A fresh perspective on dissociation mechanism of cellulose in DMAc/LiCl system based on Li bond theory

In this case, various characterization technologies have been employed to probe dissociation mechanism of cellulose in N,N-dimethylacetamide/lithium chloride (DMAc/LiCl) system. These results indicate that coordination of DMAc ligands to the Li+-Cl- ion pair results in the formation of a series of Lix(DMAc)yClz (x = 1, 2; y = 1, 2, 3, 4; z = 1, 2) complexes. Analysis of interaction between DMAc ligand and Li center indicate that Li bond plays a major role for the formation of these Lix(DMAc)yClz complexes. And the saturation and directionality of Li bond in these Lix(DMAc)yClz complexes are found to be a tetrahedral structure. The hydrogen bonds between two cellulose chains could be broken at the nonreduced end of cellulose molecule via combined effects of basicity of Cl- ion and steric hindrance of [Li (DMAc)4]+ unit. The unique feature of Li bond in Lix(DMAc)yClz complexes is a key factor in determination of the dissociation mechanism.

[Establishment and efficiency test of a clinical prediction model of bronchopulmonary dysplasia associated pulmonary hypertension in very premature infants]

Objective: To develop a risk prediction model for identifying bronchopulmonary dysplasia (BPD) associated pulmonary hypertension (PH) in very premature infants. Methods: This was a retrospective cohort study. The clinical data of 626 very premature infants whose gestational age <32 weeks and who suffered from BPD were collected from October 1st, 2015 to December 31st, 2021 of the Seventh Medical Center of the People's Liberation Army General Hospital as a modeling set. The clinical data of 229 very premature infants with BPD of Hunan Children's Hospital from January 1 st, 2020 to December 31st, 2021 were collected as a validation set for external verification. The very premature infants with BPD were divided into PH group and non PH group based on the echocardiogram after 36 weeks' corrected age in the modeling set and validation set, respectively. Univariate analysis was used to compare the basic clinical characteristics between groups, and collinearity exclusion was carried out between variables. The risk factors of BPD associated PH were further screened out by multivariate Logistic regression, and the risk assessment model was established based on these variables. The receiver operating characteristic (ROC) area under curve (AUC) and Hosmer-Lemeshow goodness-of-fit test were used to evaluate the model's discrimination and calibration power, respectively. And the calibration curve was used to evaluate the accuracy of the model and draw the nomogram. The bootstrap repeated sampling method was used for internal verification. Finally, decision curve analysis (DCA) to evaluate the clinical practicability of the model was used. Results: A total of 626 very premature infants with BPD were included for modeling set, including 85 very premature infants in the PH group and 541 very premature infants in the non PH group. A total of 229 very premature infants with BPD were included for validation set, including 24 very premature infants in the PH group and 205 very premature infants in the non PH group. Univariate analysis of the modeling set found that 22 variables, such as artificial conception, fetal distress, gestational age, birth weight, small for gestational age, 1 minute Apgar score ≤7, antenatal corticosteroids, placental abruption, oligohydramnios, multiple pulmonary surfactant, neonatal respiratory distress syndrome (NRDS)>stage Ⅱ, early pulmonary hypertension, moderate-severe BPD, and hemodynamically significant patent ductus arteriosus (hsPDA) all had statistically significant influence between the PH group and the non PH group (all P<0.05). Antenatal corticosteroids, fetal distress, NRDS >stage Ⅱ, hsPDA, pneumonia and days of invasive mechanical ventilation were identified as predictive variables and finally included to establish the Logistic regression model. The AUC of this model was 0.86 (95%CI 0.82-0.90), the cut-off value was 0.17, the sensitivity was 0.77, and the specificity was 0.84. Hosmer-Lemeshow goodness-of-fit test showed that P>0.05. The AUC for external validation was 0.88, and the Hosmer-Lemeshow goodness-of-fit test suggested P>0.05. Conclusions: A high sensitivity and specificity risk prediction model of PBD associated PH in very premature infants was established. This predictive model is useful for early clinical identification of infants at high risk of BPD associated PH.

The "5Ts" screening tool: Enhancements and threshold values for effective TMD identification

OBJECTIVE

This study aimed to enhance the quintessential "five temporomandibular disorder (TMD) symptoms" (5Ts) screener by incorporating frequency options and distinguishing between TMJ and muscle pain. The diagnostic accuracy along with cut-off points for the effective identification of TMDs was also established.

METHODS

Participants, aged ≥18 years, were recruited from a university-based hospital. After completing surveys encompassing demographic data and the enhanced 5Ts (with frequency options [5Ts-F] and differentiation of TMJ/muscle pain [6Ts-F]), protocolized interviews and clinical examinations were performed following DC/TMD. The diagnostic accuracy and best cut-off points were determined with the area under the receiver operating characteristic curves (AUCs).

RESULTS

324 participants were recruited (mean age 30.0 ± 11.4 years). Among these, 86.4% had TMDs. 5Ts exhibited high diagnostic accuracy for detecting all TMDs (AUC = 0.92) with sensitivity/specificity values of 83.9%/88.6%. Both 5Ts-F and 6Ts-F had slightly better accuracy (AUCs = 0.95/0.96), comparable sensitivity, and superior specificity (97.7%) compared to 5Ts. The best cut-off points were 1.5 for 5Ts and 2.5 for 5Ts-F/6Ts-F.

CONCLUSIONS

Although all three TMD screeners presented high diagnostic accuracy, 5Ts-F/6Ts-F had notably improved specificity. 5Ts scores of >1.5 and 5Ts-F/6Ts-F scores of >2.5 are to be applied for screening the presence of TMDs.

