58 research outputs found

    Fresh and hardened properties of concrete incorporating binary blend of metakaolin and ground granulated blast furnace slag as supplementary cementitious material

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    The growing demand for cement has created a significant impact on the environment. Cement production requires huge energy consumptions; however, Pakistan is currently facing a severe energy crisis. Researchers are therefore engaged with the introduction of agricultural/industrial waste materials with cementitious properties to reduce not only cement production but also energy consumption, as well as helping protect the environment. +is research aims to investigate the influence of binary cementitious material (BCM) on fresh and hardened concrete mixes prepared with metakaolin (MK) and ground granulated blast furnace slag (GGBFS) as a partial replacement of cement. +e replacement proportions of BCM used were 0%, 5%, 10%, 15%, and 20% by weight of cement. A total of five mixes were prepared with 1 :1.5 : 3 mix proportion at 0.54 water-cement ratios. A total of 255 concrete specimens were prepared to investigate the compressive, tensile, and flexural strength of concrete after 7, 28, and 56 days, respectively. It was perceived that the workability of concrete mixes decreased with an increasing percentage of MK and GGBFS. Also, the density and permeability of concrete decreased with an increasing quantity of BCM after 28 days. Conversely, the compressive, tensile, and flexural strength of concrete were enhanced by 12.28%, 9.33%, and 9.93%, respectively, at 10% of BCM after 28 days. +e carbonation depth reduced with a rise in content of BCM (up to 10%) and then later improved after 28, 90, and 180 days. Moreover, the effect of chloride attack in concrete is reduced with the inclusion of BCM after 28 and 90 days. Similarly, the drying shrinkage of concrete decreased with an increase in the content of BCM after 40 days

    A review of the engineering properties of metakaolin based concrete: towards combatting chloride attack in coastal/ marine structures

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    Changing human lifestyle and increasing urbanisation are contributory factors to the high demand for concrete construction materials across the globe. With the imminent developments in the unpopulated marine/coastal zones, higher installation of concrete facilities is still expected. However, poor design and construction procedures coupled with inadequate materials selection and exposure to aggressive environmental conditions, such as chloride laden environments, often result in the reduced aesthetic and structural performance of concrete. Deterioration of reinforced concrete structures located in a coastal/marine setting can influence the safety, economic, and sustainability aspects of society. Hence, there is an increased need for alternate binder systems with the ability to reduce the effects of chloride attack in concrete. 1is paper presents a critical review of the engineering properties of metakaolin (MK) based concrete exposed to chloride attack. 1e key advantages and limitations of using MK for concrete production purposes were outlined and evaluated. Areas for future research were also highlighted in this paper. Based on the favourable 28-day compressive strength (73–84 MPa) and durability performance documented across the numerous past year studies that were reviewed, it can be concluded that MK is a viable alternate binder material for combatting chloride attack in coastal/marine concrete structures. 1is, in conjunction with its lack of chemical CO2 emissions, proves that MK can be used to improve the serviceability and sustainability states of marine structures. 1e viewpoint of this review will guide concrete constructors and researchers on a possible framework for the utilisation of metakaolin for enhancing durability concrete in aggressive environments

    Organizing health care: an ethical perspective

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    Indexación: Web of Science; Scielo.Health Care at population level is a complex problem. Having this in mind, the purpose of this paper is to focus on the goods that are ethically relevant in the process of caring for health at this level. We briefly analyze some of the Chilean health statistics that, although they show important improvements along the years, demonstrate that certain conditions are to be deemed as inadequate by both healthcare providers and patients. Ethics is a central component to determine how to structure and organize health care systems and how they should operate. We emphasize Human Dignity as an ethical corner stone of the Health Care System, along with other important values such as Justice and Humanization, under the scope of the Ends of Medicine, and other components such as technical competence of providers and the financing of the whole process. We conclude that as far as a health care system is organized in a way that medical practice is well ordered, primarily and fundamentally according the Ends of Medicine and the good of persons, such a health care system is ethically adequate.http://ref.scielo.org/9bt3z

    Algunas amenazas actuales a la confidencialidad en medicina

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    Social, technical and legal conditions of the current practice of medicine make it necessary to insist on certain actions and circumstances that may jeopardize the confidentiality of information, offered by patients to their health providers. Therefore, some effects of the current Chilean law are analyzed in this respect, regarding access to data from the clinical record of a patient. Also, the risks of putting certain data on social networking sites are analyzed, as well as some of its effects on clinical practice. The reasons because of mandatory reporting of diseases, meaning danger to public health, is allowed, are mentioned. We also discuss the difficulties involved in managing the results of preventative health screenings and its knowledge by third parties, as well as some possible violations of personal privacy, regarding dissemination of some people health information and its further mention or figuration in mass media. We conclude that it is a must for both physicians and other health team members, to safeguard confidentiality of data to which they have had access, as well as the need to know the relevant law, in order to respect human dignity of patients, each one as a person. We address the attention to the possibility that, practicing in a different way, it could endanger the reliability of clinical records, also impairing the quality of people’s health care. (Rev Med Chile 2015; 143: 358-366) Key words: Access to Information; Confidentiality; Information Dissemination; Medical Records; Social Networkin

    Respecting patient intimacy

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    Indexación: Web of Science; Scielo.Transparency as a general rule for all our professional acts casts doubts about the statement of the Hippocratic Oath that says "Whatever I see or hear in the lives of my patients, I will keep secret, as considering all such things to be private". Medical secrecy protects the intimacy of patients, who reveal to their physicians their most hidden secrets aiming to recover their health. Therefore, physicians should receive those secrets with reverence and care, as servers and not as their owners. The values associated with the respect for personal intimacy are the anthropological basis of medical confidentiality. A medical act is performed by definition between two equally honorable individuals. Therefore, the professional honors the trust of his patient, maintaining strict confidence of what is revealed. Therefore, medical secrecy must be strengthened rather than weakened, pursuing common wealth and dignity.http://ref.scielo.org/cf3mx

