Antimicrobial and Antiviral Nanofibers Halt Co-Infection Spread via Nuclease-Mimicry and Photocatalysis.

The escalating spread of drug-resistant bacteria and viruses is a grave concern for global health. Nucleic acids dominate the drug-resistance and transmission of pathogenic microbes. Here, imidazolium-type poly(ionic liquid)/porphyrin (PIL-P) based electrospun nanofibrous membrane and its cerium (IV) ion complex (PIL-P-Ce) are developed. The obtained PIL-P-Ce membrane exhibits high and stable efficiency in eradicating various microorganisms (bacteria, fungi, and viruses) and decomposing microbial antibiotic resistance genes and viral nucleic acids under light. The nuclease-mimetic and photocatalytic mechanisms of the PIL-P-Ce are elucidated. Co-infection wound models in mice with methicillin-resistant S. aureus and hepatitis B virus demonstrate that PIL-P-Ce integrate the triple effects of cationic polymer, photocatalysis, and nuclease-mimetic activities. As revealed by proteomic analysis, PIL-P-Ce shows minimal phototoxicity to normal tissues. Hence, PIL-P-Ce has potential as a "green" wound dressing to curb the spread of drug-resistant bacteria and viruses in clinical settings.

Mechanistic insights into diversified photoluminescence behaviours of BF2 complexes of N-benzoyl 2-aminobenzothiazoles.

Many BF2 complexes of heteroaromatics are well known for their dual-state emission (DSE) properties. However, AIE and ACQ effects have also been observed in certain cases. To date, no rational explanations have been proposed for these uncommon photoluminescence (PL) behaviours. The current research prepared four BF2 complexes of N-benzoyl 2-aminobenzothiazoles with diversified photoluminescence (PL) properties as model compounds and utilized quantum chemical calculation tools to address this issue. Theoretical calculations revealed that the electron-donating groups (EDGs) at the para-position of the exocyclic phenyl ring exert significant influence on their ground-state electronic structures and vertical excitation features. Potential energy curve (PEC) analysis showed that the exocyclic phenyl ring and NMe2 could not function as effective rotors due to elevated energy barriers. Only the NPh2 of BFBB-3 could spontaneously rotate ∼60° to induce the formation of an emissive twisted intramolecular charge transfer (TICT) state. The two-channel model involving both vibronic relaxation and S0/S1 surface crossing revealed that the drastic narrowing of the S1/S0 energy gap in the region approaching minimun energy conical intersection (MECI) led to the generation of a dark state in BFBB-1. The small energy barrier to access the dark-state region makes the resulting fast internal conversion a competitive channel for excited-state deactivation. In contrast, the presence of EDGs in BFBB-2 and 4 inhibits this pathway, thereby resulting in intense fluorescence emissions in solution. In addition, crystallographic analysis illustrated that the F atoms perpendicular to the polyheterocycle promoted a slipped face-to-face packing mode and enhanced intermolecular interactions. The efficiencies of their solid-state emissions are mainly affected by the degree of π-π overlaps.

Photoluminescent Properties and Mechanism of Novel Cyanine-Borondifluoride Curcuminoid Hybrids as Red-to-Near Infrared and Endoplasmic Reticulum-Targeting Dyes.

Synthesis-oriented design led us to the discovery of a series of novel cyanine-borondifluoride curcuminoid hybrids called Nanchang Red (NCR) dyes that overcome the intrinsic low synthetic yields of symmetrical cyanine-difluoroboronate (BF2 )-hybridized NIR dyes. The hybridization endows NCR dyes with high molar extinction coefficients, efficient red-to-NIR emission, and enlarged Stokes shifts. Quantum chemical calculations revealed that the asymmetrical layout of the three key electron-withdrawing and electron-donating fragments results in a special pattern of partial charge separation and inconsistent degrees of charge delocalization on their π-conjugated backbones. While the nature of the hemicyanine fragment exerts significant influence on the excitation modes of NCR dyes, the borondifluoride hemicurcuminoid fragment is the major contributor to the enlarged Stokes shifts. Cell imaging experiments illustrated that a subtle change in the N-heterocycle of the hemicyanine fragment has a remarkable effect on the subcellular localization of NCR dyes. Unlike other previously reported cyanine-BF2 hybridized dyes, which mainly target mitochondria, the benzothiazole and indole-based NCR dyes accumulate in both the endoplasmic reticulum (ER) and lipid droplets of HeLa cells, whereas the benzoxazole and quinoline-based NCR dyes stain the ER specifically.

