Lactate:a prospective target for therapeutic intervention in psychiatric disease

Although antipsychotics that act via monoaminergic neurotransmitter modulation have considera ble therapeutic effect,they cannot completely relieve clinical symptoms in patients suffering from psychiatric disorde rs.This may be attributed to the limited range of neurotransmitters that are regulated by psychotropic drugs.Recent findings indicate the need for investigation of psychotropic medications that target less-studied neurotransmitte rs.Among these candidate neurotransmitters,lactate is developing from being a waste metabolite to a glial-neuronal signaling molecule in recent years.Previous studies have suggested that cerebral lactate levels change considerably in numerous psychiatric illnesses;animal experiments have also shown that the supply of exogenous la ctate exerts an antidepressant effect.In this review,we have described how medications targeting newer neurotransmitte rs offer promise in psychiatric diseases;we have also summarized the advances in the use of lactate(and its corresponding signaling pathways)as a signaling molecule.In addition,we have described the alterations in brain lactate levels in depression,anxiety,bipolar disorder,and schizophrenia and have indicated the challenges that need to be overcome before brain lactate can be used as a therapeutic target in psychopharmacology.

Lactate metabolism in neurodegenerative diseases

Lactate,a byproduct of glycolysis,was thought to be a metabolic waste until the discovery of the Warburg effect.Lactate not only functions as a metabolic substrate to provide energy but can also function as a signaling molecule to modulate cellular functions under pathophysiological conditions.The Astrocyte-Neuron Lactate Shuttle has cla rified that lactate plays a pivotal role in the central nervous system.Moreover,protein lactylation highlights the novel role of lactate in regulating transcription,cellular functions,and disease development.This review summarizes the recent advances in lactate metabolism and its role in neurodegenerative diseases,thus providing optimal pers pectives for future research.

Reversed-Phase-HPLC Assay Method for Simultaneous Estimation of Sorbitol, Sodium Lactate, and Sodium Chlorides in Pharmaceutical Formulations and Drug Solution for Infusion

A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chlorides in a drug solution for infusion. Sorbitol, Sodium lactate, and Chloride are all officially recognized in the USP monograph. Assay methods are provided through various techniques, with titrations being ineffective for trace-level quantification. Alternatively, IC, AAS, and ICP-MS, though highly accurate, are costly and often unavailable to most testing facilities. When considering methods, it’s important to prioritize both quality control requirements and user-friendly techniques. A simple HPLC simultaneous method was developed for the quantification of Chlorides, Sorbitol, and Sodium Lactate with a shorter run time. The separation utilized a Shimpack SCR-102(H) ion exclusion analytical column (7.9 mm × 300 mm, 7 μm), with a flow rate of 0.6 mL per min. The column compartment temperature was maintained at 40°C, and the injection volume was set at 10 μL, with detection at 200 nm. All measurements were conducted in a 0.1% solution of phosphoric acid. The analytical curves demonstrated linearity (r > 0.9999) in the concentration range of 0.79 to 3.8 mg per mL for Sodium Lactate (SL), 0.16 to 0.79 mg per mL for Sodium Chloride (SC), and 1.5 to 7.2 mg per mL for Sorbitol. Validation of the developed method followed the guidelines of the International Conference on Harmonization (ICH Q2B) and USP. The method exhibited precision, robustness, accuracy, and selectivity. In accelerated stability testing over 6 months, no significant variations were observed in organoleptic analysis and pH. Consequently, the developed method is deemed suitable for routine quality control analyses, enabling the simultaneous determination of Sodium Lactate, Sodium Chloride, and Sorbitol in pharmaceutical formulations and infusions.

Effects of potassium lactate on sensory attributes,bacterial community succession and biogenic amines formation in Rugao ham

To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels(0%,0.5%,1%,2%)were investigated;the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated.With the increase of potassium lactate from 0%to 2%,the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed;the abundance of Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN.Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2%potassium lactate.

