39 research outputs found
Regulation of expression of copper responsive genes in Sulfolobus solfataricus:
No full textCopper is an essential micronutrient, but toxic in excess. Cells must maintain their internal level of copper within a narrow range of concentrations. This is accomplished mainly by copper efflux mediated by ATP-driven copper transporters that are induced at the level of transcription. Sulfolobus solfataricus has the ability to adapt to fluctuations of copper levels in its environment. Two Sulfolobus strains P2 and 98/2, showed different sensitivity to copper To better understand the molecular mechanism behind the organismal response to copper, the expression of the cluster of genes copRTA, which encodes the copper-responsive transcriptional regulator CopR, the copper-binding protein CopT, and CopA, has been investigated. The expression of the copR and copA transcripts was monitored by quantitative real-time RT-PCR. The data showed that only copA was induced by copper. By comparing the patterns of copA expression and cellular copper accumulation, as determined by Inductively Coupled Plasma Optical Emission spectrometry, it was concluded that the level of copA depends on the internal fluctuations of copper. To investigate the role of CopR, a mutant carrying a disruption of the copR gene was created. The mutant strain was uncapable of growth in the presence of excess copper, and under the same conditions no transcription of copA was observed. These data suggested that CopR positively regulates transcription of copA. The knockout mutant strain PBL2070, its parent strain and the mutant complemented with a wild type copy of copR, were compared with respect to their physiological and transcriptional response to copper. Results confirmed that, under copper stress, CopR, activates the transcription of copA, and its presence restores the wild type phenotype resistant to copper. Finally, a reporter system based on the thermostable β-glucuronidase of S. solfataricus was developed to study the promoter of regulated genes. This system was applied to the analysis of the copTA promoter region fused to the S. solfataricus β-glucuronidase reporter. GUS activity assays showed that after copper addition, the activity of GusB was consistent with the transcriptional changes observed for copA under similar conditions. The results provide the basis for a model of the molecular mechanisms of copper homeostasis in Sulfolobus.Ph.D.Includes bibliographical references (p. 87-113)by Aramis Alexis Villafañe Martine
Graviton–Thermodynamic Theory of Universal Emergence and Rebirth
No full textThis project explores a novel theoretical framework proposing that universe formation originates from a graviton-thermodynamic process triggered within supermassive black holes. It introduces the idea that gravitons, emerging from a primordial zero-state, catalyze thermodynamic transitions that lead to Big Bang–like events. The theory suggests an evolutionary model of universe reproduction governed by entropy, matter accumulation, and quantum conditions. All diagrams, equations, and concepts are original to the author, and the work is intended as a speculative but structured contribution to cosmology and quantum gravity discussions
Imprints in Dual Phase Hot Rolled Steel
No full textDP600 HR is one of Tata Steels hot rolled products. It is a dual phase steel unique to Tata Steel for its two step cooling process and low coiling temperature. The finished product has encountered several surface defects, one of which are imprints. In order to find the root cause for the imprints a literature study, a factory inspection and a number of experiments have been conducted. To find the origin of the imprint two coils have been produced with the intention to create imprints on the surface. With these trials and the observations in the factories within Tata Steel it is found that a loose oxide layer of 4-10µm thick is formed at the end of the hot strip mill process. Due to the low coiling temperature a fair amount of water remains on the strip until further processing. At both the recoiler and the pickling line a build-up of loose oxide is seen. From both former trials and the trials done during this project it is seen that a build-up of oxide leaves imprints with a depth of 20 to 150 µm. In order to confirm that the imprints can indeed be produced by loose oxides, two experiments were conducted. Loose oxide particles and bearing balls have been pressed into the steel surface with the result in both cases of imprints that can be compared to the ones obtained in the factory. In this work a new procedure has been developed to test the growth of the oxide layer as well as its adhesion to the steel surface. 1. To grow an oxide layer the Thermo Mechanical Testing Simulator is used. This device is normally used to test hot deformability of metals but its heating chamber can also simulating the run out table two step cooling cycle. Both cooling rates are varied between 30, 60 and 90 K=s keeping initial, intermediate and final temperatures equal to the factory values. 