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At least 829 records · Page 46Linked to original sources
PubMed1992

Chromosomal gene transfer elements of the Bacteroides group.

Many human colonic Bacteroides strains carry large ( > 60 kbp) chromosomal elements that can transfer themselves from the chromosome of the donor to the chromosome of the recipient. Most of these elements carry a tetracycline resistance gene (tetQ) and many also carry an erythromycin resistance gene (ermF), but at least one cryptic member of the family has been identified. Molecular analysis of excision and integration events has shown that the self-transmissible Bacteroides elements are not transposons but may represent a new class of integrating elements. The Bacteroides elements are most similar to the streptococcal conjugative transposons, such as Tn916. The Bacteroides Tcr/TcrEmr elements can mobilize DNA that is not contained within the elements themselves. They not only mobilize co-resident plasmids but also cause the excision, circularization and mobilization of discrete unlinked 10-11 kbp segments of chromosomal DNA. Self-transfer and other activities of the Tcr/TcrEmr elements are regulated by tetracycline. Thus, tetracycline not only selects for acquisition of an element but also stimulates element transfer in the first place.

Animals↗
PubMed2000

Modeling of integrated Lamb waves generation systems using a coupled finite element-normal modes expansion method

As part of the research work on Smart Materials and Structures, the development of self-monitoring materials is an emerging issue. In the case of plate-shaped structures, Lamb waves can be used for their relevant properties: long-range propagation, sensitivity to internal flaws and whole-thickness interrogation. This concept requires the use of thin piezoelectric transducers integrated to the structure. Since it is of primary importance to be able to control the generated modes, a suitable modeling technique of this kind of system has been tested on different cases of practical interest. The model uses a coupled finite element-normal modes expansion approach, which allows one to consider either the case of bonded or embedded transducers. The results presented deal with examples of multi-element transducers integrated to composite materials. The influence of parameters such as the dimensions, positions and relative excitation delays of the transducers is studied.

Journal Article↗
PubMed1994

Spatiotemporal boundary formation: boundary, form, and motion perception from transformations of surface elements.

Continuous surface boundaries, object shape, and global motion can be perceived from information that is fragmentary in both space and time. The authors report investigations indicating that accretion and deletion of texture is only 1 member of a broader class of element transformations that produce boundaries, shape, and motion, through spatiotemporal boundary formation (SBF). The authors report 4 experiments exploring SBF. The first 3 examine the class of transformations producing SBF, indicating that local element changes in color, orientation, or location are all effective. A 4th experiment examines temporal constraints on SBF. Integration of local element changes to produce boundaries, form, and global motion appears to be confined to a 165-ms window. Two classes of spatiotemporal integration models are considered; the relation between SBF and other cases of boundary interpolation are discussed.

Adolescent↗
PubMed1990

Integrated patient-specific model of pharmacy practice.

The deficiencies of traditional models for the provision of clinical pharmacy services are discussed, and a patient-specific model that integrates drug distribution and clinical pharmacy functions is proposed. Traditional models have either designated specific individuals as providers of clinical pharmacy services or have combined distributive and supportive services with clinical services. In both cases, clinical services have been of secondary importance. Such models have resulted in inconsistent clinical services for which the patient is not necessarily the primary focus and have made it difficult for pharmacists to understand their mission. The lack of a well-defined primary clinical role for pharmacists has confused health-care providers and created problems for managers attempting to evaluate pharmacists and justify clinical services. The integrated patient-specific model is based on the ethical imperative that the patient must be central to any health-care endeavor. Under this model, clinical pharmacy services are of central importance and distributive services are integrated as a secondary but still very important aspect of comprehensive institutional pharmacy services. Critical elements of the integrated model include a patient-centered philosophy of practice, a definition of clinical pharmacy work, and a managerial framework. The integrated patient-specific model of pharmacy practice puts pharmacists in a professional relationship with patients and explicitly defines clinical services and priorities.

Institutional Practice↗
PubMed1993

Masking, information integration, and tactile pattern perception: a comparison of the isolation and integration hypotheses.

