Origin of beaded tafoni in cliffs of Danxia landscapes,Longhushan Global Geopark, South China

The tafoni that develop in sandstone cliffs have attracted the interest of both scientists and the general public. A necklace-like tafone system, referred to here as beaded tafoni, has developed in the prominent cliffs of the Danxia landscapes within the Longhushan Global Geopark in the subtropical zone of South China. This paper presents a new model of the formation of this system of extraordinary beaded tafoni. The cliffs of the Danxia landscapes of the study area are composed of an alluvial conglomerate(i.e.,red beds). These Danxia landscapes have subrounded summits that are covered by vegetation and experience a nearly vertical water flow induced by gravity. Erosion and collapse of the outsized gravels and concentrated pebbles in the red beds give rise to the initial development of the beaded tafoni. The tafoni then become rounded and beaded as a result of reworking and decay by fluvial outwash. During storms, intense water flows run vertically down the cliffs and generate a whirling motion in the tafoni.Consequently, the inside walls of the tafoni gradually become wider and smoother. During the late development stage, the beaded tafoni tend to become indistinct or disappear because of the interconnection of the tafoni and subsequent merging with the bedding-controlled cavities.

Effects of Polyethylene Oxide Concentration on the Size of Beads in Electrospun Beaded Nanofibers

Embedding particle drugs in beaded nanofibers by electrospinning has been shown a potential approach to control drug release in tissue engineering. The bead size is one of the critical parameters in controlling the drug release rate. In this study,the relationship between polymer concentration and beads size was investigated. Aqueous polyethylene oxide( PEO) solutions with different concentrations were prepared to obtain various beaded nanofibers by electrospnning. Optical microscope and scanning electron microscope( SEM) were used to observe the variation tendency of bead size. With an increase in the polymer concentration,the diameter of fibers between beads became bigger,while the fiber uniformity improved. In addition, the polymer concentration influenced the distribution of bead diameter. Higher polymer concentration would reduce the possibility of small-sized beads formation and improve the uniformity of bead diameter. The study provides a possible way to control the size of beads,which is helpful for further research on the control of particle drug release.

Beaded Fiber Mats of PVA Containing Unsaturated Heteropoly Salt

Poly(vinyl alcohol) (PVA) fiber mats containing unsaturated heteropoly salt was prepared for the first time. IR, X-ray diffraction and SEM photographs characterized the beaded fiber mats. The viscoelasticity and the conductivity of the solution were the key factors that influence the formation of the beaded fiber mats.

Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions.The core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calcium ions(Ca^(2+)).The shell,composed of a chitosan/activated carbon mixture,was then coated onto the core.Fourier transform infrared spectroscopy confirmed the grafting polymerization of acrylamide onto sodium alginate.Scanning electron microscopy images showed the core-shell structure.The core exhibited a high water uptake ratio,facilitating the diffusion of methylene blue into the core.During the diffusion process,the methylene blue was first adsorbed by the shell and then further adsorbed by the core.Adsorption tests showed that the coreshell structure had a larger adsorption capacity than the core alone.The shell effectively enhanced the adsorption capacity to methylene blue compared to the single core.Methylene blue was adsorbed by activated carbon and chitosan in the shell,and the residual methylene blue diffused into the core and was further adsorbed.

Drug-eluting bead transarterial chemoembolization as neoadjuvant therapy pre-liver transplantation for advanced-stage hepatocellular carcinoma

BACKGROUND The objectives of this study were to assess the safety and efficacy of drug-eluting bead transarterial chemoembolization(DEB-TACE)as neoadjuvant therapy before liver transplantation(LT)for advanced-stage hepatocellular carcinoma(HCC)and to analyze the prognostic factors.AIM To determine whether DEB-TACE before LT is superior to LT for advanced-stage HCC.METHODS A total of 99 individuals diagnosed with advanced HCC were studied retrospectively.The participants were categorized into the following two groups based on whether they had received DEB-TACE before LT:DEB-TACE group(n=45)and control group(n=54).The participants were further divided into two subgroups based on the presence or absence of segmental portal vein tumor thrombus(PVTT).The DEB-TACE group consisted of two subgroups:Group A(n=31)without PVTT and group B(n=14)with PVTT.The control group also had two subgroups:Group C(n=37)without PVTT and group D(n=17)with PVTT.Data on patient demographics,disease characteristics,therapy response,and adverse events(AEs)were collected.The overall survival(OS)and recurrence-free survival(RFS)rates were assessed using Kaplan-Meier curves.Univariate and multivariate Cox regression analyses were conducted to determine the parameters that were independently related to OS and RFS.RESULTS The DEB-TACE group exhibited an overall response rate of 86.6%.Following therapy,there was a significant decrease in the median alpha-fetoprotein(AFP)level(275.1 ng/mL vs 41.7 ng/mL,P<0.001).The main AE was post-embolization syndrome.The 2-year rates of RFS and OS were significantly higher in the DEB-TACE group than in the control group(68.9%vs 38.9%,P=0.003;86.7%vs 63.0%,P=0.008).Within the subgroups,group A had higher 2-year rates of RFS and OS compared to group C(71.0%vs 45.9%,P=0.038;83.8%vs 62.2%,P=0.047).The 2-year RFS rate of group B was markedly superior to that of group D(64.3%vs 23.5%,P=0.002).Results from multivariate analyses showed that pre-LT DEB-TACE[hazard ratio(HR)=2.73,95%confidence interval(CI):1.44-5.14,P=0.04],overall target tumor diameter≤7 cm(HR=1.98,95%CI:1.05-3.75,P=0.035),and AFP level≤400 ng/mL(HR=2.34;95%CI:1.30-4.19,P=0.009)were significant risk factors for RFS.Additionally,pre-LT DEBTACE(HR=3.15,95%CI:1.43-6.96,P=0.004)was identified as a significant risk factor for OS.CONCLUSION DEB-TACE is a safe and efficient therapy for advanced-stage HCC and also enhances patient survival after LT.

