bluuebunny/crossref_metadata_2025 huggingface dataset:
Changing outcomes and treatment strategies for wire induced coronary perforations in the era of bivalirudin use
Authors: Kini Annapoorna S. , Rafael Oana C. , Sarkar Kunal , Rajdev Sanjay , Jakkula Madhavi , Mares Angelica M. , Kaplish Dheeraj , Krishnan Prakash , Kim Michael C. , Sharma Samin K.
Published: May 2009

Objectives: The objective of this study is to analyze the clinical outcomes and treatment strategies of coronary wire perforations (WPs) in the era of heparin use compared to the era of bivalirudin use. Background: Percutaneous coronary intervention (PCI) advances have led to progressive decrease in complications. Therefore, complex coronary lesions such as chronic total occlusions and calcified lesions are being attempted with stiff/hydrophilic wires with resultant higher incidence of coronary WP. Methods: A single‐center retrospective data analysis of coronary perforation (CP) for the last 4 years with review of coronary angiograms was done and WPs were identified. A simple classification scheme based on angiographic appearance of CP was made: Type I (“myocardial stain,” with no frank dye extravasation) and type II (“myocardial fan,” with dye extravasation to pericardial cavity or cardiac chambers). Results: Overall incidence of CP was 0.49% (82/16,859). Of these 50 (61%) were caused by WP; 30 occurred with heparin use (Group A) and 20 with bivalirudin use (Group B). WPs always occurred in type B2/C lesions (100%) and commonly with use of hydrophilic guidewires (70%). Major adverse cardiac events and cardiac tamponade were frequent in group A (50%) and none in group B (0%); P < 0.01. All WP in group B responded to stopping anticoagulation and prolonged balloon inflation, while group A type II perforations frequently required additional interventions (pericardiocentesis, coil embolization). Conclusions: Cardiac tamponade and major adverse cardiac events from WPs were less frequent with bivalirudin use compared to heparin use. This beneficial effect of bivalirudin may be explained on the basis of its short half‐life and reversible thrombin inhibition property. Therefore, bivalirudin may offer a safer alternative for anticoagulation in complex PCI. © 2009 Wiley‐Liss, Inc.
Decomposition of Organic Compounds in Water by Direct High Voltage Discharge
Authors: Yang H. , Zhang X. , Wen S. , Yuan W.
Published: May 2009

Degradation of phenol in water using direct high voltage discharge was investigated. The effects of some factors, including the pressure of the oxygen input, oxygen flow rate, ground electrode diameter, and initial pH were studied on the removal rate of phenol. Higher oxygen pressure and alkaline circumstance improved the process of decomposition. Under the condition of ground electrode inner diameter of 29 mm, oxygen flow rate of 60 mL/min, the removal rate reached 90 % after 180‐min discharge treatment. The solution conductivity was found to change with the removal rate of phenol accordingly.
Second‐Order Nonlinear Optical Activity of Dipolar Chromophores Based on Pyrrole‐Hydrazono Donor Moieties
Authors: Abbotto Alessandro , Beverina Luca , Manfredi Norberto , Pagani Giorgio A. , Archetti Graziano , Kuball Hans‐Georg , Wittenburg Christian , Heck Jürgen , Holtmann Jan
Published: May 2009

Donor1+donor2→acceptor: The second‐order NLO molecular properties of a class of dipolar chromophores that incorporate the following design elements are investigated: 1) a substituted hydrazono moiety as a strong donor; 2) a pyrrole ring as an auxiliary donor; 3) strong acceptor groups (see figure). Their first hyperpolarisabilities show good promise for use in electro‐optical devices.

magnified image

A series of highly efficient and thermally stable second‐order nonlinear optical (NLO) dipolar donor–auxiliary donor–acceptor chromophores have been synthesised in which a hydrazono group and a pyrrole ring act as donor and auxiliary donor components, respectively, in combination with different aromatic and heteroaromatic acceptors. The new dyes have been systematically investigated by NMR spectroscopy, absorption spectroscopy, NLO measurements and thermal stability studies. NLO properties have been studied in detail by electro‐optical absorption (EOA) and hyper‐Rayleigh scattering (HRS) measurements in 1,4‐dioxane and DMSO, respectively. The results originating from the two different methods have been compared and analysed in detail. We found that the NLO properties measured by the EOA and HRS methods correlate with each other and converge to reveal the dye with the acceptor 2‐dicyanomethylene‐3‐cyano‐4,5,5‐trimethyl‐2,5‐dihydrofuran as the most efficient system. The unprecedented combination of a strong donor hydrazono group and the auxiliary donor effects of π‐excessive heteroaromatic rings afforded NLO chromophores with very high values (μgβ0(EOA) up to 2038×10−48 esu and β(HRS) up to 3980×10−30 esu at 1.5 μm).
Hydrogen‐Bonding‐Mediated Dynamic Covalent Synthesis of Macrocycles and Capsules: New Receptors for Aliphatic Ammonium Ions and the Formation of Pseudo[3]rotaxanes
Authors: Xu Xiao‐Na , Wang Lu , Wang Gui‐Tao , Lin Jian‐Bin , Li Guang‐Yu , Jiang Xi‐Kui , Li Zhan‐Ting
Published: May 2009

Dynamic covalent synthesis! Intramolecular hydrogen‐bonding induces amino‐ and aldehyde‐appended aryl amides to adopt a rigid “V”‐shaped conformation. As a result, stable two‐layered capsules can be assembled quantitatively through the one‐step formation of six imine bonds. The new capsules form complexes with aliphatic diammonium ions to give unique two‐layered pseudo[3]rotaxanes (see figure).

magnified image

This paper describes a novel, highly efficient approach to the self‐assembly of monomacrocycles and two‐layered capsules by using dynamic covalent chemistry. Intramolecular hydrogen‐bonding was used to preorganize aromatic amide‐based monomers that contain aldehyde and tert‐butoxycarbonylamino units. As a result, in the presence of an excess of trifluoroacetic acid (TFA), four monomers could self‐couple to produce macrocycles selectively through the formation of three imine or hydrazone bonds. Three dipodal precursors were also prepared by connecting two hydrogen‐bonded segments with a flexible linker. In the presence of TFA, these precursors could also self‐couple, leading to the exclusive formation of two‐layered capsules. As a result of intramolecular hydrogen‐bonding, all the macrocycles and capsules were stable in solution and could be purified by simple recrystallization. The new capsules were able to form complexes with linear propylenediammonium derivatives to give unique two‐layered pseudo[3]rotaxanes.
Evaluation and Comparison of a 3,5‐Dimethylphenyl Isocyanate Teicoplanin and Phenyl Isocyanate Teicoplanin Chiral Stationary Phases
Authors: SHEN Baochun , ZHANG Datong , YUAN Jianyong , XU Beijia , XU Xiuzhu
Published: May 2009

