131 research outputs found
Evolutionary Stages and Disk Properties of Young Stellar Objects in the Perseus Cloud
We investigated the evolutionary stages and disk properties of 211 Young
stellar objects (YSOs) across the Perseus cloud by modeling the broadband
optical to mid-infrared (IR) spectral energy distribution (SED). By exploring
the relationships among the turnoff wave bands lambda_turnoff (longward of
which significant IR excesses above the stellar photosphere are observed), the
excess spectral index alpha_excess at lambda <~ 24 microns, and the disk inner
radius R_in (from SED modeling) for YSOs of different evolutionary stages, we
found that the median and standard deviation of alpha_excess of YSOs with
optically thick disks tend to increase with lambda_turnoff, especially at
lambda_turnoff >= 5.8 microns, whereas the median fractional dust luminosities
L_dust/L_star tend to decrease with lambda_turnoff. This points to an
inside-out disk clearing of small dust grains. Moreover, a positive correlation
between alpha_excess and R_in was found at alpha_excess > ~0 and R_in > ~10
the dust sublimation radius R_sub, irrespective of lambda_turnoff,
L_dust/L_star and disk flaring. This suggests that the outer disk flaring
either does not evolve synchronously with the inside-out disk clearing or has
little influence on alpha_excess shortward of 24 microns. About 23% of our YSO
disks are classified as transitional disks, which have lambda_turnoff >= 5.8
microns and L_dust/L_star >10^(-3). The transitional disks and full disks
occupy distinctly different regions on the L_dust/L_star vs. alpha_excess
diagram. Taking L_dust/L_star as an approximate discriminator of disks with
(>0.1) and without (<0.1) considerable accretion activity, we found that 65%
and 35% of the transitional disks may be consistent with being dominantly
cleared by photoevaporation and dynamical interaction respectively. [abridged]Comment: 31 pages, 13 figures, 2 tables. To appear in a special issue of RAA
on LAMOST science
Phosphorus adsorption and desorption characteristics and its response to soil properties of black soil under long-term different fertilization
editorial reviewedObjective: Fertilizer is generally added to agricultural soil to meet the needs of crop production, but long-term over fertilization changes soil phosphorus (P) pool and soil properties. This study evaluated the characteristics change of P adsorption and desorption and its response to soil properties under long-term fertilization, to do a favor to provide theoretical basis of rational fertilizer application and improve the P availability of black soil. Method: Four treatments, including no fertilizer (CK), urea and potash sulphate (NK), urea, super-calcium phosphate and potash sulphate (NPK), and NPK plus pig manure (NPKM), were investigated in a 21-year (1989-2010) long-term fertilization experiment at Gongzhuling (Jilin Province) of China. The crop of cropping system was maize. Soil samples were collected in 1990, 2000 and 2010 at 0-20 cm depth to analyze soil properties and to measure soil P adsorption and desorption characteristics. Langmuir equation was used to fit the P adsorption curve, and then the maximum adsorption capacity (Qmax), adsorption constant (K), buffering capacity of soil P (MBC), and P sorption saturation (DPS) were calculated according to Langmuir equation. Result: There was a good fitness between the P adsorption curve and Langmuir equation (R2=0.93-0.99, P<0.01). There existed difference for P adsorption and desorption characteristic under the four treatments. Over time, compared with initial year, for CK and NK treatments, the Qmax value increased by 1.83 and 1.61 times, MBC value increased by 0.80% and 49.40%, DPS value decreased by 92.04% and 87.50%, Readily Desorbable Phosphorus (RDP) value decreased by 20.00% and 82.83%, respectively; for NPK treatment, Qmax and DPS value increased by 81.87% and 79.56%, MBC and RDP value decreased by 79.37% and 48.57%, respectively, while under NPKM treatment, the Qmax and MBC value decreased by 33.35% and 78.52%, DPS and RDP values increased by 11.36 and 1.48 times, respectively. After 21 years experiments, compared with CK and NPK treatments, the Qmax and MBC value of NPKM treatment decreased by 64.66% and 49.52%, 81.87% and 79.56%, respectively; the DPS and RDP value of NPKM treatment increased by 110 and 3.81 times, 4.36 times and 78.57%, respectively. Compared with other treatments, the Total-P, Olsen-P, soil organic matter (SOM) and CaCO3 contents increased and SSA decreased significantly, but the pH, free Fe2O3 and Al2O3 value kept unchanged under NPKM treatment. RDA test showed that SOM and Total-P were the main factors that explained 49.5% and 18.7% of the total variation (P<0.05) which caused the difference of P adsorption desorption characteristic parameters among four treatments. Conclusion: Long-term combination of NPK fertilizers with manures could significantly increase SOM and P accumulation contents, decrease the soil adsorption capacity and increase desorption capacity, and improve P availability in soil, but it significantly increased the DPS value, easily thereby caused the risk of phosphorus loss. Therefore, various management practices and inorganic and organic P fertilizer input amounts should be considered to reduce P losses from this area
HDAC8 Inhibition Specifically Targets Inv(16) Acute Myeloid Leukemic Stem Cells by Restoring p53 Acetylation
