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The essence of the maximum drag reduction (MDR) state of viscoelastic drag-reducing turbulence (DRT) is still under debate, which mainly holds two different types of views: the marginal state of inertial turbulence (IT) and elasto-inertial turbulence (EIT). To further promote its understanding, this paper conducts a large number of direct numerical simulations of DRT at a modest Reynolds number Re with $Re = 6000$ for the FENE-P model that covers a wide range of flow states and focuses on the problem of how nonlinear extension affects the nature of MDR by varying the maximum extension length $L$ of polymers. It demonstrates that the essence of the MDR state can be both IT and EIT, where $L$ is somehow an important parameter in determining the dominant dynamics. Moreover, there exists a critical $L_c$ under which the minimum flow drag can be achieved in the MDR state even exceeding the suggested MDR limit. Systematic analyses on the statistical properties, energy spectrum, characteristic structures and underly dynamics show that the dominant dynamics of the MDR state gradually shift from IT-related to EIT-related dynamics with an increase of $L$. The above effects can be explained by the effective elasticity introduced by different $L$ at a fixed Weissenberg number (Wi) as well as the excitation of pure EIT. It indicates that larger $L$ introduces more effective elasticity and is favourable to EIT excitation. Therefore, we argue that the MDR state is still dominated by IT-related dynamics for the case of small $L$, but replaced by EIT-related dynamics at high $L$. The obtained results can harmonize the seemingly controversial viewpoints on the dominant dynamics of the MDR state and also provide some ideas for breaking through the MDR limit, such as searching for a polymer solution with a proper molecular length and concentration.
In recent years, bat-associated pathogens, such as 2019 novel coronavirus, have been ravaging the world, and ectoparasites of bats have received increasing attention. Penicillidia jenynsii is a member of the family Nycteribiidae which is a group of specialized ectoparasites of bats. In this study, the complete mitochondrial genome of P. jenynsii was sequenced for the first time and a comprehensive phylogenetic analysis of the superfamily Hippoboscoidea was conducted. The complete mitochondrial genome of P. jenynsii is 16 165 base pairs (bp) in size, including 13 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes and 1 control region. The phylogenetic analysis based on 13 PCGs of the superfamily Hippoboscoidea known from the NCBI supported the monophyly of the family Nycteribiidae, and the family Nycteribiidae was a sister group with the family Streblidae. This study not only provided molecular data for the identification of P. jenynsii, but also provided a reference for the phylogenetic analysis of the superfamily Hippoboscoidea.
ABSTRACT IMPACT: This study has implications for understanding early developmental mechanisms of ADHD and for guidelines regarding safe use of acetaminophen during pregnancy. OBJECTIVES/GOALS: Prenatal acetaminophen exposure has been associated with childhood attention-deficit hyperactivity disorder (ADHD), but the underlying mechanism is unknown. This prospective birth cohort study aims to identify linkages between specific metabolites in umbilical cord plasma and the association of prenatal acetaminophen exposure and ADHD. METHODS/STUDY POPULATION: The sample was a subset of the Boston Birth Cohort that included 583 mother-newborn dyads followed at Boston Medical Center from 1998 to 2018. Metabolites were measured from cord plasma collected at birth. Based on existing literature, the analyses focused on candidate metabolites involved in neuroendocrine, inflammation, and oxidative stress pathways. The outcome was physician-diagnosed ADHD between the ages of 3 and 16 years. Exploratory analyses and multiple logistic regressions were used to examine the association of these candidate metabolites with both unmetabolized cord plasma acetaminophen levels and with incident risk of ADHD, adjusting for covariates of maternal and child characteristics. RESULTS/ANTICIPATED RESULTS: Of the 583 children, 257 had ADHD and 326 had neurotypical development. Two promising results have been found thus far. 5-methoxytryptophol (5-MTX), a neuroendocrine molecule which also has antioxidant and immunomodulatory properties, was inversely associated with acetaminophen and ADHD risk. For children below the median cord 5-MTX level, the odds of ADHD were 3.29 (95% CI [1.56, 7.16], p=0.002) for the third tertile of acetaminophen compared to the first tertile. This association attenuated among those above the median 5-MTX level: 2.23 (95% CI [0.98, 5.21], p=0.059), suggesting a protective effect. Tryptophan, an essential amino acid and precursor of serotonin, was positively associated with acetaminophen and ADHD. Next steps include mediation analysis with tryptophan and analyses for other metabolites. DISCUSSION/SIGNIFICANCE OF FINDINGS: This study identifies cord plasma metabolites as possible modifiers or mediators linking prenatal acetaminophen exposure and childhood ADHD, which may offer insight into a mechanistic pathway. The study findings have implications for FDA, clinical, and public health guidelines regarding safe use of acetaminophen during pregnancy.
