bluuebunny/crossref_metadata_2025 huggingface dataset:
A model for crystal growth during metal induced lateral crystallization of amorphous silicon
Authors: Joshi Amol R. , Krishnamohan Tejas , Saraswat Krishna C.
Published: December 2002

In this work a model has been proposed to predict crystal growth with metal induced lateral crystallization (MILC) of thin films of amorphous silicon (α-Si). Previous work by different groups using nickel for MILC reports crystal growth rate increasing as well as decreasing with time. Based on their experimental results, we propose that part or all of nickel in newly crystallized Si comes from the NiSi2 moving front which reduces its thickness. With a few assumptions, relation between rate of crystal growth and rate of NiSi2 thinning is obtained. Two regimes, diffusion limited growth and surface reaction limited growth are proposed for MILC to explain increasing and decreasing crystal growth rates. After calculating crystal growth as a function of time, the proposed model is compared with experimental data.
On the physical mechanisms of liquid-assisted laser cleaning
Authors: Kim Dongsik , Lee Joochul
Published: December 2002

This communication addresses two questions regarding the physical mechanisms of the liquid-assisted laser cleaning: (1) What is the correlation between the cleaning force and bubble dynamics in the explosive vaporization of the liquid film? (2) How does the liquid-film thickness affect the cleaning process? Transient displacement of the cleaning target is measured by optical interferometry for in situ detection of the cleaning force. Time-resolved visualization and optical reflectance probing are conducted for monitoring the behavior of the liquid film in the cleaning process, with emphasis on the effect of liquid-film thickness. The results prove that cleaning force is generated when the bubble nuclei initially grow in the strongly superheated liquid. The liquid-film thickness is shown to be irrelevant to the origin of the force though it affects the dynamics of liquid plume and possibly changes the cleaning efficiency.
Model-dielectric-function analysis of ion-implanted Si(100) wafers
Authors: Adachi Sadao , Mori Hirofumi , Takahashi Mitsutoshi
Published: December 2002

Optical properties of Si+, P+, and Ar+ ion-implanted Si(100) wafers have been studied using spectroscopic ellipsometry. The Si+, P+, and Ar+ ions are implanted at 150 keV with fluences ranging from 1×1014 to 2×1015 cm−2 at room temperature. A model dielectric function (MDF), which was developed for modeling the optical constants of perfectly crystalline semiconductors, has been applied to investigate the optical response of the ion-implanted Si(100) wafers. The MDF analysis indicates a distinct structural transition from the crystalline to amorphous phase at some ion fluences around 1014–1015cm−2. Since the critical points do not have any validity in amorphous material, the band gaps used in the MDF are not a result of the Bragg gaps at the Brillouin-zone boundaries, but are considered to arise from the short-range order determined by the covalent bonding. Using these results, we obtain an expression, D=(1.6×108/M)2.2 cm−2 which enables us to estimate the crystalline-amorphous phase transition fluence D for silicon wafers implanted with optional ion species of mass number M. No clear change in the morphology of silicon surface after ion implantation has also been confirmed by atomic force microscopy.
Observation of faster-than-diffusion magnetic field penetration into a plasma
Authors: Arad R. , Tsigutkin K. , Maron Y. , Fruchtman A. , Huba J. D.
Published: December 2002

Spatially and temporally resolved spectroscopic measurements of the magnetic field, electron density, and turbulent electric fields are used to study the interaction between a pulsed magnetic field and a plasma. In the configuration studied (known as a plasma opening switch) a 150 kA current of 400 ns-duration is conducted through a plasma that fills the region between two planar electrodes. The time-dependent magnetic field, determined from Zeeman splitting, is mapped in three dimensions, showing that the magnetic field propagation is faster than expected from diffusion based on the Spitzer resistivity. Moreover, the measured magnetic field profile and the amplitude of turbulent electric fields indicate that the fast penetration of the magnetic field cannot be explained by an anomalously high resistivity. On the other hand, the magnetic field is found to penetrate into the plasma at a velocity that is independent of the current-generator polarity, contradictory to the predictions of the Hall-field theory. A possible mechanism, independent of the current-generator polarity, based on the formation of small-scale density fluctuations that lead to field penetration via the Hall mechanism, is presented. It is suggested that these density fluctuations may result from the effect of the unmagnetized Rayleigh–Taylor instability on the proton plasma that undergoes a large acceleration under the influence of the magnetic field pressure.
Rigorous calculation of electric field effects on the free energy change of the electron transfer reaction
Authors: Seki Kazuhiko , Traytak S. D. , Tachiya M.
Published: December 2002

We theoretically investigate the effect of an external electric field on the free energy change of electron transfer reaction in polar solvents. The external electric field produces polarization both on the solutes and in the solvent. Since the polarization produced on the solute differs from that in the solvent, apparent surface charge is created on the surface of the solutes. The polarization charge on the surface of the solutes interacts with the charge associated with the electron transfer. The free energy change of the reaction including such effect is calculated rigorously. A simple formula is derived and compared to the exact result in the case of spherical solutes in the dielectric continuum media. Only slight deviations are observed for any values of the solvent polarity and of the ratio between the radii of the donor and the acceptor molecules. In addition, we also applied the same method to evaluate the reorganization energy rigorously: The Marcus expression for the reorganization energy is an approximate one. The accuracy of the Marcus expression is assessed by comparing it with the exact result.
Polarized photoreflectance spectra of excitonic polaritons in a ZnO single crystal
Authors: Chichibu S. F. , Sota T. , Cantwell G. , Eason D. B. , Litton C. W.
Published: December 2002

