bluuebunny/crossref_metadata_2025 huggingface dataset:
Lower critical solution temperatures of thermo‐responsive poly(N‐isopropylacrylamide) copolymers with racemate or single enantiomer groups
Authors: Li Peng‐Fei , Wang Wei , Xie Rui , Yang Mei , Ju Xiao‐Jie , Chu Liang‐Yin
Published: December 2008

BACKGROUND: Thermo‐responsive copolymers with racemate or single enantiomer groups are attracting increasing attention due to their fascinating functional properties and potential applications. However, there is a lack of systematic information about the lower critical solution temperature (LCST) of poly(N‐isopropylacrylamide)‐based thermo‐responsive chiral recognition systems. In this study, a series of thermo‐responsive chiral recognition copolymers, poly[(N‐isopropylacrylamide)‐co‐(N‐(S)‐sec‐butylacrylamide)] (PN‐S‐B) and poly[(N‐isopropylacrylamide)‐co‐(N‐(R,S)‐sec‐butylacrylamide)] (PN‐R,S‐B), with different molar compositions, were prepared. The effects of heating and cooling processes, optical activity and amount of chiral recognition groups in the copolymers on the LCSTs of the prepared copolymers were systematically studied.

RESULTS: LCST hysteresis phenomena are found in the phase transition processes of PN‐S‐B and PN‐R,S‐B copolymers in a heating and cooling cycle. The LCSTs of PN‐S‐B and PN‐R,S‐B during the heating process are higher than those during the cooling process. With similar molar ratios of N‐isopropylacrylamide groups in the copolymers, the LCST of the copolymer containing a single enantiomer (PN‐S‐B) is lower than that of the copolymer containing racemate (PN‐R,S‐B) due to the steric structural difference. The LCSTs of PN‐R,S‐B copolymers are in inverse proportion to the molar contents of the hydrophobic R,S‐B moieties in these copolymers.

CONCLUSION: The results provide valuable guidance for designing and fabricating thermo‐responsive chiral recognition systems with desired LCSTs. Copyright © 2008 Society of Chemical Industry
Effect of hydrophobic monomer on the synthesis and swelling behaviour of a collagen‐graft‐poly[(acrylic acid)‐co‐(sodium acrylate)] hydrogel
Authors: Marandi Gholam Bagheri , Hariri Safoura , Mahdavinia Gholam Reza
Published: December 2008

BACKGROUND: Graft polymerization of vinylic monomers onto natural backbones is an efficient approach for the synthesis of natural‐based superabsorbents. The nature of the monomers will affect the swelling behaviour of the superabsorbents. Here, a novel superabsorbent was synthesized through grafting of acrylic acid onto collagen in the presence of hydrophobic styrene as co‐monomer. Subsequently, the effect of styrene on the swelling behaviour of the superabsorbent was studied.

RESULTS: The highly swelling superabsorbent was prepared by introducing styrene into a collagen‐graft‐poly(acrylic acid) hydrogel. By inclusion of styrene monomer, the swelling capacity of the hydrogel was increased; this is discussed according to the network composition. The effect of swelling media (salt solutions and various pH values) was investigated. The results of absorbency under load showed that hydrogels containing phenyl groups exhibit better behaviour; however, by introducing styrene, the rate of water uptake and resistance to water holding under heating was reduced. Scanning electron micrographs of hydrogels revealed a decrease in porosity on using styrene.

CONCLUSION: Inclusion of styrene monomer in the ionic superabsorbent caused high swelling capacity with better absorbency under load. This can be used to prepare highly swelling superabsorbents with good mechanical properties. The pH reversibility of the synthesized superabsorbent makes it a candidate for use in the controlled release of drugs and in agrochemicals. Copyright © 2008 Society of Chemical Industry
Substituent effects in the Baeyer–Villiger reaction of acetophenones: a theoretical study
Authors: Reyes Lino , Alvarez‐Idaboy J. Raul , Mora‐Diez Nelaine
Published: December 2008

This paper reports the first complete theoretical study of substituent effects on the mechanism of the Baeyer– Villiger (BV) reaction in non‐polar solvents taking into account the lowest‐energy mechanism that has been proposed for this rearrangement which is non‐ionic and fully concerted. The BV reaction of p‐substituted acetophenones, p‐XC6H4COCH3 (X = NO2, CN, H, CH3, OCH3), with performic (PFA) and trifluoroperacetic (TFPAA) acids, catalyzed by formic (FA) and trifluoroacetic (TFAA) acids, respectively, using the MPWB1K functional and the 6‐311G(d,p) and 6‐311++G(d,p) basis sets, are studied. Solvent effects are taken into account by means of the PCM continuum model using dichloromethane as solvent. Electron‐donating substituents on the aryl group have a relatively small activation effect on the first step, but a pronounced activation effect on the second to the point of being able to change the rate‐determining step (RDS) of the reaction, as observed in the case of p‐methoxyacetophenone with TFPAA acids. After analyzing the changes in Gibbs free energy of activation, geometrical parameters, and charge distributions of the transition states (TSs), explanations are provided for the two distinct effects that substituents on the ketone have on the kinetics of the addition and migration steps of the BV oxidation. The effect of the acid/peracid pair used is also discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Nucleophilic and acid catalyst behavior of a protic ionic liquid in a molecular reaction media. Part 1
Authors: Adam Claudia G. , Fortunato Graciela G. , Mancini Pedro M.
Published: December 2008

