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2296-2646
Updated Sunday, 17 October 2021

2021 ◽  
Vol 9 ◽  
Author(s):  
Dandan Hong ◽  
Jingjing Wu ◽  
Xuemin Xiao ◽  
Xueyang Li ◽  
Dong Xu ◽  
...  

Antimicrobial peptides (AMPs) have great potential for clinical treatment of bacterial infection due to the broad-spectrum and highly effective antibacterial activity. However, the easy degradation and inactivation in vivo has been a major obstacle for their application and an effective delivery system is demanding. The surface physicochemical properties of the carrier, including surface potential, surface polarity, pore structure and morphology, have exerted great effects on the adsorption and release behavior of AMPs. This study investigated the influence of micro/nano carriers with different hierarchical structures on the loading, release and biological behavior of AMPs. Three types of AMPs-loaded hydroxyapatite microspheres (HA/AMPs MSs) with different hierarchical structures (needle-like, rod-like, and flake-like) were developed, which was investigated by the surface morphology, chemical composition and surface potential in detail. The different hierarchical structures of hydroxyapatite microspheres (HA MSs) had noticeable impact on the loading and release behavior of AMPs, and the flake-like HA MSs with hierarchical structure showed the highest loading efficiency and long-lasting release over 9 days. Meanwhile, the stability of AMPs released from HA MSs was effectively maintained. Moreover, the antibacterial test indicated that the flake-like HA/AMPs MSs showed more sustained antibacterial properties among three composites. In view of the excellent biocompatibility and osteogenic property, high loading efficiency and the long-term release properties of HA MSs with hierarchical structure, the HA/AMPs MSs have a great potential in bone tissue engineering.


2021 ◽  
Vol 9 ◽  
Author(s):  
Minggui Wang ◽  
Min Wang ◽  
Fang Peng ◽  
Xiaohuan Sun ◽  
Jie Han

Herein, g-C3N4/CdS hybrids with controllable CdS nanoparticles anchoring on g-C3N4 nanosheets were constructed. The effects of CdS nanoparticles on photocatalytic H2 production and organic molecule degradation for g-C3N4/CdS hybrids were investigated. The maximum rate of H2 production for g-C3N4/CdS sample was 1,070.9 μmol g−1 h−1, which was about four times higher than that of the individual g-C3N4 nanosheet sample. The enhanced photocatalytic performance for prepared hybrids could be mainly attributed to the following causes: the formed heterojunctions can contribute to the light absorption and separation of photogenerated electrons and holes, the two-dimensional layered structure facilitates the transmission and transfer of electrons, and high specific surface area could provide more exposed active sites.


2021 ◽  
Vol 9 ◽  
Author(s):  
Ivana Kosarac ◽  
Cariton Kubwabo ◽  
Xinghua Fan ◽  
Shabana Siddique ◽  
Dora Petraccone ◽  
...  

Currently, there is a lack of comprehensive data on the diversity of chemicals present in vaping liquids. To address this gap, a non-targeted analysis of 825 vaping liquids collected between 2017 and 2019 from Canadian retailers was conducted. Prior to mass spectrometry analysis, samples were diluted 1:500 v/v with methanol or acetonitrile. Chemical compound separation and analysis was carried out using gas chromatography and triple quadrupole mass spectrometry (GC-MS/MS) systems operated in the full scan mode and mass range of 35–450 m/z. Mass spectrum for each sample was obtained in electron ionization at 70 eV and processed. Non-targeted identification workflow included use of automated mass spectral deconvolution and identification system (AMDIS), where required, as well as a number of commercially available spectral libraries. In order to validate identities, an in-house database of expected compounds previously detected in vaping liquids was used along with genuine analytical standards for compounds of interest. This resulted in a dataset of over 1,500 unique detected chemicals. Approximately half of these chemical compounds were detected only once in a single product and not in multiple products analyzed. For any sample analyzed, on average, 40% of the chemical constituents appeared to have flavouring properties. The remainder were nicotine and related alkaloids, processing, degradation or indirect additives, natural extractives and compounds with unknown roles. Data published here from the project on the Open Characterization of vaping liquids is unique as it offers a detailed understanding of products’ flavour chemical profiles, the presence and frequency of chemicals of potential health concern, as well as trends and changes in products’ chemical complexity over a three-year period. Non-targeted chemical surveillance such as this present valuable tools to public health officials and researchers in responding to emergent issues such as vaping associated lung injury or informing chemical based strategies which may be aimed at addressing product safety or appeal.


