Unprompted recall and reporting of hidden objects by a chimpanzee (Pan troglodytes) after extended delays.

The ability to recall features of environments not present to the senses is important in human thinking, planning, and communication, but to date there are almost no data on recall capabilities in nonverbal animals. In this study, the author used symbol knowledge as a tool to study chimpanzee memory. An 11-year-old female chimpanzee (Pan troglodytes) that had already learned a large number of arbitrarily designated geometric forms (lexigrams) watched as an experimenter hid an object in the woods outside her outdoor enclosure. The type and location of the object varied across trials. After an imposed delay of up to 16 h, the chimpanzee could interact indoors with a person who did not know that an object had been hidden, let alone the type or location of the object. A keyboard in the indoor cage displayed 256 lexigrams. From Trial 1, the chimpanzee seemed to do whatever it took to catch the person's attention and then touched the lexigram corresponding to the type of object hidden, pointed outdoors, went outdoors (if followed), and continued to point manually toward the object and vocalize until the person found the object. The subject indicated nonfood objects as well as more than 20 food types. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dose quantities in radiation protection and their limitations

For more than 50 years the quantity absorbed dose has been the basic physical quantity in the medical applications of ionising radiation as well as radiological protection against harm from ionising radiation. In radiotherapy relatively high doses are applied (to a part of the human body) within a short period and the absorbed dose is mainly correlated with deterministic effects such as cell killing and tissue damage. In contrast, in radiological protection one is dealing with low doses and low dose rates and long-term stochastic effects in tissue such as cancer induction. The dose quantity (absorbed dose) is considered to be correlated with the probability of cancer incidence and thus risk induced by exposure. ICRP has developed specific dosimetric quantities for radiological protection that allow the extent of exposure to ionising radiation from whole and partial body external radiation as well as from intakes of radionuclides to be taken into account by one quantity. Moreover, radiological protection quantities are designed to provide a correlation with risk of radiation induced cancer. In addition, operational dose quantities have been defined for use in measurements of external radiation exposure and practical applications. The paper describes the concept and considerations underlying the actual system of dose quantities, and discusses the advantage as well as the limitations of applicability of such a system. For example, absorbed dose is a non-stochastic quantity defined at any point in matter. All dose quantities in use are based on an averaging procedure. Stochastic effects and microscopic biological and energy deposition structures are not considered in the definition. Absorbed dose is correlated to the initial very short phase of the radiation interaction with tissue while the radiation induced biological reactions of the tissue may last for minutes or hours or even longer. There are many parameters other than absorbed dose that influence the process of cancer induction, which may influence the consideration of cells and/or tissues at risk which are most important for radiological protection.     

Fabrication and characterization of platinum nanoparticle arrays of controlled size, shape and orientation

We present a rigorous approach for the shape design of supported metal nanoparticle catalysts, morphologically identical to each other and epitaxially grown on strontium titanate substrates using electron beam lithography. We predict the particle shapes using Wulff construction based on density functional theory calculations of surface energies. Then, according to the theoretical predictions, we are able to tweak morphologies of the already produced nanocrystals by changing annealing conditions. The ability to design, produce and characterize the catalyst nanoparticles allows us to relate microscopic morphologies with macroscopic oxygen-reduction activities in perchloric acid [Komanicky et al., J. Am. Chem. Soc. 131 (2009) 5732]. The unexpectedly high oxygen-reduction activities proportional to inactive (1 0 0) facets led us to suggest a model where the reaction intermediates can cross over to neighboring facets in nanoscale proximity.     

A cohort study of sciatic pain and measures of internal spinal load in professional drivers

In a prospective cohort study of 537 male professional drivers, the occurrence of sciatic pain showed stronger associations with measures of internal lumbar load expressed in terms of daily compressive dose, S_ed (MPa), and risk factor, R (non-dimensional), according to ISO/WD 2631-5 (2013), than with measures of daily vibration exposure calculated as either 8-h energy-equivalent frequency-weighted acceleration (ms^? 2 r.m.s.) or vibration dose value (ms^? 1.75) according to the EU Directive on mechanical vibration (2002). Herniated lumbar disc, previous lumbar trauma and physical work load were also powerful predictors of the occurrence of sciatic pain over time. Psychosocial work environment was poorly associated with sciatic pain. The boundary values of risk factor (R) for low and high probabilities of adverse health effects on the lumbar spine, as proposed by international standard ISO/WD 2631-5 (2013), tend to underestimate the health risk in professional drivers.     

