Thermal Methane Conversion to Formaldehyde Mediated by NiAlO3+ in the Gas Phase.

Understanding the active sites and reaction mechanisms of Ni-based catalysts, such as Ni/Al2O3, toward methane is a prerequisite for improving their rational design. Here, the gas-phase reactivity of NiAlO3+ cations toward CH4 is studied using mass spectrometry combined with density functional theory. Similar to our previous study on NiAl2O4+, we find evidence for the formation of both the methyl radical (CH3•) and formaldehyde (CH2O). The first step for methane activation is hydrogen atom abstraction by the terminal oxygen radical Ni(O)2AlO• from methane forming a [Ni(O)2AlOH+, •CH3] complex and leaving the Ni-oxidation state unchanged. The second C-H bond is subsequently activated by the association of a bridged Ni-O2--Al. The oxidation state of the Ni atom is reduced from +3 to +1 during the formation of formaldehyde. Compared to Al2O3+/CH4 and YAlO3+/CH4 systems, the Ni-atom substitution increases the overall reaction rate by roughly an order of magnitude and yields a CH3•/CH2O branching ratio of 0.62/0.38. The present study provides molecular-level insights into the highly efficient gas-phase reaction mechanism contributing to an improved understanding of methane conversion by Ni/Al2O3 catalysts.

A viral movement protein co-opts endoplasmic reticulum luminal-binding protein and calreticulin to promote intracellular movement.

Intracellular movement is an important step for the initial spread of virus in plants during infection. This process requires virus-encoded movement proteins (MPs) and their interaction with host factors. Despite the large number of known host factors involved in the movement of different viruses, little is known about host proteins that interact with one of the MPs encoded by potexviruses, the triple-gene-block protein 3 (TGBp3). The main obstacle lies in the relatively low expression level of potexviral TGBp3 in hosts and the weak or transient nature of interactions. Here, we used TurboID-based proximity labeling to identify the network of proteins directly or indirectly interacting with the TGBp3 of a potexvirus, Bamboo mosaic virus (BaMV). Endoplasmic reticulum (ER) luminal-binding protein 4 and calreticulin 3 of Nicotiana benthamiana (NbBiP4 and NbCRT3, respectively) associated with the functional TGBp3-containing BaMV movement complexes, but not the movement-defective mutant, TGBp3M. Fluorescent microscopy revealed that TGBp3 colocalizes with NbBiP4 or NbCRT3 and the complexes move together along ER networks to cell periphery in N. benthamiana. Loss- and gain-of-function experiments revealed that NbBiP4 or NbCRT3 is required for the efficient spread and accumulation of BaMV in infected leaves. In addition, overexpression of NbBiP4 or NbCRT3 enhanced the targeting of BaMV TGBp1 to plasmodesmata (PD), indicating that NbBiP4 and NbCRT3 interact with TGBp3 to promote the intracellular transport of virion cargo to PD that facilitates virus cell-to-cell movement. Our findings revealed additional roles for NbBiP4 and NbCRT3 in BaMV intracellular movement through ER networks or ER-derived vesicles to PD, which enhances the spread of BaMV in N. benthamiana.

Colorectal cancer organoid models uncover oxaliplatin-resistant mechanisms at single cell resolution.

PURPOSE: Oxaliplatin-based chemotherapy is a standard treatment for advanced colorectal cancer (CRC) patients. However, chemoresistance-induced resistance is an essential cause for mortality. Therefore, it is necessary to study the mechanism of drug resistance in CRC. METHODS: Here, we established two strains of patient-derived organoids (PDOs) selected from oxaliplatin-resistant and treatment-naïve CRC patients. To dissect the drug-resistant mechanisms, these CRC-PDOs were subjected to single-cell RNA sequencing (scRNA-Seq). RESULTS: We found that the drug sensitivity test outcome from these organoids subjected to oxaliplatin and 5-FU exposure was consistent with the clinic readout. CRC-PDOs well recapitulated the morphology and histology of their parental biopsies based on HE and IHC staining of pathological biomarkers. The scRNA-Seq data filtered drug-resistant cell populations and related signaling pathways (e.g. oxidative phosphorylation and ATP metabolic process). The data also revealed several putative drug resistant-driven genes (STMN1, VEGFA and NDRG1) and transcription factors (E2F1, BRCA1, MYBL2, CDX2 and CDX1). CONCLUSION: We generated an oxaliplatin-resistant CRC organoid model that was employed to provide potential therapeutic targets for treating CRC patients exhibiting oxaliplatin-resistance.

