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Surfaces close to the Severi lines [article]

Federico Cesare Giorgio Conti
2021 arXiv   pre-print
In this Thesis we study surfaces of general type with maximal Albanese dimension for which the quantity K_X^2-4χ(𝒪_X)-4(q-2) vanishes or is "small", that is surfaces close to the Severi lines.  ...  . . . . 118 5 Severi type inequalities and surfaces close to the Severi lines in positive characteristic 123 5.1 Severi type inequalities in characteristic different from 2 . . . 123 5.2 Surfaces close  ...  Severi inequality In this section we give the proof of the Severi inequality for surfaces of general type with maximal Albanese dimension.  ... 
arXiv:2107.09748v1 fatcat:n6gibgxtb5hbpngo654fib3qwa

Subpopulation Data Poisoning Attacks [article]

Matthew Jagielski, Giorgio Severi, Niklas Pousette Harger, Alina Oprea
2021 arXiv   pre-print
Machine learning systems are deployed in critical settings, but they might fail in unexpected ways, impacting the accuracy of their predictions. Poisoning attacks against machine learning induce adversarial modification of data used by a machine learning algorithm to selectively change its output when it is deployed. In this work, we introduce a novel data poisoning attack called a subpopulation attack, which is particularly relevant when datasets are large and diverse. We design a modular
more » ... sign a modular framework for subpopulation attacks, instantiate it with different building blocks, and show that the attacks are effective for a variety of datasets and machine learning models. We further optimize the attacks in continuous domains using influence functions and gradient optimization methods. Compared to existing backdoor poisoning attacks, subpopulation attacks have the advantage of inducing misclassification in naturally distributed data points at inference time, making the attacks extremely stealthy. We also show that our attack strategy can be used to improve upon existing targeted attacks. We prove that, under some assumptions, subpopulation attacks are impossible to defend against, and empirically demonstrate the limitations of existing defenses against our attacks, highlighting the difficulty of protecting machine learning against this threat.
arXiv:2006.14026v3 fatcat:4ispwapnizcj5fkpxio4e4knjq

Malrec: Compact Full-Trace Malware Recording for Retrospective Deep Analysis [chapter]

Giorgio Severi, Tim Leek, Brendan Dolan-Gavitt
2018 Lecture Notes in Computer Science  
Malware sandbox systems have become a critical part of the Internet's defensive infrastructure. These systems allow malware researchers to quickly understand a sample's behavior and effect on a system. However, current systems face two limitations: first, for performance reasons, the amount of data they can collect is limited (typically to system call traces and memory snapshots). Second, they lack the ability to perform retrospective analysis-that is, to later extract features of the malware's
more » ... es of the malware's execution that were not considered relevant when the sample was originally executed. In this paper, we introduce a new malware sandbox system, Malrec, which uses whole-system deterministic record and replay to capture high-fidelity, whole-system traces of malware executions with low time and space overheads. We demonstrate the usefulness of this system by presenting a new dataset of 66,301 malware recordings collected over a two-year period, along with two preliminary analyses that would not be possible without full traces: an analysis of kernel mode malware and exploits, and a fine-grained malware family classification based on textual memory access contents. The Malrec system and dataset can help provide a standardized benchmark for evaluating the performance of future dynamic analyses.
doi:10.1007/978-3-319-93411-2_1 fatcat:obtupl6bcrbcpmsdselnd5wyem

Surgical approach to giant ovarian masses in adolescents: technical considerations

Giorgio Persano, Elisa Severi, Noemi Cantone, Filippo Incerti, Enrico Ciardini, Bruno Noccioli
2018 Pediatric Reports  
Ovarian neoplasms arising from the surface epithelium are rare in the pediatric population; their knowledge is therefore limited and the appropriate management is poorly defined. We describe our experience and suggest our surgical approach to adolescents affected by voluminous ovarian masses. Two 15-year-old adolescents were admitted to our institution in 2017 for multilobulated, fluid-filled masses measuring over 30 cm arising from the ovaries. The cystic component was drained intraoperatively
more » ... ed intraoperatively with a spillage-free technique, consisting in the application of a sterile autoadhesive transparent drape on the cyst and the insertion of a 12 Ch pleural drain, secured with a purse-string suture. Unilateral salpingo-oophorectomy was then carried out. Histology revealed mucinous cystadenoma in both patients. Surgical treatment of ovarian masses should aim at both radically excising the tumor and preserving the fertility of the patients. Decompression with spillage-free techniques can be useful to achieve radical therapy with limited manipulation of tissues.
doi:10.4081/pr.2018.7752 pmid:30363636 pmcid:PMC6178927 fatcat:xkjqdzudg5a55dly3kd72heveq

