Bioinformatics investigation of adaptive immune-related genes in peri-implantitis and periodontitis: Characteristics and diagnostic values.

BACKGROUND: Peri-implantitis and periodontitis have similar immunological bioprocesses and inflammatory phenotypes. In the inflammatory process, the adaptive immune cells can drive the development of disease. This research investigated the differences and diagnostic significance of peri-implantitis and periodontitis in adaptive immune responses. METHODS: We acquired four GEO datasets of gene expressions in surrounding tissues in healthy person, healthy implant, periodontitis, and peri-implantitis patients. The structural characteristics and enrichment analyses of differential expression genes were examined. The adaptive immune landscapes in peri-implantitis and periodontitis were then evaluated using single sample gene set enrichment analysis. The STRING database and Cytoscape were used to identify adaptive hub genes, and the ROC curve was used to verify them. Finally, qRT-PCR method was used to verify the expression level of Hub gene in activated T cells on the titanium-containing or titanium-free culture plates. RESULTS: At the transcriptome level, the data of healthy implant, peri-implantitis and periodontitis were highly dissimilar. The peri-implantitis and periodontitis both exhibited adaptive immune response. Except for the activated CD4+T cells, there was no significant difference in other adaptive immune cells between peri-implantitis and periodontitis. In addition, correlation analysis showed that CD53, CYBB, and PLEK were significantly positively linked with activated CD4+T cells in the immune microenvironment of peri-implantitis, making them effective biomarkers to differentiate it from periodontitis. CONCLUSIONS: Peri-implantitis has a uniquely immunogenomic landscape that differs from periodontitis. This study provides new insights and ideas into the activated CD4+T cells and hub genes that underpin the immunological bioprocess of peri-implantitis.

Enhancing the reversibility of the chemical evolution of the Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode via a simple pre-oxidation process.

For developing commercially viable LiNi1-x-yMnxCoyO2 (NCM), it is necessary to alleviate the irreversible chemical process upon Li-ion insertion/extraction, which primarily accounts for prevailing capacity loss, impedance buildup as well as low columbic efficiency. To resolve this issue, we herein propose a simple but novel method to alter the chemical composition by a facile treatment of H2O2, which remarkably reduces the cation mixing of Li+/Ni2+ and residual lithium on the cathode. The tailored composition contributes great resistance to the structural reconstruction and enhancement in structural reversibility, as shown by in situ Raman and high-resolution transmission electron microscope (HRTEM) results. Thus, the modified sample outperforms the pristine one; it exhibits cyclability with 95.7% capacity retention over 300 cycles, high columbic efficiency and enhanced rate capability.

NLRP3/miR-223-3p axis attenuates neuroinflammation induced by chronic intermittent hypoxia.

Obstructive sleep apnea (OSA) is mainly characterized by chronic intermittent hypoxia (CIH) with multiple brain injuries. Nucleotide oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome is considered the most important factor inducing and maintaining inflammation. However, the role of NLRP3 and its underlying mechanism in CIH-elicited neuroinflammation remains unclear. We constructed an OSA-related CIH in vivo model and assessed the rats' cognitive behavior in the Morris water maze. The combination of miR-223-3p and NLRP3 was confirmed by the TargetScan database, double luciferase reporter gene experiment, and RNA immunoprecipitation (RIP) experiment. Western blot and ELISA assay were used to analyze the effects of miR-223-3p targeting NLRP3 on the expression of pyroptotic or inflammatory factors in vivo in CIH rats. Severe cognitive impairment was observed in rats at week 6 post-treatment, with increased inflammatory factors in the blood and hippocampus, heightened NLRP3 expression, and low miR-223-3p levels. And the good binding activity of the two was confirmed by dual luciferase reporter and RIP experiments. Next, we found that silencing NLRP3 or overexpression of miR-223-3p in the CIH model could improve cognitive deficits and reduce the level of proinflammatory factors and pyroptosis factors in rats. Finally, based on silencing NLRP3 or overexpression miR-223-3p, we confirmed that there was a regulatory relationship between miR-223-3p and NLRP3. Our results suggested that the NLRP3/ miR-223-3p axis played a role in attenuating CIH-induced neuroinflammation.

Chemical carcinogens: implications for cancer treatment.