Acceptance and commitment therapy reduces psychological distress in patients with cancer: a systematic review and meta-analysis of randomized controlled trials.

Objective: This study aimed to systematically review and meta-analyze the clinical efficacy of acceptance and commitment therapy (ACT) in patients with cancer and psychological distress. Methods: Randomized controlled trials (RCTs) from seven English electronic databases were systematically investigated from inception to 3 October 2023. A total of 16 RCTs from 6 countries with 711 participants were included in this study. Estimated pooled effect sizes (ESs) were calculated via inverse-variance random-effects or fixed-effects (I2 ≤ 50%) model and presented by standardized mean difference (SMD). Subgroup analyses were performed to reduce confounding factors and heterogeneity, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to evaluate the quality of the pooled ESs. Results: The pooled ESs revealed that statistically significant improvements in anxiety [postintervention SMD = -0.41 (95% confidence interval (CI), -0.71, -0.11); p = 0.008; I2 = 65%; follow-up SMD = -0.37 (95% CI, -0.66, -0.08); p = 0.01; I2 = 29%], depression [postintervention SMD = -0.45 (95% CI, -0.63, -0.27); p < 0.001; I2 = 49%; follow-up SMD = -0.52 (95% CI, -0.77, -0.28); p < 0.001; I2 = 0%], and psychological flexibility [postintervention SMD = -0.81 (95% CI, -1.50, -0.11); p = 0.02; I2 = 84%; follow-up SMD = -0.71 (95% CI, -1.12, -0.31); p = 0.0006; I2 = 38%] in ACT-treated participants were observed compared to patients treated with control conditions. However, other outcomes, such as physical symptom alleviation, were not significantly associated. Conclusion: The findings of this systematic review and meta-analysis suggest that ACT is associated with improvements in anxiety, depression, and psychological flexibility in patients with cancer. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022320515.

Antimicrobial poly(ionic liquid)-induced bacterial nanotube formation and drug-resistance spread.

Bacterial nanotubes are tubular membranous structures bulging from the cell surface that can connect neighboring bacteria for the exchange of intercellular substances. However, little is known about the formation and function of bacterial nanotubes under the stress of antimicrobial materials. Herein, an imidazolium-type cationic poly(ionic liquid) (PIL) and corresponding PIL membranes with antimicrobial properties were synthesized. The effects of these cationic polymers on the formation of bacterial nanotubes between Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) or Vibrio fischeri (V. fischeri), followed by intraspecies and interspecies exchange of antibiotic resistance genes (ARGs) were investigated. The results showed that bacteria tend to produce more nanotubes accompanied by drug-resistance trade, which can even make the ARGs of pathogens spread to the environmental microbes of V. fischeri. Given the unique antimicrobial sustainability toward bacteria after they acquire ARGs via bacterial nanotubes, antimicrobial PILs demonstrate bright prospects in the battle against resistant bacteria.

Structural dynamics of the cooperative binding of small inhibitors in human cytochrome P450 2C9.

Some non-steroidal anti-inflammatory drugs (NSAIDs) exhibit atypical kinetic behavior when binding together with dapsone in CYP2C9. However, few studies about the detailed multi-drug binding dynamics in CYP2C9 have been reported. Here, molecular docking and molecular dynamics (MD) simulations are performed to explore the cooperative binding of dapsone and three NSAIDs in CYP2C9. The docking results show that dapsone bind to not only the distal primay bind site but also the active site above the heme group. Flurbiprofen/naproxen and piroxicam are located in the active site and the primary binding site of CYP2C9, respectively. It is noted that some key hydrogen bond (H-bond) and hydrophobic interactions mediate the conformational changes of substrates. Moreover, the calculated binding affinity is in line with experimental results. Further, the residue energy decomposition reveals that van der Waals energies of backbone/side-chain atoms dominate the substrate-binding and they can be ascribed to π···π, C-H···π, C-H⋯H-C interactions.

Acridine-Based Covalent Organic Framework Photosensitizer with Broad-Spectrum Light Absorption for Antibacterial Photocatalytic Therapy.