Explanation-Guided Backdoor Poisoning Attacks Against Malware Classifiers [article]

Giorgio Severi, Jim Meyer, Scott Coull, Alina Oprea
2021 arXiv   pre-print
Training pipelines for machine learning (ML) based malware classification often rely on crowdsourced threat feeds, exposing a natural attack injection point. In this paper, we study the susceptibility of feature-based ML malware classifiers to backdoor poisoning attacks, specifically focusing on challenging "clean label" attacks where attackers do not control the sample labeling process. We propose the use of techniques from explainable machine learning to guide the selection of relevant
more » ... of relevant features and values to create effective backdoor triggers in a model-agnostic fashion. Using multiple reference datasets for malware classification, including Windows PE files, PDFs, and Android applications, we demonstrate effective attacks against a diverse set of machine learning models and evaluate the effect of various constraints imposed on the attacker. To demonstrate the feasibility of our backdoor attacks in practice, we create a watermarking utility for Windows PE files that preserves the binary's functionality, and we leverage similar behavior-preserving alteration methodologies for Android and PDF files. Finally, we experiment with potential defensive strategies and show the difficulties of completely defending against these attacks, especially when the attacks blend in with the legitimate sample distribution.
arXiv:2003.01031v3 fatcat:gbvwryhwzfdhxor2x6al5krkwe

Multifrequency bioelectric impedance measurements for predicting body water compartments in duchenne muscular dystrophy

Giorgio Bedogni, Luciano Merlini, Alessandro Ballestrazzi, Sabrina Severi, Nino Battistini
1996 Neuromuscular Disorders  
Body hydration and extra-to intra-cellular water ratio (ECW: ICW) have been studied in 12 duchenne muscular dystrophy (DMD) patients and 15 healthy controls. Subjects underwent total body water (TBW) and extracellular water (ECW) assessment by deuterium and bromide dilution, respectively. Multifrequency bioelectric impedance analysis (MFBIA) was performed on all subjects with the aim to establish its accuracy in predicting TBW and ECW in DMD. Body hydration was lower (51.8 ± 2.8 vs 58.5 ± 5.9%,
more » ... 2.8 vs 58.5 ± 5.9%, P < 0.01) and the ECW: ICW ratio higher (1.15 ±0.25 vs 0.70 ±0.23, P < 0.001) in DMD than in control subjects. Hence, control-generated formulae for predicting TBW and ECW from MFBIA gave inaccurate results in DMD subjects. Population-specific formulae were developed to obtain an accurate prediction of body water compartments in DMD patients.
doi:10.1016/0960-8966(95)00015-1 pmid:8845719 fatcat:rp372w4k4nbxdk6rnj6cxh6zra

The RNA editing enzyme APOBEC1 induces somatic mutations and a compatible mutational signature is present in esophageal adenocarcinomas

Giulia Saraconi, Francesco Severi, Cesare Sala, Giorgio Mattiuz, Silvestro G Conticello
2014 Genome Biology  
The AID/APOBECs are deaminases that act on cytosines in a diverse set of pathways and some of them have been linked to the onset of genetic alterations in cancer. Among them, APOBEC1 is the only family member to physiologically target RNA, as the catalytic subunit in the Apolipoprotein B mRNA editing complex. APOBEC1 has been linked to cancer development in mice but its oncogenic mechanisms are not yet well understood. Results: We analyze whether expression of APOBEC1 induces a mutator
more » ... a mutator phenotype in vertebrate cells, likely through direct targeting of genomic DNA. We show its ability to increase the inactivation of a stably inserted reporter gene in a chicken cell line that lacks any other AID/APOBEC proteins, and to increase the number of imatinib-resistant clones in a human cellular model for chronic myeloid leukemia through induction of mutations in the BCR-ABL1 fusion gene. Moreover, we find the presence of an AID/APOBEC mutational signature in esophageal adenocarcinomas, a type of tumor where APOBEC1 is expressed, that mimics the one preferred by APOBEC1 in vitro. Conclusions: Our findings suggest that the ability of APOBEC1 to trigger genetic alterations represents a major layer in its oncogenic potential. Such APOBEC1-induced mutator phenotypes could play a role in the onset of esophageal adenocarcinomas. APOBEC1 could be involved in cancer promotion at the very early stages of carcinogenesis, as it is highly expressed in Barrett's esophagus, a condition often associated with esophageal adenocarcinoma.
doi:10.1186/s13059-014-0417-z pmid:25085003 pmcid:PMC4144122 fatcat:g72uknydhfacjlsbrou75nsjty

