Induced marine fungus Chondrostereum sp. as a means of producing new sesquiterpenoids chondrosterins I and J by using glycerol as the carbon source.

Chondrostereum sp., a marine fungus isolated from a soft coral Sarcophyton tortuosum, can yield hirsutane framework sesquiterpenoids. However, the metabolites profiles vary dramatically with the composition change of the culture media. This fungus was cultured in a liquid medium containing glycerol as the carbon source, and two new metabolites, chondrosterins I and J (1 and 2), were obtained. Their structures were elucidated primarily based on MS, NMR and X-ray single-crystal diffraction data. By comparison with the known hirsutane sesquiterpenoids, chondrosterins I and J have unique structural features, including a methyl was migrated from C-2 to C-6, and the methyl at C-3 was carboxylated. Compound 2 exhibited potent cytotoxic activities against the cancer cell lines CNE-1 and CNE-2 with the IC50 values of 1.32 and 0.56 µM.

[Effects of single mode's high-order aberrations on visual acuity corrected using adaptive optics technique].

OBJECTIVE: To analyze the effects of single mode's high-order aberration on visual acuity in real time dynamically corrected using adaptive optics technique. METHODS: Control study. In a dark room, twelve young healthy volunteers were administrated with 5 g/L phenylephrine to fully dilate the right eye's pupil to a diameter over 6 mm. The subjects' myopia and astigmatism were fully corrected using optical lenses. Coma, trefoil, spherical aberration and other forth-order aberrations except for spherical aberration were corrected using adaptive optics, and 100% contrast visual acuity was simultaneously measured. RESULTS: All single mode's high-order aberrations were fully corrected, whereas other aberrations remained unchanged. Mean visual acuity of subjects was improved by 0.021 LogMAR, 0.017 LogMAR, 0.022 LogMAR and 0.025 LogMAR after correction of coma, trefoil, spherical aberration and other forth-order aberrations except for spherical aberration, respectively. Ratio of change in visual acuity was (-0.40 ± 1.22) LogMAR/µm, (-0.20 ± 0.61) LogMAR/µm, (-0.80 ± 1.44) LogMAR/µm and (-0.30 ± 0.57) LogMAR/µm, respectively. There was a linear correlation between visual acuity after correction of single mode's different high-order aberrations and RMS of residual aberrations (R(2) = 0.13, P < 0.01). CONCLUSION: Among high-order aberrations in normal human eye, spherical aberration generates a most impact on visual acuity, followed by coma, other forth-order aberrations except for spherical aberration and trefoil. A linear correlation was found between change in visual acuity and RMS of residual aberrations.

[Initial research of customized aberration correction with adaptive optics technique].

OBJECTIVE: To analyze the effects of different wavefront-guided aberration ablation patterns on visual function using adaptive optics technique and explore the effective and feasible pattern of customized refractive surgery. METHODS: Control study. Under dark condition, six volunteers'right eyes were fully dilated with 5 g/L phenyl ephedrine. The myopia and astigmatism were first fully corrected with optical lens, and then 100% contrast visual acuity of different wavefront correction patterns was detected using adaptive optics system in through a 6.0 mm pupil optical path. RESULTS: All of the eight different aberration correction strategies obtained excellent correction effect. On the basis of this correction, visual acuity test was performed. The results showed that all aberration correction strategies improved the visual acuity compared with static correction. Correction of high order aberrations and full correction of aberrations could obtain better visual acuity than that of only correction of low order aberrations. Correction of aberrations from second to third order and fourth order spherical aberration second only to full correction of aberration. CONCLUSION: As for low myopia patients, eliminating ocular high order aberrations could improve visual acuity. Correction of aberration from second to third order and fourth spherical aberration might be an effective and feasible pattern of customized refractive surgery.

Small-phase retrieval with a single far-field image.

A method to retrieve small phase aberration from a single far-field image is proposed. It is found that in small phase condition, the odd and even parts of phase aberration can be obtained with a simple linear calculation method. The difference between a single measured image with aberration and the calibrated image with inherent aberration are used in the calculation process. It is proved that the most part of the inherent phase aberration of the imaging system must be of even type, such as defocus, astigmatism, etc., to keep the method working. Results of numerical simulations on atmosphere disturbed phase aberrations show that the proposed small phase retrieval method works well when the RMS phase error is less than 1 rad. It is also shown that the method is valid in noise condition when SNR>100.