bluuebunny/crossref_metadata_2025_split huggingface dataset:
Designed Reversible Alkylamine Intercalation–Deintercalation in the Layered Perovskite‐Type Oxide KCa2Nb3O10
Authors: Sun Chuansheng , Peng Peng , Zhu Lirong , Zheng Wenjun , Zhao Yongnan 
Published: July 2008

AbstractReactions have been designed to verify the reversibility of butylamine intercalation–deintercalation in the layered perovskite‐type oxide KCa2Nb3O10. The reactions include ion exchange to form HCa2Nb3O10·1.5H2O, butylamine intercalation for producing C4H9NH3Ca2Nb3O10, transformation of C4H9NH3Ca2Nb3O10 into HCONH3Ca2Nb3O10 by formamide substitution and conversion of HCONH3Ca2Nb3O10 into HCa2Nb3O10·1.5H2O again by ion exchange. The complete reaction cycles were monitored by XRD, Raman spectroscopy, thermogravimetric (TG) and elemental analysis, and the resulting information was used to propose the structure evolution and to determine the organic components of the products. The well‐matched powder X‐ray diffraction (XRD) patterns and Raman spectra between the initial and recovered protonated materials confirmed that they have identical structural features of a protonated triple‐layered perovskite. The C, H and N elemental analysis results and TG data indicate that the regenerated layered perovskite‐type oxides also have a high capacity for alkylamine intercalation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Stereoselective Synthesis of Novel Cyclic γ‐Amino Acids and Triazole Derivatives
Authors: Prazeres Verónica F. V. , Castedo Luis , González‐Bello Concepción 
Published: July 2008

AbstractFour polyhydroxylated γ‐azido and three γ‐amino acids 1–4 have been synthesized from (–)‐quinic acid. The nitrogen functionality in the reported derivatives was introduced through regioselective ring‐opening of cyclic sulfates with azide anion. The synthesis of the 4‐ and 5‐epimers of γ‐azido acid 1a – derivatives 2 and 3a, respectively – was achieved by regioselective oxidation of dibutylstannylene acetals derived from 1,2‐diols, followed by diastereoselective reduction of their corresponding α‐hydroxy ketones. The presence of the azide functional group in the reported γ‐azido acids was exploited to permit interlinking of bioactive molecular entities.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Green, Palladium‐Catalyzed Synthesis of Benzylic H‐Phosphinates from Hypophosphorous Acid and Benzylic Alcohols
Authors: Coudray Laëtitia , Montchamp Jean‐Luc 
Published: July 2008

AbstractBenzylic alcohols cross‐couple directly with concentrated H3PO2 by using Pd/xantphos (1 or 2 mol‐%). Depending on the substrate, DMF at 110 °C or t‐AmOH at reflux with a Dean–Stark trap can be used. A broad range of benzylic alcohols react successfully to give moderate to good yields of the products. The preparation of other organophosphorus compounds (phosphinic and phosphonic acids) is also demonstrated. Asymmetric reaction with (R)‐1‐(2‐naphthyl)ethanol provids the corresponding H‐phosphinic acid in 77 % ee. The methodology provides a green, PCl3‐free route to benzylic‐H‐phosphinic acids.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Oligophenylenevinylene Heptamers Substituted with Fullerene Moieties (Eur. J. Org. Chem. 21/2008)
Authors: Gégout Aline , Holler Michel , Figueira‐Duarte Teresa M. , Nierengarten Jean‐François 
Published: July 2008

AbstractThe cover picture shows a satellite‐shaped C60?oligophenylenevinylene (OPV) conjugate. This compound has been prepared starting from a fullerene carboxylic acid derivative and an OPV heptamer bearing two alcohol functions. Electrochemical investigations revealed that the fist reduction of this hybrid compound is centered on the fullerene subunits, whereas the oxidation is centered on the OPV rod. Details are discussed in the article by J.‐F. Nierengarten et al. on p. 3627 ff.
Picomolar Detection of Hydrogen Peroxide at Glassy Carbon Electrode Modified with NAD+ and Single Walled Carbon Nanotubes
Authors: Salimi Abdollah , Miranzadeh Leyla , Hallaj Rahman , Mamkhezri Hussein 
Published: July 2008

