On some factors influencing dissolved silicon distribution over the northwest African shelf

Nitrate concentrations in the upwelling source waters observed near Cabo Corbeiro during the JOINT-I experiment were more than twice as high as dissolved silicon concentrations, but dissolved silicon concentrations in the surface layers fell below 0.5 µg-atoms..

Denitrification rates in the eastern tropical South Pacific

Measurements of microbial metabolism suggest that the denitrification rate in the oxygen deficient waters of the eastern tropical South Pacific was approximately 2.5 × 1013g N yr-1 during September 1976-May 1977. This rate may be considerably higher than the rate that existed before ~ 1972...

Biological observations in the marginal ice zone of the East Greenland Sea

The distribution of nutrients, phytoplankton and zooplankton was investigated during summer, 1983 in the marginal ice zone of the East Greenland Sea. Nutrient levels, especially inorganic nitrogen, were extremely low, and probably limited the growth of phytoplankton during this period. An ammonium maximum at the base of the euphotic zone, generally around 50 m, was found repeatedly and appeared to be controlled by active nitrogen regeneration and decreased ammonium uptake at low light levels. Chlorophyll a levels were elevated at the ice-edge, but were even higher in an area influenced by an eddy. Species of zooplankton were accurate indicators of the origin of the two major water masses in this area, and zooplanktonic biomass was similar to other polar regions. Calculations of their impact on phytoplankton distributions indicated that grazing losses resulting from ingestion by large copepads may have been small. The dynamics associated with mesoscale eddies appear to be important in introducing new nitrogen into the euphotic zone and structuring the distribution of plant biomass at the ice-edge of the East Greenland Sea

A subsurface particle maximum layer and enhanced microbial activity in the secondary nitrite maximum of the northeastern tropical Pacific Ocean

Profiles of light transmission, dissolved oxygen, dissolved nutrients, electron transport system (ETS) activity, temperature and salinity were made in the northeastern tropical Pacific Ocean. A particle maximum at 150–300 m within the oxygen minimum and secondary nitrite maximum was associated with the salinity maximum of Subtropical Subsurface Water. A subsurface maximum in ETS activity was also found to be associated with the secondary nitrite maximum and the particle maximum. Persistence of these features at a constant depth and their location within a minimum in vertical static stability suggest an advective and/or in situ origin for the particles and an in situ development of the associated chemical and biochemical extremes

To Binge or not To Binge: viewers’ moods and behaviors during the consumption of subscribed video streaming

The popularity of internet-distributed TV entertainment services, such as Netflix, has transformed TV consumption behavior. Currently, the level of control viewers have over their TV experiences, along with the release of com plete seasons at once, are some of the factors that stimulate the so-called binge watching phenomenon (the consumption of several episodes of a program in a single sitting). Most of binge-watching studies have focused on viewers’ habits and health effects. This paper presents a study that relates to viewers’ behaviors and moods. It was carried out with 13 young participants at their home, watching online content, collecting physiological, inertial, and self-reported data. We iden tify and compare binge-watching with non-binge-watching behaviors. Our results suggest that while viewers recur to online serial entertainment in pursuit of lei sure related needs, such as relaxation, relief from boredom and escapism, the act of binge-watching tends to make them feel rather unsatisfied with no change in Arousal. Nevertheless, in binge-watching the Positive Affect increases while the Negative decreases. Moreover, watching a single episode only, tends to result in increased arousal and but not necessarily in increased satisfaction. This prelimi nary finding can be the starting point of fruitful future investigations on unpack ing further motives and nuances from this outcome.info:eu-repo/semantics/publishedVersio

Denitrification rates and excess nitrogen gas concentrations in the Arabian Sea oxygen deficient zone

Rates of canonical, i.e. heterotrophic, water-column denitrification were measured by 15N incubation techniques at a number of coastal and open ocean stations in the Arabian Sea. Measurements of N2:Ar gas ratios were also made to obtain independent estimates of N2 excess resulting from denitrification. Measured denitrification rates (15NO3-→15-14N2) at open ocean stations averaged 9.1±1.0 nmol N l-1 d-1 (n=15), and coastal rates averaged 33.2±12.4 nmol N l-1 d-1 (n=18). When extrapolated to the entire Arabian Sea, deep measurements within the offshore perennial suboxic zone indicate an overall denitrification rate of 41 Tg N a-1±18 Tg N a-1, which is within the range (10-44 Tg N a-1) of previous estimates for canonical denitrification in the region based on stoichiometric calculations and electron transport system activity. Nitrogen excess gas measurements predict a larger nitrogen anomaly than estimated by classical stoichiometric methods (maximum anomaly=23 μg at N l-1 vs. 13 μg at N l-1, respectively). This mismatch may result from incorrect assumptions of Redfield stoichiometry inherent in the nitrate deficit calculation, inputs of new nitrogen through N-fixation, N2 contributions from sedimentary denitrification along continental margins, the anammox reaction, and metal catalyzed denitrification reactions. Nevertheless, if denitrification is defined as the conversion of combined nitrogen to a gaseous end product, then the data suggest that denitrification in the Arabian Sea may have been underestimated so far