This work presents a new approach using ionic liquids, namely ethylammonium nitrate. The aim was to analyze how the addition of small amounts of a protic ionic liquid to a pure molecular solvent, modifies the microscopic characteristics of a reaction medium. In order to achieve this, a kinetic study of nucleophilic aromatic substitution reactions between 1‐fluoro‐2,4‐dinitrobenzene and 1‐butylamine or piperidine was developed in this type of binary mixtures. We have detected nucleophiles competition originated by the presence of the ionic solvent at very low concentrations, observing the ethylamine derivative as the main substitution product. Moreover, in the light of previous results we have confirmed that the protic ionic liquid can act as both Brönsted acid and/or nucleophile. In this connection, we have selected the nucleophilic addition of amines to carbonyl compounds as reaction model. The protic ionic liquid in the presence of aromatic aldehydes substituted by electron‐donating groups makes possible the formation of the corresponding imines with good yields. The results demonstrated that the influence of the protic ionic liquid is very important in the course of both reaction systems. Copyright © 2008 John Wiley & Sons, Ltd.
Association of reported prostate cancer risk alleles with PSA levels among men without a diagnosis of prostate cancer
Authors: Wiklund Fredrik , Zheng S. Lilly , Sun Jielin , Adami Hans‐Olov , Lilja Hans , Hsu Fang‐Chi , Stattin Pär , Adolfsson Jan , Cramer Scott D. , Duggan David , Carpten John D. , Chang Bao‐Li , Isaacs William B. , Grönberg Henrik , Xu Jianfeng
Published: December 2008

BACKGROUND

Prostate specific antigen (PSA) is widely used for prostate cancer screening but its levels are influenced by many non cancer‐related factors. The goal of the study is to estimate the effect of genetic variants on PSA levels.

METHODS

We evaluated the association of SNPs that were reported to be associated with prostate cancer risk in recent genome‐wide association studies with plasma PSA levels in a Swedish study population, including 1,722 control subjects without a diagnosis of prostate cancer.

RESULTS

Of the 16 SNPs analyzed in control subjects, significant associations with PSA levels (P ≤ 0.05) were found for six SNPs. These six SNPs had a cumulative effect on PSA levels; the mean PSA levels in men were almost twofold increased across increasing quintile of number of PSA associated alleles, P‐trend = 3.4 × 10−14. In this Swedish study population risk allele frequencies were similar among T1c case patients (cancer detected by elevated PSA levels alone) as compared to T2 and above prostate cancer case patients.

CONCLUSIONS

Results from this study may have two important clinical implications. The cumulative effect of six SNPs on PSA levels suggests genetic‐specific PSA cutoff values may be used to improve the discriminatory performance of this test for prostate cancer; and the dual associations of these SNPs with PSA levels and prostate cancer risk raise a concern that some of reported prostate cancer risk‐associated SNPs may be confounded by the prevalent use of PSA screening. Prostate 69:419–427, 2009. © 2008 Wiley‐Liss, Inc.
The discovery of HNPC‐A3066: a novel strobilurin acaricide
Authors: Liu Aiping , Wang Xiaoguang , Chen Can , Pei Hui , Mao Chunhui , Wang Yongjiang , He Haijun , Huang Lu , Liu Xinping , Hu Zhibin , Ou Xiaoming , Huang Mingzhi , Yao Jianren
Published: December 2008

BACKGROUND: Although more than ten strobilurin analogues have been commercialized since 1996 as fungicides, only one was available as an acaricide as of 2003. To search for novel strobilurin analogues with unique biological activities, a synthetic screening programme was carried out.

RESULTS: Syntheses of compounds analogous to the commercialized fungicide metominostrobin and the acaricide fluacrypyrim led to the discovery of a lead compound, (E)‐2‐{2‐[[3,5‐bis(trifluoromethyl)phenoxy]methyl]phenyl}‐2‐(methoxyimino)‐N‐methylacetamide (3b), that showed moderate acaricidal activity against Tetranychus urticae Koch. Compound 3b has a 3,5‐(CF3)2‐phenoxymethyl group instead of the unsubstituted phenoxy substituent in metominostrobin. Optimization of compound 3b was achieved by introducing an oxime ether bridge along with an alkylthio(alkyl) branch in place of the oxymethylene chain between two aromatic moieties, as well as by replacing the methoxyiminoacetamide group with a methoxyacrylate structure, leading to (E)‐ methyl 2‐{2‐[[[(Z)[1‐(3,5‐bis(trifluoromethyl)phenyl)‐2‐methylthioethylidene]amino]oxy] methyl]phenyl}‐3‐methoxyacrylate (6c) and (E)‐ methyl 2‐{2‐[[[(Z)[1‐(3,5‐bis(trifluoromethyl)phenyl)‐1‐methylthiomethylidene]amino]oxy]methyl]phenyl}‐3‐methoxyacrylate (9a, HNPC‐A3066).

CONCLUSION: The above two compounds (6c, 9a) were shown to exhibit potent acaricidal and fungicidal activity. Compound 9a (HNPC‐A3066) also exhibits larvicidal and ovicidal activities against various acarids. The acaricidal potency is comparable with those of commercial acaricides such as fluacrypyrim, tebufenpyrad and chlorfenapyr. Copyright © 2008 Society of Chemical Industry
Current status of insecticide resistance in Q biotype Bemisia tabaci populations from Crete
Authors: Roditakis Emmanouil , Grispou Maria , Morou Evangelia , Kristoffersen Jon Bent , Roditakis Nikos , Nauen Ralf , Vontas John , Tsagkarakou Anastasia
Published: December 2008

BACKGROUND: A major problem of crop protection in Crete, Greece, is the control of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) with chemical insecticides owing to the rapid development of resistance. The aim of this study was to investigate the establishment of resistance and the underlying mechanisms to major insecticide classes with classical bioassays and known biochemical resistance markers.

RESULTS: During a 2005–2007 survey, 53 Q biotype populations were collected. Application history records showed extensive use of neonicotinoids, organophosphates, carbamates and pyrethroids. High resistance levels were identified in the majority of populations (>80%) for imidacloprid (RF: 38–1958×) and α‐cypermethrin (RF: 30–600×). Low resistance levels (RF < 12) were observed for pirimiphos‐methyl. A strong correlation between resistance to imidacloprid and the number of applications with neonicotinoids was observed. Significant correlations were observed between COE and P450‐dependent monoxygenase activity with resistance to α‐cypermethrin and imidacloprid respectively. A propoxur‐based AChE diagnostic test indicated that iAChE was widespread in most populations. Resistance levels for α‐cypermethrin were increased when compared with a previous survey (2002–2003). Differentiation of LC50 values between localities was observed for imidacloprid only.

