74 research outputs found

    Electron-transfer-induced reductive dealkoxylation of alkyl aryl ethers. III. Reductive cleavage of methoxy-substituted <i>N</i>,<i>N</i>-dimethylanilines (<i>N</i>,<i>N</i>-dimethylanisidines)

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    The reactivity of the three isomeric methoxy-substituted N,N-dimethylanilines (N,N-dimethylanisidines) and of N,N-dimethyl-2,6-dimethoxyaniline in the reduction with alkali metals in aprotic solvents was investigated. N,N-Dimethyl-p-methoxyaniline was found to be unreactive, while the other substrates underwent exclusive cleavage of carbon-oxygen bond(s), with the following order of reactivity: 2,6-dimethoxy > o-methoxy > m-methoxy > p-methoxy. Both the relative reactivity and the regioselectivity of cleavage (demethoxylation vs. demethylation) was found to parallel closely that of the corresponding di- and trimethoxysubstituted substrates. These results suggest that intermediates with different electron distribution or even different intermediates are involved in the reductive cleavage of aryl-oxygen and arylnitrogen bonds

    A modular modelling approach to stochastic simulation of production – logistic systems

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    The economic scenario today is highly competitive in terms of costs and number of competitors, so it isnecessary to adopt strategies that allow the constant improvement of manufacturing processes withinthe spending constrains. Simulation models are useful to support and drive company management inimproving the performances of production and logistic systems. The costs of simulation modeldevelopment could be reduced by the reuse of some of its parts. This work presents a case studyconcerning stochastic modeling of a small manufacture operating into the wood products field. Amodular simulation model composed of reusable sub-models has been developed using AutoMod™software package. The aim of the modular architecture is to allow the use of sub-models in differentproduction systems with little changes, decreasing the costs of development in order to became moreaffordable in a SME (small medium enterprise) contest

    VirtES (Virtual Enterprise Simulator): A proposed methodology for enterprise simulation modeling

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    Abstract. In this paper a methodology to develop simulation models is presented. The methodology is based on a multi-level simulation model which allows flexibility and process analysis. The present work starts from applied researches in different SME enterprises. Enterprise management often needs easy and fast developed tools to increase production capacity and flexibility. In many cases performances increase is possible only adopting a BPR (business processes reengineering) approach. Nevertheless the resistance to a BPR approach is underlined in recent bibliography. The proposed approach consists of a three stages methodology, named VirtES (Virtual Enterprise Simulator). VirtES methodology was first applied to ceramic tiles enterprises. The results achieved encourage the adoption to other industrial field

    Safety evaluations of a synthetic antimicrobial peptide administered intravenously in rats and dogs

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    The antimicrobial peptide SET-M33 is under study for the development of a new antibiotic against major Gram-negative pathogens. Here we report the toxicological evaluation of SET-M33 administered intravenously to rats and dogs. Dose range finding experiments determined the doses to use in toxicokinetic evaluation, clinical biochemistry analysis, necroscopy and in neurological and respiratory measurements. Clinical laboratory investigations in dogs and rats showed a dose-related increase in creatinine and urea levels, indicating that the kidneys are the target organ. This was also confirmed by necroscopy studies of animal tissues, where signs of degeneration and regeneration were found in kidney when SET-M33 was administered at the highest doses in the two animal species. Neurological toxicity measurements by the Irwin method and respiratory function evaluation in rats did not reveal any toxic effect even at the highest dose. Finally, repeated administration of SET-M33 by short infusion in dogs revealed a no-observed-adverse-effect-level of 0.5&nbsp;mg/kg/day

    Amorphous-silicon visible-light detector integrated on silicon nitride waveguides

