Low-Field NMR Study of Shortcake Biscuits with Cricket Powder,and Their Nutritional and Physical Characteristics

The growing human population renders challenges for the future supply of food products with high nutritional value. Here, we enhanced the functional and nutritional value of biscuits, a popular sweet snack, by replacing the wheat flour with 2%, 6%, or 10% (w/w) cricket powder. Consumer acceptance ratings for reference and 2% augmented cookies were comparable, whereas the higher levels of enhancement received inferior consumer scores. This relatively small change in biscuit recipe provided significant and nutritionally desirable enhancements in the biscuits, observed in a series of analyses. An increase in the protein content was observed, including essential amino acids, as well as minerals and fat. This conversion also affected the physical properties of the biscuits, including hardness, and water molecular dynamics measured by ¹H NMR. Cricket powder-augmented biscuits join the line of enhanced, functionally superior food products. This and similar food augmentation provide a viable scenario to meet the human food demands in the future.     

A comparison of rigid and flexible water models in collisions of monomers and small clusters

In this study we have investigated the dynamics of small water clusters using microcanonical molecular dynamics simulations. The clusters are formed by colliding vapor monomers with target clusters of two and five molecules. The monomers are sampled from a thermal ensemble at T=300 K and target clusters with several total energies are considered. We compare rigid extended simple point charge water with flexible counterparts having intramolecular harmonic bonds with force constants 10(3) and 10(5) kcal(mol A2). We show that the lifetimes of the clusters formed via collision process are similar for the rigid model and the flexible model with the bigger force constant, if the translational temperatures of the target cluster molecules are equal. The model with the smaller force constant results in much longer lifetimes due to the stabilizing effect caused by the kinetic energy transfer into internal vibration of the molecules. This process may take several hundreds of picoseconds, giving rise to time-dependent decay rates of constant-energy clusters. A study of binary collisions of water molecules shows that the introduction of flexibility to the molecules increases the possibility of dimer formation and thus offers an alternative route for dimer production in vapors. Our results imply that allowing for internal degrees of freedom is likely to enhance gas-liquid nucleation rates in water simulations.     

Electromagnetic moments of short lived β emitters 21F, 23Mg, 27Si and 39Ca

The β-NMR spectra of ²¹F, ²³Mg, ²⁷Si and ³⁹Ca which were produced in heavy ion collisions and implanted in various crystals have been observed. The magnetic moments of ²¹F and ²⁷Si were determined to be |μ(²¹F)| = 3.9194 ± 0.0012 μ_N and |μ(²⁷Si)| = 0.8653 ± 0.0003 μ_N, respectively. The electric quadrupole coupling constants were determined for the first time to be |eqQ(²¹F in MgF₂)/h|= 9.94 ± 0.09 MHz, |eqQ(²³Mg in MgF₂)/h|= 1.96 ± 0.06 MHz, |eqQ(²⁷Si in Al₂O₃)/h|= 1.90 ± 0.12 MHz, |eqQ(³⁹Ca in CaCO₃)/h|= 0.60 ± 0.04 MHz. From the present eqQ/h, the Q moments were deduced as |Q(²¹F)|= 110 ± 22 mb, |Q(²³Mg)|= 114 ± 3 mb, |Q(²⁷Si)|= 60 ± 13 mb and |Q(³⁹Ca)|= 36± 7 mb. The present data were compared with the theoretical values obtained by the OXBASH shell model code. This revised version was published online in August 2006 with corrections to the Cover Date.     

Extended operation of synchronously pumped optical parametric oscillators to longer idler wavelengths

A synchronously pumped optical parametric oscillator, based on periodically poled lithium niobate, has operated at idler wavelengths out to 7.3 microm . Directly measured idler output powers (average) are 4.2 mW at 6.1 microm, 0.5 mW at 7.0 microm, and 0.04 mW at 7.25 microm . Characterization of the idler output indicates essentially bandwidth-limited and diffraction-limited operation.     

