Rectangular 3-snip punctoplasty versus punch punctoplasty with silicone intubation for acquired external punctal stenosis: a prospective randomized comparative study

Xuan Liao. Department of Ophthalmology, Affiliated Hospital of North Sichuan Medical College, 1 Mao Yuan Nan Road, Nanchong 637000, Sichuan, China. aleexand@163.com     

Patterned nanofiber air filters with high optical transparency,robust mechanical strength,and effective PM2.5 capture capability

PM_2.5, due to its small particle size, strong activity, ease of the attachment of toxic substances and long residence time in the atmosphere, has a great impact on human health and daily production. In this work, we have presented patterned nanofiber air filters with high optical transparency, robust mechanical strength and effective PM_2.5 capture capability. Here, to fabricate a transparency air filter by a facile electrospinning method, we chose three kinds of patterned wire meshes with micro-structures as negative receiver substrates and directly electrospun polymer fibers onto the supporting meshes. Compared with randomly oriented nanofibers (named “RO NFs” in this paper) and commercially available facemasks, the patterned air filters showed great mechanical properties, and the water contact angles on their surfaces were about 122–143° (the water contact angle for RO NFs was 81°). In addition, the patterned nanofibers exhibited high porosity (>80%), and their mean pore size was about 0.5838–0.8686 μm (the mean pore size of RO NFs was 0.4374 μm). The results indicate that the transparent patterned air filters have the best PM_2.5 filtration efficiency of 99.99% at a high transmittance of ∼69% under simulated haze pollution.

PM_2.5, due to its small particle size, strong activity, ease of the attachment of toxic substances and long residence time in the atmosphere, has a great impact on human health and daily production.     

pH-Dependent transfer hydrogenation or dihydrogen release catalyzed by a [(η6-arene)RuCl(κ2-N,N-dmobpy)]+ complex: a DFT mechanistic understanding

The reaction mechanism of the pH-dependent transfer hydrogenation of a ketone or the dehydrogenation of formic acid catalyzed by a [(η⁶-arene)RuCl(κ²-N,N-dmobpy)]⁺ complex in aqueous media has been investigated using the density functional theory (DFT) method. The TM-catalyzed TH of ketones with formic acid as the hydrogen source proceeds via two steps: the formation of a metal hydride and the transfer of the hydride to the substrate ketone. The calculated results show that ruthenium hydride formation is the rate-determining step. This proceeds via an ion-pair mechanism with an energy barrier of 14.1 kcal mol⁻¹. Interestingly, the dihydrogen release process of formic acid and the hydride transfer process that produces alcohols are competitive under different pH environments. The investigation explores the feasibility of the two pathways under different pH environments. Under acidic conditions (pH = 4), the free energy barrier of the dihydrogen release pathway is 4.5 kcal mol⁻¹ that is higher than that of the hydride transfer pathway, suggesting that the hydride transfer pathway is more favorable than the dihydrogen release pathway. However, under strongly acidic conditions, the dihydrogen release pathway is more favorable compared to the hydride transfer pathway. In addition, the ruthenium hydride formation pathway is less favorable than the ruthenium hydroxo complex formation pathway under basic conditions.

A DFT mechanistic study has been performed to unveil the nature of preference of transfer hydrogenation of ketones and dihydrogen release catalyzed by single-site cyclometallated ruthenium complexes under different pH environments.     

MOF-derived ZnCo2O4 porous micro-rice with enhanced electro-catalytic activity for the oxygen evolution reaction and glucose oxidation

A porous ZnCo₂O₄ micro-rice like microstructure was synthesized via calcination of a Zn–Co MOF precursor at an appropriate temperature. The as-prepared ZnCo₂O₄ sample presented good electrocatalytic oxygen evolution reaction performance with a small overpotential (η₁₀ = 389 mV) and high stability in basic electrolyte. Furthermore, in basic medium, the as-synthesized ZnCo₂O₄ micro-rice also showed good electrocatalytic activity for glucose oxidation. A ZnCo₂O₄ micro-rice modified glass carbon electrode may be used as a potential non-enzymatic glucose sensor. The excellent electrocatalytic OER and glucose oxidation performances of ZnCo₂O₄ might be attributed to the unique porous structure formed by the nanoparticles. The porous architecture of the micro-rice can provide a large number of electrocatalytically active sites and high electrochemical surface area (ECSA). The result may offer a new way to prepare low-cost and high performance oxygen evolution reaction and glucose oxidation electrocatalysts.

