Search

Small cell lung cancer is more responsive to chemotherapy and radiotherapy than are other forms of lung cancer. Nevertheless, most patients still relapse, and cures are rare. After failure of initial therapy, death comes rapidly, occurring within seven to eight weeks following relapse. An attempt was made to evaluate the use of high-dose etoposide with cisplatin for the treatment of small cell lung cancer in 20 patients who had relapsed after initial treatment. Two patients died from infections following treatment. Of the remaining 18 patients, half achieved responses. The average survival time was 20.3 weeks, indicating a synergistic effect between the high-dose etoposide and cisplatin. The study also experimentally treated five patients with recombinant granulocyte colony-stimulating factor in an effort to reduce the period of white blood cell suppression which follows the chemotherapy. (It is during this period that potentially fatal infections are most likely to occur.) There was no evidence that the exogenous colony-stimulating factor reduced the white blood cell recovery time in these patients. (Consumer Summary produced by Reliance Medical Information, Inc.)

Small cell lung cancer (SCLC) grows rapidly and has a high propensity for spreading quickly and widely. Although SCLC is sensitive to both radiation and chemotherapy, most patients suffer relapses within a year or two, probably due to the emergence of subpopulations of cancer cells resistant to chemotherapy. Since some anecdotal evidence suggested that doxorubicin played a role in the health of the few patients who survived SCLC more than five years, a retrospective study was completed of 159 patients with SCLC. Ten patients survived for five years or more; this indicates a five-year survival rate of 6.3 percent, and a cure rate comparable to other published reports. The nine patients who could be evaluated had a complete response to initial chemotherapy. Statistical analysis of the data did not reveal a significant role for radiotherapy. In the patients studied, age and sex did not appreciably affect survival. These results are not in agreement with some other published data. Chemotherapeutic regimens containing doxorubicin were, however, significantly correlated with improved chances of survival. These results indicate that doxorubicin is an indispensable part of combination anticancer therapy for small cell lung cancer. (Consumer Summary produced by Reliance Medical Information, Inc.)

We have studied the microstructure of melt-growth GdBa2Cu3O7??(Gd123) bulk superconductors with the addition of Gd2Ba4CuMOx(abbreviated as M2411 with M = Mo or Zr) particles by transmission electron microscopy. Gd123 bulks are prepared with nominal compositions Gd123+(0.4?x) Gd211+xM2411+0.1 BaO2in a molar ratio with x= 0-0.2. The addition of M2411 particles induced nanosized particles inside bulks. They are apparently distributed well under seeding positions, where fewer Gd211 particles are located. The observed nanosized particles assigned as M2411 may play the role of flux pinning centres, leading to an enhanced Jc. However, the addition of M2411 with x>0.12 leads to the appearance of excess liquid and macrodefects in the bulks. Enhanced interfacial stress induced by the excess M2411 addition was found, together with modified local chemical compositions. These results account for both the suppression of the superconducting properties and the formation of the band structure in the present system.

We used Ba-Cu-O substrates to fabricate bulk Nd-Ba-Cu-O superconductors using a top-seeded melt-growth method. There were several advantages for the use of Ba-Cu-O substrate compared to conventional substrate materials such as MgO, ZrO2, Al2O3, RE123 and RE211 (RE =  rare earth). The Ba-Cu-O did not react with the precursor and minimized liquid loss. Accordingly, the introduction of large-sized cracks was suppressed. We also found that Tcvalues were high at the bottom regions, which was ascribed to the beneficial effect of Ba-Cu-O in suppressing Nd/Ba substitution. As a result, we obtained bulk Nd-Ba-Cu-O superconductors that exhibited fairly good field-trapping capabilities, even at the bottom surfaces.

We measured the contact resistance of a silver block with convex curvature and silver, a melt-textured Y-Ba-Cu-O sample (YBCO), and a silver-deposited YBCO sample (dAg/YBCO) to clarify the main source of the resistance. The study was performed with the development of a persistent current switch in mind. The contact resistance was largest in the Ag/YBCO contact. It decreased by increasing the thickness of the deposited-Ag layer for the Ag/dAg/YBCO contact. However, the smallest resistance of the Ag/dAg/YBCO contact was even larger than that of the Ag/Ag contact. This is probably due to the fact that the Ag/dAg/YBCO contact has two interfaces. The present result suggests that the contact area is dominant in controlling the contact resistance. A simulation study of the contact area with a finite element method (FEM) also supported this idea.