AbstractPotential cycling was used for oxidation of NAD+ and producing an electroactive redox couple which strongly adsorbed on the electrode surface modified with single walled carbon nanotubes (SWCNTs). Modified electrode shows a pair of well defined and nearly reversible redox peaks at pH range 1–13 and the response showed a surface‐controlled electrode process. The surface coverage and heterogeneous electron transfer rate constant (ks) of adsorbed redox couple onto CNTs films were about 6.32×10−10 mol cm−2 and 2.0 (±0.20) s−1, respectively, indicating the high loading ability of CNTs toward the oxidation product of NAD+ (2,8‐dihydroxy adenine dinucleotide) and great facilitation of the electron transfer between redox couple and CNTs immobilized onto electrode surface. The modified electrode exhibited excellent electrocatalytic activity for H2O2 reduction at reduced overpotential. The catalytic rate constant for H2O2 reduction was found to be 2.22(±0.20)×104 M−1 s−1. The catalytic reduction current allows the amperometric detection of H2O2 at an applied potential of −0.25 V vs. Ag/AgCl with a detection limit of 10 pM and linear response up to 100 nM and resulting analytical sensitivity 747.6 nA/pM. The remarkably low detection limit (10 pM) is the lowest value ever reported for direct H2O2 determination on the electrodes at pH 7. The modified electrode can be used for monitoring H2O2 without the need for an enzyme or enzyme mimic. The proposed method for rapid amperometric detection of H2O2 is low cost and high throughput. Furthermore, the sensor can be used to any detection scheme that uses enzymatically generated H2O2 as a reactive product in biological systems.
Simultaneous Flow Injection Analysis of Paracetamol and Ascorbic Acid with Multiple Pulse Amperometric Detection
Authors: Torres Pio dos Santos Wallans , Nascimento de Almeida Edimar Gledison , Alves Ferreira Humberto Eustáquio , Gimenes Denise Tofanello , Richter Eduardo Mathias 
Published: July 2008

AbstractThe present work reports a simple and quick strategy for simultaneous determination of paracetamol (PC) and ascorbic acid (AA) in pharmaceutical formulations using flow injection method with multiple pulse amperometric detection. The method allows the resolution of the mixture without chemical pretreatment of the sample or electrode modification or the use of chemometric techniques for data analysis. The compounds are detected by applying four sequential pulses (waveform) in function of time to a three‐electrode amperometric system that uses a wall‐jet cell with gold as working electrode. AA is direct detected at +0.40 V and PC is indirectly detected at 0.0 V by the reduction (desorption) of the oxidation product (N‐acetyl‐p‐benzoquinoneimine) electrochemically generated at +0.65 V. The fourth potential pulse (−0.05 V) is applied for the complete regeneration (cleaning) of the gold electrode surface. The linear response range was optimized between 5 and 24 mg L−1 for AA and 50 and 240 mg L−1 for PC. The difference between the two responses ranges (10‐fold) present correlation with the concentration of these compounds in two different pharmaceutical formulations available in the Brazilian market. The analytical frequency was calculated in 60 injections per hour. The use of the proposed methodology for PC quantification in the presence of higher AA concentrations was also carried out. Using the standard addition method, it was possible to detect PC in trace levels (LD=0.2 mg L−1) in the presence of 880‐fold more of AA (176 mg L−1).
Self‐Assembled Mercapto‐Compound‐Gold‐Nanoparticle‐Modified Carbon Paste Electrode for Potentiometric Determination of Cadmium(II)
Authors: Mashhadizadeh Mohammad Hossein , Eskandari Khadijeh , Foroumadi Alireza , Shafiee Abbas 
Published: July 2008

