[Responses of canopy stomatal conductance of Platycladus orientalis to soil water under water control.] / æŽ§æ°´æ¡ä»¶ä¸‹ä¾§æŸå† å±‚æ°”å­”å¯¼åº¦å¯¹åœŸå£¤æ°´çš„å“åº”.

A water-controlled experiment with four treatments (no rain, half raining, natural raining and double raining) was carried out in a Platycladus orientalis forest. The factors including soil water content (SWC), precipitation, sap flow density (Js), leaf area index (LAI), vapor pressure deficit (VPD) were monitored during August 2016 to August 2017. We further analyzed the response of canopy stomatal conductance (gs) to changes of SWC. The results showed that the SWC of plots (half, natural and double raining) showed a positive correlation with precipitation, and the range of SWC was 4.9%-16.0%, 7.2%-22.9%, 7.4%-29.6%, respectively. The SWC in the plot with no rain decreased by 50% from August to October. The daily gs reached a peak of 166.64 mmol·m-2·s-1 at 14:00 in July, which was significantly higher than other months. A bimodal phenomenon occurred. The daily gs reached a peak of 54.1 mmol·m-2·s-1 at 12:00 in January. Under the three rain plots, diurnal variation of gs and SWC showed a negative quadratic correlation. The SWC corresponding to the peak of gs was 8.5%, 12.5% and 18.5%, respectively, close to the annual average SWC. Sensitivity (δ) of gs to VPD /reference canopy stomatal conductance (gsref) was more than or equal to 0.6 in different water-controlled plots, indicating that soil water condition was more suitable for water demand of P. orientalis. When SWC was between 3.7% and 7.5%, the δ and gsref increased rapidly, indicating that stomata had better regulation ability, and that plant stomata was more sensitive to VPD. When SWC increased to 11%, SWC alteration did not affect the response sensitivity of gsrefand gs to VPD. There might be a SWC threshold value for the adaptation of P. orientalis. By closing or reducing stomatal aperture, leaf water potential decreased, P. orientalis could adapt to excessive VPD and avoid excessive transpiration, which was more effective in regulating transpiration.

[Characteristics of canopy stomatal conductance of Platycladus orientalis and its responses to environmental factors in the mountainous area of North China]. / åŽåŒ—å±±åŒºä¾§æŸå† å±‚æ°”å­”å¯¼åº¦ç‰¹å¾åŠå ¶å¯¹çŽ¯å¢ƒå› å­çš„å“åº”.

Canopy stomatal conductance (gs) is an important biological parameter to measure water vapor flux in canopy atmosphere interface. Exploring characteristics of canopy stomatal conductance and its responses to environmental factors can offer theoretical evidence for conducting mechanism based study of vapor exchange process in forest canopy. SF-L thermal dissipation probe was adopted to measure sap flow density (Js) of Platycladus orientalis in 2014. The environmental factors including photosynthetically active radiation (PAR), vapor pressure deficit (VPD) and air temperature (T) were simultaneously observed. The canopy stomatal conductance was calculated, and the responses of gs to environmental factors were analyzed. The results showed that the daily variation of sap flow density was of two peak pattern curve, and the Js in growing season was higher than in non-growing season. And the bigger DBH was, the higher Js would be. The daily variation of canopy stomatal conductance was similar to the canopy transpiration of per leaf area (EL), which was of two peak pattern curve. The gs and EL in growing season were higher than those in non growing season. The canopy stomatal conductance and air temperature presented parabolic relation, and gs reached peak valley at around 10 ℃. Taking the value of 400 µmol·m-2·s-1 as the PAR thre shold, when PAR was under this threshold, gs was positively correlated with PAR. When PAR was beyond this threshold, the correlation between gs and PAR would be small. The relationship between canopy stomatal conductance and vapor pressure deficit was negative logarithmic function. As VPD increasing, gs decreased gradually. Higher air temperature and photosynthetically active radiation, and lower vapor pressure deficit contributed to higher canopy stomatal conductance of P. orientalis and could promote greater canopy transpiration.

