Mythical numbers and the proceeds of organised crime: estimating mafia proceeds in Italy

Organised crime is a field vulnerable to mythical numbers, i.e. exaggerated estimates lacking empirical support, but acquiring acceptance through repetition. The figures on mafia proceeds in Italy are a striking example of this problem. This study proposes an estimation of mafia proceeds in Italy from nine criminal activities (sexual exploitation of women, illicit firearms trafficking, drug trafficking, counterfeiting, the illicit cigarette trade, illicit gambling, illicit waste disposal, loan sharking, and extortion racketeering) by region and type of mafia (Cosa Nostra, Camorra,\u2018Ndrangheta, Apulian mafias, and other mafias). The results estimate yearly mafia proceeds at approximately \u20ac10.7 bn (0.7% of the Italian GDP), discussing the impact on the regional and national economies and the differences among the types of mafias as to their geographical sources of revenue

Atomic resolution insight into host cell recognition by Toxoplasma gondii.

Accepted versio

Expanding applications of SERS through versatile nanomaterials engineering

Surface-enhanced Raman scattering (SERS) spectroscopy has evolved into a cross-disciplinary analytical technique by unveiling relevant chemical, biological, material, and structural information. The focus of this review is on two critical properties for successfully expanding applications of SERS spectroscopy: quality of the plasmonic substrate and molecule localization to the substrate. In this review, we discuss recent work on quantifying SERS distance dependence, key factors for substrate characterization and performance evaluation, expansion of SERS applications through substrate development for UV plasmonics and short-distance capture strategies for optimizing analyte-surface structures. After surveying the recent developments of these seemingly disparate fields, we suggest new research directions that may originate from a synergistic blend of all the herein discussed topics. Finally, we discuss major challenges and open questions related to the application of SERS for understanding of chemical processes at the nanoscale, with special interest on in situ catalysts and biosensing.Fil: Cardinal, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Northwestern University; Estados UnidosFil: Vander Ende, Emma. Northwestern University; Estados UnidosFil: Hackler, Ryan A.. Northwestern University; Estados UnidosFil: McAnally, Michael O.. Northwestern University; Estados UnidosFil: Stair, Peter C.. Northwestern University; Estados UnidosFil: Schatz, George C.. Northwestern University; Estados UnidosFil: Van Duyne, Richard P.. Northwestern University; Estados Unido

Nucleation and Growth of Silver Nanoparticles by AB and ABC-Type Atomic Layer Deposition

In this work, we report synthesis strategies to produce Ag nanoparticles by AB-type and ABC-type atomic layer deposition (ALD) using trimethylphosphine­(hexafluoroacetylacetonato) silver­(I) ((hfac)­Ag­(PMe₃)) and formalin (AB-type) and (hfac)­Ag­(PMe₃), trimethylaluminum, and H₂O (ABC-type). In situ quartz crystal microbalance measurements reveal a Ag growth rate of 1–2 ng/cm²/cycle by ABC-type ALD at 110 °C and 2–10 ng/cm²/cycle for AB-type ALD at 170–200 °C. AB-type Ag ALD has a nucleation period before continuous linear growth that is shorter at 200 °C. Transmission electron microscopy reveals that AB-type Ag ALD particles have an average size of ∼1.8 nm after 10 cycles. ABC-type Ag ALD particles have an average size of ∼2.2 nm after 20 cycles. With increasing ALD cycles, ABC-type Ag ALD increases the metal loading while maintaining the particle size but AB-type Ag ALD results in the formation of bigger particles in addition to small particles. The ability to synthesize supported metal nanoparticles with well-defined particle sizes and narrow size distributions makes ALD an attractive synthesis method compared to conventional wet chemistry techniques

Identification of Dimeric Methylalumina Surface Species during Atomic Layer Deposition Using <i>Operando</i> Surface-Enhanced Raman Spectroscopy

