Exploring the evolving roles and clinical significance of circRNAs in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) represents the predominant malignancies in the head and neck region, and has limited therapeutic alternatives. Circular RNAs (circRNAs), a substantial category of non-coding RNA molecules, exert influential roles in human disease development and progression, employing various mechanisms such as microRNA sponging, interaction with RNA-binding proteins, and translational capabilities. Accumulating evidence highlights the differential expression of numerous circRNAs in HNSCC, and numerous dysregulated circRNAs underscore their crucial involvement in malignant advancement and resistance to treatment. This review aims to comprehensively outline the characteristics, biogenesis, and mechanisms of circRNAs, elucidating their functional significance in HNSCC. In addition, we delve into the clinical implications of circRNAs, considering their potential as biomarkers or targets for diagnosis, prognosis, and therapeutic applications in HNSCC. The discussion extends to exploring future challenges in the clinical translation of circRNAs, emphasizing the need for further research.

Perceived Threat of Alzheimer's Disease and Related Dementias Among Chinese Family Caregivers of Older Adults with Cognitive Impairment.

Perceived threat of Alzheimer's disease and related dementias (ADRD) has been found a widespread phenomenon in developed countries, but has not yet been fully explored in developing countries. Analyzing data from 300 family caregivers of older adults with cognitive impairment in China, this study found caregiver burden was positively associated with the perceived threat of ADRD, and this association was buffered by higher family income and longer caregiving time. To alleviate undue ADRD concerns, it suggests expanding respite care and community elder care beds, and initiating education programs on reducing unnecessary worries about developing ADRD.

Rare-Earth Metal Phosphinidene Complexes: A Trip from Bridging One to Terminal One.

ConspectusAs phosphorus analogues of alkylidene (or carbene) and imido (or nitrene) complexes, phosphinidene complexes have received great attention not only for their fundamental scientific merits but also for their ability to build new phosphorus-containing molecules. A large number of phosphinidene complexes in bridging, mononuclear, or terminal coordination modes have been synthesized, and their reactivity has been extensively explored. However, the synthesis of rare-earth metal (scandium, yttrium, and lanthanide metal) phosphinidene complexes lagged behind the transition metal and actinide congeners for decades. Rare-earth metal ions are among the hardest Lewis acids, whereas phosphinidene ligands are soft Lewis bases; rare-earth metal-phosphinidene coordination is thus mismatched based on the Pearson's HSAB principle. The bridging rare-earth metal phosphinidene complexes were not reported until 2008, and the synthesis of the mononuclear and terminal species is even more challenging, which has only recently been achieved.Our group reported a bis(µ2-phosphinidene)dineodymium complex in 2008. In the following >10 years, we have been pursuing the terminal rare-earth metal phosphinidene complexes. Due to the high instability of rare-earth metal-phosphorus multiple bonds, the synthesis and stabilization of these complexes are extremely difficult. Finally, by using suitable phosphinidene ligands and supporting ligands, we obtained the first mononuclear rare-earth metal phosphinidene complex in 2018 and the first terminal rare-earth metal phosphinidene complex in 2020. In these more than ten years of research, we have also found some interesting reactivity of the rare-earth metal phosphinidene complexes. The rare-earth metal bridging phosphinidene complexes can act as two-electron reductants based on the oxidative coupling of two phosphinidene ligands into a diphosphene ligand. The mononuclear rare-earth metal phosphinidene complexes catalyze the hydrogenation of terminal alkenes under mild conditions, and the joint experimental/DFT studies indicate that the hydrogenation reaction proceeds in a 1,2-addition/elimination mechanism rather than the common σ-bond metathesis mechanism. These reactivities are new and important for the rare-earth metal complexes. In addition, the ligand design in our study may contribute to the synthesis of rare-earth metal-arsenic multiple bonding complexes and alkaline-earth metal-phosphorus multiple bonding complexes, which have not yet been realized. Herein, we present an account of our investigations into rare-earth metal phosphinidene complexes, a trip from bridging one to terminal one. To give the readers an overall image of the development of the rare-earth metal phosphinidene complexes, some findings from other researchers are also included.

