Prediction of cerebral infarction after bypass surgery in adult moyamoya disease: using pulsatility index on TCD.

BACKGROUND: At present, the most effective treatment for symptomatic moyamoya disease (MMD) is surgery. However, the high incidence of postoperative complications is a serious problem plaguing the surgical treatment of MMD, especially the acute cerebral infarction. Decreased cerebrovascular reserve is an independent risk factor for ischemic infarction, and the pulsatility index (PI) of transcranial Doppler (TCD) is a common intuitive index for evaluating intracranial vascular compliance. However, the relationship between PI and the occurrence of ischemic stroke after operation is unclear. OBJECTIVE: To explore whether the PI in the middle cerebral artery (MCA) could serve as a potential predictor for the occurrence of ischemic infarction after bypass surgery in MMD. METHODS: We performed a retrospective analysis of data from 71 patients who underwent combined revascularization surgery, including superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-myo-synangiosis (EDMS). The patients were divided into two groups according to the median of ipsilateral MCA-PI before operation, low PI group (MCA-PI < 0.614) and high PI group (MCA-PI ≥ 0.614). Univariate and multivariate regression analysis were used to explore risk factors affecting the occurrence of postoperative cerebral infarction. RESULTS: Among the 71 patients with moyamoya disease, 11 patients had cerebral infarction within one week after revascularization. Among them, 10 patients' ipsilateral MCA-PI were less than 0.614, and another one's MCA- PI is higher than 0.614. Univariate analysis showed that the lower ipsilateral MCA-PI (0.448 ± 0.109 vs. 0.637 ± 0.124; P = 0.001) and higher Suzuki stage (P = 0.025) were linked to postoperative cerebral infarction. Multivariate analysis revealed that lower ipsilateral MCA-PI was an independent risk factor for predicting postoperative cerebral infarction (adjusted OR = 14.063; 95% CI = 6.265 ~ 37.308; P = 0.009). CONCLUSIONS: A lower PI in the ipsilateral MCA may predict the cerebral infarction after combined revascularization surgery with high specificity. And combined revascularization appears to be safer for the moyamoya patients in early stages.

Molecular epidemiology and antimicrobial resistance patterns of carbapenem-resistant Acinetobacter baumannii isolates from patients admitted at ICUs of a teaching hospital in Zunyi, China.

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a predominant strain of healthcare-associated infections worldwide, particularly in intensive care units (ICUs). Therefore, it is imperative to study the molecular epidemiology of CRAB in the ICUs using multiple molecular typing methods to lay the foundation for the development of infection prevention and control strategies. This study aimed to determine the antimicrobial susceptibility profile, the molecular epidemiology and conduct homology analysis on CRAB strains isolated from ICUs. Methods: The sensitivity to various antimicrobials was determined using the minimum inhibitory concentration (MIC) method, Kirby-Bauer disk diffusion (KBDD), and E-test assays. Resistance genes were identified by polymerase chain reaction (PCR). Molecular typing was performed using multilocus sequence typing (MLST) and multiple-locus variable-number tandem repeat analysis (MLVA). Results: Among the 79 isolates collected, they exhibited high resistance to various antimicrobials but showed low resistance to levofloxacin, trimethoprim-sulfamethoxazole, and tetracyclines. Notably, all isolates of A. baumannii were identified as multidrug-resistant A. baumannii (MDR-AB). The bla OXA-51-like, adeJ, and adeG genes were all detected, while the detection rates of bla OXA-23-like (97.5%), adeB (93.67%), bla ADC (93.67%), qacEΔ1-sul1 (84.81%) were higher; most of the Ambler class A and class B genes were not detected. MLST analysis on the 79 isolates identified five sequence types (STs), which belonged to group 3 clonal complexes 369. ST1145Ox was the most frequently observed ST with a count of 56 out of 79 isolates (70.89%). MLST analysis for non-sensitive tigecycline isolates, which were revealed ST1145Ox and ST1417Ox as well. By using the MLVA assay, the 79 isolates could be grouped into a total of 64 distinct MTs with eleven clusters identified in them. Minimum spanning tree analysis defined seven different MLVA complexes (MCs) labeled MC1 to MC6 along with twenty singletons. The locus MLVA-AB_2396 demonstrated the highest Simpson's diversity index value at 0.829 among all loci tested in this study while also having one of the highest variety of tandem repeat species. Conclusion: The molecular diversity and clonal affinities within the genomes of the CRAB strains were clearly evident, with the identification of ST1144Ox, ST1658Ox, and ST1646Oxqaq representing novel findings.

