Modelling the effect of vertical mixing on bottle incubations for determining in situ phytoplankton dynamics. I. Growth rates

Reliable estimates of in situ phytoplankton growth rates are central to understanding the dynamics of aquatic ecosystems. A common approach for estimating in situ growth rates is to incubate natural phytoplankton assemblages in clear bottles at fixed depths or irradiance levels and measure the change in chlorophyll a (Chl) over the incubation period (typically 24 h). Using a modelling approach, we investigate the accuracy of these Chl-based methods focussing on 2 aspects: (1) in a freely mixing surface layer, the cells are typically not in balanced growth, and with photoacclimation, changes in Chl may yield different growth rates than changes in carbon; and (2) the in vitro methods neglect any vertical movement due to turbulence and its effect on the cells' light history. The growth rates thus strongly depend on the incubation depth and are not necessarily representative of the depth-integrated in situ growth rate in the freely mixing surface layer. We employ an individual based turbulence and photosynthesis model, which also accounts for photoacclimation and photo - inhibition, to show that the in vitro Chl-based growth rate can differ both from its carbon-based in vitro equivalent and from the in situ value by up to 100%, depending on turbulence intensity, optical depth of the mixing layer, and incubation depth within the layer. We make recommendations for choosing the best depth for single-depth incubations. Furthermore we demonstrate that, if incubation bottles are being oscillated up and down through the water column, these systematic errors can be significantly reduced. In the present study, we focus on Chl-based methods only, while productivity measurements using carbon-based techniques (e.g. 14C) are discussed in Ross et al. (2011; Mar Ecol Prog Ser 435:33-45). © Inter-Research 2011

Estimating underwater light diffuse attenuation with low-cost devices: optimal sensor configuration analysis using radiative transfer models

Peer Reviewe

Photopolymerized thermosensitive poly(HPMAlactate)-PEG-based hydrogels : effect of network design on mechanical properties, degradation, and release behavior

Photopolymerized thermosensitive A-B-A triblock copolymer hydrogels composed of poly(N-(2-hydroxypropyl)-methacrylamide lactate) A-blocks, partly derivatizal with methacrylate groups to different extents (10, 20, and 30%) and hydrophilic poly(ethylene glycol) B-blocks of different molecular weights (4, 10, and 20 kDa) were synthesized. The aim of the present study was to correlate the polymer architecture with the hydrogel properties, particularly rheological, swelling, degradation properties and release behavior. It was found that an increasing methacrylation extent and a decreasing PEG molecular weight resulted in increasing gel strength and cross-link density, which tailored the degradation profiles from 25 to more than 300 days. Polymers having small PEG blocks showed a remarkable phase separation into polymer- and water-rich domains, as demonstrated by confocal microscopy. Depending on the hydrophobic domain density, the loaded protein resides in the hydrophilic pores or is partitioned into hydrophilic and hydrophobic domains, and its release from these compartments is tailored by the extent of methacrylation and by PEG length, respectively. As the mechanical properties, degradation, and release profiles can be fully controlled by polymer design and concentration, these hydrogels are suitable for controlled protein release

Synthesis of layered titanosilicate JDF-L1 for fabrication of composite polyamide 6 film

In clay polymer nanocomposite technology, nowadays there is concern about the safety and environmental effects of the nanometric materials. In this work, sheets of layered titanosilicate JDF-L1 were synthesized with a size of 5.3 µmand thickness of 115 nm and used to fabricate composite polyamide 6 (PA6) films. The JDF-L1 synthesis was scaled in one pot and the rosette-like particles obtained were disaggregated using a simple process with NaOH solution. The composite with 2 wt.% of disaggregated JDF-L1, characterized by X-ray diffraction and electron microscopy, showed parallel orientation (with respect to the film itself) and good dispersion of the sheets. The composite had a similar barrier effect as the PA6 and its mechanical properties did not deteriorate. This opens up the use of this composite as a packing material providing other properties, such as a biocidal effect and synergy effect in combination with other additives

Antibacterial activity of matrix-bound ovotransferrin

Ovotransferrin immobilized by covalent linkage to Sepharose 4B showed a bacteriostatic effect towards Escherichia coli similar to that of free ovotransferrin. The growth of the bacteria, after exposure to the gel-bound ovotransferrin and its removal, depended on the length of exposure. The results suggest that the antibacterial activity of transferrin is not due simply to the removal of iron from the medium

Chronic obstructive pulmonary disease (COPD) and occupational exposures

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality in both industrialized and developing countries. Cigarette smoking is the major risk factor for COPD. However, relevant information from the literature published within the last years, either on general population samples or on workplaces, indicate that about 15% of all cases of COPD is work-related. Specific settings and agents are quoted which have been indicated or confirmed as linked to COPD. Coal miners, hard-rock miners, tunnel workers, concrete-manufacturing workers, nonmining industrial workers have been shown to be at highest risk for developing COPD. Further evidence that occupational agents are capable of inducing COPD comes from experimental studies, particularly in animal models. In conclusion, occupational exposure to dusts, chemicals, gases should be considered an established, or supported by good evidence, risk factor for developing COPD. The implications of this substantial occupational contribution to COPD must be considered in research planning, in public policy decision-making, and in clinical practice

Combined use of x-ray fluorescence microscopy, phase contrast imaging for high resolution quantitative iron mapping in inflamed cells

