以Ni/ZSM-5为催化剂制备纳米碳质材料(英文)

以ZSM-5分子筛为模板担载金属镍(Ni/ZSM-5)为催化剂,在不同质量分数Ni和温度下进行气相化学沉积过程得到氢气和纳米碳质材料(碳纳米管、纳米炭纤维)。氢气和纳米碳质材料的产率随Ni质量分数增加和反应温度升高而显著地增加,但当Ni含量为8%时产率却减小。纳米碳质材料的形貌与反应温度密切相关。在较高温度下可沉积出碳纳米管,在较低温度下则可得到纳米炭纤维。随着反应时间的延长Ni/ZSM-5的催化活性降低。     

The Assessment of Activity of Antiseptic Agents against Biofilm of Staphylococcus aureus Measured with the Use of Processed Microscopic Images

Staphylococcal biofilms are major causative factors of non-healing wound infections. Their treatment algorithms recommend the use of locally applied antiseptic agents to counteract the spread of infection. The efficacy of antiseptics against biofilm is assessed in vitro by a set of standard quantitative and semi-quantitative methods. The development of software for image processing additionally allowed for the obtainment of quantitative data from microscopic images of biofilm dyed with propidium iodine and SYTO-9 reagents, differentiating dead cells from live ones. In this work, the method of assessment of the impact of antiseptic agents on staphylococcal biofilm in vitro, based on biofilms’ processed images, was proposed and scrutinized with regard to clinically relevant antiseptics, polyhexanide, povidone–iodine and hypochlorite. The standard quantitative culturing method was applied to validate the obtained data from processed images. The results indicated significantly higher activity of polyhexanide and povidone–iodine than hypochlorite against staphylococcal biofilm. Taking into account the fact that in vitro results of the efficacy of antiseptic agents against staphylococcal biofilm are frequently applied to back up their use in hospitals and ambulatory units, our work should be considered an important tool; providing reliable, quantitative data in this regard.     

The Detectability of the Viral RNA in Blood and Cerebrospinal Fluid of Patients with Tick-Borne Encephalitis

Background: The detection rate of viral RNA in tick-borne encephalitis (TBE) is low and variable between studies, and its diagnostic/prognostic potential is not well defined. We attempted to detect RNA of TBE virus (TBEV) in body fluids of TBE patients. Methods: We studied 98 adults and 12 children with TBEV infection, stratified by the disease phase and presentation. EDTA blood and cerebrospinal fluid (CSF) samples were obtained upon hospital admission. RNA was extracted from freshly obtained plasma, concentrated leukocyte-enriched CSF, and whole blood samples, and real time PCR was performed with a Rotor-Gene Q thermocycler. Results: TBEV RNA was detected in (1) plasma of one (of the two studied) adult patients with an abortive infection, (2) plasma of two (of the two studied) adults in the peripheral phase of TBE, and (3) plasma and blood of an adult in the neurologic phase of TBE presenting as meningoencephalomyelitis. No CSF samples were TBEV RNA-positive. Conclusions: The detection of TBEV RNA in blood might be diagnostic in the peripheral phase of TBE. The lack of TBEV RNA in the CSF cellular fraction speaks against TBEV influx into the central nervous system with infiltrating leukocytes and is consistent with a relatively low intrathecal viral burden.     

Spectroscopic Characterization and Biological Activity of Hesperetin Schiff Bases and Their Cu(II) Complexes

The three Schiff base ligands, derivatives of hesperetin, HHSB (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]isonicotinohydrazide), HIN (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]benzhydrazide) and HTSC (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]thiosemicarbazide) and their copper complexes, CuHHSB, CuHIN, and CuHTSC were designed, synthesized and analyzed in terms of their spectral characterization and the genotoxic activity. Their structures were established using several methods: elemental analysis, FT-IR, UV-Vis, EPR, and ESI-MS. Spectral data showed that in the acetate complexes the tested Schiff bases act as neutral tridentate ligand coordinating to the copper ion through two oxygen (or oxygen and sulphur) donor atoms and a nitrogen donor atom. EPR measurements indicate that in solution the complexes keep their structures with the ligands remaining bound to copper(II) in a tridentate fashion with (O^–, N, O_ket) or (O^–, N, S) donor set. The genotoxic activity of the compounds was tested against model tumour (HeLa and Caco-2) and normal (LLC-PK1) cell lines. In HeLa cells the genotoxicity for all tested compounds was noticed, for HHSB and CuHHSB was the highest, for HTSC and CuHTSC–the lowest. Generally, Cu complexes displayed lower genotoxicity to HeLa cells than ligands. In the case of Caco-2 cell line HHSB and HTSC induced the strongest breaks to DNA. On the other side, CuHHSB and CuHTSC induced the highest DNA damage against LLC-PK1.     

