bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of the Pyridine 3‐Substituent on Regioselectivity in the Nucleophilic Aromatic Substitution Reaction of 3‐Substituted 2,6‐Dichloropyridines with 1‐Methylpiperazine Studied by a Chemical Design Strategy
Authors: Bach Peter , Marczynke Michaela , Giordanetto Fabrizio 
Published: November 2012

AbstractA chemical design strategy has been used to select 3‐substituted 2,6‐dichloropyridines for the nucleophilic aromatic substitution reaction with 1‐methylpiperazine. The aim was to study the dependency of the regioselectivity in these reactions on the character of the pyridine 3‐substituent expressed by their lipophilicity (PI), size (MR), and inductive effect (σp). Interestingly, the regioselectivity did not correlate with any of these parameters, but in a statistically significant manner with the Verloop steric parameter B1, as indicated by the p value of 0.006 (R2 = 0.45). This implies that bulky 3‐substituents close to the pyridine ring induce regioselectivity towards the 6‐position. Useful in practical synthesis is the different regioselectivity obtained with a carboxylic acid 3‐substituent and precursors or derivatives thereof. Thus, in acetonitrile as solvent, 3‐carboxylate and 3‐amide substituents were preferred to obtain the 2‐isomer (9:1 ratio of the 6‐isomer), whereas the 3‐cyano and 3‐trifluoromethyl substitutents were preferred to obtain the 6‐isomer (9:1 ratio of the 2‐isomer). Analysis of the regioselectivity Rsel for the pyridine 2‐position in the reaction of 2,6‐dichloro‐3‐(methoxycarbonyl)pyridine with 1‐methylpiperazine in 21 different solvents showed that Rsel could be predicted by the Kamlet–Taft equation: Rsel = 1.28990 + 0.03992α – 0.59417β – 0.46169π* (R2 = 0.95, p = 1.9 × 10–10). Rsel is thus mainly correlated with the ability of the solvent to function as a hydrogen‐bond acceptor, as expressed by the solvatochromic β parameter. Thus, the 16:1 regioselectivity for the 2‐isomer in DCM (β = 0.10) could be switched to a 2:1 selectivity for the 6‐isomer in DMSO (β = 0.76).
Gravel‐bed rivers: from particles to patterns
Authors: Ashmore Peter E. , Rennie Colin D. 
Published: November 2012

ABSTRACTThe papers in this special issue reflect several of the major themes and topics from the 7th International Workshop on Gravel‐Bed Rivers. The papers focus primarily on aspects of bed material transport in gravel‐bed rivers and larger scale morpho‐dynamics. Research in gravel‐bed rivers is increasingly integrating processes over a wide range of temporal and spatial scales by combining field observation, lab experimentation, numerical modeling and theory testing in a range of river types, aided by new technological developments in particle tracking, computational modeling and high resolution spatial data. This is leading to greater understanding of the processes leading to distinctive morpho‐dynamics of river types and a more reliable basis for river management. Copyright © 2012 John Wiley & Sons, Ltd.
HCC Is promoted by bacterial translocation and TLR-4 signaling: A new paradigm for chemoprevention and management
Authors: Toffanin Sara , Cornella Helena , Harrington Andrew , Llovet Josep M. , Groszmann Roberto J. , Iwakiri Yasuko , Taddei Tamar H. 
Published: November 2012

Abstract

Increased translocation of intestinal bacteria is a hallmark of chronic liver disease and contributes to hepatic inflammation and fibrosis. Here we tested the hypothesis that the intestinal microbiota and Toll-like receptors (TLRs) promote hepatocellular carcinoma (HCC), a long-term consequence of chronic liver injury, inflammation, and fibrosis. Hepatocarcinogenesis in chronically injured livers depended on the intestinal microbiota and TLR4 activation in non-bone-marrow-derived resident liver cells. TLR4 and the intestinal microbiota were not required for HCC initiation but for HCC promotion, mediating increased proliferation, expression of the hepatomitogen epiregulin, and prevention of apoptosis. Gut sterilization restricted to late stages of hepatocarcinogenesis reduced HCC, suggesting that the intestinal microbiota and TLR4 represent therapeutic targets for HCC prevention in advanced liver disease.
Lattice Boltzmann simulation of mixed convection heat transfer in a corrugated wall cavity utilizing water‐based nanofluids
Authors: Jafari Mohammad , Farhadi Mousa , Sedighi Kurosh , Mehrizi Abbas Ali Abouei 
Published: November 2012

