Liquid-crystalline phase development of a mesogen-jacketed polymer-application of two-dimensional infrared correlation analysis.

Two-dimensional correlation spectroscopy has been applied to study PMPCS (poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene}), a representative example of mesogen-jacketed liquid crystalline polymers. With the precise analysis of a series of Fourier transform infrared (FTIR) spectra of PMPCS recorded at varied temperatures, a reasonable mechanism of the development of liquid crystalline (LC) phase is proposed. Before the phase transition, the conformational change of individual side chains occurs sooner than that of the backbone due to the larger motional freedom of the side chains.

Low-loss tunable filter based on optical rotatory dispersion.

The optical arrangement of a spectral filter without an intermediate polarizer that was developed based on optical rotatory dispersion and test measurement results are presented and described. The filter uses three dispersive polarization rotators as the key elements in combination with two additional quarter-wave retarders, and it is wavelength tunable with a spectral transmission equivalent to that of a standard Lyot two-stage filter.

Independent origin of the growth hormone gene family in New World monkeys and Old World monkeys/hominoids.

The growth hormone (GH) gene family represents an erratic and complex evolutionary pattern, involving many evolutionary events, such as multiple gene duplications, positive selection, the birth-and-death process and gene conversions. In the present study, we cloned and sequenced GH-like genes from three species of New World monkeys (NWM). Phylogenetic analysis strongly suggest monophyly for NWM GH-like genes with respect to those of Old World monkeys (OWM) and hominoids, indicating that independent gene duplications have occurred in NWM GH-like genes.

Orthologous repeats and mammalian phylogenetic inference.

Determining phylogenetic relationships between species is a difficult problem, and many phylogenetic relationships remain unresolved, even among eutherian mammals. Repetitive elements provide excellent markers for phylogenetic analysis, because their mode of evolution is predominantly homoplasy-free and unidirectional. Historically, phylogenetic studies using repetitive elements have relied on biological methods such as PCR analysis, and computational inference is limited to a few isolated repeats.

Frustrated molecular packing in highly ordered smectic phase of side-chain liquid crystalline polymer with rigid polyacetylene backbone.

Using poly(5-{[(4'-heptoxy-4-biphenylyl)carbonyl]oxy}-1-pentyne) as an example, we demonstrate the incorporative accommodation of the rigid polyacetylene backbones and the mesogenic pendants, which leads to a highly ordered smectic (Sm) phase with a frustrated structure. The polymer exhibits a recognizable sheetlike molecular shape due to its rigid backbone and relatively short spacer (three methylene units), and the building block of the liquid crystalline (LC) phase is the whole molecule. In the LC phase, five layers of the molecules stack as a smectic A (SmA) block, and adjacent SmA blocks glide halfway of the molecular width from one to another.

[Ecological restoration and reconstruction of degraded lakeside zone ecosystem].

As a kind of aquatic-terrestrial ecotone, lakeside zone plays an important role in the lake basin ecosystem, and has high ecological, social and economic values. Its functions include lake buffer, conservation of biological diversities and special habitats, dike protection from soil erosion, and economic and esthetics values. The main factors inducing lakeside zone degradation are the anthropogenic activities that caused the converse succession of communities and the decline of ecological function.

Molecular evolution of growth hormone gene family in old world monkeys and hominoids.

Growth hormone is a classic molecule in the study of the molecular clock hypothesis as it exhibits a relatively constant rate of evolution in most mammalian orders except primates and artiodactyls, where dramatically enhanced rate of evolution (25-50-fold) has been reported. The rapid evolution of primate growth hormone occurred after the divergence of tarsiers and simians, but before the separation of old world monkeys (OWM) from new world monkeys (NWM). Interestingly, this event of rapid sequence evolution coincided with multiple duplications of the growth hormone gene, suggesting gene duplication as a possible cause of the accelerated sequence evolution.

[Detection and typing for swine leukocyte antigen].

