Search

We report on the optoelectronic properties of a series of unsymmetrical π-conjugated phenyleneethynylene macromolecules bearing ferrocene (Fc) as the electron-donor group (D), (benzyl) benzoate (Bz) or benzoic acid (Ac) as the electron attractor group (A) and connected through 2,5-di(alcoxy) phenyleneethynylene(s) (

A π-conjugated polymer (PBQT) containing bis-(2-ethylhexyloxy)-benzo [1,2-b’] bithiophene (BDT) units alternated with a quinoline-vinylene trimer was obtained by the Stille reaction. The chemical structure of the polymer was verified by nuclear magnetic resonance (1H NMR), Fourier transform infrared (FT-IR), and mass spectroscopy (MALDI-TOF). The intrinsic photophysical properties of the solution were evaluated by absorption and (static and dynamic) fluorescence. The polymer PBQT exhibits photochromism with a change in absorption from blue (449 nm) to burgundy (545 nm) and a change in fluorescence emission from green (513 nm) to orange (605 nm) due to conformational photoisomerization from the trans to the cis isomer, which was supported by theoretical calculations DFT and TD-DFT. This optical response can be used in optical sensors, security elements, or optical switches. Furthermore, the polymer forms spin-coated films with absorption properties that cover the entire visible range, with a maximum near the solar emission maximum. The frontier molecular orbitals, HOMO and LUMO, were calculated by cyclic voltammetry, and values of −5.29 eV and −3.69, respectively, and a bandgap of 1.6 eV were obtained, making this material a semiconductor with a good energetic match. These properties could suggest its use in photovoltaic applications.

Este artículo presenta los resultados obtenidos al aplicar en la unidad de electricidad el diseño de una propuesta didáctica experimentalen un colegio científico de Costa Rica. Se realizó una investigación cuantitativa con un diseño cuasi experimental mediante una pruebaconceptual adaptada de la Asociación Americana de Profesores de Física aplicada como pretest y postest para medir el modelo deganancia conceptual de Hake, el factor de concentración de Bao y Redish y una prueba de hipótesis mediante la t-student. Este trabajoevidencia que los resultados adquiridos con el empleo de este diseño generaron en este sistema educativo cambios notorios y significativosen el proceso de enseñanza-aprendizaje y a la vez se relaciona como un insumo de vital importancia para la educación diversificadaa nivel nacional. Se espera que esta experiencia de pie a aplicaciones educativas en otras áreas del conocimiento.

Introducción: los métodos de aprendizaje automático permiten manejar datos estructurados y no estructurados para construir modelos predictivos y apoyar la toma de decisiones. Objetivo: identificar los métodos de aprendizaje automático aplicados para predecir el comportamiento epidemiológico de enfermedades arbovirales utilizando datos de vigilancia epidemiológica. Metodología: se realizó búsqueda en EMBASE y PubMed, análisis bibliométrico y síntesis de la información. Resultados: se seleccionaron 41 documentos, todos publicados en la última década. La palabra clave más frecuente fue dengue. La mayoría de los autores (88,3 %) participó en un artículo de investigación. Se encontraron16 métodos de aprendizaje automático, el más frecuente fue Red Neuronal Artificial seguido de Máquinas de Vectores de Soporte. Conclusiones: en la última década se incrementó la publicación de trabajos que pretenden predecir el comportamiento epidemiológico de arbovirosis por medio de diversos métodos de aprendizaje automático que incorporan series de tiempo de los casos, variables climatológicas, y otras fuentes de información de datos abiertos.

A series of new symmetrical highly substituted BODIPYs 6 a-l was synthesized through a prefunctionalization approach in 35 %-89 % yields from the pyrrole core. This strategy allowed modulation of the substituents at the different positions based on the choice of Fischer's alkynyl carbenes, oxazolones and aldehydes used as precursors. The substituent variation at positions 2, 6, 3 and 5 had the greatest effect on the modulation of their photophysical properties such as absorption (λ