The use of oral human immunodeficiency virus pre-exposure prophylaxis in pregnant and lactating women in sub-Saharan Africa:considerations,barriers,and recommendations

In sub-Saharan Africa(SSA),63%of new human immunodeficiency virus(HIV)infections in 2021 were among women,particularly adolescent girls,and young women.There is a high incidence of HIV among pregnant and lactating women(PLW)in SSA.It is estimated that the risk of HIV-acquisition during pregnancy and the postpartum period more than doubles.In this article,we discuss the safety and effectiveness of drugs used for oral HIV pre-exposure prophylaxis(PrEP),considerations for initiating PrEP in PLW,the barriers to initiating and adhering to PrEP among them and suggest recommendations to address these barriers.Tenofovir/emtricitabine,the most widely used combination in SSA,is safe,clinically effective,and cost-effective among PLW.Any PLW who requests PrEP and has no medical contraindications should receive it.PrEP users who are pregnant or lactating may experience barriers to starting and adhering for a variety of reasons,including personal,pill-related,and healthcare facility-related issues.To address the barriers,we recommend an increased provision of information on PrEP to the women and the communities,increasing and/or facilitating access to PrEP among the PLW,and developing strategies to increase adherence.

Maternal dietary patterns associated with bone density in Chinese lactating women and infants at 6 months postpartum:a prospective study using data from 2018-2019

This cohort study was designed to explore the relationship between maternal dietary patterns(DPs)and bone health in Chinese lactating mothers and infants.We recruited 150 lactating women at 1-month postpartum.The estimated bone mineral density(eBMD)of subjects’calcanei and the information on dietary intake were collected.After 5-month follow-up,the eBMD of mothers and their infants were measured again.Factor analysis was applied to determine maternal DPs.General linear models were used to evaluate the association between maternal DPs and maternal eBMD loss or infants’eBMD.With all potential covariates adjusted,Factor 2(high intake of whole grains,tubers,mixed beans,soybeans and soybean products,seaweeds,and nuts)showed a positive association with the changes of maternal eBMD(β=0.16,95%CI:0.005,0.310).Factor 3(high intake of soft drinks,fried foods,and puffed foods)was inversely correlated with the changes of maternal eBMD(β=-0.22,95%CI:-0.44,0.00).The changes of maternal eBMD were positively associated with 6-month infants’eBMD(β=0.34,95%CI:0.017,0.652).In conclusion,Factor 2 might contribute to the maintenance of eBMD in lactating women,while Factor 3 could exacerbate maternal eBMD loss.Additionally,the changes of maternal eBMD presented a positive correlation with 6-month infants’eBMD.

Effects of improved amino acid balance diet on lysine mammary utilization, whole body protein turnover and muscle protein breakdown on lactating sows

Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown.Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets(10.80 MJ/kg net energy):control(CON;19.24%CP)and reduced CP with“optimal”AA profile(OPT;14.00%CP).Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1,14,18,and 21 of lactation.Between d 14 and 18,a subset of 9 sows(CON=4,OPT=5)was infused with a mixed solution of 3-[methyl-2H3]histidine(bolus injection)and[13C]bicarbonate(priming dose)first,then a constant 2-h[13C]bicarbonate infusion followed by a 6-h primed constant[1-13C]lysine infusion.Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment,Lys oxidation rate,whole body protein turnover,and muscle protein breakdown.Results Over the 21-d lactation period,compared to CON,sows fed OPT had greater litter growth rate(P<0.05).Compared to CON,sows fed OPT had greater efficiency of Lys(P<0.05),Lys mammary flux(P<0.01)and whole-body protein turnover efficiency(P<0.05).Compared to CON,sows fed OPT tended to have lower whole body protein breakdown rate(P=0.069).Muscle protein breakdown rate did not differ between OPT and CON(P=0.197).Conclusion Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown.These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.

Postpartum depression and partner support during the period of lactation:Correlation research and its influencing factors