Two chiral stationary phases (CSP), phenyl isocyanate teicoplanin CSP (Ph‐TE) and 3,5‐dimethylphenyl isocyanate teicoplanin CSP (DMP‐TE) were prepared from the macrocyclic glycopeptide teicoplanin CSP (TE) using derivative agents, phenyl isocyanate or 3,5‐dimethylphenyl isocyanate, respectively. The evaluation and comparison of these two self‐made CSP were conducted using HPLC enantiomeric separations in two different mobile phase modes, i.e., the reversed phased (RP) mode and the polar organic (PO) mode. The chromatographic results were given as the retention, selectivity, and resolution factors. Twelve racemic analytes, including eight amino acids and four non‐amino acid compounds, amino‐(4‐hydroxyphenyl) acetic acid, 4‐(1‐hydroxyethyl)‐2‐methoxy phenol, lamivudine and oxazepam reached enantioseparation using the RPLC mobile phase on these two new CSP. The results show that the retention factors and stereoselectivity factors on DMP‐TE are somewhat bigger than those on Ph‐TE for most analytes in the RPLC mobile phase. Six amino alcohols reached enantiomeric separation on these two CSP using the PO mobile phase. The retention of these amino alcohols on DMP‐TE is longer than that on Ph‐TE but the selectivities have little difference between these two CSP. Comparison of the enantiomeric separations using self‐made Ph‐TE and DMP‐TE were conducted in order to gain a better understanding of the chiral recognition mechanism of the macrocyclic glycopeptide CSP.
Electrochemical Impedance Spectroscopic Measurements of Sexithiophene–Effect of the Electrode Nature and the Dopant (CuCl2) Content
Authors: NESSARK Belkacem , MAOUCHE Naïma
Published: May 2009

Electrochemical impedance spectroscopic (EIS) measurements of sexithiophene (6T) were carried out according to the Pt/6T/M sandwich structure configuration, for various electrode materials (M=GC, ITO, Ag, Cu, Al) and for different doping levels of copper chloride (CuCl2). The results demonstrate that two types of charge transport are involved in the redox process at the electrode/6T interface and inside the bulk oligomer. The complex‐plane impedance plots obtained for various doping levels of CuCl2 exhibit arc shapes. The charge‐transfer resistance measured from the diagrams decreases systematically with the addition of the salt, leading to an increase of the oligothiophene conductivity.
Non‐isothermal Decomposition Kinetics, Specific Heat Capacity and Adiabatic Time‐to‐explosion of 1‐Amino‐1‐hydrazino‐2,2‐dinitroethylene (AHDNE)
Authors: XU Kangzhen , ZHAO Fengqi , SONG Jirong , CHANG Chunran , LI Meng , WANG Yaoyu , HU Rongzu
Published: May 2009

The thermal behavior and non‐isothermal kinetics of the exothermic decomposition reaction of 1‐amino‐1‐hydrazino‐2,2‐dinitroethylene (AHDNE) were studied with DSC and TG/DTG methods. The kinetic equation obtained is dα/dT=1019.29(1−α)exp(−1.88×104/T)/β. The critical temperature of thermal explosion is 98.16 °C. The specific heat capacity of AHDNE was determined, and the standard molar specific heat capacity is 211.86 J·mol−1·K−1 at 298.15 K. The adiabatic time‐to‐explosion of AHDNE was also calculated to be 59.21 s. AHDNE is unstable and has much lower thermostability than 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7).
Calorimetric Study and Thermal Analysis of 4‐(Aminomethyl) Benzoic Acid
Authors: ZHENG Qingyun , TAN Zhicheng , WANG Difan , HAO Aiping , LIU Beiping , LÜ Xuechuan , SHI Quan
Published: May 2009

Molar heat capacities of 4‐(aminomethyl)benzoic acid were precisely measured with a small sample precision automated adiabatic calorimeter over the temperature range from 80 to 400 K, and the heat capacity data were fitted to a polynomial equation:Cp,m=162.01+91.771X+6.4372X2+1.7517X3−4.991X4+8.909X5+1.585X6,X= (T−235)/155. The constant‐volume energy of combustion of the compound was measured by means of a precision oxygen bomb combustion calorimeter. The standard enthalpy values of combustion and formation were determined to be: ΔcHm⊖= − (4300±4) kJ·mol−1and ΔfHm⊖= −(420±5) kJ·mol−1.
Molal Enthalpy of Solution of Ionic Liquid [C2mim][GaCl4]
Authors: GUAN Wei , LIU Li , WANG Caixia , YANG Jiazhen
Published: May 2009

An ionic liquid (IL), [C2mim][GaCl4] (1‐ethyl‐3‐methylimidazolium chlorogallate), was prepared by directly mixing 1‐ethyl‐3‐methylimidazolium chloride ([C2mim][Cl]) and anhydrous GaCl3 with a molar ratio of 1/1 under dry argon. The molal enthalpies of solution, ΔsHm, of [C2mim][GaCl4], were measured over a molality range of about 0.008–0.1 mol·kg−1 by a solution reaction isoperibol calorimeter at 298.15 K. Considering the hydrolization of anion [GaCl4]− in dissolution process of the IL, a new method of determining the standard molal enthalpy of solution, ΔsHm⊖, was put forward on the basis of Pitzer's mixed electrolyte solution theory so that ΔsHm⊖=−132 kJ·mol−1 and the sum of Pitzer's parameters: 4βGa,Cl(0)+4β[C2mim],Cl(0)+4Ca,[C2mim]=−0.1373076, βGa,Cl(1)L+β(1)L=0.3484209 were obtained. In terms of thermodynamic cycle and Glasser's theory of lattice energy for IL, the dissociation enthalpy of [GaCl4]−(g), ΔHdis([GaCl4]−)≈5855 kJ·mol−1, that is enthalpy change for the reaction: [GaCl4]−(g)→Ga3+(g)+4Cl−(g), was estimated.
Silver(I) Coordination Polymers of 2,11‐Dithia[3.3]paracyclophane and in situ Silver(I) Perfluoro‐dicarboxylates
Authors: LIU Shuqin , ZHANG Xiongfu , WANG Huilong , MENG Changgong , MOU Wensheng
Published: May 2009

