Correlation between morphology, electron band structure, and resistivity of Pb atomic chains on the Si(5 5 3)-Au surface.

Structural and electron transport properties of multiple Pb atomic chains fabricated on the Si(5 5 3)-Au surface are investigated using scanning tunneling spectroscopy, reflection high electron energy diffraction, angular resolved photoemission electron spectroscopy and in situ electrical resistance. The study shows that Pb atomic chains growth modulates the electron band structure of pristine Si(5 5 3)-Au surface and hence changes its sheet resistivity. Strong correlation between chains morphology, electron band structure and electron transport properties is found. To explain experimental findings a theoretical tight-binding model of multiple atomic chains interacting on effective substrate is proposed.

Protection against a fungal pathogen conferred by the aphid facultative endosymbionts Rickettsia and Spiroplasma is expressed in multiple host genotypes and species and is not influenced by co-infection with another symbiont.

Many insects harbour facultative endosymbiotic bacteria, often more than one type at a time. These symbionts can have major effects on their hosts' biology, which may be modulated by the presence of other symbiont species and by the host's genetic background. We investigated these effects by transferring two sets of facultative endosymbionts (one Hamiltonella and Rickettsia, the other Hamiltonella and Spiroplasma) from naturally double-infected pea aphid hosts into five novel host genotypes of two aphid species. The symbionts were transferred either together or separately. We then measured aphid fecundity and susceptibility to an entomopathogenic fungus. The pathogen-protective phenotype conferred by the symbionts Rickettsia and Spiroplasma varied among host genotypes, but was not influenced by co-infection with Hamiltonella. Fecundity varied across single and double infections and between symbiont types, aphid genotypes and species. Some host genotypes benefit from harbouring more than one symbiont type.

Long-term clinical and radiological assessment of untreated severe cartilage damage in the knee: a natural history study.

We aimed to evaluate whether and to what extent an isolated deep cartilage lesion localized within the tibiofemoral and the patellofemoral joint has an impact on the clinical outcomes and osteoarthritis (OA) progression when it is left untreated. From 1991 to 1994, 4121 consecutive knee arthroscopies were performed, and 37 of them in patients with a single isolated chondral lesion of Outerbridge grade 4 located within weight-bearing areas of the femoral and tibial condyles (FT group) and patella (P group). The lesion size ranged from 2 to 4 cm(2) . Outcomes were reported at a mean 15.3-year follow-up using the Lysholm score, the Tegner activity scale and the Womac score. The mean Lysholm, Tegner and Womac score in the FT group was 87.7, 5.6 and 88.7, respectively. In the P group, it was 83.8, 4.8 and 84.6, respectively (P<0.0.5). Osteoarthritic changes were found in 39% of the patients. There was no difference in OA severity between an injured and an uninjured knee. In patients of the FT group, there was a relationship between the incidence of tibiofemoral OA and patellofemoral OA (P=0.00075). Severe isolated single chondral damage left with no treatment has a limited influence on clinical outcomes and the development of OA.

Isolated full thickness chondral injuries. Prevalance and outcome of treatment. A retrospective study of 5233 knee arthroscopies.

PURPOSE OF THE STUDY The aim of this study was to provide data on the prevalence and epidemiology of isolated deep chondral lesions of the knee, diagnosed in arthroscopy. The study was also aimed to analyse subjective treatment results of localized deep isolated cartilage lesions and to determine how the different factors might affect the final outcome. MATERIAL AND METHODS From 1997 to 2002, 5233 knee arthroscopies were performed. The first part of the study is an epidemiological and statistical analysis of the isolated articular cartilage lesions in which we used the questionnaire based on the International Knee Documentation Committee (IKDC) Questionnaire. The second part is the analysis of subjective treatment evaluation. For this purpose the IKDC criteria were used. Following aspects were taken into account: lesion location and size, time after surgery, patients' age, performed surgical cartilage procedure. The follow-up period ranged from 1 to 7 years. The statistical analysis was performed with the use of the Pearson correlation coefficient and t-test. Significance was set at p<0.05. RESULTS In the analyzed material cartilage lesion was diagnosed in 2931 patients (57.3%). Isolated localized chondral Outerbridge grade 3 and 4 lesions were documented in 5.2% of all patients with diagnosed cartilage lesion. The patellar articular surface (37.5%) and the medial femoral condyle (32.2%) were the most frequent localizations of these lesions. There was no correlation between the results and the period of time after arthroscopy. The best results were obtained in cases of loose body removal, debridement, mosaicplasty and also in cases where the lesion was left untreated. DISCUSSION The management of full-thickness cartilage injury remains one of the most difficult problems in the orthopedic surgery, particularly isolated and symptomatic. In 7 years of follow-up we found good and satisfactory results when debridement and loose body removal was performed and when the lesions was left untreated. Significantly the worst results in subjective evaluation we observed in marrow-stimulating procedures. This study confirms that the appropriate qualification for treatment plays the most important role in successive management of cartilage injuries. CONCLUSIONS Treatment of isolated deep chondral lesions of the knee remains a questionable issue. Little invasive arthroscopic methods as well as using no surgical treatment in grade 3 and 4 isolated cartilage lesions may be effective and improve symptoms and knee function at mid-term follow-up.Our data support also the contention that the natural history of cartilage lesions still remains unpredictable and not well understood.

Increased respiration rate as a result of adaptation to copper in confused flour beetle, Tribolium confusum Jacquelin du Val.

Multi-generation exposure of organisms to toxicants may lead to adaptations increasing their resistance to a chemical. However, the increased tolerance may have a negative effect on fitness in uncontaminated environments due to increased maintenance costs in adapted individuals. Herein we present results of a multi-generation experiment on the flour beetle, Tribolium confusum, showing that animals bred for ca. 10-13 generations in copper-contaminated medium had higher maintenance costs then their counterparts originating from uncontaminated medium. The results show that significant changes in energy budgets may occur even after relatively short selection in small laboratory cultures.