bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Class of Organosuperbases, N‐Alkyl‐ and N‐Aryl‐1,3‐dialkyl‐4,5‐dimethylimidazol‐2‐ylidene Amines: Synthesis, Structure, pKBH+ Measurements, and Properties
Authors: Kunetskiy Roman A. , Polyakova Svetlana M. , Vavřík Jiří , Císařová Ivana , Saame Jaan , Nerut Eva Roos , Koppel Ivar , Koppel Ilmar A. , Kütt Agnes , Leito Ivo , Lyapkalo Ilya M. 
Published: February 2012

AbstractA series of stable organosuperbases, N‐alkyl‐ and N‐aryl‐1,3‐dialkyl‐4,5‐dimethylimidazol‐2‐ylidene amines, were efficiently synthesized from N,N′‐dialkylthioureas and 3‐hydroxy‐2‐butanone and their basicities were measured in acetonitrile. The derivatives with tert‐alkyl groups on the imino nitrogen were found to be more basic than the tBuP1(pyrr) phosphazene base in acetonitrile. The origin of the high basicity of these compounds is discussed. In acetonitrile and in the gas phase, the basicity of the alkylimino derivatives depends on the size of the substituent at the imino group, which influences the degree of aromatization of the imidazole ring, as measured by 13C NMR chemical shifts or by the calculated ΔNICS(1) aromaticity parameters, as well as on solvation effects. If a wider range of imino‐substituents, including electron‐acceptor substituents, is treated in the analysis then the influence of aromatization is less predominant and the gas‐phase basicity becomes more dependent on the field‐inductive effect, polarizability, and resonance effects of the substituent.
Stereoselective Access to Fluorinated and Non‐fluorinated Quaternary Piperidines: Synthesis of Pipecolic Acid and Iminosugar Derivatives
Authors: Fustero Santos , Albert Laia , Mateu Natalia , Chiva Gema , Miró Javier , González Javier , Aceña José Luis 
Published: February 2012

AbstractThe preparation of optically pure quaternary piperidines, both fluorinated and non‐fluorinated, has been achieved from a chiral imino lactone derived from (R)‐phenylglycinol. In the case of the fluorinated derivatives, the addition of (trifluoromethyl)trimethylsilane (TMSCF3) followed by iodoamination and migration of the CF3 group allowed access to four derivatives of α‐(trifluoromethyl)pipecolic acid. A theoretical study of the CF3‐group rearrangement has been carried out to help establish the reaction mechanism of this uncommon transformation. Moreover, a route to trifluoromethyl‐substituted iminosugars was also developed through the diastereoselective dihydroxylation of suitable synthetic intermediates. Conversely, alkylation of the starting substrate and subsequent cross‐metathesis and aza‐Michael reactions led to α‐alkyl derivatives of the target compounds.
Synthesis and Characterization of New Iridium Photosensitizers for Catalytic Hydrogen Generation from Water
Authors: Gärtner Felix , Denurra Stefania , Losse Sebastian , Neubauer Antje , Boddien Albert , Gopinathan Anilkumar , Spannenberg Anke , Junge Henrik , Lochbrunner Stefan , Blug Matthias , Hoch Sascha , Busse Jens , Gladiali Serafino , Beller Matthias 
Published: February 2012

AbstractNovel phenylazole ligands were applied successfully in the synthesis of cyclometalated iridium(III) complexes of the general formula [Ir(phenylazole)2(bpy)]PF6 (bpy=2,2′‐bipyridine). All complexes were fully characterized by NMR, IR, and MS spectroscopic studies as well as by cyclic voltammetry. Three crystal structures obtained by X‐ray analysis complemented the spectroscopic investigations. The excited‐state lifetimes of the iridium complexes were determined and showed to be in the range of several hundred ns to multiple µs. All obtained iridium complexes were active as photosensitizers in catalytic hydrogen evolution from water in the presence of triethylamine as a sacrificial reducing agent. Applying an in situ formed iron‐based water reduction catalyst derived from [HNEt3]+[HFe3(CO)11]− and tris[3,5‐tris‐(trifluoromethyl)‐phenyl]phosphine as the ligand, [Ir(2‐phenylbenz‐oxazole)2‐(bpy)]PF6 proved to be the most efficient complex giving a quantum yield of 16 % at 440 nm light irradiation.
Effect of baffles on fluid flow field in stirred tank with floating particles by using PIV
Authors: Atibeni Rajab , Gao Zhengming , Bao Yuyun 
Published: February 2012