Carcinogen exposure has been associated with enhanced cancer immunogenicity that is often attributed to neoantigen generation. However, the broader, neoantigen-independent impact of carcinogens on immune responses to cancer cells remains underexplored. In this issue of the JCI, Huang et al. uncover a mechanism wherein carcinogen-treated cancer cells exhibit an inability to establish an immunosuppressive tumor microenvironment (TME) due to reduced M-CSF expression. Intriguingly, the so-called carcinogen-induced tumor-associated macrophages (TAMs) within this TME exhibited anti-tumor properties instead of the conventional immunosuppressive phenotype. This phenomenon extended to human lung cancers, as evidenced by TAM reprogramming in smokers versus nonsmokers. This study substantially advances our understanding of carcinogen-mediated effects on cancer immunogenicity, potentially redirecting approaches to cancer immunotherapy.

3D printing of inorganic nanomaterials by photochemically bonding colloidal nanocrystals.

3D printing of inorganic materials with nanoscale resolution offers a different materials processing pathway to explore devices with emergent functionalities. However, existing technologies typically involve photocurable resins that reduce material purity and degrade properties. We develop a general strategy for laser direct printing of inorganic nanomaterials, as exemplified by more than 10 semiconductors, metal oxides, metals, and their mixtures. Colloidal nanocrystals are used as building blocks and photochemically bonded through their native ligands. Without resins, this bonding process produces arbitrary three-dimensional (3D) structures with a large inorganic mass fraction (~90%) and high mechanical strength. The printed materials preserve the intrinsic properties of constituent nanocrystals and create structure-dictated functionalities, such as the broadband chiroptical responses with an anisotropic factor of ~0.24 for semiconducting cadmium chalcogenide nanohelical arrays.

Tumor-specific cholinergic CD4+ T lymphocytes guide immunosurveillance of hepatocellular carcinoma.

Cholinergic nerves are involved in tumor progression and dissemination. In contrast to other visceral tissues, cholinergic innervation in the hepatic parenchyma is poorly detected. It remains unclear whether there is any form of cholinergic regulation of liver cancer. Here, we show that cholinergic T cells curtail the development of liver cancer by supporting antitumor immune responses. In a mouse multihit model of hepatocellular carcinoma (HCC), we observed activation of the adaptive immune response and induction of two populations of CD4+ T cells expressing choline acetyltransferase (ChAT), including regulatory T cells and dysfunctional PD-1+ T cells. Tumor antigens drove the clonal expansion of these cholinergic T cells in HCC. Genetic ablation of Chat in T cells led to an increased prevalence of preneoplastic cells and exacerbated liver cancer due to compromised antitumor immunity. Mechanistically, the cholinergic activity intrinsic in T cells constrained Ca2+-NFAT signaling induced by T cell antigen receptor engagement. Without this cholinergic modulation, hyperactivated CD25+ T regulatory cells and dysregulated PD-1+ T cells impaired HCC immunosurveillance. Our results unveil a previously unappreciated role for cholinergic T cells in liver cancer immunobiology.

Identification of an Optimized Receptor-Binding Domain Subunit Vaccine against SARS-CoV-2.

Current vaccine efforts to combat SARS-CoV-2 are focused on the whole spike protein administered as mRNA, viral vector, or protein subunit. However, the SARS-CoV-2 receptor-binding domain (RBD) is the immunodominant portion of the spike protein, accounting for 90% of serum neutralizing activity. In this study, we constructed several versions of RBD and together with aluminum hydroxide or DDA (dimethyldioctadecylammonium bromide)/TDB (d-(+)-trehalose 6,6'-dibehenate) adjuvant evaluated immunogenicity in mice. We generated human angiotensin-converting enzyme 2 knock-in mice to evaluate vaccine efficacy in vivo following viral challenge. We found that 1) subdomain (SD)1 was essential for the RBD to elicit maximal immunogenicity; 2) RBDSD1 produced in mammalian HEK cells elicited better immunogenicity than did protein produced in insect or yeast cells; 3) RBDSD1 combined with the CD4 Th1 adjuvant DDA/TDB produced higher neutralizing Ab responses and stronger CD4 T cell responses than did aluminum hydroxide; 4) addition of monomeric human Fc receptor to RBDSD1 (RBDSD1Fc) significantly enhanced immunogenicity and neutralizing Ab titers; 5) the Beta version of RBDSD1Fc provided a broad range of cross-neutralization to multiple antigenic variants of concern, including Omicron; and 6) the Beta version of RBDSD1Fc with DDA/TDB provided complete protection against virus challenge in the knock-in mouse model. Thus, we have identified an optimized RBD-based subunit vaccine suitable for clinical trials.

