Friction and wear performances of borates and lanthanum chloride in water

The antiwear and friction-reducing performances of sodium borate, potassium borate and lanthanum chloride in water were evaluated on a four-ball friction tester. The topographies, element distribution and chemical characteristics of the worn surfaces were investigated by scanning electron microscope （SEM）, energy dispersion of X-ray （EDX） and X-ray photoelectron spectroscope （XPS）. The results indicated that sodium borate, potassium borate and lanthanum chloride increased extreme pressure, antiwear and friction-reducing capacities of water to a certain extent, of which potassium borate was the best candidate. Combination of lanthanum chloride with sodium borate and po- tassium borate respectively further improved antiwear and friction-reducing capacities. Scratches of worn surfaces lubricated with water containing borates and lanthanum chloride were less severe than those lubricated with water containing borates alone. A tribochemical film mainly composed of oxides of lanthanum, boron and iron reduced friction and wear for water lubricant formulated with both borates and lanthanum chloride.

Lanthanum Chloride Inhibiting Expression of Inducible Nitric Oxide Synthase in RAW264.7 Macrophages Induced by Lipopolysaccharide

Nitric oxide（NO）and its reaction products were key players in the pathophysiology of sepsis and shock.The present study was designed to explore the effects of lanthanum chloride（LaCl3）on inducible nitric oxide synthase（iNOS）expression,at both gene and protein levels,in RAW264.7 macrophages induced by Lipopolysaccharide（LPS）.Reverse transcription polymerase chain reaction（RT-PCR）,immunofluorescence,and western blot were employed to measure iNOS gene expression,localization,and protein expression respectively.NO production in culture supernatants was detected by the nitrate reductase method.The results showed that LaCl3 significantly attenuated the iNOS gene and protein expression,as well as NO production in RAW264.7cells induced by LPS.

Reaction Kinetics of LiOH·H_2O and CO_2 Improved with Composite Silica Gel of Lanthanum Chloride

Reaction kinetics of LiOH·H2O and CO2 within a closed system were studied under the adsorption of water vapor by composite silica gel of lanthanum chloride. At the reaction temperature of 273～323 K and initial CO2 pressures of 40～100 kPa, reaction kinetics obeyed the Erofeev model. The reaction rate decreased slightly while the initial CO2 pressure reduced. When the reaction occurred at 273～299 K, the reaction rate was so low that it was almost independent of the reaction temperature. However, as the temperature rose up to 300～323 K, LiOH·H2O dehydrated its crystal water, and both the dehydrated and reaction-generated water were evaporated from solid reactant. For the dehydration rate increased, the reaction rate also increased as the reaction temperature rose. While the temperature was higher than 323 K, the reaction apparent activation energy of LiOH·H2O and CO2, was higher than 52.5 kJ·mol-1 and close to 61.4 kJ·mol-1 of the LiOH·H2O dehydrated enthalpy variable at 298 K, in which anhydrous LiOH was the major reactant and showed the reaction characteristics of LiOH crystals.

Reaction Kinetics of LiOH Improved with Composite Silica Gel of Lanthanum Chloride for Absorbing CO_2

A static method was employed to study the reaction kinetics of anhydrous lithium hydroxide (LiOH) and CO2. The reaction generated water was absorbed with the composite silica gel of lanthanum chloride to make the experiment repeatable. At the reaction temperature of 15～60 ℃ and initial CO2 pressures of 25～100 kPa, the reaction rate of anhydrous LiOH and CO2 decreased slightly with the reduction of initial CO2 pressure and the rise of reaction temperature, indicating that the reaction activation energy of LiOH and CO2 was negative and close to zero. During the middle period (1～5 min) of the isothermal reaction, the ratio of reaction efficiency was approximately the power of 0.4 to that of initial CO2 pressures. As anhydrous LiOH reacted to CO2, the solid product Li2CO3 covered on the surface of LiOH was not compact, so it did not hinder the subsequent reaction of absorbing the CO2 gas. The reaction kinetics of anhydrous LiOH and CO2 obeyed the Erofeev′s model.

