Association Between Sarcopenia, Clinical Outcomes, and Survival in Patients with Extensive-Stage Small Cell Lung Cancer Treated with First-Line Immunochemotherapy: A Prospective Cohort Study.

OBJECTIVE: To investigate the association between sarcopenia, short-term efficacy, and long-term survival in patients with extensive small-cell lung cancer (SCLC) treated with standard first-line immunochemotherapy. METHODS: A total of 63 patients initially diagnosed with extensive-stage small cell lung cancer were enrolled in the prospective study from December 1, 2020 to December 31, 2022. The clinical characteristics, body composition, blood test results, and image data were obtained before treatment. Patients were divided into sarcopenia and non-sarcopenia groups according to the diagnostic criteria of the Asian Sarcopenia Working Group 2019. The primary outcome was overall survival (OS) and comprehensive survival analyses were performed. Secondary outcomes included short-term efficacy and adverse events associated with first-line immunochemotherapy. RESULTS: The median age of the 63 patients enrolled in our study was 63.0 years (40-80 years). The incidence of sarcopenia was 19.0% (12/63) in patients with extensive SCLC. Compared with non-sarcopenia patients, extensive-stage SCLC patients with sarcopenia were significantly older (69.0 vs. 62.0, P = 0.017), and had lower body mass index (BMI) (20.29 vs. 24.27, P < 0.001), hand grip strength (HGS) (20.42 vs. 30.75, P < 0.001), and albumin (35.9 vs. 41.40, P < 0.001). The objective response rate after two cycles of standard first-line immunochemotherapy in the sarcopenia group was lower than in the non-sarcopenia group (30.0 vs. 78.9%, P = 0.012). There was no significant difference in chemotherapy-related hematological toxicity between the two groups. During a median follow-up of 15 months (3-33 months), patients with extensive SCLC had a median OS of 24 months, with 1-year survival of 75% and 2-year survival of 52%, respectively. Compared to non-sarcopenia patients, the median OS in the sarcopenia group was significantly shorter (9 vs. 24 months, P = 0.0014). Multivariate Cox analysis showed that sarcopenia was an independent risk factor for OS in patients with extensive SCLC (HR = 4.993, 95%CI = 1.106-22.538, P = 0.037). CONCLUSIONS: Patients with Extensive SCLC and sarcopenia had worse clinical outcomes and shorter OS. Sarcopenia is a prognostic factor affecting first-line treatment efficacy and long-term survival of patients with SCLC in the era of immunotherapy.

Enhanced interleukin-16-CD4 signaling in CD3 T cell mediates neuropathic pain via activating astrocytes in female mice.

Immune cells and interleukins play a crucial role in female-specific pain signaling. Interleukin 16 (IL-16) is a cytokine primarily associated with CD4+ T cell function. While previous studies have demonstrated the important role of spinal CD4+ T cells in neuropathic pain, the specific contribution of IL-16 to neuropathic pain remains unclear. In this study, by using a spinal nerve ligation (SNL)-induced neuropathic pain mice model, we found that SNL induced an increase in IL-16 mRNA levels, which persisted for a longer duration in female mice compared to male mice. Immunofluorescence analysis further confirmed enhanced IL-16- and CD4-positive signals in the spinal dorsal horn following SNL surgery in female mice. Knockdown of spinal IL-16 by siRNA or inhibition of CD4 by FGF22-IN-1, a CD4 inhibitor, attenuated established mechanical and thermal pain hypersensitivity induced by SNL. Furthermore, female mice injected with IL-16 intrathecally exhibited significant spontaneous pain, mechanical and thermal hyperalgesia, all of which could be alleviated by FGF22-IN-1 or a CD3 antibody. Additionally, IL-16 induced astrocyte activation but not microglial activation in the spinal dorsal horn of female mice. Meanwhile, astrocyte activation could be suppressed by the CD3 antibody. These results provide compelling evidence that IL-16 promotes astrocyte activation via CD4 on CD3+ T cells, which is critical for maintaining neuropathic pain in female mice.

A novel antimicrobial peptide S24 combats serious wound infections caused by Pseudomonas aeruginosa and Acinetobacter baumannii.

