Open-field exploration immediately before the retention test impairs retrieval and spaced fear extinction of contextual fear memory.

According to the behavioral tagging theory, various stages of fear memory, such as contextual fear conditioning, memory retrieval, and fear extinction, can be facilitated by the exploration of a novel open field (OF). A critical time window of efficacy exists for this process. Novel exploration closely adjacent to weak learning may interfere with the setting of the learning tag, leading to a negative effect. In this mouse study, we consistently showed that exposure to a novel or familiar OF immediately prior to the retention test impaired the retrieval of long-term contextual fear memory. However, OF exposure had no effect on the retrieval of recent or remote cued fear memory or short-term contextual fear memory or the reconsolidation of contextual fear memory. In addition, OF exposure impaired spaced but not massed extinction of contextual fear memory. These results suggest that interfering stimulus may result in the transient forgetting of fear memory; however, temporary loss of fear may lead to retention failure of fear extinction. The results of this study are an important complement to the behavioral tagging theory and may provide new guidance for the treatment of post-traumatic stress disorder.

A highly selective PI3Kδ inhibitor BGB-10188 shows superior preclinical anti-tumor activities and decreased on-target side effects on colon.

PI3Kδ is a key signal transduction molecule in normal and malignant B cells, as well as in T-regulatory cells, making it a promising target for treatment of hematologic malignancies through both direct killing and anti-tumor immunity regulation. BGB-10188 is a highly selective inhibitor of PI3Kδ, showing more than 3000 folds selectivity over other PI3K isoforms and no significant inhibition across tested kinases. BGB-10188 potently inhibited PI3Kδ with IC50s ranging from 1.7-16 nM through various in vitro assays and showed a long-lasting and strong target inhibition in mouse B cells in vivo. BGB-10188 showed significant antitumor effects in human B cell lymphoma xenograft models as single agent or in combination with the BTK inhibitor zanubrutinib. BGB-10188 showed significant Treg inhibition in blood but not in colon, along with less drug accumulation in colon compared with idelalisib, which is an approved PI3Kdelta inhibitor with high incidence of gastrointestinal side effects in clinic. In summary, BGB-10188 is a novel PI3Kδ inhibitor with high selectivity, potency and improved safety profile shown in preclinical studies, which is showing the potential as a best-in-class PI3Kδ inhibitor.

Probing the Structures and Lanthanum-Lanthanum Bonding in La2Bn- (n = 4-6) Clusters.

We report an investigation on the structures and chemical bonding in a series of di-lanthanum boron clusters, La2Bn- (n = 4-6), using photoelectron spectroscopy and theoretical calculations. Well-resolved photoelectron spectra are obtained and used to verify the global minima of the lanthanide boron clusters. The structures of La2B4- and La2B5- are found to consist of open B4 and B5 rings, respectively, around the La2 dimer equatorially. Theoretical evidence of La-La σ bonding is obtained in La2B4-, whereas the bonding in La2B5- is similar to that of an incomplete inverse sandwich without real La-La bonding. The global minimum of La2B6- is completely different, where one of the La atoms can be viewed as substituting a B atom of the B7 cluster due to the high electronic stability of the B73- borozene. The resulting lanthaborozene [LaB6]3- forms a half-sandwich structure with the second La atom, with evidence of La-La σ bonding. Lanthanide-lanthanide bonds are relatively rare in chemistry. The current work suggests that binary lanthanide boron clusters provide interesting systems to study lanthanide-lanthanide bonding.

Acute systemic macrophage depletion in osteoarthritic mice alleviates pain-related behaviors and does not affect joint damage.

