bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid Crystalline Polythiophenes With Amphiphilic Side Chains
Authors: Yoon Young‐Sik , Ko Taeyun , Chung Jaeyub , Chung Jae‐Seung , Kim Jin‐joo , Lee Jong‐Chan 
Published: December 2011

AbstractA series of poly(thiophene) derivatives with decyl‐oligo(oxyethylene) side groups, (PDnET) is synthesized via oxidative coupling polymerization. PD3ET and PD4ET with longer oligo(oxyethylene) units exhibited a liquid crystalline phase with well‐ordered lamella structures, although PD3ET showed a more ordered structure than PD4ET. PD1ET and PD2ET have shorter oligo(oxyethylene) groups than PD3ET and show less‐ordered structures with liquid‐crystalline phase observed. The UV‐vis spectra indicated that the maximum absorption wavelengths of PDnET increase when the number of oxyethylene units increases from 1 to 3; however, the maximum absorption wavelength of PD4ET is lower than that of PD3ET. Therefore, the most ordered and conjugated structures are obtained when the number of oxyethylene units is three.
Diabetes and pancreatic cancer
Authors: Li Donghui 
Published: December 2011

AbstractType 2 diabetes mellitus is likely the third modifiable risk factor for pancreatic cancer after cigarette smoking and obesity. Epidemiological investigations have found that long‐term type 2 diabetes mellitus is associated with a 1.5‐fold to 2.0‐fold increase in the risk of pancreatic cancer. A causal relationship between diabetes and pancreatic cancer is also supported by findings from prediagnostic evaluations of glucose and insulin levels in prospective studies. Insulin resistance and associated hyperglycemia, hyperinsulinemia, and inflammation have been suggested to be the underlying mechanisms contributing to development of diabetes‐associated pancreatic cancer. Signaling pathways that regulate the metabolic process also play important roles in cell proliferation and tumor growth. Use of the antidiabetic drug metformin has been associated with reduced risk of pancreatic cancer in diabetics and recognized as an antitumor agent with the potential to prevent and treat this cancer. On the other hand, new‐onset diabetes may indicate subclinical pancreatic cancer, and patients with new‐onset diabetes may constitute a population in whom pancreatic cancer can be detected early. Biomarkers that help define high‐risk individuals for clinical screening for pancreatic cancer are urgently needed. Why pancreatic cancer causes diabetes and how diabetes affects the clinical outcome of pancreatic cancer have yet to be fully determined. Improved understanding of the pathological mechanisms shared by diabetes and pancreatic cancer would be the key to the development of novel preventive and therapeutic strategies for this cancer. © 2011 Wiley Periodicals, Inc.
Epidemiology and potential mechanisms of tobacco smoking and heavy alcohol consumption in pancreatic cancer
Authors: Duell Eric J. 
Published: December 2011

AbstractTobacco smoking represents an important known cause of ductal pancreatic adenocarcinoma. Recent data from pooled analyses in consortia involving multiple case–control and cohort studies suggest that heavy (but not moderate or light) alcohol consumption also may increase pancreatic cancer risk. Animal and human evidence indicate that tobacco carcinogens and metabolites may act in concert and have both genetic and epigenetic effects at early and later stages in pancreatic tumorigenesis. One of the more important tobacco‐related carcinogens, NNK, probably acts via multiple pathways. Heavy alcohol consumption may increase pancreatic cancer risk by potentiating the effects of other risk factors such as tobacco smoking, poor nutrition, and inflammatory pathways related to chronic pancreatitis, but also may have independent genetic and epigenetic effects. Animal and human studies of tobacco‐ and alcohol‐related pancreatic carcinogenesis suggest multi‐modal, overlapping mechanistic pathways. Tobacco smoking and heavy alcohol consumption are preventable exposures, and their avoidance would substantially decrease the burden of pancreatic cancer worldwide. © 2011 Wiley Periodicals, Inc.
Aberrant signaling pathways in pancreatic cancer: A two compartment view
Authors: McCleary‐Wheeler Angela L. , McWilliams Robert , Fernandez‐Zapico Martin E. 
Published: December 2011

