Discussion on the Mechanism of Boric Acid and Phosphoric Acid to Improve the Hardening of Complex Calcium Lubricating Grease

In order to solve the hardening problem of complex calcium lubricating grease, the water absorption test of several calcium salts was carried out, and it was found that calcium 12-hydroxystearate did not absorb water, and calcium acetate, calcium phosphate and calcium borate had different degrees of water absorption. Calcium acetate has the highest water absorption rate, while calcium phosphate and calcium borate show comparable water absorption rates. Upon using the molecular simulation technology, it is found that in the complex calcium grease system, calcium phosphate and calcium borate tend to combine with water, which inhibits the water absorption of calcium acetate and alleviate the hardening problem.

Effects of Compound Silicate Gangue on Formation of Complex Calcium Ferrite During Sintering Process

In order to improve the quality of sinter produced by Baiyunebo iron ore concentrate,the effects of compound silicate gangue containing kalium and natrium on formation of complex calcium ferrite were studied using mini-sintering test device,optical microscope（OM） analysis and scanning electron microscope（SEM）/energy dispersive X-ray spectroscopy（EDX） analysis.The results show that with the increasing of K2O and Na2O content in sintering samples,K2O and Na2O highly enriched in the glassy phases,the contents of complex calcium ferrite and hematite in sinter decreased and the porosity increased;the mineral microstructure exhibited large cavities and thin framework and became inhomogeneous.The compound silicate gangue containing kalium and natrium significantly inhibited the generation of complex calcium ferrite（SFCA）.When the content of K2O and Na2O was higher in samples,a part of K2O and Na2O entered into complex calcium ferrite,which caused the fine grains of SFCA with acicular and columnar to agglomerate into coarse grains,and its bonding effect to iron oxides reduced.The content of K2O and Na2O in sinter had effects on quantity,composition and morphology of complex calcium ferrite.

Effect of Al_(2)O_(3)/SiO_(2) ratio on morphology of complex calcium ferrite

Al_(2)O_(3) and SiO_(2) greatly influence the formation of complex calcium ferrite,which is the main bonding phase in high basicity sinters.The effects of Al_(2)O_(3)/SiO_(2) ratios on the morphology of complex calcium ferrite were studied.The main mineral phases in the samples with different Al_(2)O_(3)/SiO_(2) ratios were CaFe_(2)O_(4) with a solid solution of Si or Al atoms and the silico-ferrite of calcium and aluminum.The results showed that the morphology of the complex calcium ferrite changed from lumpy to plate-like and acicular with increases in the SiO_(2) content and the Al_(2)O_(3)/SiO_(2) ratio.When the content of SiO_(2) was 4 wt.%,the main calcium ferrite morphology was acicular,and the number of macropores in the samples increased with the Al_(2)O_(3)/SiO_(2) ratio increasing.The first-principles analysis of the calcium ferrite crystal structure showed that adding SiO_(2) and Al_(2)O_(3) changed the growth mechanism of the CaFe_(2)O_(4) crystal,promoting the formation of platy and acicular complex calcium ferrite.The size of calcium ferrite was significantly smaller due to the increase in CaO-Fe_(2)O_(3)-SiO_(2)-Al_(2)O_(3) viscosity with increasing the Al_(2)O_(3)/SiO_(2) ratio.

Spectrophotometric determination of the formation constants of Calcium(Ⅱ) complexes with 1,2-ethylenediamine,1,3-propanediamine and 1,4-butanediamine in acetonitrile

In this work, with the purpose to explore the coordination chemistry of calcium complexes which could work as a partial model of manganese-calcium cluster, a spectrophotometric study to evaluate the stability of the complexes: Calcium(Ⅱ)-1,2-ethylendiamine, Calcium(Ⅱ)-1,3-propanediamine and Calcium(Ⅱ)-1,4-butanediamine in acetonitrile, were carried on. By processing the spectrophotometric data with the HypSpec program allows the determination of the formation constants. The logarithmic values of the formation constants obtained for Calcium(Ⅱ)-1,2-ethylendiamine, Calcium(Ⅱ)-1,3-propanediamine and Calcium(Ⅱ)-1,4-butanediamine were log β_(110) = 4.69, log β_(110)= 5.25 and log β_(110) = 4.072, respectively.

