Conformational spaces of the gastrointestinal antisecretory chiral drug omeprazole: stereochemistry and tautomerism

A study of the conformational spaces of the chiral proton pump inhibitor (PPI) drug omeprazole by semiempirical, ab-initio, and DFT methods is described. In addition to the chiral center at the sulfinyl sulfur atom, the chiral axis at the pyridine ring (due to the hindered rotation of the 4-methoxy substituents) was considered. The results were analyzed in terms of the 5-methoxy and 6-methoxy tautomers and the two pairs of enantiomers (R,P)/(S,M) and (R,M)/(S,P). Five torsion angles were systematically explored: the backbone rotations defined by D1 (N3-C2-S10-O11), D2 (C2-S10-C12-C13), and D3 (S10-C12-C13-N14) and two methoxy rotations defined by D4 (C6-C5-O8-C9) and D5 (C16-C17-O19-C20). Significant energy differences were revealed between the 5- and 6-methoxy tautomers, the extended and folded conformations, and the (S,M) and (S,P) diastereomers. The "extended M" conformation of the 6-methoxy tautomer of (S)-omeprazole was found to be the most stable conformer.     

Novel binuclear chiral zirconium catalysts used in enantioselective strecker reactions

A novel binuclear chiral zirconium catalyst was successfully used in enantioselective Strecker reactions. The catalyst was readily prepared from zirconium t-butoxide (Zr(OtBu)4), (R)-6,6'-dibromo-1, 1'-bi-2-naphthol ((R)-6-Br-BINOL), and (R)-3,3'-dibromo-1, 1'-bi-2-naphthol ((R)-3-Br-BINOL) to form unique binuclear structure. It was revealed that a combination of (R)-6-Br-BINOL and (R)-3-Br-BINOL was essential in these asymmetric reactions and that much lower selectivities were obtained by using other combinations. Two-component (an imine and hydrogen cyanide (HCN)) and three-component (an aldehyde, an amine, and HCN) Strecker reactions proceeded smoothly in the presence of a catalytic amount of the chiral zirconium catalyst to afford the corresponding alpha-amino nitrile derivatives in high yields with high enantioselectivities.     

Antibodies against (1R,2R)-cyclohexanediamineplatinum(II)-DNA adduct recognize the conformational differences of isomeric analogues of cyclohexanediamine

Antibodies reactive to (1R,2R)-cyclohexanediamineplatinum(II)-DNA ((1R,2R)-cyclohexanediamine: 1R,2R-dach) adducts were elicited by immunization of rabbit with calf thymus DNA modified by Pt(1R,2R-dach)Cl2 at a ratio of bound platinum per nucleotide ((D/N)b) of 0.0335. In an enzyme-linked immunosorbent assay (ELISA), the binding of specific antibodies to Pt(1R,2R-dach)-DNA adduct (60 microliters of 1.235 x 10(-7) M Pt in each wells) on the assay plate was competitively inhibited by Pt(1R,2R-dach)-DNA adduct ((D/N)b = 0.0653) in the solution. Almost equal inhibition was observed with Pt(1S,2S-dach)-DNA ((D/N)b = 0.0412), an optical isomer of 1R,2R-dach. Pt(1R,2S-dach)-DNA ((D/N)b = 0.0371) and Pt(1R,3S-dach)-DNA ((D/N)b = 0.0281) in which the cyclohexane ring is stereochemically perpendicular to the platinum chelate plane, also inhibited antibody binding, but these adducts gave only incomplete inhibition at higher Pt-DNA adduct concentrations. Although Pt(1R,2R-dach)-d(GpG) and Pt(1R,2R-dach)(NH3)2 inhibited antibody binding, the affinity of the antibody for Pt(1R,2R-dach)(NH3)2 was lower than with Pt(1R,2R-dach)-DNA, and the inhibition behavior of Pt(1R,2R-dach)-d(GpG) was biphasic, i.e., at the lower concentration the inhibition curve was consistent with that of Pt(1R,2R-dach)-DNA, but at the higher concentration it shifted to that of Pt(1R,2R-dach)(NH3)2. The affinity of the antibody for cis-DDP was markedly lower than with Pt(1R,2R-dach)(NH3)2. These facts suggest that the antibodies may bind to the substituents (the platinum and its surroundings) of the various Pt complexes rather than the DNA structure altered by platinum binding.     