Boron Clusters as Enhancers of RNase H Activity in the Smart Strategy of Gene Silencing by Antisense Oligonucleotides

Boron cluster-conjugated antisense oligonucleotides (B-ASOs) have already been developed as therapeutic agents with “two faces”, namely as potential antisense inhibitors of gene expression and as boron carriers for boron neutron capture therapy (BNCT). The previously observed high antisense activity of some B-ASOs targeting the epidermal growth factor receptor (EGFR) could not be rationally assigned to the positioning of the boron cluster unit: 1,2-dicarba-closo-dodecaborane (0), [(3,3′-Iron-1,2,1′,2′-dicarbollide) (1-), FESAN], and dodecaborate (2-) in the ASO chain and its structure or charge. For further understanding of this observation, we performed systematic studies on the efficiency of RNase H against a series of B-ASOs models. The results of kinetic analysis showed that pyrimidine-enriched B-ASO oligomers activated RNase H more efficiently than non-modified ASO. The presence of a single FESAN unit at a specific position of the B-ASO increased the kinetics of enzymatic hydrolysis of complementary RNA more than 30-fold compared with unmodified duplex ASO/RNA. Moreover, the rate of RNA hydrolysis enhanced with the increase in the negative charge of the boron cluster in the B-ASO chain. In conclusion, a “smart” strategy using ASOs conjugated with boron clusters is a milestone for the development of more efficient antisense therapeutic nucleic acids as inhibitors of gene expression.     

High effectiveness and safety of one-week antibiotic regimen in Helicobacter pylori eradication

Forty-three sporadic gastric cancers were analyzed with regard to whether mutations of simple repeated sequences in the transforming growth factor beta type II receptor (TbetaR-II) gene are associated with microsatellite instability (MSI) and gastric carcinogenesis. In 12 of the 43 cancers (28%), MSI was observed at least at 1 of the 2 microsatellite loci. Frameshift mutations of the TbetaR-II gene, all of which were 1 base deletion of 10 adenine repeats, were detected in 3 of 6 cancers, with MSI at 2 loci. However, mutations were not detected in 6 cancers, with MSI only at 1 locus and 31 cancers without MSI. Moreover, microanalysis in these cases revealed that the mutant-type alleles of TbetaR-II were invariably common in different areas within the tumor, in contrast to the markedly variable alleles of microsatellite loci. Our results suggest that frameshift mutation of the TbetaR-II gene may be a critical event associated with MSI and may contribute to carcinogenesis of the stomach. One of the possible mechanisms of escape from growth control by TGFbeta during gastric carcinogenesis could involve frameshift mutations of the TbetaR-II gene caused by DNA replication errors.     

Improved exercise tolerance after losartan and enalapril in heart failure: correlation with changes in skeletal muscle myosin heavy chain composition

BACKGROUND: In congestive heart failure, fatigue-resistant, oxidative, slow type I fibers are decreased in leg skeletal muscle, contributing to exercise capacity (EC) limitation. The mechanisms by which ACE inhibitors and AII antagonists improve EC is still unclear. We tested the hypothesis that improvement in EC is related to changes in skeletal muscle composition toward type I fibers. METHODS AND RESULTS: Eight patients with congestive heart failure, NYHA classes I through IV, were treated for 6 months with enalapril (E) 20 mg/d, and another 8 with losartan (L) 50 mg/d. EC was assessed with maximal cardiopulmonary exercise testing at baseline and after treatment. Myosin heavy chain (MHC) composition of the gastrocnemius was studied after electrophoretic separation of slow MHC1, fast oxidative MHC2a, and fast glycolytic MHC2b isoforms from needle microbiopsies obtained at baseline and after 6 months. EC improved in both groups. Peak V(O2) increased from 21.0+/-4.7 to 27.6+/-4.3 mL . kg-1 . min -1 (P=0.011) in the L group and from 17.5+/-5.0 to 25.0+/-5.5 mL . kg-1 . min -1 (P=0.014) in the E group. Similarly, ventilatory threshold changed from 15.0+/-4.0 to 19.9+/-4.9 mL (P=0. 049) with L and from 12.0+/-1.9 to 15.4+/-3.5 mL (P=0.039) with E. MCH1 increased from 61.2+/-11.2% to 75.4+/-7.6% with L (P=0.012) and from 60.6+/-13.1% to 80.1+/-10.9% (P=0.006) with E. Similarly, MHC2a decreased from 21.20+/-9.5% to 12.9+/-4.4% (P=0.05) with L and from 19.9+/-7.8% to 11.8+/-7.9% (P=0.06) with E. MHC2b changed from 17. 5+/-6.5% to 11.7+/-5.2% (P=0.07) with L and from 19.5+/-6.4% to 8. 1+/-4.6% (P=0.0015) with E. There was a significant correlation between net changes in MHC1 and absolute changes in peak V(O2) (r2=0.29, P=0.029) and a trend to significance for MHC2a and 2b. CONCLUSIONS: Six months' treatment with L and with E produces an improvement in EC of similar magnitude. These changes are accompanied by a reshift of MHCs of leg skeletal muscle toward the slow, more fatigue-resistant isoforms. Magnitude of MHC1 changes correlates with the net peak V(O2) gain, which suggests that improved EC may be caused by favorable biochemical changes occurring in the skeletal muscle.     

Computation of statistical functions in distributed information systems

The problem of parallel distributed computation of some commonly found statistical functions is considered.

Data are supposed to belong to a horizontally partitioned and possibly duplicated Distributed Database.

Results for Homogeneously and Nonhomogeneously Decomposable Functions are shown applied to the case of the most common built-in functions in Information Systems.