双能CT水-羟基磷灰石分离技术对胸腰椎骨折诊断的影响:不同年资放射科医生间的比较

目的探讨双能CT(DECT)水-羟基磷灰石(HAP)分离技术能否提高椎体新鲜压缩性骨折的检出率,并研究其诊断效能与放射科医生经验水平的相关性。方法回顾性分析50例创伤后接受胸腰椎DECT和MRI检查的患者资料,DECT获得常规混合能量CT平扫图和水-HAP重建图像。四名放射科医生独立盲法阅片,该四名医生分别具有1年、5年、8年和12年工作经验,首先根据CT平扫判断是否存在椎体骨折及骨折的新旧,再结合DECT水-HAP图来判断有无骨折及骨折的新旧。以MR T2脂肪抑制图像为金标准,进行DECT诊断效能的敏感度、特异度、准确度、阳性预测值、阴性预测值分析以及CT平扫与结合水-HAP图结果配对分析。结果MRI共发现54节新鲜骨折,38节陈旧性骨折。与常规CT平扫相比,结合水-HAP图像提高了所有医生的诊断效能。四名医生结合水-HAP图像后,准确度分别由常规CT的0.76、0.75、0.82、0.84提升至0.87、0.89、0.92、0.93;敏感度和特异度分别由0.83、0.83、0.89、0.87,0.66、0.63、0.71、0.79提升至0.93、0.94、0.98、0.94,0.79、0.82、0.84、0.92;阳性预测值和阴性预测值分别由0.78、0.76、0.81、0.85,0.74、0.73、0.82、0.81提升至0.86、0.88、0.90、0.94,0.88、0.91、0.97、0.92;被评为“不确定”椎体的数量分别由23、21、19、12节下降到7、5、5、1节。与常规CT平扫相比,DECT水-HAP分离技术提高了所有医生诊断新鲜椎体骨折的准确度,配对分析差异具有统计学意义(P<0.05)。水-HAP分离技术使患者也受益,四名医生结合水-HAP图像后,需要进一步MRI检查的患者数量分别由14、13、14、11人下降到4、3、3、1人。结论DECT水-HAP分离技术可提高不同经验水平放射科医生基于CT诊断椎体新鲜压缩性骨折的能力。

羟基磷灰石水悬浮液的稳定性与荷电性研究

以氢氧化钙和磷酸二氢钙为前驱,用均相化学沉淀法合成制备了羟基磷灰石(HAP)。研究了pH值、定势离子(Ca2+,PO43-)浓度及改性剂对HAP水悬浮液的Zeta电位和分散稳定性的影响,探讨了荷电性与分散稳定性的关系。结果表明:Zeta电位的绝对值越大,HAP水悬浮液的稳定性越强。并采用两种具有典型代表性的物质,壳聚糖和明胶对HAP微粒进行改性,得到了稳定的HAP水悬浮液。

能谱CT在评估膝关节急性外伤性骨髓水肿中的应用价值

目的探讨能谱CT在膝关节急性外伤性骨髓水肿中的应用价值。方法选取行能谱CT和MRI检查的急性膝关节外伤患者32例。能谱CT扫描数据传输到后处理工作站AW4.7,以MRI作为参考标准,由2位诊断医师分别利用能谱水-钙(Ca)、水-羟基磷灰石(Hap)彩色编码图像评估骨髓水肿程度,比较两种方法评估骨髓水肿差异有无统计学意义;测量水肿区域的水-Ca、水-Hap值,评价差异有无统计学意义,并利用ROC曲线分析两者在骨髓水肿中的诊断效能。结果32例膝关节外伤,MRI显示骨髓水肿区域146处,能谱CT中:水-Ca彩色编码图像共获得135处水肿区域,灵敏度为95.6%,特异度为98.8%,阳性预测值为96.3%,阴性预测值为98.5%;水-Hap彩色编码图像共获得128处水肿区域,灵敏度为90.4%,特异度为98.8%,阳性预测值为96.1%,阴性预测值为96.9%;MRI、水-Ca、水-Hap三者之间差异无统计学意义(P>0.05)。ROC分析显示在水-Ca中,当相对水含量值为1020.02 mg/cm3时,能谱CT对骨髓水肿的诊断效能最高,灵敏度99.3%,特异度74.1%,AUC为0.93;在水-Hap中,当相对水含量值为953.99 mg/cm^(3)时,能谱CT对骨髓水肿的诊断效能最高,灵敏度88.1%,特异度93.3%,AUC为0.96,差异有统计学意义(P<0.001)。结论能谱CT的水-Ca、水-Hap均可以清晰显示急性膝关节外伤患者的骨髓水肿区域,并精准定量评估:MRI、水-Ca、水-Hap彩色编码图像显示骨髓水肿区域差异无统计学意义;利用ROC曲线分析显示水肿区域的水-Ca、水-Hap值在骨髓水肿中的诊断效能差异有统计学意义。

