Evaluation of silicone based products used in the past as today for the consolidation of Venetian monumental stone surfaces

The commercial consolidating siloxane compounds EAS 40, Rhodorsil Consolidante RC90 and RC80, and the silicone water repellent agents Rhodorsil H224 and Hydrophase were carefully applied to stone specimens and tested to ascertain their chemical nature and their stability under oxidative stress and degradative environments. The resins were applied to laboratory samples (Carrara marble and Vicenza white limestone specimens) and subjected to controlled natural weathering and artificial ageing. The film morphology and the penetration depth was observed and measured by SEM-EDS determinations, while the stability of the resins was monitored by FTIR, SEM-EDX, colorimetric measurements and sponge tests. The results were compared with those obtained from a spread sampling of Venetian surfaces treated in the second half of the XX c. with Sogesil XR893 and X54-802, silicone resins which are no longer on the market. The overall results prompted a number of considerations on the effects of the resins applied to stone materials and offered the authors the opportunity to make a practical contribution to current practices in the consolidation of stone materials

The (Building) Stones of Venice under Threat: A Study about Their Deterioration between Climate Change and Land Subsidence

Cultural heritage assets face significant threats from climate change and land subsidence, leading to extensive social, economic, and environmental losses, and damage to artistic and monumental heritage in Italian coastal cities. In particular, addressing these challenges in the Venetian context necessitates the development of an adaptation plan for the lagoon area and the identificat on of targeted intervention strategies to preserve cultural and territorial heritage. To address these objectives, a systematic study was conducted to investigate the deterioration patterns exhibited by the most representative lithologies used in Venetian buildings. Thirty samples of five carbonate stone varieties subjected to natural aging were monitored in six different areas of Venice’s historic center and on Torcello Island, selected based on altimetry relative to tidal zero and exposure to environmental forces. An integrated multi-analytical approach was employed to identify and map macro- and micro-morphologies of stone surfaces related to chemical weathering and physical decay. Stones underwent evaluation during nine monitoring periods using various tests (ultrasound P-wave velocity and colorimetric measures) and analyses (μX-Ray Fluorescence, X-ray powder diffraction, stereomicroscope observations, and recognition of biological patinas). Data processing aimed to elucidate how microclimate and intrinsic stone features influence the occurrence and progression of deterioration phenomena. From the experimental findings, a Stone Deterioration Index and Intervention Procedures (SDIi) were proposed to estimate deterioration rates and assess the need for targeted intervention through conservative actions

Original or post-war paintings? The fixed wooden scenery of the Teatro Olimpico in Vicenza: a guided multidisciplinary approach based on scientific analyses and HBIM

Archival resources, a photogrammetric survey, analysis of materials and techniques, and evaluation of the state of conservation were interconnected phases in the interdisciplinary research on the perspective scenery of the Teatro Olimpico in Vicenza. To fill existing gaps related to the history of this unique artefact and to the undocumented retouching of paint layers on the scenery during post-war reconstruction work, a broad analytical approach (optical microscopy, XRPD, SEM–EDX, μFTIR and μRaman) was applied to micro-samples, the selection of which was guided by consolidated geometrical and archival data. The aims were to obtain a characterisation of the pigments and binders and to evaluate the microstratigraphic sequence, the state of conservation of the scenery flats, and the deterioration processes involved. The findings unveiled a discernible variability in the production techniques of the finishes, frequently lacking the classic microstratigraphic sequence associated with the traditional method for painting on wooden panels from the sixteenth century. Moreover, by identifying many pigments that could be used as temporal markers we were able unequivocally to establish, for the first time, that a significant part of the scenery designed by the architect Vincenzo Scamozzi was heavily repainted in the post-WWII period. These analytical results and all the data collected on the artefacts over time were related through an HBIM model, enabling the historical and technical- analytical information to be linked to the geometrical survey and thus to provide guidance for actions based on current and future knowledge for the maintenance and monitoring of the Teatro Olimpico

Durable control of psoriatic arthritis with guselkumab across domains and patient characteristics: post hoc analysis of a phase 3 study

