Scalar quantisation of LSF parameters using vector measurement

A new form of line spectral frequency (LSF), bounded line spectral frequency, is presented. It is shown that the new representation is more efficient than the direct line spectral frequency and the differential line spectral frequency (DLSF). By using a vector measure, the scalar quantisation of tenth-order linear predictive coding (LPC) parameters can be coded at 28 bit/frame with a transparent quantisation quality     

Pancreaticoduodenectomy for selected periampullary neuroendocrine tumors: fifty patients

BACKGROUND: Most resectable pancreatic or peripancreatic neuroendocrine tumors are treated by enucleation or distal pancreatectomy. A minority of tumors may require pancreaticoduodenectomy for complete tumor excision because of their large size, location, or lymph node involvement. METHODS: This study reviews the management of 50 patients treated by pancreaticoduodenectomy for periampullary neuroendocrine tumors between 1962 and 1996 at a single institution. RESULTS: There were 30 men and 20 women with a mean age of 52 +/- 2 years. Functional tumors were resected in 17 patients: insulinoma, seven tumors; gastrinoma, eight tumors; vipoma, one tumor; and glucagonoma, one tumor. Tumors were classified as malignant in 29 patients and benign in 21. The median intraoperative blood loss was 800 ml, and the median number of units of blood transfused was zero. The postoperative length of stay was 20 +/- 2 days. Postoperative morbidity included 11 patients (24%) with a pancreatic fistula and four patients (8%) with a biliary fistula. There was one in-hospital death (2%), in 1967. The actuarial survival rates at 2, 5, and 7 years are 81%, 73%, and 65%, respectively. Patients with benign tumors had a significantly improved 5-year survival rate (94%) compared with those with malignant tumors (61%; p = 0.03). CONCLUSIONS: Selected patients with periampullary neuroendocrine tumors can be managed successfully by pancreaticoduodenectomy, with low mortality and acceptable morbidity rates.     

Variants of chromosome 9 in phenotypically normal individuals

The human chromosome 9 displays the highest degree of structural variability. Four different types of variants are described including pericentric inversion, extra G-positive band in the q arm, additional G-positive band in the p arm and duplication of band 9q21-q22. It is important to demonstrate inheritance from a phenotypically normal individual in order to differentiate between a variant chromosome and an abnormal chromosome.     

Improved strained HEMT characteristics using double-heterojunctionIn0.65Ga0.35As/In0.52Al0.48As design

The DC and microwave properties of strained In_0.65Ga _0.35As/In₀₅₂Al_0.48As HEMTs (high electron-mobility transistors) with double-heterojunction design are presented. The high sheet carrier density and good carrier confinement give rise to excellent device performance with very low output conductance. For 1×150-μm² long-gate HEMTs, the measured cutoff frequency f_T and maximum frequency of oscillation f_max are as high as 37 and 66 GHz, respectively     

Determination of alpha-particle track depths in CR-39 detector from their cross-sections and replica heights

A challenging task in the application of solid-state nuclear track detectors (SSNTDs) is the measurement of depths of the tracks. One approach involves breaking and polishing the side of SSNTDs to reveal the cross-sections of the tracks for direct measurements. Recently, surface profilometry was used to measure the heights of the replicas of alpha-particle tracks to give the track depths. In the present work, systematic comparisons among the track depths for alpha-particles with normal incidence and different incident energies were made for these two methods. After irradiation, the detectors were etched in a 6.25 N aqueous solution of NaOH at 70 °C. Both long etching time of 15 h (to produce spherical-phase tracks) and short etching time from 1 to 8 h (to produce sharp-phase tracks) were used. Good agreement was achieved between the two methods for spherical-phase tracks but not for sharp-phase tracks. It has been found that the surface profilometry method only works for replicas for spherical-phase tracks. Replicas for sharp-phase tracks are easier to collapse or deform, so the surface profilometry method may not give correct results.     

The effectiveness of ovarian cancer screening. A decision analysis model

OBJECTIVE: To estimate the effectiveness of ovarian cancer screening with CA 125 and transvaginal sonography. DESIGN: Decision analysis was used to examine the no-screen compared with the screen strategy. SETTING: Estimates of cancer incidence, survival, and life expectancy were derived from population-based data and clinical series. SUBJECTS: A cohort of 40-year-old women of all races and residing in the United States. INTERVENTIONS: A one-time screening intervention. The criterion standard for diagnosis of ovarian cancer was evaluation with exploratory laparotomy. MAIN OUTCOME MEASURE: Average years of life expectancy gained by women in the screened group. RESULTS: Screening for ovarian cancer with a combination of CA 125 and transvaginal sonography increases the average life expectancy in the population by less than 1 day. CONCLUSIONS: Given the limited effect on overall life expectancy, it is unlikely that mass screening for ovarian cancer with CA 125 and transvaginal sonography would be an effective health policy.     

