95 research outputs found
Reply to AlQasimi, E.; Mahdi, T.-F. Comment on âAureli et al. Review of Historical Dam-Break Events and Laboratory Tests on Real Topography for the Validation of Numerical Models. Water 2021, 13, 1968â
This is the reply to the comments by Mahdi (2021) on the classification attributed to the
Lake Ha! Ha! real-field test case by Aureli et al. (2021) in their review of historical dam-break
events useful for the validation of dam-break numerical models. While admitting that this test case
is affected by the data shortcomings reported by the Discusser, in the authorsâ opinion, it should
remain included in the group of well-documented test cases due to the large and complete dataset
available in digital format. This conclusion is also supported by the fact that the Lake Ha! Ha! case
was chosen as a benchmark in the framework of the 2001â2004 IMPACT (Investigation of Extreme
Flood Processes and Uncertainty) European project and was then widely used in the literature for the
validation of one-dimensional and two-dimensional geomorphic flood models
Review of Historical Dam-Break Events and Laboratory Tests on Real Topography for the Validation of Numerical Models
Dam break inundation mapping is essential for risk management and mitigation, emergency
action planning, and potential consequences assessment. To quantify flood hazard associated
with dam failures, flooding variables must be predicted by efficient and robust numerical models
capable to effectively cope with the computational difficulties posed by complex flows on real topographies.
Validation against real-field data of historical dam-breaks is extremely useful to verify
modelsâ capabilities and accuracy. However, such catastrophic events are rather infrequent, and
available data on the breaching mechanism and downstream flooding are usually inaccurate and
incomplete. Nevertheless, in some cases, real-field data collected after the event (mainly breach
size, maximum water depths and flood wave arrival times at selected locations, water marks, and
extent of flooded areas) are adequate to set up valuable and significant test cases, provided that all
other data required to perform numerical simulations are available (mainly topographic data of the
floodable area and input parameters defining the dam-break scenario). This paper provides a review
of the historical dam-break events for which real-field datasets useful for validation purposes can
be retrieved in the literature. The resulting real-field test cases are divided into well-documented
test cases, for which extensive and complete data are already available, and cases with partial or
inaccurate datasets. Type and quality of the available data are specified for each case. Finally, validation
data provided by dam-break studies on physical models reproducing real topographies are
presented and discussed. This review aims at helping dam-break modelers: (a) to select the most
suitable real-field test cases for validating their numerical models, (b) to facilitate data access by
indicating relevant bibliographic references, and (c) to identify test cases of potential interest worthy
of further research
Hydrological and Hydraulic Flood Hazard Modeling in Poorly Gauged Catchments: An Analysis in Northern Italy
Flood hazard is assessed for a watershed with scarce hydrological data in the lower plain
of Northern Italy, where the current defense system is inadequate to protect a highly populated
urban area located at a river confluence and crossed by numerous bridges. An integrated approach
is adopted. Firstly, to overcome the scarcity of data, a regional flood frequency analysis is performed
to derive synthetic design hydrographs, with an original approach to obtain the flow reduction
curve from recorded water stages. The hydrographs are then imposed as upstream boundary
conditions for hydraulic modeling using the fully 2D shallow-water model PARFLOOD with the
recently proposed inclusion of bridges. Highâresolution simulations of the potential flooding in the
urban center and surrounding areas are, therefore, performed as a novel extensive application of a
truly 2D framework for bridge modeling. Moreover, simulated flooded areas and water levels, with
and without bridges, are compared to quantify the interference of the crossing structures and to
assess the effectiveness of a structural measure for flood hazard reduction, i.e., bridge adaptation.