Preparation of Cellulose Nanofibers from Corn Stalks by Fenton Reaction: A New Insight into the Mechanism by an Experimental and Theoretical Study

Agricultural biomass wastes are an abundant feedstock for biorefineries. However, most of these wastes are not treated in the right way. Here, corn stalks (CSs) were assigned as the raw material to produce cellulose nanofibers (CNFs) via in situ Fenton oxidation treatment. In order to probe the formation mechanism of an in situ Fenton reactor, the bonding interaction of hydrated Fe²⁺ ions and fiber has been systemically studied based on adsorption experiments, IR spectroscopy, density functional theory (DFT) calculations, and Raman spectroscopy. The results indicate that the coordination of the hydrated Fe²⁺ ion to the fiber generates a quasi-octahedral-coordinated sphere around the Fe center. The Jahn-Teller distortion effect of the Fe center promotes the Fe-O₂H₂ bonding interaction via reduction of the energy gap of the d_z² orbital of the Fe center and π_2py/π_2pz orbitals of the H₂O₂ molecule. The oxidation treatment of the pretreated CS by the in situ Fenton process shows the formation of a new carboxyl group on the fiber surface. The scanning electron microscopy image shows that the Fenton-treated fiber was scattered into the nanosized CNFs with a diameter of up to 50 nm. Both experimental and theoretical studies show that the pseudo-first-order kinetic reaction could describe the in situ Fenton kinetics well. Moreover, the proposed catalytic cycle shows that the large thermodynamic barrier is the cleavage of the O-O bond of H₂O₂ to generate the ^•OH radical, and the whole catalytic cycle is found to be spontaneous at room temperature.

A Systematic Theoretical Study on Electronic Interaction in Cu-based Single-Atom Alloys

A meticulous understanding of the electronic structure of catalysts may provide new insight into catalytic performances. Here, we present a d-d interaction model to systematically study the electronic interaction in Cu-based single-atom alloys. We refine three types of electronic interactions according to the position of the antibonding state relative to the Fermi level. Moreover, we also find a special phenomenon in Mn-doped single-atom alloys in which no obvious electronic interaction is found, and the doped Mn metal seems to be a free atom. Then, taking Hf/Mn-doped single-atom alloys as an example, we discuss the electronic structure based on the density of states, charge transfer, crystal orbital Hamilton population, and wavefunctions. To support the proposed model and help analyze the data, we perform an energetic analysis of water dissociation in the water-gas shift reaction. The calculation results well confirm the d-d interaction model, where alloys with the position of the antibonding state close to the Fermi level exhibit excellent water dissociation ability in the water-gas shift reaction. However, the catalytic performance of the Mn-doped alloy is unsatisfactory, which is caused by its own special phenomenon.

[The influence of sacroiliac joint reduction quality on the clinical effect of bionic reduction and internal fixation for pelvic ring injury]

Objective: To examine the influence of sacroiliac joint reduction quality on the clinical effect of bionic reduction and internal fixation for pelvic ring injury. Methods: From January 2014 to February 2019,the clinical data of 78 patients diagnosed with pelvic ring injury involving sacroiliac joints and treated with bionic reduction and internal fixation at Honghui Hospital Affiliated to Medical College of Xi'an Jiaotong University were retrospectively analyzed.There were 48 males and 30 females,aged (48.3±8.3)years (range:28 to 68 years).After bionic reduction and internal fixation,the patients were grouped according to the maximum displacement distance (d) of sacroiliac joint residual on the damaged side measured by CT examination. Patients with d≤5 mm were included in anatomical bionic reduction group,and patients with d>5 mm were included in non-anatomical bionic reduction group.In non-anatomical bionic reduction group,according to the direction of residual displacement,the patients were divided into separation displacement group and anterior-posterior displacement group. The X-ray examination was performed immediately and at the last follow-up after operation.If sacroiliac joint was relocated,or internal plant loosening,displacement,fracture and re-displacement of fracture,it was defined as internal fixation failure.Majeed pelvic fracture scoring system was used to evaluate the postoperative functional status of the two groups,and visual analogue scale (VAS) was used to evaluate the postoperative pain.Comparison between groups was performed by completely random design ANOVA,χ² test,Fisher's exact test,Mann-Whitney U and Kruskal-Wallis H test. Results: According to the CT examination,28 cases were included in anatomical bionic reduction group,and 50 cases were included in non-anatomical bionic reduction group.In non-anatomical bionic reduction group,27 cases were divided into separation displacement group and 23 cases were in anterior-posterior displacement group.There was no significant difference in general data among anatomical bionic reduction group,separation displacement group and anterior-posterior displacement group (P>0.05). The follow-up time was (37.8±6.6) months (range:25 to 51 months). At the last follow up,the excellent and good rate of Majeed score in anatomical bionic reduction group was 96.4%(27/28),which was better than that in separation displacement group(74.1%(20/27)) and anterior-posterior displacement group (30.4%(7/23)),the difference was statistically significant (Z=-6.479,P<0.01;Z=-6.256,P<0.01); and the good rate of the separation displacement group was better than that of the anterior-posterior displacement group(Z=-3.607,P<0.01).The VAS of anatomical bionic reduction group (17 cases with 0 point, 11 cases with 1 to 3 points) were lower than that of the displacement group (6 cases with 0 point,16 cases with 1 to 3 points,5 cases with 4 to 6 points) and anterior-posterior displacement group (3 cases with 0 point,7 cases with 1 to 3 points,13 cases with 4 to 6 points),the difference was statistically significant (Z=-3.515,P<0.01;Z=-3.506,P<0.01),and there was no difference between separation displacement group and anterior-posterior displacement group.Total of 8 cases of internal fixation failure occurred,and the failure rate of anatomical bionic reduction group (0,0/28) was lower than that of the separation displacement group (11.1%,3/27) and anterior-posterior displacement group (21.7%,5/23) (P=0.111,P=0.014),and there was no difference between separation displacement group and anterior-posterior displacement group(P=0.444). Conclusions: In the bionic reduction and internal fixation of pelvic fracture involving sacroiliac joint injury,the functional status,pain and internal fixation failure rate of patients with anatomical bionic reduction of sacroiliac joint are significantly better than those in the non-anatomical bionic reduction.The functional recovery of patients with separation displacement is better than that of the patients with anterior and posterior displacement.