Antibiotic resistance is considered as one of the serious public health issues. Antibacterial photocatalytic therapy, a clinically proven antibacterial therapy, is gaining increasing attention in recent years owing to its high efficacy. Here, an acridine-based covalent organic framework (COF) photosensitizer, named TPDA, with multiple active sites is synthesized via Schiff base condensation between 2,4,6-triformylphloroglucinol (TFP) and 3,6-diaminoacridine (DAA). Owing to the increased conjugation effect of the COF skeleton and outstanding light harvesting ability of DAA, TPDA exhibits a narrow optical band gap (1.6 eV), enhancing light energy transformation and conferring a wide optical absorption spectrum (intensity arbitrary unit > 0.8) ranging from the UV to near-infrared region. Moreover, TPDA shows high antibacterial activities against both gram-negative and gram-positive bacteria within a short time (10 min) of light irradiation and is found to efficiently protect fish from skin infections. Molecular dynamics simulation data show that the introduction of DAA and TFP facilitates the interaction between TPDA and bacteria and is conducive to reactive oxygen species migration, which further improves the antimicrobial performance. These findings indicate the potential of TPDA as a novel photosensitive material for photodynamic therapy.

Robust and High-Temperature-Resistant Nanofiber Membrane Separators for Li-Metal, Li-Sulfur, and Aqueous Li-Ion Batteries.

Mechanically strong separators with good electrolyte wettability and low-shrinkage properties are desirable for highly efficient and safe lithium batteries. In this study, multifunctional nanofiber membranes are fabricated by electrospinning a homogeneous solution containing amphiphilic poly(ethylene glycol)diacrylate-grafted siloxane and polyacrylonitrile. After the chemical cross-linking of siloxane, the prepared nanofiber membranes are found to exhibit good mechanical properties, high thermostability, and superior electrolyte-philicity with aqueous and nonaqueous electrolytes. Li-metal cells with the fabricated membrane separator exhibit high cycling stability (Coulombic efficiency of 99.8% after 1000 cycles). Moreover, improved cycling stability of Li-sulfur batteries can be achieved using these membrane separators. These membrane separators can be further used in flexible aqueous lithium-ion batteries and exhibit steady electrochemistry performance. This work opens up a potential route for designing multifunctional universal separators for rechargeable batteries.

Amino-1H-tetrazole-regulated high-density nitrogen-doped hollow carbon nanospheres for long-life Zn-air batteries.

High-density nitrogen-doped porous carbon catalysts have been regarded as promising alternatives to precious metals in proton-exchange membrane fuel cells (PEMFC) and metal-air batteries based on the oxygen reduction reaction (ORR). We herein synthesized high-density pyridinic and graphitic N-doped hollow carbon nanospheres (G&P N-HCS) using a high-yield amino-1H-tetrazole (ATTZ) via a self-sacrificial-template method. The synthesized G&P N-HCS shows a high N content (15.2 at%), in which pyridinic (Pr) and graphitic (Gr) N are highly reactive for the ORR catalysis. We found that the half-wave potential and limiting current density of G&P N-HCS are comparable to the state-of-the-art Pt/C, whereas its cyclic durability is much superior to that of Pt/C. Experimental results indicate that an optimal ratio (1 : 1) between Gr N and Pr N in G&P N-HCS exhibits the highest ORR performances, rather than Gr N-dominated N-HCS or Pr N-dominated N-HCS. Notably, N-HCS containing only Gr N and Pr N has poor catalytic performance for ORR in alkaline electrolytes. Density functional theory (DFT) simulations untangle the catalytic nature of Pr and Gr N and decipher the relations between the N type(s) and total N content required for the ORR catalysis. This study provides a new way to design efficient N-doped porous carbon-enriched active sites, and solves the cathode catalyst in the commercialization of PEMFC and metal-air batteries.

Integrated Endotoxin Adsorption and Antibacterial Properties of Cationic Polyurethane Foams for Wound Healing.