AbstractA new modified carbon paste electrode (CPE) based on a recently synthesized ligand [2‐mercapto‐5‐(3‐nitrophenyl)‐1,3,4‐thiadiazole] (MNT), self‐assembled to gold nanoparticles (GNP) as suitable carrier for Cd(II) ion with potentiometric method are described. The proposed electrode exhibits a Nernstian slope of 29.4±1.0 mV per decade for Cd(II) ion over a wide concentration range from 3.1×10−8 to 3.1×10−4 mol L−1. The detection limit of electrode was 2.0×10−8 mol L−1 of cadmium ion. The potentiometric responses of electrode based on MNT is independent of the pH of test solution in the pH range 2.0–4.0. It has quick response with response time of about 6 s. The proposed electrode show fairly good selectivity over some alkali, alkaline earth, transition and heavy metal ions. Finally, the proposed electrode was successfully employed to detect Cd(II) ion in hair and water samples.
A Cryptate Reference Electrode for Ionic Liquids
Authors: Lewandowski Andrzej , Osińska Monika , Swiderska‐Mocek Agnieszka , Galinski Maciej 
Published: July 2008

AbstractThe cryptate electrode (Ag/Ag+222), prepared by immersing silver wire in a solution of silver(I) salt and the cryptand 222 (4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane) in ionic liquids have been studied. The potential of the electrode is stabilized by the equilibrium of the Ag+ ion complexation by the cryptand, similarly to the potential stabilization by the ionic product of slightly soluble salts, used in aqueous electrodes of the second kind. The Ag/Ag+222 cryptate electrode (concentration of the cryptate was much higher than the silver(I) cation concentration, [222]>[Ag+]) may be used as a reference electrode in room temperature ionic liquids. The potential of the Ag/Ag+222 electrode is less sensitive to the presence of impurities, such as halides or water, in comparison to the Ag/Ag+ electrode. After anodic or cathodic polarization, the potential of the Ag/Ag+222 electrode comes back to the initial open circuit potential quickly. Preparation of the Ag/Ag+222 reference electrode is very easy: a silver wire is immersed in a solution of Ag+ salt and cryptand 222 (both available commercially) in the ionic liquid under study.
Electrospun Silk Fibroin Mats for Tissue Engineering
Authors: Alessandrino A. , Marelli B. , Arosio C. , Fare S. , Tanzi M. C. , Freddi G. 
Published: July 2008

AbstractProcessing Silk Fibroin (SF) with electrospinning (ES) offers a very attractive opportunity for producing a variety of 2D and 3D matrices with great potential for tissue regeneration and repair due to the superior biocompatibility and mechanical properties of SF. Different combinations of ES parameters were explored to investigate the best experimental set‐up related to the dimension and uniformity of the fibers in the electrospun silk fibroin (ES‐SF) mats. Using SEM it was found that the ES‐SF mats contain uniform fibers with a diameter in the nanometric range obtained by electrospinning a 7.5 % w/v SF solution in formic acid, with an electric field of 2.4 kV/cm and a spinneret‐collector distance of 10 cm. FT‐IR and DSC analyses were performed to investigate the structure of the ES‐SF mats before and after immersion in methanol for different times (5, 10, and 15 min). The methanol treatment was able to promote the crystallization of SF by conformational transition of random coil and other poorly ordered conformations (turns and bends) to the β‐sheet structure. The degree of crystallinity was enhanced as shown by the trend of both the FT‐IR crystallinity index and the melting/decomposition peak temperature (from DSC). To study the cytocompatibility of ES‐SF mats, tests with L929 murine fibroblasts were carried out. Samples were seeded with the cells and incubated for 1, 3, and 7 days at 37 °C. At each time point, SEM investigations and Alamar blue tests were performed. The SEM images showed cell adhesion and proliferation just after 1 day and cell confluence at 7 days. Alamar blue test demonstrated that there were very low differences between cell viability on ES‐SF mats and the tissue culture plastic control.
Towards Higher Laccase Activities Produced by Aquatic Ascomycetous Fungi Through Combination of Elicitors and an Alternative Substrate
Authors: Junghanns C. , Parra R. , Keshavarz T. , Schlosser D. 
Published: July 2008

