bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alkali Metal Thioselenophosphinates, M[SeSPR2]: One‐Pot Multicomponent Synthesis, DFT Study, and Synthetic Application
Authors: Artem'ev Alexander V. , Gusarova Nina K. , Bagryanskaya Irina Yu. , Doronina Evgeniya P. , Verkhoturova Svetlana I. , Sidorkin Valery F. , Trofimov Boris A. 
Published: December 2012

AbstractDiverse alkali metal thioselenophosphinates, M[SeSPR2] (M = Li, Na, K, Rb, and Cs; R = alkyl, aryl, aralkyl, and hetaralkyl), have been synthesized in 78–94 % yields by means of a one‐pot multicomponent reaction between secondary phosphanes, sulfur, selenium, and alkali metal hydroxides under mild conditions (room temperature, –50 °C, 0.5 h, EtOH). The molecular and electronic structure of the [SeSPPh2]– anion and its coordination behavior towards Li+, Na+, and K+ cations have been investigated at the B3LYP level of theory. The alkylation of the alkali metal thioselenophosphinates with various organic halides proceeds regiosecifically at the selenium center to form Se–organyl thioselenophosphinates, R2P(S)SeR′ (R′ = Me, Et, Bn, allyl, propargyl), in 78–96 % yields. By the action of molecular iodine, the alkali metal thioselenophosphinates instantly (room temperature, ca. 1 s, 1,4‐dioxane) undergo selective Se–Se oxidative coupling to afford the corresponding diselenides, R2P(S)SeSe(S)PR2, in 81–92 % yields. The alkali metal thioselenophosphinates are readily converted into the corresponding ammonium derivatives. Square‐planar NiII complexes, Ni[SeSPR2]2 (R = Ph, CH2CH2Ph), have been prepared in 68–81 % yield by the treatment of sodium thioselenophosphinates, Na[SeSPR2], with NiBr2 at room temperature (EtOH/CH2Cl2, 10 min).
Spin Crossover in Iron(III) Complexes with Pentadentate Schiff Base Ligands and Pseudohalido Coligands
Authors: Krüger Christoph , Augustín Peter , Nemec Ivan , Trávníček Zdeňek , Oshio Hiroki , Boča Roman , Renz Franz 
Published: December 2012

AbstractIron(III) mononuclear complexes that involve pentadentate Schiff base ligands and chlorido, azido, cyanido, cyanato, thiocyanato, or selenocyanato coligands were synthesized, structurally characterized, and subjected to a magnetochemical investigation. The Schiff bases were derived either from 5‐chlorosalicylaldehyde or the 2‐hydroxyacetonaphthone analogues by using an asymmetric 1,6‐diamino‐4‐azahexane. A polymorphism that originated from different pentadentate ligand conformations on the iron center or different arrangements of noncovalent contacts was detected for the thiocyanato complexes. The central iron(III) atoms are mostly in the high‐spin states, except for that with the coordinated cyanido ligand. Four complexes that contain the thiocyanato or selenocyanato ligand exhibit spin crossover, centered at the critical temperature (Tc) of 42, 114, 282, and 293 K, respectively. The magnetic data of all compounds were analyzed using the spin Hamiltonian formalism including the zero‐field splitting (ZFS) term, and in the case of the spin‐crossover compounds, the Ising‐like model with vibrations was applied.
Synthesis of 2,6‐Di(pyrazol‐1‐yl)pyrazine Derivatives and the Spin‐State Behavior of Their Iron(II) Complexes
Authors: Mohammed Rufeida , Chastanet Guillaume , Tuna Floriana , Malkin Tamsin L. , Barrett Simon A. , Kilner Colin A. , Létard Jean‐François , Halcrow Malcolm A. 
Published: December 2012