Exciton–polariton structures in a high-quality bulk ZnO single crystal were resolved at 8 K by means of polarized photoreflectance (PR) and photoluminescence measurements. The energies of the PR resonances corresponded to those of the upper and lower exciton–polariton branches, where A, B, and C excitons couple simultaneously to an electromagnetic wave. Longitudinal-transverse splitting of ground-state exciton polaritons and resonances due to the first excited states of respective excitons were observed due to the large oscillator strength. Photoluminescence peaks due to the corresponding polarion branches were clearly resolved. The valence-band ordering was confirmed to be A-Γ9v, B-Γ7vu, and C-Γ7vl.
Degradation of operation mode purity in a gyrotron with an off-axis electron beam
Authors: Airila M. I.
Published: December 2002

The two-dimensional self-consistent time-dependent theory of beam–wave interaction in gyrotron resonators has been modified to account for eccentricity of the annular hollow electron beam. Numerical analysis yields the effect of beam eccentricity on the previously known limiting values of the azimuthal index of the mode, beyond which stationary single-mode operation becomes impossible.
Electron trapping, storing, and emission in nanocrystalline Si dots by capacitance–voltage and conductance–voltage measurements
Authors: Huang Shaoyun , Banerjee Souri , Tung Raymond T. , Oda Shunri
Published: December 2002

Temperature and frequency dependent electrical properties of SiO2/nanocrystalline Si (nc-Si)/SiO2 sandwich structures have been studied. A clear shift of the capacitance–voltage and conductance–voltage characteristics toward positive gate voltage suggests electron trapping in an nc-Si dot. The role of interface states and deep traps in our devices has also been thoroughly examined and shown to be unimportant on the overall device performance. The discharging process is found to be logarithmic with time and weakly temperature dependent. The long memory retention time and the logarithmic time dependence of charge loss in the dots are explained by a buildup of opposing electric field in the tunnel oxide, which hinders the discharge of electrons remaining in the dots.
Luminescence study of (112̄0) GaN film grown by metalorganic chemical-vapor deposition
Authors: Chen Zhen , Lu Da-Cheng , Liu Xianglin , Wang Xiaohui , Han Peide , Wang Du , Yuan Hairong , Wang ZhanGuo , Li GuoHua , Fang ZaiLi
Published: December 2002

Investigations on photoluminescence properties of (112̄0) GaN grown on (11̄02) Al2O3 substrate by metalorganic chemical-vapor deposition are reported. Several emission lines not reported before are observed at low temperature. The sharp peak at 3.359 eV is attributed to the exciton bound to the neutral acceptor. Another peak at 3.310 eV represents a free-to-bound, probably a free electron-to-acceptor, transition. The 3.241 and 3.170 eV lines are interpreted as phonon replica lines of the 3.310 eV line. The phonon energy is 70 meV, consistent with the energy of transverse optical E1 phonon. The optical properties of the lines are analyzed.
Wigner-like crystallization of Anderson-localized electron systems with low electron densities
Authors: Slutskin A. A. , Kovtun H. A. , Pepper M.
Published: December 2002

We consider an electron system under conditions of strong Anderson localization, taking into account interelectron long-range Coulomb repulsion. We establish that at sufficiently low electron densities and sufficiently low temperatures the Coulomb electron interaction brings about ordering of the Anderson-localized electrons into a structure that is close to an ideal (Wigner) crystal lattice, provided the dimension of the system is >1. This Anderson–Wigner glass (AWG) is a new macroscopic electron state that, on the one hand, is beyond the conventional Fermi glass concept, and on the other hand, qualitatively differs from the known “plain” Wigner glass (inherent in self-localized electron systems) in that the random slight electron displacements from the ideal crystal sites depend essentially on the electron density. With increasing electron density the AWG is found to turn into the plain Wigner glass or Fermi glass, depending on the width of the random spread of the electron levels. It is shown that the residual disorder of the AWG is characterized by a multivalley ground-state degeneracy akin to that in a spin glass. Some general features of the AWG are discussed, and a new conduction mechanism of a creep type is predicted.
Photoluminescence studies on InGaN/GaN multiple quantum wells with different degree of localization
Authors: Hao M. , Zhang J. , Zhang X. H. , Chua S.
Published: December 2002

It has been found, by using photoluminescence (PL) studies, that both the localized states and nonradiative recombination centers in In0.06Ga0.94N/GaN multiple quantum wells (MQWs) can be greatly suppressed by inserting a monolayer of AlN before the growth of each well layer. While inserting a monolayer of AlN before each well layer does not have any effect on the growth rate or on the indium content of MQWs, it does improve room-temperature PL intensity of the In0.06Ga0.94N/GaN MQWs. The physics behind the suppression of localized states and nonradiative recombination centers is discussed.
Magnetic and martensitic phase transitions in ferromagnetic Ni–Ga–Fe shape memory alloys
Authors: Oikawa K. , Ota T. , Ohmori T. , Tanaka Y. , Morito H. , Fujita A. , Kainuma R. , Fukamichi K. , Ishida K.
Published: December 2002

