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.

Crown ether-like octanuclear molybdenum(V) clusters for cation binding and gas adsorption.

Octanuclear polyoxomolybdenum-based porous materials, Na8[Mo8O8(µ2-O)8(µ2-OH)8(3-apz)4]2·26H2O (1, 3-Hapz = 3-aminopyrazole), K8[Mo8O8(µ2-O)8(µ2-OH)8(3-apz)4]2·7H2O (2) and (NH4)4[Mo8O8(µ2-O)8(µ2-OH)4(3-apz)8]·20.5H2O (3), have been successfully synthesized by a hydrothermal method and fully characterized. X-ray structural analyses show that microporous materials 1-3 contain round pores formed by octanuclear molybdenum-oxygen groups connected sequentially with pore sizes of 4.0, 4.0, and 4.8 Å, respectively. Both 1 and 2 are composed of two {Mo8} rings, which are connected by strong intramolecular hydrogen bonds between bridging hydroxy groups and oxygen atoms to form dimeric structures. The central pores in 1 and 2 are occupied by Na+ and K+, respectively, while they are empty in 3. This reflects the structural expansion and contraction effects induced by different cations. Through intermolecular stacking, 1-3 also exhibit channels with sizes of 14.0 × 6.4, 4.6 × 2.6, and 5.4 × 5.4 Å, respectively, which were used for the studies of gas adsorption. The results show that 1-3 can selectively adsorb CO2 and O2, including the empty hole in 3, while they show little or no affinity for gases H2, N2, and CH4. Moreover, an additional polyoxomolybdenum-based species (Mo8O26)n·4n(3-H2apz) (4) has been obtained with protonated 3-aminopyrazole in the absence of a reducing agent, which can serve as an intermediate for the polyoxomolybdenum-based porous products.

Analyses of the electronic structures of FeFe-cofactors compared with those of FeMo- and FeV-cofactors and their P-clusters.

The electronic structures of FeFe-cofactors (FeFe-cos) in resting and turnover states, together with their PN clusters from iron-only nitrogenases, have been calculated using the bond valence method, and their crystallographic data were reported recently and deposited in the Protein Data Bank (PDB codes: 8BOQ and 8OIE). The calculated results have also been compared with those of their homologous Mo- and V-nitrogenases. For FeFe-cos in the resting state, Fe1/2/4/5/6/7/8 atoms are prone to Fe3+, while the Fe3 atom shows different degrees of mixed valences. The results support that the Fe8 atom at the terminal positions of FeFe-cos possesses the same oxidation states as the Mo3+/V3+ atoms of FeMo-/FeV-cos. In the turnover state, the overall oxidation state of FeFe-co is slightly reduced than those in the resting species, and its electronic configuration is rearranged after the substitution of S2B with OH, compatible with those found in CO-bound FeV-co. Moreover, the calculations give the formal oxidation states of 6Fe2+-2Fe3+ for the electronic structures of PN clusters in Fe-nitrogenases. By the comparison of Mo-, V- and Fe-nitrogenases, the overall oxidation levels of 7Fe atoms (Fe1-Fe7) for both FeFe- and FeMo-cos in resting states are found to be higher than that of FeV-co. For the PN clusters in MoFe-, VFe- and FeFe-proteins, they all exhibit a strong reductive character.

Genome Mining of Cinnamoyl-Containing Nonribosomal Peptide Gene Clusters Directs the Production of Malacinnamycin.

Cinnamoyl-containing nonribosomal peptides (CCNPs) constitute a unique family of actinobacterial secondary metabolites that display a broad spectrum of biological activities. Here, we present a genome mining approach targeting cyclase and is isomerase to discover new CCNPs, which led to the identification of 207 putative CCNP gene clusters from public bacterial genome databases. After strain prioritization, a novel class of CCNP-type glycopeptides named malacinnamycin was identified. A plausible biosynthetic pathway for malacinnamycin was deduced by bioinformatics analysis.

Protonated and deprotonated vanadyl imidazole tartrates for the mimics of the vanadium coordination in the FeV-cofactor of V-nitrogenase.