Absorption, fluorescence, and cd spectroscopic study of chiral recognition by a binaphthyl-derived chromogenic calixcrown host

The (R)- and (S)-enantiomers of a binaphthyl-appended calix[4]crown-6 ether with two 2,4-dinitrophenylazo chromophore units ((R)-1 and (S)-1) as chiral hosts were tested in their reactions with the enantiomers of alpha-methylbenzylamine ((R)-MBA, (S)-MBA)) and phenylglycinol ((R)-PGL, (S)-PGL) as chiral guests. The visible absorption spectra indicate a two-step process: the first is a nonenantioselective proton transfer from the host to the guest, which is followed by the enantioselective real complexation. In the visible range of the CD spectra a positive/negative band belongs to the absorption of pure (R)-1/(S)-1, and a negative/positive exciton couplet to the absorption of (R)-1-(S)-MBA/(S)-1-(R)-MBA complexes. The latter phenomenon suggests that the complexation of amines is accompanied by a chiral arrangement of the two chromophore units in the hosts. The UV fluorescence of (R)-1/(S)-1 arising from the binaphthyl moiety is quenched by K+ ions, but not by the amine guests, showing that the interaction between the binaphthyl group and the complexed amines is weak.     

The molecular and crystal structures of 4-N-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-l-asparagine trihydrate and 4-N-(β-d-glucopyranosyl)-l-asparagine monohydrate. The X-ray analysis of a carbohydrate–peptide linkage

X-ray analyses have shown that the glucopyranose rings of GlcNAc-Asn [4-N-(2-acetamido-2-deoxy-beta-d-glucopyranosyl)-l-asparagine] and Glc-Asn [4-N-(beta-d-glucopyranosyl)-l-asparagine] both have the C-1 chair conformation and also that the glucose-asparagine linkage of each molecule is present in the beta-anomeric configuration. The dimensions (the estimated standard deviations of the last digit are in parentheses) of the glycosidic bond in GlcNAc-Asn and Glc-Asn are, respectively, C((1))-N((1)) 0.1441(6)nm, 0.146(2)nm; angle O((5))-C((1))-N((1)) 106.8(3) degrees , 105.7(8) degrees ; angle C((2))-C((1))-N((1)) 111.1(4) degrees , 110.4(9) degrees ; angle C((1))-N((1))-C((9)) 121.4(4) degrees , 120.5(9) degrees . The glycosidic torsion angle C((9))-N((1))-C((1))-C((2)) is 141.0 degrees and 157.6 degrees in GlcNAc-Asn and Glc-Asn respectively. Hydrogen-bonding is extensive in these two crystal structures and does affect one torsion angle in particular. Two very different values of chi(1)(N-C(alpha)-C(beta)-C(gamma)) occur for the asparagine residue of the two different molecules; the values of chi(1), -69.0 degrees in GlcNAc-Asn and 61.9 degrees in Glc-Asn, correspond to two different staggered conformations about the C(alpha)-C(beta) bond as the NH(3) (+) group is adjusted to different hydrogen-bonding patterns. The two trans-peptide groups in GlcNAc-Asn show small distortions in planarity whereas that in Glc-Asn is more non-planar. The mean plane through the atoms of the amide group at C((2)) in GlcNAc-Asn is approximately perpendicular (69 degrees ) to the mean plane through the C((2)), C((3)), C((5)) and O((5)) atoms of the glucose ring and that at C((1)) is less perpendicular (65 degrees ). The mean plane through the atoms of the amide group in Glc-Asn makes an angle of only 55 degrees with the mean plane through these same four atoms of the glucose ring. The N((1))-H bond of the amide at C((1)) is trans to the C((1))-H bond in these two compounds; the N((2))-H bond of the amide at C((2)) is trans to the C((2))-H bond in GlcNAc-Asn. The values of the observed and final calculated structure amplitudes have been deposited as Supplementary Publication SUP 50035 (26 pages) at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.     

