Realizing degree sequences with graphs having nowhere-zero 3-flows

The following open problem was proposed by Archdeacon: Characterize all graphical sequences π such that some realization of π admits a nowhere-zero 3-flow. The purpose of this paper is to resolve this problem and present a complete characterization: A graphical sequence π = (d I,d2,...,dn) with minimum degree at least two has a realization that admits a nowhere-zero 3-flow if and only if π ≠ (34,2), (k,3k), (k2,3k-1), where k is an odd integer. © 2008 Society for Industrial and Applied Mathematics.published_or_final_versio

Inhibitory mechanism of 3-hydroxypropionaldehyde accumulation in 1,3-propanediol synthesis with Klebsiella pneumoniae

3-Hydroxypropionaldehyde accumulation may cause the cessation of 1,3-propanediol sustained production with glycerol by Klebsiella pneumoniae. The impeller tip speed shift from higher to lower speed at glycerol excess or the pulsed glycerol feeding could lead to an abrupt increase of the 3- hydroxypropionaldehyde concentration (up to 10 mmol/l) in 10 min. The intracellular consequence of the 3-hydroxypropionaldehyde accumulation has not yet been elucidated. The rapid accumulation of 3- hydroxypropionaldehyde relying on the impeller tip speed shift was employed to investigate the influences of 3-hydroxypropionaldehyde to the activities of nine key enzymes related to glycerol metabolism, CO2 and O2 levels in off-gas, cell growth and 1,3-propanediol synthesis. Compared with that at 1.19 mmol/l 3-hydroxypropionaldehyde in broth, the residual enzymatic activities of the nine key enzymes ranged from 9.44 to 74.68% in the cultures at 7.5 mmol/l 3-hydroxypropionaldehyde in broth. The inhibitions of cell growth and the 1,3-propanediol synthesis were unnoticeable at the low level of 3- hydroxypropionaldehyde. By contrast, the CO2 and O2 levels changes in off-gas response to the 3- hydroxypropionaldehyde accumulation were less than 15 min. These results suggest that 3- hydroxypropionaldehyde inhibited the growth and metabolism of K. pneumoniae in a more complicated manner.Keywords: Fermentation, glycerol, 3-hydroxypropionaldehyde, Klebsiella pneumoniae, 1,3-propanediol

Smoking cessation and carotid atherosclerosis: The guangzhou biobank cohort studydCVD

Introduction Smoking has been shown to be associated with carotid atherosclerosis in cross-sectional and prospective studies in Western populations. However, few studies have examined the reversal of risk resulting from quitting smoking, and the results are conflicting. Methods 959 men aged 50e85 years were randomly selected from phase III (2006e2007) of the Guangzhou Biobank Cohort Study into this cross-sectional study. Common carotid artery intima-media thickness (CCAIMT) was measured by B-mode ultrasonography, and carotid artery plaques were identified. Major cardiovascular risk factors, including fasting triglyceride, low-density and high-density lipoprotein (LDL and HDL) cholesterol and glucose, and systolic and diastolic blood pressure, were assessed. Results CCA-IMT and the number of carotid plaque increased from never to former to current smokers (both p≤0.001). Among former smokers compared to current smokers, after adjustment for cigarette pack-years and other potential confounders, the adjusted ORs (95% CI) for quitting for 1-9, 10-19 and 20+ years were 0.77 (0.47 to 1.26), 0.45 (0.26 to 0.79) and 0.37 (0.17 to 0.77) for the presence of CCA atherosclerosis, and 0.69 (0.43 to 1.12), 0.47 (0.27 to 0.82) and 0.45 (0.23 to 0.96) for the presence of carotid plaques, respectively. Longer duration of quitting smoking was also significantly associated with decreasing risk of the severity of CCA atherosclerosis and carotid plaques (all p≤0.001). Conclusion Smoking cessation was beneficial in attenuating the risk of carotid atherosclerosis associated with cigarette smoking. The short duration of cessation in earlier studies is a likely explanation for the inconsistent results.published_or_final_versio

Inference of Allelopathy about Spartina Alterniflora to Scirpus Mariqueter by Effects of Activated Carbon on Soil

