Powder bed generation in integrated modelling of additive layer manufacturing of orthopaedic implants

This paper presents an original model of powder bed generation developed within the frame of an integrated modelling approach for studying the interaction of physical mechanisms in additive layer manufacturing (ALM) of orthopaedic implants. The model is based on cellular automata (CA) approach and describes the relationship between moving particles of different sizes during deposition on a surface in three dimensions. The surface is defined by the horizontal two-dimensional CA on which particles fall and irreversibly stick to a growing deposit. The model allows for consideration of different restructuring cases when particles are allowed to rotate as often as necessary until achievement of a local minimum position. Changes in the packing density of the powder bed have been investigated numerically depending on technological parameters, such as particle size distribution, deposition rate and sequence of powder deposition. The model has been developed with the aim of merging to the finite element (FE)-based integrated model and is applicable to a different ranges of materials including metals and also non-metals

Detection of Leptospires serogroups, Which Are Common Causes of Human Acute Leptospirosis in Guilan, Northern Iran

"nBackground: This study is performed to reveal most common species and subspecies of leptospires that are main causes of hu­man leptospirosis in Guilan, Northern Province of Iran. "nMethods: We performed IgM-ELISA and MAT on 282 blood samples from patients who attended to 3 hospitals in the flat area of Guilan Province with clinical symptoms consisted with leptospirosis.  All specimens with titers ≥ 160 against at least one pathogenic strain in MAT and with titers ≥160 in IgM-ELISA were regarded confirmed positive cases indicative acute dis­ease. For any confirmed positive cases, we determined the strains, which had the highest titer to determine the frequency of most common serovars and serogroups. "nResults: Seventy of 282 sera had titers ≥160 against at least one pathogenic strain in MAT and titers ≥ 160 in IgM-ELISA. We determined frequency of common causative serogroups which had highest titers in 70 positive cases and only cases which had high titers in MAT and in IgM-ELISA were selected which is a reliable criterion to detect acute disease and to deter­mine causative serogroup."nConclusion: Nine serogroups including sejroe, grippotyphosa, mini, ictero haemorrhagiae, celledoni, autumnalis, cynopteri, pomona, and javanica were more responsible of acute leptospirosis in Guilan

Genetic diversity and antimicrobial susceptibility of Nocardia species among patients with nocardiosis

The aim of this multicenter study was to determine the genetic diversity and antibiotic susceptibility of clinically isolated Nocardia species. One hundred twenty-seven patients with nocardiosis were randomly selected from 5 provinces of Iran. Molecular diagnosis of Nocardia species was performed using multilocus sequence analysis of gyrase B of the β subunit of DNA topoisomerase (gyrB), and 16S rRNA and subunit A of SecA preproteintranslocase (secA1). Antimicrobial susceptibility testing was performed following the Clinical and Laboratory Standards Institute recommendations. Thirty-five N. cyriacigeorgica, 30 N. asteroides, 26 N. farcinica, 12 N. otitidiscaviarum, and 10 N. abscessus cultures were studied. All isolates were susceptible to linezolid. All isolates of N. cyriacigeorgica, N. asteroides, N. abscessus, and N. otitidiscaviarum were susceptible to trimethoprim-sulfamethoxazole, while 8% of N. farcinica isolates were resistant to this drug. All N. otitidiscaviarum isolates were highly resistant to imipenem, but N. cyriacigeorgica, N. asteroides, N. farcinica, and N. abscessus were only moderate resistant. The susceptibility patterns vary with different species of Nocardia. Resistance to trimethoprim-sulfamethoxazole in Iran is low and this drug should be first line therapy, unless drug susceptibility testing shows resistance. Linezolid also covers Nocardia well and could be a second line agent