bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stabilities and Spectroscopy of Hydrogen Bonding Complexes Formed by 2,4‐Bis(acrylamido)pyrimidines
Authors: ZHANG Ye , LI Ting , TENG Qi‐Wen 
Published: September 2008

AbstractHydrogen bonds play important roles to living organisms containing pyrimidine‐based derivatives. The electronic structures of the hydrogen bonding complexes formed by 2,4‐bis(acrylamido)pyrimidine (2,4‐BAAP) derivatives with 1‐substituted uracil were studied using Austin Model 1 (AM1) and density function theory (DFT) methods. The UV and NMR spectra of the complexes were calculated with the INDO/CIS (configuration interaction for singlet in intermediate neglect of differential overlap) and B3LYP/6‐31G(d) methods. It was shown that the complexes could be formed via the triple hydrogen bonding between two monomers owing to the negative binding energies. The binding energies of the complexes were weakened in the presence of substituents, but this weakening effect depended on the simultaneous influence of the electronic and steric effects. The binding energies of the complexes were also decreased owing to the formation of the isomeric complexes in the presence of piperidyl on 2,4‐BAAP. The energy gaps of the complexes were lessened in the presence of electron‐donating groups. Holes and electrons were easily injected to the complexes due to the extension of the conjugation chain. The first UV absorptions of the complexes relative to those of the parent compound were red‐shifted because of the narrow energy gaps. The chemical shifts of the carbon atoms on the CO bonds in the complexes were changed downfield.
Microcalorimetric Study on the Inhibition of Escherichia coli by Some Novel Pyridine Amide Schiff Base Derivatives
Authors: LI Chao‐Hong , ZHANG Li‐Xia , CAI Li‐Hua , LIU Yi , HU Pei‐Zhi 
Published: September 2008

AbstractThe antibacterial effect of a series of novel pyridine amide Schiff base compounds on Escherichia coli was investigated by a microcalorimetric method at 37 °C. The metabolic power‐time curves of the bacteria treated by the compounds were obtained, and the thermokinetic parameters were analyzed, from which the antibacterial activities of these compounds were evaluated. The results show that two compounds F and G have good activity on aerobic multiplying metabolism of E. coli, with the value of IC50 106 and 113 mg/L respectively, but have no effective action on the fermentation metabolism of E. coli. The action of the compounds on the non‐multiplying metabolism was investigated by taking the heat output of E. coli in the stationary phase as the guideline of the activity. The experimental results revealed that the hydrophilicity of these Schiff bases had a great influence on their antibacterial activity, which results from the bacterial cell wall structure. The antibacterial structure‐activity relationship of these Schiff base derivatives was also briefly discussed. The antibacterial activity of the compounds against E. coli was as follows: compound F>G>C>D>E>B>A.
Electrochemical and Photoelectrochemical Study of Self‐assembled Monolayer of Phytic Acid on Brass
Authors: XU Qun‐Jie , WAN Zong‐Yue , ZHOU Guo‐Ding , YIN Ren‐He , CAO Wei‐Min , LIN Chang‐Jian 
Published: September 2008

AbstractPhytic acid is an environment‐friendly reagent for processing metals. The anticorrosion and inhibiting mechanism for phytic acid monolayers self‐assembled on a brass (HSn70‐1) electrode has been investigated by using electrochemical and photocurrent response methods. The electrochemical measurements indicate that phytic acid is liable to form surface complexes on the brass electrode, and the self‐assembled monolayers (SAM) change the structure of the electric double‐layer and shift the potential of zero charge positively. The photochemical measurement indicates that the brass electrode shows a p‐type photoresponse owing to the formation of a Cu2O layer on its surface, and the presence of SAM weakens significantly the photoresponse, suggesting an excellent effect on anticorrosion, which is consistent with the EIS and polarization curve measurements. Adsorption of phytic acid was found to be typical of chemisorption, which can be reasonably described on the basis of the Langmuir isotherm.
Interactions of Ovalbumin with Ionic Surfactants
Authors: GUO Xia , YAN Hui , GUO Rong 
Published: September 2008