Gram-negative bacteria, containing toxic proinflammatory and pyrogenic substances [endotoxin or lipopolysaccharide (LPS)], can lead to infection and associated serious diseases, such as sepsis and septic shock. Development of antimicrobial materials with intrinsically endotoxin adsorption activity can prevent the release of bacterial toxic components while killing bacteria. Herein, a series of imidazolium-type polyurethane (PU) foams with antimicrobial properties were synthesized. The content effects of cationic moieties on the antimicrobial activities against Gram-negative Escherichia coli and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus as well as the endotoxin adsorption property were investigated. The obtained PU foams show slightly higher efficiency against two Gram-negative strains than for Gram-positive one and high absorbability of LPS. A wound healing test using P. aeruginosa and its isolated LPS-treated mice as the models further demonstrated that imidazolium-type PU foams combine both antibacterial and endotoxin adsorption properties and may have a potential application as an antimicrobial wound dressing in a clinical setting.

Polyanionic Antimicrobial Membranes: An Experimental and Theoretical Study.

Polycationic polymers have been widely used as antimicrobial materials because of their broad spectrum activity and potential use as new antibiotics. Herein, we report the synthesis of polyanionic antimicrobial membranes by in situ photo-cross-linking of a sulfate based anionic monomer, followed by cation-exchange with organic (quaternary ammonium or imidazolium) or metal (Ag+, Cu2+, Fe3+, Zn2+, Na+, K+) cations. The resultant polyanionic membranes show high and broad spectrum antibacterial activities against both bacteria (Escherichia coli, Staphylococcus aureus) and fungi (Candida albicans ). In addition, the polyanionic antimicrobial membranes efficiently inhibited the formation of biofilms by SC5314 and its crk1 gene deleted (Δcrk1) C. albicans strains. Furthermore, the synthesized polyanionic membranes exhibit good blood compatibility, low cytotoxicity and long-term antibacterial stability, demonstrating safe antimicrobial materials in the application of healthcare.

Quantum chemical study on the stability of honeybee queen pheromone against atmospheric factors.

The managed honeybee, Apis mellifera, has been experienced a puzzling event, termed as colony collapse disorder (CCD), in which worker bees abruptly disappear from their hives. Potential factors include parasites, pesticides, malnutrition, and environmental stresses. However, so far, no definitive relationship has been established between specific causal factors and CCD events. Here we theoretically test whether atmospheric environment could disturb the chemical communication between the queen and their workers in a colony. A quantum chemistry method has been used to investigate for the stability of the component of A. mellifera queen mandibular pheromone (QMP), (E)-9-keto-2-decenoic acid (9-ODA), against atmospheric water and free radicals. The results show that 9-ODA is less likely to react with water due to the high barrier heights (~36.5 kcal · mol(-1)) and very low reaction rates. However, it can easily react with triplet oxygen and hydroxyl radicals because of low or negative energy barriers. Thus, the atmospheric free radicals may disturb the chemical communication between the queen and their daughters in a colony. Our pilot study provides new insight for the cause of CCD, which has been reported throughout the world.

3-D modeling and molecular dynamics simulation of interleukin-22 from the So-iny mullet, Liza haematocheila

Background: Interleukin-22 (IL-22) plays an important role in the regulation of immune responses. However, little is known about its function or structure in fish. Results: The IL-22 gene was first cloned from So-iny mullet (Liza haematocheila), one of commercially important fish species in China. Then, 3-D structure model of the mullet IL-22 was constructed by comparative modeling method using human IL-22 (1M4R) as template, and a 5 ns molecular dynamics (MD) was studied. The open reading frame (ORF) of mullet IL-22 cDNA was 555 bp, encoding 184 amino acids. The mullet IL-22 shared higher identities with the other fish IL-22 homologs and possessed a conserved IL-10 signature motif at its C-terminal. The mullet IL-22 model possessed six conserved helix structure. PROCHECK, SAVES and Molprobity server analysis confirmed that this model threaded well with human IL-22. Strikingly, analysis with CastP, cons-PPISP server suggested that the cysteines in mullet IL-22 might not be involved in the forming of disulfide bond for structural stabilization, but related to protein-protein interactions. Conclusions: The structure of IL-22 in So-iny mullet (Liza haematocheila) was constructed using comparative modeling method which provide more information for studying the function of fish IL-22.

Simultaneous determination of morinidazole, its N-oxide, sulfate, and diastereoisomeric N(+)-glucuronides in human plasma by liquid chromatography-tandem mass spectrometry.

