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To study the scattering of CO off a movable Cu(100) surface, extensive multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) calculations are performed based on the SAP [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] potential energy surface in conjunction with a recently developed expansion model [Q. Meng and H.-D. Meyer, J. Chem. Phys. 143, 164310 (2015)] for including lattice motion. The surface vibration potential is constructed by a sum of Morse potentials where the parameters are determined by simulating the vibrational energies of a clean Cu(100) surface. Having constructed the total Hamiltonian, extensive dynamical calculations in both timeindependent and time-dependent schemes are performed. Two-layer MCTDH (i.e., normal MCTDH) block-improved-relaxations (time-independent scheme) show that increasing the number of included surface vibrational dimensions lets the vibrational energies of CO/Cu(100) decrease for the frustrated translation (T mode), which is of low energy but increase those of the frustrated rotation (R mode) and the CO-Cu stretch (S mode), whose vibrational energies are larger than the energies of the in-plane surface vibrations (~79 cm-1). This energy-shifting behavior was predicted and discussed by a simple model in our previous publication [Q. Meng and H.-D. Meyer, J. Chem. Phys. 143, 164310 (2015)]. By the flux analysis of the MCTDH/ML-MCTDH propagated wave packets, we calculated the sticking probabilities for the X + 0D, X + 1D, X + 3D, X + 5D, and X + 15D systems, where "X" stands for the used dimensionality of the CO/rigid-surface system and the second entry denotes the number of surface degrees of freedom included. From these sticking probabilities, the X + 5D/15D calculations predict a slower decrease of sticking with increasing energy as compared to the sticking of the X + 0D/1D/3D calculations. This is because the translational energy of CO is more easily transferred to surface vibrations, when the vibrational dimensionality of the surface is enlarged. [ABSTRACT FROM AUTHOR]

To accurately compute the rates of the abstraction channels of hydrogen plus ethane (Et), propane (Pr), and dimethyl ether (DME), ring-polymer molecular dynamics (RPMD) method is used in conjunction with the recently constructed local permutation invariant polynomial neural-networks potential energy surface of the parent H + CH4 system [Q. Meng et al., J. Chem. Phys. 144, 154312 (2016)]. For H + Et, one of the H atoms in CH4 of the parent system is replaced by a methyl group, while for the H + DME reaction, it is replaced by the methoxyl group. For the H + Pr reaction, replacing one of the H atoms in CH4 by an ethyl group, the terminal channel is built, meanwhile the middle channel is considered through replacing two H atoms in CH4 by two methyl groups. Since the potential energy barriers of the title reactions must differ from the H + CH4 barrier, the corrections have to be made by computing the ratio of free-energy barriers between H + CH4 and the title reactions at coupled cluster with a full treatment singles and doubles (where the triples contribution is calculated by perturbation theory, that is, CCSD(T)) level. Comparing the present RPMD rates with the previous theoretical and experimental results, good agreement can be found. Moreover, probable reasons for the deviation between the present RPMD rates and the previous experimental ones are discussed. [ABSTRACT FROM AUTHOR]

To fast and accurately compute rate coefficients of the H/D + CH4→H2/HD + CH3 reactions, we propose a segmented strategy for fitting suitable potential energy surface (PES), on which ring-polymer molecular dynamics (RPMD) simulations are performed. On the basis of recently developed permutation invariant polynomial neural-network approach [J. Li et al., J. Chem. Phys. 142, 204302 (2015)], PESs in local configuration spaces are constructed. In this strategy, global PES is divided into three parts, including asymptotic, intermediate, and interaction parts, along the reaction coordinate. Since less fitting parameters are involved in the local PESs, the computational efficiency for operating the PES routine is largely enhanced by a factor of ~20, comparing with that for global PES. On interaction part, the RPMD computational time for the transmission coefficient can be further efficiently reduced by cutting off the redundant part of the child trajectories. For H + CH4, good agreements among the present RPMD rates and those from previous simulations as well as experimental results are found. For D + CH4, on the other hand, qualitative agreement between present RPMD and experimental results is predicted. [ABSTRACT FROM AUTHOR]

