bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tolerance design of patient‐specific range QA using the DMAIC framework in proton therapy
Authors: Rah Jeong‐Eun , Shin Dongho , Manger Ryan P. , Kim Tae Hyun , Oh Do Hoon , Kim Dae Yong , Kim Gwe‐Ya 
Published: December 2017

PurposeTo implement the DMAIC (Define‐Measure‐Analyze‐Improve‐Control) can be used for customizing the patient‐specific QA by designing site‐specific range tolerances.MethodsThe DMAIC framework (process flow diagram, cause and effect, Pareto chart, control chart, and capability analysis) were utilized to determine the steps that need focus for improving the patient‐specific QA. The patient‐specific range QA plans were selected according to seven treatment site groups, a total of 1437 cases. The process capability index, Cpm was used to guide the tolerance design of patient site‐specific range.ResultsFor prostate field, our results suggested that the patient range measurements were capable at the current tolerance level of ±1 mm in clinical proton plans. For other site‐specific ranges, we analyzed that the tolerance tends to be overdesigned to insufficient process capability calculated by the patient‐specific QA data. The customized tolerances were calculated for treatment sites. Control charts were constructed to simulate the patient QA time before and after the new tolerances were implemented. It is found that the total simulation QA time was decreased on average of approximately 20% after establishing new site‐specific range tolerances. We simulated the financial impact of this project. The QA failure for whole process in proton therapy would lead up to approximately 30% increase in total cost.ConclusionDMAIC framework can be used to provide an effective QA by setting customized tolerances. When tolerance design is customized, the quality is reasonably balanced with time and cost demands.
Development of depth encoding small animal PET detectors using dual‐ended readout of pixelated scintillator arrays with SiPMs
Authors: Kuang Zhonghua , Sang Ziru , Wang Xiaohui , Fu Xin , Ren Ning , Zhang Xianming , Zheng Yunfei , Yang Qian , Hu Zhanli , Du Junwei , Liang Dong , Liu Xin , Zheng Hairong , Yang Yongfeng 
Published: December 2017

PurposeThe performance of current small animal PET scanners is mainly limited by the detector performance and depth encoding detectors are required to develop PET scanner to simultaneously achieve high spatial resolution and high sensitivity. Among all depth encoding PET detector approaches, dual‐ended readout detector has the advantage to achieve the highest depth of interaction (DOI) resolution and spatial resolution. Silicon photomultiplier (SiPM) is believed to be the photodetector of the future for PET detector due to its excellent properties as compared to the traditional photodetectors such as photomultiplier tube (PMT) and avalanche photodiode (APD). The purpose of this work is to develop high resolution depth encoding small animal PET detector using dual‐ended readout of finely pixelated scintillator arrays with SiPMs.MethodsFour lutetium‐yttrium oxyorthosilicate (LYSO) arrays with 11 × 11 crystals and 11.6 × 11.6 × 20 mm3 outside dimension were made using ESR, Toray and BaSO4 reflectors. The LYSO arrays were read out with Hamamatsu 4 × 4 SiPM arrays from both ends. The SiPM array has a pixel size of 3 × 3 mm2, 0.2 mm gap in between the pixels and a total active area of 12.6 × 12.6 mm2. The flood histograms, DOI resolution, energy resolution and timing resolution of the four detector modules were measured and compared.ResultsAll crystals can be clearly resolved from the measured flood histograms of all four arrays. The BaSO4 arrays provide the best and the ESR array provides the worst flood histograms. The DOI resolution obtained from the DOI profiles of the individual crystals of the four array is from 2.1 to 2.35 mm for events with E > 350 keV. The DOI ratio variation among crystals is bigger for the BaSO4 arrays as compared to both the ESR and Toray arrays. The BaSO4 arrays provide worse detector based DOI resolution. The photopeak amplitude of the Toray array had the maximum change with depth, it provides the worst energy resolution of 21.3%. The photopeak amplitude of the BaSO4 array with 80 μm reflector almost doesn't change with depth, it provides the best energy resolution of 12.9%. A maximum timing shift of 1.37 ns to 1.61 ns among the corner and the center crystals in the four arrays was obtained due to the use of resistor network readout. A crystal based timing resolution of 0.68 ns to 0.83 ns and a detector based timing resolution of 1.26 ns to 1.45 ns were obtained for the four detector modules.ConclusionsFour high resolution depth encoding small animal PET detectors were developed using dual‐ended readout of pixelated scintillator arrays with SiPMs. The performance results show that those detectors can be used to build a small animal PET scanner to simultaneously achieve uniform high spatial resolution and high sensitivity.
Distortion of KB estimates of endothelin‐1 ETA and ETB receptor antagonists in pulmonary arteries: Possible role of an endothelin‐1 clearance mechanism
Authors: Angus James A. , Hughes Richard J. A. , Wright Christine E. 
Published: December 2017

