Identification macrophage signatures in prostate cancer by single-cell sequencing and machine learning.

BACKGROUND: The tumor microenvironment (TME) encompasses a variety of cells that influence immune responses and tumor growth, with tumor-associated macrophages (TAM) being a crucial component of the TME. TAM can guide prostate cancer in different directions in response to various external stimuli. METHODS: First, we downloaded prostate cancer single-cell sequencing data and second-generation sequencing data from multiple public databases. From these data, we identified characteristic genes associated with TAM clusters. We then employed machine learning techniques to select the most accurate TAM gene set and developed a TAM-related risk label for prostate cancer. We analyzed the tumor-relatedness of the TAM-related risk label and different risk groups within the population. Finally, we validated the accuracy of the prognostic label using single-cell sequencing data, qPCR, and WB assays, among other methods. RESULTS: In this study, the TAM_2 cell cluster has been identified as promoting the progression of prostate cancer, possibly representing M2 macrophages. The 9 TAM feature genes selected through ten machine learning methods and demonstrated their effectiveness in predicting the progression of prostate cancer patients. Additionally, we have linked these TAM feature genes to clinical pathological characteristics, allowing us to construct a nomogram. This nomogram provides clinical practitioners with a quantitative tool for assessing the prognosis of prostate cancer patients. CONCLUSION: This study has analyzed the potential relationship between TAM and PCa and established a TAM-related prognostic model. It holds promise as a valuable tool for the management and treatment of PCa patients.

Prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae among healthy children under 5 years of age in Hainan Province, China.

BACKGROUND: The thirteen-valent pneumococcal conjugate vaccine (PCV13) is not included in the national immunization program and is administered voluntarily with informed consent in China. In preparation for assessing the impact of pilot introduction in Hainan Province, we conducted a carriage study among children under 5 years of age from four locations in Hainan Province, China. METHODS: From March to June 2022, nasopharyngeal (NP) swabs, collected from healthy children aged younger than 59 months who lived in the 4 different locations (Haikou, Wanning, Baisha and Qiongzhong) in Hainan Province, were tested for pneumococcus using conventional culture. Pneumococcal isolates were serotyped using the Quellung reaction. Risk factors associated with pneumococcal colonization were assessed using univariate analysis and multivariable logistic regression adjusting for age, daycare attendance and other factors. RESULTS: Pneumococcus was isolated in 710 (30.4%) of the 2333 children enrolled. Of 737 pneumococci, 29 serotypes were identified; 60.9% were PCV13 serotypes; the most common vaccine serotypes were 6B (20.4%), 19F (13.0%), 6A (11.9%) and 23F (6.1%); and the most common nonvaccine serotypes were 23A (12.9%), 34 (6.1%) and nontypeable (NT) pneumococci (5.6%). Children vaccinated with PCV13 had lower carriage (17.7% vs 32.5%; P = 0.0001) and fewer PCV13 serotypes (41.9% vs 62.7%; P = 0.0017) compared to unimmunized children. After adjustment, NP carriage was higher among children attending daycare (aOR = 2.3, 95% CI: 1.7-3.2), living in rural areas (aOR = 1.4, 95% CI: 1.1-1.8), living with siblings (aOR = 1.3, 95% CI: 1.0-1.6) and whose mothers had completed senior high/technical secondary school (aOR = 1.5, 95% CI: 1.1-2.0). In contrast, completion of 3-4 doses of PCV13 were associated with a lower carriage rate (aOR = 0.6, 95% CI: 0.4-0.9). CONCLUSIONS: We established the baseline of pneumococcal carriage, serotype distribution and PCV13 immunization rates among healthy children under 5 years of age in Hainan Province, prior to the introduction of PCV13 into the national immunization program. The high proportion of PCV13 serotypes suggests that PCV13 introduction will likely have a substantial impact on pneumococcal carriage in Hainan Province.

Cannabidiol Exerts Sedative and Hypnotic Effects in Normal and Insomnia Model Mice Through Activation of 5-HT1A Receptor.

