bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Reoxidation on the Grain‐Boundary Acceptor‐State Density of Reduced BaTiO3 Ceramics
Authors: Ho In‐Chyuan , Fu Shen‐Li
Published: April 2005

To investigate the effect of reoxidation on the grain‐boundary acceptor‐state density of reduced barium titanate, n‐doped BaTiO3 ceramics are sintered in a reducing atmosphere (2% H2+ 98% N2) and then annealed in oxygen. After annealing at 1150°C for different times, the experimental results show a relationship between temperature‐averaged acceptor‐state density and annealing time as Ns=NsoBt1/n with n between 2 and 3. An inherent acceptorstate density Nso= 4.25 × 1012 cm−2 is obtained with an increase rate B= 4.8 × 1012 cm−2. min−1/3, when n reaches 3. The inherent grain‐boundary acceptor states in the reduced n‐doped BaTiO3 ceramics are believed not due to adsorbed oxygen ions.
Fibrous Monolithic Ceramics: II, Flexural Strength and Fracture Behavior of the Silicon Carbide/Graphite System
Authors: Baskaran Suresh , Halloran John W.
Published: April 2005

The fibrous monolith microstructure consists of high aspect ratio polycrystalline cells of SiC separated by thin cell boundaries containing graphite. The SiC/100% graphite fibrous monolith has noncatastrophic fracture behavior, is damage tolerant, and is notch insensitive. The failure process is characterized by fracture along weak graphite cell boundaries. The room‐temperature flexural strength is 300–350 MPa. The estimated shear strength along the graphite cell boundaries is ∼ 15 MPa. Increasing the strength of the cell boundary by additions of SiC (40–60 vol%) results in a monolithic SiC material showing brittle fracture behavior but retaining damage tolerance. Strength and fracture behavior are also influenced by cell texture and orientation.
Model for Toughness Curves in Two‐Phase Ceramics: I, Basic Fracture Mechanics
Authors: Lawn Brian R. , Padture Nitin P. , Braun Linda M. , Bennison Stephen J.
Published: April 2005

A fracture mechanics model is presented for the toughening of ceramics by bridging from second‐phase particles, resulting in toughness curve (T ‐curve) behavior. It is assumed that the second‐phase particles are in a state of residual thermal expansion dilatational mismatch relative to the matrix. In the long‐crack region, these stresses augment frictional sliding stresses at the interphase boundaries, enhancing the crack resistance; in the short‐crack region, the same stresses drive the crack, diminishing the crack resistance. The principal manifestation of these countervailing influences is a reduced sensitivity of strength to initial flaw size, i.e., an increased flaw tolerance. In seeking to incorporate these key physical elements, our model opts for mathematical simplicity by assuming uniformly distributed stresses in two bridging domains: in the first, at small crack‐wall separations, a constant opening stress; in the second, at larger separations, a constant closing stress. The uniform crack‐plane distributions allow for simple closed‐form solutions of the crack K‐field equations, and thence an analytical formulation for the T‐curve. Indentation‐strength data on a “reference” Al2O3/Al2TiO5 ceramic composite are used to demonstrate the main theoretical predictions and to calibrate essential parameters in the T‐curve formulation. The utility of the model as a route to microstructural design is addressed in Part II.
Combined Mode I and Mode II Fracture of Monolithic Ceramics
Authors: Tikare Veena , Choi Sung R.
Published: April 2005

The mode I, mode II, and combined mode I–mode II fracture behaviors of a coarse‐grained silicon nitride, a fine‐grained silicon nitride, and an alumina were investigated. These ceramics were fractured from two types of fracture initiating flaws: small surface flaws and large single edge precracks. The small surface flaws were introduced by Knoop indentation in flexural samples at various angles to the tensile stress direction and fractured in four‐point bending. The samples with large precracks were fractured in the asymmetric four‐point‐bend geometry. The mixed‐mode fracture toughness values obtained from the two flaw configurations were in good agreement with each other. All three ceramics displayed very similar mixed‐mode fracture behavior, although their microstructures were not similar. Comparison of experimental data to mixed‐mode fracture theories revealed that the minimum strain energy density theory best described the mixed‐mode fracture behavior of all three ceramics.
Effect of Powder Surface Modifications on the Properties of Silicon Nitride Ceramics
Authors: Natansohn Samuel , Pasto Arvid E. , Rourke William J.
Published: April 2005

The effect of surface oxygen concentration of silicon nitride powders on the properties of resulting ceramics was studied. A high‐purity silicon nitride powder was treated physically and chemically to modify its surface oxygen content. The resulting powders were hot‐pressed into dense ceramics using 6 wt% yttria as a sintering aid. Strength and oxidation resistance of these ceramics were measured and correlated with the powder and ceramic compositions as well as the resulting intergranular phases. Results show that the phases developed in yttria‐containing silicon nitride ceramics vary with slight changes in the initial powder oxygen content, as predicted, and that strength can be correlated to initial oxygen concentration. The mechanical strength vs oxygen content curve has a definite maximum; i.e., there is a small oxygen concentration range at which optimum ceramic strength is realized. Best results are obtained when the oxygen content is increased by thermal oxidation; other techniques such as chemical oxidation or addition of silica are not as effective, particularly in attaining high strength at elevated temperatures.
Control of the Interfacial Reactions in Nb‐Toughened MoSi2
Authors: Shaw Leon , Abbaschian Reza
Published: April 2005

