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

<i>ortho-</i>Directing Chromium Arene Complexes as Efficient Mediators for Enantiospecific C(sp²)–C(sp³) Cross-Coupling Reactions

<p>Supplemental material, supplementary_table_6 for HDAC3-mediated silencing of miR-451 decreases chemosensitivity of patients with metastatic castration-resistant prostate cancer by targeting NEDD9 by Dong-qin Chen, Chen Yu, Xue-feng Zhang, Zhong-fang Liu, Rui Wang, Min Jiang, Hao Chen, Feng Yan, Min Tao, Long-bang Chen, Hong Zhu and Ji-feng Feng in Therapeutic Advances in Medical Oncology</p

Perovskite/Poly(3-hexylthiophene)/Graphene Multiheterojunction Phototransistors with Ultrahigh Gain in Broadband Wavelength Region

Organometal halide perovskite materials have attracted much attention recently for their excellent optoelectronic properties. Here, we report an ultrasensitive phototransistor based on the multiheterojunction of CH₃NH₃PbI_3–<i>x</i>Cl_<i>x</i> perovskite/poly­(3-hexylthiophene)/graphene for the first time. Since the photoexcited electrons and holes are effectively separated by the poly­(3-hexylthiophene) layer, high-density electrons are trapped in the perovskite layer, leading to a strong photogating effect on the underlying graphene channel. The phototransistor demonstrates an unprecedented ultrahigh responsivity of ∼4.3 × 10⁹ A/W and a gain approaching 10¹⁰ electrons per photon, respectively. More importantly, the device is sensitive in a broadband wavelength region from ultraviolet to near-infrared, which has not yet been achieved with other perovskite photodetectors. It is expected that the novel perovskite phototransistor will find promising applications as photodetection and imaging devices in the future

Solution-Processable Low-Voltage and Flexible Floating-Gate Memories Based on an n‑Type Polymer Semiconductor and High‑<i>k</i> Polymer Gate Dielectrics

High-performance low-voltage flash memories based on organic floating-gate field-effect transistors are prepared by a solution process for the first time. Transistors with a high-mobility n-type polymer semiconductor, poly­{[<i>N</i>,<i>N</i>^′-bis­(2-octyldodecyl)­naphthalene-1,4,5,8-bis­(dicarboximide)-2,6-diyl]-<i>alt</i>-5,5′-(2,2′-bithiophene)}, and a high-<i>k</i> polymer gate dielectric, poly­(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) (<i>k</i> ≈ 60), are successfully fabricated on flexible substrates. A thin layer of Au nanoparticles is embedded in the gate dielectric, which can store injected charge from the channel and result in a memory effect. The organic memories demonstrate high carrier mobilities (>0.3 cm²/(V s)), low program/erase voltages (±6 V), little degradation after 10⁵ program/erase cycles, and good retention after 10⁵ s, which suggest great promise in the application of nonvolatile memories in flexible electronics

Porating Anion-Responsive Copolymeric Gels

A polymerizable ionic liquid surfactant, 1-(11-acryloyloxyundecyl)-3-methylimidiazolium bromide (ILBr), was copolymerized with methyl methacrylate (MMA) in aqueous microemulsions at 30% (ILBr w/w) and various water to MMA ratios. The ternary phase diagram of the ILBr/MMA/water system was constructed at 25 and 60 °C. Homopolymers and copolymers of ILBr and MMA were produced by thermally initiated chain radical microemulsion polymerization at various compositions in bicontinuous and reverse microemulsion subdomains. Microemulsion polymerization reaction products varied from being gel-like to solid, and these materials were analyzed by thermal and scanning electron microscopy methods. Microemulsion polymerized materials were insoluble in all solvents tested, consistent with light cross-linking. Ion exchange between Br^– and PF₆^– in these copolymeric materials resulted in the formation of open-cell porous structures in some of these materials, as was confirmed by scanning electron microscopy (SEM). Several compositions illustrate the capture of prepolymerization nanoscale structure by thermally initiated polymerization, expanding the domain of compositions exhibiting this feat and yet to be demonstrated in any other system. Regular cylindrical pores in interpenetrating ILBr-<i>co</i>-MMA and PMMA networks are produced by anion exchange in the absence of templates. A percolating cluster/bicontinuous transition is “captured” by SEM after using anion exchange to visualize the mixed cluster/pore morphology. Some design principles for achieving this capture and for obtaining stimuli responsive solvogels are articulated, and the importance of producing solvogels in capturing the nanoscale is highlighted

Electrochemiluminescent Imaging for Multi-immunoassay Sensitized by Dual DNA Amplification of Polymer Dot Signal