BACKGROUND Postpartum depression(PPD)not only affects the psychological and physiological aspects of maternal health but can also affect neonatal growth and development.Partners who are in close contact with parturient women play a key role in communication and emotional support.This study explores the PPD support relationship with partners and its influencing factors,which is believed to establish psychological well-being and improve maternal partner support.AIM To explore the correlation between PPD and partner support during breastfeeding and its influencing factors.METHODS Convenience sampling was used to select lactating women(200 women)who underwent postpartum examinations at the Huzhou Maternity and Child Health Care Hospital from July 2022 to December 2022.A cross-sectional survey was conducted on the basic information(general information questionnaire),depression level[edinburgh postnatal depression scale(EPDS)],and partner support score[dyadic coping inventory(DCI)]of the selected subjects.Pearson’s correlation analysis was used to analyze the correlation between PPD and DCI in lactating women.Factors affecting PPD levels during lactation were analyzed using multiple linear regression.RESULTS The total average score of EPDS in 200 lactating women was(9.52±1.53),and the total average score of DCI was(115.78±14.90).Dividing the EPDS,the dimension scores were:emotional loss(1.91±0.52),anxiety(3.84±1.05),and depression(3.76±0.96).Each dimension of the DCI was subdivided into:Pressure communication(26.79±6.71),mutual support(39.76±9.63),negative support(24.97±6.68),agent support(6.87±1.92),and joint support(17.39±4.19).Pearson’s correlation analysis demonstrated that the total mean score and individual dimension scores of EPDS during breastfeeding were inversely correlated with the total score of partner support,stress communication,mutual support,and cosupport(P<0.05).The total mean score of the EPDS and its dimensions were positively correlated with negative support(P<0.05).Multiple linear regression analysis showed that the main factors affecting PPD during breastfeeding were marital harmony,newborn health,stress communication,mutual support,negative support,cosupport,and the total score of partner support(P<0.05).CONCLUSION PPD during breastfeeding was associated with marital harmony,newborn health,stress communication,mutual support,negative support,joint support,and the total DCI score.

Effect of care intervention with a health education form for breastfeeding on breast distension,pain,and lactation in postpartum mothers

BACKGROUND Breastfeeding not only meets the nutritional needs of newborn growth and development but also promotes uterine contraction and discharge of lochia,which helps in maternal recovery.However,some mothers experience abnormal lactation and breast swelling due to a lack of breastfeeding knowledge,painful cesarean incisions,anesthesia,negative emotions,and other factors,resulting in a reduced breastfeeding rate,which adversely affects neonatal and maternal health.AIM To explore the effects of care intervention with a health education form for breastfeeding on breastfeeding-related conditions.METHODS In this study,207 mothers with postpartum breast pain and difficulty lactating were selected and divided into intervention and control groups using a random number table.Both groups of mothers were provided with basic nursing and related treatment measures after delivery.The intervention group additionally received care intervention with a health education form for breastfeeding.The scores of lactation volume,breast distension and pain,breastfeeding rate,breastfeeding self-efficacy,treatment effect,and complication rate of the two groups were compared.RESULTS After treatment,the breast pain score of the intervention group was significantly lower than that of the control group,while the lactation score,score of Breastfeeding Self-Efficacy Scale Short Form scale,parent-child communication score,maternal-infant interaction score,total score of maternal-infant communication,and breastfeeding rate of the intervention group were significantly higher than those of the control group.After intervention,the overall therapeutic effect of the intervention group was better than that of the control group,and the complication rate of the intervention group was lower than that of the control group.CONCLUSION Breastfeeding health education and nursing intervention combined with basic clinical treatment have good clinical effects in managing postpartum breast distension and pain and increasing lactation yield.

Changes in milk fat globule membrane proteins along lactation stage of Laoshan dairy goat

The milk fat globule membrane(MFGM)is a complex structure with numerous functions,and its composition is affected by many factors.There have been few systematic investigations on goat MFGM proteome profiling during lactation.Individual milk samples from 15 healthy dairy goats were obtained at six lactation time points for investigation of the MFGM proteome using both data-independent acquisition(DIA)and data-dependent acquisition(DDA)proteomics techniques combined with multivariate statistical analysis.Using the DIA method,890 variably abundant MFGM proteins were discovered throughout the lactation cycle.From 1 to 240 d,butyrophilin subfamily 1 member A1,lipoprotein lipase,perilipin-2,and adipose triglyceride lipase were upregulated,while APOE,complement C3,clusterin,and IgG were downregulated.Furthermore,from 1 to 90 d,annexin A1,annexin A2,and antithrombin-ll were downregulated,then upregulated by d 240.Albumin had a high degree of connectedness,indicating that it was a key protein,according to protein-protein interaction research.Overall,our findings gave new insights into the biological features of MFGM protein in goat milk throughout lactation,which may aid in the creation of specialized MFGM products and infant formula.