Toughening of MoSi2 for high‐temperature applications can be achieved by incorporating ductile refractory‐metal reinforcements, provided that a coating is applied to prevent interdiffusion and reaction between the matrix and the reinforcements. In the present study, three different coating techniques for applying a thin Al2O3 film on Nb reinforcements as a diffusion barrier have been studied. The techniques consisted of (i) sol‐gel coating; (ii) physical vapor deposition (PVD); (iii) hot dipping in molten Al, followed by anodizing Al to form Al2O3. The processing parameters for the techniques were evaluated and the effectiveness of each coating as a diffusion barrier was assessed. For the present MoSi2 matrix which contains SiO2, PVD coatings provided the most effective diffusion barrier for processing MoSi2/Nb composites.
Influence of Loading Frequency on the Room‐Temperature Fatigue of a Carbon‐Fiber/SiC‐Matrix Composite
Authors: Shuler Stephen F. , Holmes John W. , Wu Xin , Roach David
Published: April 2005

The influence of cyclic loading frequency on the tensile fatigue life of a woven‐carbon‐fiber/SiC‐matrix composite was examined at room temperature. Tension‐tension fatigue experiments were conducted under load control, at sinusoidal frequencies of 1, 10, and 50 Hz. Using a stress ratio (σmin/σmax) of 0.1, specimens were subjected to maximum fatigue stresses of 310 to 405 MPa. There were two key findings: (1) the fatigue life and extent of modulus decay were influenced by loading frequency and (2) the postfatigue monotonic tensile strength increased after fatigue loading. For loading frequencies of 1 and 10 Hz, the fatigue limit (defined at 1 × 106 cycles) was approximately 335 MPa, which is over 80% of the initial monotonic strength of the composite; at 50 Hz, the fatigue limit was below 310 MPa. During 1‐ and 10‐Hz fatigue at a maximum stress of 335 MPa, the modulus exhibited an initially rapid decrease, followed by a partial recovery; at 50 Hz, and the same stress limits, the modulus continually decayed. The residual strength of the composite increased by approximately 20% after 1 × 106 fatigue cycles at 1 or 10 Hz under a peak stress of 335 MPa. The increase in strength is attributed in part to a decrease in the stress concentrations present near the crossover points of the 0° and 90° fiber bundles.
Sintering of Silicon Nitride with YAIO3 Additive
Authors: Kuzjukēvičs Anatolijs , Ishizaki Kozo
Published: April 2005

Sintering of Si3N4 powder with the addition of a Y2O3+ Al2O3 mixture or YAlO3 as sintering aids was investigated. Sintering was improved in the case of YAlO3 additive compared to that for the Y2O3+ Al2O3 mixture. An initial delay in densification was most likely caused by heterogeneity of the liquid phase formed in the case of the separate oxide additions at temperatures above 1700°C.
Modeling of Grain‐Size‐Dependent Microfracture‐Controlled Sliding Wear in Polycrystalline Alumina
Authors: Liu Haiyan , Fine Morris E.
Published: April 2005

To quantify grain‐size‐dependent sliding wear of polycrystalline alumina induced by grain‐boundary microfracture, an attempt is made to extend and combine Cho et al.'s fracture mechanics analysis and Fu and Evans' simple micro‐cracking theory. An analytical equation is derived to relate wear with microstructural parameters. Wear by intergranular microfracture occurs, provided that the combined stresses are greater than a threshold value. The critical sliding time to the wear transition decreases with increasing grain size, and the wear rate after the threshold is proportional to the grain size. The theoretical predictions are correlated with the lubricated sliding wear data of aluminas with different grain sizes reported by Cho et al.
Fatal Blastoschizomyces capitatus sepsis in a neutropenic patient with acute myeloid leukemia: first documented case from Greece
Authors: Christakis G. , Perlorentzou S. , Aslanidou M. , Megalakaki A. , Velegraki A.
Published: April 2005

Blastoschizomyces capitatus (formerly known as Geotrichum capitatum and Trichosporon capitatum) is a rare, yet an emerging, cause of invasive infections in immunosuppressed patients. Profound and prolonged neutropenia is the crucial predisposing factor for this yeast infection. Blastoschizomyces capitatus was isolated from peripheral blood cultures of a profoundly neutropenic patient with acute myeloid leukemia (M2 FAB). Despite administration of antifungal chemotherapy with liposomal amphotericin B at 4.5 mg kg−1 daily, the patient succumbed 4 days after initiation of treatment. Infections attributed to B. capitatus have generally a poor prognosis, although the yeast shows in vitro susceptibility to antifungal agents. Low flucytosine, caspofungin acetate, voriconazole and amphotericin B minimum inhibitory concentration values were also recorded with our isolate. The clinical relevance of the in vitro susceptibility testing against the isolate and the current antifungal chemotherapy regimens against B. capitatus systemic infections are discussed.
Temporal events in the intravenous challenge model for experimental Candida albicans infections in female mice
Authors: MacCallum Donna M. , Odds Frank C.
Published: April 2005

We characterized the intravenous (i.v.) challenge model for disseminated Candida albicans infection in female BALB/c and DBA/2 mice. Clearance of fungi from the bloodstream and appearance of fungi in tissues were measured at intervals after challenge with various doses of C. albicans. The wild‐type isolate SC5314 and derived strains CAF2–1 and CAI‐4 transformed with CIp10 were of equal virulence in the model. Variability in mouse survival times, kidney fungal burdens and cachexia was lowest when challenge inocula were within the range 104–105 CFU g−1 body weight in BALB/c mice, but brain fungal burdens and outcomes in DBA/2 mice were variable for all inocula tested. Critical times in the development of infections in optimally challenged BALB/c mice were at 5–10 h (bloodstream fully cleared of fungi), 24 h (start of exponential fungal growth in kidneys) and 48 h (50% of blood cultures become positive). Differential involvement of right and left kidneys occurred almost exclusively in mice challenged with <2 × 104 CFU g−1. We conclude that the i.v. challenge model in female BALB/c mice is now sufficiently well characterized to permit more refined experimentation in future virulence studies with C. albicans mutants.
Experimental dermatophytosis in calves caused by Trichophyton verrucosum culture
Authors: Obořilová E. , Rybnikář A.
Published: April 2005

