The Role of Cytokinins during the Development of Strawberry Flowers and Receptacles.

Cytokinins play a relevant role in flower and fruit development and plant yield. Strawberry fruits have a high commercial value, although what is known as the "fruit" is not a "true" botanical fruit because it develops from a non-reproductive organ (receptacle) on which the true botanical fruits (achenes) are found. Given cytokinins' roles in botanical fruits, it is important to understand their participation in the development of a non-botanical or accessory "fruit". Therefore, in this work, the role of cytokinin in strawberry flowers and fruits was investigated by identifying and exploring the expression of homologous genes for different families that participate in the pathway, through publicly available genomic and expression data analyses. Next, trans-zeatin content in developing flowers and receptacles was determined. A high concentration was observed in flower buds and at anthesis and decreased as the fruit approached maturity. Moreover, the spatio-temporal expression pattern of selected CKX genes was evaluated and detected in receptacles at pre-anthesis stages. The results point to an important role and effect of cytokinins in flower and receptacle development, which is valuable both from a biological point of view and to improve yield and the quality of this fruit.

Analysis of the Microstructure and Porosity of Cement Pastes with Functionalized Nanosilica with Different Contents of Aminosilane.

This research aims to analyze the effect of functionalized nanosilica (NSF) with different levels of amine groups in the formation of hydration products. Four cement pastes were investigated, one reference with Portland cement and three replacing 1% of Portland cement by nanosilica (NS), NSF with a low content of amine groups, and NSF with a high content of amine groups. The heat of hydration of the pastes was evaluated up to 7 days of hydration, the amount of calcium hydroxide (CH) and hydrated phases by means of the thermogravimetric analysis (TGA) test and compressive strength at 2, 7, and 28 days, and porosity through tests of mercury intrusion porosimetry and computed tomography at 28 days of hydration. It was possible to observe that the NSF directly influenced the hydration kinetics of the pastes, delaying the hydration of the Portland cement; however, it demonstrated a similar mechanical performance to the paste with NS at 2 days of hydration and an increase of 10% at 28 days of hydration due to the improvement in the hydration process. Thus, it is possible to conclude that the functionalization of NSF with a low 3-aminopropyltriethoxysilane (APTES) content is promising for use in cementitious materials and may improve hydration and mechanical performance at more advanced ages compared to NS.

Biopolymer-Based Composite Hydrogels Embedding Small Silver Nanoparticles for Advanced Antimicrobial Applications: Experimental and Theoretical Insights.

In this work, we report a two-step methodology for the synthesis of small silver nanoparticles embedded into hydrogels based on chitosan (CS) and hydroxypropyl methylcellulose (HPMC) biopolymers. This method uses d-glucose as an external green reducing agent and purified water as a solvent, leading to an eco-friendly, cost-effective, and biocompatible process for the synthesis of silver nanocomposite hydrogels. Their characterization comprises ultraviolet-visible spectroscopy, Fourier-transform infrared spectra, differential scanning calorimetry, scanning electron microscopy with energy-dispersive spectroscopy, and transmission electron microscopy assays. Moreover, the structural stability of the hydrogels was investigated through sequential swelling-deswelling cycles. The nanomaterials showed good mechanical properties in terms of their structural stability and revealed prominent antibacterial properties due to the reduced-size particles that promote their use as new advanced antimicrobial agents, an advantage compared to conventional particles in aqueous suspension that lose stability and effectiveness. Finally, theoretical analyses provided insights into the possible interactions, charge transfer, and stabilization process of nanoclusters mediated by the high-electron-density groups belonging to CS and HPMC, revealing their unique structural properties in the preparation of nano-scaled materials.

Physical and Chemical Effects in Blended Cement Pastes Elaborated with Calcined Clay and Nanosilica.

Supplementary cementitious materials (SCMs) are commonly used in the manufacture of commercial cements with lower clinker content and carbon footprints, enabling environmental and performance improvements. The present article evaluated a ternary cement combining 23% calcined clay (CC) and 2% nanosilica (NS) to replace 25% of the Ordinary Portland Cement (OPC) content. For this purpose, a series of tests were performed, such as compressive strength, isothermal calorimetry, thermogravimetry (TG/DTG), X-ray diffraction (XDR), and mercury intrusion porosimetry (MIP). The ternary cement studied, 23CC2NS, presents a very high surface area, which influences hydration kinetics by accelerating silicate formation and causes an undersulfated condition. The pozzolanic reaction is potentialized by the synergy between the CC and NS, resulting in a lower portlandite content at 28 days in the 23CC2NS paste (6%) compared with the 25CC paste (12%) and 2NS paste (13%). A significant reduction in total porosity and conversion of macropores in mesopores was observed. For example, 70% of pores in OPC paste were macropores that were converted in the 23CC2NS paste into mesopores and gel pores.

Reactivity of Binary Construction and Demolition Waste Mix as Supplementary Cementitious Materials.

Calcareous and siliceous CDW wastes from concrete and glass wastes when mixed in binary mixtures has been analyzed in this study. Fine CDW fractions (<5 mm) of different sorts are selected: siliceous waste (HsT), calcareous waste (HcG) and laminated glass waste. The binary mixtures HsT/glass and HcG/glass at mix-proportions of 1:1, 2:1 and 1:2, respectively, are analyzed with a range of characterization techniques (XRD, TG/DTA, SEM-EDX, NMR, FT-IR) in the pure pozzolan/lime system over a reaction time of 90 days. The results showed that the incorporation of highly reactive recycled glass modified the pozzolanic reaction of the binary mixtures with respect to each particular concrete waste (of low activity). The principal mineralogical phases of the reaction were calcite and C-S-H gel, the latter modifying the C/S and A/S ratios as a function of either the silica or the lime-based concrete waste and the glass content of the mixtures. A higher degree of polymerization, morphology, and sodium content of C-H-S gel formed when glass was added.

