Can we infer the presence of Differential Privacy in Deep Learning models' weights? Towards more secure Deep Learning

Differential Privacy (DP) is a key property to protect data and models from integrity attacks. In the Deep Learning (DL) field, it is commonly implemented through the Differentially Private Stochastic Gradient Descent (DP-SGD). However, when a model is shared or released, there is no way to check whether it is differentially private, that is, it required to trust the model provider. This situation poses a problem when data privacy is mandatory, specially with current data regulations, as the presence of DP can not be certificated consistently by any third party. Thus, we face the challenge of determining whether a DL model has been trained with DP, according to the title question: Can we infer the presence of Differential Privacy in Deep Learning models' weights? Since the DP-SGD significantly changes the training process of a DL model, we hypothesize that DP leaves an imprint in the weights of a DL model, which can be used to predict whether a model has been trained with DP regardless of its architecture and the training dataset. In this paper, we propose to employ the imprint in model weights of using DP to infer the presence of DP training in a DL model. To substantiate our hypothesis, we developed an experimental methodology based on two datasets of weights of DL models, each with models with and without DP training and a meta-classifier to infer whether DP was used in the training process of a DL model, by accessing its weights. We accomplish both, the removal of the requirement of a trusted model provider and a strong foundation for this interesting line of research. Thus, our contribution is an additional layer of security on top of the strict private requirements of DP training in DL models, towards to DL models

Rhodium(I) complexes with hemilabile phosphines: Rational design for efficient oxidative amination catalysts

13 páginas, 10 figuras, 6 tablas, 4 esquemas.A series of cationic square-planar rhodium(I) complexes of type [Rh(cod){Ar2P(CH2)nZ}]+, [Rh(cod){Ar2P(CH2)nZ}2]+, and [Rh{Ar2P(CH2)nZ}2]+, which contained diverse functionalized hemilabile phosphine ligands of type Ar2P(CH2)nZ (n=1–3; Z=OMe, OEt, OnBu, NMe2, SMe), were synthesized and spectroscopically characterized. The crystal structures of representative compounds were determined by X-ray diffraction. Most complexes were active catalysts for the anti-Markovnikov oxidative amination of styrene with piperidine to produce (E)-1-styrylpiperidine. Catalyst screening showed a remarkable relationship between the hemilabile ligand, the precatalyst structure, and the catalytic activity. The more-efficient catalysts were those that had arylphosphine ligands with a 2-alkoxyethyl- or 3-alkoxypropyl hemilabile moiety, Ar2P(CH2)nOR (n=2, 3; R=Me, Et, nBu). This study has revealed the outstanding catalytic activity of bis-phosphine complexes [Rh{(4-R-C6H4)2P(CH2)3OEt}2][PF6] (R=H, Me, OMe), with unprecedented turnover frequencies of up to 80 h−1 (R=Me) and excellent enamine selectivity (96 %).Financial support from the Ministerio de Ciencia e Innovación (MICINN/FEDER): CTQ2010-15221, MULTICAT (CSD2009-00050), and Factoría de Cristalización (CSD2006-0015) is gratefully acknowledged. M.I.B. thanks the Spanish MICINN and the IUCH (Instituto Universitario de Catálisis Homogénea) for a predoctoral fellowship.Peer reviewe

Heavy metals removal from electroplating wastewater by aminopropyl-Si MCM-41

Abstract The potential of removing nickel and copper from industrial electroplating wastewaters by using mesoporous materials with MCM-41 type structure functionalised with different ratios of aminopropyl groups, namely Na 50 , Na 25 and Na 5 , were evaluated. The synthesised solids sorbents obtained were characterised by X-ray diffraction, elemental chemical analysis and IR spectroscopy. In preliminary experiments, studies were carried out to determine the optimal experimental conditions for the retention of heavy ions. Effects of concentration, optimal pH, interference with humic substances and other metals were studied for Na 5 , which showed the best capacity of absorption determined by the corresponding isotherm. This material has a greater selectivity against sodium, indicating that ionic strength does not affect the extraction. Results of an application of this material to remove nickel and copper in synthetic and real industrial wastewater samples from an electrochemical industry area are shown with successful results. The lowest level of nickel and copper were observed when Na 5 was used. This observation suggests that reactive aminopropyl-Si MCM-41 and similar materials may be a promising and provide for alternative environmental technologies in the future