Microconidia suspension of Trichophyton verrucosum virulent culture isolated originally from the mycotic lesions of cattle was inoculated epicutaneously to calves in various doses. Four application methods were selected, namely, onto the sheared and gently scarified skin, onto the sheared and non‐scarified skin, onto the non‐sheared and gently scarified skin, and onto the non‐sheared and non‐scarified skin. The inoculated area was 10 × 10 cm for all cases mentioned. When the application was performed onto the sheared and scarified skin, at least 18 000 microconidia of T. verrucosum per one animal had to be used to induce the mycotic disease in 100% of animals. This value was 10 times higher when the application was performed onto the non‐sheared and scarified skin, 100 times higher in the case of the sheared and non‐scarified skin and 1 000 times higher in the case of the non‐sheared and non‐scarified skin. The minimum infectious dose still capable of inducing dermatophytosis was 180 microconidia per 100 cm2 of the scarified skin, 18 000 microconidia per 100 cm2 of the sheared and non‐scarified skin, and 180 000 microconidia per 100 cm2 of the non‐sheared and non‐scarified skin.
Detection of Candida dubliniensis in oropharyngeal samples of Turkish HIV‐positive patients
Authors: Tekeli A. , Koyuncu E. , Dolapci I. , Guven G. S. , Sahin G. O. , Uzun O.
Published: April 2005

The incidence of Candida dubliniensis in immunocomprimised patients in Turkey has not yet been determined. In this study the presence of C. dubliniensis in oral rinse samples of human immunodeficiency virus (HIV)‐positive patients and healthy controls were investigated. Phenotypic tests like inability of growth at 45 °C, colony formation on Staib agar, intracellular β‐d‐glucosidase activity, carbohydrate assimilation profiles and polymerase chain reaction with species‐specific primers (DUBF and DUBR) were carried out for differentiation of C. dubliniensis. Of the 35 patients, four (11.4%) had C.dubliniensis in their oral cavity. Antifungal susceptibility testing of these C. dubliniensis isolates showed fluconazole MICs ranging from <0.06 to 32 μg ml−1 and amphotericin B from <0.06 to 0.25 μg ml−1. One isolate was dose‐dependently susceptible to fluconazole (32 μg ml−1). This study demonstrates C. dubliniensis in HIV‐positive patients from Turkey.
Nine male cases of tinea genitalis
Authors: Romano Clara , Ghilardi Alberto , Papini Manuela
Published: April 2005

Nine cases of tinea genitalis observed in Siena and Terni (Italy) between 1988 and 2003 are reported because of their infrequency. The patients were males ranging in age from 23 to 45 years. The lesions, situated on the penis, glans and scrotum, were preceded by dermatophytosis in other sites (groin five cases; feet two cases; toenails two cases; hands in one; beard in another). Mycological examination consisting of direct microscopy and culture led to isolation of Trichophyton rubrum in five cases, Epidermophyton floccosum in two and T. mentagrophytes var. interdigitalis in the others. Clinical diagnosis is not always easy. In three cases the lesions had been misdiagnosed as eczema.
Detection of Candida dubliniensis in oropharyngeal samples from human immunodeficiency virus infected and non‐infected patients and in a yeast culture collection
Authors: Faggi E. , Pini G. , Campisi E. , Martinelli C. , Difonzo E.
Published: April 2005

The incidence of Candida dubliniensis in oropharyngeal swabs of 132 human immunodeficiency virus (HIV)‐positive and 89 HIV‐negative patients was determined. The samples were plated onto CHROMagar Candida medium and 82 strains, presumptively identified as C. albicans or C. dubliniensis, were further investigated (temperature test, chlamydoconidia production, specific primer PCR). In addition, 487 collection strains (isolated from clinical samples and previously identified as C. albicans on the basis of a positive germ tube test) were screened in order to identify C. dubliniensis isolates. Two C. dubliniensis strains were isolated from two HIV‐positive patients without oral candidiasis. Candida dubliniensis was not isolated from 89 HIV‐negative patients nor was it identified among the collection strains.
Papular eruption on a tattoo: A case of primary inoculation tuberculosis
Authors: Wong Hoong‐Wai , Tay Yong‐Kwang , Sim Chee‐Seng
Published: April 2005

The pathogenesis of inoculation cutaneous tuberculosis requires a break in the skin, through minor abrasions or injury, allowing the entry of tubercle bacilli. We report a 33‐year‐old man who presented with erythematous papules over a tattoo on the right upper arm, 1 month after undergoing a tattoo procedure. Histology and cultures revealed infection with Mycobacterium tuberculosis. He was started on a 9‐month course of antituberculous medication and 3 months after initiation of the drugs all the papules had subsided. He has since completed the course of therapy and there has been no recurrence 1 year after treatment was started.
Grzybowski's generalized eruptive keratoacanthoma: Remission with cyclophosphamide
Authors: Oakley Amanda , Ng Stephen
Published: April 2005