Two competing models of the effects of pattern element proximity, masking, and perceptual integration on the discriminability of spatiotemporal vibrotactile patterns are compared. Kirman's 'integration hypothesis' predicts that pattern perception is facilitated by a process of perceptual integration which requires that pattern elements be presented in close spatial and temporal proximity. Conversely, the 'isolation hypothesis' predicts that the strong masking effects which occur when pattern elements are presented in close proximity impede the perception of patterns. Traditional masking studies do not provide a fair test of these two hypothesis because they rely on methods that measure the subject's ability to identify the target when the target is presented in conjunction with the mask, rather than the discriminability of the complex percept resulting from the integration of the target and mask. To account for this, a new procedure was devised where the amount of interelement masking and the discriminability of the pattern as a whole were measured independently as the spatial and temporal separation of the pattern elements were varied. As expected under both hypotheses, masking between pattern elements increased as either the spatial or the temporal separation between them was decreased. The pattern discrimination data also support the isolation hypothesis in that the patterns were discriminated less well with increasing temporal element separation with a similar but nonsignificant trend in the case of spatial separation. It is concluded that this new methodology should be applied to a wider range of tactile pattern processing situations in order to assess the generality of the results obtained.

Adult↗
PubMed1996

A new variant of B1 elements, vB1, identified upstream of a retroviral integration site.

A new variant of the murine B1 retroposon family, vB1, was identified in antisense orientation 165 bases upstream of the integration site of RFB MuLV in infected NIH3T3 fibroblasts. vB1 revealed a characteristic B1 structure, but contained two additional unique repeats. This variant facilitates identification of related vB1 elements which are considered to represent a minor subgroup of B1 elements.

3T3 Cells↗
PubMed2001

Stable integration of transgenes delivered by a retrotransposon-adenovirus hybrid vector.

Helper-dependent adenoviruses show great promise as gene delivery vectors. However, because they do not integrate into the host chromosome, transgene expression cannot be maintained indefinitely. To overcome these limitations, we have inserted an L1 retrotransposon/transgene element into a helper-dependent adenovirus to create a novel chimeric gene delivery vector. Efficient adenovirus-mediated delivery of the L1 element into cultured human cells results in subsequent retrotransposition and stable integration of the transgene. L1 retrotransposition frequency was found to correlate with increasing multiplicity of infection by the chimeric vector, and further retrotransposition from newly integrated elements was not observed on prolonged culture. Therefore, this vector, which utilizes components of low immunogenic potential, represents a novel two-stage gene delivery system capable of achieving high titers via the initial helper-dependent adenovirus stage and permanent transgene integration via the retrotransposition stage.

Adenoviridae↗
PubMed2003

LINE-1 preTa elements in the human genome.

The preTa subfamily of long interspersed elements (LINEs) is characterized by a three base-pair "ACG" sequence in the 3' untranslated region, contains approximately 400 members in the human genome, and has low level of nucleotide divergence with an estimated average age of 2.34 million years old suggesting that expansion of the L1 preTa subfamily occurred just after the divergence of humans and African apes. We have identified 362 preTa L1 elements from the draft human genomic sequence, investigated the genomic characteristics of preTa L1 insertions, and screened individual elements across diverse human populations and various non-human primate species using polymerase chain reaction (PCR) assays to determine the phylogenetic origin and levels of human genomic diversity associated with the L1 elements. All of the preTa L1 elements analyzed by PCR were absent from the orthologous positions in non-human primate genomes with 33 (14%) of the L1 elements being polymorphic with respect to insertion presence or absence in the human genome. The newly identified L1 insertion polymorphisms will prove useful as identical by descent genetic markers for the study of human population genetics. We provide evidence that preTa L1 elements show an integration site preference for genomic regions with low GC content. Computational analysis of the preTa L1 elements revealed that 29% of the elements amenable to complete sequence analysis have apparently escaped 5' truncation and are essentially full-length (approximately 6kb). In all, 29 have two intact open reading frames and may be capable of retrotransposition.

Animals↗
PubMed2003

Becoming a success story: how boys who have molested children talk about treatment.

This grounded theory study was designed to generate a mid-range theory of treatment from the perspective of boys who have molested children and undergone outpatient treatment. Data included information from seven boys' charts, their written responses to open-ended questions, and audio-taped interviews. The interviews generated a series of statements reflecting the boys' experiences in treatment, which were analysed by the constant comparative method. The basic social process of treatment was 'becoming a success story'. The structural elements of becoming a success story included relapse prevention, compliance and decision-making. The boys integrated these structural elements by talking to people they trusted, listening to what people said, and using what people said to help them do what was right. Becoming a success story took place in a context of family and community support. In its current form, this theory of treatment success can be used in practice to monitor progress through treatment.

