Background: Thalidomide is an anti-inflammatory and immunomodulatory agent with proven efficacy in several refractory inflammatory skin conditions including photoexacerbated skin diseases. The effects of thalidomide o...Background: Thalidomide is an anti-inflammatory and immunomodulatory agent with proven efficacy in several refractory inflammatory skin conditions including photoexacerbated skin diseases. The effects of thalidomide on ultraviolet (UV)-induced cutaneous damage in humans have not been extensively studied. We describe the results of minimal erythema dose (MED) testing in nonlesional skin of three patientswith chronic cutaneous lupus erythematosus (CCLE) before and after treatment with thalidomide. Objectives: To determine whether thalidomide treatment provides clinical and histological evidence of photoprotection from acute UV injury. Methods: MED testing was performed in nonlesional skin of three patients with CCLE before and after treatment with thalidomide. Skin biopsy specimens were taken from MED sites for in situ immunochemistry. Results: In each patient, the MED to UVB irradiation was significantly higher while the patient was receiving thalidomide treatment than in the absence of thalidomide, suggesting a systemic photoprotective effect. Thalidomide treatment had no significant effect on markers of apoptosis including sunburn cell formation and terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end labelling, which identifies single-strand breaks in DNA. Conclusions: Thalidomide inhibits acute UVB erythema at 24h after exposure, as a 100-mg daily dose of this drug for 4 weeks conveyed a sun protection factor of 1.56 to > 4.0. We conclude that inhibition of UVB-induced inflammation may, in part, explain the therapeutic benefits of this agent on photosensitive diseases.展开更多
Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular in...Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.展开更多
The protective role of xanthophyll cycle in resurrection angiosperm Boea hygrometrica (Bunge) R.Br. was investigated by analysis of the changes of chlorophyll fluorescence and xanthophyll cycle components in response ...The protective role of xanthophyll cycle in resurrection angiosperm Boea hygrometrica (Bunge) R.Br. was investigated by analysis of the changes of chlorophyll fluorescence and xanthophyll cycle components in response to dehydration and rehydration in detached leaves under very weak light condition (3 mumol photons.m(-2).s(-1)) and in the dark. With declines in the values of PSII photochemical efficiency (Fv/Fm), PSII actual quantum yield (Phi(PSII)), photochemical quenching (qP) and non-photochemical quenching (NPQ) during dehydration, zeaxanthin significantly increased in control Boea leaves under very weak light condition, while no zeaxanthin accumulation was detected in Boea leaves treated with dithiothreitol (DTT) and Boea leaves in the dark, and after 3 d rehydration, the parameters Fv/Fm, Phi(PSII), qP and NPQ showed full recovery in control Boea leaves under very weak light condition, but the parameters only underwent partial recovery in Boea leaves treated with DTT and Boea leaves in the dark, suggesting that the recovery of photosystem II (PSII) photochemical activities in Boea leaves was obviously affected by treatments with DTT and darkness, therefore, zeaxanthin may play an important protective role in desiccated Boea leaves even under very weak light conditions.展开更多
Silicon-based electrodes have attracted great attention in the artificial photosynthetic systems that mimic natural photosynthesis and directly convert the solar energy into chemical energy. Despite significant effort...Silicon-based electrodes have attracted great attention in the artificial photosynthetic systems that mimic natural photosynthesis and directly convert the solar energy into chemical energy. Despite significant efforts to date,catalytic stability of the silicon photoelectrodes is limited by their poor electrochemical stability. The formation of passivation or protective layers provides a feasible strategy to improve the photocatalytic stability of silicon photoelectrodes. Many candidates including metals, metal oxides, metal silicides and polymers have been explored as the protection layers for silicon photoelectrodes. The present review gives a concise overview of the protected silicon photoanodes for water oxidation with a focus on the relationship between the structural architecture of silicon photoanodes and their photocatalytic activity and stability.展开更多
Mesenchymal stem ceils （MSCs） have been demonstrated to have promising therapeutic benefits for a variety of neurological dis- eases; however, the underlying mechanisms are poorly understood. Here, we showed that in...Mesenchymal stem ceils （MSCs） have been demonstrated to have promising therapeutic benefits for a variety of neurological dis- eases; however, the underlying mechanisms are poorly understood. Here, we showed that intravitreal infusion of MSCs promoted retinal ganglion cell （RGC） survival in a mouse model of acute glaucoma, with significant inhibition of microglial activation, production of TNF-α, IL-1β, and reactive oxygen species, as well as caspase-8 and caspase-3 activation. In vitro, MSCs inhibited both caspase-8-mediated RGC apoptosis and microgUal activation, partly via the action of stanniocalcin 1 （STCl）. Furthermore, we found that microRNA-21a-Sp （miR-21） and its target, PDCD4, were essential for STC1 production and the neuroprotective property of MSCs in vitro and in vivo. Importantly, miR-21 overexpression or PDCD4 knockdown augmented MSC-mediated neuroprotective effects on acute glaucoma. These data highlight a previously unrecognized neuroprotective mechanism by which the miR-21/ PDCD4 axis induces MSCs to secrete STC1 and other factors that exert neuroprotective effects. Therefore, modulating the miR- 21/PDCD4 axis might be a promising strategy for clinical treatment of acute glaucoma and other neurological diseases.展开更多
