Quercetin and its derivatives for wound healing in rats/mice: Evidence from animal studies and insight into molecular mechanisms.

Aimed to clarify the effect of quercetin and its derivatives on wound healing in animal experiments. PubMed, Embase, Science Direct, Web of Science, SinoMed, Vip Journal Integration Platform, China National Knowledge Infrastructure and WanFang databases were searched for animal experiments investigating the effect of quercetin and its derivatives on wound healing to April 2023. The Review Manager 5.4 software was used to conduct meta-analysis. Eighteen studies were enrolled in this article. According to the SYRCLE's RoB tool assessment, these studies exposed relatively low methodological quality. It was shown that animals with cutaneous wound receiving quercetin had faster wound healing in wound closure (%) than the control group. Moreover, the difference in efficacy gradually emerged after third day (WMD = 7.13 [5.52, 8.74]), with a peak reached on the tenth day after wounding (WMD = 19.78 [17.82, 21.74]). Subgroup analysis revealed that quercetin for wound closure (%) was independent of the types of rats and mice, wound area and with or without diabetes. Clear conclusion was also shown regarding the external application of quercetin for wound healing (WMD = 17.77 [11.11, 24.43]). A significant reduction in the distribution of inflammatory cells occurred in the quercetin group. Quercetin could increase blood vessel density (WMD = 1.85 [0.68, -3.02]), fibroblast distribution and collagen fraction. Biochemical indicators, including IL-1ß, IL-10, TNF-α, TGF-ß, vascular endothelial growth factor (VEGF), hydroxyproline and alpha-smooth muscle actin (α-SMA), had the consistent results. Quercetin and its derivatives could promote the recovery of cutaneous wound in animals, through inhibiting inflammatory response and accelerating angiogenesis, proliferation of fibroblast and collagen deposition.

MicroRNA-98 regulates osteogenic differentiation of human bone mesenchymal stromal cells by targeting BMP2.

To study the effects of microRNA-98 (miR-98) on human bone mesenchymal stromal cells (hBMSCs). The patients undergoing hip arthroplasty were selected by inclusion/exclusion criteria for this study. The extracted hBMSCs were detected of osteogenic differentiation by alizarin red S staining, and of cell phenotype by flow cytometry. Bioinformatics, dual luciferase report, western blotting, RT-PCR and immunoblotting were used in our study. The hBMSCs were divided into miR-98 mimics, miR-98 negative control (NC), miR-98 inhibitors, Mock and miR-98 inhibitors + siBMP2 groups. Human bone mesenchymal stromal cells were extracted and purified in vitro and had specific cytological morphology, surface markers and abilities of self-renewal and differentiation. Compared with the NC group and Mock group, the miR-98 mimics group showed increased miR-98 level while the miR-98 inhibitors group decreased miR-98 level (both P < 0.01). Dual luciferase reporter showed BMP2 was the target gene of miR-98. The levels of mRNA and protein expression of BMP2, protein expression of RUNX2, alkaline phosphatase activity and osteocalcin content significantly decreased in the miR-98 mimics group while increased in the miR-98 inhibitors group and showed no changes in the NC group and Mock group (all P < 0.05). The miR-98 mimics group showed obviously declined stained red particles and the miR-98 inhibitors group showed opposite result. After lowering the expression of miR-98, osteogenic differentiation ability of hBMSCs rose, which was weakened by the transfection with siBMP2. miR-98 may regulate osteogenic differentiation of hBMSCs by targeting BMP2.

Land-use conversion and changing soil carbon stocks in China's 'Grain-for-Green' Program: a synthesis.

