Analysis of Microbial Diversity and Community Structure of Rhizosphere Soil of Three Astragalus Species Grown in Special High-Cold Environment of Northwestern Yunnan, China.

Astragalus is a medicinal plant with obvious rhizosphere effects. At present, there are many Astragalus plants with high application value but low recognition and resource reserves in the northwestern area of Yunnan province, China. In this study, metagenomics was used to analyze the microbial diversity and community structure of rhizosphere soil of A. forrestii, A. acaulis, and A. ernestii plants grown in a special high-cold environment of northwestern Yunnan, China, at different altitudes ranging from 3225 to 4353 m. These microbes were taxonomically annotated to obtain 24 phyla and 501 genera for A. forrestii, 30 phyla and 504 genera for A. acaulis, as well as 39 phyla and 533 genera for A. ernestii. Overall, the dominant bacterial phyla included Proteobacteria, Actinobacteria, and Acidobacteria, while the dominant fungal ones were Ascomycota and Basidiomycota. At the genus level, Bradyrhizobium, Afipia, and Paraburkholderia were the most prevalent bacteria, and Hyaloscypha, Pseudogymnoascus, and Russula were the dominant fungal genera. Some of them are considered biocontrol microbes that could sustain the growth and health of host Astragalus plants. Redundancy analysis revealed that pH, TN, and SOM had a significant impact on the microbial community structures (p < 0.05). Finally, triterpene, flavonoid, polysaccharide, and amino acid metabolisms accounted for a high proportion of the enriched KEGG pathways, which possibly contributed to the synthesis of bioactive constituents in the Astragalus plants.

[Pregnant Outcomes of Multiparae in Women with Advanced Age (≥35 years)after the 2008 Wenchuan Earthquake].

OBJECTIVE: To evaluate pregnancy outcomes of multiparae in women with advanced age (≥35 yr.) after the 2008 Wenchuan earthquake. METHODS: Clinical data of 542 pregnant women with prenatal care in Wenchuan during 20082013 were reviewed,comparing preconception conditions,pregnant rates,pregnant complications,and perinatal outcomes between those younger ( n=176) and older ( n=366) than 35 years. RESULTS: In the 542 women,622 conceptions were reported,with 517 deliveries and 522 live births. The women with advanced age had lower cumulative pregnancy rate (twoyear),higher incidence of hypertensive disorders of pregnancy,gestational diabetes,multiple pregnancy,fetal distress,low birth weight and birth defects than their younger counterparts. The younger women also had higher term live birth rate and lower miscarriage rate. But the differences showed no statistical significance. CONCLUSION: Prenatal care brings similar pregnant outcomes to multiparae in women with advance aged and younger aged.

Filling the Missing Links of M3n Prototype 3d-4f and 4f Cyclic Coordination Cages: Syntheses, Structures, and Magnetic Properties of the Ni10Ln5 and the Er3n Wheels.

In this paper, we proposed a number rule for 3d-4f and 4f cyclic coordination cages (CCCs); that is, CCCs consisting of vertex-sharing M4(µ3-OH)4 (M = 3d transition metal or 4f lanthanide ions) units should have 3 × n metal centers (abbreviated M3n), where n represents the number of the M4(µ3-OH)4 subunits. Under this number rule we reasoned that some species of CCCs, for example, the pentadecanuclear 3d-4f wheel and the pure 4f wheels with 9 or 18 centers, should practically have existed. However, there are no such complexes reported in the literature. To realize such CCCs we employed a mixed-ligand approach, that is, to simultaneously use the primary and the ancillary ligands for syntheses. This approach successfully leads to the isolation of two families of CCCs, namely, the Ni10Ln5 (Ln = Gd and Y) mixed-metal wheels and the Er3n (n = 4, 5, and 6) pure 4f metal wheels. These two families of CCCs unambiguously fill the missing links of the M3n prototype CCCs. Moreover, dominated ferromagnetic interaction indicates high ground-spin state for the Gd5Ni10 wheel. The ferromagnetic interactions between the nickel centers are verified using the diamagnetic Y(III) analogue, which reveals an averaged coupling constant (J = 2.7 cm-1), while accompanied by a large negative zero-field splitting parameter (D = -6.1 cm-1) for single Ni(II) ions. Interestingly, the Y(III)-diluted Er12 wheel shows slow magnetic relaxation behavior, presumably indicating the magnetically anisotropic nature of the erbium(III) ions.