Crystal Structure of Calcium Complex with Cyanuric Acid Ligand［Ca（C3H3N3O3－O）（H2O）6］［（OH）（C3H2N3O3）］

The title compound[Ca(C3H3N3O3)(H2O)6][(OH)(C3H3N3O3)] crystallizes in the triclinic system,space group P1,with a=6.501(5),b=10.814(6),c=11.803(1) A,α=103.64(1),β=92. 72(3),γ=98. 82(4)°,V=793- 9(7) A3,Dc=l.77 g/cm3,Z=2,Mr=422. 32,λ(MoKα)=0.71069 A,μ=4.65 cm-1,F(000)=440,final R=0.045 and Rω=0.058 for 3422 observable reflections with I≥3σ(I).In the complex cation [Ca (C3H3N3O3)(H2O)6]2+,the Ca2+ is coordinated by an oxygen atom from cyanuric acid ligand and six oxygen atoms from water molecules forming a distorted pentagonal bipyramid geometry.The complex anions, OH- and C3H2N3O3-,are bound with the complex cation[(Ca(C3H3N3O3)(H2O)6]2+ by electrostatic force to form the title compound.

Preparation of Overbased Calcium Alkylbenzene Sulfonate for Formulating Complex Sulfonate Grease

Six kinds of alkylbenzene sulfonic acids were selected to prepare the sulfonates S1—S6. Among them, the sulfonates S3, S4, and S6 could be incorporated into lubricating grease with good performance in comparison with the grease produced from commercial sulfonates T106-1 and T106-2. The optimized conditions for synthesis of the sulfonates S3, S4, and S6 were explored by using different mass ratios of methanol, water and the type of copromoters. It was found out that the appropriate conditions for synthesis of the sulfonate S3 included a methanol to M(M is the total mass of alkylbenzene sulfonic acid and base oil) mass ratio of 16%, a water to M mass ratio of 4%, and a copromoter A to M mass ratio of 2%; the appropriate conditions for synthesis of the sulfonate S4 included a methanol to M mass ratio of 24%, a water to M mass ratio of 2%, a copromoter B to M mass ratio of 2%; and the optimized conditions for synthesis of the sulfonate S6 included a methanol/ M mass ratio of 8%, a water/M mass ratio of 4% and a copromoter B/M mass ratio of 2%. The new sulfonates S3, S4, and S6 produced under the optimized conditions exhibited higher TBN and better antiwear property in camparison with the previous products. Grease samples G9, G10, and G11 were prepared with new sulfonates S3, S4, and S6 successfully and exhibited improved water stability and high temperature performance.

Preparation and Characterization of Ferromagnetic Calcium Alginate Complex Gel

Fe3O4 suspension, derived from chemical coprecipitation and subsequent ultrasonic treatment, was embedded into calcium alginate to form complex gel. Both gel beads and injectable gel floc were obtained by slightly tailoring the preparation condition. SEM analysis showed that the iron oxide was dispersed homogenously in nanometer. TGA profiles revealed that the content of Fe3O4 in beads was about 7.2%.

pH-Potentiometric Study on Rare Earths and Calcium Binary and Ternary Complexes with DL-Malic Acid and L-Hydroxyproline

The stability constants of ML binary system and MLL′(M=La^3+～Yb^3+, Y^3+ and Ca^2+; L=DLmalic aicd, L′=Lhydroxyproline) ternary system were determined by pHpotentiometric method under the simulating physiological condition(37 ℃, I=015 mol/L NaCl). The complex species MpLqL′rHs(abbr as pqrs) in the sytems were ascertained by program COMPLEX. The results show that there are three species(1101, 1100 and 1200) in ML binary system and one species(1010) in ML′ binary system. In addition to the above four species, a new species, 1112 was found in the MLL′-ternary system, which is the only species of mixed ligands. Rare earth ions form more stable complexes than calcium ion does and the stability differences between their complexes in the ternary system are less than that in the binary system. The distributions of all the species in LaLL′-ternary system vs pH are discussed.

