Radiological insights into rheumatoid meningitis - a rare central nervous system manifestation of rheumatoid arthritis: a retrospective review of six cases.

BACKGROUND: The objective is to analyze and review the clinical, laboratory, and neuroimaging characteristics of rheumatoid meningitis (RM) in six patients with known rheumatoid arthritis (RA). METHODS: We performed a retrospective review of patients diagnosed with RM from August 2012 to June 2023. To identify the cases, we used medical term search engines and the hospital´s radiology case database. Clinical information and laboratory findings were gathered from the medical records. A neuroradiologist with five years of experience reviewed and analyzed the RM to determine the characteristics findings of RM. RESULTS: Six patients with RM are included. Seizures along with headaches were among the clinical signs that were documented. All the patients had high levels of rheumatoid factor (RF) and anti-cyclic citrullinated peptides (ACPA) in the peripheral blood. Biopsy in two cases confirmed typical rheumatoid nodules. Leptomeningeal enhancement was found bilaterally in all cases and was predominantly found in the frontoparietal region. "Mismatch DWI/FLAIR" was found in five patients. Bilateral subdural collections could be found in two patients. Brain PET scan revealed increased metabolism in two cases. CONCLUSION: Rheumatoid meningitis is a rare complication of rheumatoid arthritis (RA) with challenging clinical diagnosis due to non-specific symptoms. This study highlights the importance of MR in detecting characteristic neuroimaging patterns, including "mismatch DWI/FLAIR", to aid in early diagnosis. Increased awareness of this condition may facilitate timely intervention and improve prognosis. These results still need to be verified by large studies.

Intestinal anisakiasis: CT imaging findings-a 10-year descriptive study in a single center.

PURPOSE: The aim of this study was to retrospectively review cases of intestinal anisakiasis diagnosed by CT over a 10-year period and to evaluate imaging findings associated with the disease. METHODS: This retrospective study included 71 patients with clinical suspicion of intestinal anisakiasis in whom an abdominopelvic computed tomography (CT) was performed at a single institution between June 2011 and December 2021. To identify the cases, we used medical term search engines and the hospital's radiology case database. Clinical information was gathered from the medical records. A radiologist with five years of experience reviewed and analyzed the CT images to determine the characteristic findings of intestinal anisakiasis. RESULTS: The study included 47 confirmed cases of intestinal anisakiasis. The mean age of the patients was 52 years (range 18-87 years), being more frequent in men than women (26:21). All patients reported ingestion of raw fish, most commonly anchovies in vinegar (30/47, 63,8%). Abdominal pain was the predominant symptom, accompanied by nausea, vomiting, and occasionally fever. The most common clinical suspicions were intestinal obstruction (14/47, 29,8%) and appendicitis (10/47, 21,3%), whereas intestinal anisakiasis was suspected in only 2 cases prior to imaging. CT showed thickening of the bowel wall with submucosal edema in all patients, predominantly involving the ileum (43/47, 91,5%), usually in a relatively long segment (mean of 17,5 cm, range 10-30 cm). Simultaneous involvement of multiple bowel segments was observed in 16 cases (34%). Intestinal obstruction with dilatation of proximal loops (33/47, 70,2%), ascites (45/47, 95,7%), and mesenteric fat striation (32/47, 68,1%) were also common findings. CONCLUSION: This study demonstrates the value of computed tomography in suggesting the diagnosis of intestinal anisakiasis, which often presents with nonspecific clinical manifestations. The characteristic CT findings that provide diagnostic clues are bowel wall thickening with submucosal edema, typically involving a long segment of the ileum, with signs of intestinal obstruction, ascites, and mesenteric fat striation. Simultaneous involvement of several intestinal segments (typically the gastric antrum and right colon) is an additional finding to be considered and may provide a diagnostic clue.

How to Regulate the Migration Ability of Emulsions in Micro-Scale Pores: Droplet Size or Membrane Strength?

