensity was calculated and compared using a paired two‐sample t test. An in vitro study of the normal meniscus from a cadaver containing a scalpel cut extending to an articular surface was performed to observe the relative improvement in contrast in the presence of a small meniscal defect. MR imaging of the specimen was performed using an Omega CSI 2.0–T system (General Electric Medical Systems, Fremont, CA). Analysis of clinical images resulted in signal loss, compared to that of the identically timed and tuned non‐MT images of 47 ± 5, 8 ± 5, 49 ± 5, and 57 ± 7% for muscle, fat, articular cartilage and fibrocartilage, respectively. Application of MT improved the depiction of the artificially introduced meniscal defect. Meniscal fibrocartilage demonstrates significant MT effect after application of off‐resonance RF presaturation, which may improve visualization of meniscal defects.
Temporal resolution improvement in dynamic imaging
Authors: Fredrickson Jill O. , Pelc Norbert J.
Published: February 2011

In some dynamic imaging applications, only a fraction, 1/n, of the field of view (FOV) may show considerable change during the motion cycle. A method is presented that improves the temporal resolution for a dynamic region by a factor, n, while maintaining spatial resolution at a cost of √n in signal‐to‐noise ratio (SNR). Temporal resolution is improved, or alternatively, total imaging time is reduced by reducing the number of phase encodes acquired for each temporal frame by 1/n. To eliminate aliasing, a representation of the signal from the static outer portion of the FOV is constructed using all the raw data. The k‐space data derived from this representation is subtracted from the original data sets, and the differences correspond to the dynamic portion of the FOV. Improved resolution results are presented in phantom studies, and in vivo phase contrast quantitative flow imaging.
1H‐MRS can detect aberrant glycosylation in tumour cells: a study of the HeLa cell line
Authors: Palma Alessandra , Grande Sveva , Rosi Antonella , Luciani Anna Maria , Guidoni Laura , Viti Vincenza
Published: February 2011

Glycosylation is the most abundant and diverse form of post‐translational modification of proteins. Two types of glycans exist in glycoproteins: N‐glycans and O‐glycans often coexisting in the same protein. O‐glycosylation is frequently found on secreted or membrane‐bound mucins whose overexpression and structure alterations are associated with many types of cancer. Mucins have several cancer‐associated structures, including high levels of Lewis antigens characterized by the presence of terminal fucose. The present study deals with the identification of MR signals from N‐acetylgalactosamine and from fucose in HeLa cells by detecting a low‐field signal in one‐dimensional (1D) spectra assigned to the NH of N‐acetylgalactosamine and some cross peaks assigned to fucose in two‐dimensional (2D) spectra. The increase of Golgi pH by treatment with ammonium chloride allowed the N‐acetylgalactosamine signal assignment to be confirmed. Behaviour of MR peak during cell growth and comparison with studies from literature taken together made it possible to have more insight into the relationship between aberrantly processed mucin and the presence of non‐processed N‐acetylgalactosamine residues in HeLa cells. Fucose signals, tentatively ascribed to residues bound to galactose and to N‐acetylglucosamine, are visible in both intact cell and perchloric acid spectra. Signals assigned to fucose bound to galactose are more evident in ammonium chloride‐treated cells where structural changes of mucin‐related Lewis antigens are expected as a result of the higher Golgi pH. A common origin for the N‐acetylgalactosamine and fucose resonances attributing them to aberrantly processed mucin can be inferred from the present results. Copyright © 2011 John Wiley & Sons, Ltd.
The Journal of Pathology's approach to publication ethics and misconduct
Authors: Hall Peter A , Wixon Jo , Poulsom Richard
Published: February 2011

This Editorial highlights recent changes at The Journal of Pathology intended to improve our ability to detect, and we hope deter, instances of ethical misconduct among submissions made to the Journal, such as cases of guest authorship and plagiarism. We also discuss our experience to date and describe our policies for dealing with such cases. These changes are all encapsulated in our full online Author Guidelines. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Hypoxia‐inducible factor‐1 signalling promotes goblet cell hyperplasia in airway epithelium
Authors: Polosukhin Vasiliy V , Cates Justin M , Lawson William E , Milstone Aaron P , Matafonov Anton G , Massion Pierre P , Lee Jae Woo , Randell Scott H , Blackwell Timothy S
Published: February 2011

