Trade agreements and CO2 emissions in Asian countries: accounting for institutional heterogeneity.

This paper aims to measure the impact of environmental provisions in free-trade agreements on pollution levels in 40 Asian economies for the period 1990-2019. Following the failure of WTO negotiations, there has been a rapid proliferation of preferential trade agreements incorporating various types of environmental clauses. We exploit such changes to assess their influence on pollution emissions. We use a DOLS approach that considers the potential endogeneity of environmental clauses. Further, panel vector error correction models (VECM) are employed for examining the presence of a cointegration relationship among the variables studied. Overall, our findings indicate that these environmental clauses have heterogenous effects on CO2 emissions. We do not find significant effects of environmental clauses on pollution. However, this result is driven by environmental provisions that are not legally enforceable. We do find a positive effect of environmental clauses with a higher level of legalism on the environmental quality. These results show that the inclusion of environmental provisions in trade agreements is not sufficient by itself. Such provisions should incorporate a legally enforceable framework to effectively address environmental concerns. These findings have significant policy implications for Asian countries.

Exploration of high-performance triptycene-based thermally activated delayed fluorescence materials via structural alteration of donor fragment.

The utilization of thermally activated delayed fluorescence (TADF) materials in highly proficient organic light-emitting diodes (OLEDs) has attracted much attention. Based on TADF material TPA-QNX(CN)2, a series of three-dimensional donor-acceptor (D-A) triptycenes have been designed via structural modification of D-fragment. The influences of different D-fragments with various electron-donating strengths on the singlet-triplet energy gap (ΔEST), emission wavelength (λem), and electron/hole reorganization energy (λe/λh) are extensively studied by applying density functional theory (DFT) coupled with time-dependent density functional theory (TD-DFT). The computed results imply that as the electron-donating strength of the D-fragments increases, the ΔEST value decreases and λem is red-shifted for the molecules using the same acceptor units. Analogously, the 1CT‒3CT state splitting (ΔEST (CT)) is also decreased by enlarging the twist angle (ß) between the phenyl ring and alternative D-fragment. Therefore, efficient color tuning within a broad emission range (434-610 nm), as well as small ΔEST (CT) values (0.01-0.05 eV), has been accomplished by structural modification of the D-fragments. The greater electron-donating strength, the smaller ΔEST, and the smaller λh for PPXZ-QNX(CN)2 make it the best candidate among all the designed molecules.

Exploring the Influence of Engineering the Linker between the Donor and Acceptor Fragments on Thermally Activated Delayed Fluorescence Characteristics.

We have expounded the unique molecular design architecture for efficient thermally activated delayed fluorescence (TADF) materials based on a donor-linker-acceptor-linker-donor (D-L-A-L-D) framework, which can be employed as predecessors of organic light-emitting diode (OLED) devices. Different from traditional donor-acceptor-type (D-A-type) TADF scaffolds, the D-L-A-L-D structural design avoids direct coupling amid the D and A fragments allowing the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) to be spatially separated. It results in a reduced overlap between HOMOs and LUMOs, thus realizing fairly a slight singlet-triplet energy gap (ΔE ST) and higher photoluminescence quantum yield (Φ). We revealed that manipulating a linker between D and A fragments in intramolecular charge transfer compounds is an auspicious approach for realizing small ΔE ST. Herein, we report a group of organic electroluminescent D-L-A-L-D-type molecules with different electron-donating and electron-accepting moieties using density functional theory calculations and time-dependent density functional theory calculations. Two types of linkers, the π-conjugated phenylene (-C6H4-) and aliphatic alkyl chains or σ-spacer (-CH2- and -CH2-CH2-), were exploited between D and A fragments. In principle, the conjugation in D-π-A-π-D-type molecules and hyperconjugation in D-σ-A-σ-D type molecules encourage the spatial separation of the HOMO-LUMO causing a reduction in the ΔE ST. All the designed molecules show a blue-shift in the emission wavelengths (λem) over the directly linked parent molecules except DPA-DPS-C6H4 and BTPA-DPS-C6H4 which show a red-shift. Violet-blue to green-yellow (376-566 nm) λem was observed from all of the investigated molecules. Other important properties that affect the efficiency of emission quantum yields like frontier molecular orbital analysis, natural population analysis, electron excitation analysis, exciton binding energies, ionization potentials, electronic affinities, and reorganization energies of the designed molecules were also inspected. We are confident that our work will effectively give a straightforward and distinctive approach to building incredibly effective TADF-OLEDs and a new perspective on their structural design.

Correction to: Synthesis of a three-dimensional interconnected carbon nanorod aerogel from wax gourd for amperometric sensing.

