177,293 research outputs found
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
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
The profile of bile acids and their sulfate metabolites in postprandial human serum suggest sex-related differences
No full textDiet:gut microbiota interactions are likely to play a key role in influencing hepatic bile acids (BAs) neosynthesis and production of secondary and tertiary BAs in the intestine. There are few studies exploring how diet:microbe interactions can modulate BAs profile in human. Probiotic, polyphenols and prebiotic fibers like oat β-glucans has been shown to modulate the gut microbiota composition and consequently the BAs pool. On the other hand certain fibers, apple pectin, proanthocyanidins or condensed tannins, may sequester BAs, driving them distally into the colon where they may be excreted or transformed by microbiota. In this work developed an isotopic dilution LC–ESI-MS/MS method for a comprehensive analysis of BAs in human serum with application to kinetic study with Vaccinium corymbosum and Vaccinium myrtillus. We used a combination of quantitative (LC-TripleQuad) and qualitative (LC-HR-Orbitrap) analysis for discovery of BAs isomers. Their presence was confirmed thanks to fragmentation pattern similarities with analytical standards and mass accuracy measurements in full scan and MS/MS modes. This method was applied to study BAs levels in serum from a kinetic study over 6h postprandial after consumption of two types of berries. For the first time sulfates conjugated forms of BAs were measured and quantified using deuterated bile acids internal standards. With this method it was possible to separate forty nine bile acids and quantify them at trace nM levels. A strategy of scheduled/ unscheduled injections of real samples allowed us to find additional BAs isomers not a priori included in the method, while high resolution full scan and MS/MS fragmentation analysis confirmed their structural adherence to the bile acid family. The applicability of the proposed method was assessed by analysing serum samples from a nutrikinetic challenge study with two different types of berries, which showed high inter-individual differences both in the concentrations and composition of plasmatic BAs in fasting and postprandial state. We found differences in bile acids quantity and time reaching maximal BAs concentrations between males and females, suggesting higher BA concentrations in males. Despite high inter-individual variability in fasting and postprandial states, we found three possible subgroups thorough hierarchical clustering. Values regarding the variability among all study volunteers and proportional distribution of BAs were in agreement with previous data measured in independent populations. These findings open new perspectives in understanding the role of the diet, and give an important impact on understanding of bile acid homeostasis and on future personalized nutrition strategie
The role of metabolomics in personalized nutrition using food bioacties
No full textIn the modern era of nutrition, metabolomics has revealed high potential in a wide range of applications. One of the most popular usages has been focused on the detection of novel bioactive compounds in food. At the same time, metabolomics has also proven to be a valuable tool for the discovery of new biomark ers of food intake to overcome the limitations of traditional methods of dietary assessment. This has led to a better understanding of how dietary constituents’ impact health and modulate metabolic pathways. Such studies revealed that different subjects have their own metabolic profile (also known as metabolic phenotypes or metabotypes). Different metabolic phenotypes, in turn, have been associated to the differ ent responses of individuals to diet highlighting the need to study more in depth the main determinants of inter-individual variation in response to food consumption. This stratification of individuals in metabotypes could be used for delivering customized nutritional recommendations and/or tailored dietary interventions at individual level, which can then be used to achieve personalized nutrition. The metabotype of an individ ual is also affected by the persons’ microbiota and their own metabolites. The microorganisms present in the gut are often capable of metabolizing some of the dietary components that humans are unable to pro cess, transforming them into potential bioactive compounds. However, the widely described differences in the gut microbiome composition between subjects add an additional challenge in the effective translation of scientific knowledge in clinical practice in the era of precision medicine. In this talk, I will discuss existing applications of different metabolomics approaches in the field of personalized nutrition towards a more objective dietary assessment using food intake biomarkers, and in the stratification of individuals accord ing to their metabolic phenotypes, while considering the major challenges that remain to be addressed to move forward in the discipline of personalized nutrition
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
Isotopic dilution method for bile acid profiling reveals new sulfateglycine-conjugated dihydroxy bile acids and glucuronide bileacids in serum