Morinidazole is a new third-generation 5-nitroimidazole antimicrobial drug. To investigate the pharmacokinetic profiles of morinidazole and its major metabolites in humans, a liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous determination of morinidazole, its N-oxide metabolite (M4-1), a sulfate conjugate (M7), and two diastereoisomeric N(+)-glucuronides (M8-1 and M8-2) in human plasma. A simple acetonitrile-induced protein precipitation was employed to extract five analytes and internal standard metronidazole from 50µL human plasma. To avoid the interference from the in-source dissociation of the sulfate and achieve the baseline-separation of diastereoisomeric N(+)-glucuronides, all the analytes were separated from each other with the mobile phase consisting of 10mM ammonium formate and acetonitrile using gradient elution on a Hydro-RP C(18) column (50mm×2mm, 4µm) with a total run time of 5min. The API 4000 triple quadrupole mass spectrometer was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. The developed method was linear in the concentration ranges of 10.0-12,000ng/mL for morinidazole, 1.00-200ng/mL for M4-1, 2.50-500ng/mL for M7, 3.00-600ng/mL for M8-1, and 10.0-3000ng/mL for M8-2. The intra- and inter-day precisions for each analyte met the accepted value. Results of the stability of morinidazole and its metabolites in human plasma were also presented. The method was successfully applied to the clinical pharmacokinetic studies of morinidazole injection in healthy subjects, patients with moderate hepatic insufficiency, and patients with severe renal insufficiency, respectively.

Exploration of the binding of curcumin analogues to human P450 2C9 based on docking and molecular dynamics simulation.

Molecular docking and molecular dynamics (MD) simulations are used to investigate the interactions of curcumin analogues (CAs) with human cytochrome P450 2 C9 (CYP2C9 or 2 C9) and the conformations of their binding sites. In order to examine conformations of CAs/2 C9 and interaction characteristics of their binding sites, RMSDs, RMSFs, and B-factors are computed, and electrostatic and hydrophobic interactions between CAs and 2 C9 are analyzed and discussed. Results demonstrate that the most CAs studied lie 4~15 Å above the heme of CYP2C9. The presence of CAs makes some residues in bound CYP2C9s become more flexible. In the binding sites of A0/2 C9 and C0/2 C9, the formation of H-bond networks (or CA-water-residue bridges) enhances the interactions between CAs and 2 C9. The stronger inhibitory effects of A0, B0, and C0 on 2 C9 can be ascribed to stronger electrostatic and hydrophobic interactions in the binding sites of CAs/2 C9.

Exploration of the binding of proton pump inhibitors to human P450 2C9 based on docking and molecular dynamics simulation.

Human P450 protein CYP2C9 is one of the major drug-metabolizing isomers, contributing to the oxidation of 16% of the drugs currently in clinical use. To examine the interaction mechanisms between CYP2C9 and proton pump inhibitions (PPIs), we used molecular docking and molecular dynamics (MD) simulation methods to investigate the conformations and interactions around the binding sites of PPIs/CYPP2C9. Results from molecular docking and MD simulations demonstrate that nine PPIs adopt two different conformations (extended and U-bend structures) at the binding sites and position themselves far above the heme of 2C9. The presence of PPIs changes the secondary structures and residue flexibilities of 2C9. Interestingly, at the binding sites of all PPI-CYP2C9 complexes except for Lan/CYP2C9, there are hydrogen-bonding networks made of PPIs, water molecules, and some residues of 2C9. Moreover, there are strong hydrophobic interactions at all binding sites for PPIs/2C9, which indicate that electrostatic interactions and hydrophobic interactions appear to be important for stabilizing the binding sites of most PPIs/2C9. However, in the case of Lan/2C9, the hydrophobic interactions are more important than the electrostatic interactions for stabilizing the binding site. In addition, an interesting conformational conversion from extended to U-bend structures was observed for pantoprazole, which is attributed to an H-bond interaction in the binding pocket, an internal π-π stacking interaction, and an internal electrostatic interaction of pantoprazole.

Exploration of the binding of benzimidazole-biphenyl derivatives to hemoglobin using docking and molecular dynamics simulation.

