bluuebunny/crossref_metadata_2025_split huggingface dataset:
DFT calculations of quadrupolar solid‐state NMR properties: Some examples in solid‐state inorganic chemistry
Authors: Cuny Jerome , Messaoudi Sabri , Alonzo Veronique , Furet Eric , Halet Jean‐François , Le Fur Eric , Ashbrook Sharon E. , Pickard Chris J. , Gautier Regis , Le Polles Laurent 
Published: June 2008

AbstractThis article presents results of first‐principles calculations of quadrupolar parameters measured by solid‐state nuclear magnetic measurement (NMR) spectroscopy. Different computational methods based on density functional theory were used to calculate the quadrupolar parameters. Through a series of illustrations from different areas of solid state inorganic chemistry, it is shown how quadrupolar solid‐state NMR properties can be tackled by a theoretical approach and can yield structural information. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
First‐principles lattice dynamics calculations of the phase boundary between β‐Si3N4 and γ‐Si3N4 at elevated temperatures and pressures
Authors: Togo Atsushi , Kroll Peter 
Published: June 2008

AbstractThe phase boundary between β‐Si3N4 and γ‐Si3N4 is investigated at high pressure and high temperature using first‐principles lattice dynamics calculations within the quasi‐harmonic approximation. We find a positive slope of the phase boundary, hence, at higher temperatures it requires higher pressures to synthesize the high‐pressure polymorph of silicon nitride. It turns out that the thermal expansion of the spinel‐type γ‐phase is larger than that of the phenacite‐type β‐phase. On the other side, pressure affects more the volume of β‐Si3N4 than of γ‐Si3N4, reflected in the higher bulk modulus of γ‐Si3N4 up to about 40 GPa. The origin of the different temperature behavior of these phases, consequently, is rooted in a larger volume dependence of the zero point energy in γ‐Si3N4 in comparison to β‐Si3N4. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
Adsorption of single Cu atoms at differently stabilized polar ZnO surfaces: An ab initio study
Authors: Hegemann Ilka , Schwaebe Andreas , Fink Karin 
Published: June 2008

AbstractIn this study, the adsorption of a single Cu atom on the polar ZnO(0001) and ZnO(000) surfaces was investigated by means of highly accurate wave function based ab initio methods. Different modifications of the polar surfaces were investigated: unstabilized surfaces, surfaces with hydrogen and OH overlayers, and defectious surfaces. Cu is strongly bound at the unstabilized surfaces by a charge transfer mechanism which induces a stabilization of the surface. At regular adsorption sites of stabilized surfaces the binding energies are much smaller. At oxygen defects, the Cu electron is transferred to the defect and a Cu+ ion sits on top of the defect. At the Zn terminated surface the Cu moves into the Zn defects. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
A new animal model for bone atrophic nonunion: Fixation by external fixator
Authors: Kaspar Katharina , Matziolis Georg , Strube Patrick , Sentürk Ufuk , Dormann Svenja , Bail Hermann J. , Duda Georg N. 
Published: June 2008

AbstractA new small animal model of bone atrophic nonunion was established for investigating the process of bone regeneration by performing cauterization of the periosteum, removal of the local bone marrow, and stabilization with external fixation. The model allows the creation of an atrophic nonunion without the need for a critical size defect. Furthermore, it provides reproducible, well‐defined mechanical conditions and minimized physical interference of the implant with the biological processes in the healing zone. Eighty adult Sprague‐Dawley rats received an osteotomy of the left femur, stabilized with an external fixator. In half of the animals, the periosteum proximal and distal to the osteotomy was destroyed by cauterization and the adjacent bone marrow was removed (nonunion group). At 2 and 8 weeks after surgery, radiological, biomechanical, histological, and histomorphometrical analyses showed a typical physiological healing in the control group, while the nonunion group was characterized by resorption of the bone ends with some callus formation distant to the osteotomy. At both time points, the callus was composed of significantly less bone and significantly more connective tissue (p < 0.001). In addition, the torsional strength of the osteotomized femur was significantly less in the nonunion group than in the control group, which was comparable to that of the intact femur (p < 0.001). In conclusion, the present model allows the induction of an atrophic nonunion without the need of a critical size defect. It is reproducible, provides standardized biomechanical conditions, and allows minimized interaction of the implant with the healing zone. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Climate variability during the Last Glacial Maximum in eastern Australia: evidence of two stadials?
Authors: Petherick Lynda , McGowan Hamish , Moss Patrick 
Published: June 2008

