Multiscale analysis of bamboo deformation mechanisms following NaOH treatment using X-ray and correlative microscopy.

For hundreds of years, bamboo has been employed for a variety of applications ranging from load-bearing structures to textiles. Thanks to its hierarchical structure that is functionally graded and naturally optimised, bamboo displays a variation in properties across its stem that ensures exceptional flexural performance. Often, alkaline solutions are employed for the treatment of bamboo in order to alter its natural elastic behaviour and make it suitable for particular applications. In this work we study the effect of NaOH solutions of five different concentrations (up to 25%) on the elastic properties of bamboo. By exploiting the capabilities of modern experimental techniques such as in situ synchrotron X-ray scattering and Digital Image Correlation, we present detailed analysis of the deformation mechanisms taking place in the main constituents of bamboo, i.e. fibres and matrix (Parenchyma). The principal achievement of this study is the elucidation of the deformation mechanisms at the fibre scale, where the relative sliding of fibrils plays a crucial role in the property modification of the whole bamboo stem. Furthermore, we shed light on the parenchyma toughness variation as a consequence of alkali treatments. STATEMENT OF SIGNIFICANCE: Alkaline solutions are often employed for the treatment of bamboo in order to alter its natural elastic behaviour. In this work we study the effect of alkaline solutions on the elastic properties of bamboo. Using state of the art experimental techniques allowed shedding light on the deformation mechanisms occurring in the bamboo main constituents, i.e. fibres and matrix (parenchyma cells). Enhancement of fibre stiffness was experienced when up to 20% NaOH solution was employed, while for higher concentration a decay was observed. This effect was imputed to the modification of adhesion between fibrils induced by disruption of ligand elements (e.g. lignin). Modification of the matrix toughness was also experienced, that indicated an improved resistance to cracking when the concentration of NaOH is 25%, while reduction of toughness was revealed for lower concentrations.

Effects of verapamil and adenosine in an adjunct to tirofiban on resolution and prognosis of noreflow phenomenon in patients with acute myocardial infarction.

AIM: We aimed to investigate the effects of verapamil and adenosine in an adjunct to intravenous tirofiban on management and prognosis of no-reflow phenomenon during primary percutaneous coronary intervention (PPCI) and to compare their efficacies on reversing of no-reflow phenomenon and short and midterm survival. METHODS: We included 46 patients with acute ST-segment elevation myocardial infarction (STEMI) and occurrence of no-reflow phenomenon after PPCI. All patients received intravenous tirofiban and then randomized into one of the following 3 groups: intracoronary adenosine (N.=16), intracoronary verapamil (N.=15) or placebo (N.=15). RESULTS: Intracoronary verapamil therapy had significant effect in restoring impaired coronary blood flow by decreasing thrombolysis in myocardial infarction (TIMI) frame count from 73±44 to 52±48 (P=0.024). However, adenosine and serum physiologic administration were not found to be so effective in decreasing TIMI frame count (from 81±35 to 71±46, P=0.084; from 74±32 to 71±37, P=0.612, respectively). In-hospital and 6-month survival rates were similar among groups. CONCLUSION: In conclusion, intracoronary verapamil restored the impaired coronary blood flow more effectively than adenosine or placebo. However, none of them has changed the clinical course in the first 6 months.

Genetic and geographic variation of bulbous barley (Hordeum bulbosum L.) assessed by rapd markers.

Estimated the genetic relationships among 21 barley accessions from 17 bulbous barley (H. bulbosum L.), 4 cultivated barley (H. vulgare L.) collected from different part of Turkey were investigated using Random Amplified Polymorphic DNA (RAPD). Eleven informative primers amplified 111 markers of which 98 (89.8%) were polymorphic. A dendogram was constructed using the UPGMA method based on the RAPD markers. The range of genetic similarity was from 0.111 to 0.815. The accessions were grouped into two main clusters based on the molecular data. The H. vulgare and H. bulbosum separated into two groups in the Principle Component Analysis.