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Experimental studies were conducted in a super-large wave flume, aiming at uncovering the hydrodynamic characteristics involved in the turbulent wave boundary layer of full scale environment. An explicit formula of boundary layer thickness on rough turbulent flow was presented based on the measured velocity data of the present study and collected experimental data on wave boundary layer. It was found that the bottom wave-associated nominal stresses under the conditions of prototype scale tests suppress the vertical turbulence scattering upward over the boundary layer, which accounts for thickening of the boundary layer under wave condition. Such effect has yet not been reported in the literatures using oscillatory U-tube or small-sized wave flume. The phase inconsistency in the turbulent boundary layer to the free stream velocity (velocity immediately outside the boundary layer) is within 15°, which is remarkably smaller than the results from oscillatory U-tubes, as well as the larger wave flume experiment presented by Xie et al. (2021), showing that the coarser bed would further reduce the phase lead. The intensity of the vertical turbulent component is approximately 1/2 of the horizontal component, which has larger ratio compared with the value of 1/5 reported by previous studies. Especially, it was also found that the vertical turbulent energy was approximately 3/4 of the turbulent energy in spanwise directions (y-direction). This means that the turbulent fluctuation has similar order in all three-directions (x, y, z) in a full scale environment and highlights that the turbulent components in all the three directions should not be neglected when calculating the total turbulent energy.

The value of the high-resolution data lies in the high-precision information discovery. The fine-detailed landform element extraction is thus the basis of high-fidelity application of the high-resolution digital elevation models (DEMs). However, the results of landform element extraction generated by classical methods might be ungrounded on high-resolution DEMs. This paper presents our research on using the aspect to reinforce the applicability and robustness of the classical approaches in landform element extraction. First, according to the research of pattern recognition, we assume that aspect-enhanced landform representation is robust to rotation, scaling and affine variance. To testify the role of aspect, we respectively integrated the aspect into three classical approaches: mean curvature-based fuzzy classification, elevation-based feature descriptor, and object-based segmentation. In the experiment, based on four types of high-resolution DEMs (1 m, 2 m, 4 m and 8 m), we compare each classical approaches and their corresponding aspect-enhanced approaches based on extracting the rims of two craters having different landforms, and the ridgelines and valleylines of a region covered by few vegetables and man-made buildings. In comparison to the results generated by curvature-based fuzzy classification, the aspect enhanced curvature-based fuzzy classification can effectively filter a number of noises outperforms the curvature-based one. Otherwise, the aspect-enhanced feature descriptor can detect more landform elements than the elevation-based feature descriptor. Moreover, the aspect-based segmentation can detect the main structure of landform, while the boundaries segmented by classical approaches are messing and meaningless. The systematic experiments on meter-level resolution DEMs proved that the aspect in topography could effectively to improve the classical method-system, including fuzzy-based classification, feature descriptors-based detection and object-based segmentation. The value of aspect is significantly great to be worthy of attentions in landform representation.

Objective To obtain the elastic quantitative and semi-quantitative indexes of solid breast masses using ultrasound linear array probes with two different frequencies, and to construct prediction models and evaluate their diagnostic values. Methods A total of 92 patients who were scheduled for surgical treatment on solid breast masses were enrolled in this study. Linear array probes with two frequencies, 9-3 MHz (L9 group) and 14-5 MHz (L14 group), were used for sound touch elastography and strain elastography before surgery, and the maximum elasticity value (Emax), average elasticity value (Emean), minimum elasticity value (Emin), standard deviation (SD)(in kPa), elasticity ratio (E), and strain ratio to fat (SRf) were recorded and calculated for the breast mass (A) and surrounding tissues (Shell). The elastic characteristic indexes of the L9 group and L14 group were compared, and the prediction models of these two groups were constructed using Logistic regression method. Results The diagnostic performance of the prediction model based on L9 group was better than the model based on L14 group (AUC: 0.904 vs. 0.810, P = 0.0343, z = 2.116) and the best single index EMax-shell-L9 (P = 0.0398, z = 2.056). The sensitivity of L9 based model was 85.19% and the specificity was 84.21%. Conclusion The prediction model based on quantitative and semi-quantitative elastic ultrasound indexes from L9-3 probe exhibited better performance, which could improve the diagnostic accuracy for malignant breast tumors.