不同基因型水生植物对铵态氮和硝态氮吸收动力学特性研究

针对不同营养状况的富营养化水体修复而选择吸收养分效率较强的水生植物,采用改进常规耗竭法比较研究了6种不同基因型水生植物凤眼莲(Eichhornia crassipes Solms)、黄花水龙(Jussiaea stipulacea Ohwi)、再力花(Thalia dealbata Fraser)、美人蕉(Canna glauca L.)、水芹[Oenanthe javanica(Bl).DC]和豆瓣菜(Nasturtium officinaleR.Br.)对铵态氮和硝态氮吸收动力学特性。结果表明,不同基因型水生植物吸收铵态氮和硝态氮的动力学特性可用Michaelis-Menten方程来描述。在低浓度培养下,不同基因型水生植物对NH4+-N和NO3--N吸收的动力学参数Imax和Km差异较大,其吸收NH4+-N和NO3--N的Imax最大是水芹,其次是豆瓣菜;Km值最小的是水芹,其次是豆瓣菜;且水芹对NH4+-N和NO3--N不仅具有较强的亲和力,还具有较高的离子吸收速率。结果还表明,当介质中氮浓度较低时,水芹有优先吸收硝态氮的趋势,而豆瓣菜和再力花有优先吸收铵态氮的趋势。     

Enantiomeric and mesomeric mandelate complexes of molybdenum -- on their stereospecific formations and absolute configurations

The stereospecific formation and absolute configuration of R-homocitrate coordinated FeMo-co in nitrogenase was mimicked through the structural analyses of a collection of enantiomeric and mesomeric mandelato molybdenum complexes, i.e., (NH(4))(2)[Mo(Delta)O(2)(R-mand)(2)]x3H(2)O (1a), (NH(4))(2)[Mo(Lambda)O(2)(S-mand)(2)]x3H(2)O (1b), (NH(4))(4)[Mo(Delta)O(2)(RS-mand)(2)][Mo(Lambda)O(2)(RS-mand)(2)]x8H(2)O (2), (NH(4))(2)[W(Delta)O(2)(R-mand)(2)]x2H(2)O (3a), (NH(4))(2)[W(Lambda)O(2)(S-mand)(2)]x2H(2)O (3b) (H(2)mand=mandelic acid, C(8)H(8)O(3)), which have been characterized by elemental analyses, optical rotation, circular dichroism, IR, NMR spectroscopes and X-ray single crystal studies. The R and S chiral mandelic acids induce the formations of the enantiomeric pair of chiral complexes, which are supported by the characterizations of optical rotation and circular dichroism. The configuration of the resulted metal center could be assigned as Delta or Lambda. While the RS racemic reagent yields only mesomeric compound. The Delta(R,R)-complexes 1a and 3a are enantiomers of Lambda(S,S)-1b and 3b, respectively. Of the five complexes, Mo and W atoms are all hexa-coordinated by two cis-oxo groups and two bidentate mandelate ligands through the deprotonated alpha-alkoxyl and alpha-carboxyl groups, forming a stable five-membered chelated rings. The average Mo(VI)-O bond distances with alpha-alkoxyl and alpha-carboxyl are 1.944 and 2.210 A, respectively. Further comparison indicates that bonds of alpha-alkoxyl groups in the hydroxycarboxylato molybdenum complexes are much sensitive to the change in the oxidation state of molybdenum, which support the possible Mo activation model in FeMo-co through the protonation and cleavage of alpha-alkoxyl group in homocitrate ligand.     