Efficient Regioselective Synthesis of the Crotonyl Polydatin Prodrug by Thermomyces lanuginosus Lipase: a Kinetics Study in Eco-friendly 2-Methyltetrahydrofuran.

Bio-based solvents have recently been discussed as sustainable green and promising alternatives to conventional organic media for enzymatic processes. In this paper, highly regioselective synthesis of the 6″-O-crotonyl-polydatin catalyzed by Thermomyces lanuginosus lipase (TLL) in biomass-derived 2-methyltetrahydrofuran (2-MeTHF) was successfully performed for the first time. The results indicated that TLL lipase displayed significantly improved catalytic performance in 2-MeTHF than in other traditional solvents. Under the optimal conditions, the initial reaction rate, 6″-regioselectivity, and maximum substrate conversion were as high as 12.38 mM h(-1), 100 %, and 100 %, respectively. Moreover, further investigations on the operational stability, kinetic parameters like V max, K m, V max/K m, and E a revealed that 2-MeTHF exhibited excellent biocompatibility and rendered the greener process of the enzymatic acylation.

IR spectrum simulation of molecular structure model of Shendong coal vitrinite by using quantum chemistry method.

The structure of coal needs to be understood from a molecular point of view for clean, effective and high value-added utilization of coal. In the literature, molecular structure model of Shendong coal vitrinite (SV) was established by the authors on the basis of experimental results of ultimate analysis and 13C NMR, and the calculated 13C NMR spectrum of SV model was consistent with the experimental spectrum. In order to further verify the accuracy of SV structure model established by the authors, the infrared spectrum of SV structure model was calculated using quantum chemistry semi-empirical VAMP in this thesis. The results showed that the peak shape of calculated IR spectrum of SV structure model was similar to the experiment's, but the wave number of calculated IR spectrum was obviously higher than that of experimental spectrum. According to the calculated results for model compounds by using the same method, calculated vibrational frequency was higher than that of experiment for the same functional groups. Hence, the calculated IR spectrum should be corrected. After correction the calculated IR spectrum of SV structure model matched well with the experimental spectrum. In other words, the SV structure model can truly reflect the structure characteristics of SV.

Investigation of the relationship between chromobox homolog 8 and nucleus pulposus cells degeneration in rat intervertebral disc.

Here, we aimed to investigate the expression of chromobox homolog 8 (CBX8) in nucleus pulposus (NP) cells from rat intervertebral disc (IVD) and its function in DNA damage and repair. NP cells were isolated from healthy rat IVD for immunohistochemistry staining. Small interfering RNA (siRNA) of CBX8 was applied for gene silencing, and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to determine mRNA levels of CBX8, type II collagen, and proteoglycans. Cell proliferation and cell cycle were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony-forming assay, and flow cytometry. Hydrogen peroxide (H2O2) was added to simulate DNA oxidative damage, and expression of CBX8 was examined using RT-PCR and Western blot. After five passages, mRNA levels of type II collagen and proteoglycans decreased but that of CBX8 increased. When CBX8 was silenced by siRNA, the expressions of CBX8, type II collagen and proteoglycans declined, and the cell growth was inhibited. Besides, cell cycle was slowed down as most cells were arrest in G0/G1 phase. Furthermore, CBX8 expression went up responding to DNA oxidative damage caused by H2O2. The data indicated that CBX8 plays important roles in cell proliferation and DNA damage. Cell proliferation and cell cycle were stimulated by CBX8, which may be associated with INK4A-ARF pathway. Moreover, CBX8 plays a role in DNA damage which made it a potential gene therapy target for treatment of disc degeneration.

[The clinical results of minimally invasive transforaminal lumbar interbody fusion for lumbar spinal stenosis with lumbar instability].

