Chemical constituents from the stems of Acanthopanax senticosus with their cytotoxic activities.

A new coumestan named 7,5'-dihydroxy-4'-(3''-hydroxy-3''-methyl-trans-isobut-1''-enyl) coumestan (1), together with five known compounds (2-6), was isolated from the EtOAc-soluble extract of the stems of Acanthopanax senticosus. Their structures were elucidated based on extensive spectroscopic analyses. All the isolates were evaluated for in vitro cytotoxic activities against four human cancer cells including HepG2, A549, HeLa and MCF-7. Among them, the new compound 1 was found to exhibit significant cytotoxic activity on HeLa cells with IC50 value of 6.5 µM.

Screening for early rheumatoid arthritis using high-frequency ultrasound, serum RANKL, and OPG detection.

OBJECTIVE: To conduct a comparative study of high-frequency ultrasound and magnetic resonance imaging (MRI) combined with serum RANKL and OPG detection, and assess the efficacy of high-frequency ultrasound with RANKL and OPG detection in screening early rheumatoid arthritis (RA). METHOD: High-frequency ultrasound and MRI were performed on both carpal joints of 60 patients with early RA, and the frequencies of synovitis, joint effusion, tenosynovitis, and bone erosion detected by high-frequency ultrasound and MRI were observed. The serum levels of receptor activator for nuclear factor-κB ligand (RANKL) and osteoclastogenesis inhibitory factor (OPG) were also detected. The serum levels of RANKL and OPG were also detected in 80 normal healthy examinees. The data were recorded and statistically analyzed. RESULTS: The detection rates of carpal synovitis, joint effusion, tenosynovitis, and bone erosion in RA patients by high-frequency ultrasound were 81.66%, 69.16%, 63.33%, and 1.66%, respectively, while the detection rates by MRI were 80.00%, 71.66%, 65.00%, and 15.00%, respectively. There was no significant difference between high-frequency ultrasound and MRI in the detection rates of carpal synovitis, joint effusion, and tenosynovitis in RA patients (P > 0.05), while the detection rate of bone erosion by high-frequency ultrasound was significantly lower than that by MRI. The serum levels of RANKL and OPG in RA patients were 231.47 and 68.71, respectively, while the serum levels of RANKL and OPG in normal healthy examinees were 123.51 and 385.05, respectively. The serum RANKL levels of RA patients were significantly higher than those of healthy examinees, while the serum OPG levels of RA patients were significantly lower than those of healthy examinees, which were statistically significant (P < 0.01). The AUC values of the ROC curves obtained by high-frequency ultrasound and MRI combined with serum RANKL and OPG detection in Synovitis modeling were 0.955 and 0.954, respectively. The AUC values of the ROC curves obtained from the joint fusion modeling using high-frequency ultrasound and MRI combined with serum RANKL and OPG detection were 0.949 and 0.950, respectively. The AUC values of the ROC curves obtained from modeling Tenosynovitis using high-frequency ultrasound and MRI combined with serum RANKL and OPG detection were 0.941 and 0.949, respectively. The AUC values of ROC curves obtained by combining high-frequency ultrasound and MRI with serum RANKL and OPG detection in Bone erosion modeling were 0.908 and 0.923, respectively. CONCLUSION: High-frequency ultrasound combined with serum RANKL and OPG detection has comparable effects to MRI on screening early RA, providing a safe, simple, and cost-effective screening method for the early detection of RA patients. Key Points • High-frequency ultrasound and MRI can effectively detect early lesions of the wrist joints in RA patients. • Ultrasound diagnosis has the advantages of being quick, inexpensive, and repeatable, making it the preferred choice of imaging examination for RA patients at an early stage.

Bond energy of IrO+: guided ion-beam and theoretical studies of the reaction of Ir+ (5F) with O2.