AbstractPIV technique was applied to elucidate the effect of baffles at different shaft positions and different impeller off‐bottom clearances on the flow field in a stirred tank with floating particles. The investigation was carried out in a cylindrical tank with a flat base, and five different baffle configurations: standard baffles, narrow baffles with a width of 15 mm, narrow baffles with a width of 10 mm, down triangular baffles and up triangular baffles. The measurements show that down triangular baffles offers several advantages over standard baffles at C = T/3: high axial and radial velocities, relatively Low critical agitation speed and power consumption for just drawdown of 1.0 vol.% floating particles. While at C = T/2 this superiority disappears and the fluid flow field is similar to that for standard baffles. The other baffles are similar in performance except for a small difference in the critical agitation speed. An off‐centred shaft helps reduce the critical just drawdown speed and the corresponding power consumption for baffle configurations considered. With down triangular baffles, the critical power consumption to draw down the floating particles for the most eccentric shaft is about 42% of that for a centred shaft. © 2012 Canadian Society for Chemical Engineering
Characterisation of biocatalysts immobilised in niobium—a new inorganic solid support
Authors: Aguiar‐Oliveira E. , Fernandes P. , Cabral J. M. S. , Maugeri F. 
Published: February 2012

AbstractA new support for enzyme immobilisation, an alloy of niobium ore and graphite, was tested with: invertase from baker's yeast and inulinase from Aspergillus niger. The efficiency of immobilisation was about 30% for invertase and 72% for inulinase. The maximum activities values were observed for both enzymes at: pH 4.5, 50°C and 500 g/L of sucrose. The hydrolysis of inulin (5% w/v) by the free inulinase and invertase presented specific productivity of reducing sugars lower after immobilisation, about 15 and 1.5 times, respectively; with the hydrolysis of sucrose (50% w/v) the reductions observed were of 14 and 3.5 times, respectively. © 2012 Canadian Society for Chemical Engineering
Bounded influence nonlinear signed‐rank regression
Authors: Bindele Huybrechts F. , Abebe Asheber 
Published: February 2012

AbstractIn this paper we consider weighted generalized‐signed‐rank estimators of nonlinear regression coefficients. The generalization allows us to include popular estimators such as the least squares and least absolute deviations estimators but by itself does not give bounded influence estimators. Adding weights results in estimators with bounded influence function. We establish conditions needed for the consistency and asymptotic normality of the proposed estimator and discuss how weight functions can be chosen to achieve bounded influence function of the estimator. Real life examples and Monte Carlo simulation experiments demonstrate the robustness and efficiency of the proposed estimator. An example shows that the weighted signed‐rank estimator can be useful to detect outliers in nonlinear regression.The Canadian Journal of Statistics40: 172–189; 2012 © 2012 Statistical Society of Canada
Constrained penalized splines
Authors: Meyer Mary C. 
Published: February 2012

AbstractThe penalized spline is a popular method for function estimation when the assumption of “smoothness” is valid. In this paper, methods for estimation and inference are proposed using penalized splines under additional constraints of shape, such as monotonicity or convexity. The constrained penalized spline estimator is shown to have the same convergence rates as the corresponding unconstrained penalized spline, although in practice the squared error loss is typically smaller for the constrained versions. The penalty parameter may be chosen with generalized cross‐validation, which also provides a method for determining if the shape restrictions hold. The method is not a formal hypothesis test, but is shown to have nice large‐sample properties, and simulations show that it compares well with existing tests for monotonicity. Extensions to the partial linear model, the generalized regression model, and the varying coefficient model are given, and examples demonstrate the utility of the methods.The Canadian Journal of Statistics40: 190–206; 2012 © 2012 Statistical Society of Canada
Duration analysis in longitudinal studies with intermittent observation times and losses to followup
Authors: Hajducek D. M. , Lawless J. F. 
Published: February 2012

AbstractWe consider the analysis of spell durations observed in event history studies where members of the study panel are seen intermittently. Challenges for analysis arise because losses to followup are frequently related to previous event history, and spells typically overlap more than one observation period. We provide methods of estimation based on inverse probability of censoring weighting for parametric and semiparametric Cox regression models. Selection of panel members through a complex survey design is also addressed, and the methods are illustrated in an analysis of jobless spell durations based on data from the Statistics Canada Survey of Labour and Income Dynamics. The Canadian Journal of Statistics 40: 1–21; 2012 © 2012 Statistical Society of Canada
Constrained nonparametric maximum likelihood estimation of stochastically ordered survivor functions
Authors: Park Yongseok , Kalbfleisch John D. , Taylor Jeremy M. G. 
Published: February 2012