AbstractLaccases are versatile biocatalysts with various potential biotechnological applications, e.g. the treatment of industrial waste waters, the detoxification of environmental pollutants, or the functionalization of renewable polymeric materials. Central composition experimental design and response surface methodology was applied to optimize the production of laccase by the aquatic ascomycetous fungi, Phoma sp. UHH 5‐1‐03 and Coniothyrium sp. Kl‐S5, in shake flasks. A complex plant‐based medium (tomato juice) and two elicitors (Remazol Brilliant Blue R [RBBR] and CuSO4) were tested in combination at three concentrations. The highest laccase activity of 6322 ± 403 U/L was achieved on day 9 for Phoma sp. Coniothyrium sp. exerted a maximum laccase activity of 3035 ± 111 U/L on day 4. Optimal conditions were 30 % tomato juice and 450 mg/L RBBR for both strains. A concentration of 250 μM CuSO4 led to highest laccase activities in cultures of Coniothyrium sp., and 50 μM CuSO4 was most effective for Phoma sp. A remarkable synergistic effect of tomato juice and RBBR on laccase production was observed for both strains. The upscaling potential of the optimal induction conditions was demonstrated in a lab‐scale fermenter which resulted in maximum activities of 11030 ± 177 U/L on day 6 for Phoma sp. and 11530 ± 161 U/L on day 9 for Coniothyrium sp. This study therefore presents a promising alternative for laccase production in ascomycetes based on a cheap complex substrate in combination with two elicitors.
A spatio‐temporal model for Antarctic sea ice formation
Authors: Koulis T. , Thompson M. E. , LeDrew E. 
Published: July 2008

AbstractThe temporal variability of polar sea ice is complex and closely linked to global climate. The amount of sea ice over an area can have a significant effect on the energies transferred between the atmosphere and the ocean. Statistics derived from sea ice observations are therefore of great interest to scientists. We showcase a new method of analysis which may be used to examine the annual variability in sea ice formation. We demonstrate our method using sea ice concentration images derived from Earth‐orbiting satellites that span several decades. The growth and melt of Antarctic sea ice is modelled using a simple two parameter spatial nearest neighbour process that treats ice and water as two species competing for territory. Simulations of the model are used to estimate two time series representing rates of competition. With techniques of functional data analysis, these series may be used to detect both amplitude and phase variation, and to isolate major modes of annual variation in sea ice formation. Copyright © 2008 John Wiley & Sons, Ltd.
The nature of informal caregiving for medically ill older people with and without depression
Authors: McCusker Jane , Latimer Eric , Cole Martin , Ciampi Antonio , Sewitch Maida 
Published: July 2008

