bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple reflection and transmission phases in complex layered media using a multistage fast marching method
Authors: Rawlinson N. , Sambridge M. 
Published: September 2004

Traditional grid‐based eikonal schemes for computing traveltimes are usually confined to obtaining first arrivals only. However, later arrivals can be numerous and of greater amplitude, making them a potentially valuable resource for practical applications such as seismic imaging. The aim of this paper is to introduce a grid‐based method for tracking multivalued wavefronts composed of any number of reflection and refraction branches in layered media. A finite‐difference eikonal solver known as the fast marching method (FMM) is used to propagate wavefronts from one interface to the next. By treating each layer that the wavefront enters as a separate computational domain, one obtains a refracted branch by reinitializing FMM in the adjacent layer and a reflected branch by reinitializing FMM in the incident layer.To improve accuracy, a local grid refinement scheme is used in the vicinity of the source where wavefront curvature is high. Several examples are presented which demonstrate the viability of the new method in highly complex layered media. Even in the presence of velocity variations as large as 8:1 and interfaces of high curvature, wavefronts composed of many reflection and transmission events are tracked rapidly and accurately. This is because the scheme retains the two desirable properties of a single‐stage FMM: computational speed and stability. Local grid refinement about the source also can increase accuracy by an order of magnitude with little increase in computational cost.
A Naphthalimide Fluorescent Sensor for Zn2+ Based on Photo-induced Electron Transfer
Authors: Fan Jiangli , Wu Yunkou , Peng Xiaojun 
Published: September 2004

Abstract
A new Zn2+ fluorescent sensor NIDPA (1) which takes 1,8-naphthalimide as a reporting group and di-2-picolylamine (DPA) as a recognizing group has been synthesized via simple steps. Based on photo-induced electron transfer (PET) mechanism, NIDPA has a nearly 5-fold fluorescent enhancement under simulated physiological conditions corresponding to the binding of Zn2+. Apparent dissociation constant for Zn2+ (Kd) is in the sub-nM range, and Ca2+, Mg2+, Fe3+, Ni2+, and Cr3+ have little influence on fluorescence enhancement.
Tápanyagellátás hatása a sárgarépára (Daucus carota L.) karbonátos csernozjom talajon
Authors: Kádár Imre 
Published: September 2004

Karbonátos csernozjom vályogtalajon egy mutrágyázási tartamkísérlet 21. évében vizsgáltuk az eltéro NPK-ellátottsági szintek és kombinációik hatását a Vörös óriás fajtájú sárgarépa (Daucus carota L.) fejlodésére, gyomosodására, termésére, lombjának és gyökerének ásványi összetételére. A termohely talaja a szántott rétegben mintegy 3% humuszt, 5% CaCO3-ot és 20% agyagot tartalmazott; N, K, Mg, Mn, Cu elemekkel közepesen, P és Zn elemekkel gyengén ellátottnak minosült. A kísérlet 4N×4P×4K = 64 kezelést és 2 ismétlést foglalt magában, összesen 128 parcellával. A mutrágyázás pétisó, szuperfoszfát és kálisó formájában történt. Az 5,5 hó tenyészido alatt 205 mm csapadék hullott mindössze. Fobb eredmények: - Május elején a sárgarépa csupán 3% borítottságot jelzett, vontatottan kelt, míg a gyomborítás (Amaranthus blitoides) 2%-ról 50-60%-ra ugrott az együttes PK-túlsúly nyomán. - A maximális 26-28 t/ha gyökérterméseket a nitrogénnel és foszforral 21 éve nem trágyázott kezelések adták, ahol 80-100 mg/kg ammónium-laktát- (AL-) oldható P2O5-, ill. 200-300 mg/kg AL-K2O-tartalom volt a szántott rétegben. 200 mg/kg AL-P2O5-tartalom felett a termés drasztikusan csökkent, ill. az extrém PK-túltrágyázás nyomán a növény gyakorlatilag kipusztult és a talaj elgyomosodott. - A növény tápláltsági állapota a gyökérképzodés kezdetén vett lomb analízisével jól nyomon követheto, az irodalomban közölt optimum koncentrációk iránymutatóak. Eredményeink szerint ideális a 2-3% N, 0,3-0,4% P, 3-4% K, 1-3 mg/g NO3-N, valamint az 5-10 N/P, 0,5-1,0 N/K, 8-13 K/P és a 80-150 P/Zn aránya a légszáraz lombban. - A N-trágyázás növelte a növényi szervek N-, NO3-N-, Mn-, ill. mérsékelte a S-, Ba- és Mo-készletét. A P-kínálattal emelkedett a P-, Sr-, Mo- és Cd-, ill. csökkent a Zn-, Cu-, Fe- és Al-koncentráció. A K-kínálattal nott a K, valamint igazolhatóan süllyedt az egyéb vizsgált elemek (N, Ca, Mg, Na, Sr, B, Ni, Cr és Cd) mennyisége a lombban és a gyökérben. - A betakarításkori 8 t/ha lomb + 24 t/ha gyökér, azaz 32 t/ha friss terméssel a sárgarépa 113 kg K, 90 kg N, 89 kg Ca, 21 kg Na, 18 kg Mg, 15 kg P, 12 kg S, 2-3 kg Fe és Al, 411 g Mn, 272 g Sr, 160 g Ba, 129 g B, 111 g Zn, 40 g Cu, 8 g Ni, 5 g Cr, 3 g Pb, 1-2 g Co és 0,5 g Cd elemet akkumulált. - A hazai szaktanácsadásban ajánlott 40-15-50-16-16 = N-P2O5-K2O-CaO-MgO fajlagos mutatók, azaz 10 t friss gyökér + a hozzá tartozó lomb elemtartalmának irányszámai, összességükben megerosítést nyertek kísérletünkben. Kivételt a kísérletben mért extrém fajlagos CaO érték jelenthet, mely a meszes termohelyre és az aszályos évjáratra vezetheto vissza.
Thioxoethenylidene C2S: A Matrix‐Spectroscopic Study
Authors: Maier Günther , Reisenauer Hans Peter , Ruppel Raimund 
Published: September 2004

