Italian multicentre study on microbial environmental contamination in dental clinics: a pilot study

The dental practice is associated with a high risk of infections, both for patients and healthcare operators, and the environment may play an important role in the transmission of infectious diseases. A microbiological environmental investigation was carried out in six dental clinics as a pilot study for a larger multicentre study that will be performed by the Italian SItI (Society of Hygiene, Preventive Medicine and Public Health) working group "Hygiene in Dentistry". Microbial contamination of water, air and surfaces was assessed in each clinic during the five working days of the week, before and during treatments. Air and surfaces were also examined at the end of the daily activity. A wide variation was found in microbial environmental contamination, both within the participating clinics and relative to the different sampling times. Microbial water contamination in Dental Unit Water Systems (DUWS) reached values of up to 26 × 10⁴ cfu/mL (colony forming units per millilitre). P. aeruginosa was found in 33% of the sampled DUWS and Legionella spp. in 50%. A significant decrease in the Total Viable Count (TVC) was recorded during the activity. Microbial air contamination showed the highest levels during dental treatments and tended to decrease at the end of the working activity (p < 0.05). Microbial buildup on surfaces increased significantly during the working hours. As these findings point out, research on microbial environmental contamination and the related risk factors in dental clinics should be expanded and should also be based on larger collections of data, in order to provide the essential knowledge aimed at targeted preventive interventions.     

Non-Catalyzed and Pt/γ-Al2O3 Catalyzed Hydrothermal Cellulose Dissolution-Conversion: Influence of the Reaction Parameters

The dissolution of cellulose under 5 MPa of H₂ in the absence of catalyst is temperature and time dependant. The presence of Pt/γ-Al₂O₃ increases the initial rate of dissolution. The presence of H₂/Pt is essential although its exact role has not been well elucidated.     

Lipid and protein deterioration during the chilled storage of minced sea salmon (Pseudopercis semifasciata)

Sea salmon is a very appreciated seafood. The aim of this work was to analyze changes in lipid and protein fractions of minced muscle during chilled storage (1 ± 1 °C). Lipid oxidation was important during the first 6 days of storage according to 2‐thiobarbituric acid (TBA) values determined, decreasing mainly ω3 22:6 fatty acid content. Lipid hydrolysis was evident after 9 days of storage. Interaction compounds between oxidation products and other cellular components were analyzed by fluorescence measurements. The results obtained showed evidence of the formation of interaction products involved, mainly polar components such as proteins. Decreases in myosin and actin thermal stability and myosin denaturation were recorded by differential scanning calorimetry. Solubility of total and myofibrillar proteins decreased after 6 days of storage. The electrophoretic profile of soluble fractions showed an increase in the intensity of bands corresponding to low‐molecular‐weight polypeptides and a decrease in high‐molecular‐weight species. Available lysine content did not change during chilled storage. Copyright © 2007 Society of Chemical Industry     

Effect of kaolin and copper based products and of starter cultures on green table olive fermentation

In the present study table olives treated in field with kaolin and copper based products against “olive-fruit fly” were fermented using two selected strains of lactic acid bacteria (LAB). The fermentation process was monitored up to 260 days from brining through physico-chemical, microbiological and sensorial analyses. Results showed a dominance of LAB and yeasts and low level of Enterobacteriaceae counts throughout the whole process both in un-treated and treated samples. When investigating the effect of the single treatments on microbial dynamics, ANOVA results highlighted that copper based products affected significantly the control sample, while the sample inoculated with LAB starters maintained high level throughout the process, guaranteeing the fermentation process. Different behavior was revealed by yeasts population, which was partially influenced by copper treatment at the beginning of the fermentation.The polyphasic approach used in the present study, which combined sensory evaluation to microbial counts and physico-chemical characteristics, let to the conclusion on the importance of starter cultures in fermentation of table olives especially those treated with “non-conventional” pesticide, which could be used to prevent olive fly damage.     

