bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Immunodeficiency Virus Type 1 N-Terminal Capsid Mutants Containing Cores with Abnormally High Levels of Capsid Protein and Virtually No Reverse Transcriptase
Authors: Tang Shixing , Murakami Tsutomu , Cheng Naiqian , Steven Alasdair C. , Freed Eric O. , Levin Judith G.
Published: November 2003

We previously described the phenotype associated with three alanine substitution mutations in conserved residues (Trp23, Phe40, and Asp51) in the N-terminal domain of human immunodeficiency virus type 1 capsid protein (CA). All of the mutants produce noninfectious virions that lack conical cores and, despite having a functional reverse transcriptase (RT), are unable to initiate reverse transcription in vivo. Here, we have focused on elucidating the mechanism by which these CA mutations disrupt virus infectivity. We also report that cyclophilin A packaging is severely reduced in W23A and F40A virions, even though these residues are distant from the cyclophilin A binding loop. To correlate loss of infectivity with a possible defect in an early event preceding reverse transcription, we modeled disassembly by generating viral cores from particles treated with mild nonionic detergent; cores were isolated by sedimentation in sucrose density gradients. In general, fractions containing mutant cores exhibited a normal protein profile. However, there were two striking differences from the wild-type pattern: mutant core fractions displayed a marked deficiency in RT protein and enzymatic activity (<5% of total RT in gradient fractions) and a substantial increase in the retention of CA. The high level of core-associated CA suggests that mutant cores may be unable to undergo proper disassembly. Thus, taken together with the almost complete absence of RT in mutant cores, these findings can account for the failure of the three CA mutants to synthesize viral DNA following virus entry into cells.
Human Immunodeficiency Virus Type 1 Infection Inhibits Granulocyte-Macrophage Colony-Stimulating Factor-Induced Activation of STAT5A in Human Monocyte-Derived Macrophages
Authors: Warby Tammra J. , Crowe Suzanne M. , Jaworowski Anthony
Published: November 2003

Human immunodeficiency virus type 1 (HIV-1) infects cells of the monocyte/macrophage lineage. While infection of macrophages by HIV-1 is generally not cytopathic, it does impair macrophage function. In this study, we examined the effect of HIV-1 infection on intracellular signaling in human monocyte-derived macrophages (MDM) stimulated with the growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF is an important growth factor for cells of both the macrophage and granulocyte lineages and enhances effector functions of these cells via the heterodimeric GM-CSF receptor (GM-CSFR). A major pathway which mediates the effects of GM-CSF on macrophages involves activation of the latent transcription factor STAT5A via a Janus kinase 2 (JAK2)-dependent pathway. We demonstrate that GM-CSF-induced activation of STAT5A is inhibited in MDM after infection in vitro with the laboratory-adapted R5 strain of HIV-1, HIV-1Ba-L, but not after infection with adenovirus. HIV-1 infection of MDM did not decrease the STAT5A or JAK2 mRNA level or STAT5A protein level or result in increased constitutive activation of STAT5A. Surface expression of either the α-chain or common βc-chain of GM-CSFR was also unaffected. We conclude that HIV-1 inhibits GM-CSF activation of STAT5A without affecting expression of the known components of the signaling pathway. These data provide further evidence of disruption of cellular signaling pathways after HIV-1 infection, which may contribute to immune dysfunction and HIV-1 pathogenesis.
Functional Interaction between the Herpes Simplex Virus Type 1 Polymerase Processivity Factor and Origin-Binding Proteins: Enhancement of UL9 Helicase Activity
Authors: Trego Kelly S. , Parris Deborah S.
Published: November 2003

The origin (ori)-binding protein of herpes simplex virus type 1 (HSV-1), encoded by the UL9 open reading frame, has been shown to physically interact with a number of cellular and viral proteins, including three HSV-1 proteins (ICP8, UL42, and UL8) essential for ori-dependent DNA replication. In this report, it is demonstrated for the first time that the DNA polymerase processivity factor, UL42 protein, provides accessory function to the UL9 protein by enhancing the 3′-to-5′ helicase activity of UL9 on partially duplex nonspecific DNA substrates. UL42 fails to enhance the unwinding activity of a noncognate helicase, suggesting that enhancement of unwinding requires the physical interaction between UL42 and UL9. UL42 increases the steady-state rate for unwinding a 23/38-mer by UL9, but only at limiting UL9 concentrations, consistent with a role in increasing the affinity of UL9 for DNA. Optimum enhancement of unwinding was observed at UL42/UL9 molecular ratios of 4:1, although enhancement was reduced when high UL42/DNA ratios were present. Under the assay conditions employed, UL42 did not alter the rate constant for dissociation of UL9 from the DNA substrate. UL42 also did not significantly reduce the lag period which was observed following the addition of UL9 to DNA, regardless of whether UL42 was added to DNA prior to or at the same time as UL9. Moreover, addition of UL42 to ongoing unwinding reactions increased the steady-state rate for unwinding, but only after a 10- to 15-min lag period. Thus, the increased affinity of UL9 for DNA most likely is the result of an increase in the rate constant for binding of UL9 to DNA, and it explains why helicase enhancement is observed only at subsaturating concentrations of UL9 with respect to DNA. In contrast, ICP8 enhances unwinding at both saturating and subsaturating UL9 concentrations and reduces or eliminates the lag period. The different means by which ICP8 and UL42 enhance the ability of UL9 to unwind DNA suggest that these two members of the presumed functional replisome may act synergistically on UL9 to effect initiation of HSV-1 DNA replication in vivo.
Convergence of RNA
cis
Elements and Cellular Polyadenylation Factors in the Regulation of Human Cytomegalovirus UL37 Exon 1 Unspliced RNA Production
Authors: Su Yan , Adair Richard , Davis Candice N. , DiFronzo Nancy L. , Colberg-Poley Anamaris M.
Published: November 2003

