Period and toroidal knot mosaics

Knot mosaic theory was introduced by Lomonaco and Kauffman in the paper on `Quantum knots and mosaics' to give a precise and workable definition of quantum knots, intended to represent an actual physical quantum system. A knot (m,n)-mosaic is an $m \! \times \! n$ matrix whose entries are eleven mosaic tiles, representing a knot or a link by adjoining properly. In this paper we introduce two variants of knot mosaics: period knot mosaics and toroidal knot mosaics, which are common features in physics and mathematics. We present an algorithm producing the exact enumeration of period knot (m,n)-mosaics for any positive integers m and n, toroidal knot (m,n)-mosaics for co-prime integers m and n, and furthermore toroidal knot (p,p)-mosaics for a prime number p. We also analyze the asymptotics of the growth rates of their cardinality

Biological and structural characterizations of mutations in X-linked spondyloepiphyseal dysplasia tarda

Spondyloepiphyseal dysplasia tarda (SEDT), an X-linked genetic disease manifesting itself in a disproportionate skeletal structure, is caused by mutations in the SEDL gene. Four missense mutations (S73L, V130D, F83S, and D47Y) have been identified by molecular diagnosis as disease-causing SEDT. Nevertheless, how SEDL mutations disrupt the skeletal structure and cause disease remains unknown. We report here the cloning, expression, and characterization of three different missense mutations (S73L, V130D, and D47Y) in mouse SEDL. The overexpression of the D47Y mutation was mainly observed in the supernatant but those of the S73L and V130D mutations are shown in the insoluble pellets. The substitution of the S73L mutation induces the exposure to hydrophobic amino acids and causes aggregation. That of V130D might break hydrophobic interaction and decrease the secondary structure. The CD spectra of three mutants (S73L, V130D, and D47Y) showed that the a-helices decreased more than that of wild-type SEDL. The F83S (stop) mutant might suggest a large conformational change as the mutant V130D. In order to visualize conformational changes in mutated structures, we used molecular modeling techniques minimizing the total energy. These results could provide the biological characterization and conformational information of the SEDL mutants and suggest the clinical severity of the disorder among human SEDL patients

Work-Related Perceptions, Injuries, and Musculoskeletal Symptoms: Comparison Between U.S.-Educated and Foreign-Educated Nurses.

Immigrants account for a significant proportion of the nursing workforce in the United States (U.S.). Although different cultural backgrounds may affect immigrant nurses' perceptions of work and occupational health risks, little research has been conducted. Defining immigrant nurses as those who received initial nursing education in foreign countries, this study examined the differences in work-related perceptions and experiences of musculoskeletal (MS) symptoms and injuries between U.S.-educated and foreign-educated nurses. We analyzed data from a cross-sectional study using a statewide random sample of 419 California registered nurses. Foreign-educated nurses reported a more positive safety climate (p = .017) and perceived their jobs as less demanding (p = .008) than did U.S.-educated nurses. The prevalence of work-related MS symptoms was significantly lower in foreign-educated nurses than in U.S.-educated nurses (p = .044), but the difference was not significant in the multivariable analyses. Positive safety climate was significantly associated with a decreased risk of work-related MS symptoms and injuries, and this relationship was greater among U.S.-educated nurses than among foreign-educated nurses. Our findings suggest that immigrant nurses may have different perceptions about safety climate and job demand, which may modify their occupational health risks

Synergistic Effect between Cryptotanshinone and Antibiotics against Clinic Methicillin and Vancomycin-Resistant Staphylococcus aureus

Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated strong antibacterial activity against clinic isolated methicillin and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) in this experiment. The CT was determined against clinic isolated MRSA 1–16 with MIC and MBC values ranging from 4 to 32 and 8 to 128 μg/mL; for MSSA 1-2 from 16 to 32 μg/mL and 64 to 128 μg/mL; for VRSA 1-2 from 2 to 4 μg/mL and 4 to 16 μg/mL, respectively. The range of MIC50 and MIC90 of CT was 0.5–8 μg/mL and 4–64 μg/mL, respectively. The combination effects of CT with antibiotics were synergistic (FIC index <0.5) against most of tested clinic isolated MRSA, MSSA, and VRSA except additive, MRSA 4 and 16 in oxacillin, MRSA 6, 12, and 15 in ampicillin, and MRSA 6, 11, and 15 in vancomycin (FIC index < 0.75–1.0). Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 2–6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with ampicillin, oxacillin, or vancomycin. The results suggest that CT could be employed as a natural antibacterial agent against multidrug-resistant pathogens infection

Fishbone-Associated Actinomycosis of the Anterior Cervical Space: A Diagnostic Dilemma

We report the imaging and pathologic findings of fishbone-associated actinomycosis of the anterior cervical space in a 57-year-old man, misdiagnosed preoperatively as a malignancy originating from thyroglossal duct cyst. CT revealed an enhancing mass containing a small abscess pocket and two sharp linear calcifications within it, which infiltrated into the strap muscle. Pathologic examination demonstrated two fishbones within the actinomycotic abscess. Fishbone-associated actinomycosis should be considered when a cervical mass contains sharp linear calcifications