AbstractObjectivesTo describe patient and caregiver perceptions of the nature of informal caregiving in a sample of older medical inpatients with and without depression.MethodsOne hundred and fifty‐four patient‐caregiver pairs were recruited from a larger prospective observational study of three groups of medical inpatients aged 65 and over, with major, minor, and no depression, respectively, and with at most mild cognitive impairment. Interviews were conducted at the time of hospital admission to assess characteristics of patients (disability, comorbidity, perceptions of support) and caregivers (relationship, residence, types of assistance and time spent caregiving). Time spent on the physical tasks of caregiving (assistance with activities of daily living, physical care, transport) was estimated by all caregivers. Time spent on emotional or other support was estimated only for non‐coresident caregiversResultsIn multivariable analyses, neither major nor minor depression was associated with time spent on physical support; major depression was associated with significantly increased time spent by non‐coresident caregivers on emotional or other support; minor depression was associated with perceived inadequacy of support.ConclusionsMajor depression is independently associated with greater time spent by non‐coresident caregivers on emotional or other support; minor depression is associated with perceived inadequacy of support. Copyright © 2008 John Wiley & Sons, Ltd.
Does increased urination frequency protect against bladder cancer?
Authors: Silverman Debra T. , Alguacil Juan , Rothman Nathaniel , Real Francisco X. , Garcia‐Closas Montserrat , Cantor Kenneth P. , Malats Nuria , Tardon Adonina , Serra Consol , Garcia‐Closas Reina , Carrato Alfredo , Lloreta Josep , Samanic Claudine , Dosemeci Mustafa , Kogevinas Manolis 
Published: July 2008

AbstractExperimental studies suggest that increased urination frequency may reduce bladder cancer risk if carcinogens are present in the urine. Only 2 small studies of the effect of increased urination frequency on bladder cancer risk in humans have been conducted with conflicting results. Our purpose was to evaluate the effect of urination frequency on risk of bladder cancer in a large, multicenter case–control study. We analyzed data based on interviews conducted with 884 patients with newly diagnosed, bladder cancer and 996 controls from 1998 to 2001 in Spain. We observed a consistent, inverse trend in risk with increasing nighttime voiding frequency in both men (p = 0.0003) and women (p = 0.07); voiding at least 2 times per night was associated with a significant, 40–50% risk reduction. The protective effect of nocturia was apparent among study participants with low, moderate and high water consumption. The risk associated with cigarette smoking was reduced by nocturia. Compared with nonsmokers who did not urinate at night, current smokers who did not urinate at night had an OR of 7.0 (95% CI = 4.7–10.2), whereas those who voided at least twice per night had an OR of 3.3 (95% CI = 1.9–5.8) (p value for trend = 0.0005). Our findings suggest a strong protective effect of nocturia on bladder cancer risk, providing evidence in humans that bladder cancer risk is related to the contact time of the urothelium with carcinogens in urine. Increased urination frequency, coupled with possible dilution of the urine from increased water intake, may diminish the effect of urinary carcinogens on bladder cancer risk. © 2008 Wiley‐Liss, Inc.
A compendium of familial relative risks of cancer among first degree relatives: A population‐based study
Authors: Zeegers Maurice P. , Schouten Leo J. , Goldbohm R. Alexandra , van den Brandt Piet A. 
Published: July 2008

AbstractFamilial clustering of cancer is expected to occur at practically all anatomical sites. However, few studies have had sufficient size to investigate different sites simultaneously and with adjustment for confounders. We evaluated familial clustering in the Netherlands Cohort Study in which 120,852 men and women, aged 55–69 years in 1986 were followed up for 13.3 years. 14,025 Probands, 6,629 parents and 4,271 siblings were diagnosed with cancer. Relative Risks (RR) of cancer in first degree family members were calculated by using multivariable Cox regression analyses. We also calculated false‐positive reporting probabilities. Significant concordant familial clustering was observed for stomach (RRfather = 1.89, RRparent = 1.66, RRsister = 3.33, RRsibling = 2.38, RR1st degree = 1.69), colon/rectum (RRfather = 1.82, RRmother = 1.83, RRparent = 1.88, RR1st degree = 1.56), lung (RRbrother = 1.50) and breast cancer (RRmother = 1.65, RRsister = 1.72, RR1st degree = 1.72) with low false‐positive reporting probabilities. Significant discordant familial clustering has been observed for combinations of pancreas‐colon/rectum (RRmother = 2.42, RRparent = 1.89, RR1st degree = 1.73), larynx‐lung (RRfather = 3.35, RRparent = 2.84, RR1st degree = 2.30), lung‐oesophagus (RRsibling = 3.49), breast‐bladder (RRfather = 2.79, RRparent = 2.61), endometrium‐stomach (RRmother = 2.32), ovarium‐oesophagus (RR1stdegree = 4.19), prostate‐colon/rectum (RRparent = 1.46) and bladder‐larynx/pharynx (RRfather = 2.49) cancer, although false‐positive reporting probabilities were higher for these associations. Familial clustering of cancer occurs at most sites but is generally modest. Some observed discordant familial clustering is surprising but should be interpreted with caution as their prior probability is low. © 2008 Wiley‐Liss, Inc.
Bidi smoking and lung cancer incidence among males in Karunagappally cohort in Kerala, India
Authors: Jayalekshmy Padmavathy Amma , Akiba Suminori , Nair Madhavan Krishnan , Gangadharan Paleth , Rajan Balakrishnan , Nair Reghuram K. , Sugahara Tsutomu 
Published: July 2008