The influence of molecular rotational diffusion on Gaussian pulse-induced third-order electric polarisation in liquids

Time evolution curves of the changes in nonlinear electric polarisation induced by Gaussian pulses are calculated theoretically with the Smoluchowski-Debye molecular rotational diffusion equation not including the influence of the moment of inertia of the molecules or their interactions. Graphs show the dynamics of the third-order electric polarisation versus the Gaussian pulse width and the parameter R, defining the balance between the dipolar and anisotropically polarisable properties of the molecules.     

Differences Between Flexible and Rigid Endoscopy in Assessing the Posterior Glottic Chink

Objective

To determine whether different modalities of laryngeal examination produce differences in the assessment of the posterior glottic chink (PGC), and whether the prevalence of PGC differs by gender.

Introduction

The PGC has been described as a triangular laryngeal space between the posterior laryngeal wall and the vocal processes during glottic closure found commonly in human females, but less often in males. The purpose of this study was not only to identify whether there are gender differences in prevalence of posterior glottic but also to determine whether there is a difference in detection of this configuration dependent on the modality of laryngeal imaging, specifically flexible nasopharyngolaryngoscopy (FNPL) versus rigid laryngoscopy (RL).

Methods

A review of 104 consecutive initial laryngeal examinations was performed. All patients underwent both flexible laryngoscopy (FL) and RL performed under stroboscopic light. Patients with immobile vocal folds, masses causing glottic gaps, atrophy, or severe muscle tension dysphonia causing an inability to fully visualize the entire length of the vocal fold were excluded. In the remaining patients, the posterior glottic configuration showing a posterior chink in relation to the vocal process was graded on a 0–4 scale (called the Posterior Glottic Closure Score [PGCS]); 0 was used to indicate a closed glottis and 4 the most open configuration without creating a complete glottic gap. PGCSs for males were compared with those of females, and the PGCSs obtained by flexible nasopharyngolaryngoscopy was compared with RL.

Results

Fifty-two patients were included in the study. Twenty-four of the patients were male, and 28 were female. The average age of the patients was 48.4 years (SD ± 17.35), and the range was 15–81 years. On RL, eight males had a PGCS 1–4, that is, evidence of PGC, and 23 females had a PGCS 1–4. On flexible nasopharyngolaryngoscopy, only four males had a PGCS 1–4 and 24 females had PGCS 1–4. Twenty-two females had a PGC detected by both modalities, and the PGCS was significantly higher using RL (2.73 ± 0.70 vs 2.14 ± 0.834) than FL. For the four males in which PGC was detected by both modalities, there was no statistical significance when comparing the PGCS between RL and FL (1.75 ± 0.96 vs 1.75 ± 0.5, P < 0.05). When comparing only males and females who had a PGC (PGCS 1–4), females had a higher PGCS (2.65 ± 0.78) than males (1.75 ± 0.71, P < 0.05) on RL, indicating a more open posterior glottis in females. On flexible examination, there was no difference detected in the average PGCS, 2.08 ± 0.83 for females and males 1.75 ± 0.50. PGCs were more common in younger (age 43 years) than older (age 54–56 years) subjects for both laryngoscopic modalities.

Conclusion

From this pilot study, we determined that there is a difference in male and female PGC prevalence and size. PGC is more common in females than males. Prevalence (or the detection rate) is about the same with RL and FL in females, but higher with RL than FL in males. The average score of the glottic opening, when present, was statistically significantly different between RL and FL in females but not in males. Furthermore, females had a larger PGCS on both modalities when compared with males, although this difference was only found to be statistically significant on RL; and complete glottic closure was more common in older than in younger subjects.     