The kinetic-energy dependence of the Ir(+) + O2 reaction is examined using guided ion-beam mass spectrometry. The cross section for IrO(+) formation from ground state Ir(+)((5)F) is unusual, and several means are used to interpret the kinetic energy dependence for IrO(+) formation. In analogy with recent observations for the analogous Re(+) and Os(+) systems, we believe the cross section is most accurately analyzed assuming there are two features. This analysis yields a threshold leading to D0(Ir(+)-O) = 4.26 ± 0.09 eV, with the higher energy feature having a threshold 0.72 ± 0.25 eV higher in energy. This bond energy, which is consistent with much less precise values determined in the literature, can be combined with literature information to suggest that D0(IrO) = 4.25 ± 0.44 eV and IE(IrO) = 8.96 ± 0.45 eV. The nature of the bonding for IrO(+) and IrO2(+) is discussed and analyzed primarily using theoretical calculations at the B3LYP/def2-TZVPPD level of theory. Bond energies for ground state IrO(+), identified as (5)Δ, are calculated at this level as well as BP86 and CCSD(T,full) levels using several different basis sets. BP86 theoretical bond energies are higher than the experimental value, whereas B3LYP and CCSD(T,full) values are slightly lower, especially after estimated spin-orbit corrections. Potential energy surfaces for the reaction of Ir(+) with O2 are also calculated at the B3LYP/def2-TZVPPD level of theory and reveal that ground state Ir(+)((5)F) inserts into O2 by forming several different Ir(+)(O2) complexes. These can then couple along additional surfaces to form low-lying states of the dioxide IrO2(+). The very interesting parallel behavior of the Re, Os, and Ir heavy metal systems is explored in terms of adiabatic and nonadiabatic behavior, although no unambiguous explanation is evident.

[Genome-wide analysis of cytochrome P450 monooxygenase genes in the tobacco].

Plant cytochrome P450 monooxygenases (CYP) constitute a large superfamily of heme-thiolate proteins, which are involved in a wide range of metabolic pathways. In this study, comparative genomic approaches were used to analyze tobacco CYP genes and their expression patterns. Based on analysis of the tobacco genomic DNA sequences that are currently available, 263 P450 genes that belong to 44 distinct clans were identified. EST evidence from 173 of the CYPs suggested that these genes are transcribed. Sequence features and secondary structures of the tobacco P450 genes were further analyzed through comparison with known P450 proteins. The expression profiles of 73 P450 genes were subsequently investigated by analyses of tobacco microarray data and RT-PCR. The results showed a variety of expression patterns of these genes in different tissues with a number of genes expressed in a tissue-specific manner. This study has set a foundation for further studies on functions of P450 genes in tobacco.

Antagonistic effects of Bacillus cereus strain B-02 on morphology, ultrastructure and cytophysiology of Botrytis cinerea.

The study on antagonistic mechanism of biocontrol strains gives the premise and basis for efficient and stable biological control. This study aimes to overcome of biocontrol agent in aspects of complicated and diversified mode of action, short-lasting and unstable efficacy in the production processes. This study elucidated the antagonistic mechanism of Bacillus cereus strain B-02 on Botrytis cinerea by detecting changes in morphology, ultrastructure and physiology in affected hyphae of Botrytis cinerea. Which provided certain theoretical and practical significance for biological control of gray mould caused by B. cinerea. B. cereus strain B-02 isolated from tomato rhizosphere mightily suppressed gray mold in tomato caused by B. cinerea. Spore germination and hyphal growth of B. cinerea were inhibited by B. cereus strain B-02. Changes of cell morphology such as distortion, shrinking and swelling were observed by SEM. TEM observation further indicated the ultrastructural alterations of hyphae, including mitochondrion reduction, un-membranous inclusion in cytoplasm, considerable thickening of cell walls, and electronic density enhancement. LSCM observation revealed the fluorescence intensity of nucleus DNA, mitochondrion DNA and reactive oxygen radical in treated hyphae were all stronger than control and the difference was significant (P < 0.01). These results indicated that the antagonistic effects of B. cereus strain B-02 on B. cinerea were likely due to a combination of abnormal synthesis of nucleus DNA and mitochondrion DNA and multifarious ultrastructural alterations in hyphal cell.

[Nondestructive measurement of sugar content of Hami melon based on diffuse reflectance hyperspectral imaging technique].