AbstractChlorination of 2,6‐bis(pyrazol‐1‐yl)pyrazine (bppz) with NaClO in acetic acid afforded 2,6‐bis(4‐chloropyrazol‐1‐yl)pyrazine (L2Cl). 2,6‐Bis(4‐bromopyrazol‐1‐yl)pyrazine (L2Br), 2,6‐bis(4‐iodopyrazol‐1‐yl)pyrazine (L2I), 2,6‐bis(4‐methylpyrazol‐1‐yl)pyrazine (L2Me), and 2,6‐bis(4‐nitropyrazol‐1‐yl)pyrazine (L2NO2) were also prepared by reactions of the preformed 4‐substituted pyrazoles with 2,6‐dichloropyrazine. The reduction of L2NO2 with iron powder gave 2,6‐bis(4‐aminopyrazol‐1‐yl)pyrazine (L2NH2) and L2I was converted into 2,6‐bis[4‐(phenylethynyl)pyrazol‐1‐yl]pyrazine (L2CCPh) by a Sonogashira coupling reaction. The salts [Fe(L2Me)2]X2 (X– = BF4– and ClO4–) underwent thermal spin‐crossover abruptly at around 200 K in one and two steps, respectively. The [Fe(L2Me)2]X2 salts exhibited different light‐induced excited spin‐state trapping (LIESST) behavior; the BF4– salt behaves classically [T(LIESST) = 93 K], but the ClO4– salt undergoes a multistep LIESST relaxation. In contrast, solid [Fe(L2Cl)2][BF4]2 adopts a fixed 2:1 high/low‐spin‐state population that does not change with temperature below 300 K, whereas [Fe(L2Br)2][BF4]2 and [Fe(L2I)2][BF4]2 form low‐spin solvated crystals that are transformed into high‐spin powders on drying. The pyrazinyl group in the L2R ligands slightly stabilizes the low‐spin state of the complexes, as determined by solution‐phase magnetic measurements. The crystal structure of [Fe(L2CCPh)(OH2)z][BF4]2 contains a disordered mixture of six‐ (z = 3) and seven‐coordinate (z = 4) iron centers.
Performance evaluation of batch and unsteady state fed‐batch reactor operations for the production of a marine microbial surfactant
Authors: Sivapathasekaran Chandrasekaran , Sen Ramkrishna 
Published: December 2012

AbstractBACKGROUND: Biosurfactants are microbially derived surface‐active and amphipathic molecules produced by various microorganisms. These versatile biomolecules can find potential applications in food, cosmetics, petroleum recovery and biopharmaceutical industries. However, their commercial use is impeded by low yields and productivities in fermentation processes. Thus, an attempt was made to enhance product yield and process productivity by designing a fed‐batch mode reactor strategy.RESULTS: Biosurfactant (BS) production by a marine bacterium was performed in batch and fed‐batch modes of reactor operation in a 3.7 L fermenter. BS concentration of 4.61 ± 0.07 g L−1 was achieved in batch mode after 22 h with minimum power input of 33.87 × 103 W, resulting in maximum mixing efficiency. The volumetric oxygen flow rate (KLa) of the marine culture was about 0.08 s−1. BS production was growth‐associated, as evident from fitting growth kinetics data into the Luedeking‐Piret model. An unsteady state fed batch (USFB) strategy was employed to enhance BS production. Glucose feeding was done at different flow rates ranging from 3.7 mL min−1 (USFB‐I) to 10 mL min−1 (USFB‐II). USFB‐I strategy resulted in a maximum biosurfactant yield of 6.2 g l−1 with an increment of 35% of batch data. The kinetic parameters of USFB‐I were better than those from batch and USFB‐II.CONCLUSION: Comparative performance evaluation of batch and semi‐continuous reactor operations was accomplished. USFB‐I operation improved biosurfactant production by about 35% over batch mode. USFB‐I strategy was more kinetically favorable than batch and USFB‐II. © 2012 Society of Chemical Industry
Modelling of chemical surface acoustic wave sensors and comparative analysis of new sensing materials
Authors: Hribšek Marija F. , Ristić Slavica S. , Radojković Bojana M. , Filipović Zoran Lj. , Ristić Ognjen R. 
Published: December 2012

SUMMARYComparative analysis of different, new gas sensing materials in surface acoustic wave chemical sensors is presented. Different gas sensing materials as polyaniline (PANI), Teflon AF 2400, polyisobutylene (PIB), polyepichlorohydrin (PECH) are considered. They are chosen according to the type of gas to be detected and the desired accuracy: Teflon AF 2400 thin film for the detection of CO2, PANI nanocomposites film that belongs to the group of conductive polymers for the detection of CO, NO2 and phosgene (COCl2), and PECH and PIB for the detection of dichloromethane (CH2Cl2, DCM). In the analysis, the simple and useful method of the complete analyses of gas chemical sensors is used. The method is based on the electrical equivalent circuit of the surface acoustic wave sensor. The method is very efficient and can be used for the optimal design of CO2 sensors. The results are compared with those presented in public literature and good agreement is obtained, demonstrating the validity of modelling. Copyright © 2012 John Wiley & Sons, Ltd.
Quantification of image quality for color electronic paper
Authors: Nose Masaki , Yoshihara Toshiaki 
Published: December 2012

