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PubMedDate not supplied

Novel boundary element method for resolving plate bending problems.

This paper discusses the application of the boundary contour method for resolving plate bending problems. The exploitation of the integrand divergence free property of the plate bending boundary integral equation based on the Kirchhoff hypothesis and a very useful application of Stokes' Theorem are presented to convert surface integrals on boundary elements to the computation of bending potential functions on the discretized boundary points, even for curved surface elements of arbitrary shape. Singularity and treatment of the discontinued corner point are not needed at all. The evaluation of the physics variant at internal points is also shown in this article. Numerical results are presented for some plate bending problems and compared against analytical and previous solutions.

Algorithms↗
PubMed1998

Charting the information technology direction for an integrated delivery system.

Automating the healthcare integrated delivery system requires a special set of skills, talent, and communication that goes beyond the capability of the i.t. manager alone. Bringing together all elements of the integrated delivery system and forming a well-integrated information environment will require a level of teamwork rarely seen in any industry. Today's IT manager is like an orchestra conductor. He or she should look ahead in the musical composition, manage the tempo, and bring all the sounds of the eclectic set of instruments together in harmony and achievement of the melody. Following the key success factor outlined here may not guarantee success in automating the integrated delivery system, but following them should keep the process harmonious.

Computer Communication Networks↗
PubMed1999

Hybrid enzymes.

Combining structural elements belonging to different proteins is a powerful method for generating proteins with new properties. Progress based on detailed structural and functional analysis enables a better integration of the elements to be fitted together while preserving or creating functional interactions between them.

Allosteric Regulation↗
PubMed1996

A resolvase-like protein is required for the site-specific integration of the temperate lactococcal bacteriophage TP901-1.

The integration system of the temperate lactococcal phage TP901-1 was characterized in Lactococcus lactis subsp. cremoris LM0230 and MG1363 with the use of deletion derivatives of the integration vector pBC143 (B. Christiansen, M. G. Johnsen, E. Stenby, F. K. Vogensen, and K. Hammer, J. Bacteriol. 176:1069-1076, 1994). The phage-encoded elements necessary for integration were localized on a 2.8-kb NsiI-EcoRI fragment including the phage attachment site, attP. This fragment was DNA sequenced, and sequence analysis revealed three putatively expressed open reading frames, Orf1, Orf2, and Orf3 By the introduction of mutations within the orf1, orf2, and orf3 genes, it was shown that only Orf1 was necessary for the integration process. Furthermore, it was found that Orf1, attP, and a 425-bp region upstream of the orf1 gene are sufficient for integration. Orf1 contains 485 amino acids and is located just upstream of attP. The N-terminal 150 to 180 amino acids of Orf1 showed 38 to 44% similarity to the resolvase group of site-specific integrases, while no similarity to known proteins was found in the C-terminal end. Bacteriophage TP901-1 therefore contains a unique integration system that does not resemble the Int class of site-specific integrases usually found in temperate bacteriophages. The constructed integration vector, pBC170, integrates into the chromosomal attachment site very efficiently and forms stable transformants with a frequency corresponding to 20% of the transformation efficiency.

Amino Acid Sequence↗
PubMed2006

Continuous flow analytical microsystems based on low-temperature co-fired ceramic technology. Integrated potentiometric detection based on solvent polymeric ion-selective electrodes.

In this paper, the low-temperature co-fired ceramics (LTCC) technology, which has been commonly used for electronic applications, is presented as a useful alternative to construct continuous flow analytical microsystems. This technology enables not only the fabrication of complex three-dimensional structures rapidly and at a realistic cost but also the integration of the elements needed to carry out a whole analytical process, such as pretreatment steps, mixers, and detection systems. In this work, a simple and general procedure for the integration of ion-selective electrodes based on liquid ion exchanger is proposed and illustrated by using ammonium- and nitrate-selective membranes. Additionally, a screen-printed reference electrode was easily incorporated into the microfluidic LTCC structure allowing a complete on-chip integration of the potentiometric detection. Analytical features of the proposed systems are presented.

