Practical semi-quantum key distribution with one-way key and one basis.

Semi-quantum key distribution (SQKD) protocols are used to distribute secret keys between a quantum party and a classical party. However, existing SQKD protocols rely on two-way communication, and may still be vulnerable to Trojan horse side-channel attacks where Eve sends her own photon into a receiver's apparatus and measures the reflected photon to estimate the key. In this paper, we propose a practical SQKD with one-way key. This requires that the single photons travelling through the one-way channel are used to encode bit information, and the returned photons are used to quantify Eve's information, thus reducing the security analysis of the Trojan horse attack in SQKD. Meanwhile, our protocol with one basis enjoys security advantage in practical SQKD systems when source flaws are taken into account. In particular, the present protocol is secure under practical conditions when weak coherent pulses (WCP) are used. Our simulation results show that the protocol using WCP can distribute secret keys over a distance of 110 km without decoy states.

Counterfactual quantum key distribution with untrusted detectors.

Compared with the traditional BB84 protocol, the counterfactual quantum key distribution (QKD) does not rely on any signal travelling in the quantum channel, and therefore can present a security advantage where Eve cannot fully access signal. However, the practical system may be damaged in a scenario where the devices are untrusted. In this paper, we analyze the security of counterfactual QKD in untrusted detectors scenario. We show that the requirement to disclose "which detector clicked" has become the main loophole in all counterfactual QKD versions. An eavesdropping scheme which is similar to the memory attack on device-independent QKD could break its security by exploiting detectors' imperfections. We consider two different counterfactual QKD protocols and analyze their security against this major loophole. One is a modified Noh09 protocol, which would be secure in untrusted detectors context. Another is a variant of counterfactual QKD with high efficiency (Phys. Rev. A 104 (2021) 022424) against a series of detectors side-channel attacks as well as against other attacks that exploit detectors imperfections.

[Quantitative characteristics and distribution pattern of living and dead standing trees of secon-dary Picea forest in Guandi Mountain, northern China]. / å ³å¸å±±äº‘æ‰æ¬¡ç”Ÿæž—æ´»ç«‹æœ¨å’Œæž¯ç«‹æœ¨çš„æ•°é‡ç‰¹å¾ä¸Žåˆ†å¸ƒæ ¼å±€.

Based on the survey data from a 4 hm2 secondary Picea forest plot in the Pangquangou Nature Reserve, Guandi Mountain, Shanxi Province in 2010 and 2015, we analyzed the quantitative characteristics, distribution pattern, and correlation of living and dead standing trees during five years from four aspects, including species composition, diameter class structure, spatial pattern, spatial correlation between different diameter classes of living standing trees and dead standing trees, and intercorrelation between different diameter classes of dead standing trees. The results showed that there were 25811 living standing trees with DBH≥1 cm in the plot in 2010, belonging to 30 species, 22 genera, and 11 families. The distribution of individual diameter class was an inverted "L" type, and the number of individuals decreased in a fracture pattern with the increases of diameter class. During the five years (2010-2015), a total of 2145 dead standing trees were formed, involving 12 species, 10 genera, and 5 families. Most of the dead standing trees were distributed in diameter of 5-10 cm. At the scale of 0-50 m, the spatial distribution of living and dead standing trees was generally similar, indicating that the spatial pattern of dead standing trees was limited by that of living standing trees to some extent. The spatial correlation analysis of each diameter class of dead standing trees and living standing trees showed that with the increases of individual diameter class of trees, the intensified competition for space resources might be the main reason for the generation of dead standing trees. With the increases of diameter class of dead standing trees, the spatial correlation between living and dead standing trees was weakened to varying degrees, indicating that environment might be the key factor for the formation of large diameter class of dead standing trees. For the the dead standing trees, there was an obvious positive correlation between 5 cm≤DBH<20 cm dead standing trees and DBH<5 cm dead standing trees, between 10 cm≤DBH<20 cm dead standing trees and 5 cm≤DBH<10 cm dead standing trees, and between DBH≥20 cm dead standing trees and 5 cm≤DBH<20 cm dead standing trees. Our results indicated that dead standing trees would impact the subsequent dying of living standing trees.