AbstractThioxoethenylidene C2S (5), known for its high abundance in interstellar space, has been generated by irradiation of C3S2 (4) and C3OS (6) in an argon matrix at 10 K. Its structural elucidation is based on comparison of the experimental and calculated IR and UV spectra. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Some Reactions of Magnesium Arylporphyrazines: Evidence of Dehydroporphyrazine Formation
Authors: Vagin Sergej , Hanack Michael , Kammerer Bernd , Frickenschmidt Antje 
Published: September 2004

AbstractThe reactivity of the 2,3‐dibromobenzo‐annulated 2,3,7,8,12,13‐hexakis(m‐trifluoromethylphenyl)porphyrazine magnesium complex 1 towards butyllithium and tert‐butylmagnesium chloride in the presence of metallic magnesium was studied. It was found that n‐butyllithium reacts mainly with the porphyrazine macrocycle to give tetraazachlorins and other reduction products, similarly to porphyrins. On treatment of 1 with tBuMgCl and Mg, dehydroporphyrazine 4 (arynoporphyrazine) was generated and trapped with furan, confirming the possibility of the formation of a dehydrophthalocyanine. The structures of the products were verified by UV/Vis and NMR spectroscopy, and also mass spectrometry (MALDI‐TOF). Utilization of the tetrapyrrolic macrocycle 1 for this type of reaction may become a new synthetic strategy for unsymmetrical peripheral derivatization of phthalocyanines and related compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of two Conformationally Restricted Piperazine Scaffolds for Combinatorial Chemistry
Authors: Opatz Till 
Published: September 2004

AbstractPiperazines are widely used as central elements in the construction of bioactive molecules. Herein, the short synthesis of two chiral 2,6‐bridged piperazines possessing orthogonally stable protecting groups from readily available starting materials is described. It is suggested that these molecules may be used as conformationally restricted scaffolds for the combinatorial synthesis of drug‐like compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Brominated 4‐(Trifluoromethyl)pyrimidines: A Convenient Access to Versatile Intermediates
Authors: Ondi Levente , Lefebvre Olivier , Schlosser Manfred 
Published: September 2004

AbstractAn expedient route to all three monobrominated and all three dibrominated isomers of 4‐(trifluoromethyl)pyrimidine, and to several other halogenated pyrimidines, is described. Key steps are the electrophilic introduction of the halogen in the 5‐position of 2‐ or 4‐pyrimidinones, the bromodeoxygenation of pyrimidinones or thiopyrimidinones using phosphorus tribromide, and the partial debromination of dibromo‐4‐(trifluoromethyl)pyrimidines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Arthrobacter sp. JS443‐Based Whole Cell Amperometric Biosensor for p‐Nitrophenol
Authors: Lei Yu , Mulchandani Priti , Chen Wilfred , Wang Joseph , Mulchandani Ashok 
Published: September 2004

