Simultaneous Determination of Isopyrazam and Azoxystrobin in Cucumbers by Liquid Chromatography-Tandem Mass Spectrometry.

A rapid and sensitive analytical method based on high-performance liquid chromatography-tandem mass spectrometry was developed and validated for the determination of isopyrazam (IZM) and azoxystrobin (AZT) in cucumbers. A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used as the pretreatment procedure. The samples were extracted with acetonitrile and cleaned up with octadecylsilyl silica (C18) and graphite carbon black. The proposed method resulted in satisfactory recovery of IZM and AZT (91.48 to 114.62%), and relative standard deviations were less than 13.1% at fortification concentrations of 1, 20, and 500 µg kg-1 (n = 3). The limits of quantification for IZM and AZT were 0.498 and 0.499 µg kg-1, respectively, which are far below the maximum residue level (0.5 mg kg-1) established for this type of sample. Matrix effects were also evaluated. This study established a sensitive and fast method for the detection of IZM and AZT in cucumber samples.

Unexpected hydrated ions in the detection of sodium adduct coumarins using electrospray tandem mass spectrometry.

A series of coumarins were analyzed using electrospray ionization quadrupole time-of-flight tandem mass spectrometry in the positive-ion mode. Unexpected hydrated ions ([M + H2O + Na]+) was observed upon collision-induced dissociation of the sodiated ions ([M + Na]+) of eight coumarins. Several factors which affected relative abundance of [M + H2O + Na]+ ions such as collision energy, concentration and solvent were investigated. None of them have effect on the relative abundance of [M + H2O + Na]+. However, the peak of hydrated ions was not detected in the further collision-induced dissociation of protonated ions of coumarins. Apigenin and Quercetin sharing similar benzopyrone structural unit with coumarins are selected for tandem mass spectrometry analysis. There were no hydrated ions in their tandem mass spectrometry spectra of the precursor [M + Na]+ ions. Thus, both coumarins and sodium were necessary for the formation of [M + H2O + Na]+. Together with the result that hydrated ions are not formed by hydrolysis reactions, a six-membered ring structure which involves with the formation of [M + H2O + Na]+ was presented. And D-labeling experiment indicates that the H2O molecule did not come from solvent.

The Prognostic Value of the iScore, the PLAN Score, and the ASTRAL Score in Acute Ischemic Stroke.

BACKGROUND: Disability and mortality represent the most relevant clinical outcomes after acute ischemic stroke. Recently, a number of prognostic models of acute ischemic stroke have been developed, but they have not been extensively validated. In this study, we evaluated the ability of 3 prognostic models including the iScore, the PLAN score, and the ASTRAL score in predicting clinical poor outcomes or mortality at 6 months in patients with acute ischemic stroke. METHODS: A total of 323 patients were divided into a good-prognosis group and a poor-prognosis group based on the modified Rankin Scale. Model discrimination was quantified by calculating the area under the receiver operating characteristic (ROC) curve, and calibration was assessed by Hosmer-Lemeshow goodness of fit test and Pearson correlation coefficient. RESULTS: We identified 96 (29.7%) patients with poor prognosis, including 21 who were dead. All 3 models showed good ability in predicting poor prognosis and mortality in patients with acute ischemic stroke (all ROC > .70). There was no difference between these 3 models in terms of sensitivity and accuracy (all P > .05). CONCLUSIONS: The results of this study suggest that the iScore, the PLAN score, and the ASTRAL score were equal in predicting 6-month poor prognosis and mortality in patients with acute ischemic stroke. Overall, there was a very high correlation between observed and expected outcomes at the risk score level.

What is the destiny of a threatened fish, Ptychobarbus chungtienensis, now that non-native weatherfishes have been introduced into Bita Lake, Shangri-La?

Biological invasion is a pervasive negative force of global change, especially in its effects on sensitive freshwater ecosystems. Even protected areas are usually not immune. Ptychobarbus chungtienensis is a threatened freshwater fish now almost confined to Bita Lake, in the Shangri-La region of Yunnan province, China. Its existence is threatened by the introduction of non-native weatherfishes (Misgurnus anguillicaudatus and Paramisgurnus dabryanus) by an unusual method known as 'prayer animal release'. Periodic surveys revealed the ratio of invasive weatherfishes to P. chungtienensis has been increasing since the former species was first recorded from the lake in August, 2009. Ptychobarbus chungtienensis shows low genetic diversity in the relict Lake Bita population. Weatherfishes, however, have highly successful survival strategies. The degree of dietary overlap between the species is alarming and perhaps critical if food is found to be a limiting factor.

