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The effect of acid concentration on the conversion between three distinct optical species, spiropyran (SP), merocyanine (MC) and MC-[OH.sup.+], are examined through spectrophotometric and NMR studies. The study shows that the acidochromic rate of conversion between SP and MC-[OH.sup.+] is inversely proportional to the concentration of acid present in the media.

The article reviews the exhibition "Icons of American Animation," which spoke on the rich history of animation considered as one of the most popular and influential art forms.

The atropisomeric dopant 2,2',6,6'-tetramethyl-3,3'-dinitro-4,4'-bis[4-nonyloxybenzoyl)oxy]biphenyl (1) induces a ferroelectric SmC* phase when doped into the SmC liquid crystal hosts2-(4-butyloxyphenyl)-5-octyloxypyrimidine (PhP1) and (plusmn)-4-[(4-methylhexyl)oxyl]phenyl 4-decyloxybenzoate (PhB). The results obtained using the atropisomeric dopant as probe suggest that the chiral perturbation exerted by 2,2',6,6'-tetramethyl-3,3'-dinitro-4,4'-bis[4-nonyloxybenzoyl)oxy]biphenyl can amplify the polarization power of another atropisomeric dopant.

Thermal racemization is examined with reference to a series of six substituted indolinobenzospiropyrans. The results of this study which show competition between the polar and nonpolar mechanisms are presented.

A study synthesized in optically pure form 11 chiral, atropisomeric dopants and measured their polarization power in five sC liquid crystal hosts representing four distinct structural classes of mesogens. It is argued that polarization amplification occurs through a feedback mechanism where intercore chirality transfer leads to an asymmetric distortion of the ferroelectric sC lattice. This in turn further increases the conformational asymmetry of the atropisomeric dopant.

Research was conducted to examine the role of dispersion and electrostatic forces on solute-solvent interactions in a nematic liquid crystal phase. A series of 23 substituted biphenyl, phenylpyridine and bipyridine derivatives were doped in the nematic liquid crystal host. Results indicated that charge-transfer complexation and molecular dipole-dipole interactions do not have a significant effect on the stability of arene-arene interactions in the nematic phase.

A novel chiral dopant is synthesized in 11 steps from 4,4'-dihydroxy-2,2'-dimethyl-6,6'-dinitrobiphenyl to give 9% yield. It induces a ferroelectric Sc* phase in two Sc liquid crystal hosts via spontaneous polarization. It induces positive polarization in the presence of cyclohexanecarbonitriles and negative polarization in the presence of phenyl benzoate. The polarization power of the dopant is dependent on the nature of the Sc host.

A molecular orbital computational study was carried out on cis-1,3-diarylcyclohexanes to quantify pi-stacking of the aromatic rings from the corformational equilibria shifts. The calculations from Hammett correlations, electrostatic potentials, and molecular orbital energy gaps conformed with experimental results. Arene-arene pi-stacking is governed more by electrostatic than charge-transfer interactions. The closest correlation is detected on the pi-face of individual component arenes by electrostatic potentials measured from the electron density surface.

Smectic liquid crystals with a low layer contraction of less than 1% upon an SmA to SmC transition are referred to as 'de Vries-like'. These materials have attracted considerable attention as possible alternative to problems with surface-stabilized ferroelectric liquid crystals in liquid crystal displays. The 'de Vries-like' properties of liquid crystals with nanosegregating carbosilane segments are enhanced by lengthening the carbosilane end-groups from mono- to tricarbosilane. The observed enhancement is thought to arise from an increase in the cross-section of the free volume in the hydrocarbon sub-layer. The hypothesis is tested by assuming that dimers with a tricarbosilane linking group have smaller time-averaged cross-sections. This paper reports the synthesis and characterization of two homologous series of liquid crystals and an investigation of their mesogenic properties as model systems employing liquid crystalline monomers (QL39-n) and dimers (QL40-n) comprising 2-phenylpyrimidine cores and tricarbosilane end-groups and spacers, respectively. We find that the QL39-n monomers form only a tilted SmC phase, whereas the QL40-n dimer forms an orthogonal SmA phase due to the tricarbosilane spacer will not have a spherically shape on the time average like that predicted for the tricarbosilane end-group. Results are discussed in the context of the timeaveraged cross-sections of the materials. [ABSTRACT FROM AUTHOR]

The synthesis of axially chiral (arylmethylene)cycloalkenes in their racemic and enantiomeric forms leads to a study of their use in optical switches. Theirirradiation with UV light leads to double-bond isomerization and to racemization, but sometimes to destruction of both enantiomers. The use of the chiral exciton coupling model allows these monochromophoric compounds to exhibit enough anisotropy induce cholesteric behavior upon addition to nematic crystals. Other results of this evaluation and their implications are discussed.