Cannabis sativa has been used for improving sleep for long history. Cannabidiol (CBD) has drown much attention as a non-addictive psychoactive component in Cannabis sativa extract. However, the effects of CBD on sleep architecture and it's acting mechanism remains unclear. In the present study, we evaluated the sedative-hypnotic effect of cannabidiol (CBD), assessed the effects of CBD on sleep using a wireless physiological telemetry system. We further explored the therapeutic effects of CBD using 4-chloro-dl-phenylalanine (PCPA) induced insomnia model and changes in sleep latency, sleep duration and intestinal flora were evaluated. CBD shortened sleep latency and increases sleep duration in both normal and insomnia mice, and those effects were blocked by 5-HT1A receptor antagonist WAY100635. We determined that CBD increases 5-HT1A receptors expression and 5-HT content in the hypothalamus of PCPA-pretreated mice and affects tryptophan metabolism in the intestinal flora. These results showed that activation of 5-HT1A receptors is one of the potential mechanisms underlying the sedative-hypnotic effect of CBD. This study validated the effects of CBD on sleep and evaluated its potential therapeutic effects on insomnia.

Refinement of sensitive azides via in situ generated azole-based metal-organic frameworks towards stable energetic materials.

Energetic materials (EMs) have been widely employed in both military and civilian areas for nearly two centuries. The introduction of high-energy azide anions to assemble energetic metal-organic frameworks (EMOFs) is an efficient strategy to enhance energetic properties. However, azido-based EMOFs always suffer low stabilities to external mechanical stimulation. Herein, we employed an in situ hydrothermal reaction as a technique to refine azide anions with a neutral triazole-cyano-based ligand TrzAt (TrzAt = 2-(1H-1,2,4-triazol-1-yl)acetonitrile) to yield two tetrazole-based EMOFs, namely, [ZnBr(trmetz)]n1 and [Cd(trmetz)2]n2 (Htrmetz = 5-(1,2,4-triazol-1-ylmethyl)-1H-tetrazole). Compound 1 features a closely packed 2D layered network, while compound 2 exhibits a 3D architecture. With azide anions inlaid into a nitrogen-rich and chelating ligand in the EMOFs, compounds 1 and 2 present remarkable decomposition temperatures (Tdec ≥ 300 °C), low impact sensitivities (IS ≥ 32 J) and low friction sensitivities (FS ≥ 324 N). The calculated heat of detonation (ΔHdet) values of 1 and 2 are 3.496 and 4.112 kJ g-1, respectively. In particular, the ΔHdet value of 2 is higher than that of traditional secondary explosives such as 2,4,6-trinitrotoluene (TNT, ΔHdet = 3.720 kJ g-1). These results indicate that EMOFs 1 and 2 may serve as potential replacements for traditional secondary explosives. This work provides a simple and effective strategy to obtain two EMOFs with satisfactory energy densities and reliable stabilities through an in situ hydrothermal technique for desensitization of azide anions.

Coordination polymerization of nitrogen-rich linkers and dicyanamide anions toward energetic coordination polymers with low sensitivities.

The design and synthesis of energetic materials (EMs) with high energy and reliable stabilities has attracted much attention in the field of EMs. In this work, we employed a strategy of the coordination polymerization of mild dicyanamide ions (DCA-), two isomeric ligands 1-methyl-5-aminotetrazole (1-MAT) and 2-methyl-5-aminotetrazole (2-MAT) to construct energetic coordination polymers (ECPs). Four new ECPs {[Co(DCA)2(1-MAT)2]·H2O}n1, [Cu(DCA)2(1-MAT)]n2, [Cd(DCA)2(1-MAT)2]n3 and [Cd(DCA)2(2-MAT)2]n4 were successfully synthesized through solvent evaporation routes. Compounds 1 and 4 display 1D chains, while 2 and 3 exhibit 2D-layered structures. Compounds 1-3 with the 1-MAT ligand all exhibit reliable thermal stabilities (> 200 °C). The calculated heats of detonation (ΔHdet) of 1-3 are all higher than 1.4 kJ g-1, which are higher than traditional explosive TNT (1.22 kJ g-1) and the reported ECP AgMtta (HMtta = 5-methyl-1H-tetrazole, ΔHdet = 1.32 kJ g-1). Furthermore, sensitivity testing demonstrates that 1-4 features low mechanical sensitivity to external mechanical action in contrast with the extremely sensitive azide-based ECPs [Cu3(2-MAT)2(N3)6]n. In addition, compound 2 shows hypergolic properties via an 'oxidizer-fuel' drop experiment, demonstrating its application prospects in the field of propellants. This work details an approach of synthesizing multipurpose ECPs with reliable stabilities by introducing mild dicyanamide anions into nitrogen-rich skeletons.