Psychological experience of breastfeeding among primiparous women with lactating mastitis:A qualitative research

Objective:The objective of this study is to comprehensively understand the psychological experience of primiparous women during breastfeeding while dealing with lactating mastitis and to establish a reliable foundation for tailored support measures.Methods:Twenty primiparous mothers from a tertiary hospital in Beijing between January and March 2023 were chosen using purposive sampling for semi-structured interviews.After conducting 20 interviews,data saturation was achieved.The Colaizzi’s seven-step analytical approach was employed to analyze,summarize,and refine the identified themes.Results:Among primiparous women afflicted by lactating mastitis,the primary themes regarding breastfeeding attitudes included three key aspects:(1)uncertainty during the initial diagnosis phase,(2)intricate emotional journey during treatment,and(3)positive psychological outlook during the recovery stage.Conclusion:Primiparous women undergoing lactating mastitis experience substantial physical and psychological strain.It is crucial for medical personnel,family caregivers,and society at large to be attuned to the emotions of these patients.Tailored support measures should be offered to enhance patients’physical and mental well-being and facilitate disease recovery.

Study on the Application Effect of Flexible Nursing Care in Patients with Postpartum Urinary Retention and its Effect on Lactation

Objective: To study the application effect of flexible nursing in patients with postpartum urinary retention and its effect on lactation. Methods: A total of 200 cases of postpartum urinary retention patients admitted between January 2021 and January 2022 were selected and randomly grouped into two groups, a control group (conventional nursing) and an observation group (flexible nursing), of 100 cases each. The time of onset of lactation, the lactation volume score, urinary indicators, the amount of post-partum hemorrhage, and the quality of life score of the two groups were compared. Results: The observation group’s lactation initiation time (21.41 ± 1.52) h and lactation volume score (2.11 ± 0.52) were better than that of the control group (P < 0.05). The observation group’s first urination time (2.11 ± 0.51) min was lower than the control group, while the urinary retention completely relieved time (33.12 ± 8.61) h, and first urinary volume (262.17 ± 52.41) mL was higher than that of the control group (P < 0.05). The amount of postpartum hemorrhage in the observation group (151.21 ± 22.12) mL was less than that in the control group (P < 0.05). The scores of somatic functioning (86.25 ± 2.20), psychological functioning (91.56 ± 1.45), social functioning (89.25 ± 2.45), and material life (89.75 ± 1.45) of the observation group were higher than those of the control group after nursing (P < 0.05). Conclusion: Flexible nursing care in patients with postpartum urinary retention exhibited significant nursing effects and lactation function was effectively improved.

Lactate Decreases Bortezomib Sensitivity and Predicts Poor Clinical Outcomes of Multiple Myeloma

Objective:Metabolic disorders are regarded as hallmarks of multiple myeloma(MM)and are responsible for rapid cancer cell proliferation and tumor growth.However,the exact biological roles of metabolites in MM cells have not been fully explored.This study aimed to explore the feasibility and clinical significance of lactate for MM and investigate the molecular mechanism of lactic acid(Lac)in the proliferation of myeloma cells and cell sensitivity to bortezomib(BTZ).Methods:Metabolomic analysis of the serum was carried out to obtain metabolites expression and clinical characteristics in MM patients.The CCK8 assay and flow cytometry were used to detect cell proliferation,apoptosis,and cell cycle changes.Western blotting was used to detect the potential mechanism and apoptosis-and cycle-related protein changes.Results:Lactate was highly expressed in both the peripheral blood and bone marrow of MM patients.It was significantly correlated with Durie-Salmon Staging(DS Staging)and the International Staging System(ISS Staging)and the serum and urinary involved/uninvolved free light chain ratios.Patients with relatively high lactate levels had a poor treatment response.Moreover,in vitro experiments showed that Lac could promote the proliferation of tumor cells and decrease the proportion of G0/G1-phase cells,which was accompanied by an increased proportion of S-phase cells.In addition,Lac could decrease tumor sensitivity to BTZ by disrupting the expression of nuclear factor kappa B subunit 2(NFκB2)and Re1B.Conclusion:Metabolic changes are important in MM cell proliferation and treatment response;lactate could be used as a biomarker in MM and as a therapeutic target to overcome cell resistance to BTZ.