A 57‐year‐old woman presented with intensely pruritic generalized eruptive keratoacanthomas affecting cutaneous and mucosal surfaces (Grzybowski syndrome). She derived marginal benefit from anti‐pruritic agents, acitretin and methotrexate. However, cyclophosphamide 100 mg daily for 1 month followed by 3 months at 200 mg daily resulted in remarkable improvement and eventual remission without further treatment. The disease resulted in severe ectropion of upper and lower eyelids bilaterally. Two years after the onset of her disease, the lower lid ectropions were repaired using skin grafting. There was no evidence for papillomavirus infection.
Polynomial Trend Regression With Long‐memory Errors
Authors: Ho Hwai‐Chung , Hsu Nan‐Jung
Published: April 2005

Abstract.  For a time series generated by polynomial trend with stationary long‐memory errors, the ordinary least squares estimator (OLSE) of the trend coefficients is asymptotically normal, provided the error process is linear. The asymptotic distribution may no longer be normal, if the error is in the form of a long‐memory linear process passing through certain nonlinear transformations. However, one hardly has sufficient information about the transformation to determine which type of limiting distribution the OLSE converges to and to apply the correct distribution so as to construct valid confidence intervals for the coefficients based on the OLSE. The present paper proposes a modified least squares estimator to bypass this drawback. It is shown that the asymptotic normality can be assured for the modified estimator with mild trade‐off of efficiency even when the error is nonlinear and the original limit for the OLSE is non‐normal. The estimator performs fairly well when applied to various simulated series and two temperature data sets concerning global warming.
Making profits in wartime: corporate profits, inequality, and GDP in Germany during the First World War1
Authors: BATEN JOERG , SCHULZ RAINER
Published: April 2005

Making profits in wartime: corporate profits, inequality, and GDP in Germany during the First World War. This article reconsiders, and rejects, Kocka's (1973) hypothesis that a strong income redistribution from workers to capital owners occurred in Germany during the First World War. A small number of firms profited from the war, but the majority experienced a decline in real income, similar to the decline in workers' real wages. This finding also has important implications for the political history of the Weimar Republic. The authors also use their figures to improve German GDP estimates for the war period, since their sample makes it possible to estimate private service sector development. Economic indicators were worse for the war year of 1917 than previously believed.
Response surface modelling for cleaning and disinfecting materials used in milking systems with electrolysed oxidizing water
Authors: WALKER STEPHEN P , DEMIRCI ALI , GRAVES ROBERT E , SPENCER STEPHEN B , ROBERTS ROBERT F
Published: April 2005

Electrolysed oxidizing (EO) water is produced by passing a DC current through a weak sodium chloride solution, resulting in alkaline and acidic EO water. The goal of this research was to determine whether EO water could be used as an acceptable cleaning and disinfecting agent for materials used in pipeline milking systems. Small pieces of materials commonly used in milking systems were soiled using raw milk inoculated with a cocktail of four bacterial cultures similar to those commonly found in raw milk, and then cleaned by soaking in alkaline EO water followed by soaking in acidic EO water at various treatment times and temperatures. Effective treatment time and temperature combinations were determined by response surface design for a temperature range of 25–60°C and a time range of 5–20 min. Treated materials were evaluated by aerobic plate counts and ATP bioluminescence to assess the disinfecting and cleaning effectiveness of EO water. Most of the treatments at 60°C and several treatments at lower temperatures successfully removed all detectable bacteria and ATP. Overall, the results of this study indicated that EO water has the potential to be used as a cleaning and disinfecting agent for materials used in milking systems.
Evaluation of the ability of Yarrowia lipolytica to impart strain‐dependent characteristics to cheese when used as a ripening adjunct
Authors: LANCIOTTI ROSALBA , VANNINI LUCIA , LOPEZ CLEMENCIA CHAVES , GOBBETTI MARCO , GUERZONI M ELISABETTA
Published: April 2005

Four Yarrowia lipolytica strains were tested as cheese‐ripening adjuncts with milk culture in cheese production to evaluate their effects on the microbiological and biochemical features of the cheeses. The Y. lipolytica strains were able to overcome the other naturally occurring yeasts and were compatible with lactic acid bacteria (LAB). Fourier transform infrared (FTIR) profiles and analysis of free fatty acids (FFAs) released during ripening showed that the strains induced a marked lipolysis and gave rise to different FFAs accumulation over time with respect to the control. Strain‐dependent protein breakdown patterns were identified and these biochemical differences resulted in different cheese organoleptic characteristics.
Direct evidence for the involvement of brain‐derived neurotrophic factor in the development of a neuropathic pain‐like state in mice
Authors: Yajima Yoshinori , Narita Minoru , Usui Aiko , Kaneko Chihiro , Miyatake Mayumi , Narita Michiko , Yamaguchi Takanori , Tamaki Hiroko , Wachi Hiroshi , Seyama Yoshiyuki , Suzuki Tsutomu
Published: April 2005

Thermal hyperalgesia and tactile allodynia induced by sciatic nerve ligation were completely suppressed by repeated intrathecal (i.t.) injection of a TrkB/Fc chimera protein, which sequesters endogenous brain‐derived neurotrophic factor (BDNF). In addition, BDNF heterozygous (+/–) knockout mice exhibited a significant suppression of nerve ligation‐induced thermal hyperalgesia and tactile allodynia compared with wild‐type mice. After nerve ligation, BDNF‐like immunoreactivity on the superficial laminae of the ipsilateral side of the spinal dorsal horn was clearly increased compared with that of the contralateral side. It should be noted that a single i.t. injection of BDNF produced a long‐lasting thermal hyperalgesia and tactile allodynia in normal mice, and these responses were abolished by i.t. pre‐treatment with either a Trk‐dependent tyrosine kinase inhibitor K‐252a or a selective protein kinase C (PKC) inhibitor Ro‐32‐0432. Supporting these findings, we demonstrated here for the first time that the increase in intracellular Ca2+ concentration by application of BDNF in cultured mouse spinal neurons was abolished by pre‐treatment with either K‐252a or Ro‐32‐0432. Taken together, these findings suggest that the binding of spinally released BDNF to TrkB by nerve ligation may activate PKC within the spinal cord, resulting in the development of a neuropathic pain‐like state in mice.
Up‐regulation of interleukin‐6 induced by prostaglandin E2 from invading macrophages following nerve injury: an in vivo and in vitro study
Authors: Ma Weiya , Quirion Remi
Published: April 2005