The research on nondestructive test for detecting the sugar content of Hami melon by the technology of hyperspectral imaging was put forward. The research used the hyperspectral imaging system to get the diffuse reflective spectrum information (400 - 1 000 nm) of anilox class Hami melon sugar content, chose effective whole wavelength (500 - 820 nm)to do the modeling regression analysis the sugar content of Hami melon. The research compared the correction method of MSC and SNV, and also compared the influence of accuracy of modeling in terms of the spectrum pretreatment methods of original spectrum, first order differential, second order differential; Using the methods of PLS, SMLR and PCR, the comparative analysis of sugar content detection model effect with skin Hami melon and peel Hami melon was conducted. The results showed that after the original spectrum being processed by MSC and first order differential spectrum, modeling effect could be very good using the method of PLS and SMLR. Synthesizing correction set correlation coefficient and forecast modeling effect, it's feasible to detect the sugar content of skin Hami melon by the PLS method, with a correction sample correlation coefficient (R(c)) of 0.861 and the lower root mean square errors of correction (RMSEC) of 0.627, and a prediction sample correlation coefficient (R(p)) of 0.706 and root mean square errors of prediction (RMSEP) of 0.873. The best effect to detecti the sugar content of peel Hami melon was obtained by the SMLR method with a correction sample correlation coefficient (R(c)) of 0.928 and the lower root mean square errors of correction (RMSEC) of 0.458, with a Prediction sample correlation coefficient (R(p)) of 0.818 and root mean square errors of prediction (RMSEP) of 0.727. The results of this study indicate that the technology of hyperspectral imaging can be used to predict the sugar content of Hami melon.

The Clinical and Pathological Features of Children With Microscopic Polyangiitis.

Objective: The aim of this study was to explore the clinical features, pathological characteristics, and the prognosis of children with microscopic polyangiitis (MPA). Methods: Ten children with MPA that were hospitalized in our hospital were included in this study. The children's pre-diagnosis status, clinical manifestations, renal pathology, treatment, and prognosis data were analyzed retrospectively. Results: All 10 cases included female patients with a median age of 8.9 years old at the time of diagnosis. MPO-ANCA antibody was positive in all cases, combined with a positive anti-GBM antibody in two cases. Nine cases had primary AAV and one had antithyroid drug (ATD)-associated MPA (secondary to methimazole). Renal involvement was found in all 10 patients, lung impairment was present in eight cases, and anemia was present in nine patients. Renal biopsies were performed in all 10 patients. Segmental focal or global glomerular necrosis was observed in 70% of the patients (7/10). The treatment mainly included steroid use combined with Cyclophosphamide and Mycophenolate. The follow-up s of the patients revealed normal renal function in eight patients and progression to end-stage renal disease (ESRD) in two patients. Conclusions: Female predisposition and positive MPO-ANCA antibody were prominent in children with MPA. The patients' kidneys and lungs were the most frequently involved organs. Corticosteroid combined with immunosuppressive therapy was recommended for the treatment of MPA. Early diagnosis, prompt aggressive treatment, and regular follow-ups are also very important factors associated with a good prognosis.

Semisynthesis of CRV431.

The non-immune-suppressive cyclophilin inhibitor CRV431 is a clinical candidate to cure nonalcoholic steatohepatitis (NASH) and has the potential to treat liver fibrosis and cancer incidence. Herein we report a concise chemical semisynthesis of CRV431 in four steps from the commercially available cyclosporine, featuring in this the flow-chemistry-based methylenation an intermolecular ring-closing metathesis and a Rh-catalyzed diastereoselective hydrogenation.

The status and model of children primary nephrotic syndrome in continuing nursing.

