57 research outputs found
Gap Opening in Protoplanetary Disks: Gas Dynamics from Global Non-ideal MHD Simulations with Consistent Thermochemistry
Recent high angular resolution ALMA observations have revealed numerous gaps
in protoplanetary disks. A popular interpretation has been that planets open
them. Most previous investigations of planet gap-opening have concentrated on
viscous disks. Here, we carry out 2D (axisymmetric) global simulations of gap
opening by a planet in a wind-launching non-ideal MHD disk with consistent
thermochemistry. We find a strong concentration of poloidal magnetic flux in
the planet-opened gap, where the gas dynamics are magnetically dominated. The
magnetic field also drives a fast (nearly sonic) meridional gas circulation in
the denser disk regions near the inner and outer edges of the gap, which may be
observable through high-resolution molecular line observations. The gap is more
ionized than its denser surrounding regions, with a better magnetic
field-matter coupling. In particular, it has a much higher abundance of
molecular ion HCO, consistent with ALMA observations of the well-studied AS
209 protoplanetary disk that has prominent gaps and fast meridional motions
reaching the local sound speed. Finally, we provide fitting formulae for the
ambipolar and Ohmic diffusivities as a function of the disk local density,
which can be used for future 3D simulations of planet gap-opening in non-ideal
MHD disks where thermochemistry is too computationally expensive to evolve
self-consistently with the magneto-hydrodynamics.Comment: 12 pages, 13 figures and 4 tables, submitted to MNRAS. For animated
figures, see:
https://www.youtube.com/watch?v=GvVPT-SOP6s&list=PLPqbg5l-CV-t-TUePtpv7VtqPL1PHP1U5&ab_channel=FloridaKey
GW26-e3832 Rosuvastatin Improves Atherosclerotic Plaques Stability: An Intravascular Ultrasonic Elastography Study
Sequential Treatments with Tongsai and Bufei Yishen Granules Reduce Inflammation and Improve Pulmonary Function in Acute Exacerbation-Risk Window of Chronic Obstructive Pulmonary Disease in Rats
Background. Sequential treatments of Chinese medicines for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) risk window (RW) have benefits for preventing reoccurrences of AEs; however, the effects on pulmonary function, pulmonary, and systemic inflammatory biomarkers remain unclear. Methods. Cigarette-smoke/bacterial infections induced rats were randomized into Control, COPD, AECOPD, Tongsai Granule/normal saline (TSG/NS), moxifloxacin + salbutamol/NS (MXF+STL/NS), TSG/Bufei Yishen Granule (BYG), MXF+STL/STL, and TSG+MXF+STL/BYG+STL groups and given corresponding medicine(s) in AE- and/or RW phase. Body temperature, pulmonary function, blood cytology, serum amyloid A (SAA) and C-reactive protein (CRP), pulmonary histomorphology and myeloperoxidase (MPO), polymorphonuclear (PMN) elastase, interleukins IL-1β, IL-6, and IL-10, and tumor necrosis factor- (TNF-) α expressions were determined. Results. Body temperature, inflammatory cells and cytokines, SAA, CRP, and pulmonary impairment were higher in AECOPD rats than stable COPD, while pulmonary function declined and recovered to COPD level in 14–18 days. All biomarkers were improved in treated groups with shorter recovery times of 4–10 days, especially in TSG+MXF+STL/BYG+STL group. Conclusion. Sequential treatments with Tongsai and Bufei Yishen Granules, during AECOPD-RW periods, can reduce inflammatory response and improve pulmonary function and shorten the recovery courses of AEs, especially the integrated Chinese and Western medicines
Assessment of left ventricular function in patients with type 2 diabetes mellitus by non-invasive myocardial work
BackgroundDiabetes mellitus (DM) is a chronic disease that poses a serious risk of cardiovascular diseases. Therefore, early detection of impaired cardiac function with non-invasive myocardial imaging is critical for improving the prognosis of patients with DM.PurposeThis study aimed to assess the left ventricular (LV) function in patients with type 2 diabetes mellitus (T2DM) by non-invasive myocardial work technique.Materials and methodsIn all, 67 patients with T2DM and 28 healthy controls were included and divided into a DM group and a control group. Two-dimensional dynamic images of apical three-chamber view, apical two-chamber view, and apical four-chamber view were collected from all subjects, consisting of at least three cardiac cycles. LV myocardial strain parameters, including global longitudinal strain (GLS) and peak strain dispersion (PSD), as well as myocardial work parameters, including global constructive work (GCW), global wasted work (GWW), global work index (GWI), and global work efficiency (GWE), were obtained and analyzed.ResultsA total of 15 subjects were randomly selected to assess intra-observer and inter-observer consistency of myocardial work parameters and strain parameters, which showed excellent results (intra-class correlation coefficients: 0.856 - 0.983, P<0.001). Compared with the control group, the DM group showed significantly higher PSD (37.59 ± 17.18 ms vs. 27.72 ± 13.52 ms, P<0.05) and GWW (63.98 ± 43.63 mmHg% vs. 39.28 ± 25.67 mmHg%, P<0.05), and lower GWE (96.38 ± 2.02% vs. 97.72 ± 0.98%, P<0.001). Furthermore, the PSD was positively correlated with GWW (r = 0.565, P<0.001) and negatively correlated with GWE (r = -0.569, P<0.001).ConclusionUncoordinated LV myocardial strain, higher GWW, and lower GWE in patients with T2DM may serve as indicators for the early assessment of cardiac impairment in T2DM