AbstractDual endothelin ETA and ETB receptor antagonists are approved therapy for pulmonary artery hypertension (PAH). We hypothesized that ETB receptor‐mediated clearance of endothelin‐1 at specific vascular sites may compromise this targeted therapy. Concentration‐response curves (CRC) to endothelin‐1 or the ETB agonist sarafotoxin S6c were constructed, with endothelin receptor antagonists, in various rat and mouse isolated arteries using wire myography or in rat isolated trachea. In rat small mesenteric arteries, bosentan displaced endothelin‐1 CRC competitively indicative of ETA receptor antagonism. In rat small pulmonary arteries, bosentan 10 μmol L−1 left‐shifted the endothelin‐1 CRC, demonstrating potentiation consistent with antagonism of an ETB receptor‐mediated endothelin‐1 clearance mechanism. Removal of endothelium or L‐NAME did not alter the EC50 or Emax of endothelin‐1 nor increase the antagonism by BQ788. In the presence of BQ788 and L‐NAME, bosentan displayed ETA receptor antagonism. In rat trachea (ETB), bosentan was a competitive ETB antagonist against endothelin‐1 or sarafotoxin S6c. Modeling showed the importance of dual receptor antagonism where the potency ratio of ETA to ETB antagonism is close to unity. In conclusion, the rat pulmonary artery is an example of a special vascular bed where the resistance to antagonism of endothelin‐1 constriction by ET dual antagonists, such as bosentan or the ETB antagonist BQ788, is possibly due to the competition of potentiation of endothelin‐1 by blockade of ETB‐mediated endothelin‐1 clearance located on smooth muscle and antagonism of ETA‐ and ETB‐mediated contraction. This conclusion may have direct application for the efficacy of endothelin‐1 antagonists for treating PAH.
Application of ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry in identification of three isoflavone glycosides and their corresponding metabolites
Authors: Xu Xiafen , Li Xinhui , Liang Xianrui 
Published: December 2017

RationaleMetabolites of isoflavones have attracted much attention in recent years due to their potential bioactivities. However, the complex constituents of the metabolic system and the low level of metabolites make them difficult to analyze. A mass spectrometry (MS) method was applied in our identification of metabolites and study of their fragmentation pathways due to the advantages of rapidity, sensitivity, and low level of sample consumption.MethodsThree isoflavone glycosides and their metabolites were identified using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry (UPLC/QTOF‐MS). These metabolites were obtained by anaerobically incubating three isoflavone glycosides with human intestinal flora. The characteristic fragments of isoflavone glycosides and their metabolites were used for the identification work.ResultsTwo metabolites from ononin, three metabolites from irilone‐4′‐O‐β‐D‐glucoside, and five metabolites from sissotrin were identified respectively by the retention time (RT), accurate mass, and mass spectral fragmentation patterns. The losses of the glucosyl group, CO from the [M+H]+ ion were observed for all the three isoflavone glycosides. The characteristic retro‐Diels‐Alder (RDA) fragmentation patterns were used to differentiate the compounds. The metabolic pathways of the three isoflavone glycosides were proposed according to the identified chemical structures of the metabolites.ConclusionsA selective, sensitive and rapid method was established for detecting and identifying three isoflavone glycosides and their metabolites using UPLC/QTOF‐MS. The established method can be used for further rapid structural identification studies of metabolites and natural products. Furthermore, the proposed metabolic pathways will be helpful for understanding the in vivo metabolic process of isoflavone.
An Efficient Ecofriendly Enantioselective Organocatalytic Ring‐Closing Reaction of 2‐Hydroxychalcone via Intramolecular Oxa‐Michael Reaction
Authors: Singh Ashawani Kumar , Mangawa Shrawan Kumar , Kumar Arvind , Dixit A. K. , Awasthi Satish Kumar 
Published: December 2017