The RNA editing enzyme APOBEC1 induces somatic mutations and a compatible mutational signature is present in esophageal adenocarcinomas

Giulia Saraconi, Francesco Severi, Cesare Sala, Giorgio Mattiuz, Silvestro G Conticello
2014 Genome Biology  
The AID/APOBECs are deaminases that act on cytosines in a diverse set of pathways and some of them have been linked to the onset of genetic alterations in cancer. Among them, APOBEC1 is the only family member to physiologically target RNA, as the catalytic subunit in the Apolipoprotein B mRNA editing complex. APOBEC1 has been linked to cancer development in mice but its oncogenic mechanisms are not yet well understood. Results: We analyze whether expression of APOBEC1 induces a mutator
more » ... a mutator phenotype in vertebrate cells, likely through direct targeting of genomic DNA. We show its ability to increase the inactivation of a stably inserted reporter gene in a chicken cell line that lacks any other AID/APOBEC proteins, and to increase the number of imatinib-resistant clones in a human cellular model for chronic myeloid leukemia through induction of mutations in the BCR-ABL1 fusion gene. Moreover, we find the presence of an AID/APOBEC mutational signature in esophageal adenocarcinomas, a type of tumor where APOBEC1 is expressed, that mimics the one preferred by APOBEC1 in vitro. Conclusions: Our findings suggest that the ability of APOBEC1 to trigger genetic alterations represents a major layer in its oncogenic potential. Such APOBEC1-induced mutator phenotypes could play a role in the onset of esophageal adenocarcinomas. APOBEC1 could be involved in cancer promotion at the very early stages of carcinogenesis, as it is highly expressed in Barrett's esophagus, a condition often associated with esophageal adenocarcinoma.
doi:10.1186/preaccept-3516273912883547 pmid:25085003 pmcid:PMC4144122 fatcat:xobmgvgtc5bzhdvyord7ykhgyy

Erratum to: The RNA editing enzyme APOBEC1 induces somatic mutations and a compatible mutational signature is present in esophageal adenocarcinomas

Giulia Saraconi, Francesco Severi, Cesare Sala, Giorgio Mattiuz, Silvestro G Conticello
2014 Genome Biology  
The AID/APOBECs are deaminases that act on cytosines in a diverse set of pathways and some of them have been linked to the onset of genetic alterations in cancer. Among them, APOBEC1 is the only family member to physiologically target RNA, as the catalytic subunit in the Apolipoprotein B mRNA editing complex. APOBEC1 has been linked to cancer development in mice but its oncogenic mechanisms are not yet well understood. Results: We analyze whether expression of APOBEC1 induces a mutator
more » ... a mutator phenotype in vertebrate cells, likely through direct targeting of genomic DNA. We show its ability to increase the inactivation of a stably inserted reporter gene in a chicken cell line that lacks any other AID/APOBEC proteins, and to increase the number of imatinib-resistant clones in a human cellular model for chronic myeloid leukemia through induction of mutations in the BCR-ABL1 fusion gene. Moreover, we find the presence of an AID/APOBEC mutational signature in esophageal adenocarcinomas, a type of tumor where APOBEC1 is expressed, that mimics the one preferred by APOBEC1 in vitro. Conclusions: Our findings suggest that the ability of APOBEC1 to trigger genetic alterations represents a major layer in its oncogenic potential. Such APOBEC1-induced mutator phenotypes could play a role in the onset of esophageal adenocarcinomas. APOBEC1 could be involved in cancer promotion at the very early stages of carcinogenesis, as it is highly expressed in Barrett's esophagus, a condition often associated with esophageal adenocarcinoma.
doi:10.1186/s13059-014-0497-9 fatcat:pkxf353sijdcreyjgdjuavtdqq