AbstractThis paper considers estimators of survivor functions subject to a stochastic ordering constraint based on right censored data. We present the constrained nonparametric maximum likelihood estimator (C‐NPMLE) of the survivor functions in one‐and two‐sample settings where the survivor distributions could be discrete or continuous and discuss the non‐uniqueness of the estimators. We also present a computationally efficient algorithm to obtain the C‐NPMLE. To address the possibility of non‐uniqueness of the C‐NPMLE of $S_1(t)$ when $S_1(t)\le S_2(t)$, we consider the maximum C‐NPMLE (MC‐NPMLE) of $S_1(t)$. In the one‐sample case with arbitrary upper bound survivor function $S_2(t)$, we present a novel and efficient algorithm for finding the MC‐NPMLE of $S_1(t)$. Dykstra (1982) also considered constrained nonparametric maximum likelihood estimation for such problems, however, as we show, Dykstra's method has an error and does not always give the C‐NPMLE. We corrected this error and simulation shows improvement in efficiency compared to Dykstra's estimator. Confidence intervals based on bootstrap methods are proposed and consistency of the estimators is proved. Data from a study on larynx cancer are analysed to illustrate the method. The Canadian Journal of Statistics 40: 22–39; 2012 © 2012 Statistical Society of Canada
Do Gender Differences in Depression Remain after Controlling for Early Maladaptive Schemas? An Examination in a Sample of Opioid Dependent Treatment Seeking Adults
Authors: Shorey Ryan C. , Stuart Gregory L. , Anderson Scott 
Published: February 2012

The abuse of opioids is a serious and prevalent problem and research is needed on factors that may place individuals at risk for misusing opioids. Depression is a common co‐morbid mental health problem among opioid users. Theory and research suggest that early maladaptive schemas may underlie mental health problems including depression and substance abuse. The current study sought to determine whether early maladaptive schemas were associated with depression among a treatment seeking sample of male and female opioid users (n = 194). We also examined whether depression, as assessed by the Minnesota Multiphasic Personality Inventory, Second Edition, varied by gender and whether gender differences in depression remained after controlling for early maladaptive schemas. Results showed that women scored significantly higher than men on three of the five early maladaptive schema domains and that gender did not predict depression after controlling for schema domains. Early maladaptive schemas were also more strongly associated with depression for men than women. Implications of these findings for interventions and future research are discussed. Copyright © 2012 John Wiley & Sons, Ltd.Key Practicioner Message

Individuals with opioid dependence have a number of early maladaptive schemas that may be contributing to the onset and maintenance of substance use.
Although there are generally broad gender differences in major depression, findings from the current study suggest that early maladaptive schemas are a better predictor of depressive symptoms than gender among opioid dependent adults.
The treatment of opioid dependence, with or without co‐morbid depressive symptoms, should target early maladaptive schemas.
Do allopatric maleCalopteryx virgodamselflies learn species recognition?
Authors: Kuitunen Katja , Haukilehto Elina , Raatikainen Kaisa J. , Hakkarainen Hanne , Miettinen Minna , Högmander Harri , Kotiaho Janne S. 
Published: February 2012

AbstractThere is a growing amount of empirical evidence that premating reproductive isolation of two closely related species can be reinforced by natural selection arising from avoidance of maladaptive hybridization. However, as an alternative for this popular reinforcement theory, it has been suggested that learning to prefer conspecifics or to discriminate heterospecifics could cause a similar pattern of reinforced premating isolation, but this possibility is much less studied. Here, we report results of a field experiment in which we examined (i) whether allopatricCalopteryx virgodamselfly males that have not encountered heterospecific females of the congenerC. splendensinitially show discrimination, and (ii) whetherC. virgomales learn to discriminate heterospecifics or learn to associate with conspecifics during repeated experimental presentation of females. Our experiment revealed that there was a statistically nonsignificant tendency forC. virgomales to show initial discrimination against heterospecific females but because we did not use sexually naïve individuals in our experiment, we were not able to separate the effect of innate or associative learning. More importantly, however, our study revealed that species discrimination might be further strengthened by learning, especially so thatC. virgomales increase their association with conspecific females during repeated presentation trials. The role of learning to discriminateC. splendensfemales was less clear. We conclude that learning might play a role in species recognition also when individuals are not naïve but have already encountered potential conspecific mates.
Preparation of Diamine‐β‐diketiminato Copper(II) Complexes and Their Application in the Reverse Atom‐Transfer Radical Polymerization of Styrene
Authors: Champouret Yohan , Gulli Stefano , Daran Jean‐Claude , Poli Rinaldo 
Published: February 2012

