1,380,774 research outputs found
Activity-rest stimulation protocol improves cardiac assistance in dynamic cardiomyoplasty
No full textEur J Cardiothorac Surg. 2002 Mar;21(3):478-82.
Activity-rest stimulation protocol improves cardiac assistance in dynamic cardiomyoplasty.
Rigatelli G, Carraro U, Barbiero M, Zanchetta M, Dimopoulos K, Cobelli F, Riccardi R, Rigatelli G.
Source
Department of Cardiology, Interventional Cardiology Lab and Cardiomyoplasty Project Unit, Legnago General Hospital, Verona, Italy. [email protected]
Abstract
OBJECTIVE:
No data have ever been published regarding cardiac assistance in demand dynamic cardiomyoplasty (DDCMP). We tested the efficacy of the Doppler flow wire in measuring beat-to-beat aortic flow velocity and evaluating cardiac assistance in demand cardiomyoplasty patients.
METHODS:
The technique was tested in seven patients (M/F=6/1; age=57.1+/-6.2 years; atrial fibrillation/sinus rhythm=1/6; NYHA=1.4+/-0.5). Measurements were done using a 0.018inch peripheral Doppler flow wire advanced through a 5F arterial femoral sheath. Three 1-min periods with the stimulator off and three 1-min periods with clinical stimulation were recorded. We measured peak aortic flow velocity in all beats. Latissimus dorsi (LD) mechanogram was simultaneously recorded.
RESULTS:
Comparison between pre-operative and follow-up data showed significantly higher values of tetanic fusion frequency (TFF) and ejection fraction at follow-up, whereas mean NYHA class was significantly lower. Statistical analysis showed an increase in aortic flow velocity not only in assisted versus rest period, but also in assisted versus unassisted beats (8.42+/-6.98% and 7.55+/-3.07%). A linear correlation was found between the increase in flow velocity and LD wrap TFF (r(2)=0.53).
CONCLUSIONS:
In DDCMP, systolic assistance is significant and correlated to LD speed of contraction; demand stimulation protocol maintains muscle properties and increases muscle performance.
PMID:
11888767
[PubMed - indexed for MEDLINE
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
Dimopoulos, Mr And Family, [No Service Number]
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/381868Surname: DIMOPOULOS. Given Name(s) or Initials: MR AND FAMILY. Military Service Number or Last Known Location: [No Registration Number]. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 47513.211926
Item: [2016.0049.14161] "Dimopoulos, Mr And Family, [No Service Number]
Intern experience at CH���M Hill, Inc.: an internship report
No full textIncludes author's vita"Submitted to the College of Engineering of Texas A&M University in partial
fulfillment of the requirement for the degree of Doctor of Engineering."Includes bibliographical referencesA review of the author's internship experience with CH���M HILL, Inc.
during the period September 1975 through May 1976 is presented. During this nine month
internship the author worked as an Engineer II in the Industrial Processes discipline of this
large consulting engineering firm... The author's prime responsibility was as one of three
lead design engineers on the design of a large wastewater treatment facility for a pulp mill
in Hoquiam, Washington owned by ITT Rayonier Inc. The work generally consisted of the design
of individual treatment units and associated piping and pumping. The purpose of the project
was to provide wastewater treatment capabilities that would satisfy the effluent limitations
(standards) imposed upon the mill by the State of Washington Department of Ecology and the
U.S. Environmental Protection Agency. The author's assignment also entailed necessary
interaction with the project manager and other CH���M HILL design engineers and support staff
members, the client's representatives, and representatives of two other consulting engineering
firms working on the project. Thus, the internship position at CH���M HILL provided considerable
experience coordinating the author's work with the work of other engineers, guiding the design
and administrative efforts of a support staff, and interacting regularly with the client and
other consulting firms. This broad exposure to a variety of engineering and organizational
problems provided a valuable educational experience
Intern experience at the Texas Transportation Institute: an internship report
No full text"Submitted to the College of Engineering of Texas A&M University in partial
fulfillment of the requirements for the degree of Doctor of Engineering."Includes vita (leaf 91)Includes bibliographical references (leaf 57)This report discusses the author's engineering experience at the Texas
Transportation Institute (TTI), Texas A&M University from March 1974 through July 1977. A
report of this experience plus twelve additional hours of academic course work were
substituted for an internship according to requirements established by the College of
Engineering. Although the author could not retroactively establish objectives of the type
associated with a typical internship, the work experience gained could be related to the two
general objectives of an intership: 1. To demonstrate an identifiable contribution to the
organization in which the intern served, and 2. To enable the intern to become aware of the
non-technical aspects of working as an engineer in a non-academic environment. While a member
of the Texas Transportation Institute staff, the author worked on a number of projects in the
areas of highway traffic engineering research and the preparation of continuing education
courses for transportation engineering officials. These assignments were contained within the
Urban Transportation Systems Division of TTI. This report delineates the author's contribution
to four particular projects and discusses the technical as well as non-technical experience
gained from each. Having been exposed to more engineering situations than many of the other
Doctor of Engineering students, the author has already formulated some rather specific
milestones for the future. The Doctor of Engineering program is discussed in conjunction with
its potential for helping the author attain these career goals and objectives. Also, some
thoughts are presented regarding the Doctor of Engineering as a viable alternative to the
Ph.D. in preparing for a career in engineering higher education
Trapping cDNAs coding for receptors and secreted proteins from the salivary glands of the malaria vector Anopheles gambiae.