OBJECTIVES: Pseudomonas aeruginosa and Acinetobacter baumannii are ranked as top-priority organisms by WHO. Antimicrobial peptides (AMPs) are promising antimicrobial agents that are highly effective against serious bacterial infections. METHODS: In our previous study, a series of α-helical AMPs were screened using a novel multiple-descriptor strategy. The current research suggested that S24 exhibited strong antimicrobial activity against major pathogenic bacteria, and displayed minimal haemolysis, good serum stability and maintained salt resistance. RESULTS: We found that S24 exerted an antimicrobial effect by destroying outer membrane permeability and producing a strong binding effect on bacterial genomic DNA that inhibits genomic DNA migration. Furthermore, S24 exerted a strong ability to promote healing in wound infected by P. aeruginosa, A. baumannii and mixed strains in a mouse model. CONCLUSIONS: Overall, S24 showed good stability under physiological conditions and excellent antimicrobial activity, suggesting it may be a potential candidate for the development of serious bacterial infection treatment.

CircNSD1 promotes cardiac fibrosis through targeting the miR-429-3p/SULF1/Wnt/ß-catenin signaling pathway.

Cardiac fibrosis is a detrimental pathological process, which constitutes the key factor for adverse cardiac structural remodeling leading to heart failure and other critical conditions. Circular RNAs (circRNAs) have emerged as important regulators of various cardiovascular diseases. It is known that several circRNAs regulate gene expression and pathological processes by binding miRNAs. In this study we investigated whether a novel circRNA, named circNSD1, and miR-429-3p formed an axis that controls cardiac fibrosis. We established a mouse model of myocardial infarction (MI) for in vivo studies and a cellular model of cardiac fibrogenesis in primary cultured mouse cardiac fibroblasts treated with TGF-ß1. We showed that miR-429-3p was markedly downregulated in the cardiac fibrosis models. Through gain- and loss-of-function studies we confirmed miR-429-3p as a negative regulator of cardiac fibrosis. In searching for the upstream regulator of miR-429-3p, we identified circNSD1 that we subsequently demonstrated as an endogenous sponge of miR-429-3p. In MI mice, knockdown of circNSD1 alleviated cardiac fibrosis. Moreover, silence of human circNSD1 suppressed the proliferation and collagen production in human cardiac fibroblasts in vitro. We revealed that circNSD1 directly bound miR-429-3p, thereby upregulating SULF1 expression and activating the Wnt/ß-catenin pathway. Collectively, circNSD1 may be a novel target for the treatment of cardiac fibrosis and associated cardiac disease.

Multicomponent nickel-molybdenum-tungsten-based nanorods for stable and efficient alkaline seawater splitting.

The electrolysis of seawater for hydrogen production holds promise as a sustainable technology for energy generation. Developing water-splitting catalysts with low overpotential and stable operation in seawater is essential. In this study, we employed a hydrothermal method to synthesize NiMoWOX microrods (NiMoWOX@NF). Subsequently, an annealing process yielded a composite N-doped carbon-coated Ni3N/MoO2/WO2 nanorods (NC@Ni3N/MoO2/WO2@NF), preserving the ultrahigh-specific surface area of the original structure. A two-electrode electrolytic cell was assembled using NC@Ni3N/MoO2/WO2@NF as the cathode and NiMoWOX@NF as the anode, demonstrating exceptional performance in seawater splitting. The cell operated at a voltage of 1.51 V with a current density of 100 mA·cm-2 in an alkaline seawater solution. Furthermore, the NC@Ni3N/MoO2/WO2@NF || NiMoWOX@NF electrolytic cell exhibited remarkable stability, running continuously for over 120 h at a current of 1100 mA·cm-2 without any observable delay. These experimental results are corroborated by density functional theory calculations. The NC@Ni3N/MoO2/WO2@NF || NiMoWOX@NF electrolyzer emerges as a promising option for industrial-scale hydrogen production through seawater electrolysis.

Spinal interleukin-16 mediates inflammatory pain via promoting glial activation.

Proinflammatory cytokines are crucial contributors to neuroinflammation in the development of chronic pain. Here, we identified il16, which encodes interleukin-16 (IL-16), as a differentially expressed gene in spinal dorsal horn of a complete Freund's Adjuvant (CFA) inflammatory pain model in mice by RNA sequencing. We further investigated whether and how IL-16 regulates pain transmission in the spinal cord and contributes to the development of inflammatory pain hypersensitivity. RNA sequencing and bioinformatics analysis revealed elevated IL-16 transcript levels in the spinal dorsal horn after CFA injection. This increase was further confirmed by qPCR, immunofluorescence, and western blotting. Knockdown of IL-16 by intrathecal injection of IL-16 siRNA not only attenuated CFA-induced mechanical and thermal pain hypersensitivity, but also inhibited enhanced c-fos expression and glial activation in the spinal dorsal horn in male mice injected with CFA. Moreover, exogenous IL-16 induced nociceptive responses and increased c-fos expression and glial activation in spinal dorsal horn. This effect was largely impaired when CD4, the binding receptor for IL-16, was inhibited. In addition, CD4 expression was upregulated in the spinal dorsal horn after CFA injection and CD4 was present in microglia and in contact with astrocytes and activated spinal neurons. Taken together, these results suggest that enhanced IL-16-CD4 signaling triggers pain and activates microglia and astrocytes in the spinal dorsal horn, thus contributing to inflammatory pain. IL-16 may serve as a promising target for the treatment of inflammatory pain.

