bluuebunny/crossref_metadata_2025_split huggingface dataset:
18F‐Labeling of Sensitive Biomolecules for Positron Emission Tomography
Authors: Krishnan Hema S. , Ma Longle , Vasdev Neil , Liang Steven H. 
Published: July 2017

AbstractPositron emission tomography (PET) imaging study of fluorine‐18 labeled biomolecules is an emerging and rapidly growing area for preclinical and clinical research. The present review focuses on recent advances in radiochemical methods for incorporating fluorine‐18 into biomolecules via “direct” or “indirect” bioconjugation. Recently developed prosthetic groups and pre‐targeting strategies, as well as representative examples in 18F‐labeling of biomolecules in PET imaging research studies are highlighted.
Determination of the Absolute Configuration of (−)‐Hydroxynitrilaphos and Related Biosynthetic Questions
Authors: Pallitsch Katharina , Happl Barbara , Stieger Christian 
Published: July 2017

AbstractThe ongoing search for bioactive natural products has led to the development of new genome‐based screening approaches to identify possible phosphonate producing microorganisms. From the identified phosphonate producers, several until now unknown phosphonic acid natural products were isolated, including (hydroxy)nitrilaphos (4 and 5) and (hydroxy)phosphonocystoximate (7 and 6). We present the synthesis of phosphonocystoximate via an aldoxime intermediate. Chlorination and coupling with methyl N‐acetylcysteinate furnished 6 after global deprotection. The obtained experimental data confirm the previously assigned structure of the natural product. We were also able to determine the absolute configuration of (−)‐hydroxynitrilaphos. Chiral resolution of diethyl cyanohydroxymethylphosphonate (24) with Noe's lactol furnished both enantiomers of 4. Conversion of (+)‐24 to (R)‐2‐amino‐1‐hydroxyethylphosphonic acid by reduction of the cyano‐group showed (−)‐hydroxynitrilaphos ultimately to be S‐configured. Further, we present a 13C‐isotope labeling strategy for 4 and 5 that will possibly solve the question of whether hydroxynitrilaphos is a biosynthetic intermediate or a downstream product of hydroxyphosphonocystoximate biosynthesis.
A Combined 1H/6Li NMR DOSY Strategy Finally Uncovers the Structure of Isopropyllithium in THF
Authors: Barozzino‐Consiglio Gabriella , Hamdoun Ghanem , Fressigné Catherine , Harrison‐Marchand Anne , Maddaluno Jacques , Oulyadi Hassan 
Published: July 2017

AbstractDespite its common use in synthesis, the structure of isopropylliyhium in THF has never been determined, a dimer being generally proposed but not supported. This paper fills this data gap through a sophisticated NMR study that shows that, in THF at low‐temperature, isopropyllithium is in the form of a 1:2 mixture of a trisolvated monomer and a disolvated dimer in equilibrium. The presence of the monomer, never evoked before, together with a hypo‐solvation of the dimer hinted by DFT calculations, provides a rational explanation to the remarkable reactivity of this organolithium reagent in ethereal solvents.
MnCl2‐Catalyzed C−H Alkylations with Alkyl Halides
Authors: Liu Weiping , Cera Gianpiero , Oliveira João C. A. , Shen Zhigao , Ackermann Lutz 
Published: July 2017

AbstractC−H alkylations with challenging β‐hydrogen‐containing alkyl halides were accomplished with sustainable MnCl2 as the catalyst under phosphine‐ligand‐free conditions. The proximity‐induced benzamide C−H activation occurred with ample substrate scope through rate‐determining C−H metalation, also setting the stage for manganese‐catalyzed oxidative C−H methylations.
Assessment of Density Functionals for Computing Thermodynamic Properties of Lanthanide Complexes
Authors: Jaoul Arnaud , Nocton Grégory , Clavaguéra Carine 
Published: July 2017

