The Effect of Notch and Molecular Weight on the Impact Fracture Behavior of Polycarbonate.

The impact protection applications of polycarbonate (PC) products are gradually increasing. Due to the high sensitivity of PC to notches, research on notch impacts has become very important. In this paper, the impact performance of PC with two different molecular weights under different notch states was investigated. Three notch size factors, namely notch tip radius, notch angle, and notch center depth, were selected to design orthogonal experiments and research impact toughness. Subsequently, a single-factor study was conducted on the impact radius at the tip of the notch, which was the most important factor affecting the impact performance. Research shows that the brittle-ductile-transition tip radius of high-molecular-weight PC is 0.15 mm, and it has a higher impact toughness than low-molecular-weight PC during the brittle fracture process. The brittle-ductile-transition tip radius of lower molecular weight is 0.25 mm, while low-molecular-weight PC has a higher impact toughness during the ductile fracture process. The brittle and ductile fracture mechanisms of PC with different molecular weights were analyzed by observing the stress changes and cross-sectional morphology.

Enhancing the growth of thermophilic Bacillus licheniformis YYC4 by low-intensity fixed-frequency continuous ultrasound.

The effect of low-intensity fixed-frequency continuous ultrasound (LIFFCU) on the growth of Bacillus licheniformis YYC4 was investigated. The changes in morphology and activity of the organism, contributing to the growth were also explored. Compared with the control, a significant increase (48.95%) in the biomass of B. licheniformis YYC4 (at the logarithmic metaphase) was observed following the LIFFCU (28 kHz, 1.5 h and 120 W (equivalent to power density of 40 W/L)) treatment. SEM images showed that ultrasonication caused sonoporation, resulting in increased membrane permeability, evidenced by increase in cellular membrane potential, electrical conductivity of the culture, extracellular protein and nucleic acid, and intracellular Ca2+ content. Furthermore, LIFFCU action remarkably increased the extracellular protease activity, volatile components of the culture medium, microbial metabolic activity, and spore germination of the strain. Therefore, LIFFCU could be used to efficiently promote the growth of targeted microorganisms.

The spatial distribution and characterization of phosphorus and nitrogen in a water-carrying lake: a case study of Lake Jiaogang, China.

The sources of P and N in water-carrying lakes include exogenous input and endogenous release. However, the influence of pollution from different sources on the dynamic distribution of N and P at the sediment-water interface in water-carrying lakes remains unclear. The objectives of this study were to investigate the differences in dynamic distribution characteristics of P compounds and N elements in Lake Jiaogang, a major water-carrying lake in eastern China. Four functional regions with different types of pollutant sources and different kinds of aquatic plants were selected to study the distribution of total P (TP), inorganic P, organic P, ammonium (NH4+-N), and nitrate (NO3--N). The results revealed that regions with internal-source pollutants contained the highest concentration of TP, Ca-P, and Fe-P with high concentrations. L-P, Al-P, mostly organic P, and soluble reactive phosphorous (SRP), the region with internal-source pollutants were lower than that with the imported-source pollutant. The concentration of dissolved NH4+-N showed high in regions with imported-source pollutants, however, in regions with internal-source pollutants, the dissolved NO3--N was with the highest concentration. Overall, P from upstream was still dominant in the sediments despite uptake by the aquatic plants. SRP showed high concentration in regions with imported-source pollutants due to the imported pollution and the improved bioavailability by plant root exudates. Feces and feed residues from aquatic livestock breeding resulted in the highest concentration of TN, NH4+-N, and dissolved NO3--N in the sediments of the region with internal-source pollutants. High concentrations of dissolved NH4+-N were due to the input of N from imported source pollutants. This study provides insights into the contributions of P and N to the eutrophication of the water-carrying lake.

The selective breeding and mutagenesis mechanism of high-yielding surfactin Bacillus subtilis strains with atmospheric and room temperature plasma.

BACKGROUND: Surfactin, a good biological surfactant, is derived from the metabolites of microorganisms. However, the ability of natural strains to produce surfactin is low, and so the presented study aimed to use a novel mutagenesis technology to increase their yields. RESULTS: Atmospheric and room temperature plasma (ARTP) was used to conduct mutation breeding of Bacillus subtilis CICC 10721, and a mutant strain M45 with a higher surfactin yield of 34.2% and a stable subculture was screened out. From the fermentation kinetics study, it was found that the maximum cell dry weight, maximum growth rate and surfactin synthesis parameters of the mutant strain M45 were all greater than that of the original strain. Scanning electron microscope and laser scanning confocal microscope observations showed that the spore morphology changed after ARTP treating, and the intracellular Ca2+ concentration of the mutant increased. Genome resequencing analysis showed that 66 single nucleotide poymorphism non-synonymous mutation sites occurred in M45, and the identification results of the fermentation broth extract from M45 showed that it is composed of C12 -C16 surfactin. CONCLUSION: ARTP mutagenesis was found to change the morphology of bacteria, membrane permeability and genes related to the synthesis and secretion of surfactin. The present study provides a basis for industrial production of surfactin and an understanding of the mutagenesis mechanism. © 2021 Society of Chemical Industry.