Goblet cell hyperplasia is a common feature of chronic obstructive pulmonary disease (COPD) airways, but the mechanisms that underlie this epithelial remodelling in COPD are not understood. Based on our previous finding of hypoxia‐inducible factor‐1α (HIF‐1α) nuclear localization in large airways from patients with COPD, we investigated whether hypoxia‐inducible signalling could influence the development of goblet cell hyperplasia. We evaluated large airway samples obtained from 18 lifelong non‐smokers and 13 former smokers without COPD, and 45 former smokers with COPD. In these specimens, HIF‐1α nuclear staining occurred almost exclusively in COPD patients in areas of airway remodelling. In COPD patients, 93.2 ± 3.9% (range 65–100%) of goblet cells were HIF‐1α positive in areas of goblet cell hyperplasia, whereas nuclear HIF‐1α was not detected in individuals without COPD or in normal‐appearing pseudostratified epithelium from COPD patients. To determine the direct effects of hypoxia‐inducible signalling on epithelial cell differentiation in vitro, human bronchial epithelial cells (HBECs) were grown in air–liquid interface cultures under hypoxia (1% O2) or following treatment with a selective HIF‐1α stabilizer, (2R)‐[(4‐biphenylylsulphonyl)amino]‐N‐hydroxy‐3‐phenyl‐propionamide (BiPS). HBECs grown in hypoxia or with BiPS treatment were characterized by HIF‐1α activation, carbonic anhydrase IX expression, mucus‐producing cell hyperplasia and increased expression of MUC5AC. Analysis of signal transduction pathways in cells with HIF‐1α activation showed increased ERK1/2 phosphorylation without activation of epidermal growth factor receptor, Ras, PI3K‐Akt or STAT6. These data indicate an important effect of hypoxia‐inducible signalling on airway epithelial cell differentiation and identify a new potential target to limit mucus production in COPD. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Revisiting cancer immunoediting by understanding cancer immune complexity
Authors: Manjili Masoud H
Published: February 2011

Since 1909, the cancer immunosurveillance concept has undergone four distinct eras. These include a general acceptance during 1957–1974, an abandonment during 1974–1996, resurrection during 1996–2001 in the form of an elegant theory of tumour immunoediting proposed by Robert Schreiber, and a retreat since 2006. Recently, in the Journal of Pathology, Ciampricotti et al reported an elegant experimental model designed by establishing RAG2−/−/MMTV‐NeuT mice. Using this, they demonstrated that the development and metastasis of HER‐2/neu‐positive spontaneous mammary carcinoma were not altered by the presence or absence of the adaptive immune system. Their fascinating results are a call to revisit controversial reports as to an effective role of the adaptive immune system in tumour inhibition versus tumour promotion or tolerance in the development of spontaneous carcinomas. Ciampricotti and colleagues present a strong case for revising our ideas of cancer immunoediting and appreciating the complexity of the interaction between cancer and the immune system. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Invited commentary for Ciampricotti M et al. Development of metastatic HER2+ breast cancer is independent of the adaptive immune system. Journal of Pathology. 2011; 224: 56–66. http://dx.doi.org/10.1002/path.2837
Talin‐1 overexpression defines high risk for aggressive oral squamous cell carcinoma and promotes cancer metastasis
Authors: Lai Ming‐Tsung , Hua Chun‐Hung , Tsai Ming‐Hsui , Wan Lei , Lin Ying‐Ju , Chen Chih‐Mei , Chiu I‐Wen , Chan Carmen , Tsai Fuu‐Jen , Jinn‐Chyuan Sheu Jim
Published: February 2011

Oral squamous cell carcinoma (OSCC) is highly invasive and is associated with frequent tumour recurrences and lymph node metastases. Identification of genes involved in the aggressiveness of OSCC may provide new targets for clinical intervention. A genome‐wide study based on the Sty1 250K SNP array indicated the involvement of the Talin‐1 (TLN1) gene in the 9p13.3 amplicon, which was further validated by dual colour fluorescence in situ hybridization (FISH). Comparative analyses revealed that TLN1 was the most highly expressed integrin‐cytoskeleton cross‐linker that can trigger integrin activation. IHC analyses and mouse study also revealed an association between TLN1 overexpression and advanced OSCC with invasion to adjacent tissues. Survival analyses indicated a significant association between TLN1 genetic gain/overexpression and a reduced overall survival in patients. Functional knockdown by a dominant negative TLN1 fragment reduced cell growth and invasiveness in TLN1‐overexpressing cells via inactivation of downstream oncogenic signalling. The present study suggests an important role for TLN1 in oral cancer development. TLN1 overexpression could serve as a diagnostic marker for aggressive phenotypes and a potential target for treating OSCC. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Vitamin D status in paediatric patients with cancer
Authors: Sinha Akash , Avery Peter , Turner Steve , Bailey Simon , Cheetham Tim
Published: February 2011

Background

Children with malignant disease are at increased risk of bone disorders and cardiovascular disease. Vitamin D status may influence this risk and so we assessed vitamin D levels in children with malignant disease undergoing active treatment or surveillance post‐therapy.