Regulating the Electronic Structure of Cu-Nx Active Sites for Efficient and Durable Oxygen Reduction Catalysis to Improve Microbial Fuel Cell Performance.

The efficient and durable oxygen reduction reaction (ORR) catalyst is of great significance to boost power generation and pollutant degradation in microbial fuel cells (MFCs). Although transition metal-nitrogen-codoped carbon materials are an important class of ORR catalysts, copper-nitrogen-codoped carbon is not considered a suitable MFC cathode catalyst due to the insufficient performance and especially instability. Herein, we report a three-dimensional (3D) hierarchical porous copper, nitrogen, and boron codoped carbon (3DHP Cu-N/B-C) catalyst synthesized by the dual template method. The introduced B atom as an electron donor increases the electron density around the Cu-Nx active site, which significantly promotes the efficiency of the ORR process and stabilizes the active site by preventing demetallization. Thus, the 3DHP Cu-N/B-C catalyst exhibited excellent ORR performance with the half-wave potential of 0.83 V (vs reversible hydrogen electrode (RHE)) in a 0.1 M KOH electrolyte and 0.68 V (vs RHE) in a 50 mM PBS electrolyte. Meanwhile, 3DHP Cu-N/B-C had satisfactory stability with 94.16% current retention after 24 h of chronoamperometry test, which is better than that of 20% Pt/C. The MFCs using 3DHP Cu-N/B-C not only showed a maximum power density of up to 760.14 ± 19.03 mW m-2 but also operating durability of more than 50 days. Moreover, the 16S rDNA sequencing results presented that the 3DHP Cu-N/B-C catalyst had a positive effect on the microbial community of the MFC with more anaerobic electroactive bacteria in the anode biofilm and fewer aerobic bacteria in the cathode biofilm. This study provides a new approach for the development of Cu-based ORR electrocatalysts as well as guidance for the rational design of high-performance MFCs.

All-Electrochemical Nanofabrication of Stacked Ternary Metal Sulfide/Graphene Electrodes for High-Performance Alkaline Batteries.

Energy-storage materials can be assembled directly on the electrodes of a battery using electrochemical methods, this allowing sequential deposition, high structural control, and low cost. Here, a two-step approach combining electrophoretic deposition (EPD) and cathodic electrodeposition (CED) is demonstrated to fabricate multilayer hierarchical electrodes of reduced graphene oxide (rGO) and mixed transition metal sulfides (NiCoMnSx ). The process is performed directly on conductive electrodes applying a small electric bias to electro-deposit rGO and NiCoMnSx in alternated cycles, yielding an ideal porous network and a continuous path for transport of ions and electrons. A fully rechargeable alkaline battery (RAB) assembled with such electrodes gives maximum energy density of 97.2 Wh kg-1 and maximum power density of 3.1 kW kg-1 , calculated on the total mass of active materials, and outstanding cycling stability (retention 72% after 7000 charge/discharge cycles at 10 A g-1 ). When the total electrode mass of the cell is considered, the authors achieve an unprecedented gravimetric energy density of 68.5 Wh kg-1 , sevenfold higher than that of typical commercial supercapacitors, higher than that of Ni/Cd or lead-acid Batteries and similar to Ni-MH Batteries. The approach can be used to assemble multilayer composite structures on arbitrary electrode shapes.

Sandwich-type immunosensor based on COF-LZU1 as the substrate platform and graphene framework supported nanosilver as probe for CA125 detection.