Coordination polymers of 2,11‐dithia[3.3]paracyclopane (dtpcp) with in situ silver(I) perfluoro‐dicarboxylates characterized by single crystal X‐ray analysis are described. Their structures were found to strongly depend on the dicarboxylates. With disilver(I) tetrafluoro‐succinate [(CF2)n(COOAg)2, n=2], a 1D chain of [Ag4(dtpcp)3‐ (C2F4(CO2)2)2]·2CH3OH (1) forms in which two silver(I) ions link with two dtpcp ligands to afford a four‐numbered ring and disilver(I) tetrafluoro‐succinates link such rings. Changing the silver salt to disilver(I) hexafluoroglutarate [(CF2)n(COOAg)2, n=3] produces a 3D structure with composition of [Ag2(dtpcp)(C3F6(CO2)2)] (2), in which the disilver(I) hexafluoroglutarates connect with each other to form a 1D S‐shape chain and dtpcp ligands bridge such chains to give a 3D internet. With disilver(I) octafluoroadipate [(CF2)n(COOAg)2, n=4], 2D porous sheets of [Ag2(dtpcp)2(C4F8(CO2)2)]·2mesitylene (3) are formed. In polymer 3 four dtpcp and two octafluoroadipates are linked together by silver(I) ions to give a cavity in which two guest mesitylene molecules are located.
Effect of Pb2+ on the Kinetic and Spectral Characterization of Ribulose‐1,5‐bisphosphate Carboxylase/Oxygenase
Authors: WANG Xuming , ZE Yuguan , WU Xiao , CHEN Liang , HUANG Hao , LIU Jie , MA Linglan , HONG Fashui
Published: May 2009

Pb2+ at various concentrations was added to the purified ribulose‐1,5‐bisphosphate carboxylase/oxygenase (rubisco, E.C.4.1.1.39) in vitro to gain insight into the mechanism of molecular interactions between Pb2+ and rubisco using spectral methods. It was found that the carboxylase activity of rubisco gradually decreased with increasing concentrations of Pb2+. The kinetics constant (Km) and vmax were 1.74 mol·L−1 and 0.42 mol CO2/(mg protein·min), respectively, at a low concentration of Pb2+, and 11.82 mol·L−1 and 0.28 mol CO2/(mg protein·min), respectively, at a high concentration of Pb2+. The spectroscopy assays suggested that the Pb2+ was determined to be directly bound to rubisco; the binding site of Pb2+ to rubisco was 1.1 and the binding constants were 8.63×104 and 2.18×105 L/mol. Based on the analysis of inductively coupled plasma‐mass spectrometry (ICP‐MS) and the circular dichroism (CD) spectra, it was concluded that Pb2+ replaced Mg2+ from the catalytic center in rubisco and the binding of Pb2+ entirely altered the primary conformation of rubisco, implying that the Pb2+ coordination created a new metal ion‐active site form of rubisco, thus leading to a reduction in the carboxylase activity of rubisco.
A Simple Design to Realize Micro‐column Separation by Conventional Analytical HPLC
Authors: GONG Wenjun , ZHANG Junxia , ZHANG Yuping , ZHANG Yijun , TIAN Mengkui , WU Dafu
Published: May 2009

The conventional analytical HPLC was successfully developed for micro‐column separation by using a simple eluate splitting system, self‐preparation of packing column and on‐capillary column detector in our laboratory. Porous inlet frit in fused silica capillary was rapidly prepared by sintering stainless steel powders under 500 meshes for about 20 s. The use of such frits or metal meshes in capillary to retain C18 particles of chromatographic packing was demonstrated to be stable and specially robust with continuous packing and long chromatographic runs. Furthermore, the chromatographic behavior was detailedly evaluated by changing the flow rate and the percentage of mobile phase using the prepared capillary column. Under the optimal experimental conditions, baseline separation of the model analytes including thiourea, benzene, toluene, ethylbenzene was obtained with a high column efficiency near 70000N (plates/m) by the developed capillary‐HPLC.
Removal of Chloroform from Hydrochloride Acid Solution Using Fine Powder of Polymer as Adsorbent
Authors: LU Yingzhou , QUE Yong , LI Chunxi , MENG Hong , WANG Zihao
Published: May 2009

In order to choose a suitable adsorbent for the removal of chloroform from its hydrochloric acid solution, the adsorptive ability of some polymer adsorbents was investigated in terms of their adsorption curves in water and 20% hydrochloric acid solutions at 298.15 K, and compared with that of active carbon (AC) and solid paraffin (SP). The adsorbents studied include the fine powders of chlorinated rubber (CR), polypropylene (PP), chlorinated polypropylene (CPP) and polyvinylchloride (PVC). The results showed that the adsorption behavior followed the Langmuir equation and the adsorption ability of these adsorbents followed the order AC>PVC>CR>PP>CPP>SP. This order is basically in line with the decrease of chloro‐content of the adsorbents from PVC to SP. The adsorptivity of PVC and CR was nearly equivalent to that of AC with their saturated adsorption being about 1.4 g‐CHCl3 (g‐absorbent)−1. For all adsorbents studied, the adsorption capacity always decreases with the increase of hydrochloric acid concentration. It is showed that the commercial polymer powder of PVC or CR can be used as an efficient absorbent for the removal of chloroform from its aqueous solution for its low cost, good adsorption ability and ease of thermal desorption for recycling.
Development and Validation of Selective Spectrophotometric Methods for the Determination of Pregabalin in Pharmaceutical Preparation
Authors: ARMAĞAN Önal
Published: May 2009

