Flocculation Mechanism of Synthetic Goethite Suspension Using Hydroxamated Polymer and Sodium Polyacrylate

The flocculation effects of homemade hydroxamated flocculant(HPAA)and commercially available sodium polyacrylate(PAAS)on synthetic goethite suspensions with different solid contents were studied.The adsorption mechanism of HPAA or PAAS on the surfaces of goethite was investigated.The settling rate of 50 g/L goethite suspension with HPAA(1.74 m/h)was faster than that with PAAS(0.54 m/h),which indicated that HPAA exhibits better flocculation performance than PAAS does.It could be found that the stretching vibration of carbonyl band in hydroxamic acid groups of HPAA was downshifted from 1 654 cm^(-1) to 1 645 cm^(-1) and a new adsorption band appeared at 1 455 cm-1,which demonstrated that a five-membered ring chelate may be formed among iron atoms of goethite surfaces,the hydroxyl groups and the carbonyl groups in hydroxamic acid groups of HPAA.In the case of PAAS,the separation of the asymmetric and symmetric stretches of the carboxylate groups in adsorbed PAAS was 163 cm-1,which was greater than that of unadsorbed PAAS with 157 cm^(-1).There was no indication of a contribution from the monodentate adsorption between iron atoms of goethite surfaces and carboxylate groups of PAAS,but there may exist a bi-dentate bridging structure.Compared with synthetic goethite,XPS curve fittings of Fe 2p spectra showed that the binding energies of the main Fe 2p3/2 and Fe 2p1/2 resolved peaks on HPAA-treated goethite surfaces were correspondingly decreased by 0.9 and 0.7 e V,while those on PAAS-treated goethite surfaces were correspondingly decreased by 0.7 and 0.3 e V.The characteristic N 1s peak of HPAA and C 1s peak of PAAS were correspondingly detected on HPAA-treated and PAAS-treated goethites,and a binding energy change of N 1s spectrum of adsorbed HPAA was observed.The relative atomic ratios of C/Fe,N/Fe and O/Fe on HPAA-treated and PAAS-treated goethite surfaces were increased.All the results suggested that HPAA or PAAS was adsorbed on the goethite surfaces by the chemisorption,and a stronger adsorption of HPAA on the goethite surfaces happened than that of PAAS.

Preparation of cinnamic hydroxamic acid collector and study on flotation characteristics and mechanism of scheelite

In this paper,using methyl cinnamate as raw material,the new cinnamic hydroxamic acid collector(CIHA)was synthesized by the hydroxylamine method.The collector performance of hydroxamic acid was investigated for scheelite and gangue calcite,and the flotation separation test of scheelite and calcite was carried out with CIHA as the collector.The interaction mechanism between hydroxamic acid and scheelite minerals has also been investigated through zeta potential,Fourier transform infrared spectroscopy(FTIR)experiments,X-ray photoelectron spectroscopy(XPS)experiments,and density functional theory(DFT)calculation.The single mineral flotation test and artificially mixed ore showed that CIHA had an excellent collection effect and selectivity.Zeta potential,FTIR,and XPS showed that CIHA was adsorbed on the scheelite surface by strong chemical adsorption.The active group of CIHA was analyzed through quantum chemical calculation.It was speculated that C=O and N-O bonds could synthesize a five-membered chelated hydroxamic acid group with Ca element chelate on scheelite surface,changing hydrophobicity and making it more likely to emerge from the pulp.

Suberoylanilide hydroxamic acid upregulates reticulophagy receptor expression and promotes cell death in hepatocellular carcinoma cells

