Spectroscopic assessment of the UV laser removal of varnishes on paint substrates

TECHNART 2015 − Catania, April 27 - 30, 2015; http://technart2015.lns.infn.it/The removal/thinning of aged varnishes from easel paintings is a very complex issue, which involves the need of finely-optimized conservation treatments for preserving both the pictorial substrates and the remaining varnish film. To this goal, cleaning techniques based on laser ablation may satisfy these requirements, especially when wavelengths and pulse durations are accurately selected. Recently, with the aim of minimizing photo-thermal, photo-mechanical and photo-chemical phenomena, ultra-short lasers operating in picosecond and femtosecond regimes have been introduced in the field [1-2]. Processing of fresh mastic and dammar varnishes with 248 nm, 500 fs laser pulses results in an improved etched morphology as compared with ns pulses of the same wavelength [1]. Irradiation of shellac at 213 nm with pulses of 15 ns of photo-sensitive tempera paint models covered with shellac allows controlled micrometric removal without affecting the surface morphology and chemical composition of the remaining varnish film and underlying paint layers. However, fs multiple pulse Ti:Sapphire irradiation of films of this varnish at 795, 398 and 265 nm has turned out to be ineffective for removing shellac varnish from egg-yolk based tempera paints [2]. Taking advantage from the latest findings, in the present work we focus on the assessment of the chemical and physical modifications induced by laser irradiation of varnish samples (i.e. dammar, mastic, shellac, mastic-oil) after natural and artificial ageing by using confocal ¿-Raman and laser induced fluorescence spectroscopies. We irradiated the varnish films with the fifth (213 nm) and fourth (266 nm) harmonics of a pulsed nanosecond (15 ns) Q-switched Nd:YAG laser. Together with systematic microscopy inspection of the irradiated areas, a significant effort was devoted to the study of the optical properties of the varnish films by means of UV-Vis absorption spectroscopy, which allowed the determination of linear absorption coefficients at the laser irradiation wavelengths used. Single-pulse laser ablation thresholds were measured by applying the spot regression method and processing of the films was carried out using three different scanning speeds that resulted in 1, 5 and 10 laser pulses on each irradiated area. The obtained results, using fluences well above the single-pulse ablation threshold of the treated varnishes, depend crucially on the irradiation wavelength, the considered varnish and its degree of polymerization. In contrast with the induced modifications resulting from irradiation at 266 nm, that lead to a whitish appearance (indicative of bubble formation) and discoloration of pigments, the promising results achieved at 213 nm emphasize the importance of using a highly absorbed wavelength to finely remove the oxidized uppermost layer of different types of aged varnishes. [1] Pouli, P., Paun, I. A., Bounos, G., Georgiou, S., Fotakis, C., Applied Surface Science, 254(21), 2008, 6875-6879. [2] Oujja, M., García, A., Romero, C., de Aldana, J. R. V., Moreno, P., Castillejo, M., Physical Chemistry Chemical Physics, 13(10), 2011, 4625-4631.Peer Reviewe

Tumor-Associated Macrophages in Multiple Myeloma: Key Role in Disease Biology and Potential Therapeutic Implications

Multiple myeloma (MM) is characterized by multiple relapse and, despite the introduction of novel therapies, the disease becomes ultimately drug-resistant. The tumor microenvironment (TME) within the bone marrow niche includes dendritic cells, T-cytotoxic, T-helper, reactive B-lymphoid cells and macrophages, with a complex cross-talk between these cells and the MM tumor cells. Tumor-associated macrophages (TAM) have an important role in the MM pathogenesis, since they could promote plasma cells proliferation and angiogenesis, further supporting MM immune evasion and progression. TAM are polarized towards M1 (classically activated, antitumor activity) and M2 (alternatively activated, pro-tumor activity) subtypes. Many studies demonstrated a correlation between TAM, disease progression, drug-resistance and reduced survival in lymphoproliferative neoplasms, including MM. MM plasma cells in vitro could favor an M2 TAM polarization. Moreover, a possible correlation between the pro-tumor effect of M2 TAM and a reduced sensitivity to proteasome inhibitors and immunomodulatory drugs was hypothesized. Several clinical studies confirmed CD68/CD163 double-positive M2 TAM were associated with increased microvessel density, chemoresistance and reduced survival, independently of the MM stage. This review provided an overview of the biology and clinical relevance of TAM in MM, as well as a comprehensive evaluation of a potential TAM-targeted immunotherapy

