Sub-boundaries in3He and4He single crystal and their migration below 1K observed by X-ray topography

The observation of alterations in crystal structure at ultra-low temperatures by X-ray diffraction, made possible by the realization of synchrotron radiation use after a quarter of this century, plays an important role in obtaining an understanding of the base structure of solids. For that, two types of³He-⁴He dilution refrigerators with a modified version of the top-loading facilities were installed at the BL-3C₂ and 6C₁ stations of the Photon Factory. In BL-3C₂, the behaviors of lattice defects in solid helium have been studied by X-ray topography. In this note, the migrations of sub-boundaries in³He and⁴He single-crystals are reported as being the result of an annealing effect. After annealing hcp⁴He single crystals for 80min at 0.5K, no change in crystallographic orientations could be easily observed from white SR X-ray topographs. In the same type topographs of bcc³He single crystals after annealing for several hours at 03K, migration of sub-boundaries were conspicuously discerned.     

Preparation and magnetic properties of Ti1−xVxPO4

The solid solutions of Ti_1?xV_xPO₄ were prepared under the reductive circumstance, although there seems to be immiscibility near x=0.5. Their magnetic susceptibility was analysed by the temperature-independent and Curie-Weiss contribution. The temperature-independent contribution increased gradually with x until x=0.4 and then decreased to 0 at x=1.0. A bent was observed at x=0.5 in the curve for the Curie constant against x and at x>0.5 the Curie temperature became strongly negative with x.In the region of x≦0.4, the Curie constant corresponded to the electronic configuration of d¹ for a vanadium ion. On the other hand, the Curie constant reflected the d² configuration for a vanadium ion in the range of $\text{x}\text{≧0.6}$. This fact indicates that Ti³⁺/1bV³⁺ homopolar bonds are formed in accordance with the replacement of Ti³⁺ with V³⁺ at x≦0.4. Vanadium ions added further, which substitute for Ti³⁺ in Ti³⁺/1bV³⁺ pairs, do not form the homopolar bond with V³⁺ ions and both V³⁺ ions contribute magnetically as ions with d² configuration.     

Sequential cis/trans autophosphorylation in TrkB tyrosine kinase

TrkB, a member of the tyrosine kinase family of growth factor receptors, is activated by binding of brain-derived neurotrophic factor or neurotrophin 4/5. The intracellular kinase domain of TrkB (ICD-TrkB) was prepared by an insect cell expression system and characterized to identify the mechanism of autophosphorylation. The time course of autophosphorylation, which shows a biphasic progression with a slow nonlinear phase followed by a fast linear phase, indicates the existence of autophosphorylation-induced activation in ICD-TrkB. This is also supported by the finding that phosphorylated ICD-TrkB shows significantly higher activity than control naive ICD-TrkB. Interestingly, the autophosphorylation rate in the linear phase clearly depends on the ICD-TrkB concentration, whereas the rate of initial autophosphorylation is independent of the concentration of ICD-TrkB in the reaction mixture. This observation suggests a two-step autophosphorylation, first an intramolecular activating step and then an intermolecular step. This mechanism is confirmed by the result that only the later phase of autophos-phorylation is inhibited by addition of glycerol which interferes with intermolecular interactions. Therefore, we propose the mechanism of ICD-TrkB autophosphorylation as a sequential cis/trans phosphorylation.     

A case of relapsed thymic carcinoma that responded remarkably to chemotherapy with CPT-11

A chemotherapeutic protocol for advanced thymic carcinoma has not been established as yet. We described a case of advanced and relapsed thymic carcinoma that responded remarkably to subsequent chemotherapy with CPT-11. A 61-year-old man was admitted to our hospital because of facial edema and general fatigue. Chest X-ray and CT scan showed anterior mediastinal tumor which involved large vessels and pericardium. CT guided needle biopsy yielded a diagnosis of squamous cell type of thymic carcinoma. The patient was initially treated with ADOC (ADM, CDDP, VCR, CPA) chemotherapy and had successfully controlled for six months. However, the mediastinal tumor recurred and radiotherapy and nedaplatin plus ETP therapy were not effective. Then, CPT-11 chemotherapy (80 mg/m2, 2 weeks) was performed. The patient showed a partial response after two courses of CPT-11 chemotherapy. This case suggests that CPT-11 is a useful chemotherapeutic agent for advanced thymic carcinoma.     