The efficacy of STA-MCA double anastomosis comparing to single anastomosis in chronic internal carotid artery occlusion patients.

OBJECTIVE: To investigate the efficacy of STA-MCA double-anastomosis and single-anastomosis in patients with cerebral hypoperfusion caused by chronic internal carotid artery occlusion(CICAO). METHODS: In this retrospective study, data were collected from 19 patients with CICAO who underwent STA-MCA anastomosis at our hospital between January 2016 and January 2022, and they were divided into single anastomosis group and double anastomosis group according to the surgical method. The study collected general clinical data from both groups, including age, sex, lipid levels, blood pressure, glucose levels, smoking and alcohol consumption. Additionally, pre- and postoperative neurological function, cerebral hemodynamic parameters, and postoperative ischemic events were also recorded. By combining our study findings with the existing literature, a comparative analysis of the efficacy of single- and double-anastomosis in patients with CICAO was conducted. RESULTS: Prior to surgical treatment，there were no statistically significant differences in cerebral hemodynamic parameters, including rob (0.65 ± 0.09 VS. 0.62 ± 0.04), rut (1.73 ± 0.40 VS. 1.99 ± 0.53), and rTMax (2.02 ± 0.49 VS. 1.72 ± 0.46), as well as neurofunctional scores, including modified Rankin Scale (MRS) (2.8 ± 1.03 VS. 2.4 ± 0.88) and National Institutes of Health Stroke Scale (NIHSS) (9.1 ± 5.08 VS. 8.3 ± 4.09) between the two groups. After operation, rCBF (single: 0.65 ± 0.09 VS.0.84 ± 0.08, p = 0.007; double: 0.62 ± 0.04 VS.1.08 ± 0.20, p = 0.001) were significantly increased in both groups, but the rMTT (1.99 ± 0.53 VS.1.27 ± 0.42, p = 0.0447) and rTMax (1.72 ± 0.46 VS.1.16 ± 0.16, p = 0.038) showed significant differences postoperatively only in the double-anastomosis group. The MRS (single: 1.8 ± 1.23, double: 1.7 ± 0.9) in both groups and the NIHSS (7.2 ± 5.11) in single-anastomosis group were not improved after surgery, while the NIHSS (8.3 ± 4.09 VS.4.4 ± 3.08, p = 0.037) in double-anastomosis group was improve significantly. In summary, the double-anastomosis group showed better improvement in rCBF and NIHSS scores compared to the single-anastomosis group.(ΔrCBF: 0.19±0.09 VS. 0.45±0.18, p=0.02, ΔNIHSS: 1.9±0.56 VS. 4±1.73, p=0.002). The cases were followed up for 20.3 ± 18.6 months, and there were no ischemic events in either group during the follow-up period. CONCLUSION: STA-MCA revascularization can improve CBF in patients with hypoperfusion caused by CICAO, and prevent the reoccurrence of ischemic stroke effectively. Compared with single-anastomosis, double-anastomosis can provide more CBF and improve neurologic dysfunction.

Antimicrobial Resistance Patterns, Sequence Types, Virulence and Carbapenemase Genes of Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates from a Tertiary Care Teaching Hospital in Zunyi, China.