太湖地区氮素湿沉降动态及生态学意义：以常熟生态站为例

在常熟生态站2001年6月至2003年5月连续两年定位收集湿沉降,对太湖地区氮素湿沉降动态进行研究．结果表明,湿沉降氮输入量季节变化显著,夏、春季高,秋、冬季低．在湿沉降输入氮中NH4^+-N、NO3^--N和DON的比例分别为47．6％、35．1％和17．4％．湿沉降中NH4^+-N主要来自当地农田的氨挥发,湿沉降NH4^+-N月输入量随月降雨量增加而增加(R0=0．3178^**)．该地区空气中NO3^--N浓度相对比较稳定,湿沉降中NO3^--N浓度与降雨量呈负相关(R^2=0．4205^***)．湿沉降NO33^--N月输入量与月降雨次数呈直线正相关(R^2=0．6757***),而与月降雨量相关性较差(R^2=0．1985^*)．湿沉降TN年输入量为27．0kg·hm^-2,并在所有降雨中,氮浓度均超过水体富营养化阈值(0．2mg·L^-1)．     

Tuning mesomorphic properties and handedness of chiral calamitic liquid crystals by minimal modification of the effective core

Two pairs of calamitic liquid crystalline molecules, (+)-2-[4'-(S)-sec-butoxyphenyl]-5-(4'-hexoxyphenyl)toluene ((+)-S-1) and (+)-2-(4'-hexoxyphenyl)-5-[4'-(S)-sec-butoxyphenyl]toluene ((+)-S-2), (-)-2-[4'-(R)-sec-butoxyphenyl]-5-(4'-hexoxyphenyl)toluene ((-)-R-1) and (-)-2-(4'-hexoxyphenyl)-5-[4'-(R)-sec-butoxyphenyl]toluene ((-)-R-2), have been designed and synthesized. Each of the molecules consists of a p-terphenyl core substituted with a methyl group on the middle ring, a chiral sec-butoxy tail, and an achiral n-hexoxy tail. The geometrical difference between (+)-S-1 ((-)-R-1) and (+)-S-2 ((-)-R-2) lies only in the location of the methyl group on the effective mesogenic core. Yet, such a small change in the structure gives rise to remarkable differences in mesogenic properties and handedness. Both (+)-S-1 and (-)-R-1 have an enantiotropic cholesteric phase (N*) and a monotropic twist grain boundary C* phase (TGBC*), whereas (+)-S-2 and (-)-R-2 exhibit only a monotropic N* phase. Moreover, (+)-S-1 ((-)-R-1) and (+)-S-2 ((-)-R-2) have opposite handedness in the N* phase, and (+)-S-1 and (-)-R-1 even have a helical inversion from N* to TGBC* phase through a non-helical chiral mesophase.     

莴笋对不同形态氮素的反应

探讨了不同形态氮素对莴笋生长发育的影响及其营养特性。结果表明,莴笋幼苗根系对NH4^+ -N的亲和力稍大于NO3^- -N的亲和力;分别供给NO3^- -N+NO3^- -N及NH4^+ -N,莴笋的生物学产量和吸N量均依次递减（分别为100：56.9：12.4,100：48.9：8.6）,因此在水培条件下,NO3^- -N是最适合莴笋生长发育的氮源,NH4^+ -N与NO3^- -N各占50％时对莴笋的生长发育已有一定的抑制作用,仅以NH4^+ -N作氮源则莴笋很难生长;NH4^+ -N与NO3^- -N各占50％时,莴笋倾向于吸收较多的NH4^+ -N,而且在培养不同阶段NH4^+/NO3^-吸收比例均大于1,莴笋表现出喜铵性,但NH4^+ -N并非莴笋很适合的氮源;营养液中NO3^- -N不足,主要影响莴笋茎叶的生长,而NH4^+ -N所占比例达50％时,莴笋根系生长受到抑制,且有明显的受害症状;以NO3^- -N作氮源预培养两周,以含微量NO3^- -N的自来水为水源,再单独以NH4^+ -N为氮源,对莴笋生长有极大的促进作用,同时还大幅度降低了体内硝酸盐的含量。尿素作氮源莴笋未出现受害症状,但莴笋的生长发育状况明显劣于其它氮源。     