Common features between neoplastic and preneoplastic lesions of the biliary tract and the pancreas

Piera Zaccari, Vincenzo Cardinale, Carola Severi, Federica Pedica, Guido Carpino, Eugenio Gaudio, Claudio Doglioni, Maria Chiara Petrone, Domenico Alvaro, Paolo Giorgio Arcidiacono, Gabriele Capurso
2019 World Journal of Gastroenterology  
the bile duct system and pancreas show many similarities due to their anatomical proximity and common embryological origin. Consequently, preneoplastic and neoplastic lesions of the bile duct and pancreas share analogies in terms of molecular, histological and pathophysiological features. Intraepithelial neoplasms are reported in biliary tract, as biliary intraepithelial neoplasm (BilIN), and in pancreas, as pancreatic intraepithelial neoplasm (PanIN). Both can evolve to invasive carcinomas,
more » ... sive carcinomas, respectively cholangiocarcinoma (CCA) and pancreatic ductal adenocarcinoma (PDAC). Intraductal papillary neoplasms arise in biliary tract and pancreas. Intraductal papillary neoplasm of the biliary tract (IPNB) share common histologic and phenotypic features such as pancreatobiliary, gastric, intestinal and oncocytic types, and biological behavior with the pancreatic counterpart, the intraductal papillary mucinous neoplasm of the pancreas (IPMN). All these neoplastic lesions exhibit similar immunohistochemical phenotypes, suggesting a common carcinogenic process. Indeed, CCA and PDAC display similar clinic-pathological features as growth pattern, poor response to conventional chemotherapy and radiotherapy and, as a consequence, an unfavorable prognosis. The objective of this review is to discuss similarities and differences between the neoplastic lesions of the pancreas and biliary tract with potential implications on a common origin from similar stem/progenitor cells.
doi:10.3748/wjg.v25.i31.4343 pmid:31496617 pmcid:PMC6710182 fatcat:hxenpk226zanrgof4d47kwux7e

Brown adipose tissue whitening leads to brown adipocyte death and adipose tissue inflammation

Petra Kotzbeck, Antonio Giordano, Eleonora Mondini, Incoronata Murano, Ilenia Severi, Wiebe Venema, Maria Paola Cecchini, Erin E. Kershaw, Giorgio Barbatelli, Guenter Haemmerle, Rudolf Zechner, Saverio Cinti
2018 Journal of Lipid Research  
doi:10.1194/jlr.m079665 pmid:29599420 fatcat:ortwiryz4zb3fop35eptgf2piq

Irisin prevents and restores bone loss and muscle atrophy in hind-limb suspended mice