Procedure

This was an outpatient‐based cross‐sectional study of 61 children with a history of malignancy (median age 11.1 years; range 1.5–24.4 years) and 60 control subjects (median age 8.4 years; range 0.2–18.0 years) attending hospital for the management of non‐malignant disorders. Serum vitamin D (25‐OH‐D), parathormone levels and bone biochemistry were determined. Vitamin D status and its relationship to age, sex, ethnicity, time of sampling and presence of malignant disease was determined.

Results

Vitamin D status was suboptimal in 62% of cases (25‐OH‐D < 50 nmol/L [20 ng/ml]). Vitamin D deficiency (25‐OH‐D < 25 nmol/L [10 ng/ml]) was more common in children with malignant disease than controls (21.3% vs. 3.3%; P = 0.013). Month of sampling (P < 0.001), ethnicity (P < 0.001), older age (P = 0.011), and history of malignancy (P = 0.012) were associated with a poorer vitamin D status.

Conclusions

Vitamin D levels [25‐OH‐D] are lower in survivors of childhood cancer in comparison to control children with the majority either insufficient or deficient. Assessment and adequate replacement of vitamin D status may be of particular value in this group of children. Pediatr Blood Cancer 2011; 57: 594–598. © 2011 Wiley‐Liss, Inc.
AML1/RUNX1 gene point mutations in childhood myeloid malignancies
Authors: Migas Alexandr , Savva Natallia , Mishkova Olga , Aleinikova Olga V.
Published: February 2011

Background

Currently, it is widely accepted that one of the crucial players in adult leukemic transformation is the RUNX1 gene. However, there is little data available regarding whether mutations in this gene also contribute to pediatric leukemia, especially in childhood myeloid malignancies. Therefore we made a decision to screen patients with pediatric myeloid neoplasias for the presence of RUNX1 mutations in their samples.

Procedures

Patients (n = 238) with diagnoses of de novo acute myeloid leukemia (AML) (n = 198), de novo myelodisplastic syndrome (MDS) (n = 16), therapy‐related AML (n = 9), juvenile myelomonocytic leukemia (JMML) (n = 15) were included in this study. All patients were Belarusians between the ages of 0 and 18 years.

Results

The frequency of RUNX1 point mutations in the total group of patients with de novo AML was 3% and de novo MDS was 15%. Cooperation of point mutations in the RUNX1 and NRAS genes, and the cytogenetic abnormality, ‐7/7q‐, was demonstrated in children with therapy‐related AML. RUNX1 point mutations predominate in those de novo AML and MDS patients with a normal karyotype in leukemic cells. Frequency of RUNX1 point mutations was about 4% in a group of children with de novo AML aged 0–14 years diagnosed during the period of 1998–2009.

Conclusion

During the course of this investigation, valuable data were obtained concerning RUNX1 gene mutation frequencies in different clinical, morphological, and cytogenetic groups of patients with myeloid malignancies, and its cooperation with other molecular aberrations. Pediatr Blood Cancer 2011; 57: 583–587. © 2011 Wiley‐Liss, Inc.
Green composites from wheat protein isolate and Hildegardia Populifolia natural fabric
Authors: Jagadeesh Dani , Jeevan Pradsad Reddy D. , Varada Rajulu A. , Li R.
Published: February 2011

Completely biodegradable composites were prepared using modified wheat protein isolate (WPI) as matrix and the uniaxial natural fabric Hildegardia Populifolia as reinforcement. The WPI was cross‐linked with glutaraldehyde in the presence of glycerol plasticizer. These polymer composites were subsequently subjected to evaluation for their mechanical, morphological (SEM), thermal (TGA/DMA) properties, and biodegradation behavior. The mechanical properties such as tensile strength and flexural strength of the composite increased with increase in fabric loading up to 10% and decreased therefore. Further, the alkali treatment of the fabric and use of a coupling agent enhanced the mechanical properties. The scanning electron micrographs of the fractured surface of the composites indicated facilitation of better bonding between the matrix and reinforcement by the coupling agent. In case of thermal behavior, results indicated that the presence of fabric affected the thermal stability of polymer matrix. Biodegradability of the composites was also been studied by soil burial method, and the composites were found to degrade up to 95% in 35 days. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Mechanical properties of polyamide 6 reinforced microfibrilar composites
Authors: Dencheva Nadya V. , Oliveira Maria J. , Pouzada Antonio S. , Kearns Mark P. , Denchev Zlatan Z.
Published: February 2011