Pulsed field magnetization (PFM) is a practical method for magnetizing bulk superconductors, but the amount of trapped magnetic flux is usually smaller than that magnetized by the field cooling (FC) method due to the heat generation by the flux motion during pulsed field application. In this study, we magnetized a Y-Ba-Cu-O bulk superconductor grown from a seed which was placed at deviating positions from the centre of the bulk to investigate the effect of inhomogeneous penetration of the flux into the bulk superconductor during the PFM. The maximum trapped field by the PFM was almost the same value as by the FC method. This suggests that the inhomogeneity of the bulk superconductor affects the trapped field on the PFM. The magnetic flux can penetrate into the centre of the bulk even if the applied field is small, which contributes to reducing the extra heat generation due to the flux motion.

Gd₂Ba₄CuMoO_y (Gd2411) single phase was synthesized in air and added into GdBa₂Cu₃O_7−δ (Gd123) bulk superconductors with the addition amount ranging from 0.2% to 20%, in molar ratio to Gd123. Both microstructure and superconducting properties of each bulk were investigated from the seed position to the boundary of a single domain. Although a band structure with the alternative distribution of Gd₂BaCuO₅ (Gd211) and Gd2411 appeared in all samples, the range of this inhomogeneity only appeared within 5 mm from each side of the seed. The critical current density (J_c) shows that Gd2411 plays an important role in the control of the local superconducting properties. The highest J_c reached 84 500 A cm⁻² at 77 K under the self-field in the sample with 0.4% addition of Gd2411.

Gd2Ba4CuMoOy(Gd2411) single phase was synthesized in air and added into GdBa2Cu3O7??(Gd123) bulk superconductors with the addition amount ranging from 0.2% to 20%, in molar ratio to Gd123. Both microstructure and superconducting properties of each bulk were investigated from the seed position to the boundary of a single domain. Although a band structure with the alternative distribution of Gd2BaCuO5(Gd211) and Gd2411 appeared in all samples, the range of this inhomogeneity only appeared within 5 mm from each side of the seed. The critical current density (Jc) shows that Gd2411 plays an important role in the control of the local superconducting properties. The highest Jcreached 84?500 A cm?2at 77 K under the self-field in the sample with 0.4% addition of Gd2411.

Single-domain GdBa₂Cu₃O_7−δ (Gd123) bulk superconductors were fabricated in air and studied with different BaO₂ contents and Gd₂BaCuO_7−δ (Gd211) initial particle sizes. The experiments showed that BaO₂ addition effectively suppressed the Gd/Ba substitution and therefore enhanced superconducting properties such as J_c and B_irr. An optimum addition amount is Gd123:BaO₂ = 1:0.1 molar. By employing fine Gd211, J_c at low magnetic fields is further enhanced. At B = 0 and 77 K, J_c reached 86 000 A cm⁻², which is a record high J_c value for melt-processed Gd123 bulk samples in air.

Single-domain GdBa2Cu3O7??(Gd123) bulk superconductors were fabricated in air and studied with different BaO2contents and Gd2BaCuO7??(Gd211) initial particle sizes. The experiments showed that BaO2addition effectively suppressed the Gd/Ba substitution and therefore enhanced superconducting properties such as Jcand Birr. An optimum addition amount is Gd123:BaO2= 1:0.1 molar. By employing fine Gd211, Jcat low magnetic fields is further enhanced. At B= 0 and 77 K, Jcreached 86?000 A cm?2, which is a record high Jcvalue for melt-processed Gd123 bulk samples in air.

