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In the present study we identified a 180 kDa molecule (p180) in rat lymph nodes (LN) apparently reactive with silkworm derived recombinant L-selectin (LEC-IgG) in a Ca(2+)-dependent manner. Analysis of amino acid sequence revealed that p180 has a strong homology to the macrophage mannose receptor (MMR), which was corroborated by the observation that p180 reacted with polyclonal anti-alveolar MMR antibody and mannosyl-BSA-agarose. In agreement with this notion, the binding of p180 to the silkworm LEC-IgG was inhibited by alpha-methyl-D-mannoside. However, in sharp contrast to its reactivity against the silkworm LEC-IgG, p180 failed to bind LEC-IgG produced by COS-7 cells, suggesting that p180 reacted with the silkworm LEC-IgG through the recognition of oligomannose-type oligosaccharides expressed on the silkworm products and that the lectin activity of L-selectin was not involved in the interaction. These results, together with the immunohistochemical studies showing that p180 was absent from the majority of high endothelial venules (HEV) but present in medullary macrophages, led us to conclude that p180 obtained from LN lysates by the use of the silkworm LEC-IgG is not a physiological ligand for L-selectin, warning against the use of recombinant proteins expressed in the baculovirus/ silkworm expression system for the detection of carbohydrate ligands.

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder associated with the expansion of a (CAG)n array in the MJD1 gene. We analyzed the sizes of the (CAG)n array using DNA samples from 61 members of four Chinese MJD families and 18 Chinese normal control subjects and confirmed that the (CAG)n array in 15 MJD chromosomes was expanded to 72-86 repeat units. There were no subjects with (CAG)n array sizes intermediate between those of normal and MJD affected groups. Meanwhile, we found a significant negative correlation between the age of onset of symptoms and (CAG)n array size. The largest (CAG)n array of 86 repeat units was in the youngest patient, whose age of onset was 5 years. The intergenerational increase in number of CAG repeat units was associated with the clinical phenomenon of anticipation.

cDNAs for the bovine alpha 1A-, hamster alpha 1B- and rat alpha 1D-adrenoceptors (AR) were transfected into human embryonic kidney 293 (HEK293) cells by calcium phosphate precipitation and stably expressed at high levels. The inositol phosphates (InsPs) accumulation was measured by the method of 3H-inositol incorporation and column chromatography. Susceptibilities to the desensitization of alpha 1-AR subtypes-mediated InsPs accumulation were determined in HEK 293 cells stimulated sustainedly by norepinephrine (NE). The NE-induced InsPs accumulation showed progressive decrease by NE pretreatment with increasing time of preincubation and concentration of NE in the cells transfected with all the alpha 1-AR subtypes. However, susceptibilities to the desensitization were different among the three subtypes. The desensitization of alpha 1A-AR took place earliest and needed lowest concentration of NE. The desensitization of alpha 1D-AR appeared to be the latest and needed hightest concentration of NE, while alpha 1B-AR stood in between.

Oltipraz has been used clinically in many regions of the world as an antischistosomal agent and is an effective inhibitor of aflatoxin hepatocarcinogenesis in rats. This chemopreventive action of oltipraz results primarily from an altered balance in aflatoxin metabolic activation and detoxication. In 1995, a randomized, placebo-controlled, double-blind intervention was conducted in residents of Qidong, People's Republic of China, who are at high risk for exposure to aflatoxin and development of hepatocellular carcinoma. The major study objectives were to define a dose and schedule for oltipraz that would reduce levels of aflatoxin biomarkers in biofluids of the participants, and to further characterize dose-limiting side effects. Two hundred thirty-four healthy eligible individuals, including those infected with HBV, were randomized to receive either 125 mg oltipraz daily, 500 mg oltipraz weekly, or placebo. Blood and urine specimens were collected to monitor potential toxicities and evaluate biomarkers over the 8-week intervention and subsequent 8-week follow-up periods. Overall, compliance in the intervention was excellent; approximately 85% of the participants completed the study. Objective evaluation of adverse events was greatly facilitated by inclusion of a placebo arm in the study design. A syndrome involving numbness, tingling, and pain in the fingertips was the only event that occurred more frequently among the active groups (18 and 14% of the daily 125 mg and weekly 500 mg arms, respectively) compared to placebo (3%). These symptoms were reversible and could be relieved with non-steroidal antiinflammatory agents. A more complete understanding of the chemopreventive utility of oltipraz awaits completion of an assessment of the efficacy of oltipraz in modulating levels of aflatoxin biomarkers.

