Responses of nitrogen and phosphorus resorption of understory plants to microscale soil nutrient hetero-geneity in Chinese fir plantation.

We compared the interspecific differences in leaf nutrient resorption of two dominant understory species (Lophatherum gracile and Oplimenus unulatifolius), and analyzed the correlations between the intraspecific efficiency of leaf nutrient resorption and nutrient properties of soil and leaves in Chinese fir plantation. The results showed high soil nutrient heterogeneity in Chinese fir plantation. Soil inorganic nitrogen content and available phosphorus content varied from 8.58 to 65.29 mg·kg-1 and from 2.43 to 15.20 mg·kg-1 in the Chinese fir plantation, respectively. The soil inorganic nitrogen content in O. undulatifolius community was 1.4 times higher than that in L. gra-cile community, but there was no significant difference in soil available phosphorus content between the two communities. Both leaf nitrogen and phosphorus resorption efficiency of O. unulatifolius was significantly lower than that of L. gracile under the three measurement bases of leaf dry weight, leaf area, and lignin content. Resorption efficiency in L. gracile community expressed on leaf dry weight was lower than that expressed on leaf area and lignin content, while resorption efficiency expressed on leaf area was the lowest in O. unulatifolius community. The intraspecific resorption efficiency was significantly correlated with leaf nutrient contents, but was less correlated with soil nutrient content, and only the nitrogen resorption efficiency of L. gracile had significant positive correlation with soil inorganic nitrogen content. The results indicated that there was significant difference in the leaf nutrient resorption efficiency between the two understory species. Soil nutrient heterogeneity exerted a weak effect on the intraspecific nutrient resorption, which might be attributed to high soil nutrient availability and potential disturbance from canopy litter in Chinese fir plantation.

New monoterpenes, diterpenes, and lignans from Abies recurvata.

From the aerial part of Abies recurvata, 62 miscellaneous chemical constituents were isolated including 6 new and 56 known ones. The new compounds comprised three monoterpenes, two diterpenes, and one lignan. Their chemical structures were characterized on the basis of various spectroscopic techniques. Dihydrodehydrodiconiferyl alcohol (35) showed the strongest inhibitory effects against lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells with an IC50 value of 66.4 µM.

Effect of different ionic liquids and organic solvents on the structural and physicochemical properties of cellulose-protein complexes extracted from Se-enriched peanut leaves.

Abundant cellulose and insoluble protein were contained in the Se-enriched peanut leaf residue, a by-product from leaf protein extraction. Ionic liquids (ILs) were used to extract the cellulose-protein complexes (CPCs) from Se-enriched peanut leaf residue. The effects of various ILs as extractants and organic solvents as regenerant on the physicochemical properties of CPCs were compared. The results showed that the yield of CPCs and recovery yield of [AMIM]Cl (1-allyl-3-methylimidazole chloride) were better than those of [BMIM]Cl (1-butyl-3-methylimidazolium chloride). Simultaneously, it could be seen from the infrared absorption peaks and secondary structure fitting results that [BMIM]Cl seemed stronger than [AMIM]Cl in destroying the secondary structure of CPCs. Scanning electron microscope (SEM) showed that the CPCs extracted by [BMIM]Cl were lamellate with holes on the surface, and the CPCs extracted by [AMIM]Cl were rough, almost without holes on the surface. Furthermore, the transmittance and tensile strength of the film which contained BA-CPC ([BMIM]Cl as extractant and acetonitrile as regenerant) film were better than those contained AA-CPC ([AMIM]Cl as extractant and acetonitrile as regenerant) film, which might be mainly because the types of ILs and regenerants affect the particle size of CPCs, thereby influencing the mechanical properties of the film.

Separation and on-line preconcentration by stacking and sweeping of charged analytes in the plant by microemulsion electrokinetic chromatography with nonionic surfactants.