The human cytomegalovirus (HCMV) UL36-38 immediate early (IE) locus encodes proteins required for its growth. The UL37 promoter drives production of an unspliced and several alternatively spliced RNAs. The UL37 exon 1 (UL37x1) unspliced RNA is abundant from IE to late times of HCMV infection, whereas the UL37 spliced RNAs are markedly less abundant. Production of the UL37x1 unspliced RNA requires polyadenylation (PA) at nucleotide 50998, which lies within intron 1, upstream of the UL37 exon 2 (UL37x2) acceptor. The physical proximity of its
cis
elements suggests steric hindrance between PA and splicing machineries for UL37 pre-mRNA. To test this possibility, we generated site-specific mutants in Target 1 PA and RNA splicing
cis
elements and compared the PA and splicing efficiencies of mutant RNAs with those of wild-type RNA. The mutually exclusive processing events of UL37x1 PA and UL37x1-UL37x2 splicing have been accurately recapitulated in transfected permissive human fibroblasts (HFFs) expressing a Target 1 minigene RNA, which contains the required splicing and PA
cis
elements. Two mutants in the invariant PA signal dramatically decreased UL37x1 PA as expected and, concomitantly, increased the efficiency of UL37x1-UL37x2 RNA splicing. Consistent with these results, changes to consensus UL37x1 donor and UL37x2 acceptor sites increased the efficiency of UL37x1-UL37x2 RNA splicing but decreased the efficiency of UL37x1 PA. Moreover, HCMV infection of HFFs increased the abundance of the PA cleavage stimulatory factor CstF-64, the potent splicing suppressor PTB, and the hypophosphorylated form of the splicing factor SF2 at 4 h postinfection. Induction of these factors further favors production of the UL37x1 unspliced RNA over that of the spliced RNAs. Taken together, these results suggest that there is a convergence in UL37 RNA regulation by
cis
elements and cellular proteins which favors production of the UL37x1 unspliced RNA during HCMV infection at the posttranscriptional level.
Replication-Defective Adenoviral Vaccine Vector for the Induction of Immune Responses to Dengue Virus Type 2
Authors: Jaiswal Smita , Khanna Navin , Swaminathan S.
Published: November 2003

A recombinant replication-defective adenovirus vector that can overexpress the ectodomain of the envelope protein of dengue virus type 2 (NGC strain) has been constructed. This virus was immunogenic in mice and elicited dengue virus type 2 specific B- and T-cell responses. Sera from immunized mice contained neutralizing antibodies that could specifically recognize dengue virus type 2 and neutralize its infectivity in vitro, indicating that this approach has the potential to confer protective immunity. In vitro stimulation of splenocytes (from immunized mice) with dengue virus type 2 resulted in a significant proliferative response accompanied by the production of high levels of gamma interferon but did not show significant changes in interleukin-4 levels. This is suggestive of a Th1-like response (considered to be important in the maturation of cytotoxic T lymphocytes that are essential for the elimination of virus-infected cells). The data show that adenovirus vectors offer a promising alternative strategy for the development of dengue virus vaccines.
Anti-Human Immunodeficiency Virus Activity of Tau Interferon in Human Macrophages: Involvement of Cellular Factors and β-Chemokines
Authors: Rogez Christine , Martin Marc , Dereuddre-Bosquet Nathalie , Martal Jacques , Dormont Dominique , Clayette Pascal
Published: November 2003

Tau interferon (IFN-τ) is a noncytotoxic type I IFN responsible for maternal recognition of the fetus in ruminants. IFN-τ inhibits human immunodeficiency virus (HIV) replication more strongly than human IFN-α, particularly in human monocyte-derived macrophages. In this study performed in human macrophages, IFN-τ efficiently inhibited the early steps of the biological cycle of HIV, decreasing intracellular HIV RNA and inhibiting the initiation of the reverse transcription of viral RNA into proviral DNA. Two mechanisms induced by IFN-τ treatment in macrophages may account for this inhibition: (i) the synthesis of the cellular antiviral factors such as 2′,5′-oligoadenylate synthetase/RNase L and MxA protein and (ii) an increased production of MIP-1α, MIP-1β, and RANTES, which are natural ligands of CCR5, the principal coreceptor of HIV on macrophages. Our results suggest that IFN-τ induces the same antiviral pathways in macrophages as other type I IFNs but without associated toxicity.
MODELING ELECTRON TRANSPORT IN MOSFET DEVICES: EVOLUTION AND STATE OF THE ART
Authors: ABRAMO ANTONIO
Published: November 2003

The progress of silicon technologies we have witnessed in the last twenty years has traced the path to the unprecedented revolution of information technologies, which has changed almost everybody's lifestyles. Apparently, this has happened with a little big help from TCAD tools. Big, because few major advancements have been achieved through the clever exploitation of non-conventional simulation tools, and because everyday device optimization deeply relies on TCAD tools. Little, because the qualitative feeling is that the technology would have progressed anyway, through the work of many highly-skilled technology experts, even without simulation guidelines. The purpose of this paper is to review the state-of-the-art of the field of the transport modeling of electron devices, trying to grasp the essence of the most relevant simulation models proposed so far, whence to contribute to spur the activity on the fundamental modeling of carrier transport.
HYDRODYNAMIC MODELING OF RF NOISE FOR SILICON-BASED DEVICES
Authors: JUNGEMANN CHRISTOPH , NEINHÜS BURKHARD , MEINERZHAGEN BERND
Published: November 2003