AbstractThe equilibrium between the radical phenanthroline complex Cp*2Sm(phen) and the coupling product (Cp*2Sm(phen))2has been investigated based on quantum chemistry calculations. Topological analyses pointed out that the C−C bond created has a partial covalent character, explaining why both the monomeric and the dimeric forms exist in equilibrium. A large variety of density functionals have been tested to reproduce experimental thermodynamic data for this equilibrium. Finally, the PBE0‐D3 and M06‐2X functionals lead to a good evaluation of the energies and enable a correct description of the ligand to metal charge transfer, both in the 4f and 5d metal orbitals.
Novel chemiluminescent Western blot blocking and antibody incubation solution for enhanced antibody‐antigen interaction and increased specificity
Authors: Schwartz Kimberly , Bochkariov Dmitry 
Published: July 2017

AbstractWestern blotting is a ubiquitous tool used in protein and molecular biology research, providing information about the presence, size, relative abundance, and state of a protein in a mixture. First, the proteins in a sample are separated by size using SDS‐PAGE then transferred onto a membrane for detection with a set of primary and secondary antibodies. High‐quality Western data requires high signal‐to‐noise ratios, which depend upon reduction of nonspecific antibody interactions. Blocking is a critical step in the Western blot method as it prevents the antibodies from binding nonspecifically to the membrane and irrelevant proteins. A solution of nonfat dry milk (NFDM) in physiological buffer is commonly used for this purpose, but does not perform well with every type of antibody and is not optimal for low‐abundance proteins. We present a novel blocking solution for chemiluminescent Western blots, AdvanBlock™‐chemi, which outperforms NFDM in experiments with 20 unique antibodies by increasing signal‐to‐noise ratios and minimizing nonspecific binding. This solution enhances protein detection by Western blot and provides consistent results for detection of low abundant and modified proteins.
BMP‐ and TGFβ‐signaling regulate the formation of Müller glia‐derived progenitor cells in the avian retina
Authors: Todd Levi , Palazzo Isabella , Squires Natalie , Mendonca Ninoshka , Fischer Andy J. 
Published: July 2017

AbstractMüller glia‐derived progenitor cells (MGPCs) have the capability to regenerate neurons in the retinas of different vertebrate orders. The formation of MGPCs is regulated by a network of cell‐signaling pathways. The purpose of this study was to investigate how BMP/Smad1/5/8‐ and TGFβ/Smad2/3‐signaling are coordinated to influence the formation of MGPCs in the chick model system. We find that pSmad1/5/8 is selectively up‐regulated in the nuclei of Müller glia following treatment with BMP4, FGF2, or NMDA‐induced damage, and this up‐regulation is blocked by a dorsomorphin analogue DMH1. By comparison, Smad2/3 is found in the nuclei of Müller glia in untreated retinas, and becomes localized to the cytoplasm following NMDA‐ or FGF2‐treatment. These findings suggest a decrease in TGFβ‐ and increase in BMP‐signaling when MGPCs are known to form. In both NMDA‐damaged and FGF2‐treated retinas, inhibition of BMP‐signaling suppressed the proliferation of MGPCs, whereas inhibition of TGFβ‐signaling stimulated the proliferation of MGPCs. Consistent with these findings, TGFβ2 suppressed the formation of MGPCs in NMDA‐damaged retinas. Our findings indicate that BMP/TGFβ/Smad‐signaling is recruited into the network of signaling pathways that controls the formation of proliferating MGPCs. We conclude that signaling through BMP4/Smad1/5/8 promotes the formation of MGPCs, whereas signaling through TGFβ/Smad2/3 suppresses the formation of MGPCs.
Results of implementation of a hospital‐based strategy to reduce cesarean delivery among low‐risk women in Canada
Authors: Shoemaker Esther S. , Bourgeault Ivy L. , Cameron Carol , Graham Ian D. , Hutton Eileen K. 
Published: July 2017