2. To test the adhesion of the oxide to the steel a tensile test is performed with the aid of the ARAMIS optical strain measuring system. Since the ARAMIS system follows optically the changes in the steel surface during straining the oxide layer is usually previously removed, because it will break first and interfere with the measurement. However this fact is used here to our advantage since the strain that is necessary to remove the layer can now be quantified. This loss in measurement data corresponds well to the initial loss of oxide from the sample. From the ARAMIS data it is seen that increasing the cooling rate of the first cooling step decreases the amount of strain required to break the oxide from the steel. The second cooling step does not have a pronounced effect on the adhesiveness. The microscopy analysis showed an unknown oxide layer at the steel/oxide interface. This layer is mainly iron oxide but contains an unusual amount of chromium. It is presently not known how the chromium is distributed in the oxide nor what its effects on the properties of the scale are. It is concluded that the imprints are caused by a build-up of loose oxide on the work rolls. The imprints can be prevented by not using the levelling and scale breaker work rolls. The adhesiveness of the oxide to the steel under deformation can be improved by reducing the cooling rate on the first cooling step. Using the Thermo Mechanical Test Simulator a controlled layer of oxide can be grown on steel samples. The adhesiveness of the oxide layer can then be tested by means of a tensile test while being recorded by ARAMIS. This set-up can be further improved to obtain a standardised oxide adherence testing method.Aerospace EngineeringAerospace Structures and Material
Strain distribution in asphalt mixtures during the wheel tracking test at high temperatures
No full textIn general rutting in asphalt pavements occurs at high temperatures and cracks occur at cold temperatures. It has been believed that longitudinal cracks mainly arise due to the shear of moving wheels at high temperatures. This research performed wheel tracking tests at 45 C on asphalt samples in holders which at one end consists of transparent glass. The distribution of the tensile and shear strains using the ARAMIS System for gathering data of the exposed end (30 5 cm) of the specimens visible through the transparent glass was measured. Thereafter, specimens (5 8 2.5 cm) cut from large specimen (5 30 30 cm) for CT scanner. The width of crack was also analyzed by CT scanner in three dimensional. It was found that the rutting depth in all specimens after 1 h (2400 wheel passes) at 45 C was smaller than 1 mm, but that the tensile strains in all specimens at 1 hour were 25,000 10 6 (2.5%) or larger and a strain of 3.69% which corresponds to a longitudinal crack width of 0.555 mm by CT analysis and ARAMIS system. It was also found that the cracks at the high temperature under the moving wheels were mainly caused by the tensile strain rather than shear strain and the load spreadability in mixtures depends upon the type of mixture and properties of asphalt. It is concluded that both methods are useful to evaluate the damage of mixture
Los reflejos de la sociedad: intentar comprender la paradoja de "salud mental"
No full textIn his book Normality, psychic conflict, social control. Society, mental health, and illness, Enrique Guinsberg questions the definition of mental health. While some institutes and specialized organizations propose a broad understanding that encompasses psychological, physical, and social well-being, Guinsberg argues that this proposal is idealized and does not reflect the complexity of real life. The author discusses the impact that disturbances in physical health, poverty, and psychological problems have on mental health. Additionally, he analyzes how throughout history, the terms "normality" and "madness" have been used to perpetuate power structures, and he reflects on the relevance of professionals and institutions in this particular context.En su libro Normalidad, conflicto psíquico, control social. Sociedad, salud y enfermedad mental, Enrique Guinsberg cuestiona la definición de salud mental. Aunque socialmente, algunos institutos y organismos especializados proponen un entendimiento amplio que abarca el bienestar psíquico, físico y social, Guinsberg planeta que esta propuesta es idealizada y no refleja la complejidad de la vida real. El autor expone el impacto que perturbaciones en la salud física, la pobreza y problemas psicológicos, tiene en la salud mental, además analiza la forma en la que a lo largo de la historia, los términos "normalidad" y "locura" se han empleado para perpetuar estructuras de poder y reflexiona en torno a la relevancia de los profesionales y las instituciones en este contexto particular
Spécialisation trophique et premiers états chez les Cymothoe : implications taxonomiques (Lepidoptera, Nymphalidae)
No full textThe systematics of Cymothoe feeding on Rinorea can be improved by the knowledge of the early stages and host-plants. The author presents three examples taken in the cameroonian fauna :
- "yellow" and "red" forms of C. aramis and C. distincta, - the discovery of unknown sibling species of C. egesta, - the existence of a C. sangaris complex of at least four species in Cameroon. The limits of the method are thrown into light and the notion of "sibling species" in entomology is questionned.Chez les Cymothoe qui se nourrissent de Rinorea, la connaissance des premiers états et des plantes-hôtes peut contribuer à améliorer la systématique spécifique. L'auteur développe trois exemples empruntés à la faune camerounaise : - formes "orange" et "rouge" chez C. aramis et C. distincta, - existence d'"espèces jumelles" insoupçonnées chez C. egesta, - complexe de C. sangaris (au moins quatre espèces au Cameroun). Les limites de la méthode sont soulignées et la notion d'espèce "jumelle" en entomologie est brièvement discutée.Amiet Jean-Louis. Spécialisation trophique et premiers états chez les Cymothoe : implications taxonomiques (Lepidoptera, Nymphalidae). In: Bulletin de la Société entomologique de France, volume 102 (1), mars 1997. pp. 15-29
Correction: Overall survival and adverse events after treatment with darolutamide vs. apalutamide vs. enzalutamide for high-risk non-metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis (Prostate Cancer and Prostatic Diseases, (2022), 25, 2, (139-148), 10.1038/s41391-021-00395-4)
