Intentional Islanding of Active Distribution Networks by GenSets: An Analysis of Technical Constraints and Opportunities

The willingness to improve the security and reliability of power supply to end-users, often pushed by prescriptions of national regulatory authorities, is bringing considerable challenges for distribution system operators. Islanding a portion of the public distribution network after a fault is considered a measure to mitigate the effects of service interruptions. This procedure is usually carried out by counterfeeding the grid through a generator set (GenSet). Even if this approach is widely adopted around the world, reenergizing the grid and keeping the electric island stable is not a trivial task. In this framework, the scope of this paper is to provide a set of technical guidelines for the usage of GenSets to supply public grids in emergency conditions. The goal is to highlight the static and dynamic limits of the GenSet operations and simplify their exploitation for the grid operators. The numerical analyses, which have been carried out through the RMS simulation tool of the DigSilent PowerFactory software, also aim to evaluate the technical constraints in the case of active networks, which involve distributed generation implementing regulations according to ENTSO-E and Italian technical standards

Relationship between lactation curve function and phenotypic variance in random regression Test Day models

In Random Regression models (RRM), the most updated version of Test Day (TD) models, the lactation curve is split into a fixed average curve and a random animal specific part (deviation from the average curve) (Schaeffer, 2004). The variance component of the RR coefficients determines the (co) variance function of each pair of days in milk (DIM) (Pool and Meuwissen, 2000). Very different patterns of variance functions have been reported in literature, and several authors pointed out a possible rule of the type of function chosen as RR sub-model and data structure (Kettunen et al., 2000; Meyer, 1998). Aim of this work is to investigate some possible reasons for such results, in particular the effects of the mathematical function and of the possible occurrence of different shapes of lactation curve (regular and atypical)

Chronic \u3b1-synuclein accumulation in rat hippocampus induces lewy bodies formation and specific cognitive impairments

Occurrence of Lewy bodies (LBs)/Lewy neurites (LNs) containing misfolded fibrillar a-synuclein (a-syn) is one of the pathologic hallmarks of memory impairment-linked synucleinopathies, such as Parkinson\u2019s disease (PD) and dementia with LBs (DLB). While it has been shown that brainstem LBs may contribute to motor symptoms, the neuropatho-logical substrates for cognitive symptoms are still elusive. Here, recombinant mouse a-syn fibrils were bilaterally injected in the hippocampus of female Sprague Dawley rats, which underwent behavioral testing for sensorimotor and spatial learning and memory abilities. No sensorimotor deficits affecting Morris water maze task performance were observed, nor was any reference memory disturbances detectable in injected animals. By contrast, significant impairments in working memory performance became evident at 12 months postinjection. These deficits were associated to a time-dependent increase in the levels of phosphorylated a-syn at Ser129 and in the stereologically esti-mated numbers of proteinase K (PK)-resistant a-syn aggregates within the hippocampus. Interestingly, pathologic a-syn aggregates were found in the entorhinal cortex and, by 12 months postinjection, also in the vertical limb of the diagonal band and the piriform cortices. No pathologic a-syn deposits were found within the substantia nigra (SN), the ventral tegmental area (VTA), or the striatum, nor was any loss of dopaminergic, noradrenergic, or cholinergic neurons detected in a-syn-injected animals, compared with controls. This would suggest that the behavioral impairmentsseeninthea-syn-injected animals might be determined by the long-term a-syn neuropathology, rather than by neurodegeneration per se, thus leading to the onset of working memory deficits

Stable Propagation of a Burst Through a One-Dimensional Homogeneous Excitatory Chain Model of Songbird Nucleus HVC

We demonstrate numerically that a brief burst consisting of two to six spikes can propagate in a stable manner through a one-dimensional homogeneous feedforward chain of non-bursting neurons with excitatory synaptic connections. Our results are obtained for two kinds of neuronal models, leaky integrate-and-fire (LIF) neurons and Hodgkin-Huxley (HH) neurons with five conductances. Over a range of parameters such as the maximum synaptic conductance, both kinds of chains are found to have multiple attractors of propagating bursts, with each attractor being distinguished by the number of spikes and total duration of the propagating burst. These results make plausible the hypothesis that sparse precisely-timed sequential bursts observed in projection neurons of nucleus HVC of a singing zebra finch are intrinsic and causally related.Comment: 13 pages, 6 figure

MHz Unidirectional Rotation of Molecular Rotary Motors

A combination of cryogenic UV-vis and CD spectroscopy and transient absorption spectroscopy at ambient temperature is used to study a new class of unidirectional rotary molecular motors. Stabilization of unstable intermediates is achieved below 95 K in propane solution for the structure with the fastest rotation rate, and below this temperature measurements on the rate limiting step in the rotation cycle can be performed to obtain activation parameters. The results are compared to measurements at ambient temperature using transient absorption spectroscopy, which show that behavior of these motors is similar over the full temperature range investigated, thereby allowing a maximum rotation rate of 3 MHz at room temperature under suitable irradiation conditions

Multiple myeloma-derived exosomes are enriched of amphiregulin (AREG) and activate the epidermal growth factor pathway in the bone microenvironment leading to osteoclastogenesis

Background: Multiple myeloma (MM) is a clonal plasma cell malignancy associated with osteolytic bone disease. Recently, the role of MM-derived exosomes in the osteoclastogenesis has been demonstrated although the underlying mechanism is still unknown. Since exosomes-derived epidermal growth factor receptor ligands (EGFR) are involved in tumor-associated osteolysis, we hypothesize that the EGFR ligand amphiregulin (AREG) can be delivered by MM-derived exosomes and participate in MM-induced osteoclastogenesis. Methods: Exosomes were isolated from the conditioned medium of MM1.S cell line and from bone marrow (BM) plasma samples of MM patients. The murine cell line RAW264.7 and primary human CD14 + cells were used as osteoclast (OC) sources. Results: We found that AREG was specifically enriched in exosomes from MM samples and that exosomes-derived AREG led to the activation of EGFR in pre-OC, as showed by the increase of mRNA expression of its downstream SNAIL in both RAW264.7 and CD14 + cells. The presence of neutralizing anti-AREG monoclonal antibody (mAb) reverted this effect. Consequently, we showed that the effect of MM-derived exosomes on osteoclast differentiation was inhibited by the pre-treatment of exosomes with anti-AREG mAb. In addition, we demonstrated the ability of MM-derived AREG-enriched exosomes to be internalized into human mesenchymal stromal cells (MSCs) blocking osteoblast (OB) differentiation, increasing MM cell adhesion and the release of the pro-osteoclastogenic cytokine interleukin-8 (IL8). Accordingly, anti-AREG mAb inhibited the release of IL8 by MSCs suggesting that both direct and indirect effects are responsible for AREG-enriched exosomes involvement on MM-induced osteoclastogenesis. Conclusions: In conclusion, our data indicate that AREG is packed into MM-derived exosomes and implicated in OC differentiation through an indirect mechanism mediated by OBs