Pinus bungeana is one of indigenous trees in China and widely distributed in poor and arid regions for vegetation and industrial woody use. However, since a high-incidence disease threatens the growth of mature P. bungeana tree in the garden and in the plantation every year, the overwintering shoots were infected and died in the next spring with a ratio over 70%, but the cause was beyond understood. A total of 120 fungal isolates were separated from symptomatic twigs by histological isolation methods, including Pestalotiopsis spp., Fusarium spp., Trichothecium spp., Penicillium and some unknown fungal species. Pestalotiopsis spp. was dominant, accounting for 85%. Morphological observation under microcopy showed all Pestalotiopsis species are identical, and six isolations among them were randomly selected for pathogenicity tests. Fulfilling Koch's postulates showed that all six isolates of Pestalotiopsis spp. were pathogens of twig blight, causing the same symptoms as observed in the field, while other non-Pestalotiopsis isolates were avirulent to P. bungeana twigs. Multi-gene (ITS, tub2 and TEF1) analysis and morphological observation revealed that all the six Pestalotiopsis isolates belonged to P. trachicarpicola. To our knowledge, this is the first study reporting P. trachicarpicola as the pathogens responsible for P. bungeana twig blight in China.

It is urgent to identify and validate biomarkers for early diagnosis and efficient treatment of nasopharyngeal carcinoma (NPC). Recent studies have proposed p38 gamma (p38γ) as a cyclin-dependent kinase (CDK)-like kinase that phosphorylates retinoblastoma (Rb) to promote cyclins expression and tumorigenesis. Here the Gene Expression Profiling Interactive Analysis (GEPIA) database and results from the local NPC tissues demonstrate that p38γ is significantly upregulated in NPC tissues, correlating with poor overall survival. Furthermore, p38γ mRNA and protein expression is elevated in established NPC cell lines (CNE-1 HONE-1 and CNE-2) and primary human NPC cells, but low expression detected in human nasal epithelial cells. In established and primary NPC cells, p38γ depletion, using the shRNA strategy or the CRISPR/Cas9 gene-editing method, largely inhibited cell growth, proliferation and migration, and induced significant apoptosis activation. Contrarily, ectopic p38γ overexpression exerted opposite activity and promoted NPC cell proliferation and migration. Retinoblastoma (Rb) phosphorylation and cyclin E1/A expression were decreased in NPC cells with p38γ silencing or knockout, but increased after p38γ overexpression. Moreover, mitochondrial subcellular p38γ localization was detected in NPC cells. Significantly, p38γ depletion disrupted mitochondrial functions, causing mitochondrial depolarization, reactive oxygen species production, oxidative injury and ATP depletion in NPC cells. In vivo, intratumoral injection of adeno-associated virus-packed p38γ shRNA potently inhibited primary human NPC xenograft growth in nude mice. In p38γ shRNA virus-injected NPC xenograft tissues, p38γ expression, Rb phosphorylation, cyclin E1/A expression and ATP levels were dramatically decreased. Taken together, we conclude that p38γ overexpression is required for NPC cell growth, acting as a promising therapeutic target of NPC.

The PKCε-regulated genome protective pathway provides transformed cells a failsafe to successfully complete mitosis. Despite the necessary role for Aurora B in this programme, it is unclear whether its requirement is sufficient or if other PKCε cell cycle targets are involved. To address this, we developed a trapping strategy using UV-photocrosslinkable amino acids encoded in the PKCε kinase domain. The validation of the mRNA binding protein SERBP1 as a PKCε substrate revealed a series of mitotic events controlled by the catalytic form of PKCε. PKCε represses protein translation, altering SERBP1 binding to the 40 S ribosomal subunit and promoting the assembly of ribonucleoprotein granules containing SERBP1, termed M-bodies. Independent of Aurora B, SERBP1 is shown to be necessary for chromosome segregation and successful cell division, correlating with M-body formation. This requirement for SERBP1 demonstrates that Aurora B acts in concert with translational regulation in the PKCε-controlled pathway exerting genome protection., PKCε is known to exert a role in genome protection by directly phosphorylating and switching the specificity of Aurora B. Here the authors identify SERBP1 as a parallel mitotic PKCε substrate controlling translation and ensuring the integrity of chromosome segregation and successful cell division.