Purpose: Carbapenem-resistant Klebsiella pneumoniae (CRKP) has seriously threatened public health worldwide. This study aimed to investigate the antimicrobial resistance patterns, sequence types (STs), virulence and carbapenemase genes of CRKP isolates from patients in Zunyi, China. Methods: CRKP isolates were collected from the First People's Hospital of Zunyi between January 2018 and December 2020. Antimicrobial susceptibility was determined using a VITEK®2 analyzer and confirmed using either the broth dilution method, Kirby-Bauer method, or E-test assays. Carbapenemase production was examined using a modified carbapenem inactivation method. STs of the studied isolates were determined by multilocus sequence typing, and the presence of carbapenemase and virulence genes was examined using polymerase chain reaction assays. Results: In total, 94 CRKP isolates were collected. All studied isolates produced carbapenemase, and the most common carbapenemase gene was New Delhi metallo-ß-lactamase (NDM; 72.3%), followed by Klebsiella pneumoniae carbapenemase (KPC; 24.5%), and Verona integron-encoded metallo-ß-lactamase (VIM; 3.2%). Of the studied isolates, 74.3% exhibited multidrug-resistant (MDR) phenotype, and 25.7% were either pandrug-resistant (PDR) or extensively drug-resistant (XDR) phenotypes. The most prevalent sequence type was ST2407 (37.2%), followed by ST76 (21.3%) and ST11 (11.7%). The NDM gene was present in 97.1% of ST2407 isolates and 90.0% of ST76 isolates, whereas the KPC gene was present in 90.9% of ST11 isolates. The majority of the isolates carried wabG, uge, and fimH virulence genes, with prevalence rates of 94.7%, 92.6%, and 94.7%, respectively. Conclusion: This study describes NDM-producing ST2407 and ST76, as well as KPC-producing ST11, as the major clonal types of CRKP isolates in Zunyi, China. All CRKP isolates were resistant to multiple types of antibiotics, and the majority of isolates carried carbapenemase and virulence genes. Clonal spread of NDM-producing CRKP ST2407 and ST76, and KPC-producing CRKP ST11 should be strictly monitored.

A Dynamic Constitutive Model and Simulation of Braided CFRP under High-Speed Tensile Loading.

In this study, a dynamic constitutive model for woven-carbon-fiber-reinforced plastics (CFRP) is formulated by combining dynamic tensile test data and fitting curves and incorporating variation rules established for the modulus of elasticity, strength, and fracture strain with respect to the strain rate. The dynamic constitutive model is then implemented with finite element software. The accuracy and applicability of the dynamic constitutive model are evaluated by comparing the numerically predicted load-displacement curves and strain distributions with the test data. The stress distribution, failure factor, modulus, and strength of the material under dynamic tension are also explored. The results show that the response simulated with the dynamic constitutive model is in good agreement with the experimental results. The strain is uniformly distributed during the elastic phase compared with the DIC strain field. Subsequently, it becomes nonuniform when stress exceeds 600 MPa. Then, the brittle fracture occurs. With the increase in the strain rate, the input modulus decreased, and the tensile strength increased. When the displacement was 0.13 mm, the simulation model was damaged at a low strain rate, and the stress value was 837.8 MPa. When it reached the high strain rate of 800 s-1, no failure occurred, and the maximum stress value was 432.5 MPa. For the same specimen, the strain rate was the smallest on both clamped ends, and the modulus and strength were large at the ends and small in the middle. The fitting curve derived from the test data was completely input into the dynamic constitutive model to better capture the dynamic change in the material properties.

A perylenediimide modified SiO2@TiO2 yolk-shell light-responsive nanozyme: Improved peroxidase-like activity for H2O2 and sarcosine sensing.

Although light-responsive nanozyme have been widely used in colorimetric sensing, some limitations such as poor catalytic activity, low detection efficiency, and unclear structure-activity relationships remain unresolved. Herein, we prepared an excellent light-responsive peroxidase (POD) mimic, perylenediimide (PDI-OH) modified SiO2 @TiO2 yolk-shell spheres (SiO2 @TiO2/PDI-OH), based on DFT-assisted design. The experiment and DFT calculation revealed that the enhanced POD-like activity was mainly attributed to a suitable built-in electric field among adjacent PDI-OH molecules on the surface of the SiO2 @TiO2 and the unique yolk-shell structure with more reaction sites of SiO2 @TiO2. Consequently, the highly selective and ultrasensitive detection of H2O2 is achieved with a detection limit (LOD) of 7.6 × 10-8M. Further, the selective detection of sarcosine with LOD of 1.2 × 10-7 M was also achieved by introducing sarcosine oxidase (SOx). This colorimetric assay is successfully applied to selectively detect H2O2 and sarcosine levels in real samples. Controlled response time, anti-interference, and the robustness of the developed colorimetric sensor are the key advantages. And the present work firstly clarifies the effect of PDIs substituents on the POD-like activity of light-responsive nanozymes and provided new guidelines to develop high-performance nanozymes for hazardous substances detection.

