Shallow donor impurities in InP bulk crystals grown by the synthesis, solute-diffusion technique

Far-infra-red photoconductivity measurements are used to study residual shallow donor species in InP bulk crystals grown by the synthesis, solute-diffusion technique. The observation of 1s-2p, m =+ 1 Zeeman transitions between the shallow donor-impurity states reveals that two dominant residual donors are included in the InP bulk crystals having carrier concentrations of less than 1 × 1015 cm?3 The donors are tentatively identified as Si and S.     

A DC-powered Josephson logic family that uses hybrid unlatchingflip-flop logic elements (Huffles)

This paper describes the development of a dc-powered Josephson logic family that uses hybrid unlatching flip-flop logic elements (Huffles). The Huffle circuit used in this study is modified by adding a parallel resistor to the original Hebard-type Huffle circuit. Analysis of the circuit's operation shows that the undesirable hung-up phenomena are prevented by this modification. Based on the result of the analysis, the circuit's parameters are derived and a typical operating margin of ±26% is obtained. Besides AND/OR operations using a threshold logic operation, two-input exclusive OR (XOR), two-input multiplexor (MUX), and three-input majority (MAJ) operations are realized using a Huffle gate in which 2-Josephson-interferometers (2JI) in the standard Huffle gate are replaced by stacked-2JI's. Thus, a Huffle logic family, formed from NOT, AND, OR, XOR, MUX, MAJ, and flip-flop (FF), are constructed. By using this Huffle logic family, a 6-b arithmetic logic operating unit (ALU), a 6-b analog-to-digital converter (ADC), and a 6-b gray-to-binary converter (GBC) have been successfully operated. During high-speed testing, a 1-b comparator was operated up to an input bandwidth of 6 GHz     

Novel sulfated oligosaccharides containing 3-O-sulfated glucuronic acid from king crab cartilage chondroitin sulfate K. Unexpected degradation by chondroitinase ABC

We prepared a series of oligosaccharides from king crab cartilage chondroitin sulfate K after exhaustive digestion with testicular hyaluronidase, and determined the structures of four tetrasaccharides and a pentasaccharide by fast atom bombardment mass spectrometry, high performance liquid chromatography analysis of chondroitinase AC-II digests, and 500-MHz 1H NMR spectroscopy. The tetrasaccharides shared the common core structure GlcAbeta1-3GalNAcbeta1-4GlcAbeta1-3GalNAc with various sulfation profiles. One structure was GlcAbeta1-3GalNAc(4S)beta1-4GlcAbeta1-3GalNAc(4S), whereas three of them have the following hitherto unreported structures including a novel glucuronate 3-O-sulfate: GlcA(3S)beta1-3GalNAc(4S)beta1-4GlcAbeta1-3GalNAc(4S), GlcAbeta1-3GalNAc(4S)beta1-4GlcA(3S)beta1-3GalNAc(4S), and GlcA(3S)beta1-3GalNAc(4S)beta1-4GlcA(3S)beta1-3GalNAc(4S), where 3S or 4S represents 3-O- or 4-O-sulfate, respectively. The structure of the pentasaccharide was determined as GlcA(3S)beta1-3GalNAc(4S)beta1-4GlcA(3S)beta1- 3GalNAc(4S)beta1-4GlcA. Chondroitinase ABC digestion of the tetrasaccharides with GlcA(3S) at the internal position destroyed the disaccharide unit containing GlcA(3S) derived from the reducing side and resulted in only the disaccharide unit from the non-reducing side. In contrast, these tetrasaccharides remained totally resistant to chondroitinase AC-II. The results indicated that it is necessary to reevaluate the disaccharide composition of chondroitin sulfate poly- or oligosaccharides purified from various biological sources, since they were usually determined after chondroitinase ABC digestion. It is probable that the structures containing GlcA(3S) would not have been detected.     

Alternative splicing in fibroblast growth factor receptor 2 is associated with induced epithelial-mesenchymal transition in rat bladder carcinoma cells

We described previously that acidic fibroblast growth factor (aFGF), but not basic fibroblast growth factor (bFGF), can induce the rat carcinoma cell line NBT-II to undergo a rapid and reversible transition from epithelial to mesenchymal phenotype (EMT). We now find that NBT-II EMT is stimulated by keratinocyte growth factor (KGF) in cells grown at low density. Accordingly, a high-affinity receptor showing 98% homology to mouse FGF receptor 2b/KGF receptor was cloned and sequenced from NBT-II cells. Northern analysis indicated that mRNA for FGF receptor 2b/KGF receptor was drastically down-regulated within 1 wk in aFGF-induced mesenchymal NBT-II cells. This decrease coincided with an up-regulation of FGF receptor 2c/Bek, a KGF-insensitive, alternatively spliced form of FGF receptor 2b/KGF receptor. Functional studies confirmed that KGF could not maintain EMT induction on mesenchymal NBT-II cells. FGF receptor 1 and FGF receptor 2c/Bek could also support EMT induction when transfected into NBT-II cells in response to aFGF or bFGF. Such transfected cells could bind bFGF as well as aFGF. Therefore, EMT can be induced through different FGF receptors, but EMT may also regulate FGF receptor expression itself.     