The establishment of either forest or grassland on degraded cropland has been proposed as an effective method for climate change mitigation because these land use types can increase soil carbon (C) stocks. This paper synthesized 135 recent publications (844 observations at 181 sites) focused on the conversion from cropland to grassland, shrubland or forest in China, better known as the 'Grain-for-Green' Program to determine which factors were driving changes to soil organic carbon (SOC). The results strongly indicate a positive impact of cropland conversion on soil C stocks. The temporal pattern for soil C stock changes in the 0-100 cm soil layer showed an initial decrease in soil C during the early stage (<5 years), and then an increase to net C gains (>5 years) coincident with vegetation restoration. The rates of soil C change were higher in the surface profile (0-20 cm) than in deeper soil (20-100 cm). Cropland converted to forest (arbor) had the additional benefit of a slower but more persistent C sequestration capacity than shrubland or grassland. Tree species played a significant role in determining the rate of change in soil C stocks (conifer < broadleaf, evergreen < deciduous forests). Restoration age was the main factor, not temperature and precipitation, affecting soil C stock change after cropland conversion with higher initial soil C stock sites having a negative effect on soil C accumulation. Soil C sequestration significantly increased with restoration age over the long-term, and therefore, the large scale of land-use change under the 'Grain-for-Green' Program will significantly increase China's C stocks.

Research progress and challenges in stem cell therapy for diabetic foot: Bibliometric analysis and perspectives.

BACKGROUND: Stem cell therapy has shown great potential for treating diabetic foot (DF). AIM: To conduct a bibliometric analysis of studies on the use of stem cell therapy for DF over the past two decades, with the aim of depicting the current global research landscape, identifying the most influential research hotspots, and providing insights for future research directions. METHODS: We searched the Web of Science Core Collection database for all relevant studies on the use of stem cell therapy in DF. Bibliometric analysis was carried out using CiteSpace, VOSviewer, and R (4.3.1) to identify the most notable studies. RESULTS: A search was conducted to identify publications related to the use of stem cells for DF treatment. A total of 542 articles published from 2000 to 2023 were identified. The United States had published the most papers on this subject. In this field, Iran's Shahid Beheshti University Medical Sciences demonstrated the highest productivity. Furthermore, Dr. Bayat from the same university has been an outstanding researcher in this field. Stem Cell Research & Therapy is the journal with the highest number of publications in this field. The main keywords were "diabetic foot ulcers," "wound healing," and "angiogenesis." CONCLUSION: This study systematically illustrated the advances in the use of stem cell therapy to treat DF over the past 23 years. Current research findings suggested that the hotspots in this field include stem cell dressings, exosomes, wound healing, and adipose-derived stem cells. Future research should also focus on the clinical translation of stem cell therapies for DF.

Investigating the effects of herbaceous root systems on the soil detachment process at the species level.

Plant root growth significantly affect soil detachment process, whereas the mechanism of how roots affect the soil detachment process by overland flow at species level is not fully understood. This study was conducted to investigate the soil detachment rate responds to plant-induce soil properties and root traits at species level. Two typical herbaceous plants, Bothriochloa ischcemum (Linn.). Keng (BI; fibrous root system) and Artemisia vestita Wall. ex Bess (AG; tap root system), from the Loess Plateau were studies for one year under six planted densities of 5 plants m-2, 10 plants m-2, 15 plants m-2, 20 plants m-2, 25 plants m-2, and 30 plants m-2. In total, 24 steel tanks were planted, and two plots were used as bare soil controls. Their soil detachment rates were tested under a constant overland flow (1.5 l s-1) on a 26.2 % slope. The results showed that soil detachment rate under the six planted densities ranged from 0.034 kg m2 s-1 to 0.112 kg m2 s-1 for BI and was ranged from 0.053 kg m2 s-1 to 0.132 kg m2 s-1 for AG, which all greatly reduced soil detachment rate and were 68.17 % to 92.33 % and 69.20 % to 87.27 % less than that of the control. In general, BI was more effective in reducing soil detachment rate than AG, achieving a mean soil detachment rate that was 23.75 % lower. With increasing plant density, soil detachment rate decreased as a power function. The overland flow hydraulic characteristics, soil properties and root traits influenced by plant density were positively or negatively correlated with soil detachment rate. Specifically, soil detachment rate decreased with velocity, bulk density, root length density, and increased with shear stress and Darcy-Weisbach friction factor as power or exponential functions. On this basis, the soil detachment rate (Dr) can be satisfactorily estimated by overland flow velocity (v), soil bulk density (BD) and root length density (RLD) as a power function (Dr = 63.03v0.174 × BD-20.712 × RLD-0.233R2 = 0.65; NSE = 0.60; p < 0.01).

