Traffic density, congestion externalities, and urbanization in China

<p>Although there is an abundant regional literature analyzing traffic congestion, only a few studies have explored extending such analysis with spatial effects. This study uses a dynamic spatial Durbin model and city-level panel data for the period 2003–14 to investigate the spatial spillover effects of traffic congestion on urbanization in China. The results show that there is an inverted ‘U’-shaped relationship between urbanization and traffic density in local and neighbouring cities, and congestion effects have appeared. In the short and long run, the spatial effects of traffic congestion have become an important force restricting the effective promotion of urbanization in China.</p

Substituent Effect of Phenolic Aldehyde Inhibition on Alcoholic Fermentation by Saccharomyces cerevisiae

Phenolic compounds significantly inhibit microbial fermentation of biomass hydrolysates. To understand the quantitative structure–inhibition relationship of phenolic aldehydes on alcoholic fermentation, the effect of 11 different substituted benzaldehydes on the final ethanol yield was examined. The results showed that the degree of phenolic benzaldehyde inhibition was strongly associated with the position of phenolic hydroxyl groups but not the number of phenolic hydroxyl groups. It was observed that <i>ortho</i>-substituted 2-hydroxybenzaldehyde resulted in 15–20-fold higher inhibition than the <i>meta</i>- or <i>para</i>-substituted analogues of 3- and 4-hydroxybenzaldehydes. From the correlation of the molecular descriptors to inhibition potency in yeast fermentation, we found a strong relationship between the octanol/water partition coefficient (log <i>P</i>) of aldehydes and the EC₅₀ value. The most inhibitory 2-hydroxybenzaldehyde has the highest log <i>P</i> and possesses an <i>ortho</i> −OH group capable of forming an intramolecular hydrogen bond, which can potentially increase the cell membrane permeability and toxicity. The results also indicated that the calculated free energy change between phenolic aldehydes and amino acids can be used to predict their structure–inhibitory activity relationship

Inhibitory Activity of Carbonyl Compounds on Alcoholic Fermentation by Saccharomyces cerevisiae

Aldehydes and acids play important roles in the fermentation inhibition of biomass hydrolysates. A series of carbonyl compounds (vanillin, syringaldehyde, 4-hydroxybenzaldehyde, pyrogallol aldehyde, and <i>o</i>-phthalaldehyde) were used to examine the quantitative structure–inhibitory activity relationship of carbonyl compounds on alcoholic fermentation, based on the glucose consumption rate and the final ethanol yield. It was observed that pyrogallol aldehyde and <i>o</i>-phthalaldehyde (5.0 mM) reduced the initial glucose consumption rate by 60 and 89%, respectively, and also decreased the final ethanol yield by 60 and 99%, respectively. Correlating the molecular descriptors to inhibition efficiency in yeast fermentation revealed a strong relationship between the energy of the lowest unoccupied molecular orbital (<i>E</i>_LUMO) of aldehydes and their inhibitory efficiency in fermentation. On the other hand, vanillin, syringaldehyde, and 4-hydroxybenzaldehyde (5.0 mM) increased the final ethanol yields by 11, 4, and 1%, respectively. Addition of vanillin appeared to favor ethanol formation over glycerol formation and decreased the glycerol yield in yeast fermentation. Furthermore, alcohol dehydrogenase (ADH) activity dropped significantly from 3.85 to 2.72, 1.83, 0.46, and 0.11 U/mg at 6 h of fermentation at vanillin concentrations of 0, 2.5, 5.0, 10.0, and 25.0 mM correspondingly. In addition, fermentation inhibition by acetic acid and benzoic acid was pH-dependent. Addition of acetate, benzoate, and potassium chloride increased the glucose consumption rate, likely because the salts enhanced membrane permeability, thus increasing glucose consumption

