Star-factors of tournaments

Let S_m denote the m-vertex simple digraph formed by m-1 edges with a common tail. Let f(m) denote the minimum n such that every n-vertex tournament has a spanning subgraph consisting of n/m disjoint copies of S_m. We prove that m lg m - m lg lg m <= f(m) <= 4m^2 - 6m for sufficiently large m.Comment: 5 pages, 1 figur

Adsorption and desorption of methylene blue on porous carbon monoliths and nanocrystalline cellulose

The dynamic batch adsorption of methylene blue (MB), a widely used and toxic dye, onto nanocrystalline cellulose (NCC) and crushed powder of carbon monolith (CM) was investigated using the pseudo-first- and -second-order kinetics. CM outperformed NCC with a maximum capacity of 127 mg/g compared to 101 mg/g for NCC. The Langmuir isotherm model was applicable for describing the binding data for MB on CM and NCC, indicating the homogeneous surface of these two materials. The Gibbs free energy of −15.22 kJ/mol estimated for CM unravelled the spontaneous nature of this adsorbent for MB, appreciably faster than the use of NCC (−4.47 kJ/mol). Both pH and temperature exhibited only a modest effect on the adsorption of MB onto CM. The desorption of MB from CM using acetonitrile was very effective with more than 94 % of MB desorbed from CM within 10 min to allow the reusability of this porous carbon material. In contrast, acetonitrile was less effective than ethanol in desorbing MB from NCC. The two solvents were incapable of completely desorbing MB on commercial granular coal-derived activated carbon

Site-1 protease is essential for endochondral bone formation in mice

Site-1 protease (S1P) has an essential function in the conversion of latent, membrane-bound transcription factors to their free, active form. In mammals, abundant expression of S1P in chondrocytes suggests an involvement in chondrocyte function. To determine the requirement of S1P in cartilage and bone development, we have created cartilage-specific S1P knockout mice (S1Pcko). S1Pcko mice exhibit chondrodysplasia and a complete lack of endochondral ossification even though Runx2 expression, Indian hedgehog signaling, and osteoblastogenesis is intact. However, there is a substantial increase in chondrocyte apoptosis in the cartilage of S1Pcko mice. Extraction of type II collagen is substantially lower from S1Pcko cartilage. In S1Pcko mice, the collagen network is disorganized and collagen becomes entrapped in chondrocytes. Ultrastructural analysis reveals that the endoplasmic reticulum (ER) in S1Pcko chondrocytes is engorged and fragmented in a manner characteristic of severe ER stress. These data suggest that S1P activity is necessary for a specialized ER stress response required by chondrocytes for the genesis of normal cartilage and thus endochondral ossification

Scenarios study on post-consumer plastic packaging waste recycling

We all use plastics on a daily basis. Plastics come in many shapes, sizes and compositions and are used in a wide variety of products. Almost all of the currently used plastic packaging are made from fossil resources, which are finite. The production of plastic packages causes environmental impacts, whereas the correct use of these packages will reduce product losses and hence reduce the much more negative environmental impacts associated with product losses. Wrongly discarded plastic objects have a negative impact on the environment, as these materials degrade only very slowly, creating problems such as the infamous ‘plastic islands’ in our oceans. Fortunately, recycling technologies are now emerging for plastic waste, enabling the reuse of these materials in a second life as a package or a utensil. Plastic packaging waste (PPW) is complex in many ways. First of all, there are many different types of plastics, all with their own characteristics and compositions. To enable the re-use of PPW, it has to be sorted into separate fractions. Each type of plastic can then be dealt with in an appropriate way. Second, the collection of PPW is also very complex. In the Netherlands there are many different PPW flows, from industry, offices and households for example. Each has its own collection system and household collection systems differ from one municipality to the next. To add to this complexity there is also the deposit refund system for large PET bottles, run by the soda producers via the supermarkets. Everybody deals with PPW on a daily basis. Most of us think recycling is a good idea. But when we want to decide what the best and most efficient method of recycling is, we are all impaired by a lack of data. A clear view of our best options is inhibited by the existing infrastructure and ‘the way it has always been done’. Also, the subject of recycling touches on our moral opinions about ‘doing the right thing’ and assumptions about the ‘correct’ way of dealing with our plastic waste. And politics also play a role. To unravel the complexity of plastic packaging waste recycling and figure out the best way(s) to improve our recycling system we need science. We need technological, economical, logistical and environmental data to gain insight into recycling systems. By describing the system in detail we can learn how to optimise it. An improved recycling system will provide us with an easier and more efficient re-use of our plastic waste

Exposure to Bisphenol A and Other Phenols in Neonatal Intensive Care Unit Premature Infants

Objective: We previously demonstrated that exposure to polyvinyl chloride plastic medical devices containing di(2-ethylhexyl) phthalate (DEHP) was associated with higher urinary concentrations of several DEHP metabolites in 54 premature infants in two neonatal intensive care units than in the general population. For 42 of these infants, we evaluated urinary concentrations of several phenols, including bisphenol A (BPA), in association with the use of the same medical devices. Measurements: We measured the urinary concentrations of free and total (free plus conjugated) species of BPA, triclosan, benzophenone-3, methyl paraben, and propyl paraben. Results: The percentage of BPA present as its conjugated species was > 90% in more than three-quarters of the premature infants. Intensity of use of products containing DEHP was strongly associated with BPA total concentrations but not with any other phenol. Adjusting for institution and sex, BPA total concentrations among infants in the group of high use of DEHP-containing products were 8.75 times as high as among infants in the low use group (p < 0.0001). Similarly, after adjusting for sex and DEHP-containing product use category, BPA total concentrations among infants in Institution A were 16.6 times as high as those among infants in Institution B (p < 0.0001). Conclusion: BPA geometric mean urinary concentration (30.3 μg/L) among premature infants undergoing intensive therapeutic medical interventions was one order of magnitude higher than that among the general population. Conjugated species were the primary urinary metabolites of BPA, suggesting that premature infants have some capacity to metabolize BPA. The differences in exposure to BPA by intensity of use of DEHP-containing medical products highlight the need for further studies to determine the specific source(s) of exposure to BPA