A true-color electrochemiluminescent (ECL) imaging strategy was designed for a multi-immunoassay of proteins by coupling highly efficient polymer dots (Pdots) with dual DNA amplification. The Pdots were prepared by nanoprecipitation of poly­[(9,9-dioctylfuorenyl-2,7-diyl)-<i>alt</i>-co-(1,4-benzo-{2,1′,3}-thiadiazole)] in the presence of poly­(styrene-<i>co</i>-maleic anhydride) and functionalized with DNA1 that hybridized with black hole quencher-labeled DNA2 to self-quench the ECL emission. The Pdots modified Au/ITO electrode showed 100-fold stronger ECL emission than the Pdots modified ITO electrode. After the capture antibody immobilized on Au/ITO slide recognized the target protein and then reacted with biotin-labeled antibody, streptavidin and biotin-labeled oligonucleotide, respectively, a large number of DNA1 functionalized Pdots could be introduced onto the slide surface by rolling circle amplification of the oligonucleotide to trigger the enzymatically cyclic release of the Pdots from the self-quenched probes to solution in the presence of Exo III. The dual DNA amplification produced a greatly amplified ECL signal for true-color ECL imaging. Using carcinoembryonic antigen, cytokeratin-19-fragment, and neuron-specific enolase as a lung cancer-specific biomarker panel, the ECL imaging-based multi-immunoassay exhibited excellent performance with a linear range of 1 pg mL^–1 to 500 ng mL^–1 and limits of detection of 0.17, 0.12, and 0.22 pg mL^–1, respectively. The proposed method could accurately detect these biomarkers in clinical human serum samples for lung cancer screening. The Pdots-based true-color ECL imaging approach possessed the advantages of visual analysis along with wide detection range and high sensitivity and thus has great potential in clinical application

Novel Calcium Oxide-Enhancement Phosphorus Recycling Technique through Sewage Sludge Pyrolysis

Municipal sewage sludge is abundant and rich in phosphorus, making it a promising alternative phosphorus reserve. A good knowledge of the phosphorus transformation during pyrolysis will underlie the industrial phosphorus recycling and reclamation of sewage sludge. This work first advanced a novel calcium oxide (CaO)-enhancement phosphorus-recycling technique based on pyrolysis of sewage sludge, by regulating the transformation of phosphorus in sewage sludge during pyrolysis through the CaO addition. The obtained results indicated that CaO addition promoted the formation of hydroxylapatite, which is a desirable phosphorus species for plant growth. The factors of pyrolysis temperature and inherent composition of sewage sludge both influenced the fraction of hydroxylapatite during pyrolysis. An increase in pyrolysis temperature and a sludge with a high content of ash and a low content of volatile matters potentially promoted the transformation of P from organic phosphorus to the inorganic species during pyrolysis with the addition of CaO, particularly for the formation of hydroxylapatite. Increasing CaO addition significantly increased the fraction of hydroxylapatite in the obtained char, and the maximum content of 25 wt % hydroxylapatite over total phosphorus was attained. This enhanced transformation of hydroxylapatite may be potentially attributed to the interaction between CaO and the polyphosphate with the aid of the inherent minerals that appeared to benefit the immobilization of phosphorus during sludge pyrolysis. As the formation of hydroxylapatite was enhanced, this facile technology of CaO-enhancement sewage sludge pyrolysis could be used for the direct recycling of P as well as the disposal of sewage sludge

AC Measurements Using Organic Electrochemical Transistors for Accurate Sensing

Organic electrochemical transistors (OECTs) have been successfully employed for a variety of applications , especially chemical and biological sensing. Although the device response to analytes can be directly monitored by measuring steady-state channel currents of the devices, it is challenging to obtain stable signals with high signal-to-noise ratios. In this work, we developed a novel method for electrochemical sensing by measuring both the transconductance and the phase of the AC channel current for the first time. Then we successfully realized highly sensitive ion strength sensors and dopamine sensors based on the AC method. Our results indicate that the AC method is more sensitive than typical DC methods and can provide more stable data in sensing applications. Considering that the sensors can be conveniently integrated with AC circuits, this technology is expected to find broad applications in the future

Neutral-Color Semitransparent Organic Solar Cells with All-Graphene Electrodes

Graphene has been considered as a promising material for transparent electrodes due to its advantages including ultrahigh carrier mobilities, high optical transmittance, excellent mechanical flexibility, and good stability. Solar cells with all-graphene electrodes are potentially low-cost, high-performance, and environmental friendly, which however have not been realized until now. Here, we report the fabrication of semitransparent organic photovoltaics (OPVs) with graphene transparent electrodes as both cathode and anode, which can absorb light from both sides with the power conversion efficiency up to 3.4%. Meanwhile, the OPVs have a neutral color and show the transmittance of ∼40% in the visible region, making them suitable for some special applications, such as power-generating windows and building integrated photovoltaics. This work demonstrates the great potential of graphene for the applications in carbon-based optoelectronic devices

Dynamics of Photogenerated Surface Charge on BiFeO₃ Films

We report on the spatial and temporal evolution of photoinduced charge generation and carrier separation in heteroepitaxial BiFeO₃ thin films deposited on Nb:SrTiO₃ as measured in ambient at room temperature with Kelvin probe and piezoresponse force microscopy. Contributions from the self-poled and ferroelectric polarization charge are identified from the time evolution of the correlated surface potential and ferroelectric polarization in films as grown and following poling, and at different stages and intensities of optical illumination. Variations in the surface potential with bias voltage, switching history, and illumination intensity indicate how both bulk ferroelectric photovoltaic and the domain wall offset potential mechanisms contribute to the photogenerated charge