Microplastics can be present in the environment as manufactured microplastics (known as primary microplastics) or resulting from the continuous weathering of plastic litter, which yields ...progressively smaller plastic fragments (known as secondary microplastics). Herein, we discuss the numerous issues associated with the analysis of microplastics, and to a less extent of nanoplastics, in environmental samples (water, sediments, and biological tissues), from their sampling and sample handling to their identification and quantification. The analytical quality control and quality assurance associated with the validation of analytical methods and use of reference materials for the quantification of microplastics are also discussed, as well as the current challenges within this field of research and possible routes to overcome such limitations.
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•Microplastics have been identified as environmental pollutants.•The sampling, sample handling, identification and quantification of microplastics were discussed.•The validation of analytical methods and use of reference materials for the microplastics quantification were highlighted.•The current challenges in these issues are identified.
Heat transfer and thermal properties at the nanoscale can be challenging to obtain experimentally. These are potentially relevant for understanding thermoregulation in cells. Experimental data from ...the transient heating regime in conjunction with a model based on the energy conservation enable the determination of the specific heat capacities for all components of a nanoconstruct, namely an upconverting nanoparticle and its conformal lipid bilayer coating. This approach benefits from a very simple, cost-effective and non-invasive optical setup to measure the thermal parameters at the nanoscale. The time-dependent model developed herein lays the foundation to describe the dynamics of heat transfer at the nanoscale and were used to understand the heat dissipation by lipid bilayers.
Luminescent nanomaterials have shown promise for thermal sensing in bio‐applications, yet little is known of the role of organic coatings such as supported lipid bilayers on the thermal conductivity ...between the nanomaterial and its environment. Additionally, since the supported lipid bilayer mimics the cell membrane, its thermal properties are fundamentally important to understand the spatial variations of temperature and heat transfer across membranes. Herein, a new approach is described that enables direct measurement of these thermal properties using a LiYF4:Er3+/Yb3+ upconverting nanoparticle encapsulated within a conformal supported lipid bilayer and dispersed in water as a temperature probe yielding the temperature gradient across the bilayer. The thermal conductivity of the lipid bilayer is measured as a function of the temperature, being 0.20 ± 0.02 W m−1 K−1 at 300 K. For the uncapped nanoparticles dispersed in water, the temperature dependence of the thermal conductivity is also measured in the 300–314 K range as 0.63–0.69 ± 0.11 W m−1 K−1. Using a lumped elements model, the directional heat transfer is calculated at each of the system interfaces, namely, nanoparticle–bilayer and bilayer–nanofluid, opening a new avenue to understand the membrane biophysical properties as well as the thermal properties of organic and polymer coatings.
The thermal properties of organic coatings on inorganic nanoparticles, for example biomimetic lipid bilayers, play a key role in their application as intracellular temperature probes. Measuring the core temperature using upconversion thermometry enables direct determination of the bilayer thermal conductivity, opening avenues for studying fundamental membrane biophysical and thermal properties of organic and polymer coatings for a multitude of nanomaterials.
With accumulation of carbon cycle observations and model developments over the past decades, exploring interannual variation (IAV) of terrestrial carbon cycle offers the opportunity to better ...understand climate–carbon cycle relationships. However, despite growing research interest, uncertainties remain on some fundamental issues, such as the contributions of different regions, constituent fluxes and climatic factors to carbon cycle IAV. Here we overviewed the literature on carbon cycle IAV about current understanding of these issues. Observations and models of the carbon cycle unanimously show the dominance of tropical land ecosystems to the signal of global carbon cycle IAV, where tropical semiarid ecosystems contribute as much as the combination of all other tropical ecosystems. Vegetation photosynthesis contributes more than ecosystem respiration to IAV of the global net land carbon flux, but large uncertainties remain on the contribution of fires and other disturbance fluxes. Climatic variations are the major drivers to the IAV of net land carbon flux. Although debate remains on whether the dominant driver is temperature or moisture variability, their interaction,that is, the dependence of carbon cycle sensitivity to temperature on moisture conditions, is emerging as key regulators of the carbon cycle IAV. On timescales from the interannual to the centennial, global carbon cycle variability will be increasingly contributed by northern land ecosystems and oceans. Therefore, both improving Earth system models (ESMs) with the progressive understanding on the fast processes manifested at interannual timescale and expanding carbon cycle observations at broader spatial and longer temporal scales are critical to better prediction on evolution of the carbon–climate system.
Interannual variation (IAV) of global carbon cycle is dominated by terrestrial ecosystems, in particular the tropics. Thus, understanding IAV of carbon cycle improves our knowledge on how tropical land ecosystems respond to climatic variations. However, global carbon cycle variability will be increasingly contributed by northern land ecosystems and oceans on timescales from the interannual to the centennial. This highlights the research need to integrate knowledge on “fast” carbon cycle processes, which can be learned from IAV, and those on “slow” carbon processes over both land and ocean, in order to better predict evolution of the carbon–climate system.