CONCLUSION: Bemisia tabaci resistance evolved differently in each of the three insecticides studied. Imidacloprid resistance seems less established and less persistent than α‐cypermethrin resistance. The low resistance levels for pirimiphos‐methyl suggest absence of cross‐resistance with other organophosphates or carbamates used. Copyright © 2008 Society of Chemical Industry
Insecticidal activities of leaf and twig essential oils from Clausena excavata against Aedes aegypti and Aedes albopictus larvae
Authors: Cheng Sen‐Sung , Chang Hui‐Ting , Lin Chun‐Ya , Chen Pin‐Sheng , Huang Chin‐Gi , Chen Wei‐June , Chang Shang‐Tzen
Published: December 2008

BACKGROUND: The current study investigates, for the first time, the mosquito larvicidal activities of leaf and twig essential oils from Clausena excavata Burm. f. and their individual constituents against Aedes aegypti L. and Aedes albopictus Skuse larvae. The yields of essential oils obtained from hydrodistillation were compared, and their constituents were determined by GC‐MS analyses.

RESULTS: The LC50 values of leaf and twig essential oils against fourth‐instar larvae of Ae. aegypti and Ae. albopictus were 37.1–40.1 µg mL−1 and 41.1–41.2 µg mL−1 respectively. This study demonstrated that C. excavata leaf and twig essential oils possess mosquito larvicidal activity, inhibiting the growth of mosquito larvae for both species at a low concentration. In addition, results of larvicidal assays showed that the effective constituents in leaf and twig essential oils were limonene, γ‐terpinene, terpinolene, β‐myrcene, 3‐carene and p‐cymene. The LC50 values of these constituents against both mosquito larvae were below 50 µg mL−1. Among these effective constituents, limonene had the best mosquito larvicidal activity, with LC50 of 19.4 µg mL−1 and 15.0 µg mL−1 against Ae. aegypti and Ae. albopictus larvae respectively.

CONCLUSION: The findings suggested that the essential oils from Clausena excavata leaf and twig and their effective constituents may be explored as a potential natural larvicide. Copyright © 2008 Society of Chemical Industry
Off‐pump, minimally invasive and robotic coronary revascularization yield improved outcomes over traditional on‐pump CABG
Authors: Atluri Pavan , Kozin Elliott D. , Hiesinger William , Joseph Woo Y.
Published: December 2008

Coronary artery disease is a global health concern, with increasing morbidity and mortality. Surgical coronary artery bypass grafting has been performed on cardiopulmonary bypass for nearly four decades, with excellent long‐term durability. Beating‐heart coronary surgery has been increasing in frequency in an attempt to decrease cardiopulmonary bypass‐related morbidity. Furthermore, with increasing expertise and technology, minimally invasive and robotic techniques have been developed to enhance post‐operative recovery, patient satisfaction and cosmesis. Several clinical trials have demonstrated decreased morbidity and more rapid recovery following off‐pump, minimally invasive and robotic procedures when compared to on‐pump coronary artery bypass grafts (CABGs). An equivalent extent of revascularization and medium‐term anastomotic patency has been demonstrated among all approaches. Furthermore, for a large number of patients who do not have anatomy amenable to traditional coronary revascularization, adjunctive molecular therapies may provide alternative myocardial micro‐revascularization. Copyright © 2008 John Wiley & Sons, Ltd.
Making the most of what you have: managerial ability as a source of resource value creation
Authors: Holcomb Tim R. , Holmes Jr. R. Michael , Connelly Brian L.
Published: December 2008

The current study investigates a central premise of the resource‐based view of the firm—that managers are a potential source of value creation for the firm. Using data from professional sports teams, we test theory regarding the effects of managerial ability, human resource stocks, and managers' actions on resource value creation. While results indicate managerial ability affects resource productivity, this effect is less pronounced with increases in the quality of firm resources. Further, we investigate the extent to which managerial actions that synchronize resource bundles account for the influence of managerial ability and resource context on a firm's performance advantage. These results contribute to our understanding of resource management and provide empirical evidence for the importance of managerial ability in the resource‐based view. Copyright © 2008 John Wiley & Sons, Ltd.
Do VCs matter? the importance of owners on performance variance in start‐up firms
Authors: Fitza Markus , Matusik Sharon F. , Mosakowski Elaine
Published: December 2008

Adding to the corporate effect literature, we study the effect of owners on firm performance in a new context, that of venture capital firms (VCs) and the start‐up firms in which they invest. After discussing the effect that VC ownership can have on start‐ups, we estimate that start‐up‐specific, owner (VC), and year effects account for significant variance in performance (26.3 percent, 11.2 percent and 3.7 percent, respectively). The effects of industry and investment stage are not statistically different from zero. We also provide an analysis that separates the owner effect into two components: a selection component—which impacts investment—and a management component—which explains significant variance in performance. By examining the owner effect in a different institutionalized form of governance—that of the start‐up and its relationship to VC owners—our study also contributes to an understanding of the ‘ownership’ effect in the strategy literature more generally. Copyright © 2008 John Wiley & Sons, Ltd.
Controlled Deposition of Silver Nanoparticles in Mesoporous Single‐ or Multilayer Thin Films: From Tuned Pore Filling to Selective Spatial Location of Nanometric Objects
Authors: Fuertes M. C. , Marchena M. , Marchi M. C. , Wolosiuk A. , Soler‐Illia G. J. A. A.
Published: December 2008