Correlation of umbilical cord blood pH,base deficit,and lactate levels with outcomes of hypoxic newborns:A prospective study

Objective:To determine the association of the three umbilical cord blood parameters:umbilical cord pH,base deficit,and lactate levels,with neonatal outcomes.Methods:This prospective observational study was conducted from April 2021 to September 2022 with 100 term and late preterm(>35 weeks)neonates whose umbilical cord blood pH was<7.10,Apgar score was<7 at 1 min,and required positive pressure ventilation.Umbilical cord blood was assessed for pH,base deficit,and blood lactate levels.The neonatal outcomes of neonatal intensive care unit admission,Apgar score at 1 min,and Apgar score at 5 min were assessed.Results:The mean of umbilical cord blood pH was 7.04±0.07,mean base deficit was(−9.3±3.9)mmol/L,and mean lactate levels were(6.51±2.29)mmol/L.Neonatal intensive care unit(NICU)admission was needed in 78(78%)neonates.The mean NICU stay length was(2.4±2.2)days ranging from 0 to 12 days with a median of 2 days.Univariate analysis showed no significant difference in cord blood pH(P=0.736)and base deficit(P=0.393)between neonates without NICU admission and neonates who required NICU admission,but lactate level was significantly higher in neonates who required NICU admission(P<0.001).There was no significant difference in cord blood pH(P=0.400)and base deficit(P>0.999)between neonates with Apgar scores 4-7 at 1 min and neonates with Apgar scores<4,but lactate level was significantly higher in neonates with Apgar scores<4 at 1 min(P<0.001).Conclusions:Umbilical cord blood pH,base deficit,and lactate levels are useful novel markers showing a significant correlation with neonatal intensive care unit admission and adverse neonatal morbidities among hypoxic newborns.Overall,lactate was a better predictor of adverse neonatal outcomes as compared to umbilical cord blood pH and base deficit.

Role of cerebrospinal fluid lactate in diagnosing meningitis in critically ill patients

BACKGROUND Meningitis is a life-threatening clinical condition associated with high mortality and morbidity.Early diagnosis and specific treatment may improve outcomes.Lack of specific clinical signs or tests make the diagnosis challenging.AIM To assess the efficacy of cerebrospinal fluid(CSF)lactate in diagnosing meningitis in critically ill patients.METHODS A prospective,observational cohort study was carried out in a neuro-medical intensive care unit(ICU)over a 22 mo period.Adult patients,with suspected meningitis admitted in ICU,were serially recruited.Patients who refused consent,those with peripheral sensorineural deficit,or with any contraindication to lumber puncture were excluded.CSF cytology,bio-chemistry,lactates,culture and polymerase chain reaction based meningo-encephalitis panel were evaluated.Patients were divided in two groups based on clinical diagnosis of meningitis.The efficacy of CSF lactate in diagnosing meningitis was evaluated and compared with other tests.RESULTS Seventy-one patients were included and 23 were diagnosed with meningitis.The mean values of CSF total leucocyte count(TLC),proteins and lactates were significantly higher in meningitis group.There was a significant correlation of CSF lactate levels with CSF cultures and meningo-encephalitis panel.CSF lactate(>2.72 mmol/L)showed good accuracy in diagnosing meningitis with an area under the curve of 0.81(95% confidence interval:0.69-0.93),sensitivity of 82.6%,and specificity 72.9%.These values were comparable to those of CSF TLC and protein.Twelve patients with bacterial meningitis had significantly higher CSF lactate(8.9±4.7 mmol/L)than those with non-bacterial meningitis(4.2±3.8 mmol/L),P=0.006.CONCLUSION CSF lactate may be used to aid in our diagnosis of meningitis in ICU patients.CSF lactate(>2.72 mmol/L)showed good accuracy,sensitivity,and specificity in diagnosing meningitis and may also help to differentiate between bacterial and non-bacterial meningitis.

汽车电池用La-Mg-Ni基储氢合金的元素替代及电化学性能

采用感应熔炼方法制备了La_(0.7)R_(0.1)Mg_(0.2)Ni_(3.35)Al_(0.15)(R=La/Nd/Sm)储氢合金,研究了稀土元素Nd/Sm替代La对储氢合金相结构和电化学性能的影响。结果表明,采用Nd或Sm替代La时,储氢合金物相组成未发生改变,仍由LaNi_(5)、(LaMg)_(2)Ni_(7)和(LaMg)_(5)Ni_(19)相组成,但储氢合金中LaNi_(5)相和(LaMg)_(5)Ni_(19)相丰度会增加、(LaMg)_(2)Ni_(7)相丰度减小。R为La、Nd和Sm时储氢合金的最大放电比容量均在第2次充放电循环时获得,分别为377 mAh/g、382 mAh/g和376 mAh/g;采用Nd或Sm替代La,储氢合金高倍率放电性能、24 h荷电保持率和充放电循环100次时的容量保持率都不同程度地增加,且R为Nd时储氢合金的相应值最大。采用Nd或Sm替代La会使得储氢合金的交换电流密度、氢扩散系数增加,储氢合金电极的高倍率放电性能与交换电流密度和氢扩散系数变化趋势一致,表明储氢合金电极的高倍率放电性能由交换电流密度和氢扩散系数共同决定。