CA125 is a tumor marker which mainly exists in ovarian, the detection for it with high sensitivity is conducive to improve the effectiveness of tumor prevention and control at early state. Multi-layer graphene oxide derivatives from graphene, and has poor conductivity and high stacked properties that limit its further application. Multi-layer reduced graphene oxide frame (MrGOF) was composed of single-layer graphene sheet and exhibited 3D structure with good dispersion, better conductivity and electrochemical properties after multi-layer graphene oxide underwent alkaline peeling and thermally reduction, the modified graphene are easy to load and combine functional groups and metal nanoparticles. Covalent organic frameworks (COFs) presents a stable frame and through covalent bond connection and has porous properties to adsorb biomolecules, which allows the immobilization of antibody molecules by the porosity and improve the sensitivity of the detection in sensing field. Through the adsorption of COFs for antibody and the probe labeled with functional graphene, we constructed a sandwich type immunosensor with the new material COF-LZU1 as the platform to anchor the CA125 first-antibody and MrGOF combined with amino group and loaded with silver nanoparticles (AgNPs) as the probe to detect tumor marker CA125. The linear range of detection was from 0.001 U/mL to 40 U/mL, with the detection limit was calculated to be 0.00023 U/mL (S/N =3). The prepared immunosensor showed a good application ability for real human serum, which can be attributed to the adsorption of COF-LZU1 for the CA125 first-antibody, and ability to deliver electrons and signal amplification of AgNPs anchored on the sheet structure of MrGOF.

A Novel Electrochemical Immunosensor Based on COF-LZU1 as Precursor to Form Heteroatom-Doped Carbon Nanosphere for CA19-9 Detection.

Porous carbon sphere materials have a large variety of applications in several fields due to the large surface area, adaptable porosity, and good conductivity they possess. Obtaining a steady carbon sphere using the green synthesis method remains a significant challenge. In this experiment, covalent organic frameworks (COFs) were used as a precursor and Fe3O4NPs were integrated into the precursor in order to synthesize a porous carbon sphere material using the one-step pyrolysis method. COFs have an ordered porous structure, perpetual porosity, large surface area, and low density and display good environmental tolerance. These properties make them an excellent precursor for synthesizing porous carbon sphere, which maintains good morphology at high temperatures, and it is not involved in the removal of dangerous reagent and small size restrictions during the synthesis process. In addition to the formation of a porous carbon sphere, transition metal carbon material that contains N element can be an active catalyst. The composites exhibit better activity when Fe is doped into carbon materials containing N element than that of other doped transition metals including Mn and Co. In this situation, the integration of Fe3O4NPs and N element in the COF precursor exposed the active sites of the composites and the two substances synergistically improved the electrocatalytic properties, and the composites were named Fe3O4@NPCS. The constructed Fe3O4@NPCS/GCE immunosensor was applied as a means of detecting CA19-9 antigen and presented a wide linear range from 0.00001 to 10 U/mL with a low detection limit of 2.429 µU/mL (S/N = 3). In addition, the prepared immunosensor was utilized for detecting CA19-9 antigen in the real human serum, and the recovery rates were in the range from 95.24% to 106.38%. Therefore, a porous carbon sphere prepared by COFs as a precursor can be applied for the detection of CA19-9 antigen in real samples, which could be an excellent strategy for CA19-9 antigen detection and could potentially promote the development of COF materials in various electrochemical fields.

Dual function metal-organic frameworks based ratiometric electrochemical sensor for detection of doxorubicin.

Cancer is one of the main diseases threatening human health in the world. Doxorubicin (DOX) is a common anti-cancer drug that can be used for chemotherapy to extend a cancer patient's life. It is our common wish that treatment process of cancer is efficient and secure. Therefore, it is of great significance to develop sensitive, rapid and accurate techniques for anti-cancer drug doxorubicin (DOX) detection. Herein, in our work, a ratiometric electrochemical sensor for DOX detection was designed, which based on MB@MWCNTs/UiO-66-NH2 composites. The porous materials UiO-66-NH2 magically shoulder double function in our ratiometric electrochemical strategy, which can reduce the interior error caused by the various complex materials. Specifically, on the one hand, it can be used to catalyze DOX, which can provide a great current signal to be detected, on the other hand, its special property of absorbing molecules was utilized to load materials as internal reference. Consequently, we chose methylene blue (MB) as the substance that can generate an internal reference signal, because it is a specific and stable electroactive substance. Then, we added MWCNTs as a part of the material modified on the ratiometric electrochemical platform to enhance the signal of the target due to its feature of good electrical conductivity. Under the optimized conditions, the ratiometric electrochemical sensor displayed a wide linear detection with the range from 0.1 µM to 75 µM and the limit of detection (LOD) of 0.051 µM. The applicability of this method in the analysis of actual human saliva samples has been confirmed by the results of selectivity, stability, and reproducibility tests, which was prospective in clinical application.