Silver nanoparticle assemblies are embedded within mesoporous oxide thin films by an in situ mild reduction leading to nanoparticle–mesoporous oxide thin‐film composites (NP@MOTF). A quantitative method based on X‐ray reflectivity is developed and validated with energy dispersive spectroscopy in order to assess pore filling. The use of dilute formaldehyde solutions leads to control over the formation of silver nanoparticles within mesoporous titania films. Inclusion of silver nanoparticles in mesoporous silica requires more drastic conditions. This difference in reactivity can be exploited to selectively synthesize nanoparticles in a predetermined layer of a multilayered mesoporous stack leading to complex 1D‐ordered multilayers with precise spatial location of nanometric objects. The metal oxide nanocomposites synthesized have potential applications in catalysis, optical devices, surface‐enhanced Raman scattering, and metal enhancement fluorescence.
Presynaptic and postsynaptic modulation of glutamatergic synaptic transmission by activation of α1‐ and β‐adrenoceptors in layer V pyramidal neurons of rat cerebral cortex
Authors: Kobayashi Masayuki , Kojima Masao , Koyanagi Yuko , Adachi Kazunori , Imamura Kazuyuki , Koshikawa Noriaki
Published: December 2008

Adrenergic agonists have different modulatory effects on excitatory synaptic transmission depending on the receptor subtypes involved. The present study examined the loci of α1‐ and β‐adrenoceptor agonists, which have opposite effects on excitatory neural transmission, involved in modulation of glutamatergic transmission in layer V pyramidal cells of rat cerebral cortex. Phenylephrine, an α1‐adrenoceptor agonist, suppressed the amplitude of AMPA receptor‐mediated excitatory postsynaptic currents evoked by repetitive electrical stimulation (eEPSCs, 10 pulses at 33 Hz). The coefficient of variation (CV) of the 1st eEPSC amplitude and paired‐pulse ratio (PPR), which were sensitive to extracellular Ca2+ concentration, were not affected by phenylephrine. Phenylephrine suppressed miniature EPSC (mEPSC) amplitude without changing its frequency. In contrast, isoproterenol, a β‐adrenoceptor agonist, strongly increased the amplitude of the 1st eEPSC compared with that of the 2nd to 10th eEPSCs, which resulted in a decrease in PPR. Isoproterenol‐induced enhancement of eEPSC amplitude was accompanied by a decrease in CV. Isoproterenol increased the frequency of mEPSCs without significant effect on amplitude. Phenylephrine suppressed inward currents evoked by puff application of glutamate, AMPA, or NMDA, whereas isoproterenol application was not accompanied by significant changes in these inward currents. These findings suggest that phenylephrine decreases eEPSCs through postsynaptic AMPA or NMDA receptors, while the effects of isoproterenol are mediated by facilitation of glutamate release from presynaptic terminals without effect on postsynaptic glutamate receptors. These two different mechanisms of modulation of excitatory synaptic transmission may improve the “signal‐to‐noise ratio” in cerebral cortex. Synapse 63:269–281, 2009. © 2008 Wiley‐Liss, Inc.
Differential regulation of prodynophin, c‐fos, and serotonin transporter mRNA following withdrawal from a chronic, escalating dose regimen of D‐amphetamine
Authors: Horner Kristen A. , Noble Erika S. , Lauterbach Edward C.
Published: December 2008

Several lines of evidence suggest that D‐amphetamine (D‐AMPH) withdrawal induces a syndrome with symptoms similar to major depressive disorder (MDD). Upregulation of dynorphin (DYN) may underlie the symptoms of MDD and contribute to the negative emotional symptoms associated with psychostimulant withdrawal. Changes in the serotonin transporter (SERT) have also been reported in MDD, and changes in the immediate early gene c‐fos have been observed in the context of psychostimulant withdrawal. This study examined the effects of chronic, escalating doses of D‐AMPH followed by 24 h of withdrawal on the expression of prodynorphin (PD) and c‐fos mRNA in limbic regions of the brain, caudate putamen (CPu), and brainstem and SERT mRNA expression in the dorsal raphe nucleus (DRN). Male Sprague‐Dawley rats were treated three times a day for 4 days with escalating doses of D‐AMPH (1–10 mg/kg) and sacrificed 24 h after the last injection. Following 24 h of withdrawal, there was an increase in PD and c‐fos mRNA expression in the CPu and nucleus accumbens (NAc), and a decrease in PD and c‐fos expression in hippocampus and amygdala. SERT mRNA expression was decreased in the DRN, and PD mRNA expression was increased in the adjacent ventrolateral periaqueductal gray (VLPAG) following D‐AMPH withdrawal. These data indicate that region‐specific changes in PD and c‐fos expression occur after withdrawal, while SERT mRNA expression is suppressed, similar to what has been reported in MDD. Alterations in PD, c‐fos, and SERT expression could contribute to the depression‐like syndrome associated with psychostimulant withdrawal. Synapse 63:257–268, 2009. © 2008 Wiley‐Liss, Inc.
Pregnancy outcome after ultrasound diagnosis of fetal intra‐abdominal umbilical vein varix
Authors: Byers B. D. , Goharkhay N. , Mateus J. , Ward K. K. , Munn M. B. , Wen T. S.
Published: December 2008

Objectives

Fetal intra‐abdominal umbilical vein (FIUV) varix is a focal dilatation of the intra‐abdominal portion of the umbilical vein, which has been reported to be associated with intrauterine death and other anomalies. Our aim was to examine our experience with this diagnosis at a single tertiary‐care center and to correlate it with clinical outcome.

Methods

This was a retrospective case series study. Our ultrasound database was searched for all cases with a diagnosis of FIUV varix identified at our facility between 1997 and 2007. We reviewed all ultrasound examinations, maternal antenatal records, delivery records and newborns' medical records.

Results

We identified 52 cases of FIUV among a population of approximately 68 000. Three cases of trisomy 21 were identified, all of which were accompanied by other anomalies. There was intrauterine death of one fetus with trisomy 21 at 35 weeks of gestation. We did not find an association between FIUV varix and other obstetric complications.

Conclusions

The outcome of pregnancies with FIUV varix is generally favorable. The finding of a FIUV varix should prompt the search for other anomalies, especially markers of aneuploidy. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Fetal crown–rump length and estimation of gestational age in an ethnic Chinese population
Authors: Sahota D. S. , Leung T. Y. , Leung T. N. , Chan O. K. , Lau T. K.
Published: December 2008

Objectives

To develop a sonographic dating formula based on fetal crown–rump length (CRL) in a Hong Kong Chinese population, quantify its systematic prediction error and compare its performance with established dating formulae.