AbstractIn the present study, the effects of Cu and CuO nanoparticles' presence on mixed convection heat transfer in a lid‐driven cavity with a corrugated wall are investigated using the lattice Boltzmann method. The boundary fitting method with second‐order accuracy at both velocity and temperature fields is used to simulate the curved boundaries in the LBM. The problem is investigated for different Richardson numbers (0.1–10), volume fractions of nanoparticles (0–0.05), curve amplitudes (0.05–0.25), and phase shifts of corrugated wall (0–270) when the Reynolds number is equal to 25. The volume fraction of added nanoparticles to the water‐based fluid is less than 0.05 to make dilute suspensions. Results show that adding nanoparticles enhances the rate of heat transfer. It is found that nanoparticles have significant effects on both fluid flow and heat transfer of the mixed convection, especially for low Richardson numbers. A comparison between Cu and CuO nanoparticles shows the Cu nanoparticles have a better effect on heat transfer enhancement for all tested conditions. The results also represent the effective role of a corrugated wall on the rate of nanofluid heat transfer. It is observed that increasing the wavy wall's amplitude leads to a decrease of the average Nusselt numberfor a high Richardson number. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21024
Mdm2 inhibitors synergize with topoisomerase II inhibitors to induce p53‐independent pancreatic cancer cell death
Authors: Conradt Laura , Henrich Annika , Wirth Matthias , Reichert Maximilian , Lesina Marina , Algül Hana , Schmid Roland M. , Krämer Oliver H. , Saur Dieter , Schneider Günter 
Published: November 2012

AbstractPancreatic ductal adenocarcinoma (PDAC) represents the fourth leading cause of cancer death in the western world, with a 5‐year survival rate below 5%. Murine double minute 2 (Mdm2) is an important negative regulator of the tumor suppressor p53. Reactivation of wild‐type p53 is a promising treatment strategy, and inhibitors of Mdm2 have already entered clinical trials. To investigate the effects of Mdm2 inhibitors in PDAC, we used a murine cell line platform with a genetically defined status of p53. Here, we describe that Mdm2 inhibitors can act on a subset of murine PDAC cell lines p53 independently. Furthermore, we observed that Mdm2 inhibitors increase the sensitivity of murine PDAC cell lines toward topoisomerase II inhibitors by inducing effector caspase‐independent cell death. The combination of Mdm2 inhibitors with topoisomerase II inhibitors acts independent of the survival factor NFκB/RelA. Mechanistically, Mdm2 inhibitors increase topoisomerase II inhibitor‐induced DNA double‐strand breaks. We show that Mdm2 binds to Nbs1 of the Mre11–Rad50–Nijmegen breakage syndrome (Nbs) 1 DNA repair complex. In addition, we provide evidence that Mdm2 inhibitors delay DNA repair. These findings may help to design novel therapeutic strategies to overcome therapeutic resistance of PDAC.
Unmixing functional magnetic resonance imaging data using matrix factorization
Authors: Khaliq Amir A. , Qureshi Ijaz M. , Shah Jawad A. 
Published: November 2012

AbstractFunctional magnetic resonance imaging (fMRI) data is processed by different techniques for detection of activated voxels including principal component analysis (PCA), independent component analysis (ICA), non‐negative matrix factorization (NMF), and so on. In this work, a modified version of NMF method is proposed in which data is not supposed to be non‐negative. The proposed scheme is applied to synthetic fMRI data along with NMF conventional method. The results of the proposed scheme show that it is not only computationally efficient but also has good quality results as compared to that of NMF in terms of average correlation. Finally, proposed method is applied to monkey's fMRI data, and the results are compared with that of NMF and ICA. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 195–199, 2012
Study of X‐Ray Imaging with Toroidally Bent Crystal
Authors: Shi Jun , Xiao Shali , Liu Lifeng , Wu Yufen 
Published: November 2012

ABSTRACTWe developed a focusing imager with a toroidally bent crystal imager. The imager can be used in X‐ray imaging of laser fusion experiments. This article discusses the focusing properties of toroidally bent crystal in Bragg geometry. Simulations of spatial resolution for toroidally bent crystals with different conditions including source size and detector position were done using the ray‐tracing method. The applicable conditions for optimized two‐dimensional (2D) imaging of X‐ray source are proposed. Toroidally bent crystal of mica with curvature radius 290 mm in the meridional plane and 190 mm in the sagittal plane is used as imaging element in the experiments. The high‐quality visible 2D X‐ray image was obtained with the imaging plate due to the high collection efficiency of the bent crystal imaging system. It is demonstrated that the toroidally bent mica crystal could be used in X‐ray imaging. By analyzing the image information of the sagittal direction, we find out that the toroidal crystal imager has spatial resolution about 34 µm.
Clinical value of cardiac I‐123 metaiodobenzylguanidine scintigraphy between Parkinson's disease and Parkinson's disease associated dementia
Authors: Song In‐Uk , Chung Yong‐An , Chung Sung‐Woo , Huh Ryoong 
Published: November 2012