Background: Osteoarthritis (OA) is a painful degenerative joint disease and a leading source of years lived with disability globally due to inadequate treatment options. Neuroimmune interactions reportedly contribute to OA pain pathogenesis. Notably, in rodents, macrophages in the DRG are associated with onset of persistent OA pain. Our objective was to determine the effects of acute systemic macrophage depletion on pain-related behaviors and joint damage using surgical mouse models in both sexes. Methods: We depleted CSF1R+ macrophages by treating male macrophage Fas-induced apoptosis (MaFIA) transgenic mice 8- or 16-weeks post destabilization of the medial meniscus (DMM) with AP20187 or vehicle control (10 mg/kg i.p., 1x/day for 5 days), or treating female MaFIA mice 12 weeks post partial meniscectomy (PMX) with AP20187 or vehicle control. We measured pain-related behaviors 1-3 days before and after depletion, and, 3-4 days after the last injection we examined joint histopathology and performed flow cytometry of the dorsal root ganglia (DRGs). In a separate cohort of male 8-week DMM mice or age-matched naïve vehicle controls, we conducted DRG bulk RNA-sequencing analyses after the 5-day vehicle or AP20187 treatment. Results: Eight- and 16-weeks post DMM in male mice, AP20187-induced macrophage depletion resulted in attenuated mechanical allodynia and knee hyperalgesia. Female mice showed alleviation of mechanical allodynia, knee hyperalgesia, and weight bearing deficits after macrophage depletion at 12 weeks post PMX. Macrophage depletion did not affect the degree of cartilage degeneration, osteophyte width, or synovitis in either sex. Flow cytometry of the DRG revealed that macrophages and neutrophils were reduced after AP20187 treatment. In addition, in the DRG, only MHCII+ M1-like macrophages were significantly decreased, while CD163+MHCII- M2-like macrophages were not affected in both sexes. DRG bulk RNA-seq revealed that Cxcl10 and Il1b were upregulated with DMM surgery compared to naïve mice, and downregulated in DMM after acute macrophage depletion. Conclusions: Acute systemic macrophage depletion reduced the levels of pro-inflammatory macrophages in the DRG and alleviated pain-related behaviors in established surgically induced OA in mice of both sexes, without affecting joint damage. Overall, these studies provide insight into immune cell regulation in the DRG during OA.

Borozenes: Benzene-Like Planar Aromatic Boron Clusters.

ConspectusWith three valence electrons and four valence orbitals, boron (2s22p1) is an electron-deficient element, resulting in interesting chemical bonding and structures in both borane molecules and bulk boron materials. The electron deficiency leads to electron sharing and delocalization in borane compounds and bulk boron allotropes, characterized by polyhedral cages, in particular, the ubiquitous B12 icosahedral cage. During the past two decades, the structures and bonding of size-selected boron clusters have been elucidated via combined photoelectron spectroscopy and theoretical investigations. Unlike bulk boron materials, finite boron clusters have been found to possess 2D structures consisting of B3 triangles, dotted with tetragonal, pentagonal, or hexagonal holes. The discovery of the planar B36 cluster with a central hexagonal hole provided the first experimental evidence for the viability of 2D boron nanostructures (borophene), which have been synthesized on inert substrates. The B7-, B8-, and B9- clusters were among the first few boron clusters to be investigated by joint photoelectron spectroscopy and theoretical calculations, and they were all found to possess 2D structures with a central B atom inside a Bn ring. Recently, the B73- (C6v), B82- (D7h), and B9- (D8h) series of closed-shell species were shown to possess similar π bonding akin to that in the C5H5-, C6H6, and C7H7+ series, respectively, and the name "borozene" was coined to highlight their analogy to the classical aromatic hydrocarbon molecules.Among the borozenes, the D7h B82- species is unique for its high stability originating from both its double aromaticity and the fact that the B7 ring has the perfect size to host a central B atom. The B82- borozene has been realized experimentally in a variety of MB8 and M2B8 complexes. In particular, the B82- borozene has been observed to stabilize the rare valence-I oxidation state of lanthanides in LnB8- complexes, as well as a Cu2+ species in Cu2B8-. The B6 ring in B73- is too small to host a B atom, resulting in a slight out-of-plane distortion. Interestingly, the bowl-shaped B7 borozene is perfect for coordination to a metal atom, leading to the observation of a series of highly stable MB7 borozene complexes. On the other hand, the B8 ring is slightly too large to host the central B atom, such that a low-lying and low-symmetry isomer also exists for B9-. Even though most 2D boron clusters are aromatic, the B73-, B82-, and B9- borozenes are special because of their high symmetries and their analogy to the series of C5H5-, C6H6, and C7H7+ prototypical aromatic compounds. This Account discusses recent experimental and theoretical advances on the investigations of various borozene complexes. It is expected that many new borozene compounds can be designed and may be eventually synthesized.