Thermal Stability, Optical and Electrical Properties of Substoichiometric Molybdenum Oxide.

Substoichiometric molybdenum oxide ceramics have aroused widespread interest owing to their promising optical and electrical performance. In this work, the thermal stability and decomposition mechanism of Mo9O26 and Mo4O11 at 700-1000 °C and 700-1100 °C were investigated, respectively. Based on this information, MoOx (2 < x < 3) bulk ceramics were prepared by spark plasma sintering (SPS). The results show that Mo9O26 is stable up to 790 °C in an argon atmosphere. As the temperature rises, it decomposes into Mo4O11. Mo4O11 can exist stably at 830 °C, beyond which it will convert to MoO2. The MoOx ceramic bulks with four different components (MoO2.9, MoO2.8, MoO2.7 and MoO2.6) were successfully sintered by SPS, and their relative density was greater than 96.4% as measured by the Archimedes principle. The reflectivity of MoOx ceramic bulk is low and only 6.3% when the composition is MoO2.8. The resistivity increases from 10-3 to 10-1 Ωcm with the increase in the O/Mo atomic ratio x. In general, the thermal stability information provides a theoretical basis for the processing of MoOx materials, such as the sintering of the MoOx target. The optical and electrical properties show that MoOx is a low-reflective conductive oxide material with great photoelectric application value.

Organocalcium-Complex-Catalyzed Dehydrogenative Silylation and Mono/Dihydrosilylation Tandem Reactions of Terminal Alkynes.

In principle, catalytic dehydrogenative silylation and mono/dihydrosilylation tandem reactions of terminal alkynes with hydrosilanes provide gem-disilylated alkenes or gem-trisilylated alkanes, but very little progress has been made. Herein, we report organocalcium-complex-catalyzed dehydrogenative silylation and mono/dihydrosilylation tandem reactions of terminal alkynes with hydrosilanes in one pot, which produce gem-disilylated alkenes in moderate yields and gem-trisilylated alkanes in high yields. We also briefly demonstrate that the synthesized gem-disilylated alkenes can be easily transformed into other organosilanes.

Imidazolin-2-iminato Cerium(IV) Chlorides: Synthesis, Structure and Electrochemical Properties.

The ligand field greatly affects the redox properties of cerium. Herein, cerium(III) and cerium(IV) complexes supported by imidazolin-2-iminato ligands were synthesized and structurally characterized, and their electrochemical properties were investigated. Silylamine elimination of cerium(III) amide Ce{N(SiMe3 )2 }3 with imidazolin-2-imine ImR NH (R=Mes, tBu, iPr) provided imidazolin-2-iminato cerium(III) complexes, [(ImMes N)(ImMes NH)Ce{N(SiMe3 )2 }2 ] (1), [(ImtBu N)2 (ImtBu NH)Ce{N(SiMe3 )2 }] (2) and [(ImiPr N)2 (ImiPr NH)Ce(µ-ImiPr N)]2 (4) in 71-85% yields. These cerium(III) complexes were successfully oxidized by Ph3 CCl or C2 Cl6 to afford imidazolin-2-iminato cerium(IV) chlorides, [(ImMes N)2 Ce{N(SiMe3 )2 }Cl] (5), [(ImtBu N)3 CeCl] (6) and [(ImiPr N)2 Ce(µ-ImiPr N)Cl]2 (7) in 70%-76% yields. All complexes were characterized by the single-crystal X-ray diffraction, which showed that 1, 2, 5 and 6 are monomers while 4 and 7 are dimers. The electrochemical studies indicated that the Ce(III/IV) couples for 5 and 6 are more negative than those of silylamido cerium(IV) complexes, and the Ce(III/IV) couples for 1 and 2 have a similar trend.

Synthesis, Characterization, and Reactivity of a Hydrido- and Imido-Bridged Dinuclear Ytterbium(III) Complex.