Objective This study aimed to compare the epidemiology of bacterial meningitis (BM) before and after vaccination, and identify possible risk factors associated with mortality. Methods The medical and microbiologic records of children (1 month–18 years) with a discharge diagnosis of BM in a third level children's hospital in Mexico from 1990 to 2018 were reviewed. The epidemiology, pathogens, and outcomes were compared before and after introducing Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines to the Mexican immunization schedule. Risk factors associated with mortality were determined. Results In the 28-year period, 226 cases with BM were included 55.8% (1990–1999), 27.4% (2000–2008), and 16.8% (2009–2018) (p = 0.0001). The most frequent pathogen was Hib, documented in 39% of cases. There was a reduction in neurological complications after introducing the Hib conjugate vaccine (59 vs. 39%; p = 0.003) and sequelae after the Streptococcus pneumoniae conjugate vaccine (43 vs. 35%; p = 0.05). Independent risk factors associated with mortality were coma (odds ratio [OR]: 15 [2.9–78]), intracerebral bleeding (OR: 3.5 [1.4–12]), and pneumococcal meningitis (OR: 9.4 [2.2–39]). Conclusion Since the introduction of Hib and pneumococcal conjugate vaccines to the national immunization schedule, there was a reduction in BM cases, mainly associated with the Hib vaccine, with the consequent reduction of neurological complications and sequelae.

Autologous reconstruction for major facial defects is primarily considered for patient's lifetime care. There are situations, however, when autologous reconstruction is not ideal or feasible, and prosthetic reconstruction is necessary to reconstruct missing anatomy or to complement surgical reconstruction. The history of facial prosthetic reconstruction can be traced for millennia. At our craniofacial center, craniomaxillofacial prosthetic rehabilitation has been incorporated in the care provided to our patients since the center's inception, more than 70 years ago.The purpose of this review is to present the evolution of our current thinking based on our long experience since the implementation of computer-assistive technologies over 15 years ago, to further improve our patients' overall rehabilitation.These applications include all stages of prosthetic care from planning, design through device delivery, and for lifetime maintenance. The collaboration among surgeons and anaplastologists is fundamental to achieving optimal patient outcomes and in the success of our technology-based practice. Such collaboration starts with the patient's decision to proceed with prosthetic rehabilitation and continues with postoperative care and lifetime management of the patient's prosthetic device and prosthesis-bearing soft tissue.Although computer-assistive techniques often represent a substantial financial investment, the benefits of using them demonstrate clear advantages to both the clinician and patient. These benefits include: Improved predictability of outcomes, surgeon preparedness, reduction in operating room time, reduction in overall treatment times, improved precision and anatomical accuracy, improved treatment efficiencies, and overall treatment experience, particularly for those patients traveling great distances for access to care.Representative examples will be presented.

Two series of 2,5-di(butoxy)phenyleneethynylenes, one halogenated (nPEC4-X; n=2, 3, or 4) and the other boron-dipyrromethene (BODIPY) terminated (nPEC4-By; n=3, 4, or 5; By=BODIPY), were synthesized monodirectionally by the step-by-step approach and the molecular structure was corroborated by NMR spectroscopy (1 H, 13 C-DEPTQ-135, COSY, HSQC, HMBC, 11 B, 19 F) and MALDI-TOF mass spectrometry. The multiplicity and J-coupling constants of 1 H, 11 B, and 19 F/11 B NMR signals revealed, in the nPEC4-By series, that the phenyl in the meso position of BODIPY becomes electronically part of the conjugation of the phenyleneethynylene chain, whereas BODIPY is electronically isolated. The photophysical, electrochemical, and theoretical studies confirm this finding because the properties of nPEC4-By are comparable to those of the nPEC4-X oligomers and BODIPY, indicating negligible electron communication between BODIPY and the nPEC4 moieties. Nevertheless, energy transfer (ET) from nPEC4 to BODIPY was rationalized by spectroscopy and theoretical calculations. Its yield decreases with the nPEC4 conjugation length, according to the increase in distance between the two chromophores, resulting in dual emission for the longest oligomer in which ET is quenched.