Decreased Expression of Vitamin K Epoxide Reductase Complex Subunit 1 in Kidney of Patients with Calcium Oxalate Urolithiasis

Urinary prothrombin fragment 1 （UPTFl） is a potent inhibitor of urinary stone formation. UPTF1 exerts such inhibitory effect by effective 7-carboxylation in which vitamin K epoxide reductase complex subunit 1 （VKORC1）, the rate-limiting enzyme, is involved. This study examined the correlation between VKORC1 expression and calcium oxalate urolithiasis. The renal cortex samples were obtained from patients undergoing nephrectomy and then divided into 3 groups： urolithiasis group, control group A [hydronephrosis-without-stone （HWS） group], control group B （normal control group）, The localization and expression of VKORC1 in renal tissues were determined by using immunohistochemistry, immunofluorescence microscopy, Western blotting and SYBR Green I real-time reverse-transcription PCR. The rapid amplification of cDNA ends （RACE） were conducted to obtain the 3＇- and 5＇-untranslated region （UTR） of VKORC1. The results showed that VKORC1 was located in the cytoplasm of renal tubular epithelial cells. The expression of VKORC1 in the uro- lithiasis group was significantly lower than that in the other two control groups （P〈0.05）. Moreover, the 3＇- and 5＇-UTR sequence of the VKORC1 gene was successfully cloned. No insertion or deletion was found in the 3＇- and 5＇-UTR. However, a 171-bp new base sequence was discovered in the up- stream of 5＇-UTR end in the urolithiasis group. It was concluded that the decreased expression of VKORC 1 may contribute to the development of calcium oxalate urolithiasis in the kidney.

仿生再矿化治疗在牙釉质早期脱矿的作用及机制

背景:随着饮食改善和生活水平提高,酸性饮食和正畸治疗等成为导致牙釉质表面脱矿的主要原因。作为牙齿龋坏的第一步,牙釉质脱矿应被积极干预,机械磨除损伤较大且不符合微创医学理念,仿生再矿化是目前应对牙釉质脱矿的最佳方式。目的:通过对牙釉质早期脱矿的仿生再矿化治疗机制、应用方式及研究进展进行综述,为进一步攻克仿生再矿化热点难题提供思路。方法:以“Enamel demineralization,Biomimetic remineralization,amelogenin,Amorphous calcium phosphate”等作为英文关键词在PubMed数据库检索,以“釉质脱矿,仿生再矿化,釉原蛋白”等关键词在中国知网数据库进行检索,通过筛选最终共得到72篇文献进行综述分析。结果与结论:①目前针对釉质脱矿有药物治疗如含氟制剂等、激光治疗、树脂渗透、再矿化治疗等治疗方式,仿生再矿化是目前牙釉质早期脱矿最理想的修复方式。②狭义的釉质再矿化指早期釉质脱矿后内部的矿物质再沉积,广义的釉质再矿化包括釉质表面和内部两方面的矿化沉积。③临床仿生再矿化试剂多以釉原蛋白、非釉原蛋白、釉原蛋白肽、酪蛋白磷酸肽-不定形磷酸钙复合物等为主要成分。蛋白及肽类材料优势在于符合生理机制,可通过诱导定向生成高强度再矿化材料,劣势在于制作工艺相对复杂,成本较高;不定形磷酸钙复合物再矿化效果好,但需与其他材料结合使用以发挥作用;其他磷酸钙材料便于携带、有利美观,但易导致牙石形成。④未来研究应着重于以下几个方面:增加随机对照试验数据和临床结果,明确各个方式的适应证;发掘更多仿生再矿化方法,寻找合适替代材料;寻找合理的材料结合方式,以使其优缺点互补;加强临床应用便携性,以增加日常使用频率,使短期实验结论获得长期临床数据支持。

Chitosan Oligosaccharide-Ca Complex Accelerates the Depuration of Cadmium from Chlamys ferrari

