bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ratio estimators in adaptive cluster sampling
Authors: Dryver Arthur L. , Chao Chang‐Tai 
Published: February 2007

AbstractIn most surveys data are collected on many items rather than just the one variable of primary interest. Making the most use of the information collected is a issue of both practical and theoretical interest. Ratio estimates for the population mean or total are often more efficient. Unfortunately, ratio estimation is straightforward with simple random sampling, but this is often not the case when more complicated sampling designs are used, such as adaptive cluster sampling. A serious concern with ratio estimates introduced with many complicated designs is lack of independence, a necessary assumption. In this article, we propose two new ratio estimators under adaptive cluster sampling, one of which is unbiased for adaptive cluster sampling designs. The efficiencies of the new estimators to existing unbiased estimators, which do not utilize the auxiliary information, for adaptive cluster sampling and the conventional ratio estimation under simple random sampling without replacement are compared in this article. Related result shows the proposed estimators can be considered as a robust alternative of the conventional ratio estimator, especially when the correlation between the variable of interest and the auxiliary variable is not high enough for the conventional ratio estimator to have satisfactory performance. Copyright © 2007 John Wiley & Sons, Ltd.
GIS‐assisted modelling for debris flow hazard assessment based on the events of May 1998 in the area of Sarno, Southern Italy: Part I. Maximum run‐out
Authors: Toyos G. , Dorta D. Oramas , Oppenheimer C. , Pareschi M. T. , Sulpizio R. , Zanchetta G. 
Published: February 2007

AbstractBased on the debris flow events that occurred in May 1998 in the area of Sarno, Southern Italy, this paper presents an approach to simulate debris flow maximum run‐out. On the basis of the flow source areas and an average thickness of 1·2 m of the scarps, we estimated debris flow volumes of the order of 104 and 105 m3. Flow mobility ratios (ΔH/L) derived from the x, y, z coordinates of the lower‐most limit of the source areas (i.e. apex of the alluvial fan) and the distal limit of the flows ranged between 0·27 and 0·09. We performed regression analyses that showed a good correlation between the estimated flow volumes and mobility ratios. This paper presents a methodology for predicting maximum run‐out of future debris flow events, based on the developed empirical relationship. We implemented the equation that resulted from the calibration as a set of GIS macros written in Visual Basic for Applications (VBA) and running within ArcGIS. We carried out sensitivity analyses and observed that hazard mapping with this methodology should attempt to delineate hazard zones with a minimum horizontal resolution of 0·4 km. The developed procedure enables the rapid delineation of debris flow maximum extent within reasonable levels of uncertainty, it incorporates sensitivities and it facilitates hazard assessments via graphic user interfaces and with modest computing resources. Copyright © 2007 John Wiley & Sons, Ltd.
Thymus piperella (L.) essential oil: an alternative in the treatment of diarrhoea
Authors: Martí D. , Pérez‐Gracia MT , Blanquer A. , Villagrasa V. , Sanahuja M.A. , Moreno L. 
Published: February 2007

AbstractThymus piperella (L.) (family Labiatae) is an endemic taxon found in eastern Spain. The aerial part of T. piperella is principally used for culinary purposes, to flavour stuffings, sauces, pickles, stews, soups, etc. Moreover, it has traditionally been used to conserve and soften olives, and in the distillation of an alcoholic beverage named ‘herbero’, which is typical in the south of Valencia and north of Alicante, and whose digestive properties are well documented. Despite it being a popular plant in this region, to date T. piperella (L.) has not been pharmacologically described. Pharmacological assays have been carried out on the essential oil of Thymus piperella (L.) leaves. The oil was shown to be innocuous according to the acute oral toxicity test and exhibited antispasmodic action that significantly inhibited the contractions induced by acetylcholine in the isolated rat ileum in a concentration‐dependent manner. Essential oil from Thymus piperella (L.) leaves was active against Staphylococcus aureus, Escherichia coli, Candida albicans, Streptococcus pyogenes and Mycobacterium phlei. Such antimicrobial activity would explain the popular use of this plant in the conservation of olives. Moreover, as the inhibition of contractile overactivity of the ileum (antispasmodic action) is the basis of the treatment of some gastrointestinal disorders, such as diarrhoea, and as many diarrhoea‐causing diseases are associated with intestinal infection, Thymus piperella essential oil could constitute an alternative therapy in such cases. In this way, this species, so commonly used in the Mediterranean kitchen, may be beneficial to the health in more ways than one. Copyright © 2007 John Wiley & Sons, Ltd.
Coexistence of Sexual and Parthenogenetic Artemia Populations in Lake Urmia and Neighbouring Lagoons
Authors: Agh Naser , Abatzopoulos Theodore J. , Kappas Ilias , Van Stappen Gilbert , Razavi Rouhani Seyed M. , Sorgeloos Patrick 
Published: February 2007