Assessment of urinary beta-core fragment of human chorionic gonadotropin as a new tumor marker of lung cancer

BACKGROUND: Some patients with lung cancer have been found to have elevated levels of serum immunoreactive human chorionic gonadotropin (hCG)/hCG beta (IR-beta), but it is uncertain whether it would be valuable as a tumor marker. Recently, IR-beta has been demonstrated to consist of at least three different molecules, intact hCG, free hCG beta, and hCG beta-core fragment (beta-CF), in body fluids. In this study, the authors qualitatively analyzed IR-beta in the serum and urine of patients with lung cancer and assessed its clinical usefulness as a tumor marker. METHODS: Highly sensitive and specific enzyme immunoassays were established to measure intact hCG, free hCG beta, and beta-CF in the serum and urine of patients with lung cancer. RESULTS: Of 99 patients with lung cancer, almost half of the patients achieved positive values of IR-beta in the urine, although only 12 had elevated values of IR-beta in the serum. The greater part of the elevated urinary IR-beta was identified to be beta-CF by gel chromatography on Sephadex G-100 (Pharmacia LKB Biotechnology, Tokyo, Japan), leading the authors to assess its usefulness as a tumor marker for lung cancer. Based on the cutoff value (0.2 ng/mg of creatinine) from healthy subjects, the overall positive rate of urinary beta-CF for lung cancer was 48.5% (48 of 99 patients). The incidence of the marker increased with stage of disease, from 35.7% (15 of 42) in Stage I and 35.7% (5 of 14) in Stage II to 62.5% (20 of 32) in Stage III and 72.7% (8 of 11) in Stage IV. These positive rates exceeded or equaled those of the serum tumor markers, carcinoembryonic antigen, and squamous cell carcinoma (SCC)-related antigen, measured simultaneously in the same patients. The author were encouraged that there was no significant difference in the positive rates of urinary beta-CF between two major types of lung cancer: adenocarcinoma (49.2%) and SCC (45.2%). Immunohistochemical study revealed positive staining of IR-beta in the cancer tissues from 5 of 12 patients with elevated levels of IR-beta, in which most of the positive cases had the elevated levels of serum free hCG beta (> 0.5 ng/ml) and/or urinary beta-CF (> 1.0 ng/mg of creatinine). CONCLUSIONS: Ectopic production of IR-beta by lung cancer is not rare, and urinary beta-CF might be a potential tumor marker of lung cancer.     

Lipopolysaccharide induces manganese superoxide dismutase in the rat pancreas: its role in caerulein pancreatitis

Intraperitoneal injection of lipopolysaccharide (LPS) at a dose of 50 micrograms/kg increased the activity and the mRNA level of manganese superoxide dismutase (Mn-SOD) but did not change those of copper/zinc-SOD (Cu/Zn-SOD) in the rat pancreas. Both the formation of pancreatic edema and the elevation of serum amylase during caerulein pancreatitis were significantly relieved in the rats pretreated with LPS (50 micrograms/kg) compared with the rats without the pretreatment. These results support the view that superoxides play a key role in the pathogenesis of caerulein pancreatitis, and that Mn-SOD in the pancreas may work as a defense against the development of this disease.     