双能量CT羟基磷灰石-水分离技术在隐匿性骨折诊断中的应用价值

目的:探讨双能量CT羟基磷灰石(HAP)-水分离技术在隐匿性骨折临床诊断中的应用价值。方法:选取2019年12月—2020年12月重庆市铜梁区人民医院收治的高度怀疑隐匿性骨折患者68例作为研究对象。以MRI诊断结果作为参考标准,对所有患者双能量CT VNHAP融合伪彩图进行视觉评估并测量虚拟去HAP图像(VNHAP)灰度图中局部骨质相对水含量,计算双能量CT HAP-水分离技术在隐匿性骨折中的诊断结果以及骨质相对水含量差异。结果:68例患者经MRI检查明确诊断为隐匿性骨折患者59例,双能量CT HAP-水分离技术对其敏感度为96.61%(57/59),特异度为88.89%(8/9),准确度为95.59%(65/68),并且59例隐匿性骨折患者的VNHAP灰度图中急性期隐匿性骨折局部骨质相对水含量(1028.49±14.86)mg/cm^(3)高于慢性期的(989.96±12.44)mg/cm^(3),差异有统计学意义(t=10.080,P<0.05)。结论:双能量CT HAP-水分离技术通过对融合伪彩图以及骨质相对水含量的计算可实现隐匿性骨折的有效诊断以及急慢性期骨折的鉴别诊断,且CT检查更为方便、快捷,对患者限制相对较少,具有应用及推广价值。

Acid mine drainage activation mechanism on lime-depressed pyrite flotation from copper sulfide ore

The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of laboratory flotation tests and surface analytical techniques.Flotation test results indicated that AMD could effectively activate the pyrite flotation with a sodium butyl xanthate(SBX)collector,and a high-quality sulfur concentrate was obtained.Pulp ion concentration analysis results indicated that AMD facilitated desorption of Ca^(2+)and adsorption of Cu^(2+)on the depressed-pyrite surface.Adsorption measurements and contact angle analysis results confirmed that adding AMD improved the adsorption amount of SBX collector on the pyrite surface and increased the contact angle by 31°.Results of Raman spectroscopy and X-ray photoelectron spectroscopy analysis indicated that AMD treatment promoted the formation of hydrophobic species(S^(0) hydrophobic entity and copper sulfides)and the removal of hydrophilic calcium and iron species on the pyrite surface,which reinforced the adsorption of collector.The findings of the present research provide important theoretical basis and technical support for a cleaner production of copper sulfide ores.