The mechanisms underlying neuropathic pain caused by nerve injury are not well understood. Inflammatory responses in injured nerves are likely to be key contributing factors in the generation and maintenance of neuropathic pain. The pro‐inflammatory cytokine interleukin‐6 (IL‐6) is up‐regulated in invading macrophages and has been implicated in the development of neuropathic pain. We previously demonstrated that invading macrophages up‐regulate cyclooxygenase 2 (COX2) and prostaglandin E2 (PGE2) receptors EP1 and EP4, suggesting that PGE2 may affect macrophage function via autocrine or paracrine mechanisms. This study was undertaken to determine whether PGE2 is involved in the up‐regulation of IL‐6 in invading macrophages. Two weeks following partial sciatic nerve ligation, numerous IL‐6 immunoreactive (IR) cell profiles were present in injured nerves. Colocalization of IL‐6 with the invading macrophage marker ED1 or with COX2 was frequently observed. IL‐6‐IR, COX2‐IR and ED1‐IR cells were present only in cultures derived from injured nerve segments. PGE2 and IL‐6 release from cultured cells derived from injured nerves was increased significantly compared with uninjured nerves. Non‐selective and selective COX2 inhibitors suppressed PGE2 and IL‐6 release. Treatment with PGE2 further enhanced IL‐6 release in a concentration‐ and time‐dependent manner. A selective EP4 receptor antagonist L‐161982 was able to suppress IL‐6 release, whereas an EP1 receptor antagonist, SC19220, was ineffective. Moreover, a protein kinase C inhibitor, calphostin C, dramatically suppressed IL‐6 release, whereas a protein kinase A inhibitor H‐89 and a Ca2+ chelator EGTA failed. Taken together, our data suggest that PGE2 is involved in mediating the up‐regulation of IL‐6 occurring in invading macrophages. This action is mediated through an EP4 receptor and the protein kinase C signaling pathway.
Regulation of cholesterol/lipid biosynthetic genes by Egr2/Krox20 during peripheral nerve myelination
Authors: LeBlanc Scott E. , Srinivasan Rajini , Ferri Cinzia , Mager Gennifer M. , Gillian‐Daniel Anne Lynn , Wrabetz Lawrence , Svaren John
Published: April 2005

Myelination of peripheral nerves by Schwann cells requires a large amount of lipid and cholesterol biosynthesis. To understand the transcriptional coordination of the myelination process, we have investigated the developmental relationship between early growth response 2 (Egr2)/Krox20 – a pivotal regulator of peripheral nerve myelination – and the sterol regulatory element binding protein (SREBP) pathway, which controls expression of cholesterol/lipid biosynthetic genes. During myelination of sciatic nerve, there is a very significant induction of SREBP1 and SREBP2, as well as their target genes, suggesting that the SREBP transactivators are important regulators in the myelination process. Egr2/Krox20 does not appear to directly regulate the levels of SREBP pathway components, but rather, we found that Egr2/Krox20 and SREBP transactivators can synergistically activate promoters of several SREBP target genes, indicating that direct induction of cholesterol/lipid biosynthetic genes by Egr2/Krox20 is a part of the myelination program regulated by this transactivator.
Constitutive expression and localization of cytochrome P‐450 1A1 in rat and human brain: presence of a splice variant form in human brain1
Authors: Chinta Shankar J. , Kommaddi Reddy P. , Turman Cheri M. , Strobel Henry W. , Ravindranath Vijayalakshmi
Published: April 2005

Cytochrome P‐450 function as mono‐oxygenases and metabolize xenobiotics. CYP1A1, a cytochrome P‐450 enzyme, bioactivates polycyclic aromatic hydrocarbons to reactive metabolite(s) that bind to DNA and initiate carcinogenesis. Northern and immunoblot analyses revealed constitutive expression of Cyp1a1 and CYP1A1 in rat and human brain, respectively. CYP1A1 mRNA and protein were localized predominantly in neurons of cerebral cortex, Purkinje and granule cell layers of cerebellum and pyramidal neurons of CA1, CA2, and CA3 subfields of the hippocampus. RT–PCR analyses using RNA obtained from autopsy human brain samples demonstrated the presence of a splice variant having a deletion of 87 bp of exon 6. This splice variant was present in human brain, but not in the liver from the same individual, and was absent in rat brain and liver. Structural modeling indicated broadening of the substrate access channel in the brain variant. The study demonstrates the presence of a unique cytochrome P‐450 enzyme in human brain that is generated by alternate splicing. The presence of distinct cytochrome P‐450 enzymes in human brain that are different from well‐characterized hepatic forms indicates that metabolism of xenobiotics including drugs could occur in brain by pathways different from those known to occur in liver.
Poly C binding protein, a single‐stranded DNA binding protein, regulates mouse µ‐opioid receptor gene expression
Authors: Ko Jane L. , Loh Horace H.
Published: April 2005