Women and tropical diseases. Introduction

Conversion of chemical signals into mechanical force is very important for implementation of stimuli-responsive hydrogels. We design a core–shell hydrogel capsule that can translate the variations of alcohol concentration into mechanical force. Oil-in-water-in-oil (O/W/O) emulsions are prepared with microfluidic technique and serve as templates for the synthesis of the core–shell capsules. The oil core is ejected from the capsule by the mechanical force generated from the deswelling of the capsule membrane upon increasing the alcohol concentration at a certain temperature below the lower critical solution temperature. The influences of alcohol concentration and temperature on the deswelling process of capsule membranes are investigated systematically. The deswelling rate also plays an important role in the ejection of the oil core. These demonstrations of conversion of alcohol concentration variations into mechanical force provide proof that these core–shell capsules can function as both sensors and actuators of alcohols

Comprehensive Effects of Metal Ions on Responsive Characteristics of P(NIPAM-<i>co</i>-B18C6Am)

Comprehensive investigations of the effects of species and concentrations of metal ions on the ion-responsive behaviors of poly­(<i>N</i>-isopropylacrylamide-<i>co</i>-benzo-18-crown-6-acrylamide) (P­(NIPAM-<i>co</i>-B18C6Am)) are systematically carried out with a series of P­(NIPAM-<i>co</i>-B18C6Am) linear copolymers and cross-linked hydrogels containing different crown ether contents. The results show that when the B18C6Am receptors form stable B18C6Am/M^<i>n</i>+ host–guest complexes with special ions (M^<i>n</i>+), such as K⁺, Sr²⁺, Ba²⁺, Hg²⁺, and Pb²⁺, the LCST of P­(NIPAM-<i>co</i>-B18C6Am) increases due to the repulsion among charged B18C6Am/M^<i>n</i>+ complex groups and the enhancement of hydrophilicity, and the order of the shift degree of LCST of P­(NIPAM-<i>co</i>-B18C6Am) is Pb²⁺ > Ba²⁺ > Sr²⁺ > Hg²⁺ > K⁺. With increasing the content of pendent crown ether groups, the LCST shift degree increases first and then stays unchanged when the B18C6Am content is higher than 20 mol %. Remarkably, it is found for the first time that there exists an optimal ion-responsive concentration for the P­(NIPAM-<i>co</i>-B18C6Am) linear copolymer and cross-linked hydrogel in response to special metal ions, at which concentration the P­(NIPAM-<i>co</i>-B18C6Am) exhibits the most significant ion-responsivity either in the form of linear copolymers or cross-linked hydrogels. With an increase of the content of crown ether groups, the value of corresponding optimal ion-responsive concentration increases. Interestingly, there exists an optimal molar ratio of metal ion to crown ether for the P­(NIPAM-<i>co</i>-B18C6Am) copolymer in response to Pb²⁺, which is around 4.5 (mol/mol). If the ion concentration is too high, the ion-responsive behaviors of P­(NIPAM-<i>co</i>-B18C6Am) may even become surprisingly unobvious. Therefore, to achieve satisfactory ion-responsive characteristics of P­(NIPAM-<i>co</i>-B18C6Am)-based materials, both the operation temperature and the ion concentration should be optimized for the specific ion species. The results in this study provide valuable guidance for designing and applying P­(NIPAM-<i>co</i>-B18C6Am)-based ion-responsive materials in various applications

Wetting-Induced Coalescence of Nanoliter Drops as Microreactors in Microfluidics

Controllable one-to-one coalescence of surfactant-stabilized nanoliter water drops is successfully achieved from wetting-induced drop engulfing in microfluidics by surrounding one of the drops with a thin layer of immiscible wetting fluid. This wetting layer can spread over the other drop to drain away the liquid film between the two drops, thereby inducing coalescence. This innovative approach is totally spontaneous and highly potential in a myriad of fields, such as quantitative analysis, microreaction, and high-throughput injection. To demonstrate this potential, we successfully perform the drop-coalescence-triggered microreaction in microchannels for pH indicator and syntheses of functional materials including micro- and nanoparticles

Additional file 1: of A modified endoscopic submucosal dissection for a superficial hypopharyngeal cancer: a case report and technical discussion

A novel method-Lianjun Di video of ESD procedure, this is video of ESD procedure for the patient. (MP4 88400 kb

Portable Diagnosis Method of Hyperkalemia Using Potassium-Recognizable Poly(<i>N</i>‑isopropylacrylamide-<i>co</i>-benzo-15-crown-5-acrylamide) Copolymers