BACKGROUND Hepatocellular carcinoma(HCC)is a common clinical condition with a poor prognosis and few effective treatment options.Potent anticancer agents for treating HCC must be identified.Epigenetics plays an essential role in HCC tumorigenesis.Suberoylanilide hydroxamic acid(SAHA),the most common histone deacetylase inhibitor agent,triggers many forms of cell death in HCC.However,the underlying mechanism of action remains unclear.Family with sequence similarity 134 member B(FAM134B)-induced reticulophagy,a selective autophagic pathway,participates in the decision of cell fate and exhibits anticancer activity.This study focused on the relationship between FAM134B-induced reticulophagy and SAHA-mediated cell death.AIM To elucidate potential roles and underlying molecular mechanisms of reticulophagy in SAHA-induced HCC cell death.METHODS The viability,apoptosis,cell cycle,migration,and invasion of SAHA-treated Huh7 and MHCC97L cells were measured.Proteins related to the reticulophagy pathway,mitochondria-endoplasmic reticulum(ER)contact sites,intrinsic mitochondrial apoptosis,and histone acetylation were quantified using western blotting.ER and lysosome colocalization,and mitochondrial Ca^(2+)levels were characterized via confocal microscopy.The level of cell death was evaluated through Hoechst 33342 staining and propidium iodide colocalization.Chromatin immunoprecipitation was used to verify histone H4 lysine-16 acetylation in the FAM134B promoter region.RESULTS After SAHA treatment,the proliferation of Huh7 and MHCC97L cells was significantly inhibited,and the migration and invasion abilities were greatly blocked in vitro.This promoted apoptosis and caused G1 phase cells to increase in a concentration-dependent manner.Following treatment with SAHA,ER-phagy was activated,thereby triggering autophagy-mediated cell death of HCC cells in vitro.Western blotting and chromatin immunoprecipitation assays confirmed that SAHA regulated FAM134B expression by enhancing the histone H4 lysine-16 acetylation in the FAM134B promoter region.Further,SAHA disturbed the Ca^(2+)homeostasis and upregulated the level of autocrine motility factor receptor and proteins related to mitochondria-endoplasmic reticulum contact sites in HCC cells.Additionally,SAHA decreased the mitochondrial membrane potential levels,thereby accelerating the activation of the reticulophagy-mediated mitochondrial apoptosis pathway and promoting HCC cell death in vitro.CONCLUSION SAHA stimulates FAM134B-mediated ER-phagy to synergistically enhance the mitochondrial apoptotic pathway,thereby enhancing HCC cell death.

MMP-2和Hydroxamate类抑制剂绝对自由能的计算

采用基于线性响应近似的自由能计算方法计算了一类hydroxamate抑制剂和MMP 2的绝对结合自由能 .计算中 ,催化锌离子和MMP 2以及配体之间采用了非键模型 .分子动力学模拟结果显示 ,采用非键模型时 ,催化Zn离子采用五配位的形式 ,但配位键的形式和初始结构比较有很大的差别 .通过拟合 ,分别得到了单参数、双参数以及三参数的自由能预测模型 ,其中 ,含有常数校正项的三参数模型具有最佳的预测能力 ,预测自由能和实际自由能之间平均绝对误差仅为 2 .38kJ/mol.

Hydroxamate类抑制剂与MMP—3的结合自由能的计算

用自由能微扰方法(FEP)计算了两种hydroxamate类的抑制剂和MMP-3的相对结合自由能.在计算中,对于催化区的锌离子与其共价结合的配体(包括抑制剂和组氨酸)采用了键合的模型,抑制剂和周围配体的部分电荷的计算采用两步静电势收敛方法.自由能计算采用了慢增长(Slow growth)和固定窗口增长(Fixed width window growth)两种方法,并且在每次计算中都采用了双向采样(Double-wide sampling)的策略.两种方法计算得到的相对结合自由能都能和实验值很好的符合.同时从动力学模拟的得到的分子轨迹得到了抑制剂和受体之间相互作用模式,抑制剂的P1部分可以和受体的S1′口袋形成很强的范德华和疏水相互作用,P1上的苯环可以和Tyr223上的苯环形成较好的π键堆积相互作用.