To study the effect of the angiotensin-converting enzyme (ACE) inhibitors perindopril (Per) and enalaprilat (Ena) on the reactivity of the endothelium in normal rats.Male rats were treated intragastrically with Per (2 mg.kg-1.d-1) or placebo (n = 18) for 6 wk. Aorta was isolated for experiment. Another set of isolated aortic rings with and without endothelium were incubated with Ena (0.1 mumol.L-1) for 30 min. Responses to acetylcholine, serotonin, phenylephrine, sodium nitroprusside (SN), and nitroglycerin (Nit) were observed.Endothelium-dependent relaxation to acetylcholine was augmented in aortic rings from rats treated with Per in comparison with control. The IC50 value (95% confidence limits) decreased from 3.8 (0.56-26.1) mumol.L-1 (control group) to 0.98 (0.28-3.41) mumol.L-1 (Per-treated group). The maximal relaxation was augmented from 62 +/- 9% to 78 +/- 10% (P0.01). However, the responses to the endothelium-independent vasodilators, SN and Nit, were similar. Serotonin- and phenylephrine-induced contractions were decreased, which were influenced by basal release of endothelium-derived relaxing factor (EDRF). EC50 values was 6.1 (2.6-14.4) nmol.L-1 vs 8.3 (3.6-18.8) nmol.L-1 in comparison with control group and Per-treated group. The maximal contraction was decreased from 2.42 +/- 0.29 g (control group) to 1.96 +/- 0.25 g (treated group) (P0.01). Similar results were found in incubation with Ena.Ena and Per enhanced the basic release of EDRF from vascular endothelium.

In a pH 6.30 buffer solution containing 0.001% Tween-80, ofloxacin (OFX) gives a sensitive polarographic wave at -1.46 V (vs SCE), which can be used for the determination of OFX down to 10(-8) mol.L-1. The linear range is from 1.39 x 10(-7) to 1.39 x 10(-5) mol.L-1. The proposed method was applied to determination of OFX in urine and serum samples with relative standard deviation less than 7.0%.

Our previous work showed that a lymphocyte proliferation suppressing factor could be found in the serum of restraint mice. In the present work, it was found that intracerebroventricular (icv) injection of IL-1 receptor antagonist (IL-1Ra) was found capable of suppressing the production of such a serum protein under restraint stress. Nearly complete suppression could be achieved by 5.0 micrograms IL-1Ra. Intracerebroventricular injection of IL-1 beta (1 pg), however, increased the generation of the supressive protein. Neither intraperitoneal (ip) injection of IL-1Ra or IL-1 beta had any effect on the generation of the protein. The fact that icv. injection of a very small dose of IL-1 beta (0.06 fmol) was effective on the generation of the supressive protein led us to suggest that IL-1 in brain might act as an important mediator between CNS and the immune system.