[Spatial pattern and interspecific association of tree species in coniferous and deciduous broad-leaved mixed forest under different disturbance intensities]. / ä¸åŒå¹²æ‰°å¼ºåº¦ä¸‹é’ˆé˜”æ··äº¤æž—æ ‘ç§ç©ºé—´æ ¼å±€åŠç§é—´å ³è”æ€§.

We explored the effects of disturbance densities on the spatial pattern and the association of tree species in the coniferous broadleaved mixed forest in Pangquangou Nature Reserve of Guandi Mountain. Using three factors including canopy density, stand density and number of stumps, we classified the disturbance intensities of different forest stands into three levels, non-disturbance, moderate disturbance, and severe disturbance. The spatial distribution pattern and the association of different tree species were analyzed by spatial point pattern K2 function. The results showed that the diameter distribution of trees in undisturbed plots was inverted 'J' type, while that of moderate disturbance and serious disturbance plots was under bimodal curve distribution. The stand distribution pattern showed a small-scale aggregated distribution under undisturbed and moderately distur-bance, and a random distribution under heavy disturbance. At the small scale, the coniferous and broadleaved species showed no correlation in undisturbed stands, were positively correlated in moderately disturbed stands, and negatively correlated in seriously disturbed stands. At large scale, they were no correlated in both moderately and seriously disturbed stands. The results suggested that abundance of trees with small diameter in the forests was negatively with disturbance intensity, which led to the lower degree of intraspecific aggregation at small scale. Meanwhile, appropriate levels of disturbance would benefit the collaborative use of environmental resources for trees. Our results revealed the impacts of disturbance density on forest community structure and could provide theoretical basis for forest management.

Spatial associations between tree regeneration and soil nutrient in secondary Picea forest in Guandi Mountains, Shanxi, China.

According to the technical specifications of CTFS (Center for Tropical Forest Science), 190 sampling points of 4-hm2 plot (GDS plot) in Guandi Mountains of Shanxi Province, China were investigated to examine the spatial distribution pattern of seedlings and 14 soil indicators, including pH value and nutrient indicators. We analyzed the spatial associations between tree regeneration and soil nutrients, explored the mechanism of tree regeneration pattern of secon-dary Picea forest. The results showed that more seedlings survived in the patches with low contents of available N, available K, available Cu, available Fe, available Mn, available Ni and available Zn. Besides available K, the negative correlation between the other six soil nutrient factors and the number of regeneration seedlings of the Ⅱ (2.5 cm

[Spatial distribution patterns and associations of typical tree species in different regions.] / ä¸åŒåŒºåŸŸå ¸åž‹æ ‘æœ¨çš„ç©ºé—´åˆ†å¸ƒæ ¼å±€åŠå ³è”æ€§.

Based on the monitoring data from the plots of Changbai Mountains in the temperate zone (CBS), Guandi Mountain in the warm temperate zone (GDS), Heishiding Mountain in the subtropical zone (HSD), we analyzed the spatial distribution of tree species from three families (Pinaceae, Fagaceae, Rosaceae) and their correlation using paired correlation function g(r). The results showed that the individual number and size class structural characteristics of the trees from the three families varied among different regions. Pinaceae had high population density and a bimodal size-class structure in GDS plot but a small number and skewed normal size-class structure in CBS and HSD plots. Fagaceae had low abundance and a bimodal, skewed normal size-class structure respectively in CBS and GDS plots but a large number and an inverted J-type diameter distribution in HSD plot. Rosaceae had high abundance and a L-type size structure in GDS plot but relatively low abundance and a L-inverted and J-type size class distribution respectively in HSD and CBS plots. The trees from those three families showed different spatial distribution patterns in three different forest plots. The large size class individuals of Pinaceae were regularly distributed at small scale in CBS and GDS plots but aggregated in HSD plot, the middle and small size class ones were consis-tently aggregated in three plots. Fagaceae trees were mainly characterized by large size class and approximately distributed at random in CBS plot, but mainly characterized by middle or small size class and aggregated in GDS and HSD plots. The trees of Rosaceae were aggregated in three plots. The aggregation degree of trees from three families decreased with the increases of spatial scales. The large size class individuals of Fagaceae were negatively associated at small scale or uncorrelated with Pinaceae trees in CBS and HSD plots. The middle or small size class individuals of Fagaceae were negatively associated with Pinaceae ones in CBS and GDS plots but positively associated with Pinaceae ones in HSD plot. Trees from Pinaceae were negatively correlated with trees from Rosaceae in three plots. The middle or small size class individuals of Fagaceae were positively correlated with individuals of Rosaceae in CBS and GDS plots but negatively correlated with trees of Rosaceae in HSD plot. In conclusion, the spatial distribution patterns and associations of the trees from three families changed with the size class, research scale and had different patterns among three plots.

