bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tests of seasonal integration and cointegration in multivariate unobserved component models
Authors: Busetti Fabio 
Published: March 2006

AbstractThis paper considers tests of seasonal integration and cointegration for multivariate unobserved component models. First, the locally best invariant (LBI) test of the null hypothesis of a deterministic seasonal pattern against the alternative of seasonal integration is derived for a model with Gaussian i.i.d. disturbances and deterministic trend. Then the null hypothesis of seasonal cointegration is considered and a test for common nonstationary components at the seasonal frequencies is proposed. The tests are subsequently generalized to account for stochastic trends, weakly dependent errors and unattended unit roots. Asymptotic representations and critical values of the tests are provided, while the finite sample performance is evaluated by Monte Carlo simulation experiments. Finally, the tests are applied to the series of industrial production of the four largest countries of the European Monetary Union. It is found that Germany does not appear to cointegrate with the other countries at most seasonal frequencies, while there seems to exist a common nonstationary seasonal component between France, Italy and Spain. Copyright © 2006 John Wiley & Sons, Ltd.
Sintering‐induced aromatization during n‐heptane reforming on Pt/Al2O3 catalysts
Authors: Susu Alfred A , Ogogo Emmanuel O 
Published: March 2006

AbstractA platinum/alumina catalyst was sintered in oxygen and hydrogen atmospheres using two metal loadings of the catalyst: 0.3% Pt and 0.6% Pt. After sintering, the aromatization selectivity was investigated with the reforming of n‐heptane as the model reaction at a temperature of 500 °C and a pressure of 391.8 kPa. The primary products of n‐heptane reforming on the fresh platinum catalysts were methane and toluene, with subsequent conversion of benzene from toluene demethylation. To induce sintering, the catalysts were treated with oxygen at a flow rate of 60 mL min−1, pressure of 195.9 kPa and temperatures between 500 and 800 °C. The 0.3% Pt/Al2O3 catalyst exhibited enhanced aromatization selectivity at various sintering temperatures while the 0.6% Pt/Al2O3 catalyst was inherently hydrogenolytic. The fact that aromatization was absent on the 0.6% Pt/Al2O3 catalyst was attributed to the presence of surface structures with dimensionality between two and three as opposed to essentially 2‐D structures on the 0.3% Pt/Al2O3 catalyst surface. On the 0.3% Pt/Al2O3 catalyst, the reaction product ranged from only toluene at a 500 °C sintering temperature to predominantly cracked product at a sintering temperature of 650 °C and no reaction at 800 °C. For sintering at about 650 °C, subsequent conversion of n‐heptane was complete and dropped thereafter. The turnover number was observed to change from 0.07 to 2.26 s−1 as the dispersion changed from 0.33 to 0.09. The Koros–Nowark (K–N) test was used to check for the presence of internal diffusional incursions and Boudart's criterion was used for structural sensitivity determination. The K–N test indicated the absence of diffusional resistances while n‐heptane reforming was found to be structure sensitive on the Pt/Al2O3 catalyst. Copyright © 2006 Society of Chemical Industry
Effects of gas flow‐rate and inlet concentration on nitric oxide removal in an autotrophic biofilter
Authors: Chen Jianmeng , Wang Jiade , Ma Jianfeng 
Published: March 2006

AbstractThe effects of inlet gas concentration and gas flow‐rate on the NO elimination process were studied in a laboratory‐scale biofilter and the removal process is discussed. Various pollutant inlet concentrations and gas flow‐rates were tested in the biofilter. The results showed that the removal efficiency increased with increase in the empty bed residence time (EBRT) and finally reached a steady state. The mass transfer process became the limiting step of NO removal when the EBRT was less than 2 min. A removal efficiency of ∼73% was obtained in the biofilter at an inlet concentration of 107.1 mg m−3. The removal efficiency decreased with increase in inlet concentration, whereas the removal capacity increased. The removal process consisted of chemical oxidation and bio‐nitrification in the biofilter. The bioprocess mainly contributed to the removal. Copyright © 2006 Society of Chemical Industry
Optimised immobilisation of microbial lipase on hydrous niobium oxide
Authors: Miranda Michele , da Silva M Lúcia CP , de Castro Heizir F 
Published: March 2006