Hydroxamate类抑制剂与MMP—2的分子对接研究

通过分子动力学模拟研究了MMP-2和hydroxamate抑制剂之间的作用模式.在分子动力学模拟中,对于催化区的锌离子和其共价结合的配体(包括抑制剂和组氨酸)采用了键合的模型.从模拟的结果可以看到,R1取代基和MMP-2的S1疏水口袋中的部分残基能形成很好的几何匹配,从而可以产生很强的范德华和疏水相互作用.模拟结果也表明,两个抑制剂和MMP-2之间分别能形成5个和8个氢键,抑制剂B比A活性更高的原因就是能够形成更加有利的氢键作用模式.在整个模拟过程中,催化锌都能保持好的五配位形式,配位键的长度也处于稳定的状态.预测得到的MMP-2和其抑制剂的相互作用模式对于全新抑制剂的设计提供了非常重要的结构信息.

新显色剂PMNHA的合成、分析鉴定及其在分光光度测定钒中的应用

用１－甲基－２－萘甲酰基替换Ｎ－苯甲酰苯基羟胺（ＢＰＨＡ）的苯甲酰基，合成了一种新显色剂Ｎ－苯基－１－甲氧基－２－萘甲酰氧肟酸（Ｎ－ｐｈｅｎｙｌ－１－ｍｅｔｈｏｘｙ－２－ｎａｐｈｔｈｏｙｌｈｙｄｒｏｘａｍｉｃａｃｉｄ，缩写为ＰＭＮＨＡ）。根据元素分析、差热分析、质谱分析、核磁共振、红外光谱分析，确定ＰＭＮＨＡ的组成和结构为：ＯＣＨ３ＣＯＮＯＨＣ６Ｈ５。该试剂的三氯甲烷溶液能很快从２．２５—４．５０ｍｏｌ／ＬＨＣｌ中萃取钒（Ⅴ）的紫色配合物，其配合物最大吸收在５４０ｎｍ，很多外来离子，特别是大量的钛不干扰钒的测定，钒含量在０—２８μｇ·ｇ－１范围遵守比耳定律。

Dioxygen Affinities and Catalytic Epoxidation Performanceof Transition-Metal Hydroxamates

The dioxygen affinities and catalytic epoxidation performance of transition-metal hydroxamates were investigated for the first time. The effects of substituents on these properties were also discussed in the paper.

A Simple Method for the Isolation and Purification of 2,4-Dihydroxy-7-Methoxy-2H-1,4-Benzoxazin-3(4H)-One (DIMBOA) from Maize (Zea mays L.) Seedlings

2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3（4H）-one （DIMBOA）, the dominant benzoxazinoid hydroxamic acid in maize （Zea Mays L.）, serves as important factors of resistance against insects and microbial diseases, allelochemicals used in competition with other plants. In this paper, a novel and simple method for the isolation and purification of DIMBOA from maize seedlings was developed. Frozen shoots from 7-d-old maize seedlings （1 000×g） were firstly defrosted and then were directly homogenized and extracted with ethyl acetate. The macerate was allowed to stand at room temperature （25±2）°C for 1 h to allow enzymatic release of DIMBOA from DIMBOA-glucoside. Then the ethyl acetate phase was filtered, dried and evaporated to dryness. The resulting light-tan, semicrystalline residue was stored at -20°C for 24 h. Upon recrystallization from acetone-hexane, a relative higher yield （0.58 g） of pure DIMBOA crystals was obtained compared with the yield afforded by Woodward methodology （0.26 g）.

Histone deacetylase inhibitor suberoylanilide hydroxamic acid alleviates liver fibrosis by suppressing the transforming growth factor-β1 signal pathway