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    : Visible-light integrated photonics is emerging as a promising technology for the realization of optical devices for applications in sensing, quantum information and communications, imaging, and displays. Among the existing photonic platforms, high-index-contrast silicon nitride (Si3N4) waveguides offer broadband transparency in the visible spectral range and a high scale of integration. As the complexity of photonic integrated circuits (PICs) increases, on-chip detectors are required to monitor their working point for reconfiguration and stabilization operations. In this Letter, we present a semi-transparent in-line power monitor integrated on Si3N4 waveguides that operates in the red-light wavelength range (660 nm). The proposed device exploits the photoconductivity of a hydrogenated amorphous-silicon (a-Si:H) film that is evanescently coupled to an optical waveguide. Experimental results show a responsivity of 30 mA/W, a sensitivity of -45 dBm, and a sub-µs time response. These features enable the use of the proposed photoconductor for high-sensitivity monitoring and control of visible-light Si3N4 PICs

    Midterm results on a new self-expandable covered stent combined with branched stent grafts: Insights from a multicenter Italian registry

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    Objective: To investigate the technical periprocedural and midterm outcomes of endovascular repairs with multibranched endovascular repair or iliac branch devices combined with a new self-expanding covered stent. Methods: The COvera in BRAnch registry is a physician-initiated, multicenter, ambispective, observational registry (ClinicalTrials.gov Identifier: NCT04598802) enrolling patients receiving a multibranched endovascular repair or iliac branch devices procedure mated with Bard Covera Plus (Tempe, AZ) covered stent, designed to evaluate the outcomes of the covered stent mated with patient-specific and off-the-shelf branched stent graft. Primary end points were technical success, branch instability, and freedom from aortic and branch-related reintervention within 30 days and at follow-up. Preoperative characteristics, comorbidities, and outcomes definitions were graded according to the Society for Vascular Surgery reporting standards. Results: Two hundred eighty-four patients (76 years; range, 70-80 years; 79% males) in 24 centers were enrolled for a total of 708 target vessels treated. The covered stents were mated with an off-the-shelf graft in 556 vessels (79%) and a custom-made graft in 152 (21%). Three hundred seven adjunctive relining stents in 277 vessels (39%) were deployed, of which 116 (38%) were proximal, 66 (21%) intrastent, and 125 (41%) distal. Adjunctive relining stent placement was more frequent when landing in a vessel branch instead of the main trunk (59% vs 39%; P = .031), performing a percutaneous access (49% vs 35%; P < .001), using a stent with a diameter of 8 mm or greater (44% vs 36%; P = .032) and a length of 80 mm or greater (65% vs 55%; P = .005), when a post-dilatation was not performed (45% vs 29%; P < .001) and when an inner branch configuration was used (55% vs 35%; P < .001). Perioperative technical bridging success was 98%. Eight patients (3%) died in the perioperative period. Two deaths (1%) were associated with renal branch occlusion followed by acute kidney injury and paraplegia. Follow-up data were available for 638 vessels (90%) at a median of 32 months (Q1, Q3, 21, 46). Branch instability was reported in 1% of branches. Forty-six patients (17%) died during follow-up, nine (3%) of them owing to aortic-related causes. Primary patency rates at 1, 2, and 3 years were 99% (581/587), 99% (404/411), and 97% (272/279), respectively. Branch instability was associated with patient-specific devices (9% vs 4%; P = .014) and intrastent adjunctive stent placement (12% vs 2%; P = .003), especially when a bare metal balloon-expandable stent was used (25% vs 3%; P < .001). Conclusions: The use of this new self-expanding covered stent mated with branched endografts proved to be safe and feasible with high technical procedural success rates. Low rates of branch instability were observed at midterm follow-up. Comparative studies with other commercially available covered stents are warranted

    A proposed correction for the expected service level in the economic order quantity (EOQ) model under relaxed demand assumption

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    The economic order quantity (EOQ) and the economic production quantity (EPQ) are well-known and commonly used inventory control techniques. The standard results are easy to apply but are based on a number of unrealistic assumptions. One of the assumption is that the demand is normally distributed in any interval. In several practical cases the assumption about independence of successive demands, and consequently demand normal distribution in any interval, is not supported by real data. This paper investigates the effects on the expected service level (SL) after relaxing normal distribution assumption on the demand. The present work shows a possible strategy to use classic inventory model, such as EOQ/EPQ model, adopting simulation analysis to quantify model performances under relaxed assumptions
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