The mTORC1-eIF4F axis controls paused pluripotency.

Mouse embryonic stem cells (mESCs) can self-renew indefinitely and maintain pluripotency. Inhibition of mechanistic target of rapamycin (mTOR) by the kinase inhibitor INK128 is known to induce paused pluripotency in mESCs cultured with traditional serum/LIF medium (SL), but the underlying mechanisms remain unclear. In this study, we demonstrate that mTOR complex 1 (mTORC1) but not complex 2 (mTORC2) mediates mTOR inhibition-induced paused pluripotency in cells grown in both SL and 2iL medium (GSK3 and MEK inhibitors and LIF). We also show that mTORC1 regulates self-renewal in both conditions mainly through eIF4F-mediated translation initiation that targets mRNAs of both cytosolic and mitochondrial ribosome subunits. Moreover, inhibition of mitochondrial translation is sufficient to induce paused pluripotency. Interestingly, eIF4F also regulates maintenance of pluripotency in an mTORC1-independent but MEK/ERK-dependent manner in SL, indicating that translation of pluripotency genes is controlled differently in SL and 2iL. Our study reveals a detailed picture of how mTOR governs self-renewal in mESCs and uncovers a context-dependent function of eIF4F in pluripotency regulation.

Factors influencing the financing behavior of large professional households engaged in green agricultural production in China.

Green agriculture is the direction of sustainable development of China's modern agriculture and the inherent requirement of taking the road of characteristic new agricultural modernization. As one of the main bodies of new agricultural management, professional large households are of great significance to lead the development of efficient agriculture and accelerate the development of green agricultural economy in Heilongjiang. Therefore, based on the theory of planned behavior, this article includes 275 major professional households in Heilongjiang Province as a sample of demonstration counties (cities) for green, high-quality, and efficient creation, combined with field research data and structural equation model, and discusses the willingness of large professional households to participate in green agricultural production financing and behavioral factors and mechanisms of action. The perceived behavior control (PBC), attitude toward the behavior (AB), and subjective norms (SNs) of large professional households to engage in green agricultural production determine their financing intentions (FNs), which further determines their financing behavior (FB). The results show that PBC, AB, and SN have a significant positive impact on the FN of large professional households, and further indirectly affect the FB. It should be noted that SNs have the most significant impact on the FN of large professional households to participate in green agricultural production. Therefore, it is necessary to establish effective government propaganda measures and preferential policies, improve the awareness of the importance of green agricultural production financing, and create a good social atmosphere for agricultural sustainable development and active participation in financing. The purpose of this study is to provide a reference for policymakers to formulate relevant policies to cultivate major professional households and develop green agricultural economy in Heilongjiang Province.

Interactions of heavy metal elements across sediment-water interface in Lake Jiaogang.

Heavy metal pollution in lake systems has arisen plenty of threats for public health because of its high toxicity, persistence, and bioaccumulation. Whereas heavy metals are inextricably linked with bioavailability in pore water and overlying water. Lake Jiaogang is classified as an important water-carrying lake situated in the northern part of the Anhui Province China. In recent years, water quality in this lake declined due to increasing fishery aquaculture, livestock, and tourism. This study aims to bring insight into the interactions of heavy metal elements across sediment-water interface in Lake Jiaogang. Four representative regions were selected, more than ten heavy metals were chosen to quantify by the Community Bureau of Reference, diffusive gradient in thin-film (DGT), and high-resolution pore water equilibrators. The results showed that most heavy metals corresponded with the reducible fraction, acid-soluble fraction, and oxidizable fraction in the Eastern area (sample 3#) and aquaculture area (sample 4#) were higher than that of emergent plant area (sample 1#), and floating plant area (sample 2#). The average fluxes of heavy metals (except Ni and Zn in sample 3#, F value > 0 pg/cm2/d) in the four sampling sites were observed in the lower reaches (F value < 0 pg/cm2/d). The vertical distribution of heavy metals was extracted by DGT, such as As (exclude 2#), Co, Fe, Mn, and Zn (contain 4#) showed an increased content with increasing depth in the four sampling sites. In the pore and overlying water, concentrations of heavy metals from the sample 3# and 4# were higher than those of sample 1# and 2#. Heavy metal pollution in anthropogenic activity areas was higher than those in areas with ecological vegetation, and risk control in this area should be strengthened.