Traditionally the cluster of swine leukocyte antigen (SLA) was typed by serological, cytological and biochemical methods. Many special molecular typing methods have been developed with the progress of molecular biological technology, such as PCR-RFLP, PCR-SSCP , MS and DNA sequencing. Here we discussed the advantages and disadvantages of each method based on the polymorphic and conservative (from the functional aspect, such as supertype and supermotif) characteristics of SLA, and illustrated the development of typing for SLA in the future.

[Cloning of novel pituitary growth hormone gene from Rhinopithecus roxellanae].

Putative pituitary growth hormone gene of Rhinopithecus roxellanae was cloned and sequenced. All exons sequences and deduced amino acid sequence (containing 26 residues signal peptide and 191 residues mature protein) were obtained. We constructed a phylogenetic tree,which well reflected the true evolutionary relationship of pituitary growth hormone genes from 7 primates species.

Assessing computational tools for the discovery of transcription factor binding sites.

The prediction of regulatory elements is a problem where computational methods offer great hope. Over the past few years, numerous tools have become available for this task. The purpose of the current assessment is twofold: to provide some guidance to users regarding the accuracy of currently available tools in various settings, and to provide a benchmark of data sets for assessing future tools.

Liquid-crystal bandpass filter based on the optical rotatory dispersion effect.

A bandpass spectral filter and the test measurement results are presented and described. The filter is developed and constructed by use of a ferroelectric liquid-crystal polarization rotator in combination with dispersive quartz optical rotators, and its wavelength selection is mechanically tunable and electrically switchable.

Clinical analysis of uncinate process carcinoma of the pancreas.

Objective: To analyse the clinical features of uncinate process carcinoma of the pancreas and the diagnosis and treatment of this malignancy.

Method: Fifty-nine patients with pancreas uncinate process carcinoma treated from January 1998 to September 2002 at our hospital were analysed retrospectively.

Results: Major symptoms of these patients were upper abdominal pain accompanied with lumbar pain, body weight loss and jaundice.

Wavelength-tunable spectral filters based on the optical rotatory dispersion effect.

An optical arrangement for constructing wavelength-tunable spectral filters is presented that makes use of a set of dispersive polarization rotations to select wavelengths. A filter in the arrangement is initially mechanically tunable, requires no achromatic retarder, and can be further electrically tunable, switchable, or both, depending on the elements selected. Test measurements and results are presented and described.

Manipulating supramolecular self-assembly via tailoring pendant group size of linear vinyl polymers.

In a series of poly[di(alkyl) vinylterephthalates] (PDAVTs) synthesized via radical polymerization, fine-tuning the size and shape of the side groups manipulated the supramolecular self-assembly and led to control over the formations between amorphous and 2D ordered hexagonal phases. To introduce the 2D long-range ordered structure, the size of the ester side groups at the 2- and 5-positions of the phenyl rings laterally attached to the backbones had to be in the range of propyl/isopropyl to hexyl. The relatively extended backbones observed in these polymers were attributed to steric effects from the side groups.

Development of a polymer bileaflet valve to realize a low-cost pulsatile blood pump.

The final goal of this study is to realize a low-cost pulsatile blood pump especially for patients with acute heart failure or postoperative low cardiac output syndrome. In support of the pump, two types of polymer bileaflet valves with different configuration of the valve seats were developed. Influence of the leaflet thickness on the hydrodynamics of the prototype was preliminarily investigated among 70 microm, 100 microm, and 150 microm.

[Uncinate process carcinoma of the pancreas: clinical features and diagnosis and treatment].

Objective: To summarize the clinical features and diagnosis and treatment of uncinate process carcinoma of the pancreas.

Methods: From January 1998 to December 2000, 41 patients of pancreas uncinate process carcinoma were retrospectly analysed.

Results: Upper abdominal pain accompanied with back pain,weight loss and jaundice were the main symptoms.