AbstractPancreatic cancer is a devastating disease with historically limited success in treatment and a poor prognosis. Pancreatic cancer appears to have a progressive pathway of development, initiating from well‐described pancreatic intraepithelial neoplasia lesions and concluding with invasive carcinoma. These early lesions have been shown to harbor‐specific alterations in signaling pathways that remain throughout this tumorigenesis process. Meanwhile, new alterations occur during this process of disease progression to have a cumulative effect. This series of events not only impacts the epithelial cells comprising the tumor, but they may also affect the surrounding stromal cells. The result is the formation of complex signaling networks of communication between the tumor epithelial cell and the stromal cell compartments to promote a permissive and cooperative environment. This article highlights some of the most common pathway aberrations involved with this disease, and how these may subsequently affect one or both cellular compartments. Consequently, furthering our understanding of these pathways in terms of their function on the tumoral epithelial and stromal compartments may prove to be crucial to the development of targeted and more successful therapies in the future. © 2011 Wiley Periodicals, Inc.
Genetic susceptibility to pancreatic cancer
Authors: Klein Alison P. 
Published: December 2011

AbstractPancreatic cancer is the fourth leading cause of cancer death in both men and women in the United States. However, it has the poorest prognosis of any major tumor type, with a 5‐yr survival rate of approximately 5%. Cigarette smoking, increased body mass index, heavy alcohol consumption, and a diagnosis of diabetes mellitus have all been demonstrated to increase risk of pancreatic cancer. A family history of pancreatic cancer has also been associated with increased risk suggesting inherited genetic factors also play an important role, with approximately 5–10% of pancreatic cancer patients reporting family history of pancreatic cancer. While the genetic basis for the majority of the familial clustering of pancreatic cancer remains unclear, several important pancreatic cancer genes have been identified. These consist of high penetrance genes includingBRCA2orPALB2, to more common genetic variation associated with a modest increase risk of pancreatic cancer such as genetic variation at theABOblood group locus. Recent advances in genotyping and genetic sequencing have accelerated the rate at which novel pancreatic cancer susceptibility genes have been identified with several genes identified within the past few years. This review addresses our current understanding of the familial aggregation of pancreatic cancer, established pancreatic cancer susceptablity genes and how this knowledge informs risk assessment and screening for high‐risk families. © 2011 Wiley Periodicals, Inc.
Semiautomated spleen volumetry with diffusion‐weighted MR imaging
Authors: Lee Jeongjin , Kim Kyoung Won , Lee Ho , Lee So Jung , Choi Sanghyun , Jeong Woo Kyoung , Kye Heewon , Song Gi‐Won , Hwang Shin , Lee Sung‐Gyu 
Published: December 2011

AbstractIn this article, we determined the relative accuracy of semiautomated spleen volumetry with diffusion‐weighted (DW) MR images compared to standard manual volumetry with DW‐MR or CT images. Semiautomated spleen volumetry using simple thresholding followed by 3D and 2D connected component analysis was performed with DW‐MR images. Manual spleen volumetry was performed on DW‐MR and CT images. In this study, 35 potential live liver donor candidates were included. Semiautomated volumetry results were highly correlated with manual volumetry results using DW‐MR (r = 0.99; P < 0.0001; mean percentage absolute difference, 1.43 ± 0.94) and CT (r = 0.99; P < 0.0001; 1.76 ± 1.07). Mean total processing time for semiautomated volumetry was significantly shorter compared to that of manual volumetry with DW‐MR (P < 0.0001) and CT (P < 0.0001). In conclusion, semiautomated spleen volumetry with DW‐MR images can be performed rapidly and accurately when compared with standard manual volumetry. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Electron paramagnetic resonance monitoring of ischemia‐induced myocardial oxygen depletion and acidosis in isolated rat hearts using soluble paramagnetic probes
Authors: Komarov Denis A. , Dhimitruka Ilirian , Kirilyuk Igor A. , Trofimiov Dmitrii G. , Grigor'ev Igor A. , Zweier Jay L. , Khramtsov Valery V. 
Published: December 2011

