A Multiscale Thermo-Fluid Computational Model for a Two-Phase Cooling System

In this paper, we describe a mathematical model and a numerical simulation method for the condenser component of a novel two-phase thermosyphon cooling system for power electronics applications. The condenser consists of a set of roll-bonded vertically mounted fins among which air flows by either natural or forced convection. In order to deepen the understanding of the mechanisms that determine the performance of the condenser and to facilitate the further optimization of its industrial design, a multiscale approach is developed to reduce as much as possible the complexity of the simulation code while maintaining reasonable predictive accuracy. To this end, heat diffusion in the fins and its convective transport in air are modeled as 2D processes while the flow of the two-phase coolant within the fins is modeled as a 1D network of pipes. For the numerical solution of the resulting equations, a Dual Mixed-Finite Volume scheme with Exponential Fitting stabilization is used for 2D heat diffusion and convection while a Primal Mixed Finite Element discretization method with upwind stabilization is used for the 1D coolant flow. The mathematical model and the numerical method are validated through extensive simulations of realistic device structures which prove to be in excellent agreement with available experimental data

Adaptive Immune Responses in Primary Cutaneous Sarcoidosis

Sarcoidosis is a multisystemic inflammatory disorder with cutaneous lesions present in about one-quarter of the patients. Cutaneous lesions have been classified as specific and nonspecific, depending on the presence of nonnecrotizing epithelial cell granulomas on histologic studies. The development and progression of specific cutaneous sarcoidosis involves a complex interaction between cells of the adaptive immune systems, notably T-lymphocytes and dendritic cells. In this paper, we will discuss the role of T-cells and skin dendritic cells in the development of primary cutaneous sarcoidosis and comment on the potential antigenic stimuli that may account for the development of the immunological response. We will further explore the contributions of selected cytokines to the immunopathological process. The knowledge of the adaptive immunological mechanisms operative in cutaneous sarcoidosis may subsequently be useful for identifying prevention and treatment strategies of systemic sarcoidosis

The broad spectrum of lung diseases in primary antibody deficiencies

Human primary immunodeficiency diseases (PIDs) represent a heterogeneous group of more than 350 disorders. They are rare diseases, but their global incidence is more relevant than generally thought. The underlying defect may involve different branches of the innate and/or adaptive immune response. Thus, the clinical picture may range from severe phenotypes characterised by a broad spectrum of infections to milder infectious phenotypes due to more selective (and frequent) immune defects. Moreover, infections may not be the main clinical features in some PIDs that might present with autoimmunity, auto-inflammation and/or cancer. Primary antibody deficiencies (PADs) represent a small percentage of the known PIDs but they are the most frequently diagnosed, particularly in adulthood. Common variable immunodeficiency (CVID) is the most prevalent symptomatic PAD.PAD patients share a significant susceptibility to respiratory diseases that represent a relevant cause of morbidity and mortality. Pulmonary complications include acute and chronic infection-related diseases, such as pneumonia and bronchiectasis. They also include immune-mediated interstitial lung diseases, such as granulomatous-lymphocytic interstitial lung disease (GLILD) and cancer. Herein we will discuss the main pulmonary manifestations of PADs, the associated functional and imaging findings, and the relevant role of pulmonologists and chest radiologists in diagnosis and surveillance

FLUID IN CONVERGENT MARGIN SYSTEMS

[1] A comprehensive geochemical study, including B, Pb, Sr, and Nd isotopes, has been carried out on El Salvador subduction-related lavas. The rocks have arc-type incompatible element distributions with high LILE/HFSE ratios, nearly constant 143Nd/144Nd (≈0.5130), and small differences in 207Pb/204Pb (15.53–15.57), whereas 87Sr/86Sr ranges from 0.7035 to 0.7039. Boron isotopic composition varies widely, between −2.7‰ and +6.3‰. The boron isotope signature points to involvement of fluid inputs from (1) a high-δ11B serpentinite fluid from serpentized mantle wedge dragged beneath the volcanic arc or from the subducting lithosphere and (2) a low-δ11B fluid from the progressive dehydration of subducted altered basaltic crust and/or sediments. The observed sample variability is explained with a model in which different proportions of serpentinite-derived (10–50%) and slab-derived fluids are added to an enriched-DMM source, triggering its partial melting. We suggest a model in which tectonic erosion, i.e., dragging down of slivers of serpentinized upper plate mantle, was responsible for the occurrence of serpentinite reservoir, 11B-enriched in the forearc by shallow fluids

A heterogeneous subcontinental mantle under the African–Arabian plate boundary revealed by boron and radiogenic isotopes

The northern and northwestern margins of the Arabian Plate are a locus of a diffuse and long-lasting (early Miocene to Pleistocene) Na-alkali basaltic volcanism, sourced in the asthenosphere mantle. The upwelling asthenosphere at the Africa–Arabia margin produces very limited magma volumes in the axial zone. Therefore, portions of hot, fertile mantle continue their eastward migration and are stored at shallower depths under the 100-km thick Arabian lithosphere, which is much thinner than the African one (≈175 km): this causes the occurrence and 20-Ma persistence of magma supply under the study area. Erupted basalts sampled a continuous variation of the mantle source, with a striking correlation among temperature, pressure and isotopic composition shifting between two end-members: a 100 km-deep, more depleted source, and a 60 km-deep, more enriched one. In particular, we observed an unusual variation in boron isotopes, which in the oceanic domain does not vary between more depleted and more enriched mantle sources. This study shows that, at least in the considered region, subcontinental mantle is more heterogeneous than the suboceanic one, and able to record for very long times recycling of shallow material