We aimed to examine whether baseline neutrophil counts affected the risk of new-onset proteinuria in hypertensive patients, and, if so, whether folic acid treatment is particularly effective in proteinuria prevention in such a setting. A total of 8208 eligible participants without proteinuria at baseline were analysed from the renal substudy of the China Stroke Primary Prevention Trial. Participants were randomised to receive a double-blind daily treatment of 10 mg of enalapril and 0·8 mg of folic acid (n 4101) or 10 mg of enalapril only (n 4107). The primary outcome was new-onset proteinuria, defined as a urine dipstick reading of ≥1+ at the exit visit. The mean age of the participants was 59·5 (sd, 7·4) years, 3088 (37·6 %) of the participants were male. The median treatment duration was 4·4 years. In the enalapril-only group, a significantly higher risk of new-onset proteinuria was found among participants with higher neutrophil counts (quintile 5; ≥4·8 × 109/l, OR 1·44; 95 % CI 1·00, 2·06), compared with those in quintiles 1–4. For those with enalapril and folic acid treatment, compared with the enalapril-only group, the new-onset proteinuria risk was reduced from 5·2 to 2·8 % (OR 0·49; 95 % CI 0·29, 0·82) among participants with higher neutrophil counts (≥4·8 × 109/l), whereas there was no significant effect among those with neutrophil counts <4·8 × 109/l. In summary, among hypertensive patients, those with higher neutrophil counts had increased risk of new-onset proteinuria, and this risk was reduced by 51 % with folic acid treatment.
OBJECTIVES/GOALS: It is hypothesized that the global secular trend toward earlier puberty onset, with implications for many future health outcomes, is related to the obesity epidemic. This study aims to examine prospective associations between weight during specific developmental windows and timing of puberty onset. METHODS/STUDY POPULATION: This study includes 1,296 mother-infant dyads from the Boston Birth Cohort, a predominantly minority (>80% black/Hispanic), low-income, and urban prospective birth cohort recruited and followed between 1998 and 2019. Age at peak height velocity (APHV), a well-defined and standardized proxy for puberty onset, is derived by fitting height measurements recorded during clinical visits using a mixed effects growth curve model. Multiple linear regression is performed to examine the relationships between early childhood (ages 2-5y) and prepubertal (ages 6-9y) overweight and obesity, weight trajectories between these two periods, and APHV, while controlling for known contributors to early puberty. RESULTS/ANTICIPATED RESULTS: Compared to counterparts with normal BMIs, kids who were obese during ages 2-5y (boys: −0.21y, CI[−0.39, −0.04]; girls: −0.22y, CI[−0.39, −0.05]) or ages 6-9y (boys: −0.27y, CI[−0.43, −0.11]; girls: −0.37y, CI[−0.52, −0.23]) had an earlier APHV. Being overweight during ages 6-9y was also associated an earlier APHV (boys: −0.26y, CI[−0.46, −0.07]; girls: −0.26y, CI[−0.42, −0.10]). Looking at weight trajectories, kids who were persistently overweight or obese from ages 2-5y to ages 6-9y had an earlier APHV (boys: −0.28y, CI[−0.45, −0.12]; girls: −0.31y, CI[−0.46, −0.16]), as did girls with normal BMIs during ages 2-5y and who were overweight or obese during ages 6-9y (−0.45y CI[−0.64, −0.26]). DISCUSSION/SIGNIFICANCE OF IMPACT: The temporal and dose-response relationships seen in this historically understudied population suggests that childhood obesity is etiologically important in the development, and even programming, of early puberty. This has implications for prediction, prevention, and mitigation of health disparities.
We aimed to evaluate the relationship of plasma Mg with the risk of new-onset hyperuricaemia and examine any possible effect modifiers in hypertensive patients. This is a post hoc analysis of the Uric acid (UA) Sub-study of the China Stroke Primary Prevention Trial (CSPPT). A total of 1685 participants were included in the present study. The main outcome was new-onset hyperuricaemia defined as a UA concentration ≥417 μmol/l in men or ≥357 μmol/l in women. The secondary outcome was a change in UA concentration defined as UA at the exit visit minus that at baseline. During a median follow-up duration of 4·3 years, new-onset hyperuricaemia occurred in 290 (17·2 %) participants. There was a significantly inverse relation of plasma Mg with the risk of new-onset hyperuricaemia (per sd increment; OR 0·85; 95 % CI 0·74, 0·99) and change in UA levels (per sd increment; β −3·96 μmol/l; 95 % CI −7·14, −0·79). Consistently, when plasma Mg was analysed as tertiles, a significantly lower risk of new-onset hyperuricaemia (OR 0·67; 95 % CI 0·48, 0·95) and less increase in UA levels (β −8·35 μmol/l; 95 % CI −16·12, −0·58) were found among participants in tertile 3 (≥885·5 μmol/l) compared with those in tertile 1 (<818·9 μmol/l). Similar trends were found in males and females. Higher plasma Mg levels were associated with a decreased risk of new-onset hyperuricaemia in hypertensive adults.
