The design of a precompensator for multivariable adaptive control-anetwork-theoretic approach

A network-theoretic approach to the design of a dynamic precompensator C(s) for a multiinput, multioutput plant T(s) is considered. The design is based on the relative degree of each element of T(s). Specifically, an efficient algorithm is presented for determining whether a given plant T(s) has a diagonal precompensator C( s) such that, for almost all cases, T(s)C (s) has a diagonal interactor. The algorithm also finds any optimal precompensator, in the sense that the total relative degree is minimal. The algorithm can be easily modified to work even when a T(s) represented by a nonsquare matrix is given     

Creation of functional materials by use of a slow crystallization process in the nonequilibrium state. I. porous polyamide microparticles

Recently a number of investigations have focused on the self‐organization process from the nonequilibrium state as a new technique that may be used to develop many functional materials. In many cases, amorphous polymers were used and semicrystalline polymers were seldom used in spite of their importance. In this study, we basically investigated the crystal structure, crystalline process, and inner structures of polyamide by using slow phase separation and crystallization process from the nonequilibrium state of the polymer solution. We were able to observe the crystalline lamella growing twisted from the center of the particle. Between these lamella layers, narrow pores were created. From this investigation, we developed a new method to create functional materials of polyamide, the semicrystalline polymer. Porous spherical particles may be properly applied to functional materials such as adsorption materials, catalyst support materials, and so on. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2428–2432, 2003     

Influence of charged droplet cloud on flashover of air gaps for lightning impulse voltage

Transmission lines passing through a mountainous region often are struck by winter lightning. As a result, numerous double-circuit faults occur. Space charge might be responsible for this phenomena. Several investigations on flashover characteristics have been performed focusing on reduction of flashover voltage due to ionic space charge formed by corona discharge. In this paper, flashover characteristics of an air gap within a charged droplet cloud ejected from an airless nozzle using an induction charging method are discussed. The droplets are charged in the range -200 to 200 μC/kg, forming the space-charge density of approximately 13 μC/m³. The flashover voltage and the time lag to flashover were measured when 1.2 × 50 μs lightning impulse voltage applied to a rod-sphere gap is placed within the charged cloud. Flashover voltage for a positive rod increased markedly within a positive charged cloud by increasing the charge-to-mass ratio. The increase of flashover voltage was up to 80 percent in comparison with uncharged droplets. Flashover voltage for the negative rod decreased about 20 percent in the cloud of either polarity. The results show that the presence of charged droplets in the air gaps affects the discharge process significantly.     

The essential Gcd10p-Gcd14p nuclear complex is required for 1-methyladenosine modification and maturation of initiator methionyl-tRNA

Gcd10p and Gcd14p are essential proteins required for the initiation of protein synthesis and translational repression of GCN4 mRNA. The phenotypes of gcd10 mutants were suppressed by high-copy-number IMT genes, encoding initiator methionyl tRNA (tRNAiMet), or LHP1, encoding the yeast homolog of the human La autoantigen. The gcd10-504 mutation led to a reduction in steady-state levels of mature tRNAiMet, attributable to increased turnover rather than decreased synthesis of pre-tRNAiMet. Remarkably, the lethality of a GCD10 deletion was suppressed by high-copy-number IMT4, indicating that its role in expression of mature tRNAiMet is the essential function of Gcd10p. A gcd14-2 mutant also showed reduced amounts of mature tRNAiMet, but in addition, displayed a defect in pre-tRNAiMet processing. Gcd10p and Gcd14p were found to be subunits of a protein complex with prominent nuclear localization, suggesting a direct role in tRNAiMet maturation. The chromatographic behavior of elongator and initiator tRNAMet on a RPC-5 column indicated that both species are altered structurally in gcd10Delta cells, and analysis of base modifications revealed that 1-methyladenosine (m1A) is undetectable in gcd10Delta tRNA. Interestingly, gcd10 and gcd14 mutations had no effect on processing or accumulation of elongator tRNAMet, which also contains m1A at position 58, suggesting a unique requirement for this base modification in initiator maturation.     

Role of peritoneal lavage smears and gastric wall brushing smears in gastric cancer surgery

Examinations of peritoneal lavage smears (LC) and gastric wall brushing smear cytology (BC) appear to be important for determining accurately the stage of gastric cancer. We have been carrying out such examinations during gastric cancer surgery for 7 years. In the present study, we evaluated the results obtained from 287 patients with gastric cancer. Tumor invasion and peritoneal dissemination were correlated with a positive incidence of cancer cells in LC and/or BC. Gastric cancer showing serosal invasion was classified into positive for LC and/or BC and negative for LC and/or BC. Patients positive for LC and/or BC had a poorer prognosis. For future gastric cancer treatment, patients positive for peritoneal cytology are expected to be targeted for intensive treatment during or before surgery.     