AbstractWe have quantified the image quality of color electronic paper (e‐paper) by subjective evaluations and clarified the requirements for improving the image quality. In the color e‐paper field, various display types have been developed with the focus on improving the display performances or manufacture costs. However, color e‐papers are still under development, and the image quality is not sufficient when compared with printed papers, photographs and conventional displays. With respect to the image quality of color e‐paper in the future, it is very significant to clarify how reflectance, contrast ratio, National Television System Committee (NTSC) ratio, and other factors affect the image quality. Therefore, we have quantified the image quality factors such as color reproduction, tone reproduction, and surface texture. From our experimental results, we could clarify the significant factors and the practical range of image quality of color e‐paper. For instance, both the reflectance of approximately 30% or higher, contrast ratio of approximately 8:1 or higher, and NTSC ratio of 20% or higher are the requirements for obtaining subjective evaluation score that is equivalent to that of newspapers, which are read very widely.
A longitudinal study of hearing and middle ear status in adolescents with cleft lip and palate
Authors: Flynn Traci , Lohmander Anette , Moller Claes , Magnusson Lennart 
Published: December 2012

Objectives/HypothesisTo study longitudinal prevalence of otitis media with effusion (OME) in children between 7 and 16 years of age by cleft group, and hearing sensitivity across time and across frequencies.Study DesignRetrospective and longitudinal.MethodsAll children with cleft palate born from 1991 to 1993 were included in the study (n = 58). Audiological and otological data were reviewed at 7, 10, 13, and 16 years of age. The group was divided by cleft type (24 unilateral cleft lip and palate, 23 cleft palate only, and 11 bilateral cleft lip and palate).ResultsThe prevalence of abnormal middle ear status decreased significantly with age. When comparing cleft types, the isolated cleft palate group presented with a significantly lower prevalence of abnormal middle ear status than the other groups at 7 and 16 years of age (21% as compared to 32% in the unilateral group and 38% in the bilateral group). The pure‐tone average improved with age, while the high‐frequency pure‐tone average did not. When cleft types were compared, the bilateral group demonstrated significantly poorer hearing in the high frequencies than the other groups.ConclusionChildren with cleft palate need regular audiological and otological follow‐up to ensure management is appropriate and timely. The increased hearing thresholds in the high frequencies may be due to the increased episodes of OME.Level of Evidence2B.
Consumer Participation: The Case of Home Meal Preparation
Authors: Olsen Svein Ottar , Mai Huynh Thi Xuan 
Published: December 2012

ABSTRACTConsumer participation (CP) has become an important topic in marketing literature with the emergence of service‐dominant logic (SD logic), where consumers are viewed as co‐creators or coproducers of value. However, most studies of CP have largely focused on its economic implications for the supplying firm and thus not much attention has been paid to the factors explaining this phenomenon. This study explains the CP process in the context of home meal preparation by proposing and testing a model of how convenience orientation and knowledge influence both a motivational (involvement) and a behavioral component (time use) of a CP process. The results show that high involvement is a main driver of CP behavior. Convenience‐oriented people are less involved and spend less time on CP activities. Knowledge is suggested to have a positive influence on involvement with CP, but it may not necessarily positively impact the time people use in CP because skills may bring about efficient performance.
The maternal‐to‐zygotic transition: An asynchronous split
Authors: Kong Betty Y. , Woodruff Teresa K. 
Published: December 2012

AbstractThe early cell cycles of preimplantation embryo development are unique in the scheme of mitotic cell proliferation as cell division is not coupled to cell growth, leading to a halving of blastomere volume with each cleavage event. Among the early mouse embryonic divisions, the fi rst two are particularly different, lasting almost twice as long as subsequent divisions. The third cell cycle is marked by the transition of a four‐cell embryo into an eight‐cell embryo, and represents the fi rst complete cell cycle occurring after activation of the zygotic genome. The G2/M phase of the third cell cycle is highly variable, lasting between 2–5 hours, and heterogeneity between blastomeres within the same embryo may occur as a part of normal development.The embryo in this image is actively undergoing cleavage from the four‐ to the eight‐cell stage, and blastomeres are captured in multiple phases of the cell cycle, as visualized by chromatin structure (DNA, blue) and microtubule staining (α‐tubulin, green). Two blastomeres sit in interphase with decondensed chromatin masses and a mesh‐like microtubule network, while the remaining blastomeres are actively undergoing mitosis. Of the latter, one is in metaphase, one in early anaphase, and the last in late anaphase. All together, the diversity in cell cycle stages reveals the inherit asynchrony existent within individual blastomeres of a cleavage stage embryo. Mol. Reprod. Dev. 80: 1–1, 2012. © 2012 Wiley Periodicals, Inc.
Production of PMMA Nanoparticles Loaded with Praziquantel Through “In Situ” Miniemulsion Polymerization
Authors: Fonseca Laís B. , Nele Márcio , Volpato Nádia Maria , Seiceira Rafael C. , Pinto José Carlos 
Published: December 2012