AbstractObjectiveTo assess the cesarean delivery (CD) rate among low‐risk pregnancies before and after implementation of a hospital‐based program in Canada.MethodsA prospective before‐and‐after study was conducted to assess the effects of the CARE (CAesarean REduction) strategy, which was developed and implemented at Markham Stouffville Hospital, Toronto, ON, Canada, in 2010 to reduce CD among low‐risk women. Hospital records were reviewed to identify changes in the proportions of CD performed during 12 months (April 2009–March 2010) before implementation of the CARE strategy versus 12 months after implementation (April 2012–March 2013) at Markham Stouffville Hospital and 36 hospitals of the same level in the same province.ResultsAt the intervention hospital, 30.3% (964/3181) of women underwent CD in 2009–2010, compared with 26.4% (803/3045) in 2012–2013 (difference −3.9%, P<0.001). By contrast, no significant difference was recorded in control hospitals (28.1% [23 694/84 361] vs 28.2% [23 683/83 895]; difference 0.1%, P=0.5157).ConclusionImplementation of the CARE strategy reduced rates of CD among the target population.
Targeted therapies in pancreatic cancer: Promises and failures
Authors: Barati Bagherabad Matineh , Afzaljavan Fahimeh , ShahidSales Soodabeh , Hassanian Seyed Mahdi , Avan Amir 
Published: July 2017

AbstractPancreatic ductal adenocarcinoma (PDAC) is an incidence rate nearly equal to its mortality rate. The poor prognosis of the disease can be explained by the absence of effective biomarkers for screening and early detection, together with the aggressive behavior and resistance to the currently available chemotherapy. The therapeutic failure can also be attributed to the inter‐/intratumor genetic heterogeneity and the abundance of tumor stroma that occupies the majority of the tumor mass. Gemcitabine is used in the treatment of PDAC; however, the response rate is less than 12%. A recent phase III trial revealed that the combination of oxaliplatin, irinotecan, fluorouracil, and leucovorin could be an option for the treatment of metastatic PDAC patients with good performance status, although these approaches can result in high toxicity level. Further investigations are required to develop innovative anticancer agents that either improve gemcitabine activity, within novel combinatorial approaches or acts with a better efficacy than gemcitabine. The aim of the current review is to give an overview of preclinical and clinical studies targeting key dysregulated signaling pathways in PDAC.
Identification of sequence polymorphisms in the mitochondrial cytochrome c oxidase genes as risk factors for hepatocellular carcinoma
Authors: Wang Hongfang , Xu Jinsheng , Li Demao , Zhang Shenglei , Guo Zhanjun 
Published: July 2017

BackgroundSingle nucleotide polymorphisms (SNPs) accumulated in the mitochondrial DNA (mtDNA) is susceptible to the tumor formation. We discovered previously that SNPs in the mitochondrial displacement loop (D‐loop) was associated with the risk of hepatocellular carcinoma (HCC).MethodsThe cytochrome c oxidase (COX) genes of mtDNA were sequenced between 107 HCC patients and 100 matched healthy controls. The χ2 test was used to analyze single SNPs’ statistical difference between HCC patients and healthy controls.ResultsIn this study, cancer risk‐associated SNPs in the COX genes of mtDNA coding region were assessed in HCC patients and health controls. The nucleotide position at site 9545A/G (P=.036) was identified its association for HCC with the 9545G allele susceptible to cancer risk.ConclusionsThe SNPs in the COX genes may help us to evaluate the cancer risk of HCC.
Qualitative Research Quality: A Collaborative Inquiry Across Multiple Methodological Perspectives
Authors: Walther Joachim , Sochacka Nicola W. , Benson Lisa C. , Bumbaco Amy E. , Kellam Nadia , Pawley Alice L. , Phillips Canek M. L. 
Published: July 2017

AbstractBackgroundThe field of engineering education research is adopting an increasingly diverse range of qualitative methods. These developments necessitate a coherent language and conceptual framework to critically engage with questions of qualitative research quality.Purpose/HypothesisThis article advances discussions of qualitative research quality through sharing and analyzing a methodologically diverse, practice‐based exploration of research quality in the context of five engineering education research studies.Design/MethodAs a group of seven engineering education researchers, we drew on the collaborative inquiry method to systematically examine questions of qualitative research quality in our everyday research practice. We used a process‐based, theoretical framework for research quality as the anchor for these explorations.ResultsWe constructed five practice explorations spanning grounded theory, interpretative phenomenological analysis, and various forms of narrative inquiry. Examining the individual contributions as a whole yielded four key insights: quality challenges require examination from multiple theoretical lenses; questions of research quality are implicitly infused in research practice; research quality extends beyond the objects, procedures, and products of research to concern the human context and local research setting; and research quality lies at the heart of introducing novices to interpretive research.ConclusionsThis study demonstrates the potential and further need for the engineering education community to advance methodological theory through purposeful and reflective engagement in research practice across the diverse methodological approaches currently being adopted.
Odors generated from the Maillard reaction affect autonomic nervous activity and decrease blood pressure through the olfactory system
Authors: Zhou Lanxi , Ohata Motoko , Owashi Chisato , Nagai Katsuya , Yokoyama Issei , Arihara Keizo 
Published: July 2017