This study investigated the effect of a chitosan oligosaccharide-Ca complex (COS-Ca) on the depuration of cadmium (Cd) from Chlamys ferrari. After exposure to 0.5 mg L-1 CdCl2 for 3 or 7 d, the scallops were treated by COS-Ca prior to determina-tion of Cd, calcium (Ca) and zinc (Zn) contents, Cd distribution in organs, malondialdehyde (MDA) content and antioxidant variables. Results showed that COS-Ca reduced Cd content in the viscera of the scallops, with highest Cd depuration rate (47%) observed on day 3. The COS-Ca concentration substantially affected Cd depuration, and the exposure to 8.75 mg L-1 COS-Ca led to significantly higher Cd depuration rate compared with those of lower COS-Ca concentrations (1.75, 3.5, 5.25, and 7.00 mg L-1). Distribution analysis of Cd in scallop organs indicated that COS-Ca significantly reduced Cd content in the kidney throughout the 5-d experiment, as well as in the gill during the early stage of Cd depuration. In addition, COS-Ca treatment decreased glutathione peroxidase (GSH-Px) activity and MDA content while increasing superoxide dismutase (SOD) and catalase (CAT) activities on different days. Our work suggested COS-Ca complex treatment as an effective method for acceleration of Cd depuration from Cd-contaminated bivalves.

Influence of Surfactant-polymer Complexes on Crystallization and Aggregation of CaCO_3

Hollow calcium carbonate（CaCO3） microspheres with different morphologies were synthesized via the precipitation reaction of calcium chloride with sodium carbonate in the presence of different surfactant-polymer complexes.The selected anionic surfactants were sodium dodecyl sulfonate（SDS） and sodium dodecyl benzenesulfonate（SDBS）,respectively.The selected water-soluble polymers were polyacrylic acid（PAA） and polyvinyl pyrrolidone（PVP）.In this work,SDS-PVP ＂pearl-necklace model＂ micellar complex was formed via hydrophobic effectiveness between SDS and PVP and it served as the spherical template to generate spherical CaCO3 aggregates with hollow microspheres composed of about 500 nm irregular shaped particles.SDS-PAA complexes and SDBS-PAA complexes formed ＂core-shell model＂ aggregates with calcium ions serving as the medium to link the anionic surfactant and the polymer.SDS-PAA ＂core-shell model＂ aggregates would act as templates for hollow CaCO3 microspheres consisting of 30―50nm irregular shaped crystallites.SDBS-PAA ＂core-shell model＂ aggregates served as the spherical aggregate templates to generate spherical CaCO3 aggregates consisted of many small spherical particles which had grown together.All the obtained CaCO3 hollow microspheres are calcite particles.This research may provide new insight into the control of morphologies of hollow CaCO3 microspheres in the presence of surfactantpolymer complexes.

Efficient Thermal Stabilization of Polyvinyl Chloride with Tannin-Ca Complex as Bio-Based Thermal Stabilizer

The potential use of tannin-Ca complex derived from tannins as bio-based thermal stabilizer and antioxidant additive for polyvinyl chloride (PVC) was investigated in this work. For this project, Reapak B-NT/7060 was applied as reference thermal stabilizer. Variable compositions: (1, 2, and 3) part per hundred ratio (phr) of tannin-Ca complex in the presence of 10 phr Dioctyl phthalate (DOP) as plasticizer in all PVC formulations were prepared by melt mixing by internal mixer at 165°C. Tannin-Ca complex was characterized by FT-IR spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) analysis as well as by means of differential scanning calorimetry (DSC). The tannin derivative stabilization efficiency under inert atmosphere was determined by using thermogravimetric analysis (TGA). In addition, its thermal stabilization effect has been assessed in air as oxidizing atmosphere by DSC in dynamic conditions. According to TGA thermograms, the initial degradation temperature (Ti) and optimum degradation temperature (Top?) for the main degradation stage of PVC stabilized with this derivative were about 280°C and 310°C, respectively. While these were about 255°C and 293°C, respectively for PVC stabilized with commercial thermal stabilizer. Global results of TGA, DSC, SEM and EDX show that the tannin-Ca complex provides the best properties and results in stabilizing both against thermal degradation and thermal oxidation degradation of PVC.