AbstractPZQ is the primary drug for treatment of schistosomiasis, but its efficiency is severely affected by its bitter taste. The main objective of this paper is the preparation of PMMA nanoparticles loaded with PZQ through in situ miniemulsion polymerizations and intended for oral formulations. Polymerizations are performed with an ultra turrax and a high‐pressure homogenizer. Obtained nanoparticles are analyzed by DSC, HPLC, DLS, GC, SEM, and PZQ dissolution profiles. Obtained results indicate the successful encapsulation of PZQ in all runs. Obtained data also show that the high‐pressure homogenizer leads to the best performance, allowing for preparation of stable latexes, with narrower particle size distributions and higher encapsulation efficiencies. magnified image
Effects of low energy e‐beam irradiation on cathodoluminescence from GaN
Authors: Suihkonen S. , Nykänen H. , Tanikawa T. , Yamaguchi M. , Honda Y. , Amano H. 
Published: December 2012

AbstractWe present cathodoluminescence (CL) studies on low energy e‐beam irradiated (LEEBI) metal‐organic vapor phase epitaxy (MOVPE) grown GaN films. High intensity LEEBI has been reported to reduce the band‐edge photoluminescence intensity of MOVPE grown GaN films. Here we observe similar reduction of band‐edge CL intensity with increasing LEEBI dose. The irradiation damage is found to be concentrated in the LEEBI energy dissipation depth by CL depth profiling. We have previously attributed the LEEBI induced reduction of band‐edge intensity to the activation of in‐grown Ga‐vacancies. Here we observe no increase in the relative intensity of defect related yellow or blue CL emission peaks in the LEEBI treated samples. This indicates that blue or yellow emission in undoped GaN is not related to in‐grown Ga‐vacancies.
Mother tongue as default language of instruction in lower primary science classes: Tension between policy prescription and practice in Nigeria
Authors: Okebukola Peter Akinsola , Owolabi Olatunde , Okebukola Foluso Olutoyin 
Published: December 2012

AbstractThe forecast for the first quarter of this century is that the issue of teaching science in the language to which the learner is most familiar will receive more attention in our quest to win more students for science. Over two‐thirds of countries in Africa, Asia, and Europe have developed policies on the use of the mother tongue for teaching science in the lower levels of their education system. In spite of this policy thrust, the educational system of many of these countries has not responded fully to the demands of such a policy. Because studies which mapped the dynamics of communication in science classrooms taught using the mother tongue are scant, we remain in the dark as to how best to structure such classrooms. The study was conducted in 12 primary schools and it involved 36 teachers in urban and rural locations of Lagos State, Nigeria. Quantitative and qualitative data were collected from primary science classrooms where the mother tongue is expected to be used as a medium of instruction. Mismatch between policy and practice was found especially in urban science classrooms. Among other things, it was found that on the average, science lessons delivered in primary 1 in rural settings, were found to be 93.6% in the mother tongue (L1). In primary 2 this fell to 91.1% and in primary 3–84.6%. In contrast, in the urban schools, mother tongue content was found to be 61.8% in primary 1, 49.2% in primary 2 and 26.6% in primary 3. The geo‐spatial communication between and among pupils in urban and rural science classes also showed interesting findings, that is, English served as a mediating language. The implications of the findings for future policy considerations and future research to inform policy are drawn. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 50:62–81, 2013
Preoperative Magnetic Resonance Angiography as a Predictive Test for Cerebral Ischemia During Carotid Endarterectomy
Authors: Shin Sung , Kwon Tae‐Won , Cho Yong‐Pil , Shin Ji Hoon , Yi Ann , Kim Hyangkyung , Kim Geun Eun 
Published: December 2012