Micro visualization has become an important means of solving colloid and interface scientific problems in enhanced oil recovery. It can establish a relationship between a series of performance evaluations of an oil-water interface under macroscopic dimensions and the actual application effect in confined space, and more truly and reliably reflect the starting and migration behavior of crude oil or emulsion in rock pores. In this article, zwitterionic surfactant alkyl sulfobetaine (ASB) and anionic extended surfactant alkyl polyoxypropylene sulfate (A145) were employed as flooding surfactants. The macroscopic properties of the surfactant solutions, such as the oil-water interfacial tension (IFT), the interfacial dilational rheology and the viscosity of crude oil emulsions, have been measured. At the same time, we link these parameters with the oil displacement effect in several visual glass models and confirm the main factors affecting the migration ability of emulsions in micro-scale pores. The experimental results show that ASB reduces the IFT through mixed adsorption with crude oil fractions. The flat arrangement of the large hydrophilic group of ASB molecules enhances the interactions between the surfactant molecules on the oil-water interface. Compared with sulfate, betaine has higher interfacial membrane strength and emulsion viscosity. A145 has a strong ability to reduce the IFT against crude oil because of the larger size effect of the PO chains at the oil side of the interface. However, the membrane strength of A145 is moderate and the emulsion does not show a viscosity-increasing effect. During the displacement process, the deformation ability of the front emulsions or oil banks is the main controlling factor of the displacement efficiency, which is determined by the membrane strength and emulsion viscosity. The strong interfacial membrane strength and the high emulsion viscosity are not conducive to the migration of droplets in pore throats and may result in low displacement efficiency.

The Synergistic Effects between Sulfobetaine and Hydrophobically Modified Polyacrylamide on Properties Related to Enhanced Oil Recovery.

In order to explore the mechanism responsible for the interactions in the surfactant-polymer composite flooding and broaden the application range of the binary system in heterogeneous oil reservoirs, in this paper, the influences of different surfactants on the viscosity of two polymers with similar molecular weights, partially hydrolyzed polyacrylamide (HPAM) and hydrophobically modified polyacrylamide (HMPAM), were studied at different reservoir environments. In addition, the relationship between the surfactant-polymer synergistic effects and oil displacement efficiency was also investigated. The experimental results show that for HPAM, surfactants mainly act as an electrolyte to reduce its viscosity. For HMPAM, SDBS and TX-100 will form aggregates with the hydrophobic blocks of polymer molecules, reducing the bulk viscosity. However, zwitterionic surfactant aralkyl substituted alkyl sulfobetaine BSB molecules can build "bridges" between different polymer molecules through hydrogen bonding and electrostatic interaction. After forming aggregates with HMPAM molecules, the viscosity will increase. The presence of two polymers all weakened the surfactant oil-water interfacial membrane strength to a certain extent, but had little effect on the interfacial tension. The synergistic effect of the "bridge" between HMPAM and BSB under macroscopic conditions also occurs in the microscopic pores of the core, which has a beneficial effect on improving oil recovery.

Dynamic Interfacial Tensions of Surfactant and Polymer Solutions Related to High-Temperature and High-Salinity Reservoir.

Betaine is a new surfactant with good application prospects in high-temperature and high-salinity reservoirs. The interfacial properties of two kinds of betaine mixtures with a good synergistic effect were evaluated in this paper. On this basis, the effects of temperature-resistant, salt-resistant polymers with different contents of 2-acrylamide-2-methylpropanesulfonic acid (AMPS) on dynamic interfacial tensions (IFTs) against n-alkanes and crude oil were studied. The experimental results show that the IFTs between betaine ASB and n-alkanes can be reduced to ultra-low values by compounding with anionic surfactant petroleum sulfonate (PS) and extended anionic surfactant alkoxyethylene carboxylate (AEC), respectively. ASB@AEC is very oil-soluble with nmin value ≥14, and ASB@PS is relatively water-soluble with nmin value of 10. The water solubility of both ASB@PS and ASB@AEC is enhanced by the addition of water-soluble polymers. The HLB of the ASB@AEC solution becomes better against crude oil after the addition of polymers, and the IFT decreases to an ultra-low value as a result. On the contrary, the antagonistic effect in reducing the IFT can be observed for ASB@PS in the same case. In a word, polymers affect the IFTs of surfactant solutions by regulating the HLB.

Chiral Supramolecular Microporous Thio-Oxomolybdenum(V) Tartrates for the Selective Adsorptions of Gases.