A novel, simple, portable, and low-cost method for diagnosis of hyperkalemia by using K⁺-recognizable poly­(<i>N</i>-isopropylacrylamide-<i>co</i>-benzo-15-crown-5-acrylamide) [poly­(NIPAM-<i>co</i>-B15C5Am)] linear copolymer as indicator is presented in this work. The pendent 15-crown-5 units in the linear copolymers can selectively and specifically recognize K⁺ to form stable 2:1 “sandwich” host–guest complexes, which cause the copolymer chains to change from the hydrophilic state to the hydrophobic state isothermally, whereas other tested metal ions (e.g., Li⁺, Na⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Cu²⁺, Fe³⁺, Pb²⁺, Cd²⁺, Cr³⁺) cannot be recognized. With increasing the 15-crown-5 content or the K⁺ concentration, the poly­(NIPAM-<i>co</i>-B15C5Am) linear copolymers exhibit higher sensitivity to K⁺. The hyperkalemia can be simply diagnosed by observing the K⁺-induced optical transmittance change of human blood samples with poly­(NIPAM-<i>co</i>-B15C5Am) linear copolymer as an indicator. Normal blood samples with low potassium level containing the poly­(NIPAM-<i>co</i>-B15C5Am) linear copolymer are almost transparent since the copolymer is hydrophilic and soluble at the operating temperature. However, severe hyperkalemia samples with high potassium level become completely cloudy since the copolymer is hydrophobic and insoluble at this temperature. The presented diagnosis method with poly­(NIPAM-<i>co</i>-B15C5Am) linear copolymer as indicator is quite simple and low-cost, and it would bring a new candidate material to design simple and portable tools for diagnosis of hyperkalemia in the general population. Moreover, the results in this work provide valuable guidance for building novel poly­(NIPAM-<i>co</i>-B15C5Am)-based artificial K⁺-recognizable “smart” or “intelligent” systems in various application fields

Conversion of Alcoholic Concentration Variations into Mechanical Force via Core–Shell Capsules

Conversion of chemical signals into mechanical force is very important for implementation of stimuli-responsive hydrogels. We design a core–shell hydrogel capsule that can translate the variations of alcohol concentration into mechanical force. Oil-in-water-in-oil (O/W/O) emulsions are prepared with microfluidic technique and serve as templates for the synthesis of the core–shell capsules. The oil core is ejected from the capsule by the mechanical force generated from the deswelling of the capsule membrane upon increasing the alcohol concentration at a certain temperature below the lower critical solution temperature. The influences of alcohol concentration and temperature on the deswelling process of capsule membranes are investigated systematically. The deswelling rate also plays an important role in the ejection of the oil core. These demonstrations of conversion of alcohol concentration variations into mechanical force provide proof that these core–shell capsules can function as both sensors and actuators of alcohols

Rational Optimization of Bifunctional Organoboron Catalysts for Versatile Polyethers via Ring-Opening Polymerization of Epoxides

Quaternary ammonium and phosphonium borane bifunctional catalysts have shown high catalytic performance in ring-opening polymerization (ROP) of epoxides to produce polyether. Herein, we systematically investigate a series of well-defined organoboron catalysts by varying the electronic and steric properties of the Lewis acidic boron (B) centers, manipulating the steric hindrance on the ammonium cation (N+), adjusting the distance between B and N+, and regulating the nucleic B number of the catalysts. The investigation on the dinuclear catalysts indicated that the reactivity of a given catalyst could be speculated by its B–N–B angle and the B···B distance. We found that the increase of Lewis acidity and the number of B centers of the organoboron catalysts are useful for a high catalytic activity for ROP of epoxides. The Lewis acidity of the B centers was determined using the acceptor numbers, showing an order of borinane (23.4) > BBN (21.7) > BCy2 (18.8) > Bpin (15.5). Moreover, we demonstrated the production of various telechelic polyols in the presence of different chain transfer agents using the organoboron catalysts. The produced telechelic samples have a well-defined terminal functionality with controllable molecular weight. Lastly, these organoboron catalysts were utilized to produce block copolymers, allyl-terminated macromonomers, and random copolymers