Identification of genes revealed differential expression profiles and lignin accumulation during leaf and stem development in tea plant (Camellia sinensis (L.) O. Kuntze)

Lignin is a complex aromatic heteropolymer that plays essential roles in mechanical support, water transport, and response to biotic and abiotic stresses. The tea plant is a leaf-type beverage crop, which serves as a resource for non-alcoholic beverage tea. The content and distribution of lignin in tea plant leaves seriously affect the quality of tea. However, the biosynthetic pathways of lignin remain to be characterized in the tea plant. In the present study, lignin accumulation was investigated in tea plant leaves and stems at three developmental stages. The lignin content continuously increased during leaf and stem development in both tea plant cultivars 'Fudingdabai' and 'Suchazao.' The lignin distribution and anatomical characteristics of the tea plant leaves coincided with lignin accumulation and showed that lignin is mainly distributed in the epidermis, xylem, and vascular bundle sheath. 'Suchazao' exhibits a low lignin content and lacks a vascular bundle sheath. Twelve genes encoding the enzymes involved in the lignin biosynthesis of tea plant were identified and included CsPAL, CsC4H, Cs4CL, CsHCT, CsC3H, CsCCoAOMT, CsCCR, CsCAD, CsF5H, CsCOMT, CsPER, and CsLAC. The expression profiling of lignin biosynthesis-related genes and analysis of lignin accumulation may help elaborate the regulatory mechanisms of lignin biosynthesis in tea plant.

Correction to: Two MYB transcription factors (CsMYB2 and CsMYB26) are involved in flavonoid biosynthesis in tea plant [Camellia sinensis (L.) O. Kuntze]

Following publication of the original article [1], the author reported that there was a mismatch between figures and their legends.

Officinalins A and B, a pair of C23 terpenoid epimers with a tetracyclic 6/7/5/5 system from Salvia officinalis

Officinalins A (1) and B (2), a pair of 6/7/5/5 tetracyclic C₂₃ terpenoid epimers with a unique tetracycline-[9.6.0.0^3,8.0^12,16]-heptadecane core and a peroxide bridge, were isolated from the leaves of Salvia officinalis.

Taiwanoids A-D, four dimeric diterpenoids featuring tetracyclic [7. 75, 9. 4. 05, 10. 08, 9] octodecane from Taiwania cryptomerioidesim

Biogenesis-inspired chemical research of the leaves of Taiwania cryptomerioides afforded four unprecedented dimeric diterpenes, featuring a tetracyclic [7. 75, 9. 4. 05, 10. 08, 9] octodecane core: taiwanoids A-D (1-4). The structures of these compounds were determined on the basis of comprehensive spectral analysis, chemical conversions and X-ray crystallography. A possible biosynthetic pathway for compounds 1-4 was proposed. Compounds 2 and 3 exerted a 5.37 and 6.26-fold potentiation effect on bortezmib (BTZ) susceptibility at a tested concentration of 20 μM, respectively.

Two MYB transcription factors (CsMYB2 and CsMYB26) are involved in flavonoid biosynthesis in tea plant [Camellia sinensis (L.) O. Kuntze]

BACKGROUND

Flavonoids are secondary metabolites that play important roles in the entire tea plant life cycle and have potential health-promoting properties. MYB transcription factors (TFs) are considered potentially important regulators of flavonoid biosynthesis in plants. However, the molecular mechanisms by which MYB TFs regulate the flavonoid pathway in tea plant remain unknown.

RESULTS

In this study, two R2R3-MYB TFs (CsMYB2 and CsMYB26) involved in flavonoid biosynthesis in tea plant were investigated. The genes encoding CsMYB2 and CsMYB26 were cloned from the tea plant cultivar 'Longjing 43'. Phylogenetic analysis showed that CsMYB2 and CsMYB26 were grouped into the proanthocyanidin biosynthesis-related MYB clade. Multiple sequence alignment revealed that conserved motif 1 in the two MYB factors was related to the bHLH TF. Subcellular localization assays suggested that CsMYB2 localized in the nucleus. Promoter analysis indicated that CsMYB2, CsMYB26 and the related structural genes contain MYB recognition elements. The expression levels of the CsMYB2 and CsMYB26 genes and the structural genes in the flavonoid biosynthesis pathway were determined in leaves from various sites in the two tea plant cultivars 'Longjing 43' and 'Baiye 1 hao'.