Background: Histone deacetylases(HDACs) inhibitors are new anti-fibrotic drugs that inhibit the activity of hepatic stellate cells. The present study focused on the anti-fibrotic function of HDAC inhibitor suberoylanilide hydroxamic acid(SAHA) by suppressing transforming growth factor-β1(TGF-β1) signaling. Methods: Male Sprague-Dawley rats were used to induce liver fibrosis with carbon tetrachloride(CCl 4) and LX2 cell(human hepatic stellate cell line) was stimulated by TGF-β1. Both animals and cells were treated with SAHA. The Smad7 and connective tissue growth factor(CTGF) mRNA levels were detected by real-time polymerase chain reaction(PCR). Western blotting was used to examine the protein levels of CTGF, Histone H3(H3), Smad7, Smad2/3, Acetyl-Histone H3(AH3), HDAC2, α-smooth muscle actin( α-SMA), HDAC6, p-Smad2/3 and HDAC8. In addition, the TGF-β1 and liver enzyme levels from rat serum were detected. Histopathological changes were examined by hematoxylin and eosin(HE), Sirius red and Masson trichrome staining. The α-SMA expression was detected by immumohistochemical staining. Results: Compared with control group, the TGF-β1 and liver enzyme levels from rat serum, together with the mRNA levels of CTGF and protein levels of CTGF, HDAC2, α-SMA, HDAC6, p-Smad2/3 and HDAC8 were elevated in fibrotic rats( P < 0.01). But the Smad7 mRNA and AH3 protein levels were notably suppressed in the fibrotic rats( P < 0.01). Pathological examination showed the typical changes of liver fibrosis in the fibrotic rats. After the treatment with SAHA, the levels of liver enzymes, TGF-β1, CTGF, HDAC2, α-SMA, HDAC6, p-Smad2/3 and HDAC8 were reduced( P < 0.01) and Smad7 and AH3 protein contents were elevated in liver fibrotic rats( P < 0.01). Moreover, immumohistochemistry showed that SAHA significantly suppressed the α-SMA protein content in fibrotic liver( P < 0.01). Conclusion: The HDAC inhibitor SAHA alleviated liver fibrosis by suppressing the TGF-β1 signaling.

Dioxygen Affinities and Catalytic Oxidation Performance of Cobalt (Ⅱ)Complexes with N—Aryl Hydroxamic Acid

The oxygenation of cobalt (II) hydroxamates (CoL2) and its catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) were examined. The effects of X and Y bonded to hydroxamate group on dioxygen affinities and catalytic oxidation performance were also investigated.

Studies of benzyl hydroxamic acid/calcium lignosulphonate addition order in the flotation separation of smithsonite from calcite

Flotation separation of smithsonite from calcite is difficult due to their similar surface properties.In the present study,a reagent scheme of depressant calcium lignosulphonate(CLS) and collector benzyl hydroxamic acid(BHA) was introduced in the flotation of smithsonite from calcite.Microflotation tests revealed that the efficient flotation of smithsonite from calcite could only be obtained with the addition order of BHA before CLS,which was opposite to the widely-used order that adding depressant prior to the collector.The zeta potential measurements indicated that BHA selectively adsorbed onto smithsonite surface,then not allowed the CLS adsorption onto the smithsonite surface rather than calcite surface because of the steric hindrance,thereby the smithsonite surface remained hydrophobic while calcite surface became more hydrophilic after the addition of CLS.As a result,the calcite flotation was completely depressed while the smithsonite flotation recovery was still in high value,leading to the optimal flotation separation performance.

Effects of SAHA on proliferation and apoptosis of hepatocellular carcinoma cells and hepatitis B virus replication

AIM: To investigate the effects of suberoylanilide hydroxamic acid(SAHA) on proliferation and apoptosis of a human hepatocellular carcinoma cell line(HepG2.2.15) and hepatitis B virus(HBV) replication.METHODS: HepG2.2.15 cells were treated with different concentrations of SAHA.Cell morphology was examined by confocal laser scanning microscopy,and cell proliferation was determined using a MTT colorimetric assay.Flow cytometry was used to detect apoptosis and determine cell cycle phase,while hepatitis B surface antigen and hepatitis B e antigen content were measured using chemiluminescence.Reverse transcription polymerase chain reaction was performed to measure HBV DNA in cell lysate.RESULTS: Cell proliferation rates were significantly reduced by the addition of SAHA.The inhibitory effect of SAHA on cell proliferation was both time-and dosedependent.After 24 h of treatment with SAHA,the early cell apoptotic rate increased from 3.25% to 21.02%(P = 0.041).The proportion of G0 /G1 phase cells increased from 50.3% to 65.3%(P = 0.039),while that of S phase cells decreased from 34.9% to 20.6%(P = 0.049).After 48 h of treatment,hepatitis B surface antigen and hepatitis B e antigen content increased from 12.33 ± 0.62 to 25.42 ± 2.67(P = 0.020) and 28.92 ± 1.24 to 50.48 ± 1.85(P = 0.026),respectively.Furthermore,HBV DNA content increased from 4.54 ± 0.46 to 8.34 ± 0.59(P = 0.029).CONCLUSION: SAHA inhibits HepG2.2.15 cell proliferation,promotes apoptosis,and stimulates HBV replication.In combination with anti-HBV drugs,SAHA may potentially be used cautiously for treatment of hepatocellular carcinoma.