Three simple, quick and sensitive methods are described for the spectrophotometric determination of pregabalin (Pgb) in pharmaceutical preparations. Among them, the first two methods are based on the reaction of Pgb as n‐electron donors with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) and 7,7,8,8‐tetracyanoquinodimethane (TCNQ) as π‐acceptors to give highly colored complex species. The colored products were quantitated spectrophotometrically at 494 and 841 nm for DDQ and TCNQ, respectively. Optimization of the different experimental conditions was conducted. Beer's law was obeyed in the concentration ranges 2.0–30.0 and 1.5–10 g·mL−1 for DDQ and TCNQ methods, respectively. The third method is based on the interaction of ninhydrin (NN) with primary amine present in the pregabaline. This reaction produces a blue coloured product in N,N‐dimethylformamide (DMF) medium, which absorbs maximally at 573 nm. Beer's law was found in the concentration range 40.0–180.0 µg·mL−1. The methods were applied successfully to the determination of this drug in pharmaceutical dosage forms.
Synthesis of β‐Hydroxy Sulfides via Thiolysis of Epoxides Using S‐Alkylisothiouronium Salts as Thiol Equivalents in Basic Aqueous Medium
Authors: ZHU Jirang , LI Ridong , GE Zemei , CHENG Tieming , LI Runtao
Published: May 2009

S‐Alkylisothiouronium salt as a nontoxic, odorless and simply operational alternative of thiol was reacted with different kinds of epoxides in basic aqueous medium at room temperature affording the β‐hydroxy sulfides with high regioselectivity in excellent yields.
Fragmentation Study of 2‐Amino‐4H‐1,3‐oxazines and Octahydro‐4‐phenyl‐2H‐pyrano[2,3‐d]pyrimidin‐2‐ones: Identification of Heterocyclic Six‐membered Ring in Three‐component Reactions
Authors: HU Nan , TAI Yuanpo , WAN Jieping , PAN Yuanjiang
Published: May 2009

The fragmentation behavior of ten 2‐amino‐4H‐1,3‐oxazines and seven octahydro‐4‐phenyl‐2H‐pyrano[2,3‐d]‐pyrimidin‐2‐ones was investigated by electrospray ionization tandem mass spectrometry (ESI‐MSn). When the precursor ions were protonated oxazines, two predominant fragmentation pathways were observed with elimination of CH2N2 and HCNO, respectively. The product ion [M+H−60]+ could be observed from both pathways. While in the type of pyrimidin‐2‐ones, only direct loss of 60 Da (urea) could be observed. The fragmentation pathways were investigated by high‐resolution mass spectrometry and deuterium‐labeling experiments, and the characteristic fragmentations presented here could be convenient for future identification of resembled derivatives, especially in high throughput screening combinatorial chemistry.
Design and Synthesis of Matrix Metalloprotease Photoaffinity Trimodular Probes
Authors: QIU Wenwei , XU Jie , LI Xin , ZHONG Li , LI Jingya , LI Jia , NAN Fajun
Published: May 2009

To explore the molecular mechanism of the matrix metalloproteinases (MMPs) in tumor processes, two photoaffinity trimodular probes were designed and synthesized based on the structure activity relationship and the following photoaffinity labelling experiments afforded positive results.
An Efficient Four‐Component, One‐Pot Synthesis of Poly‐Substituted Pyrimidines in Water
Authors: WANG Zhongqing , GE Zemei , CHENG Tieming , LI Runtao
Published: May 2009

An efficient environmentally friendly synthesis of poly‐substituted pyrimidines has been developed via a four‐component, one‐pot reaction of malononitrile, carbon disulfide, alkyl halide and S‐alkylisothiouronium salt in water at room temperature. Water as solvent, mild reaction conditions, short reaction time, simple experimental procedures, broad scope of substrates and good yields are the main advantages of this method.
Design and Synthesis of Trypanosoma brucei Active 1‐Alkyloxy and 1‐Benzyloxyadamantano 2‐Guanylhydrazones
Authors: Papanastasiou Ioannis , Tsotinis Andrew , Zoidis Grigoris , Kolocouris Nicolas , Prathalingam S. Radhika , Kelly John M.
Published: May 2009

Treating African trypanosomiasis: The synthesis and biological evaluation of novel 1‐alkyloxy and 1‐benzyloxyadamantano 2‐guanylhydrazones, their 1‐dioxa congeners and two 1‐benzyladamantano 2‐guanylhydrazones is reported. Preliminary structure–activity relationship data were elucidated and lead compounds suitable for further optimization were discovered.

magnified image
First‐Principles Quantum Calculations on the Infrared Spectrum and Vibrational Dynamics of the Guanine‐Cytosine Base Pair
Authors: Yagi Kiyoshi , Karasawa Hideyuki , Hirata So , Hirao Kimihiko
Published: May 2009

Vibrational resonance plays a vital role in manifesting a broad infrared band (>300 cm−1) and ultrafast vibrational energy relaxation (<100 femtoseconds) of the intermolecular NH stretching vibrations (see spectra).

magnified image
Functional analysis of Pcipg2 from the straminopilous plant pathogen Phytophthora capsici
Authors: Sun Wen Xiu , Jia Yong Jian , Feng Bao Zhen , O'Neill Nichole R. , Zhu Xiao Ping , Xie Bing Yan , Zhang Xiu Guo
Published: May 2009

Phytophthora capsici causes serious diseases in numerous crop plants. Polygalacturonases (PGs) are cell wall‐degrading enzymes that play an important role in pathogenesis in straminopilous pathogens. To understand PGs as they relate to the virulence of P. capsici, Pcipg2 was identified from a genomic library of a highly virulent P. capsici strain. Pcipg2 was strongly expressed during symptom development after the inoculation of pepper leaves with P. capsici. The wild protein (PCIPGII) was obtained from the expression of pcipg2 and found that increasing activity of PGs in PCIPGII‐treated pepper leaves was consistent with increasing symptom development. Asp residues in active sites within pcipg2 affected PCIPGII activity or its virulence on pepper leaves. Results show that pcipg2 is an important gene among pcipg genes, and illustrate the benefit of analyzing mechanisms of pathogenicity during the period of host/parasite interaction. genesis 47:535–544, 2009. © 2009 Wiley‐Liss, Inc.
Factor analysis of the Montgomery Aasberg depression rating scale in an elderly stroke population
Authors: Farner Lasse , Wagle Jørgen , Flekkøy Kjell , Wyller Torgeir Bruun , Fure Brynjar , Stensrød Brynhild , Engedal Knut
Published: May 2009

Background

Depression is frequent in elderly stroke patients, and the pathophysiology may involve psychological as well as organic mechanisms.

Aim

To explore construct validity of the Montgomery Aasberg Depression Rating Scale using factor analysis and investigate whether symptom clusters of depression after stroke are associated with patient characteristics.