AbstractBACKGROUNDSystolic blood pressure (SBP) of rats decreases significantly following exposure to the odor generated from the Maillard reaction of protein digests with xylose. This study identified active odorants that affect blood pressure and demonstrated the mechanism of action.RESULTSAmong the four potent odorants that contribute most to the odor of the Maillard reaction sample, 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone (DMHF) and 5‐methyl‐2‐pyrazinemethanol (MPM) decreased SBP significantly. The earliest decrease in blood pressure was observed 5 min after exposure to DMHF. Application of zinc sulfate to the nasal cavity eliminated the effect. Furthermore, gastric vagal (parasympathetic) nerve activity was elevated and renal sympathetic nerve activity was lowered after exposure to DMHF.CONCLUSIONIt is indicated that DMHF affects blood pressure through the olfactory system, and the mechanism for the effect of DMHF on blood pressure involves the autonomic nervous system. © 2017 Society of Chemical Industry
Dual energy CT − a possible new method to assess regression of rectal cancers after neoadjuvant treatment
Authors: Al‐Najami Issam , Drue Henrik C. , Steele Robert , Baatrup Gunnar 
Published: July 2017

Background and ObjectivesThe measurement of tumor regression after neoadjuvant oncological treatment has gained increasing interest because it has a prognostic value and because it may influence the method of treatment in rectal cancer. The assessment of tumor regression remains difficult and inaccurate with existing methods. Dual Energy Computed Tomography (DECT) enables qualitative tissue differentiation by simultaneous scanning with different levels of energy. We aimed to assess the feasibility of DECT in quantifying tumor response to neoadjuvant therapy in loco‐advanced rectal cancer.MethodsWe enrolled 11 patients with histological and MRI verified loco‐advanced rectal adenocarcinoma and followed up on them prospectively. All patients had one DECT scanning before neoadjuvant treatment and one 12 weeks after using the spectral imaging scan mode. DECT analyzing tools were used to determine the average quantitative parameters; effective‐Z, water‐ and iodine‐concentration, Dual Energy Index (DEI), and Dual Energy Ratio (DER). These parameters were compared to the regression in the resection specimen as measured by the pathologist.ResultsChanges in the quantitative parameters differed significantly after treatment in comparison with pre‐treatment, and the results were different in patients with different CRT response rates.ConclusionDECT might be helpful in the assessment of rectal cancer regression grade after neoadjuvant treatment.
Analysis of polychlorodibenzo‐p‐dioxins and polychlorodibenzofurans in stationary source emissions in GC–MS/MS using hydrogen as the carrier gas
Authors: Benedetti Paolo , Guerriero Ettore , Mosca Silvia , Rotatori Mauro 
Published: July 2017

AbstractThe European and American methods for the determination of polychlorodibenzo‐p‐dioxins and polychlorodibenzofurans in stationary source emissions require a high‐resolution mass spectrometer detector. At the same time, all of the 17 toxic 2,3,7,8‐chlorine‐substituted isomers have to be separated by an appropriate chromatographic method. The resulting analysis has long runtimes and sometimes a double‐column run is needed, which results in a huge waste of time, money and manual labor. To obtain a fast and cost‐effective but still reliable analytical system, a single‐column gas chromatography with hydrogen as carrier gas and tandem mass spectrometry detection is proposed. The use of hydrogen as the carrier gas is a good choice to shorten runtimes and improve the chromatographic resolution, while tandem mass spectrometry is a well‐known alternative for this analysis. All the chromatographic and mass spectrometric parameters fill the requirements of the reference methods with a 35% reduction of runtimes. The accuracy is tested with three fly ash samples of a proficiency interlaboratory test. A good correlation between the results is obtained (R2 = 0.992, slope = 0.9675), and no coelutions are noted. The system robustness is tested during 5 years of constant use and the maximal relative standard deviation of the relative response factor is 18.8%.
High‐resolution diffusion tensor imaging in cervical spondylotic myelopathy: a preliminary follow‐up study
Authors: Guan Li , Chen Xiaolong , Hai Yong , Ma Xiaodong , He Le , Wang Guangzhi , Yuan Chun , Guo Hua 
Published: July 2017