Objectives: Evaluate patterns of stringent disease control with 2 years of guselkumab across key disease-identified domains and patient-reported outcomes (PROs) in subgroups of patients with psoriatic arthritis (PsA) defined by baseline characteristics. Method: This post hoc analysis of DISCOVER-2 (Clinicaltrials.gov NCT03158285) evaluated biologic-naïve PsA patients (≥ 5 swollen/ ≥ 5 tender joints, C-reactive protein [CRP] ≥ 0.6 mg/dL) randomized to guselkumab every 4 weeks (Q4W); guselkumab at Weeks 0 and 4, then Q8W; or placebo with crossover to guselkumab Q4W at Week 24. Achievement of American College of Rheumatology 50/70% improvement (ACR50/70), Investigator’s Global Assessment (IGA) 0, dactylitis/enthesitis resolution, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue response (≥ 4-point improvement), HAQ-Disability Index (HAQ-DI) response (≥ 0.35-point improvement), PsA Disease Activity Score (PASDAS) low disease activity (LDA), and minimal disease activity (MDA) was assessed at Weeks 24, 52, and 100 in subgroups defined by sex and baseline medication use, body mass index, PsA duration, swollen/tender joints, CRP, and psoriasis severity/extent. Patients with missing categorical response data were considered nonresponders. Results: 442/493 (90%) guselkumab-randomized patients completed treatment through Week 100. Significant multi-domain efficacy of guselkumab versus placebo was shown across adequately sized patient subgroups. A pattern of continuous improvement was observed across key PsA domains and PROs within patient subgroups: 65%–85% of guselkumab-randomized patients had enthesitis/dactylitis resolution, 50%–70% achieved complete skin clearance, 60%–80% reported meaningful improvements in function/fatigue, 40%–65% achieved PASDAS LDA, and 35%–50% achieved MDA at Week 100. Conclusion: Patients with active PsA receiving guselkumab demonstrated durable achievement of stringent endpoints associated with disease control across key PsA domains and PROs, regardless of baseline characteristics. Key Points • Among biologic-naïve patients with highly active psoriatic arthritis (PsA), efficacy of guselkumab across stringent disease endpoints and patient-reported outcomes (PROs) at Week 24 was consistent regardless of baseline demographics and disease characteristics. • Within guselkumab-randomized PsA patient subgroups, major improvements in joint disease activity, complete skin clearance, dactylitis/enthesitis resolution, clinically meaningful improvements in PROs, and achievement of low overall disease activity were maintained through Week 100. • Durable stringent endpoint achievement indicating disease control was observed with guselkumab, regardless of baseline patient or disease characteristics. Graphical Abstract

Characterization of Barium Hydroxide Used as Consolidating Agent for Monumental Surfaces in Venice

Barium hydroxide was one of the most widely used inorganic materials to consolidate calcareous stones during the 19th and 20th. The consolidation process occurs through a carbonation reaction. Several researchers studied the consolidation mechanism; however, the results are sometimes in conflict. More experimental work using modern analytical techniques and a multi-analytical approach is necessary to shed light on the mechanisms involved. This research aims to validate the chemical composition of the developed secondary products and to evaluate the treatment’s effectiveness over time. Carrara marble and Vicenza white limestone were treated and subjected to natural, artificial, and biological weathering. Furthermore, only a few microsamples were collected from Venetian historical artifacts treated in the 1960s and 1970s. Microscopic observations, sponge tests, FTIR, SEM-EDX, and microbiological analyses investigated the stability of the treatment over time and ascertained the chemical composition of the acicular crystals developed from the carbonation reaction of barium hydroxide. The results prompted a number of considerations useful for future restorations and for developing innovative compounds for consolidation interventions

Characterization of Barium Hydroxide Used as Consolidating Agent for Monumental Surfaces in Venice

Barium hydroxide was one of the most widely used inorganic materials to consolidate calcareous stones during the 19th and 20th. The consolidation process occurs through a carbonation reaction. Several researchers studied the consolidation mechanism; however, the results are sometimes in conflict. More experimental work using modern analytical techniques and a multi-analytical approach is necessary to shed light on the mechanisms involved. This research aims to validate the chemical composition of the developed secondary products and to evaluate the treatment’s effectiveness over time. Carrara marble and Vicenza white limestone were treated and subjected to natural, artificial, and biological weathering. Furthermore, only a few microsamples were collected from Venetian historical artifacts treated in the 1960s and 1970s. Microscopic observations, sponge tests, FTIR, SEM-EDX, and microbiological analyses investigated the stability of the treatment over time and ascertained the chemical composition of the acicular crystals developed from the carbonation reaction of barium hydroxide. The results prompted a number of considerations useful for future restorations and for developing innovative compounds for consolidation interventions

Caratterizzazione chimico-fisica di mattoni gotici veneziani

The aim of this experimental work was determine the characteristic features of Venetian Gothic bricks, in order to create an initial database for the city of Venice, and improve our knowledge of this class of materials, for the conservation of the walls of Gothic buildings and the dating of architectural surfaces. The study was extended to bricks found in dated archaeological sites of the town and of the Venetian lagoon. A total of 34 samples was subjected to mineralogical-petrographic, chemical and physical analysis (oM, XRD, SEM + EDS, XRF, MI) to get a initial overview about these Venetian bricks. The results identified some groups of samples sharing the same source materials and, probabily, also the same manufacturing technology. The study showed that this grouping does not depend on the origin of the bricks, rather on their dating, as di-mostrated by comparison with data related to more ancient Venetian bricks