AbstractWe studied the Artemia populations existing in Lake Urmia (north‐western Iran), one of the largest habitats of Artemia in the world, in order to settle the long‐standing controversy over the sexual status of the endemic Artemia populations. Experiments were carried out in the laboratory and in the field. Cysts, collected from different sites of the lake and peripheral lagoons, were hatched and cultured to adults in the laboratory. Adult sexual and parthenogenetic animals were isolated and newly hatched nauplii from them were cultured to maturity in different salinities, ranging from 15–80 ppt. Survival levels and percentage of animals attaining adulthood were measured over a period of 30 days. In the field experiment, cysts taken from Lake Urmia were hatched and the resulting nauplii were inoculated into six earthen ponds (80–140 ppt) constructed in the vicinity of the lake. Population composition in each pond was determined over a period of two years. Results indicated that both sexual and parthenogenetic Artemia coexist in Lake Urmia. While the lake itself is dominated by sexual Artemia, the asexual populations were found to be restricted to particular areas in or near the lake. Artemia appearing seasonally in the lagoons adjacent to the lake were exclusively parthenogenetic. Parthenogens could grow, mature and reproduce at very low salinities (15–33 ppt), whereas higher salinities (above 50 ppt) were required for A. urmiana to attain sexual maturity. We consider salinity to be a major abiotic factor determining the distribution of these sexually different populations within and outside the lake. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exposure to mixtures of endosulfan and zineb induces apoptotic and necrotic cell death in SH‐SY5Y neuroblastoma cells,in vitro
Authors: Jia Zhenquan , Misra Hara P. 
Published: February 2007

AbstractA number of epidemiological studies have demonstrated a strong association between the incidence of Parkinson's disease and pesticide exposure. Earlier it was demonstrated that exposure to the pesticides endosulfan and zineb, alone and in combination, caused neurodegenerationin vivo. It was hypothesized that these pesticides cause neurotoxicity, in part, by enhancing apoptotic cell death. SH‐SY5Y human neuroblastoma cells, which retain a catecholaminergic phenotype, were exposed to endosulfan, zineb or a combination of these chemicals,in vitro. For mixture studies, concentrations of pesticides (100 µmeach) were chosen based on LC25(lethal concentration) that would result in minimum cell death. Exposure to a mixture of pesticides exhibited significantly (P≤ 0.05) higher toxicity than each one alone. Both pesticides were found to cause apoptotic cell death that was concentration (50–400 µm) dependent. A flow cytometric (7‐aminoactinomycin D) assay was used to distinguish live, early apoptotic and late apoptotic/necrotic populations. Exposure to mixtures of the pesticides enhanced both early apoptosis and late apoptosis/necrosis compared with either chemical alone. Visual evaluation using a DNA ladder assay and a fluorescence Annexin V/PI assay confirmed the contribution of both apoptotic and necrotic processes. These findings suggest that the cytotoxicity of endosulfan and zineb, both individually and in mixtures, is associated with the occurrence of early and late apoptotic/necrotic processes in SH‐SY5Y human neuroblastoma cells and support the contention that pesticide‐induced neuronal cell death leading to neurodegenerative disease may, at least in part, be associated with early and late apoptosis of dopaminergic neurons. Copyright © 2007 John Wiley & Sons, Ltd.
Entry of two new asymmetric bispyridinium oximes (K‐27 and K‐48) into the rat brain: comparison with obidoxime
Authors: Lorke D. E. , Hasan M. Y. , Nurulain S. M. , Sheen R. , Kuča K. , Petroianu G. A. 
Published: February 2007