Growth factors increase pericellular proteoglycans independently of their mitogenic effects on A10 rat vascular smooth muscle cells

Several reports suggest that serotonin2A (5HT2A) receptors and this receptor-mediated phosphatidyl inositol (PI) hydrolysis signal transduction system are altered in platelets of depressed patients. Inositol 1,4,5-trisphosphate (Ins[1,4,5]P3), an important component of the PI signaling system, plays a crucial role in various physiological processes by releasing Ca2+ from intracellular stores after binding with Ins(1,4,5)P3 receptors. To examine the role of Ins(1,4,5)P3 receptors in depression, we determined [3H]Ins(1,4,5)P3 binding sites and expressed protein levels of Ins(1,4,5)P3 receptors in platelets of depressed patients (n=15) and normal control subjects (n=17). We observed that the mean Bmax of [3H]Ins(1,4,5)P3 binding to Ins(1,4,5)P3 receptors was significantly higher in platelets of depressed subjects compared with normal control subjects, whereas there was no significant difference in K(D) between these two groups. The immuno-detectable expressed level of Ins(1,4,5)P3 receptor protein was also significantly increased in depressed patients in contrast to the levels of normal control subjects. Moreover, a significant correlation was observed in Bmax and the protein level of Ins(1,4,5)P3 receptors. The increase in the number of [3H]Ins(1,4,5)P3 binding sites in platelets of depressed subjects appears to be due to an increase in the amount of Ins(1,4,5)P3 receptor proteins. These results suggest that Ins(1,4,5)P3 receptors may be involved in the pathophysiology of depression.     

HLA-A26 subtype A pockets accommodate acidic N-termini of ligands

BACKGROUND: Fiberoptic flexible sigmoidoscopy (FFS) is routinely requested preoperatively as part of evaluation of pelvic masses to exclude colonic involvement by the tumor or concurrent colonic neoplasm. The aim of our study was to evaluate the utility of preoperative FFS in patients with suspected gynecologic malignancy. METHODS: FFS, performed using a 60 cm sigmoidoscope, evaluated (1) presence of bowel involvement by the tumor, (2) extrinsic compression by the tumor, and (3) presence of colonic neoplasms. FFS findings were correlated with surgical findings. RESULTS: A total of 107 women underwent preoperative FFS and subsequent surgery. Eleven patients (11%) had lower gastrointestinal symptoms. At surgery, 63% of pelvic tumors were malignant and 37% were benign. The most common abnormality at FFS was colonic polyps in 23 patients (21%). Colonic adenomas were found in 11 patients (10%). Extrinsic compression by the tumor without mucosal abnormalities was seen in 15 patients (14%). The most common intraoperative finding was tumor adhering to the bowel in 18 patients requiring dissection, but only 1 patient required bowel resection. Eight of these 18 patients had preoperative lower gastrointestinal symptoms. All 15 patients with extrinsic compression at FFS had tumor adhering to the bowel. CONCLUSIONS: Pelvic masses cause extrinsic compression at FFS in 14% of patients. This is suggestive of tumor adherent to the bowel at surgery. However, bowel resection is rarely required because of tumor involvement. Most patients with bowel adherence by tumor have lower gastrointestinal symptoms. Colonic adenomas are found in one tenth of patients, mostly in patients older than 50 years of age. Preoperative FFS does not change the surgical management of pelvic tumors. Screening FFS is indicated in all patients with pelvic tumors over age 50, as in persons with average risk, but is otherwise unnecessary in evaluation of pelvic masses.     

Familial occurrence of congenital bile duct cysts

Congenital bile duct cysts are now a well-documented anomaly of the biliary tree, and have become more common in Japan. Familial occurrence of congenital bile duct cysts, however, is extremely rare, with only six reported cases in the literature. We report a familial pattern of congenital bile duct cysts in a mother and her daughter. A 33-year-old female was admitted for evaluation of right upper quadrant abdominal pain and fever 6 days after an uneventful delivery of her second child. A computed tomography (CT) and ultrasound scan (US) revealed an obstructed biliary tract. Percutaneous transhepatic biliary drainage was then performed, and a cholangiogram revealed a Scholtz type B choledochocele without an anomalous connection of the pancreaticobiliary ducts. Endoscopic US demonstrated that the choledochocele was associated with a stone in the cyst. A pylorus-preserving pancreatoduodenal resection was performed, and a histological study revealed that the choledochocele was lined by biliary mucosa without evidence of malignancy. The newborn infant had an abdominal tumour. An US and CT revealed a congenital bile duct cyst. An operation was performed and the intraoperative cholangiogram showed an Alonso-Lej type I congenital bile duct cyst with an anomalous connection of the pancreaticobiliary ducts. Whether congenital bile duct cysts are hereditary remains to be elucidated.     

Reversible crosslinking in cellulose. I. Determination of mercaptan and disulfide in modified cotton

Mercaptan and disulfide contents of modified cotton fabrics could be determined by application of Leach's polarographic method for wool, with minor modification. It was found that mercaptocellulose prepared by the reaction of tosyl cellulose and potassium thiolacetate followed by alkaline hydrolysis contained considerable amounts of disulfided in addition to mercaptain. Iodometric titration of mercaptocellulose gave a higher value of mercaptan than that obtained by the polarographic method. The mercaptan and disulfide contents and methylene blue uptake of the iodine-treated samples indicate that some of the mercaptan groups further undergo oxidation to acidic groups as a result of the iodine treatment. The spatial effect in the oxidation of mercapto groups in modified cotton is briefly discussed.