High efficiency, diode pumped 170 W Nd:YAG ceramic slab laser

A new thin-slab ceramic Nd:YAG laser is presented based on a novel zig-zag configuration. The slab is shaped in such a way that the beam propagates internally bouncing on the thin lateral faces (Edge zig-zag). Preliminary experiments have demonstrated a power extraction of 170 W (CW) at an optical conversion efficiency of 36%. Measurements have also been performed to assess the propagation properties, at least in the thinner transverse direction, of the beam extracted with a simple stable resonator. This laser format appears as a good competitor of the more traditional face-pumped or edge-pumped zig-zag slab laser schemes

Experimental study of the delayed threshold phenomenon in a semiconductor laser

An experimental study of the delayed threshold phenomenon in a Vertical Extended Cavity Semiconductor Emitting Laser is carried out. Under modulation of the pump power, the laser intensity exhibits a hysteresis behavior in the vicinity of the threshold. The temporal width of this hysteresis is measured as a function of the modulation frequency, and is proved to follow the predicted scaling law. A model based on the rate equations is derived and used to analyze the experimental observations. A frequency variation of the laser around the delayed threshold and induced by the phase-amplitude coupling is predicted and estimated

Drug resistance and minimal residual disease in multiple myeloma

Great progress has been made in improving survival in multiple myeloma (MM) patients over the last 30 years. New drugs have been introduced and complete responses are frequently seen. However, the majority of MM patients do experience a relapse at a variable time after treatment, and ultimately the disease becomes drug-resistant following therapies. Recently, minimal residual disease (MRD) detection has been introduced in clinical trials utilizing novel therapeutic agents to measure the depth of response. MRD can be considered as a surrogate for both progression-free and overall survival. In this perspective, the persistence of a residual therapy-resistant myeloma plasma cell clone can be associated with inferior survivals. The present review gives an overview of drug resistance in MM, i.e., mutation of β5 subunit of the proteasome; upregulation of pumps of efflux; heat shock protein induction for proteasome inhibitors; downregulation of CRBN expression; deregulation of IRF4 expression; mutation of CRBN, IKZF1, and IKZF3 for immunomodulatory drugs and decreased target expression; complement protein increase; sBCMA increase; and BCMA down expression for monoclonal antibodies. Multicolor flow cytometry, or next-generation flow, and next-generation sequencing are currently the techniques available to measure MRD with sensitivity at 10-5. Sustained MRD negativity is related to prolonged survival, and it is evaluated in all recent clinical trials as a surrogate of drug efficacy

A Study on the Efficiency of Sustainable Wine Grape Vineyard Management Strategies

Crop protection strategies based on cupric products and mainly adopted in organic viticulture produce a consistent environmental impact due to the persistence of copper in soils and its negative effects on edaphic biodiversity. In this work, trials were carried out during the crop years 2018–2020 in a vineyard with an organic management by a low-copper strategy and in a conventional IPM management with an IPM strategy with reduced use of fungicides. Phytosanitary treatments have been strictly planned according to forecasting models, and fungicides have been partially substituted with substances improving the resistance mechanisms of plants. Different strategies of green manure management, in order to improve the health of vines, were also adopted. Results suggest the efficacy of the “GreenGrapes” plant protection strategy in conditions of low downy mildew pressure. Furthermore, no declines in the production quality have been recorded; conversely, the synergic effect of the green manure and the tested biostimulant substances (“GreenGrapes” protocols) and the green manure management improved yield and grape quality, compared with conventional conduction (IPM and Organic) with a grass covering