Overexpression of RIN1 associates with tumor grade and progression in patients of bladder urothelial carcinoma.

Ras and Rab interactor 1 (RIN1) is an effector of H-Ras, which plays an important role in the development and progression of carcinomas, but it has not been reported in bladder cancer. Hence, the association of RIN1 expression with prognosis of bladder urothelial carcinoma (UC) was examined. RIN1 mRNA and protein expression in 20 paired UCs and the adjacent normal tissues was detected by quantitative reverse transcription polymerase chain reaction and Western blot. The expression of RIN1 protein in 96 specimens of UCs and 22 specimens of adjacent normal bladder tissues were analyzed by immunohistochemistry. The overall survival (OS) was assessed by univariate and multivariate analysis. Moreover, the progression-free survival (PFS) and recurrence-free survival (RFS), classified by the clinicopathologic features with RIN1 expression, were assessed by multivariate analysis. RIN1 mRNA and protein level was higher in UCs than in the adjacent normal tissues (P < 0.01). Enhanced RIN1 immunoexpression was associated with high histologic grades (P = 0.046), cancer progression (P = 0.047) as well as Ki-67 expression (P = 0.023). Furthermore, the 5-year survival rate was 29% in the subgroup with high level of RIN1 expression, while it was 43% in the subgroup with normal level of RIN1 expression (P < 0.05). Importantly, RIN1 level was revealed as the significant independent prognostic factor for death (P = 0.023) and progression (P = 0.003), but a weak contribution for recurrence (P = 0.063). Collectively, RIN1 expression could be a potential prognostic predictor for UC patients.

A novel 3D-printed patient-specific instrument based on "H-point" for medial opening wedge high tibial osteotomy: a cadaver study.

BACKGROUND: Opening wedge high tibial osteotomy (OWHTO) is an effective surgical treatment for knee osteoarthritis. This study aimed to explore the feasibility and accuracy of a novel 3D-printed patient-specific instrument (PSI) based on "H-point" for medial OWHTO in a prospective cadaver study. METHODS: Twenty-six fresh-frozen lower limbs were collected and randomly divided into two groups: PSI group treated with 3D virtual preoperative planning and a novel 3D-printed PSI; control group with the standard technique. 3D models were reversely reconstructed for preoperative surgical planning, guide plate design, and simulated osteotomy. Anatomic features of "H-point," surgical time, fluoroscopic dose, correction accuracy including tibiofemoral angle (FTA) and posterior tibial slope (TS) angle were measured. RESULTS: First, H-point was always described as a bony bulge in the posteromedial to the proximal tibia and had a relatively constant relationship with the osteotomy site. Second, the absolute correction error of mFTA and TS were significantly smaller in the PSI group. The effective rate of TS in the PSI group was more concentrated with absolute correction error within 1° and within 2° for 53.3% and 93.3%, compared to 9.1% and 45.5% in the control group. The total operation time, positioning osteotomy time, distraction correction time and fluoroscopy dose in the PSI group were significantly less than those in the control group. CONCLUSIONS: The novel 3D-printed PSI based on H-point is feasibility and accuracy with advantages in terms of TS, surgery time and radiation dose for OWHTO.

[Effects of Long-term Fertilization on Soil Nutrient Characteristics and Microbial Resource Restrictions in a Terrace on the Loess Plateau].