We aimed to investigate the association between plasma retinol and incident cancer among Chinese hypertensive adults. We conducted a nested case–control study, including 231 patients with incident cancer and 231 matched controls during a median 4·5-year follow-up of the China Stroke Primary Prevention Trial. There was a significant, inverse association between retinol levels and digestive system cancer (per 10 μg/dl increases: OR 0·79; 95 % CI 0·69, 0·91). When compared with participants in the first quartile of retinol (< 52·3 μg/dl), a significantly lower cancer risk was found in participants in quartile 2–4 ( ≥ 52·3 μg/dl: OR 0·31; 95 % CI 0·13, 0·71). However, there was a U-shaped association between retinol levels and non-digestive system cancers where the risk of cancers decreased (although not significantly) with each increment of plasma retinol (per 10 μg/dl increases: OR 0·89; 95 % CI 0·60, 1·31) in participants with retinol < 68·2 μg/dl, and then increased significantly with retinol (per 10 μg/dl increase: OR 1·65; 95 % CI 1·12, 2·44) in participants with retinol ≥ 68·2 μg/dl. In conclusion, there was a significant inverse dose–response association between plasma retinol and the risk of digestive system cancers. However, a U-shaped association was observed between plasma retinol and the risk of non-digestive cancers (with a turning point approximately 68·2 μg/dl).
While maternal folate deficiency has been linked to poor pregnancy outcomes such as neural tube defects, anaemia and low birth weight, the relationship between folate and preterm birth (PTB) in the context of the US post-folic acid fortification era is inconclusive. We sought to explore the relationship between maternal folate status and PTB and its subtypes, i.e. spontaneous and medically indicated PTB.
Boston Birth Cohort, a predominantly urban, low-income, race/ethnic minority population at a high risk for PTB.
Mother–infant dyads (n 7675) enrolled in the Boston Birth Cohort. A sub-sample (n 2313) of these dyads had maternal plasma folate samples collected 24–72 h after delivery.
Unadjusted and adjusted logistic regressions revealed an inverse relationship between the frequency of multivitamin supplement intake and PTB. Compared with less frequent use, multivitamin supplement intake 3–5 times/week (adjusted OR (aOR) = 0·78; 95 % CI 0·64, 0·96) or >5 times/week (aOR = 0·77; 95 % CI 0·64, 0·93) throughout pregnancy was associated with reduced risk of PTB. Consistently, higher plasma folate levels (highest v. lowest quartile) were associated with lower risk of PTB (aOR = 0·74; 95 % CI 0·56, 0·97). The above associations were similar among spontaneous and medically indicated PTB.
If confirmed by future studies, our findings raise the possibility that optimizing maternal folate levels across pregnancy may help to reduce the risk of PTB among the most vulnerable US population in the post-folic acid fortification era.
Studies for spin parameters and shapes of asteroids provide us with important information about the interior structure of asteroids and the physical processes they have undergone. A large sample of basic physical parameters can help us also understand the evolution of asteroids. There is scarce information for slowly-rotating larger asteroids because more effort is required for observing them. Because of this, we have established an international collaboration to study slowly-rotating asteroids. As the first step of this project, we have observed asteroids (168) Sibylla and (346) Hermentaria in 2014 and 2015 using several telescopes located in China, Chile, and U.S.A. Combining previous photometric data with our new data, we have performed preliminary analyses and obtained spin parameters and shapes with their uncertainties for these two slowly-rotating asteroids for the first time, using the convex inversion method and the virtual photometry Monte Carlo method. A pair of pole solutions for (168) Sibylla are found around (4.3°, 53.5°) and (183.5°, 52.6°) with a period of 47.0000 h. We have found that the shape of Sibylla resembles an oblate spheroid. For (346) Hermentaria, we have also found a pair of pole solutions around (134.5°, 16.7°) and (321.5°, 14.5°) with comparable rms-values with a spin period of about 17.79000 h, and a shape resembling a prolate spheroid.