In this study, the binding of hemoglobin (Hb) with three benzimidazole-biphenyl derivatives (telmisartan (TST), candesartan (CST), and DB921) is investigated by molecular docking, molecular dynamics (MD) simulation, and binding free energy calculation. Results demonstrate that the three drugs locate in the cavities formed by α1, α2, and ß2 subunits. The average gyration radii are estimated and consistent with available experimental results. The binding free energies suggest that the binding site of CST/Hb is more stable than those of TST/Hb and DB921/Hb. The energy decomposition analysis is performed and reveals that the electrostatic interactions play an important role in the stabilization of the binding site of CST/Hb or DB921/Hb while the van der Waals interactions contribute largely to stabilization of the binding site of TST/Hb. The key residues stabilizing the binding sites of TST/Hb, CST/Hb, and DB921/Hb are identified based on the residue decomposition analysis. The probability densities of salt bridge distances demonstrate that there still exist the four salt bridges between α1 and α2 subunits of Hb in presence of these drugs.

Search for structures, potential energy surfaces, and stabilities of planar BnP(n = 1 ∼ 7).

We have systematically explored and investigated the geometrical structures, stability, growth pattern, bonding character, and potential energy surface (PES) of the possible isomers of each cluster for planar B(n)P (n = 1 ∼ 7) at the CCSD(T)/6-311+;G(d)//B3LYP/6-311+G(d) level. A large number of planar structures for the possible isomers of B(n)P (n = 1 ∼ 7) and transition states are located. Isomers 1a ∼ 7a of B(n)P are the lowest-energy structures and 2a, 4a, as well as 6a are more stable than their neighbors. For the lowest-energy structures (1a ∼ 7a) of B(n)P, P atom lies at the apex and tends to form two B-P bonds with boron atoms. They exhibit planar zigzag growth feature or approximately spherical-like growth pattern. Results from molecular orbital analysis demonstrate that the formation of the delocalized π MOs and the σ-radial and σ-tangential MOs plays a critical role in stabilizing the structures of lowest-energy isomers (2a ∼ 7a) of B(n)P. Importantly, isomers 3a, 3c, 3d, 4a, 4b, 5b, and 5c of B(n)P are stable both thermodynamically and kinetically at the CCSD(T)/6-311+G(d)// B3LYP/6-311+G(d) level and detectable in laboratory, which is valuable for further experimental studies of B(n)P.

Exploration of the mechanism for LPFFD inhibiting the formation of beta-sheet conformation of A beta(1-42) in water.

The main component of senile plaques found in AD brain is amyloid beta-peptide (A beta), and the neurotoxicity and aggregation of A beta are associated with the formation of beta-sheet structure. Experimentally, beta sheet breaker (BSB) peptide fragment Leu-Pro-Phe-Phe-Asp (LPFFD) can combine with A beta, which can inhibit the aggregation of A beta. In order to explore why LPFFD can inhibit the formation of beta-sheet conformation of A beta at atomic level, first, molecular docking is performed to obtain the binding sites of LPFFD on the A beta(1-42) (LPFFD/A beta(1-42)), which is taken as the initial conformation for MD simulations. Then, MD simulations on LPFFD/A beta(1-42) in water are carried out. The results demonstrate that LPFFD can inhibit the conformational transition from alpha-helix to beta-sheet structure for the C-terminus of A beta(1-42), which may be attributed to the hydrophobicity decreasing of C-terminus residues of A beta(1-42) and formation probability decreasing of the salt bridge Asp23-Lys28 in the presence of LPFFD.

Exploration of structure, potential energy surface, and stability of planar C3B3.

The geometrical structures, potential energy surface, stability, and bonding character of low-energy isomers of planar C(3)B(3) were systematically explored and investigated at the B3LYP/6-311+G(d)// CCSD(T)/6-311+G(d) level for the first time. A large number of planar structures for low-energy isomers of C(3)B(3) are located and reported. In particular, isomers 1 (C(s),(2)A') and 2 (C(s),(2)A'), with a belt-like structure corresponding to the lowest-energy structures of planar C(3)B(3), are revealed. Based on molecular orbital (MO) and natural bond orbital (NBO) analyses, delocalized sigma MOs, multi-centered sigma MOs, and delocalized pi MOs play an important role in stabilizing the structures of low-energy isomers of C(3)B(3). It is interesting to note from isomerization analysis that the interconversion of isomers 2 and 7 can be realized through two isomerization channels. The results demonstrate that isomers 1, 2, 3, 4, 7, 9, 12, 17, 19, and 20 of C(3)B(3) are stable both thermodynamically and kinetically at the B3LYP/ 6-311+G(d)//CCSD(T)/ 6-311+G(d) level, and that they are observable in the laboratory, which is helpful for future experimental studies of C(3)B(3).