JMJD3 acts in tandem with KLF4 to facilitate reprogramming to pluripotency.

The interplay between the Yamanaka factors (OCT4, SOX2, KLF4 and c-MYC) and transcriptional/epigenetic co-regulators in somatic cell reprogramming is incompletely understood. Here, we demonstrate that the histone H3 lysine 27 trimethylation (H3K27me3) demethylase JMJD3 plays conflicting roles in mouse reprogramming. On one side, JMJD3 induces the pro-senescence factor Ink4a and degrades the pluripotency regulator PHF20 in a reprogramming factor-independent manner. On the other side, JMJD3 is specifically recruited by KLF4 to reduce H3K27me3 at both enhancers and promoters of epithelial and pluripotency genes. JMJD3 also promotes enhancer-promoter looping through the cohesin loading factor NIPBL and ultimately transcriptional elongation. This competition of forces can be shifted towards improved reprogramming by using early passage fibroblasts or boosting JMJD3's catalytic activity with vitamin C. Our work, thus, establishes a multifaceted role for JMJD3, placing it as a key partner of KLF4 and a scaffold that assists chromatin interactions and activates gene transcription.

ß-Catenin safeguards the ground state of mousepluripotency by strengthening the robustness of the transcriptional apparatus.

Mouse embryonic stem cells cultured with MEK (mitogen-activated protein kinase kinase) and GSK3 (glycogen synthase kinase 3) inhibitors (2i) more closely resemble the inner cell mass of preimplantation blastocysts than those cultured with SL [serum/leukemia inhibitory factor (LIF)]. The transcriptional mechanisms governing this pluripotent ground state are unresolved. Release of promoter-proximal paused RNA polymerase II (Pol2) is a multistep process necessary for pluripotency and cell cycle gene transcription in SL. We show that ß-catenin, stabilized by GSK3 inhibition in medium with 2i, supplies transcriptional coregulators at pluripotency loci. This selectively strengthens pluripotency loci and renders them addicted to transcription initiation for productive gene body elongation in detriment to Pol2 pause release. By contrast, cell cycle genes are not bound by ß-catenin, and proliferation/self-renewal remains tightly controlled by Pol2 pause release under 2i conditions. Our findings explain how pluripotency is reinforced in the ground state and also provide a general model for transcriptional resilience/adaptation upon network perturbation in other contexts.

Field observation and simulation experiments on nutrient transformation during phytoplankton-derived particulate matter deposition.

Phytoplankton-derived particulate matter (PPM) is the active component of the solid particles in eutrophic shallow lakes. To date, understanding of the degradation characteristics of PPM and the effect of degradation products on nutrient cycling in water are limited. In this study, field observations and simulation experiments were carried out to elaborate the nutrient transformation during phytoplankton-derived particulate matter deposition in the cyanobacterial blooming area of Lake Taihu. Results showed that the deposition of the PPM was strongly facilitated by the cyanobacterial bloom and the sediment resuspension. The main variation characteristics of phosphorus (P) species in PPM are shown in the increase of Ortho-P and the decrease of biodegradable phosphorus (Poly-P, DNA-P) during the deposition of PPM. The degradation of the PPM resulted in the release of dissolved nitrogen (N) and P to the water body. The conversion of easily degradable particulate N and P in the PPM to ammonium nitrogen (NH3-N) and soluble reactive phosphorus were believed to be responsible for this phenomenon. The cycling of nutrients and the cyanobacterial bloom status might therefore be altered because of the deposition and degradation of PPM. More considerations should be given on this process in future works.

mTORC1-PGC1 axis regulates mitochondrial remodeling during reprogramming.