SONG (Stellar Observations Network Goup) is a low-cost ground based international collaboration aimed at two cutting edge problems in contemporary astrophysics in the time-domain: 1) Direct diagnostics of the internal structure of stars and 2) looking for and studying extra solar planets, possibly in the habitable zone. The general plan is to set up a network of 1m telescopes uniformly distributed in geographic latitude (in both hemispheres). China jointed the collaboration (initiated by Danish astronomers) at the very beginning. In addition to SONG's original plan (http://song.phys.au.dk), the Chinese team proposed a parallel photometry subnet work in the northern hemisphere, namely 50BiN (50cm Binocular Network, previously known as mini-SONG), to enable a large field photometric capability for the network, therefore maximising the potential of the network platform. The network will be able to produce nearly continuous time series observations of a number of selected objects with high resolution spectroscopy (SONG) and accurate photometry (50BiN), and to produce ultra-high accuracy photometry in dense field to look for micro-lensing events caused by planetary systems. This project has great synergy with Chinese Astronomical activities in Antarctica (Dome A), and other similar networks (e.g. LCOGT). The plan and current status of the project are overviewed in this poster.
Although ascarid nematodes are important parasites of wild animals of public health concern, few species of ascarids from wild animals have been studied at the molecular level so far. Here, the classification and phylogenetic relationships of roundworms from 21 species of captive wild animals have been studied by sequencing and analysis of parts of the ribosomal 18S and 28S genes and the mitochondrial (mt) 12S gene. Phylogenetic relationships were inferred by 3 methods (NJ/MP/ML) based on the data of single gene sequences and concatenated sequences. Homology analysis indicated that the 18S sequences were conserved among roundworms from all 21 species and that 28S showed interspecies variability. Divergence levels displayed in 12S suggested that 12S appears to be either intra- or interspecifically variable. Evolutionary trees indicated that the ascarids split into 2 families, 4 genera and 7 species, with high bootstrap support for each clade. Combined trees suggested that Baylisascaris ailuri is more closely related to B. transfuga than to B. schroederi. This study provides useful molecular markers for the classification, phylogenetic analysis and epidemiological investigation of roundworms from wild animals.
The characteristic of the over-volted breakdown and the gaseous recovery in short nitrogen gaps was experimentally studied. It was found that the breakdown voltage of the gap changes from shot to shot even with the same experimental conditions and obeys Gaussian distribution. The over-volted factor is reduced with an increasing pressure. With a 2.7-mm gap the over-volted factors are 4.53 for 0.1 MPa pressure and 1.74 for 0.4 MPa. The over-volted breakdown voltage depends individually on the gap spacing d and the gas pressure p, rather than on the product of pd. An empirical formula of the breakdown voltage as a function of p and d was derived. The time-dependent recovery of the breakdown voltage, RVb, was obtained using a two-pulse technique. The second breakdown voltage also obeys Gaussian distribution, but it is normally with a smaller standard deviation especially when the interpulse spacing of Δt is relatively short. As a whole, RVb rises with the increase of Δt. However, an intermediate plateau is always observed and it starts when the second breakdown voltage is a little bit higher than the static breakdown voltage of the gap. The first rising edge of the RVb curve corresponds to the recovery of the electro-neutrality and the density. The intermediate plateau and the following rising edge take the spark gap much longer time to recover. The processes governing these two latter phases are as yet not fully clear. It is attributed to the delayed recombination of the residual nitrogen atoms on the cathode to produce the initial electrons for the second breakdown. An increase in pressure has resulted in an upward shift of the intermediate plateau and a shortening in the recovery time of the gaps. The second spark generally does not follow the path of the first spark.
The electrochemical capacity, hydrogen absorbed/desorbed activation properties of alloy Zr(Mn0.1V0.3Ni0.6)2 were improved after Ti substitution for the Zr. The microstructure of Zr1xTix (Mn0.1V0.3Ni0.6)2 (x = 0, 0.5) alloys was analyzed by x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive spectrum (EDS) analysis. A systematic structural analysis shows that there are two phases in the Ti-substituted alloy of Zr0.5Ti0.5(Mn0.1V0.3Ni0.6)2: C14 Laves phase and Ti-containing “premartensite” R phase of Ti0.8Zr0.2Ni. The improvement of electrochemical properties of alloy Zr(Mn0.1V0.3Ni0.6)2 after Ti substitution can be attributed to the Ti substitution for Zr sites in C14 Laves phase, the formation of Ti0.8Zr0.2Ni R-phase, and disappearance of Zr–Ni binaries.
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