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Some elementary mathematical properties of term matching document retrieval systems are developed. These properties are used as a basis for a new file organization technique. Some of the advantages of this new method are (1) the key-to-address transformation is easily determined; (2) the documentary information is stored only once in the file; (3) the file organization allows the use of various matching functions and thresholds; and (4) the dimensionality of the transform is easily expanded to accommodate various sized data bases.

AbstractMicron-scale droplets of nematic liquid crystal, embedded in a solid polymer matrix, are the active conponents of polymer dispersed liquid crystal (PDLC) shutters. An electric field is used to orient the director fields in PDLC droplets and thereby control the transmission of light through the film. We have calculated the director configurations of PDLC droplets dispersed in a ferroelectric matrix, which could be used to stabilize the oriented state. Our approach is based on the Landau-de Gennes model free energy and determines the stable configuration by numerical solution of the Euler-Lagrange equations for the director field. Unlike earlier work on this subject, we take into explicit account the effects of spatial variations in the electric field that arise due to the liquid crystal's anisotropic polarizability. We find that these inhomogeneities are significant in determining the stable director configuration, and predict a greater range of stability for the radial phase than that obtained using the uniform-field approximation.

Although immunodetection of hepatitis B core antigen (HBcAg) in the liver has long been recognized as a marker of active hepatitis B virus (HBV) replication, the correlation between the level of viral replication and the degrees of expression of HBcAg in hepatocytes remains to be established. In this study, we examined the semiquantitative relationship between the level of HBV DNA in serum and the degree of expression of HBcAg in the hepatocyte nucleus or cytoplasm in 80 adults with chronic hepatitis B. Expression of HBcAg in hepatocytes was studied by the avidin-biotin immunoperoxidase method, and the results were scored on a scale of 0 to 4, values corresponding to the positivity of 0, 1 to 10, 11 to 25, 26 to 50, and > 50%, respectively, of hepatocytes examined. Serum HBV DNA was tested by a liquid hybridization assay, and the results were scored on a scale of 0 to 5, values corresponding to undetectable levels and levels of < or = 50, 51 to 100, 101 to 150, 151 to 200, and > 200 pg/ml, respectively. The results revealed a highly significant, positive correlation between the level of HBV DNA in serum and the degree of expression of HBcAg in nuclei (Spearman rank correlation coefficient [rs] = 0.653, P < 0.001). The mean scores (95% confidence intervals) of levels of HBV DNA in sera of patients whose levels of expression of HBcAg in nuclei received a score of 0 (n = 33), 1 or 2 (n = 35), and 3 or 4 (n = 12) were 1.3 (1.1 to 1.5), 2.5 (2.1 to 2.9), and 3.9 (3.1 to 4.7), respectively. However, no correlation between the level of HBV DNA in serum and the degree of expression of HBcAg in the cytoplasm was noted (rs = 0.026, P > 0.8). In conclusion, the degree of expression of HBcAg in the hepatocyte nucleus but not the cytoplasm can accurately reflect the level of viral replication in patients with chronic hepatitis B.

We have cloned from Neisseria gonorrhoeae MS11 the gene encoding a methylase that modifies the sequence GCCGGC. The corresponding restriction enzyme was also encoded by this clone. Sequence analysis demonstrated that the methylase shares sequence similarities with other cytosine methylases, but the sequence organization of M.NgoMI is different from that seen for other cytosine methylases. A deletion was introduced into the chromosome of N. gonorrhoeae MS11 to produce strain MUG701, a strain that is inactivated in both the methylase and the restriction genes. Although this strain no longer methylated its DNA at the NgoMI recognition sequence, cells were viable and had no other significant phenotypic changes. Transformation data indicated that MS11 does not produce enough restriction activity to block plasmid transformation in the gonococcus, even though restriction activity could be demonstrated in E. coli containing the cloned gene.

We have cloned DNA methyltransferases (MTases) from various strains of Neisseria gonorrhoeae. Each of these clones represents a single specificity, indicating that the multiple gonococcal MTase specificities are encoded by monospecific MTases. The DNAs of five strains (FA5100, F62, MS11, Pgh3-2, and WR302) were digested with NheI, SpeI, or NheI plus SpeI and subjected to pulsed-field gel electrophoresis. The DNA MTase clones were used to probe Southern blots of these pulsed-field gels to determine whether the MTase genes are linked and whether there are strain-to-strain differences. The results indicate that none of these genes are closely linked, but variable hybridization patterns indicate that there exist restriction fragment length polymorphisms between the strains tested. Most of the chromosomal regions containing these restriction fragment length polymorphisms are clustered in regions containing gonococcal genes known or suspected to antigenically vary via genetic recombination.