AbstractAn organocatalyzed highly asymmetric cascade oxa‐Michael addition reaction for the synthesis of flavanone from 2‐hydroxychalcone has been developed. This method works well with low catalyst loading and has broad range substrate scope, furnishing the desired product in excellent yield and displays an intrinsic enantioselectivity of upto 99.9 % ee. This method provides a straightforward entry into highly functionalized chiral flavanone derivatives.
Syntheses, Crystal Structures and Spectroscopic Studies of Bis[1‐methyl‐3‐(methoxycarbonylmethyl)‐benzimidazolium]2+ [CuBr4]2− and [ZnBr4]2− Compounds
Authors: Czekański Łukasz , Hoffmann Stanisław K. , Barczyński Piotr , Gąsowska A. , Zalewska Alina , Goslar Janina , Ratajczak‐Sitarz Małgorzata , Katrusiak Andrzej 
Published: December 2017

AbstractX‐ray diffraction structure of two new bis [1‐methyl‐3‐(methoxycarbonylmethyl) benzimidazolium]2+ [CuBr4]2− and [ZnBr4]2− compounds has been determined. Zn‐crystal is monoclinic with perfect Td symmetry of the ZnBr4 tetrahedron, whereas the Cu‐compound is orthorhombic with D2d symmetry of CuBr4 tetrahedron. The difference in these structures is described as due to the static Jahn‐Teller effect. Vibrational spectroscopy (1800–3200 cm−1) identified hydrogen bond network. NIR‐UV‐Vis spectra (5000–50000 cm−1) are dominated by ligand‐to‐metal bands with d‐d transition contribution. EPR results (Q‐band) analyzed in terms of the MO‐theory showed a very strong delocalization of unpaired electron density on ligands accompanied by the Cu(II) 4pz orbital contribution. This effect is partially compensated by charge transfer transitions to the EPR g‐factor.
Hydrogen Generation via Activation of X‐H Bonds in Ammonia and Water by an MoI Complex
Authors: Bandeira Nuno A. G. , Veiros Luís F. , Bo Carles 
Published: December 2017

AbstractThe mechanism of H2 production from a Mo(I) complex with terpyridine and phosphine ancillary ligands, [Mo(NH3)(Phtbpy)(PPh2Me)2]+ was computationally investigated by DFT calculations. Several tentative pathways were tested and the most favourable one corresponds to a bimolecular mechanism that starts with the oxidative addition of the N−H bond in NH3, yielding a 7‐coordinate Mo(III) species with a hydride and an amido ligand. In a second step two such intermediates join to form H2 and the Mo(II) co‐product, [Mo(NH2)(Phtbpy)(PPh2Me)2]+. The first step has the highest barrier and its value (26.5 kcal/mol) is in agreement with mild reaction conditions, as experimentally observed (6 hours at 60 °C). The entire process occurs with spin change from S=
in the initial complex to S=0 in the products. The same mechanism is also operative using water and methanol as ligands, the corresponding free energy barrier being ca. 7 kcal/mol lower than the one calculated for NH3.
Deeply Repairing Surface States with Wet Chemistry Methods: Enhanced Performance in TiO2 Nanowire Arrays‐Based Optoelectronic Device
Authors: Zha Chenyang , Zhang Jun‐Jie , Shen Liming , Dong Shuai , Gupta Arunava , Bao Ningzhong 
Published: December 2017