Chemoenzymatic Synthesis of Sulfated N-Glycans Recognized by Siglecs and Other Glycan-Binding Proteins.

Sulfated N-glycans are present in many glycoproteins, which are implicated in playing important roles in biological recognition processes. Here, we report the systematic chemoenzymatic synthesis of a library of sulfated and sialylated biantennary N-glycans and assess their binding to Siglecs and glycan-specific antibodies that recognize them as glycan ligands. The combined use of three human sulfotransferases, GlcNAc-6-O-sulfotransferase (CHST2), Gal-3-O-sulfotransferase (Gal3ST1), and keratan sulfate Gal-6-O-sulfotransferase (CHST1), resulted in asymmetric and symmetric branch-selective sulfation of the GlcNAc and/or Gal moieties of N-glycans. The extension of the sugar chain using α-2,3- and α-2,6-sialyltransferases afforded the sulfated and sialylated N-glycans. These synthetic glycans with different patterns of sulfation and sialylation were evaluated for binding to selected Siglecs and sulfoglycan-specific antibodies using glycan microarrays. The results confirm previously documented glycan-recognizing properties and further reveal novel specificities for these glycan-binding proteins, demonstrating the utility of the library for assessing the specificity of glycan-binding proteins recognizing sulfated and sialylated glycans.

A Comprehensive Research Review of Herbal Textual Research, Phytochemistry, Pharmacology, Traditional Uses, Clinical Application, Safety Evaluation, and Quality Control of Trollius chinensis Bunge.

Trollius chinensis Bunge (TCB) is a perennial plant of the Ranunculaceae family with medicinal and edible values. It is widely distributed and commonly used in various regions, including Asia, Europe, and North America. The main chemical components of TCB include alkaloids, flavonoids, phenolic acids, and volatile oil compounds. TCB is renowned for its anti-inflammatory, heat-clearing, detoxifying, and eyesight-improving properties. Its dried flowers are commonly used as a traditional Chinese medicine indicated for the treatment of upper respiratory tract infections, chronic tonsillitis, pharyngitis, influenza, and bronchitis. Modern pharmacology has demonstrated the anti-cancer, anti-inflammatory, antihypertensive, and antioxidant effects of TCB. This study presents a comprehensive overview of various aspects of TCB, including herbal textual research, botany, phytochemistry, pharmacology, traditional uses, clinical application, and quality control, aiming to provide new ideas on the scientific application of TCB as well as the integration of modern research with traditional medicinal uses.

Ultrafast evanescently coupled waveguide MUTC-PDs with high responsivity.

Novel evanescently coupled waveguide modified uni-traveling carrier photodiodes (MUTC-PDs) employing a thick multi-layer coupling waveguide are reported. To improve the optical-to-electrical (O/E) conversion efficiency, a thick multi-layer coupling waveguide with a gradually increased refractive index from the bottom layer to the absorption layer is utilized. The refractive index profile facilitates the upward transmission of incident light into the absorption region, thereby enhancing the evanescent coupling efficiency. Meanwhile, the coupling waveguide, with a total thickness of 1.75 µm, expands the mode field diameter, thereby reducing the input coupling loss. Additionally, the top layer of the coupling waveguide also serves as the drift layer. This configuration facilitates efficient light absorption within a short PD length, thus ensuring ultrawide bandwidth and high O/E conversion efficiency simultaneously. Without an additional spot size coupler or anti-reflection coating, the measured responsivity is as high as 0.38 A/W for the PD with an active area of 5 × 6 µm2. Meanwhile, an ultrawide 3-dB bandwidth of 153 GHz has been demonstrated.