AbstractA new low‐field electron paramagnetic resonance approach for noninvasive measurements of myocardial oxygen tension and tissue acidity was developed. The approach was applied to monitor myocardial pO2 and pH in a model of global no‐flow ischemia (30 min) and reperfusion in isolated perfused rat hearts. The myocardial oxygen measurements were performed using deuterated Finland trityl radical probe. A rapid decrease in myocardial pO2 from 160 mmHg to about 2 ± 1 mmHg was observed within the first minute of ischemia followed by incomplete restoration of pO2 to 50 mmHg during 30 min of reperfusion. The lower oxygen concentration after ischemia was attributed to the 50% reduction in coronary flow after ischemia as a consequence of myocardial ischemia and reperfusion damage. Myocardial pH measurements using a specially designed imidazoline pH‐sensitive nitroxide showed severe myocardial acidification to pH 6.25 during 30 min of ischemia. Preconditioning of the hearts with two 5‐min periods of ischemia significantly reduced the acidification of myocardial tissue during sustained ischemia. Noninvasive electron paramagnetic resonance monitoring of myocardial oxygenation and pH may provide important insights into the mechanisms of ischemia and reperfusion injury and a background for development of new therapeutic approaches. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Correction for arterial‐tissue delay and dispersion in absolute quantitative cerebral perfusion DSC MR imaging
Authors: Mouannes‐Srour Jessy J. , Shin Wanyong , Ansari Sameer A. , Hurley Michael C. , Vakil Parmede , Bendok Bernard R. , Lee John L. , Derdeyn Colin P. , Carroll Timothy J. 
Published: December 2011

AbstractThe singular value decomposition deconvolution of cerebral tissue concentration–time curves with the arterial input function is commonly used in dynamic susceptibility contrast cerebral perfusion MR imaging. However, it is sensitive to the time discrepancy between the arrival of the bolus in the tissue concentration–time curve and the arterial input function signal. This normally causes inaccuracy in the quantitative perfusion maps due to delay and dispersion effects. A comprehensive correction algorithm has been achieved through slice‐dependent time‐shifting of the arterial input function, and a delay‐dependent dispersion correction model. The correction algorithm was tested in 11 healthy subjects and three ischemic stroke patients scanned with a quantitative perfusion pulse sequence at 1.5 T. A validation study was performed on five patients with confirmed cerebrovascular occlusive disease scanned with MRI and positron emission tomography at 3.0 T. A significant effect (P < 0.05) was reported on the quantitative cerebral blood flow and mean transit time measurements (up to 50%). There was no statistically significant effect on the quantitative cerebral blood volume values. The in vivo results were in agreement with the simulation results, as well as previous literature. This minimizes the bias in patient diagnosis due to the existing errors and artifacts in dynamic susceptibility contrast imaging. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Increase in SNR for 31P MR spectroscopy by combining polarization transfer with a direct detection sequence
Authors: van der Kemp W. J. M. , Boer V. O. , Luijten P. R. , Wijnen J. P. , Klomp D. W. J. 
Published: December 2011

AbstractThe sensitivity of 31P MRS can be increased using higher magnetic fields, but also by using 1H to 31P polarization transfer techniques where the sensitivity is determined by the polarization of the proton spins and thus the signal‐to‐noise per unit time is unaffected by the slow T1 relaxation properties of the 31P spins. This implies that 31P spins can be manipulated during the T1 relaxation of the 1H spins without affecting the signal‐to‐noise of the 1H to 31P polarization transferred spins. It is shown here that by combining 1H to 31P polarization transfer with a direct 31P detection sequence in one repetition time, one can gain more signal‐to‐noise per unit of time as compared to a polarization transfer sequence alone. Proof of principle was demonstrated by phantom measurements and additionally the method was applied to the human calf muscle and to the human breast in vivo at 7T. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Detection of osteoarthritis in knee and hip joints by fast field‐cycling NMR
Authors: Broche Lionel M. , Ashcroft George P. , Lurie David J. 
Published: December 2011

