47 research outputs found
Material characterization of Guadua bamboo and the environmental feasibility of structural bamboo products
No full textThesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 52-55).Bamboo has long been used in vernacular construction because of its high strength, rapid growth rate, and global abundance. Bamboo is increasingly being used in contemporary architecture as a sustainable alternative to wood and other building materials. Forming bamboo into a structural composite can improve mechanical performance, durability, and joining, which can open up new structural applications and design possibilities as well as remove the stigma that bamboo is the "poor man's timber". This study aims to characterize the radial and longitudinal variation in the microstructure and mechanical properties of Guadua bamboo (Guadua angustifolia kunth) in order to inform efficient material use in a composite. The study found a linear relationship between the MOE, MOR, and compression strength with density. Through analysis of micrographs, the density was correlated to the area fraction of sclerenchyma fiber sheaths. Results from nanoindentation confirmed that the fiber properties did not vary with position. Further the environmental impact in the form of exhaustion of energy found that processed bamboo had a mechanical advantage over raw bamboo culm and lower energy input in manufacturing but superior performance in comparison to wood composites.by Arfa N. Aijazi.S.B
Machine learning paradigms for building energy performance simulations
No full textThesis: S.M. in Building Technology, Massachusetts Institute of Technology, Department of Architecture, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 134-138).This research seeks to overcome a technical limitation of building energy performance simulations, the computation time, by using surrogate modeling, a class of supervised machine learning techniques where the output is a performance metric. Though early machine learning methods were introduced decades ago, the convergence of computation power, more data collection, and maturation of methods has led to an explosion in the types of problems machine learning can be applied to. A comparison of several common surrogate modeling techniques found that parametric radial basis functions and Kriging are highly accurate regression techniques for predicting building energy consumption. For a single climate, these regression techniques can predict the total energy consumption to within 2% of a detailed energy simulation, but in a fraction of a second, about five orders of magnitude faster. Integrating a Kriging surrogate model with multi-objective optimization, allowed for finding retrofit recommendations in Lisbon that are cost effective and can reduce the present-day energy consumption of an existing apartment by up to 20%. Similarly, integrating surrogate model with multi-objective optimization can find retrofit options in Boston that can reduce the present-day energy consumption and unmet hours in the future. Combined this body of works strives to add value to existing building energy performance simulation tools as more than just an exercise for code compliance but as a real design tool that can guide decision making.by Arfa Nawal Aijazi.S.M. in Building Technolog
Flexible exportation mechanisms of arthrofactin in Pseudomonas sp. MIS38
No full textAims: To obtain further insights into transportation mechanisms of a most effective biosurfactant, arthrofactin in Pseudomonas sp. MIS38. Methods and Results: A cluster genes arfA/B/C encodes an arthrofactin synthetase complex (ArfA/B/C). Downstream of the arfA/B/C lie genes encoding a putative periplasmic protein (ArfD, 362 aa) and a putative ATP-binding cassette transporter (ArfE, 651 aa), namely arfD and arfE, respectively. The arfA/B/C, arfD, and arfE form an operon suggesting their functional connection. Gene knockout mutants ArfD:Km, ArfE:Km, ArfD:Tc/ArfE:Km, and gene overexpression strains MIS38(pME6032_arfD/E) and ArfE:Km(pME6032_arfD/E) were prepared and analyzed for arthrofactin production profiles. It was found that the production levels of arthrofactin were temporally reduced in the mutants or increased in the gene overexpression strains, but they eventually became similar level to that of MIS38. Addition of ABC transporter inhibitors, glibenclamide and sodium ortho-vanadate dramatically reduced the production levels of arthrofactin. This excludes a possibility that arthrofactin is exported by diffusion with the aid of its own high surfactant activity. Conclusions: ArfD/E is not an exclusive but a primary exporter of arthrofactin during early growth stage. Reduction in the arthrofactin productivity of arfD and arfE knockout mutants was eventually rescued by another ABC transporter system. Effects of arfD and arfE overexpression were evident only for one-day cultivation. Multiple ATP dependent active transporter systems are responsible for the production of arthrofactin. Significance and impact of the study: Pseudomonas bacteria are characterized to be endued with multiple exporter and efflux systems for secondary metabolites including antibiotics, plant toxins, and biosurfactants. The present work demonstrates exceptionally flexible and highly controlled transportation mechanisms of a most effective lipopeptide biosurfactant, arthrofactin in Pseudomonas sp. MIS38. Because lipopeptide biosurfactants are known to enhance efficacy of bioactive compounds and arfA/B/C/D/E orthologous genes are also found in plant pathogenic P. fluorescens and P. syringae strains, the knowledge would also contribute to develop a technology controlling plant diseases