AbstractThe interactions of ovalbumin (OVA) with one anionic surfactant, sodium dodecyl sulfate (SDS), and two cationic surfactants, dodecyl trimethylammonium bromide (DTAB) and cetyl trimethylammonium bromide (CTAB), in water have been studied through fluorescence and UV‐Vis spectroscopies and transmission electronic microscopy, combined with the measurement of conductivity. OVA can increase the critical micelle concentrations (cmc) of SDS and CTAB but has little effect on that of DTAB. The interaction between surfactant monomer and OVA is greater than that between surfactant micelles and OVA. Moreover, SDS can make OVA unfolded while cationic surfactants cannot.
New Features on the Phase Transitions of Behenic Acid Monolayers as Unveiled by 2D‐Compressibility Coefficient
Authors: GAO Wen‐Ying , YU Zhi‐Wu 
Published: September 2008

AbstractPhase behavior of Langmuir monolayers of behenic acid (BeA) has been examined by two‐dimensional compressibility. It was found that phase transitions of BeA could be classified into two distinct categories, named Type‐I and Type‐II in this work. The former is typified by a positive peak on the compressibility‐pressure (β‐) curve, indicating the transition can occur itself in a way of collapse from the initial structure. The latter is characterized by a dropping step on the β‐ curve, implying that it cannot happen itself and the driven force is continuous compression. For BeA molecules, compressibility coefficients at the initial and final state are the same, βi=βf, for Type‐I phase transition from L2 to L2' state, whilst βi>βf for Type‐II phase transition from L2' state to S state.
Synthesis, Crystal Structure and Electrochemical Studies of Two Novel Zn(II) Complexes of Phthalic Acid and Imidazole Derivatives
Authors: LI Wei‐Hua , ZHAO Guang‐Fa , HUANG Zhao‐Ge , LIU Fa‐Qian , DING Nai‐Xiu , LIU Guang‐Ye 
Published: September 2008

AbstractTwo novel coordination polymers [Zn(pa)(vim)2]n (1) and [Zn(pa)(eim)2]n (2) (pa=phthalic acid dianion, vim=1‐vinyl‐1H‐imidazole, eim=1‐ethyl‐1H‐imidazole) have been synthesized and their structures characterized by X‐ray single crystal diffractometry and elemental analysis. Both of the complexes consist of [Zn(L)2] (L=vim for 1; eim for 2) entities linked into polymeric zigzag chains along the crystallographic c‐axis by bridging phthalate anions in the µ2‐1,2 coordination mode. The coordination around each Zn(II) atom is tetrahedral. There are only van der Waals interactions between the chains in 1, while the three‐dimensional network in 2 is assembled by CH···O contacts. The electrochemical studies reveal that redoxes of Zn2+/Zn in complexes 1 and 2 are irreversible processes.
Determination of Glucose by Affinity Adsorption Solid Substrate‐room Temperature Phosphorimetry Based on Triticum Vulgare Lectin Labeled with Silicon Dioxide Nanoparticle Containing Fluorescein Isothiocyanate
Authors: LIU Jia‐Ming , LIU hen‐Bo , LI Zhi‐Ming , HE Hang‐Xia , LIN Wei‐Nü , HUANG Ya‐Hong , WANG Fang‐Mei 
Published: September 2008

Abstract In the presence of heavy atom perturber Pb2+, silicon dioxide nanoparticle containing fluorescein isothiocyanate (FITC‐SiO2) could emit a strong and stable room temperature phosphorescence (RTP) signal on the surface of acetyl cellulose membrane (ACM). It was found in the research that a quantitative specific affinity adsorption (AA) reaction between triticum vulgare lectin (WGA) labeled with luminescent nanoparticle and glucose (G) could be carried on the surface of ACM. The product (WGA‐G‐WGA‐FITC‐SiO2) of the reaction could emit a stronger RTP signal, and the ΔIp had linear correlation to the content of G. According to the facts above, a new method to determine G by affinity adsorption solid substrate room temperature phosphorimetry (AA‐SS‐RTP) was established, based on WGA labeled with FITC‐SiO2. The detection limit (LD) of this method calculated by 3Sb/k was 0.47 pg·spot−1 (corresponding to a concentration value 1.2×10−9 g·mL−1, namely 5.3×10−9 mol·L−1), the sensitivity was high. Meanwhile, the mechanism for the determination of G by AA‐SS‐RTP was discussed.
Synthesis of Natural α ‐6‐Dehydroxy‐6‐aminoglucoglycerolipids
Authors: WU Hai‐Jun , LI Chun‐Xia , SONG Gao‐Peng , LI Ying‐Xia 
Published: September 2008