Ceramics↗
PubMedDate not supplied

Computer graphics and developmental theory: a powerful partnership.

Educating student nurses to successfully use computer technology involves conscientious planning from nursing faculty responsible for curriculum integration. Many computer elements may be considered such as computer literacy, word processing, and computer assisted instruction. Database programs, spreadsheet applications, and statistical packages are also often incorporated into curriculum integration efforts. Computer graphics and desk-top publishing can also be used as an effective teaching strategy. The following describes an attempt to combine a creative teaching approach for developmental theory within a course on human development while expanding on students' computer skills in the field of computer graphics.

Computer Graphics↗
PubMedDate not supplied

Visual processing of configuration-dependent spatial characteristics of shapes and patterns. A model useful in the study of the role of the departure from circularity or dispersion of shapes in human visual perception.

In this work a theoretical model was used in combination with testings on normal subjects to get more insight in the role of the departure from circularity or dispersion of the shapes in visual perception. The model was inspired by the observation that the intensity of the effect of a given level of contrast of a shape usually increases, for the same area, with the shape being better concentrated around a center. The model introduces as a measurable characteristic the degree of concentration or dispersion of a shape with respect to a center. The measure was based on the maximum of the convolution integral of the characteristic function of the shape with the weighting function 1/2 pi r, r being the distance between the point of convolution and the surface element to be integrated. A program for the calculation of the degree of concentration of figures and other related processing operations was developed in Turbo Pascal language on a 486 PC. The program included the possibility to generate various figures and to operate on them various transformations such as strangulation, fragmentation with separation of fragments. The model introduces a center of the figure, the point best surrounded by the whole figure, with a geometric and visual significance, as resulting from the good concordance between its calculated and perceived positioning in different relatively simple shapes. In symmetrical compact figures subjected to a central separation or narrowing two centres appear entering the two resulting nuclear parts; a good concordance between model and perception was again observed in this transition to two centres and their subsequent positions in the two nuclear parts. In accord to model prediction, testings showed a very pronounced dependence of the summation efficiency over a contrasting area on the degree of dispersion of the area. This is reflected in the drastic decrease upon figure dispersion of the intensity with which a given brightness or colour contrast is perceived. Thus, the model gives a better explanation and a more efficient way to approach the great capacity of the visual system to disclose more compact shapes or agglomeration zones in a complex visual scene. This capacity is to a large extent due to the increase in the intensity with which a given contrast is perceived, occurring in these conditions. This intensity, which strongly depends on the degree of concentration or dispersion of the figure, becomes an important additional signal leading to the accentuation of the difference between compact and rarefied shapes. The model based on the degree of concentration determined around a centre, although useful for finding a centre and applicable satisfactorily to many shapes, do not cover well all aspects of shape dispersions. In shapes without a dominant central part the confrontation model-testing showed an important involvement in global perception of all local concentrations, not only central but also peripheral, the later underestimated in our model. The model can be however improved by taking into account also such local concentrations.

Form Perception↗
PubMed1991

4',4'' adenyltransferase activity on conjugative plasmids isolated from Staphylococcus aureus is encoded on an integrated copy of pUB110.

In staphylococci, linked resistance to the aminoglycosides kanamycin, neomycin, paromomycin, and tobramycin (KmNmPmTmr) is generally mediated by an aadD determinant which encodes production of an adenyltransferase aminoglycoside modifying enzyme, AAD(4',4''). The aadD resistance determinant is located on small multicopy plasmids such as pUB110, and has also been found on large multiresistance plasmids and on the chromosome in some strains. Examination of two conjugative plasmids from strains of Staphylococcus aureus isolated in North America indicated that the aadD determinant on these plasmids is located on an integrated copy of pUB110. The integrated pUB110 is flanked by direct repeats of the staphylococcal insertion sequence IS257. Analysis of the conjugative plasmid pSK41 showed an 8-bp duplication of the pUB110 sequence immediately adjacent to flanking IS257 elements, suggesting that integration of pUB110 was mediated by IS257.