A label-free electrochemical immunosensor for CA125 detection based on CMK-3(Au/Fc@MgAl-LDH)n multilayer nanocomposites modification.

A label-free electrochemical immunosensor was constructed for cancer antigen 125 (CA125) detection based on multiple-enlargement means of layer-by-layer (LBL) assembly of ordered mesoporous carbon (CMK-3), gold nanoparticles (Au NPs) and MgAl layered double hydroxides containing ferrocenecarboxylic acid (Fc@MgAl-LDH). A CMK-3(Au/Fc@MgAl-LDH)n multilaminate nanocomposites was designed using technology of LBL self-assembly among negatively charged Au NPs, positively charged CMK-3 and Fc@MgAl-LDH nanosheets. The CMK-3(Au/Fc@MgAl-LDH)n multilaminate nanocomposites was used as carriers to increase the immobilization of antibody and the number of loading Fc, conductors to strengthen conductivity and enhancers to amplify signal of Fc step-by-step. Besides, this special and excellent way of LBL assembly can immensely amplify the signal of immunosensor and more immobilize the biomolecules, and label-free method is a more simple the measuring way and the procedure. The immunosensor displayed a wider linear range of 0.01 U ml-1-1000 U ml-1 and a lower detection limit of 0.004 U ml-1. Therefore, the sensor can stablely and accurately be applied for CA125 detection in clinical cancer diagnosis.

Electrochemical Detection of Nuciferine in the Lotus Leaf Based on Efficient Catalysis by Zirconium-MOFs.

BACKGROUND: Nuciferine is an amorphine alkaloid in lotus leaf that has anti-inflammatory, lipid-lowering and hypoglycemic effects, so the quantitation of detected nuciferine is important. OBJECTIVE: An electrochemical method was developed for nuciferine detection based on efficient catalysis by Zr-MOFs (Metal-organic frameworks). METHODS: In this work, the ratiometric electrochemical method was developed for nuciferine detection based on efficient catalysis by Zr-MOFs. UiO66 is a Zr-MOFs nanomaterial and can absorb methylene blue (MB) by electrostatic action to form UiO66-MB nanocomposite. The UiO66-MB nanocomposite can be used as an enhancer to catalyze nuciferine decomposition and a carrier to provide a two-dimensional environment for the reaction of nuciferine. Moreover, good catalytic properties of UiO66 were first time used for the detection of nuciferine. RESULTS: This method has a linear detection range from 0.1 to approximately 20 µg/mL, and a low detection limit of 0.03 µg/mL (S/N=3). The recovery was from 98.1 to 102% and the RSD was from 0.45 to 3.65%, indicating that the proposed method can be applied for the analysis of real samples. CONCLUSION: The proposed electrochemical method can be used to detect nuciferine in lotus leaves. HIGHLIGHTS: The ratiometric electrochemical method was used for the detection of nuciferine. The MB can be used as an internal standard for anti-interference. And, UiO66 is used to catalyze the decomposition of nuciferine. Great catalytic properties of UiO66 were first time used for the detection of nuciferine.

Biological functions of nuclear-localized insulin receptor (IR) on A549 lung cancer cells.