Extraction Separation of Germanium with Hydroxamic Acid HGS98

The extraction separation of germanium from indium raffinate in hydrometallurgical zinc process was discussed. The conditions and mechanism of the extraction with hydroxamic acid HGS98 have been investigated in detail. The results show that u sing 2% (mass fraction) hydroxamic acid HGS98 and 5% D 2EHPA as synergist, germanium is extracted (1 stage) over 99% in 5 min at phase ratio ( V o∶ V a) of 1∶5 from indium raffinate with original acidity. Then, using 2 mol·L -1 NH 4F as strip liquor, the stripping recovery is over 98% in 15 min at phase ratio of 1∶1. This process has the following advantages:easy to operate, high recovery and selectivity, and lower investment cost. It provides a new way to recover rare metal-germanium from metallurgical spent residues.

Synthesis and spectroscopic characterization of fluorescent solid rare-earth complexes with hydroxamic acids

The complexes RE_2(DHYA)_3 centre dot nH_2O in the title bar were synthesizedthrough some reactions of trivalent rare-earth ions. In the process of synthesis, dihydroxamicacids were taken as ligands while the alcohol was taken as a solvent. The ligands includedadipylhydroxamic acid (ADHA), p-phthalichydroxamic acid (PPHA), oxalohydroxamic acid (OXHA),butadihydroxamic acid (BDHA), o-phthalichydroxamic acid (OPHA), benzoylhydroxamic acid (BHA), etc.Measured at 25 deg C, the molar conductances in various modes are 13.00-21.05 S centre dot cm^2centre dot mol^(-1), which shows that rare-earth complexes are nonelectrolytes and the hydroxaminogroups of the complexes have taken part in bonding. Infrared spectra, ultraviolet spectra, nuclearmagnetic resonance (~1HNMR) spectra, and fluorescence spectra were used to investigate thecomplexes. Experiments have proved that the complexes of En^(3+)and Tb^(3+) with aromatic hydroxamicacids have good fluorescent characteristics.

Solvent extraction separate of zinc and cadmium from magnesium and calcium in sulfuric acid medium by mixing extractants

Synergistic extraction has been proven to enhance extractability and selectivity for the separation of cadmium and zinc from magnesium and calcium in the sulfuric acid medium with Mextral V10 and Mextral 622H(aromatic hydroxamic)mixtures diluted in DT100.Mixtures of Mextral V10 and 622H are highly selective for Zn and Cd over Mg and Ca compared with the single Mextral V10,resulting in larger synergistic shifts for zinc and cadmium with theΔpH_(50(Zn–Ca))values increasing substantially from0.83 to 1.73 pH units andΔpH_(50(Cd–Ca))values increasing from 0.63 to 2.13 p H units.The aqueous to organic ratio(A/O ratio),the saponification ratio of Mextral V10 and extracting agent concentration were studied on the effect of metal ions extraction,which helped to increase the organic capacity of metal extraction.The Mc Cabe-Thiele plot for Cd and Zn extraction with 5%(volume fraction)Mextral V10 and 5%Mextral 622H extractants mixture indicate the necessity of only one theoretical stages at an A/O ratio of 1.5:1.One stage extraction simulation test conducted at pH 6.50 shows that Cd and Zn reach the extraction of 99.6%and 97.9%,respectively,and only low levels of magnesium and calcium are extracted in the organic phase.The extracted Zn^(2+)or Cd^(2+)-organic species are Zn(A_1)(A_2)or Cd(A_1)(A_2)with the mixture system by slope analysis.