Evaluation of analytical performance and comparison of clinical results of the new generation method AccuTnI+3 for the measurement of cardiac troponin I using both patients and quality control plasma samples

The study aims are to evaluate the analytical performance and the clinical results of the chemiluminescent Access AccuTnI+3 immunoassay for the determination of cardiac troponin I (cTnI)with DxI 800 and Access2 platforms and to compare the clinical results obtained with this method with those of three cTnI immunoassays, recently introduced in the European market. The limits of blank (LoB), detection (LoD), and quantitation (LoQ) at 20% CV and 10% CV were 4.5 ng/L and 10.9 ng/L, 17.1 and 30.4 ng/L, respectively. The results of STAT Architect high Sensitive TnI (Abbott Diagnostics), ADVIA Centaur Troponin I Ultra (Siemens Healthcare Diagnostics), ST AIA-Pack cTnI third generation (Tosoh Bioscience), and Access AccuTnI + 3 (Beckman Coulter Diagnostics) showed very close correlations (R ranging from 0.901 to 0.994) in 122 samples of patients admitted to the emergency department. However, on average there was a difference up to 2.4-fold between the method measuring the highest (ADVIA method) and lowest cTnI values (AccuTnI + 3 method). The consensus mean values between methods ranged from 6.2% to 29.6% in 18 quality control samples distributed in an external quality control study (cTnI concentrations ranging from 29.3 ng/L to 1557.5 ng/L). In conclusion, the results of our analytical evaluation concerning the AccuTnI + 3 method, using the DxI platform, are well in agreement with those suggested by the manufacturer as well as those reported by some recent studies using the Access2 platform. Our results confirm that the AccuTnI + 3 method for the Access2 and DxI 800 platforms is a clinically usable method for cTnI measurement

Delayed Self-Synchronization in Homoclinic Chaos

The chaotic spike train of a homoclinic dynamical system is self-synchronized by re-inserting a small fraction of the delayed output. Due to the sensitive nature of the homoclinic chaos to external perturbations, stabilization of very long periodic orbits is possible. On these orbits, the dynamics appears chaotic over a finite time, but then it repeats with a recurrence time that is slightly longer than the delay time. The effect, called delayed self-synchronization (DSS), displays analogies with neurodynamic events which occur in the build-up of long term memories.Comment: Submitted to Phys. Rev. Lett., 13 pages, 7 figure

Fludarabine, high-dose cytarabine and idarubicin-based induction may overcome the negative prognostic impact of flt3-itd in npm1 mutated aml, irrespectively of flt3-itd allelic Burden

The mutations of NPM1 and FLT3-ITD represent the most frequent genetic aberration in acute myeloid leukemia. Indeed, the presence of an NPM1 mutation reduces the negative prognostic impact of FLT3-ITD in patients treated with conventional “3+7” induction. However, little information is available on their prognostic role with intensified regimens. Here, we investigated the efficacy of a fludarabine, high-dose cytarabine and idarubicin induction (FLAI) in 149 consecutive fit AML patients (median age 52) carrying the NPM1 and/or FLT3-ITD mutation, treated from 2008 to 2018. One-hundred-and-twenty-nine patients achieved CR (86.6%). After a median follow up of 68 months, 3-year overall survival was 58.6%. Multivariate analysis disclosed that both NPM1mut (p < 0.05) and ELN 2017 risk score (p < 0.05) were significant predictors of survival. NPM1-mutated patients had a favorable outcome, with no significant differences between patients with or without concomitant FLT3-ITD (p = 0.372), irrespective of FLT3-ITD allelic burden. Moreover, in landmark analysis, performing allogeneic transplantation (HSCT) in first CR proved to be beneficial only in ELN 2017 high-risk patients. Our data indicate that FLAI exerts a strong anti-leukemic effect in younger AML patients with NPM1mut and question the role of HSCT in 1st CR in NPM1mut patients with concomitant FLT3-ITD