AbstractOne‐dimensional (1D) single‐crystalline rutile TiO2 nanowire arrays (TiO2 NWAs) have generally been considered superior over TiO2 nanoparticle films for the optoelectronic applications. We discovered that the conventional oxygen annealing method cannot efficiently repair the surface trap states of the TiO2 NWAs that significantly influence the charge diffusion. In this work, we demonstrate a highly effective wet chemistry method to repair the surface states by the successive ionic layer adsorption and reaction (SILAR). The density functional calculations (DFT)‐based simulation has been used to explain the physical mechanism of reparation of the surface oxygen vacancies of by CdS or PbS quantum dots (QDs). The analysis results of photoluminescence spectroscopy (PL) and electrochemical analysis conformed the enhanced optoelectronic conversion efficiency. A 20–30% improvement in solar cell performance has been obtained over the PbS or CdS QDs coated dye‐sensitized solar cells. The SILAR method for deeply repairing the surface trap states can be extended to the systhesis of other semiconducting nanocrystals and its solar energy conversion applications.
The Ritter Reaction of 2‐Oxoaldehydes at Room Temperature: Divergent Behaviour towards Acid Strength.
Authors: Khan Shahnawaz , Kumar Atul , Gupta Raman , Ahmed Qazi N. 
Published: December 2017

AbstractAn efficient, novel, atom economical and selective amidation method for the generation of mono and di‐Ritter products using 2‐oxoaldehydes under acidic environment at room temperature was successfully developed. The di‐Ritter products obtained are accessed in good yields when stirred in the presence of 20 mol % H2SO4, and the mono products were selectively obtained in moderate yields with CuOTf as catalyst. However, the yields of the latter were optimized by the addition of SeO2.
Ln8 (Ln= Gd, Ho, Er, Yb) Butterfly Core‐Exhibiting Magnetocaloric Effect and Field‐Induced SMM Behavior for Er Analouge
Authors: Bala Sukhen , Adhikary Amit , Bhattacharya Sudeshna , Bishwas Mousumi Sen , Poddar Pankaj , Mondal Raju 
Published: December 2017

AbstractIn this article, we report four pyridyl‐pyrazolyl based polynuclear cluster complexes with Ln8 {Ln=[GdIII8(μ3‐OH)4(L1)4(DEA)4Cl4](DMF)2(MeOH)(1), [HoIII8(μ3‐OH)4(L1)4(DEA)4Cl4](2), [ErIII8(μ3‐OH)4(L1)4(DEA)4Cl4](DMF)(MeOH)(H2O)(3), [YbIII8(μ3‐OH)4(L1)4(DEA)4Cl4](DMF)(MeOH)(4) [DEA = Diethanolamine] cores. The impetus for this study was to explore the magnetic behaviour of lanthanide ions which are often ignored or overlooked. X‐ray crystal analysis show that these complexes are isostructural and exhibit an interesting butterfly like topology. The semi‐rigidity and asymmetric nature of the ligand led to different coordination environment around the metal centres. The lanthanide ions adopt two types of geometry, a bicapped trigonal prism and a distorted square antiprismatic geometry around the metal center. Such dissimilar coordination environments around the lanthanide centre can have profound effects on their magnetic behaviour. Indeed, the magnetic measurements revealed significant magnetocaloric effect for octanuclear gadolinium complex 1 with magnetic entropy change (−ΔSm ) of 31.4 J kg−1 K−1 for ΔH = 9 T at T = 3 K whereas Er analogue complex 3 displayed SMM behavior.
A Categorical Naked‐Eye Detection of Cu2+ and Zn2+ through a Donor‐Acceptor‐Donor (D‐A‐D)‐Type Salicylaldimine: An Experimental and Theoretical Approach
Authors: Kumar Virendra , Diwan Uzra , Sanskriti Isha , Mishra Rakesh K. , Upadhyay K. K. 
Published: December 2017