The role of tumor-specific T cells in mediating the regression of metastatic melanoma has been suggested by the clinical response of patients to treatment with tumor-infiltrating lymphocytes (TIL). A number of Ags recognized by class I-restricted melanoma-specific T cells have recently been isolated, raising the hope that this will lead to the development of improved therapies. In this study, we report the cloning of a tumor Ag recognized by T cells from melanoma patient 888. Previously, we reported that TIL 888, grown from the tumor of this patient, recognized tyrosinase in an HLA-A24-restricted fashion. This line, when infused into the autologous patient, resulted in complete regression of multiple metastases. Three years later, a second TIL line, TIL 1290, was isolated from a recurrent pelvic tumor. Infusion of a mixture of TIL 888 and TIL 1290 cell lines into the patient resulted in complete regression of a residual abdominal mass and the patient remains disease-free 2 yr later. The TIL 1290 cell line, which recognized melanoma in an HLA-A24-restricted manner, failed to recognize tyrosinase. TIL 1290 was then used to screen an 888 melanoma cDNA library, and an Ag was isolated that did not correspond to any found in sequence databases. This gene, termed p15, was found to be expressed in a variety of normal tissues, and a peptide epitope recognized by TIL 1290 was found to represent the product of an nonmutated gene. Screening of additional cDNA pools resulted in the isolation of a second clone which stimulated TIL 1290. This clone also appeared to represent a transcript of the p15 gene, indicating that this gene may encode the predominant Ag recognized by TIL 1290.

Our previous work showed that a suppressive factor (a protein with large molecular weight) in serum was induced by restraint stress in mice and rats, which suppressed Con A induced lymphocyte proliferation. It was also found that the generation of serum suppressive factor was under control of the central nervous system. Our further study showed that intracerebroventricular (icv) injection of interleukin 1 receptor antagonist (IL-1Ra) antagonised the generation of serum suppressive factor induced by restraint stress and icv injection of interleukin-1 beta (IL-1 beta) increased the generation of the suppressive factor. Our experiment also showed that the serum suppressive factor induced by restraint stress was first made in lymph tissue and then released into blood. The present work was designed to investigate the role of IL-1 in the brain in generation of the suppressive factor in lymph node in mice. Icv injection of IL-1 beta (1 pg/mouse) was shown to significantly increase the generation of the suppressive factor in lymph node. Icv injection of IL-1Ra, however, antagonised generation of the suppressive factor. In mice without restraint stress, both the suppressive factor in serum and in lymph node were found to be induced in dose-dependent manner by icv injection of IL-1 beta. Taken together, these results suggest that IL-1 beta in brain played a very important role in generation of the suppressive factor in lymph node. The positive correlation between the suppressive action of lymph node and of serum added to the evidence that lymph tissue is probably the source of the serum suppressive factor.

Both active and sterile sub-eV neutrinos can serve for hot dark matter (DM) in the Universe. We consider the beta-decaying (e.g., 3H) and EC-decaying (e.g., 163Ho) nuclei as the most promising targets to capture hot DM in the laboratory. We calculate the capture rates of relic electron neutrinos and antineutrinos against the corresponding beta decay or electron capture (EC) decay backgrounds in different flavor mixing schemes. We stress that such direct measurements of hot DM might not be hopeless in the long term.

Ninety two patients with unexplained syncope and 52 normal controls without history of syncope were divided into three groups respectively. Baseline tilt table test (BTTT), multistage isoproterenol tilt table test (MITTT), and single stage isoproterenol tilt table test (SITTT) were performed in all of them. Logistics regression was used with the result of TTT as independent variable; dependent variables included sex, age, basal heart rate, basal blood pressure, the index of syncope (i) and the difference between basal heart rate and the rate before tilting (h12). The results were as follows: (1) According to the regression for the total population tested, the main factors influencing the result of TTT were i and h12 (P = 0.012 and P = 0.001). Similar result was found in the patient group (P = 0.052 and P = 0.032). (2) In the control group, sex and h12 were the predictors of the result (P = 0.090 and P = 0.016). It is concluded that: (1) The result of TTT is mainly affected by the frequency and degree of syncope, as well as by the use of isoproterenol; (2) Isoproterenol increases the sensitivity of TTT, but decreases the specificity; (3) Sex is probably an important factor affecting the result of TTT.