Topological Self-Assembly of Highly Symmetric Lanthanide Clusters: A Magnetic Study of Exchange-Coupling "Fingerprints" in Giant Gadolinium(III) Cages.

The creation of a perfect hollow nanoscopic sphere of metal centers is clearly an unrealizable synthetic challenge. It is, however, an inspirational challenge from the viewpoint of chemical architecture and also as finite molecular species may provide unique microscopic insight into the origin and onset of phenomena such as topological spin-frustration effects found in infinite 2D and 3D systems. Herein, we report a series of high-symmetry gadolinium(III) (S = 7/2) polyhedra, Gd20, Gd32, Gd50, and Gd60, to test an approach based on assembling polymetallic fragments that contain different polygons. Structural analysis reveals that the Gd20 cage resembles a dodecahedron; the vertices of the Gd32 polyhedron exactly reveal symmetry Oh; Gd50 displays an unprecedented polyhedron in which an icosidodecahedron Gd30 core is encapsulated by an outer Gd20 dodecahedral shell with approximate Ih symmetry; and the Gd60 shows a truncated octahedron geometry. Experimental and theoretical magnetic studies show that this series produces the expected antiferromagnetic interaction that can be modeled based on classical spins at the Gd sites. From the magnetization analyses, we can roughly correlate the derivative bands to the Gd-O-Gd angles. Such a magneto-structural correlation may be used as "fingerprints" to identify these cages.

Metallacrowns as Templates for Diabolo-like {LnCu8 } Complexes with Nearly Perfect Square Antiprismatic Geometry.

A series of diabolo-like nonanuclear {LnIII CuII8 } (Ln=Tb, Dy, Ho, Er, Tm, Yb, and Y) clusters were prepared in which the LnIII ion is capped by two 8-MC-4 metallacrown ligands to form a nearly ideal square antiprismatic (SAP) coordination geometry with D4d symmetry. Despite the lack of crystallographic symmetry, these molecules engender the lanthanide ions with highly axial mJ states. The axial/equatorial nature of the crystal field in environments close to ideal SAP geometry is very subtle and influenced by the nature of the ligand lone pairs. Slow magnetic relaxation behaviour was observed for the DyIII , ErIII , TmIII , and YbIII analogues, and the obtained effective energy barriers are not consistent with excitations on the LnIII ion, suggesting a more nuanced situation.

Dy(iii)-Carboxylate chain containing quasi-D5h sites exhibits enhanced energy barrier for magnetization reversal.

A slight modification of the coordinating solvent molecule induced a change in the local symmetry at one of the metal sites of a Dy(iii)-carboxylate chain complex from quasi-D5h (hepta-coordinated) to C2v (octa-coordinated). This afforded an effective energy barrier for magnetization reversal, which was significantly changed from 403.6 K (diluted) to about 7.5 K.

Effects of CYP3A4 polymorphisms on efficiency of general anesthesia combined with epidural block in patients undergoing cardiac valve replacement.

