Thermal properties and crystalline structure of liquid crystalline poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate)

Thermal properties and crystalline structure of liquid crystalline (LC) poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate) [copoly(ET/CPT)] were investigated using differential scanning calorimetry (DSC), thermogravimetry (TGA), limiting oxygen index (LOI) measurement, electron dispersive X‐ray analysis (EDX), X‐ray diffractometry, and infrared spectrometry (IR). The thermal transition temperatures of copoly(ET/CPT) were changed with the composition. Copoly(ET/CPT) showed two thermal decomposition steps and the residues at 700°C and LOI values of copoly(ET/CPT) were almost proportional to its chlorine content. The activation energy of thermal decomposition of LC units was very low compared to that of poly(ethylene terephthalate)(PET) units. Crystal structure of copoly(ET/CPT) (20/80) was of triclinic system with the lattice constants of a = 9.98 A?, b = 8.78 A?, c = 12.93 A?, α = 97.4°, β = 96.1°, and γ = 90.8°, which is very close to that of poly(chloro‐p‐phenylene terephthlate) (PCPT) with the lattice constants of a = 9.51 A?, b = 8.61 A?, c = 12.73 A?, α = 96.8°, β = 95.4°, and γ = 90.8°. When copoly(ET/CPT)(50/50) was annealed at 220°C in vacuum, crystallization induced sequential reordering (CISR) was not observed but the heat of fusion was slightly increased due to the increase of the trans isomer content in PET units. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1286–1294, 2002; DOI 10.1002/app.10451     

Long-wavelength GaInNAs(Sb) lasers on GaAs

The boom in fiber-optic communications has caused a high demand for GaAs-based lasers in the 1.3-1.6-μm range. This has led to the introduction of small amounts of nitrogen into InGaAs to reduce the bandgap sufficiently, resulting in a new material that is lattice matched to GaAs. More recently, the addition of Sb has allowed further reduction of the bandgap, leading to the first demonstration of 1.5-μm GaAs-based lasers by the authors. Additional work has focused on the use of GaAs, GaNAs, and now GaNAsSb barriers as cladding for GaInNAsSb quantum wells. We present the results of photoluminescence, as well as in-plane lasers studies, made with these combinations of materials. With GaNAs or GaNAsSb barriers, the blue shift due to post-growth annealing is suppressed, and longer wavelength laser emission is achieved. Long wavelength luminescence out to 1.6 μm from GaInNAsSb quantum wells, with GaNAsSb barriers, was observed. In-plane lasers from these samples yielded lasers operating out to 1.49 μm, a minimum threshold current density of 500 A/cm² per quantum well, a maximum differential quantum efficiency of 75%, and pulsed power up to 350 mW at room temperature     

Biomimetic engineering of non-adhesive glycocalyx-like surfaces using oligosaccharide surfactant polymers

The external region of a cell membrane, known as the glycocalyx, is dominated by glycosylated molecules, which direct specific interactions such as cell-cell recognition and contribute to the steric repulsion that prevents undesirable non-specific adhesion of other molecules and cells. Mimicking the non-adhesive properties of a glycocalyx provides a potential solution to the clinical problems, such as thrombosis, that are associated with implantable devices owing to non-specific adsorption of plasma proteins. Here we describe a biomimetic surface modification of graphite using oligosaccharide surfactant polymers, which, like a glycocalyx, provides a dense and confluent layer of oligosaccharides. The surfactant polymers consist of a flexible poly(vinyl amine) with dextran and alkanoyl side chains. We show that alkanoyl side chains assemble on graphite through hydrophobic interaction and epitaxial adsorption. This constrains the polymer backbone to lie parallel to the substrate, with solvated dextran side chains protruding into the aqueous phase, creating a glycocalyx-like coating. The resulting biomimetic surface is effective in suppressing protein adsorption from human plasma protein solution.     