[Impacts of Microorganisms on Degradation and Release Characteristics of Organic Phosphorus in Lake Sediments During Freezing Season].

Organic phosphorus (OP) has been considered as an important pool for bioavailable phosphorus. In this work, impacts of microorganisms on the degradation and release of OP in sediments from Lake Wuliangsuhai during freezing season were investigated using chemical sequential extraction methods. The results showed that the concentrations of dissolved total phosphorus (DTP) dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) in overlying water of the sterilization (T(N)) treatments were higher than those of the substrate addition (T(M)) treatments, indicating that the assimilation of anaerobic microorganisms and the disassimilation reduction of iron driven by microorganisms were the main mechanisms govening OP behavior and process across the water-sediments interface. The concentrations of labile OP (LOP) and total labile phosphorus (TLP) decreased during the releasing period. During the first 60 days, the concentrations of moderately labile OP (MLOP) of T(M) treatments decreased, while those of the nonlabile OP (NLOP) increased. During 60-180 days, the MLOP concentrations of T(M) treatments were found increasing, while those of NLOP decreased. During the beginning period (0-60 d), the concentrations of MLOP of T(M) treatments were higher than those of T(N) treatments, while the NLOP concentrations were lower than those of T(N) treatments; and these trends were reversed during 60-180 days. These trends revealed the possibility of transformation between MLOP and NLOP during the releasing process. Furthermore, the percentage of OP was found decreasing, while inorganic phosphorus (IP) of T(M) treatments increased, which indicated the transfromation trend from OP to IP (about 6.1% of OP was transformed to IP) in sediments. On the basis of this work, it can be conclueded that microorganisms can improve the transformation from OP to IP elevating the bioavailability and contribution of OP in the eutrophication process of Iakes.

[Exchange Fluxes and Coupling Relationship of Dissolved Inorganic Carbon and Dissolved Organic Carbon Across the Water-Sediment Interface in Lakes].

In this work, the exchange fluxes and coupling relationship of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) were investigated across the water-sediment interface in Lake Wuliangsuhai and Daihai by employing columnar simulation method. The results showed that the sediments in non-Phragmitescommunis area from Lake Wuliangsuhai functioned as the sources of DIC and DOC for overlying water, whereas the sediments from Lake Daihai as the sinks during the period of summer (90 days). In the experimental period, the average exchange rates of DIC and DOC were 71.07 mmol x (m2 x d)(-1) and 185.09 mmol x (m2 x d)(-1) in non-Phragmitescommunis area from Lake Wuliangsuhai, respectively; while in Lake Daihai, they were 155.75 mmol x (m2 x d)(-1) and -1478.08 mmol x (m2 x d)(-1) in shoal water zone, and -486.53 mmol x (m2 x d)(-1) and -1274.02 mmol x (m2 x d)(-1) in deep water zone, respectively. The coupling effects between DIC and DOC were governed by hydrobios, microbial uptake, abiotic and microbiological degradation in Lake Wuliangsuhai and in shoal water zone of Lake Daihai; while they were closely related to the coprecipitation process of CaCO3 and the fraction distribution of inorganic carbon in sediments in deep water zone of Lake Daihai. In summary, the sink or source functions of sediments could be considered as the results of synthetic action of lake types, offshore distance, geohydrochemistry and the fraction distribution of inorganic carbon.

Morphological and molecular studies on Garra imberba and its related species in China.

Garra imberba is widely distributed in China. At the moment, both Garra yiliangensis and G. hainanensis are treated as valid species, but they were initially named as a subspecies of G. pingi, a junior synonym of G. imberba. Garra alticorpora and G. nujiangensis also have similar morphological characters to G. imberba, but the taxonomic statuses and phylogenetic relationships of these species with G. imberba remains uncertain. In this study, 128 samples from the Jinshajiang, Red, Nanpanjiang, Lancangjiang, Nujiang Rivers as well as Hainan Island were measured while 1 mitochondrial gene and 1 nuclear intron of 24 samples were sequenced to explore the phylogenetic relationship of these five species. The results showed that G. hainanensis, G. yiliangensis, G. alticorpora and G. imberba are the same species with G. imberba being the valid species name, while G. nujiangensis is a valid species in and of itself.