Comparison of toxicity between lanthanum oxide nanoparticles and lanthanum chloride

Due to the wide application of rare earth elements,lanthanum(La) is gradually accumulated in our living environment.Lanthanum can enter the body through a variety of routes,which has a series of effects on various systems.As a consequence,the safety of lanthanum deserves our attention.This study aims to compare the toxicity of lanthanum oxide nanoparticles(La_(2)O_(3) NPs) and lanthanum chloride(LaCl_(3)) and enrich the toxicity evaluation of lanthanum.Therefore,a 30 d intragastal experiment was conducted.C57BL/6j mice were given by La_(2)O_(3) NPs solution and LaCl_(3) solution respectively at doses of 0,30,60 and120 mg/kg BW(lanthanum content).The results show that,compared with the control group,both La_(2)O_(3)NPs and LaCl_(3) can reduce the body weight of female mice in the high-dose group,but for male mice,the high-dose La_(2)O_(3) NPs solution can increase the body weight,while LaCl_(3) has the opposite effect.The coefficients of liver,kidney,heart,lung,uterine and ovaries increase first and then decrease with the exposure dose,but testes and epididymides coefficient keep increasing with the exposure of LaCl_(3) and La_(2)O_(3) NPs.La_(2)O_(3) NPs and LaCl_(3) can reduce the concentration of triglycerides(TG) and increase the level of low density lipoprotein(LDL),but the effect of La_(2)O_(3) NPs is more obvious.La_(2)O_(3) NPs and LaCl_(3) can reduce the concentration of malondialdehyde(MDA),increase the total antioxidant capacity(T-AOC)and enhance the activity of catalase(CAT),but LaCl_(3) has more obvious protective effects on oxidative stress.La_(2)O_(3) NPs and LaCl_(3) have potential risks to liver,and the toxicity of La_(2)O_(3) NPs might be higher than that of LaCl_(3).

Inhibitory effect of lanthanum chloride on migration and invasion of cervical cancer cells

Tumor metastasis remains the main reason for treatment Jhilure and death of patients with cervical cancer. The prcsent study was designed to explore the effects of lanthanum chloride （LaCl3 on the invasion and migration of cervical cancel- cells and the underlying mechanisms. The migration and invasion of tumor cells was evaluated by a modified Transwell/Boyden chamber assays. It is well known that MMPs （Matrix metalloproteinases） and NF-κB （Nuclear factor-κB） pathway play important roles in migration and invasion of tumor cells, and also the expression of MMPs were regulated by NF-κB signaling. The expression on MMP-1 and MMP-9 was detected by reverse transcription polymerase chain reaction （RT-PCR）; Western blot and the NF-KB-DNA-binding ac tivity assay were used to analyze the NF-KB activity. The results indicated that LaCl3 was capable of inhibiting the cell invasion and migration of human cervical cancer Hela cells by decreasing the expression of MMP-1 and MMP-9 via blocking NF-κB pathway

Dose-dependent effects of lanthanum chloride on wear particle-induced aseptic inflammation in a murine air-pouch model

To investigate the effects of local injection of different doses of lanthanum chloride （LaCl3） on aseptic inflammation in mice stimulated by wear particles from artificial joints, the particles were prepared by vacuum ball mill in vitro and air-pouch models were performed with 45 male BALB/c mice that were randomly divided into blank control group, wear particle group and wear parti- cle ＋ LaCl3 （0.1, 0.9 and 8.1 μmol） group. All animals were sacrificed and tissue specimens were harvested 7 days after treatment. Hematoxylin and eosin （H＆E） staining, enzyme-linked immunosorbent assay （ELISA）, reverse transcription-polymerase chain reac- tion （RT-PCR） and western blot were applied to observe inflammatory reaction and detect the expression of pro-inflammatory cyto- kines （TNF-et, IL-1β） and nuclear factor-κB （NF-κB） in mRNA and protein levels in air-pouch membrances. The results showed that wear particles could stimulate aseptic inflammation in vivo effectively; 0.9 μmol LaCl3 could significantly inhibit wear parti- cle-induced gene and protein expression of pro-inflammatory cytokines and NF-Id3 （P〈0.05）; 0.1 and 8. 1 μmol LaCl3 did not exert an inflammation-inhibiting effect and even caused adverse effects at 8.1 μmol. In conclusion, LaC13 played a protective role against wear particle-induced aseptic inflammation dose-dependently, which was involved in NF-κB related signaling pathways.