The mechanical behavior of microfibrilar composites (MFC), consisting of a matrix of high‐density polyethylene (HDPE) and reinforcement of polyamide 6 (PA6) fibrils, with and without compatibilization, was studied. The composites were produced by conventional processing techniques with various shape and arrangement of the PA6 reinforcing entities: long, unidirectional, or crossed bundles of fibrils (UDP and CPC, respectively), middle‐length, randomly oriented bristles (MRB), or non‐oriented micrometric PA6 spheres (NOM). The tensile, flexural, and impact properties of the MFC materials (UDP, CPC, and MRB) were determined as a function of the PA6 reinforcement shape, alignment and content, and compared with those of NOM, the non‐fibrous composite. It was concluded that the in‐situ MFC materials based on HDPE/PA6 blends display improvements in the mechanical behavior when compared with the neat HDPE matrix, e.g., up to 33% for the Young modulus, up to 119% for the ultimate tensile strength, and up to 80% for the flexural stiffness. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Effect of filler‐polymer interactions on the crystalline morphology of PEO‐based solid polymer electrolytes by Y2O3 nano‐fillers
Authors: Liang Guijie , Xu Jie , Xu Weilin , Shen Xiaolin , Zhang Hui , Yao Mu
Published: February 2011

A novel lithium solid polymer electrolyte (SPE) based on polyethylene oxide (PEO) matrix and yttrium oxide (Y2O3) as nano‐filler was prepared by solution casting technique. The Lewis acid‐based filler‐polymer coordination interactions between the surface of Y2O3 and the ether oxygen of PEO were proved by FTIR, which induced an obvious modification of crystalline morphology of the PEO‐based SPEs. Polarized optical microscope (POM) analysis shows that the induced nucleation and steric hindrance effects of Y2O3 nano‐filler result in the increased amount as well as decreased size of spherulites in the PEO matrix, respectively. Atomic force microscope (AFM) images indicate the surface morphology of PEO gets rougher as Y2O3 content increases. X‐ray diffractomer (XRD) and differential scanning calorimetry (DSC) results demonstrate the crystallinity of SPEs decreases from 51.1% to 32.5% with the Y2O3 weight ratio [m(Y2O3)/m(PEO+LiI)] increasing from 0 to 0.15. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Poly(butylene succinate)‐based biocomposites filled with polysaccharide nanocrystals: Structure and properties
Authors: Lin Ning , Yu Jiahui , Chang Peter R. , Li Junli , Huang Jin
Published: February 2011

In this work, two polysaccharide nanocrystals‐rod‐like cellulose whisker (CW) and platelet‐like starch nanocrystal (SN) were individually incorporated into an aliphatic thermoplastic polyester to produce biodegradable poly(butylene succinate) (PBS)/nanocrystals biocomposites. At loading levels of 2 wt% CW or 5 wt% SN the PBS‐based nanocomposites showed simultaneous enhancement of strength and elongation compared to the neat PBS. This was primarily attributed to the uniform dispersion of nanofillers and strong interfacial adhesion between filler and matrix. Nucleation of the nanocrystals, formation of a percolating network, and interaction between filler and matrix collectively contributed to the improvement of crystallinity and thermal properties of the composites. This high performance, fully biodegradable, eco‐friendly nanocomposite will expand the utilization of polysaccharide nanocrystals from renewable bioresources and the practical application of PBS. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
High molecular weight poly (L‐lactic acid) clay nanocomposites via solid‐state polymerization
Authors: Katiyar Vimal , Nanavati Hemant
Published: February 2011