Methods

This was a prospective observational study of women with a spontaneously conceived singleton pregnancy and a regular menstrual cycle in the preceding 12‐month period. Ultrasound examinations were performed at gestational ages ranging from 6 to 15 + 6 weeks according to menstrual dates. The CRL of each fetus was measured three times, the mean of which was used to derive the best‐fit fractional polynomial regression model for estimation of gestational age in relation to CRL. For each fetus, the menstrual age was compared to the gestational age calculated using three established dating formulae based on CRL measurement. The mean of the differences between estimated and menstrual age was calculated for each formula.

Results

Of the 394 subjects recruited one was excluded as the pregnancy resulted in intrauterine demise. The best‐fit equation for the sonographic estimate of gestational age (GA, in days) from CRL (in mm) was GA = 26.643 + 7.822 × CRL1/2(R2 = 0.96). The mean difference between menstrual age and the predicted gestational age was 0.22 days (95% CI, − 0.14 to 0.56), which was lower than that of the three established CRL dating formulae.

Conclusion

We have derived a formula suitable for the dating of naturally conceived pregnancies between 6 and 15 weeks of gestation that has no systematic prediction error (the 95% CI of mean difference between predicted and menstrual age included zero), comparing favorably with established CRL dating formulae. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Super‐volcanic eruptions: a historical background
Authors: Schröder Wilfried
Published: December 2008

This letter refers to WEA263 published in Weather 63:8 please follow link below to view the original article.

Original Article
An EDXRF method for determination of uranium and thorium in AHWR fuel after dissolution
Authors: Dhara Sangita , Kumar S. Sanjay , Misra N. L. , Aggarwal Suresh K.
Published: January 2009

A fast energy dispersive x‐ray fluorescence (EDXRF) method requiring only microgram amounts of analytes, i.e. uranium (U) and thorium (Th), in their mixtures in solution form is described. Calibration solutions and samples covering the fuel composition range (0–5% of U in U + Th) of advanced heavy water reactor (AHWR) were prepared by mixing uranium and thorium solutions. A known fixed amount of internal standard yttrium (Y) was added to these solutions. EDXRF spectra of calibration solutions and samples were measured by taking 20 µl aliquots on 30 mm diameter filter papers, after drying, using a Rh target tube operated at 40 kV and 500 µA. Calibration plots were made by plotting U/Y, U/Th and Th/Y amount ratios against the respective intensity ratios of Th Lα, U Lα and Y Kα. In the first set, U was determined using Y as an internal standard, and for Th determination, U, thus determined, was used as an internal standard since the amounts of Th and Y were kept constant in the calibration solutions and samples.

In the second set, both U and Th were varied and determined using Y as internal standard. The results of U and Th determinations showed a precision of about 3% (1s) and the results deviated from the expected values by <3% in most of the cases. This approach has an advantage that it requires only microgram amounts of sample, thus mitigating radiation hazards associated with radioactive samples as well as the amount of radioactive analytical waste generated is quite less. Copyright © 2009 John Wiley & Sons, Ltd.
New Mixed‐Metal Carbonyl Complexes Containing Bridging 2‐Mercapto‐1‐methylimidazole Ligand
Authors: Ghosh Shishir , Kabir Shariff E. , Pervin Salina , Hossain G. M. Golzar , Haworth Daniel T. , Lindeman Sergey V. , Siddiquee Tasneem A. , Bennett Dennis W. , Roesky Herbert W.
Published: December 2008

Reaction of [Mn2(CO)10] with 2‐mercapto‐1‐methylimidazole in the presence of Me3NO at 25 °C afforded two new dimanganese complexes [Mn2(CO)6(μ‐SN2C4H5)2] (1) and [Mn2(CO)7(μ‐SN2C4H5)2] (2). Compound 1 consists of two μ‐SN2C4H5 ligands, each bound through the sulfur atom to two Mn atoms and through the nitrogen atom to one Mn atom forming a four‐membered chelate ring. Compound 2 was found to consist of one μ‐SN2C4H5 ligand in a similar bonding mode to 1 but another μ‐SN2C4H5 ligand coordinates through the sulfur atom to one Mn atom and through the nitrogen atom to another Mn atom. Compound 1 was also obtained as the only product from the reaction of [Mn2(CO)8(NCMe)2] with 2‐mercapto‐1‐methylimidazole. In contrast, a similar reaction of [Re2(CO)8(NCMe)2] with 2‐mercapto‐1‐methylimidazole led to the formation of the di‐, tri‐, and tetranuclear complexes [Re3(CO)8(μ‐CO)(μ3‐SN2C4H5)2(μ‐H)] (3), [Re4(CO)12(μ‐SN2C4H5)4] (4), and [Re2(CO)6(μ‐SN2C4H5)2] (5). Compound 3 provides a unique example of a hydrido trirhenium compound. The reaction of [Cr(CO)3(NCMe)3] and [Mo(CO)3(NCMe)3] with 1 in refluxing THF afforded the mixed metal complexes [CrMn2(CO)8(μ‐CO)2(μ3‐SN2C4H5)2] (6) and [MoMn2(CO)8(μ‐CO)2(μ3‐SN2C4H5)2] (7), respectively, in which two Mn–M (M = Mo, Cr) bonds were formed. In contrast, a similar treatment of [W(CO)3(NCMe)3] with 1 yielded two W‐Mn complexes [Mn2W(CO)8(μ‐CO)2(μ3‐SN2C4H5)2] (8) and [Mn2W(CO)7(μ‐CO)2(SN2C4H5)(μ3‐SN2C4H5)2] (9). Treatment of 1 with [Fe3(CO)12] at 70‐75 °C afforded the trinuclear mixed‐metal complex [FeMn2(CO)8(μ‐CO)(μ3‐SN2C4H5)2] (10) and the diiron side product [Fe2(CO)6(μ‐S2N2C4H5)2] (11). Compounds 6‐10 have a bent open structure of three metal atoms linked by two metal‐metal bonds and all, except 9 and 10, contain a noncrystallographic two‐fold axis of symmetry. Compound 9 is structurally similar to 8, but it contains a SN2C4H6 ligand, mono coordinated through the exocyclic sulfur atom to the W atom and a Mn–Mn bond instead of a Mn–W bond. Compound 11 comprises two bridging S2N2C4H5 ligands, which arise from the coupling of 2‐mercapto‐1‐methylimidazole with sulfur.
Temperature Influence on the Formation of Selenidoantimonates: Solvothermal Syntheses, Crystal Structures and Thermal Properties of [Ni(dien)2]2Sb2Se6, [Mn(dien)2]2(SbSe4)(Cl), [Co(dien)2]2(SbSe4)(Br), and [Co(dien)2]3(SbSe4)2
Authors: Jin Qin‐yan , Zhu Ai‐mei , Pan Ying‐li , Jia Ding‐xian , Zhang Yong , Gu Jian‐sheng
Published: December 2008