Embedding SnO2 Thin Shell Protected Ag Nanowires in SnO2 ETL to Enhance the Performance of Perovskite Solar Cells.

The energy level mismatching between SnO2 and perovskite and the nonradiative recombination at SnO2-perovskite interface severely degrade the extraction of carriers, reducing the power conversion efficiency (PCE) and stability of planar perovskite solar cells (PSCs) based on SnO2 electron transfer layer (ETL). In the present work, a reinforced SnO2 ETL was successfully developed by embedding SnO2 thin shell protected Ag nanowires (Ag/SnO2 NWs) in traditional planar SnO2 film, which was proved to not only lower the conduction band of SnO2 to adjust the energy level matching, but also significantly reduce the interfacial carrier recombination. Moreover, Ag/SnO2 NWs improved the electrical conductivity of SnO2 ETL, and effectively promoted carrier transport. Benefiting from the use of Ag/SnO2 NWs, our newly designed PSC achieved a significantly increased champion PCE of 19.78%, which is 7% higher than the traditional PSC without Ag/SnO2 NWs embedding, indicating its great application potential in PSCs.

The F-box gene Ppa promotes lipid storage in Drosophila.

Lipid is one of the important components of living organisms. The precise regulation and homeostasis maintenance of lipid metabolism are essential to human health. The ubiquitination pathway regulates lipid metabolism by degrading lipid-related proteins. Ppa encodes an F-box protein, which is a member of the SCF ubiquitination complex. Previous studies reported that Ppa regulated the body segmentation and the correct localization of centromere histones, while its function in lipid metabolism has not been reported. In this study, Drosophila melanogaster was used to explore the function of Ppa in lipid storage. The subcellular localization of PPA was detected by fusion with green fluorescent protein. The deletion mutant of Ppa was constructed via CRISPR/Cas9 technology. The morphological changes of lipid droplets in deletion mutants and Ppa overexpression flies were analyzed by BODIPY 493/503 or Nile red staining. Further, Ppa was overexpressed in the deletion mutant to verify its function. The results showed that PPA-GFP fusion protein were localized in the nuclei of salivary gland and fat body. Compared with the control flies, the lipid droplets in Ppa deletion mutants became smaller, and overexpression of Ppa exhibited larger lipid droplets. Overexpression of Ppa in the deletion mutant could restore the lipid droplets to normal state. In summary, this study demonstrated that Ppa could promote lipid storage in Drosophila.

Fatigue Crack Growth Behaviour of Precipitate-Strengthened CuNi2Si Alloy under Different Loading Modes.

In this study, fatigue crack tests of CuNi2Si alloys using the replica technique under symmetrical tensile-compression loading, and rotational-bending loading were carried out with the same nominal stress amplitude. Observation and analysis results indicate that under different load types, the cracks display a trend of slow initiation growth and then rapid growth. The critical point is identified at the approximate value of 0.8 of the fatigue life fraction, and the crack growth rate of the sample under tensile-compression load is approximately an order of magnitude higher than that under rotational-bending load, resulting in the average life of the former being significantly shorter than the latter. Combining the observation results of the fractographical analysis and the surface-etched sample replica film, it can be seen that whether it is a tensile-compression load or a rotational-bending load, cracks mainly propagate in intergranular mode after initiation.

Comparative Study on Vibration Fatigue Characteristics of Fuel Tank Material in Fuel and Air Media.