[Species composition, structure and spatial distribution of secondary cold-temperate Picea forest in Guandi Mountain, China]. / å ³å¸å±±å¯’æ¸©æ€§äº‘æ‰æ¬¡ç”Ÿæž—æ ·åœ°æ ‘ç§ç»„æˆã€ç»“æž„å’Œç©ºé—´åˆ†å¸ƒ.

The secondary Picea forest is one of the dominant vegetation types in Guandi Mountain. It's also the representative type of evergreen cold-temperate coniferous forests in subalpine region of north China. A 4 hm2 fixed monitoring Picea forest plot was established in Pangquangou Nature Reserve, Guandi Mountain (GDS plot) to better understand the basic characteristics such as species composition, community structure and its potential ecological process and mechanisms. We analyzed species composition, structure and spatial distribution of sample forest based on the first background survey data in this paper. The results showed that a total of 30 woody plant species existed in the sample area, which belonged to 11 families, 22 genera. The total individual number (including branches) was 26218 (independent individual number was 10266). Floristic composition in the region was defined as north temperate elements. Big differences of individual number, average diameter at breast height (DBH) and basal area among different species caused significant community layering effect, and the dominant species in each layer was obvious. Size-class structure of species showed bimodal skewed normal distribution at the canopy layer, approximate normal distribution at the subtree layer, and 'L' type distribution at the shrub layer. Spatial distribution of the dominant tree species such as Picea wilsonii and Larix principis-rupprechtii showed different pattern features with the changing size class, whether in individual number or in aggregation degree. Compared with the above two species with the same size class, a large number of L. principis-rupprechtii with DBH≥30 cm aggregated in the center of sample plot, but few P. wilsonii individuals with DBH≥30 cm occurred in the plot and had no clustering distribution. Only a few L. principis-rupprechtii with DBH≤10 cm occurred in the plot with a scattering distribution, and a large number of P. wilsonii with DBH≤10 cm aggregated in the center of the plot. There were also many P. wilsonii individuals with DBH≤10 cm distributed in the northwest area of the plot, but Betula albo-sinensis individuals with DBH≤10 cm mostly distributed in the southeast area of the plot. Shrub species such as Cotoneaster acutifolius, Spiraea pubescens and Lonicera szechuanica also showed heterogeneous spatial distribution. Species distribution pattern was affected by habitat conditions, and related to its own development, regeneration traits and ecological habits.

[Characterization of Cr Tolerance and Accumulation in Lolium perenne L. and Pharibitis purpurea(L.) Voigt].

Considering the serious pollution of heavy metal-chromium (Cr) in soil, there is an urgent need for effective selection of Cr-tolerant plant species. In order to gain fundamental insights into the tolerance and accumulation capabilities of Lolium perenne L. and Pharibitis purpurea(L.) Voigt under Cr stress, a pot experiment was conducted to investigate their growth, physiology and accumulation characteristics under Cr(Ⅲ) and Cr(Ⅵ) stress. The results showed the growth parameters could intuitively reflect the toxicity levels of Cr for plants. For instance, a low-level Cr(Ⅲ) (<250 mg·kg-1) in soil was good for plant growth as indicated by the significant elevation of plant height, root length and biomass in L. perenne (P<0.05). However, Cr(Ⅵ) at all concentrations (≥25 mg·kg-1) in the soil inhibited the growth of both plant species, and the root length was particularly sensitive to the toxicity of Cr. The physiological parameters of plant represented both the toxicity of Cr and the tolerance of plants under Cr stress. A decrease of root activity and an increase of malonaldehyde content were observed under Cr stress, which indicated the physiological metabolism of plants was disturbed. In the presence of both Cr species, the proline content increased, which served as an indicator for both high Cr toxicity and increase of osmotic balance in plants. A rise in SOD and POD activity reflected the defense ability of plants against oxidative stress caused by Cr. In addition, the Cr-accumulation related parameters were the major standards for tolerant species selection. The Cr(Ⅵ) accumulation capacities of both plant species were greater than their Cr(Ⅲ) accumulation capacities. The maximum accumulation amounts of L. perenne and P. purpurea reached 957.4 mg·kg-1 and 743.3 mg·kg-1 in roots and 394.7 mg·kg-1 and 340.4 mg·kg-1 in shoots, respectively. In comparison with P. purpurea, L. perenne displayed a stronger Cr accumulation capacity in roots with a maximum bioaccumulation factor of 15.55. However, the transport ability of P. purpurea was superior to L. perenne. All of the parameters demonstrated that both L. perenne and P. purpurea could be used as alternative plants for phytoremediation of Cr-contaminated soil.