Neurodevelopmental toxicity induced by PM2.5 Exposure and its possible role in Neurodegenerative and mental disorders.

Recent extensive evidence suggests that ambient fine particulate matter (PM2.5, with an aerodynamic diameter ≤2.5 µm) may be neurotoxic to the brain and cause central nervous system damage, contributing to neurodevelopmental disorders, such as autism spectrum disorders, neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, and mental disorders, such as schizophrenia, depression, and bipolar disorder. PM2.5 can enter the brain via various pathways, including the blood-brain barrier, olfactory system, and gut-brain axis, leading to adverse effects on the CNS. Studies in humans and animals have revealed that PM2.5-mediated mechanisms, including neuroinflammation, oxidative stress, systemic inflammation, and gut flora dysbiosis, play a crucial role in CNS damage. Additionally, PM2.5 exposure can induce epigenetic alterations, such as hypomethylation of DNA, which may contribute to the pathogenesis of some CNS damage. Through literature analysis, we suggest that promising therapeutic targets for alleviating PM2.5-induced neurological damage include inhibiting microglia overactivation, regulating gut microbiota with antibiotics, and targeting signaling pathways, such as PKA/CREB/BDNF and WNT/ß-catenin. Additionally, several studies have observed an association between PM2.5 exposure and epigenetic changes in neuropsychiatric disorders. This review summarizes and discusses the association between PM2.5 exposure and CNS damage, including the possible mechanisms by which PM2.5 causes neurotoxicity.

[CircRNA-0028171 regulates arsenic trioxide-induced apoptosis in vascular endothelial cells].

The present study was aimed to investigate the effects of circRNA-0028171 on the apoptosis of vascular endothelial cells induced by arsenic trioxide (As2O3). Human umbilical vein endothelial cells (HUVECs) were treated with 0-15 µmol/L As2O3 for 24 h. Then, cellular viability was measured by MTT assay. The expression levels of circRNA-0028171, Bcl-2 and Bax mRNA were detected by real-time quantitative PCR. Bcl-2/Bax protein ratio was detected by Western blot. Whether circRNA-0028171 was involved in the regulation of HUVECs by As2O3 was investigated by transfection with overexpression plasmid of circRNA-0028171 and siRNA. The results showed that compared with the control group, As2O3 group showed decreased cellular viability, reduced Bcl-2/Bax mRNA and protein ratios, and significantly lower expression of circRNA-0028171. Overexpression of circRNA-0028171 inhibited apoptosis of HUVECs induced by As2O3. Knockdown of circRNA-0028171 by siRNA promoted As2O3-induced apoptosis in HUVECs. These results suggest that circRNA-0028171 is involved in the vascular endothelial cell apoptosis induced by As2O3.

Target identification of anti-diabetic and anti-obesity flavonoid derivative (Fla-CN).

Fla-CN is a flavonoid derivative with anti-diabetic and anti-obesity effects; however, its biological targets are still unknown. In this study, we developed bifunctional affinity-based probes to identify the direct targets of Fla-CN. When using probe 3, we observed the co-location of probe 3 and mitochondria in both HepG2 and 3T3-L1 cells. The putative target proteomes were obtained using activity-based protein profiling (ABPP) and photo-affinity labelling. Pyruvate carboxylase, mitochondrial malate dehydrogenase, mitochondrial complex I, and F1FO-ATPase were validated as the direct targets of Fla-CN by surface plasmon resonance (SPR) and biochemical assays. It was elucidated that the Tyr651, Gln870 and Lys912 were the key amino acid residues near the binding site of pyruvate carboxylase with Fla-CN. The direct interaction of Fla-CN and the above four targets allowed elucidation of its complicated molecular mechanism, including the activation of adenosine 5-monophosphate (AMP)-activated protein kinase (AMPK), and the inhibition of gluconeogenesis. Further investigation for activation of AMPK in normal and insulin resistance (IR) HepG2 cells, indicated that Fla-CN could target insulin resistance tissues.

