Tunable Gas-Gas Reactions through Nanobubble Pathway.

Combustible gas-gas reactions usually do not occur spontaneously upon mixing without ignition or other triggers to lower the activation energy barrier. Nanobubbles, however, could provide such a possibility in solution under ambient conditions due to high inner pressure and catalytic radicals within their boundary layers. Herein, a tunable gas-gas reaction strategy via bulk nanobubble pathway is developed by tuning the interface charge of one type of bulk nanobubble and promoting its fusion and reaction with another, where the reaction-accompanied size and number concentration change of the bulk nanobubbles and the corresponding thermal effect clearly confirm the occurrence of the nanobubble-based H2 /O2 combustion. In addition, abundant radicals can be detected during the reaction, which is considered to be critical to ignite the gas reaction during the fusion of nanobubbles in water at room temperature. Therefore, the nanobubble-based gas-gas reactions provide a safe and efficient pathway to produce energy and synthesize new matter inaccessible under mild or ambient conditions.

Metal organic complexes as an artificial solid-electrolyte interface with Zn-ion transfer promotion for long-life zinc metal batteries.

Metal organic complexes as an artificial solid-electrolyte interface (MOC-SEI) have been generated via in situ coordinative polymerization between Zn2+ and organic ligand molecules. Compared to conventional anodes, the MOC-SEI coated anode significantly prolongs the lifespan from 100 h to 1450 h for the Zn||Zn symmetrical cells and increases the reversible capacity up to 160 mA h g-1 after 1100 cycles for the Zn||V2O5 full-cells.

From dendritic mesoporous silica microspheres to waxberry-like hierarchical hollow carbon spheres: rational design of carbon host for lithium sulfur batteries.

Fabricating sulfur host for the cathode with strong confinement effect and high dispersion of sulfur is vitally important to the development of high-performance lithium sulfur batteries. Benefiting from their unique and tunable structure, good conductivity and chemical inertness, hollow porous carbon materials has been considered as a promising candidate. Herein, precisely designed waxberry-like hierarchical hollow carbon spheres (h-CNS) have been synthesized as the sulfur micro-containers for lithium sulfur batteries. The prepared h-CNS/S electrode shows a good rate capability of 1311 mAh g-1at 0.1 C and 962 mAh g-1at 1 C. In addition, the h-CNS/S electrode also shows satisfactory long cycle performance with 622 mAh g-1at 0.5 C and 400 mAh g-1at 4 C over 600 cycles. The desirable performance can be attributed to the wedge-shape micro-containers which improve the high dispersion of sulfur inside the channels and inhibit the loss of intermediate polysulfide. Moreover, the unique structure can also enhance the transfer of both lithium ions and electrons which benefits to the rate capability of the lithium sulfur batteries.

Estimation of non-constant variance in isothermal titration calorimetry using an ITC measurement model.

Isothermal titration calorimetry (ITC) is the gold standard for accurate measurement of thermodynamic parameters in solution reactions. In the data processing of ITC, the non-constant variance of the heat requires special consideration. The variance function approach has been successfully applied in previous studies, but is found to fail under certain conditions in this work. Here, an explicit ITC measurement model consisting of main thermal effects and error components has been proposed to quantitatively evaluate and predict the non-constant variance of the heat data under various conditions. Monte Carlo simulation shows that the ITC measurement model provides higher accuracy and flexibility than variance function in high c-value reactions or with additional error components, for example, originated from the fluctuation of the concentrations or other properties of the solutions. The experimental design of basic error evaluation is optimized accordingly and verified by both Monte Carlo simulation and experiments. An easy-to-run Python source code is provided to illustrate the establishment of the ITC measurement model and the estimation of heat variances. The accurate and reliable non-constant variance of heat is helpful to the application of weighted least squares regression, the proper evaluation or selection of the reaction model.

Syntheses of high molecular weight hydroxy functional copolymers by green and selective polycondensation methods.

Synthesizing hydroxy-functional linear copolymers with high molecular weights (M n) and low branching degree (Den%) remains challenging, although there has been much headway in the area of functional copolymers. Here, we studied the effect of polymerization methods (one-step or two-step) and solvents (organic solvent: diphenyl ether or ionic liquids: [C n mim]TF2N/BF4/PF6, n = 2, 4, 6, 8, or 10) on M n and Den% of copolymers P(OA-GA) (1,8-octanediol adipate (O-A)/glycerol adipate (G-A)). The M n of P(OA-GA) reached up to 53 937 g mol-1 in two-step in diphenyl ether, and the Den% of glycerol can be controlled within 30%. The physical properties of these copolymers were investigated by contact angles, differential scanning calorimetry (DSC), and in vitro biodegradation. With increasing glycerol content in the polyesters, both hydrophilic properties and degradation properties increased. This system not only facilitates the synthesis of functional polyesters with high molecular weight and low branching, but also expands the possibility of using bio-based monomers to synthesize functional polymers.

The Role of the OH Group in Citric Acid in the Coordination with Fe3O4 Nanoparticles.

