Antibubbles enable tunable payload release with low-intensity ultrasound

The benefits of ultrasound are its ease-of-use and its ability to precisely deliver energy in opaque and complex media. However, most materials responsive to ultrasound show a weak response, requiring the use of high powers, which are associated with undesirable streaming, cavitation, or temperature rise. These effects hinder response control and may even cause damage to the medium where the ultrasound is applied. Moreover, materials that are currently in use rely on all-or-nothing effects, limiting the ability to fine-tune the response of the material on the fly. For these reasons, there is a need for materials that can respond to low intensity ultrasound with programmable responses. Here it is demonstrated that antibubbles are a low-intensity-ultrasound-responsive material system that can controllably release a payload using acoustic pressures in the kPa range. Varying their size and composition tunes the release pressure, and the response can be switched between a single release and stepwise release across multiple ultrasound pulses. Observations using confocal and high-speed microscopy revealed different ways that can lead to release. These findings lay the groundwork to design antibubbles that controllably respond to low-intensity ultrasound, opening a wide range of applications ranging from ultrasound-responsive material systems to carriers for targeted delivery.Comment: Main Text: 14 pages, 4 figures. Embedded SI: 4 pages, 5 figure

The muscle-bone unit in adolescent swimmers

Most researchers adjust bone by lean mass when comparing swimmers with controls. This adjustment is done under the assumption that lean affects bone similarly in both groups. Nonetheless, we found that the muscle-bone association is uncoupled in swimmers, and consequently, researchers should avoid this adjustment when evaluating swimmers’ bone. Introduction: To examine the functional and structural muscle-bone unit in adolescent swimmers. Methods: Sixty-five swimmers (34 girls/31 boys) and 119 controls (51 girls/68 boys) participated in the study. Muscle cross-sectional area (MCSA), bone mineral content (BMC), and polar strength-strain index (SSIPOL) were measured in the non-dominant radius by peripheral quantitative computed tomography (pQCT). Subtotal BMC and lean mass were evaluated with dual-energy X-ray absorptiometry (DXA). Handgrip and isometric knee extension (IKE) tests were performed to determine muscle force. The effect of MCSA, lean and force on SSIPOL, and BMC were tested, and the functional and structural muscle-bone ratios of swimmers and controls were compared. Results: Both muscle size (MCSA and lean) and muscle force (handgrip and IKE) influenced BMC and SSIPOL in swimmers and controls similarly. Swimmers presented normal MCSA and lean values for their height, but when compared with controls, swimmers presented a higher amount of lean and MCSA for the same BMC or SSIPOL (structural muscle-bone unit). For the functional muscle-bone unit, different results were found for the lower and upper limbs, as no differences were found for the upper limbs, while for the lower limbs, swimmers presented higher muscle force for the same amount of BMC. Conclusions: The contradictory results regarding BMC in swimmers found in previous studies could partly be explained with the findings of the present study that reinforce the idea that swimming is not an effective sport to practice regarding bone mass and that the muscle-bone unit is different in swimmers than in controls

Crosslinked electrospun zein-based food packaging coatings containing bioactive chilto fruit extracts

peer-reviewedIn this work, zein fibers loaded with phenolic-enriched extracts from pulp, seed and skin of orange chilto were collected on polyhydroxyalkanoate (PHA) films through the electrospinning technique, for their potential use as bioactive internal coatings for food packaging applications. The zein fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The water stability of the zein fibers was improved by crosslinking with glutaraldehyde vapors. The encapsulation efficiency of all bioactive phenolic-enriched extracts was greater than 90%. Encapsulation in the zein fibers improved the thermostability of the extracts. Two food simulants (50% ethanol and 3% acetic acid) were used to evaluate the release of the extracts from the crosslinked zein fibers. It was observed that crosslinking delayed the release of phenolic compounds (rosmarinic acid, caffeic acid and its derivates) in both solvents (80% released after 7 days of contact in 50% ethanol and 23 days in 3% acetic acid) and their antioxidant properties were kept. Therefore, this work demonstrates the potential of the developed zein-based encapsulation structures containing chilto extracts to be applied as antioxidant coatings in food packaging structures to contribute to the preservation of both hydrophilic and lipophilic food products