AbstractA high‐resolution, multiproxy record encompassing the last glacial–interglacial transition is presented for Native Companion Lagoon, a coastal site in subtropical eastern Australia. Rates of aeolian sedimentation in the lake were established by trace element analyses of lacustrine sediments and used as a proxy for aridity. In conjunction with sediment moisture content, charcoal and pollen these provide a multi‐decadal record of palaeoenvironmental variability for the period 33–18 k cal. yr BP. Results indicate that the Last Glacial Maximum in eastern Australia spanned almost 10 k cal. yr, and was characterised by two distinct cold dry events at approximately 30.8 k cal. yr BP and 21.7 k cal. yr BP. Provenance of selected sediment samples by trace element geochemical fingerprinting shows that continental sourced aeolian sediments originated primarily from South Australia during these cold events and from sites in central Australia during the intervening time. Used in combination with a pollen record, the provenance of long‐travelled dust to mainland sites shows that the two cold events were characterised by frequent meridional dry southwesterly winds rather than zonal westerly airflow as previously believed. The intervening period was cool and humid, which we infer as being associated with more frequent southeasterly winds of maritime origin. These results lend support to previous research that indicates the Southern Hemisphere experienced a period of widespread climatic amelioration at the height of the last glacial known as the Antarctic Isotopic Maximum. Copyright © 2008 John Wiley & Sons, Ltd.
Nanostructures and nanostructured substrates for surface—enhanced Raman scattering (SERS)
Authors: Brown Richard J. C. , Milton Martin J. T. 
Published: June 2008

AbstractWe review the performance of various nanoscaled structures needed to support the propagation of the surface plasmons responsible for surface‐enhanced Raman scattering (SERS), and assess the potential for the optimisation of the compromise between enhancement and reproducibility that they provide, and hence their utility for relevant applications. We divide these nanostructures into those comprising structured arrays of discrete nanoparticles in two or three dimensions, and those comprising structured or regularly patterned surfaces in two or three dimensions. The most promising in terms of this compromise are those that involve the tethering of functionalised metal nanoparticles to surfaces. They are not only reproducible, but the functionalisation provides a measure of selectivity to relevant target analytes that the majority of SERS applications require. Copyright © 2008 John Wiley & Sons, Ltd.
Randomized clinical trial to assess the efficacy of ulinastatin for postoperative pancreatitis following pancreaticoduodenectomy
Authors: Uemura Kenichiro , Murakami Yoshiaki , Hayashidani Yasuo , Sudo Takeshi , Hashimoto Yasushi , Ohge Hiroki , Sueda Taijiro 
Published: June 2008

AbstractBackground and ObjectivesUlinastatin, an intrinsic trypsin inhibitor, has proved to be effective for the prevention of acute pancreatitis after endoscopic retrograde cholangiopancreatography. The aim of this study was to assess the efficacy of ulinastatin for postoperative pancreatitis following pancreaticoduodenectomy in a randomized clinical trial.MethodsPatients undergoing pancreaticoduodenectomy were randomized to receive perioperative ulinastatin or placebo. Levels of serum amylase, drain amylase, and urine trypsinogen‐2 were measured.ResultsA total of 42 patients were enrolled (20 in the ulinastatin group, 20 in the placebo group, 2 excluded). Two patients in the ulinastatin group and nine patients in the placebo group developed hyperamylasemia (P = 0.013) No patient in the ulinastatin group and five patients in the placebo group developed pancreatitis (P = 0.016). One patient in the ulinastatin group and two patients in the placebo group developed grade A pancreatic fistula (P = 0.548). Serum amylase levels at 4 hr and postoperative days 1, 2, and 3, and drain amylase levels on days 2 and 3 were significantly lower in the ulinastatin group than in the placebo group.ConclusionsProphylactic administration of ulinastatin reduced the levels of serum and drain amylase and the incidence of postoperative pancreatitis following pancreaticoduodenectomy. J. Surg. Oncol. 2008;98:309–313. © 2008 Wiley‐Liss, Inc.
Simultaneous determination of macrolides, sulfonamides, and other pharmaceuticals in water samples by solid‐phase extraction and LC‐(ESI) MS
Authors: Pedrouzo Marta , Borrull Francesc , Marcé Rosa Maria , Pocurull Eva 
Published: June 2008