[Variations in leaf C, N, P stoichiometry of Quercus acutissima provenance forests.] / éº»æ Žç§æºæž—å¶ç‰‡ç¢³ã€æ°®ã€ç£·åŒ–å­¦è®¡é‡ç‰¹å¾çš„å˜å¼‚.

In order to explore the variations in leaf stoichiometry based on the method of forest tree breeding, we determined the leaf carbon (C), nitrogen (N), phosphorus (P) stoichiometry among 29 Quercus acutissima provenances grown at 3 sites. The results indicated that the site (environment) effect was statistically significant on leaf stoichiometry, with 13.2%-66.7% of the total variations accounted for leaf C, N, P, C/N, C/P and N/P, while the provenance effect was insignificant and only accounted for 2.9%-11.0% of total variations for leaf stoichiometry. The leaf N and C/N, N and N/P, P and C/P, P and N/P were significantly correlated, and the common standardized major axis slope was also observed among three sites and two provenance groups. It could be concluded that the leaf stoichiometry of Q. acutissima, was mainly determined by its growing environment, due to the similar C, N and P biochemical pathways at species level. The stable correlation coefficients among sites and provenances implied the coupling ratios of leaf stoichiometry were independent of environment and provenance, which supported the leaf stoichiometric homeostasis.

[Investigation about prevention behavior for dust workers in machinery, ceramic, and metallurgy industry].

OBJECTIVE: The purposes of this thesis were to study the behavior about workers exposed to dust and provide scientific basis for health promotion. METHODS: We designed a questionnaire and carry it on the 746 dust workers in the 3 representative corporations of Machinery, Ceramic, and Metallurgy Industry. All data were input into computer. And a database was established with Excel. SPSS11.5 statistical analysis software was used to analyze the influence on protecting behavioral between the application of qualifications, different jobs, training or protection, and other aspects etc. RESULTS: The rates were 94.4% and 75.3% about the regular physical examination and requirements for protective equipment. The rate of choosing an effective way of protection was generally low (15.4%). There was significant difference for among different educational background workers (P < 0.01). The rates of choosing an effective way of protection (20.3%), the regular physical examination (98.3%) and requirements for protective equipment (86.4%) in the dust workers who participated in the training of dust protection were superior than those who did not participated in the training. There was the significant difference (P < 0.05, P < 0.01). There was the significant difference for the rate of effective way of protection, regular physical examination, and requirements for protective equipment among the different corporations (P < 0.05). CONCLUSIONS: Dust workers' using rate about the choosing an effective way of protection was generally low in Machinery, Ceramic, and Metallurgy Industry. Those who were not educated had a lower using rate about the protection behavior, regular physical examination, and requirements for protective equipment than those educated.

[Spatial relevance between natural regeneration of Picea and heterogeneity of soil available nitrogen in Guandi Mountain].

By using geostatistic and pattern analysis methods, this paper studied the spatial pattern of Picea seedlings in naturally regenerated conifer (Picea) and mixed (Picea-Populus-Betula) forests in Guandi Mountain of Shanxi Province, China. The spatial distribution of soil nitrogen was also quantified by semivariogram analysis. To understand the effects of spatial heterogeneity of soil nitrogen on the regeneration of Picea seedlings, the relationships between the regeneration pattern of the seedlings and the spatial distribution of soil nitrogen were investigated by using GIS superposition and statistical analysis. In conifer stands, the distribution of Picea seedlings appeared as a patch pattern and was auto-correlated; while in mixed stands, the distribution was of gathering distribution pattern controlled by random factors. In the Picea stands with relatively low soil nitrogen content, the spatial distribution of soil available nitrogen was significantly heterogeneous and auto-correlated; whereas in the mixed stands with high nitrogen content, the distribution of soil available nitrogen showed random heterogeneity. In the conifer stands, the spatial correlation between Picea seedlings regeneration pattern and soil available nitrogen distribution was significant, regenerating more seedlings in the patches with higher NH4(+) -N concentration; while in the mixed stands, the correlation was not significant.