In vivo comparison of the degradation and osteointegration properties of micro-arc oxidation-coated Mg-Sr and Mg-Ca alloy scaffolds.

BACKGROUND: Magnesium (Mg) alloy have biodegradation and mechanical properties that are similar to those of human bone, making it a promising candidate material for inclusion in implantable medical devices. OBJECTIVE: The osteointegration effect of Mg alloy scaffolds with different corrosion rates were studied and evaluated in large bone defect models. METHOD: Mg-Sr and Mg-Ca alloy scaffolds with a 20-µm Micro-arc oxidation (MAO) coating were used to repair critical bone defects for subsequent assessment of each alloy's degradation and osteointegration by X-ray, Micro-CT, fluorescence and histological examination. RESULTS: At 12 weeks post-implantation, each defect was found to be effectively reconstructed by either of the Mg alloys based on X-ray and Micro-CT images. The corrosion rate (CR) of each Mg alloy - as calculated based on micro-computed tomography information - demonstrated that the MAO coating could provide effective protection for only 4 weeks post-surgery. From weeks 8 to 12, the CR of the Mg-Ca alloy scaffold increased from 1.34 ± 0.23 mm/y to 1.57 ± 0.16 mm/y. In contrast, the CR of the Mg-Sr alloy scaffold decreased from 0.58 ± 0.14 mm/y to 0.54 ± 0.16 mm/y. However, fluorescence and histological examination revealed more mature, closely and regularly arranged newborn osteocytes at the Mg-Ca scaffold-fracture interface e from weeks 8 to 12 after surgery. CONCLUSION: The Mg-Sr scaffold was more corrosion resistant and the Mg-Ca scaffold yielded a better overall repair, which indicates that the CR of magnesium alloys matches the rate of new bone formation and is the key to repair bone defects as a bone substitute.

NbPsbO1 Interacts Specifically with the Bamboo Mosaic Virus (BaMV) Subgenomic RNA (sgRNA) Promoter and Is Required for Efficient BaMV sgRNA Transcription.

Many positive-strand (+) RNA viruses produce subgenomic RNAs (sgRNAs) in the infection cycle through the combined activities of viral replicase and host proteins. However, knowledge about host proteins involved in direct sgRNA promoter recognition is limited. Here, in the partially purified replicase complexes from Bamboo mosaic virus (BaMV)-infected tissue, we have identified the Nicotiana benthamiana photosystem II oxygen-evolving complex protein, NbPsbO1, which specifically interacted with the promoter of sgRNA but not that of genomic RNA (gRNA). Silencing of NbPsbO1 expression suppressed BaMV accumulation in N. benthamiana protoplasts without affecting viral gRNA replication. Overexpression of wild-type NbPsbO1 stimulated BaMV sgRNA accumulation. Fluorescent microscopy examination revealed that the fluorescence associated with NbPsbO1 was redistributed from chloroplast granal thylakoids to stroma in BaMV-infected cells. Overexpression of a mislocalized mutant of NbPsbO1, dTPPsbO1-T7, inhibited BaMV RNA accumulation in N. benthamiana, whereas overexpression of an NbPsbO1 derivative, sPsbO1-T7, designed to be targeted to chloroplast stroma, upregulated the sgRNA level. Furthermore, depletion of NbPsbO1 in BaMV RdRp preparation significantly inhibited sgRNA synthesis in vitro but exerted no effect on (+) or (-) gRNA synthesis, which indicates that NbPsbO1 is required for efficient sgRNA synthesis. These results reveal a novel role for NbPsbO1 in the selective enhancement of BaMV sgRNA transcription, most likely via direct interaction with the sgRNA promoter. IMPORTANCE Production of subgenomic RNAs (sgRNAs) for efficient translation of downstream viral proteins is one of the major strategies adapted for viruses that contain a multicistronic RNA genome. Both viral genomic RNA (gRNA) replication and sgRNA transcription rely on the combined activities of viral replicase and host proteins, which recognize promoter regions for the initiation of RNA synthesis. However, compared to the cis-acting elements involved in the regulation of sgRNA synthesis, the host factors involved in sgRNA promoter recognition mostly remain to be elucidated. Here, we found a chloroplast protein, NbPsbO1, which specifically interacts with Bamboo mosaic virus (BaMV) sgRNA promoter. We showed that NbPsbO1 is relocated to the BaMV replication site in BaMV-infected cells and demonstrated that NbPsbO1 is required for efficient BaMV sgRNA transcription but exerts no effect on gRNA replication. This study provides a new insight into the regulating mechanism of viral gRNA and sgRNA synthesis.