Long-term fertilization has an important effect on soil fertility and soil microbial activity. In order to explore the effects of long-term fertilization on soil extracellular enzyme activities and nutrient characteristics in a terrace on the Loess Plateau, we based our investigation on the long-term nutrient localization plot of Ansai Soil and Water Conservation Experimental Station, Chinese Academy of Sciences. We measured the soil physicochemical properties, microbial biomass, and extracellular enzyme activities of six fertilization treatments, which included no fertilization (CK); manure and nitrogen fertilization (MN); manure and phosphate fertilization (MP); manure, nitrogen, and phosphate fertilization (MNP); manure (M); and nitrogen and phosphate fertilization (NP). The results showed that all fertilization treatments significantly increased soil nutrient content and soil extracellular enzyme activities compared with that in CK. Correlation analysis showed that extracellular enzyme activity and soil physicochemical properties had an extremely significant correlation. The redundancy analysis indicated that soil nutrient and soil microbial biomass could explain 79.66% and 74.87% of the variation in soil extracellular enzyme activity and its stoichiometric ratio, respectively. Thus, the effects of fertilization on soil fertility were primarily through influencing soil extracellular enzyme activities indirectly. M, MN, MP, and MNP significantly improved soil organic carbon (SOC); soil total nitrogen (STN); and carbon (C), nitrogen (N), and phosphorus (P) source enzyme content; however, MNP changed the soil pH, which had an inhibitory effect on microbial activities. Vector analysis showed that the microbial communities of all treatments were in the condition of P limitation. Although MNP could alleviate the extent of P limitation, there was no significant difference between M and MP. Our study indicated that long-term application of manure[7500 kg·(hm2·a)-1]could meet the nutrient requirements of dryland crop growth, and long-term application of manure combined with phosphorus fertilization could alleviate the resource constraints faced by microorganisms. Consequently, our results provide a new insight into improving regional nitrogen excess.

Effects of root morphological traits on soil detachment for ten herbaceous species in the Loess Plateau.

Plant root systems can greatly reduce soil loss, and their effects on soil erosion differ across species due to their varied root traits. The purpose of this study was to determine the effects of root morphology traits of herbaceous plants on the soil detachment process. Ten herbaceous plants (dominant species) in the Loess Plateau were selected, and 300 undisturbed soil samples (including living roots from the selected herbages) were scoured with flowing water to measure their soil detachment capacities under six levels of shear stress (4.98 to 16.37 Pa). Then, the root traits of each soil sample were measured, and the rill erodibility and critical shear stress were estimated based on the Water Erosion Prediction Project (WEPP) model. The results showed that root morphology traits varied greatly among the ten selected herbages. Accordingly, resulting variations in soil detachment capacity (0.030 to 3.297 kg m-2 s-1), rill erodibility (0.004 to 0.447 s m-1), and critical shear stress (4.73 to 1.13 Pa) were also observed. Plants with fibrous roots were more effective than those with tap roots in reducing soil detachment. Their mean soil detachment capacity and rill erodibility were 93.2% and 93.4% lower, respectively, and their mean critical shear stress was 1.15 times greater than that of the herbaceous plants with tap root systems. Of all the root traits, root surface area density (RSAD) was the primary root trait affecting the soil detachment, and it estimated the soil detachment capacity well (R2 = 0.91, normalized squared error (NSE) = 0.82). Additionally, an equation with few factors (soil aggregate and RSAD) was suggested to simulate the soil detachment capacity when the plant root parameters and soil properties were limited.

[Effect of restoration types on the community structure of microbes harboring nifH and chiA genes in alpine meadow]. / 不同恢复方式对退化高寒草甸土壤nifH和chiA微生物群落结构的影响.

Biological nitrogen (N) fixation and organic N degradation are the main sources of soil available N, while microorganisms driving such processes play an important role in soil N supply and the maintenance of soil fertility. In this study, real-time quantitative PCR and amplicon sequencing technology were used to examine the effects of restoration types on the community structure of N2-fixing and chitin-degrading bacteria harboring nifH and chiA genes, respectively, and the gene abundance under four meadows (undisturbed, grazing, fencing, and fencing + reseeding mea-dows) in Qinghai-Tibet Plateau. The results showed that the abundance of nifH and chiA in the four meadows followed the order of undisturbed meadow > grazed meadow > fencing meadow > fencing + reseeding meadow. The abundance of nifH and chiA in the undisturbed meadow was 3.4-6.3 times and 3.3-8.3 times of that in the other three meadows. The α diversity of N2-fixing bacteria in gra-zing, fencing, and fencing + reseeding meadows was significantly higher than that in the undisturbed meadow, while the α diversity of chitin-degrading bacteria was higher in the undisturbed and grazing meadows. Grazing significantly increased the relative abundance of Proteobacteria, but decreased the relative abundance of Cyanobacteria and Actinobacteria. The abundance of nifH and chiA was significantly affected by soil moisture, nutrients, and vegetation characteristics, while the community structure of nifH and chiA was affected by soil moisture, soil organic carbon content, and soil pH. Compared with undisturbed meadow, grazing reduced the potential of N fixation and organic N degradation.The improvement of 10 years grazing prohibition with fencing and reseeding measures on the function of N fixation and organic N degradation was not obvious. The characteristics of functional microbes and their influencing factors should be comprehensively considered during meadow restoration, which might take longer time or take reasonable management measures to restore grazing meadow to undisturbed level.