[The frequency and function of FoxP3+ regulatory T cell in patients with acute hepatitis B].

AIM: To investigate the dynamic variety of frequency and function of FoxP3+ regulatory T cells in patients with acute hepatitis B (AHB). METHODS: Peripheral blood mononuclear cells (PBMCs) from 15 AHB patients at acute phase (week 1 of illness), convalescent phase (primary occurrence of both ALT level normalization and HBsAg negative conversion), resolved phase (at least 8 weeks after both ALT normalization and HBsAg seroconversion, and 15 health subjects were analyzed for FoxP3 (Forkhead/winged helix transcription factor) mRNA expression in MACS magnetic beads-purified CD4+ T cells by real-time RT-PCR assay. The effects of Treg cells on the proliferation of CD4+ CD25- T cells were examined by a 3H-thymidine incorporation assay. RESULTS: AHB patients presented a significantly higher FoxP3 mRNA expression at convalescent phase than acute phase (t= -6.04, P<0.01) and resolved phase (t=4.45, P<0.01), and healthy controls (t=3.44, P<0.01). We also observed that the suppression efficiency of Treg cells on proliferation of CD4+ CD25- T cells was lower at acute phase than convalescent phase (t= -5.30, P<0.01) and resolved phase (t= -3.20, P<0.05), but there was no significant difference between healthy controls and any phase of AHB. CONCLUSION: AHB patients presented lower circulating Treg frequency and suppression function at acute phase, and both of them are increase at convalescent phase, and then return to normal level along with disease resolved. This follow-up study furthers our understanding of Treg's role in immunopathogenesis of hepatitis B.

Molecular evolution of Fome lignosus laccase by ethyl methane sulfonate-based random mutagenesis in vitro.

In order to improve the laccase activity, mutant libraries are constructed through ethyl methane sulfonate-based (EMS) random mutagenesis. Mutagenesis improved expression 3.7-fold to 144 mgl(-1) laccase in yeast, together with a 1.4-fold increase in K(cat). Thus, the total activity is enhanced 5-fold for 2,2'-azino-bis 3-ethylbenzothiaoline-6-sulfonic acid (ABTS). In the presence of 0.6mM copper, the highest activity value reached 30 Uml(-1) after a 3-day cultivation at a temperature of 30 degrees C(.) In comparison with the wild type, the best mutant enzymatic properties (K(m) for ABTS and guaiacol, thermo- and pH stability, optimal pH) are not changed. Moreover, amino acid sequence analysis indicates that there are four substitutions in the best mutant laccase (Gly160Asp, Ala167Thr, Gly174Asp, and Glu234Gly). The best mutant laccase model showed that the Gly160 and Ala167 are to be found near the water channel; especially the distance of Ala167 to the Cu3a is 14.46 A. This implies that it is likely involved in the formation of water channel and that it helps facilitate the easy incoming and outgoing of water.

Effects of host plants on insecticide susceptibility and carboxylesterase activity in Bemisia tabaci biotype B and greenhouse whitefly, Trialeurodes vaporariorum.

Bemisia tabaci (Gennadius) biotype B and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood), have become serious pests of cotton and vegetable crops in China since the early 1990s. In recent years, however, B. tabaci have broken out more frequently and widely than have T. vaporariorum. The B. tabaci biotype B has also developed higher resistance to several insecticides. Here, the effects of four different host plants on the insecticide susceptibility of B. tabaci biotype B and T. vaporariorum have been compared. The LC(50) values of imidacloprid, abamectin, deltamethrin and omethoate in T. vaporariorum reared on cucumber were significantly higher than those in B. tabaci (the LC(50) values in T. vaporariorum were respectively 3.13, 2.63, 2.78 and 6.67 times higher than those in B. tabaci). On the other hand, the B. tabaci population reared on cotton was more tolerant to all four insecticides tested than the T. vaporariorum population from the same host, especially to abamectin (up to 8.4-fold). The effects of the four host plants on the activity of carboxylesterase (CarE) in B. tabaci biotype B and T. vaporariorum were also compared. The results showed that, although the CarE activity of B. tabaci and T. vaporariorum varied depending on the host plants, the B. tabaci population possessed significantly higher CarE activity than the T. vaporariorum population reared on the same host plant. This was especially so on cucumber and cotton, where the CarE activities of the B. tabaci population were over 1.6 times higher than those of T. varporariorum. The frequency profiles for this activity in B. tabaci and T. vaporariorum populations reared on same host plant were apparently different.

