Impacts of renewable energy resources on effectiveness of grid‐integrated systems: succinct review of current challenges and potential solution strategies

This study is aimed at a succinct review of practical impacts of grid integration of renewable energy systems on effectiveness of power networks, as well as often employed state‐of-the‐art solution strategies. The renewable energy resources focused on include solar energy, wind energy, biomass energy and geothermal energy, as well as renewable hydrogen/fuel cells, which, although not classified purely as renewable resources, are a famous energy carrier vital for future energy sustainability. Although several world energy outlooks have suggested that the renewable resources available worldwide are sufficient to satisfy global energy needs in multiples of thousands, the different challenges often associated with practical exploitation have made this assertion an illusion to date. Thus, more research efforts are required to synthesize the nature of these challenges as well as viable solution strategies, hence, the need for this review study. First, brief overviews are provided for each of the studied renewable energy sources. Next, challenges and solution strategies associated with each of them at generation phase are discussed, with reference to power grid integration. Thereafter, challenges and common solution strategies at the grid/electrical interface are discussed for each of the renewable resources. Finally, expert opinions are provided, comprising a number of aphorisms deducible from the review study, which reveal knowledge gaps in the field and potential roadmap for future research. In particular, these opinions include the essential roles that renewable hydrogen will play in future energy systems; the need for multi‐sectoral coupling, specifically by promoting electric vehicle usage and integration with renewable‐based power grids; the need for cheaper energy storage devices, attainable possibly by using abandoned electric vehicle batteries for electrical storage, and by further development of advanced thermal energy storage systems (overviews of state‐of‐the‐art thermal and electrochemical energy storage are also provided); amongst others

Performance Assessment of Low-Temperature A-CAES (Adiabatic Compressed Air Energy Storage) Plants

The widespread diffusion of renewable energy sources calls for the development of high-capacity energy storage systems as the A-CAES (Adiabatic Compressed Air Energy Storage) systems. In this framework, low temperature (100°C–200°C) A-CAES (LT-ACAES) systems can assume a key role, avoiding some critical issues connected to the operation of high temperature ones. In this paper, two different LT-ACAES configurations are proposed. The two configurations are characterized by the same turbomachines and compressed air storage section, while differ in the TES section and its integration with the turbomachinery. In particular, the first configuration includes two separated cycles: the working fluid (air) cycle and the heat transfer fluid (HTF) cycle. Several heat exchangers connect the two cycles allowing to recover thermal energy from the compressors and to heat the compressed air at the turbine inlet. Two different HTFs were considered: air (case A) and thermal oil (case B). The second configuration is composed of only one cycle, where the operating fluid and the HTF are the same (air) and the TES section is composed of three different packed-bed thermal storage tanks (case C). The tanks directly recover the heat from the compressors and heat the air at each turbine inlet, avoiding the use of heat exchangers. The LT-ACAES systems were modelled and simulated using the ASPEN-Plus and the MATLAB-Simulink environments. The main aim of this study was the detailed analysis of the reciprocal influence between the turbomachinery and the TES system; furthermore, the performance evaluation of each plant was carried out assuming both on-design and off-design operating conditions. Finally, the different configurations were compared through the main performance parameters, such as the round-trip efficiency. A total power output of around 10 MW was set, leading to a TES tank volume ranging between 500 and 700 m3. The second configuration with three TES systems appears to be the most promising in terms of round-trip efficiency since the energy produced during the discharging phase is greater. In particular, the round-trip efficiency of the LT-ACAES ranges between 0.566 (case A) to 0.674 (case C). Although the second configuration assures the highest performance, the effect of operating at very high pressures inside the tanks should be carefully evaluated in terms of overall costs

Pulmonary transit time as a marker of diastolic dysfunction in Takotsubo syndrome

AIM: To evaluate the pulmonary transit time (PTT) and its derived parameters using cardiac magnetic resonance imaging (CMRI) as markers of diastolic dysfunction in Takotsubo syndrome (TS) and its relationship with transthoracic echocardiography and CMRI parameters. MATERIALS AND METHODS: Twenty-two patients with TS, who exhibited diastolic dysfunction as assessed by transthoracic echocardiography, were enrolled retrospectively and the PTT, pulmonary transit time index (PTTI), and pulmonary blood volume index (PBVI) were evaluated using first-pass CMRI. PTT was calculated as the number of cardiac cycles required for a bolus of contrast agent to move from the right ventricle (RV) to the left ventricle (LV), whereas PTTI represents the PTT interval corrected for the heart rate. Finally, PBVI was calculated as the product of PTTI, and RV stroke volume indexed for body surface area. Normal references of PTT, PTTI, and PBVI were evaluated in a cohort of 20 age- and sex-matched healthy controls. RESULTS: Compared with healthy subjects, TS patients showed significantly higher PTT, PTTI, and PBVI (p=0.0001, p=0.0001, and p=0.002, respectively). Using multivariable logistic regression, PBVI provided the best differentiation between TS and controls (AUC 0.84). PBVI was significantly associated with the index of diastolic dysfunction and left atrial strain parameters. In addition, PBVI demonstrated a significant correlation with global T2 mapping (r=0,520, p=0,019). CONCLUSION: PTT and the derived parameters, as assessed using first-pass CMRI, are potential tools for assessing LV diastolic dysfunction in patients with TS