CONCLUSIONS

The expression levels of these genes were correlated with the accumulated flavonoid content. The results demonstrated that the expression level of CsF3'H may be regulated by CsMYB2 and that CsMYB26 expression is positively correlated with CsLAR expression. The relative transcriptional level of CsMYB26 may be the main reason for the different epigallocatechin contents between the tea plant cultivars 'Longjing 43' and 'Baiye 1 hao'. Our results will serve as a reference for the potential regulatory roles of CsMYB2 and CsMYB26 in flavonoid biosynthesis in tea plant and may also assist biologists in improving tea quality.

Two MYB transcription factors (CsMYB2 and CsMYB26) are involved in flavonoid biosynthesis in tea plant [Camellia sinensis (L.) O. Kuntze]

BACKGROUND

Flavonoids are secondary metabolites that play important roles in the entire tea plant life cycle and have potential health-promoting properties. MYB transcription factors (TFs) are considered potentially important regulators of flavonoid biosynthesis in plants. However, the molecular mechanisms by which MYB TFs regulate the flavonoid pathway in tea plant remain unknown.

RESULTS

In this study, two R2R3-MYB TFs (CsMYB2 and CsMYB26) involved in flavonoid biosynthesis in tea plant were investigated. The genes encoding CsMYB2 and CsMYB26 were cloned from the tea plant cultivar 'Longjing 43'. Phylogenetic analysis showed that CsMYB2 and CsMYB26 were grouped into the proanthocyanidin biosynthesis-related MYB clade. Multiple sequence alignment revealed that conserved motif 1 in the two MYB factors was related to the bHLH TF. Subcellular localization assays suggested that CsMYB2 localized in the nucleus. Promoter analysis indicated that CsMYB2, CsMYB26 and the related structural genes contain MYB recognition elements. The expression levels of the CsMYB2 and CsMYB26 genes and the structural genes in the flavonoid biosynthesis pathway were determined in leaves from various sites in the two tea plant cultivars 'Longjing 43' and 'Baiye 1 hao'.

CONCLUSIONS

The expression levels of these genes were correlated with the accumulated flavonoid content. The results demonstrated that the expression level of CsF3'H may be regulated by CsMYB2 and that CsMYB26 expression is positively correlated with CsLAR expression. The relative transcriptional level of CsMYB26 may be the main reason for the different epigallocatechin contents between the tea plant cultivars 'Longjing 43' and 'Baiye 1 hao'. Our results will serve as a reference for the potential regulatory roles of CsMYB2 and CsMYB26 in flavonoid biosynthesis in tea plant and may also assist biologists in improving tea quality.

[Effectiveness evaluation between enhanced recovery after surgery and traditional treatment in unilateral total knee arthroplasty]