A lithium-ion battery based on a graphene nanoflakes ink anode and a lithium iron phosphate cathode

Li-ion rechargeable batteries have enabled the wireless revolution transforming global communication. Future challenges, however, demands distributed energy supply at a level that is not feasible with the current energy-storage technology. New materials, capable of providing higher energy density are needed. Here we report a new class of lithium-ion batteries based on a graphene ink anode and a lithium iron phosphate cathode. By carefully balancing the cell composition and suppressing the initial irreversible capacity of the anode, we demonstrate an optimal battery performance in terms of specific capacity, i.e. 165 mAhg-1, estimated energy density of about 190 Whkg-1 and life, with a stable operation for over 80 charge-discharge cycles. We link these unique properties to the graphene nanoflake anode displaying crystalline order and high uptake of lithium at the edges, as well as to its structural and morphological optimization in relation to the overall battery composition. Our approach, compatible with any printing technologies, is cheap and scalable and opens up new opportunities for the development of high-capacity Li-ion batteries.Comment: 17 pages, 10 figure

A challenging case of fever of unknown origin (FUO)

Introduction. Fever of unknown origin (FUO) is challenging for physicians as there are more than 200 differential diagnosis of FUO. The diagnosis often requires numerous non-invasive and invasive procedures and sometimes the etiology remains unknown. Clinical case. Our patient is a 24-year-old Caucasian female under contraceptive vaginal ring treatment who presented the first time to the emergency department with fever (38,5°C) and stomach ache. Haematological parameters showed thrombocytosis (728000/mmc) and anemia (10,2 g/dl). Ultrasonography of the abdomen revealed a 4 cm hepatic angioma. She was diagnosed a gastropathy and treated with PPI. Then she was studied deeper because of elevated inflammation markers, persistent thrombocytosis and low-grade fewer combined with fatigue and stomach ache. Despite multiple blood and urine cultures, serology, autoimmune serology, bone marrow biopsy, echocardiography, PET/CT, total body CT, brain MRI scan, transvaginal sonography and gynecological examination no clinical focus could be identified. Esophagogastroduodenoscopy was negative but the histological examination was suggestive of mild celiac disease. Thus, this diagnosis was unlikely because serologic tests and haplotypes DQ2 and DQ8 were negative. Abdomen RMI was suggestive of a 4 cm hepatic adenoma. After surgical resection of the adenoma platelet count normalized and fever disappeared. Conclusions. Hepatic adenoma is an uncommon liver tumor associated with use of oral contraceptive and can be a rare cause of FUO. MRI scan can be a useful tool to detect this tumor

Gastric cancer is the leading cause of death in Italian adult patients with common variable immunodeficiency

An increased prevalence of malignant lymphoma and of gastric cancer has been observed in large cohorts of patients with common variable immunodeficiency (CVID), the most frequently symptomatic primary immunodeficiency. Surveillance strategies for cancers in CVID should be defined based on epidemiological data. Risks and mortality for cancers among 455 Italian patients with CVID were compared to cancer incidence data from the Italian Cancer Registry database. CVID patients showed an increased cancer incidence for all sites combined (Obs = 133, SIR = 2.4; 95%CI = 1.7\u20133.5), due to an excess of non-Hodgkin lymphoma (Obs = 33, SIR = 14.3; 95%CI = 8.4\u201322.6) and of gastric cancer (Obs = 25; SIR = 6.4; 95%CI = 3.2\u201312.5). CVID patients with gastric cancer and lymphoma had a worse survival in comparison to cancer-free CVID (HR: 4.8, 95%CI: 4.2\u201344.4 and HR: 4.2, 95%CI: 2.8\u201344.4). Similar to what observed in other series, CVID-associated lymphomas were more likely to be of B cell origin and often occurred at extra-nodal sites. We collected the largest case-series of gastric cancers in CVID subjects. In contrast to other reports, gastric cancer was the leading cause of death in CVID. Standardized mortality ratio indicated a 10.1-fold excess mortality among CVID patients with gastric cancer. CVID developed gastric cancer 15 years earlier than the normative population, but they had a similar overall survival. Only CVID diagnosed at early stage gastric cancer survived >24 months. Stomach histology from upper endoscopy performed before cancer onset showed areas of atrophic gastritis, intestinal metaplasia or dysplasia. CVID patients might progress rapidly to an advanced cancer stage as shown by patients developing a III-IV stage gastric cancer within 1 year from an endoscopy without signs of dysplasia. Based on high rate of mortality due to gastric cancer in Italian CVID patients, we hereby suggest a strategy aimed at early diagnosis, based on regular upper endoscopy and on Helicobacter pylori infection treatment, recommending an implementation of national guidelines