A 2D hydrodynamic model based on modified Langevin forces for terminal current noise in the RF range is presented for Si and SiGe devices, where all transport and noise parameters are generated by full-band Monte Carlo simulations under bulk conditions and stored in lookup tables. Since these tables have to be built only once, the accuracy of the noise model is improved without increasing the CPU time compared to models based on analytical expressions for the parameters. The accuracy of the noise model is assessed by comparison with the Monte Carlo device model and good agreement of both models is found for diffusion and generation noise. The terminal current noise of a realistic SiGe HBT is investigated and it is found that hole diffusion noise has a strong impact on the collector current noise. The limitations of the thermodynamic model, a compact model for noise, are explored by comparison with the hydrodynamic model.
GENERALIZED EXTENDED TANH-FUNCTION METHOD TO CONSTRUCT NEW EXPLICIT EXACT SOLUTIONS FOR THE APPROXIMATE EQUATIONS FOR LONG WATER WAVES
Authors: CHEN YONG , YU ZHENG
Published: November 2003

In this paper, a generalized extended tanh-function method for constructing exact solutions of nonlinear evolution equations (NEEs) is presented and implemented in a computer algebraic system. Applying the generalized method, with the aid of Maple, we consider the system of the approximate equations for long water waves and find the new more general explicit exact solutions. The properties of the new solitary wave solutions are shown by some figures.
OPTIMIZATION OF TRAFFIC LIGHTS AT CROSSROADS
Authors: HUANG DING-WEI , HUANG WEI-NENG
Published: November 2003

We study the influence of traffic lights on the traffic flow in cities. The urban traffic is simulated in the cellular automata framework. Both the deterministic and probabilistic models are discussed. The effects of speed limit and stochastic noise are analyzed. The operation of a traffic light is characterized by two parameters: signal period and phase allocation. With two traffic lights on road, one more parameter is prescribed: synchronization shift. The results of tuning these parameters are presented in the fundamental diagram. We examine the traffic flow and discuss the choice of optimized setting in different density regions.
MONTE CARLO STUDY ON THE STRUCTURAL PHASE TRANSITION IN GdMg ALLOY
Authors: CHITRA S. , MURTHY K. P. N. , RAMACHANDRAN K.
Published: November 2003

The average cohesive energy of the GdMg solid solution for various composition from x=0.10 to 0.90 has been worked out by simulation at 300 K, using Monte Carlo (MC) technique and was found that at x=0.58 there is a structural phase transition. This is compared with the available experimental results and was discussed.
NUMERICAL STUDY OF PHYSIOLOGICAL TURBULENT FLOWS THROUGH STENOSED ARTERIES
Authors: LIAO WEI , LEE T. S. , LOW H. T.
Published: November 2003

A detailed analysis on the characteristics of transitional turbulent flow over a bell-shape stenosis for a physiological pulsatile flow is presented. The comparison of the numerical solutions to three types of pulsatile flows, including a physiological flow, an equivalent pulsatile flow and a simple pulsatile flow, are made in this work. Then the effects of the Reynolds number, Womersley number and constriction ratio of stenosis on the pulsatile turbulent flow fields for the physiological flow are considered. The comparison of the three pulsatile flows shows that the flow characteristics cannot be properly estimated if an equivalent or simple pulsatile inflow is used instead of actual physiological one in the study of the pulsatile flows through arterial stenosis. The equivalent or simple pulsatile inflow can lead to higher disturbance intensity in the vicinity of the stenosis than the physiological inflow. For a physiological flow, the recirculation zones with high disturbance intensity occur mainly in the distal of the stenosis. The larger Reynolds number and severer constriction ratio may result in more complex flow field and cause some important flow variables to increase dramatically near stenosis. The higher Womersley number leads to a larger phase lag between the imposed flow rate changes and the final converged flow field in one cycle. The turbulence intensity decreases with the increase of Womersley number for the same Reynolds number.
Effect of Garlic Active Principle, Diallyl Disulfide, on Cell Viability, Lipid Peroxidation, Glutathione Concentration and its Related Enzyme Activities in Primary Rat Hepatocytes
Authors: Sheen Lee-Yan , Sheu Shiow-Fen , Tsai Shun-Jen , Meng Raymond H. C. , Lii Chong-Kuei
Published: November 2003

This study investigated the effects of various concentrations and incubation time intervals of diallyl disulfide (DADS), the active principle of garlic, on: 1. cell viability, 2. lipid peroxidation. and 3. glutathione (GSH) concentration and its related enzyme activities of rat hepatocytes. According to the results of LDH leakage and microscopic examination, 0.5 and 1 mM DADS did not significantly affect the viability of hepatocytes. However, significant decrease in cell viability according to increased LDH leakage and significant changes in morphology of hepatocytes were observed at 2 mM DADS (p < 0.05). Lipid peroxidation was also detected when the hepatocytes were treated with 2 mM DADS. At 0.5 mM DADS, a higher GSH content was found in the hepatocytes although not at a statistically significant level. 0.5 and 1 mM DADS has little effect on the activities of glutathione-S-transferase (GST) and glutathione peroxidase (GPx); however a significant decrease in GST, GPx and glutathione reductase (GRd) activities was observed at 2 mM DADS. Once the media of 2 mM DADS was replaced with fresh medium at 24 hr treatment, the activities of GST, GRd and GPx were recovered, although they were still lower than the control values.
Juzen-Taiho-To, a Japanese Herbal Medicine, Modulates Type 1 and Type 2 T Cell Responses in Old BALB/c Mice
Authors: Lijima Koji , Sun Sining , Cyong Jong-Chol , Jyonouchi Harumi
Published: November 2003