Effect of salt-alkali stress on seed germination of the halophyte Halostachys caspica.

The increasing global phenomenon of soil salinization has prompted heightened interest in the physiological ecology of plant salt and alkali tolerance. Halostachys caspica belonging to Amaranthaceae, an exceptionally salt-tolerant halophyte, is widely distributed in the arid and saline-alkali regions of Xinjiang, in Northwest China. Soil salinization and alkalinization frequently co-occur in nature, but very few studies focus on the interactive effects of various salt and alkali stress on plants. In this study, the impacts on the H. caspica seed germination, germination recovery and seedling growth were investigated under the salt and alkali stress. The results showed that the seed germination percentage was not significantly reduced at low salinity at pH 5.30-9.60, but decreased with elevated salt concentration and pH. Immediately after, salt was removed, ungerminated seeds under high salt concentration treatment exhibited a higher recovery germination percentage, indicating seed germination of H. caspica was inhibited under the condition of high salt-alkali stress. Stepwise regression analysis indicated that, at the same salt concentrations, alkaline salts exerted a more severe inhibition on seed germination, compared to neutral salts. The detrimental effects of salinity or high pH alone were less serious than their combination. Salt concentration, pH value, and their interactions had inhibitory effects on seed germination, with salinity being the decisive factor, while pH played a secondary role in salt-alkali mixed stress.

Lipopolysaccharide released from gut activates pyroptosis of macrophages via Caspase 11-Gasdermin D pathway in systemic lupus erythematosus.

Noncanonical pyroptosis is triggered by Caspase 4/5/11, which cleaves Gasdermin D (GSDMD), leading to cell lysis. While GSDMD has been studied previously in systemic lupus erythematosus (SLE), the role of pyroptosis in SLE pathogenesis remains unclear and contentious, with limited understanding of Caspase 11-mediated pyroptosis in this condition. In this study, we explored the level of Caspase 11-mediated pyroptosis in SLE, identifying both the upstream pathways and the interaction between pyroptosis and adaptive immune responses. We observed increased Caspase 5/11 and GSDMD-dependent pyroptosis in the macrophages/monocytes of both lupus patients and mice. We identified serum lipopolysaccharide (LPS), released from the gut due to a compromised gut barrier, as the signal that triggers Caspase 11 activation in MRL/lpr mice. We further discovered that pyroptotic macrophages promote the differentiation of mature B cells independently of T cells. Additionally, inhibiting Caspase 11 and preventing LPS leakage proved effective in improving lupus symptoms in MRL/lpr mice. These findings suggest that elevated serum LPS, resulting from a damaged gut barrier, induces Caspase 11/GSDMD-mediated pyroptosis, which in turn promotes B cell differentiation and enhances autoimmune responses in SLE. Thus, targeting Caspase 11 could be a viable therapeutic strategy for SLE.

Microglial activation in the medial prefrontal cortex after remote fear recall participates in the regulation of auditory fear extinction.