The trivalent rare-earth metal hydrido and imido complexes are of versatile reactivity, and many such complexes have been synthesized. However, no example of a rare-earth metal complex bearing both hydrido- and imido-ligands has been reported. Herein, we report the first rare-earth metal complex bearing both hydrido- and imido-ligands, namely a hydrido- and imido-bridged dinuclear ytterbium(III) complex. The complex was synthesized via an unprecedented redox reaction of divalent rare-earth metal hydrido complex with azido compound. DFT calculation indicated that the N2 release from azido compound in the presence of ytterbium(II) is a kinetically facile process because of the cooperative effects of the two metal centers. The reactivity of the hydrido- and imido-bridged dinuclear ytterbium(III) complex was also explored, which showed the redox, addition and σ-bond metathesis reactivities.

Tomato SlCER1-1 catalyzes the synthesis of wax alkanes which increases the drought tolerance and fruit storability.

Very-long-chain (VLC) alkanes are the main wax compounds of tomato fruit and leaf. ECERIFERUM1 (CER1) and ECERIFERUM3 (CER3) are the two key genes involved in VLC alkane biosynthesis in Arabidopsis thaliana. However, the CER1 and CER3 homologous genes in tomato have not been investigated and their exact biological function remains unknown. We analyzed the wax profiles in tomato leaves and fruits at different growth stages, and characterized the CER1 and CER3 homologous genes. VLC alkanes were the predominant wax compounds both in the leaf and fruit at all developmental stages. We identified five CER1 homologs and two CER3 homologs in tomato, which were designated as SlCER1-1 to SlCER1-5 and SlCER3-1 and SlCER3-2 respectively. The genes exhibited tissue- and organ-dependent expression patterns and were induced by abiotic stresses. SlCER1-1 was localized to the endoplasmic reticulum (ER), which is also the main site of wax biosynthesis. Silencing the SlCER1-1 gene in tomato significantly reduced the amounts of n-Alkanes and branched alkanes, whereas its overexpression in Arabidopsis had the opposite effect. Under drought stress, both n-Alkanes and branched alkanes increased significantly in wild-type but not the SlCER1-1 RNAi tomato plants. Furthermore, SlCER1-1 silencing also increased the cuticular permeabilities of the leaves and fruits. In conclusion, SlCER1-1 is involved in wax alkane biosynthesis in tomato and plays an important role in the drought tolerance and fruit storability.

Identification of a Long Noncoding RNA (lncPRDM16) Inhibiting Preadipocyte Proliferation in the Chicken.

Long noncoding RNAs are vital to a variety of biological and physiological processes through multiple modes of functional interaction with DNA, RNA, and proteins. In chickens, numerous lncRNAs were discovered to be important to growth or disease progression. However, the detailed molecular function and role of lncRNAs remain less explored. Here, we performed lncRNA sequencing on abdominal adipose tissues from broiler lines divergently selected for abdominal fat content, and significantly differentially expressed lncRNAs were found, including lncPRDM16, a divergently transcribed and conserved lncRNA near PRDM16. Full lengths of two transcripts of lncPRDM16 were obtained, and their genomic structures were compared. Expression dynamics of lncPRDM16 in different tissues and during preadipocyte proliferation and differentiation were profiled. Moreover, a 250-nucleotide sequence at 5'-end was found to be inevitable to the function of lncPRDM16 in inhibiting preadipocyte proliferation and regulating the promoter activities of both lncPRDM16 and PRDM16. Taken together, we identified the 5'-end functional elements of lncPRDM16 and their potential importance in inhibiting preadipocyte proliferation. Our findings provide the foundation for further exploration of lncPRDM16 function and potential improvement of chicken muscle quality.

Divalent Ytterbium Hydrido Complex Supported by a ß-Diketiminato-Based Tetradentate Ligand: Synthesis, Structure, and Reactivity.