Metabolic reprogramming, hallmarked by enhanced glycolysis and reduced mitochondrial activity, is a key event in the early phase of somatic cell reprogramming. Although extensive work has been conducted to identify the mechanisms of mitochondrial remodeling in reprogramming, many questions remain. In this regard, different laboratories have proposed a role in this process for either canonical (ATG5-dependent) autophagy-mediated mitochondrial degradation (mitophagy), noncanonical (ULK1-dependent, ATG5-independent) mitophagy, mitochondrial fission or reduced biogenesis due to mTORC1 suppression. Clarifying these discrepancies is important for providing a comprehensive picture of metabolic changes in reprogramming. Yet, the comparison among these studies is difficult because they use different reprogramming conditions and mitophagy detection/quantification methods. Here, we have systematically explored mitochondrial remodeling in reprogramming using different culture media and reprogramming factor cocktails, together with appropriate quantification methods and thorough statistical analysis. Our experiments show lack of evidence for mitophagy in mitochondrial remodeling in reprogramming, and further confirm that the suppression of the mTORC1-PGC1 pathway drives this process. Our work helps to clarify the complex interplay between metabolic changes and nutrient sensing pathways in reprogramming, which may also shed light on other contexts such as development, aging and cancer.

Synthesis, crystal structure, photoluminescence property of a series of 3d-4f coordination supramolecular complexes.

A series of 3d-4f heterobinuclear complexes were constructed by employing the 2,2'-bipy (2,2'-bipy=2,2'-bipyridine) ligand and corresponding metal ions (M(II)/Ln(III), M=Co(II), Cu(II) and Zn(II); Ln(III)=Nd(III), Sm(III), Eu(III) and Tb(III)). Elemental analyses, IR, UV-vis-NIR spectra, PXRD and single crystal X-ray diffraction analysis reveal that complexes 1-4, 5-8, and 9-12 are isomorphous, respectively. The zero-dimensional structures are further connected to 2D or 3D supramolecular network structures via extensive intermolecular hydrogen bonds. Luminescence studies for the heterobinuclear complexes containing Sm(III), Eu(III) and Tb(III) reveal that the chromophoric composed of Zn(II)/L may efficiently sensitize the luminescence of the rare earth cations which acts as an antenna, whereas the existence of Cu(II) leads to the quenching of the luminescence of Ln(III) ions.

d7 /d8 Metal Complexes Constructed from 2,6-Bis(2-benzimidazolyl)pyridyl or 2,6-Di-(pyrazol-3-yl)pyridine Derivatives: Synthesis, Structure, Characterization, and Photocatalytic Activity.

By introducing 2,6-bis(2-benzimidazolyl)pyridyl and 2,6-di-(pyrazol-3-yl)pyridine derivatives as ligand in the reaction system, three new transition-metal coordination complexes have been successfully synthesized, namely, [Co(HL1 )2 ] (1), [Ni(HL1 )2 ] (2), and [Ni3 (H2 L2 )2 ⋅(HL2 )2 ]⋅(OH)3 ⋅(Ac)⋅H2 O (3) (H2 L1 =2,6-bis(benzimidazol-2-yl)pyridine and H2 L2 =2,6-di-(5-phenyl-1H-pyrazol-3-yl)pyridine). They are all characterized by elemental analysis, IR spectroscopy, UV absorption spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Structural analysis shows that the structures of complexes 1 and 2 are similar. They are constructed from one metal (Co, Ni) atom and two 2,6-bis(benzimidazol-2-yl)pyridine ligands (HL1 - ); the HL1 - ligand is in the tridentate coordination mode with N3 donors. Complex 3 is a trinuclear Ni complex with four 2,6-di-(5-phenyl-1H-pyrazol-3-yl)pyridine (H2 L2 ) ligands, in which the H2 L2 possesses two coordination fashions: terminal tridentate and bridging tetradentate. In addition, the surface photovoltage spectroscopy and photocatalytic activities of complexes 1-3 were investigated in detail. The results reveal that complex 3 possesses higher photocatalytic activity.

Pharmacokinetics of ambroxol and clenbuterol tablets in healthy Chinese volunteers.

OBJECTIVE: To investigate the pharmacokinetics of Ambroxol and Clenbuterol Tablets in Chinese healthy volunteers after a single or multiple dosages oral administration. METHODS: A total of 9 healthy adult subjects were given Ambroxol and Clenbuterol Tablets in a single dosage or multiple dosages respectively. LC/MS/MS were used for the determination of Ambroxol and Clenbuterol of in plasma. The important pharmacokinetic parameters were calculated by DAS 2.0 software (compartment model). RESULTS: Single and multiple dosage groups of Ambroxol and Clenbuterol were all fitted two-compartment model. The pharmacokinetics fitted first order kinetics process. No difference in pharmacokinetics of Ambroxol in single and multiple dosage groups volunteers was observed, Which showed no marked changes, suggesting that multiple dosing did not influence the velocity of drug metabolism. Moreover, parameters of Clenbuterol had significant difference between the single and multiple dosage groups (P<0.05), showing there was accumulation in the body. 9 subjects had completed single or multiple dosages oral administration test, with no adverse drug reactions appeared during the test. CONCLUSION: There was no obvious accumulation of Ambroxol after repeated dosing. But obvious accumulation of Clenbuterol was noted in multiple-dose administration. The established method is sensitive, accurate, reliable and specific, and it can meet the requirement of clinical pharmacokinetic trial.