To quantify the influence of the fuel medium on the fatigue performance of fuel tank materials, a comparative study was performed on the vibration fatigue characteristics of parent material specimens in fuel and air media. A fluid-solid coupling model was established based on the virtual mass method. Meanwhile, vibration fatigue tests of Q235BF specimens were performed in fuel and air media. The quantitative relation of the fatigue life of specimens in the air medium and that in the fuel medium was obtained. Fracture observation and energy spectrum analysis revealed the influence law of fuel on notches of specimens. The modal analysis of the finite element model proves that the stress of the specimens in the fuel medium is larger than that in the air medium. In this condition, they have shorter life. Finally, four approaches were used to calculate the fatigue life of the specimens to compare with the test life. The reasonable fatigue life prediction method was obtained in the case of fuel and air media.

Simulation Study of Adhesive Material for Sandwich Panel under Edgewise Compression Condition.

In order to study the interfacial adhesive material simulation method of a sandwich structure with aluminum alloy panels and a low-density foam core under edgewise compression condition, two finite element models were defined using material model no. 185 (MAT 185) adhesive element and tiebreak contact, respectively, by LS-DYNA. Under the conditions of different loading rates, and element sizes, the effects of peak load, energy absorption, failure mode of adhesive layer and the influence degree of the changing condition on the calculated results were compared between the two models, and then compared with the experiment results and theoretical results. The higher the loading rate was, or the smaller the element size was, the higher the peak load was. The simulation results obtained using MAT 185 were closer to the experimental results under the edgewise compression condition.

Self-Supported PANI@MnO2 Coaxial Nanowire Network Sponge as a Binder Free Electrode for Supercapacitors.

In this paper, we report a novel self-supported PANI@MnO2 coaxial nanowire network sponge as a binder free electrode for supercapacitors. The as-prepared material has long MnO2 nanowire core, uniform PANI shell, intertwined nanowire networks and sponge-like structure. Its unique structure promotes the conductivity, electrochemical performance and stability of the material. The specific capacitance of this PANI@MnO2 coaxial nanowire network sponge electrode was as high as 344 F·g-1 and maintained about 98.6% of its initial value. Moreover, a high energy density of 86 Wh·kg-1 at a power density of 400 W·kg-1 was obtained tested by a symmetric capacitor. This remarkable electrochemical performance indicated its superior application potential in supercapacitors.

Study on Short Fatigue Crack Behaviour of LZ50 Steel Under Non-Proportional Loading.

The low cycle fatigue tests using the replica technique for LZ50 steel under non-proportional cyclic loading were carried out, and eight groups of effective test data were obtained. The evolution behaviour of short cracks was studied based on the effective short cracks criterion. The results show that short cracks generally originate in the grain or along the grain boundary. At the microstructural short crack stage, the crack propagation is influenced strongly by the microstructure of the material, and the growth rate of the short crack slows down several times according to the number of obstacles encountered. At the physical short crack stage, the crack propagation breaks through the banded structure of pearlite. Thus, the dominant effective short fatigue crack is formed, and the crack growth rate increases rapidly. Based on the modified parameters of the uniaxial short crack model, an approach is presented to calculate the growth rate of short cracks under multi-axial non-proportional loadings, and the new model can consider the non-proportional factor F. The fitting results of the multi-axial microstructural obstacles model are compared with test data. The comparison results show that this model can reflect the trend of short fatigue crack propagation rate under non-proportional loadings.

Hierarchical NiO Nanoflake Arrays on Nickel Foam as a Supercapacitor Electrode with High Capacitance and High Rate Capability.

In this paper, we report a simple and cost-effective method for fabricating hierarchical NiO nanoflake arrays on nickel foam. X-ray diffraction, scanning electron microscope and transmission electron microscope are employed to study the morphology and structure of the as-synthesized NiO materials. Galvanostatic charge/discharge measurements demonstrate that the hierarchical NiO nanocomposite displays excellent capacitive behavior between the potential range of -0.1-0.5 V, and a maximum specific capacitance as high as 823 F g-1 can be achieved at a charge/discharge current density of 4 A g-1, and it only decreases by 20% when the current density increases to 12 A g-1. The remarkable electrochemical performance of this hierarchical NiO nanocomposite indicates the areat application potential in supercapacitors.

The competitive O-H versus C-H bond activation of ethanol and methanol by VO2(+) in gas phase: a DFT study.