BACKGROUND: Nephrotic syndrome (NS) is a common glomerular disease in children. Nursing during hospitalization alone cannot solve the psychological, physiological and social health problems of children. Continuing care models may provide patients with more continuous and efficient care services. Therefore, the present study aimed to provide theoretical support for the implementation and development of children's primary nephrotic syndrome (PNS) and children's chronic disease continuing nursing through the construction of a children's PNS continuing nursing model. METHODS: Each item of the transitional care model for children with PNS was demonstrated using the Delphi method for two rounds of correspondence. The main items included four components: the composition of personnel, the responsibilities of each member, the content of work, and the evaluation indicators. RESULTS: A transitional care model for children with PNS was formed. The expert judgment coefficient of two rounds of correspondence was 0.84, the familiarity degree coefficient was 0.76, the authority degree coefficient was 0.80, the coefficient of variation was between 0.02 and 0.23, and the coordination coefficient was 0.458 and 0.327, respectively (P<0.01). CONCLUSIONS: The experts in the present research were highly motivated, had a high degree of authority, and presented consistent opinions. Hence, the construction of a transitional care model for children with PNS is scientifically feasible.

Rapid and Visual Detection of Vibrio parahaemolyticus in Aquatic Foods Using blaCARB-17 Gene-Based Loop-Mediated Isothermal Amplification with Lateral Flow Dipstick (LAMP-LFD).

Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The blaCARB-17 gene is an intrinsic ß-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this blaCARB-17 gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg2+, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63°C for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10-4 ng/µl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.

Targeting Extracellular Cyclophilin A via an Albumin-Binding Cyclosporine A Analogue.

An albumin-binding CsA analogue 4MCsA was achieved by attachment of a thiol-reactive maleimide group at the side-chain of P4 position of CsA derivative. 4MCsA was semi-synthesized from CsA, and the cell-impermeability of albumin-4MCsA was detected by mass spectrometry and a competitive flow cytometry. 4MCsA exhibits inhibition of chemotaxis activity and inflammation by targeting extracellular CypA without immunosuppressive effect and cellular toxicity. These combined results suggested that 4MCsA can be restricted extracellularly through covalently binding to Cys34 of albumin with its maleimide group, and regulate the functions of cyclophilin A extracellularly.

Oxidation of atomic gold ions: thermochemistry for the activation of O(2) and N(2)O BY Au(+) ((1)S(0) and (3)D).

Reaction of Au(+) ((1)S(0) and (3)D) with O(2) and N(2)O is studied as a function of kinetic energy using guided ion beam tandem mass spectrometry. A flow tube ion source produces Au(+) primarily in its (1)S(0) (5d(10)) electronic ground state level but with some (3)D and perhaps higher lying excited states. The distribution of states can be altered by adding N(2)O, which completely quenches the excited states, or CH(4) to the flow gases. Cross sections as a function of kinetic energy are measured for both neutral reagents and both ground and excited states of Au(+). Formation of AuO(+) is common to both systems with the N(2)O system also exhibiting AuN(2)(+) and AuNO(+) formation. All reactions of Au(+) ((1)S(0)) are observed to be endothermic, whereas the excitation energy available to the (3)D state allows some reactions to be exothermic. Because of the closed shell character of ground state Au(+) ((1)S(0), 5d(10)), the reactivity of these systems is low and has cross sections with onsets and peaks at higher energies than expected from the known thermochemistry but lower than energies expected from impulsive processes. Analyses of the endothermic reaction cross sections yield the 0 K bond dissociation energy (BDE) in eV of D(0)(Au(+)-O) = 1.12 ± 0.08, D(0)(Au(+)-N(2)) ≥ 0.30 ± 0.04, and D(0)(Au(+)-NO) = 0.89 ± 0.17, values that are all speculative because of the unusual experimental behavior. Combining the AuO(+) BDE measured here with literature data also yields the ionization energy of AuO as 10.38 ± 0.23 eV. Quantum chemical calculations show reasonable agreement with the experimental bond energies and provide the electronic structures of these species.

[CCN3 regulates the proliferation and apoptosis in periodontal ligament fibroblasts].