Previously, a single‐stranded (ss) DNA element, polypyrimidine (PPy) element, was found to be important for the proximal promoter activity of mouse µ‐opioid receptor (MOR) gene in a neuronal cell model. In this study, we identified the presence of unknown ssDNA binding proteins specifically bound to MOR ssPPy element in the mouse brain, implicating the physiological significance of these proteins. To identify the ssDNA binding proteins, yeast one‐hybrid system with PPy element as the bait was used to screen a mouse brain cDNA library. The clone encoding poly C binding protein (PCBP) was obtained. Its full‐length cDNA sequence and protein with molecular weight approximately 38 kDa were confirmed. Electrophoretic mobility shift analysis (EMSA) revealed that PCBP bound to ssPPy element, but not doubled‐stranded, in a sequence‐specific manner. EMSA with anti‐PCBP antibody demonstrated the involvement of PCBP in MOR ssPPy/proteins complexes of mouse brain and MOR expressing neuroblastoma NMB cells. Functional analysis showed that PCBP trans‐activated MOR promoter as well as a heterologous promoter containing MOR PPy element. Importantly, ectopic expression of PCBP in NMB cells up‐regulated the expression level of endogenous MOR gene in vivo in a dose‐dependent manner. Collectively, above results suggest that PCBP participates in neuronal MOR gene expression.
Activation of Rac1 by phosphatidylinositol 3‐kinase in vivo: role in activation of mitogen‐activated protein kinase (MAPK) pathways and retinoic acid‐induced neuronal differentiation of SH‐SY5Y cells
Authors: Pan Jing , Kao Yu‐Lin , Joshi Suchitra , Jeetendran Seena , DiPette Donald , Singh Ugra S.
Published: April 2005

Rho GTPases such as RhoA, Rac1 and Cdc42 are crucial players in the regulation of signal transduction pathways required for neuronal differentiation. Using an in vitro cell culture model of neuroblastoma SH‐SY5Y cells, we demonstrated previously that RhoA is an in vivo substrate of tissue transglutaminase (TGase) and retinoic acid (RA) promoted activation of RhoA by transamidation. Although activation of RhoA promoted cytoskeletal rearrangement in SH‐SY5Y cells, it was not involved in induction of neurite outgrowth. Here, we demonstrate that RA promotes activation of Rac1 in SH‐SY5Y cells in a transamidation‐independent manner. RA‐induced activation of Rac1 is mediated by phosphatidylinositol 3‐kinase (PI3K), probably because of phosphorylation of the p85 regulatory subunit by Src kinases. Over‐expression of constitutively active PI3K or Rac1‐V12 induces neurite outgrowth, activation of mitogen activated protein kinases (MAPKs), and expression of neuronal markers. The PI3K inhibitor LY294002, or over‐expression of dominant negative Rac1‐N17, blocks RA‐induced neurite outgrowth, activation of MAPKs, and expression of neuronal markers, suggesting that activation of PI3K/Rac1 signaling represents a potential mechanism for regulation of neuronal differentiation in SH‐SY5Y cells.
EFFECT OF PRICE ON PLEASANTNESS RATINGS AND USE INTENTIONS FOR A CHOCOLATE BAR IN THE PRESENCE AND ABSENCE OF A HEALTH CLAIM
Authors: DI MONACO R. , OLLILA S. , TUORILA H.
Published: April 2005

The effect of price information on hedonic and use intention responses to a chocolate bar was investigated in the absence and presence of a health claim related to energy, satiety value and cholesterol content. First, Finnish students (n = 79) tasted and rated blind three chocolate bars (one regular, two containing functional ingredients). Second, one group (“Informed,” n = 40) evaluated the samples with the health claim and price information, the other group (“Control,” n = 39) as a regular bar with price information only. A separate focus group (n = 6) interview was conducted to obtain further views of the claim and samples. Neither the health claim nor the price affected pleasantness ratings, while the increasing price significantly reduced the likelihood of buying and preferred frequency of eating the chocolate bar in both groups. Price affected the likelihood of buying more strongly among females than among males, and involvement with chocolate bars affected the likelihood of buying in the control, but not in the informed group. The focus group interview indicated that healthfulness might be irrelevant for chocolate products. Overall, price heavily affected the likelihood of buying the target product, but price and the health claim were incapable of altering hedonic responses to it.
The plasma crystal
Authors: Thoma M. H. , Kretschmer M. , Rothermel H. , Thomas H. M. , Morfill G. E.
Published: April 2005

A complex plasma is a multi-component low-temperature plasma containing microparticles, for example, dust, in addition to ions, electrons, and neutral gas atoms. Under certain conditions these microparticles can form a regular structure, a plasma crystal. This new form of matter provides a unique possibility for studying phase transitions and dynamical aspects of many-body systems at the microscopic level. Complex plasmas play an important role in astrophysics as well as in technology. We describe an undergraduate experiment in which students can produce and investigate the plasma crystal and the transition to the liquid phase.
Impact of peer interaction on conceptual test performance
Authors: Singh Chandralekha
Published: April 2005

We analyze the effectiveness of working in pairs on the Conceptual Survey of Electricity and Magnetism test in a calculus-based introductory physics course. Students who collaborated with a peer showed significantly larger normalized gain on individual testing than those who did not collaborate. We did not find statistically significant differences between the performance of students who were given an opportunity to formulate their own response before the peer discussions, compared to those who were not. Peer collaboration also shows evidence for the co-construction of knowledge. Discussions with individual students show that students themselves value peer interaction. We discuss the effect of pairing students with different individual achievements.
POLARIZATION CORRELATIONS IN PAIR PRODUCTION FROM CHARGED AND NEUTRAL STRINGS
Authors: MANOUKIAN E. B. , YONGRAM N.
Published: April 2005