Prevalence and Risk Factors of Anxiety Among Adult Patients with Chronic Pharyngitis in Wuhu, China.

Objective: Chronic pharyngitis (CP) is a common disease, which has a long duration and a wide range of onset. Anxiety is considered to be a common complication in patients with CP. The purpose of this study was to evaluate the anxiety level and potentially influencing factors in patients with CP, to provide insights for the management of anxiety in patients with CP. Methods: A total of 104 adult patients with CP meeting the inclusion/exclusion criteria were enrolled from a single center in Wuhu, China between October 2015 and December 2016. A Self-rating Anxiety Scale (SAS) was used to measure the status of anxiety. The relationship between SAS scores and illness period in patients with CP was analyzed by Pearson correlation test. Univariate analysis and binary logistic regression analysis were performed to analyze the risk factors of anxiety in patients with CP. Results: The average SAS score of 104 patients with CP was (44.17 ± 8.38), including 82 cases (78.85%) without anxiety and 22 cases (21.15%) with anxiety. Moreover, the illness period was found to be positively related to SAS scores in patients with CP (r = 0.378, P = 0.001). Furthermore, the results of univariate analysis showed that there were significant differences in anxiety state among CP patients with different age, illness period, source of treatment payment, and marital status (P < 0.05). Additionally, the results of binary logistic regression analysis showed that age, source of treatment payment, and marital status were the independent risk factors affecting the anxiety status of patients with CP (P < 0.05). Conclusion: These results suggested that CP patients with advanced age, self-pay, and unmarried status had higher risk for anxiety.

Mandibular resection and defect reconstruction guided by a contour registration-based augmented reality system: A preclinical trial.

The aim of this study was to verify the feasibility and accuracy of a contour registration-based augmented reality (AR) system in jaw surgery. An AR system was developed to display the interaction between virtual planning and images of the surgical site in real time. Several trials were performed with the guidance of the AR system and the surgical guide. The postoperative cone beam CT (CBCT) data were matched with the preoperatively planned data to evaluate the accuracy of the system by comparing the deviations in distance and angle. All procedures were performed successfully. In nine model trials, distance and angular deviations for the mandible, reconstructed fibula, and fixation screws were 1.62 ± 0.38 mm, 1.86 ± 0.43 mm, 1.67 ± 0.70 mm, and 3.68 ± 0.71°, 5.48 ± 2.06°, 7.50 ± 1.39°, respectively. In twelve animal trials, results of the AR system were compared with the surgical guide. Distance deviations for the bilateral condylar outer poles were 0.93 ± 0.63 mm and 0.81 ± 0.30 mm, respectively (p = 0.68). Distance deviations for the bilateral mandibular posterior angles were 2.01 ± 2.49 mm and 2.89 ± 1.83 mm, respectively (p = 0.50). Distance and angular deviations for the mandible were 1.41 ± 0.61 mm, 1.21 ± 0.18 mm (p = 0.45), and 6.81 ± 2.21°, 6.11 ± 2.93° (p = 0.65), respectively. Distance and angular deviations for the reconstructed tibiofibular bones were 0.88 ± 0.22 mm, 0.84 ± 0.18 mm (p = 0.70), and 6.47 ± 3.03°, 6.90 ± 4.01° (p = 0.84), respectively. This study proposed a contour registration-based AR system to assist surgeons in intuitively observing the surgical plan intraoperatively. The trial results indicated that this system had similar accuracy to the surgical guide.

Synthesis of Sequence-specific Poly(ester-carbonate) Copolymers via Chemoselective Terpolymerization Controlled by the Stoichiometric Ratio of Phosphazene/Triethylborane.

