Diseño de 1600 ML de adoquinado, ubicado en los barrios: anexo a la villa Victoria de julio, Antonio Mendoza y Rubén Ulloa; en el casco urbano de Tipitapa, municipio de Managua

El desarrollo de nuestro país se basa en elementos fundamentales, como: agricultura industria, ganadería, comercio, turismo, etc. Pero el factor determinante entre estos es el sistema nacional de transporte es decir: transporte terrestre, transporte aéreo, transporte marítimo, etc. el cual es el enlace principal para el desarrollo de la sociedad. En Nicaragua el transporte terrestre es el más utilizado por la población, y debido al aumento de la movilización de vehículos con motores más potentes por las vías, obliga a la modernización de la infraestructura vial, permitiendo un tránsito más seguro y eficiente. El incremento de la red vial está vinculado directamente con la economía de nuestro país, pues su papel es primordial en las actividades que se realizan a diario en los diferentes sectores que aportan a la economía nacional. Actualmente la construcción de nuevas vías de comunicación, rehabilitación de carreteras y mejoras de los caminos ya existentes debe ser una necesidad para los gobiernos, ya que constituyen un componente fundamental para el bienestar y desarrollo de la sociedad, además su diseño debe adoptar las condiciones necesarias para obtener una obra de calidad; cumpliéndose en el todos los principios y normas correspondientes al diseño de carreteras. El presente trabajo denominado ‘‘Diseño de 1600 ML de calle, ubicados en los barrios: Anexo la Villa Rubén Ulloa, Villa Victoria de Julio y Antonio Mendoza localizados en el casco urbano de Tipitapa, municipio de Managua’’. Muestra en su contenido los estudios, métodos y normas aplicables para elaborar: el diseño geométrico de la vía, diseño hidráulico y de la estructura de pavimento, tomando en cuenta las especificaciones correspondientes al diseño de carreteras en Nicaragua

When Noble Metal is Not Noble

"Noble metals are generally considered chemically inert in moist air. However, Rh (Rhodium) nanoparticles frequently have been studied and used as highly active catalysts for purification of automobile and industry exhaust. Being one of the most expensive noble metals (its market price is twice as much as gold), it is important to obtain good catalytic efficiency per Rh unit weight. In order to understand the reaction mechanism at an atomic level and improve the Rh catalytic activity, my research has been focused on model catalysts study of Rh clusters and nanoparticles supported on planar surfaces. In the image presented, we successfully prepared hexagonal islands of Rh nanoparticles with narrow size distribution. We were able to use Rh(CO)2(acac) as a precursor, which is more efficient by means of cost. The organic ligands can help to stabilize the Rh particles from sintering upon heating and maintain the catalytic activity. By gradually heating the sample and removing the ligands, the size and shape of Rh nanoparticles changes can be observed by a Scanning Tunneling Microscope. This allows us to understand the relationship between the reactivates and the Rh nanoparticles size and shape changes.

Reactivity for the Diels–Alder Reaction of Cumulenes: A Distortion-Interaction Analysis along the Reaction Pathway

Cumulenes, including allene, ketenimine, and ketene, can be employed as dienophiles in Diels–Alder type reactions. The activation energies of a Diels–Alder reaction between cyclopentadiene and either the CC bond or the other CX (X = C, N, or O) bond in cumulenes have been calculated by G3B3, CBS-QB3, M06-2X, and B3LYP methods. The reactivity trend for the CC bond in cumulenes is allene > ketenimine > ketene and that of the CX bond in cumulenes is ketene > allene > ketenimine. Application of distortion-interaction analysis only at transition states does not give a satisfactory explanation for these reactivities. By employing distortion-interaction analysis along reaction pathways, we found that the reactivity of the CC and CX bond in cumulenes is controlled by both of its distortion and interaction energies. The lowest distortion energy of allene leads to its highest reactivity; the higher interaction energy results in higher activation energy of ketene than that of ketenimine. Compared with the reactivity of the CX bond in cumulenes, the CO bond in ketene has the lowest activation energy to react with cyclopentadiene, due to its lowest interaction energy, whereas the lower distortion energy of ketenimine than that of allene leads to a higher reactivity. The distortion energy of the reactants can be attributed to folding ability and molecule strain. The corresponding interaction energy of the reactants is controlled by orbital interaction, closed-shell repulsion, and static repulsion