Lower Cretaceous (Hauterivian-Albian) ammonite biostratigraphy in the Maestrat Basin (E Spain)

Peer reviewedPublisher PD

Probiotics and trained immunity

The characteristics of innate immunity have recently been investigated in depth in several research articles, and original findings suggest that innate immunity also has a memory capacity, which has been named “trained immunity”. This notion has revolutionized our knowledge of the innate immune response. Thus, stimulation of trained immunity represents a therapeutic alternative that is worth exploring. In this context, probiotics, live microorganisms which when administered in adequate amounts confer a health benefit on the host, represent attractive candidates for the stimulation of trained immunity; however, although numerous studies have documented the beneficial proprieties of these microorganisms, their mechanisms of action are not yet fully understood. In this review, we propose to explore the putative connection between probiotics and stimulation of trained immunity.Fil: Cortes Peres, Naima G.. Institut National de la Recherche Agronomique; FranciaFil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Gomez Gutierrez, Jorge G.. University of Missouri; Estados UnidosFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Bermúdez Humarán, Luis G.. Institut National de la Recherche Agronomique; Franci

Lesson from the habitat suitability models to evaluate the environmental of Pinus nigra Arnold and Pinus sylvesris L. in the Iberian Peninsula

PREDICT POTENTIAL DISTRIBUTION. Spatial and temporal evolution of the species under different climate scenarios. Generation of habitat suitability models (HSM) high degree of uncertainty and limitations. The importance of their validation has been stressed. In this work we discuss the present potential distribution of P. sylvestris and P. nigra in the Iberian Peninsula by using MaxEnt, and evaluate the influence of the different environmental variables. Our intention is to select a set of environmental variables that explains better their current distribution, to achieve the most accurate and reliable models. Then we project them to the past climatic conditions (21 to 0 kyrs BP), to evaluate the outputs with existing palaeo-ecological data

Mechanical properties of freely suspended atomically thin dielectric layers of mica

We have studied the elastic deformation of freely suspended atomically thin sheets of muscovite mica, a widely used electrical insulator in its bulk form. Using an atomic force microscope, we carried out bending test experiments to determine the Young's modulus and the initial pre-tension of mica nanosheets with thicknesses ranging from 14 layers down to just one bilayer. We found that their Young's modulus is high (190 GPa), in agreement with the bulk value, which indicates that the exfoliation procedure employed to fabricate these nanolayers does not introduce a noticeable amount of defects. Additionally, ultrathin mica shows low pre-strain and can withstand reversible deformations up to tens of nanometers without breaking. The low pre-tension and high Young's modulus and breaking force found in these ultrathin mica layers demonstrates their prospective use as a complement for graphene in applications requiring flexible insulating materials or as reinforcement in nanocomposites.Comment: 9 pages, 5 figures, selected as cover of Nano Research, Volume 5, Number 8 (2012

Femtosecond laser microstructuring of zirconia dental implants

This study evaluated the suitability of femtosecond laser for microtexturizing cylindrical zirconia dental implants surface. Sixty-six cylindrical zirconia implants were used and divided into three groups: Control group (with no laser modification), Group A (microgropored texture), and Group B (microgrooved texture). Scanning electron microscopy observation of microgeometries revealed minimal collateral damage of the original surface surrounding the treated areas. Optical interferometric profilometry showed that ultrafast laser ablation increased surface roughness (Ra, Rq, Rz, and Rt) significantly for both textured patterns from 1.2× to 6×-fold when compared with the control group (p Group B 8.4% ± 0.42% > Group A 1.6% ± 0.35%) and aluminum (Control 4.3% ± 0.9% > Group B 2.3% ± 0.3% > Group A 1.16% ± 0.2%) in the laser-treated surfaces (p Group A 1.94% > Group B 1.72%) as the surfaces were processed with ultrashort laser pulses. We concluded that femtosecond laser microstructuring offers an interesting alternative to conventional surface treatments of zirconia implants as a result of its precision and minimal damage of the surrounding areas