Ferromagnetic shape memory alloys with a body-centered-cubic ordered structure in a Ni–Ga–Fe system have been developed. The alloys with the composition range of Ni 27 at. % Ga (20–22 at. %)Fe exhibit a thermoelastic martensitic transformation from a B2 and/or an L21 parent to a martensite phase, with a seven-layer modulated (14M) and a five-layer modulated (10M) structure, in the ferromagnetic state. The parent phase transforms from the B2 to the L21 structure at about 970 K during cooling, and the degree of the L21 order in the parent phase is increased by annealing at 773 K, resulting in the increase of both the martensite starting and the Curie temperatures. The ductility of these alloys is improved by introducing of a small amount of a γ-phase solid solution. Consequently, we can conclude that the present alloys are promising for ferromagnetic shape memory alloys.
Thickness of the near-interface regions and central bulk ohmic resistivity in lead lanthanum zirconate titanate ferroelectric thin films
Authors: Chu D. P. , Zhang Z. G. , Migliorato P. , McGregor B. M. , Ohashi K. , Hasegawa K. , Shimoda T.
Published: December 2002

We have developed a method to separate the low-resistive near-interface regions (NIRs) from the high-resistive central bulk region (CBR) in a ferroelectric thin film. The NIR thickness and the CBR resistivity can thus be accurately determined. Using lanthanum-doped lead zirconate titanate films as an example, we show that the total thickness of the NIRs depends only on the electrode materials in use (Ir and Pt), while the CBR resistivity depends only on the impurity doping levels (La=1.5% and 3%). The fact that the NIR is much narrower when Pt electrodes are used instead of Ir, and that the NIR resistivity is always considerably lower than the central bulk, suggest that the NIRs is probably originated from material nonstoichiometry/defects rather than the band bending at metal/insulator interfaces.
Correlation of resistivity with zinc content in a vapor grown (Cd,Zn)Te:Se
Authors: Corregidor V. , Diéguez E. , Castaño J. L. , Fiederle M. , Babentsov V. , Fauler A. , Benz K.
Published: December 2002

We report the possibility to grow semi-insulating (Cd,Zn)Te:Se crystals by the modified Markov method (MMM) from the vapor phase. When oriented Cd(Te,Se) seed material was used for the growth, lattice matching and doping with Se resulted in an increase of resistivity up to several units of 109 Ω cm. A homogenous Zn distribution was also observed. The content of Se and Zn in the seed and grown crystals was determined by photoluminescence and energy dispersive analysis by x ray measurements. Resistivity and Zn concentration maps show a good spatial correlation in which the highest values of resistivity correspond to the areas of the highest Zn concentration. The main part of the crystals demonstrate a low extinction coefficient in the IR spectral region, except for the Zn inhomogeneity region.
Development of microthermophotovoltaic system
Authors: Yang W. M. , Chou S. K. , Shu C. , Li Z. W. , Xue H.
Published: December 2002

A power microelectromechanical concept, a microthermophotovoltaic system, is described in this work. The system uses hydrogen as fuel and is capable of delivering 4.5 W of electrical power to a microcombustor 0.1 cm3 in volume. It does not involve any moving parts. Its fabrication and assembly are relatively easy. As a result, it can be more commonly used in commercial electronics and microdevices.
A high frequency chaotic signal generator: A demonstration experiment
Authors: Roy Prodyot Kumar , Basuray Arijit
Published: December 2002

We discuss a simple oscillator that is capable of producing chaotic as well as periodic signals. The circuit design is straightforward and can easily be implemented in a standard undergraduate physics laboratory. The signal generator is suitable for demonstrating how the nonlinearity of the circuit elements can affect the output of an electronic device.
Incidence of Invasive Breast Cancer by Hormone Receptor Status From 1992 to 1998
Authors: Li Christopher I. , Daling Janet R. , Malone Kathleen E.
Published: December 2002

Purpose: Between 1987 and 1998, breast cancer incidence rates rose 0.5%/yr in the United States. A question of potential etiologic and clinical importance is whether the hormone receptor status of breast tumors is also changing over time. This is because hormone receptor status may reflect different etiologic pathways and is useful in predicting response to adjuvant therapy and prognosis.

Methods: Age-adjusted, age-specific breast cancer incidence rates by estrogen receptor (ER) and progesterone receptor (PR) status from 1992 to 1998 were obtained and compared from 11 population-based cancer registries in the United States that participate in the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program.

Results: From 1992 to1998, the overall proportion of breast cancers that were ER-positive and PR-positive increased from 75.4% to 77.5% (P = .0002) and from 65.0% to 67.7% (P < .0001), respectively, continuing trends observed before 1992. These increases were limited to women 40 to 69 years of age. The proportions of ER-positive/PR-positive tumors increased from 56.7% to 62.3% (P = .0010) among 40- to 49-year-olds, from 58.0% to 63.2% (P = .0002) among 50- to 59-year-olds, and from 63.2% to 67.9% (P = .0020) among 60- to 69-year-olds.

Conclusion: From 1992 to 1998, the proportion of tumors that are hormone receptor–positive rose as the proportion of hormone receptor–negative tumors declined. Because the incidence rates of hormone receptor–negative tumors remained fairly constant over these years, the overall rise in breast cancer incidence rates in the United States seems to be primarily a result of the increase in the incidence of hormone receptor–positive tumors. Hormonal factors may account for this trend.
Thalidomide Alone or With Dexamethasone for Previously Untreated Multiple Myeloma
Authors: Weber Donna , Rankin Kim , Gavino Maria , Delasalle Kay , Alexanian Raymond
Published: December 2002

Purpose: To evaluate the activity of thalidomide in patients with asymptomatic multiple myeloma and of thalidomide-dexamethasone in patients with previously untreated symptomatic myeloma.

Patients and Methods: Twenty-eight patients with previously untreated asymptomatic myeloma were treated with thalidomide 100 to 200 mg orally (PO) at bedtime (qhs) with serial increments of 50 to 100 mg at weekly intervals, as tolerated to a maximum of 600 mg PO qhs. Forty consecutive previously untreated patients with symptomatic myeloma were also treated as above (maximum dose 400 mg) and received dexamethasone 20 mg/m2 for 4 days beginning on days 1, 9, and 17; the second and third cycles of repeated dexamethasone were begun on day 30. Both groups of patients were treated for at least 3 months.

