Plasmon spectroscopy: Theoretical and numerical calculations, and optimization techniques

30 págs.; 22 figs.; 1 tab.; Open Access funded by Creative Commons Atribution Licence 3.0We present an overview of recent advances in plasmonics, mainly concerning theoretical and numerical tools required for the rigorous determination of the spectral properties of complex-shape nanoparticles exhibiting strong localized surface plasmon resonances (LSPRs). Both quasistatic approaches and full electrodynamic methods are described, providing a thorough comparison of their numerical implementations. Special attention is paid to surface integral equation formulations, giving examples of their performance in complicated nanoparticle shapes of interest for their LSPR spectra. In this regard, complex (single) nanoparticle configurations (nanocrosses and nanorods) yield a hierarchy of multiple-order LSPR s with evidence of a rich symmetric or asymmetric (Fano-like) LSPR line shapes. In addition, means to address the design of complex geometries to retrieve LSPR spectra are commented on, with special interest in biologically inspired algorithms. Thewealth of LSPRbased applications are discussed in two choice examples, single-nanoparticle surface-enhanced Raman scattering (SERS) and optical heating, and multifrequency nanoantennas for fluorescence and nonlinear optics.J.A.S.-G. and R.P.-D. acknowledge the Spanish >Ministerio de Economía y Competitividad>, through the Consolider-Ingenio project EMET (CSD2008- 00066) and NANOPLAS+ (FIS2012-31070), for financial support.Peer Reviewe

Multiscale characterisation of cortical bone tissue

Multiscale analysis has become an attractive technique to predict the behaviour of materials whose microstructure strongly changes spatially or among samples, with that microstructure controlling the local constitutive behaviour. This is the case, for example, of most biological tissues-such as bone. Multiscale approaches not only allow, not only to better characterise the local behaviour, but also to predict the field-variable distributions (e.g., strains, stresses) at both scales (macro and micro) simultaneously. However, multiscale analysis usually lacks sufficient experimental feedback to demonstrate its validity. In this paper an experimental and numerical micromechanics analysis is developed with application to cortical bone. Displacement and strain fields are obtained across the microstructure by means of digital image correlation (DIC). The other mechanical variables are computed following the micromechanics theory. Special emphasis is given to the differences found in the different field variables between the micro- and macro-structures, which points out the need for this multiscale approach in cortical bone tissue. The obtained results are used to establish the basis of a multiscale methodology with application to the analysis of bone tissue mechanics at different spatial scales

Synthesis of Bioactive Speciosins G and P from Hexagonia speciosa

The first total synthesis of speciosins P and G, previously isolated from Hexagonia speciosa, is reported. These compounds have been synthesized by Sonogashira coupling from readily available starting materials. Siccayne was also synthesized from the same starting material in two steps along with a number of other derivatives. The compounds were tested in the wheat coleoptile bioassay. The most active compound was the intermediate 18, followed by 29 and 17. The structural requirements for activity in these compounds are the presence of methoxy groups in the aromatic ring and a formyl or hydroxy group in the side chain

Time-Dependent Collagen Fibered Structure in the Early Distraction Callus: Imaging Characterization and Mathematical Modeling

Collagen is a ubiquitous protein present in regenerating bone tissues that experiences multiple biological phenomena during distraction osteogenesis until the deposition of phosphate crystals. This work combines fluorescence techniques and mathematical modeling to shed light on the mechano-structural processes behind the maturation and accommodation-to-mineralization of the callus tissue. Ovine metatarsal bone calluses were analyzed through confocal images at different stages of the early distraction osteogenesis process, quantifying the fiber orientation distribution and mean intensity as fiber density measure. Likewise, a mathematical model based on the experimental data was defined to micromechanically characterize the apparent stiffening of the tissue within the distracted callus. A reorganization of the fibers around the distraction axis and increased fiber density were found as the bone fragments were gradually separated. Given the degree of significance between the mathematical model and previous in vivo data, reorganization, densification, and bundle maturation phenomena seem to explain the apparent mechanical maturation observed in the tissue theoretically.This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness [Grant No. DPI2017-82501-P]; the Spanish State Research Agency (AEI) [Grant No. PID2020-113790RB-I00/AEI/ 10.13039/501100011033]; and the European Regional Development Fund (FEDER) with the Junta de Andalucı ´a [Grant No. US-1261691]