Molecular-surface studies are often done by assuming a corrugated, static (i.e., rigid) surface. To be able to investigate the effects that vibrations of surface atoms may have on spectra and cross sections, an expansion Hamiltonian model is proposed on the basis of the recently reported [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] SAP potential energy surface (PES), which was built for the CO/Cu(100) system with a rigid surface. In contrast to other molecule-surface coupling models, such as the modified surface oscillator model, the coupling between the adsorbed molecule and the surface atoms is already included in the present expansion SAP-PES model, in which a Taylor expansion around the equilibrium positions of the surface atoms is performed. To test the quality of the Taylor expansion, a direct model, that is avoiding the expansion, is also studied. The latter, however, requests that there is only one movable surface atom included. On the basis of the present expansion and direct models, the effects of a moving top copper atom (the one to which CO is bound) on the energy levels of a bound CO/Cu(100) system are studied. For this purpose, the multiconfiguration time-dependent Hartree calculations are carried out to obtain the vibrational fundamentals and overtones of the CO/Cu(100) system including a movable top copper atom. In order to interpret the results, a simple model consisting of two coupled harmonic oscillators is introduced. From these calculations, the vibrational levels of the CO/Cu(100) system as function of the frequency of the top copper atom are discussed. [ABSTRACT FROM AUTHOR]

The ring polymer molecular dynamics (RPMD) calculations are performed to calculate rate constants for the title reaction on the recently constructed potential energy surface based on permutation invariant polynomial (PIP) neural-network (NN) fitting [J. Li et al., J. Chem. Phys. 142, 204302 (2015)]. By inspecting convergence, 16 beads are used in computing free-energy barriers at 300 K ≤ T ≤ 1000 K, while different numbers of beads are used for transmission coefficients. The present RPMD rates are in excellent agreement with quantum rates computed on the same potential energy surface, as well as with the experimental measurements, demonstrating further that the RPMDis capable of producing accurate rates for polyatomic chemical reactions even at rather low temperatures. [ABSTRACT FROM AUTHOR]

Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian (MMVCH) model, we perform a full dimensional (9D) quantum dynamical study on the simplest Criegee intermediate, formaldehyde oxide, in five lower-lying singlet electronic states. The ultraviolet (UV) spectrum is then simulated by a Fourier transform of the auto-correlation function. The MMVCH model is built based on extensive MRCI(8e,8o)/aug-cc-pVTZ calculations. To ensure a fast convergence of the final calculations, a large number of ML-MCTDH test calculations is performed to find an appropriate multilayer separations (ML-trees) of the ML-MCTDH nuclear wave functions, and the dynamical calculations are carefully checked to ensure that the calculations are well converged. To compare the computational efficiency, standard MCTDH simulations using the same Hamiltonian are also performed. A comparison of the MCTDH and ML-MCTDH calculations shows that even for the present not-too-large system (9D here) the ML-MCTDH calculations can save a considerable amount of computational resources while producing identical spectra as the MCTDH calculations. Furthermore, the present theoretical B¹A' ← X¹A' UV spectral band and the corresponding experimental measurements [J. M. Beames, F. Liu, L. Lu, and M. I. Lester, J. Am. Chem. Soc.134, 20045-20048 (2012); L. Sheps, J. Phys. Chem. Lett.4, 4201-4205 (2013); W.-L. Ting, Y.-H. Chen, W. Chao, M. C. Smith, and J. J.-M. Lin, Phys. Chem. Chem. Phys.16, 10438-10443 (2014)] are discussed. To the best of our knowledge, this is the first theoretical UV spectrum simulated for this molecule including nuclear motion beyond an adiabatic harmonic approximation. [ABSTRACT FROM AUTHOR]

Structural analysis does not consider weld seam. Research on welding seldom pays attention to structural strength analysis. The working conditions of super large structure are complex, and the design requirements are very high. The coupled relationship between the structure of weld toe and frame stiffness in actual working conditions is analyzed to improve the accuracy of finite element model. Using the finite element method as basis, this study establishes the finite element model for the frame. The fillet joint models for the different forms of weld toe are established on the basis of thermo-elastic/plastic theory. Weld toe optimization scheme is applied to analyze frame strength. The accuracy of the model is verified by experiments. Results show that high stress appears at the connection position of the left-right longitudinal beam and rear torsion tube and the middle of rear torsion tube due to the interaction of torsion and braking. Stress between the frontal longitudinal beam and portal-type girder assembly does not significantly vary. The weld height and toe of the fillet joint are 20 mm, and the stress peak value is small. The stress distribution of the frame is analyzed by optimizing the weld toe. The stress peak value is reduced from 453.8 MPa to 340.6 MPa. Through the repair welding of the weld toe position for the optimization scheme, the welding seam surface forms a concave arc and reduces the stress concentration effectively. Failure time of the frame increases by no more than 5000 hours and does not exhibit fatigue failure. Research results are crucial for establishing coupled relationship with weld toe and frame strength and optimizing welding. [ABSTRACT FROM AUTHOR]