Atlas of Human Skeleton Hardness Obtained Using the Micro-indentation Technique.

OBJECTIVES: Measure and systematically evaluate the distribution of microhardness in the human skeleton. METHODS: Three fresh corpses were obtained, aged 62 (male), 45 (female), and 58 years (male). Soft tissues were removed, and all axial and unilateral appendicular bones were freshly harvested. All three skeletons were examined by X-ray and computed tomography (CT) to exclude skeletal pathology. Only bones from donors with no known skeletal pathology were included in the study. Axial and unilateral appendicular skeleton bones from each of the three donors were obtained, except for ear ossicles, hyoid bone, tailbone, and 14 phalanges of the foot, for which samples were difficult to obtain. Precision bone specimens with a thickness of 3 mm, which were cut with a Buehler IsoMet 11-1280-250 low-speed diamond saw (Buehler, USA), were obtained from all important anatomic sites in a direction perpendicular to the mechanical axis of each bone. Micro-indentation (the Vickers hardness test) was performed on the surface of each specimen using a microhardness tester with a diamond indenter. Hardness value (HV) was computed for each indentation. Each bone specimen was divided into several regions of interest. Indentations were carefully made and computed. Then we analyzed the data to identify hardness distribution rules at different anatomic sites. RESULTS: In total, 5360 indentations were made in 1072 regions of interest in each donor. Hardness of the axial and appendicular bones were all inhomogeneous depending on the anatomic sites, but the distribution of microhardness followed certain rules. The mean hardness value ranged from 24.46 HV (HV = hardness value, kgf/mm2 ) for the sacrum to 53.20 HV for the shaft of the tibia. The diaphysis was harder than the metaphysis, and the proximal and distal epiphysis had lower values (8.85%- 40.39%) than the diaphysis. Among the long bone diaphyses, the tibia cortical bone (51.20 HV) was the hardest, harder than the humerus (47.25 HV), the ulna (43.26 HV), the radius (42.54 HV), and the femur (47.53 HV). However, in some anatomic sites such as the lumbar vertebra (cortical bone 32.86 HV, cancellous bone 31.25 HV), the cortical shells were sometimes not harder than the internal cancellous bones. The lumbar vertebra (32.86 HV) was harder than the cervical vertebra (28.51 HV) and the thoracic vertebra (29.01 HV). CONCLUSIONS: The distribution of microhardness in the human skeleton follows certain rules. These distribution rules could be used to predict the mechanical properties of bone and progress in this field could provide data for the basis of a new three-dimensional printing technique, which may lead to new perspectives for custom-made implants.

[Construction and application of a new index for quantifying root erosion resistance: Root framework erosion resistance index]. / ä¸€ç§é‡åŒ–æ ¹ç³»æŠ—ä¾µèš€æŒ‡æ ‡çš„æž„å»ºåŠåº”ç”¨:æ ¹ç³»æž„æž¶æŠ—èš€æŒ‡æ•°.

The matching of root system is a key factor driving the resistance of plant community to soil erosion. In this study, Amoeba graphical method was used to establish a root framework erosion resistance index (ERIrf, %) from three dimensions of root morphology, quantity and spatial concerns to quantify the effective of root erosion resistance by plant community. We analyzed root growth characteristics of plant community from abandoned land, Caragana korshinskii and Robinia pseudoacacia communities in loess hilly area. The results showed that the parameters of constructing the root framework erosion resistance index included the acting coefficient of root framework (α), root density (Rb, kg·m-3), root framework degree (S), soil bulk density (ρ, g·cm-3), and soil and water conservation coefficient (φ). The equation could be expressed as ERIrf=α×Rd×S×φρ×100%. This root framework erosion resistance index well represented the erosion resistance effects of plant root system. Logarithmic function could better fit the relationship between soil erosion resis-tance ability and root framework erosion resistance index. Our findings would provide scientific reference for the construction of anti-erosion vegetation community and assessment of ecological construction.