AbstractThis paper describes a method for determining 11 pharmaceuticals in various water sources by SPE followed by LC‐(ESI) MS. SPE was carried out with OasisTM HLB and the recoveries were 33–67% for 250 and 100 mL sewage water, 55–77% for 500 mL river water and 72–98% for 1 L tap water, with the exception of sulfamethoxazole and omeprazole which showed lower recoveries in all kinds of sample. The LODs in river water were of 5 ng/L for sulfadiazine, trimethoprim, sulfamethazine, sulfamethoxazole, and ranitidine and 10 ng/L for the other compounds. The highest concentrations found in river waters were for sulfamethoxazole (50 ng/L). In influent sewage waters, ranitidine was the most commonly detected compound with a maximum value of 0.24 μg/L.
Determination of tricyclic antidepressants in human plasma using pipette tip solid‐phase extraction and gas chromatography–mass spectrometry
Authors: Lee Xiao‐Pen , Hasegawa Chika , Kumazawa Takeshi , Shinmen Natsuko , Shoji Yukiko , Seno Hiroshi , Sato Keizo 
Published: June 2008

AbstractA method for the simultaneous extraction of four tricyclic antidepressants from human plasma samples using pipette tip SPE with MonoTip C18tips is presented. Human plasma (0.1 mL) containing four tricyclic antidepressants (amitriptyline, amoxapine, imipramine, and trimipramine) and an internal standard (IS), protriptyline, was mixed with 0.4 mL of distilled water and 100 μL 1 M NaOH solution. After centrifugation of the mixture, the supernatant was extracted to the C18phase of the tip by 20 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained in the tip were eluted with methanol by five repeated aspirating/dispensing cycles. Without evaporation and reconstitution, the eluate was directly injected into a gas chromatograph injector and detected by a mass spectrometer with SIM in the positive‐ion electron impact mode. Recovery of the four antidepressants and IS spiked into human plasma was 80.2–92.1%. The regression equations for the four antidepressants showed excellent linearity in the range of 0.2–40 ng/0.1 mL. LODs and LOQs for the four drugs were 0.05–0.2 ng/0.1 mL and 0.2–0.5 ng/0.1 mL, respectively. Intra‐ and interday CVs for the four drugs in plasma were no greater than 9.5%.
Preparative isolation of guaipyridine sesquiterpene alkaloid from Artemisia rupestris L. flowers using high‐speed counter‐current chromatography
Authors: Su Zhen , Wu Hankui , Yang Yi , Aisa Haji Akber , Slukhan Usmanova , Aripova Salimakhon 
Published: June 2008

AbstractAlthough the medicinal plant Artemisia rupestris L. has been widely researched for several decades, its alkaloids have never been isolated before. To our surprise, the alkaloids in the plant were not detected in the stems but detected in the flowers. Herein, a novel and strange guaipyridine sesquiterpene alkaloid with a carboxyl group named rupestine was purified successfully from the total alkaloids extracted from the flowers by high‐speed counter‐current chromatography (HSCCC). The two‐phase solvent system used was composed of ethyl acetate‐methanol‐water (8:1:7, v/v/v). Fifty six milligrams of rupestine was obtained at over 97% purity and 95% recovery from 200 mg of the total alkaloids in one‐step separation. Its structure was elucidated by spectroscopic methods including high resolution ESI‐MS, 1H NMR, 13C NMR, Heteronuclear Multiple Bond Correlation (HMBC), Heteronuclear Single Quantum Coherence (HSQC), and Nuclear Overhauser Enhancement Spectroscopy (NOESY).
Sample preparation for the determination of steroids (corticoids and anabolics) in feed using LC
Authors: Muñiz‐Valencia Roberto , Ceballos‐Magaña Silvia G. , Gonzalo‐Lumbreras Raquel , Santos‐Montes Ana , Izquierdo‐Hornillos Roberto C. 
Published: June 2008