AbstractIn the search for new oximes with higher reactivation potency and a broader spectrum, K‐27 and K‐48, have recently been synthesized. To test if their superior efficacy was related to better penetration across the blood–brain barrier, their brain entry was compared with that of obidoxime, when administered either alone or after the organophosphate paraoxon (POX). Rats received 50 µmol obidoxime, K‐27 or K‐48, either alone or in addition to 1 µmol POX. Oxime concentrations at various points in time in brain and plasma were measured using HPLC. The obidoxime Cmax in brain was 1.3% of the plasma Cmax when injected alone, and 1.5% when injected following POX. The ratio of the area under the curve (AUC) brain to plasma for obidoxime was around 6%, irrespective of whether it was administered alone or after POX. For K‐27, Cmax (brain) was 0.6% of Cmax (plasma) when injected alone, and 0.7% when injected after POX (no significant difference). The AUC (brain) was 2% of AUC (plasma) for both K‐27 groups. K‐48, when injected alone reached 1.4% of Cmax (plasma) in the brain and 1.2% of Cmax (plasma), when injected following POX. The AUC (brain) was 5% of the AUC (plasma), both when K‐48 was administered alone and in combination with POX. Entry of all three oximes into the brain is minimal and cannot explain the better therapeutic efficacy of K‐27 and K‐48. As already observed for pralidoxime, injection of POX before oxime administration had no influence upon penetration across the blood–brain barrier. Copyright © 2007 John Wiley & Sons, Ltd.
Hill‐climbing to Pasch valleys
Authors: Heap Danny , Danziger Peter , Mendelsohn Eric 
Published: February 2007

AbstractExhaustive enumeration of Steiner Triple Systems is not feasible, due to the combinatorial explosion of instances. The next‐best hope is to quickly find a sample that is representative of isomorphism classes. Stinson's Hill‐Climbing algorithm [20] is widely used to produce random Steiner Triple Systems, and certainly finds a sample of systems quickly, but the sample is not uniformly distributed with respect to the isomorphism classes of STS with ν ≤ 19, and, in particular, we find that isomorphism classes with a large number of Pasch configurations are under‐represented. No analysis of the non‐uniformity of the distribution with respect to isomorphism classes or the intractability of obtaining a representative sample for ν > 19 is known. We also exhibit a modification to hill‐climbing that makes the sample if finds closer to the uniform distribution over isomorphism classes in return for a modest increase in running time. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 405–419, 2007
Ascorbate transport by primary cultured neurons and its role in neuronal function and protection against excitotoxicity
Authors: Qiu Shenfeng , Li Liying , Weeber Edwin J. , May James M. 
Published: February 2007

AbstractNeurons maintain relatively high intracellular concentrations of ascorbic acid, which is achieved primarily by the activity of the sodium‐dependent vitamin C transporter SVCT2. In this work, we studied the mechanisms by which neuronal cells in culture transport and maintain ascorbate as well as whether this system contributes to maturation of neuronal function and cellular defense against oxidative stress and excitotoxic injury. We found that the SVCT2 helps to maintain high intracellular ascorbate levels, normal ascorbate transport kinetics, and activity‐dependent ascorbate recycling. Immunocytochemistry studies revealed that SVCT2 is expressed primarily in the axons of mature hippocampal neurons in culture. In the absence of SVCT2, hippocampal neurons exhibited stunted neurite outgrowth, less glutamate receptor clustering, and reduced spontaneous neuronal activity. Finally, hippocampal cultures from SVCT2‐deficient mice showed increased susceptibility to oxidative damage and N‐methyl‐D‐aspartate‐induced excitotoxicity. Our results revealed that maintenance of intracellular ascorbate as a result of SVCT2 activity is crucial for neuronal development, functional maturation, and antioxidant responses. © 2007 Wiley‐Liss, Inc.
The influence of a pulsating electric field on selenium accumulation in Kluyveromyces marxianus cells
Authors: Pankiewicz Urszula , Jamroz Jerzy 
Published: February 2007

AbstractK. marxianus was cultivated under conditions of PEF (pulse electric field) action and a selenium source. The culture duration after which cells were treated with PEF, the field exposure time and the selenium concentration in the medium were all optimized. Optimization of culture duration caused a 33% increase in selenium accumulation in cells as compared to the control with no PEF treatment. The highest selenium accumulation – about 167 μg/g dry mass (DM) – was recorded after 3‐minute PEF treatment of 16‐hour culture. A roughly two‐fold increase in selenium content was achieved after optimization of culture duration and PEF treatment time. Finding the optimum selenium concentration in the medium brought about a 13‐fold increase of selenium accumulation in the cells of K. marxianus. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Production of L(+) lactic acid from cassava starch hydrolyzate by immobilized Lactobacillus delbrueckii
Authors: John Rojan Pappy , Nampoothiri Kesavan Madhavan , Pandey Ashok 
Published: February 2007