Presented herein is a study on the ignition reaction kinetics and mechanism of B4C/KNO3 and B4C/KClO4 pyrotechnic smoke compositions using the non-isothermal thermogravimetry and differential scanning calorimetry techniques. The pyrotechnics in oxygen balance of − 10%, − 20% and − 30% were prepared for the experiments. The results of measurements showed that the pyrotechnics in oxygen balance of − 20% had the highest enthalpy. The activation energy (Ea) of ignition reactions was calculated by using Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS) methods. The Ea values of B4C/KNO3 and B4C/KClO4 were 139.5 and 214.6 kJ mol−1 calculated by OFW method, and 129.3 and 210.7 kJ mol−1 by KAS method. The differential and integral reaction mechanism functions of B4C/KNO3 and B4C/KClO4 were determined, respectively, by z(α) master plots method, f1(α) = 2(1 − α)[− ln(1 − α)]1/2, g1(α) = [− ln(1 − α)]1/2, and f2(α) = 3(1 − α)[− ln(1 − α)]2/3, g2(α) = [− ln(1 − α)]1/3. The pre-exponential factors, lnA = 11.6 and 22.3 min−1, were obtained by the intercept of KAS method for ignition reaction of B4C/KNO3 and B4C/KClO4 pyrotechnics. Based on the results, the burning rates, thermal sensitivities and application methods of B4C/KNO3 and B4C/KClO4 were predicted.

Chinese summer extreme rainfall often brings huge economic losses, so the prediction of summer extreme rainfall is necessary. This study focuses on the predictability of the leading mode of Chinese summer extreme rainfall from empirical orthogonal function (EOF) analysis. The predictors used in this study are Arctic sea ice concentration (ASIC) and regional sea surface temperature (SST) in selected optimal time periods. The most important role that Arctic sea ice (ASI) plays in the appearance of EOF1 may be strengthening the high pressure over North China, thereby preventing water vapor from going north. The contribution of SST is mainly at low latitudes and characterized by a significant cyclone anomaly over South China. The forecast models using predictor ASIC (PA), SST (PS), and the two together (PAS) are established by using data from 1980 to 2004. An independent forecast is made for the last 11 years (2005–2015). The correlation coefficient (COR) skills between the observed and cross-validation reforecast principal components (PC) of the PA, PS, and PAS models are 0.47, 0.66, and 0.76, respectively. These values indicate that SST is a major cause of Chinese summer extreme rainfall during 1980–2004. The COR skill of the PA model during the independent forecast period of 2004–2015 is 0.7, which is significantly higher than those of the PS and PAS models. Thus, the main factor influencing Chinese summer extreme rainfall in recent years has changed from low latitudes to high latitudes. The impact of ASI on Chinese summer extreme rainfall is becoming increasingly significant.

BackgroundConsidering that current peritoneal dialysis has its own shortcomings, In this study, the Seldinger technique was modified to explore the relationship between different catheter placement methods of peritoneal dialysis and short-term postoperative complications.MethodsWe retrospectively analyzed the data of 157 patients who received peritoneal dialysis in the Department of Nephrology of our hospital from January 2017 to December 2019. According to different catheter placement methods, the patients were divided into three groups: 111 cases of open surgery technique, 23 cases of Seldinger technique, and 23 cases of modified Seldinger technique (ultrasound-guided Veress needle puncture). The general data, laboratory indexes, and abdominal infection and catheter-related complications within one month postoperatively were collected.ResultsThere were 48 (31.0 %) cases of complications in 157 patients within one month postoperatively, which were mainly catheter-related complications (45 cases, 29.0 %). The incidence of catheter tip peritoneal drift (catheter migration) in the three groups was 27.3 %, 39.1 %, and 9.1 %, respectively, with no significant difference between groups (P = 0.069). Univariate logistic regression analysis showed that the systolic blood pressure, history of abdominal and pelvic surgery, creatinine, and modified Seldinger technique were possible impact factors of catheter migration (P P = 0.045); However, the difference between the Seldinger method group and the open surgery group was not significant, with an OR of 1.061 (95 % confidence interval: 0.308–3.649,P = 0.926). Curve fitting showed that the average incidence of catheter migration in the three groups was 27.3 % (95% CI: 15.9-42.7 %), 28.5 % (95% CI: 10.7-56.9 %), and 5.7 % (95% CI: 1.0-27.0 %); the modified Seldinger method has the lowest average incidence of catheter migration.ConclusionsModified Seldinger technique can significantly reduce catheter-related short-term complications after peritoneal dialysis, and it is especially effective in reducing the incidence of catheter migration. Modified Seldinger technique is a safe and feasible method for the placement of a peritoneal dialysis catheter.