Influence of the technological process on the biochemical composition of fresh roe and bottarga from liza ramada and mugil cephalus

Bottarga is a high-priced delicacy with high nutritional value, and, in Italy, bottarga from mullets has been recognized to be a traditional food product. The flathead grey mullet Mugil cephalus and the thinlip grey mullet Liza ramada are the main cultured grey mullets in the Mediterranean Sea. In this study, fresh roe and bottarga from these two species were investigated to evaluate the influence of the technological process and the species on their biochemical composition and health advantages. The 1 h/200 g salting-out step did not increase the levels of NaCl in the bottarga, although it highly decreased the levels of some heavy metals like Cu and Al. Processing of fresh roe in bottarga led to an essential modification of the lipid fraction, following a general series of monousatturated fatty acid (MUFA)> poliunsutturated fatti acid (PUFA) > saturated fatty acid (SAFA) and an increase in both !3 and !6 in Liza ramada. Moreover, bottarga showed higher levels of squalene and cholesterol and an increased Essential Amino Acid/Total Amino Acid ratio (EAA/TAA) in both species. In addition to the nutritional benefits for the consumer, the process proposed in this study may represent a reliable tool for local producers to obtain a final bottarga with both a reproducible biochemical composition and organoleptic characteristics

The human carotid atherosclerotic plaque: an observational review of histological scoring systems

OBJECTIVE: The atherosclerotic plaque is a complex dynamic pathological lesion of the arterial wall, characterized by multiple elementary lesions of different diagnostic and prognostic significance. Fibrous cap thickness, lipid necrotic core dimension, inflammation, intra-plaque hemorrhage (IPH), plaque neovascularization and endothelial dysfunction (erosions) are generally considered the most relevant morphological details of plaque morphology. In this review, the most relevant features able to discriminate between stable and vulnerable plaques at histological level are discussed. SUBJECTS AND METHODS: Retrospectively, we have evaluated the laboratory results from one hundred old histological samples from patients treated with carotid endarterectomy. These results were analyzed to assess elementary lesions that characterize stable and unstable plaques. RESULTS: A thin fibrous cap (<65 micron), loss of smooth muscle cells, collagen depletion, a large lipid-rich necrotic core, infiltrating macrophages, IPH and intra-plaque vascularization are identified as the most important risk factors associated with plaque rupture. CONCLUSIONS: Immunohistochemistry for smooth muscle actin (smooth muscle cell marker) and for CD68 (marker of monocytes/macrophages) and glycophorin (marker of red blood cells) are suggested as useful tools for an in deep characterization of any carotid plaque and for distinguishing plaque phenotypes at histology. Since patients with a carotid vulnerable plaque are at higher risk of developing vulnerable plaques in other arteries as well, the definition of the vulnerability index is underlined, in order to stratify patients at higher risk for undergoing cardiovascular events

Combined COI barcode-based methods to avoid mislabelling of threatened species of deep-sea skates

Skates are characterised by conservative body morphology which hampers identification and leads to frequent taxonomic confusion and market mislabelling. Accurate specimen classification is crucial for reliable stock assessments and effective conservation plans, otherwise the risk of extinction could be unnoticed. The misclassification issue is evident for the genus Dipturus, distributed worldwide, from the continental shelf and slope to the deep sea. In this study, barcode cytochrome oxidase I gene (COI) sequences were used along with species delimitation and specimen assignment methods to improve taxonomy and zoogeography of species of conservation interest inhabiting the Atlantic Ocean and Mediterranean Sea. In this study, we provided new evidence of the occurence of D. nidarosiensis in the Central-Western Mediterranean Sea and the lack of Atlantic-Mediterranean genetic divergence. The Atlantic endangered species D. laevis and D. batis clustered together under the same molecular operational taxonomic unit (MOTU) with any delimitation methods used, while the assignment approach correctly discriminated specimens into the two species. These results provided evidence that the presence of the barcode gap is not an essential predictor of identification success, but the use of different approaches is crucially needed for specimen classification, especially when threshold- or tree-based methods result less powerful. The analyses also showed how different putative, vulnerable, species dwelling across South-Western Atlantic and South-Eastern Pacific are frequently misidentified in public sequence repositories. Our study emphasised the limits associated to public databases, highlighting the urgency to verify and implement the information deposited therein in order to guarantee accurate species identification and thus effective conservation measures for deep-sea skates