Excessive or inappropriate fear responses can lead to anxiety-related disorders, such as post-traumatic stress disorder (PTSD). Studies have shown that microglial activation occurs after fear conditioning and that microglial inhibition impacts fear memory. However, the role of microglia in fear memory recall remains unclear. In this study, we investigated the activated profiles of microglia after the recall of remote-cued fear memory and the role of activated microglia in the extinction of remote-cued fear in adult male C57BL/6 mice. The results revealed that the expression of the microglia marker Iba1 increased in the medial prefrontal cortex (mPFC) at 10 min and 1 h following remote-cued fear recall, which was accompanied by amoeboid morphology. Inhibiting microglial activation through PLX3397 treatment before remote fear recall did not affect recall, reconsolidation, or regular extinction but facilitated recall-extinction and mitigated spontaneous recovery. Moreover, our results demonstrated reduced co-expression of Iba1 and postsynaptic density protein 95 (PSD95) in the mPFC, along with decreases in the p-PI3K/PI3K ratio, p-Akt/Akt ratio, and KLF4 expression after PLX3397 treatment. Our results suggest that microglial activation after remote fear recall impedes fear extinction through the pruning of synapses in the mPFC, accompanied by alterations in the expression of the PI3K/AKT/KLF4 pathway. This finding can help elucidate the mechanism involved in remote fear extinction, contributing to the theoretical foundation for the intervention and treatment of PTSD.

Sessile serrated lesion prevalence and factors associated with their detection: a post-hoc analysis of a multinational randomized controlled trial from Asia.

BACKGROUND: Sessile serrated lesions (SSLs) are associated with an increased risk of colorectal cancer. Data on the prevalence of SSLs in Asia are limited. We performed this study to estimate the prevalence of SSLs in Asia and to explore endoscopic factors that are associated with SSL detection. METHODS: This is a post-hoc analysis of a multicenter randomized controlled trial from four Asian countries/regions that compared adenoma detection rates using linked-color imaging (LCI) and white-light imaging. Colonoscopies were performed in an average-risk population for screening, diagnostic examination, or polyp surveillance. Patients with SSLs were compared against those without SSLs to evaluate for possible predictors of SSL detection using Firth's logistic regression. RESULTS: 2898 participants (mean age 64.5 years) were included in the analysis. The estimated prevalence of SSLs was 4.0% (95%CI 3.4%-4.8%), with no sex or age group differences. On multivariable analysis, use of LCI (adjusted odds ratio [aOR] 1.63, 95%CI 1.10-2.41), experienced endoscopists (aOR 1.94, 95%CI 1.25-3.00), use of transparent cap (aOR 1.75, 95%CI 1.09-2.81), and longer withdrawal time (aOR 1.06, 95%CI 1.03-1.10) were independently associated with SSL detection. Synchronous adenoma detection (aOR 1.89, 95%CI 1.20-2.99) was also predictive of SSL detection. CONCLUSION: The prevalence of SSLs in Asia is 4.0%. Use of LCI or a transparent cap, greater endoscopist experience, and longer withdrawal time were all associated with increased SSL detection.

Discovery of the Clinical Candidate Sonrotoclax (BGB-11417), a Highly Potent and Selective Inhibitor for Both WT and G101V Mutant Bcl-2.

The approval of venetoclax, a B-cell lymphoma-2 (Bcl-2) selective inhibitor, for the treatment of chronic lymphocytic leukemia demonstrated that the antiapoptotic protein Bcl-2 is a druggable target for B-cell malignancies. However, venetoclax's limited potency cannot produce a strong, durable clinical benefit in other Bcl-2-mediated malignancies (e.g., diffuse large B-cell lymphomas) and multiple recurrent Bcl-2 mutations (e.g., G101V) have been reported to mediate resistance to venetoclax after long-term treatment. Herein, we described novel Bcl-2 inhibitors with increased potency for both wild-type (WT) and mutant Bcl-2. Comprehensive structure optimization led to the clinical candidate BGB-11417 (compound 12e, sonrotoclax), which exhibits strong in vitro and in vivo inhibitory activity against both WT Bcl-2 and the G101V mutant, as well as excellent selectivity over Bcl-xL without obvious cytochrome P450 inhibition. Currently, BGB-11417 is undergoing phase II/III clinical assessments as monotherapy and combination treatment.