Rhizobacteria communities reshaped by red mud based passivators is vital for reducing soil Cd accumulation in edible amaranth

Red mud (RM) was constantly reported to immobilize soil cadmium (Cd) and reduce Cd uptake by crops, but few studies investigated whether and how RM influenced rhizobacteria communities, which was a vital factor determining Cd bioavailability and plant growth. To address this concern, high-throughput sequencing and bioinformatics were used to analyze microbiological mechanisms underlying RM application reducing Cd accumulation in edible amaranth. Based on multiple statistical models (Detrended correspondence analysis, Bray-Curtis, weighted UniFrac, and Phylogenetic tree), this study found that RM reduced Cd content in plants not only through increasing rhizosphere soil pH, but by reshaping rhizobacteria communities. Special taxa (Alphaproteobacteria, Gammaproteobacteria, Actinobacteriota, and Gemmatimonadota) associated with growth promotion, anti-disease ability, and Cd resistance of plants preferentially colonized in the rhizosphere. Moreover, RM distinctly facilitated soil microbes' proliferation and microbial biofilm formation by up-regulating intracellular organic metabolism pathways and down-regulating cell motility metabolic pathways, and these microbial metabolites/microbial biofilm (e.g., organic acid, carbohydrates, proteins, S^2-, and PO₄^3-) and microbial cells immobilized rhizosphere soil Cd via the biosorption and chemical chelation. This study revealed an important role of reshaped rhizobacteria communities acting in reducing Cd content in plants after RM application.

[Multicenter real world study on the efficacy and safety of eribulin for the treatment of advanced breast cancer]

Objective: To explore the efficacy and safety of real-world eribulin in the treatment of metastatic breast cancer. Methods: From December 2019 to December 2020, patients with advanced breast cancer were selected from Beijing Chaoyang District Sanhuan Cancer Hospital, Shandong Cancer Hospital, Peking University Cancer Hospital, Baotou Cancer Hospital, Shengjing Hospital Affiliated to China Medical University, and Cancer Hospital of Chinese Academy of Medical Sciences. Kaplan-Meier method and Log rank test were used for survival analysis, and Cox regression model was used for multivariate analysis. Results: The median progression-free survival (PFS) of 77 patients was 5 months, the objective response rate (ORR) was 33.8%, and the disease control rate (DCR) was 71.4%. The ORR of patients with triple-negative breast cancer was 23.1%, and the DCR was 57.7%; the ORR of patients with Luminal breast cancer was 40.0%, and the DCR was 77.8%; the ORR of patients with HER-2 overexpression breast cancer was 33.3%, and the DCR was 83.3%. ORR of 50.0% and DCR of 66.7% for patients treated with eribulin as first to second line treatment, ORR of 29.4% and DCR of 76.5% for patients treated with third to fourth line and ORR of 28.6% and DCR of 71.4% for patients treated with five to eleven line. The ORR of patients in the eribulin monotherapy group was 40.0% and the DCR was 66.0%; the ORR of patients in the combination chemotherapy or targeted therapy group was 22.2% and the DCR was 81.5%. Patients with a history of treatment with paclitaxel, docetaxel, or albumin paclitaxel during the adjuvant phase or after recurrent metastasis had an ORR of 32.9% and a DCR of 69.9% when treated with eribulin. The treatment efficacy is an independent prognostic factor affecting patient survival (P<0.001). The main adverse reactions in the whole group of patients were Grade Ⅲ-Ⅳ neutrophil decline [29.9% (23/77)], and other adverse reactions were Grade Ⅲ-Ⅳ fatigue [5.2% (4/77)], Grade Ⅲ-Ⅳ peripheral nerve abnormality [2.6% (2/77)] and Grade Ⅲ-Ⅳ alopecia [2.6% (2/77)]. Conclusions: Eribulin still has good antitumor activity against various molecular subtypes of breast cancer and advanced breast cancer that has failed multiple lines of chemotherapy, and the adverse effects can be controlled, so it has a good clinical application value.

Reduction of N2 to NH3 catalyzed by a Keggin-type polyoxometalate-supported dual-atom catalyst

In the present paper, a polyoxometalate-supported dual-atom catalyst has been designed for the nitrogen reduction reaction based on our density functional theory calculations.

Electroreduction of N2 to NH3 catalyzed by a Mn/Re(111) single-atom alloy catalyst with high activity and selectivity: a new insight from a first-principles study

Periodic density functional theory calculations show that a Mn/Re(111) single-atom alloy may be an excellent catalyst with high activity and selectivity for the electrocatalytic N2 reduction reaction.