Versatile precursor to ruthenium-bis(phosphine) hydrogenation catalysts

The known complex trans-RuCl2(NBD)Py2 (1, NBD is norbornadiene, Py is pyridine) reacts with either (R)-BINAP ((R)-2, 2'-bis(diphenylphosphino)-1,1'-binaphthyl), (S;S)-Chiraphos ((2S;3S-(-)-2,3-bis(diphenylphosphino)butane), (S;S)-Skewphos ((2S;4S)-(-)-2,4-bis(diphenylphosphino)pentane), (R)-(S)-Josiphos ((R)-(-)-1-[(S)-2-(diphenylphosphino)ferrocenyl]ethyl-dicyclohexylpho sphine), (R;R)-Norphos ((2R;3R)-(-)-2, 3-bis(diphenylphosphino)bicyclo[2.2.1]hept-5-ene), or (R;R)-Me-DUPHOS ((-)-1,2-bis((2R;5R)-2, 5-dimethylphospholano)benzene) to generate in high yields the crystalline complexes trans-RuCl2(P-P*)Py2 (P-P* is the corresponding chiral bis(phosphine)). The complexes trans-RuCl2(P-P*)Py2 are active enantioselective hydrogenation catalysts for ketoesters and noncarboxylic olefins in the presence of small amounts of HBF4 (aq.). They are active for hydrogenation of carboxylic substrates in the presence of Et3N. Reaction of trans-RuCl2(P-P*)Py2 with (rac)-1,2-diphenylethylene-diamine (N-N*, either enantiomer) forms in good yields the corresponding compounds trans-RuCl2(P-P*)(N-N*). Representative hydrogenations with these catalysts are presented.     

华南赤红壤无机复合肥氮磷淋失特征

采用室内土柱淋溶模拟试验,研究了不同施肥水平下无机复合肥中氮和磷在华南赤红壤中的淋失特征.结果表明: 铵态氮、硝态氮和总氮淋失量均随施肥量增加而提高;肥料中氮的淋失率在36.8%～49.2%之间,总氮淋失量（y）与施肥量（x）之间的回归方程为y=0.3667x+66.483（R²=0.992）;铵态氮和总氮的淋失主要集中在前5次淋洗,硝态氮的淋失持续时间更长.施肥量对可溶性磷淋失量无显著影响,但颗粒磷和总磷淋失量均随施肥量增加呈上升趋势;肥料磷淋失率在0.002%～0.010%之间,总磷淋失量（y）与施肥量（x）之间的回归方程为y=7e^-5x+0.0538（R²=0.931）;磷的淋失动态与氮显著不同,为缓慢的持续累积过程.硝态氮与铵态氮淋失量比值和可溶性磷与颗粒磷淋失量比值均随施肥量增加呈下降趋势.     

Increased tumor necrosis factor-alpha and nitric oxide production by rat macrophages following in vitro stimulation and intravenous administration of the delta-opioid agonist SNC 80

Opioids alter immune function by binding to opioid receptors on cells of the immune system, or indirectly by acting on receptors within the central nervous system. Mu-selective opioid agonists are generally associated with immunosuppression, whereas delta-opioid receptor-selective agonists are commonly associated with immunopotentiation. We have previously shown that intracerebroventricular administration of the nonpeptide delta-opioid receptor agonist (+)-4-((alpha R)-alpha-((2S, 5R)-4-allyl-2, 5-dimethyl-1-piperazinyl)-3-methoxybenzyl)-N, N-diethyl-benzamide (SNC 80) did not alter certain parameters of immunocompetence. In the present study, we studied the in vitro and ex vivo effects of SNC 80 on rat macrophage and lymphocyte functions. We showed that SNC 80 at concentrations of 10(-7) M and 10(-6) M, significantly (P < 0.01) stimulated the in vitro production of tumor necrosis factor-alpha (TNF-alpha) (60-100% increase) and nitric oxide (34-67% increase) by resident and LPS-stimulated peritoneal macrophages. Similarly, intravenous administration of SNC 80 (6.8 mg/kg) significantly (P < 0.01) increased the production of TNF-alpha and nitric oxide (2- and 1.5-fold increases respectively, compared with saline-injected control) by LPS-stimulated splenic macrophages. In addition, intravenous injection of SNC 80 plus Con A potentiated ex vivo LPS-stimulated macrophage functions. SNC 80 could potentially be utilized in various clinical situations where immunosuppression is undesirable.     