This study aims to investigate the effects of CYP3A4 polymorphisms (*4, *5 and *6) on efficiency of general anesthesia (GA) combined with epidural block (EB) in patients undergoing cardiac valve replacement. From January 2014 to October 2015, a total of 511 patients undergoing cardiac valve replacement (case group) and 503 healthy individuals (control group) were selected for the study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied for genotyping of CYP3A4 gene. Central venous pressure (CVP), mean arterial pressure (MAP), heart rate (HR), pulse oximetry (SPO2), extubation and duration of intensive care unit (ICU) stay during the surgery were observed and recorded. A nine-month follow-up was conducted. Genotype and allele frequency of CYP3A4*4 were significantly different between the case and control groups (all P < 0.05). Compared with wild-type *1*1 patients with heterozygous *1*4 of CYP3A4*4 showed significant difference in HR, MAP, SPO2 and CVP and in the time of extubation and ICU stay. CYP3A4*4 polymorphism may be associated with the effect of GA combined with EB in cardiac surgery. These results demonstrate that CYP3A4*4 polymorphism is correlated with the effects of GA combined with EB in cardiac surgery. CYP3A4 polymorphisms increase the risk of GA combined with EB among patients undergoing cardiac valve replacement.

Hydrophobicity-Driven Self-Assembly of an Eighteen-Membered Honeycomb Lattice with Almost Classical Spins.

The design and synthesis of model compounds that do not exist naturally is one of the important targets in modern coordination chemistry. Herein, an eighteen-membered honeycomb structure with equal numbers of MnII (s=5/2) and GdIII (s=7/2) metal centers has been prepared, for the first time, by using a hydrophobic force-directed self-assembling process. Due to the weakly coupled GdIII pairs, the magnetic properties are mainly determined by eight-membered chains in the experimentally considered temperature range. These [Mn4 Gd4 ] "finite-size" chains, albeit with large Hilbert space, can be fully resolved by the high-temperature series expansion and the powerful finite-temperature Lanczos method, which reveal that the exchange-couplings between the metal centers are antiferromagnetic and consistent with the magnetization measurement. Interestingly, from the surface-engineering point of view, the [Mn4 Gd4 ] chains are "precisely" assembled into a 2D honeycomb pattern, which is potentially desirable in the design of weakly coupled qubits.

Characteristic fragmentation behavior of tobacco-specific N-nitrosamines using electrospray ionization multistage tandem mass spectrometry incorporating deuterium labeling.

RATIONALE: Tobacco-specific N-nitrosamines (TSNAs) mainly include 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-nitrosonornicotine (NNN), N-nitrosoanabasine (NAB) and N-nitrosoanatabine (NAT) that are formed from tobacco alkaloids during the curing process and contained in tobacco and tobacco smoke. They are linked with carcinogenesis. Analytical methods for quality control of products and determination of their metabolites are therefore of great importance. METHODS: The characteristic fragmentation behaviors of tobacco-specific TSNAs have been studied by electrospray ionization multistage tandem mass spectrometry. The deutero-labeled TSNA compounds have also been employed to clarify the fragmentation mechanism, which further confirms the proposed fragmentation patterns. RESULTS: Detailed analysis of the resultant fragments shows there are two different kinds of fragmentation patterns with the general fragment backbone of pyrrolidine or piperidine rings. In one route, pyrrolidine or piperidine rings undergo direct fragmentation and form some stable intermediates without affecting the parent rings. The other, however, involves ring opening and then ring closure at the pyridine-2 carbon atom to form multi-membered rings. CONCLUSIONS: This characteristic fragmentation behavior therefore provides useful information on identification of TSNAs that may be used to monitor such kinds of compound in the biological metabolism.

Post-harvest induced production of salvianolic acids and significant promotion of antioxidant properties in roots of Salvia miltiorrhiza (Danshen).