No full textThe salivary glands of mosquito vectors are interesting organs for at least two reasons: (i) they play a crucial role in pathogen transmission and several evidences suggest that recognition and entry of malaria parasite into salivary glands may be mediated by interactions of the ligand-receptor type (Rosenberg R., 1985, Am.J.Trop.Med.Hyg., 34: 687-691; Barreau C. et al., 1995, Exp. Parasitol., 81: 332-343); (ii) they specifically express and secrete substances with antihaemostatic activities (such as anti-coagulants, vasodilators and inhibitors of platelet aggregation) that increase the ability of mosquitoes to efficiently feed on blood (James A.A., 1994, Bull. Inst. Pasteur 92: 133-150). The salivary glands of Anopheles gambiae are still poorly characterized, specially at the molecular level; moreover, the identification of the sporozoite receptor and the isolation of salivary gland-specific promoters would represent important steps toward the design of new vector control strategies based on the development of transgenic mosquitoes incapable of transmitting malaria. In order to identify receptors and secreted proteins expressed in the salivary glands of An. gambiae we used the Signal Sequence Trap (SST) method (Tashiro K. et al., 1993, Science, 261: 600-603) which allows the trapping, through screening in COS-7 cells, of molecules containing signal peptides. In this system a 5'end-enriched cDNA expression library is directionally cloned in an appropriate plasmid vector, between a promoter that confers strong expression in COS-7 cells and a reporter gene, the α-chain of the human interleukin-2 receptor (Tac) lacking the endogenous signal sequence. cDNAs containing a signal sequence and cloned in frame with Tac can be expressed as fusion proteins on the surface of COS-7 cells and can be easily detected by immunostaining with an anti-Tac monoclonal antibody. The cDNA library is screened by transfecting pools of clones in COS-7 cells. Positive pools are divided in sub-pools and re-screened by immunostaining leading to the identification and isolation of single positive clones. We used poly-A(+) RNA from salivary glands of An. gambiae females to construct a 5'end-enriched cDNA expression library and we did our screening in COS-7 cells using the SST method (plasmid vectors were kindly provided from Prof. T. Honjo, Kyoto Univ., Japan). In a first round of screening we were able to isolate eighteen immunofluoruescent positive clones; these cDNA fragments range in size from ~200 to 550 bp and fifteen of them were unique as shown by sequence analysis. All of them, with only one exception, seem to have a signal peptide fused to the reporter gene so they are likely to code for secreted or type I membrane proteins. RT-PCR analysis revealed that five cDNAs are specifically expressed in female salivary glands while other two are expressed both in male and in female glands. As shown by database similarity searches one of these salivary gland-specific clones is the An. gambiae apyrase (see Lombardo F. et al., this meeting) while other three seem to represent different members of a family of proteins that show similarity to the D7 protein of Aedes aegypti (James A.A. et al., 1991, Mol. Biochem. Parasitol., 44:245-254). The remaining three salivary gland-specific cDNA fragments did not show significant similarity to known proteins in the databases. Preliminary results, obtained by RNA in situ hybridization to whole glands, suggest that also in An. gambiae, as in the yellow fever mosquito A. aegypti, female-specific genes are expressed in the distal-lateral and medial lobes while transcripts expressed both in male and in female glands can be localized only in the proximal-lateral lobes. In conclusion using the SST method we have identified the first genes specifically expressed in the salivary glands of the malaria vector An. gambiae. The method worked very efficiently allowing for the trapping of seven salivary gland-specific cDNAs out of 300 clones screened. Several other cDNAs of interest are expected to be trapped by a more exhaustive screening
The long-wavelength view of GG Tau A: rocks in the ring world
No full textWe present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models
Current and future treatment options for infections caused by multidrugresistant Gram-negative pathogens
