Depression among cancer patients

OBJECTIVE: To identify important causes of premature mortality among Aboriginal adults in the Northern Territory (NT), 1979-1991. METHODS: All deaths of NT Aboriginal residents aged 15-64 years which occurred in the NT between 1979 and 1991 and which were recorded by the Registry of Births, Deaths and Marriages were included. Standardised mortality ratios (SMRs) were used to compare the number of deaths observed among Aboriginals in the NT to those expected, based on overall Australian rates. Years of potential life lost before age 65 (YPLL65) were estimated for specific causes of death. RESULTS: Aboriginal women (overall SMR, 5.5) and Aboriginal men (SMR, 4.7) experienced a high burden of excess mortality from almost every cause of death. This excess increased over time, especially for Aboriginal women. Among Aboriginal men, the most important causes of premature death were motor vehicle accidents (11% of excess deaths and 17% of YPLL65), ischaemic heart disease (10% of excess deaths and 10% of YPLL65), pneumonia and influenza (8% of excess deaths and 6% of YPLL65), and homicide (7% of excess deaths and 8% of YPLL65). For Aboriginal women, the most important causes included homicide (7% of excess deaths and 11% of YPLL65), chronic obstructive pulmonary disease (10% of excess deaths and 5% of YPLL65), rheumatic heart disease (7% of excess deaths and 8% of YPLL65), and ischaemic heart disease (6% of excess deaths and 5% of YPLL65). CONCLUSIONS: The wide variety of causes of excess mortality will require an equally wide variety of solutions, both medical and non-medical, and a long term commitment will be necessary to achieve reductions in premature mortality among NT Aboriginal adults.     

Dynamic analysis of cracked linear viscoelastic solids by finite element method using singular element

The finite element method for the dynamic problem of cracked linear viscoelastic solids is developed using the singular element where the displacement function is taken from the analytical solution near the crack-tip. The time variation of the dynamic stress intensity factors is determined for a center crack and an oblique crack in standard linear viscoelastic rectangular plates subjected to dynamic loading.

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Résumé La méthode par éléments finis permettant d'aborder le problème dynamique des solides linéaires viscoélastiques fissurés est développée en recourant à un élément singulier pour lequel la fonction de déplacement est prise dans une solution analytique au voisinage del'extrémité de la fissure. La variation dans le temps des facteurs d'intensité de contrainte dynamique est déterminée pour une fissure centrale et pour une fissure oblique dans des plaques rectangulaires standard en matériau linéaire viscoélastique soumises à une sollicitation dynamique.

     

The indirect hemagglutination test for onchocerciasis performed with blood collected on filter paper

In Guatemala, an indirect hemagglutination (IHA) test for onchocerciasis, performed with a crude saline extract of Onchocerca volvulus and blood samples taken on filter paper, showed a high level of sensitivity and specificity. IHA titers of blood samples from the ear lobe taken on filter paper and of sera obtained by venipuncture showed a high correlation.     

Optimal discrete-time control system with cost for observation

The problem of how to select the total number and the spacings of the observations optimally when a constant cost is incurred for each observation taken is discussed. Approximate expressions for the criterion function with a fixed number of observations are obtained and are used to determine the optimal total number of observations. For a class of multidimensional systems with a dominant eigenvalue, the problem is shown to reduce to that for scalar systems. Detailed discussion is then carded out for scalar systems including some sensitivity study.     

Changes in flagellar bending during the course of hyperactivation in hamster spermatozoa

The motility pattern of mammalian spermatozoa changes during migration in the female genital tract and during incubation in vitro. This change in motility is termed hyperactivation. Hyperactivated spermatozoa swim vigorously in 'whiplash', 'figure-8' or 'small circle' trajectories. In this study, a quantitative analysis was carried out of the changes in the motility pattern of hamster spermatozoa during incubation to investigate the mechanism regulating hyperactivation. In the culture system used in this study, hyperactivation occurred 4 h after incubation. Several parameters in the analysis of sperm movement pattern were examined. Curvilinear velocity, average path velocity and straightness abruptly increased between 2 and 4 h. However, linearity, amplitude of lateral head displacement, beat cross frequency and average wavelength gradually changed with time. In the analysis of flagellar bending, the bend angles were measured after dividing images of the flagellum into short lengths. Flagellar bending changed in different manners in each region during incubation. The asymmetry in the direction of the curve of the head gradually increased with time in the first half of the flagellum. The flexibility, which was determined using the amplitude of bending and the rate of change in bend angles, abruptly decreased between 10 min and 1 h, and then increased between 2 and 4 h in the first half of flagellum. These results indicate that complex physiological changes occur before hyperactivation.     