Objective: To investigate the clinical effect of enhanced recovery after surgery (ERAS) in unilateral total knee arthroplasty (TKA). Methods: Retrospective analysis of 98 patients received unilateral TKA from September 2015 to September 2016 in the Orthopaedic Departmentof Affiliated Hospital of Logistics University of Chinese People's Armed Police Forces.Of the patients, 52 cases were treated by traditional operation (routine group) and the other 46 cases were treated with ERAS concept (ERAS group). The following data were gathered and statistically analyzed between the groups: gender, age, body mass index, preoperative hemoglobin, preoperative visual analogue scale (VAS) score, postoperative visible blood loss, postoperative hemoglobin at 24 hour after operation, blood transfusion rate, postoperative VAS score, length of hospital stay, the satisfaction rate, preoperative and 1 and 6 months postoperative evaluation with hospital for special surgery knee score (HSS), postoperative range of motion (ROM) of knees after 2 weeks, 1 month and 6 months of surgery, incidence rate of complications after surgery.Data between groups were analyzed with one-factor analysis of variance or chi-square test. Results: There was no significant difference in preoperative data between two groups.Postoperative visible blood loss of ERAS group was significantly lower than that in routine group[(224±59) vs (361±70) ml, t=4.723, P<0.01]; postoperative hemoglobin after 24 hours in ERAS group was significantly higher than that in routine group[(109±8) vs (96±10) g/L, t=-3.297, P=0.004]; blood transfusion rate of ERAS group was significantly lower than that in routine group[6.5 %(3/46) vs 46.2%(24/52), χ(2)=19.207, P<0.01]; the 12-hour and 48-hour postoperative VAS scores in ERAS groups were both significantly lower than those in routine group (t=3.708, 3.894, both P<0.05); length of hospital stay in ERAS group was significantly shorter than that in routine group[(6.8±1.2) vs (13.1±2.6) d, t=6.924, P<0.01]; HSS scores of ERAS groups at 1 month and 6 months after surgery were both significantly higher than those in routine group (t=-3.677, -3.594, both P<0.05); knees ROM in ERAS group at 2 weeks and 1 month after surgery were both significantly higher than those in routine group (t=-4.628, -4.442, both P<0.05); the rate of postoperative nausea vomiting in ERAS group was significantly lower than that in routine group[13.0%(6/46) vs 48.1%(25/52), χ(2)=13.852, P=0.002]. VAS score at 1 month after surgery, knees ROM at 6 months after surgery and the satisfaction rate were all comparable between the two groups (t=0.412, -1.026, χ(2)=3.695, all P>0.05). Conclusions: Condition of patients treated by unilateral TKA under ERAS model improves effectively during perioperative period when compared with routine treatment, patients have earlier rehabilitation and better experience in hospital and operation.

[Analyses of pathogenic factors and clinicopathological characteristics of vocal leukoplakia]

Objective: To investigate the pathogenic factors of vocal leukoplakia and its clinical and pathological features. Methods: Eighty-one patients with vocal cord leukoplakia who underwent surgery between February 2010 and December 2016 and 160 volunteers without pharyngeal symptoms designed as controls were included in this case control study. The clinicopathological characteristics of 81 patients were summarized and analyzed synthetically. Results: There was statistical significance in reflux symptom index(RSI), reflux finding score(RFS), smoking index, and drinking index between case group and control group(Z=-5.35, -4.82, -4.76, -2.44, P<0.05). The voice-using duration per day in case group was significantly longer than that of control group.There was no statistical significance in hospital anxiety and depression scale for anxiety(HADA) scores、hospital anxiety and depression scale for depression(HADD) scores between case group and control group(P>0.05). In 42 patients who received 24-hour dual probe pH monitoring the prevalence of pathologic LPR was 42.8%. In 81 patients, 39(48%)patients were pathologically diagnosed as squamous cell hyperplasia, 18(22%)patients as mild dysplasia, 12(15%)sides as moderate dysplasia , 10(12%)patients as severe dysplasia and 2(2%)patients as carcinoma in-situ. The average age of high-risk pathological vocal leukoplakia was significantly higher than that of low-risk leukoplakia(t=-2.73, P<0.01). The propotion of speckled leukoplakia in high-risk leukoplakia was significantly higher than that of low-risk leukoplakia(χ(2)=23.81, P<0.01). There was no statistical significance between high-risk leukoplakia and low-risk leukoplakia in the prevalence of pathologic LPR(P>0.05). The bilateral lesions, speckled leukoplakia were more likely to relapse(χ(2)=4.27, 12.17, P<0.05). The more serious the pathology, the more likely it was to relapse (Z=-2.168, P=0.03). There was no statistical significance between recurrence group and non-recurrence group in the prevalence of pathologic LPR(P>0.05). Conclusions: LPR, smoke constitute the risk factors of vocal cord leukoplakia. Drinking, voice abuse are related to vocal cord leukoplakia. Senile, speckled leukoplakia are more likely to be malignancy. A speckled leukoplakia, bilateral leukoplakia, severe pathological degree are important factors to predict recurrence.