Preparation and determination of hydroximic polyacrylamide

A new kind of polyacrylamide derivate, hydroximic polyacrylamide (HPAM), was prepared from polyacrylamide (PAM) with hydroxylamine hydrochloride in KOH/alcohol solution. Based on colorimetric method in the measurement of C 7 9 alkyl hydroximic acid, the substitution degree of HPAM was determined by selecting octyl hydroximic acid as a primary standard substance. The effects of temperature, the amount of hydroxylamine and potassium hydroxide, and the reaction time on the reaction are discussed. HPAM with 5.78% substitution of degree was acquired by optimizing the reaction conditions. IR spectra revealed that tautomerism appears in the HPAM, and that HPAM exists in both the forms of hydroxamic type and hydroximic type, and the latter type can easily lead to the forming of intramolecular hydrogen bond.

Dioxygen affinities and catalytic oxidation performance of cobalt(Ⅱ) hydroxamates with benzo-15-crown-5 pendants

The oxygenation constants （Ko2） of cobalt（Ⅱ） hydroxamates （CoL^1 2-CoL^3 2） with benzo-15-crown-5 （B15C5） pendants were measured over the range of -5 to ＋20 ℃, and the values of thermodynamic parameters （ΔH^0 and ΔS^0） were calculated based on these （Ko2） values, Meanwhile, these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110Δ under normal atmospheric pressure. The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O2-binding capabilities and oxidation for p-xylene were investigated with the comparison of crown-free analogues CoL^4 2.

Synthesis,Structure,and Luminescent Property of a 3-D Zinc Complex {[Zn_8^(II)(4-APha)_8(CH_3COO)_8](CH_3CH_2OH)_2}_n

The title complex [ZN8II（4-APha）8（CH3COO）8（CH3CH2OH）2]n （1, 4-APha = 4-ami- nophenylhydroxamic acid） has been prepared under solvothermal conditions. It has been characterized by X-ray single-crystal diffraction, IR and elemental analysis. The crystal belongs to the monoclinic system, space group C2/c with a = 39.074（4）, b = 9.9645（8）, c=38.846（3） A, β = 136.438°, V= 10423.1（14） A3, C84H118N16O39Zn8, Mr = 2498.90, Z = 4, Dc = 1.592 g/cm3,μ= 1.900 mm-1, F（000） = 5144, the final R = 0.1036 and wR = 0.2953. This complex possesses a 3-D structure which is constructed from 1-D chain motifs linked by the 4-APha＂ ligands. The luminescent property of the title complex has been investigated.

Synthesis,Crystal Structure and Properties of Complex VO(C_(12)H_(12)N_2O_2)(C_(13)H_(10)NO_2)

Complex VO(C\-\{12\}H\-\{12\}N\-2O\-2)(C\-\{13\}H\-\{10\}NO\-2)(C\-\{12\}H\-\{12\}N\-2O\+\{\{\}\+\{2-\}\}\-2=acetylacetone benzoylhydrozanate,C\-\{13\}H\-\{10\}NO\+_\-2=\%N\%\|phenylbenzohydroxamate) was synthesized and characterized by means of elemental analysis,IR and UV spectroscopies,cyclic voltammetry and single crystal X\|ray diffraction. The complex crystallized in the monoclinic system with space group \%P\%2\-1/\%n\% and the crystal cell parameters \%a\%=1\^3003(1) nm,\%b\%=0\^88836(6) nm,\%c\%=2\^0196(2) nm,\%β\%=95\^065(8)°,\%V\%=2\^3238(3) nm\+3,\%M\%\-r=495\^40 and \%Z\%=4. The two oxygen and one nitrogen atoms of the tridentate hydrazone ligand coordinate to the vanadium atom,forming an equatorial plane. And the coordinated vanadium atom exhibits a distorted octahedral geometry. The atom in the transposition to the oxo O atom is the carbonyl oxygen atom of the hydroxamate ligand in the complex. The half\|wave redox potential of the title complex in the three different solvents positively shifts in the order of CH\-2Cl\-2<CH\-3CN<DMF.