粉煤灰细水泥的配制及浆液性能的研究

本文通过试验得出 ,以粉煤灰为主要原料 ,加入一定的外加剂 ,可以配制出适合表土层注浆的、细度大于 45 μm占 9%的、强度满足 42 5 #水泥强度的细水泥。该水泥也可以用作其它建筑物的低热水泥。

新型除氟滤料在河南濮阳地区农村饮用水安全工程中的应用

濮阳地区是河南省高氟地下水分布最严重的地区之一。采用自主研发的新型碳基磷灰石除氟滤料对濮阳地区高氟水分别进行微柱测试、家用净水机试验以及集中供水工程设备的出水监测。考察了微柱中新型除氟滤料与常见的活性氧化铝、活化沸石除氟滤料在相同条件下的性能比较,测试了家用净水机的再生性能,监测了集中供水除氟设备的出水氟含量。结果表明,新型碳基磷灰石除氟滤料性能显著,相同条件下除氟性能是活性氧化铝的5.09倍,是活化沸石的11.7倍,出水氟含量小于0.2 mg/L,再生后除氟性能稳定,完全符合《生活饮用水卫生标准》(GB 5749-2006)的要求。因此,能够适应濮阳地区农村饮用水安全的高氟水处理。

Early calcium monocarboaluminate hydrate formation in cement paste:effect of polycarboxylate type admixture

Effects of polycarboxylate type admixture（PCA）on calcium monocarboaluminate hydrate（AFmc）formation in hydrated cement paste containing limestone filler（LF）are investigated by the Fourier transform infrared spectroscopy（FTIR）,the scanning electron microscopy（SEM）,the derivative thermogravimetric（DTG）analysis and the adsorption amount measurement.Experimental results indicate that AFmc forms during the initial hydration period of cement as early as 15 min.It is found that PCA accelerates the early age AFmc formation and enhances cement hydration by promoting C4AF hydration at the early age,and,as a consequence,the iron associated AFmc phase forms more readily.The phenomenon is not observed when PCA is replaced by a naphthalene formaldehyde sulphonate condensate water reducer.Compatibility between PCA and cement is modified due to the presence of AFmc along with ettringite（AFt）,which results in a less adsorption amount of PCA on the surface of cement minerals.As a kind of high-range water reducer,PCA may be the preferred choice for concrete containing LF.

Arginine functionalized hydroxyapatite nanoparticles and its bioactivity for gene delivery

In order to further improve the transfection efficiency of hydroxyapatite nanoparticle （HAp）, arginine functionalized hydroxyapatite （HAp/Arg） was synthesized by hydrothermal synthesis. The morphology, crystallite size and zeta potential of the HAp/Arg were characterized by transmission electron microscopy （TEM）, atomic force microscopy （AFM） and zeta potential analyzer. The loading and protecting properties of HAp/Arg to DNA were tested by electrophoresis. Its cytotoxicity was also measured in Hela cells and HAEC cells by MTT and LDH, and its transfection efficiency was examined by fluorescence microscope and flow cytometry. The results reveal that HAp/Arg is short rod-like and nano single crystal, the mean diameter is 50-90 nm and zeta potential is 35.8 mV at pH 7.4. HAp/Arg to DNA can be condensed by electrostatic effect and protect DNA against degradation in DNase I, and shows high transfection efficiency without cytotoxicity. These results suggest that HAp/Arg can be a promising alternative as a novel gene delivery system.

Synthesis of Crystalline Hydroxyapatite from CaCO_3 and CaHPO_4·2H_2O by Mechanochemical Method

The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.

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.

Ordovician limestone aquosity prediction using nonlinear seismic attributes:Case from the Xutuan coal mine

Ordovician limestone water is coal mines. In this paper, we analyze the the main source of water inrush in North China characteristic of three kinds of nonlinear seismic attributes, such as the largest lyapunov exponent,fractal dimension and entropy and introduce their calculation methods. Taking the 81st and 82nd coal districts in the Xutuan coal mine as examples, we extract the three seismic attributes based on the 3D prestack migration seismic data of this area, which can display the Ordovician limestone fracture distribution in the mine. We comprehensively analyzed the three nonlinear seismic attributes and compared the results with transient electromagnetic exploration results and determined the possible Ordovician limestone aquosity distribution. This demonstrated that the nonlinear seismic attributes technology is an effective approach to predict the aquosity of Ordovician limestone.