A Different Brachistochrone Problem with Counterintuitive Results

A problem similar to the famous brachistochrone problem is examined in which, instead of a smooth curve, the path consists of two straight-line sections, one slant and one horizontal. The condition for minimum sliding time is investigated, producing results that are both counterintuitive and interesting.

基于PSO-BP神经网络的双相不锈钢电弧增材制造焊道成形预测

Duplex stainless steel was formed through welding wire and arc additive manufacturing(WAAM)using tungsten inert gas.The effects of wire feeding speed(WFS),welding speed(WS),welding current,and their interaction on the weld bead width and height were discussed.Back-propagation(BP)neural network algorithm prediction model was established by taking the bead width and height as the output layer,and the network weight and threshold values were optimized using the particle swarm optimization(PSO)algorithm to obtain the prediction model of bead width and height.The predicted results were verified by experiments.Results show that the weld bead width increases with the increase in WFS and the welding current and decreases with WS.The smaller the WFS,the faster the WS,which is beneficial for the generation of equiaxed crystals.The smaller the welding current,the faster the cooling speed of the metal melt,which is conducive to the formation of dendrites.The interaction among WS,wire feed speed,and welding current has a significant effect on the bead width.The weld bead height is positively correlated with the wire feed speed and negatively correlated with the WS and current.The interaction between the wire feed speed and WS is significant.The optimized WAAM process parameters for duplex stainless steel are a wire feed speed of 200 cm/min,WS of 24 cm/min,and welding current of 160 A.The maximum error of the BP neural network in predicting the weld bead width and height is 7.74%,and the maximum error between the predicted and experimental values of the BP-PSO neural network is 4.27%.This finding indicates that the convergence speed is fast,improving the prediction accuracy.

H_4SiW_(12)O_(40)/TiO_2/beads光催化降解亚甲基蓝的研究

以钛酸四丁酯为原料,空心微珠为载体,采用溶胶-凝胶法制备TiO2/beads光催化剂载体,然后浸渍法制备出H4SiW12O40/TiO2/beads表面负载修饰型复合光催化剂,并运用SEM、XRD、FT-IR和DRS对催化剂进行表征和分析。研究了H4SiW12O40/TiO2/beads对亚甲基蓝降解的光催化活性,考察了光强度、pH值、曝气量、底物浓度和催化剂用量等对催化效率的影响。实验结果表明,在中性条件下,H4SiW12O40/TiO2/beads催化剂的投加量为0.25 g/L,浓度为7.5 mg/L的亚甲基蓝溶液在250 W的紫外灯和600 W的可见光灯下光照60 min降解率分别可达到94.5%和55%。

愈风宁心片中葛根素在Beagle犬体内药动学研究

目的:研究愈风宁心片(葛根总黄酮)中主要有效成分葛根素在狗体内的药-时曲线,计算其在狗体内的药动学参数;并与静注葛根素注射液比较,研究愈风宁心片中葛根素的绝对生物利用度。方法:本文应用自身对照设计试验法,单剂量一次给予狗静脉注射葛根素注射液或口服愈风宁心片。采用HPLC法测定狗血浆中葛根素的浓度,应用PK solu-tions 2.0程序计算药动学参数和生物利用度。结果:静脉注射葛根素注射液(9 mg/kg)的药动学参数分别为:t1/2E=(72.11±3.69)m in,CL=(4.19±0.25)mL/m in,AUC(0-∞)=(2 172.42±123.02)μg/m in/mL。口服愈风宁心片(相当于葛根素10.49 mg/kg)的药动学参数分别为t1/2E=(271.80±7.94)m in,CL=(48.52±2.20)mL/m in,Cm ax=(0.43±0.06)μg/mL,Tm ax=150 m in,AUC(0-∞)=(185.77±8.20)μg/m in/mL,绝对生物利用度为7.03%。结论:狗口服愈风宁心片片中葛根素在狗体内的吸收较少,生物利用度较低。