Abstract Two natural 6‐dehydroxy‐6‐aminoglucoglycerolipids were first synthesized in a convenient approach. The key step was the selective α‐glycosylation of 6‐dehydroxy‐2,3,4‐tri‐O‐benzyl‐6‐amino‐D‐glucopyranosyl trichloroacetimidate donor 10 with (S)‐isopropyleneglycerol using diethyl ether as glycosylation solvent to give 3‐O‐(2,3,4‐tri‐O‐benzyl‐6‐dehydroxy‐6‐benzyloxycarbonylamino‐α‐D‐glucopyranoyl)‐1,2‐O‐isopropylene‐sn‐glycerol 7. Removal of acetonide group of 7 and acylation with various fatty acids, then deprotection of benzyl and Cbz groups and selective acylation of the amino group afforded the marine natural glycoglycerolopids of sn‐1,2‐dipalmitoyl‐3‐(N‐palmitoyl‐6‐dehydroxy‐6‐amino‐α‐glucosyl)glycerol 3 and sn‐1‐palmitoyl‐2‐myristoyl‐3‐(N‐stearoyl‐6‐dehydroxy‐6‐amino‐α‐glucosyl)glycerol 4. The structures of the synthetic samples were identified by 1H, 13C NMR, and HRESIMS.
Microwave‐accelerated Synthesis of Some (±)‐1‐Aryl‐5‐chloroisochromans
Authors: SAEED Aamer , MUMTAZ Amara 
Published: September 2008

AbstractSolventless one‐pot synthesis of some new (±)‐1‐aryl‐5‐chloroisochromans by cyclocondensation of 2‐(2‐chlorophenyl)ethanol with aromatic aldehydes via an acid catalyzed oxa‐Pictet‐Spengler reaction under microwave irradiation is described.
Electrochemical Synthesis of 5‐Purin‐6'‐ylthiocatechols in Aqueous Medium
Authors: LIU Fu‐Jian , ZENG Cheng‐Chu , PING Da‐Wei , CAI Yuan‐Li , ZHONG Ru‐Gang 
Published: September 2008

AbstractThe electrochemical synthesis of 5‐purin‐6′‐ylthiocatechols was carried out by anodic oxidation of catechol derivatives 1a–1d in the presence of 6‐mercaptopurine (2) in aqueous solution. Results of cyclic voltammetry and controlled‐potential electrolysis indicated that the starting catechols were first oxidized to the corresponding o‐benzoquinone, which underwent further Michael addition with 6‐mercaptopurine to produce titled products 3a–3d following an EC (E=electrochemical and C=chemical step) mechanism. Such work further demonstrates the versatility of the anodic oxidation of catechols and their in‐situ transformation for the synthesis of derivatized catechols.
Asymmetric Hydrogenation of α‐Hydroxy Ketones: A Reaction Sensitive toward Electronic Effect of Substrates
Authors: XU Hui , MENG Qing‐Hua , ZHANG Zhao‐Guo 
Published: September 2008

AbstractAn efficient asymmetric hydrogenation of α‐hydroxy ketones was reported with the catalyst prepared from [RuCl2(benzene)]2 and SunPhos, chiral terminal 1,2‐diols were obtained in up to 99% ee. This Ru‐catalyzed asymmetric hydrogenation reaction of α‐hydroxy ketones represents a new route for the synthesis of chiral terminal 1,2‐diols.
Chiral Separation of Novel α ‐Aminophosphonates Containing a Benzothiazole Moiety by Liquid Chromatography Using an Amylose Stationary Phase
Authors: LU Ping , ZHANG Yu‐Ping , SONG Bao‐An , YANG Song , BHADURY Shankar Pinaki , HU De‐Yu , XUE Wei , CHEN Zhuo , JIN Lin‐Hong 
Published: September 2008

