Occurrence of booster biocides in the global waters and a tiered assessment for their ecological risk to the aquatic system

The concentration data and toxicity data of seven booster biocides were collected, and a tiered assessment was performed to evaluate their ecological risk. Results indicated that Diuron and Irgarol 1051 had the highest concentrations; Irgarol 1051 and GS26575 were the most toxic. A tiered risk assessment implied that the risk of six biocides and one degradation product followed the order: Irgarol 1051 > GS26575 > Diuron (or Diuron > GS26575) > DCOIT > Dichlofluanid ≈ Chlorothalonil > BIT. Apparently, the top three biocides with the highest risk were Irgarol 1051, GS26575 and Diuron. The 70.6%, 33.3% and 6.76% concentration data of Irgarol 1051, GS26575 and Diuron behaved high risk, respectively. They could impact 2.54%-14.4% species in the common case, and impact 7.08%-48.1% species in the worst case. Irgarol 1051 posed great risk to China, Brazil and UK; GS26575 posed no significantly different risk to different countries; Diuron posed high risk to Spain and Italy.</p

Mathematical Model for Cyclodextrin Alteration of Bioavailability of Organic Pollutants

While many cyclodextrin-based applications have been developed to assess or enhance bioavailability of organic pollutants, the choice of cyclodextrin (CD) is largely empirical, with little consideration of pollutant diversity and environmental matrix effects. This study aimed at developing a mathematical model for quantifying CD alteration of bioavailability of organic pollutants. Cyclodextrin appears to have multiple effects, together contributing to its bioavailability-enhancing property. Cyclodextrin is adsorbed onto the adsorbent matrix to different extents. The adsorbed CD is capable of sequestrating organic pollutants, highlighting the role of a pseudophase similar to solid environmental matrix. Aqueous CD can reduce adsorption of organic pollutants via inclusion complexation. The two effects cancel each other to a certain degree, which determines the levels of organic pollutants dissolved (comprising freely dissolved and CD-included forms). Additionally, the CD-included form is nearly identical in biological activity to the free form. A mathematical model of one variable (i.e., CD concentration) was derived to quantify effects of CD on the bioavailability of organic pollutants. Model analysis indicates that alteration of bioavailability of organic pollutants by CD depends on both CD (type and level) and environmental matrix. The selection of CD type and amendment level for a given application may be predicted by the model

Intermediate mechanism test.

The “dual circulation” development pattern is a major economic strategy proposed by China. Using samples gathered from firms located in the Haidian Science and Technology Park in Zhongguancun between 2013 and 2019, this paper constructs an index system for measuring the degree of synergy of the dual circulation coupling of the firms, and then uses the Cloglog survival model to empirically verify its effect on the survival of firms. It is found that the dual circulation coupling synergy of firms significantly contributes to firm survival, a finding that still holds after robustness tests. Mechanism tests show that firm dual circulation coupling synergies contribute to firm survival by promoting firm innovation, market demand, and resource allocation efficiency. Further analysis reveals that the coupled synergy of the dual circulation of firms contributes more significantly to the survival of growing and mature firms, MSMEs, private firms and non-start-up firms. This paper is the first to measure dual circulation. It provides micro-theoretical mechanisms and relevant empirical evidence for the dual circulation coupling synergy for firm survival.</div

K-M survival curve.

The solid line represents the K-M estimate for the low coupling synergy firm, and the dotted line represents the K-M estimate for the high coupling synergy firm. The survival curves of high dual circulation coupling synergy firms are higher than those of low dual circulation coupling synergy firms.</p

Indicator system of the firm dual circulation system.

Indicator system of the firm dual circulation system.</p

Estimated firm survival function.

The “dual circulation” development pattern is a major economic strategy proposed by China. Using samples gathered from firms located in the Haidian Science and Technology Park in Zhongguancun between 2013 and 2019, this paper constructs an index system for measuring the degree of synergy of the dual circulation coupling of the firms, and then uses the Cloglog survival model to empirically verify its effect on the survival of firms. It is found that the dual circulation coupling synergy of firms significantly contributes to firm survival, a finding that still holds after robustness tests. Mechanism tests show that firm dual circulation coupling synergies contribute to firm survival by promoting firm innovation, market demand, and resource allocation efficiency. Further analysis reveals that the coupled synergy of the dual circulation of firms contributes more significantly to the survival of growing and mature firms, MSMEs, private firms and non-start-up firms. This paper is the first to measure dual circulation. It provides micro-theoretical mechanisms and relevant empirical evidence for the dual circulation coupling synergy for firm survival.</div

Mechanical and Gas Barrier Properties of Structurally Enhanced Poly(ethylene terephthalate) by Introducing 1,6-Hexylenediamine Unit

1,6-Hexylenediamine (HMDA) was chosen to replace part of ethylene glycol to develop a novel poly­(ethylene terephthalate) structure with amide bonds. Four kinds of poly­(ester amide)­analogues (p-ETA) with different contents of amide bonds (1–4 mol %) were successfully synthesized via a new simple synthesis procedure. It was proved that the thermal stability and mechanical properties were significantly enhanced because of the introduction of amide bond units. More importantly, adding a small amount (1 mol %) of HMDA could effectively accelerate the orderly arrangement of molecular chains and formation of crystal nuclei proved by differential scanning calorimetry, X-ray diffraction, and polarized optical microscopy test results. It showed that the calendered p-ETA films acted as a good barrier to water and oxygen, expanding its application as packaging materials. Experimental results indicated that the introduction of amide bond units substantially promoted the overall performances of poly­(ethylene terephthalate), such as crystallinity (28.4 vs 14.1%), tensile strength (60.9 vs 55.7 MPa), elongation at break (381 vs 226.8%), and so forth

Estimated survival function of observed firms.

The “dual circulation” development pattern is a major economic strategy proposed by China. Using samples gathered from firms located in the Haidian Science and Technology Park in Zhongguancun between 2013 and 2019, this paper constructs an index system for measuring the degree of synergy of the dual circulation coupling of the firms, and then uses the Cloglog survival model to empirically verify its effect on the survival of firms. It is found that the dual circulation coupling synergy of firms significantly contributes to firm survival, a finding that still holds after robustness tests. Mechanism tests show that firm dual circulation coupling synergies contribute to firm survival by promoting firm innovation, market demand, and resource allocation efficiency. Further analysis reveals that the coupled synergy of the dual circulation of firms contributes more significantly to the survival of growing and mature firms, MSMEs, private firms and non-start-up firms. This paper is the first to measure dual circulation. It provides micro-theoretical mechanisms and relevant empirical evidence for the dual circulation coupling synergy for firm survival.</div

Definitions and descriptive statistics of the variables used in the empirical analysis.

Definitions and descriptive statistics of the variables used in the empirical analysis.</p