Helicity Control of Polymeric Backbones with Alternating cis-trans Double Bonds in Cyclopolymerized Dipropargyl Amides.

We report the synthesis of new helical polymeric structures having alternating cis and trans double bonds and chiral amino acid side chains by metathesis cyclopolymerization. The polymer helicity, which is generated by the interaction between fluorenylmethyloxycarbonyl (Fmoc) groups in the side chains, is dramatically affected by solvents. A thorough experimental and theoretical analysis including nuclear magnetic resonance, atomic force microscopy, and density functional theory and molecular mechanics calculations suggests that the helicity of both backbone and side chains are determined by anti-syn rotation of the carbamate groups and by the different interactions of the Fmoc groups with solvents.

Borderline to Moderate Blepharoptosis Correction Using Retrotarsal Tucking of Müller Muscle: Levator Aponeurosis in Asian Eyelids.

BACKGROUND: The purpose of this paper is to report the outcome of retrotarsal tucking of Müller muscle-levator aponeurosis for the correction of borderline to moderate ptosis in conjunction with esthetic blepharoplasty in Asian eyelids and to explore the relationship between the extent of advancement and change in the eyelid position (MRD1). METHODS: The medical records of 290 consecutive patients who underwent retrotarsal tucking of Müller muscle-levator aponeurosis from February 2005 to November 2011 were reviewed. Of those, 26 patients (51 eyelids) were statistically analyzed. The correction was performed through an external upper blepharoplasty approach. Once the orbital septum was opened, the Müller muscle-levator aponeurosis was advanced and tucked under the posterior surface of the tarsus by a single lifting suture. The average follow-up period was 20.6 months, with a range of 3-68 months. RESULTS: In 26 patients (51 eyelids), satisfactory results were recorded for 49 of 51 eyelids (96.1 %). The margin reflex distance-1 (MRD1) increased from 1.56 ± 0.70 mm preoperatively to 3.86 ± 0.94 mm postoperatively (p < 0.001, Wilcoxon signed rank test). When 6.1 mm of advancement was implemented, an average MRD1 of 1 mm was achieved. For 7.2 and 8.3 mm of advancement, the average MRD1 achieved was 2 and 3 mm each. A noteworthy complication, although not included in statistical analysis, was one patient who had developed corneal irritation caused by the conjunctival exposure to the non-absorbable suture 3 years after the surgery, which led the subject to have the suture removed. CONCLUSION: The author concludes that this procedure is one of the most effective surgical options in correcting borderline to moderate blepharoptosis in conjunction with esthetic blepharoplasty. The main advantage of such a method is that once the orbital septum is opened, Müller muscle-levator aponeurosis is easily advanced and tucked under the posterior surface of the tarsal plate without extensive dissection or resection, which is less traumatic and gives a more vertical lifting vector, thus producing excellent cosmetic results and quick recovery.

Single-stage reconstruction of skin-involving nasal paraffinoma with pericraniosubgaleal flap.

BACKGROUND: The removal of a paraffinoma over the nasal bridge may result in thinning and even loss of involved skin as well as a saddle nose deformity. For nasal reconstruction, a variety of techniques using a free graft of autogenous tissue such as fascia, dermofat, or cartilage have been used, either in immediate, single-stage or in delayed, multiphase treatment. However, such reconstructions can be challenging largely due to absorption of the grafted tissue and poor blood supply to the surrounding nasal tissue infiltrated with paraffin. This article reports the successful clinical outcomes of immediate, single-stage reconstructions by wrapping a pericraniosubgaleal flap over the nasal implant after removing a paraffinoma. METHODS: Eleven patients with a paraffinoma showing a palpable lump, redness, or telangiectasia over the nasal skin were treated between November 1998 and March 2011. The mean follow-up period was 20.1 months. As much of the paraffinoma as possible was removed via a bidirectional approach (open rhinoplasty and frontal hairline incision), and the resulting deformity was reconstructed simultaneously using a pericraniosubgaleal flap and turning it over the sculpted nasal implant (ePTFE; GORE-TEX(®) in nine cases and silicone in two cases). RESULTS: Nine patients (81.8%) were treated successfully without complications and were satisfied with their results. However, the other two patients complained of incomplete removal of the paraffinoma requiring additional removal. Telangiectasia over the nose improved in four out of six patients after surgery. CONCLUSION: Nasal reconstruction using a pericraniosubgaleal flap is one of the most reliable surgical options for treating skin-involving nasal paraffinomas. The advantage of such a method is that a well-vascularized and durable flap, which is resistant to infection, is wrapped over the sculpted nasal implant in a single step. It also reinforces the thinned skin, which makes it easier to form various shapes, producing excellent cosmetic results. Finally, it can also serve as a tolerable graft bed in the case of overlying skin loss.

De novo generation of a bright blue fluorophore from 2-oxoglutarate in biological samples.

We discovered the generation of a new bright blue fluorophore from a particular type of amine and 2-oxoglutarate (2-OG) under mild conditions without any chemical additives. Two ß-aminoethylamine molecules and three 2-OG molecules form an unprecedented 2-pyridone structure with a fused γ-lactam ring (DTPP) via complex reactions including double decarboxylation and quintuple dehydration. The DTPP fluorophore shows a high quantum yield (80%) and photostability. The great potential of the present DTPP generation in the quantitative analysis of 2-OG in biosamples is demonstrated.

Self-organization of amphiphilic polymer in vesicle bilayers composed of surfactant mixtures.

Cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron scattering (SANS) are used to investigate the association of amphiphilic polymers consisting of a double-chain hydrophobic tail attached onto poly(ethylene glycol) (PEG) polymer chains into two different systems of equilibrium vesicles. For cetyltrimethylammonium bromide (CTAB)/sodium perfluorohexanoate (FC(5)) vesicle bilayers, the size distribution of the vesicles slightly becomes narrow in the presence of the polymers, suggesting that the wedge-shaped polymers increase the spontaneous curvature of the vesicles. In contrast, the confinement of polymer molecules inside the CTAB/sodium perfluorooctanoate (FC(7)) vesicles that are stabilized by spontaneous curvature causes an abrupt decrease in the bilayer rigidity. By an analysis of vesicle size distribution, it is found that the membrane elasticity of CTAB/FC(7) vesicles is varied considerably from 6k(B)T to 0.3k(B)T, implying the transition of stabilization mechanism from spontaneous curvature to thermal fluctuation in the presence of polymer. The polymer incorporation mechanism into the bilayers is understood, in the comparison of the vesicle radius and size distribution before and after adding polymer, as that the polymer is anchored into the vesicle bilayer owing to hydrophobic property after the adsorption on the surface of the bilayer.