Summary The clinical and pathological features of 22 patients, 11 males and 11 females 17–70 years of age (48.0±16.0 years), with hepatic tuberculosis were reviewed. Five patients had no evidence of extrahepatic tuberculosis (local form), and 17 had the miliary form. The clinical features of the miliary and local forms were similar with pyrexia, abdominal pain, hepatomegaly and body weight loss as the main manifestations. The biochemical findings were also quite similar in reversed albumin and globulin (A/G) ratio (2.9/3.5 vs. 3.2/3.4 g/dl) and disproportionate elevation of alkaline phosphatase (ALP) in comparison with bilirubin values but lower levels of alanine aminotransferase (ALT) (40.4±51.0 vs. 170.8±209.4 U/l; p<0.05) and ALP (208.5±138.9 vs. 389.5±271.1 U/l; p<0.05) in the miliary form. Patients with the local form had higher albumin (3.2±0.8 vs. 2.9±0.7 g/dl), aspartate aminotransferase (AST) (160.4±221.7 vs. 65.9±69.7 U/l), and gamma glutamyl-transpeptidase (?GT) (217.0±144.0 vs. 136.0±92.1 U/l), although the differences were not significant. The histopathological features of the miliary form were also similar to the local form with granuloma, caseation, acid-fast bacilli, fatty change and portal fibrosis as the main findings. The local form revealed more severe signs of hepatocytic damage while the miliary form was more wasting. The results suggest that the miliary and local forms of hepatic tuberculosis had quite similar clinical presentations and pathological features. The biochemical tests suggesting hepatic tuberculosis were reversed A/G ratio and disproportionate elevation of ALP.

Two classes of simple low-rate burst-correcting convolutional codes that meet the Gallager bound ofg/b \geq 1 + R/1 - Rare presented. Special cases of these codes are also shown to meet the Peterson and Weldon bound ofb \leq [\frac{1}{2}(n_A -- 1)]. A third class of low-rate codes that can correct iow-density typeB2bursts is also presented. All three classes of codes are majority-logic decodable and, hence, can be easily implemented.

Based on the Mattsom-Solomon polynomial, a class of algebraic linear error-correcting codes is proposed, which includes the Bose-Chaudhuri-Hocquenghen (BCH) codes, Goppa codes, and Srivastava codes as subclasses. Several constructive bounds on the minimum distance of these codes are derived and are shown to be achievable using either Berlekamp's iterative decoding algorithm or Goppa's method based on divided difference. Moreover, it is shown that this class of codes asymptotically approaches the Varshamov-Gilbert bound asn \rightarrow \infty. Although some binary Goppa codes were previously known to haven \leq 2^m, r \leq m \cdot t, andd \geq 2t+ 1, it is shown that a much larger class of codes also possesses such parameters. Finally, shortened codes are considered. With a limited computer search, a number of good codes were found. It is also observed that the proposed codes have no fundamental difference from those recently given by Helgert.

A new data structure developed in connection with a natural language question-answering system is described. The data structure is based upon a new high-order calculus. It allows a great degree of expressiveness and is suitable for extensive logical deduction. The inadequacies of low-order schemes for the representation of natural language information are given. A formal description of the new high-order structure which overcomes these inadequacies is then presented along with the properties that make it more suitable and attractive for machine processing of natural language information.

Many data-transmission and data-storage systems are corrupted by disturbances of both the burst type and the random type. In this paper two classes of error-correcting codes for use with these systems have been constructed analytically and with the aid of a computer. Although not optimal, these codes do have the advantage of ease of implementation,

We present the case of a female patient in whom acute overt hepatitis developed after 60 days of ketoconazole administration (200 mg/day). A prompt renewed hepatic injury 48 hours after an unintentional rechallenge 30 months later provided definitive evidence for a causative relationship between ketoconazole and acute liver injury. Histological examination revealed acute hepatitis with bridging hepatic necrosis. Clinicians should be aware of this cause and effect relationship between ketoconazole and acute liver injury, which can result in prompt severe acute liver injury after rechallenge.