Novel transglutaminase 1 mutations in patients affected by lamellar ichthyosis

Lamellar Ichthyosis (LI) is a form of congenital ichthyosis that is caused by mutations in the TGM1 gene that encodes for the transglutaminase 1 (TG1) enzyme. Functional inactivation of TG1 could be due to mutations, deletion or insertions. In this study, we have screened 16 patients affected by LI and found six new mutations: two transition/transversion (R37G, V112A), two nonsense mutations and two putative splice site both leading to a premature stop codon. The mutations are localized in exons 2 (N-terminal domain), 5, 11 (central catalytic domain), and none is located in the two beta-barrel C-terminal domains. In conclusion, this study expands the current knowledge on TGM1 mutation spectrum, increasing the characterization of mutations would provide more accurate prenatal genetic counselling for parents at-risk individuals

PLA-based mineral-doped scaffolds seeded with human periapical cyst-derived MSCs: A promising tool for regenerative healing in dentistry

Human periapical cyst mesenchymal stem cells (hPCy-MSCs) are a newly discovered cell population innovatively collected from inflammatory periapical cysts. The use of this biological waste guarantees a source of stem cells without any impact on the surrounding healthy tissues, presenting a valuable potential in tissue engineering and regenerative medicine applications. In the present study, hPCy-MSCs were collected, isolated, and seeded on three experimental mineral-doped porous scaffolds produced by the thermally-induced phase-separation (TIPS) technique. Mineral-doped scaffolds, composed of polylactic acid (PLA), dicalcium phosphate dihydrate (DCPD), and/or hydraulic calcium silicate (CaSi), were produced by TIPS (PLA-10CaSi, PLA-5CaSi-5DCPD, PLA-10CaSi-10DCPD). Micro-CT analysis evaluated scaffolds micromorphology. Collected hPCy-MSCs, characterized by cytofluorimetry, were seeded on the scaffolds and tested for cell proliferation, cells viability, and gene expression for osteogenic and odontogenic differentiation (DMP-1, OSC, RUNX-2, HPRT). Micro-CT revealed an interconnected highly porous structure for all the scaffolds, similar total porosity with 99% open pores. Pore wall thickness increased with the percentage of CaSi and DCPD. Cells seeded on mineral-doped scaffolds showed a superior proliferation compared to pure PLA scaffolds (control), particularly on PLA-10CaSi-10DCPD at day 12. A higher number of non-viable (red stained) cells was observable on PLA scaffolds at days 14 and 21. DMP-1 expression increased in hPCy-MSCs cultured on all mineral-doped scaffolds, in particular on PLA-5CaSi-5DCPD and PLA-10CaSi-10DCPD. In conclusion, the innovative combination of experimental scaffolds colonized with autologous stem cells from periapical cyst represent a promising strategy for regenerative healing of periapical and alveolar bone

The emerging role of NG2 in pediatric diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine gliomas (DIPGs) have a dismal prognosis and are poorly understood brain cancers. Receptor tyrosine kinases stabilized by neuron-glial antigen 2 (NG2) protein are known to induce gliomagenesis. Here, we investigated NG2 expression in a cohort of DIPG specimens (n= 50). We demonstrate NG2 expression in the majority of DIPG specimens tested and determine that tumors harboring histone 3.3 mutation express the highest NG2 levels. We further demonstrate that microRNA 129-2 (miR129-2) is downregulated and hypermethylated in human DIPGs, resulting in the increased expression of NG2. Treatment with 5-Azacytidine, a methyltransferase inhibitor, results in NG2 downregulation in DIPG primary tumor cells in vitro. NG2 expression is altered (symmetric segregation) in mitotic human DIPG and mouse tumor cells. These mitotic cells co-express oligodendrocyte (Olig2) and astrocyte (glial fibrillary acidic protein, GFAP) markers, indicating lack of terminal differentiation. NG2 knockdown retards cellular migration in vitro, while NG2 expressing neurospheres are highly tumorigenic in vivo, resulting in rapid growth of pontine tumors. NG2 expression is targetable in vivo using miR129-2 indicating a potential avenue for therapeutic interventions. This data implicates NG2 as a molecule of interest in DIPGs especially those with H3.3 mutation

Global rates of water-column denitrification derived from nitrogen gas measurements

Biologically available nitrogen (N) limits phytoplankton growth over much of the ocean. The rate at which N is removed from the contemporary ocean by denitrifying bacteria is highly uncertain 1-3. Some studies suggest that N losses exceed inputs 2,4-6; others argue for a balanced budget 3,7,8. Here, we use a global ocean circulation model to simulate the distribution of N 2 gas produced by denitrifying bacteria in the three main suboxic zones in the open ocean. By fitting the model to measured N 2 gas concentrations, we infer a globally integrated rate of water-column denitrification of 66 ±6 Tg N yr -1. Taking into account isotopic constraints on the fraction of denitrification occurring in the water column versus marine sediments, we estimate that the global rate of N loss from marine sediments and the oceanic water column combined amounts to around 230 ±60 Tg N yr -1. Given present estimates of N input rates, our findings imply a net loss of around 20 ± 70 Tg of N from the global ocean each year, indistinguishable from a balanced budget. A balanced N budget, in turn, implies that the marine N cycle is governed by strong regulatory feedbacks. © 2012 Macmillan Publishers Limited. All rights reserved