Gap exists in the interface of cement asphalt emulsion mortar and CRTS I track slab universally, which is more severe at four corners than other parts of the track slab. In this work, the temperature and elevation of CRTS I slab track with and without rail were measured continuously to study the influence mechanism of rail on the gap. The results show that the alternating temperature gradient of track slab is the main reason that causes the gap, and laying rail can efficiently decrease the gap size in the slab track without rail. Compared with the slab track without rail, the maximum elevation occurred at the corner, the maximum gap width and the maximum gap depth of the slab track with rail laid were decreased by 0.45 mm (25.7%), 0.75 mm (46.6%) and 9.5 mm (59.4%), respectively; meanwhile, the disqualification ratio at corners was reduced to 5.9%, which is 50% less than that of the track without rail. When elevation mismatch occurs in adjacent track slabs, a gasket should be placed at rail-bearing bed below the track slab in order to avoid the lower slab being dragged up by the higher slab and the further occurrence of new gap.

CH4 emissions could vary with biotic and abiotic factors at different time scales. However, little is known about temporal dynamics of CH4 flux and its controls in coastal marshes. In this study, CH4 flux was continuously measured with the eddy covariance technique for 2 years in a subtropical salt marsh in eastern China. Wavelet analysis was applied to explore the multi-scale variations of CH4 flux and its controls. Additionally, partial wavelet coherence was used to disentangle confounding effects of measured variables. No consistent diurnal pattern was found in CH4 fluxes. However, the hot-moments of CH4 flux were observed after nighttime high tide on days near the spring tide. Periodic dynamics were also observed at multi-day, semilunar and seasonal scales. Tide height in summer had a negative effect on CH4 flux at the semilunar scale. Air temperature explained most variations in CH4 fluxes at the multi-day scale but CH4 flux was mainly controlled by PAR and GEP at the seasonal scale. Air temperature explained 48% and 56% of annual variations in CH4 fluxes in 2011 and 2012, respectively. In total, the salt marsh acted as a CH4 source (17.6 ± 3.0 g C–CH4 m−2 year−1), which was higher than most studies report for inland wetlands. Our results show that CH4 fluxes exhibit multiple periodicities and its controls vary with time scale; moreover, CH4 flux is strongly modified by tide. This study emphasizes the importance of ecosystem-specific measurements of CH4 fluxes, and more work is needed to estimate regional CH4 budgets.

Compressed sensing changes the conventional image processing model of full collection-sampling-compression-transmission-reconstruction and provides a more feasible way to the UAV wireless transmission. Existing matching pursuit algorithms cannot simultaneously meet the requirements of reconstruction accuracy and reconstruction efficiency in UAV wireless transmission, especially when the images are polluted by some noise. Hence, we propose an effective noisy image reconstruction algorithm based on low-rank which introduces the low-rank matrix decomposition and the Augmented Lagrange Multiplier to realize the tradeoff between reconstruction accuracy and reconstruction efficiency. Experimental results verify that the proposed LR algorithm has a superior and stable reconstruction performance on noisy image reconstruction compared with the matching pursuit algorithms.

Background The Yangtze River is the third largest river in the world and suffers from extensive anthropogenic impacts. The fishes in the Yangtze River are essential for the sustainable development of freshwater fisheries and the conservation of aquatic biodiversity in China. However, the fishery resources in the Yangtze River Basin have shown rapid decline due to various human activities. In recent years, nature reserves and germplasm resource reserves have become important means to protect fishes in the Yangtze River. However, nature reserves and germplasm resource reserves that regard freshwater fishes as the main object of protection are not common and have been rarely studied in China. In this paper, a hydroacoustic method and systematic conservation planning tool (Marxan) were combined to evaluate the effectiveness of reserves based on the spatial and temporal patterns of mature fishes in the middle reach of the Yangtze River (MRYR) from 2010 to 2017. Results The hydroacoustic survey results indicated that in the longitudinal direction, low densities of mature fish species were observed in the Jingzhou (S2) and Jianli (S4, S5, S6) sections, whereas high densities of fish were observed in other sections, such as the Yichang (S1), Chenglingji to Huangsangkou (S7–S12), and Hukou (S15) sections. Among the regions preferred by fish, S7, S10 and S12 were non-reserves. No significant difference in mature fish density was observed between the non-reserves and nature reserves, and a similar result was obtained between the non-reserves and germplasm resource reserves. In Marxan, the optimal conservation sites selected for habitat restoration, such as the Chenglingji, Dengjiakou, Zhuankou, Hankou, Yangluo, and Huangsangkou sections, which are located in non-reserves, were identified in the MRYR. Conclusions The Chenglingji, Dengjiakou, Zhuankou, Hankou, Yangluo, and Huangsangkou sections, which are located in non-reserves, play equally important roles in the conservation of fish populations in the MRYR. Our results indicated that further optimization is urgently needed for the currently protected areas in this region. These areas should be designated as reserves, and classification protection mechanisms should be adopted to strengthen the effectiveness of fish conservation in the MRYR.