Lanthanum chloride or citrate is absorbed mainly via M cells in gastrointestinal tracts with lanthanum phosphates as the transformed species

In the present study, we investigated the transformed species and the absorptive mechanism of rare earth elements（REEs） in gastrointestinal（GI） tract, using La Cl3 and La Cit as representative compounds. Artificial gastric and intestinal fluids were used to simulate the environment of the digestive tract in vivo. The inductively coupled plasma mass spectrometry（ICP-MS） result showed that more than 99.9% of La Cl3 and La Cit formed precipitation in artificial intestinal fluid, with the average size distribution of 200 nm（2-h incubation） increasing to 600 nm（24-h incubation） determined by dynamic light scattering（DLS）, indicating the aggregation of the particles. The Fourier transform infrared spectroscopy（FTIR） analysis demonstrated that the constituents of these particles were mainly in the form of lanthanum phosphates. To explore the transport mechanism of REEs in GI tract, the mice Peyer＇s patches（PPs） and intestinal epithelium were separated to evaluate the content of lanthanum by ICP-MS following oral administration with 2 or 100 mg/kg/day of La Cit for 7 d. The results showed that the amount of lanthanum phosphate particles absorbed by PPs was significantly greater than that of intestinal epithelium, indicating that lanthanum particles might be phagocytosed mainly by M cells located in the follicle-associated epithelium（FAE） overlying PPs. Furthermore, Caco-2 cell monoculture and Caco-2/Raji B cell coculture models were established to simulate intestinal epithelial cells and FAE, respectively. The result showed that the transport of lanthanum in Caco-2/Raji B coculture model was significantly higher than that in Caco-2 monoculture model（about 60 times higher）, and the level of lanthanum in the basal compartment of Caco-2 monoculture model was very low, supporting that M cells were the main route for lanthanum phosphate particles to be transported and absorbed. Taken together, these data suggested that La Cl3 and La Cit in GI tract were absorbed mainly via M cells with lanthanum phosphates as transformed species. The obtained results would provide the theoretical basis for the rational application of REEs in agriculture and medicine.

Wear particle-mediated expressions of pro-inflammatory cytokines, NF-κB and RANK were impacted by lanthanum chloride in RAW264.7 cells

To explore the impact of different concentrations of lanthanum chloride （LaC13） on critical components of wear particle-mediated signaling pathways in inflammation and osteoclastogenesis, RAW264.7 cells were naturally divided into eight groups and analyzed by CCK-8 assay, flow cytometry, ELISA, RT-PCR and western blot after treatments. The results showed that three concentrations of LaCI3 had no influence on viability of RAW264.7 cells and down-regulated receptor activator of nuclear factor rd3 （RANK） instead of macrophage colony-stimulating factor receptor （M-CSFR）. Additionally, 2.5 and 10 pmol/L LaC13 could signifi- cantly inhibit gene and protein levels of pro-inflammatory cytokines （tumor necrosis factor-or and interleukin-113, i.e., TNF-ct and IL-113） and NF-r,B/p65, but 100 pmol/L LaC13 did not exert an obvious inflammation-inhibiting effect, and even induced inflamma- tion. In conclusion, these findings demonstrated that LaC13 was able to suppress wear particle-induced inflammation and activation of NF-rd3 in a certain range of concentrations in vitro and mainly decrease the expression of RANK, but not M-CSFR, all of which were generally recognized to play a pivotal role in osteoclastogenesis.