miRNA-Mediated KHSRP Silencing Rewires Distinct Post-transcriptional Programs during TGF-β-Induced Epithelial-to-Mesenchymal Transition
No full textSummaryEpithelial-to-mesenchymal transition (EMT) confers several traits to cancer cells that are required for malignant progression. Here, we report that miR-27b-3p-mediated silencing of the single-strand RNA binding protein KHSRP is required for transforming growth factor β (TGF-β)-induced EMT in mammary gland cells. Sustained KHSRP expression limits TGF-β-dependent induction of EMT factors and cell migration, whereas its knockdown in untreated cells mimics TGF-β-induced EMT. Genome-wide sequencing analyses revealed that KHSRP controls (1) levels of mature miR-192-5p, a microRNA that targets a group of EMT factors, and (2) alternative splicing of a cohort of pre-mRNAs related to cell adhesion and motility including Cd44 and Fgfr2. KHSRP belongs to a ribonucleoprotein complex that includes hnRNPA1, and the two proteins cooperate in promoting epithelial-type exon usage of select pre-mRNAs. Thus, TGF-β-induced KHSRP silencing is central in a pathway leading to gene-expression changes that contribute to the cellular changes linked to EMT
“Effectiveness” in Adaptive Reuse of Modern Heritage Buildings
No full textAdaptive reuse (AR) of modern buildings, including industrial buildings from the late 19th and 20th centuries, is a complex process as it involves many actions and actors, which influence the result of projects. Effective AR can provide many advantages for societies. This paper aims to provide an overview of the three most highlighted criteria, mentioned by previous researchers, for assessing effectiveness of AR of modern buildings.This research followed seven steps: 1.Reviewing the criteria of “effectiveness” in AR projects in the literature 2.Collecting the data (jury reports of NRP and Europa-Nostra awards) 3.Distilling the reports related to modern heritage buildings 4.Translation of Dutch reports in English 5.Analysing and coding the texts following the criteria mentioned in the literature 6.Analysing the role of effective AR of modern heritage buildings in providing sublimation and social value 7.Formulating some conclusions/recommendations.This review indicates despite the attribution of the effectiveness of AR of non-modern heritage buildings to the attraction of tourists, the effectiveness of AR in modern buildings is often attributed to positive effects on the surroundings and local community. Moreover, in modern buildings, compared to non-modern buildings, qualities provided by new interventions are highlighted more. This can be related to open space plans, stronger materials, wider spans, and spacious urban settings providing a higher tolerance for acceptable change.By revealing the aspects of effectiveness within these two criteria, this study contributes to the broader understanding of the AR potential of modern buildings. Though this review is useful for encouraging the reuse of modern buildings, the methods/tools to be used to achieve effective results need more investigation in future research.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Heritage & TechnologyHeritage & Desig
Polycystic ovary syndrome, subfertility and vitamin D deficiency
No full textPolycystic ovarian syndrome (PCOS) is the most common endocrine female disorder, affecting 4-18% women of reproductive age. The prevalence of PCOS in South Asian women, especially in Pakistani women, is much higher (52%) as compared to white population (20 - 25% in UK). In Pakistan, vitamin D status displays 31.2% vitamin D insufficiency, 53.5% vitamin D deficiency, and 15.3% normal vitamin D values. Vitamin D deficiency, though very common in the general population, is even more prevalent in PCOS patients, seen in approximately 67-85%, which further correlates to their related comorbidities. A lot of researches have to be directed to examine the association among the PCOS and vitamin D, which may display monitoring role in several symptoms related to PCOS, such as ovulatory dysfunction, endocrine disruption, and insulin resistance. Vitamin D supplementation can, therefore, be employed to improve the metabolic and endocrine disorders; especially improving hormonal profile, oxidative stress, and ovulation outcome in PCOS patients. Key Words: Vitamin D, Infertility, Ovulatory Dysfunction, Insulin Resistance
Adaptive Reuse of Heritage Buildings: From a Literature Review to a Model of Practice
No full textThe Adaptive Reuse (AR) of heritage buildings is a complex process, which aims to preserve the values of heritage buildings while adapting them for use in the present and transferring them to the future. This paper aims to identify steps in this process and develop a structured model. The model is an ‘ideal’, it needs validation in practice; however, it is expected that following this model can help to preserve and conserve the values of heritage buildings. To come to an overview of the process and to identify its main steps, a literature review at an international level has been conducted. The analysis of the literature revealed that the AR process as a whole in relation to heritage buildings has not been widely studied. Based on the results of this review, a conceptual model representing the AR process of heritage buildings has been defined. This model consists of 10 steps: ‘initiative’, ‘analysis of heritage buildings’, ‘value assessment, ‘mapping level of significance’, ‘definition of adaptive reuse potential’, ‘definition of design strategy’, ‘final decision-making’, ‘execution’, ‘maintenance’, and ‘evaluation after years’. This model can act as a comprehensive theoretical basis for further studies on the AR process of heritage buildings.Heritage & TechnologyHeritage & Desig