The activation of ethanol and methanol by VO2(+) in gas phase has been theoretically investigated by using density functional theory (DFT). For the VO2(+)/ethanol system, the activation energy (ΔE) is found to follow the order of ΔE(C(ß)-H) < ΔE(C(α)-H) ≈ ΔE(O-H). Loss of methyl and glycol occurs respectively via O-H and C(ß)-H activation, while acetaldehyde elimination proceeds through two comparable O-H and C(α)-H activations yielding both VO(H2O)(+) and V(OH)2(+). Loss of water not only gives rise to VO(CH3CHO)(+) via both O-H and C(α)-H activation but also forms VO2(C2H4)(+) via C(ß)-H activation. The major product of ethylene is formed via both O-H and C(ß)-H activation for yielding VO(OH)2(+) and VO2(H2O)(+). In the methanol reaction, both initial O-H and C(α)-H activation accounts for formaldehyde and water elimination, but the former pathway is preferred.

Patterned 3-dimensional metal grid electrodes as alternative electron collectors in dye-sensitized solar cells.

We describe the application of 3-dimensional metal grid electrodes (3D-MGEs) as electron collectors in dye-sensitized solar cells (DSCs) as a replacement for fluorinated tin oxide (FTO) electrodes. Requirements, structure, advantages, and limitations of the metal grid electrodes are discussed. Solar conversion efficiencies of 6.2% have been achieved in 3D-MGE based solar cells, comparable to that fabricated on FTO (7.1%). The charge transport properties and collection efficiencies in these novel solar cells have been studied using electrochemical impedance spectroscopy.

Mesoporous nanowire array architecture of manganese dioxide for electrochemical capacitor applications.

Mesoporous MnO(2) nanowire array architecture exhibits enhanced capacitive and charge/discharge performance for electrochemical capacitors.

Electrodeposited nickel hydroxide on nickel foam with ultrahigh capacitance.

Electrodeposited Ni(OH)(2) on nickel foam with porous and 3D nanostructures has ultrahigh capacitance in the potential range -0.05-0.45 V, and a maximum specific capacitance as high as 3152 F g(-1) can be achieved in 3% KOH solution at a charge/discharge current density of 4 A g(-1).

[Structural and optical characterization of ZnO thin films grown by plasma-assisted molecular beam epitaxy].

High-quality ZnO thin films were grown by plasma-assisted molecular beam epitaxy (P-MBE) on Al2 O3 (0001) substrate with a low temperature ZnO buffer layer. Structural and optical characterization were studied for ZnO thin films. Only a peak at (0002) were observed in the X-ray reflectivity (XRD) spectra with the full-width at half maximum (FWHM) value 0.18 degrees, and two peaks 1LO (579 cm(-1)) and 2LO (1 152 cm(-1)) were detected in the resonance Raman scattering spectra at room temperature. These results indicated that ZnO thin films had single orientation of c axis and high-quality of crystal wurtzite structure. The absorption of free-exciton and exciton-LO phonon appeared in the absorption spectra, which confirmed that the exciton state in the ZnO thin films were stable even at room temperature. And the energy spacing between these two peaks is 71.2 meV, corresponds to the longitudinal optical phonon energy of 71 meV of ZnO. Besides, from the photoluminescence spectra, no defect-related deep emission were observed, but just a remarkable free-exciton emission located at 376nm were obtained at room temperature, it proved that the ZnO thin films had high-quality but low density of defect.

[Impedance effects of interleukin-6 on cyclophosphamide-induced hematopoietic damnification in dogs].

The aim of this study is to evaluate the effect of Interleukin-6 on cyclophosphamide-induced hematopoietic damnification. The doses of Interleukin-6 in 3 different regimens were hypodermally injected into dogs for 7 days respectively to establish the cyclophosphamide-induced hematopoietic damnification model. The effect of Interleukin-6 on the production of platelets and the amount of other cells in the dogs' bone marrow were determined on the 21st day. The results showed that Interleukin-6 significantly alleviated the reduction of platelet count and recovered the platelets level faster. The impedance effects of Interleukin-6 directed against hematopoietic damnification of bone marrow and spleen were shown by pathological examination. These suggest that the Interleukin-6 can significantly impede cyclophosphamide-induced hematopoietic damnification.