A series of water soluble 8-alcoxypyrene-1,3,6-trisulfonic sodium salts bearing different alcoxy lateral chains and functional end groups was synthesized and the molecular structure was corroborated by nuclear magnetic resonance spectroscopy. The photophysical properties in water analyzed by UV-Vis and static and dynamic fluorescence revealed that all of the pigments emit in the blue region at a maximal wavelength of 436 nm and with fluorescence lifetimes in the range of ns. Among them, sodium 8-((10-carboxydecyl) oxy) pyrene-1,3,6-trisulfonate M1 exhibits a high fluorescence quantum yield (ϕ = 80%) and a good interaction with B. subtilis LPM1 rhizobacteria; this has been demonstrated through in vitro staining assays. Tomato plants (Solanum lycopersicon cv. Micro-Tom) increased the release of root exudates, mainly malic and fumaric acids, after 12 h of treatment with benzothiadiazole (BTH) as a foliar elicitor. However, the chemotaxis analysis demonstrated that malic acid is the most powerful chemoattractant of the rhizobacteria Bacillus subtilis LPM1: in agar plates, a major growth (60 mm) was found for a concentration of 100 mM, while in capillary tubes, the earliest response was at 30 min with 3.3 × 108 CFU mL−1. The confocal microscopic analysis carried out on the tomato roots of the pyrene stained B. subtilis LPM1 revealed that this bacterium mainly colonizes the epidermal zones, i.e. the junctions to primary roots, lateral roots and root hairs, meaning that these root hair sections are the highest colonisable sites involved in the biosynthesis of exudates. This fluorescent pyrene marker M1 represents a valuable tool to evaluate B. subtilis–plant interactions in an easy and quick test in both in vitro and in vivo tomato crops.

Resumen Introduccion La transfusion posoperatoria es una complicacion frecuente de la artroplastia de rodilla. El acido tranexamico (AT) ha demostrado eficacia en disminuir la probabilidad de sangrado, sin embargo, son pocos los estudios en cuanto al tema. Los objetivos del estudio son: 1) Comparar el efecto de dosis unica de 1 g de acido tranexamico preoperatoria en la tasa de transfusion en pacientes a quienes se realizo artroplastia de rodilla entre enero de 2010 y diciembre de 2016. 2) Caracterizar poblacion de pacientes a quienes se realizo artroplastia de rodilla. 3) Determinar tasa de transfusion sanguinea en grupos de estudio. 4) Determinar factores de riesgo para transfusion sanguinea en pacientes con artroplastia de rodilla. Materiales y Metodos Estudio observacional descriptivo de tipo corte transversal analitico retrospectivo. Resultados Tasa de transfusion en grupo sin AT = 15,2%; en grupo con AT = 1,2%. La sangre perdida y el tiempo quirurgico no presentaron diferencias estadisticamente significativas entre los grupos (p >0,05). Se consideran factores de riesgo: anticoagulacion (OR 3,52; IC95% 1,28-9,65), insuficiencia renal cronica (OR 5,91; IC95% 1,11-31,27) y artritis reumatoidea (OR 55,83; IC95% 18,34-169,91). Discusion Segun regresion logistica, la cantidad de sangre perdida y administracion del AT pueden predecir con un 97.5% de acierto la probabilidad de transfusion ante presencia de artritis reumatoide. La perdida sanguinea mayor a 400 cc aumenta significativamente la probabilidad de transfusion cuando no se administra AT. El uso de AT preoperatorio es efectivo en reducir la tasa de transfusion sanguinea en pacientes a quienes se realiza ATR. Nivel de Evidencia: III

Significance Freshwaters inextricably link flows of carbon between the land, oceans, and atmosphere. Resulting carbon dioxide supersaturation relative to the atmosphere in most of the world’s lakes and rivers has long been assumed to come from aerobic respiration. Although carbon dioxide also comes from the oxidation of anaerobically produced methane, this has been largely ignored within freshwaters. Here, we use stable carbon isotopes of carbon dioxide and methane to show that a nontrivial proportion of the total dissolved carbon dioxide in a tropical flood pulse lake comes from methane oxidation. Seasonal pulses of flooding are common in the tropics, suggesting that coupled methane production and oxidation likely contribute more broadly to flows of carbon between the land, understudied tropical freshwaters, and atmosphere.