Aging is associated with skewed type 2 (T2) T cell responses that may be modulated by herbal medicines. A group of Japanese herbal medicines, so-called "Hozai," have been used to improve the physical condition of the elderly. One representative "Hozai," Juzen-Taiho-To (JTX) appears to have beneficial effects on cancer patients. In this study we hypothesized that JTX modulated skewed T2 responses in the elderly. TI and T2 responses against ovalbumin (OVA) were examined in old BALB/c mice fed JTX (0.2% w/w). We measured anti-OVA IgGI, IgG2a, and IgG2b antibody (Ab) levels after the primary and secondary OVA challenges; TI and T2 responses augment IgG2a/IgG2b Ab and IgGI/IgE Ab production, respectively. We also assessed production of TI and T2 cytokines (IFN-γ and IL-5, respectively), and co-stimulatory molecule expression by regional draining lymph node cells. JTX-fed mice had higher IgG2b Ab and IFN-γ production than controls along with lower IgG1 Ab. JTX did not alter IL-5 production or co-stimulatory molecule expression. Hoelen, an herbal component, induced similar changes. Our results indicate that JTX and Hoelen modulate T cell responses against OVA toward more balanced T1/T2 responses in old BALB/c mice. Such effects of JTX may help prevent the development of diseases associated with immunodisregulation in the elderly.
The Effect of Da-Fang-Feng-Tang on Treatment of Type II Collagen-induced Arthritis in DBA/1 Mice
Authors: Wang Lian Rong , Ishiguro Naoki , Yamada Eiji , Nishida Yoshihiro , Sato Koji , Iwata Hisashi
Published: November 2003

Da-Fang-Feng-Tang (DFFr), which is believed to be effective for treating human rheumatoid arthritis (RA), was given to DBA/1 mice at the onset of type II collagen-induced arthritis (CIA) to examine its effect. Granules of the crude DFFT extract were administered by gastric gavage at a dose of 1.6 g/kg/day for 12 weeks, starting the day CIA began. The levels of anticollagen IgG antibody were significantly decreased in the sera of the DFFT-treated group compared with the control group from weeks 2 to 7 after the onset of CIA. The severity of arthritis in the DFFT-treated group was markedly alleviated when compared with the control group. In addition, histological examination of the DFFT-treated group showed less cartilage and bone erosion. These results suggest that administration of DFFT suppressed the development of CIA in mice and support the belief that DFFT is effective in treating human RA.
Studies on the Psychosomatic Functioning of Ill-Health According to Eastern and Western Medicine 3.
Authors: Takeichi Masashi , Sato Takeshi
Published: November 2003

In this study. we examine the modality of improvement in psychosomatic function to verify the suitability of two treatment methods previously described. The subjects were nine medical students with no history of blood stasis-related illness (average age. 24.8; SD, 1.4 years) and 21 patients of our outpatient clinic (average age. 54.3; SD, 10.4 years). For purposes of our research. Kampo medication was selected based on the diagnosis and treatment of unbalanced qi, blood, and body fluid developed by the authors in their previous report. As a result, the therapeutic features of the preventive treatment group of nine medical students and the final treatment group of 21 patients of the outpatient clinic were essentially identical. There were two such features: 1. At the psychological level, this consisted of an improvement in stress-related emotional reaction, centered on anxiety and depression, and at the physiological level. this consisted of an improvement in peripheral blood circulation (an increase of the fractal dimension of the plethysmogram, p = 0.0357).2. The improvement of the foregoing psychosomatic function is related to the improvement of blood stasis (strictly speaking, vital energy stagnation and blood stasis) in Oriental medicine, and the improvement of blood rheological abnormalities in Western medicine. Therefore, this research confirmed the significance of two treatment methods proposed by the authors for stress-related illness and lifestyle disease in individuals with an anxiety-affinitive constitution.
Effects of Ginseng Radix on Sugar Absorption in the Small Intestine
Authors: Onomura Masahisa , Tsukada Hideaki , Fukuda Kazuhito , Hosokawa Masaya , Nakamura Hiroshi , Kodama Masanobu , Ohya Michihiro , Seino Yutaka
Published: November 2003

Ginseng radix (GR) is often used in traditional Japanese kampo medicine. We studied the effect of GR on glucose and maltose transport in rat and human duodenal mucosa by Using's method, and on smooth muscle movement in rat duodenal muscle by Magnus' method. GR inhibited absorption of glucose or maltose in rat and human duodenal mucosa, but increased duodenal muscle movement. It suggests that the inhibition of sugar absorption by GR is more dominant than enhancement of duodenal muscle movement by GR.
A Comparative Study of Embelia Schiperi and Embelia Keniensis on Blood Glucose and Triglycerides in Normal and Epinephrine- Induced Hyperglycemic Mice
Authors: Kato Atsushi , Miura Toshihiro , Nishiyama Yumi , Tachibana Yoko , Ohnishi Yasuhiro , Mathenge Simon G. , Albert Randrianjafy
Published: November 2003