2021 ◽  
Vol 9 ◽  
Author(s):  
Paweł Mateusz Nowak ◽  
Renata Wietecha-Posłuszny ◽  
Michał Woźniakiewicz ◽  
Aneta Woźniakiewicz ◽  
Małgorzata Król ◽  
...  

The recently proposed concept of White Analytical Chemistry (WAC), referring to the Red-Green-Blue color model, combines ecological aspects (green) with functionality (red and blue criteria), presenting the complete method as “white”. However, it is not easy to carry out an overall quantitative evaluation of the analytical method in line with the WAC idea in an objective manner. This paper outlines the perspective of the future development of such a possibility by attempting to answer selected questions about the evaluation process. Based on the study consisting in the evaluation of selected model methods by a group of 12 independent analysts, it was shown how well individual criteria are assessed, whether the variability of assessments by different people is comparable for each criterion, how large it is, and whether averaging the scores from different researchers can help to choose the best method more objectively.


2021 ◽  
Vol 9 ◽  
Author(s):  
Dong Xiang ◽  
Biao Zhang ◽  
Hongsheng Zhang ◽  
Liangping Shen

The Ni2P nanowires were simply synthesized via a rapid one-step hydrothermal approach, in which deionized water, red phosphorus, nickel acetate, and hexadecyl trimethyl ammonium bromide were used as the solvent, phosphor and nickel sources, and active agent, respectively. The as-synthesized Ni2P nanowire clusters were composed of uniform nanowires with length of about 10 μm and diameter of about 40 nm. The Ni2P nanowires exhibited enhanced electrocatalytic activity for both hydrogen evolution reaction and oxygen evolution reaction This work provides good guidance for the rational design of nickel phosphides with unique nanostructures for highly efficient overall water splitting.


2021 ◽  
Vol 9 ◽  
Author(s):  
Xiantun Huang ◽  
Haizhen Liu ◽  
Xingqing Duan ◽  
Zhiqiang Lan ◽  
Jin Guo

Mg−Li alloy possesses a high hydrogen capacity. However, the hydrogenation and dehydrogenation performances are still far from practical application. In this work, Mg2Si (MS) and graphene (G) were employed together to synergistically improve the hydrogen storage properties of Mg−Li alloy. The structures of the samples were studied by XRD and SEM methods. The hydrogen storage performances of the samples were studied by nonisothermal and isothermal hydrogenation and dehydrogenation, thermal analysis, respectively. It is shown that the onset dehydrogenation temperature of Mg−Li alloy was synergistically reduced from 360°C to 310°C after co-addition of Mg2Si and graphene. At a constant temperature of 325°C, the Mg−Li−MS−G composite can release 2.7 wt.% of hydrogen within 2 h, while only 0.2 wt.% of hydrogen is released for the undoped Mg−Li alloy. The hydrogenation activation energy of the Mg−Li−MS−G composite was calculated to be 86.5 kJ mol−1. Microstructure and hydrogen storage properties studies show that graphene can act as a grinding aid during the ball milling process, which leads to a smaller particle size for the composites. This work demonstrates that coaddition of Mg2Si and graphene can synergistically improve the hydrogen storage properties of Mg−Si alloy and offers an insight into the role of graphene in the Mg−Li−MS−G composite.


2021 ◽  
Vol 9 ◽  
Author(s):  
Heba E. Elsayed ◽  
Reem A. Kamel ◽  
Reham R. Ibrahim ◽  
Ahmed S. Abdel-Razek ◽  
Mohamed A. Shaaban ◽  
...  

Endophytes are prolific producers of privileged secondary metabolites with diverse therapeutic potential, although their anticancer and antimicrobial potential still have a room for further investigation. Herein, seven known secondary metabolites namely, arugosin C (1), ergosterol (2), iso-emericellin (3), sterigmatocystin (4), dihydrosterigmatocystin (5), versicolorin B (6), and diorcinol (7) were isolated from the rice culture of Aspergillus sp. retrieved from Tecoma stans (L.) Juss. ex Kunth leaves. Their anticancer and antimicrobial activities were evaluated in MTT and agar well diffusion assays, respectively. The cytotoxicity results showed that metabolite 3 displayed the best viability inhibition on the MCF-7 breast cancer cells with IC50 = 225.21 µM, while 5 on the HepG2 hepatocellular carcinoma cells with IC50 = 161.81 µM. 5 demonstrated a 60% apoptotic mode of cell death which is virtually correlated to its high docking affinity to Hsp90 ATP binding cleft (binding score −8.4 Kcal/mol). On the other side, metabolites 4 and 5 displayed promising antimicrobial activity especially on Pseudomonas aeruginosa with MIC = 125 μg/ml. The observed effect may be likely related to their excellent in silico inhibition of the bacterial DNA-gyrase kinase domain (binding score −10.28 Kcal/mol). To the best of our knowledge, this study is the first to report the promising cytotoxic and antibacterial activities of metabolites 3, 4, and 5 which needs further investigation and renovation to therapeutic leads.