Peritoneal mesothelioma is an infrequently encountered tumor that has a poor prognosis. Five female cases are reported in this article: one of epithelial type, one fibrous and three mixed, and there are two benign and three malignant cases. Abdominal mass, pain, ascites and weight loss are main manifestations. The epithelial and mixed types are prone to produce ascites. CT scanning is helpful for preoperation diagnosis. In 3 of the 5 patients the tumors have been thoroughly removed, one patient was treated with a partial removal, and one with biopsy only. Two patients have received chemotherapy after operation. The four patients who were given effective treatment survived each longer than 12 years, 55 months, 26 months and 15 months. One of the 5 patients who received biopsy only at laparotomy died two months later. It is recommended that if the primary tumor of the organs in the peritoneal cavity could be excluded, any patient with an abdominal mass and ascites should be given the benefit of doubt that it might be a case of peritoneal mesothelioma. Laparotomy should be carried out, and all the visible tumor masses should be resected as completely as possible. Cytoreductive surgery should be done in patients with recurrence. If postoperative chemotherapy or radiotherapy is given the prognosis may be improved.

Selective ablation of slow pathway by radiofrequency (RF) current in 34 patients with atrioventricular (AV) node pathways and tachycardia was performed with two methods in our section; posterior approach was used in the first 12 patients, the slow pathways were ablated successfully. Inferior approach was performed in the other 22 patients. Slow pathways were interrupted in 14 patients. Retrograde fast pathways and/or slow pathways were ablated in 6 patients. Retrograde fast pathways and slow pathways were abolished and antegrade fast pathways were injured transitorily in 2 cases. The total procedure time was shorter, RF applications were fewer by inferior approach than by posterior approach (P0.05). Both antegrade and retrograde conduction of fast pathways had not been affected after slow pathways were ablated (P0.05). After a mean of 8 months follow-up, two patients recurred and were ablated successfully again. We come to the conclusion that inferior approach might be a preferable method compared with posterior approach; the slow pathways is the compact node and its posterior input of transitional cells; the retrograde fast pathway may be the anterior superficial group of transitional cells and is not always in the same location of antegrade fast pathway.

By using French's method TBSA in CSFs of 43 patients with tuberculous meningitis and 40 patients with non-tuberculous meningitis were performed. All the patients with tuberculous meningitis were positive and all the patients with non-tuberculous meningitis were negative. So the results showed that the method is a rapid, sensitive and accurate for diagnosis of tuberculous meningitis.

The authors report extraction of cupric intraocular foreign bodies in 108 cases with a success rate of 99.07%. The methods utilized and improvements made in localizing the foreign bodies and the procedures of operation were described. Suggestions were also made concerning the timing of operation and the treatment of preoperative and postoperative complications.

Thirteen new 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-aroyl-thiocarbamoyl-1-piperazinyl)-3- quinoline carboxylic acids were prepared. Their structures were characterized by elemental analysis, IR, HNMR and MS spectra. Preliminary pharmacological tests indicated that some of compounds Ia-m possess strong inhibiting activity against Escherichia coli, Bacillus subtilis and Proteus at concentration of 100 micrograms/ml.

We have investigated the possibility of using single-walled carbon nanotubes (SWNTs) as the infrared energy conversion material based on the configuration of SWNT/Si heterojunction. The performance of solar cells based on SWNTs has been examined under illumination by the light with different wavelengths. Our experimental results confirm that SWNTs play a critical role in transforming the infrared light (1550 nm) into the electrical energy. The encapsulation of C60 fullerene inside SWNTs is found to significantly enhance the performance of solar cells through adjusting the Fermi level of SWNTs.

The transport properties of single-stranded DNA (ssDNA) wrapped single-walled carbon nanotubes (SWNTs) are studied from low to room temperature. Atomic force microscopy reveals a regularly patterned geometry of ssDNA molecules on the surface of SWNTs. Our measurements indicate that the semiconducting behavior of SWNTs is drastically changed after ssDNA modification, showing a clear charge-transfer process at room temperature. At low temperatures single-electron tunneling features are observed up to 80 K, demonstrating clearly that quantum dots in series are created in the SWNTs due to the ssDNA wrapping.