AbstractThe aim of this work was to establish appropriate conditions for immobilising Candida rugosa lipase on a low‐cost inorganic matrix, hydrous niobium oxide, using a multivariate statistical approach. A 23 full factorial design was employed to determine the effects of support activation with glutaraldehyde (concentration 2.5–4.5%, pH 7–10) and lipase loading (200‐700 U g−1 matrix) on the hydrolytic and synthetic activities of the immobilised derivatives. From the results the following conditions were established: lipase loading of 450 U g−1 matrix and niobium oxide activation with glutaraldehyde at a concentration of 2.5% and pH 8. Under these conditions, high activity recovery (47.21%) and esterification yield (86.90%) were attained. The results also show that hydrous niobium oxide can be a valid alternative to replace high‐cost, commercially available inorganic matrices such as controlled pore silica. Copyright © 2006 Society of Chemical Industry
Treatment of PAH‐contaminated soil by combination of Fenton's reaction and biodegradation
Authors: Palmroth Marja RT , Langwaldt Jörg H , Aunola Tuomo A , Goi Anna , Puhakka Jaakko A , Tuhkanen Tuula A 
Published: March 2006

AbstractA combination of modified Fenton and biological treatment was used to remove polycyclic aromatic hydrocarbons (PAHs) from creosote oil‐contaminated soil. After modified Fenton reaction the toxicity of column leachate and soil to Vibrio fischeri increased. The number of intact bacterial cells and utilisation of PAHs in PAH utilisation microplate assay decreased after modified Fenton reaction. However, bacteria in chemically treated soil utilised PAHs without addition of other carbon sources. The activity of extracellular esterases increased during incubation of modified Fenton‐treated soil. PAH removal in combined chemical oxidation and incubation (43–59%) was higher than in incubation alone (22–30%). Residual H2O2 in soil allowed chemical oxidation of PAHs during incubation. Copyright © 2006 Society of Chemical Industry
Improving lipase production using a perfluorocarbon as oxygen carrier
Authors: Amaral Priscilla FF , Rocha‐Leão Maria Helena M , Marrucho Isabel M , Coutinho João AP , Coelho Maria Alice Z 
Published: March 2006

AbstractPerfluorodecalin, a perfluorocarbon (PFC), was used as an oxygen vector in culture media to enhance lipase productivity by increasing the oxygen availability to Yarrowia lipolytica. The effects of different concentrations of PFC were studied in shake‐flask yeast cultures at 160 and 250 rpm. Higher specific growth rates of Y. lipolytica were found with increasing PFC concentration and agitation rate. Lipase production by Y. lipolytica was enhanced 23‐fold with the addition of 20% (v/v) PFC at 250 rpm. Moreover, it is shown that using PFC and glucose as substrate is more effective in lipase production than the conventional use of olive oil. Copyright © 2006 Society of Chemical Industry
Direct extraction of phenylacetic acid from immobilised enzymatic hydrolysis of penicillin G with cloud point extraction
Authors: Wang Zhilong , Guo Yajing , Bao Da , Qi Hanshi 
Published: March 2006

AbstractThe enzymatic hydrolysis of potassium salt of penicillin G (Pen G) into phenylacetic acid (PAA) and potassium salt of 6‐aminopenicillanic acid (APA) is inhibited not only by the substrate and the product APA but also by the by‐product PAA. The partitioning behaviour of PAA in a cloud point system, a novel two‐phase partitioning system, was determined. Direct extraction of PAA in the process of immobilised penicillin acylase hydrolysis of Pen G without pH control was achieved. Pen G was hydrolysed almost completely and the product APA concentration in the cloud point system was much higher than in the control, suggesting that the cloud point system may be applied as a novel extractive bioreactor for the enzymatic hydrolysis of Pen G. Copyright © 2006 Society of Chemical Industry
Cellular mechanism of estrogen‐induced thymic involution in wall lizard: caspase‐dependent action
Authors: Hareramadas Batchu , Rai Umesh 
Published: March 2006