Chiral imidazole-based oxidovanadium tartrates (H2im)2[Δ,Λ-VIV2O2(R,R-H2tart)(R,R-tart)(Him)2]·Him (1, H4tart = tartaric acid, Him = imidazole) and [Λ,Λ-VIV2O2(R,R-tart)(Him)6]·4H2O (2) and their corresponding enantiomers (H2im)2[Λ,Δ-VIV2O2(S,S-H2tart)(S,S-tart)(Him)2]·Him (3) and [Δ,Δ-VIV2O2(S,S-tart)(Him)6]·4H2O (4) were obtained in alkaline solutions. Interestingly, the tartrates chelate with vanadium bidentately through α-alkoxy/α-hydroxy and α-carboxy groups and imidazole coordinates monodentately through nitrogen atom. It is worth noting that complexes 1 and 3 contain both protonated α-hydroxy and deprotonated α-alkoxy groups simultaneously, which have short V-Oα-alkoxy distances [1.976(4)av Å in 1-4] and long V-Oα-hydroxy distances [2.237(3)av Å in 1 and 2.230(2)av Å in 3]. There is an interesting strong intramolecular hydrogen bond [O(11)⋯O(1) 2.731(5) Å] between the two parts in 1 and 3. The protonated V-O distances are closer to the average bond distance in reported FeV-cofactors (FeV-cos, V-Oα-alkoxy 2.156av Å) in VFe proteins, which corresponds to the feasible protonation of coordinated α-hydroxy in R-homocitrate in V-nitrogenase, showing the homocitrate in the mechanistic model for nitrogen reduction as a secondary proton donor. Furthermore, vibrational circular dichroism (VCD) and IR spectra of 1-4 pointed out the disparity between the characteristic vibrations of the C-O and C-OH groups clearly. EPR experiment and theoretical calculations support +4 oxidation states for vanadium in 1-4. Solution 13C {1H} NMR spectra and CV analyses exhibited the solution properties for 1 and 2, respectively, which indicates that there should be a rapid exchange equilibrium between the protonated and deprotonated species in solutions.

Asymmetric dinuclear, hexanuclear and octanuclear oxovanadium citrates with triazolates: novel mixed-ligands and mixed-valence complexes.

The triazolate-assisted asymmetric dinuclear oxovanadium(IV) citrate [V2O2(cit)(Hdatrz)3]·5H2O (1, H4cit = citric acid, Hdatrz = 1H-1,2,4-triazole-3,5-diamine) and its additive salt [V2O2(cit)(Hdatrz)3][V2O2(cit)2]½·2H2datrz·9.5H2O (2) and the polymerized hexanuclear product [V6O6(µ3-O)2(cit)2(Hdatrz)4]·4H2O (3) have been isolated at different temperatures, respectively. Adduct 2 shows strong evidence for the conversion of a symmetric dinuclear oxovanadium(IV) citrate to a mixed-ligand asymmetric oxovanadium(IV) citrate. Moreover, a fully oxidized trinuclear vanadium(V) species [V3O6(µ2-OH)(µ3-O)(Hdatrz)2]·4.5H2O (4) has also been isolated as a quasi-intermediate product of 3 without the coordination of citrate. Intriguingly, an octanuclear mixed-valence oxovanadium(V/IV) citrate K2{[VIV/V2O2(cit)(Hdatrz)(datrz)]2[VIV2O2(cit)(Hdatrz)(datrz)]2}·27.5H2O (5) has been obtained with different vanadium units, where dinuclear mixed-ligands and mixed-valence oxovanadium(IV/V) citrates [VIV/V2O2(cit)(Hdatrz)(datrz)] (5a) and [VIV2O2(cit)(Hdatrz)(datrz)] (5b) have been trapped. Citrate adopts a µ2-η1:η1:η1:η2 coordination mode in 1, 2 and 5, while a µ3-η1:η1:η1:η2 fashion has been observed in 3. Unlike 1-4, complex 5 contains both protonated and deprotonated triazolates simultaneously, where four triazolates further coordinate in a µ3-η1:η1:η1 manner to construct an octanuclear unit. These different structural features in 1-5 are dominated by flexible multidentate citrates and protonated/deprotonated triazolates, showing their synergistic effects. Furthermore, 1 exhibits a rectangular channel, showing preferential adsorption of O2 and CO2 over gases N2, H2, and CH4.