Methods

A sample of 163 stroke patients was assessed by the Montgomery Aasberg Depression Rating Scale. Pre‐stroke assessment was accomplished by means of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), the Barthel ADL Index and patient's medical history. Post‐stroke assessment was performed with the Mini Mental State Examination (MMSE), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Star Cancellation Test, the Barthel ADL Index, the modified Rankin Scale (mRS) and the National Institute of Health Stroke Scale (NIHSS). Information was collected from the patients' records. A principal components factor analysis followed by oblique rotation was performed.

Results

Among the patients, 56.4% scored between 7 and 19 on the Montgomery Aasberg Depression Rating Scale, and 13% had a score above 19. The factor analysis resulted in three factors, called anhedonia (lassitude, inability to feel, suicidal thoughts, loss of appetite), sadness (observed sadness, reported sadness, pessimism) and agitation (inner tension, lack of concentration, disturbed sleep). Anhedonia correlated with cognitive impairment, whereas sadness correlated with sensorimotor and cranial nerve deficits. Agitation had low internal reliability and did not correlate with any systematic patients characteristics.

Conclusion

We found three distinct factors. The factor anhedonia is related to cognitive impairment, sadness to neurological impairment due to the stroke and agitation to somatic factors not directly related to the stroke. Copyright © 2009 John Wiley & Sons, Ltd.
Conditional deletion of ferritin H in mice induces loss of iron storage and liver damage #
Authors: Darshan Deepak , Vanoaica Liviu , Richman Larry , Beermann Friedrich , Kühn Lukas C.
Published: May 2009

Ferritin plays a central role in iron metabolism by acting both as iron storage and a detoxifying protein. We generated a ferritin H allele with loxP sites and studied the conditional ferritin H deletion in adult mice. Ten days after Mx-Cre induced deletion, ferritin H messenger RNA (mRNA) was below 5% in the liver, spleen, and bone marrow of deleted mice compared to control littermates. Mice lost their cellular iron stores indicating the requirement of ferritin H in iron deposition. Serum iron and transferrin saturation were slightly increased and correlated with a two-fold increased liver hepcidin 1 mRNA and a reduced duodenal DcytB mRNA level. Under a normal iron regimen, deleted mice survived for 2 years without visible disadvantage. Mice fed on a high iron diet prior to ferritin H deletion suffered from severe liver damage. Similarly, ferritin H deleted mouse embryonic fibroblasts showed rapid cell death after exposure to iron salt in the medium. This was reversed by wild-type ferritin H but not by a ferritin H mutant lacking ferroxidase activity. Cell death was preceded by an increase in cytoplasmic free iron, reactive oxygen species, and mitochondrial depolarization. Conclusion: Our results provide evidence that the iron storage function of ferritin plays a major role in preventing iron-mediated cell and tissue damage. (Hepatology 2009.)
Enhanced liver regeneration following changes induced by hepatocyte-specific genetic ablation of integrin-linked kinase #
Authors: Apte Udayan , Gkretsi Vasiliki , Bowen William C. , Mars Wendy M. , Luo Jian-Hua , Donthamsetty Shashikiran , Orr Ann , Monga Satdarshan P.S. , Wu Chuanyue , Michalopoulos George K.
Published: May 2009

Following liver regeneration after partial hepatectomy, liver grows back precisely to its original mass and does not exceed it. The mechanism regulating this “hepatostat” is not clear and no exceptions have been found to date. Although pathways initiating liver regeneration have been well studied, mechanisms involved in the termination of liver regeneration are unclear. Here, we report that integrin-linked kinase (ILK) (involved in transmission of the extracellular matrix [ECM] signaling by way of integrin receptors) and/or hepatic adaptations that ensue following ILK hepatocyte-targeted removal are critical for proper termination of liver regeneration. Following partial hepatectomy (PHx), mice with a liver-specific ILK ablation (ILK-KO-Liver) demonstrate a termination defect resulting in 58% larger liver than their original pre-PHx mass. This increase in post-PHx liver mass is due to sustained cell proliferation driven in part by increased signaling through hepatocyte growth factor (HGF), and the β-catenin pathway and Hippo kinase pathways. Conclusion: The data indicate that ECM-mediated signaling by way of ILK is essential in proper termination of liver regeneration. This is the first evidence of a defect leading to impaired termination of regeneration and excessive accumulation of liver weight following partial hepatectomy. (Hepatology 2009.)
Long-term reduction of jaundice in Gunn rats by nonviral liver-targeted delivery of Sleeping Beauty transposon #
Authors: Wang Xia , Sarkar Debi P. , Mani Prashant , Steer Clifford J. , Chen Yong , Guha Chandan , Chandrasekhar Voshavar , Chaudhuri Arabinda , Roy-Chowdhury Namita , Kren Betsy T. , Roy-Chowdhury Jayanta
Published: May 2009

Asialoglycoprotein receptor (ASGPR)-mediated endocytosis has been used to target genes to hepatocytes in vivo. However, the level and duration of transgene expression have been low because of lysosomal translocation and degradation of the DNA and lack of its integration into the host genome. In this study we packaged the DNA of interest in proteoliposomes containing the fusogenic galactose-terminated F-glycoprotein of the Sendai virus (FPL) for targeted delivery to hepatocytes. After the FPL binds to ASGPR on the hepatocyte surface, fusogenic activity of the F-protein delivers the DNA into the cytosol, bypassing the endosomal pathway. For transgene integration we designed plasmids containing one transcription unit expressing the Sleeping Beauty transposase (SB) and another expressing human uridinediphosphoglucuronate glucuronosyltransferase-1A1 (pSB-hUGT1A1). The latter was flanked by inverted/direct repeats that are substrates of SB. In cell culture, FPL-mediated delivery of the E. coli β-galactosidase gene (LacZ) resulted in transduction of ASGPR-positive cells (rat hepatocytes or Hepa1 cell line), but not of ASGPR-negative 293 cells. Intravenous injection of the FPL-entrapped pSB-hUGT1A1 (4-8 μg/day, 1-4 doses) into UGT1A1-deficient hyperbilirubinemic Gunn rats (model of Crigler-Najjar syndrome type 1) resulted in hUGT1A1 expression in 5%-10% of hepatocytes, but not in other cell types. Serum bilirubin levels declined by 30% ± 4% in 2 weeks and remained at that level throughout the 7-month study duration. With histidine containing FPL, serum bilirubin was reduced by 40% ± 5%, and bilirubin glucuronides were excreted into bile. No antibodies were detectable in the recipient rats against the F-protein or human UGT1A1. Conclusion: FPL is an efficient hepatocyte-targeted gene delivery platform in vivo that warrants further exploration toward clinical application. (Hepatology 2009.)
Potential impact of long-term nucleoside therapy on the mortality and morbidity of active chronic hepatitis B #
Authors: Toy Mehlika , Veldhuijzen Irene K. , de Man Robert A. , Richardus Jan Hendrik , Schalm Solko W.
Published: May 2009

