Assessment of the diagnostic system of Schistosoma infection at rural health unit level, Egypt.

The study sample was 6 rural health units and 405 attendants. Assessment of inputs was done through review of documents, charts, interviews, questionnaires and direct observation. Assessment of accuracy of the techniques was done by cross matching the results of urine and stools examination using different techniques (filtration and sedimentation for urine, and Kato-Katz and direct smear for stools). Results of technicians were compared with that of investigators using the same technique. Two days examinations of urine and stools samples were done by investigators using nucleopore and Kato-Katz, respectively. Environment assessment showed that, political and economic environments were the most influencing components that affect the system of diagnosis. Organization assessment showed that organization structure adapted to a large extent its objectives. However, decentralization and technological development were required. Filtration was more sensitive than sedimentation (82% and 51.3%, respectively). Specificity and PV+ were 100% for both tests. While, PV- and efficiency were 97.6% and 97.8% for filtration, and 93.7% and 94.1% for sedimentation, respectively. Sensitivity of Kato-Katz was higher than direct smear (88.5% and 11.5%, respectively). Kappa coefficient ranged between 0.63 and 1 as regards results of technicians compared to that of investigators. Mean daily workload of urinary examinations per technician ranged between 5.8 and 34.8. That of stools examinations was 5.3 and 32.4. Satisfaction rates ranged between 51.3% and 100% for different rural health units. Strengths and opportunities should be intensified. Weaknesses and threats should be treated.

Second International Topical Meeting on photoacoustic spectroscopy: an introduction.

The Second International Topical meeting on photoacoustic spectroscopy is introduced, and tacoustic effect is briefly described.

Photothermal spectroscopy of scattering media.

We present a general unified theoretical analysis of the role of scattering in photothermal spectroscopy, e.g., photoacoustic and photothermal deflection. We show that while the photothermal signal is significantly affected in the case of highly scattering media, it is independent of scattering for optically thin samples. Numerical estimates of the scattering contribution and comparison with experimental results are given. We also elucidate the relationship between photothermal and diffuse reflectance spectroscopies.

Loss mechanisms in resonant spectrophones.

Quality factors and resonant frequencies of a resonant spectrophone have been measured as a function of pressure and the results compared to theoretical predictions which took into account classical surface and volumetric losses and molecular relaxation. Buffer gases investigated included the five noble gases, H(2), N(2), O(2), CO(2), N(2)O, and SF(6). Typically 95% of the cavity losses were accounted for theoretically. Frequency shifts due to relaxational dispersion, nonideal gas behavior, and classical boundary layer effects were observed; all behaved as predicted by theory.

Reciprocal passive mode locking of a rhodamine 6G dye laser and the Ar(+) pump laser.

A rhodamine 6G dye laser, internally pumped within the extended cavity of an Ar(+)-ion laser, is mode locked when its cavity length is matched to half that of the pump laser: the 5145-A argon laser line is passively mode locked by the combination of the saturable absorption and the lasing action of the dye, which is in turn synchronously pumped and mode locked. Tunable (5650-5950-A) ~10 psec pulses are generated, and the average output power is ~80 mW.

Photothermal deflection spectroscopy and detection.

The theory for a sensitive spectroscopy based on the photothermal deflection of a laser beam is developed. We consider cw and pulsed cases of both transverse and collinear photothermal deflection spectroscopy for solids, liquids, gases, and thin films. The predictions of the theory are experimentally verified, its implications for imaging and microscopy are given, and the sources of noise are analyzed. The sensitivity and versatility of photothermal deflection spectroscopy are compared with thermal lensing and photoacoustic spectroscopy.

Novel CO(2)/N(2)O waveguide laser.

We present a new design for a waveguide laser which is easily constructed from readily available materials. We have demonstrated its operation for CO(2) (8.5-W output) and N(2)O (1.5-W output).

Electron microscopy of living insects.

Electron micrographs of living specimens of the various developmental stages of the insect Tribolium confusum have been obtained with a scanning electron microscope. In most cases the specimens resumed their normal activity after being examined with the electron microscope and under went metamorphosis into the next stage.