AbstractThe present study, for the first time in an ectothermic vertebrate, demonstrates the cellular mechanism of estrogen‐induced thymic involution. Ovariectomy in lizards during the preparatory phase of the reproductive cycle resulted in distinct differentiation of cortico‐medullary regions and increase in cellularity, especially in the cortical region. The ovariectomy‐induced changes were reversed following administration of 17β‐estradiol (E2), suggesting a primary role of E2 in causing thymic atrophy. To understand the cellular mechanism of E2‐induced thymic atrophy, in vitro effect of E2 was investigated on thymocyte proliferation and apoptosis. E2 decreased the uptake of tritiated thymidine (3H‐TdR) by thymocytes in a dose‐dependent manner, suggesting that estrogen directly inhibits the thymocyte proliferation. Unlike proliferation, E2 did not have any direct effect on thymocyte apoptosis, as evident by DNA gel electrophoretic, flow cytometric or fluorescence microscopic studies. However, in the presence of thymic epithelial cell‐rich stromal components (TEC), E2 treatment at low or high concentrations resulted in depolarization of plasma membrane, DNA fragmentation and decrease in DNA content. This suggests that E2 indirectly, through TEC‐secreted factors, controls thymocyte apoptosis. Similar result was observed following fluorescence microscopy. The indirect effect of E2 was further ascertained with the findings that E2‐pretreated TEC‐conditioned medium accelerated the thymocyte apoptosis. Nevertheless, exposure of thymocytes to E2 was seen to be inevitable for the apoptotic action of TEC‐secreted paracrine factors. In the presence of TEC, a positive reaction for caspase‐3, ‐7 and ‐9 and enzyme substrate, poly(ADP‐ribose) polymerase (PARP) in response to E2 suggests the caspase‐dependent thymocyte apoptosis in the wall lizard Hemidactylus flaviviridis. Further, E2 was shown to act through genomic pathway, since the receptor antagonist tamoxifen and transcription/translation inhibitors blocked its apoptotic action. Interestingly, the apoptotic effect of E2 was effectively decreased by progesterone. J. Exp. Zool. 305A, 2006. © 2006 Wiley‐Liss, Inc.
Use of nonviral promoters in adenovirus‐mediated gene therapy: reduction of lysosomal storage in the aspartylglucosaminuria mouse
Authors: Virta Salli , Rapola Juhani , Jalanko Anu , Laine Minna 
Published: March 2006

AbstractBackgroundAspartylglucosaminuria (AGU) is a lysosomal storage disease with severe neurodegenerative clinical features resulting from the deficiency of lysosomal aspartylglucosaminidase (AGA). The AGU knockout mouse is a good model to test different therapy strategies, as it mimics well the human pathogenesis of the disease exhibiting storage vacuoles in all tissues. In this study we investigated the efficiency of nonviral promoters in adenovirus‐mediated gene therapy.MethodsThe deficient corrective enzyme, AGA, was expressed using two tissue‐specific promoters, neuron‐specific enolase (NSE), astrocyte‐specific (GFAP) and the endogenous AGA promoter. An intrastriatal injection site was chosen due to its wide connections in the central nervous system (CNS). The expression of AGA was analyzed 1 week, 2 weeks, 4 weeks, 2 months and 4 months after the virus injection by lysosomal AGA‐specific immunostaining. A correction of the lysosomal storage in the brain of treated mice was also studied using toluidine blue stained thin sections.ResultsThe overexpressed AGA enzyme was detected in addition to the injection site, also in the ipsilateral parietal cortex indicating migration of AGA in the brain tissue. Duration of AGA expression was markedly longer with all the viruses used compared to the green fluorescent protein (GFP) expression driven by the viral cytomegalovirus (CMV) promoter. In most animals the storage was decreased by at least 50% as compared to untreated AGU mouse brains. Remarkably, >90% correction of storage at the ipsilateral cortex was found with the NSE promoter at 4 weeks and 2 months after injection. Additionally, partial clearance of storage was demonstrated also in the contralateral side of the brain.ConclusionsThese data implicate that tissue‐specific promoters are especially useful in virus‐mediated gene therapy aiming at long‐term gene expression. Copyright © 2006 John Wiley & Sons, Ltd.
VEGF 164 gene transfer by electroporation improves diabetic sensory neuropathy in mice
Authors: Murakami Tatsufumi , Arai Makiko , Sunada Yoshihide , Nakamura Akihiro 
Published: March 2006