[Consistency of peripheral whole blood and venous serum procalcitonin in children: a multicenter parallel controlled study]

Objective: To explore the consistency of peripheral whole blood and venous serum procalcitonin (PCT) levels, and the value of peripheral whole blood PCT in evaluating pediatric bacterial infection. Methods: This multicenter cross-sectional parallel control study was conducted in 11 children's hospital. All the 1 898 patients older than 28 days admitted to these hospitals from March 2018 to February 2019 had their peripheral whole blood and venous serum PCT detected simultaneously with unified equipment, reagent and method. According to the venous serum PCT level, the patients were stratified to subgroups. Analysis of variance and chi-square test were used to compare the demographic characteristics among groups. And the correlation between the peripheral blood and venous serum PCT level was investigated by quantitative Pearson correlation analysis.The PCT resultes were also converted into ranked data to further test the consistency between the two sampling methods by Spearman's rank correlation test. Furthermore, the ranked data were converted into binary data to evaluate the consistency and investigate the best cut-off of peripheral blood PCT level in predicting bacterial infection. Results: A total of 1 898 valid samples were included (1 098 males, 800 females),age 27.4(12.2,56.7) months. There was a good correlation between PCT values of peripheral whole blood and venous serum (r=0.97, P<0.01). The linear regression equation was PCT_{venous serum}=0.135+0.929×PCT_{peripheral whole blood}. However, when stratified to 5 levels, PCT results showed diverse and unsatisfied consistency between the two sampling methods (r=0.51-0.92, all P<0.01). But after PCT was converted to ordinal categorical variables, the stratified analysis showed that the coincidence rate of the measured values by the two sampling methods in each boundary area was 84.9%-97.1%. The dichotomous variables also showed a good consistency (coincidence rate 96.8%-99.3%, Youden index 0.82-0.89). According to the severity of disease, the serum PCT value was classified into 4 intervals（<0.5、0.5-<2.0、2.0-<10.0、≥10.0 μg/L）, and the peripheral blood PCT value also showed a good predictive value (AUC value was 0.991 2-0.997 9). The optimal cut points of peripheral whole blood PCT value 0.5、1.0、2.0、10.0 μg/L corresponding to venous serum PCT values were 0.395, 0.595, 1.175 and 3.545 μg/L, respectively. Conclusions: There is a good correlation between peripheral whole blood PCT value and the venous serum PCT value, which means that the peripheral whole blood PCT could facilitate the identification of infection and clinical severity. Besides, the sampling of peripheral whole blood is simple and easy to repeat.

[Study on Cep63 expression and apoptosis of thyroid papillary carcinoma cell lines TPC-1]

Objective: To investigate the effect of centrosomal protein Cep63 on the apoptosis of papillary thyroid carcinoma (PTC) cell lines TPC-1 and underlying mechanism. Methods: With collected PTC tissues and adjacent tissues, Cep63 expression was detected by RT-qPCR and its relationship with clinicopathological factors was analyzed. The experiment included negative control group (NC), low expression group (Cep63(-)) and overexpression group (Cep63(+)), and wild-type TPC-1 cells were transfected with Cep63 lentivirus. The efficiency of Cep63 was detected by western blot (WB) and qRT-PCR. Cell proliferation ability was detected by plate cloning experiment and MTT assay. Cell apoptotic rate was detected by flow cytometry, and expression levels of apoptosis-related proteins were detected by immunohistochemistry and WB. The t-test was used to compare the differences in the means between the two groups, the one-way analysis of variance was used to compare multiple groups, and the chi-square test was used to analyze the association between gene expression levels and pathological factors. Results: Compared with NC group, cell proliferation ability was significantly decreased in Cep63(-) group (3.18±0.07 vs. 2.14±0.09, t=8.54, P<0.01) and significantly increased in Cep63(+) group (3.18±0.07 vs. 3.58±0.10, t=3.21, P<0.05). Apoptotic rates in NC, Cep63 (-) and Cep63 (+) groups were respectively 3.03%±0.24%, 8.66%±0.44% and 1.17%±0.44%, and the flow cytometry showed that the low expression of Cep63 significantly increased the apoptosis TPC-1 cells (F=157.7, P<0.001). Bcl-2 protein expression levels of NC, Cep63 (-) and Cep63 (+) groups were respectively 1.07±0.03, 0.49±0.01 and 1.99±0.09, and BAX protein expression levels of three groups were respectively 0.64±0.02, 1.06±0.01 and 0.21±0.03. WB showed that the expression level of Bcl-2 decreased (F=183.2, P<0.001), while the expression level of BAX was significantly up-regulated (F=283.7, P<0.001). Conclusion: Cep63 may regulate the apoptotic process of TPC-1 cells through Bcl-2/BAX pathway and Cep63 may be a potential oncogene of PTC.

