Potential Mechanisms Linking Atherosclerosis and Increased Cardiovascular Risk in COPD: Focus On Sirtuins

The development of atherosclerosis is a multi-step process, at least in part controlled by the vascular endothelium function. Observations in humans and experimental models of atherosclerosis have identified monocyte recruitment as an early event in atherogenesis. Chronic inflammation is associated with ageing and its related diseases (e.g., atherosclerosis and chronic obstructive pulmonary disease). Recently it has been discovered that Sirtuins (NAD⁺-dependent deacetylases) represent a pivotal regulator of longevity and health. They appear to have a prominent role in vascular biology and regulate aspects of age-dependent atherosclerosis. Many studies demonstrate that SIRT1 exhibits anti-inflammatory properties in vitro (e.g., fatty acid-induced inflammation), in vivo (e.g., atherosclerosis, sustainment of normal immune function in knock-out mice) and in clinical studies (e.g., patients with chronic obstructive pulmonary disease). Because of a significant reduction of SIRT1 in rodent lungs exposed to cigarette smoke and in lungs of patients with chronic obstructive pulmonary disease (COPD), activation of SIRT1 may be a potential target for chronic obstructive pulmonary disease therapy. We review the inflammatory mechanisms involved in COPD-CVD coexistence and the potential role of SIRT1 in the regulation of these systems.     

Electrochemical hydrodehalogenation of polychloromethanes at silver and carbon electrodes

The reductive dehalogenation of CCl₄, CHCl₃, CH₂Cl₂ and CH₃Cl has been investigated by cyclic voltammetry and controlled-potential electrolysis at Ag, glassy carbon (GC) and graphite electrodes in dimethylformamide (DMF) + 0.1 M Et₄NClO₄ in the absence and presence of a proton donor. In particular, the study was focused in the evaluation of the intermediates and final products of the reduction process and how their distribution could be affected by tuning relevant chemical and electrochemical parameters. In general, depending on the value of the applied potential, all polychloromethanes (PCMs) can be partially or completely dechlorinated, methane being exclusively formed in the latter case. The nature of the electrode material and the proton availability of the medium affect drastically the distribution of reduction products. The results point out that at both types of electrode, reduction of PCMs takes place through two competing reaction pathways both leading to methane. One reaction route involves a sequence of reductive dehalogenation steps, with the removal of one chlorine atom at a time, whereas the other is based on hydrogenolysis of carbenes and bypasses the intermediacy of partially dechlorinated PCMs. The presence of a proton source affects substantially the hydrodehalogenation efficiency, enhancing the concentration of intermediate PCMs and the final yield of methane. The silver electrode exhibits an extraordinary electrocatalytic effect resulting in remarkable positive shifts of the reduction potentials of all PCMs with respect to GC. The Ag surface strongly affects the kinetics of the dissociative electron transfer to CH_nCl_(4−n) (n = 0–3) as well as the reactivity of the intermediate radicals, carbanions and carbenes.     

Zeolites in biomedical application: Zn-exchanged clinoptilolite-rich rock as active carrier for antibiotics in anti-acne topical therapy

A clinoptilolite-rich rock was evaluated as inorganic Zn²⁺ releasing carrier for antibiotic erythromycin. The perspective is its use in the topical treatment of acne, a diffused skin pathology, given the efficacy of zinc-erythromycin combination against resistant Propionibacterium strains. The tested rock is an ash-rich epiclastite collected in Northern–Central part of Sardinia island (Italy). ICP chemical analyses of the bulk rock evidenced a composition compatible with topical applications. A 66 wt.% of clinoptilolite content was determined by means of XRD analysis (reference intensity ratio [RIR] technique). EDS chemical analyses of zeolite crystals were performed on polished thin section. The CEC of the rock is 1.45±0.08 meq/g. Using a specific exchange method, the material was previously Na-conditioned then Zn-conditioned. A substantially complete Zn-form was obtained, as demonstrated by AAS analyses. A back-exchange reaction toward Na-form was performed in the same conditions (65 °C in 1 M NaCl solution): zinc release was fast and almost complete (94%). Zn-conditioned powder was then micronized to achieve a volume/surface ratio suitable for a topical therapy. After micronization, the specific surface area, determined by BET gas adsorption, was 30.2 m²/g, and 92% of the powdered rock was lower than 30 μm in size (measured by a Coulter Counter apparatus); the so-called “volume-surface diameter” was 6.48 μm, compatible with the intended topical application. Zn²⁺ release was measured on micronized rock at 37 °C both in physiologic solution as in 0.05 M KH₂PO₄/Na₂HPO₄ buffer. Also in these conditions, a prompt and significant zinc release was recorded: after 30 min, 68% and 60%, respectively. Erythromycin was charged onto the micronized material using a solvent evaporation method. HPLC determinations showed that 85% of the drug contacted with the carrier was loaded. The simultaneous release of zinc and erythromycin were evaluated in phosphate buffer. Eighty-two percent of the loaded antibiotic was released after 30 min. Zinc exchange is substantially unaffected by the contemporary drug release. The request to file an international patent for this pharmaceutical application has been accepted by the European International Preliminary Examination Office.     