[Kinetic parameters and temperature sensitivity of soil nitrogen and phosphorus transforming enzymes in Robinia pseudoacacia plantations under different vegetation zones on the Loess Plateau, China]. / é»„åœŸé«˜åŽŸä¸åŒæ¤è¢«å¸¦äººå·¥åˆºæ§æž—åœŸå£¤æ°®ç£·è½¬åŒ–é ¶åŠ¨åŠ›å­¦å‚æ•°åŠå ¶æ¸©åº¦æ•æ„Ÿæ€§.

Soil enzymes are catalysts for organic matter decomposition, the kinetic characteristics of which are important indicators of the catalytic performance of enzymes, with important role in evalua-ting soil health quality. We examined the responses of soil enzyme kinetic parameters to temperature change and the variation characteristics of their temperature sensitivity (Q10) in Robinia pseu-doacacia plantation soil under three different vegetation zones on the Loess Plateau. The results showed that the potential maximum reaction rate (Vmax) and the half-saturation constant (Km) of alanine transaminase (ALT), leucine aminopeptidase (LAP) and alkaline phosphatase (ALP) all increased linearly with the increasing incubation temperature. The zonal regularity of forest zone > forest-steppe zone > steppe zone was presented in Vmax. The temperature sensitivity of Vmax(Q10(Vmax)) ranged from 1.14 to 1.62, and the temperature sensitivity of Km(Q10(Km)) ranged from 1.05 to 1.47, with both values being lower in forest-steppe zone than other vegetation zones. In low and high temperature regions, the variations of Q10 in different soil enzymes differed among vegetation zones. Results from redundancy analysis showed that Q10 had a significant correlation with environmental variables, especially soil nutrients, indicating that Q10 would be affected by other environmental factors besides temperature.

Effects of soil-incorporated plant litter morphological characteristics on the soil detachment process in grassland on the Loess Plateau of China.

The Loess Plateau of China is one of the most eroded areas in the world. In the past 20 years, effective vegetation restoration measures have significantly changed the near-surface characteristics of soil. In natural conditions, plant litter is widespread in the topsoil. The effects of litter incorporated into soil on the process of soil detachment, which is closely related to plant litter morphology, are still not well known. This study aimed to detect the variation of litter morphological characteristics and quantify their effects on soil detachment capacity and rill erodibility when litter is incorporated into the soil. Four plant litters (Bothriochloa ischaemum (L.) Keng., Artemisia sacrorum Ledeb., Setaria viridis (L.) Beauv., and Artemisia capillaris Thunb.) with five length levels (<0.5, 0.5-2, 2-4, 4-6, and 6-8 cm) were incorporated into soil (idle for 50 days) at the same litter biomass rate (0.7 kg m-2). Then the soil was sampled and cores were subjected to overland flow under six flow shear stress levels (5.66, 8.31, 12.21, 15.55, 19.15 and, 22.11 Pa) using a hydraulic flume (4.0 m × 0.35 m). The results showed that the litter morphological characteristics of litter length density (LLD), litter surface area density (LSAD) and litter volume ratio (LVR) differed in plant species at the same litter biomass rate. Correspondingly, soil detachment capacity (ranging from 0.414 to 2.179 kg m-2 s-1) and rill erodibility (ranging from 0.037 to 0.177 s m-1) varied significantly and mean values from the Bothriochloa ischaemum (L.) Keng. treatments were the minimums, which were 28% to 37% and 23% to 35% less than that of the other treatments, respectively. The soil detachment capacity and rill erodibility were significantly correlated with the litter morphological characteristics of LLD, LSAD and LVR (p < 0.01). The contact area between litter and soil was the most critical factor affecting soil detachment. Incorporated plant litter residue litter effect on rill erodibility could be well estimated by LSAD.