[Expression of SQSTM1 in papillary thyroid carcinoma and its influence on invasion, migration and proliferation of papillary thyroid cancer cells]

Objective: To investigate the expression of SQSTM1 in thyroid papillary carcinoma and its influence on the invasion and migration of thyroid papillary carcinoma cells TPC-1. Methods: From April to June 2019, cancer tissues and adjacent tissues of 21 cases with thyroid papillary carcinoma in the First Affiliated Hospital of Zhengzhou University were collected, and the expression of SQSTM1 was detected by RT-qPCR. SQSTM1 knockdown cell line SQSTM1-KD-TPC-1 was constructed in TPC-1 cells by lentivirus transfection. RT-qPCR was used to detect SQSTM1 expression in TPC-1 cells and SQSTM1-KD-TPC-1 cells. The changes of invasion and migration before and after SQSTM1 knockdown in TPC-1 cells were detected by transwell test. The proliferation of TPC-1 and SQSTM1-KD-TPC-1 cells were detected by MTT and clone formation test. RT-qPCR was used to detect the gene expression of proliferation related proteins. Results: The expression of SQSTM1 in papillary thyroid carcinoma tissues was significantly higher than that in normal adjacent tissues, and 76.2%(16/21) of the petients showed high mRNA expression. Knock down SQSTM1 significantly inhibited the ability of tumor proliferation, invasion and migration, and the expression of proliferation-related proteins were significantly decreased (P<0.01), indicating that SQSTM1 was involved in the regulation of proliferation related pathway mechanism. Conclusion: SQSTM1 significantly promotes invasion, migration and proliferation in thyroid papillary cancer cells TPC-1 and may be a potential gene therapy target.

The use of main-group elements to mimic catalytic behavior of transition metals I: reduction of dinitrogen to ammonia catalyzed by bis(Lewis base)borylenium diradicals

The use of boron (B) atoms as transition metal mimics opens the door to new research in catalytic chemistry. An emerging class of compounds, bis(Lewis base)borylenes with an electron-rich B(i) center, are potential metal-free catalysts for dinitrogen bonding and reduction. Here, the molecular geometry, electronic structure, and possible reaction mechanism of a series of bis(Lewis base)borylene-dinitrogen compounds corresponding to the nitrogen reduction reaction have been investigated by using density functional theory (DFT) calculations. Our DFT calculations show that these free borylene compounds possess radical features and have the capability to activate N2 molecules via an effective combination of π(B → N2), π(N2 → B), and σ(N2 → B) electron transfer processes. The possible reaction mechanisms for direct conversion of N2 into NH3 for these bis(Lewis base)borylene-dinitrogen compounds have been systematically investigated along distal and alternating paths. The calculated free energy profiles indicate that the limiting potential of a bis(phosphine)borylene-dinitrogen compound is comparable to that of metal-based catalysts, which is the most promising candidate for the reduction of N2 to NH3via the alternating mechanism among all compounds studied here. The electronic structure analysis shows that the B center plays the role of an electron donor and acceptor alternatively in the consecutive six protonation and reduction processes, and thus acts as the electron transfer medium.

Degradation Mechanism of Benzo[a]pyrene Initiated by the OH Radical and 1O2: An Insight from Density Functional Theory Calculations

The degradation mechanism of benzo[a]pyrene (BaP) initiated by ^•OH and ¹O₂ in aqueous solution is investigated by density functional theory calculations. The main degradation products are BaP-1,6-quinone, BaP-3,6-quinone, BaP-4,6-quinone, and BaP-6,12-quinone. ^•OH and HO₂ are the main intermediate radical species. At a low initial concentration of ^•OH, ¹O₂ could be a primary driver for BaP degradation. The degradation mechanism includes six consecutive elementary reactions: (1) ¹O₂ initiation forming BaP-6-OO. (2) 1,3 H-shift (H atom shifts to the OO group) that is promoted by H₂O, forming BaP-6-OOH. (3) BaP-6-OOH decomposes into the ^•OH radical and BaP-6-O. (4) ^•OH addition to BaP-6-O forming BaP-6-O-1(3,4,12)-OH. (5) Extracting the H atom from the carbon with the OH group by ¹O₂. (6) Extracting the H atom from the OH group by HO₂. At a high initial concentration of ^•OH, the ^•OH-initiated and ¹O₂-initiated degradation reactions of BaP are both feasible. The degradation mechanism includes six consecutive elementary reactions: (1) ^•OH initiation forming BaP-6-OH or ¹O₂ initiation forming BaP-6-OO. (2) ¹O₂ addition to BaP-6-OH forming BaP-6-OH-12(1,3,4)-OO or ^•OH addition to BaP-6-OO forming BaP-6-OO-12(1,3,4)-OH. (3) Extracting the H atom from the carbon with the OH group by ¹O₂, forming HO₂. (4) 1,3 H-shift (H-shift from the carbon to the OO group), promoted by H₂O. (5) The loss of the OH radical. (6) Abstracting the H atom from the OH group by HO₂. In this paper, the formation of BaP-4,6-quinone via the BaP degradation is first reported. Water participates in the elementary reaction in which the H atom attached on the aromatic ring shifts to the OO group, serving as a bridge that stabilizes the transition state and transports the proton. A comprehensive investigation explains the degradation mechanism of BaP initiated by ^•OH and ¹O₂ in aqueous solution.

[Factors affecting the near-infrared autofluorescence intensity of parathyroid glands and intraoperative identification of parathyroid glands]