Construction Fractional Genomic Libraries and Screening Microsatellites DNA of Esox reieherti Dybowski

Esox reieherti Dybowsk genomic microsateUites were developed by using enrichment protocols combined with radioactive hybridization protocol. Four hundred to nine hundred base pair fragments were selected for the whole genome. DNA PCR amplification after digestion with restriction endonuclease Sau 3A Ⅰ, and （CA）12, （GA）12 probes marked with biotin were used for microsateUite DNA enrichment. The product fragments were connected with carder pGEM-T and transferred into DH5α Escherichia coli competent cells, and radioactive isotope probes marked with γ^-32 p were used for the second hybridization. As a result, a total of 1600 bacteria were obtained in the microsatellite genomic libraries, positive clones accounted for 90.91% before hybridization and 81.25% after hybridization, amounting to 1300. One hundred and ninety-six positive clones were selected for sequencing, and 192 clones included microsateUite sequences. The microsateUite sequences obtained, mono-nucleotide, quad-nucleotide and quint-nucleotide repeat motifs were observed beside double-base-pairs CA/GT, GA/CT. Seventy primers were designed according to the flanking sequences by using software Primer Premier 5.0, and 32 primers were selected to be synthesized. After optimizing PCR reaction conditions, 28 primers were amplified and produced clear purpose bands. The aim of our research was to promote the development and utilization of E. reieherti genomic resource, and lay the foundation for optimizing E. reieherti breeding strain in order to detect the genetic diversity and construct a genetic map.

Enhanced photocatalytic performance of cementitious material with TiO_2@Ag modified fly ash micro-aggregates

A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead（ZFAB） to improve its dispersability and exposure degree in a cement system.The application of Ag particles in TiO2/ZFAB modified cementitious materials is to further enhance the photocatalytic performance.Various Ag@TiO2/ZFAB modified cementitious specimens with different Ag dosages are prepared and the characteristics and photocatalytic performance of the prepared samples are investigated.It is observed that the multi-level pore structure of ZFAB can improve the exposure degree of TiO2 in a cement system and is also useful to enhance the photocatalytic efficiency.With an increment of the amounts of Ag particles in the TiO2/ZFAB modified cementitious samples,the photocatalytic activities increased first and then decreased.The optimal Ag@TiO2/ZFAB modified cementitious sample reveals the maximum reaction rate constant for degrading benzene（9.91×10^-3 min^-1）,which is approximately 3 and 10 times higher than those of TiO2/ZFAB and TiO2 modified samples,respectively.This suggests that suitable Ag particles coupled with a ZFAB carrier could effectively enhance the photocatalytic effects and use of TiO2 in a cement system.Thus,ZFAB as a carrier could provide a potential method for a high efficiency engineering application of TiO2 in the construction field.

TiO_2·SiO_2/beads降解有机磷农药的研究

研究以四氯化钛 ,硅酸乙酯为原料 ,以空心玻璃微球为载体 ,用浸涂法制备TiO2 ·SiO2 /beads负载型复合光催化剂的过程。对利用负载型复合光催化剂降解有机磷农药进行了活性评价。结果表明 :TiO2 ·SiO2 /beads光活性显著提高 ,最佳光催化剂活性是同样降解条件下、同样含量的DegussaP - 2 5TiO2 光活性的 1.35倍左右。另外 ,对TiO2 ·SiO2 /beads的吸附性和比表面进行测试 ,同时从微观角度对负载型复合光催化剂的表面状态和光催化剂颗粒尺寸进行分析。

附载型复合光催化剂TiO_2·SiO_2/beads降解有机磷农药

研究以四异丙醇钛 [Ti( iso- O C3 H7) 4]、硅酸乙酯为原料 ,以空心玻璃微球为载体 ,用溶胶—凝胶法制备可漂浮附载型复合光催化剂 Ti O2 · Si O2 / beads的过程 ,利用附载型复合光催化剂降解有机磷农药。结果表明 ,复合型光催化剂 Ti O2 · Si O2 摩尔比存在最佳值 ,n ( Ti O2 ) / m ( Si O2 ) =30 / 70时 ,光催化剂活性最高 ,其活性是同样降解条件下、同样含量 Degussa P- 2 5Ti O2 的 2倍左右。该光催化剂比表面大 ,吸附性强。并用 XRD和