AbstractA Schiff base viz., 2,3‐bis‐(3, 5‐di‐tert‐butyl‐2‐hydroxybenzylidene) amino maleonitrile (TBCN), having donor–acceptor–donor (D–A–D) type constitution exhibited Cu2+ and Zn2+ guided specific modulations in its ICT (intramolecular charge transfer) characteristics. The corresponding naked eye changes for Cu2+ and Zn2+ involved the shifting of characteristic ICT band of TBCN at ∼472 nm (yellow) to ∼ 566 nm (pink) and ∼590 nm (indigo blue) respectively in a semi‐aqueous medium (EtOH:H2O in a ratio of 8:2 v/v). The TBCN as well as its ensembles with Cu2+ and Zn2+ were fully characterized through their single crystal XRD studies along with spectroscopic and mass spectral studies. The DFT and the time‐dependent DFT calculations provided a genuine rationale for separate naked eye colorimetric changes of TBCN for Cu2+ and Zn2+.
Strategies to Produce Chlorinated Indole‐3‐Acetic Acid and Indole‐3‐Acetic Acid Intermediates
Authors: Patallo Eugenio P. , Walter Antje , Milbredt Daniela , Thomas Marion , Neumann Madeleine , Caputi Lorenzo , O'Connor Sarah , Ludwig‐Müller Jutta , van Pée Karl‐Heinz 
Published: December 2017

AbstractTryptophan and indole derivatives are common precursors in many natural biosynthetic pathways. In recent years it has been shown that the substrate specificity of tryptophan halogenases is much more relaxed than previously thought. Using the tryptophan 7‐halogenase PrnA, the tryptophan 6‐halogenase ThdH, and the tryptophan 5‐halogenase PyrH we achieved the regioselective mono‐halogenation of indole‐3‐acetic acid (IAA), which has not been reported as a substrate of tryptophan halogenases to date. The tryptophan 5‐halogenase gene was introduced into Arabidopsis thaliana leading to the formation of 5‐chlorotryptophan, 5‐chloroindole‐3‐acetonitrile and 5‐chloro‐3‐indole acetic acid by A. thaliana. PyrH activity could also be demonstrated for the plant‐produced halogenase in vitro. These results show the potential of flavin‐dependent halogenases to generate novel halogenated auxins or other secondary metabolites in vitro and in vivo by plants.
Syntheses, Crystal Structures and Photophysical Aspects of Discrete and Polymeric Azido‐Bridged Zinc(II) and Cadmium(II) Complexes: Sensing Properties and Structural Resemblance
Authors: Roy Shuvayan , Bhattacharya Sagarika , Mohanta Sasankasekhar 
Published: December 2017

AbstractThe work in this report presents syntheses, characterization, crystal structures and steady state and time resolved photophysical properties of four compounds of composition [ZnII3L12(N3)4] (1), [CdII3L22(N3)4]n (2), [ZnII2L2(N3)3]n (3) and [CdII2L1(N3)3]n (4), where HL1 and HL2 are the Schiff base ligands, obtained on 1:1 condensation of 3‐ethoxysalicylaldehyde (for HL1)/3‐methoxysalicylaldehyde (for HL2) and N,N,2,2‐tetramethyl‐1,3‐propanediamine. Compound 1 is a discrete trizinc(II) system, while the other three compounds are one‐dimensional coordination polymers, where the building units are, respectively, tricadmium(II), dizinc(II) and dicadmium(II) moieties. The nuclearities of the cores in the ZnII–azido compound from HL1 and the CdII–azido compound from HL2 are similar (1 and 2 are trinuclear) and, similarly, the ZnII–azido compound from HL2 and the CdII–azido compound from HL1 are similar (3 and 4 are dinuclear), revealing an unusual structural resemblance of two metal ions of two different rows in the periodic table as the function of slight change in the ligand periphery (OEt in HL1, OMe in HL2). The steady state/time‐resolved photophysical properties reveal that cadmium(II) enhances slightly but zinc(II) enhances appreciably the fluorescence of the Schiff base ligands HL1 and HL2. It has been found that both HL1 and HL2 are fluorogenic sensors of zinc(II).
Graphitic Carbon Nitride (g‐C3N4)‐derived Fe‐N‐C Catalysts for Selective Hydrodeoxygenation of 5‐Hydroxymethylfurfural to 2,5‐Dimethylfuran
Authors: Li Jiang , Zhang Jun‐jie , Liu He‐yang , Liu Jun‐ling , Xu Guang‐yue , Liu Jia‐xing , Sun Hui , Fu Yao 
Published: December 2017