We propose here, a novel technique to synthesize high molecular weight (MW) poly (L‐lactic acid)‐clay nanocomposite (PLACN), via solid state polymerization (SSP). We synthesize prepolymer of PLACN (pre‐PLACN) from both,L‐lactic acid andL‐lactide, as starting materials. Synthesis of pre‐PLACN fromL‐lactic acid is carried out viain situmelt polycondensation (MP) ofL‐lactic acid oligomer, followed by SSP, to achieve high MW PLACN (Mw∼ 138,000 Da). In case ofL‐lactide as the starting material, we prepareL‐lactide–clay intercalated mixture which yields moderate MW pre‐PLACN during subsequent ring opening polymerization (ROP). Interestingly, ROP is performed by using hydroxyl functionalized ternary catalyst system (L‐lactide–Sn(II) octoate–oligo (L‐lactic acid) complex), which provides the terminal hydroxyl end‐groups, required for step‐growth SSP. Pre‐PLACN MW is now increased toMw∼ 127,000 Da, by the subsequent SSP process.1H NMR analyses confirm that these end‐groups, are indeed consumed during SSP. During SSP, the PLACN also achieves up to 90% crystallinity, which may be due to the synchronization of the slow step‐growth SSP of poly(L‐lactic acid) (PLA) with the crystallization kinetics. Optical purity of PLACNs is similar to that of neat PLA, whereas the thermal stability of PLACNs is significantly superior. As evidenced by wide‐angle X‐ray scattering/small‐angle X‐ray scattering analyses and in line with the literature, both, intercalated and exfoliated PLACN morphologies, have been synthesized, by suitable selection of clays. We also verify the correlation between the PLA semicrystalline morphology and the PLACN morphology, which is consistent with those of PLACN synthesized by other techniques. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Curing kinetics of NBR filled with coconut flour
Authors: Herrera R. , Ichazo M.N. , Albano C. , Hernández M. , González J.
Published: February 2011

The purpose of this investigation was to evaluate the effect of the incorporation of 20 phr of coconut woodflour of different particle sizes on the vulcanization kinetics of Nitrile Rubber (NBR) by means of rheometry and differential scanning calorimetry. The vulcanization kinetics results suggest that there might exist agglomerates of small particles (< 300 μm), which interfere with the curing reaction of the NBR. The reaction orders corresponding to the autocatalytic reaction show an increase with the extent of the reaction and with the rise on temperature. A good correlation of the vulcanization kinetics was obtained employing the generic model that involves constants associated to the reaction mechanisms, which in turn depend on the components present in the initial mix and on the autocatalytic reaction. The Osawa and Kissinger equations reproduce in a similar way the vulcanization kinetics of the compounds. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Dielectric, FTIR spectroscopic and atomic force microscopic studies on polypyrrole‐poly(acrylonitrile‐co‐vinyl acetate) composites
Authors: Cetiner Suat , Kalaoglu Fatma , Karakas Hale , Sarac A. Sezai
Published: February 2011

In this study, Poly(acrylonitrile‐co‐vinyl acetate) [P(AN‐co‐VAc)] composite films were fabricated by chemical polymerization of pyrrole (Py) with cerium(IV) (Ce(IV)) on P(AN‐co‐VAc) matrix. The effect of amount of Py and temperature on the composite film properties was studied in a frequency range starting from 0.05 Hz to 10 MHz and in a temperature range from 0 to 250°C. The electric modulus provides a good description of the dielectric relaxation of the conducting polymer composites. The atomic force microscopy images of the polypyrrole (PPy)‐P(AN‐co‐VAc) composites show the polymerization of Py on P(AN‐co‐VAc) matrix producing different sized grainy orientations resulting in higher conductivity values that increase with average grain size. The real [(ε′) or ε′(ω)] and imaginary [(ε″) or ε″(ω)] parts of the permittivity of PPy‐P(AN‐co‐VAc) composite were comparatively higher than PPy‐Polyacrylonitrile (PAN) and P(AN‐co‐VAc). It was also seen that the conductivity of PPy‐P(AN‐co‐VAc) composite was considerably higher than PPy‐PAN and P(AN‐co‐VAc) itself. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Mechanical properties of nanosilica/polypropylene composites under dynamic compression loading
Authors: Omar Mohd Firdaus , Akil Hazizan Md , Ahmad Zainal Arifin
Published: February 2011

This article presents results on the dynamic mechanical properties of PP‐SiO2 nanocomposites, with nanosilica contents of 1, 3, and 5% by weight, at various strain rates using a Split Hopkinson Pressure Bar (SHPB) apparatus. The specimens were prepared using a hot compression technique. The dynamic mechanical characteristics, of PP‐SiO2 nanocomposites, are illustrated in terms of stress–strain curves, up to nearly 1100 s−1 of strain rates. From the results, the yield stress, compression modulus, and compressive strength of the composites, were significantly influenced by the strain rates and nanosilica contents. The values of strain rate sensitivity, and dissipation energy of the composites at various strain rates, were also determined. It was found that the strain rate sensitivity, and the dissipation energy, increased with increasing strain rates. In addition, it was observed that the composites experienced more severe damage under a high strain rate loading, compared to a low strain rate loading. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Umbilical cord insertion into the lower segment of the uterus at 11 to 13 weeks' gestation is associated with maternal serum PAPP‐A
Authors: Hasegawa Junichi , Farina Antonio , Simonazzi Giuliana , Bisulli Maria , Puccetti Chiara , Pilu Gianluigi , Gabrielli Sandro , Rizzo Nicola
Published: February 2011