Results: The response rate was 36% for patients treated with thalidomide alone and 72% for patients treated with thalidomide-dexamethasone, the latter including complete remission in 16% of patients. The median time to remission was 4.2 months with thalidomide alone and 0.7 months with thalidomide-dexamethasone. Grade 3 toxicity included infections (nine patients) and thrombotic/embolic events (seven patients). Five deaths have occurred as a result of multiple myeloma (two patients), infection (one patient), unknown cause (one patient), and a possible thromboembolic event (one patient).

Conclusion: Thalidomide alone was effective in patients with newly diagnosed myeloma. The combination with dexamethasone induced a high frequency of response, rapid onset of remission, and low incidence of serious irreversible toxicity. These observations support further studies of this promising combination for patients with newly diagnosed multiple myeloma.
Randomized Phase III Trial of Fluorouracil Alone Versus Fluorouracil Plus Cisplatin Versus Uracil and Tegafur Plus Mitomycin in Patients With Unresectable, Advanced Gastric Cancer: The Japan Clinical Oncology Group Study (JCOG9205)
Authors: Ohtsu Atsushi , Shimada Yasuhiro , Shirao Kuniaki , Boku Narikazu , Hyodo Ichinosuke , Saito Hiroshi , Yamamichi Noboru , Miyata Yoshinori , Ikeda Nobumasa , Yamamoto Seiichiro , Fukuda Haruhiko , Yoshida Shigeaki
Published: December 2002

Purpose: To compare fluorouracil (FU) alone with FU plus cisplatin (FP) and with uracil and tegafur plus mitomycin (UFTM) for patients with advanced gastric cancer in a prospective, randomized, controlled trial.

Patients and Methods: A total of 280 patients with advanced gastric cancer were randomly allocated and analyzed for survival, response, and toxicity. The survival curves were compared between groups by log-rank test on an intent-to-treat basis.

Results: At the interim analysis, the UFTM arm showed a significantly inferior survival with higher incidences of hematologic toxic effects than did control arm FU alone, and the registration to UFTM was terminated. Both investigational regimens, FP and UFTM, had a significantly higher incidence of hematologic toxic effects than FU alone, although the effects were manageable. The overall response rates of the FU-alone, FP, and UFTM arms were 11%, 34%, and 9%, respectively. The median progression-free survival was 1.9 months with FU alone, 3.9 months with FP, and 2.4 months with UFTM, respectively. Although FP demonstrated a higher response rate (P < .001) and longer progression-free survival than did FU alone (P < .001), no differences in overall survival were observed between the arms. The median survival times and 1-year survival rates were 7.1 months and 28% with FU, 7.3 months and 29% with FP, and 6.0 months and 16% with UFTM, respectively.

Conclusion: Neither investigational regimen, FP nor UFTM, showed a survival advantage as compared with FU alone. FU alone will remain a reference arm in our future trial for advanced gastric cancer.
Atypical progeroid syndrome: An unknown helicase gene defect?
Authors: Ruijs M.W.G. , van Andel R.N.J. , Oshima J. , Madan K. , Nieuwint A.W.M. , Aalfs C.M.
Published: December 2002

We describe a boy with chromosomal breakage syndrome, who died of hepatocellular carcinoma at the age of 17 years. Other findings included growth retardation, bilateral cataracts, premature graying of hair and elevated levels of urinary hyaluronic acid. Intellectual functions were normal. Although some manifestations were suggestive of Werner syndrome, the diagnosis could not be confirmed by molecular investigations. Therefore, this patient probably represents a provisionally unique syndrome, perhaps due to a mutation in a related (helicase) gene. © 2002 Wiley‐Liss, Inc.
Lack of association between eNOS gene polymorphisms and ischemic heart disease in the Spanish population
Authors: Via Marc , López‐Alomar Antonio , Valveny Neus , González‐Pérez Emilio , Bao Meritxell , Esteban Esther , Pintó Xavier , Domingo Enric , Moral Pedro
Published: December 2002

Through the nitric oxide (NO) production in the vascular system, the endothelial nitric oxide synthase (eNOS or NOS3) is a key enzyme in blood pressure regulation and atherosclerosis control. Several previous studies have suggested an important role of eNOS as a genetic risk factor for cardiovascular diseases. In this context, a genetic association study was carried out between two eNOS polymorphisms (the ecNOS4a/b VNTR and the G894T substitution) in a sample of 101 nuclear families having one affected offspring of ischemic heart disease (IHD). Transmission disequilibrium test (TDT) revealed partial associations between the VNTR marker and IHD in patients with a type A behavior pattern (TABP) (P = 0.0325, RR = 3.67) and for the haplotype formed by variant b of the VNTR and the T mutation of the G894T substitution in the IHD‐affected subgroup having body mass index (BMI) lower than 25 (P = 0.0348, RR = 0.22). However, once multiple testing correction was applied, the associations became nonsignificant. A significant effect of the haplotype b‐G increasing high‐density lipoprotein cholesterol (HDL‐C) plasma levels was detected (P = 0.021 after Bonferroni correction). From a population point of view, frequencies found for G894T substitution in Spain were significantly different from other populations. © 2002 Wiley‐Liss, Inc.
X‐linked dominant chondrodysplasia punctata (CDPX2) caused by single gene mosaicism in a male
Authors: Aughton David J. , Kelley Richard I. , Metzenberg Aida , Pureza Vincent , Pauli Richard M.
Published: December 2002