AbstractBackgroundDiabetic neuropathy is the most common cause of peripheral neuropathy and a serious complication of diabetes. Vascular endothelial growth factor (VEGF) stimulates angiogenesis and has neurotrophic and neuroprotective activities. To examine the efficiency of VEGF 164 electro‐gene therapy for neuropathy, intramuscular VEGF 164 gene transfer by electroporation was performed to treat sensory neuropathy in diabetic mice.MethodsVEGF 164 was overexpressed in the tibial anterior (TA) muscles of streptozotocin‐induced diabetic mice with hypoalgesia, using a VEGF 164 plasmid injection with electroporation. From 2 weeks after electro‐gene transfer, the nociceptive threshold was measured weekly using the paw‐pressure test. The TA muscles, sciatic nerve, liver and spleen were histochemically examined at 4 weeks after electro‐gene transfer.ResultsTwo weeks after electro‐gene transfer into the bilateral TA muscles, the elevated nociceptive threshold was decreased to a normal level in all treated mice. Improvement of the hypoalgesia continued for 14 weeks. When the VEGF 164 plasmid was injected with electroporation into a unilateral TA muscle, recovery from hypoalgesia was observed in not only the ipsilateral hindpaw, but also the contralateral one, suggesting that VEGF circulates in the blood. No increase in the number of endoneurial vessels in the sciatic nerve was found in the VEGF 164 plasmid‐electroporated mice.ConclusionsThese findings suggest that VEGF 164 electro‐gene therapy completely recovered the sensory deficits, i.e. hypoalgesia, in the diabetic mice through mechanisms other than angiogenesis in the endoneurium of the peripheral nerve, and may be useful for treatment for diabetic sensory neuropathy in human subjects. Copyright © 2006 John Wiley & Sons, Ltd.
Therapeutic level of functional human alpha 1 antitrypsin (hAAT) secreted from murine muscle transduced by adeno‐associated virus (rAAV1) vector
Authors: Lu Yuanqing , Choi Young‐Kook , Campbell‐Thompson Martha , Li Chengwen , Tang Qiushi , Crawford James M. , Flotte Terence R. , Song Sihong 
Published: March 2006

AbstractAlpha 1 antitrypsin (AAT) is a serine proteinase inhibitor (serpin). One well‐known function of this protein is to inactivate neutrophil elastase and other neutrophil‐derived proteinases, and prevent the destruction of pulmonary extracellular matrix. Deficiency of AAT can cause emphysema due to degradation of interstitial elastin by elastase. The majority of circulating AAT is secreted from the liver. Muscle‐directed gene therapy using recombinant adeno‐associated virus 2 (rAAV2) vectors has been tested to increase the serum levels of AAT. However, inefficient transduction of rAAV2 vector makes it difficult to reach therapeutic levels of AAT in clinical trials and it remains unclear as to whether muscle‐secreted AAT is functional. In the present study, we evaluated five serotypes (1, 2, 3, 4, and 5) of rAAV vectors for transduction efficiency in mouse muscle. Results from these studies showed that rAAV1 is the most efficient vector among these serotypes and mediated at least 100‐fold higher levels of AAT secretion than the rAAV2 vector. Western blot analysis showed that this murine muscle‐secreted human AAT (hAAT) formed a complex with human neutrophil elastase in a dose‐dependent manner. An anti‐elastase activity assay showed that murine muscle‐secreted hAAT inhibited elastase with equal capacity as hAAT purified from plasma. These results provide strong support for the functionality of AAT in ongoing clinical studies of muscle‐directed AAT gene therapy. Copyright © 2006 John Wiley & Sons, Ltd.
Upper cervical cord area in early relapsing‐remitting multiple sclerosis: Cross‐sectional study of factors influencing cord size
Authors: Rashid Waqar , Davies Gerard R. , Chard Declan T. , Griffin Colette M. , Altmann Dan R. , Gordon Ros , Kapoor Raju , Thompson Alan J. , Miller David H. 
Published: March 2006

AbstractPurposeTo determine whether the upper cervical cord area (UCCA) is influenced by disease effect in early relapsing‐remitting multiple sclerosis (MS), using statistical modeling to account for potential covariates.Materials and MethodsA cohort of 39 patients were studied cross‐sectionally within three years of first symptom onset (median disease duration = 1.6 years) and compared with 26 healthy controls. The UCCA was measured from axial reconstructions of three‐dimensional T1‐weighted scans with automated detection of the edge of the cord. Statistical analysis adjusted for factors such as total intracranial volume (TICV) and gender. Clinical correlations, in particular those thought likely to be related to cord pathology, were also investigated.ResultsNo significant disease effect was noted on UCCA (P = 0.685), although there was borderline evidence of a lower UCCA in patients with symptoms of bowel or bladder disturbance (P = 0.043). A strong association was noted between UCCA and TICV (r = 0.558; P ≤ 0.001), and there was a trend for females to have a smaller UCCA (P = 0.062). The latter finding appeared to reflect a gender‐related difference in TICV (P ≤ 0.001).ConclusionAtrophy of the upper cervical cord is not readily apparent in most patients early in the course of relapsing‐remitting MS. In evaluations of disease‐related changes in the UCCA in cross‐sectional studies, TICV and gender should be considered as potentially confounding covariates. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
fMRI studies of sensitivity and habituation effects within the auditory cortex at 1.5 T and 3 T
Authors: Rabe Kerstin , Michael Nikolaus , Kugel Harald , Heindel Walter , Pfleiderer Bettina 
Published: March 2006