Survey on Federated Learning Threats: concepts, taxonomy on attacks and defences, experimental study and challenges

Federated learning is a machine learning paradigm that emerges as a solution to the privacy-preservation demands in artificial intelligence. As machine learning, federated learning is threatened by adversarial attacks against the integrity of the learning model and the privacy of data via a distributed approach to tackle local and global learning. This weak point is exacerbated by the inaccessibility of data in federated learning, which makes harder the protection against adversarial attacks and evidences the need to furtherance the research on defence methods to make federated learning a real solution for safeguarding data privacy. In this paper, we present an extensive review of the threats of federated learning, as well as as their corresponding countermeasures, attacks versus defences. This survey provides a taxonomy of adversarial attacks and a taxonomy of defence methods that depict a general picture of this vulnerability of federated learning and how to overcome it. Likewise, we expound guidelines for selecting the most adequate defence method according to the category of the adversarial attack. Besides, we carry out an extensive experimental study from which we draw further conclusions about the behaviour of attacks and defences and the guidelines for selecting the most adequate defence method according to the category of the adversarial attack. This study is finished leading to meditated learned lessons and challenges

Hybrid chitosan derivative-carbon suport for oxygen reduction reactions

New hybrid chitosan derivative-carbon black was prepared and used as support for Pt nanoparticles. These catalysts improved the activity toward oxygen reduction reaction (ORR), compared with those of commercial Pt/C catalyst. The biopolymer chitosan provided an efficient and sustainable surface nitrogen source associated with the superior performance of the catalysts.Peer reviewe

Oxidation and β-alkylation of alcohols catalysed by Iridium(I) complexes with functionalised N-heterocyclic Carbene ligands

The borrowing hydrogen methodology allows for the use of alcohols as alkylating agents for C-C bond forming processes offering significant environmental benefits over traditional approaches. Iridium(I)-cyclooctadiene complexes having a NHC ligand with a O- or N-functionalised wingtip efficiently catalysed the oxidation and β-alkylation of secondary alcohols with primary alcohols in the presence of a base. The cationic complex [Ir(NCCH)(cod)(MeIm(2- methoxybenzyl))][BF] (cod=1,5-cyclooctadiene, MeIm=1-methylimidazolyl) having a rigid O-functionalised wingtip, shows the best catalyst performance in the dehydrogenation of benzyl alcohol in acetone, with an initial turnover frequency (TOF) of 1283 h, and also in the β-alkylation of 2-propanol with butan-1-ol, which gives a conversion of 94 % in 10 h with a selectivity of 99 % for heptan-2-ol. We have investigated the full reaction mechanism including the dehydrogenation, the cross-aldol condensation and the hydrogenation step by DFT calculations. Interestingly, these studies revealed the participation of the iridium catalyst in the key step leading to the formation of the new C-C bond that involves the reaction of an O-bound enolate generated in the basic medium with the electrophilic aldehyde.Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO/FEDER, Project CTQ2013-42532-P), MICINN (Project Consolider Ingenio 2010 CSD2009-00050) and Diputación General de Aragón (DGA/FSE-E07) is gratefully acknowledged. J.F.-T. thanks the Spanish MICINN for a predoctoral fellowship.Peer Reviewe

From the Eukaryotic Molybdenum Cofactor Biosynthesis to the Moonlighting Enzyme mARC

