Heuristic algorithms for a storage location assignment problem in a chaotic warehouse

The extensive application of emerging technologies is revolutionizing warehouse management. These technologies facilitate working with complex and powerful warehouse management models in which products do not have assigned fixed locations (random storage). Random storage allows the utilization of the available space to be optimized. In this context, and motivated by a real problem, this article presents a model that looks for the optimal allocation of goods in order to maximize the storage space availability within the restrictions of the warehouse. For the proposed model a construction method, a local search algorithm and different metaheuristics have been developed. The introduced algorithms can also be used for other purposes such as to assess when and how it is convenient to perform relocation of stored items to improve the current level of storage space availability. Computational tests performed on a set of randomly generated and real warehouse instances show the effectiveness of the proposed methods.     

Asymptotic behavior of robust estimators in partially linear models with missing responses: the effect of estimating the missing probability on the simplified marginal estimators

In this paper, we consider a semiparametric partially linear regression model where missing data occur in the response. We derive the asymptotic behavior of the robust estimators for the regression parameter and of the weighted simplified location estimator introduced in Bianco et al. (Comput. Stat. Data Anal. 54:546–564, 2010a). For the latter, consistency results and the asymptotic distribution are derived when the missing probability is known and also when it is estimated.     

Cellular uptake and cytotoxic impact of chemically functionalized and polymer-coated carbon nanotubes

The impact of nanomaterials such as carbon nanotubes on biological matter is a topic of increasing interest and concern and requires a multifaceted approach to be resolved. A modified cytotoxic (lactate dehydrogenase (LDH)) assay is developed in an attempt to offer a valid and reliable methodology for screening carbon nanotube toxicity in vitro. Two of the most widely used types of surface-modified multiwalled carbon nanotubes (MWNTs) are tested: ammonium-functionalized MWNTs (MWNT-NH3+ ) and Pluronic F127 coated MWNTs (MWNT:F127). Chemically functionalized MWNTs show significantly greater cellular uptake into lung epithelial A549 cells compared to the non-covalently Pluronic F127-coated MWNTs. In spite of this, MWNT:F127 exhibit enhanced cytotoxicity according to the modified LDH assay. The validity of the modified LDH assay is further validated by direct comparison with other less reliable or accurate cytotoxicity assays. These findings indicate the reliability of the modified LDH assay as a screening tool to assess carbon nanotube cytotoxicity and illustrate that high levels of carbon nanotube cellular internalization do not necessarily lead to adverse responses.     

Functionalized carbon nanotubes are non-cytotoxic and preserve the functionality of primary immune cells

Carbon nanotubes are emerging as innovative tools in nanobiotechnology. However, their toxic effects on environment and health have become an issue of strong concern. In the present study, we address the impact of functionalized carbon nanotubes (f-CNTs) on cells of the immune system. We have prepared two types of f-CNTs, following the 1,3-dipolar cycloaddition reaction (f-CNTs 1 and 2) and the oxidation/amidation treatment (f-CNTs 3 and 4), respectively. We have found that both types of f-CNTs are uptaken by B and T lymphocytes as well as macrophages in vitro, without affecting cell viability. Subsequently, the functionality of the different cells was analyzed carefully. We discovered that f-CNT 1, which is highly water soluble, did not influence the functional activity of immunoregulatory cells. f-CNT 3, which instead possesses reduced solubility and forms mainly stable water suspensions, preserved lymphocytes' functionality while provoking secretion of proinflammatory cytokines by macrophages.     

Diagnosis of hereditary hemochromatosis with molecular analysis of DNA in patients with anti-HCV positive liver cirrhosis. Clinical case

A case of hereditary hemochromatosis in a patient affected by anti-HCV positive liver cirrhosis is described. The difficulties for an exact diagnosis are underlined. Really, it can be particularly difficult to make a differential diagnosis between hereditary hemochromatosis and secondary hemochromatosis, if liver cirrhosis has already been found. Practically, at this stage of disease, the histological and clinical aspects of these two forms become completely interchangeable. Moreover, diagnostic difficulties increase when, at the same time, the patient presents more causes of potential liver damage. In this case report, the DNA-analysis, obtained by polymerase chain reaction amplification and enzymatic digestion, allows to make the diagnosis of hereditary hemochromatosis, because it showed the presence of two genetic mutations, considered responsible for the disease. Both the hereditary hemochromatosis and the HCV infection, had greatly contributed to the development of liver cirrhosis. In the future, DNA-analysis by amplification with polymerase chain reaction, can assume relevant importance for the screening of affected patients' first grade parents too. It could permit an early diagnosis of hereditary hemochromatosis and then to start a timelier and more efficacious therapy, to prevent an irreversible histological damage.