UV‐induced transformations of matrix‐isolated 1,3,4‐thiadiazole‐2‐thiones

Monomers of 5‐mercapto‐1,3,4‐thiadiazole‐2‐thione (bismuthiol) were studied using an experimental matrix‐isolation technique as well as by carrying out theoretical quantum chemical calculations. The calculations, performed using the quadratic configuration interaction method with single and double excitations (QCISD)/6‐31++G(d,p)//DFT(B3LYP)/6‐311++G(2d,p), predict that the thione–thiol tautomer of bismuthiol should be significantly (by more than 19 kJ mol^?1) more stable than other tautomeric forms. Accordingly, only the signatures of the thione–thiol tautomer were observed in the FT‐IR spectrum of bismuthiol, recorded directly after deposition of an Ar matrix. UV (λ > 320 nm) irradiation induced the conversion of the thione–thiol tautomer into the dithiol form. Analogous investigations were carried out for two related compounds: 5‐methyl‐1,3,4‐thiadiazole‐2‐thione and 5‐methylthio‐1,3,4‐thiadiazole‐2‐thione. For these two species, only the thione tautomeric forms were observed after deposition of Ar matrices. These tautomers were predicted (by QCISD calculations) to be more stable (by at least 19 kJ mol^?1) than other tautomeric forms. Upon UV irradiation, the most stable thione forms of these compounds were transformed into the corresponding thiol tautomers. Direct observation of the thione → thiol phototautomeric processes provides a clear proof that intramolecular proton transfer reaction can occur in molecules, such as bismuthiol, in spite of the increased NH···S distance, in comparison to other phototautomerizing species studied so far. All the isomers of the studied compounds (substrates and products of the photoreactions) were identified by comparison of their IR spectra with the spectra calculated at the DFT(B3LYP)/6‐311++G(2d,p) level of theory for possible isomeric structures. Copyright © 2009 John Wiley & Sons, Ltd.     

Metallization of the β-SiC(100) 3 × 2 surface: A DFT investigation

Using density functional theory (DFT) we report results for the electronic structure and vibrational dynamics of hydrogenated silicon carbide (001) (3 × 2) surfaces with various levels of hydrogenation. These results were obtained using density functional theory with a generalized gradient exchange correlation function. The calculations reveal that metallization can be achieved via hydrogen atoms occupying the second silicon layer. Further increase of hydrogen occupation on the second silicon layer sites results in a loss of this metallization. For the former scenario, where metallization occurs, we found a new vibrational mode at 1870 cm^? 1, which is distinct from the mode associated with hydrogen atoms on the first layer. Furthermore, we found the diffusion barrier for a hydrogen atom to move from the second to the third silicon layer to be 258 meV.     

Computer simulations of the growth of synthetic peptide fibres

We present a coarse-grained computer model designed to study the growth of fibres in a synthetic self-assembling peptide system. The system consists of two 28 residue a \alpha -helical sequences, denoted AB and CD, in which the interactions between the half peptides, A, B, C and D, may be tuned individually to promote different types of growth behaviour. In the model, AB and CD are represented by double ended rods, with interaction sites distributed along their lengths. Monte Carlo simulations are performed to follow fibre growth. It is found that lateral and longitudinal growth of the fibre are governed by different mechanisms --the former is diffusion limited with a very small activation energy for the addition of units, whereas the latter occurs via a process of secondary nucleation at the fibre ends. As a result, longitudinal growth generally proceeds more slowly than lateral growth. Furthermore, it is shown that the aspect ratio of the growing fibre may be controlled by adjusting the temperature and the relative strengths of the interactions. The predictions of the model are discussed in the context of published data from real peptide systems.     

Microscopic <Emphasis Type="Italic">K</Emphasis><Superscript>+</Superscript>-nucleus optical potential and calculations of differential elastic-scattering cross sections and total reaction cross sections

The differential elastic-scattering cross sections and the total reaction cross sections for the interaction of K ⁺ mesons with ¹²C and ⁴⁰Ca nuclei at beam momenta of 0.635, 0.715, and 0.8 GeV/c are calculated. The microscopic optical potential derived in the high-energy approximation is used in these calculations. It is determined by the amplitude for kaon-nucleon scattering and the density distribution of pointlike nucleons of the target nucleus. In the high-energy approximation, the Klein-Gordon-Fock equation reduces to the form of the Schrödinger equation. It is shown that small distinctions between the reduction methods do not lead to significant changes in differential elastic-scattering cross sections, but the effects of relativization as such are quite large. Good agreement with experimental data on elastic K ⁺ A scattering is attained. The total reaction cross sections can be described upon adding, to the volume potential, a term that takes the form of its derivative and which has a maximum at the periphery, its contribution being fitted to experimental data.