INTRODUCTION: Under normal physiological conditions, insulin exhibits a series of important biological functions and roles. Recent studies have shown that insulin is also closely related to the occurrence and development of lung cancer. However, until now, the cellular properties of insulin/insulin receptor (IR) on lung cancer have not been fully revealed. MATERIAL AND METHODS: Indirect immunofluorescence, western blot, and other techniques have been used to identify the biological activity of insulin on lung cancer cell lines. RESULTS: The biological activities of insulin are closely related to its cell behaviour. Therefore, we used lung cancer cell lines as a model to explore the cellular behaviour and properties of insulin/IR in the current study, and the results showed that the IR could internalize into lung cancer cells, and it can also transport into the cell nuclei under insulin treatment. Further study showed that nuclear-localized IR could promote the proliferation of lung cancer cells. CONCLUSION: Taken together, this study shows that IR's nuclear localization is closely related to cell proliferation. This work lays the foundation for further research on the relationship between insulin and the occurrence and development of lung cancer.

Co, N co-doped hierarchical porous carbon as efficient cathode electrocatalyst and its impact on microbial community of anode biofilm in microbial fuel cell.

The exploration of low-cost, long-term stable, and highly electrochemically active cathode catalysts is important for the practical application of microbial fuel cell (MFC). In this work, a series of the 3D hierarchical porous Co-N-C (3DHP Co-N-C) materials are designed and synthesized by a metal-organic framework ZIF-67 as a precursor and SiO2 sphere of different sizes as the hard template. The 3DHP Co-N-C-2 with 129 nm macropore exhibits excellent ORR performance in 0.1 M KOH solution with a half-wave potential of 0.80 V vs. RHE and superior durability than Pt/C (20%) due to the specific macropore-mesopore-micropore structure that exposes a large number of active sites and accelerates the electrolyte transport and oxygen diffusion. The MFC with 3DHP Co-N-C-2 as the cathode catalysts shows excellent performance with a maximum power density of 426.9±7.87 mW m-2 and favorable durability after 50 d of operation. In addition, 16s rDNA results reveal the presence of different dominant electrogenic bacteria and different abundance of important non-electrogenic bacteria in the anode biofilm in MFCs using cathode catalysts with different ORR activity. And 3DHP Co-N-C-2 was found to be beneficial to the synergistic effect of electrogenic and non-electrogenic bacteria. This study explores electrocatalysts in terms of both electrocatalytic activity and anode microorganisms, providing new and comprehensive insights into the power generation of MFC.

Real-time imaging of Na+ reversible intercalation in "Janus" graphene stacks for battery applications.

Sodium, in contrast to other metals, cannot intercalate in graphite, hindering the use of this cheap, abundant element in rechargeable batteries. Here, we report a nanometric graphite-like anode for Na+ storage, formed by stacked graphene sheets functionalized only on one side, termed Janus graphene. The asymmetric functionalization allows reversible intercalation of Na+, as monitored by operando Raman spectroelectrochemistry and visualized by imaging ellipsometry. Our Janus graphene has uniform pore size, controllable functionalization density, and few edges; it can store Na+ differently from graphite and stacked graphene. Density functional theory calculations demonstrate that Na+ preferably rests close to -NH2 group forming synergic ionic bonds to graphene, making the interaction process energetically favorable. The estimated sodium storage up to C6.9Na is comparable to graphite for standard lithium ion batteries. Given such encouraging Na+ reversible intercalation behavior, our approach provides a way to design carbon-based materials for sodium ion batteries.

A simple method for the preparation of a nickel selenide and cobalt selenide mixed catalyst to enhance bifunctional oxygen activity for Zn-air batteries.

Developing a low-cost, simple, and efficient method to prepare excellent bifunctional electrocatalysts toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical in rechargeable zinc-air batteries. Non-stoichiometric M0.85Se (M = Ni or Co) nanoparticles are synthesized and modified on nitrogen-doped hollow carbon sphere (NHCS). The NHCS loaded Ni0.85Se (Ni0.85Se-NHCS) with rich Ni3+ presents higher OER activity, whereas the NHCS-loaded Co0.85Se (Co0.85Se-NHCS) with abundant Co2+ displays better ORR activity, respectively. When Co0.85Se-NHCS is mixed with Ni0.85Se-NHCS in a mass ratio of 1 : 1, the resulting mixture (Ni0.85Se/Co0.85Se-NHCS-2) shows better ORR and OER dual catalytic functions than a single selenide. Moreover, zinc-air batteries equipped with Ni0.85Se/Co0.85Se-NHCS-2 as the oxygen electrode catalyst exhibit excellent charge and discharge performance as well as improved stability over precious metals. This work has developed a simple and effective method to prepare excellent bifunctional electrocatalysts for ORR and OER, which is beneficial for the practical large-scale application of zinc-air batteries.