AbstractThe present report describes a chiral HPLC method for the enantiomeric separation of α‐aminophosphonate derivatives using two new coated and immobilized amylose‐based chiral stationary phases (CSP, Chiralpak IA and Chiralpak AD‐H). The chromatographic parameters such as retention factor (k), separation factor (α), and resolution (Rs) of the solutes were investigated on these two CSPs. Reasonably good baseline separation for these compounds was achieved using Chiralpak IA column. The influences of temperature, content of ethanol modifier and the structure of analyte were also studied. THF, EtOAc and CH2Cl2 were used as eluents on analytical and semi‐preparative columns. Highly enriched enantiomers with purities of up to 96.4% –100% (ee) and yields of 90.2% –95.5% were obtained, respectively. The proposed methods were found to be suitable and accurate for rapid separation and semi‐preparation of enantiomeric α‐aminophosphonate derivatives available.
New Transition and Actinide Metal Complexes of 2‐Carboxy‐phenylhydrazo‐Benzoylacetone Ligand: Synthesis, Characterization and Biological Study
Authors: KHALIL M. M. H. , MASHALY M. M. 
Published: September 2008

AbstractA new series of binary mononuclear complexes were prepared from the reaction of the hydrazone ligand, 2‐carboxyphenylhydrazo‐benzoylacetone (H2L), with the metal ions, Cd(II), Cu(II), Ni(II), Co(II), Th(IV) and UO2(VI). The binary Cu(II) complex of H2L was reacted with the ligands 1,10‐phenanthroline or 2‐aminopyridine to form mixed‐ligand complexes. The binary complexes of Cu(II) and Ni(II) are suggested to have octahedral configurations. The Cd(II) and Co(II) complexes are suggested to have tetrahedral and/or square‐planar geometries, respectively. The Th(IV) and UO2(VI) complexes are suggested to have octahedral and dodecahedral geometries, respectively. The mixed‐ligand complexes have octahedral configurations. The structures of all complexes and the corresponding thermal products were elucidated by elemental analyses, conductance, IR and electronic absorption spectra, magnetic moments, 1H NMR and TG‐DSC measurements as well as by mass spectroscopy. The ligand and some of the metal complexes were found to activate the enzyme pectinlyase.
Heterogeneous Palladium Chloride Catalyzed Ligand‐free Suzuki‐Miyaura Coupling Reactions at Ambient Temperature
Authors: WANG Min , WANG Lei 
Published: September 2008

AbstractA mild and efficient ligand‐free Suzuki‐Miyaura coupling reaction catalyzed by heterogeneous palladium chloride was developed at room temperature in a short reaction time under air atmosphere. Various phenyl iodides, bromides and activated chlorides were coupled with sodium tetraphenylborate or phenylboronic acids efficiently to afford the corresponding cross‐coupled products in good to excellent yields. Furthermore, the catalyst could be recycled up to four times without loss of its activity.
Theoretical and Experimental Studies of the Inclusion Phenomena of β‐Cyclodextrin with Organic Amines
Authors: SONG Le‐Xin , WANG Hai‐Ming , TENG Chuan‐Feng , BAI Lei , XU Peng , GUO Xue‐Qing 
Published: September 2008

AbstractThe inclusion complexations of β‐cyclodextrin (β‐CD) with ethylenediamine 1 and its three analogs, diethylenetriamine 2, triethylamine 3 and ethylene diaminetetraacetic acid 4 were examined by means of both experimental measurements and theoretical calculations. From the polarimetric method, it was found that β‐CD could form 1/1 host‐guest inclusion complexes with these guests, and the formation constants (K) of the inclusion complexes have also been determined in aqueous solution at 298.2 K. Semiempirical PM3 calculations were carried out to assess the intermolecular binding ability of β‐CD to a series of short chain aliphatic amines such as guests 1–7, cyclic aliphatic amines 8–11, and aromatic amines 12–13. The interaction processes between β‐CD and the guests were reported, and the complexation differences of β‐CD with these guests also discussed. The energy contribution from deformation energy or hydrate energy to interaction energy in the inclusion systems was found to be quite small. The stability of β‐CD inclusion complexes depended on the size fit between the host and guest. For β‐CD complexes of guests 1–4, the order of the K values from the polarimetric measurements is in good accordance with that of the absolute values of the complexation energies from PM3 calculations.
Palladium Immobilized on Silica Gel: A Novel and Reusable Catalyst for Heck Reaction
Authors: WANG Zu‐Li , WANG Lei , YAN Jin‐Can 
Published: September 2008