In a three-dimensional reconstructed human epidermis filaggrin-2 is essential for proper cornification

Atopic dermatitis is a chronic inflammatory skin disease with defects in the epidermal barrier. In a cohort of African-American children, a FLG2 nonsense mutation has been associated with the disease. In the epidermis of European patients, the expression of filaggrin-2, the filaggrin-related protein encoded by FLG2, is decreased. To describe the function of filaggrin-2 and evaluate the impact of its deficiency, its expression was downregulated using lentivirus-mediated shRNA interference in a three-dimensional reconstructed human epidermis (RHE) model. This resulted in parakeratosis and a compact stratum corneum, presence of abnormal vesicles inside the corneocytes, increased pH and reduced amounts of free amino acids at the RHE surface, leading to increased sensitivity to UVB radiations. The expression of differentiation markers was slightly modified. However, we observed reduced proteolytic processing of corneodesmosin, hornerin and filaggrin in parallel with reduced amounts of caspase-14 and bleomycin hydrolase. Our data demonstrated that filaggrin-2 is important for a proper cornification and a functional stratum corneum. Its downregulation in atopic patients may be involved in the disease-associated epidermis impairmen

Trace elements and the carotid plaque: the GOOD (Mg, Zn, Se), the UGLY (Fe, Cu), and the BAD (P, Ca)?

Multiple epidemiological studies have suggested that industrialization and progressive urbanization should be considered one of the main factors responsible for the rising of atherosclerosis in the developing world. In this scenario, the role of trace metals in the insurgence and progression of atherosclerosis has not been clarified yet. In this paper, the specific role of selected trace elements (magnesium, zinc, selenium, iron, copper, phosphorus, and calcium) is described by focusing on the atherosclerotic prevention and pathogenesis plaque. For each element, the following data are reported: daily intake, serum levels, intra/extracellular distribution, major roles in physiology, main effects of high and low levels, specific roles in atherosclerosis, possible interactions with other trace elements, and possible influences on plaque development. For each trace element, the correlations between its levels and clinical severity and outcome of COVID-19 are discussed. Moreover, the role of matrix metalloproteinases, a family of zinc-dependent endopeptidases, as a new medical therapeutical approach to atherosclerosis is discussed.Data suggest that trace element status may influence both atherosclerosis insurgence and plaque evolution toward a stable or an unstable status. However, significant variability in the action of these traces is evident: some - including magnesium, zinc, and selenium - may have a protective role, whereas others, including iron and copper, probably have a multi-faceted and more complex role in the pathogenesis of the atherosclerotic plaque. Finally, calcium and phosphorus are implicated in the calcification of atherosclerotic plaques and in the progression of the plaque toward rupture and severe clinical complications. In particular, the role of calcium is debated. Focusing on the COVID-19 pandemia, optimized magnesium and zinc levels are indicated as important protective tools against a severe clinical course of the disease, often related to the ability of SARS-CoV-2 to cause a systemic inflammatory response, able to transform a stable plaque into an unstable one, with severe clinical complications

A Balance of BMP and Notch Activity Regulates Neurogenesis and Olfactory Nerve Formation

Although the function of the adult olfactory system has been thoroughly studied, the molecular mechanisms regulating the initial formation of the olfactory nerve, the first cranial nerve, remain poorly defined. Here, we provide evidence that both modulated Notch and bone morphogenetic protein (BMP) signaling affect the generation of neurons in the olfactory epithelium and reduce the number of migratory neurons, so called epithelioid cells. We show that this reduction of epithelial and migratory neurons is followed by a subsequent failure or complete absence of olfactory nerve formation. These data provide new insights into the early generation of neurons in the olfactory epithelium and the initial formation of the olfactory nerve tract. Our results present a novel mechanism in which BMP signals negatively affect Notch activity in a dominant manner in the olfactory epithelium, thereby regulating neurogenesis and explain why a balance of BMP and Notch activity is critical for the generation of neurons and proper development of the olfactory nerve