Danshen, the dried roots of Salvia miltiorrhiza, is an extremely valued Traditional Chinese Medicine. Previously, we have demonstrated that salvianolic acid B (SaB), the important bioactive ingredient in this herb, was a post-harvest product. Here, we further reported that all salvianolic acids (SAs) in the roots were post-harvest products of the drying process. In addition, the results of various radical scavenging activity assays, including lipid peroxidation (1), DPPH (2), hydroxyl (3) and superoxide (4), were significantly increased along with the accumulation of total salvianolic acids in the process. The contents of chemical targets and antioxidant activities both reached the highest value under thermal treatment at 130 °C for 80 min. In this dehydration period, contents of SaB, and sum of nine SAs increased from 0.01% to 5.51%, and 0.20% to 6.61%; and IC50 of antioxidant activity decreased from 4.85 to 2.69 (1); 7.75 to 0.43 (2); 2.57 to 1.13 (3) and 17.25 to 1.10 mg/mL. These results further supported the hypothesis that the newly harvested plant roots were still physiologically active and the secondary metabolites might be produced due to dehydration stress after harvest. Our findings supplied an important and useful theoretical basis for promoting the quality of Danshen and other medicinal plant materials.

A rapid and sensitive method for hydroxyl radical detection on a microfluidic chip using an N-doped porous carbon nanofiber modified pencil graphite electrode.

Hydroxyl radicals (˙OH) play an important role in human diseases. Traditional detection methods are time consuming and require expensive instruments. Here, we present a simple and sensitive method for the detection of hydroxyl radicals on a microfluidic chip using an electrochemical technique. Aniline monomer is electrochemically polymerized on the surface of a pencil graphite electrode and carbonized at 800 °C. The resulting N-doped porous carbon nanofiber-modified pencil graphite electrode is embedded into a microfluidic chip directly as a working electrode. 4-Hydroxybenzoic acid (4-HBA) is selected as the trapping agent owing to its unique 3,4-DHBA product and high trapping efficiency. A low detection limit of 1.0 × 10(-6) M is achieved on the microfluidic chip. As a demonstration, the microfluidic chip is successfully utilized for the detection of ˙OH in cigarette smoke. The strong π-π stacking and hydrophobic interactions between the nitrogen-doped carbon materials and the pencil graphite make the modified electrode well-suited for the microfluidic chip.

Core-shell Ag@SiO(2) nanoparticles concentrated on a micro/nanofluidic device for surface plasmon resonance-enhanced fluorescent detection of highly reactive oxygen species.

A micro/nanofluidic device integrating a nanochannel in a microfluidic chip was developed for sensitive fluorescent determination of highly reactive oxygen species (hROS) enhanced by surface plasmon resonance-enhanced fluorescence (SPREF). The nanochannel was simply fabricated by polyaniline nanostructures modified on a glass slide. Core-shell Ag@SiO2 nanoparticles were concentrated in front of the nanochannel for fluorescence enhancement based on the SPREF effect. As a demonstration, hROS in the mainstream of cigarette smoke (CS) were detected by the present micro/nanofluidic device. The fluorescent probe for trapping hROS in puffs of CS employed a microcolumn that was loaded with a composite of DNA (conjugated fluorophores, FAM) and Au membrane (coated on cellulose acetate). With a laser-induced fluorescence detection device, hROS was determined on the basis of the amount of FAM groups generated by DNA cleavage. With the optimization of the trapping efficiency, we detected about 4.91 pmol of hROS/puff in the mainstream CS. This micro/nanofluidic-SPREF system promises a simple, rapid, and highly sensitive approach for determination of hROS in CS and other practical systems.

Sensitive determination of reactive oxygen species in cigarette smoke using microchip electrophoresis-localized surface plasmon resonance enhanced fluorescence detection.

A sensitive approach to the determination of reactive oxygen species (ROS) in puffs of cigarette smoke (CS) has been developed. The experimental system consists of a microfluidic chip electrophoresis and a laser induced fluorescence (LIF) device enhanced by localized surface plasmon resonance. Core-shell Ag@SiO2 nanoparticles were prepared and then immobilized on the surface of the microchannel to increase the fluorescence intensity based on localized surface plasmon resonance-enhanced fluorescence (LSPREF) effect. The ROS in puffs of CS were trapped via the oxidation of 2',7'-dichlorodihydrofluorescein (DCHF) that had been loaded on polyacrylonitrile (PAN) nanofibers in a micro-column. Determination of ROS was based on the amount of 2',7'-dichlorofluorescein (DCF), which is the sole product from DCHF oxidation. With the optimization of the trapping efficiency, we detected about 8.0 pmol of ROS per puff in the mainstream CS. This microchip electrophoresis-SPREF system enables sensitive quantitation of ROS in CS with low consumption of reagent, material, and analysis time.