[Effect of dexamethasone on expressions of TWEAK and Fn14 in the lung of asthmatic mice].

AIM: To investigate the effect of dexamethasone (Dex) on the expressions of TNF-like weak inducer of apoptosis (TWEAK) and fibroblast growth factor-inducible immediate-early response protein 14 (Fn14) in the lung of asthmatic mice. METHODS: Ovalbumin (OVA) was used to induce asthma in BALB/c mice. Thirty-six female mice were randomly divided into control group (n=12), asthmatic group (n=12) and Dex treated group (n=12). The airway inflammation was evaluated by HE staining. The expressions of TWEAK and Fn14 at mRNA and protein levels were detected by RT-PCR and immunohistochemistry, respectively. RESULTS: Both mRNA and protein levels of TWEAK and Fn14 in the asthmatic model group were significantly higher than those of control group (P<0.01), and both mRNA and protein levels of TWEAK and Fn14 in the Dex treated group were significantly lower than those of asthmatic group (P<0.01). CONCLUSION: Dex can reduce the airway inflammation through inhibiting the expressions of TWEAK and Fn14.

[Influence of platform switching on crest bone maintenance around implants: a radiographic investigation in dogs].

PURPOSE: To evaluate and compare the dynamic changes in functional loading or non-functional loading with platform-switching (PLS) implants and butt-joint implants,and to refine the factors leading to marginal bone loss around PLS. METHODS: Six adult dogs were selected and numbered randomly.The second,third and fourth premolars in bilateral mandible of each dog were extracted. After 3 months, the implantation operation was carried out. There were 3 kinds of implants, 36 implants in total, which were divided in to 3 groups: Group A,Group G and Group U. In particular order, A, G and U were placed on each side of every dog. Three months later, the 2nd surgery was begun. At the 4th month from the 1st surgery, for each dog, on the right side only, the abutments were installed and impression was taken. Then, after 2 weeks, the dental prostheses were put on. All dogs were executed at the end of the 12th month. X-ray film was taken at the 3rd, 6th, 9th and 12th month and the moment of the 1st surgery (baseline). Measurements were made between the implant shoulder (IS),the most coronal level of bone in contact with implant (CLB), and the level of alveolar bone crest (BC). According to the different groups of implants (A, G, U), all records were analyzed with paired and Wilcoxon's signed rank test using SPSS11.5 software package. RESULTS: The mean IS-CLB and IS-BC values of group A, G were significantly different with those of group U at the 6th, 9th and 12th month, while there was no significant difference between group A and G. No matter they were loading or not, the self-comparison of each kind of implant presented no significant difference. There was no significant difference between every kind of implant on their self-comparison during the first three months; while, the differences were significant during the next 9 months. CONCLUSIONS: The most significant changes in the absorption of marginal bone around two stage submerged implant can be observed after 3 months of implanting. The bone absorption was not related to functional loading or not.

Arabidopsis AtVPS15 plays essential roles in pollen germination possibly by interacting with AtVPS34.

VPS15 protein is a component of the phosphatidylinositol 3-kinase complex which plays a pivotal role in the development of yeast and mammalian cells. The knowledge about the function of its homologue in plants remains limited. Here we report that AtVPS15, a homologue of yeast VPS15p in Arabidopsis, plays an essential role in pollen germination. Homozygous T-DNA insertion mutants of AtVPS15 could not be obtained from the progenies of self-pollinated heterozygous mutants. Reciprocal crosses between atvps15 mutants and wild-type Arabidopsis revealed that the T-DNA insertion was not able to be transmitted by male gametophytes. DAPI staining, Alexander's stain and scanning electron microscopic analysis showed that atvps15 heterozygous plants produced pollen grains that were morphologically indistinguishable from wild-type pollen, whereas in vitro germination experiments revealed that germination of the pollen grains was defective. GUS staining analysis of transgenic plants expressing the GUS reporter gene driven by the AtVPS15 promoter showed that AtVPS15 was mainly expressed in pollen grains. Finally, DUALmembrane yeast two-hybrid analysis demonstrated that AtVPS15 might interact directly with AtVPS34. These results suggest that AtVPS15 is very important for pollen germination, possibly through modulation of the activity of PI3-kinase.

[Clinical study of transcrestal maxillary sinus floor elevation with the disk-up sinus reamer].