Aminoglycosides↗
PubMed1998

Review of the scientific basis for establishing the essentiality of trace elements.

The recent Expert Consultation of World Health Organization (WHO)/Food and Agricultural Organization (FAO)/International Atomic Energy Agency (IAEA) defined essentiality of a trace element as follows: "An element is considered essential to an organism when reduction of its exposure below a certain limit results consistently in a reduction in a physiologically important function, or when the element is an integral part of an organic structure performing a vital function in the organism." This definition omits a previous postulate that the mechanism of action of an essential trace element should be well defined; it also supersedes another criterion, once suggested for essentiality, a normal, rather than log-normal distribution of an element's tissue concentrations. The Expert Consultation offers no generally applicable criteria for the physiological importance of functions, and that determination is left to expert groups charged with setting national and other nutritional recommendations. The use of the term "physiological" rather than "biochemical" strongly implies that neither changes of an element's concentration nor of a specific enzyme function alone are proof of essentiality. Among physiologically important functions are growth, reproduction, longevity, and all metabolic and hormonal functions that bear a clear, inverse relation to disease risk. Finally, the term "consistent" states the need for independent confirmation of the original data, before an element can be recognized as essential. These definitions will be discussed as background for further discussions of our present knowledge of boron (B).

Animals↗
PubMed2004

[Alu elements in the human genome].

BACKGROUND: The sequencing of the human genome has revealed that almost half of the genome consists of interspersed repeats. Among the different types of interspersed repeats in humans, Alu elements are the most frequent ones, and new Alu elements are still integrated into new positions in the humane genome. In this review some consequences of this Alu activity are discussed. The first part of the review is focused on Alu element activity that causes genetic disease while the use of Alu elements as genetic tools for several purposes is discussed in the last part. MATERIALS AND METHODS: This review article is based on a literature search on Medline. RESULTS AND INTERPRETATION: Alu elements cause disease by two different mechanisms. A de novo insertion of an Alu element into, or close to, a gene may disrupt its normal function, while homologous recombination between two Alu elements may result in deletions or duplications that cause genetic disease. The high density of Alu elements in the human genome combined with their absence in non-primate species make them useful as genetic tools. Alu elements also represent "molecular fossils" that give phylogenetic information about primates as well as information about historical DNA rearrangements in the human genome.

Alu Elements↗
PubMed1999

[Foundation of integral care/Sofia Feldman Hospital: an experience of flexible management?].

The purpose of the present study was to verify the correspondence between the administrative experience of the Hospital "Sofia Feldman" and the theory on flexible management proposed by MOTTA (1991) and MEDICI & SILVA (1993). It also described innovation elements for institutional integration with the community, such as the substitute mother, ombudsman and systematic voluntary work, done by Community Association of Friends and Users of Sofia Feldman Hospital. Data were collected with a semi-structured interview, applied to employees of different sectors, aiming at knowing their perception about the administrative model used. The flexible administration characteristics of the hospital were evidenced, however authors found elements of classical administration.

Brazil↗
PubMed1994

Molecular basis of the activation of basal histone H1(0) gene expression.

Histone H1(0) is encoded by a gene that is expressed only in cells committed to differentiation. We have previously cloned the Xenopus laevis H1(0) gene and studied elements involved in the regulation of its expression in transfected Xenopus laevis A6 cells, and in microinjected embryos. In this work, in order to understand the basis of the action of these elements, we used an A6 cell nuclear extract and showed that the H1(0) promoter is able to direct efficient in vitro transcription, which is highly dependent on a functional TATA box. However, in contrast to what we observed in vivo, in transfected A6 cells, the in vitro transcription was independent of major regulatory elements, defined in vivo. We then used this in vitro system to reconstitute H1(0) gene regulation. The creation of a repressive environment by the addition of purified histone H1 to the in vitro transcription system allowed us to obtain transcription dependent on the integrity of the regulatory elements. Investigating the basis of this regulation we found that protein-DNA interaction on the proximal promoter region was dependent on the integrity of proximal elements, and moreover the distal regulatory element, the UCE, was able to modulate this interaction. We conclude that the role of these regulatory elements is to maintain the basal TATA-dependent transcription of H1(0) under repressive condition: i.e., H1-mediated repression of transcription, or chromatin assembly in general.