Involvement of VKORC1 in the Inhibition of Calcium Oxalate Crystal Formation in HK-2 Cells

Summary： The vitamin K epoxide reductase complex subunit 1 （VKORC1）, the rate-limiting enzyme for vitamin K recycling, is significantly down-regulated in the kidneys of urolithiasis patients. This study searched for direct evidence to define the inhibitory activity of VKORC1 against calcium oxalate （CaOx） crystal formation. In the experiment of VKORC1 overexpression, HK-2 cells were transfected with the pFLAG-CMV-7.1-VKORC1 plasmid as a pFLAG-CMV-7.1-VKORC1 transfection group or the pFLAG-CMV-7.1 plasmid as a pFLAG-CMV-7.1 control group. In the experiment of VKORC1 knockdown, HK-2 cells were transfected with the PGPU6/GFP/Neo-VKORClshRNA-2 as a PGPU6/GFP/Neo-VKORClshRNA-2 transfection group or the PGPU6/GFP/Neo-shRNA-NC plasmid as a PGPU6/GFP/Neo-shRNA-NC control group. The expression of VKORC1 in HK-2 cells was detected by real-time quantitative PCR and Western blotting. The CaOx crystal formation was observed under the laser-scanning confocal microscope. It was found that the expression levels of VKORC1 mRNA and protein were significantly higher in the pFLAG-CMV-7.1-VKORC 1 transfection group than in the pFLAG-CMV-7.1 control group （P〈0.01）. The number of CaOx crystals in HK-2 cells incubated in fluorescently labeled CaOx monohydrate （COM） crystal medium for 48 h was 14±4 per field （100×） in the pFLAG-CMV-7.1-VKORC1 transfection group and 26±5 per field （100×） in the pFLAG-CMV-7.1 control group respectively under the laser-scanning confocal microscope. The amount of CaOx crystal aggregation and formation in the pFLAG-CMV-7.1-VKORC 1 transfection group was significantly reduced as compared with the pFLAG-CMV-7.1 control group （P〈0.05）. The expression levels of VKORC 1 mRNA and protein were significantly lower in the PGPU6/GFP/Neo-VKORC 1 shRNA-2 transfection group than in the PGPU6/GFP/Neo-shRNA-NC control group （P〈0.05）. The number of CaOx crystals in HK-2 cells incubated in fluorescently labeled COM crystal medium was 65±11 per field （100x） in the PGPU6/GFP/Neo-VKORC 1 shRNA-2 transfection group and 24±6 per field （100×） in the PGPU6/GFP/Neo-shRNA-NC control group respectively under the laser-scanning confocal microscope. The amount of CaOx crystal aggregation and formation in the PGPU6/GFP/Neo-VKORClshRNA-2 transfection group was significantly increased as compared with the PGPU6/GFP/Neo-shRNA-NC control group （P〈0.05）. These findings suggested that the VKORC 1 protein could inhibit CaOx salt crystallization, adhesion and aggregation. This research would help us to understand the mechanisms involving the interaction between crystallization and epithelial cells and the formation of CaOx. Key words： calcium oxalate crystals; kidney stone; vitamin K epoxide reduetase complex subunit 1; laser-scanning confocal microscopy

动物羽毛和大豆豆粕制备复合氨基酸螯合钙的工艺研究

分别以动物羽毛和大豆豆粕为前驱体,制备复合氨基酸螯合钙,研究物料比、pH值、螯合温度、螯合时间对螯合率的影响。利用有机溶剂浸提法制备固体复合氨基酸钙螯合物,并用EDTA法滴定螯合钙的含量,对其进行红外光谱表征。结果表明,当动物羽毛复合氨基酸粉和氯化钙的摩尔比为2∶1,螯合温度为60℃,螯合时间为5.5 h,体系pH为10.5时,螯合率最高,为92.30%;当大豆豆粕复合氨基酸粉和氯化钙的物质的量之比为2.5∶1,螯合温度为60℃,螯合时间为5 h,体系pH为10.5时,螯合率最高,为83.08%。实验表明,动物羽毛复合氨基酸更易与钙元素螯合。