All eukaryotic molybdenum (Mo) enzymes contain in their active site a Mo Cofactor (Moco), which is formed by a tricyclic pyranopterin with a dithiolene chelating the Mo atom. Here, the eukaryotic Moco biosynthetic pathway and the eukaryotic Moco enzymes are overviewed, including nitrate reductase (NR), sulfite oxidase, xanthine oxidoreductase, aldehyde oxidase, and the last one discovered, the moonlighting enzyme mitochondrial Amidoxime Reducing Component (mARC). The mARC enzymes catalyze the reduction of hydroxylated compounds, mostly N-hydroxylated (NHC), but as well of nitrite to nitric oxide, a second messenger. mARC shows a broad spectrum of NHC as substrates, some are prodrugs containing an amidoxime structure, some are mutagens, such as 6-hydroxylaminepurine and some others, which most probably will be discovered soon. Interestingly, all known mARC need the reducing power supplied by different partners. For the NHC reduction, mARC uses cytochrome b5 and cytochrome b5 reductase, however for the nitrite reduction, plant mARC uses NR. Despite the functional importance of mARC enzymatic reactions, the structural mechanism of its Moco-mediated catalysis is starting to be revealed. We propose and compare the mARC catalytic mechanism of nitrite versus NHC reduction. By using the recently resolved structure of a prokaryotic MOSC enzyme, from the mARC protein family, we have modeled an in silico three-dimensional structure of a eukaryotic homologue

N-Methylation of Amines with Methanol Catalyzed by Iridium(I) Complexes Bearing an N, O-Functionalized NHC Ligand

A set of neutral IrBr(L-2)-(kappa C-(t)BuImCH(2)PyCH(2)OMe)] and cationic Ir(L-2)-(kappa C, N-tBuImCH(2)PyCH(2)OMe)]PF6 (L-2 = cod, (CO)(2)) Ir(I) compounds featuring a flexible lutidine-derived polydentate ligand having NHC and - OMe as donor functions have been evaluated as catalyst precursors for the N-methylation of aniline using methanol both as a reducing agent and a C1 source. The carbonyl complexes are somewhat more active than the related diene compounds with the neutral compound IrBr(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] being the more active. A range of aromatic primary amines, including heterocyclic amines, have been selectively transformed into the corresponding N-methylamino derivatives using this catalyst at a low catalyst loading (0.1 mol %) and substoichiometric amounts of Cs2CO3 (half equiv) as a base, in methanol at 423 K. For aliphatic primary amines, selective N, N-dimethylation was achieved under the same catalytic conditions. The unselective deprotonation of the methylene linkers in IrBr(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] affords two isomeric neutral complexes featuring a coordinated dearomatized pyridine core, which were converted into Ir(OMe)(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] upon addition of methanol. This compound undergoes thermal activation of a C-H bond of the tert-butyl group to give the cyclometalated iridium(I) complex Ir(CO)(2){kappa C-2, C-(-CH2Me2C-ImCH(2)PyCH(2)OMe)}] featuring a bidentate C, C-coordinated NHC ligand. Mechanistic investigations support a borrowing hydrogen mechanism proceeding through iridium(I) intermediates with the methoxo complex as the catalytic active species and the cyclometalated complex as the catalyst resting state. Deuterium labeling experiments have demonstrated that both species are in equilibrium under catalytic conditions, which is consistent with the exhibited catalytic activity of the cyclometalated complex

Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts

After pandemic, healthcare workers experienced a series of emotional and psychological disturbances that could impact their mental well-being. In this study, the feasibility of morphological characteristics of photoplethysmographic (PPG) waveform to quantify stress and depression level posed by COVID-19 in first-line healthcare workers is explored. Results show that higher stress and depression level are moderately correlated with large systolic amplitude and parameters that might indicate early wave reflection. These results suggest that an arterial stiffness, quantified with PPG morphological characteristics, could provide valuable information in assessing mental healt

Enhancing the hydrogen transfer catalytic activity of hybrid carbon nanotube-based NHC–iridium catalysts by increasing the oxidation degree of the nanosupport

CVD-grown multiwalled carbon nanotubes were purified by applying four different treatments with increasing oxidation severity. The growing severity of the treatment results in progressive oxygen functionalization of the surface along with introduction of an increasing quantity of defects on the carbon nanotube walls. Iridium–N-heterocyclic carbene complexes were covalently anchored to those oxidized surfaces through their surface carboxylic acids via acetyl linkers. The carbon nanotube-based iridium–NHC hybrid materials developed are active in the hydrogen-transfer reduction of cyclohexanone to cyclohexanol with 2-propanol/KOH as hydrogen source but with rather different activity. The catalytic activity of the hybrid catalysts is strongly influenced by the type and amount of oxygenated functionalization resulting from the treatment applied to the support, being the most active and the most oxidized material