AbstractBackgroundTo evaluate whether the preoperative magnetic resonance angiography (MRA) can predict the risk of cerebral ischemia associated with the carotid endarterectomy (CEA).MethodsBetween January 2004 and December 2010, 382 consecutive patients (mean age: 56.6 years; range: 45–78 years) were identified to have undergone preoperative MRA and the CEA under regional anesthesia. It was determined that the patient needs shunting during the CEA by intraoperative monitoring of patient’s neurology. All patients were divided into two subgroups: shunt group or no‐shunt group. Imaging findings on preoperative MRA were correlated to shunting using univariate and multivariate logistic regression analyses combined with patient’s demographic and clinical features to identify predictors of cerebral ischemia during the CEA.ResultsIn 37 of 382 CEA cases (9.7 %), shunting had been performed intraoperatively because the patient had a neurologic deficit. At multivariate analysis, preoperative MRA findings such as the absence of patent communicating arteries (odds ratio [OR], 5.56; 95 % confidence interval [CI], 3.05–9.69; p = 0.013) and the increase of intracranial arteries which were not patent in the contralateral hemisphere (OR, 4.277; 95 % CI, 2.575 to 7.104; p < 0.0001) were significantly associated with shunting.ConclusionsPreoperative MRA is valuable when predicting cerebral ischemia leading to an inevitable shunting during CEA. Therefore, if there are preoperative MRA findings such as multiple occlusive intracranial arteries in the contralateral hemisphere or the absence of patent communicating arteries, it is recommended that CEA be performed under general anesthesia with routine shunting to avoid a serious shunt‐related complication.
Lateral Incisional Hernia Repair by the Retromuscular Approach with Polyester Standard Mesh: Topographic Considerations and Long‐term Follow‐up of 61 Consecutive Patients
Authors: Veyrie Nicolas , Poghosyan Tigran , Corigliano Nicola , Canard Guillaume , Servajean Stephane , Bouillot Jean‐Luc 
Published: December 2012

AbstractBackgroundBecause of the lack of published data and the relative rarity of lateral incisional hernia (LIH), their repair remains a major challenge for surgeons. The aim of the present study was to evaluate the outcome of LIH treated by the retromuscular approach (RMA) with a polyester standard mesh.MethodsSixty‐one patients were treated between June 2000 and November 2007 in an academic tertiary referral center using one standardized surgical technique and one type of mesh. Lumbar incisional hernia was excluded. All data were prospectively culled. The early complications and recurrence rates were evaluated.ResultsThere were 14 (23 %) subcostal, 12 (19.6 %) flank, and 35 (57.4 %) iliac fossa LIH. The mean patient age was 57 years, and 60 % were male. The average width of the defect was 7.6 cm and the overall defect size averaged 56 cm². Seventeen patients (28 %) had had previous LIH repair. Ten patients had double hernia locations (midline and lateral) repaired simultaneously. The average operative time and hospital stay were 136 min and 7 days, respectively. The early complications rate was 18 %. Four patients required reoperation. There were no mesh infections. The median follow‐up was 47 months (range: 1–125 months). Recurrence was observed in three patients (4.9 %).ConclusionsLIH repair by RMA with a polyester heavyweight mesh proves to be a safe treatment with a moderate complication rate and a low infection rate, even in the treatment of large or multifocal parietal defects.
Information Literacy: 21st Century Library Research Methods for African Studies
Authors: Reboussin Daniel A. 
Published: December 2012

What is information literacy and why is it important for African studies?Today's information environment for African studies, as in other areas, is vastly different from what it was in the last century. The central problem for library researchers in African studies decades ago hinged on awareness of a relatively few specialist, published reference and other print bibliographic tools for discovering relevant materials (Frank-Wilson 2004: 106; see McIlwaine 2007a). Many more resources are available now from African and other sources, but they present a complex terrain to navigate for many reasons, both old and new (see Limb 2007). The field has become more interdisciplinary in terms of data sources and subject matter, making bibliographic searches in any single topical, geographical, or discipline-based source (or even in the most comprehensive index databases) less likely to fulfil all of one's scholarly needs. While scholarly sources of documentation are freely available online, these may be fragmentary, idiosyncratic or incomplete as citations are made available passively and without context through services such as Google Scholar.1Students may encounter library resources online without having developed the critical evaluation skills and contextual judgement that more experienced scholars may take for granted (Hargittaiet al. 2010), and which may be essential to employ during library research to identify and engage effectively with African scholarly perspectives.