Dust Condensation in Evolving Discs and the Composition of Planetary Building Blocks
Partial condensation of dust from the Solar nebula is likely responsible for the diverse chemical compositions of chondrites and rocky planets/planetesimals in the inner Solar system. We present a forward physical–chemical model of a protoplanetary disc to predict the chemical compositions of planetary building blocks that may form from such a disc. Our model includes the physical evolution of the disc and the condensation, partial advection, and decoupling of the dust within it. The chemical composition of the condensate changes with time and radius. We compare the results of two dust condensation models: one where an element condenses when the mid-plane temperature in the disc is lower than the 50 per cent condensation temperature (T50T50) of that element and the other where the condensation of the dust is calculated by a Gibbs free energy minimization technique assuming chemical equilibrium at local disc temperature and pressure. The results of two models are generally consistent with some systematic differences of ∼10 per cent depending upon the radial distance and an element’s condensation temperature. Both models predict compositions similar to CM, CO, and CV chondrites provided that the decoupling time-scale of the dust is of the order of the evolution time-scale of the disc or longer. If the decoupling time-scale is too short, the composition deviates significantly from the measured values. These models may contribute to our understanding of the chemical compositions of chondrites, and ultimately the terrestrial planets in the Solar system, and may constrain the potential chemical compositions of rocky exoplanets
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Waterways to Greenways: A Case Study in Shangjie, Zhengzhou, Henan, China
This case study introduces how we used a water sensitive approach to plan a storm water and sponge city project, which expanded into a holistic green infrastructure project. The project is in the Shangjie district in city of Zhengzhou, Henan China. The whole site is 61.16 km² including several waterways. The city is expanding into areas that were previously agricultural. Developers and city both desire to improve the ecological value of the city to boost the economic growth of the Shangjie district.
The main goal for the client is to transform the existing industrial city into a more resilient and livable ecological region. Our approach is to holistically solve the region\u27s increasing demand for flood control and storm water management, and to improve ecological and recreational values along these riparian corridors. We propose additional waterways and water bodies to act as green infrastructure, then link the greenways to existing or proposed parks to form a comprehensive greenway network.
Our multidisciplinary team conducted detailed investigations and collaborated extensively. The team consists of hydraulic engineers, civil engineers, environmental planners, landscape planners, urban planners, economic planners, and others. We used a variety of technologies, including GIS, Infoworks, remote sensing technology, MIKE model, and lab tests
Direct Conversion of Mouse Astrocytes Into Neural Progenitor Cells and Specific Lineages of Neurons
Background: Cell replacement therapy has been envisioned as a promising treatment for neurodegenerative diseases. Due to the ethical concerns of ESCs-derived neural progenitor cells (NPCs) and tumorigenic potential of iPSCs, reprogramming of somatic cells directly into multipotent NPCs has emerged as a preferred approach for cell transplantation.
Methods: Mouse astrocytes were reprogrammed into NPCs by the overexpression of transcription factors (TFs) Foxg1, Sox2, and Brn2. The generation of subtypes of neurons was directed by the force expression of cell-type specific TFs Lhx8 or Foxa2/Lmx1a.
Results: Astrocyte-derived induced NPCs (AiNPCs) share high similarities, including the expression of NPC-specific genes, DNA methylation patterns, the ability to proliferate and differentiate, with the wild type NPCs. The AiNPCs are committed to the forebrain identity and predominantly differentiated into glutamatergic and GABAergic neuronal subtypes. Interestingly, additional overexpression of TFs Lhx8 and Foxa2/Lmx1a in AiNPCs promoted cholinergic and dopaminergic neuronal differentiation, respectively.