AbstractAn amperometric microbial biosensor for highly sensitive and selective determination of p‐nitrophenol (PNP) is reported. The biosensor consisted of PNP‐degrader Arthrobacter sp. JS443 immobilized by entrapment in Nafion polymer deposited on the top of the carbon paste electrode transducer. The biosensor was based on the measurement of the oxidation current of the intermediates 4‐nitrocatechol and 1,2,4‐benzenetriol formed by the highly selective oxidation of PNP by Arthrobacter sp. The sensor signal and response time were optimized with applied potential of +0.4 V (vs. Ag/AgCl reference electrode) and 0.03 mg of cells and operating in pH 7.5, 50 mM citrate‐phosphate buffer at room temperature. When operated at optimized conditions, the Arthrobacter sp.‐based biosensor measured as low as 5 nM (0.7 ppb) of PNP. The biosensor demonstrated excellent selectivity with no interference from phenolic compounds such as 2‐nitrophenol, phenol and 3‐chlorophenol but was interfered by 3‐nitrophenol and 3‐methyl‐4‐nitrophenol. It had good precision and intra‐ and inter‐day reproducibility, accuracy and was stable up to 3 days when stored in buffer at 4 °C. When applied for measurement in water from Lake Elsinore, CA, the results obtained were in excellent agreement with the amounts determined spectrophotometrically.
Frequent p16INK4a promoter hypermethylation in human papillomavirus‐infected female lung cancer in Taiwan
Authors: Wu Ming‐Fang , Cheng Ya‐Wen , Lai Ji‐Ching , Hsu Min‐Chih , Chen Jung‐Ta , Liu Wen‐Shan , Chiou Ming‐Chih , Chen Chih‐Yi , Lee Huei 
Published: September 2004

AbstractInactivation of p16INK4a gene through promoter hypermethylation has been frequently observed in non small cell lung cancer; however, various studies have shown a controversial correlation between p16INK4a hypermethylation and cigarette smoking. Our recent report showed that human papillomarvirus (HPV) 16/18 infections were associated with the development of nonsmoking female lung cancer in Taiwan and we further speculated that HPV infection may be linked with p16INK4a hypermethylation. To verify the influence of environmental exposure, including cigarette smoking, environmental carcinogen exposure and HPV infections on p16INK4a hypermethylation, tumors from 162 lung patients, including 67 smoking males, 41 nonsmoking males and 58 nonsmoking females, were subjected to p16INK4a hypermethylation analysis by methylation‐specific PCR. As the results showed, p16INK4a hypermethylation was detected in 40 (59.7%) of 67 smoking male, 15 (36.6%) of 41 nonsmoking male and 35 (60.3%) of 58 nonsmoking female lung tumors. This result seemed to reveal that gender and cigarette smoking both possess an equal influence on p16INK4a hypermethylation. This result also led to a speculation that HPV infection may promote p16INK4a hypermethylation in nonsmoking female lung cancer patients. From our data, p16INK4a hypermethylation frequency in nonsmoking female lung tumors with HPV infection was as high as 70% (30 of 43) compared to those without HPV infection (33%; 5 of 15). In fact, the correlation between HPV infection and p16INK4a hypermethylation was only observed in nonsmoking female lung tumors (p = 0.017), but not in smoking male or nonsmoking male lung tumors. Moreover, the reverse correlation between p16INK4a immunostaining and p16INK4a promoter hypermethylation was also only observed in nonsmoking female lung tumors. These results strongly suggested that the involvement of HPV infection in lung tumorigenesis of nonsmoking female cancer patients in Taiwan may be mediated at least in part through the increase of hypermethylation to cause p16INK4a inactivation.
Prospective study of risk factors for esophageal and gastric cancers in the Linxian general population trial cohort in China
Authors: Tran Gina D. , Sun Xiu‐Di , Abnet Christian C. , Fan Jin‐Hu , Dawsey Sanford M. , Dong Zhi‐Wei , Mark Steven D. , Qiao You‐Lin , Taylor Philip R. 
Published: September 2004