A non-canonical binding interface in the crystal structure of HIV-1 gp120 core in complex with CD4.

Numerous crystal structures of HIV gp120 have been reported, alone or with receptor CD4 and cognate antibodies; however, no sole gp120/CD4 complex without stabilization by an antibody is available. Here, we report a crystal structure of the gp120/CD4 complex without the aid of an antibody from HIV-1 CRF07_BC, a strain circulating in China. Interestingly, in addition to the canonical binding surface, a second interacting interface was identified. A mutagenesis study on critical residues revealed that the stability of this interface is important for the efficiency of Env-mediated membrane fusion. Furthermore, we found that a broad neutralizing antibody, ibalizumab, which targets CD4 in the absence of gp120, occupies the same binding surface as the second interface identified here on gp120. Therefore, we identified the possibility of the involvement of a second gp120-CD4 interaction interface during viral entry, and also provided a reasonable explanation for the broad activity of neutralizing antibody ibalizumab.

Tissue-Specific Regulation of the Contents and Correlations of Mineral Elements in Hens by Zinc Oxide Nanoparticles.

Due to their small size, zinc oxide (ZnO) nanoparticles (NPs) are readily absorbed and easily cross biological barriers, which make them promising candidates as diet additives. However, some studies have reported that ZnO NPs cause toxicity; therefore, their safety and potency as diet additives for farm animals should be established. This study was the first to fully evaluate the effects of ZnO NPs on the homeostasis of eight elements in seven organs/tissues. The regulation of element homeostasis was found to be organ specific with no influence on oxidation status, anti-oxidation capability, or organ damage. ZnO NPs may specifically regulate the homeostasis of mineral elements and affect the following correlations: (1) between the element content in each organ and the concentration of Zn used in ZnSO4 or ZnO NP treatments; (2) between ZnO NP and ZnSO4 treatments for the same element in each organ; and (3) between elements (in each organ in ZnSO4 or ZnO NP treatments) in layers' organs/tissues. The use of ZnO NPs as diet additives for animals should be implemented cautiously because, among other uncertainties, they may affect mineral element content.

Hydrogen Sulfide and/or Ammonia Reduces Spermatozoa Motility through AMPK/AKT Related Pathways.

A number of emerging studies suggest that air pollutants such as hydrogen sulfide (H2S) and ammonia (NH3) may cause a decline in spermatozoa motility. The impact and underlying mechanisms are currently unknown. Boar spermatozoa (in vitro) and peripubertal male mice (in vivo) were exposed to H2S and/or NH3 to evaluate the impact on spermatozoa motility. Na2S and/or NH4Cl reduced the motility of boar spermatozoa in vitro. Na2S and/or NH4Cl disrupted multiple signaling pathways including decreasing Na+/K+ ATPase activity and protein kinase B (AKT) levels, activating Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and phosphatase and tensin homolog deleted on chromosome ten (PTEN), and increasing reactive oxygen species (ROS) to diminish boar spermatozoa motility. The increase in ROS might have activated PTEN, which in turn diminished AKT activation. The ATP deficiency (indicated by reduction in Na+/K+ ATPase activity), transforming growth factor (TGFß) activated kinase-1 (TAK1) activation, and AKT deactivation stimulated AMPK, which caused a decline in boar spermatozoa motility. Simultaneously, the deactivation of AKT might play some role in the reduction of boar spermatozoa motility. Furthermore, Na2S and/or NH4Cl declined the motility of mouse spermatozoa without affecting mouse body weight gain in vivo. Findings of the present study suggest that H2S and/or NH3 are adversely associated with spermatozoa motility.

Regulation of neuroendocrine cells and neuron factors in the ovary by zinc oxide nanoparticles.

The pubertal period is an important window during the development of the female reproductive system. Development of the pubertal ovary, which supplies the oocytes intended for fertilization, requires growth factors, hormones, and neuronal factors. It has been reported that zinc oxide nanoparticles (ZnO NPs) cause cytotoxicity of neuron cells. However, there have been no reports of the effects of ZnO NPs on neuronal factors and neuroendocrine cells in the ovary (in vivo). For the first time, this in vivo study investigated the effects of ZnO NPs on gene and protein expression of neuronal factors and the population of neuroendocrine cells in ovaries. Intact NPs were detected in ovarian tissue and although ZnO NPs did not alter body weight, they reduced the ovary organ index. Compared to the control or ZnSO4 treatments, ZnO NPs treatments differentially regulated neuronal factor protein and gene expression, and the population of neuroendocrine cells. ZnO NPs changed the contents of essential elements in the ovary; however, they did not alter levels of the steroid hormones estrogen and progesterone. These data together suggest that intact ZnO NPs might pose a toxic effect on neuron development in the ovary and eventually negatively affect ovarian developmental at puberty.