This work shows how the use of an integrated hydrologicalâhydraulic approach can be useful for
infrastructure design and civil protection purposes in a poorly gauged watershed
Experimental and numerical evaluation of the force due to the impact of a dam-break wave on a structure
Flood events caused by the collapse of dams or river levees can have damaging consequences on buildings and infrastructure located in prone areas. Accordingly, a careful prediction of the hydrodynamic load acting on structures is important for flood hazard assessment and potential damage evaluation. However, this represents a challenging task and requires the use of suitable mathematical models. This paper investigates the capability of three different models, i.e. a 2D depth-averaged model, a 3D Eulerian two-phase model, and a 3D Smoothed Particle Hydrodynamics (SPH) model, to estimate the impact load exerted by a dam-break wave on an obstacle. To this purpose, idealised dam-break experiments were carried out by generating a flip-through impact against a rigid squat structure, and measurements of the impact force were obtained directly by using a load cell. The dynamics of the impact event was analyzed and related to the measured load time history. A repeatability analysis was performed due to the great variability typically shown by impact phenomena, and a confidence range was estimated. The comparison between numerical results and experimental data shows the capability of 3D models to reproduce the key features of the flip-through impact. The 2D modelling based on the shallow water approach is not entirely suitable to accurately reproduce the load hydrograph and predict the load peak values; this difficulty increases with the strength of the wave impact. Nevertheless, the error in the peak load estimation is in the order of 10% only, thus the 2D approach may be considered appropriate for practical applications. Moreover, when the shallow water approximation is expected to work well, 2D results are comparable with the experimental data, as well as with the numerical predictions of far more sophisticated and computationally demanding 3D solvers. All the numerical models overestimate the falling limb of the load hydrograph after the impact. The SPH model ensures good evaluation of the long-time load impulse. The 2D shallow water solver and the 3D Eulerian model are less accurate in predicting the load impulse but provide similar results. A sensitivity analysis with respect to the model parameters allows to assess model uncertainty
A GPU-Accelerated Shallow-Water Scheme for Surface Runoff Simulations
The capability of a GPU-parallelized numerical scheme to perform accurate and fast
simulations of surface runo in watersheds, exploiting high-resolution digital elevation models
(DEMs), was investigated. The numerical computations were carried out by using an explicit finite
volume numerical scheme and adopting a recent type of grid called Block-Uniform Quadtree (BUQ),
capable of exploiting the computational power of GPUs with negligible overhead. Moreover, stability
and zero mass error were ensured, even in the presence of very shallow water depth, by introducing
a proper reconstruction of conserved variables at cell interfaces, a specific formulation of the slope
source term and an explicit discretization of the friction source term. The 2D shallow water model
was tested against two dierent literature tests and a real event that recently occurred in Italy for
which field data is available. The influence of the spatial resolution adopted in dierent portions of
the domain was also investigated for the last test. The achieved low ratio of simulation to physical
times, in some cases less than 1:20, opens new perspectives for flood management strategies. Based
on the result of such models, emergency plans can be designed in order to achieve a significant
reduction in the economic losses generated by flood events
Distribution of epidemic clonal genetic markers among Listeria monocytogenes 4b isolates.
Recent genome sequencing of isolates of Listeria monocytogenes serotype 4b implicated in some major outbreaks of foodborne listeriosis has revealed unique genetic markers in these isolates. The isolates were grouped into two distinct epidemic clones, ECI and ECII. In the present study, selected ECI- and ECII-specific genetic markers were detected in 16 and 15 of 89 L. monocytogenes 4b isolates, respectively. The ECI markers were found in 6 of 34 clinical isolates, 9 of 50 food isolates, and 1 of 5 environmental isolates, and the ECII markers were detected in 7 of 34 clinical isolates, 7 of 50 food isolates, and 1 of 5 environmental isolates. Hence, of the isolates with the epidemic clonal genetic markers, 38% (13 of 34) were of clinical origin, 32% (16 of 50) were of food origin, and 40% (2 of 5) were of environmental origin. The predominance of the epidemic clonal markers among the clinical and environmental isolates supports the hypothesis that these markers are correlated with the pathogenic potential of strains and with their environmental persistence. Several isolates had only one epidemic clonal marker, either the ECI-specific marker 133 or the ECII-specific marker 4bSF18. Pulsed-field gel electrophoresis analysis revealed higher genomic diversity among the strains with ECII-like characteristics than among those strains carrying the ECI-specific genetic markers
Novel bicistronic lentiviral vectors correct ÎČ-Hexosaminidase deficiency in neural and hematopoietic stem cells and progeny: implications for in vivo and ex vivo gene therapy of GM2 gangliosidosis.
Abstract The favorable outcome of in vivo and ex vivo gene therapy approaches in several Lysosomal Storage Diseases suggests that these treatment strategies might equally benefit GM2 gangliosidosis. Tay-Sachs and Sandhoff disease (the main forms of GM2 gangliosidosis) result from mutations in either the HEXA or HEXB genes encoding, respectively, the α- or ÎČ-subunits of the lysosomal ÎČ-Hexosaminidase enzyme. In physiological conditions, α- and ÎČ-subunits combine to generate ÎČ-Hexosaminidase A (HexA, αÎČ) and ÎČ-Hexosaminidase B (HexB, ÎČÎČ). A major impairment to establishing in vivo or ex vivo gene therapy for GM2 gangliosidosis is the need to synthesize the α- and ÎČ-subunits at high levels and with the correct stoichiometric ratio, and to safely deliver the therapeutic products to all affected tissues/organs. Here, we report the generation and in vitro validation of novel bicistronic lentiviral vectors (LVs) encoding for both the murine and human codon optimized Hexa and Hexb genes. We show that these LVs drive the safe and coordinate expression of the α- and ÎČ-subunits, leading to supranormal levels of ÎČ-Hexosaminidase activity with prevalent formation of a functional HexA in SD murine neurons and glia, murine bone marrow-derived hematopoietic stem/progenitor cells (HSPCs), and human SD fibroblasts. The restoration/overexpression of ÎČ-Hexosaminidase leads to the reduction of intracellular GM2 ganglioside storage in transduced and in cross-corrected SD murine neural progeny, indicating that the transgenic enzyme is secreted and functional. Importantly, bicistronic LVs safely and efficiently transduce human neurons/glia and CD34+ HSPCs, which are target and effector cells, respectively, in prospective in vivo and ex vivo GT approaches. We anticipate that these bicistronic LVs may overcome the current requirement of two vectors co-delivering the α- or ÎČ-subunits genes. Careful assessment of the safety and therapeutic potential of these bicistronic LVs in the SD murine model will pave the way to the clinical development of LV-based gene therapy for GM2 gangliosidosis
Phosphorylation of FAM134C by CK2 controls starvation-induced ER-phagy.
