352 research outputs found

    Organic Solar Cells: Problems and Perspectives

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    For photovoltaic cells to convert solar into electric energy is probably the most interesting research challenge nowadays. A good efficiency of these devices has been obtained by using inorganic semiconductor materials. On the other hand, manufacture processes are very expensive in terms of both materials and techniques. For this reason organic-based photovoltaic (OPV) cells are attracting the general attention because of the possible realization of more economical devices. Organic materials are abundant and easily handling. Unfortunately OPV cells efficiency is significantly lower than that of inorganic-based devices, representing a big point of weakness at the present. This is mainly due to the fact that organic semiconductors have a much higher band gap with respect to inorganic semiconductors. In addition, OPV cells are very susceptible to oxygen and water. In this paper we will describe some of the different approaches to the understanding and improving of organic photovoltaic devices

    The digitalization of supply chain: A review

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    The emergence of new digital technologies as part of Industry 4.0 has enabled the supply chain to be managed more efficiently. We talk about digitalization of the supply chain and this trend refers to the evolution towards a smarter model that involves digital technologies such as Blockchain, IoT, Machine Learning, etc. These technologies actually increase and enhance the ability to optimize planning, sourcing and procurement strategies. Since this topic is of relevant interest for the scientific community, this paper aims to investigate the main discussion themes related to supply chain digitalization using a keyword-based organizing framework to identify, classify and investigate relevant intellectual contributions in this field. Results showed which are the main issues regarding supply chain digitalization as well as promising future research avenues

    Assessment of students\u27 knowledge of Internet risk and Internet behaviors: Potential threats to bullying and contact by Internet predators

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    Given the serious issue of bullying, this study sought to assess middle and high school students\u27 knowledge of appropriate use and their behaviors on the Internet and social networking sites, especially regarding behaviors that may lead to cyberbullying or contact with potential Internet predators. Three school districts (urban, suburban, and urban ring) with grades 6 - 12 are participating in this study. Differences among and between grade levels, gender, and school demographics at the dimension and item-level will be presented

    Parental Involvement in Students’ Safe Use of the Internet

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    The purpose of this study was to investigate if parental involvement in digital activities relates to middle school students’ knowledge of appropriate use of the Internet and social networking sites. Parental involvement, measured using a three-item dimension on the 40 item instrument, asked students to report on their knowledge of their parent’s involvement with their internet activity. The aggregate score on this dimension was used to measure the relationship among several dimensions. Furthermore, demographic items, such as grade level, having an older sibling, and getting in trouble at school, were also investigated. Over 71% of adults in the United States use the Internet (Horigan, 2007). Research suggests that adolescence (namely teens), are heavier users than adults (Subrahmanyam, Kraut, Greenfield, & Gross, 2001). Actually, in the United States, it is estimated that 21 million teens use the Internet. This represents 87% of this age group (Lenhart, 2005). Student have access to the Internet readily available, be it school, home, or library. This ease of access may increase the potential for students to become victims of Internet sexual predators or other students who engage in inappropriate cyberbullying behaviors. Rainie (2008) found that 32% of teens reported being contacted on-line by a stranger. Furthermore, 23% (of the 32%) stated that the contact made them feel scared or uncomfortable. There is a myriad of evidence to support the need for parental involvement in a child’s internet activities, from filtering access to monitoring activity, supervision is paramount (Lenhardt, 2005; Raine, 2008; Shariff 2008). Aside from the fact that predators are seeking young predators, teens are also reporting inappropriate behaviors. In fact, Lenhardt found that 81% of parents and 79% of teens agreed that “teens are not careful enough when sharing personal information on-line” (pii). Furthermore, when asked if “teens do things online that they wouldn’t want their parents to know about” (pii), 65% of the parents and 64% of the teens agreed with the statement. The knowledge of the issue is evident from both parties, so now what do we do with it? This line of research aims to understand the status of behaviors and views of middle school students and the influence parents have on these behaviors. It is hoped that the results may assist schools in developing educational programs and safeguards to protect students

    Argas (Persicargas) persicus (Oken, 1818) (Ixodida: Argasidae) in Sicily with considerations about its Italian and West-Mediterranean distribution.