Synthesis, structure, fluorescence spectra study of two kinds of coordination supramolecular zinc compounds.

Two novel compounds [Zn(IAA)2(phen) (HIAA=indole-3-acetic acid, phen=1,10-phenanthroline) (1) and [Zn(IAA)2(4,4'-bipy)](4,4'-bipy=4,4'-bipyridine) (2) were synthesized by the reaction of Zn(Ac)2·2H2O or Zn(SO4)·4H2O as a metal source, HIAA as the first ligand and phen or 4,4'-bipy as the second ligand in the system of methanol or the mixed solution of methanol and water at room temperature. They were characterized by elemental analysis, IR spectroscopy, UV-vis spectra and single-crystal X-ray diffraction. Structural analysis shows that the center metal Zn(II) for the compound 1 is four-coordinated, displaying a distorted tetrahedron; the metal center coordinated model for compound 2 is similar to that of 1, in which the structural unit of Zn(IAA)2 was connected by bridging the 4, 4'- bipy ligand to form an infinite 1D chain. In the packing of the compounds, there are some hydrogen bonding interactions and by the hydrogen bonding, 1D and 2D supramolecular structures were formed. Additional, we have studied the fluorescent properties of the two compounds.

Pharmacokinetics and pharmacodynamics of febuxostat under fasting conditions in healthy individuals.

The aim of the present study was to investigate the pharmacokinetic and pharmacodynamic characteristics of febuxostat following the administration of single and multiple oral doses under fasting conditions to healthy individuals. Thirty-six healthy subjects were randomly divided into three groups, each containing 12 subjects (six male and six female) as follows: Group A, treated with a single oral dose of febuxostat (40 mg); group B, treated with a single oral dose of febuxostat (80 mg) followed by multiple oral doses of febuxostat for 7 days; and group C, treated with a single oral dose of febuxostat (120 mg). Blood samples were collected, and the plasma drug levels and serum uric acid (UA) concentrations were determined by clinical laboratory testing. Febuxostat displayed a linear pharmacokinetic profile for oral doses of 40 to 120 mg. Drug accumulation was not detected following multiple oral doses. When febuxostat was administered as single doses of 40, 80 and 120 mg, the 24-h UA concentration (UA24) values displayed a linear correlation with the dosage. The relationship between UA24 and the three single dose levels (40, 80 and 120 mg) was analyzed. The difference in UA24 between every single dose was significant (P<0.05). After 3 and 7 days of dosing, reductions of 46.67 and 52.69%, respectively, were observed in UA24. On day 7 of dosing, the mean reduction in the UA concentration was 51.83±7.00%. This study demonstrates that febuxostat reduces serum UA concentrations in a dose-linear manner.

[A cross-sectional study on injuries in residents from the countryside of Huanghe Delta rural areas].

OBJECTIVE: To study the incidence of injuries among residents living in the countryside of Huanghe delta area. METHODS: A household questionnaire survey was conducted to 15 276 residents in 20 villages of Dongying municipality of Shandong province with a stratified-cluster sampling on their injuries from March 1, 2002 to February 28, 2003. Data were analyzed with Excel 2000 and SPSS 11.0 software. RESULTS: The crude incidence of injuries was 5.90% in total, and the standardized incidence was 5.93%. It was higher in men (7.79%) than in women (4.03%). There were 19 deaths with 20 cripples. The standardized death rate was 122.56 per 100 000 with leading causes of injuries was blunt or by sharp articles (24.61%), traffic accident (24.17%), falls (22.62%) and animal bites (13.08%). Peak incidence of age group was high in 25 - 54 age group and 0 - 4 age group (> 6.0%). 267 cases (29.60%) inpatients had had about 15.89 days hospitalization for each case. Rest of each case with injury had 19.20 days of rest. Direct economic loss for treatment would cost 904.85 RMB Yuan and 10.15 days with care takers and 221.88 RMB for other cost. The potential years of life lost was 24 years, the working years of life lost was 19.6 year, the valued years of life lost was 8.7 year, and the standardized period expected years of life lost was 31.73 year. CONCLUSION: Injury was common and frequently occurred among residents in the countryside of rural Huanghe delta areas, that seriously endangered the health care systems and burden on families.