Concordance between treatment recommendations provided by IBM Watson for Oncology and a multidisciplinary tumor board for breast cancer in China.

OBJECTIVE: Watson for Oncology (WFO), an artificial intelligence from IBM Corporation, can provide a treatment plan by analyzing patient's disease characteristics. The present study was performed to examine the concordance between treatment recommendations proposed by WFO and the multidisciplinary tumor board at our center. The aim was to explore the feasibility of using WFO for breast cancer cases in China and to ascertain the ways to make WFO more suitable for Chinese patients with breast cancer. METHODS: Data from 302 breast cancer patients treated at the Second Affiliated Hospital of Xi'an Jiaotong University between October 2016 and February 2018 was retrieved and retrospectively analyzed by WFO. The recommendations were divided into 'recommended', 'considered' and 'not recommended' groups. Results were considered concordant when oncologists' recommendations were categorized as 'recommended' or 'for consideration' by WFO. RESULTS: The concordance rate of 200 subjects with postoperative adjuvant therapy was 77%. However, the rate was 27.5% in the remaining 102 cases with metastatic disease receiving either first-line or no treatment. Further analysis demonstrated that inconsistencies were mainly due to different choices of chemotherapy regimens. Subgroup study indicates that tumor stage, receptor status and age also had influences at the concordance rate. CONCLUSION: The results of this study suggest that WFO is a promising artificial intelligence system for the treatment of breast cancer. These findings can also serve as a reference framework for the inclusion of artificial intelligence in the ongoing medical reform in China.

Prognostic factors of EGFR-mutated metastatic adenocarcinoma of lung.

PURPOSE: The first-line treatment of metastatic lung adenocarcinoma with epidermal growth factor receptor (EGFR) mutation is tyrosine kinase inhibitor (TKI). This study aimed to evaluate potential factors affecting the progression-free survival under TKI treatment. METHODS: Forty one patients with EGFR-mutated metastatic lung adenocarcinoma under first-line TKI treatment were retrospectively evaluated. Ten factors potentially influencing the progression-free survival were studied: patients' age, gender, smoking history, number of comorbidities, performance status, tumor mutation site, maximum of standardized uptake value (SUVmax) of primary tumor in FDG PET/CT, serum CEA level, number of metastatic organs and presence of pleural/pericardial effusion. Mantel-Cox tests and waterfall plots were performed for statistical analyses. RESULTS: Statistical evaluation demonstrated that primary SUVmax, serum CEA level, gender and smoking history were important prognostic factors, with corresponding p values of 0.001, 0.023, 0.034 and 0.041 respectively in Mantel-Cox analyses. CONCLUSION: Low primary SUVmax, low serum CEA level, female and never smoker were four prognostic factors suggestive of good response to TKI in mutated EGFR metastatic lung adenocarcinoma. SUVmax is probably the most important among the four factors.

Monocarboxylate Transporter 4 (MCT4) Overexpression Is Correlated with Poor Prognosis of Osteosarcoma.