OBJECTIVE: To investigate the clinical results of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for lumbar spinal stenosis with lumbar instability. METHODS: Retrospective study was done on 42 cases of lumbar spinal stenosis with lumbar instability treated with bilateral decompression via unilateral approach and MIS-TLIF through an expandable tubular retractor from March 2010 to January 2011. There were 18 males and 24 females, and mean age was 61.7 years (rang, 48 - 79 years). The level of surgery was L(3-4) in 4 patients, L(4-5) in 26 patients, and L(5)-S(1) in 12 patients. All patients had symptoms of intermittent claudication. And 24 patients had symptoms of lower extremity pain and numbness in one side, and 18 patients had same symptoms in both legs. Operation time, intra-operative bleeding, postoperative hospital stay and complications were recorded. Visual analogue scale (VAS) scores for low back pain and leg pain were recorded before and after surgery. Oswestry disability index (ODI) scores were also recorded before and after surgery. The Bridwell criterion was used for evaluating the interbody fusion, and the MacNab criterion was used for assessment after surgery. RESULTS: The mean operative time was 150.4 minutes (range, 120 - 170 minutes), and mean blood loss was 147.1 ml (range, 50 - 400 ml). The hospitalization time after surgery was 5 - 18 d, an average of 8.8 d. All cases were followed-up for 6 - 14 months (average 11 months). VAS score of low back pain before surgery was 7.3 ± 1.0, and were 2.9 ± 0.8 and 2.0 ± 0.8 at three months after surgery and the last follow-up respectively. VAS score of leg pain before surgery was 7.9 ± 0.7, and were 2.0 ± 0.5 and 1.0 ± 0.7 at three months after surgery and the last follow-up respectively. ODI score was 75% ± 6% before surgery, were 16% ± 6% and 12% ± 5% at three months after surgery and the last follow-up respectively. VAS and ODI scores showed statistically significant improvements (t = 3.110 - 56.323, P < 0.01). There were 40 cases were grade I and II, according to the Bridwell criteria. The clinical results were excellent in 16 cases, good in 22 cases and fair in 4 cases to the MacNab criteria at the final follow-up. CONCLUSIONS: MIS-TLIF is an ideal surgical method for single segment lumbar spinal stenosis with lumbar instability, but close attention should be paid to specific patients, surgeons and hospitals.

[Micro-FTIR study on structure of macerals from Jurassic coals in Northwestern China].

Jurassic coal in Northwest China is rich in resources and it is a necessary premise to reveal the chemical structure characteristics of the coal macerals in this region before the coal is put into reasonable and efficient use. Micro-FTIR technique was used to investigate the chemical composition and structures of vitrinite semifusinite and fusinite from Jurassic coal in Northwestern China. The results show that vitrinite and semifusinite have more aliphatic hydrogen, but fusinite has more aromatic hydrogen and C=O structure. The aliphatic hydrogen in semifusinite is higher than that in fusinite and it is this structure characteristic of semifusinite that led to the richer inertinite but higher reactivity of the Northwestern China coal. Not only vitrinite but also semifusinite and fusinite with weaker reducibility have less aliphatic hydrogen and more C=O structures than those with stronger reducibility. The different intensity of oxidation in the process of coalification is one of the causes that led to different type of reducibility.

[Development of a new biosensor for biochemical oxygen demand].

OBJECTIVE: To use a new kind of fixing material, i.e. Sol-Gel organic-inorganic hybridized material to immobilize bacterium to detect Biochemical oxygen demand quickly. METHODS: The biosensor was fabricated using a thin film in which Hansenula anomala was immobilized by sol-gel and an oxygen electrode. The optimum measurement for biochemical oxygen demand was at pH 7.0; 28 degrees C; response time 3 - 12 min. Pure organic compound, sewage and rate of recovery were detected with the biosensor. RESULTS: It shows that the BOD biosensor can be used to detect many organic compounds such as amino acid, glucide. It is suitable to monitor sewage and industrial waste water which has low level alcohols and phenols. The microbial membrane can work 3 months and remain its 70% activity. It is measured that the rate of recovery of BOD is between 90% to 105% in sewage. CONCLUSION: The study confirmed the effectiveness and usefulness of BOD sensor, which is quick, convenient, low cost and reliable with little interference.