Objective: To evaluate the potential factors influencing the parathyroid autofluorescence intensity of near-infrared fluorescent (NIRF) and further value of NIRF in identifying the parathyroid during surgery. Methods: The clinical data of 51 patients who underwent thyroid or parathyroid surgery in the Department of Thyroid Surgery, the First Affiliated Hospital of Zhengzhou University from April to June 2019 were retrospectively analyzed, including 16 males and 35 females, aged 18 to 74 years.The fluorescence intensity (FI) of the parathyroid glands, thyroid glands and background, and the number of parathyroid glands detected by NIRF and white light were measured. Variance analysis, two independent samples t test and Spearman rank correlation analysis were used to analyze the relationship between standardized parathyroid FI and clinical variables. Chi square test was used to analyze the difference of parathyroid detection rate between NIRF and white light. Results: In the 51 patients, the mean standardized parathyroid FI was greater than the standardized thyroid FI (1.72 ± 0.68 vs. 1.25 ± 0.40, t=6.555, P<0.001). The standardized parathyroid FI was not associated with gender, age, operation type, BMI, preoperative serum Ca(2+), parathyroid hormone and calcitonin (all P>0.05), but it was associated with disease type (F=2.636, P<0.05). The mean standardized parathyroid FI of SHPT was lower than that of PTC, PTC with nodular goiter or NG(0.70±0.28 vs. 1.86±0.70, 1.69±0.49, 1.64±0.44, t value was 3.023, -1.129,-2.019, respectively, all P<0.05). There was no difference in the standardized parathyroid FI between SHPT and PHPT (1.34±0.18, t=1.218, P>0.05). There was no difference in standardized parathyroid FI between PHPT, PTC, NG, and PTC with NG(all P>0.05). Except for 3 cases of SHPT, 117 parathyroid glands were detected by NIRF and 101 parathyroid glands were detected by white light. The detection rate of parathyroid glands detected by NIRF was higher than that detected by white light (98.32% vs. 84.87%, χ(2)=13.974, P<0.001). In SHPT, the detection rate of parathyroid gland by NIRF was 25.00%. Conclusions: Except SHPT, parathyroid FI is not affected by other clinical variables. NIRF can improve the detection rate of parathyroid glands during operation.

Reduction of N2O by H2 Catalyzed by Keggin-Type Phosphotungstic Acid Supported Single-Atom Catalysts: An Insight from Density Functional Theory Calculations

In the present paper, the mechanisms of N₂O reduction by H₂ were systemically examined over various polyoxometalate-supported single-atom catalysts (SACs) M₁/PTA (M = Fe, Co, Mn, Ru, Rh, Os, Ir, and Pt; PTA = [PW₁₂O₄₀]^3-) by means of density functional theory calculations. Among these M₁/PTA SACs, Os₁/PTA SAC possesses high activity for N₂O reduction by H₂ with a relatively low rate-determining barrier. The favorable catalytic pathway involves the first and second N₂O decomposition over the Os₁/PTA SAC and hydrogenation of the key species after the second N₂O decomposition. Molecular geometry and electronic structure analyses along the favorable reaction pathway indicate that a strong charge-transfer cooperative effect of metal and support effectively improves the catalytic activity of Os₁/PTA SAC. The isolated Os atom not only plays the role of adsorption and activation of the N₂O molecule but also works as an electron transfer medium in the whole reaction process. Meanwhile, the PTA support with very high redox stability has also been proven to be capable of transporting the electron to promote the whole reaction. We expect that our computation results can provide ideas for designing new SACs for N₂O reduction by using H₂ selective catalytic reduction technology.

Emerging of canine kobuvirus in dogs in China, 2015

Canine kobuvirus (CaKoV) is a newly emerging virus in dogs, which relates to the diarrhea of dogs. To investigate the CaKoV infection in dog population, fecal samples of dogs were collected from three provinces of China in 2015. The results of genetic analysis based on the complete VP1 gene showed that six CaKoVs isolates in this study were closely related with the Chinese canine originated isolate CH1 (90.6%-91.9% nucleotide identities). The phylogenetic analysis demonstrated that the Chinese isolates clustered into a unique branch compared with isolates from other countries. The present study suggested that the CaKoVs had established infection in Chinese dog population. The systematic epidemiological investigation should be further carried out to evaluate the prevalence of the CaKoV infection in China.

Jahn-Teller Distorted Effects To Promote Nitrogen Reduction over Keggin-Type Phosphotungstic Acid Catalysts: Insight from Density Functional Theory Calculations

Molecular geometry, electronic structure, and possible reaction mechanism of a series of mono-transition-metal-substituted Keggin-type polyoxometalate (POM)-dinitrogen complexes [PW₁₁O₃₉M(N₂)] ^n- (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Tc, Ru, Rh, Pd, Ag, Cd, W, Re, Os, Ir, Pt, Au, and Hg) have been investigated by using density functional theory (DFT) calculations with M06L functional. The calculated adsorption energy of N₂ molecule, N-N bond length, N-N stretching frequency, and the NBO charge on the coordinated N₂ moiety indicate that Mo^II-, Tc^II-, W^II-, Re^II-, and Os^II-POM complexes are significant for binding and activation of the inert N₂ molecule. The degree of the N₂ activation can be classified into the "moderately activated" category according to Tuczek's sense [ J. Comput. Chem. 2006 , 27 , 1278 ]. Electronic structure and NBO analysis indicate that the terminal N atom of the coordinated N₂ molecule in these POM-dinitrogen complexes possesses more negative charge relative to the bridge N atom because Jahn-Teller distorted effects lead to an effective orbital mixture between σ_2s* orbital of N₂ and d _z² orbital of transition metal center. And the mono-lacunary Keggin-type POM ligand with five oxygen donor atoms serves as a strong electron donor to the bivalent metal center. Meanwhile, a catalytic cycle for direct conversion of N₂ into NH₃ has been systematically investigated based on a Re-POM complex along distal, alternating, and enzymatic pathways. The calculated free energy profile of the three catalytic cycles indicates that the distal mechanism is the favorable pathway in the presence of proton and electron donors.

CO oxidation over the polyoxometalate-supported single-atom catalysts M1/POM (Fe, Co, Mn, Ru, Rh, Os, Ir, and Pt; POM = [PW12O40]3–): a computational study on the activation of surface oxygen species

Density functional theory calculations have been carried out to explore the catalytic performance of a series of the M₁/POM (M = Fe, Co, Mn, Ru, Rh, Os, Ir, and Pt; POM = [PW₁₂O₄₀]³⁻) single-atom catalysts for CO oxidation.