AbstractIt is very difficult that idiopathic Parkinson's disease (PD) patients with dementia (PDD) distinguish from PD patients, because PD patients may exhibit patterns of cognitive impairment. Recently, cardiac I‐123 metaiodobenzylguanidine (MIBG) scintigraphy has been used as tools to distinguish PD from atypical parkinsonism. Thus, we performed this study to confirm significant clinical value of cardiac I‐123 MIBG scintigraphy for differential diagnosis between PD and PDD. Cardiac I‐123 MIBG scintigraphy was studied in 18 patients with PD, 18 patients with PDD, and 13 normal controls that were matched for age, disease duration, and severity of symptoms. The heart to mediastinum ratio (H/M ratio) was calculated. The mean value of H/M ratio of PDD and PD was significantly lower than normal controls. However, there were no differences between PDD and PD groups. Although cardiac I‐123 MIBG scintigraphy did not distinguish PDD from PD, we wish to focus attention on sustained studies that are needed to differentiate other Lewy body disease from many dementia patients with PD features. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 241–244, 2012
Assessment of testicular uptake in flourine‐18 fluorodeoxyglucose positron emission tomography/computed tomography
Authors: Han Eun Ji , Lee Sang‐Hoon , Sohn Hyung Sun , Chung Yong‐An , Chung Soo Kyo 
Published: November 2012

AbstractThe testis shows physiologic uptake in flourine‐18 fluorodeoxyglucose (F‐18 FDG) positron emission tomography (PET). The purpose of this study was to examine the degree of FDG uptake of normal testis on PET/computed tomography (CT), especially in relationship to various clinical parameters. We obtained the maximum standardized uptake value (SUVmax) and the mean standardized uptake value (SUVmean) of each testis from PET/CT of 166 healthy men. We also calculated the testis‐to‐muscle (T/M) ratio, defined as the SUVmean of the testis divided by the SUVmean of the right thigh muscle. Subjects completed a questionnaire on their medical history and sexual habits, including frequency of sexual intercourse, latest date of sexual intercourse, and vasectomy history. We then evaluated the association between imaging parameters and sexual habits. The mean age of subjects was 48 ± 10 years (range, 21–74), and the mean volume of each testis was 17.1 ± 4.5 cm3 (range, 7.4–32.4). The mean SUVmax was 3.6 ± 0.5 (range, 2.2–5.5), the mean SUVmean was 2.5 ± 0.4 (range, 1.6–3.8), and the mean T/M ratio was 4.2 ± 0.8 (range, 2.3–7.3). Of the 166 subjects, 51 reported having sexual intercourse zero times per month and 109 had sexual intercourse at least per month. The interval between the latest date of sexual intercourse and PET/CT was less than 3 days in 48 subjects; between 3 days and 1 month in 58; and greater than 1 month in 60. Twenty subjects were currently vasectomized. The T/M ratio was significantly correlated with age (P = 0.040) but not with sexual habits. On the PET/CT, normal testicular FDG uptake decreased as age increased. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 245–249, 2012
Diversity patterns and food web structure in a Mediterranean intermittent stream
Authors: López‐Rodríguez Manuel J. , Peralta‐Maraver Ignacio , Gaetani Brunella , Sainz‐Cantero Carmen E. , Fochetti Romolo , de Figueroa J. Manuel Tierno 
Published: November 2012

AbstractIn this work we present the results of a one‐year study on the macroinvertebrate community in an intermittent stream in southern Spain. We have studied the taxonomic composition, diversity and food web monthly in order to consider temporal variability in these parameters. More than 60 macroinvertebrate taxa have been recorded in the stream, but they do not cohabit at the same time. Many of them join the community at the beginning of the wet period. Afterwards, some new taxa incorporate but some others disappear. This leads to huge fluctuations in the diversity of the community and in the food web of different sampling dates. These variations are linked to environmental disturbances, mainly to flow peaks and minimums. From a relatively well structured, but simple, food web at the beginning of the wet period, it can be seen how several trophic levels disappear with time, and how several organisms change or extend their trophic function within it. We relate these variations to the intermediate disturbance hypothesis and discuss the resilience of the community of this intermittent stream (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rate coefficients of the CF3CHFCF3 + H → CF3CFCF3 + H2 reaction at different temperatures calculated by transition state theory with ab initio and DFT reaction paths
Authors: Ng Maggie , Mok Daniel K. W. , Lee Edmond P. F. , Dyke John M. 
Published: November 2012