AbstractA process based on low cost production media was developed for fermentative production of L(+) lactic acid. Various process parameters were optimized for the production of L(+) lactic acid from cassava starch hydrolyzate‐based medium by immobilized whole cells of Lactobacillus delbrueckii. The parameters considered for optimization were concentration of alginate and CaCl2, initial cell concentration, curing time, bead size and incubation time of fermentation. Reusability of immobilized cells up to six batches was observed without any decline in lactate production. Lactate yield for L. delbrueckii was 0.93 g lactic acid × g–1 reducing sugar with a production rate of 0.33 g × l–1 × h–1. A column bioreactor packed with immobilized L. delbrueckii was run for three weeks in a continuous mode with a lactate yield of 0.75–0.95 g lactic acid × g–1 reducing sugar with an average production rate of 0.48 g × l–1 × h–1. The study revealed that agro residues like cassava bagasse could be used as source material for developing a low cost technology for lactate production. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental determination of threshold dose in photodynamic therapy in normal rat liver
Authors: Ferreira J , Moriyama L T , Kurachi C , Sibata C , Castro e Silva Jr. O , Zucoloto S , Bagnato V S 
Published: February 2007

Using normal rat liver we investigated the depth of necrosis induced by photodynamic therapy when different light doses and photosensitizer (Photogem®) concentrations. All experiments were done with a fluence rate of 250 mW/cm2. Photosensitizer concentration was varied from 1.0, 1.5, 2.0, and 5.0 mg/kg of body weight and it was administered through the left tail vein. For each photosensitizer concentration the light dose was varied from 10, 50, 100, 150, and 200 J/cm2. Each experimental point was done using five animals. The depth of necrosis analysis allows us to determine the threshold dose and compare its value with the existent results in the literature. Our result suggested a value about 3 times higher than the conventionally adopted value. It indicates the dependence of such value with the employed concentration photosensitizer.
The use of simple models to understand basic features of the PDT (Photodynamic Therapy) may contribute to the solid establishment of dosimetry in PDT enhancing its use in the clinical management of cancers and others lesions.
Bladder inhibition or voiding induced by pudendal nerve stimulation in chronic spinal cord injured cats
Authors: Tai Changfeng , Wang Jicheng , Wang Xianchun , de Groat William C. , Roppolo James R. 
Published: February 2007

AbstractAimsTo investigate pudendal‐to‐bladder spinal reflexes in chronic spinal cord injured (SCI) cats induced by electrical stimulation of the pudendal nerve.MethodsBladder inhibition or voiding induced by pudendal nerve stimulation at different frequencies (3 or 20 Hz) was studied in three female, chronic SCI cats under α‐chloralose anesthesia.ResultsVoiding induced by a slow infusion (2–4 ml/min) of saline into the bladder was very inefficient (voiding efficiency = 7.3% ± 0.9%). Pudendal nerve stimulation at 3 Hz applied during the slow infusion inhibited reflex bladder activity, and significantly increased bladder capacity to 147.2 ± 6.1% of its control capacity. When the 3‐Hz stimulation was terminated, voiding rapidly occurred and the voiding efficiency was increased to 25.4 ± 6.1%, but residual bladder volume was not reduced. Pudendal nerve stimulation at 20 Hz induced large bladder contractions, but failed to induce voiding during the stimulation due to the direct activation of the motor pathway to the external urethral sphincter. However, intermittent pudendal nerve stimulation at 20 Hz induced post‐stimulus voiding with 78.3 ± 12.1% voiding efficiency. The voiding pressures (39.3 ± 6.2 cmH2O) induced by the intermittent pudendal nerve stimulation were higher than the voiding pressures (23.1 ± 1.7 cmH2O) induced by bladder distension. The flow rate during post‐stimulus voiding induced by the intermittent pudendal nerve stimulation was significantly higher (0.93 ± 0.04 ml/sec) than during voiding induced by bladder distension (0.23 ± 0.07 ml/sec).ConclusionsThis study indicates that a neural prosthetic device based on pudendal nerve stimulation might be developed to restore micturition function for people with SCI. Neurourol. Urodynam. 26:570–577, 2007. © 2007 Wiley‐Liss, Inc.
Magnetization transfer effects on the efficiency of flow‐driven adiabatic fast passage inversion of arterial blood
Authors: Hernandez‐Garcia Luis , Lewis David P. , Moffat Bradford , Branch Craig A. 
Published: February 2007