SummaryAcute myeloid leukemia (AML) is driven and sustained by leukemia stem cells (LSCs) with unlimited self-renewal capacity and resistance to chemotherapy. Mutation in the TP53 tumor suppressor is relatively rare in de novo AML; however, p53 can be regulated through post-translational mechanisms. Here, we show that p53 activity is inhibited in inv(16)+ AML LSCs via interactions with the CBFβ-SMMHC (CM) fusion protein and histone deacetylase 8 (HDAC8). HDAC8 aberrantly deacetylates p53 and promotes LSC transformation and maintenance. HDAC8 deficiency or inhibition using HDAC8-selective inhibitors (HDAC8i) effectively restores p53 acetylation and activity. Importantly, HDAC8 inhibition induces apoptosis in inv(16)+ AML CD34+ cells, while sparing the normal hematopoietic stem cells. Furthermore, in vivo HDAC8i administration profoundly diminishes AML propagation and abrogates leukemia-initiating capacity of both murine and patient-derived LSCs. This study elucidates an HDAC8-mediated p53-inactivating mechanism promoting LSC activity and highlights HDAC8 inhibition as a promising approach to selectively target inv(16)+ LSCs
A logical network-based drug-screening platform for Alzheimer’s disease representing pathological features of human brain organoids
Developing effective drugs for Alzheimer’s disease (AD), the most common cause of dementia, has been difficult because of complicated pathogenesis. Here, we report an efficient, network-based drug-screening platform developed by integrating mathematical modeling and the pathological features of AD with human iPSC-derived cerebral organoids (iCOs), including CRISPR-Cas9-edited isogenic lines. We use 1300 organoids from 11 participants to build a high-content screening (HCS) system and test blood–brain barrier-permeable FDA-approved drugs. Our study provides a strategy for precision medicine through the convergence of mathematical modeling and a miniature pathological brain model using iCOs. © 2021, The Author(s).1
Prevalence and Determinants of Metabolic Syndrome among Women in Chinese Rural Areas
BACKGROUND AND AIMS: Metabolic syndrome (MS) is prevalent in recent years but few data is reported in the rural areas in China. The aim of this study was to examine MS prevalence and its risk factors among women in rural China. METHODS AND RESULTS: The Nantong Metabolic Syndrome Study (NMSS), a population based cross-sectional study, was conducted during 2007-2008 in Nantong, China. In person interviews, blood glucose and lipid measurements were completed for 13,505 female participants aged 18-74 years. The International Diabetes Federation (IDF), the US Third Report of the National Cholesterol Education Program, the Adult Treatment Panel (ATPIII) and modified ATPIII for Asian population has determined three criteria of MS. These criteria for MS were used and compared in this study. The prevalence of MS was 22.0%, 16.9% and 23.3% according to IDF, ATPIII and ATPIII-modified criteria, respectively. Levels of agreement of these criteria for MS were above 0.75. We found that vigorous-intensity of occupational physical activity was associated with a low prevalence of MS with OR of 0.76 (95% confidence interval (CI): 0.63-0.91). Rice wine drinkers (alcohol >12.8 g/day) had about 34% low risks of developing MS with OR of 0.66 (95% CI: 0.48-0.91), compared with non-drinkers. Odds ratio of MS was 1.81 (95% CI: 1.15-2.84) in women who smoked more than 20 pack-years, compared to non-smokers. Odds ratio of MS was 1.56 (95% CI: 1.25-1.95) in women who had familial history of diseases, including hypertension, diabetes and stroke, compared to women without familial history of those diseases. CONCLUSION: MS is highly prevalent among women in rural China. Both physical activity and rice wine consumption play a protective role, while family history and smoking are risk factors in MS development. Educational programs should be established for promoting healthy lifestyles and appropriate interventions in rural China
A highly hydrophilic water-insoluble nanofiber composite as an efficient and easily-handleable adsorbent for the rapid adsorption of cesium from radioactive wastewater
Herein, we report a new Prussian blue nanoparticle (PBNPs) incorporated polyvinyl alcohol (PVA) composite nanofiber (c-PBNPs/PVA) for the rapid adsorption of cesium (Cs) from radioactive wastewater. Initially, various electrospinning parameters such as solvent, PVA wt%, PBNPs wt% and glutaraldehyde (GA) wt% were extensively optimized to obtain a better physicochemical property of the c-PBNPs/PVA. In order to improve the water insoluble nature of the PVA, post cross-linking was carried out for the c-PBNPs/PVA using glutaraldehyde (GA) and HCl vapor as the cross-linker and catalyst, respectively. SEM images revealed the smooth and continuous morphology of the c-PBNPs/PVA composite nanofibers with diameters of 200–300 nm and lengths up to several millimeters. TEM images confirmed homogeneous dispersion and good incorporation of PBNPs into the PVA matrix. The amorphous nature of the c-PBNPs/PVA was confirmed by the XRD analysis. FT-IR spectra showed successful cross-linking of PVA with GA. It was found that the prepared composite nanofiber is highly hydrophilic and water-insoluble. The c-PBNPs/PVA showed an excellent and faster Cs adsorption rate of 96% after only 100 min. These results are comparable to those previously reported. After the Cs adsorption test, the c-PBNPs/PVA composite nanofiber can be easily separated from the wastewater.ArticleRSC ADVANCES. 4(103):59571-59578 (2014)journal articl
Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke
Importance
It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy.