PPh₃‑Catalyzed [3 + 2] Spiroannulation of 1<i>C</i>,3<i>N</i>‑Bisnucleophiles Derived from Secondary β‑Ketoamides with δ‑Acetoxy Allenoate: A Route to Functionalized Spiro <i>N</i>‑Heterocyclic Derivatives

A [3 + 2] annulation of α-substituted secondary β-ketoamides with δ-acetoxy-modified allenoate has been developed in the presence of phosphine catalyst. In this spiroannulation reaction, β-ketoamides were used as the bis-nucleophilic partner while the <i>γ,δ</i>-carbon of 5-acetoxypenta-2,3-dienoate participated as a C2 synthon, affording the desired functionalized five-membered <i>N</i>-heterocyclic derivatives in moderate to excellent yields and diastereoselectivities under mild conditions. Preliminary attempts on the asymmetric variant of this reaction have been also examined, giving the corresponding products with moderate ee values

PPh₃‑Catalyzed [3 + 2] Spiroannulation of 1<i>C</i>,3<i>N</i>‑Bisnucleophiles Derived from Secondary β‑Ketoamides with δ‑Acetoxy Allenoate: A Route to Functionalized Spiro <i>N</i>‑Heterocyclic Derivatives

A [3 + 2] annulation of α-substituted secondary β-ketoamides with δ-acetoxy-modified allenoate has been developed in the presence of phosphine catalyst. In this spiroannulation reaction, β-ketoamides were used as the bis-nucleophilic partner while the <i>γ,δ</i>-carbon of 5-acetoxypenta-2,3-dienoate participated as a C2 synthon, affording the desired functionalized five-membered <i>N</i>-heterocyclic derivatives in moderate to excellent yields and diastereoselectivities under mild conditions. Preliminary attempts on the asymmetric variant of this reaction have been also examined, giving the corresponding products with moderate ee values

Fabrication of Adjustable Au/Carbon Hybrid Nanozymes with Photothermally Enhanced Peroxidase Activity and Ultra-sensitivity for Glutathione Detection

Au nanozymes are extensively researched for their photothermal effect and catalytic performance, but overcoming the inherent defects of poor dispersibility and thermal stability through complementary materials will expand their prospects for biological applications. Herein, several novel CAu nanozymes were fabricated by in situ reduction of chloroauric acid on hollow carbon nanospheres (HCNs). Through regulating the number of reductions, sesame ball-shaped CAu (sCAu) with highly dispersed Au nanoparticles and diversity-shaped CAu (dCAu) were obtained. The number and morphology of loaded Au nanoparticles, absorption spectra, and hydrophilicity of CAu nanozymes were systematically characterized to demonstrate the flexibility of this novel method. The high-efficiency peroxidase-like sCAu0.3 nanozyme with hyperthermia-activated property was then screened for later bio-application. It is worth mentioning that its photothermal-promoted peroxidase-like activity could be achieved under near-infrared laser irradiation. Moreover, sCAu0.3 could specifically achieve glutathione detection in human blood samples. This method will provide a protocol for the regulation of CAu nanozymes to adapt to bio-detection applications

Unique Effects of the Chain Lengths and Anions of Tetra-alkylammonium Salts on Quenching Pyrene Excimer