Conclusions: Our studies suggest that astrocytes can be converted into AiNPCs and lineage-committed AiNPCs can acquire differentiation potential of other lineages through forced expression of specific TFs. Understanding the impact of the TF sets on the reprogramming and differentiation into specific lineages of neurons will provide valuable strategies for astrocyte-based cell therapy in neurodegenerative diseases
A mcr-1-Carrying Conjugative IncX4 Plasmid in Colistin-Resistant Escherichia coli ST278 Strain Isolated From Dairy Cow Feces in Shanghai, China
Enterobacteriaceae, including Escherichia coli, has been shown to acquire the colistin resistance gene mcr-1. A strain of E. coli, EC11, which is resistant to colistin, polymyxin B and trimethoprim-sulfamethoxazole, was isolated in 2016 from the feces of a dairy cow in Shanghai, China. Strain EC11 identifies with sequence type ST278 and is susceptible to 19 frequently used antibiotics. Whole genome sequencing of strain EC11 showed that this strain contains a 31-kb resistance plasmid, pEC11b, which belongs to the IncX4 group. The mcr-1 gene was shown to be inserted into a 2.6-kb mcr-1-pap2 cassette of pEC11b. Plasmid pEC11b also contained putative conjugal transfer components, including an oriT-like region, relaxase, type IV coupling protein, and type IV secretion system. We were successful in transferring pEC11b to E. coli C600 with an average transconjugation efficiency of 4.6 × 10-5. Additionally, a MLST-based analysis comparing EC11 and other reported mcr-positive E. coli populations showed high genotypic diversity. The discovery of the E. coli strain EC11 with resistance to colistin in Shanghai emphasizes the importance of vigilance in detecting new threats like mcr genes to public health. Detection of mcr genes helps in tracking, slowing, and responding to the emergence of antibiotic resistance in Chinese livestock farming
A Comprehensive Research on Antibiotic Resistance Genes in Microbiota of Aquatic Animals
The occurrence of antibiotic resistance genes (ARGs) as emerging contaminants is of continued concern for human health. Antibiotics used in aquaculture have promoted the evolution and spread of ARGs. This study aimed to investigate the occurrence of 37 ARGs conferring resistance to six classes of antibiotics in 94 aquatic animals from five cities in southeast coast of China. The results showed that floR, sulII, sulI, strB, strA, aadA, and tetS were identified as the prominent ARGs with the high detection frequencies ranging from 30.9 to 51.1% in total samples. Then relative expression amount of seven prominent ARGs quantified by qPCR, ranging from 0.003 to 0.065. The tetS was the most abundant ARG among the seven ARGs. Though aadA was the second highest detection frequency of ARGs, it was the lowest expression amount ARG. The occurrences and abundances of ARGs in freshwater aquatic animals were greater than those in marine, reflecting the discrepancy of cultivation pattern between the freshwater and marine aquaculture. Shanghai was considered as the most prevalent site with 16 ARGs, and Ningbo merely contained 9 ARGs without of β-lactam ARGs and quinolone ARGs, showing variations of ARGs with geographical location. Eight kinds of sulfonamides and one chloramphenicol residues were further measured in samples from Shanghai. Interestingly, no target antibiotics were found, but sulfonamides resistance genes (sulI, sulII) and chloramphenicol resistance genes (floR) persisted at aquatic animals in the absence of selection pressure. Our research firstly shows comprehensive information on the ARGs in skin microbiota of aquatic animals, which could provide useful information and a new insight for better understanding on the ARGs dissemination in aquatic animals
A Comprehensive Epidemiological Research for Clinical Vibrio parahaemolyticus in Shanghai
Vibrio parahaemolyticus is one of the most important pathogen for seafood-borne gastroenteritis in Shanghai and the rest of the world. A total of 42 V. parahaemolyticus strains were isolated from 1900 fecal specimens collected from patients in Shanghai hospital presenting from January 2014 to December 2015. All isolates were evaluated for potential virulence factors [tdh, trh, and type three secretion system (T3SS) genes], typed using multilocus sequence typing (MLST) and screened for antimicrobial resistance phenotype and genotype. And for the first time, the relationship between virulence, genetic diversity and antimicrobial resistance of these isolates were identified. The results showed that 37 isolates carried the tdh gene (88.1%) and only seven isolates were positive for the trh gene. The T3SS1 and T3SS2 genes were detected in all strains and only trh-positive isolates are also containing the T3SS2β genes. MLST analysis of the 42 Shanghai isolates identified 20 sequence types (STs) with 16 novel STs and that these clinical V. parahaemolyticus strains showed high degrees of genetic diversity. All isolates expressed high levels of resistance against Ampicillin (100.0%), Streptomycin (100.0%), Cephazolin (92.9%), Kanamycin (92.8%) and Amikacin (90.5%), and eight out of 38 resistance genes (SHV, tet(B), strA, qnrA, gryA, qnrB, sulI, sulII) were detected in at least two isolates. This study confirms that antimicrobial resistance of clinical V. parahaemolyticus isolates is greater than those of environmental isolates. Furthermore, no clear correlation between antimicrobial resistance and virulence or genetic diversity was found in this study. These results add to epidemiological data of clinical V. parahaemolyticus isolates in Shanghai and highlight the need for additional mechanistic studies, especially antimicrobial resistance, to reduce the burden of disease caused by this pathogen in China
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