Chemoselective terpolymerization can produce polymer materials with diverse compositions and sequential structures, and thus have attracted considerable attention in the field of polymer synthesis. However, the intrinsic complexity of three-component system also brings great chanllenge, in regard to the reactivity and selectivity of different monomers. Herein, we report the terpolymerization of CO2 /epoxide/anhydride by a binary organocatalytic C3 N3 -Py-P3 /TEB (triethylborane) system. Both the activity and chemoselectivity were highly dependent upon the molar ratio of C3 N3 -Py-P3 to TEB, and sequence-controlled poly(ester-carbonate) copolymers were readily synthesized through one-pot/one-step methodology by tuning the stoichiometric ratio of phosphazene/TEB. In particular, C3 N3 -Py-P3 /TEB with a molar ratio of 1/0.5 exhibited an unprecedentedly high chemoselectivity for ring-opening alternating copolymerization (ROAC) of cyclohexene oxide (CHO) and phthalic anhydride (PA) first and then ROAC of CO2 /CHO. Thus, well-defined triblock polycarbonate-b-polyester-b-polycarbonate copolymers can be produced from the mixture of CO2 , CHO and PA using a bifunctional initiator. With C3 N3 -Py-P3 /TEB=1/1, tapered copolymers were obtained, while random copolymers with high content of polycarbonate (PC) were synthesized with further increasing the amount of TEB. The mechanism of the unexpected chemoselectivity was further investigated by DFT calculations.

Non-Invasive and Minute-Frequency 3D Tomographic Imaging Enabling Long-Term Spatiotemporal Observation of Single Cell Fate.

Non-invasive and rapid imaging technique at subcellular resolution is significantly important for multiple biological applications such as cell fate study. Label-free refractive-index (RI)-based 3D tomographic imaging constitutes an excellent candidate for 3D imaging of cellular structures, but its full potential in long-term spatiotemporal cell fate observation is locked due to the lack of an efficient integrated system. Here, a long-term 3D RI imaging system incorporating a cutting-edge white light diffraction phase microscopy module with spatiotemporal stability, and an acoustofluidic device to roll and culture single cells in a customized live cell culture chamber is reported. Using this system, 3D RI imaging experiments are conducted for 250 cells and demonstrate efficient cell identification with high accuracy. Importantly, long-term and frequency-on-demand 3D RI imaging of K562 and MCF-7 cancer cells reveal different characteristics during normal cell growth, drug-induced cell apoptosis, and necrosis of drug-treated cells. Overall, it is believed that the proposed 3D tomographic imaging technique opens up a new avenue for visualizing intracellular structures and will find many applications such as disease diagnosis and nanomedicine.

ESBR Nanocomposites Filled with Monodisperse Silica Modified with Si747: The Effects of Amount and pH on Performance.

To prepare silica/rubber composites for low roll resistance tires, a novel strategy was proposed in this study, in which autonomous monodisperse silica (AS) was prepared and modified using 3-mercaptopropyloxy-methoxyl-bis(nonane-pentaethoxy) siloxane (Si747), after which silica/emulsion styrene butadiene rubber (ESBR) master batches were produced using the latex compounding technique. Meanwhile, the commercial precipitated silica (PS) was introduced as a control. In this study, the effects of amount of Si747 and pH value on the properties of the silica/ESBR composites were systematically analyzed. Thermal gravimetric analysis (TGA) and Fourier transform infrared (FTIR) results indicated that Si747 reduced the silanol group by chemical grafting and physical shielding, and the optimum amounts of Si747 for AS and PS modification were confirmed to be 15% and 20%, respectively. Under a pH of 9, ESBR/modified AS (MAS) composites with 15% Si747 presented better silica dispersion and a weaker Payne effect, compared with ESBR/modified PS (MPS) composites with 20% Si747. Meanwhile, in terms of dynamic properties, the ESBR/MAS composites exhibited a better balance of lower rolling resistance and higher wet skid resistance than the ESBR/MPS composites.

Dinuclear Group 4 Metal Complexes Bearing Anthracene-Bridged Bifunctional Amido-Ether Ligands: Remarkable Metal Effect and Cooperativity toward Ethylene/1-Octene Copolymerization.

