The photolytic stability of various RAFT agents (i.e., thiocarbonylthio-containing compounds) under irradiation from a blue LED light source has been investigated. The effect and implications of efficient photo-fragmentation and potential photo-degradation with regard to their performance in photopolymerization reactions is reported. The stability is found to depend strongly on the structure of the fragmenting (R-) group and the reactivity of the carbon-centered radical formed following photolytic cleavage. This is proposed to be due to the competitive rates of radical recombination and thiyl radical degradation, and has implications on the choice of monomer (as monomer propagation requires reinitiation of the oligomeric/polymeric RAFT agent). These findings can provide guidelines and increase understanding when conducting a photopolymerization employing thiocarbonylthio RAFT agents. † Electronic supplementary information (ESI) available: Materials and characterization details. Experimental procedures and supplementary figures. See
Abstract. An analysis of testicular morphology and spermatogenesis in the Heteroptera species Antiteuchus tripterus (Pentatomidae) revealed that these traits differ from that recorded for other species of the same family. The testes of A. tripterus have only six lobes, while other species of the same family typically have seven lobes, including a compound lobe, i.e., a lobe containing another in its lumen. A study of meiosis and sperm structure in the different lobes of A. tripterus revealed a conventional meiosis in the lobes numbered one to three. In lobe four, however, prophase I spermatocytes exhibit the morphological characteristics of the so called "diffuse" stage and are larger than those in lobes 1-3 in this and the remaining phases of meiosis. Thus, the resulting spermatids are not only larger but also their head is morphologically different. Lobe 5 exhibits characteristics known from other Pentatomidae species such as an uneven distribution of chromatin to the daughter cells, which give rise to cells of different sizes. This lobe forms spermatozoa of different sizes. Lobe 6, contained within lobe 5, differs from it by having larger cells at a stage similar to the so called "diffuse" and spermatid tails with cross divisions, which are not found in other lobes and unreported in the literature.
ABStrACt. Males of Limnogonus aduncus were found to have the sex chromosome system X0 and chromosome number 2n = 23 (22A + X0). Testis cells were stained with lacto-acetic orcein and silver nitrate so that changes in the morphology and degree of staining of the heteropicnotic chromatin and the nucleolar material could be observed during meiosis and spermiogenesis. These structures share the same nuclear position and could be seen until almost the end of spermiogenesis. A chromosome region stained with silver ni-
Summary Some cytogenetical aspects of spermatozoa formation were studied in 9 Coreidae Brazilian species: Anasa bellator, Athaumastus haematicus, Chariesterus armatus, Dallacoris obscura, Dallacoris pictus, Leptoglossus gonagra, Leptoglossus zonatus, Sphictyrtus fasciatus, and Zicca annulata. Similarly to the other species described to date, all the species studied herein showed cystic spermatogenesis, a reddish membrane covering the testes, a X0 sex determining system, a pair of m-chromosomes, intersticial chiasmata in most autosomes, and autosomes dividing reductionally at first meiotic division and equationally in the second 1 while sex chromosomes, divide equationally and reductionally at first and second meiotic division, respectively. In addition, it was observed that the sex chromosome is heteropycnotic at prophase and that heteropycnotic chromosomal material is found in the nuclei at spermiogenesis. In the species studied, the diploid chromosome number ranged from 19 to 25. It was 19 in S. fasciatus (16Aϩ2mϩX0); 21 in A. bellator, A. haematicus, D. obscura, D. pictus, L. gonagra, and L. zonatus (18Aϩ2mϩX0); 23 in Z. annulata (20Aϩ2mϩX0); and 25 in C. armatus (22Aϩ2mϩX0).
ABSfRAcr. NEOTROPICAL MIRIDAE. CCCXCVIII. NEW GENUS ANO SPECIES FROM SOUTH OF BRAZIL (HEMIPTERA). A new genus and five new species of Hemiptera, Miridae, from south of Brazil are described as follows: DerophthaIma vittinotata, sp.n.; Parachius paIlidus, sp.n.; Paranacoris, gen.n.; Paranacoris vertexaIbus, sp.n.; Tropidosteptes viUiscuteIlatus, sp.n.; Tupiniqui. nus aIboantennatus, sp.n. IIIustrations of habitus and male genitalia are included.
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