A strawberry accession with elevated methyl anthranilate fruit concentration is naturally resistant to the pest fly Drosophila suzukii

During the past decade, Drosophila suzukii has established itself as a global invasive fruit pest, enabled by its ability to lay eggs into fresh, ripening fruit. In a previous study, we investigated the impact of different strawberry accessions on the development of D. suzukii eggs, in the search of natural resistance. We identified several accessions that significantly reduced adult fly emergence from infested fruit. In the present study, we aimed at understanding the chemical basis of this effect. We first noted that one of the more resistant accessions showed an unusual enrichment of methyl anthranilate within its fruit, prompting us to investigate this fruit compound as a possible cause limiting fly development. We found that methyl anthranilate alone triggers embryo lethality in a concentration-dependent manner, unlike another comparable organic fruit compound. We also showed that a chemical fraction of the resistant strawberry accession that contains methyl anthranilate carries some activity toward the egg hatching rate. Surprisingly, in spite of the lethal effect of this compound to their eggs, adult females are not only attracted to methyl anthranilate at certain concentrations, but they also display a concentration-dependent preference to lay on substrates enriched in methyl anthranilate. This study demonstrates that methyl anthranilate is a potent agonist molecule against D. suzukii egg development. Its elevated concentration in a specific strawberry accession proven to reduce the fly development may explain, at least in part the fruit resistance. It further illustrates how a single, natural compound, non-toxic to humans could be exploited for biological control of a pest species

Urinary Bisphenol A Concentrations and Implantation Failure among Women Undergoing in Vitro Fertilization

Background: Bisphenol A (BPA) is a synthetic chemical widely used in the production of polycarbonate plastic and epoxy resins found in numerous consumer products. In experimental animals, BPA increases embryo implantation failure and reduces litter size. Objective: We evaluated the association of urinary BPA concentrations with implantation failure among women undergoing in vitro fertilization (IVF). Methods: We used online solid phase extraction–high performance liquid chromatography–isotope dilution tandem mass spectrometry to measure urinary BPA concentrations in 137 women in a prospective cohort study among women undergoing IVF at the Massachusetts General Hospital Fertility Center in Boston, Massachusetts. We used logistic regression to evaluate the association of cycle-specific urinary BPA concentrations with implantation failure, accounting for correlation among multiple IVF cycles in the same woman using generalized estimating equations. Implantation failure was defined as a negative serum β-human chorionic gonadotropin test (β-hCG < 6 IU/L) 17 days after egg retrieval. Results: Among 137 women undergoing 180 IVF cycles, urinary BPA concentrations had a geometric mean (SD) of 1.53 (2.22) µg/L. Overall, 42% (n = 75) of the IVF cycles resulted in implantation failure. In adjusted models, there was an increased odds of implantation failure with higher quartiles of urinary BPA concentrations {odds ratio (OR) 1.02 [95% confidence interval (CI): 0.35, 2.95}, 1.60 (95% CI: 0.70, 3.78), and 2.11 (95% CI: 0.84, 5.31) for quartiles 2, 3, and 4, respectively, compared with the lowest quartile (p-trend = 0.06). Conclusion: There was a positive linear dose–response association between BPA urinary concentrations and implantation failure

Prenatal Bisphenol A Exposure and Early Childhood Behavior

BackgroundPrenatal exposure to bisphenol A (BPA) increases offspring aggression and diminishes differences in sexually dimorphic behaviors in rodents.ObjectiveWe examined the association between prenatal BPA exposure and behavior in 2-year-old children.MethodsWe used data from 249 mothers and their children in Cincinnati, Ohio (USA). Maternal urine was collected around 16 and 26 weeks of gestation and at birth. BPA concentrations were quantified using high-performance liquid chromatography–isotope-dilution tandem mass spectrometry. Child behavior was assessed at 2 years of age using the second edition of the Behavioral Assessment System for Children (BASC-2). The association between prenatal BPA concentrations and BASC-2 scores was analyzed using linear regression.ResultsMedian BPA concentrations were 1.8 (16 weeks), 1.7 (26 weeks), and 1.3 (birth) ng/mL. Mean (± SD) BASC-2 externalizing and internalizing scores were 47.6 ± 7.8 and 44.8 ± 7.0, respectively. After adjustment for confounders, log10-transformed mean prenatal BPA concentrations were associated with externalizing scores, but only among females [β = 6.0; 95% confidence interval (CI), 0.1–12.0]. Compared with 26-week and birth concentrations, BPA concentrations collected around 16 weeks were more strongly associated with externalizing scores among all children (β = 2.9; 95% CI, 0.2–5.7), and this association was stronger in females than in males. Among all children, measurements collected at ≤ 16 weeks showed a stronger association (β = 5.1; 95% CI, 1.5–8.6) with externalizing scores than did measurements taken at 17–21 weeks (β = 0.6; 95% CI, −2.9 to 4.1).ConclusionsThese results suggest that prenatal BPA exposure may be associated with externalizing behaviors in 2-year-old children, especially among female children

Evaluation of next generation sequencing platforms for population targeted sequencing studies

Human sequence generated from three next-generation sequencing platforms reveals systematic variability in sequence coverage due to local sequence characteristics