Most of the existing research related to the handling stability of articulated vehicles takes the front wheel angle as input and neglects the influence of the steering system and regards these vehicles as moving in planes that parallel the ground plane. The established dynamic model cannot meet the requirements of stability control under unmanned and high-speed working conditions. This research proposed a fusion modeling method based on the kinematics and dynamics of vehicles to improve the precision of a driving dynamic model. The proposed method initially took the steering wheel angle as input to establish the kinematic model for the corresponding relation of the hydraulic system flow and pressure, the articulated angle of front and rear frames, and the output force of left and right steering hydraulic cylinders. A dynamic model considering the axle load transfer and interactions between the front frame and the rear body in a three-dimensional coordinate system was then established. A driving dynamic model of an entire vehicle was also constructed by coupling the kinematic and dynamic models. Finally, real vehicle test data of a 60-ton articulated vehicle were used to verify the proposed Automatic Dynamic Analysis of Mechanical Systems (ADAMS) driving model in this study. Results confirm that the error about the steady-state yaw rate in the simulation and real vehicle tests did not exceed 0.01 rad/s. Therefore, the established driving dynamic model can describe the dynamic response accurately. This study concludes that the proposed fusion modeling method based on the combination of kinematics and dynamics can effectively improve the accuracy of the articulated vehicle model and further provide a technical reference for the study on a driving stability control strategy. [ABSTRACT FROM AUTHOR]

For studying O- and Cl-loss predissociation mechanisms of OClO (A2A2), we calculated O- and Cl-loss dissociation potential energy curves (adiabatic minimum-energy dissociation paths) of several low-lying doublet and quartet states at the CASPT2 level and located the MECPs (minimum energy crossing points) for many pairs of the potential energy surfaces (PESs) at the CASPT2 and CASSCF levels. On the basis of our calculation results (including the spin−orbit couplings at the MECPs), we predict three processes for O-loss predissociation of A2A2and four processes for Cl-loss predissociation of A2A2. The most favorable process for O-loss predissociation is OClO (A2A2) → A2A2/1 2B2MECP → 1 2B2(1 2A′) → O (3Pg) + ClO (X2Π) (the first O-loss limit), and the needed energy for this process from X2B1is 2.92 eV. The most favorable process for Cl-loss predissociation is OClO (A2A2) → A2A2/1 2B2MECP → TS1 (1 2B2) → 1 2B2/1 2A1MECP → Cl (2Pu) + O2(X3Σg−) (the first limit), and the needed energy is 3.08 eV. In the previously suggested mechanisms (processes), the A2A2state was considered to go to the important 1 2B2state via 1 2A1(A2A2→ 1 2A1→ 1 2B2). In the present study we have found that the A2A2state can directly go to 1 2B2(at the located A2A2/1 2B2MECP the CASPT2 energy (relative to X2B1) and CASSCF spin−orbit coupling are 2.92 eV and 61.3 cm−1, respectively). We have compared our processes (A2A2→ 1 2B2→ ...) with the processes (A2A2→ 1 2A1→ 1 2B2→ ...) suggested in the previous MRCI studies and rewritten by us using our calculation results. Energetically the MRCI process for O-loss predissociation (to the first limit) is only slightly (0.13 eV) more favorable than our process, and the MRCI processes for Cl-loss predissociation (to the first and second limits) need the same energies as our processes. By considering the probabilities of radiationless transitions, the MRCI processes are less favorable than our processes since the MRCI processes proceed via more PES/PES crossings (more MECPs). The experimental facts concerning the photodissociation are explained. [ABSTRACT FROM AUTHOR]

The adiabatic path for the N2(X1 [image omitted]) + O+(4Su) → NO+(X1Σ+) + N(4Su) reaction is presented based on the CASPT2 O- and N-loss dissociation potential energy curves (PECs) of the 14A'' (not 14Σ-) state of N2O+ and it has a small barrier of 0.45 eV (0.34 eV with the CASSCF zero-point energy corrections) in good agreement with the experimental value of 0.33 ± 0.08 eV. Based on the CASPT2 O- and N-loss dissociation PECs of the X2Π state of N2O +and the calculated energies and spin-orbital coupling values at the located MECPs (minimum energy crossing points) for the X2Π/14A'' state pairs, a nonadiabatic path via the 14A''/12A'' O-loss MECP, X2Π minimum, and 12A''/14A'' N-loss MECP is presented. The CASPT2 energetic results indicate that this nonadiabatic process can occur without external energy. Based on the adiabatic and nonadiabatic paths, we explain the experimental facts for the reaction: small cross-section at low energy and an onset of a strong increase in cross-section at a certain energy value. Mechanisms for O- and N-loss predissociation of the X2Π state by 14A'' via the 12A''/14A'' O- and N-loss MECPs, respectively, are described, and the experimental facts are explained using the results of our energetic and spin-orbit coupling calculations. [ABSTRACT FROM AUTHOR]

