LED-pumped eye-safe pulse laser with an extracavity optical parametric oscillator.

An LED-side-pumped Nd:YAG/Cr4+:YAG passively Q-switched (PQS) laser containing an extracavity optical parametric oscillator (EOPO) is demonstrated. As far as we know, it is the first LED-pumped eye-safe laser. The Nd:YAG pump module is optimized to increase the PQS pulse energy to 24 mJ at 1064 nm. By using a single-pass EOPO design, the output energy of the signal pulse at 1573 nm is 7.44 mJ with a pulse width of 16 ns, the peak power is 434 kW, and the pump-to-signal conversion efficiency is 31%. For double-pass EOPO operation, the pump-to-signal conversion efficiency increases to 45.8%, the output energy of signal pulse is up to 10.98 mJ with a pulse width of 23.5 ns, and the peak power is 459 kW.

Effects of Maturity at Harvest and Fermentation Conditions on Bioactive Compounds of Cocoa Beans.

Cocoa beans and cocoa products contain considerable amounts of bioactive compounds. Harvesting cocoa fruit too early or too late may have effects on the phenolic and alkaloid concentrations of the cocoa powder. Fermentation, a primary processing used to transform cocoa beans to cocoa powder, may also influence the contents of bioactive compounds. In this study, proanthocyanidins, the major compounds in cocoa polyphenols, caffeine and theobromine of cocoa beans, were evaluated at different maturities at harvest, and with different fermentation durations, with and without the addition of a commercial enzyme, Pectinex® Ultra SP-L. The amounts of proanthocyanidins, caffeine and theobromine, and the antioxidant capacities of the unfermented cocoa beans increased as the fruits matured. The values ranged from 16.12-27.28 g catechin equivalents (CE)/100 g dry weight (DW); 99.66-173.61 mg/100 g DW; 556.39-948.84 mg/100 g DW; 23.23-26.32 mol Trolox equivalents (TE)/100 g DW, respectively. Prolonged fermentation with or without the addition of pectinase, from three to seven days, significantly reduced the amounts of these compounds present. Fermentation using the enzyme significantly reduced the proanthocyanidin content and antioxidant capacity of the cocoa powder, with the overall means decreasing from 8.93-4.93 g CE/100 g DW and from 15.81-12.95 g mol TE/100 g DW, respectively. Two-way ANOVA analyses showed that the proanthocyanidins, caffeine, theobromine contents and the antioxidant capacity of cocoa beans were strongly dependet to their stages of maturity, fermentation methods and fermentation duration.

Descending pressor pathways from the dorsomedial and ventrolateral medulla of cats.

Descending pathways of the pressor areas in dorsomedial (DM) and ventrolateral (VLM) medulla were studied physiologically and anatomically. The electrically induced pressor response from either DM or VLM that previously responded to glutamate (Glu) was slightly but not significantly decreased after splitting the medulla at midline. After electrolytic lesion in the ipsilateral lateral tegmental field (LTF) of caudal medulla, 4 mm caudal to the obex, electrically induced pressor responses from DM and VLM previously responded to Glu decreased significantly from 71% to 20% and from 57% to 7%, respectively. The dorsomedial LTF was found to be responsible for the DM responses, while the ventrolateral LTF for the VLM responses. Following electrolytic lesion in the ipsilateral dorsolateral funiculus (DLF) between C4 and C5, the magnitude of DM-induced pressor responses decreased significantly from 74% to 37% and that of the VLM from 75% to 14%. After electrolytic lesion at the ipsilateral intermediolateral cell column (IML) of T2 spinal cord, the pressor responses on DM and VLM stimulations also decreased significantly. Lesioning the remaining IML almost completely abolished the induced pressor responses. Seven to ten days following kainic acid injections into DM or VLM to destroy neurons therein, degenerative fibers (silver impregnation) were found to descend from the medulla to thoracic spinal cord, principally ipsilaterally, but with some fibers crossing to the controlateral medulla. Data from both physiological and anatomical studies suggest that fibers from DM and VLM descend ipsilaterally through different pathways and converge at LTF 4 min caudal to the obex, and then further descend to DLF before reaching the thoracic IML.

Using ultrasonic measurement of cardiac size in predicting congenital heart defect.

A Duplex Color apparatus equipped with real-time imaging and Doppler sector scanner was used to scan fetal hearts, ranging from 17 to 41 weeks gestational age. A total of 323 normal fetuses were studied. The four-chamber view was obtained in a horizontal section just above the level of the fetal diaphragm. Five variables of the Chinese fetal heart in relation to the width of the right ventricle, width of the left ventricle, ratio of right ventricle/left ventricle (RV/LV), length of the fetal heart and the cardiac volume of a four-chamber view were set against gestational age in weeks and expressed in regression equations. The ratio of RV/LV is quite constant in relation to the gestational age. The mean ranges between 0.9916 for 17 weeks gestation and 1.0045 for a term fetus. In 10 abnormal cases with congenital cardiac defects, using the 5th and the 95th percentiles of this normal data as cutoff points, the RV/LV ratio had the highest sensitivity rate of 70% (7/10) in predicting fetal cardiac anomaly. The width of the left ventricle was the second most sensitive parameter with a sensitivity of 4/10 (40%). The RV/LV ratio of a four-chamber view is a simple, time-saving screening parameter for predicting congenital cardiac defects antenatally.