Two pairs of enantiomerically pure hexanuclear and tetranuclear microporous molybdenum(V) d/l-tartrates, (H2trz)3[Mo6O6(µ2-O)3(µ2-S)3(d/l-Htart)3(Htrz)6]·8H2O (abbreviated as d-1 and l-1; H4tart = tartaric acid, Htrz = 1,2,4-triazole) and (H22-mim)8[Mo4O4(µ2-S)4(d/l-tart)2]2·4H2O (d-2/l-2; H2-mim = 2-methylimidazole), have been isolated in reduced media and well characterized. These enantiomers are observed to finish self-assemblies with single chiral configurations. Structural analyses indicate that tartrates adopt different coordination modes with α-carboxy and/or α-alkoxy groups in 1 and 2, which are further completed with nitrogen-containing ligands. There are two types of micropores that exist in 1 and 2, separately, which are all formed by the isolated molecules themselves. The significant roles of hydrogen bonding among lattice molecules, tartrates, and multi-azoles are suggested, where 1 and 2 exhibited interesting supramolecular networks only through intramolecular self-sorts. Adsorption tests show that 1 has good affinities toward CO2 and O2, while 2 is the most potential O2 adsorbent compared with other common gases CO2, H2, CH4, and N2 under different pressures. In addition, IR, UV-vis, CD (circular dichroism), and solid-state 13C NMR spectroscopies have demonstrated the special chemical properties of these novel molybdenum d/l-tartrates.

Traumatic arterial injuries in upper and lower limbs: what every radiologist should know.

Traumatic arterial injuries of the extremities are a rare but potentially fatal event. Computed tomography (CT) angiography of the extremities has become the technique of choice and can provide rapid accurate detection and characterization of vascular lesions. Vascular injuries can be classified in active hemorrhage, vasospasm, occlusion, post-traumatic arteriovenous fistula, pseudoaneurysm, and patterns of intimal injuries. The learning objectives of this pictorial essay are to review the normal arterial anatomy of the upper and lower limbs, describe the technique of CT angiography in vascular trauma of the extremities, describe and illustrate the CT-angiography findings of traumatic arterial injuries, and know the potential pitfalls when interpreting a CT-angiography of the extremities.

Intrinsic Molybdenum-Based POMOFs with Impressive Gas Adsorptions and Photochromism.

Novel molybdenum(VI/V) POM-based self-constructed frameworks [MoVI 12 O24 (µ2 -O)12 (trz)6 (H2 O)6 ] ⋅ 6Hma ⋅ 18H2 O (1, Htrz=1H-1,2,3-triazole, ma=methylamine), [MoVI 7 O14 (µ2 -O)8 (trz)5 (H2 O)] ⋅ 7Hma ⋅ 5H2 O (2), Na3 [MoV 6 O6 (µ2 -O)9 (Htrz)3 (trz)3 ] ⋅ 7.5H2 O (3) and [MoV 8 O8 (µ2 -O)12 (Htrz)8 ] ⋅ 30H2 O (4) have been covalently decorated with tri-coordinated deprotonated/protonated 1,2,3-triazoles. Channels with an inner diameter of 7.5 Šwere found in 1, whereas a tunnel composed of stacking molecules with an inner diameter of 4.1 Šalong the b-axis exists in 2; it is occupied by free disordered methylamines, showing selective adsorption of O2 and CO2 at 25 °C. Obvious downfield shifts were observed by 13 C NMR spectroscopies for methylamines inside the confined channels in 1 and 2. There are diversified pores in 3 and 4, which are formed by the molecules themselves and intermolecular accumulations. Adsorption tests indicate that 3 and 4 are fine adsorption materials for CH4 and CO2 under low pressure that rely on the environments built by the POMs. Correspondingly, 1 and 2 display reversible photoresponsive thermochromism that is subtlety influenced by the channels. The polyoxometalate organic frameworks (POMOFs) with multiple functional adsorptions are easy to assemble. Their photo-/thermoresponse properties offer a new pathway for the self-constructions of one-off hybrid materials that possess the good properties of both POMs and MOFs.

Adsorption and wettability of extended anionic surfactants with different PO numbers on a polymethylmethacrylate surface.