A novel on-line technique for stacking and sweeping of long sample plugs with simultaneous determination of charged analytes in the plant (protocatechuic aldehyde, rosmarinic acid, danshensu, salvianolic acid B, and protocatechuic acid) by the nonionic microemulsion electrokinetic chromatography (MEEKC) is presented. The preconcentration efficiency provided about 9-28-fold for stacking and 7-14-fold for sweeping in the enhancements of LOD. The effects of oil phase, Brij-35 and buffer concentrations on stacking and sweeping efficiency were examined in order to optimize the two methods. In nonionic MEEKC, the effect of the type of oil and buffer contents on preconcentration mechanism is often sophisticated. This study had demonstrated that the oil type and buffer content in nonionic microemulsion indeed markedly altered the affinity of microemulsion with analytes. Finally, in comparison to the stacking method, the most apparent disadvantages of the sweeping method were the relatively high limits of detection and poor peak shapes.

A metabonomic approach to the diagnosis of oral squamous cell carcinoma, oral lichen planus and oral leukoplakia.

Early diagnosis of oral squamous cell carcinoma (OSCC) and precursor lesions is an attractive strategy to decrease patient morbidity and mortality, but presently there are no satisfied diagnostic approaches. This study proposed a metabonomics-based diagnostic approach for OSCC and its precancerous lesions, including oral lichen planus (OLP) and oral leukoplakia (OLK). Saliva samples were collected from patients and healthy donors, and HPLC/MS analysis was performed to acquire metabolic profiles. Diagnostic model was then constructed with hierarchical principal component analysis (HPCA) and discriminate analysis algorithms. The results indicate that metabolic profiling can properly describe the pathologic characteristics of OSCC, OLP and OLK. HPCA combined with kernel fisher discriminant analysis achieved 100% accuracy in diagnosis of test samples, which is superior to direct principal component analysis and other modeling algorithms. The metabonomic approach based on the integral investigation of oral metabolites enables the detection of OSCC and precancerous lesions on noninvasive saliva samples. The proposed approach is noninvasive, efficient and low-cost, and it can be developed as a promising method for population-based screening of cancers and precancers in the oral cavity.

[The recent development on age estimation].

The main methods of age estimation at present mostly rely on characteristic physical and chemical changes of skeleton, soft tissue, cells, biomacromolecules and the other substances. Because physiological changes of tissues and organs during growth are extremely complicated, all methods have their limitations. In practical, it is necessary to combine several methods together in order to improve the accuracy of age estimation. This article reviewed recent development on age estimation domestically and abroad and discussed advantage and disadvantage of different methods.

[Studies on the lignans from Patrinia scabra].

AIM: To study the lignans from Patrinia scabra Bunge. METHODS: The constituents were separated and purified by column chromatography with silical gel, RP-silical gel and Sephadex LH-20. Their structures were identified on the basis of spectral data (IR, MS, 1HNMR, 13CNMR, HMQC and HMBC). RESULTS AND CONCLUSION: A new lignan was obtained and its structure was elucidated as 4-[1-ethoxyl-1-(4-hydroxy-3-methoxy)benzyl]methyl- 2-(4-hydroxy-3-methoxy)benzyl-3-hydroxymethyl-tetrahydro-furan (2), along with three known lignans, lariciresinol (1), isolariciresinol (3) and nortracheloside (4).

[Role of biological protective dressing in microskin grafting in rabbit].