Depression in the quantity of intestinal secretory IgA and in the expression of the polymeric immunoglobulin receptor in caloric deficiency of the weanling mouse

Splenomegaly is uncommon in myelodysplasia (MDS) and, although cytopenias may be severe, therapeutic splenectomy is rarely performed. We report the histologic, histochemical, and immunophenotypic findings of nine cases of surgical splenectomy and four postmortem spleens from MDS patients. Four histologic patterns were identified: one dominated by erythrophagocytosis, one characterized by red pulp plasmacytosis, one with extramedullary hematopoiesis as the only salient finding, and one with marked red pulp expansion caused by a monocytic proliferation. Wright-Giemsa and histochemical stains were performed on touch preparations in three cases and played a critical role in the precise subclassification of one MDS patient's hematologic disorder, which ultimately proved to be chronic myelomonocytic leukemia. Splenectomy led to sustained improvement of cytopenias in three cases, but did not eliminate transfusion dependence for the remaining patients. Three splenectomy cases exhibited clustered Leder-negative mononuclear elements: two of these patients experienced disease progression to refractory anemia with excess blasts in transformation or acute myelogenous leukemia during post-splenectomy follow-up, whereas none of the three splenectomy patients without clustered mononuclear elements did. We conclude that splenomegaly in MDS usually reflects the sequelae of dyspoiesis rather than evidence of a proliferative phase, that clustering of Leder-negative large cells may correlate with either a substantial monocytic component or, possibly, increased risk of disease progression, and that the spleen can provide diagnostic as well as prognostic information in MDS patients with splenomegaly.     

Pharmacokinetics and pharmacodynamics of sibrafiban (Ro 48-3657), an orally active IIb/IIIa antagonist, administered alone or in combination with heparin, aspirin, and recombinant tissue-type plasminogen activator in beagles

OBJECTIVE: The study aimed to determine the effectiveness of prophylactic medical intervention in reducing the incidence of cystoid macular edema (CME) and the effectiveness of medical treatment for chronic CME after cataract surgery. DESIGN: The study design was a systematic review and meta-analysis of published reports of randomized clinical trials (RCTs). PARTICIPANTS: Sixteen RCTs involving 2898 eyes examining the effectiveness of medical prophylaxis of CME and 4 RCTs involving 187 eyes testing the effectiveness of medical treatment of chronic CME were used in the study. INTERVENTIONS: Medical prophylaxis of treatment (cyclo-oxygenase inhibitors or corticosteroids) versus control (placebo or active treatment) was performed. MAIN OUTCOME MEASURES: Incidence of angiographically diagnosed CME, incidence of clinically significant CME, and vision were measured. RESULTS: Thirty-six articles reported testing a prophylactic medical intervention for CME after cataract surgery. The incidence of CME varied extensively across studies and was related to the study design used. Summary odds ratios (OR) indicated that prophylactic intervention was effective in reducing the incidence of both angiographic CME (OR = 0.36; 95% confidence interval [CI] = 0.28-0.45) and clinically relevant CME (OR = 0.49; 95% CI = 0.33-0.73). There also was a statistically significant positive effect on improving vision (OR = 1.97; 95% CI = 1.14-3.41). A combination of the results of the four RCTs testing medical therapy for chronic CME indicated a treatment benefit in terms of improving final visual acuity by two or more Snellen lines (OR = 2.67; 95% CI = 1.35-5.30). Assessment of the quality of the 20 RCTs included in the meta-analyses indicated problems in the design, execution, and reporting of a number of trials. CONCLUSION: A combination of the results from RCTs indicates that medical prophylaxis for aphakic and pseudophakic CME and medical treatment for chronic CME are beneficial. Because most of the RCTs performed to date have problems related to quality, a well-designed RCT is needed to confirm this result, using clinical CME and vision as outcomes.     

Gas chromatography in express diagnosis of candidiasis and monitoring of antifungal therapy efficacy by D-arabinitol and mannose levels in pediatric patients]

Methods for preventing and treating Ebola virus hemorrhagic fever are not still available despite the fact that this virus have been studied for 20 years. Methods of immunization of the animals (sheep, goats) non-susceptible to Ebola virus with live virus preparations were developed to obtain the hyperimmune anti-Ebola virus sera required to have highly immune antivirus gamma-globulins. These methods made it possible to obtain the immune sera having high virus-neutralizing antibodies. Caprine immunoglobulins were obtained from sera by fractionation of immune sera by Kohn's method. The neutralization indices of the immunoglobulins obtained were at least Ig. When administered in the first hours of infection, the protective effect of these preparations was shown on guinea pigs infected with LD50 of the strain pathogenic to the animals. Preclinical trials of these immunoglobulins on laboratory animals and clinical trials on volunteers were performed. The preparation was used as a preventive agent when accidents took place at the laboratory working with Ebola virus. The similar preparation from equine sera having high neutralizing and protective properties was elaborated at the Virological Center, Microbiological Institute, Russian Ministry of Defense. Its prophylactic efficiency was also shown in infected gamadrias.     