AbstractEsophageal cancer incidence and mortality rates in Linxian, China are among the highest in the world. We examined risk factors for esophageal squamous cell carcinoma (ESCC), gastric cardia cancer (GCC), and gastric noncardia cancer (GNCC) in a population‐based, prospective study of 29,584 adults who participated in the Linxian General Population Trial. All study participants completed a baseline questionnaire that included questions on demographic characteristics, personal and family history of disease, and lifestyle factors. After 15 years of follow‐up, a total of 3,410 incident upper gastrointestinal cancers were identified, including 1,958 ESCC, 1,089 GCC and 363 GNCC. Cox proportional hazard models were used to estimate risks. Increased age and a positive family history of esophageal cancer (including ESCC or GCC) were significantly associated with risk at all 3 cancer sites. Additional risk factors for ESCC included being born in Linxian, increased height, cigarette smoking and pipe smoking; for GCC, male gender, consumption of moldy breads and pipe smoking; and for GNCC, male gender and cigarette smoking. Protective factors for ESCC included formal education, water piped into the home, increased consumption of meat, eggs and fresh fruits and increased BMI; for GCC, formal education, water piped into the home, increased consumption of eggs and fresh fruits and alcohol consumption; and for GNCC, increased weight and BMI. General socioeconomic status (SES) is a common denominator in many of these factors and improving SES is a promising approach for reducing the tremendous burden of upper gastrointestinal cancers in Linxian.
Tensile properties and biological response of poly(L‐lactic acid) felt graft: An experimental trial for rotator‐cuff reconstruction
Authors: Aoki Mitsuhiro , Miyamoto Shigenori , Okamura Kenji , Yamashita Toshihiko , Ikada Yoshito , Matsuda Shojiro 
Published: September 2004

AbstractPoly(L‐lactic acid) felt (PLLA felt) was prepared for reconstruction of the rotator cuff in animal models. Small changes were found in the tensile strength of both the cultured PLLA felt and the PLLA felt implanted on the paravertebral muscle of rabbits up to 16 postoperative weeks. The stiffness of the felt implanted on the muscle from 6 to 16 weeks showed a statistically significant increase. When the infraspinatus tendons of beagle dog were reconstructed with the PLLA felt, the ultimate strength of PLLA felt increased threefold, and the stiffness increased fivefold by 16 postoperative weeks compared to that of the initial PLLA felt. They were statistically significant (p < 0.01). All the implanted specimens ruptured at the junction between the bone and the PLLA felt. Histological examination demonstrated infiltration of fibrous tissue into the interstices of the PLLA felt fibers. Connection between the infraspinatus tendon and the PLLA felt was tight with the formed scar tissue, but the connective tissue between the bone and PLLA felt fibers was sparse even at 16 and 32 postoperative weeks. A few deteriorated PLLA felt fibers were observed at 32 postoperative weeks. It was concluded that the degradation rate of PLLA felt was low and the tensile recovery of the PLLA felt graft in beagle dogs was excellent. Thus, PLLA felt might be a useful bioabsorbable material for rotator‐cuff reconstruction. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 252–259, 2004
Exudation of organic anions by roots of cabbage, carrot, and potato as influenced by environmental factors and plant age
Authors: Dechassa Nigussie , Schenk Manfred K. 
Published: September 2004

AbstractA previous study demonstrated that cabbage was P efficient compared to carrot and potato. However, calculating plant P uptake by a mechanistic simulation model based on P transport by diffusion and mass flow, P uptake of roots according to the Michaelis‐Menten kinetics, and morphological root characteristics including root hairs, revealed that these parameters could explain only 2/5 of the total P uptake of cabbage, but 4/5 of that of carrot and potato (Dechassa et al., 2003). Therefore, it was hypothesized that a higher root exudation of organic anions may enhance P mobilization and hence P uptake of cabbage. The objective of this research was to determine root exudation of organic anions by the three species, and to investigate the influence of plant age and dark/light period on organic‐anion exudation by cabbage. Experiments were conducted in a growth chamber in nutrient solution with or without P. Organic anions were determined in root exudates and in root tissue. With cabbage and potato, P deficiency induced exudation of citrate and succinate, respectively. Citrate‐exudation rate of P‐deficient cabbage plants was correlated with accumulation of citrate in root tissue. In contrast, high succinate‐exudation rates in potato were not correlated with an increased concentration in root tissue. For carrot, no change was observed in the exudation of any of the organic anions in response to P deficiency. The results also showed that succinate‐ and citrate‐exudation rates of cabbage roots increased with increased plant age. There was also a significant increase in exudation rates of organic anions of cabbage roots during the light period of the day. It was concluded that cabbage had the ability to exude large amounts of citrate in response to P deficiency by which it can additionally enhance its P‐uptake efficiency, whereas carrot and potato showed little evidence of possessing such a mechanism.
Microbial biomass and activity in composts of different composition and age
Authors: Gattinger Andreas , Bausenwein Ursula , Bruns Christian 
Published: September 2004