OBJECTIVE: To evaluate the clinical effect of the disk-up sinus reamer (DSR) applied to transcrestal maxillary sinus floor elevation with simultaneous placement of implants. METHODS: Thirty-seven patients underwent transcrestal maxillary sinus floor elevation with fifty-one implants placed simultaneously using the DSR. The residual bone height (RBH) was 3 to 8 mm, (5.61 ± 1.61) mm on average. The safety of this technique and the pain index during the operation was evaluated. The final prostheses were restored in 3-6 months postoperatively. The follow-up period was 3 to 24 months. The stability and osseointegration of the implants were clinically evaluated, and the endo-sinus bone gain around the implants were measured. RESULTS: The elevation height ranged from 2 to 8 mm, with an average of (4.75 ± 1.55) mm. There was no detectable sinus membrane perforation, no serious suffering or uncomfortable subjective sensation in any patients during operation with a pain index of (2.22 ± 0.98). During the follow-up period, no sinus complication was observed. Favorable osseointegration was obtained. There were no implants or prostheses which were loose or lost. The survival rate was 100%. The radiographic results demonstrated that the endo-sinus bone gain tended to reach stabilization after 6 months and the marginal bone loss was (1.20 ± 0.72) mm after 12 months. CONCLUSIONS: Transcrestal maxillary sinus floor elevation with simultaneous implant placement by DSR is a safe, invasive and handy technique, with higher elevation height, fewer clinical complications and less pain. It shows satisfactory clinical results in short term and a long-term observation is still needed.

Pyrimidinyl-substituted amides and thioureas: syntheses, crystal structure and herbicidal activities.

BACKGROUND: The high herbicidal activities of [1,2,4]triazolo[1,5-c]pyrimidine and 2H-1,2,4-thiadiazolo[2,3-a]pyrimidine derivatives suggested the development of new fused heterocyclic compounds for application as herbicides. RESULTS: Three series of pyrimidinyl-substituted thioureas (4) and amides (5, 6) were synthesized, and the typical crystal structure of a 2H-1,2,4-thiadiazolo[2,3-a]pyrimidine derivative (5a) was determined by X-ray diffraction. All the compounds were tested for herbicidal activity against selected weeds. CONCLUSION: The series of fused heterocyclic amides 5a to 5d exhibited high herbicidal activities both against monocotyledonous weeds (Echinochloa crus-galli L., Sorghum bicolor (L.) Mönch., Digitaria sanguinalis (L.) Scop) and against dicotyledonous weeds (Amaranthus retroflexus L. and Brassica campestris L.) in pre-emergence treatments. In particular, compound 5b at low concentration still showed high inhibitory activity against A. retroflexus in pre-emergence treatment. Different substituents at the meta positions of the pyrimidine ring were found to affect the herbicidal activity.

Geometry of elytra opening and closing in some beetles (Coleoptera, Polyphaga).

Elytra in beetles move actively, driven by their own muscles, only during transient opening and closing. The kinematics of these movements have been inadequately described, sometimes controversially. Our goal was a quantitative 3-D description of diverse active movements of the elytra, in terms of directions of the axes of elytra rotation. Broad opening and closing was video recorded in beetles, tethered by the mesothorax, and has been analyzed frame by frame. For tracing, small dots or straw arms were glued to the elytra. Opening and closing traces coincided. The trace of the elytron apex was a flat circular arc about the axis of abduction-adduction (AAA). The rising hemiaxis pointed contralaterad. The AAA was tilted forwards in Melolontha hippocastani, Allomyrina dichotoma and Prionus coriarius but backwards in Chalcophora mariana. In Cetonia aurata, the AAA had a low elevation and a strong backward orientation. If another elytra-fixed point was traced in addition to the apex (in M. hippocastani and P. coriarius), then secondary rotation about the sutural edge (supination on opening) occurred. Modeling of abduction-adduction revealed that the elytron rose on opening if the AAA pointed contralaterad. The more the AAA was tilted forward, the more negative was the attack angle of the open elytra. The negative attack angle was partly compensated by positive body pitch and, more effectively, by supination of the costal edge about the sutural edge. The initial stage of opening included elevation of closed elytra (by 10-12 degrees) and partition to the sides, combined with an inward turn (<2-3 degrees). Axis of rotation at this stage presumably coincided with the AAA. Movement of one elytron with respect to the opposite one at the beginning of opening followed the shallow arc convex down. The geometry of this relative movement describes the initial partition of the elytra and release of the sutural lock.