AbstractIt is known that in the early stages of osteoarthritis, the concentration of glycan proteins decreases in articular cartilage. This phenomenon is under active research to develop a means to characterize osteoarthritis accurately in the early stages of the disease, when still reversible. However, no method of quantification has yet shown clear success in this area. In this article, we propose a novel approach to detect glycan depletion using fast field‐cycling NMR. This technique was previously reported to allow noninvasive measurement of protein concentration via the 14N quadrupolar relaxation in certain amide groups. We have demonstrated that the articular cartilage exhibits clear quadrupolar peaks that can be measured by a benchtop fast field‐cycling NMR device and which changes significantly between normal and diseased tissues (P < 0.01). This signal is probably glycan specific. The method may have potential for early evaluation of osteoarthritis in patients on fast field‐cycling‐MRI scanners currently under evaluation in the authors' laboratory. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Quantitative in vivo diffusion imaging of cartilage using double echo steady‐state free precession
Authors: Bieri Oliver , Ganter Carl , Scheffler Klaus 
Published: December 2011

AbstractSingle‐shot echo‐planar imaging techniques are commonly used for diffusion‐weighted imaging (DWI) but offer rather poor spatial resolution and field‐of‐view coverage for species with short T2. In contrast, steady‐state free precession (SSFP) has shown promising results for DWI of the musculoskeletal system, but quantification is generally hampered by its prominent sensitivity on relaxation times. In this work, a new and truly diffusion‐weighted (that is relaxation time independent) SSFP DWI technique is introduced using a double‐echo steady‐state approach. Within this framework (and this is in contrast to common SSFP DWI techniques using SSFP‐Echo) both primary echo paths of nonbalanced SSFP are acquired, namely the FID and the Echo. Simulations and in vitro measurements reveal that the ratio of the Echo/FID signal ratios of two double‐echo steady‐state scans acquired with and without diffusion sensitizing dephasing moments provides a highly relaxation independent quantity for diffusion quantification. As a result, relaxation‐independent high‐resolution (0.4 × 0.4 − 0.6 × 0.6 mm2 in‐plane resolution) quantitative in vivo SSFP DWI is demonstrated for human articular cartilage using diffusion‐weighted double‐echo steady‐state scans in the knee and ankle joint at 3.0 T. The derived diffusion coefficients for cartilage (D ∼ 1.0–1.5 μm2/ms) and synovial fluid (D ∼ 2.6 μm2/ms) are in agreement with previous work. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Measuring brain oxygenation in humans using a multiparametric quantitative blood oxygenation level dependent MRI approach
Authors: Christen Thomas , Schmiedeskamp Heiko , Straka Matus , Bammer Roland , Zaharchuk Greg 
Published: December 2011

AbstractQuantitative blood oxygenation level dependent approaches have been designed to obtain quantitative oxygenation information using MRI. A mathematical model is usually fitted to the time signal decay of a gradient‐echo and spin‐echo measurements to derive hemodynamic parameters such as the blood oxygen saturation or the cerebral blood volume. Although the results in rats and human brain have been encouraging, recent studies have pointed out the need for independent estimation of one or more variables to increase the accuracy of the method. In this study, a multiparametric quantitative blood oxygenation level dependent approach is proposed. A combination of arterial spin labeling and dynamic susceptibility contrast methods were used to obtain quantitative estimates of cerebral blood volume and cerebral blood flow. These results were combined with T and T2 measurements to derive maps of blood oxygen saturation or cerebral metabolic rate of oxygen. In 12 normal subjects, a mean cerebral blood volume of 4.33 ± 0.7%, cerebral blood flow of 43.8 ± 5.7 mL/min/100 g, blood oxygen saturation of 60 ± 6% and cerebral metabolic rate of oxygen 157 ± 23 μmol/100 g/min were found, which are in agreement with literature values. The results obtained in this study suggest that this methodology could be applied to study brain hypoxia in the setting of pathology. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
A piezoelectric 3D hexahedral curvilinear finite element based on the space fiber rotation concept
Authors: Zouari Wajdi , Ayad Rezak , Zineb Tarak Ben , Benjeddou Ayech 
Published: December 2011

SUMMARYThe paper is focused on a piezoelectric 3D hexahedral finite element formulation on the basis of the space fiber rotation concept. The proposed electromechanical finite element has eight nodes and is animated by the virtual rotation of an elementary spatial fiber that creates an additional mechanical displacement enhancing the classical one generally considered to formulate the standard solid elements. The mechanical strain tensor and the electric field vector are expressed in a curvilinear coordinate system to handle the transverse isotropy behavior of piezoelectric materials. Numerical examples demonstrate that the proposed electromechanical element is less sensitive to mesh distortion than the standard piezoelectric solid elements. Besides, it is shown that the developed element response is better than those of the standard first‐order piezoelectric elements. Copyright © 2011 John Wiley & Sons, Ltd.
Four‐node mixed Hu–Washizu shell element with drilling rotation
Authors: Wisniewski K. , Turska E. 
Published: December 2011

SUMMARYIn this paper, enhanced four‐node shell elements with six DOFs/node based on the Hu–Washizu (HW) functional are developed for Green strain. The drilling rotation is included through the drilling rotation constraint equation. The key features of the approach are as follows.