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.

Octa- and Tetradecanuclear Mixed-Valent Vanadium(III/IV) Malates with Triazoles: Gas Adsorptions, Chiral Interface Recognition, and In Situ Decarboxylation.

Spontaneous resolution has been found for a pair of cage-like octanuclear mixed-valent vanadium(III/IV) malate enantiomers [Δ-VIII4VIV4O5(R-mal)6(Hdatrz)6]·44.5H2O (ΔR-1) and [Λ-VIII4VIV4O5(S-mal)6(Hdatrz)6]·38.5H2O (ΛS-1, H3mal = malic acid; Hdatrz = 3,5-diamino-1,2,4-triazole). Their racemic reduced product K7[VIII5VIV3O5(R,S-mal)6(trz)6]·17H2O (2) and tetradecanuclear species K11[VIII3VIV11O11(R,S-mal)12(atrz)6]·45.5H2O (3) (Htrz = 1,2,3-triazole, Hatrz = 3-amino-1,2,4-triazole) have also been obtained. In situ decarboxylation happens for 3-amino-1,2,4-triazole-5-carboxylic acid (H2atrzc) to yield 3-amino-1,2,4-triazole under hydrothermal conditions. Both 1 and 2 show an interesting bicapped-triangular-prismatic {V8O5(mal)6} building block, which further decorates symmetrically with three [VIV2O2(R,S-mal)2]2- units to construct a pinwheel-like {V14}-cluster, 3. Bond valence calculation sum (BVS) analyses manifest that the oxidation states of bicapped V atoms are +3 in 1-3, while the other V atoms in the {V6O5} core are ambiguous between +3 and +4 states with strong electron delocalization. Intriguingly, the triple helical chains in 1 associate in parallel to generate an amine-functionalized chiral polyoxovanadate (POV)-based supramolecular open-framework. The diameter of the interior channel is 13.6 Å, showing preferential adsorption of CO2 over gases N2, H2, and CH4. Importantly, homochiral framework ΔR-1 is capable of performing chiral interface recognition for R-1,3-butanediol (R-BDO) through host-guest interactions, as confirmed by the structural analysis of the host-guest complex ΔR-1·3(R-BDO). There are six R-BDO molecules in the channel of ΔR-1.

Crown ether-like discrete clusters for sodium binding and gas adsorption.

Hexanuclear polyoxomolybdenum-based discrete supermolecules Nax[MoV6O6(µ2-O)9(Htrz)6-x(trz)x]·nH2O (x = 0, n = 15, 1; x = 1, n = 12, 2; x = 2, n = 10, 3; x = 2, n = 49, 4; Htrz = 1H-1,2,3-triazole) have been prepared and fully characterized with different amounts of sodium cations inside and outside the intrinsic holes. Structural analyses demonstrate that they all exist a triangular channel constructed by six molybdenum-oxygen groups with inner diameters of 2.86 (1), 2.48 (2), and 3.04 (3/4) Å, respectively. Zero, one, or two univalent enthetic guest Na+ have been hosted around the structural centers, which reflect the expansion and contraction effects at microscopic level. Water-soluble species can serve as crown ether-like metallacycles before and after the sodium binding. Diverse nanoscale pores are further formed through intermolecular accumulations with hydrogen bonding. Gas adsorption studies indicate that 2-4 can selectively adsorb CO2 and O2 but have little or even no affinities toward H2, N2, and CH4. Theoretical calculations corroborate the roles of Na+ and auxiliary ligand with different states in bond distances, molecular orbitals, electrostatic potentials, and lattice energies in these discrete clusters. The binding orders of sodium cations in 2-4 are similar with the classical crown ethers, where 2 is the strongest one with 2.226(4)av Å for sodium cation bonded to six O atoms.

Statistical analyses of the oxidized P-clusters in MoFe proteins using the bond-valence method: towards their electron transfer in nitrogenases.

