•Chlorosulfonic acid modified zirconia was applied in biodiesel production.•FAME yield reached 100% consecutively for 5 cycles even under mild conditions.•Catalyst synthesis condition-activities ...relations were studied.
Biodiesel is a promising renewable alternative to fossil energy. Biodiesel production from low-cost feedstock involves an essential pretreatment step – esterification of free fatty acids (e.g. oleic acid), for avoiding soap formation and catalyst deactivation. Sulfuric acid modified zirconia (H2SO4–ZrO2) is known to be an effective heterogeneous catalyst for this reaction. However, due to rapid SO42- leaching, its reusability is low and its practical use is thus largely hindered. Herein, we report a more stable solid acid analogue for the reaction, chlorosulfonic acid modified zirconia (HClSO3–ZrO2). It was characterized by XRD, SEM, BET, EDX, IR, TGA, and NH3-TPD. Compared with H2SO4–ZrO2, there is over 3 times more sulfur content and nearly 4 times more acid sites amount for HClSO3–ZrO2. More importantly, HClSO3–ZrO2 demonstrates high catalytic activity and long durability in esterification of oleic acid, in which the fatty acid methyl ester yield reaches 100% consecutively for at least 5 cycles under mild conditions.
A series of luminescent cyclometalated N^C^N N^C^N = 1,3-bis(N-alkylbenzimidazol-2′-yl)benzeneplatinum(II) alkynyl and carbazolyl complexes has been prepared. The structure of one ...platinum(II) carbazolyl complex has been characterized by X-ray crystallography. The corresponding electrochemical and photophysical properties have been explored and analyzed. The N^C^N platinum(II) complexes displayed rich luminescence in degassed dichloromethane solution, with their emission profiles dependent on the coordinated alkynyl and carbazolyl ligands. Their emission energies are correlated to the electronic properties of the alkynyl and carbazolyl ligands. By varying the electronic properties of the alkynyl and carbazolyl ligands, emission energies could be fine-tuned to cover a wide range of the visible spectrum, as supported by computational studies. A donor–acceptor platinum(II) complex has been utilized to fabricate memory devices that exhibit binary memory performances with low operating voltages, high ON/OFF ratios, and long retention times. Solution-processable OLEDs have been fabricated based on another platinum(II) carbazolyl complex, resulting in a maximum external quantum efficiency of up to 7.2%, which is comparable to that of the vacuum-deposited devices based on the small-molecule counterpart, illustrating the multifunctional nature of the platinum(II)-containing materials.
Liposomes are small spherical vesicles composed mainly of phospholipids and cholesterol. Over the years, a number of liposomal formulations have shown clinical promise, but the use of liposomes in ...oral drug delivery is limited. This is partly due to the vulnerability of conventional liposomes to the detrimental effect of gastrointestinal destabilizing factors and also to the poor efficiency in intestinal absorption of liposomes. Some of these issues can be ameliorated using the layer-by-layer (LbL) assembly technology, which has been widely applied to modify the surface of various nanoparticulate systems. Discussions about LbL functionalization of liposomes as oral drug carriers, however, are scant in the literature. To fill this gap, this review presents an overview of the roles of LbL functionalization in the development of liposomes, followed by a discussion about major principles of molecular design and engineering of LbL-functionalized liposomes for oral drug delivery. Regarding the versatility offered by LbL assembly, it is anticipated that LbL-functionalized liposomes may emerge as one of the important carriers for oral drug administration in the future.
Polymeric films for active food packaging have been playing an important role in food preservation due to favorable properties including high structural flexibility and high property tunability. Over ...the years, different polymeric active packaging films have been developed. Many of them have found real applications in food production. This article reviews, using a practical perspective, the principles of designing polymeric active packaging films. Different factors to be considered during materials selection and film generation are delineated. Practical considerations for the use of the generated polymeric films in active food packaging are also discussed. It is hoped that this article cannot only present a snapshot of latest advances in the design and optimization of polymeric active food packaging films, but insights into film development to achieve more effective active food packaging can be attained for future research.
An efficient selenium‐catalyzed direct oxidation of benzylpyridines in aqueous DMSO has been successfully developed by using molecular oxygen as the oxidant. A variety of benzoylpyridines with broad ...functional group tolerance were obtained in modest to excellent yields and with exclusive chemoselectivity.
