Repetitive control system: a new type servo system for periodicexogenous signals

A control scheme called repetitive control is proposed, in which the controlled variables follow periodic reference commands. A high-accuracy asymptotic tracking property is achieved by implementing a model that generates the periodic signals of period L into the closed-loop system. Sufficient conditions for the stability of repetitive control systems and modified repetitive control systems are derived by applying the small-gain theorem and the stability theorem for time-lag systems. Synthesis algorithms are presented by both the state-space approach and the factorization approach. In the former approach, the technique of the Kalman filter and perfect regulation is utilized, while coprime factorization over the matrix ring of proper stable rational functions and the solution of the Hankel norm approximation are used in the latter one     

Chemistry and antimicrobial activity of caryoynencins analogs

Caryoynencins (1) are antibiotics isolated from liquid cultures of a plant pathogen, Pseudomonas caryophylli, and are unstable C18 carboxylic acids with a conjugated dienetetrayne structure. Enyne analogs of caryoynencins were synthesized from monosilylated 1,3-butadiyne 2 (n = 2), 1,3,5-hexatriyne 2 (n = 3), and 1,3,5,7-octatetrayne 2 (n = 4) by alkynyl metal addition to 2,4-hexadienal (3) followed by allylic rearrangement and deprotection. Tetraynol 5 (n = 4) thus obtained was resolved by enzyme reactions. The conjugated dienetetrayne compounds are mixtures of 3E,5E- and 3E,5Z-isomers, which equilibrate by room light. 13C-NMR chemical shifts of polyynes obey simple rules, which can be used for signal assignments. Antimicrobial activities of conjugated enynes and related compounds were examined. The tetrayne analog 6 (n = 4) possesses potent antibacterial and antifungal activities, while triyne and diyne analogs 6 (n = 3 and 2) are less active. Chirality does not affect the activities. An isomeric enyne compound, 2,4-tetradecadiene-7,9,11,13-tetrayn-6-ol (8), showed potent activity against Tricophyton.     

Lipase-catalyzed kinetic resolution of 2,3-epoxy-1-tridecanol and its application to facile synthesis of (+)-disparlure

Acylation of (+/-)-2,3-epoxy-1-tridecanol with acetic anhydride in diisopropyl ether by porcine pancreatic lipase yielded (2R, 3S)-2,3-epoxy-1-tridecanol as the remaining substrate with an optical purity of over 99% ee. (+)-Disparlure was synthesized in two steps from this optically active epoxy alcohol.     

Direct detection of Mycobacterium tuberculosis using polymerase chain reaction assay among patients with hepatic granuloma

BACKGROUND: In liver tuberculosis, demonstration of acid bacilli by conventional methods remains futile. Since the definitive diagnosis of liver tuberculosis is based on the histologic evidence of granulomatous process with caseation necrosis, seen in only a third of cases, the diagnosis is made retrospectively by response to empirical anti-tuberculous drug therapy. AIMS: Our objective is to establish a polymerase chain reaction assay for detection of Mycobacterium tuberculosis affecting the liver using the paraffin-embedded liver biopsy specimens obtained from patients with hepatic granulomas. METHODS: As positive control, patients having either "definitive" (n=8) or "presumptive" (n=9) tuberculosis on the basis of clinical, microbiological, histologic data and their positive response to empirical treatment of anti-tuberculous drugs were used. Patients with hepatic granulomas secondary to schistosomiasis (n=6), sarcoidosis (n=2) and other liver diseases (n=10) were used as negative control. RESULTS: Of those patients who were diagnosed as having "definitive" and "presumptive" liver tuberculosis, positivity by one-step polymerase chain reaction was 100% and 44%, respectively. Using the nested polymerase chain reaction, positivity increased to 78% with "presumptive" liver tuberculosis. In contrast, the polymerase chain reaction assays were negative among all patients with hepatic granuloma due to non-tuberculous-in-origin and other liver diseases. CONCLUSIONS: The overall positivity of this polymerase chain reaction assay (88%) compares favorably with that of other conventional methods (12%). Thus, this polymerase chain reaction assay may be a reliable diagnostic tool for liver tuberculosis in a patient population in which the prevalence of diseases associated with hepatic granuloma is common.     