By hybrid and two-photon pumping covering a wide wavelength region of 685. 0-718. 0 nm in K2-K system , yellow stimulated deffuse-band radiation corresponding to the transition 2 fII, — a of molecular potassium was generated. The excitation and coffision energy-transfer mechanisms are discussed. Key words : StilnUL3ted diffuse-band radiation ;hybrid pumping ;two-photon pumping1. IntroductIonThe generation of stimulated diffuse-band radiation is an important topic for molecular physics and laser spectroscopy , as it might be utilized to obtain some valuable informations about the molecules and todevelop tunable lasers. UV and violet diffuse-band stimulated radiation in molecular sodium and blue one inmolecular lithium have been generated by pumping the atoms or the moieculei'. Yellow diffuse-bandspontaneous radiation in molecular potassium has been observed via one-photon pumping of molecular high-lying states or some other excitation processes9.This paper reports some new results about the generation of stimulated diffuse-band radiation (565. 0-580. 0 nm) in the potassium vapor via two-photon pumping of molecular high-lying states with either pumpwavelength within the region of 685. 0-718. 0 nm and via hybrid excitation of the molecule-atom systemwith some certain wavelengths. The interesting excitation and collision energy- transfer processes are

To determine the possibility that asymptomatic bronchial hyperresponsiveness (BHR) develops into symptomatic asthma, a two-year follow-up study was conducted in 81 students (48 male, 33 female; 11 to 17 years) who were found to have BHR in a 3,067 population survey (BHR group). Eighty-eight age-matched students (48 male, 40 female) with normal bronchial responsiveness served as control subjects. Daily symptom cards were recorded. Peak expiratory flow rate was measured for 24 h when symptoms occurred. Histamine inhalation tests were performed at the beginning of the study and at the end of the first and the second year. In the BHR group, 58 students remained bronchial hyperresponsive at the end of follow-up. Nine of 31 students with initially diagnosed bronchial asthma had their symptoms relieved entirely, but ten asymptomatic students developed asthma. The incidence of newly diagnosed asthma (12.5 percent in the BHR group or 20 percent in the asymptomatic BHR group) and the total percentage of diagnosed asthma (39.5 percent) in the BHR group were significantly higher than those (2.27 percent, 2.27 percent) in the control group. FVC and FEV1 showed no significant difference between two groups. PD20 FEV1 values in newly diagnosed asthmatics were significantly lower than those in asymptomatic students both at the beginning (3.05 +/- 1.56 mumol vs 6.14 +/- 1.60 mumol, p0.05) or the end (3.47 +/- 1.73 mumol vs 6.55 +/- 1.51 mumol, p0.05). The percentage of early respiratory illness was significantly higher in those with newly diagnosed asthma (80 percent) than in asymptomatic students (22.3 percent), but atopic index and the percentage of parental asthma showed no difference between two groups. In nine asthmatics whose symptoms were relieved entirely in the two-year follow-up, PD20 FEV1 was undetectable within the cumulative dose of 7.8 mumol of histamine in three students and rose from 4.58 +/- 1.85 mumol to 7.62 +/- 1.02 mumol in the remaining six. The higher the BHR, the more likely the students developed asthma. About 45 percent of asymptomatic students with PD20or = 3.2 mumol developed asthma in the following two years and 80 percent of them had a history of early respiratory illness, suggesting that they may have subclinical or potential asthma.

Kidney and pancreas tissues from congenitally infected Ma ducks with duck hepatitis B virus (DHBV) were examined by immunohistochemical staining technique and electron microscopy. The immunostaining showed that DHBV antigen was localized in the cytoplasm of tubular epithelial cells of kidney and acinar cells of pancreas of infected ducks. Under electron microscope, we found that complete and incomplete DHBV particles existed in the dilated cisternae of rough endoplasmic reticulum of both the cells. The size of complete and incomplete virus particles was nearly uniform in both the cells, 50-65 nm and 40-50 nm in diameter respectively. Therefore, extrahepatic infection and replication of DHBV were directly demonstrated ultrastructurally.