Molecule-based magnetic coolers.

There has been a rapid expansion in the use of molecular magnets for both low- and ultra low-temperature cooling applications in recent years, and here we review the chemical variation and magnetothermal properties of reported molecular coolers, structuring the review by structural dimensions, metal-ions involved and ligands employed. This review provides an overview of the developments in designing better low-temperature magnetic refrigerants, and includes description of new 3D-materials that, in some ways, out-perform traditional magnetic coolants. Thus, this review should serve as both a tutorial for many newcomers and a summary of progress for researchers who are active in the field.

Genetic variation in alkaloid accumulation in leaves of Nicotiana.

Alkaloids are plant secondary metabolites that are widely distributed in Nicotiana species and contribute greatly to the quality of tobacco leaves. Some alkaloids, such as nornicotine and myosmine, have adverse effects on human health. To reduce the content of harmful alkaloids in tobacco leaves through conventional breeding, a genetic study of the alkaloid variation among different genotypes is required. In this study, alkaloid profiles in leaves of five Nicotiana tabacum cultivars and Nicotiana tomentosiformis were investigated. Six alkaloids were identified from all six genotypes via gas chromatograph-mass spectrometry (GC-MS). Significant differences in alkaloid content were observed both among different leaf positions and among cultivars. The contents of nornicotine and myosmine were positively and significantly correlated (R(2)=0.881), and were also separated from those of other alkaloids by clustering. Thus, the genotype plays a major role in alkaloid accumulation, indicating a high potential for manipulation of alkaloid content through traditional breeding.

Production of salvianolic acid B in roots of Salvia miltiorrhiza (Danshen) during the post-harvest drying process.

Drying is the most common and fundamental procedure in the post-harvest processing which contributes to the quality and valuation of medicinal plants. However, attention to and research work on this aspect is relatively poor. In this paper, we reveal dynamic variations of concentrations of five major bioactive components, namely salvianolic acid B (SaB), dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA, in roots of Salvia miltiorrhiza (Dashen) during the drying process at different oven temperatures. A minor amount of SaB was found in fresh materials while an noticeable increase in SaB was detected in drying at 50~160 °C. The maximal value occurred after 40 min of drying at 130 °C and its variation showed a reverse V-shaped curve. Production of SaB exhibited a significant positive correlation with drying temperatures and a significant negative correlation with sample moistures. The amounts of tanshinones were nearly doubled in the early stage of drying and their variations showed similar changing trends with drying temperatures and sample moistures. The results supported our speculation that postharvest fresh plant materials, especially roots, were still physiologically active organs and would exhibit a series of anti-dehydration mechanisms including production of related secondary metabolites at the early stage of dehydration. Hence, the proper design of drying processes could contribute to promoting rather than reducing the quality of Danshen and other similar medicinal plants.

A meta-analysis of the value of fluorodeoxyglucose-PET/PET-CT in the evaluation of fever of unknown origin.