Pyrene (Py) excimer, through its unique fluorescence quenching, exhibits high sensitivity and high selectivity in detecting specific electron-deficient molecules, providing a potential platform for sensing technology, optical switch, and probing hydrophobicity of molecular environment. In solution state, its quenching mechanism has been well-studied. However, there remain many unknown properties regarding the quenching mechanism of the solid-state Py excimer. In this paper, the effects of a series of tetra-alkylammonium salts (with a variety of chain lengths and anions) on Py excimer quenching are investigated to identify the controlling parameters of the fluorescence quenching in the binary system. Several experimental approaches including steady-state fluorescence spectroscopy, UV absorption, ¹³C-nuclear magnetic resonance (NMR) spectra, X-ray diffraction, scanning electron microscopy, and time-dependent fluorescence decay are employed to seek for the fundamental understanding of the quenching mechanism. The result indicates a unique quenching effect of tetrabutylammonium cation on the pyrene excimer, and which is not observed in the other cations with different chain lengths (the same associated hexafluorophosphate anions). Meanwhile, hexafluorophosphate anion (in the presence of tetrabutylammonium) is able to effectively retain Py excimer fluorescence when the system is prepared by evaporating solvent at high temperature. It is also confirmed that dynamic quenching is involved in the process. Hydrophobic environment around Py molecules shows strong correlation with the formation of Py excimer. The knowledge obtained in this study provides the insights to how the interaction between salt and Py molecule affects the excimer fluorescence

Controllable Formation of Pyrene (C₁₆H₁₀) Excimers in Polystyrene/Tetrabutylammonium Hexafluorophosphate Films through Solvent Vapor and Temperature Annealing

Pyrene, because of its wide applications in fluorescence sensors, has been studied extensively. Nevertheless, the formation of pyrene excimers in the solid state has not been well understood compared to that in its solution state. It has been shown that electrospun pyrene/polystyrene/tetrabutylammonium hexafluorophosphate thin films demonstrate high selectivity and sensitivity in detecting nitro-aromatic, nitrate ester, and nitro-amine explosives, while thin films made from the same solution via other procedures (e.g., spinning coating, solution casting, dip coating) do not exhibit satisfactory detecting capability, partially because of the low excimer fluorescence. In this study, three parameters, evaporation rate, temperature, and solvent vapor pressure, that most likely influence the formation of pyrene excimers are examined individually. Experimental results show that high solvent vapor pressure annealing plays the most important role in enhancing the pyrene excimer fluorescence, while high-temperature (around and greater than the glass transition temperature of the polymer) annealing in the absence of the solvent significantly suppresses the excimer fluorescence, indicating that pyrene excimers are metastable in the polymer thin films. Evaporation rate has a marginal effect on the formation of pyrene excimers. Moreover, this study has shown that it is possible to convert a low excimer fluorescence polymer film to a high-fluorescence one through high solvent vapor pressure annealing, which provides a novel strategy for manufacturing high-sensitivity sensing materials

Determination of factors affecting overall survival.

<p>Patients overall survival analyses were made between two groups: (A) patients with or without mutations in <i>NLRP</i> genes; (B) patients with or without mutations in <i>TP53</i> genes; (C) patients with tumors that harbored <i>TLR</i> mutations and those without <i>TLR</i> mutations; (D) patients with or without HPV infections; (E) patients with low stage (stage II) or advanced stage (stage III and beyond) tumors; (F) patients of less or more than 56 years old; (G) patients who received no adjuvant therapy, radiotherapy alone or both chemotherapy and radiotherapy.</p

Mutation rates comparisons.

<p>(A) Numbers of missense and nonsense mutations were compared between tumors with or without <i>NLRP</i> mutations. (B) Numbers of missense and nonsense mutations were compared between tumors with or without <i>TP53</i> mutations. (C) Numbers of missense and nonsense mutations were compared between tumors with or without <i>TLR</i> genes mutations. (D) Mutation rates [shown as mutations per million base (MB) pairs] were compared between tumors with or without <i>NLRP</i> mutations. (E) Mutation rates [shown as mutations per million base (MB) pairs] were compared between tumors with or without <i>TP53</i> mutations. (F) Mutation rates [shown as mutations per million base (MB) pairs] were compared between tumors with or without <i>TLR</i> genes mutations. P value less than 0.05 was considered significant.</p