Two coupled double quantum-dot systems as a working substance for heat machines.

This paper presents a conceptual design for quantum heat machines using a pair of coupled double quantum dots (DQDs), each DQD with an excess electron to interact, as an working substance. We define a compression ratio as the ratio between the Coulomb couplings which describes the interaction between the electrons during the isochoric processes of the quantum Otto cycle and then we analyze the arising of different regimes of operations of our thermal machine. We also show that we may change the operation mode of an Otto engine when considering the effects due to the quantum tunneling of a single electron between each individual DQD.

MALDI coupled to modified traveling wave ion mobility mass spectrometry for fast enantiomeric determination.

In this work, the use of MALDI traveling wave ion mobility spectrometry-mass spectrometry (MALDI-TWIMS-MS) for stereoselective structural analysis of direct cleavage and identification of 2-substituted piperidines obtained through solid-phase asymmetric synthesis by using heterogeneous 8-phenylmenthyl-based chiral auxiliary resins. A strategy for gas-phase chiral and structural characterization of small molecular weight molecules by using MALDI-IMS-MS technique is discussed. Because both MALDI and IMS do not directly offer chiral resolution, an easy methodology by adding a chiral phase is described to carry out in situ online ion/molecule complexation with different chiral analytes inside the mass spectrometer. Piperidine enantiomers were resolved, and separation obtained shows dependence of surface areas. To corroborate this assumption and elucidate the separation mechanism to accomplish an analytical technique by which fast determination of the chirality of molecules may be determined for a wide range organic compound applications, it was performed DFT calculations to determine the cross-sectional areas of proton-bound dimer complexes. Drift times are affected by cross-sectional areas, correlating bigger times with bigger molecular volumes during the ion mobility experiments of proton-bound dimer complexes.

THE PREVALENCE OF COLONIC POLYPS IN PATIENTS WITH ACROMEGALY: A CASE-CONTROL, NESTED IN A COHORT COLONOSCOPIC STUDY.

OBJECTIVE: Acromegaly is associated with an increased risk of colonic polyps. The magnitude of such risk is controversial, and the characteristics that distinguish patients who develop polyps from those who do not are not well established. This study was performed to determine the prevalence of colonic polyps upon the diagnosis of acromegaly and to compare the clinical and biochemical features of patients with and without polyps. METHODS: Out of 165 patients who underwent a full colonoscopy upon diagnosis of acromegaly, 53 were found to harbor colonic lesions (cases), whereas the remaining 112 were used as controls. Demographic, clinical, and biochemical characteristics were compared between the 2 groups. RESULTS: The prevalence of colonic polyps was 32%, with an estimated relative risk of 6.21 (95% confidence interval [CI] 4.08-9.48). Adenomatous and nonadenomatous polyps were found in 22 and 31 patients, respectively. The most common location was the descending colon. Compared to patients without polyps, subjects with polyps were somewhat older and had significantly higher insulin-like growth factor-1 (IGF-1) levels and a higher prevalence of diabetes. Upon multivariate analysis, only IGF-1 level at diagnosis remained significantly associated with colonic polyps in general and with hyperplastic polyps in particular. CONCLUSION: Acromegaly is associated with an elevated risk of developing colonic polyps, particularly, distally located hyperplastic lesions. Except for a higher IGF-1 level at diagnosis, no distinctive clinical or biochemical features can be found among those who develop polyps compared to those who do not. ABBREVIATIONS: CI = confidence interval GH = growth hormone IGF-1 = insulin-like growth factor 1 IQR = inter-quartile range RR = relative risk ULN = upper limit of normal.

Reunión Anual de Etnología 1995

Indice: Sociología Rural. La Fundación del pueblo de Taraqu. El Contexto Social en el Proceso de Reconstruccion de Suka-Qollu. Bajo Llojeta:Una manifestacion de los conflictos sociales rural-urbanos en materia de tierra y vivienda (1950-1994). La praxis de la educación indigenal de los liberales de principios del siglo XX. Reflexiones sociológicas sobre la enseñanza de la filosofía y una propuesta para el cambio. Folklore, Etnomusicología y Artes Populares. Renacimiento de la Saya: el rol que juega la música en el movimiento negro en Bolivia. Rescate y Defensa de los Valores Culturales en la Fiesta de San Bartolomé (1980-1994). Las bandas musicales Folklóricas de La Paz (nombres y denominaciones). Ayrachis del Sur de Bolivia (Un Primer Ensayo). La Feria de Alasitas. Un fenómeno de la cultura urbana moderna: Aproximación a la semiótica de la miniatura. Calendario anual de fiestas. La saya no es la saya. Decir la verdad para mentir. Organización territorial de Pacajes. La política estatal hacia los pueblos indígenas en el marco del nuevo orden territorial municipal. Participación popular en el centro y sudeste de Potosí:una visión panorámica de las organizaciones territoriales de base, OTBïs Perspectivas de los derechos interculturales en Bolivia. Apuntes para la discusión de una Ley Agraria Campesino-indigena Constituir un sistema orgánico de las diferencias nacional culturales. La Participación Popular en la cultura aymara quechua