AbstractContinuous arterial spin labeling experiments typically use flow‐driven adiabatic fast passage inversion of the arterial blood water protons. In this article, we measure the effect of magnetization transfer in blood and how it affects the inversion label. We use modified Bloch equations to model flow‐driven adiabatic inversion in the presence of magnetization transfer in blood flowing at velocities from 1 to 30 cm/s in order to explain our findings. Magnetization transfer results in a reduction of the inversion efficiency at the inversion plane of up to 3.65% in the range of velocities examined, as well as faster relaxation of the arterial label in continuous labeling experiments. The two effects combined can result in inversion efficiency reduction of up to 8.91% in the simulated range of velocities. These effects are strongly dependent on the velocity of the flowing blood, with 10 cm/s yielding the largest loss in efficiency due to magnetization transfer effects. Flowing blood phantom experiments confirmed faster relaxation of the inversion label than that predicted by T1 decay alone. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and characterization of the new silane‐based antioxidant containing 2,6‐di‐tert‐butylphenolic stabilizing moiety
Authors: Nedelčev T. , Krupa I. , Csomorová K. , Janigová I. , Rychlý J. 
Published: February 2007

AbstractA new kind of antioxidant 4‐[(3‐(triethoxysilyl)propylimino)methyl]‐2,6‐di‐tert‐butylphenol consisting of an alkoxysilyl group and a 2,6‐di‐tert‐butylphenol stabilizing moiety was synthesized and tested in isotactic poly(propylene). FT‐IR, 1H‐NMR, 13C‐NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) were used for characterization of synthesized silane stabilizer. The derivative of 4‐[(3‐(triethoxysilyl)propylimino)methyl]‐2,6‐di‐tert‐butylphenol was also prepared by the condensation reaction using the sol‐gel process. Stabilizing activity of the new silane stabilizer and its condensed form was verified by chemiluminiscence and thermogravimetry measurements in oxygen atmosphere and compared with conventional 2,6‐di‐tert‐butyl‐4‐methyl‐ phenol as well as with the conventional stabilizing system based on the mixture of Irganox 1010/Irgafos168 (weight ratio of 1:2). Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of new polyfluorene copolymers with a comonomer containing triphenylamine units and their applications in white‐light‐emitting diodes
Authors: Lee Sang Kyu , Ahn Taek , Cho Nam Sung , Lee Jeong‐Ik , Jung Young Kwan , Lee Jonghee , Shim Hong Ku 
Published: February 2007

AbstractNovel conjugated polyfluorene copolymers, poly[9,9‐dihexylfluorene‐2,7‐diyl‐co‐(2,5‐bis(4′‐diphenylaminostyryl)‐phenylene‐1,4‐diyl)]s (PGs), have been synthesized by nickel(0)‐mediated polymerization from 2,7‐dibromo‐9,9‐dihexylfluorene and 1,4′‐dibromo‐2,5‐bis(4‐diphenylaminostyryl)benzene with various molar ratios of the monomers. Because of the incorporation of triphenylamine (TPA) moieties, PGs exhibit much higher HOMO levels than the corresponding polyfluorene homopolymers and are able to facilitate hole injection into the polymer layer from the anode electrode in light‐emitting diodes. Conventional polymeric light‐emitting devices with the configuration ITO/PEDOT:PSS/polymer/Ca/Al have been fabricated. A light‐emitting device produced with one of the PG copolymers (PG10) as the emitting layer exhibited a voltage‐independent and stable bluish‐green emission with color coordinates of (0.22, 0.42) at 5 V. The maximum brightness and current efficiency of the PG10 device were 3370 cd/m2 (at 9.6 V) and 0.6 cd/A, respectively. To realize a white polymeric light‐emitting diode, PG10 as the host material was blended with 1.0 wt % of a red‐light‐emitting polymer, poly[9,9‐dioctylfluorene‐2,7‐diyl‐alt‐2,5‐bis(2‐thienyl‐2‐cyanovinyl)‐1‐(2′‐ethylhexyloxy)‐4‐methoxybenzene‐5′,5′‐diyl] (PFR4‐S), and poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV). The device based on PG10:PFR4‐S showed an almost perfect pure white electroluminescence emission, with Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.36) at 8 V; for the PG10:MEH‐PPV device, the CIE coordinates at this voltage were (0.30, 0.40) with a maximum brightness of 1930 cd/m2. Moreover, the white‐light emission from the PG10:PFR4‐S device was stable even at different driving voltages and had CIE coordinates of (0.34, 0.36) at 6 V and (0.31, 0.35) at 10 V. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1199–1209, 2007