    An ethical and medical perspective on the voluntary termination of pregnancy

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    Indexación: Web of Science; Scielo.“Voluntary termination of pregnancy” can refer to actions intended to make a delivery easier, to provide medical care to the fetus, or to protect the life or health of the mother. All of these are proper medical actions and are by definition voluntary. In other cases, the expression denotes a termination of pregnancy before the embryo or fetus is viable, leading to the death of the latter. This action is constitutive of abortion under current Chilean law. The product of conception living being, who develops in the womb during pregnancy, is an individual, both in the sense that it is different from its mother and father, and in that it is a biological individual. For these reasons, such living being constitutes another patient in itself. The free and voluntary medical action of health care professionals is geared toward disease prevention or health recovery and medical terminations of pregnancy, as distinguished from abortion, are not criminalized in our country. Therefore, the idea of legalizing abortive terminations of pregnancy so that they become “legitimate health care services” is a call to the medical community, which should engage in a debate about the meaning and consequences of an eventual mandate of the State that would be at odds with the Hippocratic tradition. A woman can feel that her health is at risk due to her pregnancy, and she certainly has the right to request medical help. Health professionals should care both at the medical and emotional level for all those who require their services, especially when such persons are undergoing situations of vulnerability and distress. When requested to perform an abortion, the physician faces dilemmas that should be addressed in line with the present state of the medical art.http://ref.scielo.org/c4ypf

    Vitamins as Active Agents for Highly Emissive and Stable Nanostructured Halide Perovskite Inks and 3D Composites Fabricated by Additive Manufacturing

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    The use of non-toxic and low-cost vitamins like α-tocopherol (α-TCP, vitamin E) to improve the photophysical properties and stability of perovskite nanocrystals (PNCs), through post-synthetic ligand surface passivation, is demonstrated for the first time. Especially interesting is its effect on CsPbI3 the most unstable inorganic PNC. Adding α-TCP produces that the photoluminescence quantum yield (PLQY) of freshly prepared and aged PNCs achieves values of ≈98% and 100%, respectively. After storing 2 months under ambient air and 60% relative humidity, PLQY is maintained at 85% and 67%, respectively. α-TCP restores the PL features of aged CsPbI3 PNCs, and mediates the radiative recombination channels by reducing surface defects. In addition, the combination of α-TCP and PNCs facilitates the chemical formulation to prepare PNCs-acrylic polymer composites processable by additive manufacturing. This enables the development of complex shaped parts with improved luminescent features and long-term stability for 4 months, which is not possible for non-modified PNCs. A PLQY ≈92% is reached in the 3D printed polymer/PNC composite, the highest value obtained for a red-emitting composite solid until now as far as it is known. The passivation shell provided by α-TCP makes that PNCs inks do not suffer any degradation process avoiding the contact with the environment and preserve their properties after reacting with polar monomers during composite polymerization.Funding for open access charge: CRUE-Universitat Jaume IThis work was supported by European Research Council (ERC) via Consolidator Grant (724424–No-LIMIT), Spanish Ministry of Science and Innovation under projects STABLE (PID2019-107314RB-I00) and NIRVANA (PID2020-119628RB-C33), Generalitat Valenciana via Prometeo Grant Q-Solutions (CIPROM/2021/078) and CIDEGENT (2018/036); and the Agencia Valenciana de Innovación (AVI) (INNCON/2021/13, INNVA/2022/9). M.Z. thanks Marie Skłodowska-Curie Individual Fellowships (GA no. 101026335) for funding. The authors also thank to Ministry of Education, Youth and Sports of the Czech Republic for the financial support of XPS measurements using CEMNAT infrastructure (project LM 2018103). The authors are very grateful to the “Serveis Centrals d'Instrumentació Científica (SCIC)” of the Universitat Jaume I

    Diagnóstico de Muerte

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    Industrialized Sunspace Prototype with Solar Heat Storage. Assessment of Post-Occupational Behaviour in Adaptive Facades.

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    The thermal performance of two passive solar components has been investigated. An attached sunspace with horizontal heat storage and another one with vertical thermal storage were designed in order to optimize the use of solar gains and its storage and distribution in an industrialized component. These sunspaces have been tested under real conditions, comparing their thermal performance with two commonly used components in residential buildings in Spain: a window and a double window making up an attached sunspace. Different series of experimental measurements were conducted in two test-cells exposed to outdoor conditions in Pamplona (Northern Spain). As a result, nine scenarios during winter 2011 and six during summer 2012 have been carried out, comparing all of the prototypes two by two with different use modes. Results show that a sunspace with heat storage takes advantage of the solar energy and improves the indoor thermal performance of the adjacent room during winter in a better way than a window or a simple sunspace, and that it also offers better performance in summer. The best results in winter and summer were obtained when an appropriate use of the component was performed, in concordance with outdoor conditions. Several thermal control keys for the use of these components are suggested

    Protein and lipid kinase inhibitors as targeted anticancer agents of the Ras/Raf/MEK and PI3K/PKB pathways

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    The identification and characterization of the components of individual signal transduction cascades, and advances in our understanding on how these biological signals are integrated in cancer initiation and progression, have provided new strategies for therapeutic intervention in solid tumors and hematological malignancies. To this end, pharmaceutical efforts have been directed to target different components of the Ras/Raf/MEK and PI3K/PKB pathways. This review article covers recent salient achievements in the identification and development of Raf, MEK, and PI3K inhibitors
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