BACKGROUND Monocarboxylate transporter 4 (MCT4) is a critical element for glycolytic metabolism and malignant behaviors in many tumor cells. This study aimed to determine the expression level of MCT4 protein and its prognostic value in osteosarcoma. MATERIAL AND METHODS MCT4 expression was detected via immunohistochemical and Western blot analysis for 100 osteosarcoma patients. The correlation between MCT4 expression and clinical factors among the patients was analyzed using the chi-square test. Overall survival of osteosarcoma patients was estimated by Kaplan-Meier analysis. The prognostic value of MCT4 was evaluated using Cox regression analysis with adjustments for clinicopathological variables. RESULTS MCT4 expression was significantly upregulated in osteosarcoma tissues compared with that in adjacent normal ones, detected via both immunohistochemical and Western blot analyses. High MCT4 expression showed a positive association with distant metastasis (P=0.000) and recurrence (P=0.000) of osteosarcoma. Kaplan-Meier analysis indicated that overall survival of osteosarcoma patients was significantly higher in the low MCT4 expression group than in the high expression group (log-rank test, P<0.001). Multivariate analysis indicated that MCT4 expression and clinical stage, which are tightly related to the prognosis of osteosarcoma, might be independent predictors of osteosarcoma prognosis. CONCLUSIONS High MCT4 expression appears to contribute to osteosarcoma progression and the upregulation of MCT4 may predict poor prognosis among osteosarcoma patients.

[In vivo study of a novel micro-arc oxidation coated magnesium-zinc-calcium alloy scaffold/autologous bone particles repairing critical size bone defect in rabbit].

Objective: To evaluate the effect of a novel micro-arc oxidation (MAO) coated magnesium-zinc-calcium (Mg-Zn-Ca) alloy scaffold/autologous bone particles to repair critical size bone defect (CSD) in rabbit and explore the novel scaffold in vivo corrosion resistance and biocompatibility. Methods: Seventy-two New Zealand white rabbits were randomly divided into 3 groups ( n=24), group A was uncoated Mg-Zn-Ca alloy scaffold group, group B was 10 µm MAO coated Mg-Zn-Ca alloy scaffold group, and group C was control group with only autologous bone graft. The animals were operated to obtain bilateral ulnar CSD (15 mm in length) models. The bone fragment was removed and minced into small particles and were filled into the scaffolds of groups A and B. Then, the scaffolds or autologous bone particles were replanted into the defects. The animals were sacrificed at 2, 4, 8, and 12 weeks after surgery (6 rabbits each group). The local subcutaneous pneumatosis was observed and recorded. The ulna defect healing was evaluated by X-ray image and Van Gieson staining. The X-ray images were assessed and scored by Lane-Sandhu criteria. The percentage of the lost volume of the scaffold (ΔV) and corrosion rate (CR) were calculated by the Micro-CT. The Mg 2+ and Ca 2+ concentrations were monitored during experiment and the rabbit liver, brain, kidney, and spleen were obtained to process HE staining at 12 weeks after surgery. Results: The local subcutaneous pneumatosis in group B was less than that in group A at 2, 4, and 8 weeks after surgery, showing significant differences between 2 groups at 2 and 4 weeks after surgery ( P<0.05); and the local subcutaneous pneumatosis was significantly higher in group B than that in group A at 12 weeks after surgery ( P<0.05). The X-ray result showed that the score of group C was significantly higher than those of groups A and B at 4 and 8 weeks after surgery ( P<0.05), and the score of group B was significantly higher than that of group A at 8 weeks ( P<0.05). At 12 weeks after surgery, the scores of groups B and C were significantly higher than that of group A ( P<0.05). Meanwhile, the renew bone moulding of group B was better than that in group A at 12 weeks after surgery. Micro-CT showed that ΔV and CR in group B were significantly lower than those in group A ( P<0.05). Van Gieson staining showed that group B had better biocompatibility and osteanagenesis than group A. The Mg 2+ and Ca 2+ concentrations in serum showed no significant difference between groups during experiments ( P>0.05). And there was no obvious pathological changes in the liver, brain, kidney, and spleen of the 3 groups with HE staining at 12 weeks. Conclusion: The MAO coated Mg-Zn-Ca alloy scaffold/autologous bone particles could be used to repair CSD effectively. At the same time, 10 µm MAO coating can effectively improve the osteanagenesis, corrosion resistance, and biocompatibility of Mg-Zn-Ca alloy scaffold.

