Grain–boundary interactions and orientation effects on crack behavior in polycrystalline aggregates

AbstractA dislocation-density grain–boundary interaction scheme has been developed to account for the interrelated dislocation-density interactions of emission, absorption and transmission in GB regions. The GB scheme is based on slip-system compatibility, local resolved shear stresses, and immobile and mobile dislocation-density accumulation at critical GB locations. To accurately represent dislocation-density evolution, a conservation law for dislocation-densities is used to balance dislocation-density absorption, transmission and emission from the GB. The behavior of f.c.c. polycrystalline copper, with different random low and high angle GBs, are investigated for different crack lengths. For aggregates with random low angle GBs, dislocation-density transmission dominates at the GBs, which can indicate that the low angle GB will not significantly change crack growth directions. For aggregates with random high angle GBs, extensive dislocation-density absorption and pile-ups occur. The high stresses associated with this behavior, along the GBs, can result in intergranular crack growth due to potential crack nucleation sites in the GB

Comparative Toxicity of Neem and Peppermint Oils Nano Formulations against Agrotis ipsilon (Hufn.) Larvae (Lepidoptera: Noctuidae)

Applications of nanotechnology in agriculture will result in the development of efficient and potential approaches towards the management of insect pests. The toxicity effects of four essential oils peppermint, thyme, camphor and sage oils were tested against the fourth instar larvae of Agrotis ipsilon to select the most effective essential oil to be converted to the nano form. According to the results obtained, peppermint oil was the most toxic compound, which has been used in the present investigation  compared  with neem oil. The toxicity of  bulk and nano- formulations of neem  and pepper mint oils were tested  against  2nd and 4th instar  larvae of A. ipsilon under laboratory conditions of 25±2 °C& 65 -70 % R.H.relative humidity The results show that the LC50 value (the concentration used which kill 50% of the tested individuals)of loaded neem or pepper mint were lower (0.62 and 36.47 ppm) compared with neem or pepper mint oil nano-emulsion and bulk neem for the second larval instar. The different formulations of neem are more potent than in case of peppermint oil, as LC50 and LC90 values were significantly lower.The same trend was found concerning the 4th larval instar. Age of treated larvae had a detrimental effect on the response to the compounds tested. It was noticed that the younger larvae were much more sensitive to the prepared compounds compared to the older ones. The least LC50 value for loaded neem nano-emulsion was 6.68 ppm compared with the highest value for  bulk neem oil (16.68 ppm ). Also,  LC90  values followed the same trend as in  case ofLC50.  Again, the toxicity of loaded peppermint oil had the most insecticidal activity as expressed by the lowest LC50 value (51.9 ppm) with more insecticidal effect than the bulk(125.43 ppm)  or nano-emulsion (85.43 ppm).  The present results indicated that these novel systems could be used in integrated pest management program for A. ipsilon control

Comparative Toxicity of Neem and Peppermint Oils Nano Formulations against Agrotis ipsilon (Hufn.) Larvae (Lepidoptera: Noctuidae)

Applications of nanotechnology in agriculture will result in the development of efficient and potential approaches towards the management of insect pests. The toxicity effects of four essential oils peppermint, thyme, camphor and sage oils were tested against the fourth instar larvae of Agrotis ipsilon to select the most effective essential oil to be converted to the nano form. According to the results obtained, peppermint oil was the most toxic compound, which has been used in the present investigation  compared  with neem oil. The toxicity of  bulk and nano- formulations of neem  and pepper mint oils were tested  against  2nd and 4th instar  larvae of A. ipsilon under laboratory conditions of 25±2 °C& 65 -70 % R.H.relative humidity The results show that the LC50 value (the concentration used which kill 50% of the tested individuals)of loaded neem or pepper mint were lower (0.62 and 36.47 ppm) compared with neem or pepper mint oil nano-emulsion and bulk neem for the second larval instar. The different formulations of neem are more potent than in case of peppermint oil, as LC50 and LC90 values were significantly lower.The same trend was found concerning the 4th larval instar. Age of treated larvae had a detrimental effect on the response to the compounds tested. It was noticed that the younger larvae were much more sensitive to the prepared compounds compared to the older ones. The least LC50 value for loaded neem nano-emulsion was 6.68 ppm compared with the highest value for  bulk neem oil (16.68 ppm ). Also,  LC90  values followed the same trend as in  case ofLC50.  Again, the toxicity of loaded peppermint oil had the most insecticidal activity as expressed by the lowest LC50 value (51.9 ppm) with more insecticidal effect than the bulk(125.43 ppm)  or nano-emulsion (85.43 ppm).  The present results indicated that these novel systems could be used in integrated pest management program for A. ipsilon control

Inheritance of OCT4 predetermines fate choice in human embryonic stem cells

It is well known that clonal cells can make different fate decisions, but it is unclear whether these decisions are determined during, or before, a cell's own lifetime. Here, we engineered an endogenous fluorescent reporter for the pluripotency factor OCT4 to study the timing of differentiation decisions in human embryonic stem cells. By tracking single-cell OCT4 levels over multiple cell cycle generations, we found that the decision to differentiate is largely determined before the differentiation stimulus is presented and can be predicted by a cell's preexisting OCT4 signaling patterns. We further quantified how maternal OCT4 levels were transmitted to, and distributed between, daughter cells. As mother cells underwent division, newly established OCT4 levels in daughter cells rapidly became more predictive of final OCT4 expression status. These results imply that the choice between developmental cell fates can be largely predetermined at the time of cell birth through inheritance of a pluripotency factor

Pengantar Hukum Acara Pidana Di Indonesia

x, 388 hlm, 16x23 c

Pengantar hukum acara pidana di Indonesia

x.; 387 hal.; ill.; 19 c