The role of the C?OH group in citric acid (CA) in the molecular coordination with Fe3O4 nanoparticles (NPs) has been elusive for a long time. In this study, attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectral deconvolution and thermogravimetric analysis (TGA) have been used to quantitatively clarify its significance in CA adsorption and its corresponding conformation. The experimental results show that the coordination and the corresponding conformation are exclusively determined by COOH not C?OH at pH 3, where its adsorption behavior conforms to the Brunauer?Emmett?Teller (BET) multilayer model with a maximal monolayer coordination number of 2.1/nm2. However, C?OH is involved in the coordination at pH 10, and CA conforms to the Langmuir monolayer model with 1.4/nm2 as its maximal monolayer coordination number, which is more stable than the COOH-only coordination. Especially, the conformational transformation is observed for the first time at pH 3, where the CA molecules adjust their conformation upon elution to maximize the utilization of the available binding sites on Fe3O4 NPs. This finding deepens the understanding on the fundamental mechanism for the interaction between the C?OH and COOH groups containing the organic ligand and metal oxide.

Conformation-Dependent Coordination of Carboxylic Acids with Fe3O4 Nanoparticles Studied by ATR-FTIR Spectral Deconvolution.

The coordination of valeric acid (VA), glutaric acid (GA), and tricarballylic acid (TA) with Fe-OH on the Fe3O4 nanoparticle surface has been systematically studied to elucidate the effects of COOH, molecular configuration, and ligand concentration on the coordination by the combined use of attenuated total reflectance Fourier transform infrared (ATR-FTIR) and thermogravimetric analysis (TGA). The results show that the binding ability of the acids increases with the increase in the COOH number. Multiple conformations coexist for the dicarboxylic and tricarboxylic acid coordinated on the iron oxide NPs. Saturated coordination formed with only a one-, two-, or three-COOH conformation for VA, GA, and TA, respectively, occurs under ligand-scarce conditions, while unsaturated coordination formed with the mixture of uncoordinated, one-, and/or two-COOH conformations for VA, GA, and TA, respectively, exists under ligand-abundant conditions. The maximum coordination numbers for monolayer adsorption for VA, GA, and TA on Fe3O4 NPs are 9, 2.4, and 2.7 nm-2, respectively. This study helps us to understand the fine coordination mechanism caused by the acid molecules with different configurations and elucidates, for the first time, the fine conformational variance incurred by the surrounding ligand with different concentrations and the way in which the ligand is added.

Synergetic Determination of Thermodynamic and Kinetic Signatures Using Isothermal Titration Calorimetry: A Full-Curve-Fitting Approach.

Thermodynamic and kinetic signatures are pivotal information for revealing the binding mechanisms of biomolecules, and they play an indispensable role in drug discovery and optimization. While noncalorimetric methods measure only a part of these signatures, isothermal titration calorimetry (ITC) is considered to have the potential to acquire full signatures in an experiment. However, kinetic parameters are generally difficult to extract from ITC curves, as they are inevitably affected by the instrument-response function and the collateral heat of associated process during titrations. Thus, we herein report the development and validation of a full-curve-fitting method to resolve thermal power curves and to maximize the signal extraction using ITC. This method is then employed to quantify the dilution of an aqueous n-propanol solution and examine the inhibition of carbonic anhydrase by 4-carboxybenzenesulfonamide using a commercial instrument with a long apparent response time of ∼13 s.

Alloyed Crystalline Au-Ag Hollow Nanostructures with High Chemical Stability and Catalytic Performance.

For bimetallic nanoparticles (NPs), the degree of alloying is beginning to be recognized as a significant factor affecting the NP properties. Here, we report an alloyed crystalline Au-Ag hollow nanostructure that exhibits a high catalytic performance, as well as structural and chemical stability. The Au-Ag alloyed hollow and porous nanoshell structures (HPNSs) with different morphologies and subnanoscale crystalline structures were synthesized by adjusting the size of the sacrificial Ag NPs via a galvanic replacement reaction. The catalytic activities of the nanomaterials were evaluated by the model reaction of the catalytic reduction of p-nitrophenol by NaBH4 to p-aminophenol. The experimental results show that the subnanoscale crystalline structure of the Au-Ag bimetallic HPNSs has much greater significance than the apparent morphology does in determining the catalytic ability of the nanostructures. The Au-Ag alloyed HPNSs with better surface crystalline alloying microstructures and open morphologies were found to exhibit much higher catalytic reaction rates and better cyclic usage efficiencies, probably because of the better dispersion of active Au atoms within these materials. These galvanic replacement-synthesized alloyed Au-Ag HPNSs, fabricated by a facile method that avoids Ag degradation, have potential applications in catalysis, nanomedicine (especially in drug/gene delivery and cancer theranostics), and biosensing.

Novel top-contact monolayer pentacene-based thin-film transistor for ammonia gas detection.