Thermal degradation behaviour of fluorosaponite-α-naphtylamine complex under nitrogen

The layer-type complex of fluorosaponite and-naphtylamine (F-SNC) was heat treated below 1473 K under nitrogen to investigate its thermal degradation behaviour. The most striking characteristic of the behaviour is that the layered structure of F-SNC remained considerably unchanged up to temperatures as high as 1273 K. In order to derive the clay-carbon layer-type complex from the clay-organic compound complex, the degradation behaviour of F-SNC was compared with those of other complexes reported previously. As a result, the most important factor to arise from this work is to use a layered-structural clay with high thermal stability and to intercalate organic compounds, with high carbon yield, as much as possible.     

Control of the near-surface OH concentration of float glass by anodic proton injection

Controlling the OH concentration near the float glass surface was investigated via anodic proton injection into a glass melt under conditions simulating the float glass process. A DC voltage of 1-4 V was applied to the glass at 1000°C between the molten tin as an anode and graphite placed on the glass as a cathode. Although the OH concentration of the glass near the glass/tin interface was controlled to the same level as that in the interior of the glass when a DC voltage of 3 V was applied, the decrease in Na concentration, one order of magnitude greater than the amount of injected protons, was observed around the glass/tin interface. Therefore, the OH concentration by dehydration cannot be restored using anodic proton injection without substantial composition change. Tin was observed to be electrochemically injected into the glass when a DC voltage of >4 V was applied, and majority of the injected protons were released from the glass under the experimental conditions. Finally, the conditions that achieved an OH concentration near the glass/tin interface matching with that in the interior of the glass without substantial composition change around the anode are discussed and proposed.     

A Flash Photolysis Instrument With Digital Smoothing of Data Using a Fast Fourier Transform

ABSTRACT

Laser flash photolysis is a useful technique for disruption of photolabile chemical bonds. The kinetics of the subsequent reformation of such bonds can then be monitored with a suitable detection system. This technique has proven useful for following the reassociation kinetics of hemeproteins with carbon monoxide. We describe the construction of this apparatus using readily available components, along with microcomputer based signal acquisition and digital filtering of data using a fast Fourier transform. The application of this apparatus to measurement of the association of cytochrome P450 with carbon monoxide is described.     

Adenovirus-mediated transduction of Escherichia coli uracil phosphoribosyltransferase gene sensitizes cancer cells to low concentrations of 5-fluorouracil

5-fluorouracil (5-FU), although a widely used chemotherapeutic agent, has a limited effect in the treatment of human solid tumors due to their resistance to the cytotoxic effects of 5-FU. Escherichia coli uracil phosphoribosyltransferase (UPRT) is a pyrimidine salvage enzyme that catalyzes the synthesis of UMP from uracil and 5-phosphoribosyl-alpha-1-diphosphate. The present study demonstrates that adenovirus-mediated transduction of E. coli UPRT gene results in marked sensitization of colon, gastric, liver, and pancreas cancer cell lines to low concentration of 5-FU in vitro. The in vitro bystander effect was observed when only 10% of the hepatoma Hep3B cells were infected with UPRT-expressing adenovirus. In addition, 5-FU treatment of human hepatoma or gastric cancer xenografts in nude mice transduced with UPRT was demonstrated to result in significant in vivo antitumor effects. The adenovirus vector transduction of the UPRT gene followed by 5-FU administration is representative of a new chemosensitization strategy for cancer gene therapy.     

The development of generator modeling techniques for multimode oscillations and study of generator H ∞ control design method for robust control

Modern electric power systems of Japan are characterized by high density, wide area coverage, and a complicated structure. Multimode oscillations occur in the generators connected to the systems. These oscillations represent a combination of high‐ and low‐frequency modes that occur between individual power systems and oscillations of other types, such as the SSR and cross‐compound machine oscillations, which are characteristic mode oscillations of generators. In this paper, we first construct a real model of the generator that realizes the multimode oscillations. Next, model reduction of this real model is carried out, and a design model to be used for the control design is constructed. The H ∞ control design based on the modern control theory is presented by using this design model, which implements the damping of power system oscillations and robust stabilization of other multiple modes. In conclusion, we confirm that the target parameters of the control design have been achieved. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(1): 42–52, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10253