Fatigue crack growth characteristics of Fe and Ni under cyclic loading using a quasi-continuum method.

A quasi-continuum (QC) method based on the embedded atom method (EAM) potential was employed to investigate the fatigue crack growth and expansion characteristics of single-crystal Fe and Ni under cyclic loading modes I and II. In particular, the crack growth and expansion characteristics of Fe and Ni under cyclic loading were evaluated in terms of atomic stress fields and force-distance curves. The simulation results indicated that under cyclic loading, the initially damaged area of the crack will coalesce again after compression or shear to the initial geometry leading to a strengthening of the material. If no coalescence appears, the crack spreads rapidly and the material breaks. Moreover, under the cyclic loading of shear at any orientation, the slip dislocation observed in the materials considerably affects the release of stress.

Gallic acid-assisted synthesis of Pd uniformly anchored on porous N-rGO as efficient electrocatalyst for microbial fuel cells.

The sluggish kinetic rate-limiting oxygen reduction reaction (ORR) at the cathode remains the foremost issue hindering the commercialization of microbial fuel cells (MFCs). Utilization of the effect of micromolecule conjugation and the synergistic effect between Pd nanoparticles and N-rGO (nitrogen-doped reduced graphene oxide) to stabilize a precious metal onto carbon materials is a promising strategy to design and synthesize highly efficient cathode catalysts. In this study, gallic acid is used to facilitate the coupling of palladium (Pd) with N-rGO to form GN@Pd-GA via a simple hydrothermal process. Notably, the as-synthesized GN@Pd-GA as a cathode catalyst shows an approximately direct four-electron feature and demonstrates a high ORR performance in 0.1 M KOH. Furthermore, the stability and methanol tolerance of GN@Pd-GA are superior to those of the commercial Pt/C catalysts. In addition, a maximum power density of 391.06 ± 0.2 mW m-2 of MFCs equipped with GN@Pd-GA was obtained, which was 96.2% of the power density of MFCs equipped with a commercial Pt/C catalyst.

Mechanism and effect of γ-butyrolactone solvent vapor post-annealing on the performance of a mesoporous perovskite solar cell.

In this paper, γ-butyrolactone (GBL) solvent vapor post-annealing (SVPA) on CH3NH3PbI3 thin films is reported, aiming to improve the complete transformation of PbI2 and increase the grain size of the CH3NH3PbI3 crystal, thus boosting the performance of mesoporous CH3NH3PbI3 perovskite solar cells (PSCs). The influence of GBL SVPA on the microstructure of perovskite layers and performance of PSCs was studied. The short circuit current density (J sc) of the devices significantly increased, yielding a high efficiency of 16.58%, which was 27.05% higher than that of thermally annealed films. A model was derived to explain the effect of GBL SVPA on PSCs. The perovskite films prepared by this method present several advantages such as complete transformation of PbI2 to CH3NH3PbI3, high crystallinity, large grain size, and fewer grain boundaries than those prepared without GBL SVPA. This improvement is beneficial for charge dissociation and transport in hybrid photovoltaic devices.

Molecular dynamics simulations of nanoindentation and scratch in Cu grain boundaries.

The dynamic nanomechanical characteristics of Cu films with different grain boundaries under nanoindentation and scratch conditions were studied by molecular dynamics (MD) simulations. The type of grain boundary is the main factor in the control of the substrate atoms with respect to the size of dislocations since the existence of the grain boundary itself restricts the movement associated with dislocations. In this work, we analyzed the transverse and vertical grain boundaries for different angles. From the simulation results, it was found that the sample with a transverse grain boundary angle of 20° had a higher barrier effect on the slip band as compared to samples with other angles. Moreover, the nanoindentation results (i.e., indentation on the upper area) of the vertical grain boundary showed that the force was translated along the grain boundary, thereby producing intergranular fractures.