Adaptation, Psychological↗
PubMed1996

Integration of the yeast retrotransposon Ty1 is targeted to regions upstream of genes transcribed by RNA polymerase III.

Retroviruses and their relatives, the LTR-containing retrotransposons, integrate newly replicated cDNA copies of their genomes into the genomes of their hosts using element-encoded integrases. Although target site selection is not well understood for this general class of elements, it is becoming clear that some elements target their integration events to very specific regions of their host genomes. Evidence is accumulating that the yeast retrotransposon Ty1 behaves in this manner. Ty1 is found frequently adjacent to tRNA genes in the yeast genome and experimental evidence implicates these regions as preferred integration sites. To determine the basis for Ty1 targeting, we developed an in vivo integration assay using a Ty1 donor plasmid and a second target plasmid that could be used to measure the relative frequency of Ty1 integration into sequences cloned from various regions of the yeast genome. Targets containing genes transcribed by RNA polymerase III (Pol III) were up to several hundredfold more active as integration targets than "cold" sequences lacking such genes. High-frequency targeting was dependent on Pol III transcription, and integration was "region specific," occurring exclusively upstream of the transcription start sites of these genes. Thus, Ty1 has evolved a powerful targeting mechanism, requiring Pol III transcription to integrate its DNA at very specific locations within the yeast genome.

Base Sequence↗
PubMed2001

Modeling and underwater characterization of cymbal transducers and arrays.

The cymbal is a miniaturized class V flextensional transducer that was developed for potential use as a shallow water sound projector and receiver. Single elements are characterized by high Q, low efficiency, and medium power output capability. Its low cost and thin profile allow the transducer to be assembled into large flexible arrays. Efforts were made to model both single element and transducer arrays by coupling finite element analysis (ATILA) and the integral equation formulation (EQI). The pressure and velocity distributions on the surface elements were calculated by ATILA and later used with EQI to calculate the far field properties of the transducer element and arrays. It eliminates the mesh of the fluid domain and makes the 3-D model of a transducer possible. Three-dimensional models of a cymbal transducer and a 3 x 3 cymbal array were developed in the modeling. Very good agreement was obtained between modeling and measurement for single element transducers. By coupling finite element analysis with the integral equation method using boundary elements, acoustic interaction effects were taken into account. Reasonable agreement was obtained between calculation and measurement for a 3 x 3 array.

Journal Article↗
PubMed2004

Proteomics-on-a-chip: the challenge to couple lab-on-a-chip unit operations.

This review describes a vision of a proteomics-on-a-chip device to separate, detect and identify the proteome. It guides the reader towards a development strategy, avoiding some of the pitfalls. It also describes the current state-of-the-art developments in proteomic analysis including available technologies, current market issues, the elements of an envisaged proteomics-on-a-chip device, the required microfabrication processes and the integration of the elements into one device. Address-flow microfluidics is a tool for connecting separation and detection platforms. The final section contains an expert opinion on the recommended development strategies, benefits of proteomics-on-a-chip in the life sciences and the anticipated market.

Drug Design↗
PubMed1995

Internal transcriptional regulatory elements in HIV-1 and other retroviruses.

The transcriptional regulation of retroviruses plays an important role in their pathogenesis. Cis-acting elements have been identified in the long terminal repeat (LTR) at the 5' extremity of the integrated provirus. These elements determine the rate and the site of transcription initiation and consist of arrays of binding sites for transcription factors. Recent studies have demonstrated the presence of additional regulatory elements, located outside of the LTR, within the transcribed region of several retroviruses including avian and murine retroviruses, HIV-1, HTLV-1 and the human spumaretroviruses. This review describes these new observations and analyzes their significance both in terms of retroviral transcriptional regulation and in terms of pathogenesis.

Alpharetrovirus↗
PubMed2004

Formation of SXT tandem arrays and SXT-R391 hybrids.