Regulation of MicroRNAs, and the Correlations of MicroRNAs and Their Targeted Genes by Zinc Oxide Nanoparticles in Ovarian Granulosa Cells.

Zinc oxide (ZnO) nanoparticles (NPs) have been applied in numerous industrial products and personal care products like sunscreens and cosmetics. The released ZnO NPs from consumer and household products into the environment might pose potential health issues for animals and humans. In this study the expression of microRNAs and the correlations of microRNAs and their targeted genes in ZnO NPs treated chicken ovarian granulosa cells were investigated. ZnSO4 was used as the sole Zn2+ provider to differentiate the effects of NPs from Zn2+. It was found that ZnO-NP-5 µg/ml specifically regulated the expression of microRNAs involved in embryonic development although ZnO-NP-5 µg/ml and ZnSO4-10 µg/ml treatments produced the same intracellular Zn concentrations and resulted in similar cell growth inhibition. And ZnO-NP-5 µg/ml also specifically regulated the correlations of microRNAs and their targeted genes. This is the first investigation that intact NPs in ZnO-NP-5 µg/ml treatment specifically regulated the expression of microRNAs, and the correlations of microRNAs and their targeted genes compared to that by Zn2+. This expands our knowledge for biological effects of ZnO NPs and at the same time it raises the health concerns that ZnO NPs might adversely affect our biological systems, even the reproductive systems through regulation of specific signaling pathways.

Regulation of egg quality and lipids metabolism by Zinc Oxide Nanoparticles.

This investigation was designed to explore the effects of Zinc Oxide Nanoparticles (ZnO NP) on egg quality and the mechanism of decreasing of yolk lipids. Different concentration of ZnO NP and ZnSO4 were used to treat hens for 24 weeks. The body weight and egg laying frequency were recorded and analyzed. Albumen height, Haugh unit, and yolk color score were analyzed by an Egg Multi Tester. Breaking strength was determined by an Egg Force Reader. Egg shell thickness was measured using an Egg Shell Thickness Gouge. Shell color was detected by a spectrophotometer. Egg shape index was measured by Egg Form Coefficient Measuring Instrument. Albumen and yolk protein was determined by the Kjeldahl method. Amino acids were determined by an amino acids analyzer. Trace elements Zn, Fe, Cu, and P (mg/kg wet mass) were determined in digested solutions using Inductively Coupled Plasma-Optical Emission Spectrometry. TC and TG were measured using commercial analytical kits. Yolk triglyceride, total cholesterol, pancreatic lipase, and phospholipids were determined by appropriate kits. ß-carotene was determined by spectrophotometry. Lipid metabolism was also investigated with liver, plasma, and ovary samples. ZnO NP did not change the body weight of hens during the treatment period. ZnO NP slowed down egg laying frequency at the beginning of egg laying period but not at later time. ZnO NP did not affect egg protein or water contents, slightly decreased egg physical parameters (12 to 30%) and trace elements (20 to 35%) after 24 weeks treatment. However, yolk lipids content were significantly decreased by ZnO NP (20 to 35%). The mechanism of Zinc oxide nanoparticles decreasing yolk lipids was that they decreased the synthesis of lipids and increased lipid digestion. These data suggested ZnO NP affected egg quality and specifically regulated lipids metabolism in hens through altering the function of hen's ovary and liver.

Cloning, expression and preliminary crystallographic analysis of the equine infectious anaemia virus (EIAV) gp45 ectodomain.

Like human immunodeficiency virus (HIV), equine infectious anaemia virus (EIAV) belongs to the lentivirus genus. The first successful lentiviral vaccine was developed for EIAV. Thus, EIAV may serve as a valuable model for HIV vaccine research. EIAV glycoprotein 45 (gp45) plays a similar role to gp41 in HIV by mediating virus-host membrane fusion. The gp45 ectodomain was constructed according to the structure of HIV gp41, with removal of the disulfide-bond loop region. The protein was expressed in Escherichia coli and crystallized following purification. However, most of the crystals grew as aggregates and could not be used for data collection. By extensively screening hundreds of crystals, a 2.7 Šresolution data set was collected from a single crystal. The crystal belonged to space group P6(3), with unit-cell parameters a = b = 46.84, c = 101.61 Å, α = ß = 90, γ = 120°. Molecular replacement was performed using the coordinates of various lengths of HIV gp41 as search models. A long bent helix was identified and a well defined electron-density map around the long helix was obtained. This primary model provided the starting point for further refinement.