AbstractThe association of lung cancer incidence with bidi smoking was examined using a cohort study data in Karunagappally, Kerala, India. We sought interview of all the residents in Karunagappally with the population of 385,103 in 1991 census, and established a cohort of 359,619 (93% of the population in 1991) in the 1990s. There were 65,829 men aged 30–84 at interview after excluding those diagnosed as cancer or died of any cause before 1997. Among them, 212 newly diagnosed lung cancer cases were ascertained during the 8‐year period between 1997 and 2004 through Karunagappally Cancer Registry. The relative risk (RR) of lung cancer was obtained from Poisson regression analysis of grouped data. Lung cancer incidence was relatively high among Moslem people and those with lower educational history. When taking into account attained age, religion and education, the RR between current bidi smokers and those who had never smoked bidis was 3.9 (95%CI = 2.6–6.0, p < 0.001). The lung cancer risk did not return to the level of non‐smokers within 10 years after cessation. In further analyses using only those never smoked cigarettes to examine the effect of bidi smoking alone on lung cancer risk, current smokers of bidis had the RR of 4.6 (95%CI = 2.5–8.5, p < 0.001). Lung cancer incidence increased with larger amounts of bidi smoked a day (p < 0.001), with longer durations of smoking bidis (p < 0.001), and with younger ages starting smoking bidis (p < 0.001). Immediate measures should be taken to stop bidi smoking, which is common in south Asia. © 2008 Wiley‐Liss, Inc.
Effect of soybean on breast cancer according to receptor status: A case–control study in Japan
Authors: Suzuki Takeshi , Matsuo Keitaro , Tsunoda Nobuyuki , Hirose Kaoru , Hiraki Akio , Kawase Takakazu , Yamashita Toshinari , Iwata Hiroji , Tanaka Hideo , Tajima Kazuo 
Published: July 2008

AbstractThe possible association of high soy food consumption with low incidence of breast cancer in Asian countries has been widely investigated, but findings from epidemiologic studies have been inconsistent. Breast cancers defined by receptor status, estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) may have distinct etiologic factors. Here, we conducted a case–control study to clarify associations between intake of soybean products and breast cancer risk according to receptor status. A total of 678 breast cancer cases and 3,390 age‐ and menopausal status‐matched noncancer controls were included. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using conditional logistic models adjusted for potential confounders. On analysis according to receptor status, we observed a significantly reduced risk of ER‐positive (ER+) (top tertile OR = 0.74; 95% CI, 0.58–0.94; trend p = 0.01) and HER2‐negative (HER2−) tumors (top tertile OR = 0.78; 95% CI, 0.61–0.99; trend p = 0.04). Further, when the 3 receptors were jointly examined, a reduced risk was observed only in patients with ER+/PR+/HER2− tumor (top tertile OR = 0.73; 95% CI, 0.54–0.97; trend p = 0.03). These findings indicate that the protective effect of soy against breast cancer risk differs by receptor status. © 2008 Wiley‐Liss, Inc.