Cr‐, Mo‐, or W‐substituted TlSrCaCuO and TlSrCuO samples were prepared and investigated by resistance and ac susceptibility measurements and by x‐ray diffraction analyses. The results showed that CrTlSrCaCuO, MoTlSrCaCuO, and WTlSrCaCuO systems form a 1212‐type phase, but with different Tc: 100K, 70 K, and 50 K, respectively. Some MoTlSrCaCuO samples exhibit weak superconductivity at 100 K. The Ca‐free CrTlSrCuO system is superconducting at 40 K and 77 K. The 40 K superconducting phase is a 1201‐type phase (Tl, Cr)Sr2CuO5, whereas the 77 K phase may be anew phase and remains to be identified.

The TlBaCaCuO system forms two series of superconducting compounds, double TlO‐layer Tl2Ba2Can−1CunO2n+4 and single TlO‐layer TlBa2Can−1CunO2n+3. The member of n=2 in the series with single TlO layer, TlBa2CaCu2O7, has been often called 1212 phase. The 1212 structure can be widely subjected to elemental substitutions, forming a large family of 1212‐type superconductors with a general formula of M1M22M3Cu2O7, where M1, M2, and M3 are metallic elements. In this paper, the existing 1212 phases are reviewed; formation and superconductivity of the 1212 phases are discussed in terms of the concept of mixed Cu valence; possible new 1212‐type phases are predicted; some experimental results for the predicted 1212 phases are presented.

Two cDNA clones have been isolated from a lambda g11 cDNA library constructed with poly(A)+ mRNAs prepared from spinach seedlings. These nuclear cDNAs encode chloroplast (cp) ribosomal (r) proteins designated L24 and L40. These r-proteins have been identified in the cp 50S r-subunit by immunoblot analysis, amino acid (aa) composition and N-terminal aa sequencing. The L24 r-protein contains a central eubacterial homologous core with the N- and C-terminal polypeptide extensions. The L40 r-protein has no homologous counterpart in bacterial ribosomes. The two nuclear encoded r-proteins have their homologues in pea, a legume, showing that specific elements of cp ribosomes are conserved in higher plants. Surprisingly, the cp-specific r-protein L40 has a higher aa substitution rate than that of other eubacterial-like cp r-proteins identified previously in pea and spinach.

The transport properties of field-effect transistors based on C60 fullerene peapods have been investigated and our findings indicate that the transport characteristics of single-walled carbon nanotubes (SWNTs) are highly sensitive to the encapsulated fullerenes due to the charge-transfer effect. Under light illumination, the photoinduced electron transfer characteristics are found in C60 peapods, which is different from those observed for empty SWNTs. The response characteristic of peapod devices to light is reflected in a shift of threshold voltage toward negative values, indicating an electron-doping process. After removing light the photoresponse is fully recoverable, indicating complete restoration of transferred electrons.

Liver specimens from the Shanghai Ma ducks congenitally infected with duck hepatitis B virus (DHBV) were examined by immunohistochemical technique and electron microscopy. All the 12 serum DHBV positive ducks showed varying degrees of positive straining in hepatocytes. In 8 of the 12 ducks, DHBV antigen was discovered in the cytoplasm of biliary epithelial cells. Conventional electron microscopy revealed two kinds of virus particles in the biliary epithelial cells: 1. the incomplete virus, 40-50 nm in diameter and spherical in shape with an outer membrane, located mainly in the dilated cisternae of rough endoplasmic reticulum of the cells in large amounts; 2. the complete virions, 55-60 nm in diameter, were spherical with an outer membrane and located mainly in the cytoplasmic vesicles in small amount. We believe the particles found in the biliary epithelial cells in this study were DHBV particles. It is most likely that the infection and replication of DHBV not only take place in the liver cells but also in the biliary epithelial cells.