Objective
To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO.
Design, Setting, and Participants
This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy.
Main Outcomes and Measures
The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours.
Results
Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo.
Conclusions and Relevance
Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172
Acute toxicity, respiratory reaction, and sensitivity of three cyprinid fish species caused by exposure to four heavy metals.
Using 3 cyprinid fish species zebra fish, rare minnow, and juvenile grass carp, we conducted assays of lethal reaction and ventilatory response to analyze sensitivity of the fish to 4 heavy metals. Our results showed that the 96 h LC50 of Hg(2+) to zebra fish, juvenile grass carp, and rare minnow were 0.14 mg L(-1), 0.23 mg L(-1), and 0.10 mg L(-1), respectively; of Cu(2+)0.17 mg L(-1), 0.09 mg L(-1), and 0.12 mg L(-1) respectively; of Cd(2+)6.5 mg L(-1), 18.47 mg L(-1), 5.36 mg L(-1), respectively; and of Zn(2+)44.48 mg L(-1), 31.37 mg L(-1), and 12.74 mg L(-1), respectively. Under a 1-h exposure, the ventilatory response to the different heavy metals varied. Ventilatory frequency (Vf) and amplitude (Va) increased in zebra fish, juvenile grass carp, and rare minnows exposed to Hg(2+) and Cu(2+) (P<0.05), and the Vf and Va of the 3 species rose initially and then declined when exposed to Cd(2+). Zn(2+) had markedly different toxic effects than the other heavy metals, whose Vf and Va gradually decreased with increasing exposure concentration (P<0.05). The rare minnow was the most highly susceptible of the 3 fish species to the heavy metals, with threshold effect concentrations (TEC) of 0.019 mg L(-1), 0.046 mg L(-1), 2.142 mg L(-1), and 0.633 mg L(-1) for Hg(2+), Cu(2+), Cd(2+), and Zn(2+), respectively. Therefore, it is feasible to use ventilatory parameters as a biomarker for evaluating the pollution toxicity of metals and to recognize early warning signs by using rare minnows as a sensor
Experimental Study on Radiation Noise Frequency Characteristics of a Centrifugal Pump with Various Rotational Speeds
To investigate the radiation noise frequency characteristics of a centrifugal pump under various rotational speeds, a noise measurement system was established in a soundproof room. Sixteen monitoring points were evenly arranged in a circumferential direction around the pump and the sound pressure levels (SPLs) at different monitoring points were measured by a microphone, then the changing patterns of radiation noise in a wide frequency range and at certain frequencies were studied. The results reveal that the SPLs reach a maximum between 1000 and 2000 Hz, while SPLs are lower in other frequency ranges. Additionally, the acoustic energy was introduced to determine the proportion of radiation noise in different frequency ranges to overall noise. When rotational speed increases from 1700 to 2900 rpm, the proportion of acoustic energy between 1000 and 2000 Hz is higher than 0.50 and shows an increasing trend. Meanwhile, the proportion between 0 and 1000 Hz is about 0.30 and decreases gradually, while that between 2000 and 8000 Hz is about 0.12 and shows little change. Also, the increase in radiation noise at high frequency is higher than that at low frequency. This study could provide theoretical guidance for research regarding radiation noise prediction and control technology at different frequencies of centrifugal pumps
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