PURPOSE: To investigate the effect of CCN3 on proliferation and apoptosis in periodontal ligament fibroblasts (PDLFs) and related mechanism. METHODS: Recombinant vector pcDNA.3.1-CCN3 was constructed and transfected into human PDLFs to overexpress CCN3. CCN3 siRNA was transfected to inhibit CCN3. Fra-1 siRNA was transfected into the PDLFs with CCN3 inhibition to realize the inhibition of CCN3 and Fra-1 in the meantime. mRNA expressions of CCN3 and Fra-1 were measured by quantitative real-time PCR (qRT-PCR). The protein expressions of CCN3, Fra-1and Bcl-2 were detected by Western blot. Cell growth and viability and proliferation of PDLFs were measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and bromodeoxyuridine (BrdU) assays; Caspase-3 activity was tested by using the available kit. The data were analyzed with SPSS20.0 software package. RESULTS: The results showed that the mRNA (P<0.05) and protein (P<0.05) expressions of CCN3 were significantly up-regulated in the experimental group of pcDNA.3.1-CCN3 transfection. In addition, the mRNA (P<0.05) and protein (P<0.05) expressions of CCN3 were significantly decreased in the experimental group of CCN3 siRNA transfection. Cell growth (P<0.05) and viability, proliferation (P<0.05) and Bcl-2 (P<0.05) protein expression were increased, while caspase-3 activity (P<0.05) decreased in the PDLFs with CCN3 inhibition. However, CCN3 overexpression exhibited reversed effect. CCN3 overexpression or inhibition could remarkably constrain (P<0.05) or promote (P<0.01) the expression of Fra-1, respectively. Moreover, co-inhibition of CCN3 and Fra-1 could promote apoptosis (P<0.01) and inhibit proliferation (P<0.05) in PDLFs. CONCLUSIONS: The results suggest that inhibition of CCN3 could accelerate proliferation and constrain apoptosis via up-regulating expression of Fra-1 in PDLFs.

Overexpression of the Saussurea medusa chalcone isomerase gene in S. involucrata hairy root cultures enhances their biosynthesis of apigenin.

Saussurea involucrata is a medicinal plant well known for its flavonoids, including apigenin, which has been shown to significantly inhibit tumorigenesis. Since naturally occurring apigenin is in very low abundance, we took a transgenic approach to increase apigenin production by engineering the flavonoid pathway. A construct was made to contain the complete cDNA sequence of the Saussurea medusa chalcone isomerase (CHI) gene under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Using an Agrobacterium rhizogenes-mediated transformation system, the chi overexpression cassette was incorporated into the genome of S. involucrata, and transgenic hairy root lines were established. CHI converts naringenin chalcone into naringenin that is the precursor of apigenin. We observed that transgenic hairy root lines grew faster and produced higher levels of apigenin and total flavonoids than wild-type hairy roots did. Over a culture period of 5 weeks, the best-performing line (C46) accumulated 32.1 mgL(-1) apigenin and 647.8 mgL(-1) total flavonoids, or 12 and 4 times, respectively, higher than wild-type hairy roots did. The enhanced productivity corresponded to elevated CHI activity, confirming the key role that CHI played for total flavonoids and apigenin synthesis and the efficiency of the current metabolic engineering strategy.

Guided ion beam and theoretical study of the reactions of Ir+ with H2, D2, and HD.

We present the kinetic energy dependence of reactions of the late third-row transition metal cation Ir(+) with H(2), D(2), and HD measured using a guided ion beam tandem mass spectrometer. A flow tube ion source produces Ir(+) ions in its electronic ground state term and primarily in the ground spin-orbit level. Corresponding state-specific reaction cross sections are obtained. The kinetic energy dependence of the cross sections for forming IrH(+) and IrD(+) are analyzed to give a 0 K bond dissociation energy of D(0)(Ir(+)-H) = 3.12 +/- 0.06 eV. Ab initio calculations at the B3LYP/HW+/6-311+G(3p), BHLYP/HW+/6-311+G(3p), and QCISD(T)/HW+/6-311+G(3p) levels performed here show reasonable agreement with the experimental bond energies and with the previous theoretical values available. Theory also provides the electronic structures of these species and the reactive potential energy surfaces. We also compare this third-row transition metal system with those of the first-row and second-row congeners Co(+) and Rh(+). We find that Ir(+) has a stronger M(+)-H bond, which can be explained by the lanthanide contraction and relativistic effects that alter the relative size of the valence s and d orbitals. Results from reactions with HD provide insight into the reaction mechanisms and indicate that Ir(+) reacts largely via an insertion mechanism, in contrast with the lighter group 9 metal ions Co(+) and Rh(+) which react via direct mechanisms.