Polarization correlations of e+e- pair productions from charged and neutral Nambu strings are investigated, via photon and graviton emissions, respectively and explicit expressions for their corresponding probabilities are derived and found to be speed dependent. The strings are taken to be circularly oscillating closed strings, as perhaps the simplest solution of the Nambu action. In the extreme relativistic case, these probabilities coincide, but, in general, are different, and such inquiries, in principle, indicate whether the string is charged or uncharged. It is remarkable that these dynamical relativistic quantum field theory calculations lead to a clear violation of Local Hidden Variables theories.
ANALYSIS OF SWEDISH FISHERY COMPANY USING SIV® MODEL: A CASE STUDY
Authors: ABOUZEEDAN ADLI , BUSLER MICHAEL
Published: April 2005

In his original work of the Survival Index Value (SIV®) model, Dr. Adli Abouzeedan proposed a new parameter, which he named as the Survival Index (SI) (see Abouzeedan, 2001; Abouzeedan and Busler, 2002a). The new parameter is used to evaluate the performance of Small and Medium-size Enterprises (SMEs) utilizing firm survivability as an indicator. The SI is calculated using an equation known as Survival Index (SI) Value Equation or SIE. In this paper, we applied the SIV® model to run an analysis on a very young Swedish firm and up to our knowledge, for the first time. The firm is a small one, working within a business sector defined as "fish preparation industry". This particular enterprise had a bad performance through its short life. The purpose of this study is to truly determine if the SIV® model has the capacity to indicate the performance of the firm. The case study presented in this work showed the valuable analytical power of the new model since it succeeded in giving a clear indication of the worsening situation of the enterprise. During the SIV® analysis of this Swedish firm new concepts have been introduced which do increase the practicality and analytical capacity of the model.
A FRAMEWORK FOR CONJECTURING ENTREPRENEURIAL OPPORTUNITIES: AN APPLICATION TO INDIVIDUALIZATION OF DEMAND IN THE UNDERTAKING BUSINESS
Authors: VAN GELDEREN MARCO
Published: April 2005

In the last few decades, the manner in which western society deals with death has changed under the influence of individualization processes. In this paper, directions of emerging opportunities for new products or services are pointed out that respond to this development. For this purpose, five types of heuristic information are provided and analyzed. First, background information about the market. Second, an analysis of consumer wants, problems, and behavior. Third, an analysis of the change factor that explains how wants of consumer are becoming different. Fourth, a description of innovations that already try to meet these changed wants. Fifth, conceptualizations of the market that define the market in a reframed manner. The paper concludes that the centrality of the self (and its cessation by death), the importance of expression of one's authentic personality, the diminished authority of traditional frameworks that explain death, and a want for self-esteem in response to mortality salience all give rise to opportunities for new products and services in response to individualizing manners of dealing with death.
A PARALLEL GENETIC ALGORITHM FOR THE GEOMETRICALLY CONSTRAINED SITE LAYOUT PROBLEM WITH UNEQUAL-SIZE FACILITIES
Authors: HARMANANI HAIDAR M. , ZOUEIN PIERRETTE P. , HAJAR AOUNI M.
Published: April 2005

Parallel genetic algorithms techniques have been used in a variety of computer engineering and science areas. This paper presents a parallel genetic algorithm to solve the site layout problem with unequal-size and constrained facilities. The problem involves coordinating the use of limited space to accommodate temporary facilities subject to geometric constraints. The problem is characterised by affinity weights used to model transportation costs between facilities, and by geometric constraints between relative positions of facilities on site. The algorithm is parallelised based on a message passing SPMD architecture using parallel search and chromosomes migration. The algorithm is tested on a variety of layout problems to illustrate its performance. In specific, in the case of: (1) loosely versus tightly constrained layouts with equal levels of interaction between facilities, (2) loosely versus tightly packed layouts with variable levels of interactions between facilities, and (3) loosely versus tightly constrained layouts. Favorable results are reported.
Kidney expression of glutathione peroxidase-1 is not protective against streptozotocin-induced diabetic nephropathy
Authors: de Haan Judy B. , Stefanovic Nada , Nikolic-Paterson David , Scurr Lyndee L. , Croft Kevin D. , Mori Trevor A. , Hertzog Paul , Kola Ismail , Atkins Robert C. , Tesch Gregory H.
Published: April 2005

In many diseases, including progressive renal disorders, tissue injury and pathological intracellular signaling events are dependent on oxidative stress. Glutathione peroxidase-1 (Gpx1) is an antioxidant enzyme that is highly expressed in the kidney and removes peroxides and peroxynitrite that can cause renal damage. Therefore, we examined whether this abundant renal antioxidant enzyme limits renal damage during the development of type 1 diabetic nephropathy. Wild-type (Gpx1+/+) and deficient (Gpx1−/−) mice were made diabetic by intraperitoneal injection of streptozotocin (100 mg/kg) on 2 consecutive days. Diabetic Gpx1+/+ and −/− mice with equivalent blood glucose levels (23 ± 4 mM) were selected and examined after 4 mo of diabetes. Compared with normal mice, diabetic Gpx1+/+ and −/− mice had a two- to threefold increase in urine albumin excretion at 2 and 4 mo of diabetes. At 4 mo, diabetic Gpx1+/+ and −/− mice had equivalent levels of oxidative renal injury (increased kidney reactive oxygen species, kidney lipid peroxidation, urine isoprostanes, kidney deposition of advanced glycoxidation, and nitrosylation end products) and a similar degree of glomerular damage (hypertrophy, hypercellularity, sclerosis), tubular injury (apoptosis and vimentin expression), and renal fibrosis (myofibroblasts, collagen, TGF-β excretion). A lack of Gpx1 was not compensated for by increased levels of catalase or other Gpx isoforms in diabetic kidneys. Contrary to expectations, this study showed that the high level of Gpx1 expressed in the kidney is not protective against the development of renal oxidative stress and nephropathy in a model of type 1 diabetes.
Spatial pattern of ventilation-perfusion mismatch following acute pulmonary thromboembolism in pigs
Authors: Tsang John Y. C. , Lamm Wayne J. E. , Starr Ian R. , Hlastala Michael P.
Published: April 2005