On-column refolding and purification of transglutaminase from Streptomyces fradiae expressed as inclusion bodies in Escherichia coli.

Since transglutaminase (TGase) have been widely used in industry, mass production of the enzyme is especially necessary. The mature TGase gene from Streptomyces fradiae was cloned into pET21a and overexpressed in Escherichia coli BL21(DE3). The recombinant TGase was formed as inclusion bodies, and its content was as high as 55% of the total protein content. The insoluble fractions were separated from cellular debris by centrifugation and solubilized with 8 M urea. With an on-column refolding procedure based on cation SP Fast Flow chromatography with dual-gradient, the active TGase protein was recovered efficiently from inclusion bodies. The final purified product was 95% pure detected by SDS-PAGE. Under appropriate experimental conditions, the protein yield and specific activity of the TGase were up to 53% and 21 U/mg, respectively. Furthermore, the refolded recombinant protein demonstrated nearly identical ability to polymerized BSA compared with that of native TGase. One hundred and five milligrams of refolded TGase protein was obtained from 3.2g wet weight cells in the 400 ml cell culture.

[Purification and properties of manganese peroxidase from Trametes versicolor].

Two manganese peroxidase (MnP) active fractions D1 and D2 were got from the extracellular culture of Trametes versicolor by using ammonium sulfate precipitation, DEAE-cellulose DE52 chromatography. MnP1 was purified to electrophoretic homogeneity from the D2 by Phenyl Sepharose 6 Fast Flow chromatography and MnP2 was purified to electrophoretic homogeneity from the D1 by Sephacryl S-200HR chromatography and Phenyl Sepharose 6 Fast Flow chromatography. The specific activities of two MnP isozymes are 579.1U/mg and 425.0U/mg; purification folds are 17.51 and 12.85 and the yields are 6.17% and 2.47%, respectively. MnP1 and MnP2 have approximate molecular masses of 46.3kD and 43.0kD respectively, as determined by SDS-PAGE. The isoenzymes differed in optimum temperature (60degreesC and 65degreesC) and optimum pH(5.8 and 6.2) for oxidation of DMP (2,6-dimethoxyphenol). MnP1 and MnP2 are stable below 45degreesC and ranging from pH4.0 to pH7.0. DMP is the best substrate, the Km values of MnP1 and MnP2 for DMP are 13.43micromol/L and 12.45micromol/L respectively. Catalysis doesn't occur in the complete absence of Mn. EDTA inhibites the activities of MnP1 and MnP2 at the higher concentration and DTT inhibites the enzyme activities completely.

[Purification and properties of endoinulinase from Chaetomium sp].

An endoinulinase produced by Chaetomium sp. C34 was purified to electrophoretic homogeneity, with recovery of 7.7% activity and purification factor of 30.8 fold by five steps including ammonium sulfate precipitation, DEAE-cellulose, Q-sepharose Fast Flow, Sephacryl S-200 and Pre-Packed Hydrophobic Column. Its subunit molecular weight was estimated to be about 66kD by SDS-PAGE. The optimum temperature and pH of the enzyme activity were 50 approximately 55 degrees C and 6.0 respectively. The K(m) and V(max) values for inulin were 0.199 mmol/L and 115 micromol/(mg x min) respectively. Cu2+ completely inhibited inulinase activity. An appreciable loss of activity was observed in presence of NBS, Mn2+, Zn2+, Fe2+ and EDTA. A ratio of inulinase activity to invertase activity (I/S) of 20 was found in purified inulinase. The endoinulinase hydrolyzed inulin and liberated inulooligosaccharides. But it lacked activity toward melezitose or raffinose.