Down-regulation of aquaporin3 expression by lipopolysaccharide via p38/c-Jun N-terminal kinase signalling pathway in HT-29 human colon epithelial cells.

AIM: To investigate the influence of lipopolysaccharide (LPS) through the p38/c-Jun N-terminal kinase (JNK) signalling pathway on aquaporin 3 (AQP3) expression in HT-29 human colon epithelial cells. METHODS: HT-29 cells were treated with LPS, and then the membrane localisation of AQP3 was examined by immunofluorescence staining. The mRNA and protein expression of AQP3 with LPS exposure was measured by real-time reverse transcription-PCR and Western blot, respectively. Activation of p38 and JNK was evaluated by detection of phosphorylation of p38 and JNK using Western blot assay. AQP3 protein expression was determined by Western blot in cells after treatment with SB203580, a selective p38 MAPK inhibitor, or SP600125, a selective JNK inhibitor. RESULTS: In HT-29 cells, the transcription and protein expression of AQP3 were decreased by LPS in a dose- and time-dependent manner, the expression of AQP3 was significantly decreased with the increased concentration of LPS, and at a dose of 100 µg/mL LPS, AQP3 mRNA and protein levels were decreased by a maximum (P < 0.05) of 1.51-fold and 1.49-fold, respectively. When cells were treated with 100 µg/mL LPS for 0, 3, 6, 12, and 24 h, the AQP3 mRNA level was significantly decreased at an early time point of 3 h, and reached about 10% of the control level at 24 h post-treatment (P < 0.05). Down-regulation of AQP3 expression was significantly inhibited by the p38 inhibitor (SB203580) and JNK inhibitor (SP600125). CONCLUSION: p38 and JNK may be promising targets for the preservation of AQP3 expression and may be beneficial to the clinical management of diarrhoea.

Survival analysis of late-onset systemic lupus erythematosus: a cohort study in China.

The aim of this study is to explore the survival rate and risk factors of mortality in patients with late-onset systemic lupus erythematosus (SLE) in a large cohort. Clinical presentations, disease activity, organ damage scores, autoantibody profile, and mortality data were obtained retrospectively from late-onset SLE patients (onset age ≥50 years) diagnosed between 1995 and 2009. The risk factors of organ damage were evaluated by the chi-square test and logistic regression. The cumulative rate of survival was calculated by Kaplan-Meier method, and factors predictive of mortality were studied by Cox proportion hazard regression model. A total of 158 patients (132 female and 26 male) were studied. The average onset age was 58.66 ± 6.38 years and mean disease duration was 63.85 ± 48.17 months. One hundred and four patients had organ damage at the time of data analysis. Hematological system and kidney involvement were most common. Central nervous system involvement was relatively rare. In univariate logistic analysis, associations were found between SLE disease activity index (SLEDAI) at diagnosis (OR = 1.133, P = 0.001); renal involvement (OR = 2.441, P = 0.009) and edema (OR = 2.812, P = 0.003) were associated with organ damage. And SLEDAI at diagnosis (OR = 1.103, P = 0.034) was independent factor for organ damage in multivariate logistic regression. During the follow-up, 64 patients (51 female and 13 male) died. Five-, 10-, and 15-year survival rates were 80.4, 56.5, and 31.7 %, respectively. Median survival time was 123 months. The analysis of Cox proportion hazard regression model showed that age at disease onset (OR = 1.069, P = 0.002), compliance of medical care (OR = 3.282, P = 0.001), and SLEDAI at diagnosis (OR = 1.091, P = 0.003) were independent risk factors of mortality. Late-onset SLE has a poor long-term prognosis. Infection is the major cause of death in patients with late-onset lupus. Disease activity, medical care, and onset age are strongly related to death of late-onset SLE.