Characterization of polymer-adhesive interfaces on a nanometre scale by elemental mapping and image EELS using EFTEM

Energy-filtering transmission electron microscopy (EFTEM) was applied for investigating interfaces between a polymer and an adhesive. The sample employed in this work is polybutylene terephtharate (PBT) sheets laminated with an epoxy adhesive. It was found that heat aging of the PBT at 180 degrees C in air for > 9 h prior to adhesion decreases the adhesion strength drastically. To investigate this unfavourable aging effect on the adhesion strength, we performed elemental mapping and image EELS using EFTEM. A weak boundary layer with a thickness of < 50 nm was visualized at the PBT-adhesive interface by elemental mapping in the sample subjected to the heat aging and image EELS revealed the origin of this layer. Thus, we clearly correlated the nanoscale interfacial structure with the adhesion strength by EFTEM.     

The study of metal ion release and cytotoxicity in Co–Cr–Mo and Ti–Al–V alloy in total knee prosthesis – scanning electron microscopic observation

We surgically retrieved two cobalt(Co)–chromium(Cr)–molybdenum(Mo) and five titanium(Ti)–aluminum(Al)–vanadium(V) alloy knee prostheses from patients because of mechanical failure and pain. We examined the distribution of the small particles which were released from the Co–Cr–Mo and Ti–Al–V alloys using a backscattered scanning electron microscopy (SEM). In addition we analyzed the metals in the artificial knee joints and the tissues adjacent to them using energy dispersive X-ray spectroscopy (EDS). We demonstrated that a myriad of fine particles, produced by the abrasion of both Co–Cr–Mo and Ti–Al–V alloys, accumulated in the synovial cells. As Co–Cr–Mo alloys disintegrate easily in the cells, Co dissolves from the peripheral areas of them, although Cr remains within the cells. In contrast Ti–Al–V alloys are very stable in the synovial cells. From these findings we conclude that the Co–Cr–Mo alloys are hazardous to the body as the alloys release Co which enters the body. In contrast the Ti–Al–V alloys are very stable and are patently safer. Artificial joints, however, are still in considerable need of improvement.     

Microassembly of semiconductor three-dimensional photonic crystals

Electronic devices and their highly integrated components formed from semiconductor crystals contain complex three-dimensional (3D) arrangements of elements and wiring. Photonic crystals, being analogous to semiconductor crystals, are expected to require a 3D structure to form successful optoelectronic devices. Here, we report a novel fabrication technology for a semiconductor 3D photonic crystal by uniting integrated circuit processing technology with micromanipulation. Four- to twenty-layered (five periods) crystals, including one with a controlled defect, for infrared wavelengths of 3-4.5 microm, were integrated at predetermined positions on a chip (structural error <50 nm). Numerical calculations revealed that a transmission peak observed at the upper frequency edge of the bandgap originated from the excitation of a resonant guided mode in the defective layers. Despite their importance, detailed discussions on the defective modes of 3D photonic crystals for such short wavelengths have not been reported before. This technology offers great potential for the production of optical wavelength photonic crystal devices.     

Optical Burst Switching Router With 40-,10-Gb/s Bit-Rate Transparent Contention Resolution

We report a bit-rate transparent optical burst switching (OBS) router prototype using a fast 5 times 5 PLZT [(Pb,La)(Zr,Ti)O₃ ] optical matrix switch. Dynamic switching in a two-wavelength, 2 times 2 OBS switch is demonstrated. Contention resolution using a tunable Mach-Zehnder interferometer wavelength converter for both 40- and 10-Gb/s bursts is demonstrated for the first time. Error-free operation was achieved for both bit rates under the same settings, as required in autonomous networks