Late local recurrence after radiotherapy for tongue and early glottic carcinoma

BACKGROUND/AIM: Late local recurrence after radiotherapy for tongue and early glottic carcinoma is rarely discussed. In the head and neck cancer, approximately 90% of local recurrence occurred within 2 years after radiotherapy. However, we found that late local recurrence after radiotherapy for glottic cancer was not rare. Our aim was to evaluate the late local recurrence after radiotherapy for early glottic and tongue cancer. PATIENTS AND METHODS: From 1967 through 1982, 633 patients with tongue carcinoma and 330 patients with early (T1T2N0) glottic carcinomas were treated at the Department of Radiology, Osaka University Hospital. Of these 821 patients, 329 patients with tongue carcinoma and 221 patients with early glottic carcinoma survived at 5 years after radiotherapy without local recurrence. For tongue carcinoma, patients were divided by T category. For early glottic carcinoma, patients were divided by the tumor response at 40 Gy. RESULTS: Late local recurrence occurred in 23 of 329 patients (7%) with tongue carcinoma, and in 9 of 221 (4%) with early glottic carcinoma. For tongue carcinoma, late recurrence occurred in 19 of 249 patients (8%) in stage I and II, and 4 of 80 patients (5%) in stage III and IV. For glottic carcinoma, late recurrence occurred in 8 of 137 patients (6%) with tumor clearance at 40 Gy and 1 of 63 patients (2%) with tumor persistence at 40 Gy. The incidence of double cancer was also evaluated. Of 329 5-year survivors with tongue carcinoma, 39 patients (12%) had another malignancy, and 26 patients of 221 5-year survivors with early glottic carcinoma (12%) had also another malignancy. Of 39 double primaries of tongue carcinoma, 10 patients (26%) had head and neck malignancies, and none of 26 double primaries of early glottic carcinoma. CONCLUSION: Late local recurrence was not rare in tongue and early glottic cancer. Poor prognostic group showed lower incidence of late recurrence than good prognostic group. This result suggests that secondary tumor at the same site of primary tumor is late local recurrence.     

Agglomeration of magnesium oxide particles formed by the decomposition of magnesium hydroxide

Agglomeration of magnesium oxide (MgO) particles was studied by decomposing magnesium hydroxide (Mg(OH)₂). The properties of agglomerates varied according to the decomposition temperature region: (i) below 650° C, (ii) 650° C to 850° C, (iii) 850° C to 1050° C, and (iv) 1050° C to 1200°C. In region (i), the original Mg(OH)₂ frameworks or pseudomorphs remained in the powder and showed agglomeration. The strength of agglomerates containing the pesudomorphs was about 50 MPa; the primary particles in pseudomorphs are bonded chemically by the interaction of MgO and residual water. In region (ii) the pseudomorphs began to show some fragmentation: the bonding strength of these pseudomorphs reduced rapidly. In region (iii), both crystallite and primary particles were grown by the sintering; this growth may be due to an increase in contact area based on the collapse of pseudomorphs. The primary particles whose necks were grown by the sintering could be easily pulled apart by grinding. In region (iv) pore growth due to the rearrangement of primary particles caused the suppression of both densification rate and crystal growth of MgO.     

Frequency stabilisation of semiconductor laser using atomicabsorption line under direct FSK

The oscillation frequency of an AlGaAs laser diode is stabilised using the Rb-D2 absorption line (780 nm) under the direct frequency shift keying (FSK) condition. Only one side (mark or space) frequency signal is used to obtain the feedback signal for stabilisation in this system. The stability obtained is almost the same as that of the case without FSK     

A GaAs MMIC chip-set for mobile communications using on-chipferroelectric capacitors

A GaAs MMIC chip-set applicable for various mobile communication systems has been developed. The chip-set consists of (1) low-noise amplifier (LNA) with diversity switching capability and (2) integrated mixer with an amplifier for local oscillator signal. The notable feature of these ICs is the dramatic reduction of pin counts and the improvement of high frequency characteristics due to on-chip ferroelectric bypass capacitors of barium strontium titanium (ϵ_r=300). These ICs can be mounted in a small mini-mold package with 6-pin counts