[Elimination of Entercoccus faecalis with different disinfection methods in root canals in vitro].

PURPOSE: To compare the elimination effect against E.faecalis in root canals with different methods. METHODS: Fifty extracted premolars with single root canal were selected. After cleaning and autoclaving, they were contaminated by E.faecalis and incubated for 28 days as models. Then the models were randomly and equally divided into 5 groups and treated as below: specimens in group A were treated with saline irrigation, specimens in group B were treated with 3% NaClO irrigation (as positive control), specimens in group C were treated with PUI, specimens in group D were treated with diode laser radiation, specimens in group E were treated with combination of PUI and diode laser radiation. The specimens from root canals were collected by paper points. The bacterial suspensions were later serially diluted and plated on tryptic soy agar plates to enumerate the CFUs after 48 hours. Statistical analysis was performed using SAS 8.02 software package. RESULTS: As with all parts of the root canal in aggregate, the CFUs of the specimens treated with PUI, diode laser radiation and the combination of them were significantly lower than the specimens treated with saline irrigation (P<0.01), but there was no significant difference among 3 groups (P>0.05). However, the specimens treated with 3% NaClO irrigation had the best effect of disinfection. The number of CFUs in the specimens treated with 3% NaClO was almost zero. There was no significant difference between this group and others in CFUs(P<0.01). CONCLUSIONS: Specimens treated with PUI, diode laser radiation and the combination of them showed great effect of elimination against biofilm of Enterococcus faecalis compared with saline irrigation. Irrigation with 3% NaClO was the most efficient method in this experiment.

The clinical value of dynamic contrast-enhanced MRI in differential diagnosis of malignant and benign ovarian lesions.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is widely used in preoperative diagnosis of various tumors. We investigated the clinical value of DCE-MRI in differential diagnosis of malignant and benign ovarian lesions. The study involved 48 subjects with surgical pathology-confirmed ovarian tumors with solid components. Early dynamic phase enhancement performances of the ovarian lesions in patients were assessed, including the enhancement pattern, time-signal intensity curve (TIC), signal intensity rate at the initial 60 s (SI60), time to peak within 200 s (TTP200), and slope ratio. There were significant differences in enhancement patterns between benign and malignant ovarian tumors (P < .05). A total of 30 malignant tumors (30/31) displayed type I TIC, 8 benign tumors (8/13) showed type III TIC, and significant differences were found in TIC type between malignant and benign ovarian lesions (P < 0.01). Benign ovarian tumors showed lower SI60 (%) and slope ratio, as well as significantly prolonged TTP20, compared to malignant ovarian tumors (all P < 0.01). The microvessel count (MVC) of malignant tumors was significantly higher than that of benign tumors (P < 0.05). Receiver operating characteristic (ROC) curve analyses revealed that DCE-MRI provided an optimal diagnostic performance with threshold values of SI60 at 83.40 %, TTP200 at 77.65 s, and slope ratio at 4.12. These findings revealed that DCE-MRI provides critical information required for differential diagnosis of malignant and benign ovarian lesions.

Rapid analysis of phthalates in beverage and alcoholic samples by multi-walled carbon nanotubes/silica reinforced hollow fibre-solid phase microextraction.

A novel procedure based on multi-walled carbon nanotubes (MWCNTs)/silica reinforced hollow fibre solid-phase microextraction combined with gas chromatography-mass spectrometry has been developed to analyse trace phthalate acid esters in beverage and alcoholic samples. Because of their excellent adsorption capability towards hydrophobic compounds, functionalized MWCNTs, acting as solid-phase sorbent, were co-deposited with silica particles in the pores of polypropylene hollow fibre through a layer-by-layer self-assembly technique. The parameters influencing the extraction efficiency, such as pH values and ionic strength of sample solution, extraction time, temperature and desorption solvent were optimised. Recoveries for phthalates at spiking levels in different matrices were satisfactory (between 68% and 115%). Moreover, the results were further confirmed by comparing them with those obtained using a solvent extraction method according to the national standard of China.