AbstractAn improved sample preparation procedure for the determination of 17 steroids (corticoids (CC) and androgenic anabolic steroids (AAS)), used potentially as growth promoters, in feed samples has been developed. This procedure is based on two reported LC‐UV methods. The improved procedure includes a leaching process using ACN, saponification, and SPE using polymeric cartridges. The proposed method was validated according to the EU criteria established for quantitative screening methods in PFS. The extraction efficiencies, decision limits (CCα) and detection capabilities (CCβ), for these compounds were in the ranges of 82–100%, 19–40, and 24–53 μg/kg, respectively. The repeatability and the within‐laboratory reproducibility at 1.0, 1.5, and 2.0 CCβ levels were smaller than 10%. Accuracy was in the 97–101% range. The robustness was evaluated using the Youden robustness test. This method was applied to the analysis of steroids in different kinds of FS with satisfactory results.
Kinetics of elimination reactions of 1,2‐diphenyl ethyl substrates in acetonitrile: A mechanistic change in the presence of a strong base
Authors: Kumar D. Santhosh , Balachandran S. 
Published: June 2008

AbstractKinetics of elimination of methanesulfonic acid from 1,2‐diphenylethylmethane sulfonate and its 1‐p‐methylphenyl‐ and 1‐p‐chlorophenyl‐substituted derivatives is studied. The results show that the elimination reaction is unimolecular (E1) as reported in the case of 1‐chloro‐1‐(4‐methoxyphenyl)‐2‐phenylethane. The rate of the elimination reaction in the presence of added weak base pyridine is independent of the concentration of the base, but in the presence of a strong base piperidine the rate shows a linear upward drift and this is due to the appearance of a bimolecular component along with the unimolecular pathway. The shift from the unimolecular to bimolecular process takes place independently of the nature of the leaving group and the parasubstituent in the 1,2‐diphenylethyl substrate. © 2008 Wiley Periodicals, Inc. 40: 481–487, 2008
Studies on kinetics and mechanism of oxidation of D‐sorbitol and D‐mannitol by cerium(IV) in aqueous micellar sulfuric acid media
Authors: Das Asim K. , Islam Monirul , Bayen Ruhidas 
Published: June 2008

AbstractThe kinetics and mechanism of cerium(IV) oxidation of hexitols, i.e. D‐sorbitol and D‐mannitol, in aqueous sulfuric acid media have been studied in the presence and absence of surfactants. Under the kinetic conditions, [S]T ≫ [Ce(IV)]T, where [S]T is the total substrate (D‐sorbitol or D‐mannitol) concentration, the overall process shows a first‐order dependence on [Ce(IV)]T and [S]T. The process is acid catalyzed and inhibited by [HSO]. From the [HSO] dependence, it has been noted that the both Ce(SO4)2+ and Ce(SO4)2 have been found kinetically active. The different rate constants in the presence and absence of surfactants have been estimated with the activation parameters. N‐cetylpyridinium chloride has been found to retard the oxidation process of hexitols, whereas sodium dodecyl sulfate has been found to accelerate the rate process. All these findings including the micellar effects have been interpreted in terms of the proposed reaction mechanism and partitioning behavior of the kinetically active different species of Ce(IV) between the aqueous and pseudomicellar phase. © 2008 Wiley Periodicals, Inc. 40: 445–453, 2008
Adding insult to injury: opportunistic treponemal disease in a scalping survivor
Authors: Smith M. O. 
Published: June 2008

AbstractAlthough the taking of scalps is arguably a perimortem trophy‐taking behaviour, cases of scalping survival are occasionally reported in the historical documents of the American Colonial Period and the 19th century westward expansion. Survival cases are also detected in pre‐Columbian bioarchaeological contexts. Although scalp avulsion injuries can heal without complication, often the process is compromised by secondary osteomyelitis, usually attributable to environmentally ever‐present Staphylococcal or Streptococcal bacteria. A scalping survivor case from the late prehistoric (AD 1200–1600) Hampton site (40RH41) of East Tennessee unusually displays infectious sequelae in the area denuded by scalp avulsion which are pathognomonic for treponemal disease (caries sicca, stellate scarring). This infection is probably a reflection of the easy opportunity afforded by the large size of the wound bed, poor post‐trauma hygiene, and direct inoculation of the diploë by a ubiquitous Treponema. Copyright © 2008 John Wiley & Sons, Ltd.
Amelogenesis imperfecta in an early 20th century population from central Portugal
Authors: Wasterlain S. N. , Dias G. J. 
Published: June 2008