AbstractCompound Et2NCH2CH2N=C(Me)CH=C(Me)NHCH2CH2NEt2 (HL), after conversion to the Li+ salt with use of MeLi, reacts with CuCl2 in toluene to yield CuClL (1). The compound adopts a four‐coordinate CuClN3 environment with a pendant amino arm. The same reaction with CuCl and[Cu(MeCN)4]BF4 leads to disproportionation with deposition of metallic copper. Crystals of compounds [CuL][CuCl2] (2) and [CuL]BF4 (3) were isolated in minor amounts from these reactions. The [CuL]+ ion in these compounds has a four‐coordinate CuN4 environment. Compound 2 was also obtained in good yields from the reaction between equivalent amounts of 1 and CuCl. Compound 1 was used to control the radical polymerization of styrene under ARGET ATRP conditions in the presence of glucose as reducing agent and bromoethylbenzene as initiator. The polymerization behavior indicates that the controlling ability of this system is negatively affected by its slow trapping rate and by the disproportionation of the CuL catalyst.
Kinetic and Mechanistic Studies on the Reactions of the Reduced Vitamin B12 Complex Cob(I)alamin with Nitrite and Nitrate (Eur. J. Inorg. Chem. 6/2012)
Authors: Plymale Noah T. , Dassanayake Rohan S. , Hassanin Hanaa A. , Brasch Nicola E. 
Published: February 2012

AbstractThe cover picture shows that nitrate and especially nitrite rapidly oxidize cob(I)alamin to cob(II)alamin. Enzyme‐bound cob(I)alamin is a short‐lived species whose formation is essential for the activity of both mammalian vitamin B12 dependent enzymes. Nitrite and nitrate, intracellular levels of which are elevated during oxidative/nitrosative stress as a consequence of elevated nitric oxide levels, are generally considered to be benign species. Details are discussed in the article by N. E. Brasch et al. on p. 913 ff. The cover picture was designed by Rohan S. Dassanayake. magnified image
A critical body residue approach for predicting persistent bioaccumulative toxicant effects on reproduction and population dynamics of meiobenthic copepods
Authors: Chandler G. Thomas , Ferguson P. Lee , Klauber W.W. , Washburn K.M. 
Published: February 2012

Abstract
Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose–response on a dry-weight or lipid-normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E-2317-14) produced biomass sufficient for dry mass and lipid-normalized CBR estimates of reproduction (fertility) and population growth suppression. Significant FS toxic effects were delayed naupliar development (at ≥0.10 µg L−1), delayed copepodite development (at 0.85 µg L−1), decreased reproductive success (at ≥ 0.39 µg L−1), and decreased offspring production (at 0.85 µg L−1). A reproductive median effective concentration (EC50) of 0.16 µg L−1 (95% CI: 0.12–0.21 µg L−1) corresponded to an adult all-sex CBR and lipid-normalized CBR of 0.38 pg FS · µg−1 dry weight (95% CI: 0.27–0.52 pg FS · µg−1) or 2.8 pg FS · µg−1 lipid (95% CI: 2.2–3.6 pg FS · µg−1), respectively. Copepod log bioconcentration factor (BCF) = 4.11 ± 0.2. Leslie matrix projections regressed against internal dose predicted fewer than five gravid females in a population by the third generation at 0.39 and 0.85 µg FS · L−1 (i.e., 9.6–10.2 µg FS · µg−1 lipid), and 50% population suppression at a CBR of 1.6 pg FS · µg−1 lipid. This more integrative population CBR as a management tool would fall 1.75 times below the CBR for the single most sensitive endpoint—fertility rate. Environ. Toxicol. Chem. 2012; 31: 1076–1082. © 2012 SETAC
Assessment of aquatic wastewater pollution in a highly industrialized zone with sediment linear alkylbenzenes
Authors: Zhang Kai , Wang Ji-Zhong , Liang Bo , Shen Ru-Lang , Zeng Eddy Y. 
Published: February 2012

