High-Power and Widely Tunable All-Fiber Raman Laser

A high-power and widely tunable all-fiber Raman laser is demonstrated. The Raman fiber laser has been tuned over a range of 60 nm from 1075 to 1135 nm and delivers up to 5.0 W of Stokes output power for 6.5 W of launched pump power. Efficiencies ranging from 76.1 to 93.1% and laser thresholds from 0.78 to 2.59 W have been measured. The spectrum of the depolarized Raman gain coefficient of the germanosilicate fiber has also been inferred from our experimental measurements.     

In Vivo Cell Tracking With Video Rate Multimodality Laser Scanning Microscopy

Studies of biological processes, such as disease progression and response to therapy, call for live imaging methods that allow continuous observation without terminating the study subject for histological tissue processing. Among all current imaging modalities, optical microscopy is the only method capable of probing live tissue with cellular and subcellular resolution. We present a video-rate (30 frames/s), multimodality imaging system that is designed specifically for live animal imaging and cell tracking. In vivo depth-sectioned, high-resolution images are obtained using confocal and nonlinear optical techniques that extract structural, functional, and molecular information by combining multiple contrast mechanisms, including back scattering, fluorescence (from single- and two-photon excitation), second harmonic generation, and coherent anti-Stokes Raman scattering. Simultaneous use of up to three modalities is possible and eliminates the need for coregistration, especially on large-scale images. A real-time movement correction algorithm was developed to extend integration times in cases where the image needs to be stabilized against subject movement. Finally, imaging of fast moving leukocytes in blood vessels is made possible with a modification that permits operation at 120 frames/s over a smaller area. Sample imagery obtained in vivo with the microscope is presented to illustrate the capabilities.     

An efficient computation-constrained block-based motion estimationalgorithm for low bit rate video coding

We present an efficient computation constrained block-based motion vector estimation algorithm for low bit rate video coding that yields good tradeoffs between motion estimation distortion and number of computations. A reliable predictor determines the search origin, localizing the search process. An efficient search pattern exploits structural constraints within the motion field. A flexible cost measure used to terminate the search allows simultaneous control of the motion estimation distortion and the computational cost. Experimental results demonstrate the viability of the proposed algorithm in low bit rate video coding applications. The resulting low bit rate video encoder yields essentially the same levels of rate-distortion performance and subjective quality achieved by the UBC H.263+ video coding reference software. However, the proposed motion estimation algorithm provides substantially higher encoding speed as well as graceful computational degradation capabilities.     

Postmenopausal estrogen use and Parkinson''s disease with and without dementia

Transmyocardial laser revascularization is an emerging technique for treatment of patients with coronary artery disease not amenable to standard revascularization by either percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. Transmyocardial laser revascularization is typically performed as an isolated procedure on the beating heart, although it has been performed as an adjunct to conventional coronary artery bypass grafting in nongraftable territories. We report the use of transmyocardial laser revascularization in combination with mitral valve replacement via a left lateral thoracotomy for treatment of ischemic mitral regurgitation.     

Composition and interfacial activity of hydrophobic sulphide-type extractants

The composition and interfacial activity of dihexyl sulphide (Elf), dodecyl methyl sulphide (two samples from Elf and Penwalt) and n-dodecyl hydroxyethyl sulphide (Elf) which are commercially available sulphide-type extractants have been investigated. Recrystallized n-dodecyl hydroxyethyl sulphide was found to be of high purity (i.e. impurities, if any, are below the detection level of a gas chromatograph equipped with an efficient capillary column), whereas it was shown that all the other sulphides contained many components which were separated and, for most of them, indentified by a GC/MS technique. Recrystallized n-dodecyl hydroxyethyl sulphide starts to adsorb at the 2 M HCI/dodecane interface at concentrations (typically 10^?3 M ) of about one order of magnitude lower than dodecyl methyl sulphide (Elf or Penwalt). Dihexyl sulphide exhibits a very weak interfacial activity and the observed decrease in the interfacial tension in the system containing about 0·4 M dihexyl sulphide cannot be attributed with certainty to its own interfacial activity.     

Conformational and biological properties of a covalently linked dimer of glucagon. Reaction of mono- and bifunctional sulfenyl halides

The tryptophan residue of glucagon was modified by reaction with a mono-functional sulfenyl chloride (2-nitrophenylsulfenyl chloride) and with a bifunctional sulfenyl chloride (2,4-dinitro-1,5-phenyldisulfenyl chloride) to produce a monomeric form of glucagon with a modified tryptophan, glucagon-nitrophenylsulfenyl and a dimeric form (glucagon)2-dinitrophenyldisulfenyl respectively. The dimeric form was isolated by chromatography on Sephadex G-50. The circular dichroism spectra of pH and low temperature. The derivatives activated adenylate cyclase from rat liver to an extent comparable to that of the native hormone, indicating that a glucagon dimer is capable of biological activity and that an intact tryptophan residue is not essential for biological response.     