Low-protein diet improves meat quality of growing and finishing pigs through changing lipid metabolism, fiber characteristics, and free amino acid profile of the muscle

The objective of the study was to investigate the effect of feeding reduced CP, AA-supplemented diets on meat quality in growing and finishing pigs as well as the related mechanism. In experiment 1, 18 growing pigs (36.5 kg BW) were assigned randomly and fed 1 of 3 corn-soybean meal diets containing either 18% CP (normal protein, NP), 15% CP (low protein, LP), or 12% CP (very low protein, VLP). In experiment 2, 18 finishing pigs (62.3 kg BW) were allotted randomly into 1 of the following diets: 16% CP (NP), 13% CP (LP), or 10% CP (VLP). In both experiments, the LP and VLP diets were supplemented with crystalline AA to achieve equal content of standardized ileal digestible lysine, methionine, threonine, and tryptophan. At the end of each experiment, all pigs were slaughtered to collect longissimus dorsi muscle (LM) samples. Samples were used for determining meat quality, intramuscular fat (IMF) content, fatty acid composition, free AA profile, and expression of genes for myosin heavy chain isoforms. Results showed that growing and finishing pigs fed the LP diets increased (P < 0.05) redness value of LM, while finishing pigs fed the LP and VLP diets decreased (P < 0.05) the shear force values. Compared with the NP diet, growing and finishing pigs fed lower CP diets had higher (P < 0.05) contents of IMF and MUFA, and lower (P < 0.05) contents of PUFA. Besides, higher (P < 0.05) expression levels of type I and/or IIa muscle fibers were observed in LP diet-fed growing and finishing pigs, and greater concentrations of taurine and tasty AA in VLP diet-fed growing and finishing pigs. Taken together, our results indicate that low-protein diets could positively affect meat quality of growing and finishing pigs, and likely through regulation of IMF content and fatty acid composition, fiber characteristics, and free AA profile in the muscle.

Genome-wide identification and expression analysis of GRAS family transcription factors in tea plant (Camellia sinensis)

GRAS proteins are important transcription factors that play multifarious roles in regulating the growth and development as well as stress responses of plants. Tea plant is an economically important leaf -type beverage crop. Information concerning GRAS family transcription factors in tea plant is insufficient. In this study, 52 CsGRAS genes encoding GRAS proteins were identified from tea plant genome database. Phylogenetic analysis of the identified GRAS proteins from tea plant, Arabidopsis, and rice divided these proteins into at least 13 subgroups. Conserved motif analysis revealed that the gene structure and motif compositions of the proteins were considerably conserved among the same subgroup. Functional divergence analysis indicated that the shifted evolutionary rate might act as a major evolutionary force driving subfamily-specific functional diversification. Transcriptome analysis showed that the transcriptional levels of CsGRAS genes under non-stress conditions varied among different tea plant cultivars. qRT-PCR analysis revealed tissue and development stage-specific expression patterns of CsGRAS genes in tea plant. The expression patterns of CsGRAS genes in response to abiotic stresses and gibberellin treatment suggested the possible multiple functions of these genes. This study provides insights into the potential functions of GRAS genes.

[Impacts of EGFR 19 exon mutations on brain metastases in treatment-naïve patients with lung adenocarcinoma]

Objective: To investigate the relationship between the status of epidermal growth factor receptor (EGFR) mutations and brain metastases in patients with lung adenocarcinoma. Methods: From August 2010 to May 2015, a total of 1 063 lung adenocarcinoma patients with identified status of EGFR mutations in Shanxi Cancer Hospital were enrolled, of which 456 patients had EGFR mutations. Multivariate Logistic regression model was used to analyze the correlation between EGFR mutation status and brain metastases in patients with lung adenocarcinoma. Results: In 125 patients with brain metastases before initial treatment, 65 patients had EGFR mutations, including 36 patients with deletion mutations in exon 19. The frequency of EGFR 19 exon mutation was 28.8% (36/125). Among 456 patients with EGFR mutations, 65(14.3%) patients were with brain metastases, in which 36(55.0%) had deletion mutations in exon 19. The multivariate analysis showed that age, Eastern Cooperative Oncology Group (ECOG) score, EGFR mutations and N staging were associated with brain metastases(P<0.05). Further subgroup multivariate analyses showed that age, ECOG score, mutation status in exon 19 and N staging were associated with brain metastases (P<0.05). Conclusions: EGFR mutation status is related to brain metastases. Mutations in EGFR exon 19 is an independent risk factor for brain metastases.