<i>Operando</i> surface-enhanced Raman spectroscopy (SERS) was used to successfully identify hitherto unknown dimeric methylalumina surface species during atomic layer deposition (ALD) on a silver surface. Vibrational modes associated with the bridging moieties of both trimethylaluminum (TMA) and dimethylaluminum chloride (DMACl) surface species were found during ALD. The appropriate monomer vibrational modes were found to be absent as a result of the selective nature of SERS. Density functional theory (DFT) calculations were also performed to locate and identify the expected vibrational modes. An <i>operando</i> localized surface plasmon resonance (LSPR) spectrometer was utilized to account for changes in SER signal as a function of the number of ALD cycles. DMACl surface species were unable to be measured after multiple ALD cycles as a result of a loss in SERS enhancement and shift in LSPR. This work highlights how <i>operando</i> optical spectroscopy by SERS and LSPR scattering are useful for probing the identity and structure of the surface species involved in ALD and, ultimately, catalytic reactions on these support materials

Probing the Chemistry of Alumina Atomic Layer Deposition Using <i>Operando</i> Surface-Enhanced Raman Spectroscopy

This work demonstrates for the first time the capability of measuring surface vibrational spectra for adsorbates during atomic layer deposition (ALD) reactions using <i>operando</i> surface-enhanced Raman spectroscopy (SERS). We use SERS to study alumina ALD growth at 55 °C on bare silver film-over nanosphere (AgFON) substrates as well as AgFONs functionalized with thiol self-assembled monolayers (SAMs). On bare AgFONs, we observe the growth of Al–C stretches, symmetric C–H and asymmetric C–H stretches during the trimethylaluminum (TMA) dose half-cycle, and their subsequent decay after dosing with H₂O. Al–C and C–H vibrational modes decay in intensity with time even without H₂O exposure providing evidence that residual H₂O in the ALD chamber reacts with −CH₃ groups on AgFONs. The observed Al–C stretches are attributed to TMA dimeric species on the AgFON surface in agreement with density functional theory (DFT) studies. We observe Al–C stretches and no thiol vibrational frequency shifts after dosing TMA on AgFONs functionalized with toluenethiol and benzenethiol SAMs. Conversely, we observe thiol vibrational frequency shifts and no Al–C stretches for AgFONs functionalized with 4-mercaptobenzoic acid and 4-mercaptophenol SAMs. Lack of observed Al–C stretches for COOH- and OH-terminated SAMs is explained by the spacing of Al–(CH₃)_<i>x</i> groups from the SERS substrate. TMA penetrates through SAMs and reacts directly with Ag for benzenethiol and toluenethiol SAMs and selectively reacts with the −COOH and −OH groups for 4-mercaptobenzoic acid and 4-mercaptophenol SAMs, respectively. The high sensitivity and chemical specificity of SERS provides valuable information about the location of ALD deposits with respect to the enhancing substrate. This information can be used to evaluate the efficacy of SAMs in blocking or allowing ALD deposition on metal surfaces. The ability to probe ALD reactions using SERS under realistic reaction conditions will lead to a better understanding of the mechanisms of ALD reactions

High-Resolution Distance Dependence Study of Surface-Enhanced Raman Scattering Enabled by Atomic Layer Deposition

We present a high-resolution distance dependence study of surface-enhanced Raman scattering (SERS) enabled by atomic layer deposition (ALD) at 55 and 100 °C. ALD is used to deposit monolayers of Al₂O₃ on bare silver film over nanospheres (AgFONs) and AgFONs functionalized with self-assembled monolayers. <i>Operando</i> SERS is used to measure the intensities of the Al–CH₃ and C–H stretches from trimethylaluminum (TMA) as a function of distance from the AgFON surface. This study clearly demonstrates that SERS on AgFON substrates displays both a short- and long-range nanometer scale distance dependence. Excellent agreement is obtained between these experiments and theory that incorporates both short-range and long-range terms. This is a high-resolution <i>operando</i> SERS distance dependence study performed in one integrated experiment using ALD Al₂O₃ as the spacer layer and Raman label simultaneously. The long-range SERS distance dependence should make it possible to detect chemisorbed surface species located as far as ∼3 nm from the AgFON substrate and will provide new insight into the surface chemistry of ALD and catalytic reactions