有机酸去除污泥重金属前后硝态氮和铵态氮浓度变化

研究了柠檬酸、草酸和乙酸溶液对污泥中重金属(Cd、Pb、Cu和Zn)的去除效果,以及处理前后析出液和污泥中硝态氮和铵态氮的浓度变化.结果表明,0.8mol.L-1柠檬酸溶液可去除污泥中76.0%的Pb和92.5%的Zn,是较好的重金属去除剂.污泥经有机酸处理后,有大量的硝态氮和铵态氮溶解于析出液中,与加入蒸馏水的对照处理相比,有机酸可大幅度增加析出液中铵态氮的含量,减少硝态氮含量.由于污泥处理过程中有其他形态的氮的转化,处理后污泥中仍含有较高浓度的硝态氮和铵态氮.0.5mol.L-1草酸处理的析出液中硝态氮和铵态氮浓度分别为2.8和888.1mg.L-1,且重金属含量不高,可作为较好的液体肥料进行回收利用.     

Physico-chemical method for ammonia removal from synthetic wastewater using limestone and GAC in batch and column studies

The purpose of the present study was to examine the removal of ammoniacal nitrogen (NH4-N) from synthetic wastewater using limestone (LS) and granular activated carbon (GAC) mixture as low cost adsorbent. In batch study, optimum shaking and settling times were 150 and 120 min, respectively. The LS-GAC mixture ratio of 25:15 removed about 58% NH4-N. The smaller particle size of medium yielded higher adsorption capacity. The equilibrium adsorption data followed the Freundlich isotherm (R2 > 0.98) but it showed weak bond. Adsorption kinetics were well described by the pseudo second-order rate model (R2 > 0.93). The upflow column showed that higher flow rate and initial concentration resulted in shorter column saturation time. The study showed that the usage of GAC could be reduced by combining GAC with LS for the removal of NH4-N from wastewater; thus reducing the cost of treatment.     

Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting

Nitrification involves the sequential biological oxidation of reduced nitrogen species such as ammonium-nitrogen (NH(4)(+)-N) to nitrite-nitrogen (NO(2)(-)-N) and nitrate-nitrogen (NO(3)(-)-N). The adequacy of modeling NH(4)(+)-N to NO(3)(-)-N oxidation as one composite biochemical reaction was examined at different relative dynamics of NH(4)(+)-N to NO(2)(-)-N and NO(2)(-)-N to NO(3)(-)-N oxidation. NH(4)(+)-N to NO(2)(-)-N oxidation and NO(2)(-)-N to NO(3)(-)-N oxidation by a mixed nitrifying consortium were uncoupled using selective inhibitors allylthiourea and sodium azide. The kinetic parameters of NH(4)(+)-N to NO(2)(-)-N oxidation (q(max,ns) and K(S,ns)) and NO(2)(-)-N to NO(3)(-)-N oxidation (q(max,nb) and K(S,nb)) were determined by a rapid extant respirometric technique. The stoichiometric coefficients relating nitrogen removal, oxygen uptake and biomass synthesis were derived from an electron balanced equation. NH(4)(+)-N to NO(2)(-)-N oxidation was not affected by NO(2)(-)-N concentrations up to 100 mg NO(2)(-)-N L(-1). NO(2)(-)-N to NO(3)(-)-N oxidation was noncompetitively inhibited by NH(4)(+)-N but was not inhibited by NO(3)(-)-N concentrations up to 250 mg NO(3)(-)-N L(-1). When NH(4)(+)-N to NO(2)(-)-N oxidation was the sole rate-limiting step, complete NH(4)(+)-N to NO(3)(-)-N oxidation was adequately modeled as one composite process. However, when NH(4)(+)-N to NO(2)(-)-N oxidation and NO(2)(-)-N to NO(3)(-)-N oxidation were both rate limiting, the estimated lumped kinetic parameter estimates describing NH(4)(+)-N to NO(3)(-)-N oxidation were unrealistically high and correlated. These findings indicate that the use of single-step models to describe batch NH(4)(+) oxidation yields erroneous kinetic parameters when NH(4)(+)-to-NO(2)(-) oxidation is not the sole rate-limiting process throughout the assay. Under such circumstances, it is necessary to quantify NH(4)(+)-N to NO(2)(-)-N oxidation and NO(2)(-)-N to NO(3)(-)-N oxidation, independently.     