Bead模型的不确定性范围查询与修剪算法

针对时空范围内,移动目标数据库中由于移动目标轨迹的不确定性导致的范围查询问题,在基于Bead/Necklace不确定性模型的基础上,将查询问题映射为2D平面的计算几何问题进行解决。针对时空中五种不同句法的不确定性范围查询类型确定了对应的定性查询算法,并通过查询多边形的偏置和轨迹点位置查询的方法实现新的修剪算法,其算法复杂度与查询区域边的数目呈线性关系。实验结果显示,提出的修剪策略更加有效地提高了系统的查询效率。

载药动脉栓塞微球DC Bead^(TM)研究进展

载药洗脱微球结合了栓塞与局部化疗的优势,其经微导管注射,选择性对肿瘤供血动脉进行栓塞,使肿瘤缺血坏死;同时其向病灶部位持久缓慢地释放药物,形成局部高浓度,对肿瘤细胞产生显著的细胞毒效应。近年来载药DC BeadTM用于肝癌的栓塞化疗研究取得了较快的发展。本文就其制备方法、载药特点、体外释放方法、体内药动学及临床研究等方面进行了综述。

溶胶-凝胶法制备TiO_2·SiO_2/beads及其光催化性能的研究

研究以四异丙醇钛 [Ti (iso OC3 H7) 4 ]、硅酸乙酯为原料 ,以空心玻璃微球为载体 ,用溶胶 凝胶法制备可漂浮附载型复合光催化剂TiO2 ·SiO2 /beads的过程 ,利用附载型复合光催化剂降解有机磷农药。结果表明 :附载型复合光催化剂活性显著提高 ,牢固性增强 ,TiO2 ·SiO2 摩尔比存在最佳值。n (TiO2 ) /m (SiO2 ) =30 / 70时 ,光催化剂活性最高 ,其活性是同样降解条件下 ,同样含量DegussaP 2 5TiO2 的

Sensitivity model for prediction of bead geometry in underwater wet flux cored arc welding

To investigate influence of welding parameters on weld bead geometry in underwater wet flux cored arc welding （FCAW）, orthogonal experiments of underwater wet FCAW were conducted in the hyperbaric chamber at water depth from 0.2 m to 60 m and mathematical models were developed by multiple curvilinear regression method from the experimental data. Sensitivity analysis was then performed to predict the bead geometry and evaluate the influence of welding parameters. The results reveal that water depth has a greater influence on bead geometry than other welding parameters when welding at a water depth less than 10 m. At a water depth deeper than 10 m, a change in travel speed affects the bead geometry more strongly than other welding parameters.

Spreading pattern and CT findings of very early-stage peripheral small-cell lung cancer

Chest CT frequently reveals small pulmonary lesions. If there is no associated hilar or mediastinal lymphadenopathy, small-cell lung cancer (SCLC) is considered to be very early-stage. Few studies, however, have described the characteristic CT findings of very early-stage SCLC. Clarifying these findings would reduce diagnostic delay. The purpose of this study was to determine the characteristic CT findings of very earlystage SCLC. Computed tomography images obtained from 547 consecutive patients with lung cancer between 2003 and 2012 at Tokyo Dental College Ichikawa General Hospital were reviewed retrospectively. One hundred of these patients had SCLC and 447 had non-SCLC (NSCLC). These CT images, along with any that had also been obtained prior to the one on which the final diagnosis was based, were reviewed. In 5 of the cases reviewed, specific findings and a characteristic spreading pattern were identified on CT images that might have allowed a diagnosis of SCLC to have been made sooner. The findings included a sub-pleural, small nodule accompanied by daughter nodules spreading longitudinally along the bronchovascular bundle, no air bronchogram or cavitation, and background emphysematous change. These were not identified on CT images of very earlystage NCSLC, however (n = 22). Awareness of the relevance of these findings would help physicians and radiologists arrive at a differential diagnosis of small pulmonary nodules.

唾液多肽磁珠提取标准化方法研究

Saliva is a dilute solution of complex mixture containing proteins,glycoproteins,lipids and ions secreted from the major and minor salivary gland.In addition,the components of saliva are similar with that of blood.In this report,peptides and proteins in saliva were separated by magnetic beads and measured by MALDI-TOF-MS.The preparation method of salivary sample was standardized.

探究促生根际菌(PGPR)对黄瓜生长的影响

促生根际菌——Plant Growth Promoting Rhizbacteria菌(简称PGPR),是一种能够促进植物生长、防治病害、增加作物产量的微生物。本试验引进PGPR菌种资源技术,以黄瓜的生长为研究对象,探究了促生根际菌(PGPR)对黄瓜生长的影响。结果表明,在试验中采用的两种促生根际菌假单胞细菌(Pseudomonas putida)和肠杆菌(Enterobacter cloacae)对黄瓜生长的影响不明显。