New selenidoantimonats [Ni(dien)2]2Sb2Se6 (1), [Mn(dien)2]2(SbSe4)(Cl) (2), [Co(dien)2]2(SbSe4)(Br) (3), and [Co(dien)2]3(SbSe4)2 (4) (dien = diethylenetriamine) were solvothermally synthesized in dien solvent at 180 °C. The crystal structure of 1 consists of two octahedral [Ni(dien)2]2+ cations and a mixed‐valent [Sb2Se6]4− anion. The isolated [Sb2Se6]4− anion is formed by a SbIIISe3 trigonal pyramid and a SbVSe4 tetrahedron sharing a common corner. 2 and 3 are composed of octahedral [M(dien)2]2+ cations, tetrahedral [SbSe4]3− anions and halide ions forming an extended network through hydrogen‐bonding interactions. In 4 the [Co(1)(dien)2]2+, [Co(2)(dien)2]2+ and [SbSe4]3− ions form layered structures via N–H···Se hydrogen bonds. The [Co(3)(dien)2]2+ ion is located between the layers, and interacts with the layers by N–H···Se bonds. The synthesis and solid state structural studies on the title compounds show that the higher reaction temperature is helpful for the formation of selenidoantimonate(V) compounds in the synthesis of selenidoantimonate from the M2+/Sb/Se/dien system. 1–4 start to decompose at temperature about 210 °C in N2 atmosphere. They lose dien ligands at a wide temperature range of 210–450 °C with multisteps for 1–3 and a single step for 4.
New Examples of Metal Coordination Architectures of 3,3′,4,4′‐Biphenyltetracarboxylic Acid – Syntheses, Crystal Structures, and Physical Properties
Authors: Liu Guang‐Xiang , Zhu Kun , Chen Hong , Huang Rong‐Yi , Ren Xiao‐Ming
Published: December 2008

Four new metal‐organic frameworks [Cu2(2,2′‐bipy)2(ox)(H2O)2]·(H2bptc) (1), [Cu(bptc)0.5(phen)(H2O)]·H2O (2), Co2(bptc)(bmb)1.5 (3) and [Cd2(bptc) (bmb)]·3H2O (4) (H4bptc = 3,3′,4,4′‐biphenyltetracarboxylic acid, ox = oxalate, phen = 1,10‐phenanthroline, 2,2′‐bipy = 2,2′‐bipyridine and bmb = 4,4′‐bis((1H‐imidazol‐1‐yl)methyl)biphenyl), were obtained by reactions of the corresponding metal salts with H4bptc and N‐containing auxiliary ligands and their structures were determined by single‐crystal X‐ray diffraction. The results reveal that 1 has a 0‐D structure consisting of discrete ionic entities, while 2 features a 1‐D ladder structure. Additionally, there exist π‐π stacking and intermolecular hydrogen‐bonding interactions in 1 and 2, respectively, forming 3‐D supramolecular structures. In 3‐4, undulating 2‐D metal‐bptc layer structures are formed with two different coordination modes of bptc carboxylate groups, respectively, which are further extended by bmb into 3‐D structures. Magnetic properties of 1 and 3 have been studied. The photoluminescence property of 4 has also been investigated. Moreover, nonlinear optical measurements showed that 4 displayed a second‐harmonic‐generation (SHG) response of 0.7 times of that for urea.
Substituted Bisphosphanylamines as Ligands in Gold(I) Chemistry – Synthesis and Structures
Authors: Wiedemann Dennis , Gamer Michael T. , Roesky Peter W.
Published: December 2008

Dimethyl 5‐aminoisophthalate, which is a building block of amino‐substituted tetralactam macrocycles, was used as ligand in gold(I) chemistry to form model complexes for macrocyclic gold compounds. Reaction of dimethyl 5‐aminoisophthalate with chlorodiphenylphosphine gave the diphosphine compound dimethyl 5‐[N,N‐bis(diphenylphosphanyl)amino]isophthalate (dmbpaip). This compound can further be reacted with [AuCl(tht)] (tht = tetrahydrothiophene) to give the dinuclear complex [Au2Cl2(dmbpaip)]. In contrast, treatment of dmbpaip with [Au(tht)2]ClO4 resulted in the ionic compound [Au2(dmbpaip)2](ClO4)2 in which the cation forms an eight‐membered Au2P4N2 heterocycle. In both gold(I) compounds Au···Au interactions are observed. All new compounds were characterized by single‐crystal X‐ray diffraction.
The Structures of CrF5 and CrF5·SbF5
Authors: Shorafa Hashem , Seppelt Konrad
Published: December 2008