To investigate the effect of the number of propylene oxide (PO) units on the wettability of surfactants, the wettability of isomeric dodecyl(polyoxyisopropyl)7 sulfate (S-C12PO7S) and isomeric dodecyl(polyoxyisopropyl)13 sulfate (S-C12PO13S) on the surface of polymethylmethacrylate (PMMA) was investigated. The adsorption behavior on the PMMA surface was analyzed by measuring the surface tension and the contact angle. It is found that the PO group may form hydrogen bonds with the PMMA surface, thus facilitating the hydrophobic tails pointing to the aqueous phase. Moreover, the steric effect of the PO group benefits the formation of semi-micelles above the critical micelle concentration (CMC). Surfactant molecules adsorb on the PMMA surface by polar adsorption below the CMC with hydrophobic tails towards the water. Therefore, the PMMA surface is modified to be more hydrophobic. However, the sodium dodecyl sulfate (SDS) surfactant with no PO unit does not have hydrophobic modification ability on the PMMA surface. Below the CMC, the adsorption amounts of the S-C12PO7S and S-C12PO13S surfactants at the solid-liquid interface were approximately 1/3 of those at the air-liquid interface. Interestingly, the adsorption behavior changes when the concentration of the surfactants is around the CMC. The hydrophilic heads of the surfactant molecules will point to water, and the surfactant molecules will form semi-micellar aggregates on the PMMA surface. Therefore, the PMMA surface is modified to be hydrophilic above the CMC. What's more, both the hydrophilic modification ability and hydrophobic modification ability of the S-C12PO13S surfactant are stronger than those of the S-C12PO7S surfactant. This means that the number of PO units will affect the wettability ability of the surfactants. Therefore, the S-C12PO13S surfactant possesses smaller contact angles than the S-C12PO7S surfactant at high concentrations.

Adsorption behaviors of branched cationic gemini surfactants and wettability in quartz-solution-air systems.

The adsorption and wetting on quartz surfaces by aqueous solutions of xylyl-substituted biquaternary ammonium salt gemini surfactants with different spacer groups (C3 and C6), have been investigated. The interfacial properties of surfactant solutions such as contact angle, adhesional tension (γLV cos θ), quartz-water interfacial tension (γSL) as well as adhesion work (WA) have been estimated. The obtained results show that C3 and C6 have similar adsorption behavior on quartz surfaces. Before critical micelle concentration (cmc) is reached, the contact angles of gemini surfactants slowly increase with the increasing concentration, and the adsorption amount at the water-air interface is almost the same as those at a quartz-water interface. After reaching cmc, the gemini surfactant Cn molecules form a more compact adsorption film through bending the flexible spacer chain, instead of forming a bi-layer. As a result, a further increase in quartz-liquid interfacial tension (γSL) and a consequent increase in contact angle have been observed after cmc. Gemini C6 shows a stronger ability towards hydrophobic modification at a quartz surface than C3, demonstrating the contribution of the longer methylene spacer to the hydrophobic modification of the quartz surface.

Isolated Mixed-Valence Iron Vanadium Malate and Its Metal Hydrates (M = Fe2+, Cu2+, Zn2+) with Reversible and Irreversible Adsorptions for Oxygen.

Isolated octanuclear iron-vanadium malate (NH4)3(CH3NH3)3[FeIII2VIV2VV4O11(mal)6]·7.5H2O (1; H3mal = malic acid) and its family of metal hydrates M'3n[MII(H2O)2]1.5n[FeIII2VIV2VV4O11(mal)6]n·xnH2O (2 or 2-Fe, M' = NH4+, M = Fe, x = 7.5; 3 or 3-Cu, M' = K+, M = Cu, x = 10; 4 or 4-Zn, M' = K+, M = Zn, x = 6.5) have been obtained by self-assembly in water. The cluster anion [Fe2V6O11(mal)6]6- (1a) shows an interesting iron bicapped-triangular-prismatic structure, which is bridged by M2+ hydrates (M = Fe, Cu, Zn) to construct isostructural metal organic frameworks (MOFs) 2-4. The mixed-valence vanadium systems in 1-4 were determined by theoretical bond valence calculations (BVS) and charge balance. The magnetic susceptibilities are further elucidated as high spin for Fe3+ in 1a and bridging Fe2+ in 2-Fe, respectively. A strong ferromagnetic interaction was also observed for 2-Fe at 3 K. 2-Fe, 3-Cu, and 4-Zn have similar hydrophilic channels with diameters of 6.8, 6.5, and 6.6 Å, respectively, which show obvious affinity for O2 in comparison with no adsorption of N2, H2, CO2, and CH4 at room temperature under different pressures. Moreover, 2-Fe and 4-Zn exhibit irreversible O2 absorptions, which may be attributed to charge transfer between O2 and open metal sites (OMSs) formed during vacuum heating pretreatment. UV-vis and EPR spectra show a change in electronic structure of 2-Fe after O2 adsorption. The reversible adsorption observed in 3-Cu suggests a weak interaction between O2 and Cu2+ due to the Jahn-Teller effect. The properties of gas adsorption provide an insight into the performances of small molecules in the channels constructed by synthetic octanuclear model compounds, which are related to the interactions between the gas substrate and the heterometal cluster in biology.