AbstractSpartina alterniflora Loisel is an invasive species in Jiuduansha Islands and threatens the survival of native species Scirpus mariqueter. In this study, activated carbon (AC) was applied to study the allelochemicals remained in the soil. Seed germination and seedling growth bioassays were used to test the allelopathic effect, and GC-MS was used to identify the allelochemicals. Our results showed: due to the invasion of S. alterniflora, germination of S. mariqueter seeds and the growth of seedlings were significantly inhibited. When AC was added into S. mariqueter soil, the germination had not been affected while the seedling growth was promoted significantly. When AC was added into the soil of S. alterniflora, both the germination and the seedling growth had an obvious improvement. All indicated that S. alterniflora soil contained allelochemicals which would be absorbed by AC. The identified allelochemicals were hexadecanoic acid, octadecanoic acid, dibutyl phthalate, (adipic acid, isohexyl methyl ester) and (adipic acid, di (oct-4-yl ester))

Measurement of the velocities in the transient acceleration process using all-fiber photonic Doppler velocimetry

Based on analysis of basic photonic Doppler velocimetry (PDV), a formula to measure velocity variation in a single cycle is put forward. PDV has been improved in three aspects, namely, the laser, the detector and the data processing. A measurement system for velocity of the initial stage of a shock motion has been demonstrated. Instantaneous velocity measurements have been performed. The experimental results have a good agreement with the values obtained from the accelerometer. Compared with the traditional fringe method, the proposed method in this paper can identify instantaneous velocity variation. So it is particularly suitable for measuring the velocity in the transient acceleration process of shock waves and detonation waves

Effect of alcohol and aldehyde dehydrogenase gene polymorphisms on alcohol-associated hypertension: the Guangzhou Biobank Cohort Study

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Ca isotope constraints on chemical weathering processes: Evidence from headwater in the Changjiang River, China

This study aims to clarify the relationship between chemical weathering of rocks and the carbon budget of rivers and better understand the weathering mechanisms of plateau watersheds. We chose to study the Jinsha River, which originates from the Tibetan Plateau and also is in the upper reaches of the Changjiang River. Analysis of hydrochemistry, radiogenic strontium isotope and stable calcium isotopes were conducted of the Jinsha River water samples, which were collected along its mainstream and main tributaries in the summer. The results show that the water chemistry of the mainstream waters is dominated by evaporite weathering, which have low 87Sr/86Sr values (0.7098–0.7108) and wide range of Sr contents (2.70–9.35 μmol/L). In contrast, tributaries of the Jinsha River have higher 87Sr/86Sr (0.7090–0.7157) and lower Sr contents (∼1 μmol/L). Moreover, the Ca isotopic compositions in the mainstream (0.87–1.11‰) are heavier than the tributaries (0.68–0.88‰) and could not be fully explained by the conventional mixing of different sources. We suggest that secondary carbonate precipitation fractionates Ca isotopes in the Jinsha River, and fractionation factors are between 0.99935 and 0.99963. At least 66% of Ca was removed in the mainstream of the Jinsha River through secondary mineral precipitation, and the average value is ∼35% in the tributaries. The results highlight that evaporite weathering results in more carbonate precipitation influencing Ca transportation and cycling in the riverine system constrained by stable Ca isotopic compositions and water chemistry

Depressive symptoms predict memory decline over subsequent 4 years: longitudinal analysis of the Guangzhou Biobank Cohort Study

Platform Presentations: Friday, Session 1 - Psychiatry and Mental HealthINTRODUCTION: Late-life depression may increase dementia risk, raising the possibility of overlapping pathophysiology and potential preventive strategies. We examined whether: a) baseline depressive symptoms predicted memory decline, and b) baseline memory function predicted mood decline, in an older Chinese cohort …published_or_final_versio

Fluorescence enhancement method for the determination of nucleic acids using cationic cyanine as a fluorescence probe

A fluorescence enhancement method with a cationic cyanine as a probe was developed for the determination of nucleic acids. Under the experimental conditions, the fluorescence enhancement of cyanine (lambda(ex)/lambda(em) = 524/591.5 nm) was observed in the presence of DNA. The calibration graphs were linear over the range of 0.01 - 15 mug mL(-1) for both calf thymus DNA (CT DNA) and fish sperm DNA (FS DNA). The limits of detection were 0.005 and 0.007 mug mL(-1) for CT DNA and FS DNA, respectively. The method was applied to the determination of DNA in synthetic and real samples and satisfactory results were obtained. A possible fluorescence enhancement mechanism was also studied