AbstractAs Fe is more abundant and economic than Cu and Ni, it is probably a more attractive non‐noble alternative to precious metals in biomass conversions, for which usually require promising catalysts for large‐scale production. In this work, economic and environmental benign heterogeneous iron catalysts prepared by simultaneous pyrolysis of graphitic carbon nitride and iron precursors on activated carbon, were demonstrated to be active for the hydrodeoxygenation of biomass‐derived 5‐hydroxymethylfurfural to 2,5‐dimethylfuran. The effect of pyrolysis temperature, support, iron content, the type of g‐C3N4 and iron precursor, and N/Fe ratio were explored thoroughly, and reaction parameters such reaction temperature and H2 pressure were also investigated. The highest DMF yield of 85.7 % was obtained at 240 °C for 3 h, which is comparable to that obtained over iron catalysts prepared from precious iron complexes. The investigation of reaction pathway showed that 5‐methylfurfural was the possible intermediate. The stability of as‐prepared Fe‐N‐C catalyst could be improved after treatment with aqueous HCl solution.
Novel Benzimidazole‐Containing Heterocyclic Compounds: Synthesis, Physical Properties and OLED Application
Authors: Shen Yuqiang , Li Junbo , Chen Shao , Wan Jiaqi , Zhao Yongbiao , Lu Zheng‐Hong , Li Miao , Yang Li , Yu Xianglin , Chen Dugang , Pan Zhiquan 
Published: December 2017

AbstractThree novel heterocyclic compounds containing one (M1) or two (isomers M2 and M3) benzimidazole units have been synthesized and fully characterized. The isomers M2 and M3 could be easily separated by column chromatography. Studies showed that the decrease of intermolecular π‐π stackings could enhance the fluorescence intensity of target compounds obviously. The single‐site compound M1 shows the lowest fluorescent quantum yield (ΦM1=0.013) in CH2Cl2 than that of the double‐site isomers M2 (anti‐type, ΦM2=0.148) and M3 (syn‐type, ΦM3=0.053). Electroluminescent performances of M2 and M3 in organic light‐emitting diodes were studied. As expected, M2 exhibits more than 2 times higher current efficiency than M3 with M2 showing a maximum current efficiency of 7.8 cd/A as compare to 3.6 cd/A for M3.
Fluorine‐Substituted Ligands Induce Structural Diversity of Coordination Compounds
Authors: Khavasi Hamid Reza , Rahimi Narjes 
Published: December 2017

AbstractSeven inorganic coordination compounds based on HgBr2 and Ln−F ligands, in which Ln−F are N‐(fluorinated phenyl)‐2‐pyrazinecarboxamide, bearing fluorine substituent in different position on phenyl ring have been synthesized. These complexes, [HgBr2(L2−F)2]n, 1, [HgBr2L3−F]n, 2, [HgBr2L4−F]n, 3, [HgBr2L2,5−F]n, 4, [HgBr2(L2,6−F)2], 5, [HgBr2L2,3,4−F], 6, and [HgBr2L2,3,4,5−F]n, 7, are characterized in order to get precise insight into the fluorine substituent effect on the coordination structures. The crystal structure data resulting from X‐ray diffraction reveal that, in spite of the same metal, counter ion and reaction conditions, overall structural diversity is evident in all cases. Accordingly, fluorinated ligand exercise influence on not only first coordination sphere but also supramolecular architecture and overall construction. As a matter of fact, small changes in the position and number of fluorine existed on the phenyl ring direct both first and second coordination sphere around metal ion.