Abstract Background The purpose of this study was to compare the effects of supplementation with Gaspari Nutrition's SOmaxP Maximum Performance™ (SOmaxP) versus a comparator product (CP) containing an equal amount of creatine (4 g), carbohydrate (39 g maltodextrin), and protein (7 g whey protein hydrolysate) on muscular strength, muscular endurance, and body composition during nine weeks of intense resistance training. Methods Using a prospective, randomized, double-blind design, 20 healthy men (mean ± SD age, height, weight, % body fat: 22.9 ± 2.6 y, 178.4 ± 5.7 cm, 80.5 ± 6.6 kg, 16.6 ± 4.0%) were matched for age, body weight, resistance training history, bench press strength, bench press endurance, and percent body fat and then randomly assigned via the ABBA procedure to ingest 1/2 scoop (dissolved in 15 oz water) of SOmaxP or CP prior to, and another 1/2 scoop (dissolved in 15 oz water) during resistance exercise. Body composition (DEXA), muscular performance (1-RM bench press and repetitions to failure [RTF: 3 sets × baseline body weight, 60-sec rest between sets]), and clinical blood chemistries were measured at baseline and after nine weeks of supplementation and training. Subjects were required to maintain their normal dietary habits and follow a specific, progressive overload resistance training program (4-days/wk, upper body/lower body split) during the study. An intent-to-treat approach was used and data were analyzed via ANCOVA using baseline values as the covariate. Statistical significance was set a priori at p ≤ 0.05. Results When adjusted for initial differences, significant between group post-test means were noted in: 1-RM bench press (SOmaxP: 133.3 ± 1.3 kg [19.8% increase] vs. CP: 128.5 ± 1.3 kg [15.3% increase]; p < 0.019); lean mass (SOmaxP: 64.1 ± 0.4 kg [2.4% increase] vs. 62.8 ± 0.4 kg [0.27% increase], p < 0.049); RTF (SOmaxP: 33.3 ± 1.1 reps [44.8% increase] vs. 27.8 ± 1.1 reps [20.9% increase], p < 0.004); and fat mass (SOmaxP: 12.06 ± 0.53 kg [9.8% decrease] vs. 13.90 ± 0.53 kg [4.1% increase], p < 0.024). No statistically significant differences in vital signs (heart rate, systolic and diastolic blood pressures) or clinical blood chemistries were noted. Conclusions These data indicate that compared to CP, SOmaxP administration augments and increases gains in lean mass, bench press strength, and muscular performance during nine weeks of intense resistance training. Studies designed to confirm these results and clarify the molecular mechanisms by which SOmaxP exerts the observed salutary effects have begun. Both SOmaxP and the CP were well-tolerated, and no supplement safety issues were identified.

The article explains the design, synthesis and characterization of two different series of liquid crystals with 'de Vries-like' properties. The frustration observed between the elements promoting SmA and SmC phases is also discussed.

A new approach is described where in the axially chiral monomers are employed for the synthesis of the chiral periodic mesoporous organosilicates. These materials are shown to be widely used in various applications, including the catalysis and separation science.

Various routes are examined for the synthesis of chiral biphenyl species that are substituted at the 2,2', 4,4' and 6,6' positions. An Ullmann coupling is employed on a dibrominated arene, which has occurred selectively at the more hindered bromine by virtue of the directing effect of an ortho ester substituent.

The axially chiral dopants (R)-5,5'-5,6'- and 6,6'-diheptyloxy-2,2'-spirobiindan-1,2'-dione were synthesized in optically pure form, and their absolute configurations were assigned by the exciton chirality method using circular dichroism spectroscopy. The new compounds were doped in four achiral liquid crystal hosts to give chiral smectic C* phases with spontaneous polarizations that vary with the core structure of the host.

The synthesis and characterization of smectic C* (SmC*) mesogens with a chiral fluorenol core as the only stereopolar unit are undertaken. The role of chiral smectic C* (SmC*) liquid crystals in the commercial development of high-resolution reflective microdisplays is discussed.

The ferroelectric SmC* phase is a chiral liquid crystal phase characterized by a spontaneous electric polarization (Ps), which can be coupled to an electric field to produce an electrooptical light shutter. In a ferroelectric SmC* host, the trans-cis photoisomerization of an achiral azobenzene dopant destabilizes the SmC* phase, which results in a decrease of polarization at constant temperature.

We investigate the origins of 'de Vries-like' liquid crystalline behaviour by introducing an ethynyl spacer in the core of the tricarbosilane-terminated 5-phenylpyrimidine mesogens QL16-6 and QL17-6. The rationale for this structural change is based on the assumption that an ethynyl spacer would create more free volume in the core sub-layer and therefore decrease the orientational order parameter S2 in the SmA phase. The tricarbosilane-terminated mesogens WL41-5 and WL42-6 with a 5-(phenylethynyl)pyrimidine core in either a normal or inverted orientation were synthesised, and their mesomorphic and 'de Vries-like' properties characterised using polarised optical microscopy, differential scanning calorimetry, birefringence measurements, small–angle (SAXS) and 2D X-ray scattering. Reduction factors R derived from SAXS and optical tilt angle measurements suggest that neither WL41-5 (R = 0.49) nor WL42-6 (R = 0.80) exhibit 'de Vries-like' properties. The S2(T) profiles show an increase in orientational order with decreasing temperature and a sharp discontinuity at the SmA-SmC transition, which is consistent with 'de Vries-like' behaviour. However, the Leff(T) profiles suggest an increase in interdigitation that reduces the positive effect of increasing S2 in compensating for the molecular tilt. [ABSTRACT FROM AUTHOR]

First example of a photochemically bistable FLC photoswitch using a photochromic dithienylethene dopant is presented. The spontaneous polarization of a ferroelectric liquid crystal can be modulated reversibly via photoisomerization of the dithienylethene dopant.

The (R,R)-6,6'-bis(1-methylheptyloxy)-5,5'-dinitrothioindigo was synthesized based on photoirradiation techniques and analyzed to characterize the kinetics of spontaneous polarization. The complex compound was composed of chiral side chains that were strongly coupled with the thioindigo core via steric and dipole-dipole coupling with the adjacent nitro groups. The spontaneous polarization of the ferroelectric liquid crystal was also enhanced without the concomittant destabilization of the chiral smectic phase.