Two types of bifunctional amido-ether ligands (syn-L and anti-L) with the rigid anthracene skeleton were designed to support dinuclear group 4 metal complexes. All organic ligands and organometallic complexes (syn-M2 and anti-M2; M = Hf, Zr, and Ti) were fully characterized by 1H and 13C NMR spectroscopies and elemental analyses. The anti-Hf2 complex showed two confirmations at room temperature with C2-symmetry or S2-symmetry that can inter-exchange, as indicated by VT NMR, while only a C2-symmetric isomer was observed for syn-Hf2 complex at room temperature. However, for Zr and Ti analogues, both syn and anti complexes exhibited only one conformation at room temperature. The molecular structures of complexes syn-Hf2, anti-Hf2, and syn-Ti2 in the solid state were further determined by single-crystal X-ray diffraction, revealing the distances between two metal centers in syn-M2 from 7.138 Å (syn-Ti2) to 7.321 Å (syn-Hf2) but a much farther separation in anti-M2 (8.807 Å in C2-symmetric anti-Hf2). The mononuclear complex (2-CH3O-C6H4-N-C14H9)Zr(NMe2)3 (mono-Zr1) was also prepared for control experiments. In the presence of alkyl aluminum (AlEt3) as the alkylating agent and trityl borate ([Ph3C][B(C6F5)4]) as the co-catalyst, all metal complexes were tested for copolymerization of ethylene with 1-octene at high temperature (130 °C). The preliminary polymerization results revealed that the activity was highly dependent upon the nature of metal centers, and syn-Zr2 showed the highest activity of 9600 kg(PE)·mol-1 (Zr)·h-1, which was about 17- and 2.2-fold higher than those of syn-Hf2 and syn-Ti2, respectively. Benefitting from both steric proximity and electronical interaction of two metal centers, syn-Zr2 exhibited significant cooperativity in comparison to anti-Zr2 and mono-Zr1, with regard to activity and molecular weight and 1-octene incorporation of resultant copolymers.

The H3K27 demethylase controls the lateral line embryogenesis of zebrafish.

BACKGROUND: Kdm6b, a specific histone 3 lysine 27 (H3K27) demethylase, has been reported to be implicated in a variety of developmental processes including cell differentiation and cell fate determination and multiple organogenesis. Here, we regulated the transcript level of kdm6bb to study the potential role in controlling the hearing organ development of zebrafish. METHODS: A morpholino antisense oligonucleotide (MO) strategy was used to induce Kdm6b deficiency; immunohistochemical staining and in situ hybridization analysis were conducted to figure out the morphologic alterations and embryonic mechanisms. RESULTS: Kdm6bb is expressed in the primordium and neuromasts at the early stage of zebrafish embryogenesis, suggesting a potential function of Kdm6b in the development of mechanosensory organs. Knockdown of kdm6bb severely influences the cell migration and proliferation in posterior lateral line primordium, abates the number of neuromasts along the trunk, and mRNA-mediated rescue test can partially renew the neuromasts. Loss of kdm6bb might be related to aberrant expressions of chemokine genes encompassing cxcl12a and cxcr4b/cxcr7b in the migrating primordium. Moreover, inhibition of kdm6bb reduces the expression of genes in Fgf signaling pathway, while it increases the axin2 and lef1 expression level of Wnt/ß-catenin signaling during the migrating stage. CONCLUSIONS: Collectively, our results revealed that Kdm6b plays an essential role in guiding the migration of primordium and in regulating the deposition of zebrafish neuromasts by mediating the gene expression of chemokines and Wnt and Fgf signaling pathway. Since histone methylation and demethylation are reversible, targeting Kdm6b may present as a novel therapeutic regimen for hearing disorders.

Development and Validation of a Modified QuEChERS Method for Simultaneous Analysis of 250 Flavor Constituents in Tobacco by Gas Chromatography Tandem Mass Spectrometry.

BACKGROUND: Flavor constituents play an important role in the flavor characteristics of tobacco leaves and cigarettes. Sensitive, selective, and high-throughput multi-analyte analytical methods are needed to satisfy the demand for analyzing trace-level flavor constituents in tobacco. However, trace analysis of multi-targets in a complex tobacco matrix is significantly challenging. OBJECTIVE: This study was undertaken to develop and validate a fast, selective, sensitive, and accurate GC-tandem mass spectrometry (GC-MS/MS) method for the simultaneous analysis of 250 flavor constituents in tobacco using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction procedure and backflushing technique. METHODS: The samples were extracted with a mixture of acetonitrile and phosphate buffer. GC-MS/MS served as a reliable tool to quantify the flavor constituents due to its high sensitivity, selectivity, and good repeatability. RESULTS: Our evaluation showed that 243 flavor constituents presented good linearity. Average recoveries of 216 target compounds in tobacco ranged from 70 to 120% with RSDs less than 20% at three fortification levels. The limits of quantitation of 225 and 25 compounds were in the range of 2-50 and 51-112 µg/kg, respectively. This method was then successfully applied to the analysis of 15 commercial cigarette samples with different style characteristics. CONCLUSION: The modified QuEChERS method worked very well for a wide range of flavor constituents that have not been reported by QuEChERS pretreatment previously, and the use of concurrent backflushing offered significant increase in system robustness and sample throughput. The method greatly improved the detection performance and the range of the flavor constituents, and proved to be more accurate, sensitive, selective, convenient, and practical than the reported method, and thus, can be applied in routine analysis. HIGHLIGHTS: A validated QuEChERS-based GC-MS/MS method for multiple flavor constituents analysis in tobacco was reported for the first time. The use of concurrent backflushing markedly improved the instrument robustness and sample throughput.