Although the clinical benefit of laparoscopic splenectomy and devascularization (LSD) has been elaborated in many studies, its application in massive splenomegaly remains controversial. We conducted a retrospective research to assess the curative efficacy of LSD for massive splenomegaly due to portal hypertension. Forty-seven patients with massive splenomegaly due to portal hypertension were enrolled in this study, and divided into two groups. Twenty-one patients underwent open splenectomy and devascularization (OSD) from June 2010 to October 2012 (OSD group). From March 2013 to February 2015, LSD was performed on 26 patients (LSD group). Perioperative variables were analyzed. Compared to OSD, LSD was associated with less blood loss (241.9±110.0 mL vs. 319.0±139.5 mL, P

Nanopore devices have attracted a lot of attention for their potential application in DNA sequencing. Here, we study how an occluding object placed near a nanopore affects its access resistance by integrating an atomic force microscopy with a nanopore sensor. It is found that there exists a critical hemisphere around the nanopore, inside which the tip of an atomic force microscopy will affect the ionic current. The radius of this hemisphere, which is a bit smaller than the theoretical capture radius of ions, increases linearly with the applied bias voltage and quadratically with the nanopore diameter, but is independent of the operation modes and scanning speeds of the atomic force microscopy. A theoretical model is also proposed to describe how the tip position and geometrical parameters affect the access resistance.

The accurate reconstruction of a signal within a reasonable period is the key process that enables the application of compressive sensing in large-scale image transmission. The sparsity adaptive matching pursuit (SAMP) algorithm does not need prior knowledge on signal sparsity and has high reconstruction accuracy but has low reconstruction efficiency. To overcome the low reconstruction efficiency, we propose the use of the fast sparsity adaptive matching pursuit (FSAMP) algorithm, where the number of atoms selected in each iteration increases in a nonlinear manner instead of undergoing linear growth. This form of increase reduces the number of iterations. Furthermore, we use an adaptive reselection strategy in the proposed algorithm to prevent the excessive selection of atom. Experimental results demonstrated that the FSAMP algorithm has more stable reconstruction performance and higher reconstruction accuracy than the SAMP algorithm.

The flow characteristics in a meander channel are fully three-dimensional. With the primary flow in the streamwise direction, the secondary flow in the transverse and vertical directions induced by the channel bends are significant in the analyses of the turbulent structure. Some of the analyses in the straight channel, for instance, the quadrant analysis for the bursting phenomena, are inadequate in investigating the meander channel, since the flow in the transverse direction is not taken into account. In order to reveal the flow characteristics in a multi-bend meander channel, especially, the bursting process, experiments are conducted in the present study. With the three-dimensional quadrant analysis, the influence of the transverse flow velocity during the bursting process could be correctly addressed. The analyses and discussions are presented in this paper.

Recently, nanopores have been used in an essential technique for detecting single molecule with high sensitivity. The initial application of nanopores to DNA and RNA sequencing has been expanded to sensing proteins and nanoparticles, including Bovine serum albumin, silica nanoparticles, polystyrene beads, and others. In our study, for the first time, a positively charged gold nanorod was investigated using a solid-state nanopore device. Various gold nanorods passed through the nanopore with different current blockages and duration times, providing a measurement of the nanorod diameter, length, and charge. Our findings indicate that nanopore sensing might be a new method for characterizing the size, shape, and charge of nanoparticles.