Animals↗
PubMed2000

c-Myc inhibits CD11a and CD11c leukocyte integrin promoters.

The c-Myc transcription factor is an important regulator of cell growth and differentiation, and its gene repression ability seems to play a key role in Myc-mediated cellular transformation. Since Myc overexpression has been associated with reduced expression of beta1 and beta2 integrins, we have investigated the role of c-Myc on CD11a and CD11c transcription. c-Myc inhibited CD11a and CD11c integrin promoter activity in co-transfection experiments, and similar repression was obtained in cells where c-Myc expression (KmycB) or activity (Rat-1 c-MycER) is inducible. The c-Myc repression on the CD11c promoter was independent of the USF-binding site (USF-150), other putative Myc-binding elements, or the integrity of the initiator (Inr)-like sequence present at the major transcriptional start site. Analysis of deletion and mutant promoter constructs revealed that, in the absence of additional upstream cisacting elements, an AP-1-binding site at -60 (AP1-60) is required for c-Myc repressor activity. The c-Myc repressor activity on both integrin promoters was abrogated by deletion of c-Myc residues 106-143, a domain involved in Inr-dependent transcriptional repression. These results demonstrate a direct effect of c-Myc on integrin gene transcription and suggest the existence of a c-Myc-dependent mechanism for coupling leukocyte integrin expression to the cell proliferative state.

Cell Line↗
PubMed1990

Genetic elements involved in Tn21 site-specific integration, a novel mechanism for the dissemination of antibiotic resistance genes.

Transposon Tn21 codes for a site-specific integration system, which is probably a novel recombination mechanism, responsible for the acquisition of resistance genes in this widespread family of transposons. Using insertion and deletion mutagenesis we have identified the genetic loci of the various recombination hot-spots (RHS) and of the gene product (the integrase) that catalyses the reaction. The site of recombination has been localized in two of the RHSs to the DNA sequence GTTAG, which is present at the 3' termini of a loosely conserved palindromic sequence of approximately 59 bp. This 59 bp sequence, which flanks the inserted genes in a number of naturally occurring transposons, is the only element required in cis for the recombination reaction.

Base Sequence↗
PubMed1991

Preferential Y chromosomal location of TRIM, a novel transposable element of Drosophila miranda, obscura group.

We have isolated a novel transposable element from the Y chromosome of Drosophila miranda (obscura group) which shows an organization intermediate between that of typical retroviruses and the I factor of Drosophila melanogaster. The site of integration of this element, TRIM, is an inverted repeat. On the 5' side the central region of TRIM is bordered by a sequence homologous to the tRNA primer binding site (PBS) and on the 3' side by a sequence homologous to the polypurine tract (PPT). The 5' LTR (long terminal repeat) contains transcription signals, such as a TATA box and a polyadenylation sequence. Three long open reading frames (ORFs) are found within the central region of the transposon. ORF1 and ORF2 show amino acid homology to the I factor of D. melanogaster and to conserved amino acid residues of retroviral reverse transcriptases. When used as a probe for in situ hybridization the TRIM element labels about 25 euchromatic sites and the chromocenter in polytene nuclei of D. miranda females. In the chromosome complement of males the polytenized part of the Y chromosome shows about the same number of additional TRIM homologous elements. Thus, as a result of this enrichment of TRIM elements in the Y chromosome, the genomic size of the TRIM population in D. miranda males is approximately doubled.

Amino Acid Sequence↗
PubMed2004

Multiple and overlapping combinatorial codes orchestrate hormonal responsiveness and dictate cell-specific expression of the genes encoding luteinizing hormone.