We studied the spatial distribution of the abnormal ventilation-perfusion (V̇a/Q̇) units in a porcine model of acute pulmonary thromboembolism (APTE), using the fluorescent microsphere (FMS) technique. Four piglets (∼22 kg) were anesthetized and ventilated with room air in the prone position. Each received ∼20 g of preformed blood clots at time t = 0 min via a large-bore central venous catheter, until the mean pulmonary arterial pressure reached 2.5 times baseline. The distributions of regional V̇a and blood flow (Q̇) at five time points ( t = −30, −5, 30, 60, 120 min) were mapped by FMS of 10 distinct colors, i.e., aerosolization of 1-μm FMS for labeling V̇a and intravenous injection of 15-μm FMS for labeling Q̇. Our results showed that, at t = 30 min following APTE, mean V̇a/Q̇ (V̇a/Q̇ = 2.48 ± 1.12) and V̇a/Q̇ heterogeneity (log SD V̇a/Q̇ = 1.76 ± 0.23) were significantly increased. There were also significant increases in physiological dead space (11.2 ± 12.7% at 60 min), but the shunt fraction (V̇a/Q̇ = 0) remained minimal. Cluster analyses showed that the low V̇a/Q̇ units were mainly seen in the least embolized regions, whereas the high V̇a/Q̇ units and dead space were found in the peripheral subpleural regions distal to the clots. At 60 and 120 min, there were modest recoveries in the hemodynamics and gas exchange toward baseline. Redistribution pattern was mostly seen in regional Q̇, whereas V̇a remained relatively unchanged. We concluded that the hypoxemia seen after APTE could be explained by the mechanical diversion of Q̇ to the less embolized regions because of the vascular obstruction by clots elsewhere. These low V̇a/Q̇ units created by high flow, rather than low V̇a, accounted for most of the resultant hypoxemia.
The role of neovascularisation in the resolution of venous thrombus
Authors: Modarai Bijan , Guiver Burnand Kevin , Humphries Julia , Waltham Matthew , Smith Alberto
Published: April 2005

Deep vein thrombosis (DVT) can give rise to chronic debilitating complications, which are expensive to treat. Anticoagulation, the standard therapy for DVT, prevents propagation, but does not remove the existing thrombus, which undergoes slow natural resolution. Alternative forms of treatment that accelerate resolution may arise from a better understanding of the cellular and molecular pathways that regulate the natural resolution of thrombi. This review will outline our current understanding of the mechanisms of thrombus resolution and the role of neovascularisation in this process. Novel experimental treatments that may one day find clinical use are also discussed. The process of thrombus resolution resembles wound healing. The mainly monocytic inflammatory infiltrate, which develops, is associated with the appearance of vascular channels. These cells may drive resolution by encouraging angiogenesis, which contributes to restoration of the vein lumen. Significant numbers of bone marrow-derived progenitor cells have also been found in naturally resolving thrombi, but their precise phenotype and their role in thrombus recanalisation is unclear. Enhanced thrombus neovascularisation and rapid vein recanalisation have been achieved in experimental models with proangiogenic agents. Recent reports of the role of bone marrow-derived progenitor cells in the revascularisation of ischaemic tissues suggest that it may be possible to obtain the same effect by delivering pluripotent or lineage specific stem cells into thrombus. These cells could contribute to thrombus recanalisation by expressing a variety of proangiogenic cytokines or by lining the new vessels that appear within the thrombus.
Phospholipid vesicles interfere with the binding of antibody fragments to the light chain of factor VIII
Authors: Lewis Deborah , Bovenschen Niels , Mertens Koen , Voorberg Jan , Ortel Thomas
Published: April 2005

Factor VIII binds to phospholipid membranes through the C2 domain (S2173-Y2332). Residues M2199, F2200, L2251, L2252, V2223, W2313 and V2314 at the tips of β-hairpins and loops are thought to contribute to phospholipid membrane binding. Similarly, residues in the C2 domain of the homologous protein factor V form a phospholipid binding site, but residues in the A3 and C1 domains are also thought to contribute to membrane binding. Phage display technology was previously used to isolate factor VIII light chain specific single-chain variable domain fragments (scFv) from patients with factor VIII inhibitors. Phospholipid vesicles inhibited the binding of factor VIII to scFvsWR1 and WR16 (epitope: E2181-M2199) with half saturation values of 23 and 47 μM respectively. The single point mutant F2200A factor VIII light chain bound to WR1 and WR16 with a much lower affinity than wild type protein suggesting that residue F2200 is also included in the epitopes of these scFvs. Binding of factor VIII to C2-specific scFvsWR13 and EL14 (epitope: K2207-M2321) was not inhibited by phospholipid vesicles. Consistent with this, F2200A factor VIII light chain bound to these scFvs with the same affinity as the wild type protein. However, phospholipid vesicles also inhibited the binding of factor VIII to the A3-C1-specific scFvs KM36 (epitope: Q1778-D1840) and KM38 (epitope: S1690-N1777 and/or V1841-N2172) with half saturation values of 84 and 165 μM, respectively, suggesting that the A3 and/or C1 domains may contribute to membrane binding of the cofactor.