[Effects of grazing exclusion on the abundance of functional genes involved in soil nitrogen cycling and nitrogen storage in semiarid grassland]. / ç¦ç‰§å¯¹åŠå¹²æ—±è‰åœ°åœŸå£¤æ°®å¾ªçŽ¯åŠŸèƒ½åŸºå› ä¸°åº¦å’Œæ°®å‚¨é‡çš„å½±å“.

We investigated the effects of grazing exclusion on the abundance of functional genes (nifH, amoA-AOA, amoA-AOB, narG, nirK, nirS, and nosZ) involved in soil nitrogen cycling in soil profiles (0-10, 10-20, 20-40 and 40-60 cm) from a chronosequence of grazing exclusion (0, 7, 18, 27 and 35 years) in the semiarid grasslands of the Loess Plateau. The relationship between abundance of functional genes and soil nitrogen storage was evaluated. The results showed that 35 years exclusion increased the abundance of nifH and amoA-AOB genes by 67.8% and 17.6% compared with the grazed grassland, respectively, and decreased that of nirK genes. The abundance of nifH, narG, and nirS genes in surface soil (0-10 cm) were significantly higher than that in deep soil (20-40 and 40-60 cm), indicating that those genes had surface accumulation effects. Grazing exclusion increased soil nitrogen storage. Soil nitrogen storage in 0-60 cm layer was the highest at 27 years (20.96 mg·hm-2), indicating that 27 years might be the optimum for grazing exclusion. The abundance of nifH, amoA-AOA and amoA-AOB had a significant linear relationship with nitrogen storage, suggesting that microbes harboring these genes played an important role in soil nitrogen accumulation. Total nitrogen, bulk density, and available phosphorus content were the dominant factors affecting the abundance of functional genes involved in soil nitrogen cycling. Our results provided a scientific reference for understanding soil nitrogen cycling and restoration of degraded grassland.

Bone Hardness of Different Anatomical Regions of Human Radius and its Impact on the Pullout Strength of Screws.

OBJECTIVE: To investigate the bone hardness of different anatomical regions of the human radius and its impact on the pullout strength of screws. METHODS: Fresh radius bones were obtained from three donated cadavers. They were divided into three parts: proximal metaphysis, shaft, and distal metaphysis. The proximal metaphysis contains the head, neck, and radial tuberosity. The distal metaphysis includes the palmaris radius and the styloid process. The shaft of the radius was divided into nine segments of equal length. The bone hardness of three radiuses, one from each cadaver, was measured by Vickers microindentation hardness tests, and the screw pullout strength was examined in the other three radiuses using a materials testing machine. The trend between radius hardness and pullout strength was analyzed by using an analysis of variance randomized block design. Pearson correlation analysis was performed to evaluate the linear correlation between the bone hardness and the pullout strength of the human radius. RESULTS: The mean hardness ranged from 33.30 HV (the head) to 43.82 HV (the diaphysis). The hardest part of the radius was the shaft, with a value of 42.54 ± 5.59 HV. The proximal metaphysis had a hardness value of 34.15 ± 6.48 HV, and the distal metaphysis hardness value was 35.24 ± 5.17 HV. The shaft was 23.5% harder than the proximal metaphysis and 20% harder than the distal metaphysis. The microhardness test demonstrated that the bone hardness value of the diaphysis was significantly higher than those of both the proximal and distal metaphysis of the radius (both P < 0.05). The mean pullout strength values ranged from 552 N (the distal metaphysis) to 2296 N (the diaphysis). The greatest pullout strength of the radius was observed for the shaft, with a pullout strength of 1727.96 ± 111.44 N. The pullout strength of the proximal metaphysis was 726.33 ± 236.39 N, and the pullout strength of the distal metaphysis was 590.67 ± 36.30 N. The pullout strength of the shaft was 138% greater than that of the proximal metaphysis and 190% greater than that of the distal metaphysis. The pullout strength was also higher in the diaphysis than at both ends of the radius (both P < 0.05). A positive correlation was found between bone hardness and pullout strength (R = 0.927, P < 0.001). CONCLUSIONS: Bone hardness and screw pullout strength are higher in the diaphysis of the radius than at either end. The pullout strength is positively related to bone hardness in the human radius.