We have studied the microstructures of subgrains in large single-domain RE–Ba–Cu–O bulk superconductors and their effects on superconducting properties. Subgrains with high misorientation angles were seen at the positions of the later stage of melt growth, or the positions where the second-phase particles are large in size and volume. An electron backscattering diffraction technique revealed that the orientation of the second-phase particles affects the orientation of the matrix phase, some of which forms the subgrain boundaries. Electric and magnetic measurements have been performed for several samples having different subgrain geometries and the results of I–V and resistivity measurements indicated that subgrains act as weak links, especially in a high magnetic field region.

We have studied mechanical properties of melt-processed single-grain Sm-Ba-Cu-O (Sml23+Sm211) bulks with and without silver doping. Tensile stress is induced by thermal stress during heat treatment, and also induced by applying magnetic fields. It is found that the silver addition was effective in decreasing the thermal stress and increasing the tensile strength of the Sm-Ba-Cu-O bulk. The tensile strength of the silver doped sample was 37.4MPa, which is about one and half times larger than that of the undoped sample.

The influence of KclO3addition on the AC complex susceptibility (χac) and microstructural morphology of YBCO HTSC with nominal composition Y(1−0.2x)Ba(2−0.2x)KxCu3Oy(x = 0 ÷ 0.40) were investigated. Xac was recorded as a function of temperature and of the concentration of KClO3in various AC magnetic fields up to 19 Oe. The data were analyzed using the relation h = a(1 − Tm/Tc)n. The results obtained showed that the presence of K- and Cl-containing impurities on the grain boundaries change the intergranular coupling and, within certain concentration limits, improves the superconducting parameters.

We evaluated the sensitivity of CT for detecting mediastinal lymph node metastases in patients with nonsmall cell bronchogenic carcinoma. Computed tomography of 208 cases of surgically proven bronchogenic carcinoma from three institutes was evaluated retrospectively using specific diagnostic criteria. These consisted of two size thresholds for specific mediastinal node regions: 13 mm short transverse diameter for nodes in the subcarinal, precarinal, and tracheobronchial regions and 10 mm for other regions. Based on these criteria, the overall sensitivity of CT was 69, specificity 94, and accuracy 86 for detection of metastasis. In cases of adenocarcinoma, sensitivity was 61, specificity 93, and accuracy 81, and in those of squamous cell carcinoma the respective values were 86, 94, and 92. Comparison between the results using the present criteria with the former criterion of 10 mm short transverse diameter for all mediastinal nodes revealed that the number of false-positive cases decreased markedly. We conclude that more accurate CT evaluation of mediastinal lymph node metastasis in nonsmall cell bronchogenic carcinoma can be achieved with specific size criteria for specific mediastinal regions.

A new type of bending actuator, "monomorph", is proposed by using a single plate of semiconductive piezoelectric ceramics. The principle of bending originates from the nonuniform distribution of the electric field in a single plate caused by the semiconductor-metal electrode contact. Monomorph characteristics are exemplified in lead zirconate based and barium titanate ceramics. A bend curvature comparable to that of conventional piezoelectric "bimorphs" can be obtained.

The effects of various oxygen partial pressures (PO2) during melt processing on the superconducting properties of fabricated NdBa2Cu3Oy(Nd123) superconductors have been systematically investigated. Unlike in air or O2, samples melt-processed in reduced oxygen atmospheres exhibited unprecedentedly high Tc's of 95-96 K with a sharp superconducting transition. Especially, for a sample melt-processed in 0.1% O2in Ar, the magnetization hysteresis (M-H ) loop was kept open up to 7 T at 77 K and for the field parallel to the c-axis of the sample (H//c), implying that very effective flux pinning can be achieved in high magnetic fields.

REBa2Cu3Oysuperconductors with rare earth (RE) ions with large radii (RE: La, Nd, Sm) exhibit relatively low Tcdue to the presence of RE-Ba solid solution. We have found that this solid solution can be suppressed if these superconductors are melt processed in a reduced oxygen atmosphere. We have also found that critical current densities of these superconductors are higher than those of melt processed YBa2Cu3Oywith fine Y2BaCuO5inclusions in a high field region. The irreversibility line was also shifted toward the higher H-Tregion. We believe that flux pinning in these superconductors is ascribable to a finely distributed RE(Ba1-x, REx)2Cu3Oyphase in a good superconductive matrix.