The potential impact of long-term antiviral therapy on the burden of chronic hepatitis B has hardly been documented. The aim of this study was to estimate the effects of prolonged antiviral therapy and antiviral resistance on the mortality and morbidity of active chronic hepatitis B patients. A population cohort of chronic hepatitis B patients in the Netherlands was constructed and stratified according to 10-year age groups, prevalence of hepatitis B surface antigen, hepatitis B virus DNA level, alanine aminotransferase level, hepatitis B e antigen status, and presence of cirrhosis. A Markov model was created to mathematically simulate the cohort's progression through a finite series of health states. The analysis was performed on the basis of four scenarios: natural history, long-term therapy with a high-resistance profile drug without or with salvage, and therapy with a low-resistance profile drug. It has been estimated that there were 64,000 people (0.4%) suffering from chronic hepatitis B infection in the Netherlands in 2005, with 6521 (10%) of them having high viremia and elevated alanine aminotransferase levels. Within a 20-year period, 1725 (26%) of the 6521 patients in the active chronic hepatitis B cohort will die because of liver-related causes. Of the 5685 without cirrhosis at entry, 1671 (29%) will develop cirrhosis. Of those 836 with cirrhosis at entry, 619 (74%) will die within a 20-year period. If this active chronic hepatitis B cohort is fully detected and treated, mortality related to liver disease can be reduced by 80% if a low-resistance profile drug is chosen from the start. The effect is due to both the reduction in complications of cirrhosis and the prevention of the development of cirrhosis. Conclusion: Long-term antiviral therapy with a strategy that minimizes or controls resistance will have a major preventive effect on liver-related mortality and morbidity. (Hepatology 2009.)
Apples and oranges? Corporate rescue and functional convergence in the US and UK
Authors: McCormack Gerard
Published: May 2009

This paper challenges the standard characterisation that US law in the sphere of corporate bankruptcy is ‘pro debtor’ and UK law is ‘pro creditor’. It suggests that the traditional thesis is, at best, a potentially misleading over‐simplification. It also offers the conclusion that there is functional convergence in practice, while acknowledging that corporate rescue, as distinct from business rescue, still plays a larger role in the US. The functional convergence has partly come through the UK Enterprise Act 2002 but the paper suggests that the main move has been that of US law and practice in a UK direction with more emphasis on business disposals and speedier cases than on corporate reorganisations, as traditionally understood. This mirrors practice in the UK where the emphasis has always been on business disposals. Unfortunately, the current economic recession on both sides of the Atlantic has shone a heightened spotlight on business bankruptcy and is likely to generate further changes in practice and ultimately legislation. Copyright © 2009 John Wiley & Sons, Ltd.
Ab initio and DFT studies of the thermal rearrangement of trimethylsilyl(methyl)silylene: Remarkable rearrangements of silicon intermediates
Authors: Boo Bong Hyun , Im Suk , Lee Sungyul
Published: May 2009

A reaction scheme for the rearrangement of trimethylsilyl(methyl)silylene (Me3Si–S̈i–Me) discovered in a pioneering work of organosilicon chemistry (Wulff et al., J Am Chem Soc 1978, 100, 6236) was studied by the MP2 and DFT methods. We report a thermal reaction scheme for the rearrangement of Me3Si–
$\ddot{{\rm Si}}$–Me with the structures and energies of various silicon species along the isomerization paths, that can account for the experimentally found product ratio. The experimental product ratio is in good agreement with the theoretical one derived from the Gibbs free energy changes calculated in the present study. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Prediction of membrane spanning segments and topology in β‐barrel membrane proteins at better accuracy
Authors: Ou Yu‐yen , Chen Shu‐an , Gromiha M. Michael
Published: May 2009

Prediction of membrane spanning segments in β‐barrel outer membrane proteins (OMP) and their topology is an important problem in structural and functional genomics. In this work, we propose a method based on radial basis networks for predicting the number of β‐strands in OMPs and identifying their membrane spanning segments. Our method showed a leave‐one‐out cross validation accuracy of 96% in a set of 28 OMPs, which have the range of 8–22 β‐strand segments. The β‐strand segments in OMPs and the residues in membrane spanning segments are correctly predicted with the accuracy of 96% and 87%, respectively. We have developed a web server, TMBETAPRED‐RBF for predicting the transmembrane β‐strands from amino acid sequence and it is available at http://rbf.bioinfo.tw/∼sachen/tmrbf.html. We suggest that our method could be an effective tool for predicting the membrane spanning regions and topology of β‐barrel membrane proteins. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Using multistate free energy techniques to improve the efficiency of replica exchange accelerated molecular dynamics
Authors: Fajer Mikolai , Swift Robert V. , McCammon J. Andrew
Published: May 2009

Replica exchange accelerated molecular dynamics (REXAMD) is a method that enhances conformational sampling while retaining at least one replica on the original potential, thus avoiding the statistical problems of exponential reweighting. In this article, we study three methods that can combine the data from the accelerated replicas to enhance the estimate of properties on the original potential: weighted histogram analysis method (WHAM), pairwise multistate Bennett acceptance ratio (PBAR), and multistate Bennett acceptance ratio (MBAR). We show that the method that makes the most efficient use of equilibrium data from REXAMD simulations is the MBAR method. This observation holds for both alchemical free energy and structural observable prediction. The combination of REXAMD and MBAR should allow for more efficient scaling of the REXAMD method to larger biopolymer systems. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009
Syntheses of benzo[b]‐ and benzo[j]phenanthridines
Authors: Klemm L. H. , Weisert Annekäte
Published: May 2009