Graziana Colaianni, Teresa Mongelli, Concetta Cuscito, Paolo Pignataro, Luciana Lippo, Giovanna Spiro, Angela Notarnicola, Ilenia Severi, Giovanni Passeri, Giorgio Mori, Giacomina Brunetti, Biagio Moretti (+6 others)
2017 Scientific Reports  
We previously showed that Irisin, a myokine released from skeletal muscle after physical exercise, plays a central role in the control of bone mass. Here we report that treatment with recombinant Irisin prevented bone loss in hind-limb suspended mice when administered during suspension (preventive protocol) and induced recovery of bone mass when mice were injected after bone loss due to a suspension period of 4 weeks (curative protocol). MicroCT analysis of femurs showed that r-Irisin preserved
more » ... r-Irisin preserved both cortical and trabecular bone mineral density, and prevented a dramatic decrease of the trabecular bone volume fraction. Moreover, r-Irisin protected against muscle mass decline in the hindlimb suspended mice, and maintained the fiber cross-sectional area. Notably, the decrease of myosin type II expression in unloaded mice was completely prevented by r-Irisin administration. Our data reveal for the first time that Irisin retrieves disuse-induced bone loss and muscle atrophy. These findings may lead to development of an Irisin-based therapy for elderly immobile osteoporotic and physically disable patients, and might represent a countermeasure for astronauts subjected to microgravity-induced bone and muscle losses. Disuse osteoporosis is a worldwide problem that affects patients suffering from poor walking and impaired physical ability up to immobility. Elderly, para-or hemiplegia after spinal cord injury or stroke 1, 2 and vegetative states 3 are examples of prolonged skeletal unloading that lead to decrease cortical mineral density and impairment of trabecular bone microarchitecture, resulting in skeletal fragility and increased fracture risk 4 . Data on fracture frequency in bedridden patients showed that 3.6% of 500 patients suffered from spontaneous fractures during a 6-year follow-up period 4 , suggesting that disuse osteoporosis is a clinically relevant issue for its related morbidity and mortality as well as for health-care costs. Another well-documented unloading condition affecting the skeleton is the long exposure to microgravity during spaceflight. Astronauts are prone to bone loss at a rate of 0.5% to 1.5% per month 5 , equally to the loss found in postmenopausal women in 1 year 6, 7 . Even the return to Earth cannot fully restore bone loss of astronauts, who partially recover bone mineral density (BMD) in 1 year after returning from 4 to 6 months on the International space station 8 . As a result of weight-bearing removal, pathological changes affecting the skeleton are further exacerbated by concomitant onset of muscle atrophy. Indeed, astronauts experienced 4% to 8% muscle volume decline after the first week of shuttle mission 9 and up to 10% reduction in strength of knee extensor muscles and 8% decrease in muscle fiber cross-sectional area (CSA) has been found after 17 days in microgravity environment 10 . Thus, the influence of microgravity has been studied in order to investigate the myosin phenotype Published: xx xx xxxx OPEN www.nature.com/scientificreports/ 2 Scientific RepoRts | 7: 2811 |
doi:10.1038/s41598-017-02557-8 pmid:28588307 pmcid:PMC5460172 fatcat:7mmlnarbxvgwjlnnve7sj27qza

Muscle and adipose tissue morphology, insulin sensitivity and beta-cell function in diabetic and nondiabetic obese patients: effects of bariatric surgery

Stefania Camastra, Alessandra Vitali, Marco Anselmino, Amalia Gastaldelli, Rosario Bellini, Rossana Berta, Ilenia Severi, Simona Baldi, Brenno Astiarraga, Giorgio Barbatelli, Saverio Cinti, Ele Ferrannini
2017 Scientific Reports  
Obesity is characterized by insulin-resistance (IR), enhanced lipolysis, and ectopic, inflamed fat. We related the histology of subcutaneous (SAT), visceral fat (VAT), and skeletal muscle to the metabolic abnormalities, and tested their mutual changes after bariatric surgery in type 2 diabetic (T2D) and weight-matched non-diabetic (ND) patients. We measured IR (insulin clamp), lipolysis ( 2 H 5 -glycerol infusion), ß-cell glucose-sensitivity (ß-GS, mathematical modeling), and VAT, SAT, and
more » ... VAT, SAT, and rectus abdominis histology (light and electron microscopy). Presurgery, SAT and VAT showed signs of fibrosis/necrosis, small mitochondria, free interstitial lipids, thickened capillary basement membrane. Compared to ND, T2D had impaired ß-GS, intracapillary neutrophils and higher intramyocellular fat, adipocyte area in VAT, crown-like structures (CLS) in VAT and SAT with rare structures (cyst-like) ~10-fold larger than CLS. Fat expansion was associated with enhanced lipolysis and IR. VAT histology and intramyocellular fat were related to impaired ß-GS. Postsurgery, IR and lipolysis improved in all, ß-GS improved in T2D. Muscle fat infiltration was reduced, adipocytes were smaller and richer in mitochondria, and CLS density in SAT was reduced. In conclusion, IR improves proportionally to weight loss but remains subnormal, whilst SAT and muscle changes disappear. In T2D postsurgery, some VAT pathology persists and beta-cell dysfunction improves but is not normalized. Obesity is associated with chronic low-grade inflammation in adipose tissue, which accompanies, and may contribute to the development of, insulin resistance and type 2 diabetes (T2D) 1 . In obese mice and humans, as hypertrophic adipocytes become insulin resistant, their lipolytic activity is accelerated; as a consequence, nonesterified fatty acids (NEFA) flux is partially shunted away from adipose tissue toward ectopic depots (in liver, muscle, and other organs). These changes in the metabolic phenotype are accompanied by an increased expression and release of inflammatory cytokines 2 , which further stimulate lipolysis. In addition, expanded adipose depots are infiltrated by macrophages and T cells, expressing high levels of inflammatory cytokines 3 . Macrophage infiltration is positively related to the size of adipocytes and coincides with the appearance of insulin resistance as macrophages alter the levels of insulin signalling molecules and GLUT4 and inhibit insulin action 4 . In obese humans, adipocyte death is an accelerated phenomenon 5 . In both lean and obese mice over 90% of macrophages infiltrating the adipose tissue are found around dead adipocytes, forming characteristic structures termed 'crown-like structures' (CLS). Density of CLS is positively related to adipocyte size, independent of obesity status 6 . Adipose tissue from humans shows similar features 6 . Macrophages penetrate adipose tissue to remove remnants of dead adipocytes; due to the small size of macrophages and the time required for the dead adipocyte removal process, chronic low-grade inflammation is induced, similar to that observed in foreign body reactions 7, 8 . Published: xx xx xxxx OPEN www.nature.com/scientificreports/ 2 SCIENtIfIC REpoRTS | 7: 9007 |
doi:10.1038/s41598-017-08444-6 pmid:28827671 pmcid:PMC5566429 fatcat:2epybe4tcngglo4reyikv45qga