Novel small GTPase M-Ras participates in reorganization of actin cytoskeleton

During an attempt to elucidate regulatory mechanisms of skeletal muscle cell differentiation, we cloned cDNAs encoding a novel small GTPase from cDNA libraries of the mouse skeletal muscle cell line C2 and rat brain. It was designated as M-Ras due to the structural similarity to Ras family proteins. M-Ras contained conserved motifs for GDP/GTP-binding and GTPase activities, whereas it varied from the other Ras family proteins at several amino acids within the extended effector domain. From the C-terminal sequence, M-Ras is presumed to be anchored to the cell membrane with a geranylgeranyl group in combination with a polybasic region. Bacterially expressed recombinant M-Ras exerted the GTP-binding and GTPase activities. A mutant M-RasG22V was unable to hydrolyze bound GTP, indicating that it serves as a constitutively active form. Epitope-tagging experiments showed that M-Ras was concentrated on certain plasma membrane-associated structures. Transfection of M-Ras cDNA and microinjection of the M-RasG22V protein into fibroblasts induced formation of the peripheral microspikes. In addition, the actin stress fibers disappeared and instead numerous actin foci were formed in the injected cells. The transfected cells eventually exhibited dendritic appearances with microspikes. Consequently, M-Ras is likely to participate in reorganization of the actin cytoskeleton.     

Four cases of human herpesvirus 6 variant B infection after pediatric liver transplantation

BACKGROUND: Little is known about human herpesvirus (HHV)-6 infection after liver transplantation. We present our experiences with four cases of HHV-6 infection after liver transplantation from living related donors. METHODS: Peripheral blood was collected from four donor and recipient pairs at the time of transplantation and biweekly from the recipients after transplantation. We attempted to isolate HHV-6 and measure antibody titers to HHV-6 and HHV-7. RESULTS: HHV-6 was isolated from four recipients approximately 2 weeks after transplantation. A significant rise in HHV-6 antibody titers was observed in four recipients at some point in their course, whereas HHV-7 antibody titers were increased in one recipient. Four isolates were variant B. When HHV-6 was isolated, all recipients had an unexplained fever. CONCLUSIONS: HHV-6 variant B infection after pediatric liver transplantation was confirmed. HHV-6 infection occurred approximately 2 weeks after transplantation. Moreover, there appears to be an association between HHV-6 infection and unexplained fever.     

Potentiation of glucose-induced insulin secretion by fagomine, a pseudo-sugar isolated from mulberry leaves

The mechanisms of potentiation by fagomine, an N-containing pseudo-sugar derived from mulberry leaves, of insulin secretion from isolated rat pancreatic islets in response to glucose was studied. Fagomine at more than 1 mmol/L significantly potentiated insulin secretion induced by 10 mmol/L glucose. The pseudo-sugar, however, did not affect the basal insulin secretion assessed at a glucose concentration of 3.5 mmol/L. The effects of fagomine on 10 mmol/L and 20 mmol/L glucose-induced insulin secretion were not significantly different. Fagomine (4 mmol/L) also potentiated glyceraldehyde-induced insulin secretion, but not the leucine-induced type. Glycolysis assessed by lactate production from glucose was significantly enhanced. The amounts of all intermediates (from glucose 6-phosphate to glyceraldehyde 3-phosphate) of the upper part of the glycolytic pathway in islets incubated with 20 mmol/L glucose were not affected by 4 mmol/L fagomine. The rise in the ATP/ADP ratio through both the glycolytic pathway and the citric acid cycle is believed to be pivotal in glucose- and glyceraldehyde-induced insulin secretion; whereas the ATP/ADP ratio rise through the citric acid cycle via the formation of acetyl-CoA is involved in leucine-induced insulin secretion. Our findings, together with these considerations, suggest that fagomine potentiates glucose-induced insulin secretion through acceleration of some step(s) after the formation of glyceraldehyde 3-phosphate in the glycolytic pathway.     

A period of anaerobic exercise increases the accumulation of reactive carbonyl derivatives in the lungs of rats

Compartment syndrome is caused by an increase in intracompartmental pressure above the capillary level, preventing capillary flow. The acute onset of symptoms occurs after events such as fracture, soft tissue trauma, and revascularization and usually necessitates prompt fasciotomy to avoid loss of function or even necrosis of the enclosed muscle. Compartment syndromes in athletes are of a recurrent nature and are usually referred to as chronic. Nonoperative treatment is often successful. Although compartment syndromes can occur in several anatomic regions, the most commonly seen in athletes involve the leg. Chronic compartment syndromes of the upper extremity are rare, and only a few cases have been reported in the literature. The intracompartmental pressures causing chronic symptoms in these cases ranged between 22 mm Hg at rest and 40 mm Hg after 30 minutes of exercise. Under maximal contraction, a pressure of 58 mm Hg has been recorded. The object of this paper is to report a case of a tennis player where much higher flexor-pronator muscle intracompartmental pressures than those noted above were recorded. We compared the intracompartmental pressure data of this patient with intracompartmental pressures measured in six symptom-free volunteers.