Chinese familial central precocious puberty with hyperuricemia due to recurrent DLK1 mutation: Case report and review of the literature.

BACKGROUND: Central precocious puberty (CPP) is a precocious puberty due to premature activation of the hypothalamic-pituitary-gonadal axis (HPG). MKRN3 defects are well-known causes of CPP, while DLK1 mutations were recently identified in a few patients with CPP. METHODS: The study was approved by the Institutional Review and the scientific committee of the hospital. The clinical data were collected. Whole-exome sequencing (WES) was performed to detect causative variants. Key words 'DLK1', 'MKRN3', and "central precocious puberty" were used for literature search in PubMed, Google Scholar, HGMD, and OMIM databases. RESULTS: The patient, a male, whose puberty began before age nine, had significant metabolic abnormalities including overweight, hyperlipidemia, and hyperuricemia. WES detected a recurrent frame-shift mutation, NM_003836.5:c.479delC(p.P160fs*50) in DLK1 in the patient and his father. CONCLUSION: The familial DLK1-CPP was identified in China for the first time, which supported that short stature is predicted in patients with CPP without GnRHa treatment. Therefore, we recommend that children with DLK1-CPP should be treated as early as possible to improve adult height. The patient in this study had persistent hyperuricemia, further suggests that this antiadipogenic factor represents a link between reproduction and metabolism.

Just-in-Time Learning-Integrated Partial Least-Squares Strategy for Accurately Predicting 71 Chemical Constituents in Chinese Tobacco by Near-Infrared Spectroscopy.

Near-infrared spectroscopy has been widely used to characterize the chemical composition of tobacco because it is fast, economical, and nondestructive. However, few predictive models perform ideally when applied to large spectral libraries of tobacco and its various chemical indicators. In this study, the just-in-time learning-integrated partial least-squares (JIT-PLS) modeling strategy was applied for the first time to quantitatively analyze 71 chemical components in Chinese tobacco. Approximately 18000 tobacco samples from China were analyzed to find appropriately similar measurements and propose suitable and flexible similar subsets from the calibration for each test sample. In total, 879 representative aged tobacco leaf samples and 816 cigarette samples were used as external instances to evaluate the practical predicting ability of the proposed method. The most suitable similar subsets for each test sample could be selected by limiting the Euclidean distance and number of similar subsets to 0-3.0 × 10-9 and 10-300, respectively. The majority of the JIT-PLS models performed significantly better than traditional PLS models. Specifically, using JIT-PLS instead of traditional PLS models increased the R 2 values from 0.347-0.984 to 0.763-0.996, and from 0.179-0.981 to 0.506-0.989 for the prediction of 67 and 71 components in aged tobacco leaf and cigarette samples, respectively. Good prediction ability was demonstrated for routine chemical components, polyphenolic compounds, organic acids, and other compounds, with the mean ratios of prediction to deviation (RPDmean) being 7.74, 4.39, 4.05, and 5.48, respectively). The proposed methodology could simultaneously determine 67 major components in large and complicated tobacco spectral libraries with high precision and accuracy, which will assist tobacco and cigarette quality control in collecting as well as processing stages.

Accuracy improvement of determination of seven minor tobacco alkaloids in mainstream cigarette smoke using analyte protectants by gas chromatography-mass spectrometry.