5582 Purpose: To evaluate the clinical activity of oral Letrozole in patients with recurrent and advanced low malignant potential or low grade serous ovarian tumors and to determine the impact of steroid receptor expression on this observed activity. Methods: In a phase II design, we recruited patients with confirmed recurrent advanced stage low malignant potential tumors and recurrent low-grade serous carcinomas. Measurable disease was required. Steroid hormone expression (ER and PR), EGFR, and Her2/neu expression were determined on available pathological material by IHC from the initial surgery or at documentation of recurrent disease and blood was obtained before enrollment and every other month while on therapy. Letrozole was administered orally at a dose of 2.5 mg once a day. The endpoints were objective response rate assessed by Response Evaluation Criteria in Solid Tumor. Adverse events were graded using the National Cancer Institute Common Toxicity Criteria. Results: Thirteen patients meeting eligibility have been enrolled are evaluable for response and toxicity. From objective clinical parameters (RECIST) no patients had a CR or PR; five patients (38%) had disease stabilizations, eight patients had progressive disease. However, using criteria for CA 125 response, we obtained a complete serologic response in 2 of 13 patients (15%), and a partial serologic response in 2 additional patients (15%); marker stabilization was seen in 5 other patients (38%). CA125 increased in four patients (31%). We also detected the presence of ER, PR, EGFR, Her-2/Neu by IHC, and estradiol in the plasma by ELISA. No significant correlation was observed between tumor marker response and ER expression alone. However, when we evaluated the co-expression of ER/PR we found 3 of 5 (60%) patients had a serologic response compared to just 1 of 8 patients with ER+/PR- tumors (P=0.07). We observed no severe adverse events. Conclusion: Our preliminary data suggests that oral Letrozole has some antitumor activity in recurrent advanced low grade or borderline ovarian tumors and is well tolerated. The analysis of correlation between objective response and combined prediction markers including phosphorylated ER, PR, AKT, and IGFR is ongoing (Supported by CTRF). No significant financial relationships to disclose.

The synthesis of Cs-encapsulated single-walled carbon nanotubes (Cs@SWNTs) and double-walled carbon nanotubes (Cs@DWNTs) is realized by a plasma ion-irradiation method. Transmission electron microscopy observations confirm that chainlike and amorphous Cs fill SWNTs and DWNTs, respectively. The electronic transport properties of Cs@SWNTs and Cs@DWNTs are experimentally investigated at both room and low temperatures by fabricating them as the channels of field-effect transistor devices. Our results reveal that both Cs@SWNTs and Cs@DWNTs exhibit n-type semiconducting behavior at room temperature. The electronic properties of the Cs-encapsulated nanotubes can be controlled by adjusting the Cs filling levels during the plasma ion irritation process. At low temperatures, Coulomb blockade transport characteristics are observed for both encapsulated nanotubes, and the size of quantum dots formed in Cs@DWNTs is much smaller than that formed in Cs@SWNTs. More importantly, the n-type characteristics of Cs@SWNTs and ...

The authors report electric transport properties of resonance tunneling field-effect transistors fabricated using C60-filled metallic double-walled carbon nanotubes. The devices exhibit strong resonance tunneling characteristics and the distinct negative differential resistance with high peak-to-valley current ratio about 1300 is observed at room temperature. In particular, at high bias voltages, the tunneling current is completely dominated by the Coulomb oscillation peaks with uniform conductance at room temperature, reflecting a strong single-electron tunneling effect.

A radial basis-function network (RBFN) is proposed for the intelligent control of a wind-turbine emulator and an induction-generator (IG) system with an AC/DC power converter. First, the indirect field-oriented mechanism is designed for the control of the IG system. Since the IG system is a nonlinear and time-varying dynamic system, an on-line trained RBFN is developed for the tracking controller of DC-link power to improve the control performance. The rotor speed of the IG, the DC-link voltage and current of the power converter are detected simultaneously to yield maximum power output of the converter through DC-link power control. Then, a closed-loop wind-turbine emulator, also using the RBFN, is designed to produce the maximum power for the IG system at various wind speeds to confront the parameter dependency of the wind-turbine emulator. Further, some experimental results are provided to show the effectiveness of the proposed wind-turbine emulator and IG system using the RBFN controller. Finally, the control performance of the DC-link voltage control using the RBFN is also discussed.