X‐linked dominant chondrodysplasia punctata (CDPX2; Happle syndrome) is recognized almost exclusively in females, who display mosaic and asymmetric features, presumed to arise secondary to random X‐inactivation. CDPX2 results from mutation of an X‐linked gene coding for sterol‐Δ8‐Δ7 isomerase (emopamil binding protein). We describe a boy with clinical features of CDPX2 (including those presumed to arise usually secondary to functional mosaicism in females). Biochemical and molecular studies demonstrate that he is mosaic for a sterol‐Δ8‐Δ7 isomerase gene mutation. He is the first reported example of single gene mosaicism giving rise to CDPX2 in a male. © 2002 Wiley‐Liss, Inc.
A clinical perspective of cystic fibrosis and new genetic findings: Relationship of CFTR mutations to genotype–phenotype manifestations
Authors: Kulczycki Lucas L. , Kostuch Marzena , Bellanti Joseph A.
Published: December 2002

The present report describes several aspects of the relationship of mutations in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene to phenotype expression of the disease including several clinical vignettes from the authors' experience. The genotype‐phenotype relationships in CF are complex, and are affected by many factors, including pollution, smoking, bacterial infection, malnutrition, and certain therapeutic agents. The number of CFTR mutations is growing continuously and rapidly, and more than 1,000 mutations have been discovered so far. From a genetic point of view, the ΔF508 mutation is not only the most frequently encountered but also the most severe genetic lesion for homozygotes. The great clinical variability observed in patients with CF, particularly the severity of lung disease, involvement of the pancreas, and male infertility, are beginning to be better understood through the knowledge, although incomplete, of CFTR mutations and their phenotype expressions. This knowledge has had very significant research and clinical applications in all dimensions of the CF problem. It has not only contributed to the enhancement of better diagnosis and clinical management, but it also has opened new and unanticipated lines of investigation and research. © 2002 Wiley‐Liss, Inc.
Inhibition of glial cell proinflammatory activities by peroxisome proliferator‐activated receptor gamma agonist confers partial protection during antimyelin oligodendrocyte glycoprotein demyelination in vitro
Authors: Duvanel Cécile Besson , Honegger Paul , Pershadsingh Harrihar , Feinstein Douglas , Matthieu Jean‐Marie
Published: December 2002

Peroxisome proliferator‐activated receptor gamma (PPAR‐γ) is a member of the nuclear hormone superfamily originally characterized as a regulator of adipocyte differentiation and lipid metabolism. In addition, PPAR‐γ has important immunomodulatory functions. If the effect of PPAR‐γ's activation in T‐cell‐mediated demyelination has been recently demonstrated, nothing is known about the role of PPAR‐γ in antibody‐induced demyelination in the absence of T‐cell interactions and monocyte/macrophage activation. Therefore, we investigated PPAR‐γ's involvement by using an in vitro model of inflammatory demyelination in three‐dimensional aggregating rat brain cell cultures. We found that PPAR‐γ was not constitutively expressed in these cultures but was strongly up‐regulated following demyelination mediated by antibodies directed against myelin oligodendrocyte glycoprotein (MOG) in the presence of complement. Pioglitazone, a selective PPAR‐γ agonist, partially protected aggregates from anti‐MOG demyelination. Heat shock responses and the expression of the proinflammatory cytokine tumor necrosis factor‐α were diminished by pioglitazone treatment. Therefore, pioglitazone protection seems to be linked to an inhibition of glial cell proinflammatory activities following anti‐MOG induced demyelination. We show that PPAR‐γ agonists act not only on T cells but also on antibody‐mediated demyelination. This may represent a significant benefit in treating multiple sclerosis patients. © 2002 Wiley‐Liss, Inc.
Neural progenitor cells resist excitatory amino acid‐induced neurotoxicity
Authors: Hsieh Wen‐Ya , Hsieh Yi‐Lin , Liu Demeral David , Yang San‐Nan , Wu Jian‐Nan
Published: December 2002

The applications of neural progenitor cells in clinical therapy for neural degeneration, such as Parkinson's disease, Huntington's disease, and cerebral infarction, have long been explored widely. It had been suggested that these cells may block the apoptosis of ischemia‐induced neuronal damage and may themselves resist neurotoxic factors. In the present study, neural progenitor cells derived from the cortex of rodent embryos were cultured with the mitogenic agent epidermal growth factor. It was observed that these progenitor cells could self‐renew and differentiate into a number of types of neurons and glial cells. By using sodium nitroprusside, glutamate, and N‐methyl‐D‐aspartate, these neural progenitor cells were shown to have a higher resistance to neurotoxicity induced by these drugs compared with primary neuronal cells. However, the release of nitric oxide in response to glutamate by these neural progenitor cells was similar to the released by primary neuronal cells. Also, when the glutamate‐stimulated increase in intracellular free Ca2+ concentration was measured, stimulation of the glutamate receptors could not induce a significant influx of Ca2+ into these progenitor cells until they differentiated. Our results suggest that the resistance of neural progenitor cells to neurotoxicity may be partially due to a lack of response to glutamate. In addition, some progenitor‐generated neurotrophic factors may contribute to the resistance of these cells to nitric oxide‐induced neurotoxicity. © 2002 Wiley‐Liss, Inc.
Peroxynitrite generated in the rat spinal cord induces oxidation and nitration of proteins: Reduction by Mn (III) tetrakis (4‐benzoic acid) porphyrin
Authors: Bao Feng , DeWitt Douglas S. , Prough Donald S. , Liu Danxia
Published: December 2002