Systematic relationships of some members of the genera Oesophagostomum and Chabertia (Nematoda: Chabertiidae) based on ribosomal DNA sequence data

The present study characterised seven species of the Chabertiidae (Nematoda: Strongyloidea) belonging to either the subfamily Oesophagostominae (Oesophagostomum radiatum, Oesophagostomum venulosum, Oesophagostomum dentatum, Oesophagostomum quadrispinulatum, Oesophagostomum columbianum, Oesophagostomum bifurcum) or to the subfamily Chabertiinae (Chabertia ovina) by their second internal transcribed spacer rDNA sequence, assessed the extent of intraspecific variation and interspecific differences in the sequence, and inferred the phylogenetic relationship of C. ovina with respect to members of the Oesophagostominae. In both the phenetic and cladistic analyses of the sequence data, Chabertia was nested within Oesophagostomum, suggesting either that the species examined represent members of the same genus, or alternatively, that Oesophagostomum may represent more than one genus.     

Hyperpolarization induces a rise in intracellular sodium concentration in dopamine cells of the substantia nigra pars compacta

We investigated the effect of changes in membrane-voltage on intracellular sodium concentration ([Na+]i) of dopamine-sensitive neurons of the substantia nigra pars compacta in a slice preparation of rat mesencephalon. Whole-cell patch-clamp techniques were combined with microfluorometric measurements of [Na+]i using the Na+-sensitive probe, sodium-binding benzofuran isophthalate (SBFI). Hyperpolarization of spontaneously active dopamine neurons (recorded in current-clamp mode) caused the cessation of action potential firing accompanied by an elevation in [Na+]i. In dopamine neurons voltage-clamped at a holding potential of -60 mV elevations of [Na+]i were induced by long-lasting (45-60 s) voltage jumps to more negative membrane potentials (-90 to -120 mV) but not by corresponding voltage jumps to -30 mV. These hyperpolarization-induced elevations of [Na+]i were depressed during inhibition of I(h), a hyperpolarization-activated inward current, by Cs+. Hyperpolarization-induced elevations in [Na+]i might occur also in other cell types which express a powerful I(h) and might signal lack of postsynaptic activity.     

Extrinsic calibration of a camera and laser range finder using a new calibration structure of a plane with a triangular hole

Sensor fusion of a camera and laser range finder is important for the autonomous navigation of mobile robots. Finding the transformation between the camera and laser range finder is the first necessary step for the fusion of information. Many algorithms have been proposed, but these tend to require many different steps in order to achieve reliable and accurate results. A calibration structure that has triangular hole on its plane is proposed for the extrinsic calibration of a camera and laser range finder. Locations of laser scan data that are invisible on the calibration plane can be determined using property on the proposed calibration structure. First, we classify the laser scan data into two groups where one is on the plane and the other is off the plane. Then, we determine the absolute location of the laser scan data on the plane through a search of the parameters of the line. Finally, we can establish 3D-3D correspondences between the camera and laser range finder. Extrinsic calibration between a camera and laser range finder is found using a conventional 3D-3D transformation computing algorithm. Keywords: Calibration k]camera k]extrinsic calibration k]laser range finder     

A study on the dynamic characteristics of the Korean Yi-dynasty bell type structure

The dynamic characteristics of the Korean Yi-dynasty bell type structure, including the acoustic effects, are analyzed both theoretically and experimentally. The numerical solutions of natural frequencies and mode shape for membrane and flexural behavior are obtained by using the NASTRAN program for the finite element method with plate shell elements of triangular and quadrilateral types. Test bells, A and B types similar to the Kap-Sa bell in Kong-Ju chosen among typical Korean Yi-dynasty bells, are manufactured on different scales to the original bell. To consider the effects of the variation of the structural dimension on the dynamic response, these bells are analyzed with respect to the variation of the thickness of the wall and the bottom rim and the asymmetric Dang-Jwas. The impact method with the Fast Fourier Transform Analyzer is adopted to experimentally assess the dynamic response. Results are in good agreement with the numerical solutions.