虚拟筛选竞争性抑制NDRG3与L-Lactate结合的小分子研究

竞争性抑制NDRG3(N-myc Downstream Regulated Gene 3)蛋白与L-Lactate结合可有效阻遏NDRG3介导的低氧反应.文中通过同源模建技术构建NDRG3蛋白的三维结构,并将L-Lactate对接到NDRG3蛋白的潜在活性位点中,发现L-Lactate主要通过与Asn133、Ala162、His163、His164、Ser235、Pro236及Ala237等氨基酸相互作用结合于NDRG3.对近3 000个化合物进行虚拟筛选,选择4种竞争性抑制最强的化合物作为参考分子分析相互作用关系.结果发现:部分化合物和不同氨基酸能够通过不同的作用力与NDRG3蛋白结合,占据NDRG3蛋白的活性位点,从而竞争性抑制L-Lactate与NDRG3蛋白结合.例如,它们能够与Lys139、Asp143、His163、Arg203产生静电作用;它们与His163形成π-π堆积作用;它们与Phe165、Ala237等产生疏水作用;它们与Asn133、Asp135、Gly140、Arg203、Ser235、Ala237等形成氢键作用.以上数据表明:这些化合物可能成为阻遏NDRG3介导的低氧反应及靶向治疗低氧诱导疾病的候选药物.

重熔对Al-Ti-La中间合金中Ti_(2)Al_(20)La相的影响

通过扫描电镜、X射线衍射和电子探针等分析研究了重熔过程中不同保温时间和温度对Al-Ti-La中间合金中Ti_(2)Al_(20)La相的含量、形态尺寸和稳定性的影响。结果表明:在750℃下,随着保温时间的延长,Ti_(2)Al_(20)La相的溶解度逐渐增大,含量由未处理的20.776%下降至13.72%,形态由块状演变为圆整和细小的片状,长宽比由2.33下降至1.52;在1000℃下,保温15 min后溶解度较大,含量降低至4.5%,形态演变为尖锐的长条状,长宽比上升至2.55;溶解产生的La原子与Al在晶界处形成La-Al金属间化合物(IMC),Ti原子在基体中的分布密度随保温时间的延长和保温温度的升高而增高,以游离态均匀分布在基体中。

La-Ce稀土对Q345D钢夹杂物和冲击性能的影响

通过现场试验,分析了La-Ce稀土处理对Q345D结构钢夹杂物、连铸可浇性和钢种性能的影响。结果表明,RE在Q345D结构钢中的合金收得率为21.5%;与未添加RE的炉次相比,脱硫率提高了37.5%,单位夹杂物密度从80.16个/mm^(2),降低至60.78个/mm^(2);La-Ce稀土处理前钢液中夹杂物主要是MgO-Al_(2)O_(3)-CaO复合夹杂,La-Ce稀土处理对小尺寸(D≤5μm)夹杂物的改性作用较为明显,小尺寸夹杂物改性为(La-Ce-S)和(La-Ce-Al-S-O)稀土类夹杂物;La-Ce稀土处理可以明显降低钢中MnS类夹杂物的纵横比,使MnS类夹杂物在轧制后的形貌更接近椭圆形,而没有长线形,这是Q345D结构钢横向冲击功提高20%的主要原因。

Determination of Ciprofloxacin Lactate by Sodium Tetraphenylboron Method

This paper describes an effective method for determining ciprofloxacin lactate. An excess of sodium tetraphenylboron was added to precipitate ciprofloxacin lactate in HAc-NaAc buffer solution (pH=4.0). After filtering off the precipitate, the excessive sodium tetraphenylboron in the filtrate was titrated with cetyltrimethylammonium bromide standard solution, with bromophenol blue as indicator. The method is simple and rapid, it has been applied to the determination of ciprofloxacin lactate raw material with satisfactory results. The recovery was between 99.66% and 100.2%, the relative error was less than ±0.40%. Experiments showed that the method gave the same results as the approach using nonaqueous titration (ChP).