Effects of ball milling time on porous Ti-3Ag alloy and its apatite-inducing abilities

Ti and Ag powders were mixed with different ball milling time （1, 2, 5 and 10 h） and sintered into porous Ti-3Ag alloys. The samples were treated with hydrothermal treatment, and their apatite-inducing abilities were further evaluated by immersion in modified simulated body fluid. The results indicate that the high surface energy brought by powder refinement leads to the decline of Ag, but promotes the oxidation of Ti during the sintering process. Meanwhile, the hydrothermal treated porous Ti-3Ag alloys prepared by the powders ball milled for 10 h possess the best apatite-inducing ability.

APPROACH OF DETERMINISTIC GEOMORPH OLOGIC INSTANTANEOUS UNIT HYDROGRAPH TO HYDROLOGICAL PROCESSES' SIMULATION IN KARST AREA

In order to analyze the condition of s pecial landform and regularity of sp ecial hydrological movement in karst area,the method of Geomorphologic Instantaneous Unit Hydrograph(GIUH)has been used to divide the river net-works into three grades in the research area and the karst hydrologic processes were simulated with Nash insta ntaneous u-nit hydrograph(NIUH).The combination of the GIUH and NIUH fully considers the moving path of wa ter particles in drainage and the regional composition of runoff at the end of the drainage,resulting in a rational combinatio n of probabili-ty of GIUH and NIUH and geomorphologic parameters which could reflect the complexity of the landform structur e of karst drainage.The results showed t hat the combined method of GIUH and NI UH has clear physical concept and acc ept-able precision,which can be widely a pplied on hydrological studies of karst area.

Leaching behaviors of calcium and magnesium in ion-adsorption rare earth tailings with magnesium sulfate

The leaching behaviors of calcium and magnesium in the rare earth tailings leached with magnesium sulfate using deionized water,CaCl2 solution and lime water were investigated.Experimental data indicated that magnesium in the tailings was easy to be leached out since most of the magnesium was in the form of water-soluble phase.Most of calcium in the lime water was electrostatically adsorbed on the clay mineral of the tailings,and the water-soluble magnesium was also gradually converted into exchangeable phase because of back-adsorption of Mg2+on the clay mineral with increasing the pH values.When the liquid-to-solid ratio was 0.80,the contents of readily-available magnesium and calcium were 104.4−207.6 and 201.7−1426.3 mg/kg,respectively,which could meet the requirements for plants.These results suggest a promising route for the environmental remediation of ion-adsorption rare earth ore after in-situ leaching.

Effect of Additives on the Morphology of the Hydrated Product and Physical Properties of a Calcium Phosphate Cement

The morphology of a hydrated calcium phosphate cement （CPC） doped with several normally used additives was investigated by scanning electron microscopy （SEM） and the compressive strength of the cement was determined in this study. The hydrated products of CPC without additives was rod-like hydroxyapatite （HA） grains with around 2-5 μm in length and 100 nm in width. The addition of Sr obviously decreased the crystal size of the rod-like grains. CPCs containing carbonate, collagen and gelatin showed flake-like crystal morphology. Crylic acid-containing CPC presented flocculus-like structure. And malic acid-containing CPC exhibited oriented flake-like structure. The X-ray diffraction （XRD） analysis showed that the additives used in this study did not alter the hydration products of the cement. The compressive strength tests indicated that the compressive strength of the cement with rod-like morphology HA crystals was much higher than that of the cement with flake-like morphology HA crystals, and the cement with oriented flake-like morphology HA crystals exhibited the poorest compressive strength.