The published version of this article, unfortunately, contains error. The authors regret that one typo was present in the first author name "Cuxing Xu" when it should be "Cuixing Xu".

Low-cost and environment-friendly synthesis of carbon nanorods assembled hierarchical meso-macroporous carbons networks aerogels from natural apples for the electrochemical determination of ascorbic acid and hydrogen peroxide.

In this work, the low-cost carbon nanorods assembled hierarchical meso-macroporous carbons networks aerogels (CNs-HMCNAs) was environment-friendly synthesized from a cheap and abundant biomass of apples (Malus pumila Mill) for the first time. The biomass of apples derived CNs-HMCNAs exhibited the unique hierarchical meso-macroporous structure with large specific surface area and high density of edge defective sites. At the CNs-HMCNAs modified GCE (CNs-HMCNAs/GCE), the electron transfer between the glassy carbon electrode (GCE) and the ascorbic acid (AA) (or hydrogen peroxide (H2O2)) was effectively enhanced, and thus induced a low overvoltage for AA electrooxidation (or H2O2 electroreduction). As an electrochemical AA (or H2O2) sensor, the CNs-HMCNAs/GCE exhibited wider linear range, lower detection limit, higher sensitivity and stability than GCE and the carbon nanotubes modified GCE (CNTs/GCE). In particular, the CNs-HMCNAs/GCE showed great potential feasibility in the practical determination of AA (in AA injection, Vitamin C tablet and kiwi juice) or H2O2 (in human urine, milk and beer).

Synthesis of a three-dimensional interconnected carbon nanorod aerogel from wax gourd for amperometric sensing.

The authors describe a method for synthesis of a three-dimensional (3D) interconnected carbon nanorod aerogel (3D-ICNA) starting from wax gourd (Benincasa hispida) which is a low-cost biomass. The 3D-ICNA possesses unique 3D interconnected and porous nanostructure, with abundant edge-plane-like defective sites, a large specific surface area (823 m2 g-1) and a large pore volume (0.12 cm3 g-1). This makes the material attractive in terms of electrochemical sensing. To validate the feasibility, the voltammetric response towards ferricyanide, hydrogen peroxide (H2O2), acetaminophen, ascorbic acid (AA), dopamine, uric acid and epinephrine was investigated by using a glassy carbon electrode (GCE) modified with 3D-ICNA. The modified GCE shows higher electron-transfer capacity than a conventional GCE. In addition, as an electrochemical sensor for AA or H2O2, the electrode exhibits better analytical performance with lower detection limit [3.5 µM for AA or 0.68 µM for H2O2 based on 3σ/m criterion (where σ is the standard deviation of the blank and m is the slope of the calibration plot)], wider linear range and higher sensitivity (0.14, 0.11 and 0.080 µA µM-1 cm-2 for AA or 0.24 and 0.20 µA µM-1 cm-2 for H2O2) compared to a plain GCE or a carbon nanotube-modified GCE. The modified GCE exhibits a large potential for the amperometric determination of AA or H2O2 in real samples. Graphical abstract By employing the biomass of wax gourd (Benincasa hispida) as the precursor, a three-dimensional interconnected carbon nanorod aerogel was prepared. It is shown to be a viable material for the construction of an advanced electrochemical sensor for H2O2 and ascorbic acid.

Sensitive nonenzymatic detection of hydrogen peroxide at nitrogen-doped graphene supported-CoFe nanoparticles.

In this work, a new enzymeless sensor for hydrogen peroxide (H2O2) was constructed by supporting CoFe nanoparticles on the nitrogen-doped graphene (CoFe/NGR). In this preparation, the graphene oxide (GO) is first used as substrate for the growth of CoFe layered double hydroxides (CoFe LDHs) through hydrothermal reaction. Then, the pyrolysis of CoFe LDHs/GO under NH3 produces CoFe/NGR. By supporting CoFe nanoparticles on NGR support, the electrocatalytic performance of CoFe is dramatically improved because of high electric conductivity of NGR. Consequently, the combination of CoFe and NGR allows the nonenzymatic detection of H2O2. Compared with the unsupported CoFe nanoparticles, the CoFe/NGR displays high electrocatalytic activity towards H2O2, enabling a high sensitivity of 435.7 µA mM-1 cm-2 and low detection limit of 0.28 µM towards the reduction of H2O2. Especially, the attractive feature of low cost and outstanding analytical performance of CoFe/NGR suggest it great potential in electrochemical sensor and biosensor fabrication.

Cost-effective synthesis of three-dimensional nitrogen-doped nanostructured carbons with hierarchical architectures from the biomass of sea-tangle for the amperometric determination of ascorbic acid.