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    Recently, in the province of Trapani (Western Sicily), some overwintering specimens of the argasid tick Argas (Persicargas) persicus (Oken, 1818) were observed and collected. Morphological and genetic analysis were utilized in order to reach a definitive identification. The species was found in two semi-natural sites where, having been found repeatedly, its presence does not appear accidental. Moreover the characteristics of the Sicilian findings seem to exclude a human-induced spread. This record, the first regarding Sicily and South Italy, is discussed together with the previous doubtful citations for Italy. These findings revalue not only all the old citations for Italy but also the hypothesis that the Mediterranean distribution of this argasid is of a natural origin

    Corneal epithelial wound healing promoted by verbascoside-based liposomal eyedrops

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    Different liposomal formulations were prepared to identify those capable of forming eyedrops for corneal diseases. Liposomes with neutral or slightly positive surface charge interact very well with the cornea. Then these formulations were loaded with verbascoside to heal a burn of corneal epithelium induced by alkali. The cornea surface affected involved in wound was monitored as a function of time. Experimental results were modeled by balance equation between the rate of healing, due to the flow of phenylpropanoid, and growth of the wound. The results indicate a latency time of only three hours and furthermore the corneal epithelium heals in 48 hours.Thus, the topical administration of verbascoside appears to reduce the action time of cells, as verified by histochemical and immunofluorescence assays

    Fluorescein angiography findings in eyes with lamellar macular hole and epiretinal membrane foveoschisis

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    PURPOSE. The purpose of this paper was to study fluorescein angiography (FA) findings in eyes with lamellar macular hole (LMH), and epiretinal membrane (ERM) foveoschisis. METHODS. In this prospective, observational case series, 46 eyes of patients affected by either LMH or ERM foveoschisis were examined using optical coherence tomography (OCT) and FA. All patients underwent a comprehensive ophthalmological examination and a general workup to exclude uveitis. Main outcome measures were: presence of FA abnormalities, measurements of the areas of vascular leakage, and intensity of pixels in the vitreous. RESULTS. Twenty-four (52.2%) eyes with LMH and 22 (47.8%) with ERM foveoschisis were studied. Overall, FA abnormalities were found in 20 (83.3%) eyes with LMH and 18 (81.8%) with ERM foveoschisis. The median areas of posterior pole and peripheral leakage were 7.52 vs. 1.07 mm2 (P = 0.03) and 21.8 vs. 3.74 mm2 (P = 0.02) in the LMH and ERM foveoschisis group, respectively. Disk hyperfluorescence was found in 8 and 4 eyes and perivascular leak in 10 and 4 eyes with LMH and ERM foveoschisis, respectively. OCT-derived measurements of vitreous intensity did not differ between the two groups, and the investigational workup for uveitis was negative in all patients. CONCLUSIONS. Discrete areas of central and peripheral leakage are commonly found in eyes with LMH and ERM foveoschisis, whereas perivascular leak and hyperfluorescence of the disc are less frequently observed. These findings suggest that breakdown of the retinal blood barrier, involving the posterior pole and the periphery, is frequently associated with these two vitreoretinal disorders

    Oxaliplatin plus high-dose folinic acid and 5-fluorouracil i.v. bolus (OXAFAFU) versus irinotecan plus high-dose folinic acid and 5-fluorouracil i.v. bolus (IRIFAFU) in patients with metastatic colorectal carcinoma: a Southern Italy Cooperative Oncology Group phase III trial

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    The primary end point of this phase III trial was to compare the response rate (RR) of oxaliplatin (OXA) plus levo-folinic acid (l-FA) and 5-fluorouracil (5-FU) bolus with that of irinotecan (IRI) plus l-FA and 5-FU bolus in advanced colorectal carcinoma

    Randomized Phase II Trial of weekly paclitaxel alone versus trastuzumab plus weekly paclitaxel as first-line therapy of patients with Her-2 positive advanced breast cancer.

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    BACKGROUND: A randomized Phase II study evaluated the activity of weekly paclitaxel versus its combination with trastuzumab for treatment of patients with advanced breast cancer overexpressing HER-2. PATIENTS AND METHODS: Among 124 patients randomized, 123 are assessable for toxicity and 118 for response. Patients received weekly paclitaxel single agent (80 mg/m2) or combined with trastuzumab (4 mg/kg loading dose, then weekly 2 mg/kg). HER-2 overexpression was determined by immunohistochemistry (IHC). Patients with 2+/3+ IHC scores were eligible. IHC was compared with HER-2 serum extracellular domain (ECD). RESULTS: Patient characteristics were similar in the two arms. Both treatments were feasible and well tolerated with no grade 4 hematologic toxicity. No patient developed cardiac toxicity. The combined treatment was statistically significant superior for overall response rate (ORR) (75% vs. 56.9%; P = 0.037), particularly in the subset of IHC 3+ patients (84.5% vs. 47.5%; P = 0.00050). A statistically significant better median time to progression was seen in the subgroup with IHC 3+ (369 vs. 272 days; P = 0.030) and visceral disease (301 vs. 183 days; P = 0.0080) treated with combination. Multivariable analysis of predictive factors showed that only IHC score retained statistically significant value for ORR (P = 0.0035). CONCLUSION: Weekly paclitaxel plus trastuzumab is highly active and safe and it is superior to paclitaxel alone in patients with IHC score of 3+
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