AbstractThis paper details the differential diagnosis of an unusual tooth morphology observed in two adult males from the identified osteological collections held at the Museum of Anthropology of the University of Coimbra, Portugal. The differential diagnosis is based on the morphological and radiographic analysis of the teeth of these individuals, and gives rise to several possible pathological conditions, namely: regurgitation erosion, mottled enamel due to fluorosis, dentinogenesis imperfecta, amelogenesis imperfecta, and osteogenesis imperfecta. Of these, amelogenesis imperfecta remains the most probable cause for one individual, and although dentinogenesis imperfecta was considered for the other based on the morphological features, the final diagnosis was changed to the former based on accurate radiological evidence. Since there are only a few reported cases of these conditions in the osteoarchaeological literature, we find it to be interesting and important to report these two cases. The scarcity of reports in the palaeopathological literature, compared with the prevalence of these tooth structure anomalies in living populations, lead us to consider amelogenesis imperfecta and dentinogenesis imperfecta to be probably misdiagnosed, and hence under‐reported. Copyright © 2008 John Wiley & Sons, Ltd.
Epiphyseal fusion in brown bears: a population study of grizzlies (Ursus arctos horribilis) from Montana and Wyoming
Authors: Weinstock J. 
Published: June 2008

AbstractThis contribution presents results of a study of the timing of appendicular epiphyseal fusion in brown bears (Ursus arctos) based on the visual examination of 86 modern skeletons of grizzlies (U. a. horribilis) of known age and sex from the greater Yellowstone area, in the States of Wyoming and Montana (US). The timing of fusion in brown bears was compared with the (scant) information available for the black bear (Ursus americanus); both similarities and differences were found. It is still inconclusive whether the discrepancies stem from the methods of study (visual examination vs. X‐rays) or whether they reflect real difference in fusion ages. It is suggested that data derived from U. arctos can be used profitably to investigate mortality patterns of extinct bears such as the cave bear Ursus spelaeus. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of nano ZnO on strength and stability of unsaturated polyester composites
Authors: Peng Guirong , Li Qingshan , Yang Yanling , Wang Haifeng , Li Wei 
Published: June 2008

AbstractZnO–glass fiber–unsaturated polyester composites have been prepared. On exposure to the metal halide lamp, their resistance to ultraviolet (UV) degradation is evaluated. Experimental results show that ZnO can reduce the UV degradation of the unsaturated polyester matrix. ZnO can significantly retard the UV degradation process of the matrix resin, and can also increase the impact strength of the composites under the experimental conditions. Differential scanning calorimetry (DSC) analyses also indicate that the addition of ZnO to unsaturated polyester may retard the crosslink process and catalyze the decomposition of the resin. However, after more than 40 hr of UV irradiation, it was crosslinked. SEM fracture morphology shows that nano ZnO could hinder crack growth and induce more cracks, and when the content of ZnO reaches 6 wt%, the impact fracture mechanism changes abruptly and plastic deformation appears, which indicates that 6 wt% for ZnO in unsaturated polyester could be considered as the critical content. Around the critical content, the particles are near enough to interact with each other and this results in the change of fracture mechanism. The results also indicate that the proper content of ZnO added into an unsaturated polyester could prolong the durability and lessen the reject rate of transparent glass fiber–polyester composites. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of polymer chain length on the solubility of polystyrene grafted single‐walled carbon nanotubes in tetrahydrofuran
Authors: Homenick Christa M , Sivasubramaniam Umakanthan , Adronov Alex 
Published: June 2008

AbstractBACKGROUND: While carbon nanotubes are highly interesting materials for a variety of applications, their inherent insolubility limits widespread applications and solution‐phase processing. It is known that chemical functionalization can overcome this insolubility problem, and covalent grafting of polymers to the nanotube surface has been shown to be effective. In this study, the effect of polymer molecular weight on the solubility of polymer–nanotube conjugates was investigated.RESULTS: A series of nitroxide‐capped polystyrene polymers ranging in molecular weight from 2900 to 105 000 g mol−1 were grafted to single‐walled carbon nanotubes (SWNTs). The resulting polystyrene–SWNT conjugates exhibited different degrees of solubility in tetrahydrofuran. Subsequent thermogravimetric and UV‐visible spectroscopy analyses indicated that carbon nanotube solubility reached a maximum when a polymer sample with a weight‐average molecular weight of 10 000 g mol−1 was used. Higher and lower molecular weights resulted in reduced solubilities.CONCLUSION: Polymer chains of intermediate length maximize SWNT solubility, while lengths that are too low or too high seem to diminish the ability of the polymer–SWNT conjugates to remain in solution. Copyright © 2008 Society of Chemical Industry