No full textThe spread of multidrug-resistant, extensively drug-resistant and pan-drug-resistant pathogens is causing an unprecedented public health crisis. The limited current therapeutic options led to the revival of two 'old' antibiotics - colistin and fosfomycin - for which a better understanding of their pharmacokinetics in the critically ill patient and in specific body compartments is required. Tigecycline's use in clinical practice for nonapproved indication based on its in vitro activity against problematic pathogens requires caution and probably higher doses. Furthermore, all three antibiotics should be used as part of combination regimens in order to prevent resistance and optimize outcomes. The development of new antibacterials in the near future, namely combinations of avibactam, ceftolozane/tazobactam and plazomicin, seems promising; however, they will only partially address current mechanisms of resistanc
EC8-based seismic design and assessment of self-centering steel frames with viscous dampers
No full textThis paper focuses on seismic design and assessment of steel self-centering moment-resisting frames (SC-MRFs) with viscous dampers within the framework of Eurocode 8 (EC8). Performance levels are defined with respect to drifts, residual drifts and limit states in the post-tensioned (PT) connections. A preliminary pushover analysis is conducted at the early phase of the design process to estimate rotations and axial forces in post-tensioned (PT) connections instead of using approximate formulae. Different designs of an SC-MRF with viscous dampers are considered to investigate all possible scenarios, i.e. use of dampers to achieve drifts significantly lower than the EC8 drift limit; to significantly reduce steel weight without exceeding the EC8 drift limit; or to reduce steel weight and achieve drifts lower than the EC8 drift limit. Nonlinear dynamic analyses using models capable of simulating all structural limit states up to collapse confirm the minimal-damage performance of the SC-MRFs. It is shown that the use of the preliminary pushover analysis makes the design procedure very accurate in predicting structural and non-structural limit states. Supplemental damping along with strict design criteria for the post-tensioned connections are found to significantly improve the seismic performance of the SC-MRFs. Moreover, the paper shows that SC-MRFs with viscous dampers have superior collapse resistance compared to conventional steel MRFs even when the SC-MRF is significantly lighter than the conventional MRF
New advances in dynamic cardiomyoplasty: Doppler flow wire shows improved cardiac assistance in demand protocol
No full textASAIO J. 2002 Jan-Feb;48(1):119-23.
New advances in dynamic cardiomyoplasty: Doppler flow wire shows improved cardiac assistance in demand protocol.
Rigatelli G, Carraro U, Barbiero M, Zanchetta M, Pedon L, Dimopoulos K, Rigatelli G, Maiolino P, Cobelli F, Riccardi R, Volta SD.
Source
Department of Cardiology, Legnago General Hospital, Verona, Italy.
Abstract
No data have been published on real cardiac assistance with demand dynamic cardiomyoplasty. We tested the utility of a Doppler flow wire in measuring beat by beat aortic flow velocity and evaluating cardiac assistance in demand cardiomyoplasty patients. The technique was tested in seven patients (M/W = 6/1; age, 57.1+/-6.2 years; atrial fibrillation/ sinus rhythm = 1/6; New York Heart Association [NYHA] classification = 1.4+/-0.5). Measurements were done using a 0.018 inch peripheral Doppler flow wire advanced through a 5 French arterial femoral sheath. Three 1 minute periods with the stimulator off, and three 1 minute periods with clinical stimulation were recorded. We measured peak aortic flow velocity in all beats. Latissimus dorsi mechanogram was simultaneously recorded. Comparison between preoperative and follow-up data showed significantly higher values of tetanic fusion frequency and ejection fraction at follow-up, whereas mean NYHA class was significantly lower. Statistical analysis showed an increase in aortic flow velocity not only in the assisted versus rest period, but also in assisted versus unassisted beats (8.42+/-6.98% and 7.55+/-3.07%). A linear correlation was found between increase in flow velocity and latissimus dorsi wrap tetanic fusion frequency (r2 = 0.53). In demand dynamic cardiomyoplasty, systolic assistance is significant and correlated to the latissimus dorsi speed of contraction; a demand stimulation protocol maintains muscle properties and increases muscle performance.
PMID:
11814090
[PubMed - indexed for MEDLINE
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