While the chemistry of trivalent rare-earth metal hydrido complexes has been well developed in the past 40 years, that of the divalent rare-earth metal hydrido complexes remains in its infancy because of the synthetic challenge of such complexes. In this paper, we report the synthesis and structural characterization of a divalent ytterbium hydrido complex supported by a bulky ß-diketiminato-based tetradentate ligand. This hydrido complex is a dimer containing two µ-hydrogen ligands, and it easily undergoes a hydrido shift reaction to form a new divalent ytterbium hydrido complex that contains only one hydrido bridge. Furthermore, this hydrido complex reacts with pyridine and pyridine derivatives, showing versatile reactivity [Yb-H addition to pyridine, hydrido shift to ancillary ligand, and ytterbium(II)-center-induced redox reaction with bipyridine]. This hydrido complex reacts with Ph3P═O, resulting in a P-CPh cleavage of Ph3P═O and an elimination of C6H6; on the other hand, the reaction with Ph3P═S is a hydrido coupling-based redox reaction. The reactions of this hydrido complex with 1 and 2 equiv of PhSSPh clearly indicate that the hydrido coupling-based redox reaction is prior to the ytterbium(II) oxidation-based redox reaction.

Scandium-Terminal Boronylphosphinidene Complex.

The first isolation and structural characterization of a rare-earth metal-terminal imido complex were reported in 2010, but a rare-earth metal-terminal phosphinidene complex is still absent, to date. Herein, we report the synthesis and structure of the first example of a rare-earth-terminal phosphinidene complex, namely the scandium boronylphosphinidene complex. Single-crystal X-ray diffraction shows that the complex has a much shorter Sc-P bond length as compared to that in a related scandium boronylphosphido complex, 2.381(1) Å vs 2.564(1) Å. DFT calculations indicate the presence of a strong Sc-P π interaction in this complex, which is in striking contrast to the weak interaction found in the phosphido complex. A preliminary reactivity study demonstrates that the scandium-terminal boronylphosphinidene complex behaves as a nucleophilic phosphinidene complex.

Insertion of Metal-Substituted Silylene into Naphthalene's Aromatic Ring and Subsequent Rearrangement for Silaspiro-Benzocycloheptenyl and Cyclobutenosilaindan Derivatives.

Synthesis of silacycle compounds are of fundamental and application importance. Herein we report the first example of insertion of metal-substituted silylene fragment into naphthalene's aromatic ring. More significantly, this insertion is followed by interesting rearrangements to yield silaspiro-benzocycloheptenyl and cyclobutenosilaindan derivatives. The formation of cyclobutenosilaindan derivative includes the C-C bond cleavage and 4π electrocyclization steps; the formation of silaspiro-benzocycloheptenyl derivative is more complicated, including the C-C bond cleavage, reversible 4π electrocyclization, C-H bond activation and C-Si bond cleavage. DFT investigations were carried out to shed light on the mechanistic aspects of these two rearrangements. The formed cyclobutenosilaindan potassium can readily react with PhOH, MeOTf, EtOTf, PhCH2 Cl or PhCOCl at room temperature to afford the hydrogen, alkyl, benzyl or benzoyl substituted cyclobutenosilaindans in high yields.

Synthesis and versatile reactivity of scandium phosphinophosphinidene complexes.

M=E/M≡E multiple bonds (M = transition metal, E = main group element) are of significant fundamental scientific importance and have widespread applications. Expanding the ranges of M and E represents grand challenges for synthetic chemists and will bring new horizons for the chemistry. There have been reports of M=E/M≡E multiple bonds for the majority of the transition metals, and even some actinide metals. In stark contrast, as the largest subgroup in the periodic table, rare-earth metals (Ln) were scarcely involved in Ln=E/Ln≡E multiple bonds. Until recently, there were a few examples of rare-earth monometallic alkylidene, imido and oxo complexes, featuring Ln=C/N/O bonds. What are in absence are rare-earth monometallic phosphinidene complexes with Ln=P bonds. Herein, we report synthesis and structure of rare-earth monometallic phosphinidene complexes, namely scandium phosphinophosphinidene complexes. Reactivity of scandium phosphinophosphinidene complexes is also mapped out, and appears to be easily tuned by the supporting ligand.

Common Gene Modules Identified for Chicken Adiposity by Network Construction and Comparison.