Complexes of starch polysaccharides and poly(ethylene co-acrylic acid): Structural characterization in the solid state

The structural characterization of model complexes of amylose (AM) and amylopectin (AP) with poly(ethylene-co-acrylic acid) (EAA) was undertaken in order to better understand the interactions that occur between the polysaccharides and EAA in starch-EAA-polyethylene films. X-ray diffraction and CP/MAS ¹³C-NMR studies showed that precipitates from solution mixtures of AM and EAA form crystalline, helical V -type inclusion complexes. The proportion of AM forming the V -type complex in the EAA/AM blends, estimated from shifts in the C1 resonance of AM, increased with increasing EAA/AM ratio, reaching a value of about 80% at EAA/AM = 0.5 (w/w). Similar measurements for EAA/AP complexes showed < 10% V structure. Approximately 80% of the AM and 4% of the AP in these blends was resistant to amylase digestion, in good agreement with their V -structure contents as determined above. Resonances at 184 and 181 ppm were observed for the carboxyl carbon of EAA in the EAA/AM and EAA/AP complexes. The resonance at 181 ppm, which was not observed in pure EAA, probably reflects greater shielding of the carboxyl inside the polysaccharide helix as well as changes in hydrogen bonding. The intensity of this peak was 2–3 times larger for the EAA/AM than for the EAA/AP complexes. FTIR experiments suggest that most (> 50%) of the EAA carboxyl groups were hydrogen bonded to polysaccharide hydroxyl groups in both AM and AP complexes when EAA/polysaccharide < 1.     

“Blind” shape reconstruction from experimental data

A method for reconstructing the shape of a bounded impenetrable object from measured scattered field data is presented. The reconstruction algorithm is, in principle, the same as that used before for reconstructing the conductivity of a penetrable object and uses the fact that for high conductivity the skin depth of the scatterer is small, in which case the only meaningful information produced by the algorithm is the boundary of the scatterer. A striking increase in efficiency is achieved by incorporating into the algorithm the fact that for large conductivity, the contrast is dominated by a large positive imaginary part. This fact together with the knowledge that the scatterer is constrained in some test domain constitute the only a priori information about the scatterer that is used. There are no other implicit assumptions about the location, connectivity, convexity, or boundary conditions. The method is shown to successfully reconstruct the shape of an object from experimental scattered field data in a “blind” test     

Extraction of chromium (III) from spent tanning baths

Extraction of chromium(III) from a model spent tanning bath of the leather industry has been investigated using ammoniated and non-ammoniated di(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex® 272). Chromium extraction of 95% by 15% (v/v) D2EHPA, 10% (v/v) isodecanol in kerosene and 86.1% by 15% (v/v) Cyanex® 272, 10% (v/v) p-nonylphenol in kerosene was obtained at equilibrium pH values of 4.0 and 5.0, respectively. The separation of small amounts of iron (III) and aluminium (III) present in the solution along with the Cr(III), was also examined and it was found that Cyanex® 272 was a better reagent than D2EHPA. The slow kinetics of extraction and stripping observed in the case of AI(III) was advantageous for its separation from Fe(III) at low pH values. Difficulties faced in the stripping of loaded metals were also studied because only about 80% chromium recovery by 8 M HCl was obtained from both solvents. The incomplete stripping of the metal may be a result of the formation of a stable species in the organic phase and needs further investigation. The Cr(III) can be recovered as chloride from the strip liquor and recycled for retanning purposes.     

Are the postures adopted according to requested linguistic categories similar to those classified by the recording protocols?

Knowledge on how workers perceive and associate their postures for trunk flexion with respect to linguistic categories, could allow for the development of simple and valid instruments for self-assessment and for more effective postural training. Considerable time and expense could be saved if reliable self-assessments were available. This study describes the anterior flexion angles of the trunk adopted by individuals according to linguistic categories (mild, moderate and severe) and registered by photograph. The postures were compared with postural recording protocols. Twenty sedentary individuals (10 male and 10 female) and 12 industrial female workers (6 healthy and 6 low back sufferers) participated. Subjects were capable of discriminating linguistic postural categories, since they adopted different trunk postures when distinct categories were requested (p< 0.0001). However, the individual variability was high for each category estimated. This could explain, at least in part, the low level of agreement between self-assessment and observational studies.