[Expression of cyclooxygenase-2 in bladder transitional cell carcinoma and the significance thereof].

OBJECTIVE: To study the expression of cyclooxygenase-2 (COX-2) in bladder transitional cell carcinoma (Tcc) and the clinical significance thereof. METHODS: Immunohistochemistry was used to detect the expression of COX-2 in 56 specimens of bladder Tcc and 10 specimens of normal bladder tissue, all resected during operation. RESULTS: No expression of COX-2 was detected in the 10 specimens of normal bladder tissue and in the 56 specimens of bladder Tcc the positive rate of COX-2 was 55.36%. The expression of COX-2 in bladder Tcc was closely correlated with the grade and stage of tumor (both P < 0.01). CONCLUSION: COX-2 expression in bladder Tcc is closely correlated with the grade and stage.

[Realization and investigation of relative experimental parameter of coherent population trapping frequency standard].

It is desirable for an atomic frequency standard that clock transition signal is of both high S/N rate and narrow linewidth. While for a passive coherent population trapping (CPT) frequency standard, increasing S/N rate is at the expense of enwidened lidnewidth, therefore it is crucial to choose a proper combination of S/N rate and linewidth. The present paper presents the experimental results of our systematically study on the relations between clock transition signal and parameters such as temperature and laser intensity with an optical table top CPT frequency standard. The obtained results provide us the criterion of choosing the combination of S/N rate and lidnewidth. The paper also presents experimental study results of de-coherent effect caused by unperfect circular polarization laser. Those experimental results were the good reference in the realization of CPT frequency standard, and they are also the general reference to CPT phenomenon and CPT frequency standard studies.

Ru-catalyzed dehydrogenative coupling of carboxylic acids and silanes--a new method for the preparation of silyl ester.

Ru(3)(CO)(12)/EtI has been found to be an efficient catalyst system for the dehydrosilylation of carboxylic acids with silanes. In the presence of 1 mol% Ru(3)(CO)(12) and 4 mol% EtI, dehydrosilylation reactions in toluene afforded the corresponding silyl esters at 100 degrees C in good and high yields.

[Effects of nitrogen addition and elevated CO2 concentration on soil dissolved organic carbon and nitrogen in rhizosphere and non-rhizosphere of Bothriochloa ischaemum]. / æ°®ç´ æ·»åŠ å’ŒCO2æµ“åº¦å‡é«˜å¯¹ç™½ç¾Šè‰æ ¹é™ å’Œéžæ ¹é™ åœŸå£¤æ°´æº¶æ€§æœ‰æœºç¢³ã€æ°®çš„å½±å“.

A pot experiment was conducted to study soil dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in the rhizosphere and non-rhizosphere of Bothriochloa ischaemum in loess hilly-gully region under the different treatments of CO2 concentrations (400 and 800 µmol·mol-1) and nitrogen addition (0, 2.5, 5.0 g N·m-2·a-1). The results showed that eleva-ted CO2 treatments had no significant effect on the contents of DOC, dissolved total nitrogen (DTN), DON, dissolved ammonium nitrogen (NH4+-N) and dissolved nitrate nitrogen (NO3--N) in the soil of rhizosphere and non-rhizosphere of B. ischaemum. The contents of DTN, DON, and NO3--N in the rhizosphere soil were significantly increased with the nitrogen application and the similar results of DTN and NO3--N also were observed in the non-rhizosphere of B. ischaemum. Nitrogen application significantly decreased DOC/DON in the rhizosphere of B. ischaemum. The contents of DTN, NO3--N and DON in the soil of rhizosphere were significantly lower than that in the non-rhizosphere soil, and DOC/DON was significantly higher in the rhizosphere soil than that in the non-rhizosphere soil. It indicated that short-term elevated CO2 concentration had no significant influence on the contents of soil dissolved organic carbon and nitrogen. Simulated nitrogen deposition, to some extent, increased the content of soil dissolved nitrogen, but it was still insufficient to meet the demand of dissolved nitrogen for plant growing.