CsGOGAT Is Important in Dynamic Changes of Theanine Content in Postharvest Tea Plant Leaves under Different Temperature and Shading Spreadings

We analyzed the changes of theanine content in postharvest tea leaves under high temperature (38 °C), low temperature (4 °C), and shading spreadings by using ultrahigh-performance liquid chromatography. The differentially expressed proteins (DEPs), CsFd-GOGAT and CsNADH-GOGAT, which are involved in theanine biosynthesis pathway, were identified from the corresponding proteome data. The protein-protein interactions of CsFd-GOGAT and CsNADH-GOGAT, CsTS1, or CsNiR were verified by yeast two-hybrid technology. The expression profiles of 17 genes in theanine metabolism, including CsFd-GOGAT and CsNADH-GOGAT, were analyzed by quantitative real-time polymerase chain reaction. The correlations between the dynamic changes of theanine content and expression profiles of related genes and DEPs were analyzed. This study preliminarily proved the importance of CsGOGAT in dynamic changes of theanine content in postharvest tea leaves during spreading.

Novel cycloneolignans from Vernicia fordii with inhibitory effects on over-activation of BV2 cells in vitro

Novel natural products 7R, 8R, 7′R, 9′S-verniciasin A (1a), 7S, 8S, 7′S, 9′R- verniciasin A (1b), 7R, 8R, 7′R, 9′S−7′-methoxylverniciasin A (2a) and 7S, 8S, 7′S, 9′R−7′-methoxylverniciasin A (2b) were characterized from the seed capsule of Vernicia fordii. And the unique 9-O-9′−7, 9′-cyclo-8, 1′-neolignan skeleton with a seven-membered ring, was identified by extensive spectroscopic analysis. Further the possible biosynthetic pathway was briefly discussed. Interestingly, 1a, 2a, 1b and 2b all exhibited significant stereoselective inhibitory effects on NO production in LPS-induced BV2 microglia cell. Then the primary mechanism of the bioactivities and stereoselectivity was explored by means of bioassay and molecular docking.

Dynamics of levitated objects in acoustic vortex fields

Acoustic levitation in gaseous media provides a tool to process solid and liquid materials without the presence of surfaces such as container walls and hence has been used widely in chemical analysis, high-temperature processing, drop dynamics and bioreactors. To date high-density objects can only be acoustically levitated in simple standing-wave fields. Here we demonstrate the ability of a small number of peripherally placed sources to generate acoustic vortex fields and stably levitate a wide range of liquid and solid objects. The forces exerted by these acoustic vortex fields on a levitated water droplet are observed to cause a controllable deformation of the droplet and/or oscillation along the vortex axis. Orbital angular momentum transfer is also shown to rotate a levitated object rapidly and the rate of rotation can be controlled by the source amplitude. We expect this research can increase the diversity of acoustic levitation and expand the application of acoustic vortices.

Experimental investigations and phase-field simulations of triple-phase-separation kinetics within liquid ternary Co-Cu-Pb immiscible alloys

The phase-separation kinetics and microstructure evolution mechanisms of liquid ternary Co_{43}Cu_{40}Pb_{17} immiscible alloys are investigated by both the drop tube technique and phase-field method. Two successive phase separations take place during droplet falling and lead to the formation of a three-phase three-layer core-shell structure composed of a Co-rich core, a Cu-rich middle layer, and a Pb-rich shell. The Pb-rich shell becomes more and more conspicuous as droplet diameter decreases. Meanwhile, the Co-rich core center gradually moves away from the core-shell center. Theoretical analyses show that a larger temperature gradient inside a smaller alloy droplet induces the accelerated growth of the surface segregation shell during triple-phase separation. The residual Stokes motion and the asymmetric Marangoni convection result in the appearance of an eccentric Co-rich core and the core deviation degree is closely related to the droplet size and initial velocity. A three-dimensional phase-field model of ternary immiscible alloys, which considers the successive phase separations under the combined effects of Marangoni convection and surface segregation, is proposed to explore the formation mechanisms of three-phase core-shell structures. The simulated core-shell morphologies are consistent with the experimental observations, which verifies the model's validity in reproducing the core-shell dynamic evolution. Numerical results reveal that the development of three-phase three-layer core-shell structures can be attributed to the primary and then secondary phase separations dominated simultaneously by Marangoni convection and surface segregation. Furthermore, the effects of droplet temperature gradient on the growth kinetics of the surface segregation shell are analyzed in the light of phase-field theory.