AbstractThe minimum energy path (MEP) of the reaction, CF3CHFCF3 + H → transition state (TS) → CF3CFCF3 + H2, has been computed at different ab initio levels and with density functional theory (DFT) using different functionals. The computed B3LYP/6‐31++G**, BH&HLYP/cc‐pVDZ, BMK/6‐31++G**, M05/6‐31+G**, M05‐2X/6‐31+G**, UMP2/6‐31++G**, PUMP2/6‐31++G**//UMP2/6‐31++G**, RCCSD(T)/aug‐cc‐pVDZ//UMP2/6‐31++G**, RCCSD(T)/aug‐cc‐pVTZ(spd,sp)//UMP2//6‐31++G**, RCCSD(T)/CBS//M05/6‐31+G**, and RCCSD(T)/CBS//UMP2/6‐31++G** MEPs, and associated gradients and Hessians, were used in reaction rate coefficient calculations based on the transition state theory (TST). Reaction rate coefficients were computed between 300 and 1500 K at various levels of TST, which include conventional TST, canonical variational TST (CVT) and improved CVT (ICVT), and with different tunneling corrections, namely, Wigner, zero‐curvature, and small‐curvature (SCT). The computed rate coefficients obtained at different ab initio, DFT and TST levels are compared with experimental values available in the 1000–1200 K temperature range. Based on the rate coefficients computed at the ICVT/SCT level, the highest TST level used in this study, the BH&HLYP functional performs best among all the functionals used, while the RCCSD(T)/CBS//MP2/6‐31++G** level is the best among all the ab initio levels used. Comparing computed reaction rate coefficients obtained at different levels of theory shows that, the computed barrier height has the strongest effect on the computed reaction rate coefficients as expected. Variational effects on the computed rate coefficients are found to be negligibly small. Although tunneling effects are relatively small at high temperatures (∼1500 K), SCT corrections are significant at low temperatures (∼300 K), and both barrier heights and the magnitudes of the imaginary frequencies affect SCT corrections. © 2012 Wiley Periodicals, Inc.
An accurate and efficient method to predict the electronic excitation energies of BODIPY fluorescent dyes
Authors: Wang Jia‐Nan , Jin Jun‐Ling , Geng Yun , Sun Shi‐Ling , Xu Hong‐Liang , Lu Ying‐Hua , Su Zhong‐Min 
Published: November 2012

AbstractRecently, the extreme learning machine neural network (ELMNN) as a valid computing method has been proposed to predict the nonlinear optical property successfully (Wang et al., J. Comput. Chem. 2012, 33, 231). In this work, first, we follow this line of work to predict the electronic excitation energies using the ELMNN method. Significantly, the root mean square deviation of the predicted electronic excitation energies of 90 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) derivatives between the predicted and experimental values has been reduced to 0.13 eV. Second, four groups of molecule descriptors are considered when building the computing models. The results show that the quantum chemical descriptions have the closest intrinsic relation with the electronic excitation energy values. Finally, a user‐friendly web server (EEEBPre: Prediction of electronic excitation energies for BODIPY dyes), which is freely accessible to public at the web site: http://202.198.129.218, has been built for prediction. This web server can return the predicted electronic excitation energy values of BODIPY dyes that are high consistent with the experimental values. We hope that this web server would be helpful to theoretical and experimental chemists in related research. © 2012 Wiley Periodicals, Inc.
Calculating standard reduction potentials of [4Fe–4S] proteins
Authors: Perrin Bradley Scott , Niu Shuqiang , Ichiye Toshiko 
Published: November 2012

AbstractThe oxidation–reduction potentials of electron transfer proteins determine the driving forces for their electron transfer reactions. Although the type of redox site determines the intrinsic energy required to add or remove an electron, the electrostatic interaction energy between the redox site and its surrounding environment can greatly shift the redox potentials. Here, a method for calculating the reduction potential versus the standard hydrogen electrode, E°, of a metalloprotein using a combination of density functional theory and continuum electrostatics is presented. This work focuses on the methodology for the continuum electrostatics calculations, including various factors that may affect the accuracy. The calculations are demonstrated using crystal structures of six homologous HiPIPs, which give E° that are in excellent agreement with experimental results. © 2012 Wiley Periodicals, Inc.
Shared Pathogeneses of Posttrauma Pathologies: Attachment, Emotion Regulation, and Cognitions
Authors: Lilly Michelle M. , Hong (Phylice) Lim Ban 
Published: November 2012