No full textAn ultrahigh performance liquid chromatography tandem mass spectrometry method (UHPLC-MS/MS) was developed for the determination of 41 target and 8 additional bile acids isomers (BAs) in biological fluids. BAs were analysed by solid-phase extraction on 50 μL biofluid-aliquots, followed by a properly optimised 27 min-chromatographic run. The method provided high sensitivity (limits of detection 0.0002–0.03 μM, limits of quantitation 0.0007–0.11 μM), linearity (R2>0.99) and precision (relative standard deviations ≤16%). A strategy of scheduled/ unscheduled injections of real samples together with neutral loss (80 Da and 176 Da) scans allowed us to find additional bile acid isomers not a priori included in the method, while high resolution full scan and MS/MS fragmentation analysis confirmed their structural adherence to the bile acid family. Moreover this is the first study quantifying four sulfate glycine conjugated-dihydroxy bile acid isomers, independently of the diet and postprandial time. Application to a dietary intervention kinetic study confirmed the existence of possible metabotypes amongst the study population (n = 20). A trend differentiating males from females was observed suggesting that serum samples from women contained smaller amounts of certain bile acid
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
Profiling neuroactive compounds in organic, conventional, and processed tomatoes
No full textDespite growing evidence linking diet to neurodegenerative diseases, the connection re-mains unclear. Tomatoes, a widely consumed food, have been proposed as potential sources of neuroactive compounds. Using LC-MS/MS, we profiled organic and conven-tional “datterini,” plump, and processed tomatoes. Six carotenoids were quantified, with phytoene and lycopene being the most abundant. Multivariate analysis revealed that pro-cessing and variety, rather than organic vs. conventional methods, drove dataset variabil-ity. Seventy neuroactive compounds were identified, some distinguishing tomato variety, processing, and/or production methods. Processed tomatoes generally showed higher abundance of neuroactive compounds than fresh tomatoes, and “datterini” tomatoes con-tained more neuroprotective compounds than plump tomatoes. Organic “datterini” did not have higher neuroprotective compound levels than conventional ones. These findings suggest thermal processing may alter the compositional quality of tomatoes, potentially enhancing the levels of certain bioactive constituents, while organic cultivation does not inherently increase the abundance of neuroprotective compounds. Overall, tomatoes rep-resent a complex source of both neuroprotective and neuro-disrupting compounds, war-ranting further research on their bioaccessibility and physiological relevanc
Does Apico-Coronal Implant Position Influence Peri-Implant Marginal Bone Loss? A 36-Month Follow-Up Randomized Clinical Trial
No full textPurpose: Preserving peri-implant bone and reducing exposure of the rough implant surface might influence long-term outcomes of implant therapy. The aim of this study was to compare peri-implant clinical and radiologic parameters after crestal and subcrestal dental implant placement at 36 months’ follow-up. Materials and Methods: We carried out a randomized clinical trial involving partially edentulous patients in need of an implant-supported, partial fixed dental prosthesis or a single crown. Patients were randomized according to the implant insertion depth: implants placed approximately 2 mm below the bone crest (test group) or implants placed at bone crest level (control group). They were evaluated 6, 12, 24, and 36 months after prosthetic loading. Peri-implant marginal bone loss was the primary outcome, and the following secondary outcomes were registered: coronal bone changes, plaque index, probing depth, modified bleeding index, retraction and width of the peri-implant mucosa, and peri-implant health condition. Implant survival and success rates after 36 months’ follow-up were calculated. Results: The study comprised 128 patients (83 men and 45 women; mean age, 54.4 ± 12.2 years) and a total of 265 implants (133 in control group and 132 in test group). No statistically significant differences in the peri-implant clinical parameters were found. After 3 years’ follow-up, 53.4% of the crestal implants and 25.8% of the subcrestal implants presented marginal bone loss, with a mean exposed rough surface of –0.2 ± 0.3 mm and –0.09 ± 0.1 mm, respectively (P =.001). The overall success rate was 99.6%. Conclusions: Crestal and subcrestal implants showed similar clinical outcomes 3 years after prosthetic loading. Significant differences were observed in the radiologic parameters, showing less peri-implant marginal bone loss with subcrestal implants
Intern experience at Honeywell, Inc., Large Information Systems Division: 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 references (leaves 169-173)This report describes the author's internship assignment at Honeywell
Inc. - Large Information Systems Division from January, 1982 through August, 1982. The purpose
of the assignment was to fulfill the internship requirements of the Doctor of Engineering
Program. During the internship, the author held the position of VLSI design engineer, where he
worked on a predefined project. The project's objective was to evaluate how circuit designs
based on an advanced CMOS process, can be applied to hardware products at LISD. The internship
allowed the author to successfully apply the MOS circuit design training, which ws developed
at Texas A&M, to an industrial project. In addition, involvement in different activities
and exposure to the various problems not encountered in academia, made this internship an
invaluable experience
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