Diffusion imaging is a promising technique as it can provide microstructural tissue information and thus potentially show viable changes in spinal cord. However, the traditional single‐shot imaging method is limited as a result of various image artifacts. In order to improve measurement accuracy, we used a newly developed, multi‐shot, high‐resolution, diffusion tensor imaging (DTI) method to investigate diffusion metric changes and compare them with T2‐weighted (T2W) images before and after decompressive surgery for cervical spondylotic myelopathy (CSM). T2W imaging, single‐shot DTI and multi‐shot DTI were employed to scan seven patients with CSM before and 3 months after decompressive surgery. High signal intensities were scored using the T2 W images. DTI metrics, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD), were quantified and compared pre‐ and post‐surgery. In addition, the relationship between imaging metrics and neurological assessments was examined. The reproducibility of multi‐shot DTI was also assessed in 10 healthy volunteers. Post‐surgery, the mean grade of cervical canal stenosis was reduced from grade 3 to normal after 3 months. Compared with single‐shot DTI, multi‐shot DTI provided better images with lower artifact levels, especially following surgery, as a result of reduced artifacts from metal implants. The new method also showed acceptable reproducibility. Both FA and RD values from the new acquisition showed significant differences post‐surgery (FA, p = 0.026; RD, p = 0.048). These changes were consistent with neurological assessments. In contrast, T2W images did not show significant changes before and after surgery. Multi‐shot diffusion imaging showed improved image quality over single‐shot DWI, and presented superior performance in diagnosis and recovery monitoring for patients with CSM compared with T2W imaging. DTI metrics can reflect the pathological conditions of spondylotic spinal cord quantitatively and may serve as a sensitive biomarker for potential CSM management.
Model reduction from partial observations
Authors: Herzet C. , Héas P. , Drémeau A. 
Published: July 2017

SummaryThis paper deals with model‐order reduction of parametric partial differential equations (PPDEs). More specifically, we consider the problem of finding a good approximation subspace of the solution manifold of the PPDE when only partial information on the latter is available. We assume that 2 sources of information are available: (a) a “rough” prior knowledge taking the form of a manifold containing the target solution manifold and (b) partial linear measurements of the solutions of the PPDE (the term partial refers to the fact that observation operators cannot be inverted). We provide and study several tools to derive good approximation subspaces from these 2 sources of information. We first identify the best worst‐case performance achievable in this setup and propose simple procedures to approximate the corresponding optimal approximation subspace. We then provide, in a simplified setup, a theoretical analysis relating the achievable reduction performance to the choice of the observation operator and the prior knowledge available on the solution manifold.
QM/MM calculations combined with the dimer approach on the static disorder at organic‐organic interfaces of thin‐film organic solar cells composed of small molecules
Authors: Brückner Charlotte , Stolte Matthias , Würthner Frank , Pflaum Jens , Engels Bernd 
Published: July 2017

AbstractA QM/MM approach using ωB97X‐D combined with AMOEBA calculations was used to analyze the energetic disorder in the vicinity of interfaces in amorphous organic heterostructures. Distributions of ground‐, excited‐, and cationic‐state energies as well as of ionization potentials and excitation energies, all being relevant quantities for the transport properties of thin films, were calculated. As already found for bulk amorphous organic semiconductors, local densities of states at molecular interfaces possess Gaussian‐shaped profiles with a significant amount of disorder. Assuming a disorder‐limited activation of exciton and charge transport, a decrease in the amount of disorder could improve the transport properties. Relating calculated disorders to molecular parameters revealed that in line with the Bässler model, especially the molecular polarity, its change upon electronic excitation, and the molecular polarizability are relevant quantities leading to energetically largely disordered films. Moreover, because of the different mechanisms of exciton and polaron delocalization, a given morphology with disordered charge‐transport levels gives not necessarily rise to disordered exciton‐transport levels and vice versa.