The transport eddy-current loss of a nearly nonmagnetostrictive CoFeSiB amorphous wire under a large longitudinal bias field can be several times greater than the value commonly expected by the classical model. Related to the overlarge circular susceptibility under the same condition, this is attributed to the formation of disklike soft-magnetic microstructures around hard magnetic inclusions randomly embedded in a soft magnetic matrix.

The circular magnetization process of FeSiBCuNb amorphous and nanocrystalline wires has been followed by the impedance measurements as a function of the amplitude and the frequency of driving current. The domain structure and consequently, the magnetization process have been tailored by suitable thermal processing. The different circular coercivity mechanisms are deduced by analyzing the magnetic losses. We find that the coercivity is due to domain-wall pinning for wire with axial domain, while the coercivity is from domain nucleation for one with transverse domain structure. In addition, the influence of axially applied field H is different for wires with different domain structure. The application of tensile stress to a wire with positive magnetostriction can be taken as an axial induced anisotropy, which makes the circular permeability decrease and the coercivity increase. Finally, the influence of driving current frequency on the circular magnetization process has been also studied for the wire with transverse domain structure. The results indicate that the frequency effect is from the eddy-current damping.

The magnetoimpedance (MI) effect has been investigateded in Fe63.5Cr10Si13.5B9Cu1Nb3 alloy wire exhibiting an ultrasoft magnetic character after suitable thermal treatment at 525 °C. It has been measured as a function of the sample length and of the distance to the ends of the wire (MI profile). The observed dependence on both parameters is correlated with the local particularities of the magnetization process: complex domain structures emerging near the ends to decrease the magnetostatic energy modify the local magnetic susceptibility and consequently the MI response. The present study points out the importance of geometrical dimensions of samples and measuring conditions when reporting numerical values in MI studies. This wire, showing large magnetoimpedance together with optimized soft magnetic behavior and improved corrosion properties seems to be indicated as a sensing element in GMI based sensors.

dc, ac field cool, and their various combinations were applied to standard top and bottom spin valves. While dc field cool from the above blocking temperatures helps to align the antiferromagnetic (AFM) spins, therefore introducing exchange bias, ac field cool statistically randomizes the AFM spins, thus effectively erasing it. The various combinations of these two processes help to separate the contribution to the total exchange bias from different AFM grain sizes. It is found that, compared to the smaller grains, the local exchange bias for larger AFM grains is smaller, but with better temperature stability. More detailed analysis of the temperature dependence of the exchange bias reveals that it is influenced not only by the exchange coupling between FM and AFM layers, but also the interaction among different AFM grains. Such interactions include the direct antiferromagnetic interactions among AFM grains, and the indirect ferromagnetic interaction through the adjacent FM layer. The net interaction is t...

Mono-γ and polycrystalline specimens of an AISI stainless steel were cycled in a 1N H2SO4 solution under different potentials. The correspondence between strain wave form and transient current curve has been studied. Transient current, which has been measured with out-of-the-ordinary resolution, has been demonstrated to have two components: the current associated with plastic strain (CAPS) and the current associated with elastic strain (CAES), caused exclusively by plastic deformation and elastic deformation respectively. The strong interaction between the environment and the fresh area at slip steps is the main cause of the CAPS. The wave forms of the CAPS is affected by selective dissolution of iron, tension-compression asymmetry, and the fatigue cracking process. The CAES is produced by the variation in the energetic status of the surface, and possibly by the charging effect of the electric double layer.

Nominal TlSr2(Er1-y Sr y )Cu2O x samples were prepared, and were investigated by powder X-ray diffraction analyses, and by resistivity and thermoelectric-power measurements. The samples with y=0.0-0.5 are nearly pure 1212-type phase TlSr2(Er1-y Sr y )Cu2O7-δ. The 1212 phase converts from semiconducting to superconducting at y=0.1-0.2, and exhibits the optimal superconducting behavior when y=0.4-0.5. In the range of 150-300 K, the thermopower values of the 1212 phase are nearly temperature-independent. The hole concentration calculated from the thermopower data using the Hubbard model in high temperature limit with strong on-site Coulomb interaction is quantitatively consistent with the y/2 value.