Linear polyethylene in a glassy phase: The value of the glass-transition temperature

Raman spectroscopy, x-ray diffraction, and thermal analysis are used to investigate the structure of linear high-density polyethylene rapidly quenched from the melt to cryogenic temperatures. All the results point to the production of a glassy phase which crystallizes when heated above 170 K.     

The hall effect in liquid semiconductors

The proper interpretation of the Hall coefficient R_H of liquid semiconductors is still an unsolved problem, and it is a particularly interesting one in view of the frequently observed discrepancy in sign with the Seebeck coefficient. We present some new data which include measurements of the Hall mobility μ_H in liquid thallium-tellurium through the composition range where the Seebeck coefficient S changes sign, and in the range where S is negative. An abrupt change in magnitude of μ_H occurs at the intrinsic composition (Tl₂Te, where S changes sign), and μ_H is observed to have an appreciable dependence on temperature only at this composition. This is consistent with transport by carriers in two bands. μ_H is lower on the Tl-rich side of Tl₂Te, and the formula n_H = 1/R_He yields a value for n_H which is ten times larger than the electron concentration inferred from the composition, assuming that electrons are derived from the Tl in excess of Tl₂Te. We review the various suggested interpretations of the Hall effect in liquid semiconductors from several points of view, and conclude that the conventional formula n = ± 1/R_He is unreliable for inferring either the sign or concentration of the carriers.     

First-language phonotactics in second-language listening

Highly proficient German users of English as a second language, and native speakers of American English, listened to nonsense sequences and responded whenever they detected an embedded English word. The responses of both groups were equivalently facilitated by preceding context that both by English and by German phonotactic constraints forced a boundary at word onset (e.g., lecture was easier to detect in moinlecture than in gorklecture, and wish in yarlwish than in plookwish). The American L1 speakers' responses were strongly facilitated, and the German listeners' responses almost as strongly facilitated, by contexts that forced a boundary in English but not in German (thrarshlecture, glarshwish). The German listeners' responses were significantly facilitated also by contexts that forced a boundary in German but not in English (moycelecture, loitwish), while L1 listeners were sensitive to acoustic boundary cues in these materials but not to the phonotactic sequences. The pattern of results suggests that proficient L2 listeners can acquire the phonotactic probabilities of an L2 and use them to good effect in segmenting continuous speech, but at the same time they may not be able to prevent interference from L1 constraints in their L2 listening.     

Frequency and form as determinants of functor sensitivity in English-acquiring infants

High-frequency functors are arguably among the earliest perceived word forms and may assist extraction of initial vocabulary items. Canadian 11- and 8-month-olds were familiarized to pseudo-nouns following either a high-frequency functor the or a low-frequency functor her versus phonetically similar mispronunciations of each, kuh and ler, and then tested for recognition of the pseudo-nouns. A preceding the (but not kuh, her, ler) facilitated extraction of the pseudo-nouns for 11-month-olds; the is thus well-specified in form for these infants. However, both the and kuh (but not her-ler) facilitated segmentation for 8-month-olds, suggesting an initial underspecified representation of high-frequency functors.     

Champion data comparison in nuclear research institutes in Europe,the U. S., and Japan

Bibliometric analysis was carried out for champion data comparisons among prestigious nuclear research institutes (PNRI) existed in Japan, the U. S., France, and Germany. The analysis was relied on database INIS (IAEA), ECD (DOE), WOS (Thomson), and SCOPUS (Elsevier). INIS is advanced, key ex-post evaluating tool for determining general research paper-based champion. Over the 30-year time span of research paper publication, the world champion among 11 PNRI is JAERI confirmed by INIS but ORNL confirmed by ECD, WOS, and SCOPUS, the latter two collected journal submitted research paper. Five years ago JAERI is the 3rd ranked institutes following ORNL and ANL. INIS database results revealed that CEA/Grenoble is the French domestic champion regarding research paper publication. Five years ago it was CEA/Saclay. Results from analytical tools used in bibliometric studies should be viewed with careful consideration to learn of any influencing factors because different characteristics exhibited by individual databases can sometimes generate conflicting bibliometric results. This was true among INIS, ECD, WOS, and SCOPUS when looking at trends especially between 5-year periods.     

Antileukemic α-pyrone derivatives from the endophytic fungus Alternaria phragmospora

Four new (1–4) and two known (5 and 6) α-pyrone derivatives have been isolated from Alternaria phragmospora, an endophytic fungus from Vinca rosea, leaves. The isolated compounds were chemically identified to be 5-butyl-4-methoxy-6-methyl-2H-pyran-2-one (1), 5-butyl-6-(hydroxymethyl)-4-methoxy-2H-pyran-2-one (2), 5-(1-hydroxybutyl)-4-methoxy-6-methyl-2H-pyran-2-one (3), 4-methoxy-6-methyl-5-(3-oxobutyl)-2H-pyran-2-one (4), 5-(2-hydroxyethyl)-4-methoxy-6-methyl-2H-pyran-2-one (5), and 5-[(2E)-but-2-en-1-yl]-4-methoxy-6-methyl-2H-pyran-2-one (6). Compounds 2 and 4 showed moderate antileukemic activities against HL60 cells with IC₅₀ values of 2.2 and 0.9 μM and against K562 cells with IC₅₀ values of 4.5 and 1.5 μM, respectively.     

Sortin1-hypersensitive mutants link vacuolar-trafficking defects and flavonoid metabolism in Arabidopsis vegetative tissues

Sortin1 is a chemical genetic-hit molecule that causes specific mislocalization of plant and yeast-soluble and membrane vacuolar markers. To better understand its mode of action, we designed a Sortin1-hypersensitive screen and identified several Sortin1-hypersensitive and flavonoid-defective mutants. Mechanistically, Sortin1 mimics the effect of the glutathione inhibitor buthionine sulfoximine and alters the vacuolar accumulation of flavonoids, likely blocking their transport through vacuole-localized ABC transporters. Structure-activity relationship studies conducted in Arabidopsis revealed the structural requirements for Sortin1 bioactivity and demonstrated that overlapping Sortin1 substructures can be used to discriminate between vacuolar-flavonoid accumulations and vacuolar-biogenesis defects. We conclude that Sortin1 is a valuable probe for dissecting novel links among flavonoid transport, vacuolar integrity, and the trafficking of vacuolar targeted cargoes in Arabidopsis.     

Spherical nucleic acids

A historical perspective of the development of spherical nucleic acid (SNA) conjugates and other three-dimensional nucleic acid nanostructures is provided. This Perspective details the synthetic methods for preparing them, followed by a discussion of their unique properties and theoretical and experimental models for understanding them. Important examples of technological advances made possible by their fundamental properties spanning the fields of chemistry, molecular diagnostics, gene regulation, medicine, and materials science are also presented.