The isomeric lactams benzo[b]phenanthridine‐5(6H)‐one and benzo[j]phenanthridine‐6(5H)‐one were obtained in equal yields by Schmidt reaction on 11H‐benzo[b]fluoren‐11‐one (44% total) or by Beckmann reaction on 11H‐benzo[b]fluoren‐11‐one oxime (22% total). Reduction of the lactams with lithium aluminum hydride gave the 5, 6‐dihydro‐benzo[b]‐ and ‐[j]phenanthridines. Dehydrogenation of these dihydro derivatives produced the parent aromatic heterocycles benzo[b]‐ and benzo[j]phenanthridine in best overall yields of 20% and 12%, respectively. A few substituted benzophenanthridines were also prepared. Assignment of structures was based on ultraviolet, infrared, and n.m.r. spectra of the dihydro derivatives as well as on separate unequivocal synthesis of the isomeric benzophenanthridines.
Analogs of tetrahydrofolic acid. XXXI. Hydrophobic bonding to dihydrofolic reductase. III. Further observations on conformational aspects of hydrophobic bonding with some 5‐alkyl‐2,4‐diamino‐6‐pyrimidinols
Authors: Baker B. R. , Lourens Gerhardus J.
Published: May 2009

Thirteen 5‐alkyl ‐ 2, 4 ‐diamino ‐ 6 ‐ pyrimidinols have been compared as inhibitors of dihydrofolic reductase in an attempt to delineate some of the conformational requirements for hydrophobic bonding to the enzyme; definite conformational limitations were observed. For example, cyclohexyl and trans‐crotyl side‐chains gave inhibitors that were as effective as the n‐butyl‐6‐pyrimidinol, whereas, isoamyl was better than all three; these results indicate that the n‐butyl group complexes in a near‐staggered conformation and additional hydrophobic bonding can be obtained by branching at C3 of the butyl group. Methyl branching at C2 of the n‐butyl group also gave a better inhibitor than n‐butyl, but the 2‐methylbutyl side‐chain was only half as effective as isoamyl; in contrast, the 1‐methylbutyl side‐chain gave an inhibitor only one‐half as effective as n‐butyl. That the amount of hydrophobic bonding was simply an “extraction process” dependent upon the size of the hydrocarbon group was unequivocally eliminated.
On 1,2‐benzisoxazole‐3‐acetic acid
Authors: Casini Giovanni , Gualtieri Fulvio , Stein Maria Luisa
Published: May 2009

The proposed 6‐ and 7‐methyl‐1,2‐benzisoxazole‐3‐acetic acids (3) have been shown to be 6‐ and 7‐methyl‐4‐hydroxyimino‐2‐oxo‐chromans. The method of preparation of these unknown acids was demonstrated by the synthesis of 1,2‐benzisoxazole‐3‐acetic acid, starting from 3‐methyl‐1,2‐benzisoxazole. Comparative results of the auxin test are reported.
Ten‐π‐electron nitrogen heterocyclic compounds VI: NMR spectra, HMO calculations and bromination of some diazaindenes
Authors: Paudler William W. , Dunham David E.
Published: May 2009

The bromination of pyrrolo[1, 2‐a]pyrazine and of pyrrazolo[1, 2‐a]pyridine yields the 1,3‐dibromo and 1‐bromo derivatives, respectively. These results are in agreement with the predictions based on frontier‐electron density calculations. The nmr spectra of the compounds prepared in this study are analyzed in detail.
2,6‐Dialkylpiperazines. III. NMR spectra of the geometrical isomers of 4‐phenyl‐2,6‐dimethylpiperazine
Authors: Gallo Gian Gualberto , Vigevani Aristide
Published: May 2009

The cis and trans configurations of the two geometrical isomers of 4‐phenyl‐2,6‐dimethylpiperazine are assigned by NMR spectroscopy.
Pyrrolo[2,3‐d] pyrimidines. I. 5‐hydroxypyrrolo[2,3‐d] pyrimidines
Authors: Kim Dong Han , Santilli Arthur A.
Published: May 2009

5‐Hydroxy‐7‐alkyl‐2‐phenyl‐7H‐pyrrolo[2,3‐d]pyrimidine‐6‐carbonitriles (VIIb‐d) and 5‐hydroxy‐2‐phenyl‐7H‐pyrrolo[2,3‐d]pyrimidine‐6‐carboxylic acid, ethyl ester (VIIa) were prepared from 5‐carbethoxy‐4‐chloro‐2‐phenylpyrimidine (IV) via 4‐[(cyanomethyl)alkylamino[‐2‐phenyl‐5‐pyrimidinecarboxylic acid, ethyl esters (Vb‐d) and 4‐[(carboxymethyl)amino]‐2‐phenyl‐5‐pyrimidinecarboxylic acid, diethyl ester (Va), respectively. The hydroxy group of the pyrrolo‐[2,3‐d]pyrimidines could be methylated, acetylated and tosylated. Hydrolysis of 5‐methoxy‐7‐methyl‐2‐phenyl‐7H‐pyrrolo[2,3‐d]pyrimidine‐6‐carbonitrile (IX) afforded the corresponding amide (X).
Preparation of halomethyl‐1,3,4‐thiadiazoles. Conversion to 2‐amino‐5‐(1‐methyl‐5‐nitro‐2‐imidazolyl)‐1,3,4‐thiadiazole, an important antimicrobial agent
Authors: Remers William A. , Gibs Gabriel J. , Weiss Martin J.
Published: May 2009

A new route for the synthesis of 2‐amino‐5‐(l‐methyl‐5‐nitro‐2‐imidazolyl)‐1,3,4‐thiadiazole (1) is described. This route was based upon the preparation of 2‐amino‐5‐halomethyl‐1,3,4‐thiadiazoles by condensation of haloacetic acids with thiosemicarbazide. One of these intermediates, 2‐acetamido‐5‐dichloromethyl‐1,3,4‐thiadiazole (4), was hydrolyzed to the corresponding 5‐amino‐2‐carboxaldehyde 6, which was trapped as its oxime 5. 5‐Acetamido‐1,3,4‐thiadiazole‐2‐carbonitrile (7), formed upon dehydration of 5, was then converted into 2‐amino‐5‐(2‐imidazolyl)‐1,3,4‐thiadiazole (11) by a route based on the Pinner amidine synthesis. Methylation and nitration of the imidazole moiety then completed the preparation of 1.
The azomethine nitrene. II. Photolysis of 3‐phenyl‐ Δ2 ‐oxadiazol‐5‐one
Authors: Boyer J. H. , Frints P. J. A.
Published: May 2009