To determine whether peroxynitrite at the concentration and duration present after spinal cord injury induces protein oxidation and nitration in vivo, the peroxynitrite donor 3‐morpholinosydnonimine (SIN‐1) was administered into the gray matter of the rat spinal cord for 5 hr. The cords were removed at 6, 12, 24, and 48 hr after SIN‐1 exposure, immunohistochemically stained with antibodies to dinitrophenyl (DNP) and nitrotyrosine (Ntyr), markers of protein oxidation and nitration, respectively, and the immunostained neurons were counted. The percentages of DNP‐positive (P = 0.023–0.002) and Ntyr‐positive (P < 0.001 for all) neurons were significantly higher in the SIN‐1‐exposed groups than in the ACSF controls at each time, suggesting that peroxynitrite induced intracellular oxidation and nitration of proteins. The percentages of DNP‐ and Ntyr‐positive neurons were not significantly different over time in either SIN‐1‐ or ACSF‐exposed groups (P = 0.20–1.00). The percentage of DNP‐positive neurons was 7.6 ± 3% to 12 ± 4.2% at 6–24 hr, and it was 14 ± 2% to 19 ± 2% at 6–24 hr for Ntyr‐positive neurons after SIN‐1‐exposure, whereas both ranged over 2–3% in ACSF controls. Mn (III) tetrakis (4‐benzoic acid) porphyrin (MnTBAP, a broad‐spectrum scavenger of reactive species) significantly reduced the percentages of DNP‐ and Ntyr‐positive neurons (P = 0.04 and 0.002, respectively) compared to a SIN‐1‐exposed, untreated group at 24 hr after SIN‐1 exposure. There were no significant differences between MnTBAP‐treated and ACSF controls (P = 0.7 for DNP and 0.2 for Ntyr). These results further demonstrate peroxynitrite‐induced protein oxidation and nitration and the efficiency of MnTBAP in scavenging peroxynitrite. © 2002 Wiley‐Liss, Inc.
Selective changes in the neurofilament and microtubule cytoskeleton of NF‐H/LacZ mice
Authors: Riederer Irène M. , Robert Patrick , Porchet Raymonde , Eyer Joël , Riederer Beat M.
Published: December 2002

This study focused mainly on changes in the microtubule cytoskeleton in a transgenic mouse where β‐galactosidase fused to a truncated neurofilament subunit led to a decrease in neurofilament triplet protein expression and a loss in neurofilament assembly and abolished transport into neuronal processes in spinal cord and brain. Although all neurofilament subunits accumulated in neuronal cell bodies, our data suggest an increased solubility of all three subunits, rather than increased precipitation, and point to a perturbed filament assembly. In addition, reduced neurofilament phosphorylation may favor an increased filament degradation. The function of microtubules seemed largely unaffected, in that tubulin and microtubule‐associated proteins (MAP) expression and their distribution were largely unchanged in transgenic animals. MAP1A was the only MAP with a reduced signal in spinal cord tissue, and differences in immunostaining in various brain regions corroborate a relationship between MAP1A and neurofilaments. © 2002 Wiley‐Liss, Inc.
Reduced expression of p27kip1 and increased hepatocyte proliferation in p53‐deficient mice
Authors: Yang Chuanwei , Sun Mingzeng , Ilic Zoran , Friedrich Thomas D. , Sell Stewart
Published: December 2002

Livers from wild‐type and p53‐deficient mice were analyzed for the expression of cell‐cycle regulatory proteins in an attempt to determine the mechanism for the increased proliferation of liver cells in p53‐deficient mice associated with enhanced susceptibility to aflatoxin‐induced liver cancer. The most striking difference found was a significant reduction of the cyclin‐dependent kinase inhibitor p27kip1 in the livers of 3‐mo‐old p53−/− mice, whereas only small changes were found in the expression of cyclins, cyclin‐dependent kinases, and the inhibitors p21cip1 and p16ink4a. Relative to wild‐type liver, the amounts of p27kip1 mRNA were reduced at both 1 and 3 mo, whereas the levels of p27kip1 protein were decreased only at 3 mo. These results identify an uncharacterized link between the expression of p53 and p27kip1 that may involve both transcriptional and post‐transcriptional regulation and allow hepatocytes to continue to proliferate after 3 wk of age. We postulate that this increased proliferation leads to increased susceptibility to aflatoxin‐induced hepatocarcinogenesis. © 2002 Wiley‐Liss, Inc.
A non‐Darwinian role for mutagenesis in stem cell–derived cancers
Authors: Bergstein Ivan
Published: December 2002

It is clear that mutations cause cancer. The implicated mechanism is Darwinism. That is, a stochastic series of mutations is purported to effect the cellular variability upon which natural selection acts to yield increasingly cancer‐like intermediates leading ultimately to malignant clones. It is no wonder then that the neoplastic phenotype is considered “alien,” having evolved via random unrehearsed events. Neoplasia, however, has also been depicted as something less than foreign, bordering on familiar. This is because cancer shares proliferative and invasive qualities with the native developmental processes of embryogenesis and adult tissue renewal/repair. A question then arises: If key features of malignancy already naturally exist within well‐choreographed programs, why reinvent this phenotype via stochastic multistep schemes rather than reactivate it largely en bloc? Indeed, as will be shown, tissues do harbor a malignant potential capable of reactivation. Specifically, this capability is maintained by stem cells (having inherited such from embryonic precursors)—a phenotype controlled by a microenvironment favoring perpetual rearing by (quiescent) stem cells of proliferative progeny for orderly renewal over neoplasia. Accordingly, normally well‐sequestered stem cells, when amid carcinogen/mutagen‐induced disruption to local surroundings, produce progeny tending by default toward disorderliness (neoplasia) over renewal. Because such tumor‐causing mutations act non–cell autonomously, this cancerous state is potentially reversible but subsequent cell‐autonomous mutations can impair particular clonal progeny, already cancerous, from regressing. Thus, a scenario wherein mutations (1) de‐repress malignancy non–cell autonomously and then (2) slow its reversion cell autonomously, commonly misinterpreted as Darwinian, may constitute a non‐Darwinian mechanism for the genesis of cancers that are stem cell derived. © 2002 Wiley‐Liss, Inc.
Fire and Vegetation History from the Coastal Rain Forest of the Western Oregon Coast Range
Authors: Long Colin J. , Whitlock Cathy
Published: December 2002