Gas Adsorption of Mixed-Valence Trinuclear Oxothiomolybdenum Glycolates.

Trinuclear oxothiomolybdenum(IV) glycolates (H2glyc, glycolic acid) with 2-methylimidazole (2-mim), 4-methylimidazole (4-mim), and sulfite, Na2[MoIV3(µ3-S)(µ2-O)3(glyc)3(2-mim)3]·1.5H2O (1), (4-Hmim)6[MoIV3(µ3-S)(µ2-O)3(glyc)3(4-mim)3]2[MoVIO2(glyc)2] (2), and Na3(4-Hmim)[MoIV3(µ3-S)(µ2-O)3(SO3)(glyc)3(4-mim)]·8H2O (3), have been isolated in reduced media, where 4-methylimidazole trinuclear oxothiomolybdenum(IV) glycolates in 2 coprecipitate with dioxomolybdenum(VI) glycolate, exhibiting unusual mixed valences of 4+ and 6+. Large downfield shifts of glycolates have been observed in solid-state and solution 13C (1H) NMR spectra with coordination to Mo, indicating obvious dissociation of soluble 1 and 3 in solution. Investigations of the coordination modes and conversions among the three complexes give insight into the reactivities of trinuclear oxothiomolybdenum(IV) complexes. Channels with 3.1 × 7.0 Å2 diameters exist in 2, showing reversible O2 absorption of 65.03 mg at 29.9 bar compared with little or no adsorption of N2, H2, CO2, and CH4 at room temperature, respectively. Moreover, trinuclear 2- or 4-methylimidazole oxothiomolybdenum(IV) glycolates 1 and 3 show only a few adsorptions for O2 under the same conditions.

2-Methylimidazole Copper Iminodiacetates for the Adsorption of Oxygen and Catalytic Oxidation of Cyclohexane.

The mixed-ligand copper(II) iminodiacetates [Cu(ida)(2-mim)(H2O)2]·H2O (1), [Cu(ida)(2-mim)2]·2H2O (2), [Cu(ida)(2-mim)(H2O)]n·4.5nH2O (3), and [Cu2(ida)2(2-mim)2]n·nH2O (4) (H2ida = iminodiacetic acid, 2-mim = 2-methylimidazole) were obtained from neutral or alkaline solutions at different temperatures. The novel complex 4 contains very small holes with diameters of 2.9 Å, which can adsorb O2 selectively and reversibly between 1.89 to 29.90 bars, compared with the different gases of N2, H2, CO2, and CH4. This complex is stable up to 150 °C based on thermal analyses and XRD patterns. The four complexes show catalytic activities that facilitate the conversion of cyclohexane to cyclohexanol and cyclohexanone with hydrogen peroxide in a solution. The total conversion is 31% for 4.

Wetting of polymer surfaces by aqueous solutions of branched cationic Gemini surfactants.