2021 ◽  
Vol 9 ◽  
Author(s):  
Lin Guo ◽  
Qiaoli Yang ◽  
Guangfei Wang ◽  
Shumin Zhang ◽  
Ming Liu ◽  
...  

Angucyclines and angucyclinones represent the largest family of type II PKS-engineered natural products. Chemical analysis of a marine Streptomyces sp. KCB-132 yielded three new members, actetrophenone A (1) and actetrophenols A–B (2–3). Their structures were elucidated by NMR spectroscopy, X-ray crystallography and CD calculations. Actetrophenone A (1) is the first representative of a novel-type angucyclinone bearing a nonaromatic D-ring. Actetrophenol A (2) features a highly reduced and aromatized four-ring system, which is unprecedented for natural products. While (Ra)- and (Sa)-actetrophenol B (3) bear an unprecedented N-acetyltryptamine-substituted tetraphene core skeleton, this is the first report of a pair of atropisomeric isomers in the angucyclinone family. Actetrophenol A (2) exhibits remarkable antibiotic activity, notably including potent activity to multiple resistant Staphylococcus aureus and Enterococcus faecium with MIC values of 4 μg/ml, in contrast, the positive control antimicrobial agent penicillin was inactive up to 32 μg/ml.


2021 ◽  
Vol 9 ◽  
Author(s):  
Wenqiang Zhu ◽  
Junjian Zhou ◽  
Shuang Xiang ◽  
Xueting Bian ◽  
Jiang Yin ◽  
...  

Silicon (Si) has been counted as the most promising anode material for next-generation lithium-ion batteries, owing to its high theoretical specific capacity, safety, and high natural abundance. However, the commercial application of silicon anodes is hindered by its huge volume expansions, poor conductivity, and low coulombic efficiency. For the anode manufacture, binders play an important role of binding silicon materials, current collectors, and conductive agents, and the binder structure can significantly affect the mechanical durability, adhesion, ionic/electronic conductivities, and solid electrolyte interface (SEI) stability of the silicon anodes. Moreover, many cross-linked binders are effective in alleviating the volume expansions of silicon nanosized even microsized anodic materials along with maintaining the anode integrity and stable electrochemical performances. This mini review comprehensively summarizes various binders based on their structures, including the linear, branched, three-dimensional (3D) cross-linked, conductive polymer, and other hybrid binders. The mechanisms how various binder structures influence the performances of the silicon anodes, the limitations, and prospects of different hybrid binders are also discussed. This mini review can help in designing hybrid polymer binders and facilitating the practical application of silicon-based anodes with high electrochemical activity and long-term stability.


2021 ◽  
Vol 9 ◽  
Author(s):  
Di Hu ◽  
Hong Xu ◽  
Zuotong Wu ◽  
Man Zhang ◽  
Zhiyue Zhao ◽  
...  

Developing a low-cost and robust catalyst for efficient transformation of biomass-derived platform chemicals plays a crucial role in the synthesis of future transportation fuels. Herein, a post-synthetic strategy was employed to develop a noble metal-free and robust ZrY zeolite catalyst, which is efficient for the hydrogenation of biomass-derived levulinic acid (LA) into biofuel γ-valerolactone (GVL), whereas over 95% yield of GVL was achieved in 10 h at 220°C. The effects of acidic properties from ZrY catalysts and various reaction parameters on the catalytic performance were then discussed in detail. Subsequently, different characterization tools were used to compare the difference and relationship of structure activity between the fresh and spent ZrY catalysts. It was found that acidity and the metal–support interaction were important for the direct synthesis of GVL. This work provides a guideline to design a noble metal-free catalyst for high-value utilization of biomass-derived sources.


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