Poly(N-vinylimidazole)-l-poly(propylene glycol) amphiphilic conetworks and gels: molecularly forced blends of incompatible polymers with single glass transition temperatures of unusual dependence on the composition

New molecularly forced blends of incompatible poly(N-vinylimidazole) and poly(propylene glycol) polymers with single glass transition temperatures.</p

Fracture behavior of boehmite-filled polypropylene block copolymer nanocomposites as assessed by the essential work of fracture concept

The essential work of fracture (EWF) method was adapted to determine the fracture toughness of poly(propylene-block-ethylene) (EPBC) based nanocomposites with different amounts (from 0 up to 5 wt.%) of synthetic boehmite alumina (BA). The dispersion of BA in the matrix was studied by transmission and scanning electron microscopies. Agglomerated micronscale along with well dispersed nanoscale BA particles were present in the EPBC matrix. By contrast to the neat EPBC, all nanocomposites failed by unstable necking. Therefore the energy partitioning concept of the EWF was adapted and attention paid to the yielding-related term. Both specific yielding-related essential and non-essential work of fracture parameters increased linearly with the product of the yield stress and elongation at yield derived from static tensile tests

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Laser Ablation on Isostatic Graphite&mdash;A New Way to Create Exfoliated Graphite

In search of a new way to fabricate graphene-like materials, isostatic graphite targets were ablated using high peak power with a nanosecond-pulsed infrared laser. We conducted dry ablations in an argon atmosphere and liquid-phase ablations in the presence of a liquid medium (water or toluene). After the dry ablation, the SEM images of the target showed carbon in the form of a volcano-like grain structure, which seemed to be the result of liquid carbon ejected from the ablation center. No graphite exfoliation could be achieved using dry ablation. When using liquid phase ablation with water or toluene as a liquid medium, no traces of the formation of liquid carbon were found, but cleaner and deeper craters were observed. In particular, when using toluene as a liquid medium, typical graphite exfoliation was found. We believe that due to the extremely high pressure and high temperature induced by the laser pulses, toluene was able to intercalate into the graphite layers. Between the laser pulses, the intercalated toluene was able to flash evaporate and blow-up the graphite, which resulted in exfoliated graphite. Exfoliated graphite was found on the ablated graphite surface, as well as in the toluene medium. The ablation experiments with toluene undertaken in this study demonstrated an effective method of producing micrometer-sized graphene material. When using water as a liquid medium, no massive graphite exfoliation was observed. This meant that under the used laser conditions, toluene was a better intercalant for graphite exfoliation than water