Clinical efficacy of high retention enema with Chaishao Chengqi decoction modified with salvia miltiorrhiza in prevention of pancreatitis and hyperamylasemia after endoscopic retrograde cholangiopancreatography

AIM

To investigate the efficacy of high retention enema with Chaishao Chengqi decoction modified with salvia miltiorrhiza in the prevention of pancreatitis and hyperamylasemia after endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

Eighty-three patients who would undergo ERCP were randomly divided into a treatment group and a control group. Both groups were treated by fasting, rehydration, acid suppression, inhibition of pancreatic enzyme activity, use of antibiotics and other routine treatments. The treatment group was additionally treated with high retention enema by Chaishao Chengqi decoction modified with salvia miltiorrhiza 6 h before ERCP and 1 h after ERCP, twice a day. Before and after treatment, amylase (AMS) and high-sensitivity C-reactive protein (Hs-CRP) were detected. Meanwhile, cannulation time, operative time, postoperative abdominal pain, hospital stays, and hospitalization cost were compared.

RESULTS

One patient in the treatment group and two patients in the control group developed post-ERCP pancreatitis (PEP), and there was no significant difference in the rate of PEP between the two groups (P > 0.05). AMS at 3 h, AMS and Hs-CRP at 12 h and 24 h, the rate and degree of abdominal pain, the rate of post-ERCP hyperamylasemia (PEH), hospital stays, and hospitalization cost were all significantly better in the observation group than in the control group (P < 0.05). There was no significant difference between the two groups in cannulation time, operative time or Hs-CRP at 3 h.

CONCLUSION

High retention enema with Chaishao Chengqi decoction modified with salvia miltiorrhiza can effectively reduce the incidence of PEH, lower AMS and Hs-CRP, reduce the incidence of abdominal pain, shorten the length of hospital stay and reduce hospitalization costs, although it has no obvious effect on ERCP operative time and the incidence of PEP.

Transcriptomic analysis of the biosynthesis, recycling, and distribution of ascorbic acid during leaf development in tea plant (Camellia sinensis (L.) O. Kuntze)

Ascorbic acid (AsA), known as vitamin C, is an essential nutrient for humans and mainly absorbed from food. Tea plant (Camellia sinensis (L.) O. Kuntze) leaves can be a dietary source of AsA for humans. However, experimental evidence on the biosynthesis, recycling pathway and distribution of AsA during leaf development in tea plants is unclear. To gain insight into the mechanism and distribution of AsA in the tea plant leaf, we identified 18 related genes involved in AsA biosynthesis and recycling pathway based on the transcriptome database of tea plants. Tea plant leaves were used as samples at different developmental stages. AsA contens in tea plant leaves at three developmental stages were measured by reversed-phase high-performance liquid chromatography (RP-HPLC). The correlations between expression levels of these genes and AsA contents during the development of tea plant leaves were discussed. Results indicated that the l-galactose pathway might be the primary pathway of AsA biosynthesis in tea plant leaves. CsMDHAR and CsGGP might play a regulatory role in AsA accumulation in the leaves of three cultivars of tea plants. These findings may provide a further glimpse to improve the AsA accumulation in tea plants and the commercial quality of tea.

Liquid Supercoolability and Synthesis Kinetics of Quinary Refractory High-entropy Alloy

The high-entropy configuration of equiatomic multicomponent alloys opens an effective access to the development of advanced materials. Here we report the synthesis of a new quinary refractory WMoTaNbZr high-entropy alloy under electrostatic levitation condition. It showed a high liquidus temperature of 2686 K and achieved a maximum supercooling of 640 K (0.24 T_L) at molten state. The containerless measurements revealed a linear increasing tendency for both its liquid state density and the specific heat to emissivity ratio versus alloy supercooling. A high-entropy body-centered cubic (HEB) phase dominated its phase constitution despite the formation of a negligible amount of solid solution (Zr) phase. The dendritic growth of HEB phase always governed the crystallization process, attained a fastest growth velocity of 13.5 m/s and displayed a power function relation to alloy supercooling. The high speed videographic research of recalescence phenomenon indicated Johnson-Mehl-Avrami type transition kinetics for its rapid solidification process. As supercooling increases, the microstructures of primary HEB phase were refined conspicuously and exhibited an obvious solute trapping effect of the segregative Zr component. Meanwhile, the Vickers hardness of HEB phase displayed the rising tendency with supercooling.