AbstractPurposeTo assess habituation effects in relation to field strength by fMRI at 1.5 vs. 3.0 T within the auditory cortex of healthy subjects.Materials and MethodsfMRI experiments were performed on 19 healthy subjects at 1.5 T (N = 12) and 3 T (N = 12). The auditory cortex was stimulated binaurally by digitally generated pulsed (ν = 5 Hz) 800 Hz sine tones with three alternating on and off periods.ResultsThe mean activation after stimulation (4.4% ± 1.2% (1.5 T) and 5.3% ± 2.3% (3 T)) and number of activated pixels (96.7 ± 49.8 (1.5 T) and 139.9 ± 101 (3 T)) were higher at 3 T compared to 1.5 T; however, that difference did not reach statistical significance. A characteristic signal decay with repeated stimuli was revealed at both 1.5 and 3 T, and the response to the second and third stimulation blocks was significantly lower compared to the first. The habituation pattern was the same, independently of field strength and age.ConclusionThe mean activation and number of pixels were only modestly higher at 3 T, probably due to higher physiologic noise and higher local macroscopic susceptibility gradients within the temporal lobes at 3 T. Our data reveal that measured auditory habituation is independent of field strength, and data obtained at two different field strengths do not differ fundamentally in this context. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
On the transmission properties of left‐handed microstrip lines implemented by complementary split rings resonators
Authors: Gil M. , Bonache J. , Gil I. , García‐García J. , Martín F. 
Published: March 2006

AbstractIn this paper, the transmission properties of left‐handed microstrip lines implemented by etching complementary split rings resonators (CSRRs) and capacitive gaps in the ground plane and conductor strip, respectively, are investigated. To this end, we make use of the lumped element equivalent circuit model of the structure, from which an accurate analysis is carried out, and the influence of the main electrical parameters on the transmission properties is pointed out through electrical simulations. Aspects such as bandwidth and in‐band ripple control are discussed in detail. The influence of the geometrical parameters is also discussed and interpreted to the light of the equivalent circuit model. From the results obtained, there are inferred design guidelines that are suitable for the design of metamaterial transmission lines subjected to specifications. Copyright © 2006 John Wiley & Sons, Ltd.
Wave scattering by metamaterial wedges and interfaces
Authors: Sukhorukov Andrey A. , Shadrivov Ilya V. , Kivshar Yuri S. 
Published: March 2006

AbstractWe outline specific features of numerical simulations of metamaterial wedges and interfaces. We study the effect of different positioning of a grid in the Yee method, which is necessary to obtain consistent convergence in modelling of interfaces with metamaterials characterized by negative dielectric permittivity and negative magnetic permeability. We demonstrate however that, in the framework of the continuous‐medium approximation, wave scattering on the wedge may result in a resonant excitation of waves with infinitely large spatial frequencies, leading to non‐convergence of the simulation results that depend on the discretization step. Copyright © 2006 John Wiley & Sons, Ltd.
Wave properties of computational TLM models of metamaterials with negative refractive index
Authors: Hoefer Wolfgang J. R. , Du Huilian , So Poman P. M. 
Published: March 2006

AbstractWe derive and compare the wave properties of transmission‐line‐based negative refractive index metamaterials and their transmission line matrix (TLM) models. The TLM networks are computational replica of reactively loaded periodic structures that support backward waves and constitute artificial media with negative refractive index. After a brief review of the TLM algorithms for three types of nodes, namely the 2D Shunt Node, the 3D Expanded (or Distributed) Node, and the 3D Symmetrical Condensed Node, we formulate and solve the general dispersion equations in 2D and 3D metamaterials based on these nodes. We compare the results with the dispersion properties of both idealized homogeneous metamaterials and of L‐C loaded periodic transmission line structures that have the same cell size as their computational TLM counterparts. Copyright © 2006 John Wiley & Sons, Ltd.