Abnormal energy metabolism in the pathogenesis of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a severe autoimmune disease with significant socioeconomic impact worldwide. Orderly energy metabolism is essential for normal immune function, and disordered energy metabolism is increasingly recognized as an important contributor to the pathogenesis of SLE. Disorders of energy metabolism are characterized by increased reactive oxygen species, ATP deficiency, and abnormal metabolic pathways. Oxygen and mitochondria are critical for the production of ATP, and both mitochondrial dysfunction and hypoxia affect the energy production processes. In addition, several signaling pathways, including mammalian target of rapamycin (mTOR)/adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) signaling and the hypoxia-inducible factor (HIF) pathway also play important regulatory roles in energy metabolism. Furthermore, drugs with clear clinical effects on SLE, such as sirolimus, metformin, and tacrolimus, have been proven to improve the disordered energy metabolism of immune cells, suggesting the potential of targeting energy metabolism for the treatment of SLE. Moreover, several metabolic modulators under investigation are expected to have potential therapeutic effects in SLE. This review aimed to gain insights into the role and mechanism of abnormal energy metabolism in the pathogenesis of SLE, and summarizes the progression of metabolic modulator in the treatment of SLE.

Observation of bound valence excited electronic states of deprotonated 2-hydroxytriphenylene using photoelectron, photodetachment, and resonant two-photon detachment spectroscopy of cryogenically cooled anions.

Polycyclic aromatic hydrocarbons (PAHs) are common atmospheric pollutants, and they are also ubiquitous in the interstellar medium. Here, we report the study of a complex O-containing PAH anion, the deprotonated 2-hydroxytriphenylene (2-OtPh-), using high-resolution photoelectron imaging and photodetachment spectroscopy of cryogenically cooled anions. Vibrationally resolved photoelectron spectra yield the electron affinity of the 2-OtPh radical as 2.629(1) eV and several vibrational frequencies for its ground electronic state. Photodetachment spectroscopy reveals bound valence excited electronic states for the 2-OtPh- anion, with unprecedentedly rich vibronic features. Evidence is presented for a low-lying triplet state (T1) and two singlet states (S1 and S2) below the detachment threshold. Single-color resonant two-photon photoelectron spectroscopy uncovers rich photophysics for the 2-OtPh- anion, including vibrational relaxation in S1, internal conversion to the ground state of 2-OtPh-, intersystem crossing from S2 to T1, and a long-lived autodetaching shape resonance about 1.3 eV above the detachment threshold. The rich electronic structure and photophysics afforded by the current study suggest that 2-OtPh- would be an interesting system for pump-probe experiments to unravel the dynamics of the excited states of this complex PAH anion.

Formation of Supernarrow Borophene Nanoribbons.

Borophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self-contained to ∼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post-passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs' zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes.

Predicting delayed extubation and transfer to the intensive care unit in children undergoing posterior fusion surgery for scoliosis : A retrospective observational study.