High-resolution charcoal and pollen analyses were used to reconstruct a 4600-yr-long history of fire and vegetation near Taylor Lake in the wettest forests of coastal Oregon. Today, fires in these forests are rare because the season of ignition does not coincide with months of dry fuels. From ca. 4600 to 2700 cal yr B.P. fire episodes occurred at intervals of 140±30 yr while forest vegetation was dominated by disturbance-adapted taxa such as Alnus rubra. From ca. 2700 cal yr B.P. to the present, fire episodes have become less common, occurring at intervals of 240±30 yr, and fire-sensitive forest taxa, such as Tsuga heterophylla and Picea sitchensis, have become more prominent. Fire occurrence during the mid-Holocene was similar to that of the more xeric forests in the eastern Coast Range and suggests that summer drought was widespread. After ca. 2700 cal yr B.P., a decrease in fire episode frequency suggests that cooler conditions and possibly increased summer fog allowed the establishment of present-day Picea sitchensis forests within the watershed. These results provide evidence that fire has been an important disturbance agent in the Coast Range of Oregon, and variations in fire frequency and climate have led to the establishment of present-day forests.
Are the Benches at Mormon Point, Death Valley, California, USA, Scarps or Strandlines?
Authors: Knott Jeffrey R. , Tinsley John C. , Wells Stephen G.
Published: December 2002

The benches and risers at Mormon Point, Death Valley, USA, have long been interpreted as strandlines cut by still-stands of pluvial lakes correlative with oxygen isotope stage (OIS) 5e/6 (120,000–186,000 yr B.P.) and OIS-2 (10,000–35,000 yr B.P.). This study presents geologic mapping and geomorphic analyses (Gilbert's criteria, longitudinal profiles), which indicate that only the highest bench at Mormon Point (∼90 m above mean sea level (msl)) is a lake strandline. The other prominent benches on the north-descending slope immediately below this strandline are interpreted as fault scarps offsetting a lacustrine abrasion platform. The faults offsetting the abrasion platform most likely join downward into and slip sympathetically with the Mormon Point turtleback fault, implying late Quaternary slip on this low-angle normal fault. Our geomorphic reinterpretation implies that the OIS-5e/6 lake receded rapidly enough not to cut strandlines and was ∼90 m deep. Consistent with independent core studies of the salt pan, no evidence of OIS-2 lake strandlines was found at Mormon Point, which indicates that the maximum elevation of the OIS-2 lake surface was −30 m msl. Thus, as measured by pluvial lake depth, the OIS-2 effective precipitation was significantly less than during OIS-5e/6, a finding that is more consistent with other studies in the region. The changed geomorphic context indicates that previous surface exposure dates on fault scarps and benches at Mormon Point are uninterpretable with respect to lake history.
Saharan Dust Transport and High-Latitude Glacial Climatic Variability: The Alboran Sea Record
Authors: Moreno Ana , Cacho Isabel , Canals Miquel , Prins Maarten A. , Sánchez-Goñi María-Fernanda , Grimalt Joan O. , Weltje Gert Jan
Published: December 2002

Millennial to submillennial marine oscillations that are linked with the North Atlantic's Heinrich events and Dansgaard–Oeschger cycles have been reported recently from the Alboran Sea, revealing a close ocean-atmosphere coupling in the Mediterranean region. We present a high-resolution record of lithogenic fraction variability along IMAGES Core MD 95-2043 from the Alboran Sea that we use to infer fluctuations of fluvial and eolian inputs to the core site during periods of rapid climate change, between 28,000 and 48,000 cal yr B.P. Comparison with geochemical and pollen records from the same core enables end-member compositions to be determined and to document fluctuations of fluvial and eolian inputs on millennial and faster timescales. Our data document increases in northward Saharan dust transports during periods of strengthened atmospheric circulation in high northern latitudes. From this we derive two atmospheric scenarios which are linked with the intensity of meridional atmospheric pressure gradients in the North Atlantic region.
HmCRIP, a cysteine‐rich intestinal protein, is expressed by an identified regenerating nerve cell
Authors: Emes R.D. , Wang W.-Z. , Lanary K. , Blackshaw S.E.
Published: December 2002

A Hirudo medicinalis cDNA isolated from regenerating CNS tissue at 24 h post‐axotomy was identified as a leech homologue of the mammalian cysteine‐rich intestinal proteins (CRIPs) and named HmCRIP. HmCRIP is up‐regulated within 6 h of axotomy, peaking at 24 h. This is the first demonstration of a CRIP homologue in regenerating CNS and in a serotonergic neurone. In rodents CRIP is an important factor in the regulation of the inflammatory immune response through control of Th1/Th2 differentiation. The role of HmCRIP in the regeneration competent environment of the annelid central nervous system is discussed.
Functional role of N‐linked glycosylation on the rat melanin‐concentrating hormone receptor 1
Authors: Saito Yumiko , Tetsuka Mitsue , Yue Li , Kawamura Yuuki , Maruyama Kei
Published: December 2002