[Establishment of stable cell line and expression and purification of HIV gp120 in Drosophila S2 cells].

Constructing eukaryotic expressing vector of pMT/Bip/V5-His A-HIV gp120 and transfecting S2 cells to establish stable gp120-expressing S2 cell line. The gp120 gene of HIV CRF07-BC epidemic in China was amplified by polymerase chain reaction from the recombinant vector PRSV-gp120 and confirmed by DNA sequence analysis. The DNA fragment of HIV gp120 was digested with the restriction endonucleases NcoI and XhoI, then inserted into eukaryotic expressing vector pMT/BiP/V5-His A. A selection vector containing the streptomyces griseochromogenes bsd gene conferring blasticidin resistance was cotransfected into drosophila S2 cells by Cellfectin II reagent. The stable cell line was established following repeated screening by blasticidin. HIV gp120 was purified by a Ni-NTA affinity column followed by molecular sieve chromatography. Recombinant protein was characterized by SDS-PAGE, Western blot and ELISA. The eukaryotic expressing vector pMT/BiP/V5-His A-HIV gp120 was constructed, stable expressing cell line was established, and protein was expressed and purified successfully. This result will contribute to functional study of gp120 and vaccine design against AIDS.

Theoretical mechanism study of UF6 hydrolysis in the gas phase (II).

In our previous work (J. Phys. Chem. A 2008, 112, 8877.), we found theoretical evidence indicating UF5OH is an intermediate produced in the first step of UF6 hydrolysis. In this work, we explored the probable reaction channels starting from UF5OH + UF6 and UF5OH + UF5OH systems using relativistic density functional theory calculations. Initially, the two uranium containing species associate to form complex UF6.UF5OH or dimer (UF5OH)2 through hydrogen bonding. The energy released is 12-16 kcal/mol, which may promote further reactions. After H2O or HF are eliminated from the complex or dimer, compounds containing U-O-U bond are produced. These compounds are potentially feasible to associate into larger clusters or solidify. Relative to the isolated initial species, the energies of the final products are -6 to -13 kcal/mol lower, indicating that the reactions may spontaneously proceed. The calculated IR spectra features can be used to indicate the formation and interaction type of the intermediates and products.

Theoretical mechanism study of UF6 hydrolysis in the gas phase.

The mechanism of the gas-phase reaction UF 6 + H 2O --> UOF 4 + 2HF is explored using relativistic density functional theory calculations. Initially, H 2O coordinates with UF 6 to form a 1:1 complex UF 6.H 2O. Over an activation energy barrier of about 19 kcal/mol, H 2O transfers a H atom to a nearby ligand F, resulting in UF 5OH + HF. The eliminated HF or another H 2O molecule may form a hydrogen bond with UF 5OH. Starting from UF 5OH, the second HF elimination results in UOF 4. If UF 5OH is in the isolated form, UF 5OH --> UOF 4 + HF takes place over a barrier of 24 kcal/mol. If UF 5OH is hydrogen-bonded with H 2O or HF, the conversion barrier is less than 10 kcal/mol. Once formed, the unstable UOF 4 tends to associate with additional ligands and hydrogen-bonding donors. The calculated binding energies indicate the significance of such interactions, which may have profound impact on further HF eliminating reactions. The IR spectra features can be used to indicate the formation and interaction type of the intermediates and products.

Influence of H2 on the gas-phase decomposition of formic acid: a theoretical study.

Gas-phase decomposition of formic acid results in final products CO + H2O and CO2 + H2. Experimentally, the CO/CO2 ratio tends to be large, in contradiction with mechanism studies, which show almost equal activation energies for dehydration and decarboxylation. In this work, the influence of H2 on the decomposition mechanism of HCOOH was explored using ab initio calculations at the CCSD(T)/6-311++G**//MP2/6-311++G** level. It was found that, in the presence of H2, the reaction channels leading to CO + H2O are more than those leading to CO2 + H2. With competitive energy, H2 addition to HCOOH can reduce the latter into HCHO, which then dissociates into CO + H2 catalyzed by H2O. Compared to trans-HCOOH, cis-HCOOH and cis-C(OH)2, conformers required for decarboxylation, are less populated due to interactions with H2.