Tobacco alkaloids are important precursors of carcinogenic tobacco-specific nitrosamines. Therefore, accurate quantification of tobacco alkaloids is highly important. This study investigates the compensation effects of novel analyte protectants (APs) for matrix effects (MEs) to determine seven minor tobacco alkaloids (nornicotine, myosmine, anabasine, anatabine, nicotyrine, 2,3'-bipyridine, and cotinine) in mainstream cigarette smoke with high accuracy and robustness. By comparing the heights and shapes of the chromatographic peaks before and after the addition of APs to standard solutions prepared in dichloromethane and cigarette smoke solutions, the compensation effects of 12 APs and their combinations on the MEs of seven minor tobacco alkaloids were evaluated, and the best combination of 2-pyridylethylamine (2 mg/mL)+1,2-decanediol (1 mg/mL) was identified. This AP combination could effectively improve the shapes and increase the heights (by 7-371%) of chromatographic peaks for standard solutions prepared in dichloromethane and cigarette smoke solutions. Before the addition of this AP combination, the slope ratios of the calibration curves for two types of standard solutions of the seven target chemicals were 71.4-159.8%, while they were 87.4-105.6% after the addition, indicating that this AP combination reduced the matrix difference between pure solvent and cigarette smoke solution. After adding the AP combination, the standard curves of solutions prepared in dichloromethane showed good linearity (r2 ≥ 0.999), the spiked recoveries were between 80.9% and 119.6%, and the inter- and intraday precisions were between 1.5-9.5% and 3.1-8.5%, respectively. Three commercial cigarette samples and one mixed standard solution were also tested under four different instrument working conditions to verify the long-term accuracy and ruggedness of the approach in routine real-world analysis of the method. The results showed that the RSD values were higher (3.5-25.4%) without the AP combination than that (<6.7%) with the AP combination. Because of its high accuracy, precision, and robustness, this method has good practical prospects.

Kinesin spindle protein inhibitor exacerbates cisplatin-induced hair cell damage.

There is emerging evidence indicating that Kinesin family, plays vital roles in influencing the growth of axons, interference with the progression of tumor. However, the function of Kinesin member in the auditory organs remains unknown. SB743921, a kinesin spindle protein (KSP) inhibitor, was applied in mouse organ of Corti and House Ear Institute-Organ of Corti 1 (HEI-OC1) cell line to examine the role of KSP in auditory system with and without cisplatin damage. Cell Counting Kit-8 (CCK-8) and Lactase dehydrogenase (LDH) release assay were conducted to evaluate cell activity and toxicity. Pretreatment with SB743921 increased the sensitivity of HEI-OC1 cells to cisplatin ototoxicity through promoting cell apoptosis and deteriorating superoxide generation mediated damage from cisplatin. SB743921 also enhanced cisplatin induced hair cell damage in explants of mouse cochleae in vitro. Furthermore, the combined N-acetylcysteine (NAC) treatment with cisplatin or with cisplatin and SB743921 both completely rescued the reduced number of hair cells impaired by cisplatin, confirming the strengthening function of superoxide accumulation by SB743921 after cisplatin treatment. Inhibition of kinesin spindle protein enhanced the susceptibility of hair cells to cisplatin induced damage in mouse cochlear explants and HEI-OC1 cells, indicating that kinesin spindle protein might be an unprecedented target to weaken the ototoxicity of platinum medicaments.

Highly Active Organocatalysts for Stereoselective Ring-Opening Polymerization of Racemic Lactide at Room Temperature.

Although significant advances have been achieved, highly stereocontrolled polymerization using organocatalysts is still a great challenge, such as ring-opening polymerization of racemic lactide (rac-LA) for the synthesis of stereoregular polylactide (PLA). In this context, a series of binary organocatalysts consisting of different phosphazenes (CTPB, C3N3-Me-P3, C3N3-Py-P3, t-BuP2, and t-BuP4) and achiral ureas (U1-U6) were applied for the stereocontrolled ROP of rac-LA under mild conditions. It is remarkable that C3N3-Py-P3/U4 with the compatible basicity/acidity showed both high activity (92% conversion within 10 min) and great stereoselectivity (Pm = 0.92) at room temperature (20 °C), and the resultant stereoblock PLA had predictable molar mass, narrow distribution (D = 1.07), and high melting temperature (Tm = 190 °C). Interactions involved among phosphazene, urea, and initiator were investigated by an in situ NMR technique. It was found that C3N3-Py-P3 reacted with benzyl alcohol (BnOH) to form a relatively loose ion pair in the presence of U4, which accounted for both high activity and stereoselectivity. Kinetics studies for different LA monomers at 20 °C showed kobs-1 (rac-LA) = 0.212 min-1, kobs-1 (D-LA) = 0.311 min-1, and kobs-1 (L-LA) = 0.317 min-1, indicative of the chain end control mechanism for stereocontrolled ROP.