Polymer-dispersed liquid crystal (PDLC) films were prepared from thermal polymerisation-induced phase separation in heat-curable monomers/nematic liquid crystal (LC) mixtures. For PDLCs with a certain amount of LCs, the microstructure and the refractive index of polymer networks could be influenced by the relative content of epoxy monomers, owing to their different chemical structures. The effect of these factors on the electro-optic properties of films was also investigated. [ABSTRACT FROM AUTHOR]

For a theoretical model study on the cyclic reaction of 4-hydroxybutanal (4-OH-BL), we have examined five assumed reaction pathways (I–V) by performing the B3LYP calculations in the gas phase and self-consistent isodensity polarized continuum model (SCIPCM)-B3LYP calculations in aqueous solution. Pathways II (4-OH-BL + H+), III (4-OH-BL + H3O+), and IV (4-OH-BL + H3O+ + H2O) represent three models for the cyclic reaction catalyzed by Brønsted acids. The present study leads to the following conclusions concerning the five pathways (mainly on the basis of the calculation results in the solution). The high barrier along pathway I (with no catalyst) implies that the reaction does not occur without a catalyst, and the extremely large stabilization energy of the intermediate implies that pathway II is not a realistic model for the reaction catalyzed by Brønsted acid. Along pathway III, there are two intermediates and a transition state in between, and they are 10–16 kcal/mol lower in energy than the reactants (4-OH-BL + H3O+). Along pathway IV, there is only one intermediate, and it is 20.6 kcal/mol lower in energy than the reactants (4-OH-BL + H3O+ + H2O). Pathways III and IV are predicted to be feasible. Energetically, pathway IV is more favourable than pathway III and it is considered as a rational model for the cyclic reaction of 4-OH-BL catalyzed by Brønsted acid. Our calculations for pathway V (catalyzed by H2O) indicate that the water molecule may also serve as a catalyst for the cyclic reaction. The transition state along pathway V is 20.0 kcal/mol higher in energy than the reactants (4-OH-BL + H2O), and one can clearly see the “proton wire” in its structure. Our calculations show strong solvent effects on energetics of the charged intermediates along pathways II, III, and IV. [ABSTRACT FROM AUTHOR]

Genetic variation of insulin-like growth factor binding protein-3 was analyzed in 17 pig breeds (14 native Chinese and 3 European). Using PCR-single strand conformation polymorphism, we found a polymorphism in intron 2, and this SNP was the combined mutation of G897T-G903A-C911T. The Chinese breeds carried a higher TAT/TAT genotype frequency (over 50%), except for Bamei (22%), Yujiang Black (0.0%), and Erhualian (10.0%); the European breeds had a higher GGC/GGC genotype frequency (Large White 1.67%, Landrace 13.89%, Duroc 0.0%). The allelic frequency of TAT in Chinese breeds was over 50%, except for Yujiang Black (12.5%); the allelic frequency of GGC was over 50% in all European breeds. The effect of genotype on 43 performance traits was investigated in one population (Lantang × Landrace). Pigs with the TAT/TAT genotype had higher B-point and C-point back-fat thickness than pigs with the GGC/GGC genotype. The TAT/TAT pigs also scored higher in meat color than the GGC/GGC pigs. These results implied that IGFBP-3 may affect meat quality and carcass traits. [ABSTRACT FROM AUTHOR]