Effect of lanthanum chloride on growth of breast cancer cellsand regulation of c-met transcription

Lanthanum salt is a prescription drug,but its underlying functions and mechanisms are not fully under-stood currently.To explore the potential therapeutic value of lanthanum chloride,cytotoxicity test was applied to investigate its effects on cell proliferation.Furthermore,we observed its influence on pro-oncogene c-met by reverse transcription polymerase chain reaction(RT-PCR).In MCF-7 cell line,lanthanum chloride repressed cell proliferation at high concentrations but had no significant inhibition effect on cell growth at low concentrations.However,we observed that lanthanum chloride repressed c-met transcription at a low concentration.This may suggest that lanthanum chloride is a potent drug to inhibit the high expression of c-met in carcinoma cells and play a clue for inhibiting the growth and invasion of tumor.

Studies on Solvent System of Cesium Chloride and Lanthanum Chloride and Synthesization of Four Types of New Compounds

This article describes the solubility data of the quaternary systems of CsCl LaCl 3 HCl H 2O(25 ℃, HCl 13% or 23%(wt)) and CsCl LaCl 3 HAc H 2O(30 ℃, HAc 42%(wt)), and the corresponding solubility equilibrium diagrams. Three new compounds, CsCl·LaCl 3·4H 2O, 2CsCl·LaCl 3·2H 2O and 3CsCl·LaCl 3·3H 2O have been found. From analysis of the systems by the X ray powder diffraction, TG DTG and DTA, the properties of the compounds are presented. The interpretation of the mechanism of Meyer′s reactions is discussed further and the synthesis method of four type new compounds is offered.

Effect of Lanthanum and Cerium on Expression of RSCU-PA-32k Gene in Saccharomyces Cerevisiae

Lanthanum chloride can promote expression efficiency of rscu-PA-32k gene in yeast. 2 and 5 mmol·L -1 LaCl 3 increase the activities of the expression product by 13% and 20% (from 14.6 to 16.5 and 17.5 U·ml -1). Cerium chloride can decrease the activity of expression product. 2 and 5 mmol·L -1 CeCl 3 decreases the activities of the expression product by 21% and 33% (from 14.6 to 11.5 and 9.8 U·ml -1).

Electrode process of La(Ⅲ) in molten LiCl-KCl

The electrode process of La(Ⅲ) at Mo electrode in the molten LiCl-KCl for temperatures ranging from 683 K to 773 K was studied by cyclic voltammetry and chronopotentiometry,respectively.The results showed that in the molten LiCl-KCl,reduction of La(Ⅲ) occurred in a step with a global exchange of three electrons.Cyclic voltammetry studies indicated that at a sweep rate lower than 0.2 V/s,the electroreduction of La(Ⅲ) to lanthanum metal was reversible and controlled by diffusion of La(Ⅲ).However,the process b...

Phase Equilibrium of Ternary Systems LaX_3-C_(18)H_(16)N_3O_2Cl-H_2O

Solubilities and refractive indices of saturated solutions of the ternary systems LaX 3 C 18 H 16 N 3O 2Cl(4 ( p chlorobenzoyl) aminoantipyrine H 2O(30 ℃; X=NO 3 -, Cl -) were determined. The incongruent compound, LaL 3(NO 3) 3 was discovered in the system LaL 3(NO 3) 3 L H 2O, while LaCl 3 L H 2O(L=4 ( p chlorobenzoyl) aminoantipyrine H 2O) is a simple eutonic system.

Effects of lanthanum on POD expression and DNA methylation of purple pepper under salt stress

Pepper seedlings were hydroponically cultivated in 0-20 mg/L extraneous lanthanum chloride （La3＋） for different numbers of days to investigate its regulating effects under salt stress. The results showed that, depending on the salt stress of 0.75 g/L, a lower concentration of La3＋ （1.0 rag/L） might result in the lowest death rate, increase POD activity and change the band type of the stem and root on the 8th day. Furthermore, a methylation analysis by the methylation-sensitive amplified polymorphism （MSAP） technique indicated that a lower concentration of La3＋ （1.0 mg/L） triggered the lowest methylation level of 26.1%, of which the hypermethylation events were the primary type of methylation. In addition, the sequencing of 14 differ- entially expressed polymorphic fragments and the subsequent blast search revealed that La3＋ could induce methylation events in salt-tolerance sequences.