SXT is an integrative and conjugative element (ICE) isolated from Vibrio cholerae. This approximately 100-kb ICE encodes resistance to multiple antibiotics and integrates site specifically into the chromosome. SXT excises from the chromosome to form a circular but nonreplicative extrachromosomal molecule that is required for its transfer. Here we found that a significant fraction of freshly isolated SXT exconjugants contained tandem SXT arrays. There was heterogeneity in the size of the SXT arrays detected in single exconjugant colonies. Some arrays consisted of more than five SXTs arranged in tandem. These extended arrays were unstable and did not persist during serial passages. The mechanism accounting for the generation of SXT arrays is unknown; however, array formation was not dependent upon recA and appeared to depend on conjugative transfer. While such arrays did not alter the transfer frequency of wild-type SXT, they partially complemented the transfer deficiency of a Deltaxis SXT mutant, which is ordinarily unable to generate the extrachromosomal intermediate required for SXT transfer. Exconjugants derived from donor strains that harbored tandem arrays of SXT and R391, an SXT-related element, contained functional hybrid elements that arose from recA-independent recombination between the two ICEs. Thus, arrays of SXT-related elements promote the creation of novel ICEs.

Chromosomes, Bacterial↗
PubMed2000

Characteristic sequence pattern in the 5- to 20-bp upstream region of primate Alu elements.

We conducted comprehensive sequence analysis of 5' flanking regions of primate Alu elements. Information contents were computed and frequencies of 1024 pentanucleotides were measured to approximate the location of a characteristic sequence and to specify its pattern(s), which may be involved in the integration of Alu elements into their host genomes. A large number of samples was used, the wide region of the 5' end of Alu elements was analyzed, and comparisons were made among different subfamilies. Through our analyses, "TTTTAAAAA" or "(T)(m)(A)(n)" can be stated as a candidate for the characteristic sequence pattern, which resides around the region 5 to 20 base pairs upstream of the 5' end of Alu elements. This characteristic sequence pattern was more prominent in the sequences of younger Alus, which is a strong indication that the sequence pattern has a role at the time of Alu integration.

Alu Elements↗
PubMedDate not supplied

Ethics orientation as a mediator of organizational integrity in health services organizations.

Increasing scrutiny of ethical misconduct by federal and state agencies has prompted health services organizations to adopt codes of ethics and institute legal compliance programs. However, there is little understanding of the impact of ethics programs or the manner in which program elements act to enhance organizational integrity. This study examined the effect of five ethics program elements on organizational integrity and the mediating role played by ethics orientation in this relationship. It found that program elements influence organizational integrity by engendering among employees a values orientation, a compliance orientation, or both. Furthermore, program elements that induced both orientations have a larger impact on integrity. These findings have important implications for health services managers involved in designing and implementing an ethics program.

Attitude of Health Personnel↗
PubMed2006

Mechanosensitive-mediated interaction, integration, and cardiac control.

This review covers aspects of the cardiac mechanotransduction field at different levels, and advocates the possibility that mechanoelectro-chemical transduction forms part of a network of mechanically linked integration in heart-mechanically mediated integration (MMI). It assembles evidence and observations in the literature to promote this hypothesis. Mechanical components can provide the bond between interactions at molecular, cellular, and macro levels to enable the integration. Stretch-activated channels (SACs) exist in the heart, but stresses and strains can affect other membrane channels or receptors. A cellular mechanical change can thus promote several ionic or downstream changes. Cell signal cascades have been implicated and can affect membrane electrophysiology. MMI could shape intracellular and downstream signals using the cytoskeleton and intracellular Ca(2+). MMI also spans other regulatory systems and processes such as the autonomic nervous system (ANS) and operates throughout the whole heart as an integrative system. Finally, supporting the hypothesis, if elements of the normal integration become deranged it contributes to cardiovascular disease and, potentially, lethal arrhythmia.

Animals↗
PubMed1994

Relationship between AIDS and family planning programmes: a rationale for developing integrated reproductive health services.

This paper examines the potential links between family planning and maternal and child health programmes and the emerging needs of the global AIDS epidemic; and assesses the feasibility of organizing comprehensive reproductive health programmes in developing countries to include the prevention and control of reproductive tract infections including sexually transmitted infections as well as HIV/AIDS. The paper discusses arguments opposing the integration of programmes against sexually transmitted infections within family planning and MCH programmes, as well as the programmatic and epidemiological reasons for considering such integration. It is important to determine what elements can be realistically integrated within programmes of varying organizational capacity without compromising their effectiveness.

Communicable Disease Control↗