Amythiamicin D and Related Thiopeptides as Inhibitors of the Bacterial Elongation Factor EF‐Tu: Modification of the Amino Acid at Carbon Atom C2 of Ring C Dramatically Influences Activity

Three analogues of amythiamicin D, which differ in the substitution pattern at the methine group adjacent to C2 of the thiazole ring C, were prepared by de novo total synthesis. In amythiamicin D, this carbon atom is (S)‐isopropyl substituted. Two of the new analogues carry a hydroxymethyl in place of the isopropyl group, one at an S‐ (compound 3 a ) and the other at an R‐configured stereogenic center ( 3 b ). The third analogue, 3 c , contains a benzyloxymethyl group at an S‐configured stereogenic center. Compounds 3 b and 3 c showed no inhibitory effect toward various bacterial strains, nor did they influence the translation of firefly luciferase. In stark contrast, compound 3 a inhibited the growth of Gram‐positive bacteria Staphylococcus aureus (strains NCTC and Mu50) and Listeria monocytogenes EGD. In the firefly luciferase assay it proved more potent than amythiamicin D, and rescue experiments provided evidence that translation inhibition is due to binding to the bacterial elongation factor Tu (EF‐Tu). The results were rationalized by structural investigations and by molecular dynamics simulations of the free compounds in solution and bound to the EF‐Tu binding site. The low affinity of compound 3 b was attributed to the absence of a critical hydrogen bond, which stabilizes the conformation required for binding to EF‐Tu. Compound 3 c was shown not to comply with the binding properties of the binding site.     

Assessment of the Cytocompatibility of Poly‐(N‐hexylvinylpyridinium) Used as an Antibacterial Implant Coating

Medical implants made of titanium have a wide variety of applications, ranging from replacement of a single tooth to extraoral maxillofacial prosthetic rehabilitation or hip endoprosthesis. The long‐term success of such osseointegrated titanium implants is endangered by inflammation of periimplant hard or soft tissues caused by a bacterial infection. Therefore, implants should ideally inhibit bacterial adhesion and growth, but allows strong attachment of connective tissues or epithelium at the same time. Antimicrobial polymers like poly(vinyl‐N‐hexylpyridinium bromide) (hexyl‐PVP) are a promising approach as implant coatings to inhibit bacterial adhesion, but little is known about the biocompatibility of these polymers. The aim of the present study was to develop a method for evaluation of the cell acceptance of hexyl‐PVP or copolymers of vinyl‐N‐hexylpyridinium bromide and (4‐vinylbenzyl)phosphonic acid diethylester (poly((hexyl‐VP)‐co‐VBP)) as coating on titanium disks. Primary human gingival fibroblasts were used and biocompatibility was assessed by cell adhesion and proliferation. The cell morphology of the fibroblasts on these surfaces was analyzed by scanning electron microscopy (SEM) and was used as additional criterion. The results indicate no significant differences in adhesion or proliferation rate between primary human gingival fibroblasts seeded on polymer‐coated titanium disks and uncoated titanium disks as a control. Although SEM micrographs displayed moderate differences in cell morphology between the two groups, application of hexyl‐PVP or the corresponding copolymers as antibacterial coatings for medical implants or devices appears to be promising.     

IV. Referate

Ohne Zusammenfassung     

Investigation of the migration behavior of polyisobutylene with various molecular weights in ethylene/α‐olefin copolymer blown stretch films for improved cling properties

High retention forces are the basic requirements on stretch films for agricultural or pallet wrapping of goods and significantly influenced by cling properties (autohesion) that are essential for a reliable load stability during transportation and storage. Low molecular weight polyisobutylene (PIB) has tacky properties and is immiscible with polyethylene. Blended with ethylene/α‐olefin copolymers in coextruded stretch films, PIB can migrate to the film surfaces and cause cling properties. Cling and adhesion forces were investigated using the mechanical cling test, atomic force, and scanning electron microscopy and infrared spectroscopy. The molecular weight of the PIB as well as density and crystallinity of the matrix material have strong influences on migration kinetics and therefore, on the cling forces. Cling forces increase with increasing aging time, having a maximum after 2 weeks of production. The following slight decrease of the cling force might be correlated with a beginning degradation process of the UV sensitive PIB. Polyisobutylene with higher molecular weight diffuses slower through a linear low density polyethylene (LLDPE) matrix than lower molecular weight PIB, but can cause higher cling forces on the film surfaces. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40239.