BACKGROUND: Delayed extubation and transfer to the intensive care unit (ICU) in children undergoing major scoliosis surgery may increase postoperative complications, prolong hospital stay, and increase medical expenses; however, whether a child will require delayed extubation or transfer to the ICU after scoliosis orthopedic surgery is not fully understood. In this study, we reviewed the risk factors for delayed extubation and transfer to the ICU after scoliosis orthopedic surgery in children. METHOD: The electronic medical records of pediatric patients (≤ 18 years) who underwent posterior spinal fusion surgery between January 2018 and November 2021 were reviewed and analyzed. Patient characteristics (age, sex, body mass index, American Society of Anesthesiologists, ASA, grade, preoperative lung function, and congenital heart disease), preoperative Cobb angle, scoliosis type, correction rate, vertebral fusion segments, pedicle screws, surgical osteotomy, intraoperative bleeding, intraoperative allogeneic transfusion, intraoperative hemoglobin changes, intraoperative mean arterial pressure changes, intraoperative tidal volume (ml/kg predicted body weight), surgical time, postoperative extubation, and transfer to the ICU were collected. The primary outcomes were delayed extubation and transfer to the ICU. Multivariate logistic regression models were used to determine the risk factors for delayed extubation and ICU transfer. RESULTS: A total of 246 children who satisfied the inclusion criteria were enrolled in this study, of whom 23 (9.3%) had delayed extubation and 81 (32.9%) were transferred to the ICU after surgery. High ASA grade (odds ratio [OR] 5.42; 95% confidence interval [CI] 1.49-19.78; p = 0.010), high Cobb angle (OR 1.04; 95% CI 1.02-1.07; p < 0.001), moderate to severe pulmonary dysfunction (OR 10.9; 95% CI 2.00-59.08; p = 0.006) and prolonged surgical time (OR 1.01; 95% CI 1.00-1.03; p = 0.040) were risk factors for delayed extubation. A high Cobb angle (OR 1.02; 95% CI 1.01-1.04; p = 0.004), high intraoperative bleeding volume (OR 1.06; 95% CI 1.03-1.10; p = 0.001), allogeneic transfusion (OR 3.30; 95% CI 1.24-8.83; p = 0.017) and neuromuscular scoliosis (OR 5.38; 95% CI 1.59-18.25; p = 0.007) were risk factors for transfer to the ICU. A high Cobb angle was a risk factor for both delayed extubation and ICU transfer. Age, sex, body mass index, number of vertebral fusion segments, correction rate, and intraoperative tidal volume were not associated with delayed postoperative extubation and ICU transfer. CONCLUSION: The most common risk factor for delayed extubation and ICU transfer in pediatric patients who underwent posterior spinal fusion was a high Cobb angle. Determining risk factors for a poor prognosis may help optimize perioperative respiratory management strategies and planning of postoperative care for children undergoing complicated spinal surgery.

High-Resolution Photoelectron Imaging of Cryogenically Cooled BiB2- and BiB3- Bismuth-Boron Clusters.

We report a high-resolution photoelectron imaging study of cryogenically cooled BiB2- and BiB3- clusters. Vibrational features are completely resolved for the ground-state detachment transitions, providing critical information about the structures of the anionic clusters and their corresponding neutrals. The electron affinities of BiB2 and BiB3 are accurately measured to be 2.174(1) and 2.121(1) eV, respectively. The B-B and Bi-B stretching frequencies are measured to be 1262 and 476 cm-1, respectively, in the ground state of BiB2. Three vibrational frequencies are measured for the ground state of BiB3: 1194 cm-1 (B-B stretching), 782 cm-1 (B-B stretching), and 339 cm-1 (Bi-B stretching). Both BiB2- and BiB3- and their neutral ground states are found to have planar C2v structures in which the Bi atom bridges two B atoms. BiB2- is found to have a triplet spin state (3B2), consistent with its complicated photoelectron spectra, whereas BiB3- is a doublet (2B1) and neutral BiB3 is closed shell (1A1). Both BiB2 and BiB3 consist of peripheral localized Bi-B and B-B σ bonds and delocalized π and σ bonds.

Electronic Control of the Position of the Pb Atom on the Surface of B8 Borozene in the PbB8 Cluster.

Spontaneous symmetry-breaking is common in chemical and physical systems. Here, we show that by adding an electron to the C7v PbB8 cluster, which consists of a planar B8 disk with the Pb atom situated along the C7 axis, the Pb atom spontaneously moves to the off-axis position in the PbB8- anion. Photoelectron spectroscopy of PbB8- reveals a broad ground-state transition and a large energy gap, suggesting a highly stable closed-shell PbB8 borozene complex and a significant geometry change upon electron detachment. Quantum chemistry calculations indicate that the lowest unoccupied molecular orbital of the C7v PbB8 cluster is a degenerate π orbital mainly consisting of the Pb 6px and 6py atomic orbitals. Occupation of one of the 6p orbitals spontaneously break the C7v symmetry in the anion due to the Jahn-Teller effect. The large amplitude of the position change of Pb in PbB8- relative to PbB8 is surprising owing to bonding interactions between the Pb 6p orbital with the π orbital of the B8 borozene.