Remediation Effects of Water Management and Lime Application on Seasonally-Fallowed Cd-Contaminated Paddy Fields

In the light of the national policy of fallow, this study was conducted to determine how the different water management and lime application would affect soil physical and chemical properties, rice yield and cadmium （Cd） content of rice in fallow season. The results showed that, compared with the arid fallow, the waterlogging fallow decreased the soil pH value whereas signifcantly increased the soil organic matter content and the cation exchange quantity, and reduced the soil effective cadmium content and the rice cadmium content whereas could increase the rice yield to a certain extent. In the fooded fallow or the dry fallow, the application of lime mainly depended on the alkali conditioning of lime and the antagonistic effect of Ca2＋, which could signifcantly reduce the cadmium content of rice, and its effect would increase linearly with the increase of lime dosage, whereas had no significant effect on soil organic matter content and cation exchange quantity. In order to establish a linear equation of lime dosage and related indexes under the condition of waterlogging fallow or dry fallow, calculations showed that each application of lime at 1 000 kg/hm2 or kg/hmss2 could improve soil pH value by 0.238 2 or 0.246 5units respectively, and reduce the effective Cd content to 0.007 5 mg/kg both in the arid fallow and the waterlogging fallow conditions. The lime theoretic application rate for the lowest Cd content of late rice in the arid fallow was 5 120 kg/hm2, and the minimum limit of the Cd content in rice was 0.124 2 mg/kg; and the lime theoretic application rate for the highest yield of late rice in the submerged water fallow was 4 636 kg/hm2, the minimum theoretic Cd content in rice is 0.100 7 mg/kg, and it could reduce the Cd content in rice under the condition of submerged fallow and decrease the dosage of lime.

Water abundance of mine floor limestone by simulation experiment

The water abundance of mine floor limestone needs to be solved urgently as the average depth of coal mining in China has increased gradually. A method is presented to discuss water abundance with the numerical and physical layered geoelectrical model being established in the half-space, full-space and full-space with tunnel, respectively. The parameters of water abundance are changed in this study, which includes water quantity, water content and volume of abnormity of water-containing abnormity. Results indicate that the different work fields have different macroscopic influences on the apparent resistivity,and the water abundance parameters of water-containing abnormity have quantitative relationship with the apparent resistivity mean in abnormal regions(three-dimensional space region). The quantitative relationships are shown as following: firstly, the amount of water injection has negative linear correlation with the apparent resistivity mean; secondly, when abnormity is unsaturated, there is a negative power function relationship between water content and apparent resistivity mean; thirdly, the volume of abnormity and apparent resistivity mean behave as a decreasing power function law.

Removal of Cu2＋ from Aqueous Solutions Using Na-A Zeolite from Oil Shale Ash

Na-A zeolite was synthesized using oil shale ash （OSA）, which is a solid by-product of oil shale proc- essing. The samples were characterized by various techniques, such as scanning electron microscopy, X-ray diffrac- tion and Brunaner Emmet Teller method. The batch isothermal equilibrium adsorption experiments were performed to evaluate the ability of Na-A zeolite for removal of Cu （II） from aqueous solutions. The effects of operating pa- rameters, such as concentration of copper solutions, adsorbent dosages, pH value of solutions and temperature, on the adsorption efficiency were investigated. The equilibrium adsorption data were fitted with Langmuir and Freundlich models. The maximum adsorption capacity of Na-A zeolite obtained from the Langmuir adsorption iso- therm is 156.7 mg.g-t of Cu （lI）. The increase of pH level in the adsorption process suggests that the uptake of heavy metals on the zeolite follows an ion exchange mechanism. The batch kinetic data fit the pseudo-second order equation well. The thermodynamic parameters, such as changes in Gibbs free energy （AG）, enthalpy （AH） and en- tropy （AS）, are used to predict the nature of the adsorption process. The negative AG values at different tempera- tures confirm that the adsorption processes are spontaneous.

Contribntion of Iron Phosphate in Calcareous Paddy Soils to Phosphorus Nntrition of Rice Plant

A study was carried out on contribution of iron pbosphate to phosphorus nutrition of rice plant nnderwaterlogged and moist conditions, respectively, by use of synthetic Fe￣(32) PO_4 . nH_2O, tagging directly the ironphophate in calcareous paddy soils.Results showed that under waterlogged condition, similar to iron phosphate in acidic paddy soils, that incalcareous paddy soils was an important source of phosphorus to rice plant, and the amount of phosphorusoriginated from it generally constituted 30-65% of the total phosphorus absorbed by rice plant.