Excessive fat deposition can cause chicken health problem, and affect production efficiency by causing great economic losses to the industry. However, the molecular underpinnings of the complex adiposity trait remain elusive. In the current study, we constructed and compared the gene co-expression networks on four transcriptome profiling datasets, from two chicken lines under divergent selection for abdominal fat contents, in an attempt to dissect network compositions underlying adipose tissue growth and development. After functional enrichment analysis, nine network modules important to adipogenesis were discovered to be involved in lipid metabolism, PPAR and insulin signaling pathways, and contained hub genes related to adipogenesis, cell cycle, inflammation, and protein synthesis. Moreover, after additional functional annotation and network module comparisons, common sub-modules of similar functionality for chicken fat deposition were identified for different chicken lines, apart from modules specific to each chicken line. We further validated the lysosome pathway, and found TFEB and its downstream target genes showed similar expression patterns along with chicken preadipocyte differentiation. Our findings could provide novel insights into the genetic basis of complex adiposity traits, as well as human obesity and related metabolic diseases.

Samarium(II) Monoalkyl Complex Supported by a ß-Diketiminato-Based Tetradentate Ligand: Synthesis, Structure, and Catalytic Hydrosilylation of Internal Alkynes.

The synthesis and catalytic applications of trivalent rare-earth metal alkyl complexes have been well developed, but the chemistry of divalent rare-earth metal alkyl complexes lagged much behind. Herein, we report the synthesis, structure, and catalytic applications of a samarium(II) monoalkyl complex supported by a ß-diketiminato-based tetradentate ligand, [LSmCH(SiMe3 )2 ] (L=[MeC(NDipp)CHC(Me)NCH2 CH2 N(Me)CH2 CH2 NMe2 ]- , Dipp=2,6-(iPr)2 C6 H3 ). This complex is synthesized by the salt metathesis reaction of samarium iodide [LSm(µ-I)]2 and KCH(SiMe3 )2 in 63 % yield. Its structure is characterized by single-crystal X-ray diffraction, showing a distorted square-pyramid coordination geometry. This samarium(II) monoalkyl complex exhibits high catalytic activity in the hydrosilylation of aryl and methyl-substituted unsymmetrical internal alkynes with secondary hydrosilanes, selectively providing the α-(E) products in high yields.

Expression Analysis and Functional Characterization of CER1 Family Genes Involved in Very-Long-Chain Alkanes Biosynthesis in Brachypodium distachyon.

Cuticular wax accumulation and composition affects drought resistance in plants. Brachypodium distachyon plants subjected to water deficit and polyethylene glycol treatments resulted in a significant increase in total wax load, in which very-long-chain (VLC) alkanes were more sensitive to these treatments than other wax compounds, implying that VLC alkanes biosynthesis plays a more important role in drought resistance in B. distachyon. ECERIFERUM1 (CER1) has been reported to encode a core enzyme involved in VLC alkanes biosynthesis in Arabidopsis (Arabidopsis thaliana), but few corresponding genes are investigated in B. distachyon. Here, we identified eight CER1 homologous genes in B. distachyon, namely BdCER1-1 to BdCER1-8, and then analyzed their sequences feature, expression patterns, stress induction, and biochemical activities. These genes had similar protein structure to other reported CER1 and CER1-like genes, but displayed closer phylogenetic relationship to the rice OsGL1 genes. They were further found to exhibit various tissue expression patterns after being induced by abiotic stresses. Among them, BdCER1-8 gene showed extremely high expression in leaves. Heterologous introduction of BdCER1-8 into the Arabidopsis cer1 mutant rescued VLC alkanes biosynthesis. These results indicate that BdCER1 genes are likely to be involved in VLC alkanes biosynthesis of B. distachyon. Taken together, BdCER1-8 seems to play an explicit and predominant role in VLC alkanes biosynthesis in leaf. Our work provides important clues for further characterizing function of CER1 homologous genes in B. distachyon and also an option to improve drought resistance of cereal crops.

Functional Intronic Variant in the Retinoblastoma 1 Gene Underlies Broiler Chicken Adiposity by Altering Nuclear Factor-kB and SRY-Related HMG Box Protein 2 Binding Sites.