Carbon dioxide (CO

Se sintetizaron nanopartículas de plata AgNPs a partir de nitrato de plata, empleando borohidruro de sodio como agente reductor y poli(etilendioxitiofeno):poli(estiren sulfonato de sodio), PEDOT:PSS, como estabilizador. Se variaron los siguientes parámetros de síntesis: 1) contenido relativo entre PEDOT y PSS, utilizando tres formulaciones comerciales; y 2) relación molar entre sal de plata y agente reductor. Por espectroscopia UV-Vis, se corroboró la formación de las AgNPs mediante la banda plasmónica a ~ 400 nm, además se observaron cambios espectrales para el PEDOT cuando se utilizan las formulaciones con mayor contenido de PEDOT, y relación sal/agente reductor de ~1, lo cual de acuerdo con los espectros Raman se asocia con un cambio conformacional del PEDOT hacia una estructura más benzenoide. En las demás condiciones, las propiedades espectroscópicas son similares a las de nanopartículas preparadas con puro PSS. Con base en los resultados, se plantea que las AgNPs se estabilizan con el PSS en exceso, afuera de los dominios PEDOT:PSS, cuando la formulación tiene más contenido de PSS o empleando bajas cantidades de NaBH4. Al incrementar el contenido de NaBH4, las AgNPs se forman también adentro de los dominios. El mecanismo de estabilización permite así modular las propiedades ópticas y eléctricas de las NPs.

ObjectiveTo estimate COVID-19 and pre-pandemic low respiratory infection (LRI) mortality in children and young people in Mexico.Material and methodsWe estimated the percentage of total mortality attributable to COVID-19 (95% confidence intervals; 95%CI) and corresponding estimates for pre-pandemic LRI mortality.ResultsIn 2019, LRIs represented 8.6% (95%CI 8.3, 8.9) of deaths in children 0-9 years and 2.0% (95%CI 1.8, 2.3) in those aged 10-19 years. In 2020, corresponding estimates for COVID-19 were 4.4% (95%CI 4.1, 4.6) and 3.7% (95%CI 3.4, 4.1).ConclusionsRelative to LRI, COVID-19 may be exerting considerable mortality burden, particularly in older children and adolescents.

Objective. To estimate Covid-19 and pre-pandemic low respiratory infection (LRI) mortality in children and adolescents in Mexico. Materials and methods. We estimated the percentage of total mortality attributable to Covid-19 (95% confidence intervals; 95%CI) and made the corresponding estimates for pre-pandemic LRI mortality. Results. In 2019, LRIs represented 8.6% (95%CI 8.3, 8.9) of deaths in children aged 0-9 years, and 2.0% (95%CI 1.8, 2.3) in those aged 10-19 years. In 2020, the corresponding estimates for Covid-19 were 4.4% (95%CI 4.1, 4.6) and 3.7% (95%CI 3.4, 4.1). Conclusions. Relative to LRI, Covid-19 may be exerting a considerable mortality burden, particularly in older children and adolescents.

Primary rib cage tuberculosis (TB) is an infrequent form of presentation and represents 1% of all cases of osteoarticular TB. We report three cases of children who were previously healthy and who began with swelling of the anterior surface of the rib as initial manifestation of TB. The most important clinical presentations in this series were swelling and pain, with lytic lesions and a soft tissue mass in image studies simulating oncologic pathologies. Because none of the cases had positive epidemiological contact, TB was initially not considered, so the delay in diagnosis from the onset of symptoms was 4, 1, and 2 months, respectively. The diagnosis was made through histomorphological analyses. Treatment was administered during 12, 10, and 9 months. Posttreatment studies did not show any evidence of extrapulmonary TB and until date, the patients remained without relapse or active disease. The findings in our cases illustrate that the diagnosis of chest wall TB should be suspected in all patients from endemic areas who present rib injury.

Fat grafting has become a well-accepted surgical modality to correct soft tissue facial defects and asymmetries with overall good results. Several techniques have been reported over the last few years to assist in improving accurate evaluation of facial defects and in the preoperative planning of the reconstruction. Such techniques include among others, computer tomography, three-dimensional (3D) photogrammetry, high resolution ultrasound, and 3D laser scanning. There are advantages and disadvantages for each technique.With the rapid advance of 3D technologies that have become readily available to clinicians, new clinical applications continually emerge to guide and facilitate reconstructive procedures. The authors explored the possibility of fabricating a 3D printed surgical guide to define volume differences for soft tissue reconstruction in patients with facial asymmetry. The model was developed through the authors' virtual surgical simulation and planning system that consists of computer-assisted design (CAD) and 3D printing (3DP).Three-dimensional volumetric scans of patients' faces were analyzed with computer-aided design to quantify areas of facial asymmetry. Surgical guides with containers defining volumetric differences were fabricated using 3D printing to identify and quantify areas of soft tissue deficiency. The 3D printed patient-specific, guides were sterilized and used by the surgeon intraoperatively to accurately mark the areas of soft deficiency. Thus, facial symmetry was achieved by fat grafting the predetermined volume differences defined in the surgical guides. A postop mask was used by the surgeon at the end of the procedure and during follow-up clinic visit to verify and evaluate accurate fat grafting placement as well as to determine areas where to add volume if needed.This paper details the rational for the authors' approach, outlines the technical planning and fabrication process of these patient-specific custom surgical guides with quantified volumetric containers and their intraoperative use by the surgeon. Despite the authors' limited experience we conclude that the authors' technique offer surgeons a precise means for accurate volumetric reconstruction of facial asymmetry.