Switched Dual Diversity Reception of M-ary DPSK Signals on Nakagami Fading Channels

The paper deals with dual diversity reception of M-ary differential phase-shift keying modulated signals in the presence of additive white Gaussian noise and Nakagami-distributed slow and nonselective fading. The performance of a switched diversity system is analysed and compared to that of the predetection selection diversity combining scheme. The general case of correlated diversity branches is considered, without restrictions on the fading severity parameter. Average symbol error rate formulas are analytically derived in terms of integral expressions that can be easily computed via numerical integration routines. Moreover, the numerical evaluation of the optimum switching threshold is carried out and the influence of the fading severity parameter, the branch correlation, and the cardinality of the symbol alphabet is analysed. Finally, three fixed switching threshold strategies that allow to obtain a satisfactory diversity gain are considered.     

An expanded neonatal morbidity scale for premature infants

We revised a neonatal morbidity scale (the NMS) that has served as a means for comparison of neonatal illness in studies of high-risk neonates after initial hospital discharge. With an inception cohort approach, 89 premature infants at an urban university hospital were studied with the expanded scale (the ENMS). The original scale, published in 1983, was reworked and expanded based on advances in the diagnosis and management of neonates. A social risk scale was added. Linear and logistic regression analyses were used to judge validity of the newly revised scale and to examine its predictive ability for outcomes at six months of age. Concurrent validity was supported by the relationship between the ENMS-SRS and: birthweight (R2 = .54), gestational age (R2 = .50), length of stay (R2 = .47). Inter-rater reliability was .95. The ENMS, embodying a contemporary patient profile, is valid for a population of premature infants in a U.S. urban setting and has predictive validity for a few outcomes within six months of discharge from a special care unit.     

Securing Threshold Cryptosystems against Chosen Ciphertext Attack

For the most compelling applications of threshold cryptosystems, security against chosen cipher text attack is a requirement. However, prior to the results presented here, there appeared to be no practical threshold cryptosystems in the literature that were provably chosen ciphertext secure, even in the idealized random oracle model. The contribution of this paper is to present two very practical threshold cryptosystems, and to prove that they are secure against chosen ciphertext attack in the random oracle model. Not only are these protocols computationally very efficient, but they are also non-interactive, which means they can be easily run over an asynchronous communication network. Received November 2000 and revised September 2001 Online publication 11 March 2002     

Film Structure of Epitaxial Graphene Oxide on SiC: Insight on the Relationship Between Interlayer Spacing,Water Content,and Intralayer Structure

Chemical oxidation of multilayer graphene grown on silicon carbide yields films exhibiting reproducible characteristics, lateral uniformity, smoothness over large areas, and manageable chemical complexity, thereby opening opportunities to accelerate both fundamental understanding and technological applications of this form of graphene oxide films. Here, we investigate the vertical inter‐layer structure of these ultra‐thin oxide films. X‐ray diffraction, atomic force microscopy, and IR experiments show that the multilayer films exhibit excellent inter‐layer registry, little amount (<10%) of intercalated water, and unexpectedly large interlayer separations of about 9.35 Å. Density functional theory calculations show that the apparent contradiction of “little water but large interlayer spacing in the graphene oxide films” can be explained by considering a multilayer film formed by carbon layers presenting, at the nanoscale, a non‐homogenous oxidation, where non‐oxidized and highly oxidized nano‐domains coexist and where a few water molecules trapped between oxidized regions of the stacked layers are sufficient to account for the observed large inter‐layer separations. This work sheds light on both the vertical and intra‐layer structure of graphene oxide films grown on silicon carbide, and more in general, it provides novel insight on the relationship between inter‐layer spacing, water content, and structure of graphene/graphite oxide materials.     

Radon in workplaces: first results of an extensive survey and comparison with radon in homes

Extensive radon surveys have been carried out in many countries only in dwellings, whereas surveys in workplaces are rather sparse and generally restricted to specific workplaces/activities, e.g. schools, spas and caves. Moreover, radon-prone areas are generally defined on the basis of radon surveys in dwellings, while radon regulations use this concept to introduce specific requirements in workplaces in such areas. This approach does not take into account that work activities and workplace characteristics can significantly affect radon concentration. Therefore, an extensive survey on radon in different workplaces have been carried out in a large region of Italy (Tuscany), in order to evaluate radon distribution in workplaces over the whole territory and to identify activities and workplace characteristics affecting radon concentration. The results of this extensive survey are compared with the results of the survey carried out in dwellings in the same period. The workplaces monitored were randomly selected among the main work activities in the region, including both public and industrial buildings. The survey monitored over 3500 rooms in more than 1200 buildings for two consecutive periods of ～6 months. Radon concentration was measured by means of passive nuclear track detectors.