In this work, the three-dimensional nitrogen-doped nanostructured carbons with hierarchical architectures (3D-NNCsHAs) with high density of defective sites, high surface area and pluralities of pore size distributions was prepared through the pyrolysis of sea-tangle (Laminaria japonica), an inexpensive, eco-friendly and abundant precursor. Benefitting from their structural uniqueness, a selective and sensitive ascorbic acid (AA) sensor based on 3D-NNCsHAs was developed. Compared to the glassy carbon electrode (GCE) and the carbon nanotubes modified GCE (CNTs/GCE), the 3D-NNCsHAs modified GCE (3D-NNCsHAs/GCE) presents higher performance towards the electrocatalysis and detection of AA, such as lower detection limit (1 µM), wider linear range (10-4410 µM) and lower electrooxidation peak potential (-0.02 V vs. Ag/AgCl). In addition, 3D-NNCsHAs/GCE also exhibits high anti-interference and anti-fouling abilities for AA detection. Particularly, the fabricated 3D-NNCsHAs/GCE is able to determine AA in real samples and the results acquired are satisfactory. Therefore, the 3D-NNCsHAs can be considered as a kind of novel electrode nanomaterial for the fabrication of selective and sensitive AA sensor for the extensive practical applications ranging from food analysis, to pharmaceutical industry and clinical test.

Pt nanoparticles supported on nitrogen-doped porous graphene for sensitive detection of Tadalafil.

Graphene (GR) is one of the most promising candidates for utilization in the electroanalytical field because of its superior electrocatalytic activity, excellent electronic conductivity, and high chemical stability. However, the GR sheets usually tend to stack together with π-π interaction. The spontaneous stacking leads to the aggregation of the GR sheets and imposes a negative feedback in the surface area of the GR, which obviously limits its electrochemical application. In this study, nitrogen-doped porous GR (NPGR) with different pore sizes is prepared by using silica (SiO2) as a template. The NPGR exhibits high surface area and porous structure, fulfilling the requirement for supporting materials. Being a support, the structural uniqueness and N dopants of NPGR facilitate the deposition of Pt nanoparticles (Pt NPs). The Pt NPs/NPGR composites integrate the structural properties of NPGR and catalytic properties of Pt NPs. A selective and sensitive electrochemical sensor was successfully developed for sensitive determination of Tadalafil (TAD), showing a concentration range of 1.30-488.9µM and limit of detection of 0.268µM.

Cobalt nanoparticles/nitrogen-doped graphene with high nitrogen doping efficiency as noble metal-free electrocatalysts for oxygen reduction reaction.

Nitrogen-doped graphene (N/GR) has been considered as active metal-free electrocatalysts for oxygen reduction reaction (ORR). However, the nitrogen (N) doping efficiency is very low and only few N atoms are doped into the framework of GR. To boost the N doping efficiency, in this work, a confined pyrolysis method with high N doping efficiency is used for the preparation of cobalt nanoparticles/nitrogen-doped GR (Co/N/GR). Under the protection of SiO2, the inorganic ligand NH3 in cobalt amine complex ([Co(NH3)6]3+) is trapped in the confined space and then can be effectively doped into the framework of GR without the introduction of any carbon residues. Meanwhile, due to the redox reaction between the cobalt ions and carbon atoms of GR, Co nanoparticles are supported into the framework of N/GR. Due to prevention of GR layer aggregation with SiO2, the Co/N/GR with high dispersion provides sufficient surface area and maximum opportunity for the exposure of Co nanoparticles and active sites of N dopant. By combination of enhanced N doping efficiency, Co nanoparticles and high dispersion of GR sheets, the Co/N/GR is remarkably active, cheap and selective noble-metal free catalysts for ORR.

Kikuchi-fujimoto disease: diagnostic dilemma and the role of immunohistochemistry.

UNLABELLED: Kikuchi-Fujimoto (KD) disease is the rare differential diagnoses of chronic cervical lymphadenopathy of unknown etiology. The findings of histopathology may be overlapping, in such condition immunohistochemistry has a definite role to play. Since Tubercular lymphadenopathy is the commonest cause for chronic cervical lymphadenopathy in developing and tropical country like India. Occasionally it is misdiagnosed, ignoring the other rare condition like KD if immunohistochemistry is not taken into consideration to differentiate. As a result the morbidity increases and cost of antitubercular treatment (ATT) in wrong diagnosed case is enormous. We report a similar case of misdiagnoses, non responsive to ATT, finally diagnosed as a case of Kikuchi-Fujimoto disease, did well after recommended treatment. KEYWORDS: Necrotizing lymphadenitis; Chronic cervical lymphadenitis; Immunohistochemistry.