Publisher Correction: Muscle and adipose tissue morphology, insulin sensitivity and beta-cell function in diabetic and nondiabetic obese patients: effects of bariatric surgery

Stefania Camastra, Alessandra Vitali, Marco Anselmino, Amalia Gastaldelli, Rosario Bellini, Rossana Berta, Ilenia Severi, Simona Baldi, Brenno Astiarraga, Giorgio Barbatelli, Saverio Cinti, Ele Ferrannini
2018 Scientific Reports  
doi:10.1038/s41598-018-25221-1 pmid:29784999 pmcid:PMC5962565 fatcat:4wdazaffb5fvloov6bm6fhr7ba

High-Fat Diet Impairs Mouse Median Eminence: A Study by Transmission and Scanning Electron Microscopy Coupled with Raman Spectroscopy

Ilenia Severi, Marco Fosca, Georgia Colleluori, Federico Marini, Luca Imperatori, Martina Senzacqua, Angelica Di Vincenzo, Giorgio Barbatelli, Fabrizio Fiori, Julietta V. Rau, Antonio Giordano
2021 International Journal of Molecular Sciences  
Hypothalamic dysfunction is an initial event following diet-induced obesity, primarily involving areas regulating energy balance such as arcuate nucleus (Arc) and median eminence (ME). To gain insights into the early hypothalamic diet-induced alterations, adult CD1 mice fed a high-fat diet (HFD) for 6 weeks were studied and compared with normo-fed controls. Transmission and scanning electron microscopy and histological staining were employed for morphological studies of the ME, while Raman
more » ... E, while Raman spectroscopy was applied for the biochemical analysis of the Arc-ME complex. In HFD mice, ME β2-tanycytes, glial cells dedicated to blood-liquor crosstalk, exhibited remarkable ultrastructural anomalies, including altered alignment, reduced junctions, degenerating organelles, and higher content of lipid droplets, lysosomes, and autophagosomes. Degenerating tanycytes also displayed an electron transparent cytoplasm filled with numerous vesicles, and they were surrounded by dilated extracellular spaces extending up to the subependymal layer. Consistently, Raman spectroscopy analysis of the Arc-ME complex revealed higher glycogen, collagen, and lipid bands in HFD mice compared with controls, and there was also a higher band corresponding to the cyanide group in the former compared to the last. Collectively, these data show that ME β2-tanycytes exhibit early structural and chemical alterations due to HFD and reveal for the first-time hypothalamic cyanide presence following high dietary lipids consumption, which is a novel aspect with potential implications in the field of obesity.
doi:10.3390/ijms22158049 pmid:34360816 pmcid:PMC8347199 fatcat:dn7jsro3mzfz3mhwkzwqss3you
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