Intraperitoneal administration of the methanol extract of Embelia schiperi (ES) to normal mice caused a significant decrease in blood glucose (p < 0.01) and a significant increase in triglycerides 4 hours after administration at 100 mg/kg (p < 0.01). The toluene fraction of Embelia keniensis methanol extract (TS) showed hypoglycemic and lipid lowering activity 7 hours after intraperitoneal administration at 100 mg/kg. In addition, TS (100 mg/kg) administration significantly decreased blood glucose in epinephrine-induced hyperglycemic mice (p < 0.01). Moreover, ES tended to increase while TS tended to decrease the blood triglycerides in epinephrine-induced hyperglycemic mice. On the other hand, no changes in blood cholesterol were observed after the administration of ES or TS in normal and epinephrine-induced hyperglycemic mice. We found that two species from Embelia, ES and TS, have different activities on blood glucose and triglycerides in normal and epinephrine-induced hyperglycemic mice.
Radioprotective Effects of Two Traditional Chinese Medicine Prescriptions: Si-Wu-Tang and Si-Jun-Zi-Tang
Authors: Lee Song-Eun , Oh Heon , Yang Jung-Ah , Jo Sung-Kee , Byun Myung-Woo , Yee Sung-Tae , Kim Sung-Ho
Published: November 2003

We performed this study to determine the effect of Si-Wu-Tang, a basic prescription of traditional Oriental medicine as a blood-building decoction (Chinese medical concept: Bu-Xie), Si-Jun-Zi-Tang, a basic prescription as an energy tonic (Chinese medical concept: Bu-Qi) and its major ingredients on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice irradiated with high and low dose of γ-irradiation. Si-Wu-Tang administration before irradiation protected the jejunal crypts (p < 0.0005), increased the formation of endogenous spleen colonies (p < 0.05) and reduced the frequency of radiation-induced apoptosis (p < 0.05). In an experiment on the effect of ingredients of Si-Wu-Tang, the result indicated that extract of Danggui and Baishaoyao might have a major radioprotective effect. The radioprotective effect of Si-Jun-Zi-Tang and its ingredients were not as significant as that of Si-Wu-Tang. Although the mechanisms of this inhibitory effect remain to be elucidated, these results indicate that Si-Wu-Tang might be a useful radioprotector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the protective nature of Si-Wu-Tang extract and its ingredients.
AN ISOTROPIZATION MECHANISM IN BIANCHI I MODEL
Authors: FLICHE H. H. , TRIAY R. , NOVELLO M. , De FREITAS L. R.
Published: November 2003

We ask whether the problem on the initial conditions in Cosmology can be solved if an efficient elimination mechanism of the anisotropy was present at earlier epochs. We explore the consequences of the existence of an epoch in which the material content of the Universe was represented by an stress-energy tensor possessing anisotropic pressure which depends nonlinearly on the expansion parameter. We show that for selected candidate behaviors the associated shear pass through a maximum and vanishes asymptotically. We use the Hamiltonian formalism to define a constant of motion which enables us to classify the cosmological world-models.
REMOVAL OF THE DIFFERENCE BETWEEN CHARACTERISTIC AND REAL AGE IN THE MAGNETAR MODEL FROM THE ANALYSIS OF SPECTRAL PROPERTIES OF AXPs, SGRs AND DRQNSs
Authors: GUSEINOV OKTAY H. , TAŞKIN ÖZGÜR , YAZGAN EFE , TAGIEVA SEVINÇ
Published: November 2003

We put together many observational data of SGRs and AXPs and analyze them with the main purpose to remove contradiction between the real age of these objects and their characteristic times of period change. This work indicates that SGRs and AXPs are neutron stars with magnetic fields up to ~3×1014 G at birth, which is less than the possible value in the existing magnetar model. These neutron stars undergo star-quakes and reconnection of magnetic field occurs from time to time. As a result of these processes plasma is ejected from the NS and propeller mechanism starts to work. Due to the propeller effect [Formula: see text] increases and τ decreases. Indeed, high [Formula: see text] values are observed in SGRs and in half of the AXPs. Then, for a long time NS looses its activity, its [Formula: see text] decreases, τ increases and rapid cooling begins. Each NS stage (AXP, SGR, dim) may occur once or several times until the spin period of the neutron star becomes P >10–12 s . At the transition period to the SGR and AXP stages, the magnetic field component perpendicular to the rotation axis may increase up to 2–3 times. Observational data and mainly the data of AXP1E1048-5937 and DRQNS RX J1308.8+2127 support this idea.
1.3 μm AlGaInAs-InP POLARIZATION-INSENSITIVE SEMICONDUCTOR OPTICAL AMPLIFIER WITH TENSILE STRAINED WELLS GROWN BY MOVPE
Authors: MA HONG , YI XINJIAN , CHEN SIHAI
Published: November 2003

We demonstrate a polarization-insensitive multiple-quantum-well optical amplifer for 1.3 μm wavelength in AlGaInAs-InP material system, using three tensile strained wells with strain of 0.36% in the active region. The amplifiers were fabricated forming ridge waveguide structure, which showed excellent polarization insensitivity (less than 0.6 dB) over the entire range of wavelength (1.28 μm ~ 1.34 μm) and a gain of 22.5 dB at the bias current of 200 mA and 1304 nm wavelength.
Hypo-osmotic or Ca2+-rich external conditions trigger extra contractile vacuole complex generation inParamecium multimicronucleatum
Authors: Iwamoto Masaaki , Allen Richard D. , Naitoh Yutaka
Published: November 2003