Ultrafast charge-transfer in organic photovoltaic interfaces: geometrical and functionalization effects

Understanding the microscopic mechanisms of electronic excitation in organic photovoltaic cells is a challenging problem in the design of efficient devices capable of performing sunlight harvesting. Here we develop and apply an ab initio approach based on time-dependent density functional theory and Ehrenfest dynamics to investigate photoinduced charge transfer in small organic molecules. Our calculations include mixed quantum-classical dynamics with ions moving classically and electrons quantum mechanically, where no experimental external parameter other than the material geometry is required. We show that the behavior of photocarriers in zinc phthalocyanine (ZnPc) and C60 systems, an effective prototype system for organic solar cells, is sensitive to the atomic orientation of the donor and the acceptor units as well as the functionalization of covalent molecules at the interface. In particular, configurations with the ZnPc molecules facing on C60 facilitate charge transfer between substrate and molecules that occurs within 200 fs. In contrast, configurations where ZnPc is tilted above C60 present extremely low carrier injection efficiency even at longer times as an effect of the larger interfacial potential level offset and higher energetic barrier between the donor and acceptor molecules. An enhancement of charge injection into C60 at shorter times is observed as binding groups connect ZnPc and C60 in a dyad system. Our results demonstrate a promising way of designing and controlling photoinduced charge transfer on the atomic level in organic devices that would lead to efficient carrier separation and maximize device performance.

[Effect of hyperbaric oxygen therapy on antioxidant capacity in brains of rats after acute carbon monoxide poisoning]

OBJECTIVE

This study was designed to observe the antioxidant effects of hyperbaric oxygen (HBO) on brains of rats after acute carbon monoxide (CO) poisoning.

METHODS

Sixty-six Sprague-Dawley (SD) male rats were divided into three groups including control group, CO group and HBO group.Morris water maze experiments were used for monitoring cognitive function.Antioxidant capacities were evaluated by detecting T-AOC, GSH-PX, GR and CAT activities in the brain.

RESULTS

Compared with the control group (45±17, 43±14, 35±12, 34±11, 29±13) s and the HBO group (40±10, 39±6, 35±9, 31±11, 21±10) s, the CO group (57±5, 54±8, 52±8, 52±10, 46±8) s had the longer escape latency (P<0.05). Compared with the control group (51±6) s and the HBO group(40±10) s, the CO group (8±5) s had the shorter swimming time in I quadrant (P<0.05). Compared with the control group (1.25±0.40) U/mg and the HBO group(0.97±0.31, 0.97±0.39, 1.45±0.15, 1.40±0.25, 1.20±0.20) U/mg, the CO group (0.68±0.09, 0.45±0.17, 0.71±0.18, 0.69±0.29, 0.48±0.29) U/mg had the lower T-AOC activity of brain tissue.The GSH-PX activity (42±13, 106±46, 197±49, 173±42, 429±58) U/mg in the CO group decreased compared with the control group (182±53) U/mg and the HBO group (203±63, 325±86, 389±29, 385±100, 453±32) U/mg.GR activity (4.3±0.7, 2.6±0.5, 3.0±1.2, 1.8±0.8, 3.2±1.9) U/mg in the CO group decreased compared with the control group(14.5±3.0) U/mg and the HBO group (13.9±3.3, 4.3±1.0, 3.9±0.7, 4.8±0.9, 4.6±0.9) U/mg.CAT activity (1.6±0.8, 4.3±1.6, 3.9±1.0, 8.5±2.6, 5.4±1.7) U/mg in the CO group decreased compared with the control group(5.2±1.3) U/mg and the HBO group (5.2±2.2, 8.8±2.8, 5.3±1.0, 9.2±2.1, 14.1±3.8) U/mg.

CONCLUSIONS

HBO can improve the behavior of rats after acute CO poisoning.The antioxidant capacity in rat brain tissue after acute CO poisoning decreases, while after the HBO therapy, the antioxidant capacity in rat brain tissue can increase.