Melanin‐concentrating hormone (MCH) is known to act through two G‐protein‐coupled receptors MCHR1 and MCHR2. MCHR1 has three potential sites (Asn13, Asn16 and Asn23) for N‐linked glycosylation in its extracellular amino‐terminus which may modulate its reactivity. Site‐directed mutagenesis of the rat MCHR1 cDNA at single or multiple combinations of the three potential glycosylation sites was used to examine the role of the putative carbohydrate chains on receptor activity. It was found that all three potential N‐linked glycosylation sites in MCHR1 were glycosylated, and that N‐linked glycosylation of Asn23 was necessary for full activity. Furthermore, disruption of all three glycosylation sites impaired proper expression at the cell surface and receptor activity. These data outline the importance of the N‐linked glycosylation of the MCHR1.
Conversion of 48S translation preinitiation complexes into 80S initiation complexes as revealed by toeprinting
Authors: Dmitriev Sergey E. , Pisarev Andrey V. , Rubtsova Maria P. , Dunaevsky Yan E. , Shatsky Ivan N.
Published: December 2002

A method of analysis of translation initiation complexes by toeprinting has recently acquired a wide application to investigate molecular mechanisms of translation initiation in eukaryotes. So far, this very fruitful approach was used when researchers did not aim to discriminate between patterns of toeprints for 48S and 80S translation initiation complexes. Here, using cap‐dependent and internal ribosomal entry site (IRES)‐dependent mRNAs, we show that the toeprint patterns for 48S and 80S complexes are distinct whether the complexes are assembled in rabbit reticulocyte lysate or from fully purified individual components. This observation allowed us to demonstrate for the first time a delay in the conversion of the 48S complex into the 80S complex for β‐globin and encephalomyocarditis virus (EMCV) RNAs, and to assess the potential of some 80S antibiotics to block polypeptide elongation. Besides, additional selection of the authentic initiation codon among three consecutive AUGs that follow the EMCV IRES was revealed at steps subsequent to the location of the initiation codon by the 40S ribosomal subunit.
Severe hypoglycaemia in a patient with glycogen storage disease type III induced by infectious mononucleosis
Authors: Kimura T. , Ikeda H. , Kato M. , Ito A. , Okubo M. , Hayasaka K.
Published: December 2002

A 10‐month‐old girl with glycogen storage disease type III developed recurrent severe hypoglycaemia induced by infectious mononucleosis. Severe metabolic damage probably reflected a rapid breakdown of liver cells induced by the viral infection.
Irreversibility and Limiting Possibilities of Macrocontrolled Systems II: Microeconomics
Authors: Tsirlin A. M. , Kazakov V. , Kolinko N. A.
Published: December 2002

The methods of finite time thermodynamics are used to solve the maximal profit problem in irreversible microeconomic systems, similar to the problems of generalized exergy, which were solved in the first part of the paper. The condition of equilibrium in open microeconomic systems is obtained.
Immune Cognition and Vaccine Strategy: Pathogenic Challenge and Ecological Resilience
Authors: Wallace Rodrick
Published: December 2002

We continue to study the implications of IR Cohen's work on immune cognition for vaccine strategies when simple elicitation of sterilizing immunity fails, using a mathematical model derived from the large deviations programme of applied probability. Our work makes explicit the linkage between an individual's ‘immunocultural condensation’ and embedding social or historical structures and processes, in particular power relations between groups. We use methods adapted from the theory of ecosystem resilience to explore the consequences of the sudden ‘perturbation’ caused by infection, in the context of such embedding. The methodology opens pathways in the design of vaccine strategy which are closed by simplistic genetic or cross-sectional ‘inequality’ analyses that — in effect — either reify ‘race’ or deny the persisting burdens of racism.
Comorbid anxiety disorders in civilians seeking treatment for posttraumatic stress disorder
Authors: Zayfert Claudia , Becker Carolyn B. , Unger Danielle L. , Shearer Deirdre K.
Published: December 2002

Research indicates that posttraumatic stress disorder (PTSD) is associated with high rates of comorbid psychiatric diagnoses. Yet, it remains unknown whether PTSD is associated with greater comorbidity relative to patients with other anxiety disorders. This study examined prevalence of comorbid anxiety disorders with PTSD relative to other disorders among a treatment‐seeking population. Patients with PTSD (n = 83) evidenced greater overall comorbidity as compared to patients with other anxiety (n = 151) or Axis I (n = 73) disorders. Compared to patients with panic disorder, patients with PTSD were more likely to be diagnosed with depression and social phobia, but not other anxiety disorders. Extent of anxiety disorder comorbidity was not related to PTSD severity. These findings are discussed in terms of their relevance for treatment of PTSD.
Preventing traumatic stress: Public health approaches
Authors: Sorenson Susan B.
Published: December 2002

Population‐based approaches to the primary prevention of posttraumatic stress disorder (PTSD) focus on the prevention of the stressor itself. Policy decisions also consider ways to allocate resources to best reduce potential damage from traumatic stressors and to ameliorate any resulting harm. A balance between broad risk prevention approaches and narrower treatment and recovery strategies can redistribute the risk of exposure and lead to fewer cases. Understanding that PTSD and its costs affect not only individuals who seek care, but also many others whose lives overlap with these individuals as well as society as a whole, further informs and shapes prevention decisions.