OBJECTIVE: To study the effect of biological protective dressing made from porcine peritoneum in covering wounds with microskin grafts. METHODS: Twenty New Zealand rabbits were divided into ten couples according to the random number table. Rabbits in each couple underwent surgery at the same time. A piece of full-thickness skin of 5 cm in diameter was removed symmetrically from the left and right sides of the back of each rabbit, thus forming two wounds with full-thickness skin defect. One fifth of one piece of skin of one rabbit was cut into tiny pieces of 0.2-0.5 mm in size (microskin). Then the microskin pieces were spread on the two wounds of the donor rabbit with the microskin/wound area ratio 1:10. The two wounds of each rabbit covered with microskin were divided into two groups according to the random number table. One wound was covered with biological protective dressing prepared with porcine peritoneum as experiment group, and the other was covered with the rest allograft in full size obtained from the other rabbit of each couple as control group. The general condition of wound was observed at post operation week (POW) 1-4. Wound healing rate was calculated at POW 3 and 4. Wound healing time was recorded. Specimens were harvested from wounds for histological observation at POW 1-4. Data were processed with paired t test. RESULTS: (1) At POW 1, the biological protective dressings were found to attach firmly to the wounds in experiment group without obvious inflammatory response; the allografts survived well on the wounds in control group. At POW 2, the coverings attached well to the wounds of both groups, but became drier and darker as compared with those at POW 1. At POW 3, some wounds of the two groups healed when the coverings desiccated and separated. At POW 4, all the wounds of both groups healed without obvious difference in appearance. (2) The wound healing rates of the experiment and control groups were respectively (92.8 ± 6.2)% and (91.3 ± 7.3)% (t = 0.54, P > 0.05) at POW 3 and (98.1 ± 2.3)% and (97.0 ± 4.6)% (t = 0.38, P > 0.05) at POW 4. (3) The wound healing time was (25.0 ± 3.9) d in experiment group and (24.8 ± 2.3) d in control group. The difference between them was not statistically significant (t = 0.82, P > 0.05). (4) Histological observation showed that wounds of the two groups were all infiltrated by inflammatory cells, and new blood vessels were observed at POW 1 and 2. The survived microskin proliferated under the coverings. At POW 3 and 4, the coverings on the wounds of two groups were gradually degenerated and became necrotic and separated from the wound beds, while the wounds underneath were re-epithelialized. CONCLUSIONS: The effect of biological protective dressing in covering wounds grafted with microskin is as good as that of the allograft, as they both help the auto-microskin proliferate and repair the wound. It could be considered to be new biological material for clinical application.

[Epidemiological features of hand, foot and mouth disease in China, 2008 - 2009].

OBJECTIVE: To clarify the seasonal and geographical difference and pathogen patterns so as to provide reference of prevention and control of the disease through analyzing the epidemic characteristics of reported hand-foot-mouth disease (HFMD) cases in China, 2008 - 2009. METHODS: We analysed the epidemiological data of HFMD from the Chinese national notifiable infectious diseases reporting system in 2008 and 2009. RESULTS: There were 488 955 and 1 155 525 reported HFMD cases in 2008 and 2009, in China, of which 1165 and 13 810 were severe and 126 and 353 were fatal, respectively. The notification rates were 50.09/10 million, 68.47/10 million and 59.04/10 million in high, medium and low latitudes areas, respectively. The epidemic periods in Medium and Low latitude were from 12 to 24 weeks in 2009, and in high latitude it was from 23 to 35 weeks. HFMD cases were concentrated mainly in 5 year-old or even younger children, accounted for 92.23% of the total cases. The incidence rate of two years old appeared to be the highest. The features of severe and death case concentrated in lower age groups were more evident, and the proportion of severe case and case fatality rate under 1 years old was higher than that in other age groups. We also noticed that with the increasing of age, the proportion of severe case and case fatality rate had a decreasing trend. There was a difference between the pathogens seen. The relative risk (RR) for an human enterovirus 71 (HEV71) isolate was higher among severe case than in common cases (RR = 1.82), whereas the RR for an EV71 isolate was higher among the death cases than in common cases (RR = 2.11). There was seasonal variation of pathogen composition. There were 477 clusters of cases from 2008 to 2009, of which 389 found in preschools, 47 in rural villages, outbreaks of clusters were mainly from April to July. CONCLUSION: The HFMD epidemics was increasing in 2009. The epidemic of HFMD in different latitudes area and seasons was different. Children of five year old or under were the major population groups at risk, of HFMD. The younger ones had higher risk of becoming severe and death cases. HEV71 and coxsackievirus A16 were both the major etiologic agents of HFMD. The preschool and rural villages were the main settings of clusters of cases.