Optical appearance of alpha particle tracks in CR-39 SSNTD

A ray tracing method based on geometrical optics was used to study the tracks from alpha particles with different energies and with an incident angle of 50°. The transmission operation mode of the microscope is simulated. Considering the distribution of light intensities from the tracks, the mean and the 80% percentile gray levels from real experiments are proposed as quantitative variables to differentiate among tracks. The gray level properties for the same track for different exposures can vary to large extents. We introduce three variables, κ, λ and ε, to make empirical corrections. It is interesting to see that these coefficients are very consistent for the same alpha particle track despite the very different gray level properties. Gray level results have been obtained for tracks from alpha particles with 50° incident angle and different incident energies. However, the track depths cannot be predicted by any one of the coefficients κ, λ and ε. Multivariate analyses can help separate the tracks corresponding to different alpha energies. By using discriminant analysis with κ, λ and ε as independents, effectively all alpha energies can be determined with an accuracy of ±0.5 MeV.     

Short-term handling of the slimming agent oleoyl-estrone in liposomes (Merlin-2) by the rat

Female adult rats were injected in the jugular vein with oleoyl-3H-estrone incorporated into liposomes. The label rapidly disappeared from the blood, being taken up by the tissues, mainly liver, spleen and lung, which filtered most of the label. However, many other tissues, such as the heart, brown adipose tissue, adrenals and visceral fat incorporated significant amounts of oleoyl-estrone. The analysis of the form in which the label remained 10 min after the injection showed that it was hydrolysed in a large proportion even in liver and lungs. However, in most tissues (brain, brown and white - periovaric - adipose tissues and ovaries), intact oleoyl-estrone accounted for less than one quarter of all tissue label, and less than 10% in the case of subcutaneous adipose tissue and uterus. This rapid destruction of oleoyl-estrone is in agreement with the active role of this compound in the control of body weight.     

Distribution of alpha 1A, alpha 1B and alpha 1E voltage-dependent calcium channel subunits in the human hippocampus and parahippocampal gyrus

The distribution of voltage-dependent calcium channel subunits in the central nervous system may provide information about the function of these channels. The present study examined the distribution of three alpha-1 subunits, alpha 1A, alpha 1B and alpha 1E, in the normal human hippocampal formation and parahippocampal gyrus using the techniques of in situ hybridization and immunocytochemistry. All three subunit mRNAs appeared to be similarly localized, with high levels of expression in the dentate granule and CA pyramidal layer. At the protein level, alpha 1A, alpha 1B and alpha 1E subunits were differentially localized. In general, alpha 1A-immunoreactivity was most intense in cell bodies and dendritic processes, including dentate granule cells, CA3 pyramidal cells and entorhinal cortex pre-alpha and pri-alpha cells. The alpha 1B antibody exhibited relatively weak staining of cell bodies but stronger staining of neuropil, especially in certain regions of high synaptic density such as the polymorphic layer of the dentate gyrus and the stratum lucidum and radiatum of the CA regions. The alpha 1E staining pattern shared features in common with both alpha 1A and alpha 1B, with strong immunoreactivity in dentate granule, CA3 pyramidal and entorhinal cortex pri-alpha cells, as well as staining of the CA3 stratum lucidum. These findings suggest regions in which particular subunits may be involved in synaptic communication. For example, comparison of alpha 1B and alpha 1E staining in the CA3 stratum lucidum with calbindin-immuno-reactivity suggested that these two calcium channels subunits may be localized presynaptically in mossy fibre terminals and therefore may be involved in neurotransmitter release from these terminals.     

795 nm and 1064 nm dual pump thulium-doped tellurite fibre for S-band amplification

Gain measurement in thulium-doped tellurite fibre is demonstrated with a maximum internal gain of 7 dB at 1480 nm. An improvement in gain by a factor of 2 is achieved using a 795 nm and 1064 nm dual pump scheme. Gain in tellurite fibres extends to longer wavelength than in fluorides, showing improved overlap with the C-band EDFA.