A porous ZnCo₂O₄ micro-rice like microstructure was synthesized via calcination of a Zn–Co MOF precursor at an appropriate temperature.     

Synthesis of a fine LiNi0.88Co0.09Al0.03O2 cathode material for lithium-ion batteries via a solvothermal route and its improved high-temperature cyclic performance

Nickel–Cobalt–Aluminum (NCA) cathode materials for lithium-ion batteries (LIBs) are conventionally synthesized by chemical co-precipitation. However, the co-precipitation of Ni²⁺, Co²⁺, and Al³⁺ is difficult to control because the three ions have different solubility product constants. This study proposes a new synthetic route of NCA, which allows fabrication of fine and well-constructed NCA cathode materials by a high temperature solid-state reaction assisted by a fast solvothermal process. The capacity of the LiNi_0.88Co_0.09Al_0.03O₂ as-synthesized by the solvothermal method was 154.6 mA h g⁻¹ at 55 °C after 100 cycles, corresponding to 75.93% retention. In comparison, NCA prepared by the co-precipitation method delivered only 130.3 mA h g⁻¹ after 100 cycles, with a retention of 63.31%. Therefore, the fast solvothermal process-assisted high temperature solid-state method is a promising candidate for synthesizing high-performance NCA cathode materials.

Nickel–Cobalt–Aluminum (NCA) cathode materials for lithium-ion batteries (LIBs) are conventionally synthesized by chemical co-precipitation.     

Preparation of environmentally friendly acrylic pressure-sensitive adhesives by bulk photopolymerization and their performance

Polyacrylic pressure-sensitive adhesives (PSAs) based on butyl acrylate (BA), 2-hydroxyethyl acrylate (HEA), and acrylic acid (AA) were prepared by a bulk polymerization process triggered by a radical photoinitiator under UV irradiation and UV-crosslinking. 1,6-Hexanediol diacrylate (HDDA) with difunctional groups was introduced into the PSAs to modify semi-interpenetrating network structures. The effect of HDDA content on the pressure-sensitive performance was comprehensively tested. The viscosity of the prepolymer was measured by a rotational viscometer. Prepolymers obtained by a photoinduced process and UV crosslinking process were confirmed via Fourier transform infrared spectroscopy (FTIR). All double bonds participated in the copolymerization without any remaining monomers, which reflected the concept of green environmental protection. Gel content in the crosslinked portion was examined by Soxhlet extraction, whilst the soluble molecular weight of PSAs was characterized by gel permeation chromatography (GPC). The viscoelastic properties of polymer films were determined by dynamic mechanical analysis (DMA). The T_g value and storage modulus (G′) of the PSAs were enhanced with the addition of HDDA. Moreover, three fundamental adhesive properties, i.e. loop tack force, peel force and shear strength of PSAs, were measured. The results showed that UV crosslinking technology achieved a good balance of the three forces with excellent pressure-sensitive properties.

Polyacrylic pressure-sensitive adhesives based on butyl acrylate, 2-hydroxyethyl acrylate, and acrylic acid were prepared by a bulk polymerization process triggered by a radical photoinitiator under UV irradiation and UV-crosslinking.     

Intrinsic defect engineered Janus MoSSe sheet as a promising photocatalyst for water splitting

The Janus MoSSe sheet has aroused significant attention due to its band edge position and intrinsic dipole moment, making it a strong candidate for water splitting photocatalysis. However, weak water adsorption seriously prevents its further application. Here, first-principles calculations are used to explore the effect of intrinsic defects on water adsorption and conversion at the Janus MoSSe sheet. First-principles calculation results clearly show that intrinsic defects (S_vac, Mo_anti, and Mo_int) can effectively alter the interaction between water and the MoSSe sheet. Except for S_vac defects, the adsorption energy of water at Mo_anti or Mo_int defects can be significantly increased by −1.0 to −1.5 eV with respect to the weak water adsorption on a pristine MoSSe sheet of about −0.24 eV. More importantly, the energy barrier for water conversion can be dramatically lowered by 48% to 0.7 eV at Mo_anti or Mo_int defects, together with a more stable final state. Such significant enhancement of the adsorption energy is attributed to the red shift of water energy levels, resulting from the strong interaction between O2p orbitals and Mo3d orbitals. It is shown that the intrinsic defects have the potential to change the photocatalytic reactivity of the surface, and thus this may serve as an important way to design photocatalysts for water splitting.