The study on pervaporation behaviors of dilute organic solution through PDMS/PTFE composite membrane.

As an energy-efficient alternative to distillation, pervaporation has been widely combined with fermentation to remove organic compounds from their dilute solutions in a fermentation broth. In this work, the organic permselective composite membrane is prepared by coating polydimethylsiloxane (PDMS) cross-linked with n-heptane on the substrate of polytetrafluoroethylene(PTFE) membrane. The separation behavior is studied in different dilute organic solutions, which include acetone dilute solution, butanone dilute solution, cyclohexanone dilute solution, ethanol dilute solution, isopropanol dilute solution, n-butyl alcohol dilute solution, acetic acid dilute solution, and ethyl acetate dilute solution. Most of these solutions are main reaction products or by-products from fermentation process. The effects of solubility of organics in the membrane, molecular weight, and polarity of the organics on the pervaporation performance are investigated. The effects of operating temperature and organic concentration in the feed solutions on the performance of composite membrane are studied as well. The experimental results show that molecular volume has less influence than solubility and molecular polarity for these organic solvent. The selectivity of PDMS membrane to ethyl acetate is relative high due to good solubility and diffusion of ethyl acetate molecules in polymer.

Lipase immobilized on the hydrophobic polytetrafluoroethene membrane with nonwoven fabric and its application in intensifying synthesis of butyl oleate.

The synthesis of butyl oleate was studied in this paper with immobilized lipase. Five types of membrane were used as support to immobilize Rhizopus arrhizus lipase by following a procedure combining filtration and protein cross-linking. Results showed that hydrophobic polytetrafluoroethene membrane with nonwoven fabric (HO-PTFE-NF) was the favorite choice in terms of higher protein loading, activity, and specific activity of immobilized lipase. The factors including solvent polarity, lipase dosage, concentration, and molar ratio of substrate and temperature were found to have significant influence on conversion. Results showed that hexane (logP = 3.53) was a favorable solvent for the biosynthesis of butyl oleate in our studies. The optimal conditions were experimentally determined of 50 U immobilized lipase, molar ratio of oleic acid to butanol of 1.0, substrate concentration of 0.12 mol/L, temperature of 37 °C, and reaction time of 2 h. The conversion was beyond 91% and decreased slightly after 18 cycles. Lipase immobilization can improve the conversion and the repeated use of immobilized lipase relative to free lipase.

[CT and MRI features of peripheral primitive neuroectodermal tumor].

BACKGROUND & OBJECTIVE: It's difficult to distinguish peripheral primitive neuroectodermal tumor (PNET) from other small round cell tumors such as Ewing's sarcoma by histological examination. This study was to analyze the CT and MRI features of peripheral PNET. METHODS: The CT and MRI records of 7 patients with pathologically proved peripheral PNET were reviewed. RESULTS: The tumors were located in the left ala nasi, right lower jaw bone, left chest wall, right chest wall, left spermatic cord, paraspinal, and lumbar vertebral canal. The tumors in soft tissue showed resembled non-calcified, ill-defined soft tissue masses with cystic or necrotic areas on CT images, with heterogeneous enhancement on contrast images. The tumors in the bone showed lytic lesions with large soft tissue masses on CT images. The tumors in the paraspinal and vertebral canal showed well-defined soft tissue masses without involving cord and cauda equine on MRI, and showed isointensity or hypointensity on T1WI and isointensity or hyperintensity on T2WI. CONCLUSIONS: The imaging features of peripheral PNET are non-specific. CT and MRI are useful in delineating the extent, finding distant metastasis, predicting respectability and monitoring treatment of peripheral PNET.