Testing the Dispersion of Nanoparticles in a Nanocomposite with an Ultra-Low Fill Content Using a Novel Non-Destructive Evaluation Technique

A non-destructive evaluation (NDE) technique capable of testing the dispersion of nanoparticles in a nanocomposite would be of great use to the industry to check the quality of the products made and to ensure compliance with their specifications. Very few NDE techniques found in the literature can evaluate the level of dispersion of the nanoparticles in the whole nanocomposite. Here, a recently developed NDE technique based on pulsed phase thermography (PPT) in transmission mode was used to assess the particle dispersion in ultra-low, less than 0.05 wt%, Ag enriched polymeric based nanocomposite manufactured with an innovative nano-coating fragmentation technique. The phasegrams obtained with the presented technique clearly showed clusters or bundles of Ag nanoparticles when present, down to the size of 6 µm. Therefore, the new NDE approach can be applied to verify that the expected levels of dispersion are met in the production process

Detection of thyrotropin binding inhibitory activity in neonatal blood spots

Recent studies have suggested that maternal TSH receptor-blocking antibodies might be of primary etiological importance in some cases of transient congenital hypothyroidism (CH). Because these antibodies are extremely potent, we evaluated the feasibility of identifying babies at risk by using readily available newborn blood spots. Blood spots obtained from 84 normal babies (group 1) and from 354 infants whose initial T4 was less than the tenth percentile for the assay and whose TSH was 40 mU/L or more (group 2) were studied without knowledge of the diagnosis. Blood was eluted from spots overnight and evaluated for [125I]TSH binding inhibition (TBI) to solubilized porcine thyroid membranes. Four spots obtained from 3 group 2 babies, but none of those from the group 1 infants, exhibited TBI activity greater than 3 SD above the normal mean (33.9%). Four additional hypothyroxinemic infants whose mothers had Graves\u27 disease were also negative. Subsequent follow-up revealed that all 3 positive babies had transient CH, and all 3 mothers had primary myxedema. Potent TBI activity was confirmed in the serum of all 3 mothers and in the 2 babies in whom it was evaluated at birth. We conclude that newborn blood spots can be used to detect potent maternal TBI activity, and that this identifies a baby likely to have transient, rather than permanent, CH. Because of their stability and ease of collection and handling, newborn blood spots should offer a convenient tool for future studies aimed at defining in more detail the incidence and clinical characteristics of this unique syndrome

Incidence of transient congenital hypothyroidism due to maternal thyrotropin receptor-blocking antibodies in over one million babies

To determine the incidence of transient congenital hypothyroidism due to TSH receptor-blocking antibodies, we screened dried blood specimens obtained from 788 neonates identified as having possible congenital hypothyroidism (from a total population of 1,614,166 babies) and 121 controls. A RRA was used. The potency of blood spot TSH binding inhibitory activity was compared with the severity of congenital hypothyroidism to assess the possible etiological relationship. Maternal serum was studied to confirm the presence of blocking antibodies by both RRA and bioassay. Blood spots obtained from 9 infants contained potent TSH receptor-blocking activity. Samples from 2 additional babies, studied because of clinical suspicion of the disease, were also positive. Long term outcome was known in 8 of the 11 babies, and all had transient disease. Neonates with TSH receptor-blocking activity greater than 132 U/L had a significantly lower T4 level (P \u3c 0.05) and higher TSH (P \u3c 0.005) than those in whom TSH binding-inhibitory activity was less than 132 U/L. All 9 mothers had autoimmune thyroid disease, and 3 had more than 1 affected child. Potent blocking activity was present in 7 maternal serum samples as long as 7 yr after the births of their affected babies. We conclude that measurement of TSH binding-inhibitory activity in dried neonatal blood specimens is a simple and effective method to predict the occurrence of transient congenital hypothyroidism. The incidence of this disorder in North America is 1 in 180,000 normal infants, or approximately 2% of babies with congenital hypothyroidism

Trehalose administration in C57BL/6N old mice affects healthspan improving motor learning and brain anti-oxidant defences in a sex-dependent fashion: a pilot study

Aim of this study was to characterize the effects of oral trehalose administration (2%w/v) on healthspan in old mice. Trehalose was administered in drinking water for 1 month to male and female C57BL/6N mice aged 25-months. After behavioral phenotyping (grip strength, beam walking and rotarod tests), autophagy (LC3-II/actin) and oxidative stress were tested in the cerebral cortex and gastrocnemius muscle. The latter parameter was indirectly assessed by evaluating carbonyl groups added to proteins as a result of oxidative reactions, in addition to central levels of NRF2 protein, a transcription factor that regulates the expression of antioxidant enzymes. In comparison with sex-matched controls, trehalose-treated males performed better in motor planning and coordination tasks. This behavioral phenotype was associated with an activation of the ubiquitin-proteasome system, autophagy and antioxidant defences in cerebral cortex. Independently from trehalose administration, females were characterized by better motor performance and showed higher levels of ubiquitinated proteins and NRF2 in cerebral cortex, suggesting an up-regulation of basal antioxidant defences. In conclusion, trehalose was effective in counteracting some aspects of age-related decay, with specific effects in male and female subjects

Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex

We measured seasonal patterns of net ecosystem exchange (NEE) of CO2 in a diverse peatland complex underlain by discontinuous permafrost in northern Manitoba, Canada, as part of the Boreal Ecosystems Atmosphere Study (BOREAS). Study sites spanned the full range of peatland trophic and moisture gradients found in boreal environments from bog (pH 3.9) to rich fen (pH 7.2). During midseason (July‐August, 1996), highest rates of NEE and respiration followed the trophic sequence of bog (5.4 to −3.9 μmol CO2 m−2 s−1) \u3c poor fen (6.3 to −6.5 μmol CO2 m−2 s−1) \u3c intermediate fen (10.5 to −7.8 μmol CO2 m−2 s−1) \u3c rich fen (14.9 to −8.7 μmol CO2m−2 s−1). The sequence changed during spring (May‐June) and fall (September‐October) when ericaceous shrub (e.g., Chamaedaphne calyculata) bogs and sedge (Carex spp.) communities in poor to intermediate fens had higher maximum CO2 fixation rates than deciduous shrub‐dominated (Salix spp. and Betula spp.) rich fens. Timing of snowmelt and differential rates of peat surface thaw in microtopographic hummocks and hollows controlled the onset of carbon uptake in spring. Maximum photosynthesis and respiration were closely correlated throughout the growing season with a ratio of approximately 1/3 ecosystem respiration to maximum carbon uptake at all sites across the trophic gradient. Soil temperatures above the water table and timing of surface thaw and freeze‐up in the spring and fall were more important to net CO2 exchange than deep soil warming. This close coupling of maximum CO2 uptake and respiration to easily measurable variables, such as trophic status, peat temperature, and water table, will improve models of wetland carbon exchange. Although trophic status, aboveground net primary productivity, and surface temperatures were more important than water level in predicting respiration on a daily basis, the mean position of the water table was a good predictor (r2 = 0.63) of mean respiration rates across the range of plant community and moisture gradients. Q10 values ranged from 3.0 to 4.1 from bog to rich fen, but when normalized by above ground vascular plant biomass, the Q10 for all sites was 3.3

Biomechanical properties and histomorphometric features of aortic tissue in patients with or without bicuspid aortic valve

Background: We sought to investigate and compare biomechanical properties and histomorphometric findings of thoracic ascending aorta aneurysm (TAA) tissue from patients with bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) in order to clarify mechanisms underlying differences in the clinical course. Methods: Circumferential sections of TAA tissue in patients with BAV (BAV-TAA) and TAV (TAV-TAA) were obtained during surgery and used for biomechanical tests and histomorphometrical analysis. Results: In BAV-TAA, we observed biomechanical higher peak stress and lower Young modulus values compared with TAV-TAA wall. The right lateral longitudinal region seemed to be the most fragile zone of the TAA wall. Mechanical stress-induced rupture of BAV-TAA tissue was sudden and uniform in all aortic wall layers, whereas a gradual and progressive aortic wall breakage was described in TAV-TAA. Histomorphometric analysis revealed higher amount of collagen but not elastin in BAV-TAA tunica media. Conclusions: The higher deformability of BAV-TAA tissue supports the hypothesis that increased wall shear stress doesn't explain the increased risk of sudden onset of rupture and dissection; other mechanisms, likely related to alteration of specific genetic pathways and epigenetic signals, could be investigated to explain differences in aortic dissection and rupture in BAV patients

Relationship between ecosystem productivity and photosynthetically-active radiation for northern peatlands

We analyzed the relationship between net ecosystem exchange of carbon dioxide (NEE) and irradiance (as photosynthetic photon flux density or PPFD), using published and unpublished data that have been collected during midgrowing season for carbon balance studies at seven peatlands in North America and Europe. NEE measurements included both eddy-correlation tower and clear, static chamber methods, which gave very similar results. Data were analyzed by site, as aggregated data sets by peatland type (bog, poor fen, rich fen, and all fens) and as a single aggregated data set for all peatlands. In all cases, a fit with a rectangular hyperbola (NEE = α PPFD Pmax/(α PPFD + Pmax) + R) better described the NEE-PPFD relationship than did a linear fit (NEE = β PPFD + R). Poor and rich fens generally had similar NEE-PPFD relationships, while bogs had lower respiration rates (R = −2.0μmol m−2s−1 for bogs and −2.7 μmol m−2s−1 for fens) and lower NEE at moderate and high light levels (Pmax = 5.2 μmol m−2s−1 for bogs and 10.8 μmol m−2s−1 for fens). As a single class, northern peatlands had much smaller ecosystem respiration (R = −2.4 μmol m−2s−1) and NEE rates (α = 0.020 and Pmax = 9.2μmol m−2s−1) than the upland ecosystems (closed canopy forest, grassland, and cropland) summarized by Ruimy et al. [1995]. Despite this low productivity, northern peatland soil carbon pools are generally 5–50 times larger than upland ecosystems because of slow rates of decomposition caused by litter quality and anaerobic, cold soils