酶化石复合菌粉抑制大鼠肾结石形成及对肾功能的保护作用

目的探讨酶化石复合菌粉抑制大鼠肾脏草酸钙结石形成及对肾功能的保护作用。方法选用24只SPF级、10周龄雄性大鼠,随机分为对照组(正常饮水和饲料,n=6)、模型组(1%乙二醇饮水,n=6)、枸橼酸氢钾钠治疗组(1%乙二醇饮水+枸橼酸氢钾钠0.9 g/kg灌胃,n=6)和酶化石复合菌粉治疗组(1%乙二醇饮水酶化石复合菌粉0.4 g/kg灌胃,n=6)。全自动生化分析仪检测第0、28天血清中的尿素、肌酐和Ca^(2+)浓度,以及尿液中的草酸、Ca^(2+)浓度;采用HE染色观察肾脏组织病理情况,免疫组化检测肾组织中NF-κB p65、STAT3、TNF-α、IL-1β表达;采用ELISA检测大鼠血清丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)指标。结果HE染色结果证实模型组肾小管管腔内充满草酸钙结晶;与模型组比较,酶化石复合菌粉治疗组和枸橼酸氢钾钠组肾小管草酸钙结晶大量减少。第0天尿液Ca^(2+)和草酸及血清中的尿素、肌酐、Ca^(2+)在各组之间无显著性差异。对照组相比,模型组第28天尿液Ca^(2+)、草酸及血清中的尿素、肌酐显著升高(P<0.05);与模型组比较,酶化石复合菌粉治疗组、枸橼酸氢钾钠组的尿液Ca^(2+)、草酸及血清中的尿素、肌酐均下降(P<0.05)。与对照组比较,模型组血清CAT、GSH-Px和SOD指标水平下降,而MDA指标水平升高(P<0.05);与模型组比较,酶化石复合菌粉治疗组和枸橼酸氢钾钠组中CAT、GSH-Px和SOD指标水平升高,而MDA指标下降(P<0.05)。与对照组比较,模型组肾脏NF-κB p65、STAT3、TNF-α、IL-1β在组织中的表达上升(P<0.05);与模型组比较,酶化石复合菌粉治疗组和枸橼酸氢钾钠组中NF-κB p65、STAT3、TNF-α、IL-1β表达降低(P<0.05)。结论酶化石复合菌粉能够降低尿草酸、Ca^(2+)含量,增强抗氧化应激,具有抑制肾结石形成及对肾功能的保护作用。

球形纳米碳酸钙制备方法的研究进展

作为一种特定形貌的碳酸钙产品,球形碳酸钙(CaCO_(3))具有比表面积大、密度小、分散性和平滑性良好等特点,在涂料、造纸、胶黏剂、塑料、油墨、化妆品、药物缓控释等领域均得到广泛应用,球形CaCO_(3)的制备方法成为国内外的研究重点,受到越来越多的关注。本文介绍了近年来球形纳米CaCO_(3)的制备方法及研究进展,旨在为工业制备球形纳米CaCO_(3)提供参考。

糖醇螯合钙对茄子生长、产量和品质的影响

通过田间试验探讨了糖醇螯合钙对茄子生长发育、产量和品质的影响。试验结果表明,施用糖醇螯合钙处理的茄子株高和茎粗较常规施肥处理分别提高4.60%和18.18%,叶长和叶宽均显著增加。糖醇螯合钙提高了茄子产量,较常规施肥和喷施硝酸钙处理分别增产9.11%和2.24%,经济效益明显提高;同时改善了茄子品质,VC含量、可溶性固形物含量和糖酸比较常规施肥处理分别提高85.38%、34.55%和49.51%;较喷施硝酸钙处理分别提高37.23%、3.60%和26.64%。

复合氨基酸螯合钙对大鼠生物利用率的研究

以Wister大鼠为模型,利用钙存留率等指标有效检验了复合氨基酸螯合钙与两种市售补钙制剂的生物利用率。结果表明,复合氨基酸螯合钙组钙存留率极显著高于葡萄糖酸钙组和碳酸钙组,股骨钙和储留钙与葡萄糖酸钙组相当,高于碳酸钙组,但其表观吸收率无显著差异。由此可见,复合氨基酸螯合钙生物利用率优于某碳酸钙制剂,与某葡萄糖酸钙制剂相当。

高碱值磺酸钙对润滑脂性能的影响

高碱值磺酸盐是生产复合磺酸钙基润滑脂的重要原料,其质量是决定复合磺酸钙基润滑脂产品品质的关键因素之一。为选择合适的高碱值磺酸盐,考察不同高碱值磺酸盐从无定型碳酸钙转化为方解石型碳酸钙的转相时间、稠化能力,以及不同高碱值磺酸盐制备的润滑脂的滴点、锥入度、钢网分油和滚筒安定性能;筛选出的高碱值磺酸盐制备的复合磺酸钙基润滑脂具有优异的高温特性、胶体安定性和机械安定性等,为高端复合磺酸钙基润滑脂的研发和工业生产奠定基础。