Normal reproductive function in mammals requires precise control of LH synthesis and secretion by gonadotropes of the anterior pituitary. Synthesis of LH requires expression of two genes [alpha-glycoprotein subunit (alphaGSU) and LHbeta] located on different chromosomes. Hormones from the hypothalamus and gonads modulate transcription of both genes as well as secretion of the biologically active LH heterodimer. In males and females, the transcriptional tone of the genes encoding alphaGSU and LHbeta reflects dynamic integration of a positive signal provided by GnRH from hypothalamic neurons and negative signals emanating from gonadal steroids. Although alphaGSU and LHbeta genes respond transcriptionally in the same manner to changes in hormonal input, different combinations of regulatory elements orchestrate their response. These hormone-responsive regulatory elements are also integral members of much larger combinatorial codes responsible for targeting expression of alphaGSU and LHbeta genes to gonadotropes. In this review, we will profile the genomic landscape of the promoter-regulatory region of both genes, depicting elements and factors that contribute to gonadotrope-specific expression and hormonal regulation. Within this context, we will highlight the different combinatorial codes that control transcriptional responses, particularly those that mediate the opposing effects of GnRH and one of the sex steroids, androgens. We will use this framework to suggest that GnRH and androgens attain the same transcriptional endpoint through combinatorial codes unique to alphaGSU and LHbeta. This parallelism permits the dynamic and coordinate regulation of two genes that encode a single hormone.

Animals↗
PubMed1992

Mutations on free and integrated hepatitis B virus DNA in a hepatocellular carcinoma: footprints of homologous recombination.

Hepatitis B virus nucleotide sequences derived from a hepatocellular carcinoma with free and multiply integrated viral DNAs were determined. Based on a comparison within the X-gene region, cloned free viral DNA previously had been attributed to two distinct groups of preC minus genomes. The comparison of the complete sequence identified one of the genome equivalents as a recombinant between members of these groups. Four different integrated viral DNA elements were cloned and analysed. Similarity to either one of two DNAs representing the two groups of free viral DNA on one hand and the presence of certain mutations only on integrated DNA on the other hand, allowed to recognize distinct segments within the integrants. The data suggest a contribution of different but related genotypes to contiguous stretches of integrated viral DNA via homologous recombination. On this basis an evolutionary relationship between free and integrated DNAs of the preC and the preC minus genotype could be recognized when short sequence segments were compared. The observed coexistence on a given integrated DNA of segments homologous to free viral DNA and of segments homologous to another integrated DNA is consistent with (1) a long lasting association of individual genotypes with dividing cells and (2) multiple integration events being the result of a series of steps not separated by a long time span.

Base Sequence↗
PubMed2003

Efficient gene delivery and gene expression in zebrafish using the Sleeping Beauty transposon.

We used the Tc1/mariner family transposable element Sleeping Beauty (SB) for transgenesis and long-term expression studies in the zebrafish (Danio rerio), a popular organism for clinical disease, vertebrate patterning, and cell biology applications. SB transposase enhanced the transgenesis and expression rate sixfold (from 5 to 31%) and more than doubled the total number of tagged chromosomes over standard, plasmid injection-based transgenesis methods. Molecular analysis of these loci demonstrated a precise integration of these elements into recipient chromosomes with genetic footprints diagnostic of transposition. GFP expression from transposase-mediated integrants was Mendelian through the eighth generation. A blue-shifted GFP variant (BFP) and a red fluorescent protein (DsRed) were also useful transgenesis markers, indicating that multiple reporters are practical for use with SB in zebrafish. We showed that SB is suitable for tissue-specific transgene applications using an abbreviated gamma-crystallin GFP cassette. Finally, we describe a general utility transposon vector for chromosomal engineering and molecular genetics experiments in zebrafish. Together, these data indicate that SB is an efficient tool for transgenesis and expression in zebrafish, and that the transposon will be useful for gene expression in cell biology applications as well as an insertional mutagen for gene discovery during development.

Animals↗