The adsorption of xylyl-substituted biquaternary ammonium salt Gemini surfactants with different spacer (C3 and C6) at polytetrafluoroethylene (PTFE) and polymethylmethacrylate (PMMA) surfaces has been investigated and the different adsorption parameters such as surface tension, contact angle, adhesional tension, solid-water interfacial tension and work of adhesion have been estimated. The results show that C3 and C6 have similar adsorption behaviors at PTFE and PMMA surfaces. C3 and C6 adsorb gradually at a PFTE-water interface via hydrophobic interactions and the adsorption amounts at the water-air interface are almost three times higher than those at the PTFE-water interface due to the steric hindrance effect. However, the contact angle keeps constant throughout the experimental concentration range because the decrease in surface tension just counterbalances the decrease in PFTE-water interfacial tension. On the other hand, C3 and C6 adsorb at the PMMA surface via polar interactions between xylyl and functional groups of PMMA before CMC. Similar to PTFE, the increase in PMMA-water interfacial tension compensates the decrease in surface tension and the contact angle also shows a stationary value before the CMC. A bi-layer structure of C3 and C6 will be formed at the PMMA-water interface via hydrophobic interaction and PMMA-water interfacial tension decreases consequently after the CMC, which results in the decrease in contact angle.

Preliminary Assignment of Protonated and Deprotonated Homocitrates in Extracted FeMo-Cofactors by Comparisons with Molybdenum(IV) Lactates and Oxidovanadium Glycolates.

A similar pair of protonated and deprotonated mononuclear oxidovanadium glycolates [VO(Hglyc)(phen)(H2O)]Cl·2H2O (1) and [VO(glyc)(bpy)(H2O)] (2) and a mixed-(de)protonated oxidovanadium triglycolate (NH4)2[VO(Hglyc)2(glyc)]·H2O (3) were isolated and examined. The ≡C-O(H) (≡C-OH or ≡C-O) groups coordinated to vanadium were spectroscopically and structurally identified. The glycolate in 1 features a bidentate chelation through protonated α-hydroxy and α-carboxy groups, whereas the glycolate in 2 coordinates through deprotonated α-alkoxy and α-carboxy groups. The glycolates in 3 coordinate to vanadium through α-alkoxy or α-hydroxy and α-carboxy groups and thus have both protonated ≡C-OH and deprotonated ≡C-O bonds simultaneously. Structural investigations revealed that the longer protonated V-Oα-hydroxy bonds [2.234(2) Å and 2.244(2) Å] in 1 and 3 are close to those of FeV-cofactor (FeV-co) 2.17 Å1 (FeMo-co 2.17 Å2), while deprotonated V-Oα-alkoxy bonds [2, 1.930(2); 3, 1.927(2) Å] were obviously shorter. This shows a similar elongated trend as the Mo-O distances in the previously reported deprotonated vs protonated molybdenum lactates (Wang, S. Y. et al. Dalton Trans. 2018, 47, 7412-7421) and these vanadium and molybdenum complexes have the same local V/Mo-homocitrate structures as those of FeV/Mo-cos of nitrogenases. The IR spectra of these oxidovanadium and the previously synthesized molybdenum complexes including different substituted ≡C-O(H) model compounds show red-shifts for ≡C-OH vs ≡C-O alternation, which further assign the two IR bands of extracted FeMo-co at 1084 and 1031 cm-1 to ≡C-O and ≡C-OH vibrations, respectively. Although the structural data or IR spectra for some of the previously synthesized Mo/V complexes and extracted FeMo-co were measured earlier, this is the first time that the ≡C-O(H) coordinated peaks are assigned. The overall structural and IR results well suggest the coexistence of homocitrates coordinated with α-alkoxy (deprotonated) and α-hydroxy (protonated) groups in the extracted FeMo-co.

Effects of Calcium Ions on the Solubility and Rheological Behavior of a C22-Tailed Hydroxyl Sulfobetaine Surfactant in Aqueous Solution.