Computational study on epoxidation of propylene by dioxygen using the silanol-functionalized polyoxometalate-supported osmium oxide catalyst

The silanol-functionalized POM-supported single-site Os oxide catalyst has been theoretically considered for epoxidation of propylene in the presence of dioxygen based on density functional theory calculations.

Calculations of NO reduction with CO over a Cu1/PMA single-atom catalyst: a study of surface oxygen species, active sites, and the reaction mechanism

Density functional theory calculations have been employed to probe the reaction mechanism of NO reduction with CO over a Cu₁/PMA (PMA is the phosphomolybdate, Cs₃PMo₁₂O₄₀) single-atom catalyst.

Activation mechanism of hydrogen peroxide by a divanadium-substituted polyoxometalate [γ-PV2W10O38(μ-OH)2]3-: A computational study

In the present paper, the reaction mechanism corresponding to activation of hydrogen peroxide (H₂O₂) by a divanadium-substituted polyoxometalate (POM) [γ-PV₂W₁₀O₃₈(μ-OH)₂]^3- (I) to form catalytic active species, peroxo complex [γ-PV₂W₁₀O₃₈(μ-η²,η²-O₂)]^3- (III), was studied by using the density functional theory (DFT) calculations method with B3LYP functional. The results indicate that coordination of H₂O₂ to I proceeds via a vanadium-center-assisted proton transfer pathway to remove the first water molecule and form a hydroperoxy intermediate [γ-PV₂W₁₀O₃₈(μ-OH) (μ-OOH)]^3- (II). And intermediate II occurs through three successive water-assisted proton transfer steps to remove the second water molecule and finally forms catalytic active species. The calculated overall energy profiles show that coordination of H₂O₂ to vanadium center requires a proton transfer barrier of about 24 kcal mol^-1. A detailed comparison of molecular geometries and electronic structure shows that the catalytic active species has a very interesting structural feature, where a superoxide radical (O₂^-) was embedded into two vanadium centers, and may be a potential nucleophile. The unique withdrawing electron properties and flexible bonding ability of the γ-Keggin-type POM ligand contribute to the formation of O₂^- radical. The tunable alternate arrangement of W-O bond series in γ-Keggin-type POM ligand contributes to the flexibility of the γ-Keggin-type POM ligand. Meanwhile, our DFT calculations show a good performance of B3LYP-gauge-independent atomic orbital (IGAIM) method for the calculation of ¹H NMR parameters of divanadium-substituted phosphotungstate.

[Effects of nasal polyps and allergy rhinitis on quantitative evaluation of subjective and objective assessment of chronic rhinosinusitis]

Objective:To investigate the effect of nasal polyps and allergy rhinitis on disease assessment of chronic rhinosinusitis, and to analyze the correlation between subjective and objective scores. Method:A total of 253 patients with chronic rhinosinusitis were enrolled from June 2016 to June 2017, and the clinical data such as sex, age, comorbidity, diagnosis and treatment were summarized. All patients were grouped as with or without nasal polyps, with or without eosinophilia, with or without allergic rhinitis group, and assessed by the visual analogue scale(VAS), Lund-Mackay CT score and Lund-Kennedy score respectively. The difference of the three grades in each group were analyzed by statistic analysis. The correlation between the three grades was analyzed. Result:Two hundred and fifty-three cases of chronic rhinosinusitis were included in the analysis. There were 143 males and 110 females with an average age of 44.44±15.44 years old, mostly in the 41-65 age group, and the difference was statistically significant (P<0.01). The scores of VAS, Lund-Mackay CT and Lund-Kennedy in the nasal polyp group were significantly higher than those in the non-nasal polyp group (P<0.05). The nasal endoscopy score of patients with allergic rhinitis was higher than that of non-allergic rhinitis group (P<0.01). There was no significant difference between VAS score, CT and endoscopic score in EOS group (P>0.05). There was a positive correlation between VAS score and nasal endoscopy score or CT score (P<0.01) in patients of non-allergic rhinitis or eosinophilia group, but there was no correlation (P>0.05) in patients with allergic rhinitis or eosinophilia group. There was no correlation when two or three factors exist at the same time beteen the nasal polyp, allergic rhinitis and EOS group (P>0.05), whereas show up positive correlation on non-merged group (P<0.01). Conclusion:Chronic rhinosinusitis complicated with nasal polyps or allergic rhinitis can significantly increase the subjective and objective symptoms of patients. There are differences between subjective symptoms and objective tests in the patients with nasal polyps, allergic rhinitis and EOS factors. Therefore, clinical attention should be paid to the impact of allergic factors on patients, using a variety of subjective and objective evaluation atrategies to evaluate the condition of patients with chronic rhinosinusitis comprehensively, to provide a basis for personalized diagnosis and treatment.

Graphene gas sensing using a non-contact microwave method

We report a non-contact CVD graphene gas sensing method that utilises a high Q microwave dielectric resonator perturbation technique. A graphene sample is coupled to the evanescent field of a dielectric resonator whereupon nitrogen dioxide (NO₂), a p-doping gas, is detected by monitoring the change in the linewidth and frequency of the resonant mode. The resonant peak shape is dependent on the number of carriers in the graphene sheet. Therefore, the linewidth perturbation can be converted to a measurement of the graphene sheet resistance. To demonstrate the strength of this technique, sensor response curves for NO₂ at different concentrations and temperatures are measured showing sub ppm sensitivity. This technique eliminates interactions between the trace gas and metal contacts that otherwise effect the sensor response of the graphene device.