Synthesis, antibacterial and antifungal activities of naphthoquinone derivatives: a structure–activity relationship study

The synthesis of 1,4-naphthoquinone derivatives is of great interest since these compounds exhibit strong activity as antimalarial, antibacterial, antifungal and anticancer agents. A series of 50 naphthoquinone derivatives was synthesized and evaluated for antibacterial and antifungal activity against Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Candida krusei, Candida parapsilosis and Cryptococcus neoformans using the broth microdilution method. The Candida species were the most susceptible microorganisms. Halogen derivatives of 1,4-naphthoquinone presented strong activity, e.g., 2-bromo-5-hydroxy-1,4-naphthoquinone, which exhibited inhibition at an MIC of 16 lg/ mL in S. aureus, and 2-chloro-5,8-dihydroxy-1,4-naphthoquinone, with an MIC of 2 lg/mL in C. krusei. These compounds showed higher activity against fungi, but the antibacterial activities were very low. The study of structure–activity relationships is very important in the search for new antimicrobial drugs due to the limited therapeutic arsenal

A Study of PLA Thin Film on SS 316L Coronary Stents Using a Dip Coating Technique

The dip coating process is one of the recognized techniques used to generate polymeric coatings on stents in an easy and low-cost way. However, there is a lack of information about the influence of the process parameters of this technique on complex geometries such as stents. This paper studies the dip coating process parameters used to provide a uniform coating of PLA with a 4–10 µm thickness. A stainless-steel tube (AISI 316L) was laser-cut, electropolished, and dip-coated in a polylactic acid (PLA) solution whilst changing the process parameters. The samples were characterized to examine the coating’s uniformity, thickness, surface roughness, weight, and chemical composition. FTIR and Raman investigations indicated the presence of PLA on the stent’s surface, the chemical stability of PLA during the coating process, and the absence of residual chloroform in the coatings. Additionally, the water contact angle was measured to determine the hydrophilicity of the coating. Our results indicate that, when using entry and withdrawal speeds of 500 mm min−1 and a 15 s immersion time, a uniform coating thickness was achieved throughout the tube and in the stent with an average thickness of 7.8 µm.We gratefully thank Consejo Nacional de Humanidades, Ciencia y Tecnología (Conahcyt) (CVU: 931068) and Tecnologico de Monterrey for providing scholarship and tuition to the lead author of the Ph.D. degree program. We thank Ciencia de Frontera Consejo Nacional de Humanidades, Ciencias y Tecnologías: CF-2023-I-2901. The Advanced Manufacturing research group (Tecnologico de Monterrey) supported the acquisition of materials. This research did not receive any other specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Departamento de Ingeniería Química, Química Física y Ciencias de los Materiale

Phytotoxins from Tithonia diversifolia

Tithonia diversifolia (Mexican sunflower) is a dominant plant of the Asteraceae family, which suggests it produces allelochemicals that interfere with the development of surrounding plants. The study described herein was conducted to identify the compounds that have phytotoxic activity in T. diversifolia extracts. Ethyl acetate extracts of the leaves, stems, and roots showed significant inhibition of wheat coleoptile growth, and the leaf extract had similar inhibitory effects to a commercial herbicide. Fourteen compounds, 12 of which were sesquiterpene lactones, have been isolated. Two sesquiterpene lactones are reported for the first time and were isolated as an inseparable mixture of 8β-O-(2-methylbutyroyl)- tirotundin (4) and 8β-O-(isovaleroyl)tirotundin (5). Their structures were determined by spectroscopic analysis, including NMR techniques and mass spectrometry. The sesquiterpene lactones 1β methoxydiversifolin (6), tagitinin A (7), and tagitinin C (8) were the major products identified. These compounds were active on etiolated wheat coleoptiles, seed germination, and the growth of STS and weeds. The phytotoxic activity shown by these sesquiterpene lactones indicates that they are the compounds responsible for the activity exhibited by the initial extracts