The freshwater ciliated protozoan, Paramecium multimicronucleatum,usually possesses two contractile vacuole complexes (CVCs). The number of CVCs in a single cell, however, may vary from 1 to 7. We found that the number of cells that have more than two CVCs increased after the cells were exposed to a hypo-osmotic or a high Ca2+ condition. It is assumed that the biological significance of this increase in the number of CVCs is to enhance the cell's ability to eliminate excess water or Ca2+ from the cytosol. An extra CVC was either generated de novo in the posterior region of the cell or, when in the anterior region, by binary fission of the anterior CVC. Generation of these extra CVCs was not inhibited by aphidicolin,a potent inhibitor of DNA synthesis in the micronuclei of Paramecium,even though normal duplication of the CVC that accompanies normal cell division was completely inhibited by this inhibitor. These results suggest that generation of extra CVCs is controlled by a hypothetical regulatory mechanism that is activated either by a hypo-osmotic or by a Ca2+-rich condition and that differs from the regulatory mechanism that governs normal CVC duplication during cell division.
The comparative energetics and growth strategies of sympatric Antarctic and subantarctic fur seal pups at Îles Crozet
Authors: Arnould J. P. Y. , Luque S. P. , Guinet C. , Costa D. P. , Kingston J. , Shaffer S. A.
Published: November 2003

The period of maternal dependence is a time during which mammalian infants must optimise both their growth and the development of behavioural skills in order to successfully meet the demands of independent living. The rate and duration of maternal provisioning, post-weaning food availability and climatic conditions are all factors likely to influence the growth strategies of infants. While numerous studies have documented differences in growth strategies at high taxonomic levels, few have investigated those of closely related species inhabiting similar environments. The present study examined the body composition, metabolism and indices of physiological development in pups of Antarctic fur seals (Arctocephalus gazella) and subantarctic fur seals (Arctocephalus tropicalis), congeneric species with different weaning ages (4 months and 10 months, respectively), during their overlap in lactation at a sympatric breeding site in the Iles Crozet. Body lipid reserves in pre-moult pups were significantly greater(t28=2.73, P<0.01) in subantarctic (26%) than Antarctic fur seals (22%). Antarctic fur seal pups, however, had significantly higher (t26=3.82, P<0.001) in-air resting metabolic rates (RMR; 17.1±0.6 ml O2 kg-1min-1) than subantarctic fur seal pups (14.1±0.5 ml O2 kg-1 min-1). While in-water standard metabolic rate (SMR; 22.9±2.5 ml O2 kg-1min-1) was greater than in-air RMR for Antarctic fur seal pups(t9=2.59, P<0.03), there were no significant differences between in-air RMR and in-water SMR for subantarctic fur seal pups(t12=0.82, P>0.4), although this is unlikely to reflect a greater ability for pre-moult pups of the latter species to thermoregulate in water. Pup daily energy expenditure was also significantly greater (t27=2.36, P<0.03) in Antarctic fur seals (638±33 kJ kg-1 day-1) than in subantarctic fur seals (533±33 kJ kg-1 day-1), which corroborates observations that pups of the former species spend considerably more time actively learning to swim and dive. Consistent with this observation is the finding that blood oxygen storage capacity was significantly greater(t9=2.81, P<0.03) in Antarctic (11.5%) than subantarctic fur seal (8.9%) pups. These results suggest that, compared with subantarctic fur seals, Antarctic fur seal pups adopt a strategy of faster lean growth and physiological development, coupled with greater amounts of metabolically expensive behavioural activity, in order to acquire the necessary foraging skills in time for their younger weaning age.
Influence of salinity on the localization of Na+/K+-ATPase,Na+/K+/2Cl- cotransporter (NKCC) and CFTR anion channel in chloride cells of the Hawaiian goby (Stenogobius hawaiiensis)
Authors: McCormick Stephen D. , Sundell Kristina , Björnsson Björn Thrandur , Brown Christopher L. , Hiroi Junya
Published: November 2003

Na+/K+-ATPase,Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) are the three major transport proteins thought to be involved in chloride secretion in teleost fish. If this is the case, the levels of these transporters should be high in chloride cells of seawater-acclimated fish. We therefore examined the influence of salinity on immunolocalization of Na+/K+-ATPase, NKCC and CFTR in the gills of the Hawaiian goby (Stenogobius hawaiiensis). Fish were acclimated to freshwater and 20‰ and 30‰ seawater for 10 days. Na+/K+-ATPase and NKCC were localized specifically to chloride cells and stained throughout most of the cell except for the nucleus and the most apical region, indicating a basolateral/tubular distribution. All Na+/K+-ATPase-positive chloride cells were also positive for NKCC in all salinities. Salinity caused a slight increase in chloride cell number and size and a slight decrease in staining intensity for Na+/K+-ATPase and NKCC, but the basic pattern of localization was not altered. Gill Na+/K+-ATPase activity was also not affected by salinity. CFTR was localized to the apical surface of chloride cells, and only cells staining positive for Na+/K+-ATPase were CFTR-positive. CFTR-positive cells greatly increased in number (5-fold), area stained (53%) and intensity (29%)after seawater acclimation. In freshwater, CFTR immunoreactivity was light and occurred over a broad apical surface on chloride cells, whereas in seawater there was intense immunoreactivity around the apical pit (which was often punctate in appearance) and a light subapical staining. The results indicate that Na+/K+-ATPase, NKCC and CFTR are all present in chloride cells and support current models that all three are responsible for chloride secretion by chloride cells of teleost fish.
Organic–Inorganic Cooperative Molecular Recognition in Nanostructure of Alkyl-grafted MCM-41
Authors: Inumaru Kei , Inoue Yuta , Kakii Shintaro , Nakano Tomoyasu , Yamanaka Shoji
Published: November 2003