文摘Background: Thalidomide is an anti-inflammatory and immunomodulatory agent with proven efficacy in several refractory inflammatory skin conditions including photoexacerbated skin diseases. The effects of thalidomide on ultraviolet (UV)-induced cutaneous damage in humans have not been extensively studied. We describe the results of minimal erythema dose (MED) testing in nonlesional skin of three patientswith chronic cutaneous lupus erythematosus (CCLE) before and after treatment with thalidomide. Objectives: To determine whether thalidomide treatment provides clinical and histological evidence of photoprotection from acute UV injury. Methods: MED testing was performed in nonlesional skin of three patients with CCLE before and after treatment with thalidomide. Skin biopsy specimens were taken from MED sites for in situ immunochemistry. Results: In each patient, the MED to UVB irradiation was significantly higher while the patient was receiving thalidomide treatment than in the absence of thalidomide, suggesting a systemic photoprotective effect. Thalidomide treatment had no significant effect on markers of apoptosis including sunburn cell formation and terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end labelling, which identifies single-strand breaks in DNA. Conclusions: Thalidomide inhibits acute UVB erythema at 24h after exposure, as a 100-mg daily dose of this drug for 4 weeks conveyed a sun protection factor of 1.56 to > 4.0. We conclude that inhibition of UVB-induced inflammation may, in part, explain the therapeutic benefits of this agent on photosensitive diseases.
文摘Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.
文摘The protective role of xanthophyll cycle in resurrection angiosperm Boea hygrometrica (Bunge) R.Br. was investigated by analysis of the changes of chlorophyll fluorescence and xanthophyll cycle components in response to dehydration and rehydration in detached leaves under very weak light condition (3 mumol photons.m(-2).s(-1)) and in the dark. With declines in the values of PSII photochemical efficiency (Fv/Fm), PSII actual quantum yield (Phi(PSII)), photochemical quenching (qP) and non-photochemical quenching (NPQ) during dehydration, zeaxanthin significantly increased in control Boea leaves under very weak light condition, while no zeaxanthin accumulation was detected in Boea leaves treated with dithiothreitol (DTT) and Boea leaves in the dark, and after 3 d rehydration, the parameters Fv/Fm, Phi(PSII), qP and NPQ showed full recovery in control Boea leaves under very weak light condition, but the parameters only underwent partial recovery in Boea leaves treated with DTT and Boea leaves in the dark, suggesting that the recovery of photosystem II (PSII) photochemical activities in Boea leaves was obviously affected by treatments with DTT and darkness, therefore, zeaxanthin may play an important protective role in desiccated Boea leaves even under very weak light conditions.
基金supported by the National Natural Science Foundation of China(21201138)the National Basic Research Program of China(2012CB619401)
文摘Silicon-based electrodes have attracted great attention in the artificial photosynthetic systems that mimic natural photosynthesis and directly convert the solar energy into chemical energy. Despite significant efforts to date,catalytic stability of the silicon photoelectrodes is limited by their poor electrochemical stability. The formation of passivation or protective layers provides a feasible strategy to improve the photocatalytic stability of silicon photoelectrodes. Many candidates including metals, metal oxides, metal silicides and polymers have been explored as the protection layers for silicon photoelectrodes. The present review gives a concise overview of the protected silicon photoanodes for water oxidation with a focus on the relationship between the structural architecture of silicon photoanodes and their photocatalytic activity and stability.
基金This study was partially supported by the Natural Science Foundation of China （81470627 and 81670897）, key projects from the Natural Science Foundation of Guangdong Province （201_4A030308005）, and Guangdong Natural Science Funds for Distinguished Young Scholar （2016A030306006）.
文摘Mesenchymal stem ceils （MSCs） have been demonstrated to have promising therapeutic benefits for a variety of neurological dis- eases; however, the underlying mechanisms are poorly understood. Here, we showed that intravitreal infusion of MSCs promoted retinal ganglion cell （RGC） survival in a mouse model of acute glaucoma, with significant inhibition of microglial activation, production of TNF-α, IL-1β, and reactive oxygen species, as well as caspase-8 and caspase-3 activation. In vitro, MSCs inhibited both caspase-8-mediated RGC apoptosis and microgUal activation, partly via the action of stanniocalcin 1 （STCl）. Furthermore, we found that microRNA-21a-Sp （miR-21） and its target, PDCD4, were essential for STC1 production and the neuroprotective property of MSCs in vitro and in vivo. Importantly, miR-21 overexpression or PDCD4 knockdown augmented MSC-mediated neuroprotective effects on acute glaucoma. These data highlight a previously unrecognized neuroprotective mechanism by which the miR-21/ PDCD4 axis induces MSCs to secrete STC1 and other factors that exert neuroprotective effects. Therefore, modulating the miR- 21/PDCD4 axis might be a promising strategy for clinical treatment of acute glaucoma and other neurological diseases.