Optical resolution of β-lactams on 1-phenylethylcarbamates of cellulose and amylose

Optical resolution of six β-lactams was examined by HPLC using chiral stationary phases consisting of tris((R)-, (RS)-, and (S)-1-phenylethylcarbamate)s of cellulose and amylose. All β-lactams were optically resolved at least by one of the carbamates. Amylose tris((S)-1-phenylethylcarbamate) showed high optical resolving abilities for some β-lactams.     

Improvement of water solubility of non-competitive AMPA receptor antagonists by complexation with beta-cyclodextrin

The (R,S)-2-acetyl-1-(4'-chlorophenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline ((R,S)-1) was previously identified as a potent non-competitive AMPA receptor antagonist able to prevent epileptic seizures and reduce AMPA-induced current in electrophysiological experiments. Through the enantiomeric resolution of racemate by chiral HPLC we already demonstrated that the (R)-1 enantiomer was the eutomer. Considering the poor water solubility, these compounds have been complexed with beta-cyclodextrin (beta-CyD). The effect of beta-cyclodextrin on the spectral features of molecules was quantitatively investigated, in fully aqueous medium by phase-solubility study and the obtained diagrams suggested that it forms complexes with a molar ratio 1:1. The binding constant (K((R)-1)=15889M(-1), K((R,S)(-1))=1079 M(-1)) and the complexation efficiency (CE) were calculated. Then the solid complexes in 1:1 molar ratio were prepared by the co-precipitation method and the FTIR-ATR measurements were carried out in order to confirm the host-guest interactions that drive the complexation process, by monitoring the significant differences of the spectra of the complexes with respect to those of the corresponding physical mixtures in the same molar ratio. The experimental data have been compared with molecular modelling studies and we confirmed our hypothesis.     

施加外源烯土元素对土壤中氮形态转化和有效性的影响

通过温室土培试验,测定了施加不同剂量农用稀土微肥（常乐）后不同采样时间的土壤有效N－NH^ 4-N,NO^-3,N含量和土壤脲酶活性,结果表明,当外源烯土施入量较大时,土壤有效N和NH^ 4-N含量明显降低,而土壤NO^-3的变化不显著,根据化学品安全性评价方法,实验确定外源稀土对土壤NH^ 4-N和有效N浓度影响的无观察效应浓度（NOEC）应为5mg.kg^-1风干土,实验观察到土壤NH^ 4-N含量的降低与土壤脲酶活性的抑制之间有较好的相关性（R^2=0.87),外源稀土对土壤N形态转化和有效性产生影响的主要原因之一,是外源稀土施放量较高时抑制了土壤脲酶参与下的氨化作用,土壤生态系统可以通过自适应过程进行自我调节,恢复N供给的能力。     

好氧颗粒污泥对不同底物组成的响应

在序批式间歇反应器（R1、R2和R3）中,采用乙酸钠（R1）、蔗糖（R2）和苯酚（R3）三种不同基质作为碳源,均成功地培养出了好氧颗粒污泥;考察了不同颗粒污泥的理化性质及其对污染物的转化能力。结果表明,R1中颗粒污泥外观呈黄色,其主要的微生物菌群为细菌;R2中颗粒污泥外观呈黑色,内部含有丝状菌;而R3中颗粒污泥表面被大量丝状菌包裹,颗粒污泥呈淡黄色。在进水COD1000mg／L时R1、R2和R3中颗粒污泥比有机物的利用速率大小顺序为R3〉R1〉R2,而COD的去除率顺序却为R2〉R1〉R3。在进水氨氮40mg／L时,R1、R2和R3中氨氮的去除率分别在91％、96％和80％以上。以不同的底物培养出不同的好氧颗粒污泥可以拓展其在有毒化学物质如酚类化合物和高浓度工业废水生物处理中的应用。