Muscle regeneration is a complex process relying on precise teamwork between multiple cell types, including muscle stem cells (MuSCs) and fibroadipogenic progenitors (FAPs). FAPs are also the main source of intramuscular adipose tissue (IMAT). Muscles without FAPs exhibit decreased IMAT infiltration but also deficient muscle regeneration, indicating the importance of FAPs in the repair process. Here, we demonstrate the presence of bidirectional crosstalk between FAPs and MuSCs via their secretion of extracellular vesicles (EVs) containing distinct clusters of miRNAs that is crucial for normal muscle regeneration. Thus, after acute muscle injury, there is activation of FAPs leading to a transient rise in IMAT. These FAPs also release EVs enriched with a selected group of miRNAs, a number of which come from an imprinted region on chromosome 12. The most abundant of these is miR-127-3p, which targets the sphingosine-1-phosphate receptor S1pr3 and activates myogenesis. Indeed, intramuscular injection of EVs from immortalized FAPs speeds regeneration of injured muscle. In late stages of muscle repair, in a feedback loop, MuSCs and their derived myoblasts/myotubes secrete EVs enriched in miR-206-3p and miR-27a/b-3p. The miRNAs repress FAP adipogenesis, allowing full muscle regeneration. Together, the reciprocal communication between FAPs and muscle cells via miRNAs in their secreted EVs plays a critical role in limiting IMAT infiltration while stimulating muscle regeneration, hence providing an important mechanism for skeletal muscle repair and homeostasis. [ABSTRACT FROM AUTHOR]

Background: Genesis of novel gene regulatory modules is largely responsible for morphological and functional evolution. De novo generation of novel cis-regulatory elements (CREs) is much rarer than genomic events that alter existing CREs such as transposition, promoter switching or co-option. Only one case of de novo generation has been reported to date, in fish and without involvement of phenotype alteration. Yet, this event likely occurs in other animals and helps drive genetic/phenotypic variation. Results: Using a porcine model of spontaneous hearing loss not previously characterized we performed gene mapping and mutation screening to determine the genetic foundation of the phenotype. We identified a mutation in the non-regulatory region of the melanocyte-specific promoter of microphthalmia-associated transcription factor (MITF) gene that generated a novel silencer. The consequent elimination of expression of the MITF-M isoform led to early degeneration of the intermediate cells of the cochlear stria vascularis and profound hearing loss, as well as depigmentation, all of which resemble the typical phenotype of Waardenburg syndrome in humans. The mutation exclusively affected MITF-M and no other isoforms. The essential function of Mitf-m in hearing development was further validated using a knock-out mouse model. Conclusions: Elimination of the MITF-M isoform alone is sufficient to cause deafness and depigmentation. To our knowledge, this study provides the first evidence of a de novo CRE in mammals that produces a systemic functional effect. [ABSTRACT FROM AUTHOR]

Overexpression of the p16 protein has been reported in breast cancer and may trigger the secretion of antibodies against itself. Circulating anti-p16 antibodies that were detected with a recombinant protein have been reported in breast cancer. The present study was designed to determine whether the levels of circulating IgG antibody to p16 protein-derived linear antigens are altered in breast cancer. An enzyme-linked immunosorbent assay (ELISA) was developed in-house to determine circulating IgG against peptide antigens derived from the p16 protein in 152 female breast cancer patients and 160 healthy female subjects. The Student's t-test revealed that breast cancer patients exhibited significantly higher levels of anti-p16 IgG antibody compared to control subjects (t=2.02, P=0.045). In addition, ductal cancer appeared to be the main type contributing to the increased levels of circulating anti-p16 antibodies (t=2.08, P=0.038). Of all four stages of breast cancer, stage I was associated with the highest levels of IgG antibody (t=2.02, P=0.045) and receiver operating characteristic (ROC) analysis demonstrated that the area under the ROC curve was 0.74 (95% confidence interval: 0.65-083) and that the sensitivity against a specificity of 90% was 30.3%. Therefore, the levels of circulating IgG antibody to the p16 protein may be a potential biomarker for early diagnosis of breast cancer. [ABSTRACT FROM AUTHOR]

Background: The p53 tumor suppressor gene is mutated or deleted in nearly half of human cancers. The murine double minute 2 (Mdm2) and Mdmx represent two important cellular regulators of p53. The aim of this study was to evaluate the abnormalities of p53, Mdmx and Mdm2 genes in archived breast cancers. Methods: We assessed the genetic instability at p53, Mdmx and Mdm2 using high resolution multi-color fluorescent in situ hybridization (FISH) protocol and detected the expression status of the tumor protein p53 (TP53), MDMx and MDM2 by immunohistochemistry in 115 archived samples of infiltrating ductal breast carcinomas with foci of ductal carcinoma in situ (DCIS) components. Results: The presence of p53 allelic loss and/or TP53 overexpression was observed in 38% out of all patients, and was significantly more often in larger, high grade, ER negative and high ki67 tumors. Mdmx amplification with low-level increase of gene copy number is at high frequency while Mdm2 amplification is rare in primary breast cancer. Mdmx amplification was seen in more invasive carcinomas than preinvasive lesions. MDMx and MDM2 overexpression were detected in 65% and 38% of all cases respectively. Moreover it was showed that most tumors contained either p53 dysfunction or Mdm2 alteration, but not both. This distribution was significant (P < 0.05). Inverse correlation between Mdmx amplification/overexpression and p53 disfunction was also observed (P < 0.05). Conclusions: Our results suggest the involvement of Mdm2 and Mdmx in p53-independent breast carcinogenesis and Mdmx may contribute to the regulation of p53 independently of Mdm2. [ABSTRACT FROM AUTHOR]