AbstractThe aim of this study was to perform a comparison of microbial activity and biomass in biowaste (BWC), yard waste (YWC), and cattle‐manure composts (CMC) of different age. Two different methods for either biomass (microbial C following fumigation‐extraction and microbial lipid phosphate) or activity measurements (CO2‐production rate and fluorescein diacetate hydrolysis) provided comparable information, as judged from their strong correlation. Microbial biomass and activity declined with time in all composts. Microbial biomass C was strongly correlated with microbial activity but was even stronger correlated with pH. CMC proved to be very distinct from the two other compost types by having the highest biomass and the lowest specific activity (i.e., activity per unit biomass). The microbiological properties analyzed allow us to discriminate among different compost types, helping to assign their potential applications.
A Novel Approach to High Performance Elastomer by Using Clay
Authors: Ma Jun , Xiang Ping , Mai Yiu‐Wing , Zhang Li‐Qun 
Published: September 2004

AbstractSummary: A novel method was developed to prepare an exfoliated styrene butadiene rubber (SBR)/clay nanocomposite with a strong interface between the clay layers and the rubber. An exfoliation mechanism was proposed and verified based on X‐ray diffraction (XRD)/transmission electron microscopy (TEM) analyses of the intercalation/exfoliation phenomena after each step of the process. The significant improvements of mechanical properties may give the first evidence that both exfoliation and a strong interface play critical roles in nanoreinforcement.TEM image of a SBR/AA‐clay nanocomposite.imageTEM image of a SBR/AA‐clay nanocomposite.
Sporadic rapid‐onset dystonia–parkinsonism syndrome: Failure of bilateral pallidal stimulation
Authors: Deutschländer Angela , Asmus Friedrich , Gasser Thomas , Steude Ulrich , Bötzel Kai 
Published: September 2004

AbstractWe report on a woman who had a severe sporadic nonprogressive dystonia–parkinsonism syndrome with rapid onset of symptoms at age 21. Secondary causes for dystonia were ruled out. No response to levodopa/carbidopa was seen. The patient fulfilled all diagnostic criteria of rapid‐onset dystonia–parkinsonism, except for autosomal‐dominant inheritance. Bilateral deep brain stimulation of the globus pallidus failed to alleviate her symptoms. © 2004 Movement Disorder Society
Bounding vertex coloring by truncated multistage branch and bound
Authors: Caramia Massimiliano , Dell'Olmo Paolo 
Published: September 2004

AbstractIn this article we design a truncated enumerative algorithm based on branch and bound rules embedded in a multistage scheme that allows iterative visits of subgraphs. The algorithm is designed to find lower bounds on the chromatic number of graphs, and, by means of simple coloring extension rules, it is often capable of finding optimal solutions. In this issue we obtain a very promising result: our algorithm was able to solve benchmarks DSJC125_5, DSJC125_9, DSJC250_1, DSJR500_1c, and DSJR500_5, which had not previously been solved. Furthermore, we show how our method can be employed in finding upper bounds on the chromatic number, and thus, we compare the upper bound–lower bound gaps so obtained with those achieved by known exact algorithms. The comparison highlights that in more than half of the tested benchmarks the gap obtained by our algorithm was lower than that obtained by a recent branch and cut method and by the well‐known DSATUR algorithm. To provide a deeper analysis we finally compare the upper bounds found by the proposed algorithm on the same benchmarks with the best heuristic solutions known in the open literature. Also, in this case, the proposed truncated branch and bound was often able to outperform these heuristic solutions. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(4), 231–242 2004
Impact fracture toughness of polyethylene/polypropylene multilayers
Authors: Moreno Luisa , Leevers Patrick 
Published: September 2004

AbstractIn a number of applications, a brittle polymeric surface layer is deliberately molded onto a tough substrate for decorative or protective purposes. This can increase the susceptibility of the tough polymer to premature failure. Similar problems arise when a surface layer becomes embrittled by environmental effects. Choosing a surface material that has good mechanical properties without having this effect can be difficult. In this work the fracture resistances of two polyethylenes and an ethylene/propylene copolymer, and of symmetrical two‐component multilayers of these polymers, were determined as a function of temperature, using instrumented impact tests. The law of mixtures accounts adequately for the fracture resistance of multilayer structures where there is no mechanical interaction between skin and core. However, it gave misleading results for a structure in which high skin modulus at low temperatures appeared to influence the fracture resistance of the core through a constraint effect. Polym. Eng. Sci. 44:1627–1635, 2004. © 2004 Society of Plastics Engineers.