BACKGROUND AND PURPOSE: The diagnosis of patients with fever of unknown origin (FUO) remains a challenging medical problem for internal medicine. A reliable estimate of the diagnostic performance of FDG-PET and FDG-PET/CT in the assessment of FUO unidentified by conventional workup has never been systematically assessed, and present systematic review was aimed at this issue. METHODS: A systematic search for relevant studies was performed of the PubMed, Embase, and Cochrane databases. Methodological quality of each study was assessed. Sensitivity, specificity and area under the curve (AUC) were meta-analyzed. Subgroup analyses were performed if results of individual studies were heterogeneous. RESULTS: The inclusion criteria were met by nine studies. Overall, the studies had good methodological quality. Pooled sensitivity and specificity of FDG-PET for the detection of FUO were 0.826 (95% CI; 0.729-0.899) and 0.578 (95% CI; 0.488-0.665), respectively, and the AUC was 0.810. Heterogeneity among the results of FDG PET studies was present (QSE=12.40, I2=67.7%; QSp=35.98, I2=88.9%). Pooled sensitivity and specificity of FDG-PET/CT were 0.982 (95% CI; 0.936-0.998) and 0.859 (95% CI; 0.750-0.934), respectively, and the AUC was 0.947. We did not find any statistical differences in the AUC and Q* index between FDG-PET and FDG-PET/CT (Z=0.566, p>0.05). CONCLUSIONS: Although the FDG-PET studies that we examined were heterogeneous, FDG-PET appears to be a sensitive and promising diagnostic tool for the detection of the causes of FUO. FDG-PET/CT should be considered among the first diagnostic tools for patients with FUO in whom conventional diagnostics have been unsuccessful.

[Cyto-genotoxicity induced by cigarette smoke condensates in human peripheral blood lymphocytes in vitro].

OBJECTIVE: To investigate the cyto-genotoxicity of cigarette smoke condensates (CSCs) in human peripheral blood lymphocytes with different assays in vitro. METHODS: Human lymphocytes were exposed to particle matter of cigarette smoke combined with or without S9 mixtures at doses of 25, 50, 75, 100 and 125 microg/ml for 3 h. The cytotoxicity induced by CSCs was detected by CCK-8 assay. The DNA damage, DNA repair (repair time: 30, 60, 90, 120 and 240 min, respectively) and the somatic cell mutations induced by 75 microg/ml CSCs were measured by comet assay, hprt gene and TCR gene mutation tests, respectively. RESULTS: CCK-8 assay indicated that the cell viability decreased with CSCs doses. At the doses of 100, 125 microg/ml, the cell viability of CSCs +S9 group was significantly higher than that of CSCs -S9 group (P < 0.05, P < 0.01). In comet assay, DNA damage significantly increased in a dose-dependent manner, as compared with controls (P < 0.01). Moreover, there was significant difference between -S9 group and +S9 group (P < 0.05, P < 0.01). The Mf-TCR at each dose group was significantly higher than that of controls (P < 0.05, P < 0.01). The Mf-hprt at high-dose groups were significantly higher than that of controls (P < 0.01), and significant difference of Mf-TCR and Mf-hprt at high doses of CSCs between -S9 group and +S9 group (P < 0.05, P < 0.01). The DNA damage induced by CSCs +S9 or CSCs -S9 could be repaired, but DNA repair speed was different between -S9 group and +S9 group (P < 0.05, P < 0.01). CONCLUSION: CSCs may induce cyto-genotoxicity in human peripheral blood lymphocytes in vitro, but S9 mix could reduce the toxicity of CSCs and impact DNA repair speed.

A simple electrochemical method for the determination of hydroxyl free radicals without separation process.

Generally speaking, measurement of hydroxylated radical products of salicylic acid requires a fussy separation process. In this study, we describe a simple method to electrochemically detect hydroxyl radicals (*OH) using 4-hydroxybenzoic acid (4-HBA) as the *OH trap. The *OH is generated by the Fenton reaction from iron (II) sulfate and hydrogen peroxide in a phosphate buffer solution. Experimental results show that our method can detect the OH with high sensitivity without any separation process. The differential pulse voltammetric responses show a linear dependence on the concentration of *OH in a range of 2.0x10(-6) and 1.0x10(-3)M with a determination limit down to 5.0x10(-7)M. As a demonstration, the kinetics of the Fenton reaction was mapped by measuring the reaction product of hydroxyl radical trapped by 4-HBA. The result is in good agreement with that reported previously. All the results show that the present approach could provide a simple, inexpensive and promising method for biomedicine and iatrology.