The species concept in marine phytoplankton is defined based on genomic, morphological, and functional properties. Reports of intraspecific diversity are widespread across major phytoplankton groups ...but the impacts of this variation on ecological and biogeochemical processes are often overlooked. Intraspecific diversity is well known within coccolithophores, which play an important role in the marine carbon cycle via production of particulate inorganic carbon. In this study, we investigated strain-specific responses to temperature in terms of morphology, carbon production, and carbonate mineralogy using a combination of microscopy, elemental analysis, flow cytometry, and nuclear magnetic resonance. Two strains of the cosmopolitan coccolithophore E. huxleyi isolated from different regions (subtropical, CCMP371; temperate, CCMP3266) were cultured under a range of temperature conditions (10°C, 15°C, and 20°C) using batch cultures and sampled during both exponential and stationary growth. Results for both strains showed that growth rates decreased at lower temperatures while coccosphere size increased. Between 15°C and 20°C, both strains produced similar amounts of total carbon, but differed in allocation of that carbon between particulate inorganic carbon (PIC) and particulate organic carbon (POC), though temperature effects were not detected. Between 10°C and 20°C, temperature effects on daily production of PIC and POC, as well as the cellular quota of POC were detected in CCMP3266. Strain-specific differences in coccolith shedding rates were found during exponential growth. In addition, daily shedding rates were negatively related to temperature in CCMP371 but not in CCMP3266. Despite differences in rates of particulate inorganic carbon production, both strains were found to produce coccoliths composed entirely of pure calcite, as established by solid-state 13C and 43Ca NMR and X-ray diffraction measurements. These results highlight the limitations of the species concept and the need for a trait-based system to better quantify diversity within marine phytoplankton communities.
The VHE SED modelling of Markarian 501 in 2009 Sahu, S; López Fortín, C E; Iglesias Martínez, M E ...
Monthly notices of the Royal Astronomical Society,
02/2020, Letnik:
492, Številka:
2
Journal Article
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ABSTRACT
The high energy blazar, Markarian 501 was observed as a part of multi-instrument and multiwavelength campaign spanning the whole electromagnetic spectrum for 4.5 months during March 15 to ...August 1, 2009. On May 1, Whipple 10 m telescope observed a very strong γ-ray flare in a time interval of about 0.5 h. Apart from this flare, high state and low state emissions were also observed by Whipple, VERITAS and MAGIC telescopes. Using the photohadronic model and accounting for the absorption of the extragalactic background light to these very high energy γ-rays, excellent fits are obtained for the observed spectra. We have shown that the intrinsic spectrum for low state emission is flat, however, for high and very high states this is a power-law with slowly increasing exponent.
We present a study in which the suitability of potassium promoted iron-based Fischer–Tropsch (FT) catalysts for the generation of synthetic natural gas additives via the hydrogenation of carbon ...dioxide through a combined reverse water gas shift (WGS) and FT reaction is studied. Using novel in situ instrumentation based on XRD and magnetometry techniques the reversible conversion of metallic iron to Hägg carbide under reaction conditions and its decomposition in hydrogen could be monitored. The facilitating effect of potassium in the formation of iron carbide could be exposed as function of time on stream. While the FT reaction was reduced in the presence of high potassium loadings the reverse WGS reaction seemed to be unperturbed. A faster activation of an iron phase obtained via the decomposition of iron carbide, compared to the initial activation of a pristine iron phase obtained via the reduction of iron oxide was witnessed.
Graphical Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disease characterized by an overexpression and mislocalization of epidermal growth factor receptor (EGFR) to the apical membranes of ...cystic epithelial cells. Nimotuzumab is a humanized antibody that recognizes an extracellular domain III of human EGFR. The aim of this study was to assess the pharmacokinetic behavior of nimotuzumab in patients with ADPKD given as a single dose. A phase I, single‐center, and noncontrolled open clinical study was conducted. Five patients were enrolled at each of the following fixed‐dose levels: 50, 100, 200, and 400 mg. Intravenous continuous infusions of nimotuzumab were administered every 14 days during a year, except the first administration, when blood samples were drawn during 28 days for pharmacokinetic assessments. Subjects were closely monitored during the trial and at completion of the administration of nimotuzumab, including the anti‐idiotypic response. For the first time, nimotuzumab was used for treating a nononcological disease. The administration of nimotuzumab showed dose‐dependent kinetics. Nimotuzumab does not develop anti‐idiotypic response against the murine portion present in the hypervariable region of the antibody present in the serum of the patients treated. No significant differences were found in the systemic clearance between the 100‐ and 400‐mg dose, which indicates that the optimal biological dose is in this range of dose.