Dysregulation of hedgehog signaling has been involved in esophageal squamous cell carcinoma (ESCC) by the mechanisms that are not fully understood. The receptor for activated protein kinase C (RACK1) is involved in the progression of multiple cancers. However, its expression and function in ESCC have not been investigated. Here, we found that the expression of RACK1 was upregulated in ESCC clinical samples. Moreover, over-expression of RACK1 in ESCC cells promoted cell proliferation and migration, while downregulation of RACK1 impaired the proliferation and migration of ESCC cells in vitro and in vivo. Mechanistically, RACK1 promoted the proliferation and migration of ESCC cells by activating hedgehog signaling. Taken together, our study suggested RACK1 might be an important therapeutic target in ESCC.

A process-based 3-D hydrodynamic model is established to simulate the rip current structures under irregular bathymetry. The depth-varying wave-induced residual momentum, the surface rollers, the turbulent mixing and the wave-current interactions are considered. Experimental datasets are used to validate the model, and it is shown that the model can effectively describe the 3-D structures of the rip currents in both normal and oblique wave incident cases. The flow patterns of the rip currents see various characteristics for different incident wave directions. In the normal incident case, pairs of counter-rotating primary circulation cells are formed, and an offshore rip flow occurs in the embayment troughs. The peak seaward velocities occur at the top of the bed boundary layer, and the undertow is incorporated in addition to the rip currents. In the oblique incident case, the longshore currents are dominant, which result in a meandering flow along the depth contour, and the undertow is weaker compared to that in the normal incident condition.

A three-dimensional (3-D) numerical model is established to investigate the tidal current motion characteristics around the harbor entrance. Computational approaches consist of the finite difference method, time-splitting technique, C-grid, and a high-order turbulence closure model. The Ocean General Circulation Model (OGCM) inundation scheme is incorporated in the model. An engineering application, Lianyungang Harbor, China, is used as a real-life case. The model is validated by showing that the simulated results agree well with the field data. In the approach channel, the tidal current shows a deflection effect especially in the bottom layer. As for Lianyungang Harbor, a jet flow forms at the tip of the northern breakwater, which drives a circulation flow at the inner side of the harbor entrance. In the vertical, the flow is significantly stratified at the entrance section within the channel, where the flow direction varies between layers and the speed distribution is quite uniform. These 3-D features become less evident to the offshore. Additionally, the sensitivity analysis shows that the flow deflection is related to the channel depth. Simulation results also imply that the siltation rate at the entrance section of the approach channel tends to be more uniform by the 3-D flow motion feature, and could be more significant with the increase of the channel depth.

BackgroundThe posterior and anterior circumflex humeral artery (PCHA and ACHA) are crucial for the blood supply of humeral head. We aimed to identify simple landmarks for guiding the quick access to PCHA and ACHA, which might help to protect the arteries during the surgical management of proximal humeral fractures.MethodsTwenty fresh cadavers were dissected to measure the distances from the origins of PCHA and ACHA to the landmarks (the acromion, the coracoid, the infraglenoid tubercle, the midclavicular line) using Vernier calipers.ResultsThe mean distances from the origin of PCHA to the infraglenoid tubercle, the coracoid, the acromion and the midclavicular line were 27.7 mm, 50.2 mm, 68.4 mm and 75.8 mm. The mean distances from the origin of ACHA to the above landmarks were 26.9 mm, 49.2 mm, 67.0 mm and 74.9 mm.ConclusionOur study provided a practical method for the intraoperative identification as well as quick access of PCHA and ACHA based on a series of anatomical measurements.

Most of DNA strand exchange reactions in vitro are based on toehold strategy which is generally nonequilibrium, and intracellular strand exchange mediated by proteins shows little sequence specificity. Herein, a new strand exchange promoted by equilibrious DNA conformational switching is verified. Duplexes containing c-myc sequence which is potentially converted into G-quadruplex are designed in this strategy. The dynamic equilibrium between duplex and G4-DNA is response to the specific exchange of homologous single-stranded DNA (ssDNA). The SER is enzyme free and sequence specific. No ATP is needed and the displaced ssDNAs are identical to the homologous ssDNAs. The SER products and exchange kenetics are analyzed by PAGE and the RecA mediated SER is performed as the contrast. This SER is a new feature of G4-DNAs and a novel strategy to utilize the dynamic equilibrium of DNA conformations.