Composición y diversidad de peces del río San Pedro, Balancán, Tabasco, México

In the San Pedro river sub-basin, Balancán, Tabasco, Mexico, an ichthyofauna study was carried out in two subsystems; the main stream and the floodplain during the months of March 2007 to February 2008. From a total of 1035 fish were collected, 33 species, 25 genera and 14 families were identified. The Cichlidae and Poeciliidae family were the most species; four species are introduced Pterygoplichthys pardalis, Ctenopharyngodon idella, Oreochromis niloticus, Parachromis managuensis and two new records were found: P. pardalis and Potamarius usumacintae. The most abundance species were Thorichthys affinis and T. helleri and five species were least abundant: P. usumacintae, Phallichthys fairweatheri, Cichlasoma Nandopsis urophthalmus, C. idella and Batrachoides goldmani. The higher values of diversity and abundance showed in sites I (H=2.52 bits) and II (?=0.38 sp/ind). The higher values of evenness were in sites III (J = 0.86) and IV (J = 0.99). The abundance (Nmax = 353) species was showed in the site II. Significant differences (p<0.05) were found between the diversity and sites comparison. Canonical correspondence analysis showed that the temperature, dissolved oxygen and depth are the most important factors in the distribution of species. Finally, the relative abundance of species in the two seasons was representative by two families; Cichlidae T. affinis, (T. helleri and Petenia splendida) and Characidae(Astyanax aeneus).En la subcuenca del río San Pedro, Balancán, Tabasco, México, se realizó un estudio ictiofaunístico en dos subsistemas; el cauce principal del río y la zona de inundación en la parte baja, durante los meses de marzo 2007 a febrero 2008. De un total de 1,035 peces capturados, se identificaron 33 especies, 25 géneros y 14 familias. La familia Cichlidae y Poeciliidae fueron las más diversas, cuatro especies son introducidas: Pterygoplichthys pardalis, Ctenopharyngodon idella, Oreochromis niloticus, Parachromis managuensis, dos son nuevos registros Potamarius usumacintae y P. pardalis. Las especies más abundantes fueron Thorichthys affinis y T. helleri, mientras que P. usumacintae, Phallichthys fairweatheri, Cichlasoma Nandopsis urophthalmus, C. idella y Batrachoides goldmani, fueron las menos abundantes. La diversidad ydominancia presentaron valores altos en los sitios I (H´=2.52 bits) y el sitio II (? =0.38 sp/ind), mientras que los sitios III (J´=0.86) y IV (J´=0.99) fueron más equitativos. La especie más abundante (Nmax= 353) se mostró en el sitio II. Se encontró diferencias significativas (p < 0.5) entre la comparación de la diversidad y sitios. El análisis de correspondencia canónica, mostró que la temperatura, el oxígeno disuelto y la profundidad son los factores más importantes en la distribución de las especies. Finalmente, se encontró que las abundancias relativas de las especies presentes en las dos épocas estuvo representadas por dos familias; Cichlidae (T. affinis, T. helleri, Petenia splendida) y Characidae con (Astyanax aeneus)

Keys to the success of the CB Conquero

Cuando un club consigue éxitos deportivos a nivel profesional, existe un gran interés por investigar cuales han sido los factores claves de ese éxito. En esta investigación, se pretende analizar la influencia de diferentes factores como el contexto deportivo, el contexto social y aspectos del entrenamiento deportivo en el éxito del Club Baloncesto Conquero a través de la percepción de 13 informantes clave por su vinculación con el equipo y con el baloncesto onubense. Se realizó una entrevista, relacionada con los factores y las claves del éxito. Los resultados mostraron que la planificación de la plantilla junto al gran trabajo del cuerpo técnico, cuerpo médico y el preparador físico han sido las claves para que el club obtuviera los éxitos deportivos.When a team gets sport successes to level profesional, generates the topics that will be investigated such as the key factors of the succes. The main aim of this study is to analyze the influencie of different factors like the sports context, the social context and training aspects in the success of the Club Baloncesto Conquero through direct perception of thirteen informants associated with the team and the basketball in Huelva. An interview was carried out, related with those factors and the keys to success. The results revealed that workforce planning along the great work of coaching staff, medical staff and physical trainer have been key to the team gets sport successes