In science, the guinea pig is known as one of the gold standards for modeling human disease. It is especially important as a molecular and cellular biology model for studying the human immune system, as its immunological genes are more similar to human genes than are those of mice. The utility of the guinea pig as a model organism can be further enhanced by further characterization of the genes encoding components of the immune system. Here, we report the genomic organization of the guinea pig immunoglobulin (Ig) heavy and light chain genes. The guinea pig IgH locus is located in genomic scaffolds 54 and 75, and spans approximately 6,480 kb. 507 VH segments (94 potentially functional genes and 413 pseudogenes), 41 DH segments, six JH segments, four constant region genes (m, c, e, and a), and one reverse d remnant fragment were identified within the two scaffolds. Many VH pseudogenes were found within the guinea pig, and likely constituted a potential donor pool for gene conversion during evolution. The Igk locus mapped to a 4,029 kb region of scaffold 37 and 24 is composed of 349 Vk (111 potentially functional genes and 238 pseudogenes), three Jk and one Ck genes. The Igγ locus spans 1,642 kb in scaffold 4 and consists of 142 Vl (58 potentially functional genes and 84 pseudogenes) and 11 Jl -Cl clusters. Phylogenetic analysis suggested the guinea pig's large germline VH gene segments appear to form limited gene families. Therefore, this species may generate antibody diversity via a gene conversion-like mechanism associated with its pseudogene reserves. [ABSTRACT FROM AUTHOR]

Previous studies on the immunoglobulin (Ig) genes in avian species are limited (mainly to galliformes and anseriformes) but have revealed several interesting features, including the absence of the IgD and Igk encoding genes, inversion of the IgA encoding gene and the use of gene conversion as the primary mechanism to generate an antibody repertoire. To better understand the Ig genes and their evolutionary development in birds, we analyzed the Ig genes in the ostrich (Struthio camelus), which is one of the most primitive birds. Similar to the chicken and duck, the ostrich expressed only three IgH chain isotypes (IgM, IgA and IgY) and l light chains. The IgM and IgY constant domains are similar to their counterparts described in other vertebrates. Although conventional IgM, IgA and IgY cDNAs were identified in the ostrich, we also detected a transcript encoding a short membrane-bound form of IgA (lacking the last two CH exons) that was undetectable at the protein level. No IgD or k encoding genes were identified. The presence of a single leader peptide in the expressed heavy chain and light chain V regions indicates that gene conversion also plays a major role in the generation of antibody diversity in the ostrich. Because the ostrich is one of the most primitive living aves, this study suggests that the distinct features of the bird Ig genes appeared very early during the divergence of the avian species and are thus shared by most, if not all, avian species. [ABSTRACT FROM AUTHOR]

Polymer-dispersed liquid crystal (PDLC) films were prepared by photochemical polymerisation from an ultraviolet-curable monomer/crosslinking agent/initiator/liquid crystal (LC) mixture. The influences of the chain length of crosslinking agents on the PDLC system have been studied. The microstructures of the PDLC films were strongly influenced by the chain length of the crosslinker, which in turn influences the electro-optic properties of PDLC films. It is proved that adjusting the chain length of the crosslinking agents and the LC content can produce PDLC films that have good electro-optic properties with a lower LC content. [ABSTRACT FROM AUTHOR]

A bandwidth-controllable reflective gel has been investigated from photo- and thermally-induced processes. Due to the pitch of cholesteric liquid crystal (CLC) composite increasing as the temperature rises, the CLC with short pitch is frozen by UV-curing the polymer network at low temperature and the CLC with long pitch is fixed by heat curing the polymer network at high temperature. A non-uniform pitch distribution of CLCs forms in the gel when temperature becomes low. It is demonstrated that the memory effect of the polymer network is an important mechanism for the resulting gel. [ABSTRACT FROM AUTHOR]