Selective degradation of the endoplasmic reticulum (ER) via autophagy (ER-phagy) is initiated by ER-phagy receptors, which facilitate the incorporation of ER fragments into autophagosomes. FAM134 reticulon family proteins (FAM134A, FAM134B, and FAM134C) are ER-phagy receptors with structural similarities and nonredundant functions. Whether they respond differentially to the stimulation of ER-phagy is unknown. Here, we describe an activation mechanism unique to FAM134C during starvation. In fed conditions, FAM134C is phosphorylated by casein kinase 2 (CK2) at critical residues flanking the LIR domain. Phosphorylation of these residues negatively affects binding affinity to the autophagy proteins LC3. During starvation, mTORC1 inhibition limits FAM134C phosphorylation by CK2, hence promoting receptor activation and ER-phagy. Using a novel tool to study ER-phagy in vivo and FAM134C knockout mice, we demonstrated the physiological relevance of FAM134C phosphorylation during starvation-induced ER-phagy in liver lipid metabolism. These data provide a mechanistic insight into ER-phagy regulation and an example of autophagy selectivity during starvation.We thank G. Diez Roux and P. Ashley-Norman for critical reading of the manuscript. We thank the microscopy, MS, advanced histopathology, and FACS facilities at TIGEM Institute. We thank E. Nusco for helping us with AAV injections. Funding: This work was supported by European Research Council (ERC) (714551), Telethon intramural grants, and Associazione Italiana per la Ricerca sul Cancro (AIRC) (IG 2015 Id 17717) (to C.S.) and Telethon Foundation (TMPGCBX16TT), AFM Telethon (Trampoline Grant), and AIRC (MFAG-2020-24856) (to P.G.). G.D.L. is a recipient of AIRC fellowship âFrancesco Alicinoâ (25407). V.L. acknowledges funding from the ERC (101001784), the Italian MIUR-PRIN 2017 (2017FJZZRC), and the Swiss National Supercomputing Center (CSCS) (project ID u8). The work of A.S. was supported by the German Research Foundation DFG (SFB1177/2 and WO210/20-2) and the Dr. Rolf M. Schwiete Stiftung (13/2017). A.E. is supported by the RETOS projects Programme of Spanish Ministry of Science, Innovation and Universities, Spanish State Research Agency (grants SAF2015-67538-R and PID2019-104012RB-I00), and the ERC (638891). A.B.P.-G. is a recipient of Ph.D. fellowship from MICIU/AEI (BES-2017-081381). A.R. is a recipient of Umberto Veronesi Foundation postdoctoral fellowship. Author contributions: G.D.L. and F.I. performed most of the experiments. F.I. and A.B.P.-G. performed in vivo experiments. M.M. performed mutagenesis experiments. S.A. and V.L. performed LC3-FAM134C binding analysis. C.P.Q.M. performed in vitro phosphorylation assays. L.C. analyzed CK2 substrate phosphorylation. F.S., A.P., C.C., and A.S. analyzed proteomic data. G.N. provided critical suggestions. A.R. performed proteomic experiments. A.E. supervised in vivo experiments. M.R., L.A.P., and O.M. supervised CK2 experiments. C.S. designed the study. P.G. and C.S. conceived and supervised the experiments. C.S., P.G., V.L., and M.R. wrote the paper. G.D.L. and F.I. prepared the figures. All the authors read the manuscript. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials.S
Direct CD32 T-cell cytotoxicity: implications for breast cancer prognosis and treatment
The FcγRII (CD32) ligands are IgFc fragments and pentraxins. The existence of additional ligands is unknown. We engineered T cells with human chimeric receptors resulting from the fusion between CD32 extracellular portion and transmembrane CD8α linked toCD28/ζ chain intracellular moiety (CD32-CR). Transduced T cells
recognized three breast cancer (BC) and one colon cancer cell line
among 15 tested in the absence of targeting antibodies. Sensitive
BC cell conjugation with CD32-CR T cells induced CD32 polarization
and down-regulation, CD107a release, mutual elimination,
and proinflammatory cytokine production unaffected by human
IgGs but enhanced by cetuximab. CD32-CR T cells protected immunodeficient
mice from subcutaneous growth of MDA-MB-468
BC cells. RNAseq analysis identified a 42 gene fingerprint predicting
BC cell sensitivity and favorable outcomes in advanced BC.
ICAM1 was a major regulator of CD32-CR T cellâmediated cytotoxicity.
CD32-CR T cells may help identify cell surface CD32 ligand(s)
and novel prognostically relevant transcriptomic signatures and
develop innovative BC treatments
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