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Time-resolved chemically induced dynamic nuclear polarization (TR-CIDNP) is applied to follow transformation of the short-lived neutral guanine radical into a secondary guanine radical by its protonation, presumably at position N7. In the initial step the photoreaction of guanosine-5'-monophosphate (GMP) with triplet excited 3,3',4,4'-tetracarboxy benzophenone (TCBP) leads to formation of the neutral radical G(-H). . The evidence of the radical conversion is based on the inversion of CIDNP sign for TCBP and GMP protons on the microsecond timescale as a result of the change in magnetic resonance parameters in the pairs of TCBP and GMP radicals due to structural changes of the GMP radical. Acceleration of the CIDNP sign change upon addition of phosphate (proton donor) confirms that the radical transformation responsible for the observed CIDNP kinetics is protonation of the neutral guanine radical with formation of the newly characterized cation radical, (G.+ )'. From the full analysis of the pH-dependent CIDNP kinetics, the protonation and deprotonation behaviour is quantitatively characterized, giving pKa =8.0±0.2 of the cation radical (G.+ )'.

Background Outcomes following transition can be poor; many young adults are ill prepared to take responsibility for their health care, older adolescents report incomplete understanding of medications, and parents remain largely responsible for their care. Good patient–provider relationships are associated with better adherence; however, the role of the relationship between post-transition patients and their providers has not been explored. The current study aimed to understand transition of young adults with inflammatory bowel diseases (IBD), the impact of the paediatric patient–provider relationship and what determines the adult patient–provider relationship. Methods This study examined the experience of young adults with Crohn's disease or ulcerative colitis (aged 18–30) after transition. Twenty-nine patients completed a 31-item online survey of their transition experience from paediatric to adult care. Responses were coded quantitatively and qualitatively, and qualitative responses were analysed by two independent raters. Results Positive themes regarding adult providers included independence, autonomy and trust, while negative themes included initial discomfort and confusing logistics. Five of six patients who reported ‘terrifying’ first visit experiences with their adult providers reported overall positive relationships. The earlier the diagnosis age, the less involved in medical decisions they were as an adult (r = 0.41, P = .03). Those who had a more positive experience with their paediatric providers were more likely to bring up confusion with their adult providers (r = .45, P = .04), and those who had a more positive experience with their adult providers were more likely to endorse collaborative medical decision-making (r = .57, P < .001). Conclusions Patients diagnosed with IBD at a young age may need extra education and self-management strategies, as they were less likely to exhibit behaviours indicative of a successful transition to adult care. Additionally, transition programme development may benefit from the post-transition perspective across chronic illness populations.

The theory of kinetics of polynucleotide synthesis at oligomeric templates is developed. It is shown that the dependence of oligomer efficacy on its size cannot be explained without taking into account the probability of separation of the oligomer from the growing chain. If such a possibility exists, the maximal size which can be achieved by the growing chain is determined by the ratio of the probability of proposed propagation and of the probability of separation. Without any models of the separation mechanism, the study of experimental kinetic data shows that two such mechanisms exist. Very short oligomers can be easily separated from the growing chain, but there is a critical size of oligomer after which the probability of separation is much smaller. The oligomers whose size is equal to or greater than the critical one form helices with growing chains.

A B S TR A C T In wheat, lateral (branch) roots originate always in the pericycle of the parent root between protoxylem poles of 2 successive xylem ridges and facing a sieve tube. Although the endodermis also contributes to the initial lateral protuberance when lateral root primordia develop close to the parent root apex, the pericycle alone gives rise to the lateral root which subsequently develops. Before initiation of lateral root primordia the pericycle and endodermis are each uniseriate. The first cell divisions that are characteristic of the initiation of lateral root primordia are periclinal divisions in the pericycle. When wheat is germinated and grown on colchicine, mitosis is not completed and hence no nuclear and cell divisions occur (i.e., "c-mitoses," but no true mitoses, occur). Within the primary roots of these seedlings appear structures, here called "primordiomorphs," having the shape of lateral root primordia. Each primordiomorph, which develops without cell division, is a radial protuberance in the pericycle accompanied by an associated protuberance of the adjacent endodermis. Primordiomorphs are found only between protoxylem poles of 2 successive xylem ridges and facing a sieve tube. In primordiomorphs some nuclei repeatedly enter, but none complete, mitosis. The primordiomorphs become large enough to compress the cortical parenchyma and make bulges in the epidermis of the parent root. In typical lateral root primordia comparable in size with primordiomorphs, hundreds of cell divisions have occurred that are absent in the primordiomorphs. After removal of colchicine the primordiomorphs develop with normal cell divisions into polyploid lateral roots as shown by the following findings: (1) Stages of development are detected that are intermediate between primordiomorphs and polyploid lateral roots with typical histological organization. As in normal lateral root initiation close to the parent root apex, the endodermis contributes to the initial protuberance but the pericycle alone gives rise to the lateral root which subsequently develops. (2) The number of these polyploid lateral roots formed can be accounted for by the number of primordiomorphs which disappear. (3) No "c-mitoses" occur, i.e., the diploid and polyploid nuclei undergo only normal mitoses. Thus, primordiomorphs have 2 definitive morphological characteristics of typical lateral root primordia, viz.: (1) precise identity of histological site of origin, and (2) potentiality (realized after removal of colchicine) to develop into roots having typical histological organization. It is, therefore, concluded that primordiomorphs are lateral root primordia that developed without completion of mitosis and without cytokinesis. Since the parent root pericycle remains uniseriate, even in that region which comprises the primordiomorph, no periclinal cell divisions within the pericycle could have altered the polarization of growth to set iip the apical-basal axis of the primordiomorph. These results demonstrate that the earliest detectable changes in form involved in the initiation of a lateral root primordium can occur without completion of any mitosis and without anv evtokine. is