We report on the fabrication of an organic field-effect transistor (OFET) of a monolayer pentacene thin film with top-contact electrodes for the aim of ammonia (NH3) gas detection by monitoring changes in its drain current. A top-contact configuration, in which source and drain electrodes on a flexible stamp [poly(dimethylsiloxane)] were directly contacted with the monolayer pentacene film, was applied to maintain pentacene arrangement ordering and enhance the monolayer OFET detection performance. After exposure to NH3 gas, the carrier mobility at the monolayer OFET channel decreased down to one-third of its original value, leading to a several orders of magnitude decrease in the drain current, which tremendously enhanced the gas detection sensitivity. This sensitivity enhancement to a limit of the 10 ppm level was attributed to an increase of charge trapping in the carrier channel, and the amount of trapped states was experimentally evaluated by the threshold voltage shift induced by the absorbed NH3 molecular analyte. In contrast, a conventional device with a 50-nm-thick pentacene layer displayed much higher mobility but lower response to NH3 gas, arising from the impediment of analyte penetrating into the conductive channel, owing to the thick pentacene film.

[The origin and development of special methods of "expiration and inspiration" (Tuna) in pre-Qin and Han dynasties].

Tuna (special methods of expiration and inspiration) was generated in the working life and health activities of the early stage of the human race in ancient times. It developed in the period of the Qin, Han and three kingdoms, developing the theory of bionic expiration and inspiration as well as the breath of the upper pubic region (Dantian); the skill of the Qi conduction school emerged so that the skills of embryonic breath and the upper pubic region breath came into being. The skill of meditation of the Chan sect of the Western Regions was also introduced into the central plains at this time. The skill of counting breath had a profound impact on the skill of embryonic breath of the Taoism elixir school.

First-Principles Study of the Band Gap Structure of Oxygen-Passivated Silicon Nanonets.

A net-like nanostructure of silicon named silicon nanonet was designed and oxygen atoms were used to passivate the dangling bonds. First-principles calculation based on density functional theory with the generalized gradient approximation (GGA) were carried out to investigate the energy band gap structure of this special structure. The calculation results show that the indirect-direct band gap transition occurs when the nanonets are properly designed. This band gap transition is dominated by the passivation bonds, porosities as well as pore array distributions. It is also proved that Si-O-Si is an effective passivation bond which can change the band gap structure of the nanonets. These results provide another way to achieve a practical silicon-based light source.

[Research on developmental characteristic of the theory of ZANG-fu differentiation of syndromes in the period of Jin-Tang Dynasties.].

In the period from Jin to Tang dynasties, the Theory of Zang-fu differentiation of syndromes had been set up and prosperous. During this period, the first summary of the theory appeared, and the eight principles of Zang-fu differentiation, pulse diagnosis combining with Zang-fu theory upgraded to a new higher level, the application of medicines and prescriptions perfected. This theory was completely diffused into clinical practice. Since Taoism specifically stressed the theory of Zang-fu differentiation of syndromes, this theory expanded its influence and promoted its development.

[Studies on developmental features of theories of syndrome differentiation of zang-fu viscera in Qin and Han Dynasties].

The formation of the theories of visceral manifestations as well as channels and collaterals in the books Huangdi Neijing (Inner Canon of Huangdi) and Nan Jing (Classic of Questioning) laid down the theoretical foundation for the theories of syndrome differentiation of zang--fu viscera. From the early occurrence of syndrome classification to that of the disease manifestations of zang and fu viscera, the theories of syndrome differentiation of zang--fu viscera were basically not put into practice until Shanghan Zabing Lun (Treatise on Cold Pathogenic and Miscellaneous Diseases) appeared. The theories of syndrome differentiation of zang--fu viscera in the Qin and Han Dynasties were not systematic and were scattered, indicating that it was a period of gestation for the theories.

[Effects of local carbon ion irradiation on survival and peripheral blood leukocyte and platelet counts of tumor-bearing mice].

OBJECTIVE: To investigate the effects of local carbon ion irradiation on the length of survival and peripheral blood leukocyte and platelet counts of mice inoculated with pulmonary tumor cells. METHODS: Thirty tumor-bearing mice were randomly divided into control group (tumor-bearing but without carbon ion irradiation, n=10), 12 Gy group (n=10) and 24 Gy group (n=10). The right hind limbs of the mice, where the tumor cells were inoculated, were irradiated with carbon-ion beams at a single dose in 12 Gy and 24 Gy groups, and those of the control group received no irradiation. The peripheral blood leukocytes and platelets of the mice in all the 3 groups were counted immediately before and 7 and 14 days after irradiation, respectively, with the survival time of the mice recorded. RESULTS: There was no significant difference in the survival time of the mice between the 3 groups. The peripheral blood leukocyte counts in all groups increased after irradiation, no significant difference was noted between the two irradiation the groups and the control group. Irradiation at 24 Gy resulted in significant increase in peripheral blood platelet count on the 14th day (P=0.032, F=4.062), but no such increment was observed in the other 2 groups or on day 7 in the 24 Gy group. CONCLUSION: Local carbon ion irradiation may not produce significant effects on the length of survival and hemogram of the tumor-bearing mice.