SCIDDICA-SS3: a new version of cellular automata model for simulating fast moving landslides

Cellular Automata (CA) are discrete and parallel computational models useful for simulating dynamic systems that evolve on the basis on local interactions. Some natural events, such as some types of landslides, fall into this type of phenomena and lend themselves well to be simulated with this approach. This paper describes the latest version of the SCIDDICA CA family models, specifically developed to simulate debris-flows type landslides. The latest model of the family, named SCIDDICA-SS₃, inherits all the features of its predecessor, SCIDDICA-SS₂, with the addition of a particular strategy to manage momentum. The introduction of the latter permits a better approximation of inertial effects that characterize some rapid debris flows. First simulations attempts of real landslides with SCIDDICA-SS₃ have produced quite satisfactory results, comparable with the previous model.     

Kinetics of the Syntheses of Mesityl Oxide (MO) and Methyl Isobutyl Ketone (MIBK) in a Fixed-Bed Flow Reactor (FBR)

Nb₂O₅/SiO₂ and Pd/Nb₂O₅/SiO₂ catalysts were studied for the liquid phase syntheses of mesityl oxide (MO) and methyl isobutyl ketone (MIBK) in a fixed bed flow reactor (FBR). Catalyst activities as high as 1.7 g/h g_cat and selectivities ranging from 93.4 to 100% for MO synthesis were observed. The catalyst activity was found to be a strong function of space velocity likely due to product inhibition. A synergistic effect was observed whereby the catalyst activity for all organic products increased by 22% and the MIBK productivity increased by 20% at 160 °C and WHSV = 8.6 h^?1 from the introduction of hydrogen to the reactor. However, the MIBK selectivity was constrained to less than 83.5% due to competing reactions.     

D2S: Document-to-sentence framework for novelty detection

Novelty detection aims at identifying novel information from an incoming stream of documents. In this paper, we propose a new framework for document-level novelty detection using document-to-sentence (D2S) annotations and discuss the applicability of this method. D2S first segments a document into sentences, determines the novelty of each sentence, then computes the document-level novelty score based on a fixed threshold. Experimental results on APWSJ data show that D2S outperforms standard document-level novelty detection in terms of redundancy-precision (RP) and redundancy-recall (RR). We applied D2S on the document-level data from the TREC 2004 and TREC 2003 Novelty Track and find that D2S is useful in detecting novel information in data with a high percentage of novel documents. However, D2S shows a strong capability to detect redundant information regardless of the percentage of novel documents. D2S has been successfully integrated in a real-world novelty detection system.     

Effect of the nitrogen heterocyclic compounds on hydrodesulfurization using in situ hydrogen and a dispersed Mo catalyst

The hydrodesulfurization (HDS) of the highly refractory sulfur-containing compounds, dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT), and the effect of the basic and non-basic nitrogen heterocyclic compounds, such as quinoline and carbazole, on HDS using a dispersed unsupported Mo catalyst and in situ generated hydrogen were studied. Experimental results indicated that the dispersed unsupported Mo catalyst was effective for the HDS of 4,6-DMDBT in a mixture containing DBT. The direct desulfurization pathway (DDS) was the preferred pathway for the HDS of DBT while the hydrogenation pathway (HYD) was the preferred pathway for the HDS of 4,6-DMDBT under our experimental conditions. A strong inhibitive effect of the basic quinoline or the non-basic carbazole on the HDS of each of the sulfur-containing compounds was observed. The DDS and HYD pathways in the HDS of the refractory sulfur-containing compounds were affected to a different extent by the nitrogen-containing compounds, suggesting that different active sites were involved in these two reaction pathways.     

Polyhydrosilane Mediated Synthesis of One-Dimensional Gold Nanostructures

This work presents a solution-phase approach for the “one pot” synthesis of polysilane-gold nanorods. The process starts by the reduction of HAuCl₄ to Au^o with a solution of poly[diphenylsilane-co-methyl(H)silane] cooled to 4 °C. The formed small Au nanoparticles (5–15 nm diameter) serve further as seeds for the heterogeneous nucleation and anisotropic growth that takes place at 25 °C and yields crystalline needle-like polymer–gold nanostructures. The evolution of the small spherical nanoparticles to nanorods with length/width aspect ratios up to 10³ has been proved by UV–Vis spectroscopy, polarized light microscopy and AFM. Further insights on the growth mechanism were obtained by SEM, DLS and TEM.