Hybrid fluorescent liquid crystalline composites: directed assembly of quantum dots in liquid crystalline block copolymer matrices

Hybrid fluorescent liquid crystalline (LC) composites containing inorganic quantum dots (QDs) are promising materials for many applications in optics, nanophotonics and display technology, combining the superior emission capability of QDs with the externally controllable optical properties of LCs. In this work, we propose the hybrid LC composites that were obtained by embedding CdSe/ZnS QDs into a series of host LC block copolymers of different architectures by means of a two-stage ligand exchange procedure. The ABA/BAB triblock copolymers and AB diblock copolymers with different polymerization degrees are composed of nematogenic phenyl benzoate acrylic monomer units and poly(4-vinylpyridine) blocks, which are capable of binding to the QD surface. Our results clearly show that the spatial distribution of QDs within composite films as well as the formation of QD aggregates can be programed by varying the structure of the host block copolymer. The obtained composites form a nematic LC phase, with isotropization temperatures being close to those of the initial host block copolymers. In addition, the influence of the molecular architecture of the host block copolymers on fluorescence properties of the obtained composites is considered. The described strategy for the QD assembly should provide a robust and conventional route for the design of highly ordered hierarchical hybrid materials for many practical applications.

Spatial distribution of QDs within hybrid composite films was programed by varying the molecular architecture of the host LC block copolymers.     

Bilateral adrenal cysts and ectopic pancreatic tissue in Beckwith-Wiedemann syndrome: is a conservative approach acceptable?

Beckwith-Wiedemann syndrome is a common overgrowth syndrome associated with an increased risk of neoplasias which might be explained by the nature and localization of the genetic defect. While malignant tumors are often associated with hemihypertrophy, benign tumors are also found. We report a patient with the typical features of Beckwith-Wiedemann syndrome with two histologically different abdominal tumors, bilateral cystic adrenals and ectopic pancreatic tissue present at birth. In both tumors no malignancy could be detected. Ectopic pancreatic tissue is rarely seen and has been described in Beckwith-Wiedemann syndrome only once. After extirpation of the ectopic pancreatic tissue the cystic adrenals were left in situ since macroscopically no normal adrenal tissue could be identified and separated. Regular ultrasound examinations revealed complete resolution of the cystic adrenals within 24 months. Thus it seems that a conservative approach in selected tumors associated with the Beckwith-Wiedemann syndrome might be acceptable.     

Microtest systems in the diagnosis of cholera

Micro test systems for the biochemical identification of comma bacilli (MTS-V) and for a rapid determination of their groups according Heiberg (MTS-H) were designed and commissioned into medical practice. The micro test systems showed their advantages before the control media of Hiss and Bacterium Incubation Media at studying the museum-kept and freely-obtained vibrio strains as well as at studying the concomitant microflora and clinical materials taken from ill people and vibrio-carriers during the 1994 outbreak of cholera in Daghestan.     

Isolation of mycobacteria L forms as a prognostic criterion of recurrence and aggravation of tuberculosis in patients with extended residual tuberculous lesions of the lungs

To elucidate the role of tubercle bacilli L-forms in tuberculosis relapsing and aggravation in patients with extended residual lesions in the lungs, 117 patients mainly with extended and neglected destructive tuberculosis of the lungs were observed for a period of 5 to 7 years with using microbiological and clinico-roentgeno-laboratory examinations. Analysis of the immediate and remote results of the treatment showed that in the group of the abacillary patients according to the routine microbiological investigations who continued to isolate L-forms of tubercle bacilli at the background of remaining destructive cavities in the lungs aggravations and relapses amounted to 46.6 per cent. The etiological role of the L-forms was proved by absolute identity of the biological properties of the L-form revertants isolated from in vitro subcultures and tubercle bacilli, isolated from the patients during the process relapsing.     

Adult tonsillectomy and day care surgery

Objective

To evaluate the safety of adult tonsillectomy as a day care surgery

Methods

Records of 664 patients above the age of 12 years, who underwent tonsillectomy were analysed. These patients were operated in our department within January 1999 and September 2002. Only 13 patients (1.95%) had post operative bleeding and were readmitted after discharge. The data of these patients were collected from medical records as well from the morbidity meeting proceedings and was reviewed retrospectively. Statistical analysis was done by using ‘one sample t-test’.

Results

Overall incidence of post operative bleeding was 1.95%. None of our pateients bled with 12 hours of Surgery, 0.3% had bleeding between 12 to 24 hours after tonsillectomy and 1.65% encountered bleeding between 24 hours to the 6th post operative day. Bleeding was not major in majority of patients as only 0.45% of the patients required second anesthesia to control the bleeding and only 0.35% of patients required blood transfusion to replace the lost blood volume. In addition, higher incidence of bleeding was seen in males, in the older age group of 31–40 years, patients with obstructive sleep aponea and in patients where tonsillectomy was done by electrocautry dissection.

Conclusion

Based on these observations, we conclude that Adult tonsillectomy can be safely preformed in our setup.