Objectives

To evaluate whether the location of the placental cord insertion (CI) at 11 to 13 weeks' gestation affects the maternal serum pregnancy‐associated plasma protein‐A (PAPP‐A).

Methods

Cohort study was conducted in patients who underwent the first trimester screening including nuchal translucency and blood test. We additionally documented the CI site. The thickness of the placenta under the CI and the minimum distance on the uterine wall between the internal cervical os and the CI (Dis) were measured. The subjects were divided into two groups. Below the tenth percentile in multiples of median (MoM) of Dis were defined as cases in which CI was located on the lower uterine segment (low CI) and the others were defined as controls.

Results

A total of 117 subjects were analyzed. The thickness of the placenta (r = 0.237, p = 0.010) and Dis (r = 0.243, p = 0.008) was correlated with the crown‐rump length (CRL). The maternal serum PAPP‐A MoM in the low CI group was lower than in controls (0.76 ± 0.34 vs 1.16 ± 0.55; p = 0.009), whereas the other ultrasonographic measurements and maternal demographics were not different between the two groups.

Conclusion

CI on the lower segment of the uterus is associated with low maternal serum PAPP‐A MoM levels. Copyright © 2011 John Wiley & Sons, Ltd.
Novel materials based on chitosan and cellulose
Authors: Fernandes Susana CM , Freire Carmen SR , Silvestre Armando JD , Pascoal Neto Carlos , Gandini Alessandro
Published: February 2011

This review provides a brief overview of the recent research efforts carried out at the CICECO laboratory of the University of Aveiro on novel materials based on chitosan within the background of previous investigations of similar counterparts. Most of this work is devoted to different modes of combining chitosans of various molecular weights and degrees of deacetylation (including appropriately modified chitosans providing either fluorescent properties or water solubility) with cellulose fibres of various sizes (standard to nanosize), morphologies (conventional papers, nanofibrillated or bacterial strands) and assemblies (composites or paper coating and impregnation). Additionally, the radical transformation of chitin and chitosan low‐quality residues into viscous polyols by a straightforward oxypropylation is also discussed. The results of these investigations show the remarkable potential of chitosan as a source of promising blends and composites, among other novel materials. Copyright © 2011 Society of Chemical Industry
Preparation of pH‐sensitive star‐shaped aliphatic polyesters as precursors of polymersomes
Authors: Riva Raphaël , Lazzari Wenda , Billiet Leen , Du Prez Filip , Jérôme Christine , Lecomte Philippe
Published: February 2011

This article reports on the synthesis of a new pH‐sensitive amphiphilic A2B mikto‐arm star‐shaped aliphatic copolyester [with A = poly(ε‐caprolactone) and B = tertiary amine‐bearing poly(ε‐caprolactone)] with two hydrophobic arms and one hydrophilic arm when protonated at pH = 5.5. First, the ring‐opening polymerization of ε‐caprolactone (εCL) was initiated by an aliphatic diol substituted by an alkyne. The copper(I) catalyzed azide‐alkyne cycloaddition (CuAAC) was use to convert the alkyne into a hydroxyl group prone to initiate the ring‐opening copolymerization of γ‐bromo‐ε‐caprolactone (γBrεCL) and εCL. After the substitution of the bromide atoms into azide functions, the N,N‐dimethylprop‐2‐yn‐1‐amine was grafted onto the azide bearing PCL arm by CuAAC, with the purpose to make the B arm hydrophilic at low pH. The precursors of the A2B copolymers were characterized by 1H NMR, SEC, and MALDI‐TOF. As expected, the A2B copolyester was soluble into water at pH = 5. The formation of polymersomes in water at pH 5 was assessed by DLS and TEM analyses. The effects of the architecture and the molecular weight of the A2B copolymers on the formation of polymersomes were investigated. Moreover, the versatility of our approach was demonstrated by the synthesis of an AB2 star‐shaped copolyester. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011