CrF5 is in the solid a symmetrically cis‐fluorine bridged polymer with close to octahedral coordination at the chromium atom (a = 782.9(2), b = 753.4(2), c = 551.8(1) pm, space group Pbcm, Z = 4). In presence of SbF5 the adduct CrF5·SbF5 is formed. This is also a fluorine bridged polymer with alternating octahedral CrF6 and SbF6 units. (a = 555.2(2), b = 1026.5(3), c = 1198.6(4) pm, β = 99.475(7)°, space group P21/c, Z = 4. The fluorine bridges here are cis on Cr and trans on Sb. The fluorine bridges are highly asymmetric, which allow a description of the compound also as CrF4+SbF6−.
Characterization of Tin(IV) Oxide Thin Films Prepared by Atmospheric Pressure Chemical Vapor Deposition of cis‐[SnCl4{OC(H)OC2H5}2]
Authors: Talaty Nari N. , Beck Kristina , Citeau Helene , Kirschbaum Kristin , Giolando Dean M.
Published: December 2008

A new single‐source precursor, [SnCl4{OC(H)OC2H5}2], prepared by treating tin tetrachloride with ethyl formate (1:2 ratio) was developed for the deposition of tin oxide thin films on glass substrates. The compound [SnCl4{OC(H)OC2H5}2] is highly volatile and provides very high growth rates (up to 100Å s−1 at 560 °C) in an atmospheric pressure chemical vapor deposition (APCVD) reactor. More significantly, the compound does not decompose to tin oxide below 320 °C, thereby minimizing the formation of particles in the vapor above the growing tin oxide film. To prepare highly conducting fluorine doped tin oxide (SnO2:F) films 2,2,2‐trifluoroethyl trifluoroacetate was used as the source of fluoride. High quality SnO2:F films were deposited at 560 °C with a flow rate of 2 mL fluoride reagent hr−1; typical film properties are resistivity of 5.9 X 10−4 Ω cm, Hall mobility of 27.3 cm2 V−1 s−1, carrier concentration of 3.9 X 1020 cm−3 and percent transmission ranging from 86 to 88 %. The best films of SnO2:F possess transparencies as high as 90 % (750 nm), sheet resistances as low as 7 Ω sq−1 and Haacke's figure of merit as high as 29 X 10−3 (750 nm). The newly developed APCVD reactor and the chemistry were optimized with respect to structural, electrical and optical properties of the films by adjusting the substrate temperature, gas flow rates and the amount of fluoride present in the vapor stream. Growth rates with respect to deposition time, substrate temperature and flow rates of precursors were found to be similar for both undoped (SnO2) and doped (SnO2:F) samples. The SnO2:F films possess larger grains than the SnO2 which may account for the lower resistivity and the higher mobility in the SnO2:F samples.
Synthesis and Crystal Structure of KSc(HPO4)2
Authors: Menezes Prashanth W. , Hoffmann Stefan , Prots Yurii , Kniep Rüdiger
Published: December 2008

KSc(HPO4)2 was obtained by hydrothermal synthesis. The crystal structure was determined from single‐crystal X‐ray data: orthorhombic, space group Pnma (No. 62), a = 14.5095(10), b = 5.4260(4), c = 8.4882(5) Å, V = 668.26(8) Å3 and Z = 4. The crystal structure of KSc(HPO4)2 represents a new structure type containing twelve‐ and four‐membered rings forming channels along [010] built of alternating ScO6 octahedra and HPO42− groups. Potassium ions reside within the twelve membered ring channels.
Catalytic Induced Thermal Conversion of Amorphous Carbon into Single Walled Carbon Nanotubes
Authors: Schneider J. J.
Published: December 2008

Figure 1 has to be replaced by the correct Figure
An Old Reaction with New Results: The Unexpected Formation of a Rare Earth Metal Cluster Containing Six Europium Atoms
Authors: Täuscher Eric , Beckert Rainer , Weiß Dieter , Görls Helmar , Birckner Eckhardt
Published: December 2008

Employing a standard protocol for the preparation of a trisbenzoylacetonato europium(III) complex with 4‐bromo benzoylacetone 2 as ligand, a new europium species was synthesized and characterized. The X‐ray crystal structure analysis revealed a new europium cluster consisting of six europiumcentres.
Structure of Plastic Crystalline Succinonitrile: High‐Resolution in situ Powder Diffraction
Authors: Hore Sarmimala , Dinnebier Robert , Wen Wen , Hanson Johnathan , Maier Joachim
Published: December 2008

The temperature dependent (150–290 K) crystal structure of the low‐temperature α‐phase, and high temperature β‐phase, of succinonitrile has been determined by high resolution in situ powder diffraction. The α‐phase has a monoclinic unit cell that contains four gauche molecules and belongs to the P21/a space group. The crystal undergoes a reversible first‐order phase transition at 233 K into the high temperature β‐phase. The lattice parameters increase with temperature and the phase transition leads to an abrupt 6.7 % increase in volume. The β‐phase crystallizes into a bcc‐structure that belongs to the $Im{\bar 3}m$ space group. The high temperature phase; however, is a highly disordered plastic crystal at room temperature that contains both gauche and trans molecules. The non‐linearity in the overall isotropic temperature‐factor indicates other possible phase transitions in the temperature range of 233–250 K.
Profile of Breast Cancer in a Group of Women in a Developing Country in South Asia: Is There a Difference?
Authors: Lokuhetty Menaka D. S. , Ranaweera Gayani G. , Wijeratne Manarangi D. M. , Wickramasinghe Kumudu H. , Sheriffdeen Abdul H.
Published: January 2009

Background

Breast cancer is the commonest cancer among Sri Lankan women. The aim of this study was to document the breast cancer profile of a group of Sri Lankan women and compare it with regional data. Patient‐tumor characteristics and predicted prognosis are compared with the immune profile.

Methods

A total of 814 Sri Lankan women with breast cancer were studied, with their information retrieved from patient records. Tumor type and grade were reassessed on routine tissue sections. The Nottingham Prognostic Index (NPI) was calculated. Estrogen receptors (ER) and human epidermal receptor 2 (HER2) were assessed using Dako antibodies. Strong nuclear staining for ER in >10% of tumor cells and strong, complete cell membrane staining (3+) for HER2 were regarded as positive. An SPSS‐16 software program and the chi‐squared test were used for statistical analysis.