AbstractThe immobilization of palladium on silica gel in Heck reaction has been developed. Iodobenzenes, bromobenzenes and activated chlorobenzenes were coupled with olefins (Heck reaction) smoothly to afford the corresponding cross‐coupling products in good to excellent yields under phosphine‐ and amine‐free reaction conditions in the presence of silica gel supported palladium, Silica‐Ap‐Pd cat. as catalyst, potassium carbonate as base and DMF as solvent. Furthermore, the silica‐supported palladium catalyst 3 could be recovered and recycled by a simple filtration of the reaction solution and used for 6 consecutive trials without significant loss of its catalytic activity.
Synthesis and Antibacterial Activity of Some New 2,5‐Disubstituted‐1,3,4‐oxadiazole Derivatives
Authors: SOMANI Rakesh R. , SHIRODKAR Prabhakar Y. , KADAM Vilasrao J. 
Published: September 2008

AbstractSynthesis of some new oxadiazole derivatives starting from 1,2,3‐benzo[d]triazole‐1‐acetic hydrazide (1) is described. The target compounds 2‐(N‐substituted‐aminocarbonylmethylthio)‐5‐(1,2,3‐benzo[d]triazol‐1‐ylmethyl)‐ 1,3,4‐oxadiazole (4a–4i) and 2‐[2‐(N‐substituted‐aminocarbonyl)ethylthio]‐5‐(1,2,3‐benzo[d]triazol‐1‐ylmethyl)‐ 1,3,4‐oxadiazole (5a–5i) were obtained in good yields via cyclisation of 1 and subjected to antibacterial activity test against pathogenic bacteria. The halogen containing mono‐ and di‐substituted derivatives showed excellent antibacterial activity compared to other analogues.
Histologic associations and long‐term cancer risk in columnar cell lesions of the breast
Authors: Boulos Fouad I. , Dupont William D. , Simpson Jean F. , Schuyler Peggy A. , Sanders Melinda E. , Freudenthal Marcia E. , Page David L. 
Published: September 2008

AbstractBACKGROUND.Mammary columnar cell lesions with atypia have been receiving increased scrutiny in view of their association with atypical hyperplasia (AH) and carcinoma. However, the few retrospective outcome studies performed have failed to establish an increased risk for recurrence or carcinoma on long‐term follow‐up.METHODS.The authors evaluated the overall cancer risk for 1261 biopsies with columnar cell lesions (CCL) in 4569 women from the Nashville Breast Cohort who were biopsied between 1969 and 1988. On the basis of Schnitt and Vincent‐Salomon's classification, they also classified 229 biopsies with CCL into 3 categories: without hyperplasia or atypia, with hyperplasia lacking atypia, and with atypia. By using a nested case‐control design, they compared the risks of invasive cancer associated with these 3 categories.RESULTS.A 2‐ to 3‐fold increase in the occurrence of AH in the presence of CCL versus in their absence (P < .005) was observed. Relative risk of invasive breast cancer for women with both AH and CCL compared with those with AH alone did not differ significantly (risk ratio [RR] = 1.55; P = .29). The presence of CCL alone was associated with a mild increase in the overall cancer risk (RR = 1.47; P = .05). In the nested case‐control study, no significant risk difference was observed among the 3 categories of CCL.CONCLUSIONS.The authors observed a positive association between CCL and AH. The possibility that CCL by themselves significantly elevate breast cancer risk is not well supported. However, a finding of CCL on benign breast biopsy may indicate the presence of AH, a more worrisome lesion. Cancer 2008. © 2008 American Cancer Society.
Long‐term outcomes and clinicopathologic differences of African‐American versus white patients treated with breast conservation therapy for early‐stage breast cancer
Authors: Moran Meena S. , Yang Qifeng , Harris Lyndsay N. , Jones Beth , Tuck David P. , Haffty Bruce G. 
Published: September 2008