A couple of luminescent organotin compounds derivated from ligands-ONO were obtained by multicomponent microwave assisted synthesis in short time (15 min) and good yields: ((E)-8, 8-8-diphenylbenzo[d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (1) and (E)11, 13- di-tert-butyl, 8- diphenylbenzo [d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (2)). Both compounds were fully characterized by NMR (1H, 13C, and 119Sn; 2D-NMR, HETCOR and COSY), UV–Vis, IR, and high-resolution mass spectrometry. The X-ray structures of two complexes demonstrate that the tin atoms adopt a bipyramidal trigonal geometry. The 119Sn NMR chemical shifts of the tin atom in the complexes are also consistent with the presence of pentacoordinate tin centers. The photophysical properties in solution and solid state, DFT, and voltammetry the two complexes have been determined.

The preparation of a recyclable palladium complex supported on coated silica nanoparticles (SiNP) and its effectiveness as a catalyst in the Heck reaction is described. Functionalized silica-based NP were synthesized in three steps. First, commercial SiNP were subjected to a CS2 cold plasma. Thus, a thin coating film was formed, along with the creation of a thiol functional surface. Subsequently, a thiol-ene reaction with 2-vinylpyridine induced by AIBN produced (Py)-CH2-CH2S covalently bonded to the SiNP, which after PdCl2(CH3CN)2, ligand exchange afforded the corresponding palladium complex catalyst (Pd-SiNP). Functionalized Pd-SiNP were characterized by SEM, ICP, and XPS spectroscopy. The SiNP were straightforwardly converted to an effective palladium catalyst applicable in a number of Heck cross-coupling reactions with iodobenzene (IBz) and a variety of vinyls. Indeed, such heterogeneous catalyst probed to be recyclable (up to 9 times). Nevertheless, leaching of metal was evidenced by TEM, HRTEM, XRD, and XPS. Furthermore, due to the outstanding results, we extended the use of the new heterogeneous catalyst to achieve the synthesis of a soluble phenylenevinylene type (PPV) copolymer from 1,4-bis(dodecyloxy)-2,5-diiodobenzene and p-divinylbenzene (DVB).

COVID-19 affects the paediatric population less frequently than adults. A retrospective study was performed in a tertiary paediatric hospital in Mexico City in children

Supplemental Table 1: Age-specific data for Mexico showing all-cause and LRI mortality and 95% confidence intervals (95%CI) for 2019, Mexico City, August 2021Supplemental Table 2: Age-specific data for Mexico showing all-cause and COVID-19 mortality for 2020 and first half of 2021, Mexico City, August 2021

Thin films of a series of symmetrical 2,5-bis(dodecanoxy)phenyleneethynylenes, bearing a butadiyne central group and 4, 6 and 8 phenyleneethynylene moieties, were prepared by spin coating. In general, narrower and red shifted peaks are observed in both absorption and emission spectra with respect to the solutions previously reported, however, the fluorescence quantum yield was quenched. All of these features are explained with the planarization of the conjugated chain, and intra/intermolecular interactions, as supported by spectroscopic aggregation studies and by atomic STM and microscopic AFM characterization. By cathodoluminescence spectroscopy, hot charged states are found that may also affect the fluorescence and electroluminescence properties. From the series, the latter were studied for the hexamer 6DAc for which an oLED with configuration ITO/PEDOT:PSS/6DAc/Al was constructed in ambient conditions, giving a threshold voltage of 11 V and quantum yield of 0.031 ph/e%, of the same order of other phenyleneethynylenes or phenylenebutadyines devices.