Molecules having hydrophobic and hydrophilic groups such as 4-n-heptylaniline and 4-nonylphenol, an endocrine disrupter, fit the organic–inorganic nanostructure in alkyl-grafted MCM-41, interacting with the inorganic walls as well as the organic moiety, and thus the adsorbent achieves high molecular adsorption selectivity.
Preparation of Gold Nanoplates by a Microwave-polyol Method
Authors: Tsuji Masaharu , Hashimoto Masayuki , Nishizawa Yuki , Tsuji Takeshi
Published: November 2003

Triangular, square, and hexagonal gold nanoplates with diameters of 30–90 nm have been prepared through a microwave-polyol method. These nanoplates gave new plasmon band of Au in the 550–800 nm region. It was concluded that nonthermal effect plays a significant role for the formation of Au nanoplates under microwave irradiation.
Inclusion Complex Formation and Hydrolysis of Lactones by Cyclodextrins
Authors: Takashima Yoshinori , Kawaguchi Yoshinori , Nakagawa Shinya , Harada Akira
Published: November 2003

Cyclodextrins (CDs) have been found to form inclusion complexes with lactones in aqueous solutions and/or in the solid states; hydrolysis of lactones has been found to be suppressed or promoted by CDs according to the combination of lactones and CD.
Synthesis and Characterization of Ni(OH)2 Single-crystal Nanorods
Authors: Liang Jiahe , Li Yadong
Published: November 2003

A template-free hydrothermal method to Ni(OH)2 single-crystal nanorods were successfully established based on the 2-D layered structures of Ni(OH)2. The obtained Ni(OH)2 nanorods were 40–90 nm in diameters and 1–3 μm in lengths. It is interesting that Ni(OH)2 nanorods would be converted into NiO nanorings when they were annealed at 500 °C for 6 h.
Grocery Price Setting and Quantity Surcharges
Authors: Sprott David E. , Manning Kenneth C. , Miyazaki Anthony D.
Published: November 2003

Quantity surcharges occur when the unit price of a brand's larger package is higher than the unit price of the same brand's smaller package. The authors examine how price-setting practices in the grocery industry help explain the existence of quantity surcharges. Two studies support the authors’ contention that common pricing practices aimed at establishing a favorable store–price image can result in quantity surcharges. First, an experiment shows that consumer demand and the importance price setters place on establishing a low store–price image have an interactive effect on price-setting behavior. Second, an examination of retail sales volume, price, and cost data suggests that such price-setting reactions can result in quantity surcharges when certain asymmetries in demand exist across package sizes. The authors also discuss managerial and public policy implications along with areas for further study.
Mass-Communicated Prediction Requests: Practical Application and a Cognitive Dissonance Explanation for Self-Prophecy
Authors: Spangenberg Eric R. , Sprott David E. , Grohmann Bianca , Smith Ronn J.
Published: November 2003

Marketers often promote socially beneficial actions or discourage antisocial behaviors to the benefit of their firms, target markets, and society as a whole. One means by which marketers accomplish such influence is a technique referred to as the “self-prophecy effect,” or the behavioral influence of a person making a self-prediction. Researchers have yet to establish the efficacy of self-prophecy in influencing large target markets. In addition, the theoretical mechanism underlying the effect remains in question. The authors report two field studies that demonstrate successful application of self-prophecy through mass-communicated prediction requests. Furthermore, in three laboratory experiments, the authors provide theoretical support for a dissonance-based explanation for self-prophecy, and they discuss practical implications for marketers interested in influencing socially normative behavior.
Market Situation Interpretation and Response: The Role of Cognitive Style, Organizational Culture, and Information Use
Authors: White J. Chris , Varadarajan P. Rajan , Dacin Peter A.
Published: November 2003

Improving marketing decision making requires a better understanding of the factors that influence how managers interpret and respond to a market situation. Building on extant literature, the authors develop a model that delineates antecedents of and responses to the interpretation of a market situation. Using case-scenario methodology, the authors test the model in the context of a marketing decision (annual advertising and promotion budget recommendation) with data collected from a nationwide sample of hospital marketing executives. The results of the partial least squares analysis show that (1) cognitive style, organizational culture, and information use affect the extent to which managers perceive a given market situation as one in which they can control the outcomes of their decision; (2) the more managers perceive a situation as controllable, the more they appraise that situation as an opportunity; and (3) the more managers appraise a situation as an opportunity, the greater is the magnitude of their response.
An Exploratory Study of the Introduction of Online Reverse Auctions
Authors: Jap Sandy D.
Published: November 2003

Buyers are increasingly turning to online reverse auctions in their negotiations with suppliers. How do these price competition mechanisms affect buyer–supplier relationships? The author considers this question in the context of a quasi experiment involving six online reverse auctions conducted in the supply base of a major industrial buyer. The results indicate that these auctions increase both new and current suppliers’ beliefs that buyers act opportunistically, particularly in open-bid auctions. Current suppliers are generally more willing than new suppliers to make dedicated investments toward the buyer. Paradoxically, in sealed-bid auctions, both current and new suppliers increase their willingness to make dedicated investments toward the buyer. Although these auctions can yield cost savings, the savings are category specific and are not systematically related to an open- or sealed-bid format. The author also discusses implications for the use of online reverse auctions in industrial sourcing activities.
Coding for Magnetic Recording Channels
Authors: Weng Lih‐Jyh
Published: November 2003