The present study aimed to search for chicken abdominal fat deposition-related polymorphisms within RB1 and to provide functional evidence for significantly associated genetic variants. Association analyses showed that 11 single nucleotide polymorphisms (SNPs) in intron 17 of RB1, were significantly associated with both abdominal fat weight (P < 0.05) and abdominal fat percentage (P < 0.05). Functional analysis revealed that the A allele of g.32828A>G repressed the transcriptional efficiency of RB1 in vitro, through binding nuclear factor-kappa B (NF-KB) and SRY-related HMG box protein 2 (SOX2). Furthermore, RB1 mRNA expression levels in the abdominal fat tissue of individuals with the A/A genotype of g.32828A>G were lower than those of individuals with the G/G genotype. Collectively, we propose that the intronic SNP g.32828A>G of RB1 is an obesity-associated variant that directly affects binding with NF-KB and SOX2, leading to changes in RB1 expression which in turn may influence chicken abdominal fat deposition.

Rare-earth/zinc heterometallic complexes containing both alkoxy-amino-bis(phenolato) and chiral salen ligands: synthesis and catalytic application for copolymerization of CO2 with cyclohexene oxide.

Ten rare-earth/zinc heterometallic complexes containing both alkoxy-amino-bis(phenolato) and chiral salen ligands were synthesized from the reactions of alkoxy-amino-bis(phenolato) rare-earth complexes with chiral salen zinc complexes via ligand redistribution and THF disassociation. Six of them were characterized by single-crystal X-ray diffraction, which showed 6-coordinate rare-earth and 5-coordinate zinc centres in the complexes. A primary catalytic application of these heterometallic complexes was studied, and it was found that samarium/zinc and dysprosium/zinc heterometallic complexes are highly efficient catalysts for copolymerization of CO2 with cyclohexene oxide while the alkoxy-amino-bis(phenolato) samarium complex and chiral salen zinc complex show very low catalytic activity or no catalytic activity for this copolymerization.

Neutral and Anionic Monomeric Zirconium Imides Prepared via Selective C=N Bond Cleavage of a Multidentate and Sterically Demanding ß-Diketiminato Ligand.

A sterically encumbering multidentate ß-diketiminato ligand, tBu L2 (tBu L2=[ArNC(tBu)CHC(tBu)NCH2 CH2 N(Me)CH2 CH2 NMe2 ]- , Ar=2,6-iPr2 C6 H3 ), is reported in this study along with its coordination chemistry to zirconium(IV). Using the lithio salt of this ligand, Li(tBu L2) (4), the zirconium(IV) precursor (tBu L2)ZrCl3 (6) could be readily prepared in 85 % yield and structurally characterized. Reduction of 6 with 2 equiv of KC8 resulted in formation of the terminal and mononuclear zirconium imide-chloride [C(tBu)CHC(tBu)NCH2 CH2 N(Me)CH2 CH2 NMe2 ]Zr(=NAr)(Cl) (7) as the result of reductive C=N cleavage of the imino fragment in the multidentate ligand tBu L2 by an elusive ZrII species (tBu L2)ZrCl (A). The azabutadienyl ligand in 7 can be further reduced by 2 e- with KC8 to afford the anionic imide [K(THF)2 ]{[CH(tBu)CHC(tBu)NCH2 CH2 N(Me)CH2 CH2 N(Me)CH2 ]Zr=NAr} (8-2THF) in 42 % isolated yield. Complex 8-2THF results from the oxidative addition of an amine C-H bond followed by migration to the vinylic group of the formal [C(tBu)CHC(tBu)NCH2 CH2 N(Me)CH2 CH2 NMe2 ]- ligand in 7. All halides in 6 can be replaced with azides to afford (tBu L2)Zr(N3 )3 (9) which was structurally characterized, and reduction with two equiv of KC8 also results in C=N bond cleavage of tBu L2 to form [C(tBu)CHC(tBu)NCH2 CH2 N(Me)CH2 CH2 NMe2 ]Zr(=NAr)(N3 ) (10), instead of the expected azide disproportionation to N3- and N2 . Solid-state single crystal structural studies confirm the formation of mononuclear and terminal zirconium imido groups in 7, 8-Et2 O, and 10 with Zr=NAr distances being 1.8776(10), 1.9505(15), and 1.881(3) Å, respectively.