No full textCorrection to: Prostate Cancer and Prostatic Diseases, published online 30 May 2021 The author wants to make the following corrections: Table 1: “The proportion of N1 (control vs. treatment) ... 29% vs. 17%” Text pages 140–141: “Patients with regional lymph node metastases were only allowed in the SPARTAN and ARAMIS trials and their proportions differed (Table 1). In the SPARTAN trial 16 and 16% harbored regional lymph node metastases, in respective control and treatment arms vs. 29 and 17% respectively in the ARAMIS trial.” Table 1: “The proportion of N1 (control vs. treatment) ... 12% vs. 10%” Text pages 140–141: “Patients with regional lymph node metastases were only allowed in the SPARTAN and ARAMIS trials and their proportions differed (Table 1). In the SPARTAN trial 16 and 16% harbored regional lymph node metastases, in respective control and treatment arms vs. 12 and 10% respectively in the ARAMIS trial.” Text pages 145–146: “However, more pronounced differences were recorded in rates of regional lymph node metastases and the study findings need to be interpreted in their light. However, it should also be noted that the distribution of lymph node metastases was virtually the same in the treatment and control arms in the SPARTAN and PROSPER trials. Although the distribution of lymph node metastases was unequally divided in the ARAMIS trial (control: 29 vs. treatment: 17%), a higher prevalence of lymph node metastases in the control arm certainly did not prevent darolutamide from ranking first in overall efficacy analyses. In consequence, it is not clearly evident that lymph node metastases rate differences resulted in important heterogeneity that confounded the study findings.” “Differences in patient characteristics that exist between the three-phase III RCTs are also important to consider in the interpretation of the current, as well as all previous NMAs. Very similar distribution of PSA, PSA-DT, baseline Gleason scores and regional lymph node metastases most likely had marginal if any contribution to population heterogeneity, within the three- phase III RCTs. However, study designs differed with respect to PSA- DT definitions. Specifically, the PROSPER trial relied on PSA-DT of less than 6 months. Conversely, the SPARTAN and ARAMIS trials included patients with PSA-DT for up to six months. Such difference may be marginal. However, it requires mention. In addition, all studies relied on conventional imaging. Although the use of conventional imaging did not differ between studies, it is of importance to emphasize that patient inclusion in the category of high-risk nmCRPC was much higher than if PSMA PET/CT was systematically obtained. Moreover, the timing of AE capture and their definitions may have also demonstrated small, albeit potentially important differences that influenced AE rates of the three ARATs. However, it is unlikely that study design differences have induced important confounding variables that prevent valid direct or indirect comparisons between the three RCTs since the endpoint of interest corresponds to OS. In all three RCTs, the assessment of this endpoint is the same. In addition, differences with respect to patterns of PSA-progression-free survival and metastatic progression-free survival (Supplemental Fig. 2) exist between the three RCTs. All of the above potential differences, regardless of their marginal or more important magnitude, were not and could not be formally addressed or adjusted for within the NMA methodology.” The original article has been corrected
Spécialisation trophique et premiers états chez les Cymothoe : implications taxonomiques (Lepidoptera, Nymphalidae)
No full textThe systematics of Cymothoe feeding on Rinorea can be improved by the knowledge of the early stages and host-plants. The author presents three examples taken in the cameroonian fauna :
- "yellow" and "red" forms of C. aramis and C. distincta, - the discovery of unknown sibling species of C. egesta, - the existence of a C. sangaris complex of at least four species in Cameroon. The limits of the method are thrown into light and the notion of "sibling species" in entomology is questionned.Chez les Cymothoe qui se nourrissent de Rinorea, la connaissance des premiers états et des plantes-hôtes peut contribuer à améliorer la systématique spécifique. L'auteur développe trois exemples empruntés à la faune camerounaise : - formes "orange" et "rouge" chez C. aramis et C. distincta, - existence d'"espèces jumelles" insoupçonnées chez C. egesta, - complexe de C. sangaris (au moins quatre espèces au Cameroun). Les limites de la méthode sont soulignées et la notion d'espèce "jumelle" en entomologie est brièvement discutée.Amiet Jean-Louis. Spécialisation trophique et premiers états chez les Cymothoe : implications taxonomiques (Lepidoptera, Nymphalidae). In: Bulletin de la Société entomologique de France, volume 102 (1), mars 1997. pp. 15-29
Effect of Foam’s Heterogeneity on the Behaviour of Sandwich Panels
No full textThis study aimed to develop a knowledge about material parameters identification of the foam core and numerical modelling of the sandwich panels to accurately predict the behaviour of this kind of structures. The polyisocyanurate foam (PIR) with low density used in sandwich panels dedicated to civil engineering is examined in the paper. A series of experiments (tensile, compression and bending tests) were carried out to identify its mechanical parameters. To determine the heterogeneity of analysed foam a Digital Image Correlation (DIC) technique, named Aramis, is applied in the paper. The results obtained from FE analyses are compared with the experimental results on full-size plates carried out by the author and proper conclusions are drawn