A brief history of coding approaches employed in magnetic recording disk drives is first reviewed. This is followed by a simple example of using the most widely used Reed‐Solomon codes to illustrate the concepts and terminology frequently used in disk drives. Important considerations in selecting appropriate decoding algorithm are explained. Implementation issues are discussed. Synchronization techniques, code performance based on error rate computation, interleaving of code block within a recording sector, and error‐detecting code issues are also addressed. Finally, coding approaches for magnetic tape drives and RAID systems are discussed.
Surface Acoustic Wave Filters
Authors: Das Pankaj K. , Filkins Robert J.
Published: November 2003

Surface acoustic wave filters are an essential part of many telecommunication systems, from cell phones to GPS receivers. This chapter presents the fundamentals of surface acoustic wave device operation and their application to telecommunication systems. The main types of ultrasonic acoustic waves are described, followed by a discussion of the device building blocks. Next, the design of surface acoustic wave filters is outlined, and specific design examples are given. Finally, several detailed application examples are provided, summarizing the use of surface acoustic filters in telecommunication systems.
Very High‐Speed Digital Subscriber Lines (VDSLs)
Authors: Cioffi J.
Published: November 2003

Very high‐speed Digital Subscriber Lines (VDSL) is the most recent in VDSL service offerings, allowing speeds to many tens of megabits per second in both directions on a single phone line of length less than 2 km. This chapter overviews VDSL history and standards while also describing some of the key technologies used at the implementation level. Some reference to the emerging VDSL application area of Ethernet‐in‐the‐First‐Mile (EFM) is also provided.
Orthogonal Frequency‐Division Multiplexing
Authors: Cimini Leonard J. , Greenstein Larry J.
Published: November 2003

The permissible data rate of a digital communications link is limited by the available bandwidth and also by power and noise. We present the basic concepts and then discuss the numerous communications systems, past and present, that have used some form of multicarrier transmission. We then discuss time variations in the channel, as well as frequency offset, phase noise, and timing errors. Next, we the look at the large amplitude fluctuations characteristic of a multicarrier signal and the serious problems when transmitting through a nonlinearity, such as the transmit power amplifier. Finally, we discuss cyclic extension and windowing, two techniques devised to get the most value out of orthogonal frequency‐division multiplexing (OFDM).
Blind Multiuser Detection
Authors: Wang Xiaodong
Published: November 2003

There are primarily two approaches to blind multiuser detection, namely, the direct matrix inversion (DMI) approach and the subspace approach. In this article, we present batch algorithms and adaptive algorithms under both approaches. We first treat the simple synchronous CDMA channels and present the main techniques for blind multiuser detection. We then generalize these methods to the more general asynchronous CDMA channels with multipath effects.
Atmospheric Radiowave Propagation
Authors: Raemer Harold
Published: November 2003

This article is a brief summary of the mode of radio wave propagation that is used in wireless communication systems operating at frequencies between 300 MHz and 30 GHz. It begins with a discussion of line‐of‐sight propagation in free‐space, then examines the effects on the propagating waves of reflection from the earth's surface, the earth's curvature, and atmospheric refraction and attenuation. Next we discuss the effects of surface roughness and the presence of natural and man‐made obstacles in the propagation path, which causes diffraction and scattering of the waves. The remaining portion of the article covers propagation models which have been useful in prediction of path losses for planning and design of wireless links, and which contain many of the phenomena mentioned above. The article includes many references on the topics covered and on some topics that are only briefly mentioned.
Cellular Communications Channels
Authors: Mämmelä Aarne , Järvensivu Pertti
Published: November 2003

Linear channel models for terrestrial outdoor mobile cellular systems including multipath fading and shadowing are summarized in this chapter. In microcells the cell radius is about 0.1 km to 1 km and in macrocells the cell radius is about 1 km to 30 km. Such systems typically work in the frequency range from about 1 GHz to 2 GHz. The bandwidth of the transmitted signals is in the order of 100 kHz to 1 MHz. The second order statistics of the typical Rayleigh fading wide‐sense stationary uncorrelated scattering (WSSUS) channel are described by the scattering function, which is the average power output as a function of the time delay and the Doppler shift parameter. The amplitudes of the multipath components can also be assumed to be Ricean or Nakagami‐m distributed. Shadowing is normally assumed to be lognormal. The results are generalized to the two‐dimensional case where the direction of arrival is included in addition to the delay. The channel impulse response is measured usually by using m‐sequences and correlation. Most practical channels are shown to be measurable. Measurements show that the the delay spreads in urban areas are from 1 ms to 2 ms and in mountainous areas from 100 ms to 150 ms. The Doppler spread depends on the carrier frequency and the velocity of the mobile station. Channel simulators are based on either stored channel impulse responses, ray tracing models or stochastic parametric models, and they are implemented by hardware or software by using transversal filters. Models are specified by different standardization organizations. At the end of the chapter recent trends are summarized, including larger carrier frequencies, increased bandwidths, three‐dimensional and nonstationary models, and models with multiple inputs and outputs.
HiddenMarkov Models
Authors: Juang Biing‐Hwang
Published: November 2003

A hidden Markov model is a mathematical formalism that allows modeling of a stochastic system, which may undergo characteristic changes at uncertain times. It is often called a doubly stochastic process in which a Markov chain governs the characteristic change of the system and each state of the Markov chain is associated with a stochastic process or distribution, which supports the random nature of the observation. The formalism is also referred to asprobabilistic functions of Markov processes. In this article, we define this stochastic modeling technique, elaborate its key problems and solutions, and show, as a simple example, how this technique can be applied to real‐world problems such as automatic speech recognition for communication services.