X-ray fluorescence microscopy (XRFM) is a powerful technique to detect and localize elements in cells. To derive information useful for biology and medicine, it is essential not only to localize, but also to map quantitatively the element concentration. Here we applied quantitative XRFM to iron in phagocytic cells. Iron, a primary component of living cells, can become toxic when present in excess. In human fluids, free iron is maintained at 10-18 M concentration thanks to iron binding proteins as lactoferrin (Lf). The iron homeostasis, involving the physiological ratio of iron between tissues/secretions and blood, is strictly regulated by ferroportin, the sole protein able to export iron from cells to blood. Inflammatory processes induced by lipopolysaccharide (LPS) or bacterial pathoge inhibit ferroportin synthesis in epithelial and phagocytic cells thus hindering iron export, increasing intracellular iron and bacterial multiplication. In this respect, Lf is emerging as an important regulator of both iron and inflammatory homeostasis. Here we studied phagocytic cells inflamed by bacterial LPS and untreated or treated with milk derived bovine Lf. Quantitative mapping of iron concentration and mass fraction at high spatial resolution is obtained combining X-ray fluorescence microscopy, atomic force microscopy and synchrotron phase contrast imaging

Caffeine Encapsulation in Metal Organic Framework MIL-53(Al) at Pilot Plant Scale for Preparation of Polyamide Textile Fibers with Cosmetic Properties

Currently in the marketplace, we can find clothing items able to release skin-friendly ingredients while wearing them. These innovative products with high-added value are based on microencapsulation technology. In this work, due to its lightness, flexibility, porosity, chemical affinity and adsorption capacity, metal-organic framework (MOF) MIL-53(Al) was the selected microcapsule to be synthesized at a large scale and subsequent caffeine encapsulation. The synthesis conditions (molar ratio of reactants, solvents used, reaction time, temperature, pressure reached in the reactor and activation treatment to enhance the encapsulation capacity) were optimized by screening various scaling-up reactor volumes (from lab-scale of 40 mL to pilot plant production of 3.75 L). Two types of Al salts (Al(NO3)3·9H2O from the original recipe and Al2(SO4)3 as commercial SUFAL 8.2) were employed. The liporeductor cosmetic caffeine was selected as the active molecule for encapsulation. Caffeine (38 wt %) was incorporated in CAF@MIL-53(Al) microcapsules, as analyzed by TGA and corroborated by GC/MS and UV-vis after additive extraction. CAF@MIL-53(Al) microcapsules showed a controlled release of caffeine during 6 days at 25 °C (up to 22% of the initial caffeine). These capsules were incorporated through an industrial spinning process (with temperatures up to 260 °C) to manufacture PA-6 fibers with cosmetic properties. Up to 0.7 wt % of capsules were successfully incorporated into the fibers hosting 1700 ppm of caffeine. Fabrics were submitted to scouring, staining, and washing processes, detecting the presence of caffeine in the cosmetic fiber. © 2022 The Authors. Published by American Chemical Society

Parental Relationship with Twins from Pregnancy to 3 Months: The Relation Among Parenting Stress, Infant Temperament, and Well-Being

Objective: The transition to parenthood, from pregnancy to postpartum period, is a critical process, particularly for couples expecting twins. There is very little literature regarding the links between anxiety, depression, dyadic adjustment, parental stress, and infant temperament spanning from pregnancy to postpartum. This study has two aims: first, to examine whether mothers' and fathers' anxiety, depression, and dyadic adjustment, assessed at the sixth month of pregnancy and 3 months postpartum, are associated with infants' negative affectivity (NA) and parenting stress; second, to examine whether there is any difference between fathers' and mothers' levels of parenting stress and perception of the twins' temperament, as well as to evaluate, separately for mothers and fathers, whether the levels of parenting stress and perception of child temperament differ for each twin. Method: The study participants were 58 parents (29 couples) and their healthy 58 twin babies (51.7% boys, 48.3% girls). Mothers' ages ranged from 30 to 44 years, (M Age = 36.3 years, SD = 3.2 years), and fathers' ages ranged from 32 to 52 years, (M Age = 38.2 years, SD = 4.4 years). The parents, during the pregnancy period and 3 months after delivery, filled out the Edinburgh Postnatal Depression Scale, the State-Trait Anxiety Inventory, and the Dyadic Adjustment Scale. Three months after delivery they also filled out the Parenting Stress Index-Short Form and the Infant Behavior Questionnaire Revised. Results: The analyses showed a significant correlation between parental anxiety/depression symptoms and infants' NA and parenting stress (in both mothers and fathers). Moreover, compared to fathers, mothers reported higher scores on specific dimensions of the infants' NA, [t(28)= -2.62 and p < 0.05; t(28) = 2.09 and p < 0.05], and parenting stress, [t(28) = 2.19 and p < 0.05; t(28) = 2.23 and p < 0.05], but only for Twin 2. Finally, the results showed that mothers' perceptions of child temperament vary between two twins, [e.g., distress to limitations: t(28) = 2.08 and p < 0.05]. Discussion: This study highlights the peculiarity of twin parenthood during the fourth trimester. In particular, the differences between twins' mothers' and fathers' perceptions are relevant from a clinical perspective and for perinatal professionals. It would be interesting to study the long-term impact of mothers' and fathers' differing perceptions of their twins