Irradiation at 2537 Å eliminates carbon dioxide from 3‐phenyl‐ Δ2‐oxadiazol‐5‐one in either methanol or dioxane. A migration of phenyl from carbon to nitrogen leads to phenylcarbodiimide (8) which tautomerizes into phenylcyanamide (10). Benzamidine (11) and the 0‐methyl ether (12) of benzamidoxime apparently result from hydrogen abstraction and insertion reactions of an intermediate unrearranged azomethine nitrene (9). More extensive fragmentation produces benzonitrile (7), which is isolated, and presumably phenylcarbene (20) to account for benzyl methyl ether (15). Generation of the carbene is discussed. The formation of 3,5‐diphenyltriazole (6), triphenyltriazine (16) and N‐cyanobenzamidine (15) remains unexplained.
Benzo[b] thiophene derivatives. XIV. Derivatives of naphtho[1,8‐c] thiophene
Authors: Campaigne K. , Knapp D. R.
Published: May 2009

In the course of our efforts to synthesize the sulfur isostere of lysergic acid, we have prepared a number of derivatives of the little known naphtho[1,8‐bc]thiophene ring system. Two previously reported compounds, 2‐bromo‐3,4‐dihydro‐5‐oxo‐5H‐naphtho[1,8‐bc]thiophene and 2‐bromo‐5‐hydroxy‐3,4‐dihydro‐5H‐naphtho[1,8‐bc] thiophene have been obtained pure for the first time, and the syntheses and spectral data of eighteen new compounds are presented. The new compounds include alcohols, ketones, and halogen derivatives of partially reduced naphtho‐[1,8‐bc] thiophene, as well as the sulfones of several of these compounds.
Reaction of 2‐aminobenzamide analogs and 2‐aminothiophenol with ethyl 3‐ethoxymethylene‐2,4‐dioxovalerate. Synthesis of pyrrolo[1,2‐α]quinazoline and pyrrolo[1,2‐a]benzothiazoline derivatives
Authors: Kurihara Takushi , Tani Tsutomu , Maeyama Sigeru , Sakamoto Yasuhiko
Published: May 2009

The reaction of ethyl 3‐ethoymethylene‐2,4‐dioxovalerate (EMDV) (1) with 2‐aminobenzamide (2), 2‐aminobenzthioamide (3), 2‐aminobenzmethylamide (4) and 3‐amino‐2‐methyl‐ or phenylpyrazole‐4‐carbox‐amides (6 and 7) produced ethyl 3‐aminomethylene‐2,4‐dioxovalerates (10, 15, 16, 18 and 19), which led to pyrrolo[1,2‐a]quinazoline‐1,5‐diones (11, 22 and 23) and pyrrolo[1,2‐a]pyrazolo[4,3‐e]pyrimidine‐1,5‐diones (24 and 25) under the acidic condition, respectively. Analogously, 2‐aminothiophenol reacted with 1 to give 21, which was subsequently derived to pyrrolo[1,2‐a]benzothiazolin‐l‐one (26) under the neutral condition. Furthermore, we prepared the heterocyclic steroidal molecules (41, 43, 45, 47, 49 and 51) by condensation of 11 and 26 with hydrazine, methylhydrazine and phenylhydrazine.
Induction asymétrique et réaction des α‐hydroxy‐oximes avec le bromure de phenylmagnésium. Synthéses stéreoselectives d'alcools aziridiniques et d'aza‐bicyclo[3.1.0]oxo‐2 oxaisothiazolidines‐1,2,3
Authors: Laurent AndrÉ , Marsura Alain , Pierre Et Jean‐Louis
Published: May 2009

Une méthode simple de synthése d'aziridines alcools (NH) est decrite: action du réactif de Grignard sur les α‐hydroxy‐oximes (solvant toluéne). Ces composés ont été cyclisés en oxo‐2 oxaisothiazolidines. L'utilisa‐tion de l'effet Overhauser permet d'attribuer une configuration à ces composés et d'en déduire celle des aziridines alcools correspondantes. Une preuve de la complexation du réactif de Grignard avec la fonction alcool est apportée par action du bromure de méthyl magnésium sur la phényl‐2 méthanol‐3 azirine. L'induc‐tion asymetrique observée est discutée à partir d'un état de transition tenant compte de la complexation du réactif de Grignard avec la fonction alcoolate.
Reissert compound studies. XXXV. Acid‐catalyzed condensations of the phthalazine reissert compound and condensations of phthalazine reissert compound salt
Authors: Bhattacharjee D. , Popp F. D.
Published: May 2009

The phthalazine Reissert compound hydrofluoroborate undergoes condensation with alkynes to give pyrrolo[2,1‐α]phthalazines and with alkenes to give 2‐(1‐phthalazyl)pyrroles. The phthalazine Reissert compound undergoes acid catalyzed condensations with some alkenes but the intermediate is of sufficient stability to be isolated. This same type of intermediate can also be isolated in the acid‐catalyzed hydrolysis of the phthalazine Reissert compound.
2‐Imidazolines. IV . 1‐Aryl‐2‐alkylthio‐4,5‐ diamino‐4,5‐dihydroimidazoles. Synthesis and properties
Authors: Meola Stefania , Rivera Elisabetta , Stradi Riccardo , Gioia Bruno
Published: May 2009

1,2‐Diimmonium salts (1) react with S‐substituted isothioureas (3) yielding 2‐alkylthio‐4,5‐diamino‐4,5‐dihydroimidazoles (4), which under mild pyrolytic conditions afforded 2‐alkylthio‐5‐aminoimidazoles (7). Imidazolines (4) and imidazoles (7) were easily desulfurated with Raney nickel affording 4,5‐diamino‐4,5‐dihydroimidazole (9) and 5‐aminoimidazole (10), respectively.
Synthesis of 1,4‐disubstituted quinolizidines
Authors: Lal Bansi , Bhedi D. N. , Dornauer H. , De Souza N. J.
Published: May 2009

Two 9,11‐seco‐aphylline derivatives and four 4‐substitutedimino‐1‐carbethoxyquinolizidines were synthesized. Conformational assignments of the predominant isomers were derived from spectral data.