26 well selected oxidized P-clusters (P2+) from the crystallographic data deposited in the Protein Data Bank have been analysed statistically by the bond-valence sum method with weighting schemes for MoFe proteins at different resolutions. Interestingly, the oxidation states of P2+ clusters correspond to Fe23+Fe62+ with high electron delocalization, showing the same oxidation states as the resting states of P-clusters (PN) in nitrogenases. The previously uncertain reduction of P2+ to PN clusters by two electrons was assigned as a double protonation of P2+, in which decoordination of the serine residue and the peptide chain of cysteine take place, in MoFe proteins. This is further supported by the obviously shorter α-alkoxy C-O bond (average of 1.398 Å) in P2+ clusters and longer α-hydroxy C-O bond (average of 1.422 Å) in PN clusters, while no change is observed in the electronic structures of Fe8S7 Fe atoms in P-clusters. Spatially, the calculations show that Fe3 and Fe6, the most oxidized and most reduced Fe atoms, have the shortest distances of 9.329 Šfrom the homocitrate in the FeMo cofactor and 14.947 Šfrom the [Fe4S4] cluster, respectively, and may well function as important electron-transport sites.

m5C-dependent cross-regulation between nuclear reader ALYREF and writer NSUN2 promotes urothelial bladder cancer malignancy through facilitating RABL6/TK1 mRNAs splicing and stabilization.

The significance of 5-methylcytosine (m5C) methylation in human malignancies has become an increasing focus of investigation. Here, we show that m5C regulators including writers, readers and erasers, are predominantly upregulated in urothelial carcinoma of the bladder (UCB) derived from Sun Yat-sen University Cancer Center and The Cancer Genome Atlas cohort. In addition, NOP2/Sun RNA methyltransferase family member 2 (NSUN2) as a methyltransferase and Aly/REF export factor (ALYREF) as a nuclear m5C reader, are frequently coexpressed in UCB. By applying patient-derived organoids model and orthotopic xenograft mice model, we demonstrate that ALYREF enhances proliferation and invasion of UCB cells in an m5C-dependent manner. Integration of tanscriptome-wide RNA bisulphite sequencing (BisSeq), RNA-sequencing (RNA-seq) and RNA Immunoprecipitation (RIP)-seq analysis revealed that ALYREF specifically binds to hypermethylated m5C site in RAB, member RAS oncogene family like 6 (RABL6) and thymidine kinase 1 (TK1) mRNA via its K171 domain. ALYREF controls UCB malignancies through promoting hypermethylated RABL6 and TK1 mRNA for splicing and stabilization. Moreover, ALYREF recognizes hypermethylated m5C site of NSUN2, resulting in NSUN2 upregulation in UCB. Clinically, the patients with high coexpression of ALYREF/RABL6/TK1 axis had the poorest overall survival. Our study unveils an m5C dependent cross-regulation between nuclear reader ALYREF and m5C writer NSUN2 in activation of hypermethylated m5C oncogenic RNA through promoting splicing and maintaining stabilization, consequently leading to tumor progression, which provides profound insights into therapeutic strategy for UCB.

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.

Binuclear, tetranuclear and hexadecanuclear thio-oxomolybdenum(V/IV) glycolates with selective adsorptions of gases.

By adjusting the pH values of the solutions, binuclear, tetranuclear and hexadecanuclear glycolato thio- and oxomolybdenum(V/IV) complexes [MoV2O2(µ2-O)(µ2-S)(Hglyc)2(Hpz)2]·H2O (1, H2glyc = glycolic acid, Hpz = pyrazole), (Hdpa)[MoV2O2(µ2-S)2(Hglyc)(glyc)(H2O)] (2, dpa = 2,2'-dipyridylamine), (Hdpa)4[MoV4O4(µ3-O)2(µ2-S)2(glyc)2(S2O3)2] (3) and Na2[MoIV4MoV12O12(µ2-O)6(µ2-OH)2(µ3-O)12(glyc)4(Hpz)4(pz)8]·28H2O (4) have been obtained successfully. Here the glycolates existed in varying aggregates with different degrees of protonation and deprotonation in 1-4. The stable formations of 1 and 2 are attributed to strong hydrogen bonds formed between the molecules. In particular, the asymmetric unit in 2 is a tetramer linked by hydrogen bonding [2.574(9) Å] between α-hydroxy and α-alkoxy groups for further construction of unsaturated penta-coordination environments. Moreover, deprotonated glycolates act as bridging ligands to form tetra- and hexadecanuclear compounds 3 and 4, respectively. The smallest unit in 4 exhibits mixed valences of 4+ and 5+ simultaneously, where its gas adsorption experiments manifest that 4 is obviously beneficial for O2 and CO2 compared with no adsorption of N2, CH4 and H2 at different pressures.