AbstractBACKGROUND.African–American (AA) and white patients with early–stage disease who were treated with breast conservation therapy (BCT) were examined to detect differences in clinicopathologic features and outcomes as a function of race.METHODS.Clinical data from the charts of 2164 white and 207 AA patients treated with BCT, and p53 expression status on 444 patients (from an existing tissue database), were analyzed to detect differences between the 2 cohorts.RESULTS.The median follow‐up was 7 years. There were no differences in the method of tumor detection, lymph nodes excised, surgical margin status, or chemotherapy/radiotherapy delivered, reflecting similar screening and treatment policies for AA women in the study community. Despite this, AA patient presented at a younger age, with higher T and N classifications, and more estrogen and progesterone negative and “triple negative” tumors (all P values <.016). Tumors in AA patients were p53 positive more often than tumors in white patients (P = .0003). At 10 years, AA patients had a higher rate of distant metastasis (20% vs 17%; P = .042), lymph node recurrence (6% vs 2%; P = .004), and breast recurrence (17% vs 13%; P = .036). There was no difference in overall survival between the 2 groups. On multivariate analysis, only lymph node recurrence (risk ratio of 3.140; 95% confidence interval, 1.396‐7.063 [P = .0057]) remained significantly higher among AA women.CONCLUSIONS.In this cohort of uniformly treated patients, the authors found the expected clinicopathologic differences, but race was not found to be an independent predictor of local recurrence for AA patients when other confounding variables were taken into account in the multivariate model. These findings suggest that BCT is a reasonable option for appropriately selected AA patients. To the authors' knowledge, this is the largest study addressing outcomes after BCT for AA women published to date. Cancer 2008. © 2008 American Cancer Society.
Defining potency: A comparison of the International Index of Erectile Function short version and the Expanded Prostate Cancer Index Composite
Authors: Schroeck Florian R. , Donatucci Craig F. , Smathers Emily C. , Sun Leon , Albala David M. , Polascik Thomas J. , Moul Judd W. , Krupski Tracey L. 
Published: September 2008

AbstractBACKGROUND.Both the 5‐item short version of the International Index of Erectile Function (IIEF‐5) and the Expanded Prostate Cancer Index Composite (EPIC) have been used to assess erectile function. In this study, the authors compared various definitions of potency according to the IIEF‐5 and the EPIC.METHODS.Patients with prostate cancer who had completed the IIEF‐5 and the EPIC within 7 days of each other were included. The Spearman correlation coefficient (rho) was calculated to assess the relation between IIEF‐5 and EPIC sexual domain scores. Concordance of potency rates by IIEF‐5 and EPIC was assessed in cross‐tabulations. By calculating the area under the receiver operator characteristics (ROC) curve (AUC), the authors ascertained the discriminative ability of the IIEF‐5 score to identify potent men as defined by the EPIC.RESULTS.Analyzing 102 questionnaire pairs, IIEF‐5 and EPIC domain scores were found to be highly correlated (rho = 0.776). EPIC sexual domain scores ≥60 had high concordance with IIEF‐5 scores ≥17 (98%) and with nearly all single‐item definitions of potency (≥71%). However, an EPIC sexual domain score ≥80 was a very strict definition of potency, and only 54% of patients with IIEF‐5 scores ≥22 met this threshold. On the basis of ROC analysis (AUC = 0.90), an IIEF‐5 score ≥20 was identified as the ideal cutoff for defining potency and corresponded with an EPIC sexual domain score ≥60.CONCLUSIONS.IIEF‐5 and EPIC scores were highly correlated, but potency rates varied widely, depending on the definition of potency. The current results help with the interpretation of sexual function outcomes data in patients with prostate cancer. Cancer 2008. © 2008 American Cancer Society.