New insight into the catalytic cycle about epoxidation of alkenes by N2O over a Mn-substituted Keggin-type polyoxometalate

Although epoxidation of alkenes by N₂O catalyzed by Mn-substituted polyoxometalates (POMs) has been studied both experimental and theoretical methods, a complete catalytic cycle has not been established currently. In the present paper, density functional theory (DFT) calculations were employed to explore possible reaction mechanism about this catalytic cycle. Our DFT studies reveal that the reaction pathway starts from a low-valent Keggin-type POM aquametal derivative [PW₁₁O₃₉Mn^IIIH₂O]^4-. In the presence of N₂O pressure, the formation of the active catalytic species [PW₁₁O₃₉Mn^VO]^4- involves a ligand-substituted reaction about replacement of the aqua ligand with N₂O to generation of POM/N₂O adduct [PW₁₁O₃₉Mn^IIION₂]^4- and dissociation of N₂ from this adduct. The calculated free energy indicates that the ligand-substituted reaction is endergonic both in gas phase or various solvents. The partial optimization method reveals that the dissociation of N₂ from [PW₁₁O₃₉Mn^IIION₂]^4- involves crossing of the quintet state with a low-lying triplet state. Due to the high reactivity, the high-valent Mn^V-oxo species, [PW₁₁O₃₉Mn^VO]^4-, may react with the excess N₂O and alkenes. Thus, two alternative reaction pathways corresponding to activation of N₂O and epoxidation of alkenes have been considered in this work. The calculated free energy profile indicates that epoxidation of alkenes pathway is the favorable routes. Finally, a complete catalytic cycle for this reaction has been proposed. The rate-determining step in this catalytic cycle is the dissociation of N₂ from the low-valent POM/N₂O adduct according to our DFT-M06L calculations.

Application of Finite Element Method in Traffic Injury and Its Prospect in Forensic Science

The finite element method （FEM） is a numerical computation method based on computer technology, and has been gradually applied in the fields of medicine and biomechanics. The finite element analysis can be used to explore the loading process and injury mechanism of human body in traffic injury. FEM is also helpful for the forensic investigation in traffic injury. This paper reviews the development of the finite element models and analysis of brain, cervical spine, chest and abdomen, pelvis, limbs at home and aboard in traffic injury in recent years.

The effect of Li doping on the nonlinear optical properties of [2.2]paracyclophane

The similar molecules [2.2]paracyclophane (22PCP) and 1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane (8F22PCP) have both generated considerable synthetic interest since they were first prepared. In this work, the nonlinear optical properties of 22PCP, 8F22PCP, and the related Li-doped systems 22PCP-Li and 8F22PCP-Li (which have a Li atom above 22PCP and 8F22PCP, respectively) were investigated. An analysis of natural bond orbital charges showed that there is greater charge transfer from the Li atom to the benzene rings in 8F22PCP-Li than in 22PCP-Li. The variation in the calculated nucleus independent chemical shift (NICS) value as a function of the distance from the lower benzene ring towards the upper benzene ring was found to be W-shaped for both 22PCP and 22PCP-Li. Moreover, whereas all of the NICS values of 22PCP and 22PCP-Li were markedly negative, all of the NICS values of 8F22PCP and 8F22PCP-Li were either positive or only moderately negative. Calculations of the electro-optical properties of these systems showed that the first hyperpolarizability of 22PCP-Li was noticeably larger than that of 8F22PCP-Li. According to the two-level model, the larger first hyperpolarizability of 22PCP-Li is due to its smaller transition energy.

Tetrathiafulvalene derivatives as cation sensor: density functional theory investigation of the hyper-Rayleigh scattering first hyperpolarizability

The hyper-Rayleigh scattering first hyperpolarizability of a series of extended tetrathiafulvalene (TTF) and TTF derivatives have been theoretically investigated using density functional theory to explore their use as potential cation sensor.

Computational study on redox-switchable second-order nonlinear optical properties of ferrocene-tetrathiafulvalene hybrid

Redox-switchable second-order nonlinear optical (NLO) responses of a series of ferrocene-tetrathiafulvalene (Fc–TTF) hybrids have been studied based on density functional theory calculations.

Regulation of autophagy by miR-30d impacts sensitivity of anaplastic thyroid carcinoma to cisplatin

miR-30d has been observed to be significantly down-regulated in human anaplastic thyroid carcinoma (ATC), and is believed to be an important event in thyroid cell transformation. In this study, we found that miR-30d has a critical role in modulating sensitivity of ATC cells to cisplatin, a commonly used chemotherapeutic drug for treatment of this neoplasm. Using a mimic of miR-30d, we demonstrated that miR-30d could negatively regulate the expression of beclin 1, a key autophagy gene, leading to suppression of the cisplatin-activated autophagic response that protects ATC cells from apoptosis. A reporter gene assay demonstrated that the binding sequences of miR-30d in the beclin 1-3' UTR was the region required for the inhibition of beclin 1 expression by this miRNA. We further showed that inhibition of the beclin 1-mediated autophagy by the miR-30d mimic sensitized ATC cells to cisplatin both in vitro (cell culture) and in vivo (animal xenograft model). These results suggest that dysregulation of miR-30d in ATC cells is responsible for the insensitivity to cisplatin by promoting autophagic survival. Thus, miR-30d may be exploited as a potential target for therapeutic intervention in the treatment of ATC.