Results

The highest prevalence (32%) was in the 50‐ to 59‐year age cohort (mean ± SD 51.88 ± 11.939 years). In all, 58% of the tumors measured between 2 and 5 cm. Most (52%) were moderately differentiated and were invasive ductal carcinomas (86.3%). Regional lymph node metastasis was present in 41% of the patients. ER was expressed in 31.7% and was more frequent in women >35 years (p < 0.024). HER2 was found in 14.5% of tumors. Its expression was lower in ER‐positive tumors (p < 0.000). Well‐differentiated tumors were frequently ER‐positive (p < 0.000) and HER2‐negative (p < 0.001). The NPI was better for ER‐positive (p < 0.000) and HER2‐negative tumors (p < 0.028).

Conclusions

The overall profile of breast cancer and immune characteristics of Sri Lankan women in this study was largely comparable to profiles documented elsewhere in the region despite the lower prevalence of ER.
Laparoscopic Surgical Skills Assessment: Can Simulators Replace Experts?
Authors: Pellen Michael , Horgan Liam , Roger Barton J. , Attwood Stephen
Published: January 2009

Introduction

Global Rating Scales (GRS) quantify and structure subjective expert assessment of skill. Hybrid simulators measure performance during physical laparoscopic tasks through instrument motion analysis. We assessed whether motion analysis metrics were as accurate as structured expert opinion by using GRS.

Methods

A random sample of 10 consultant laparoscopic surgeons, 10 senior trainees, and 10 novice students were assessed on a Sharp Dissection task. Coded video footage was reviewed by two blinded assessors and scored using a Likert Scale. Correlation with metrics was tested using Spearman’s rho. Inter‐rater reliability was measured using intraclass correlation coefficient (ICC).

Results

Strongest GRS–Metric correlations were found for Time/Motion/Progress with Time (Spearman’s rho 0.88; p < 0.05) and Instrument Handling with Path Length (Spearman’s rho 0.8; p < 0.05). Smoothness correlated with Respect for Tissue in Rater 1 (rho 0.68) but not Rater 2 (rho 0.18). Mean GRS showed stronger inter‐rater agreement than individual scale components (ICC 0.68). Correlation coefficients with actual experience group were 0.58–0.74 for mean GRS score and 0.67–0.78 for metrics (Spearman’s rho, p < 0.05).

Conclusions

Metrics correlate well with GRS assessment, supporting concurrent validity. Metrics predict experience level as accurately as global rating and are construct valid. Hybrid simulators could provide resource‐efficient feedback, freeing trainers to concentrate on teaching.
Single Port Access Laparoscopic Cholecystectomy (with video)
Authors: Bucher Pascal , Pugin François , Buchs Nicolas , Ostermann Sandrine , Charara Fadi , Morel Philippe
Published: January 2009

Background

Single port access (SPA) surgery is a rapidly evolving field due to the complexity of NOTES (natural orifice translumenal endoscopic surgery). SPA combines the cosmetic advantage of NOTES and possibility to perform surgical procedure with standard laparoscopic instruments. We report a technique of umbilical SPA cholecystectomy using standard laparoscopic instruments and complying with conventional surgical principle and technique of minimally invasive cholecystectomy.

Methods

Preliminary, prospective experience of SPA cholecystectomy in 11 patients (median age, 46 (range, 27–63) years) scheduled for cholecystectomy was evaluated. Diagnoses for cholecystectomy were: symptomatic gallbladder lithiasis (n = 7), previous acute cholecystitis (n = 3), and biliary pancreatitis (n = 1).

Results

SPA cholecystectomy was feasible in all patients (median body mass index, 24 (range, 20–34) kg/m2) who were scheduled for preliminary experience using conventional laparoscopic instruments. Median operative time was 52 (range, 40–77) minutes. Intraoperative cholangiography was performed in all patients, except one, and was considered normal. No peroperative or postoperative complications were recorded. Median hospital stay was less than 24 h.

Conclusions

SPA cholecystectomy is feasible and seems to be safe when performed by experienced laparoscopic surgeons using standard laparoscopic instrumentation. SPA cholecystectomy may be safer than the NOTES approach at this time. It has to be determined whether this approach would benefit patients, other than cosmesis, compared with standard laparoscopic cholecystectomy.
Prospective treatment of cerebrotendinous xanthomatosis with cholic acid therapy
Authors: Pierre Germaine , Setchell Kenneth , Blyth Jacqueline , Preece Mary Anne , Chakrapani Anupam , McKiernan Patrick
Published: January 2009

Cerebrotendinous xanthomatosis (CTX) OMIM#213700 is a rare disorder of bile acid synthesis caused by deficiency of the enzyme sterol 27‐hydroxylase. It results in deficiency of bile acids and accumulation of abnormal bile alcohols and accelerated cholesterol synthesis. CTX usually presents in the second or third decade with slowly progressive neurological dysfunction, cerebellar ataxia and premature atherosclerosis. Treatment with bile acid supplementation improves but does not completely reverse the neurological signs and symptoms. However, CTX is now known to be associated with a period of neonatal cholestasis. If it is diagnosed at this point, treatment may prevent the onset of neurological problems. We present the case histories and developmental findings in two affected siblings treated from infancy. We plan to continue regular neurodevelopmental reviews.
An Innovative Modular Approach in an Automated Compact Immunoassay System
Authors: Truchaud A. , Bois E. , Ferre A. , Morin D. , Chevelder J.C. , Colombier G. , Capolaghi B. , Zingler C. , Orsonneau J.L. , Masson D. , Miraille S.
Published: December 2008

The KRYPTOR compact (CEZANNE SAS) is an innovative automated immunoassay system using a homogeneous technology avoiding separation and washing steps. The main innovation of the KRYPTOR compact is the modular design of the instrument including two separable parts: a pipeting module and a reading module. The transportable reagents cassette includes an original cooling system activated when it is on board. The system is selfchecking, reagents are precalibrated with only two points of verification by the user, fast and easy to maintain. A first multisites evaluation of the analytical performances and practicability proved the ability of this system to answer well to laboratories that demand special parameters with a medium or smaller throughput such as urgent requests or highly specialized activities.