Transgenic rodents carrying reporter genes to detect organ‐specific in vivo genetic alterations are useful for risk assessment of genotoxicity that causes cancer. Thus, the Organization for Economic ...Co‐operation and Development has established the guideline for genotoxicity tests using transgenic animals, which may be combined with repeated‐dose toxicity studies. Here, we provide evidence to support equivalence of gpt delta and wild type (WT) rats in terms of toxicological responses to a genotoxic hepatocarcinogen, N‐nitrosodiethylamine (DEN), and a non‐genotoxic hepatocarcinogen, di(2‐ethylhexyl)phthalate (DEHP). gpt delta rats treated with DEHP showed similar increases in liver and kidney weights, serum albumin, albumin/globulin ratios, and incidence of diffuse hepatocyte hypertrophy compared to WT F344 and Sprague–Dawley (SD) rats. DEN‐treated gpt delta rats showed equivalent increases in the number and area of precancerous GST‐P‐positive foci in the liver compared to WT rats. The livers of DEN‐treated gpt delta rats also showed increased frequencies of gpt and Spi− mutations; such changes were not observed in DEHP‐treated gpt delta rats. These results indicated that gpt delta rats (both F344 and SD backgrounds) showed comparable DEHP‐induced toxicity and DEN‐induced genotoxicity to those observed in WT rats. With regard to the administration period, the general toxicity of 1.2% DEHP was evident throughout the experimental period, and the genotoxicity of 10 p.p.m. DEN could be detected after 2 weeks of administration and further increased at 4 weeks. These results suggested that combined assays using gpt delta rats could detect both general toxicity and genotoxicity by the canonical 4‐week administration protocol. Therefore, this assay using gpt delta rats would be applicable for risk assessment including early detection of genotoxic carcinogens and ultimately serve to reduce cancer risks in humans from environmental chemicals.
To support development of a combined assay for general toxicity and genotoxicty by using transgenic rodents, we provide evidences that indicate equivalence of gpt delta rats, which carry reporter genes to detect in vivo genotoxicity, to their parental wild type in terms of toxicological responses. DEN‐ or DEHP‐ treated F344 and SD strains of gpt delta rats display comparable general toxicity and genotoxicity to wild type. Our results indicate that the combined assay using gpt delta rats was applicable for simultaneous detection of both general toxicity and genotoxicity for short durations of administration.
This study investigated differences in gluten aggregation time and gluten strength using the Hofmeister series in high shear-treated slurries. Two flours (15.1% and 10.6% protein) were evaluated by ...using a Gluten Peak Tester (GPT). Hofmeister anions including NaF, NaCl, NaBr, NaI, and NaSCN at concentrations ranging from 0.1 to 1.0
M and cations including KCl, NaCl, NH
4Cl, MgCl
2, and CaCl
2 at concentrations ranging from 0.0625 to 1.0
M were used. The instrument applies high shear to a flour/salt solution slurry and measures torque and aggregation time to form gluten. Aggregation time using the GPT followed the order of the Hofmeister series, with minor effects at salt concentration <
0.3
M and increasing differences at higher salt concentrations. Torque increased with increasing concentration. Creating models of the trends using second and third order equations demonstrated that gluten aggregation follows a distinct natural law in the slurries. The study confirmed the potential of the high shear based method to be used a research tool to investigate gluten aggregation properties and to potentially predict functionality in baked product systems.
Nitrofurans are antimicrobial compounds containing a nitro group at the 5-position of the furan ring and an amine or hydrazide side chain derivative. One member of the nitrofurans, nitrofurantoin ...(NFT), is a renal carcinogen in male rats despite its still controversial genotoxicity. We investigated chemical structure-related modes of action of NFT, and reporter gene mutation assays for NFT and its constituent moieties were performed. NFT, 5-nitro-2-furaldehyde (NFA), or 1-aminohydantoin (AHD) was administered to male F344 gpt delta rats by gavage for 4 or 13 weeks at a carcinogenic or the maximum tolerated dose. NFT caused a significant increase in gpt mutant frequency (MF) at 13 weeks with G-base substitution mutations. An increase in gpt MF was also observed in the NFA-treated group at 13 weeks, but not in the AHD-treated group. 8-Hydroxydeoxyguanosine (8-OHdG) levels in the kidney DNA of NFT-treated rats were significantly increased after 4 weeks. NFT caused accumulation of hyaline droplets indicated by positive immunostaining and western blot analysis for α2u-globulin in the proximal tubules. An additional study, in which female gpt delta rats were given NFT at the same dose used for males, was performed to mitigate the effect of α2u-globulin. NFT exerted the same effects on female rat kidneys to the same extent as males in terms of gpt MF and 8-OHdG level. Thus, it is highly probable that the structure of the nitro furan plays a key role in NFT-induced genotoxicity and genotoxic mechanisms including oxidative DNA damage are involved in NFT-induced renal carcinogenesis. α2u-globulin-mediated nephropathy may be a prerequisite for NFT-induced renal carcinogenesis in male rats, and additionally NFT could be a latent carcinogen in female rats and other animal species.
El ejecutivo eficaz Calderón Valdés, Juan José
Revista gestión de las personas y tecnología,
2014
20
Journal Article
Recenzirano
Odprti dostop
El libro seleccionado para esta reseña se llama “El Ejecutivo Eficaz” del autor Peter F. Drucker, libro originalmente escrito en inglés llamado “The effective executive”, con su primera edición ...lanzada en EE.UU. durante el año 1967. Calificado como Best Seller, esta versión fue traducida al español por Horacio Laurora (Argentino) para su primera edición hecha en 2014 por la editorial Argentina “Debolsillo” en formato Ebook (versión electrónica para dispositivos Apple).
El Ministerio de Educación solicitó a la Academia Chilena de Ciencias un estudio, basado en experiencias reales, acerca de la situación actual en Chile en materia de innovación, ciencia y tecnología. ...La Academia formuló un proyecto, y puso a su cargo a un equipo de cuatro académicos: Juan Asenjo, Tomás Cooper, Fernando Lund y Bernabé Santelices. El libro es el producto final del proyecto. Estos académicos fueron quienes se encargaron de la edición del libro.
En diciembre de 1914 se da inicio a una de las historias de sobrevivencia más connotadas en la historia de Gran Bretaña, la “British Trans-Antartic Expedition”, liderada por Sir Ernest Shackleton, ...con un objetivo claro pero ambicioso, lograr el primer cruce del continente antártico. Si bien Shackleton conocía los riesgos que involucraba esta travesía, no fue sino hasta que su barco, el “Endurance”, se hunde prisionero en el hielo, es entonces que se da cuenta que el real enemigo de esta expedición no era el hielo, sino que mantener la moral de su tripulación en alto.
In our study, we propose an automated high-quality quiz generation system by integrating the use of Large Language Models (LLM) with RAG (Retrieval-Augmented Generation) and Self-Refine mechanisms. ...RAG collects relevant information from external databases such as Wikipedia and utilizes this as prompts for the GPT model. On the other hand, the Self-Refine mechanism generates feedback using LLM for the initially produced quizzes and iteratively refines the quizzes based on this feedback. The primary goal of this system is to efficiently generate quizzes with high accuracy and relevance, and the results have been validated through evaluations by people. Experimental results have shown that the Self-Refine mechanism significantly improves the initial quiz generation process, enabling the creation of high-quality quizzes.
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