The synthesis, characterization, electrochemistry, photophysics and photochromic behavior of a new class of cyclometalated platinum(II) complexes Pt(C∧N)(O∧O) (1a–5a and 1b–5b), where C∧N is a ...cyclometalating 2-(2′-thienyl)pyridyl (thpy) or 2-(2′-thienothienyl)pyridyl (tthpy) ligand containing the photochromic dithienylethene (DTE) unit and O∧O is a β-diketonato ligand of acetylacetonato (acac) or hexafluoroacetylacetonato (hfac), have been reported. The X-ray crystal structures of five of the complexes have also been determined. The electrochemical studies reveal that the first quasi-reversible reduction couple, and hence the nature of lowest unoccupied molecular orbital (LUMO) of the complexes, is sensitive to the nature of the ancillary O∧O ligands. Upon photoexcitation, complexes 1a–3a and 1b–3b exhibit drastic color changes, ascribed to the reversible photochromic behavior, which is found to be sensitive to the substituents on the pyridyl ring and the extent of π-conjugation of the C∧N ligand as well as the nature of the ancillary ligand. The thermal bleaching kinetics of complex 1a has been studied in toluene at various temperatures, and the activation barrier for the thermal cycloreversion of the complex has been determined. Density functional theory (DFT) calculations have been performed to provide an insight into the electrochemical, photophysical and photochromic properties.
miRNA is a class of short noncoding RNA that regulates gene expression at the post-transcriptional level. Evidence of age-associated changes in miRNA expression has been collected in models ranging ...from nematodes to humans; however, there has been little discussion of how to turn our knowledge of miRNA biology into antiaging therapy. This opinion article provides a snapshot of our current understanding of the roles of miRNA in modulating the aging process. We discuss major chemical techniques for modifying the miRNA structure as well as developing delivery systems for intervention. Finally, technical needs to be met for bench-to-clinic translation of miRNA-based interventions are highlighted for future research.
The accumulated knowledge of miRNA biology has established a foundation for using miRNA as a target and a tool for the development of antiaging interventions.The identification of miRNA for antiaging interventions has been facilitated by the use of in silico methods to identify hairpin structures in noncoding and nonrepetitive regions in genome sequences.Diverse miRNA analogs including phosphorothioate oligodeoxynucleotides (ODNs), locked nucleic acid (LNA) oligonucleotides, and peptide nucleic acids (PNAs) have been generated to enhance the gene-silencing efficiency of miRNA therapeutics.Both viral and nonviral systems have been developed to deliver miRNA therapeutics, and some allow real-time tracking of the delivery process and codelivery of multiple agents.
Due to their large anti-Stokes shifts, sharp emission spectra and long excited-state lifetimes, upconversion nanoparticles (UCNPs) have attracted an increasing amount of research interests, and have ...shown great potential for enhancing the practical utility of gene therapy, whose versatility has been limited by existing gene delivery technologies that are basically mono-functional in nature. Despite this, up to now in-depth analysis of the development of UCNPs for gene delivery has been scant in the literature, even though there has been an upsurge of reviews on the chemistry of UCNPs and their applications in bioimaging and drug delivery. To fill this gap, this review aims to present the latest advances in the development and applications of UCNPs as gene carriers. Prior to describing the prominent works published in the field, a critical view on the properties, chemistry and molecular design of UCNPs for gene delivery is provided. With a synopsis of the recent advances in UCNP-mediated gene delivery, challenges and opportunities could be illuminated for clinical translation of works in this nascent field of research.
Upconversion nanoparticles (UCNPs) represent an important topic in nanotechnology, and have extended possibilities in gene delivery beyond the reach of many existing technologies.
Turmeric (Curcuma longa L.), a spice and food coloring agent in food preparation, contains a carotenoid pigment called curcumin. Curcumin has attracted extensive research interest owing to its health ...benefits, ranging from neuroprotection to chemoprevention and antioxidation. It also exhibits anti-cancer effects due to its capacity to inhibit cancer cell proliferation and stimulate apoptosis. However, the health-promoting effects of curcumin are limited by its poor aqueous solubility and low oral bioavailability. This article presents an overview of the latest understanding of the biological effects of curcumin and its use as a food additive in the development of functional food products.
Bispecific antibodies are artificial molecules that fuse two different antigen-binding sites of monoclonal antibodies into one single entity. They have emerged as a promising next-generation ...anticancer treatment. Despite the fascinating applications of bispecific antibodies, the design and production of bispecific antibodies remain tedious and challenging, leading to a long R&D process and high production costs. We herein report an unprecedented strategy to cyclise and conjugate tumour-targeting peptides on the surface of a monoclonal antibody to form a novel type of bispecific antibody, namely the peptidic bispecific antibody (pBsAb). Such design combines the merits of highly specific monoclonal antibodies and serum-stable cyclic peptides that endows an additional tumour-targeting ability to the monoclonal antibody for binding with two different antigens. Our results show that the novel pBsAb, which comprises EGFR-binding cyclic peptides and an anti-SIRP-α monoclonal antibody, could serve as a macrophage-engaging bispecific antibody to initiate enhanced macrophage–cancer cell interaction and block the “don't eat me” signal between CD47-SIRP-α, as well as promoting antibody-dependent cellular phagocytosis and 3D cell spheroid infiltration. These findings give rise to a new type of bispecific antibody and a new platform for the rapid generation of new bispecific antibodies for research and potential therapeutic uses.
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