Both low soil water content (SWC) and high atmospheric dryness (vapor pressure deficit, VPD) can negatively affect terrestrial gross primary production (GPP). The sensitivity of GPP to soil versus ...atmospheric dryness is difficult to disentangle, however, because of their covariation. Using global eddy-covariance observations, here we show that a decrease in SWC is not universally associated with GPP reduction. GPP increases in response to decreasing SWC when SWC is high and decreases only when SWC is below a threshold. By contrast, the sensitivity of GPP to an increase of VPD is always negative across the full SWC range. We further find canopy conductance decreases with increasing VPD (irrespective of SWC), and with decreasing SWC on drier soils. Maximum photosynthetic assimilation rate has negative sensitivity to VPD, and a positive sensitivity to decreasing SWC when SWC is high. Earth System Models underestimate the negative effect of VPD and the positive effect of SWC on GPP such that they should underestimate the GPP reduction due to increasing VPD in future climates.
This book explores the diverse landscapes wherein women struggle for their personal and social identities and lives, between biology and culture, destiny and choice, shared and individual worlds, ...tradition and modernity. Their "peripheral lives" have "central meaning" (Chaudhary, this volume) in any society - and as such are approached as a primary subject in this book, as the chapters traverse ten different countries on three continents: North America (United States); Latin America (Brazil, Chile, Colombia); Asia (India); and Europe (United Kingdom, Ireland, Portugal, Finland, Estonia).Throughout these different places, women's lives are an interesting stage for observing the interaction between biology and culture (e.g. sex vs. gender; pregnancy and childbirth vs. transition to motherhood). The focus on the cultural variability of human experience opens the door for the search of commonalities so needed in psychological theorizing. Here, this search is directed by how cultural models of womanhood (and motherhood) constrain personal experiences, especially through developmental transitions.This book is, ultimately, an opportunity to approach women's lives from the perspective of the women themselves, particularly making audible and explicit their voices and the axis of logic that structures their world. Undoubtedly, it is a valuable opportunity for women and men interested in understanding and constructing human experience inside better worlds.
Bone tissue engineering approaches have evolved towards addressing the challenges of tissue mimetic requirements over the years. Different strategies have been combining scaffolds, cells, and ...biologically active cues using a wide range of fabrication techniques, envisioning the mimicry of bone tissue. On the one hand, biomimetic scaffold-based strategies have been pursuing different biomaterials to produce scaffolds, combining with diverse and innovative fabrication strategies to mimic bone tissue better, surpassing bone grafts. On the other hand, biomimetic scaffold-free approaches mainly foresee replicating endochondral ossification, replacing hyaline cartilage with new bone. Finally, since bone tissue is highly vascularized, new strategies focused on developing pre-vascularized scaffolds or pre-vascularized cellular aggregates have been a motif of study. The recent biomimetic scaffold-based and scaffold-free approaches in bone tissue engineering, focusing on materials and fabrication methods used, are overviewed herein. The biomimetic vascularized approaches are also discussed, namely the development of pre-vascularized scaffolds and pre-vascularized cellular aggregates.
•Bone tissue engineering approaches envision to mimic tissue requirements.•Biodegradable materials, cells, and biologically active cues have been combined using different techniques to reach such requirements.•Recent biomimetic scaffold-based and scaffold-free strategies aiming for bone tissue engineering are overviewed herein.•Also, biomimetic vascularized approaches are discussed.
There is evidence that poverty, health and nutrition affect children's cognitive development. This study aimed to examine the relative contributions of both proximal and distal risk factors on child ...cognitive development, by breaking down the possible causal pathways through which poverty affects cognition.
This cohort study collected data on family socioeconomic status, household and neighbourhood environmental conditions, child health and nutritional status, psychosocial stimulation and nursery school attendance. The effect of these on Wechsler Pre-School and Primary Scale of Intelligence scores at five years of age was investigated using a multivariable hierarchical analysis, guided by the proposed conceptual framework.
Unfavourable socioeconomic conditions, poorly educated mother, absent father, poor sanitary conditions at home and in the neighbourhood and low birth weight were negatively associated with cognitive performance at five years of age, while strong positive associations were found with high levels of domestic stimulation and nursery school attendance.
Children's cognitive development in urban contexts in developing countries could be substantially increased by interventions promoting early psychosocial stimulation and preschool experience, together with efforts to prevent low birth weight and promote adequate nutritional status.
The leather industry produces a large quantity of solid waste (wet blue leather), which contains a high amount of chromium. After its removal from wet blue leather, a solid collagenic material is ...recovered, containing high nitrogen levels, which can be used as a nitrogen source in agriculture. In order to take more advantage of the collagen, it was enriched with mineral P and K in order to produce NPK formulations. The objective was also to evaluate the efficiency of such formulations as a nutrient supply for rice plants in an Oxisoil, under greenhouse conditions. The application of PK enriched-collagen formulations resulted in N contents in the vegetative parts and grains of rice plants which were equivalent or superior to those obtained with urea and commercial NPK formulations.
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