The Janus MoSSe sheet has aroused significant attention due to its band edge position and intrinsic dipole moment, making it a strong candidate for water splitting photocatalysis.     

The characterization and evaluation of the synthesis of large-ring cyclodextrins (CD9–CD22) and α-tocopherol with enhanced thermal stability

Large-ring cyclodextrins LR-CDs (CD₉–CD₂₂) were obtained from rice starch using cyclodextrin glycosyltransferase (CGTase), and were used as a wall material for embedding α-tocopherol. Complexes of α-tocopherol and LR-CDs were prepared by co-precipitation. A molar ratio of α-tocopherol/LR-CD of 1 : 2 showed the highest encapsulation efficiency. The surface morphology of the complex particles was observed to vary from irregular flakes to the formation of smaller clusters of particles using scanning electron microscopy (SEM). Based on ¹H NMR and FT-IR observations, the inclusion complexes exhibited significant chemical shifts of 0.3 ppm and decreased peak signals. In addition, thermal analysis showed that the microcapsules improved the thermostability of the α-tocopherols. Antioxidant activity analysis proved the stability of α-tocopherol during storage. This study could serve as a reference for the more effective use of LR-CDs as wall materials.

Large-ring cyclodextrins LR-CDs (CD₉–CD₂₂) were obtained from rice starch using cyclodextrin glycosyltransferase (CGTase), and were used as a wall material for embedding α-tocopherol.     

Heavy metal adsorption using structurally preorganized adsorbent

Heavy metal pollution is an essential environmental issue in the world. The current methods present limitations for the removal of low concentration divalent heavy metals from wastewater, such as high cost, unsatisfactory adsorption capacity, and poor reusability. Herein, we designed and prepared a novel chelating adsorbent. The adsorbent was prepared using chloromethyl polystyrene microsphere as a framework material modified by ethylenediaminetetraacetic acid (EDTA) with two types of functional groups and six binding sites in one coordination unit. Each coordination unit of the adsorbent prepared provides two negative charges of two carboxyl groups to balance the two positive charges of the divalent heavy metal ion, and forms coordination bonds through its two nitrogen atoms and two amidic carbonyl groups. This synergistic adsorption effect produced by electrostatic interaction and chelation significantly improves the adsorption capacity. The adsorption of some environmental heavy metals was tested, and high adsorption capacity for Pb(ii) was obtained. The saturated adsorption capacity for Pb(ii) was as high as 352.1 mg g⁻¹, and the effluent concentration of the column experiment was less than 0.20 ppm. Simultaneously, the presence of the amide group shows good anti-interference to alkali metals and alkali soil metals. The result is of considerable significance to the actual wastewater treatment.

The adsorbent had two types of functional groups and six binding sites in one coordination unit. The presence of the amide group shows good anti-interference to alkali metals and alkali soil metals.     

A thermal energy storage composite by incorporating microencapsulated phase change material into wood

Phase change energy storage wood (PCESW) was prepared by using microencapsulated phase change materials (MicroPCM) as thermal energy storage (TES) materials and wood as the matrix. The incorporation of MicroPCM and wood was realized using a vacuum impregnation method. The morphology and microstructure of MicroPCM, delignified wood (DLW) and PCESW were observed by scanning electron microscopy (SEM); the thermal properties including phase change temperature, enthalpy, thermal stability, thermal conductivity of MicroPCM and PCESW were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and laser flash analysis (LFA). The results showed that: (1) delignification improved the porosity of wood and enhanced the impregnation effect, MicroPCM got into the delignified wood successfully and mainly distributed in the vessels; (2) PCESW had excellent energy storage capacity and suitable phase transition temperature for regulating indoor temperature; (3) PCESW had prior thermal stability at room temperature and great durability after 100 heating–cooling cycles; (4) addition of graphene greatly improved the thermal conductivity of PCESW. The TES composite can be used as an indoor temperature regulating material for building energy conservation.

Phase change energy storage wood (PCESW) was prepared by using microencapsulated phase change materials (MicroPCM) as thermal energy storage (TES) materials and wood as the matrix.