Abstract
Forty-five sediment samples collected from Dongjiang River, which drains one of the most industrialized and urbanized regions in South China, were analyzed for 19 linear alkylbenzene (LAB) components. The sample dry weight–based concentrations of total LABs (ΣLAB) ranged from 1.5 to 410 ng/g. Comparison of the relative abundances of n-dodecylbenzenes (or C12-LABs) and internal to external ratio (I/E) values in riverine sediment, wastewater, and sediment samples from the outfalls of paper mills, as well as three brands of domestic detergents obtained from the present and previous studies, implicated the occurrence of untreated wastewater in the sampling sites. Levels of ΣLAB were significantly linear correlated with those of total organic carbon (TOC) but not with those of polycyclic aromatic hydrocarbons. Multiple linear regression integrated principal component analysis indicated that 56% of LABs in wastewater in the study area were treated, but the extent of degradation of LABs was low. Finally, it is proposed that ineffective law enforcement and loopholes in the current regulations for wastewater discharge account for the substantial amount (44%) of untreated wastewater discharged in the study region. Environ. Toxicol. Chem. 2012;31:724–730. © 2012 SETAC
Reservoir rainfall–runoff geomorphological model. I: application and parameter analysis
Authors: Goñi M. , López J. J. , Gimena F. N. 
Published: February 2012

AbstractThis article describes and formulates a model designed to simulate runoff in wet weather events, called reservoir rainfall–runoff geomorphological model (R3GeM). In these wetlands, soil saturation is the main mechanism for the generation of surface runoff. To determine the saturated areas, the model applies a relationship based on the topographic index, between watershed storage and saturated surface. Precipitation is separated into surface runoff by saturation, subsurface runoff and losses; then, the flow of surface and subsurface runoff is performed. This hydrological model has five parameters and has been implemented in 37 events in Aixola watershed and 15 in Oiartzun watershed, both located on the Cantabrian coast of Spain. We analysed the influence of these five parameters in their behaviour, and we have proven, noting the efficiency gains, that the proposed model is valid to simulate the rainfall–runoff process. Copyright © 2012 John Wiley & Sons, Ltd.
The impact of climate change on sea level rise at Peninsular Malaysia and Sabah–Sarawak
Authors: Ercan Ali , Bin Mohamad Mohd Fauzi , Kavvas M. Levent 
Published: February 2012

AbstractThe sea level change along the Peninsular Malaysia and Sabah–Sarawak coastlines for the 21st century is investigated along the coastal areas of Peninsular Malaysia and Sabah–Sarawak because of the expected climate change during the 21st century. The spatial variation of the sea level change is estimated by assimilating the global mean sea level projections from the Atmosphere–Ocean coupled Global Climate Model/General Circulation Model (AOGCM) simulations to the satellite altimeter observations along the subject coastlines. Using the assimilated AOGCM projections, the sea level around the Peninsular Malaysia coastline is projected to rise with a mean in the range of 0.066 to 0.141 m in 2040 and 0.253 m to 0.517 m in 2100. Using the assimilated AOGCM projections, the sea level around Sabah–Sarawak coastlines is projected to rise with a mean in the range of 0.115 m to 0.291 m in 2040 and 0.432 m to 1.064 m in 2100. The highest sea level rise occurs at the northeast and northwest regions in Peninsular Malaysia and at north and east sectors of Sabah in Sabah–Sarawak coastline. Copyright © 2012 John Wiley & Sons, Ltd.
A storm event watershed model for surface runoff based on 2D fully dynamic wave equations
Authors: Costabile Pierfranco , Costanzo Carmelina , Macchione Francesco 
Published: February 2012

AbstractThe main purpose of this work concerns the development and testing of an overland flow model based on the two‐dimensional fully dynamic shallow water equations. Three key aspects, fundamental to get accurate, efficient and robust computation of surface runoff at basin scale, are discussed by transferring the main findings obtained by the recent research on the topic of dam‐break wave and flood propagation in the context of rainfall–runoff modelling. In particular, attention is focused on the numerical flux and bottom slope source terms computation, on a numerical treatment of friction slope terms and on an algorithm for dealing with wetting/drying fronts. The performances of the numerical model have been preliminarily evaluated using experimental or ideal tests characterized by very critical conditions for the stability of a numerical model. Then, attention was focused on a real event occurred in a sub‐basin of Reno river in Italy to analyse the suitability of the model in simulating real flood situations. The numerical results highlight the good performances of the model in all the simulations discussed in the paper. Copyright © 2012 John Wiley & Sons, Ltd.