The treatment of symptomatic carotid near-occlusion is controversial. Our aim was to analyze the results of carotid endarterectomy and carotid artery stent placement in patients with symptomatic ...carotid near-occlusion and to identify factors related to technical failure, periprocedural complications, and restenosis.
We conducted a multicenter, prospective nonrandomized study. Patients with angiography-confirmed carotid near-occlusion were included. We assessed the revascularization rate and periprocedural stroke or death. Twenty-four-month clinical and carotid imaging follow-up was performed, and rates of carotid restenosis or occlusion, ipsilateral stroke, and mortality were analyzed. Carotid artery stent placement, carotid endarterectomy, and medical treatment were compared.
One hundred forty-one patients were included. Forty-four carotid artery stent placement and 23 carotid endarterectomy procedures were performed within 6 months after the event. Complete revascularization was achieved in 83.6%, 81.8% in the carotid artery stent placement group and 87% with carotid endarterectomy (
= .360). Periprocedural stroke or death occurred in 6% (carotid artery stent placement = 2.3%; carotid endarterectomy = 13%;
= .077) and was not related to revascularization failure. The carotid restenosis or occlusion rate was 8.3% (5% restenosis, 3.3% occlusion); with carotid artery stent placement it was 10.5%; and with carotid endarterectomy it was 4.5% (
= .419). The 24-month cumulative rate of ipsilateral stroke was 4.8% in the carotid artery stent placement group, 17.4% for carotid endarterectomy, and 13.1% for medical treatment (
= .223). Mortality was 12%, 4.5%, and 5.6%, respectively (
= .422). Revascularization failure and restenosis occurred more frequently in patients with full collapse compared with patients without full collapse (33.3% versus 5.6%,
= .009; 21.4% versus 2.9%,
= .032, respectively).
Carotid artery stent placement and carotid endarterectomy are associated with high rates of failure and periprocedural stroke. Carotid near-occlusion with full collapse appears to be associated with an increased risk of technical failure and restenosis. Carotid near-occlusion revascularization does not seem to reduce the risk of stroke at follow-up compared with medical treatment.
Abstract The calcaneus is a desirable site for harvesting autologous bone for use in foot surgery. However, fracture of the calcaneus is a serious complication associated with bone harvesting from ...this site. Currently it is unknown how much bone may be safely harvested from the calcaneus without inducing a fracture. The purpose of this study was to investigate the effect of progressive bone removal from the calcaneus onto the mechanical stress redistribution of the foot, and therefore on the increase in fracture risk. Different loads were applied on the talus to evaluate the calcaneus stress distribution at different situations. Because of the potential increase in mechanical stress in the calcaneus, secondary to contraction of the Achilles tendon, we also evaluated the mechanical behavior properties of the foot with increasing traction force in the Achilles tendon. A three-dimensional (3D) finite element (FE) model developed from CT images obtained from a healthy individual was used to compute displacement, tension and compression stresses in six situations, including intact foot, and five depth of the bone block removed, with a maximum depth of 7.5 mm. The results from these simulations indicated that when the maximum load was applied at the Achilles tendon, the tension stress increased from 42.16 MPa in the intact foot to 86.28 MPa with maximum bone harvesting. Furthermore, as the volume of bone extracted from the calcaneus increases, there is a redistribution of stresses that differs significantly from the intact foot. In fact, although the maximum stress was not significantly affected by increasing the volume of bone harvested—except when increasing the Achilles tendon force-, stresses did increase in areas of the calcaneus is vulnerable to injury, leading to an increase in fracture risk.
Hydropower is a well-known technology, applied worldwide for electricity generation from renewable sources. Within the current framework, some studies have started to consider its application to ...existing urban water systems, to harness an excess of energy that otherwise would be wasted. This research sought to determine a methodology to assess the potential of hydropower application to wastewater treatment plants (WWTPs), regarding different aspects of sustainability. Firstly, previously developed methodologies for potential assessment in this sector at a country level were analyzed. Secondly, data from existing real case studies were gathered from publicly available documents and a theoretical analysis of their actual performance was conducted to validate assumptions made in the previous methodologies. As a result, the proposed new approach suggests adapting methodologies for potential assessment at a lower level, considering possible driving factors, other than economic feasibility. To define the study area, the management model scope should be considered. The power to determine the cut-off point for a WWTP to be considered as a potential site, is proposed to be lowered according to technical feasibility. Additionally, bearing in mind the sustainability concept, social or environmental factors should also be introduced in the methodology, tailored to the region being assessed. This novel perspective could provide a closer approach to the most likely decision-making level for these kinds of strategies in the wastewater industry.
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