Activation of methane by gold cations: guided ion beam and theoretical studies.

The potential energy surface for activation of methane by the third-row transition metal cation, Au+, is studied experimentally by examining the kinetic energy dependence of this reaction using guided ion beam tandem mass spectrometry. A flow tube ion source produces Au+ primarily in its 1S0 (5d10) electronic ground state level but with some 3D (and perhaps higher lying) excited states that can be completely removed by a suitable quenching gas (N2O). Au+ (1S0) reacts with methane by endothermic dehydrogenation to form AuCH2+ as well as C-H bond cleavage to yield AuH+ and AuCH3+. The kinetic energy dependences of the cross sections for these endothermic reactions are analyzed to give 0 K bond dissociation energies (in eV) of D0(Au+ - CH2) = 3.70 +/- 0.07 and D0(Au+ -CH3) = 2.17 +/- 0.24. Ab initio calculations at the B3LYPHW + /6-311++G(3df,3p) level performed here show good agreement with the experimental bond energies and previous theoretical values available. Theory also provides the electronic structures of the product species as well as intermediates and transition states along the reactive potential energy surface. Surprisingly, the dehydrogenation reaction does not appear to involve an oxidative addition mechanism. We also compare this third-row transition metal system with the first-row and second-row congeners, Cu+ and Ag+. Differences in thermochemistry can be explained by the lanthanide contraction and relativistic effects that alter the relative size of the valence s and d orbitals.

Guided ion-beam studies of the reactions of Co(n)+ (n=2-20) with O2: cobalt cluster-oxide and -dioxide bond energies.

The kinetic-energy dependence for the reactions of Co(n)+ (n=2-20) with O2 is measured as a function of kinetic energy over a range of 0 to 10 eV in a guided ion-beam tandem mass spectrometer. A variety of Co(m)+, Co(m)O+, and Co(m)O2+ (m < or = n) product ions is observed, with the dioxide cluster ions dominating the products for all larger clusters. Reaction efficiencies of Co(n)+ cations with O2 are near unity for all but the dimer. Bond dissociation energies for both cobalt cluster oxides and dioxides are derived from threshold analysis of the energy dependence of the endothermic reactions using several different methods. These values show little dependence on cluster size for clusters larger than three atoms. The trends in this thermochemistry and the stabilities of oxygenated cobalt clusters are discussed. The bond energies of Co(n)+-O for larger clusters are found to be very close to the value for desorption of atomic oxygen from bulk-phase cobalt. Rate constants for O2 chemisorption on the cationic clusters are compared with results from previous work on cationic, anionic, and neutral cobalt clusters.

Probes of spin conservation in heavy metal reactions: experimental and theoretical studies of the reactions of Re+ with H2, D2, and HD.

A guided ion beam tandem mass spectrometer is used to examine the kinetic energy dependence of reactions of the third-row transition metal cation, Re(+), with molecular hydrogen and its isotopologues. A flow tube ion source produces Re(+) in its (7)S(3) electronic ground state. Reaction with H(2), D(2), and HD forms Re H(+)(Re D(+)) in endothermic processes. Modeling of the endothermic reaction cross sections yields the 0 K bond dissociation energy of D(0)(Re(+)-H)=2.29+/-0.07 eV (221+/-6 kJ/mol). The experimental thermochemistry is consistent with ab initio calculations, performed here and in the literature. Theory also provides the electronic structures of these species and is used to examine the reactive potential energy surfaces. Results from reactions with HD provide insight into the reaction mechanisms and indicate that the late metal ion, Re(+), reacts largely via a statistical mechanism. This is consistent with the potential energy surfaces which locate a stable Re H(2) (+)((5)B(2)) complex. Results for this third-row transition metal system are compared with the first-row congener (Mn(+)) and found to have much higher reactivity towards dihydrogen and stronger M(+)-H bonds. These differences can be attributed to efficient coupling among surfaces of different spin along with lanthanide contraction and relativistic effects.