Lanthanum Inhibited the Binding of LPS with Monocyte and CD 14 Expression Upregulation

To investigate the effects of lanthanum chloride on binding of LPS to monocyte and CD14 expression upregulation induced by LPS,human monocytes were analyzed by flow cytometry(FCM).The results indicated that lanthanum chloride could decrease the binding rate of LPS with monocyte significantly.LPS upregulated the expression of CD14 on monocyte in a dose dependant manner,however,lanthanum chloride could inhibit the increase of CD14 expression on monocytes by halves.Cellular & Molecular Immunology. 2004;1(5):392-394.

Influence of LaCl_3 addition on microstructure and properties of nickel-electroplating coating

The influence of rare earth chloride LaCl3 ·7H2O addition on the microstructural features, phase structure, corrosion resistance and microhardness of nickel-electroplating was investigated. The Watts-type with different additive amounts of LaCl3·7H2O（0-1.2g/L） were used in the experiment. Surface morphologies of coatings were examined by scanning electronic microscopy （SEM）, transmission electronic microscopy （TEM） was used to measure the coatings＇ grain size and the microstructure of coatings was detected by X-ray diffraction （XRD）. Corrosive investigation was carried out in 3.5 wt.% NaCl solution. The microhardness values of the coatings with different amounts of LaCl 3·7H2O were measured, and the mechanism of the variation in microhardness was studied. Results showed that the addition of rare earth lanthanum refined the grain size and improved the surface consistency of the coatings, meanwhile the microhardness and corrosion property of coatings were improved and achieved a maximum with arround 1.0g/L LaCl 3·7H2O addition in electrolyte. The preferred growth orientation of lanthanum doped coating was crystal face （200）, meanwhile the La2 Ni7 phase was detected in the nickel coating by XRD and this was due to the induced co-deposition of elements La and Ni. The reason maybe was that the special out-layer electronic structure of element La raised the polarization of Ni cathode deposition, accelerated the nucleation of Ni and reduced hydrogen evolution from cathode surface.

CoCl_2·6H_2O or LaCl_3·7H_2O Catalyzed Biginelli Reaction. One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1 H)-ones

An efficient synthesis of 3,4-dihydropyrimidinones from aldehyde, β-ketoester and urea in ethanol using cobalt chloride hexahydrate or lanthanum chloride heptahydrate as acatalyst was described. Compared to the classical Biginelli reaction, this new method consistentlyhas the advantage of good yields (56%―99%) as well as short reaction tune (4―5 h).

Effects of CeCl_3 and LaCl_3 on callus and root induction and the physical response of tobacco tissue culture

La3＋ and Ce3＋ have positive effects on plant growth and production. Although it is well known that rare earth elements promote cell growth. The biological effects of La^（3＋） and Ce^（3＋） on callus, shoot and root induction in tobacco are still unclear. The relationships among callus induction, rooting, enzyme activities and stomatal characteristics in tobacco are unknown. The objectives of this study were to identify the relationships between the induction of calluses, shoots, roots, stomata and enzyme activities. The induction percentages of calluses, buds, roots were recorded at 5,10,15, 20 and 25 days after La^（3＋） and Ce^（3＋） treatments. Peroxidase isoenzyme activity was determined by electrophoresis. The characteristics of the stomata were observed under an optical microscope. Our results show that low concentrations of Ce^（3＋）（〈15 mg/L） result in increases in the induction percentages of calluses,buds and roots, but La^（3＋）（〉5 mg/L） inhibits the induction of calluses, buds and roots. There are more peroxidase isoenzyme bands in Ce^（3＋） treatments than in La^（3＋） treatments. This is consistent with the induction percentages of calluses,buds and roots in Ce^（3＋） and La^（3＋） treatments. High enzyme activities may promote the induction of calluses, buds and roots. The stomata area and stomata number of leaves are significantly different between La^（3＋） treatments and Ce^（3＋） treatments. La^（3＋） improves the stomata area and number. Based on these results, we speculate that La^（3＋） may promote the development of the photosynthetic system. Ce^（3＋）may promote tobacco growth and rooting by improving enzyme activities.