The shell HW functional is derived from the shell potential energy functional, which is an alternative to the derivation from the three‐dimensional HW functional. This method is more versatile as it enables the derivation of the so‐called partial HW functionals, with different treatment of the bending/twisting part and the transverse shear part of strain energy.
For the membrane part of HW shell elements, a seven‐parameter stress, a nine‐parameter strain and a two‐parameter enhanced assumed displacement gradient enhancement are selected as optimal. The assumed representations of stress and strain are defined in skew coordinates in the natural basis at the element's center. This improves accuracy and has positive theoretical consequences.
The drilling rotation constraint equation is treated by the perturbed Lagrange method. The faulty term resulting from the equal‐order approximations of displacements and the drilling rotation is eliminated, and one spurious mode is stabilized using the gamma method. The proposed formulation is insensitive to the element's distortions and yields a large radius of convergence in the examples involving in‐plane bending.The performance of 4 four‐node shell HW elements, having different bending/twisting and transverse shear parts, is analyzed on several numerical examples. Such aspects are considered as: accuracy, radius of convergence, required number of iterations of the Newton method or the arc‐length method and time of computations. The element with 29 parameters (HW29) is selected as the best performer. Copyright © 2011 John Wiley & Sons, Ltd.
Couple functioning and post‐traumatic stress symptoms in US army couples: The role of resilience
Authors: Melvin Kristal C. , Gross Deborah , Hayat Matthew J. , Jennings Bonnie Mowinski , Campbell Jacquelyn C. 
Published: December 2011

AbstractThe purpose of this study was to investigate combat‐related post‐traumatic stress symptoms (PTSS) and couple relationships in Army couples. US Army combat veteran couples (N = 66 couples) completed self‐report questionnaires on couple functioning, coercion, resilience, and PTSS. In 23% of the couples (n = 15), both members had PTSS above the clinical cut‐off for suspected Post‐traumatic Stress Disorder (PTSD). Higher levels of PTSS were associated with lower couple functioning and resilience. Individuals with high resilience scores reported higher couple functioning scores, regardless of PTSS (p = .004). Future researchers should focus on the role of resilience in relation to couple functioning, and ways to amplify resilience in military couples. Published 2011. This article is a U.S. Government work and is in the public domain in the USA. Res Nurs Health 35:164–177, 2012
Modern Raman spectroscopy for biomedical applications
Authors: Popp Jürgen , Krafft Christoph , Mayerhöfer Thomas 
Published: December 2011

AbstractBacteria identification by conventional methods still requires too much time, metastasis is often detected too late and generally too much healthy tissue around a tumor must be excised as the tumor borders cannot be detected with the necessary precision and reliability. Apart from being yet unsolved but urgent and important medical problems these three examples have a potential solution in common, being delivered by the application of Raman spectroscopy. In the following we present how this label‐free method can complement or even replace standard but unsatisfying medical procedures in the future.
Attosecond Physics – the first decade
Authors: Naeser Thorsten 
Published: December 2011

AbstractDeep inside matter, our ideas of time lose their validity. Light flashes which last only a few millionths to billionths of a billionth second snatch from the microcosm its closely guarded secrets: Electron movements become visible. Quantum phenomena can be examined in real time. The control of elementary particles comes within reach. Responsible for all that is the young science of attosecond physics, „born”︁ in 2001, when Prof. Ferenc Krausz succeeded in producing and measuring light flashes which last less than one femtosecond. Krausz founded the Laboratory for Attosecond Physics (LAP) which is located at the Max Planck Institute for Quantum Optics in Garching, Germany. Here is the history of how Attosecond Physics has been developed in LAP over the last ten years.