Effects of calcium ions (Ca2+) on the solubility, aggregate structure, and rheological behavior of a C22-tailed zwitterionic surfactant, erucyl dimethyl amidopropyl hydroxyl sulfobetaine (EHSB), have been investigated in aqueous solution. In comparison with sodium ions (Na+), Ca2+ ions exhibit a much higher efficiency in decreasing the Krafft temperature (TK) of EHSB. Specifically, contrary to Na+ ions which have no obvious effect on the rheological properties of the EHSB solution, Ca2+ ions increase the viscosity of the EHSB solution at lower EHSB concentration, and enhance its elasticity at higher EHSB concentration. Moreover, Ca2+ ions raise the temperature needed for the elastic-to-viscous transition of the EHSB solution at higher concentration. At lower EHSB concentration, the hydrophobic interaction between the ultralong hydrocarbon chains induces a tighter packing of the hydrophobic chains by forming a more stretched configuration, while at higher EHSB concentration, the electrostatic attraction between Ca2+ ions and the sulfonate groups of EHSB induces a tighter packing of the headgroups by forming Ca2+-mediated bridges among the EHSB headgroups. Besides, the above interactions may strengthen the hydrogen bonding of OH groups and/or of C═O amide groups, which in turn facilitates the compact packing of the surfactant molecules in aggregates and promotes the growth and entanglement of wormlike micelles. Thus, the EHSB solution shows Ca2+-dependent rheological behaviors. The solubility and rheological properties of the ultralong chain surfactant solution can be simultaneously improved with the addition of divalent Ca2+ ions.

Wheel-Like Icosanuclear Peroxotitanate-A Stable Water-Soluble Catalyst for Oxygen Transfer Reactions.

Water-soluble wheel-like icosanuclear peroxotitanate K16[Ti20(µ-O)8(HO2)8(O2)12( R, R-tart)12]·52H2O (1) chelated by tartrate has been successfully isolated. As the largest peroxotitanate reported, {Ti20} features 20 (hydro)peroxo groups with three kinds of coordination modes in µ-η1:η2, µ-η2:η2, and η2 fashions. The cluster is stable in solution and solid states. It has been tested for the catalytic oxidations of methyl phenyl sulfide and pyridine with hydrogen peroxide, respectively, which shows reversible elimination and the addition of peroxo groups. This provides a rare example of well-characterized titanium peroxide for homogeneous catalysis and mechanism research.

Stereodivergent synthesis of all the four stereoisomers of antidepressant reboxetine.

Chiral amino alcohol-copper(ii) catalysts Cu-L1c and Cu-ent-L1c were utilized to promote the diastereoselective nitroaldol reactions of chiral aldehydes (S)-3 or (R)-3 with nitromethane, which respectively led to the preferential formation of certain stereoisomer for nitro diol derivatives 4. Using this catalytic protocol, all the four stereoisomers of the antidepressant reboxetine were divergently prepared. The highest overall yield of this synthetic route reached up to 30.5% from aldehyde (S)-3.

Efficient synthesis of chiral benzofuryl ß-amino alcohols via a catalytic asymmetric Henry reaction.

Chiral ß-amino alcohol ligands were found effective for the copper(ii)-catalyzed asymmetric Henry reaction of benzofuran-2-carbaldehydes with nitromethane, which led to the formation of (S)-enriched benzofuryl ß-nitro alcohols with satisfactory enantioselectivities (up to 98% ee). Using this catalytic protocol, bioactive (S)-benzofuryl ß-amino alcohols could be conveniently prepared in short steps.

Adsorption behaviors of novel betaines on the wettability of the quartz surface.

The contact angle measurements for the aqueous solutions of two pairs of zwitterions on quartz surfaces have been investigated by the sessile drop analysis. The different physicochemical parameters such as the critical micelle concentration (CMC), surface tension, contact angle, surface excess on air-liquid and solid-liquid interfaces and work of adhesion have been estimated. The obtained results show that the contact angle of surfactants such as alkyl carboxylbetaine (ACB) and ditolyl substituted alkyl carboxylbetaine (BCB) remains almost constant in a wide range of surfactant concentration and increases gradually above CMC, which are quite different from traditional surfactants reported in the literature. Surfactants with bigger polar groups have a more steric effect on the quartz surface and the contact angle remains relatively unchanged. Moreover, an increase in quartz-liquid interfacial tension (γSL) has been observed due to the adsorption of four zwitterionic surfactants. Especially for ACB and BCB, at the surfactant concentrations higher than 5 × 10(-5) mol L(-1), a moderate increase in the interfacial tension of the quartz-liquid is observed, which suggests that ACB and BCB can form a saturated adsorption film briefly on the quartz surface and then adsorb again. However, the addition of alkyl sulfobetaine (ASB) and ditolyl substituted alkyl sulfobetaine (BSB) after CMC cannot adsorb on the quartz surface again due to the steric effect of bigger polar groups.