ObjectiveTo demonstrate how intrapersonal functioning variables related to attachment, cognition, and emotion are implicated in mental health outcomes for two samples of interpersonal trauma survivors, including undergraduates and women from the community.MethodTwo samples of survivors of interpersonal trauma were included: undergraduates (n = 290, 60% female) and intimate partner violence survivors from the community (n = 114). Participants completed self‐report measures that assessed psychopathology, emotion dysregulation, attachment processes, and cognitions about the world, self, and others.ResultsEmotion dysregulation was strongly linked to symptoms of depression, posttraumatic stress disorder, and somatization in both samples. Cognitions also accounted for unique variance in predicting symptoms of depression and somatization in both samples.ConclusionsResults suggest that disruption in the ability to regulate emotions is the most consistent predictor of mental health in survivors of interpersonal trauma, followed by cognitions regarding the world, self, and others. Treatment implications are discussed.
Software for automated MRI‐based quantification of abdominal fat and preliminary evaluation in morbidly obese patients
Authors: Thörmer Gregor , Bertram Henriette Helene , Garnov Nikita , Peter Veronika , Schütz Tatjana , Shang Edward , Blüher Matthias , Kahn Thomas , Busse Harald 
Published: November 2012

AbstractPurpose:To present software for supervised automatic quantification of visceral and subcutaneous adipose tissue (VAT, SAT) and evaluates its performance in terms of reliability, interobserver variation, and processing time, since fully automatic segmentation of fat‐fraction magnetic resonance imaging (MRI) is fast but susceptible to anatomical variations and artifacts, particularly for advanced stages of obesity.Materials and Methods:Twenty morbidly obese patients (average BMI 44 kg/m2) underwent 1.5‐T MRI using a double‐echo gradient‐echo sequence. Fully automatic analysis (FAA) required no user interaction, while supervised automatic analysis (SAA) involved review and manual correction of the FAA results by two observers. Standard of reference was provided by manual segmentation analysis (MSA).Results:Average processing times per patient were 6, 6+4, and 21 minutes for FAA, SAA, and MSA (P < 0.001), respectively. For VAT/SAT assessment, Pearson correlation coefficients, mean (bias), and standard deviations of the differences were R = 0.950, +0.003, and 0.043 between FAA and MSA and R = 0.981, +0.009, and 0.027 between SAA and MSA. Interobserver variation and intraclass correlation were 3.1% and 0.996 for SAA, and 6.6% and 0.986 for MSA, respectively.Conclusion:The presented supervised automatic approach provides a reliable option for MRI‐based fat quantification in morbidly obese patients and was much faster than manual analysis. J. Magn. Reson. Imaging 2013;37:1144–1150. © 2012 Wiley Periodicals, Inc.
Copper signaling in the mammalian nervous system: Synaptic effects
Authors: Gaier E.D. , Eipper B.A. , Mains R.E. 
Published: November 2012

AbstractCopper is an essential metal present at high levels in the CNS. Its role as a cofactor in mitochondrial ATP production and in essential cuproenzymes is well defined. Menkes and Wilson's diseases are severe neurodegenerative conditions that demonstrate the importance of Cu transport into the secretory pathway. In the brain, intracellular levels of Cu, which is almost entirely protein bound, exceed extracellular levels by more than 100‐fold. Cu stored in the secretory pathway is released in a Ca2+‐dependent manner and can transiently reach concentrations over 100 μM at synapses. The ability of low micromolar levels of Cu to bind to and modulate the function of γ‐aminobutyric acid type A (GABAA) receptors, N‐methyl‐D‐aspartate (NMDA) receptors, and voltage‐gated Ca2+ channels contributes to its effects on synaptic transmission. Cu also binds to amyloid precursor protein and prion protein; both proteins are found at synapses and brain Cu homeostasis is disrupted in mice lacking either protein. Especially intriguing is the ability of Cu to affect AMP‐activated protein kinase (AMPK), a monitor of cellular energy status. Despite this, few investigators have examined the direct effects of Cu on synaptic transmission and plasticity. Although the variability of results demonstrates complex influences of Cu that are highly method sensitive, these studies nevertheless strongly support important roles for endogenous Cu and new roles for Cu‐binding proteins in synaptic function/plasticity and behavior. Further study of the many roles of Cu in nervous system function will reveal targets for intervention in other diseases in which Cu homeostasis is disrupted. © 2012 Wiley Periodicals, Inc.