Self-assembly of p-tert-butyl thiacalix[4]arenes and metal cations into nanoscale three-dimensional particles

The shape of supramolecular aggregates based on stereoisomers of p-tert-butyl thiacalix[4]arenes functionalized with secondary, tertiary amide and hydrazide groups at the lower rim in cone, partial cone and 1,3-alternate conformations with several metal cations were investigated by atomic force microscopy. The examined p-tert-butyl thiacalix[4]arenes form host-guest complexes; dimers, spherics ellipsoids and elongated nanoscale particles depending on the conformation of macrocycles, the nature of the binding centers and the nature of the metal cation. Only associates formed by p-tert-butyl thiacalix[4]arenes with morpholide groups at the lower rim in cone conformation with silver cations exhibited a higher antimicrobial activity. Copyright © 2012 John Wiley & Sons, Ltd

Zenlens scleral lenses for visual rehabilitation of patients with irregular cornea: a usage experience

Scleral lenses improve visual acuity in patients with irregular corneal astigmatism, which is especially important when other methods of correction are ineffective.Purpose: to assess the efficiency of Zenlens scleral lenses in patients with irregular cornea.Material and methods. A total of 120 patients (164 eyes) were examined, including 86 males and 34 females, aged from 13 to 63 years (mean age 35 ± 12 years). The patients were divided into 4 groups. Group 1 consisted of patients with keratoconus, group 2 — postpenetrating keratoplasty, group 3 — keratoconus after cross-linking and/or corneal ring segment implantation, while group 4 consisted of patients with other diseases. The efficiency criteria included visual acuity before and after scleral lens fitting and wearing time (hours per day). To determine social significance of scleral lens wearing, we selected 30 patients (46 eyes) with average best-corrected visual acuity (BCVA) before fitting 0.21 ± 0.08 (0.1–0.3).Results. Average uncorrected visual acuity before fitting did not exceed 0.2 and average visual acuity after fitting was 0.8 ± 0.15. Average improvement in visual acuity after fitting compared to uncorrected visual acuity was at least six lines in all groups and average improvement of visual acuity was approximately three lines compared to BCVA before fitting. 74.4 % and 19.5 % of patients demonstrated long-term (> 10 hours per day) and partial (8–10 hours per day) wear, respectively. Short-term wear (< 8 hours per day) was noted in 6.1 % of patients. Visual acuity of  patients with low BCVA (mean 0.21 ± 0.08) increased by 0.57 (271.4 %).Conclusion. Scleral lenses can be successfully used for visual acuity improvement and social rehabilitation of patients with irregular cornea when other methods of correction are ineffective

Self-assembly of p-tert-butyl thiacalix[4]arenes and metal cations into nanoscale three-dimensional particles

The shape of supramolecular aggregates based on stereoisomers of p-tert-butyl thiacalix[4]arenes functionalized with secondary, tertiary amide and hydrazide groups at the lower rim in cone, partial cone and 1,3-alternate conformations with several metal cations were investigated by atomic force microscopy. The examined p-tert-butyl thiacalix[4]arenes form host-guest complexes; dimers, spherics ellipsoids and elongated nanoscale particles depending on the conformation of macrocycles, the nature of the binding centers and the nature of the metal cation. Only associates formed by p-tert-butyl thiacalix[4]arenes with morpholide groups at the lower rim in cone conformation with silver cations exhibited a higher antimicrobial activity. Copyright © 2012 John Wiley & Sons, Ltd

Self-assembly of p-tert-butyl thiacalix[4]arenes and metal cations into nanoscale three-dimensional particles

The shape of supramolecular aggregates based on stereoisomers of p-tert-butyl thiacalix[4]arenes functionalized with secondary, tertiary amide and hydrazide groups at the lower rim in cone, partial cone and 1,3-alternate conformations with several metal cations were investigated by atomic force microscopy. The examined p-tert-butyl thiacalix[4]arenes form host-guest complexes; dimers, spherics ellipsoids and elongated nanoscale particles depending on the conformation of macrocycles, the nature of the binding centers and the nature of the metal cation. Only associates formed by p-tert-butyl thiacalix[4]arenes with morpholide groups at the lower rim in cone conformation with silver cations exhibited a higher antimicrobial activity. Copyright © 2012 John Wiley & Sons, Ltd

Optogenetic and Chemical Induction Systems for Regulation of Transgene Expression in Plants: Use in Basic and Applied Research

Continuous and ubiquitous expression of foreign genes sometimes results in harmful effects on the growth, development and metabolic activities of plants. Tissue-specific promoters help to overcome this disadvantage, but do not allow one to precisely control transgene expression over time. Thus, inducible transgene expression systems have obvious benefits. In plants, transcriptional regulation is usually driven by chemical agents under the control of chemically-inducible promoters. These systems are diverse, but usually contain two elements, the chimeric transcription factor and the reporter gene. The commonly used chemically-induced expression systems are tetracycline-, steroid-, insecticide-, copper-, and ethanol-regulated. Unlike chemical-inducible systems, optogenetic tools enable spatiotemporal, quantitative and reversible control over transgene expression with light, overcoming limitations of chemically-inducible systems. This review updates and summarizes optogenetic and chemical induction methods of transgene expression used in basic plant research and discusses their potential in field applications

Self-assembly of p-tert-butyl thiacalix[4]arenes and metal cations into nanoscale three-dimensional particles

The shape of supramolecular aggregates based on stereoisomers of p-tert-butyl thiacalix[4]arenes functionalized with secondary, tertiary amide and hydrazide groups at the lower rim in cone, partial cone and 1,3-alternate conformations with several metal cations were investigated by atomic force microscopy. The examined p-tert-butyl thiacalix[4]arenes form host-guest complexes; dimers, spherics ellipsoids and elongated nanoscale particles depending on the conformation of macrocycles, the nature of the binding centers and the nature of the metal cation. Only associates formed by p-tert-butyl thiacalix[4]arenes with morpholide groups at the lower rim in cone conformation with silver cations exhibited a higher antimicrobial activity. Copyright © 2012 John Wiley & Sons, Ltd