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.

Successive constructions of regular tetra-, hexa- and octanuclear microporous polyoxovanadates(III) for gas adsorption.

Pyrazole-assisted tetranuclear microporous polyoxovanadates(III) (POVs) (NH4)2K2[V4(µ2-OH)4(ox)4(pz)4]·9H2O (1, ox = oxalate and pz = pyrazole) and (NH4)2Na2[V4(µ2-OH)4(ox)4(4-mpz)4]·7H2O (2, 4-mpz = 4-methylpyrazole) have been constructed in reduced media, along with their triazole neutral hexa- and octanuclear products K2[V6(µ2-OH)6(ox)6(Hdatrz)6]Cl2·29.5H2O (3) and [V8(µ2-OH)8(SO3)8(Hdatrz)8]·38H2O (4, Hdatrz = 1H-1,2,4-triazole-3,5-diamine) successively. Both polyanionic structures of 1 and 2 share similar inorganic building blocks that consist of regular {V4(µ2-OH)4} skeletons with an inner diameter of 2.8 Å, while a paddle wheel-shaped cluster 3 contains a {V6(µ2-OH)6} skeleton with two chlorides encapsulated around the center of the ring, occupying a hole of 3.7 Å. An interesting isolated intrinsic polyoxometalate-based metal-organic framework (POMOF) 4 exists as an octanuclear petaloid-like skeleton {V8(µ2-OH)8(SO3)8} with an inner diameter of 5.2 Å. Bond valence sum calculations manifest that all V ions have severely reduced +3 oxidation states in 1-4, which are supported by charge balance, structural and magnetic data. Moreover, gas adsorptions indicate that 1, 2 and 4 can adsorb CO2 and O2 more favorably than N2, CH4 and H2 gases. Compared with 1 and 2, due to the functionalization of microchannels with Lewis base amino and hydroxy groups and uncoordinated azolate N-donors inside POMOF 4, it should have notable affinities toward CO2 adsorption.

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.

Statistical analysis of PN clusters in Mo/VFe protein crystals using a bond valence method toward their electronic structures.

Nowadays, large numbers of MoFe proteins have been reported and their crystal data obtained by X-ray crystallography and uploaded to the Protein Data Bank (PDB). By big data analysis using a bond valence method, we make conclusions based on 79 selected PN in all 119 P-clusters of 53 MoFe proteins and 10 P-clusters of 5 VFe proteins from all deposited crystallographic data of the PDB. In the condition of MoFe protein crystals, the resting state PN clusters are proposed to have the formal oxidation state of 2Fe(iii)6Fe(ii), hiding two oxidized electron holes with high electron delocalization. The calculations show that Fe1, Fe2, Fe5, Fe6 and Fe7 perform unequivocally as Fe2+, and Fe3 is remarkably prone to Fe(iii), while Fe4 and Fe8 have different degrees of mixed valences. For PN clusters in VFe protein crystals, Fe1, Fe2, Fe4, Fe5 and Fe6 tend to be Fe2+, but the electron distributions rearrange with Fe7 and Fe8 being more oxidized mixed valences, and Fe3 presenting a little more reductive mixed valence than that in MoFe proteins. In terms of spatial location, Fe3 and Fe6 in P-clusters of MoFe proteins are calculated as the most oxidized and reduced irons, which have the shortest distances from homocitrate in the FeMo-cofactor and [Fe4S4] cluster, respectively, and thus could function as potential electron transport sites. This work shows different electron distributions of PN clusters in Mo/VFe protein crystals, from those obtained from previous data from solution with excess reducing agent from which it was concluded that PN clusters are all ferrous according to Mössbauer and electron paramagnetic resonance spectra.