The effect of melt mixing on the interaction between multi-walled carbon nanotubes (MWNTs) and polystyrene (PS) matrix has been investigated. The interaction between pristine MWNTs and PS in solution ...was found to exist but not strong enough to allow MWNTs to be soluble in solvent. In contrast, this interaction between MWNTs and PS was significantly enhanced by melt mixing, which led to increased amount of PS-functionalized MWNT exhibiting good solubility in some solvents. The mechanism of melt mixing on this enhanced interaction was attributed to both chemical bonding and physical interaction during the melt mixing.
Dynamic membrane protrusions such as lamellipodia and filopodia are driven by actin polymerization and often hijacked by intracellular microbes to enter host cells. The overall rate of membrane ...protrusion depends on the actin polymerization rate and the increase of localized cell volume. Although the signaling pathways involving actin polymerization are well characterized, the molecular mechanisms regulating local cell volume associated with membrane protrusion are unclear. Cryptosporidium parvum, an intracellular parasite, depends on host-cell membrane protrusion to accomplish cell entry and form the parasitophorous vacuole. Here, we report that C. parvum infection of cholangiocytes recruits host-cell SGLT1, a Na+/glucose cotransporter, and aquaporin 1 (AQP1), a water channel, to the attachment site. SGLT1-dependent glucose uptake occurs at the attachment site. Concordantly, the region of attachment displays localized water influx that is inhibited by either suppression of AQP1 by means of AQP1-small interfering RNA (siRNA) or inhibition of SGLT1 by a specific pharmacologic inhibitor, phlorizin. Inhibition of SGLT1 does not affect actin accumulation but decreases the membrane protrusion at the attachment site. Moreover, functional inhibition of host-cell AQP1 and SGLT1 hampers C. parvum invasion of cholangiocytes. Thus, glucose-driven, AQP-mediated localized water influx is involved in the membrane protrusion during C. parvum cellular invasion, phenomena that may also be relevant to the mechanisms of cell membrane protrusion in general.
Purpose: Distinguishing latent tuberculosis infection (LTBI) from active tuberculosis (ATB) is important to control the prevalence of tuberculosis; however, there is currently no effective method. ...The aim of this study was to discover specific metabolites through fecal untargeted metabolomics to discriminate ATB, individuals with LTBI, and healthy controls (HC) and to probe the metabolic perturbation associated with the progression of tuberculosis. Patients and Methods: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to comprehensively detect compounds in fecal samples from HC, LTBI, and ATB patients. Differential metabolites between the two groups were screened, and their underlying biological functions were explored. Candidate metabolites were selected and enrolled in LASSO regression analysis to construct diagnostic signatures for discriminating between HC, LTBI, and ATB. A receiver operating characteristic (ROC) curve was applied to evaluate diagnostic value. A nomogram was constructed to predict the risk of progression of LTBI. Results: A total of 35 metabolites were found to exist differentially in HC, LTBI, and ATB, and eight biomarkers were selected. Three diagnostic signatures based on the eight biomarkers were constructed to distinguish between HC, LTBI, and ATB, demonstrating excellent discrimination performance in ROC analysis. A nomogram was successfully constructed to evaluate the risk of progression of LTBI to ATB. Moreover, 3,4-dimethylbenzoic acid has been shown to distinguish ATB patients with different responses to etiological tests. Conclusion: This study constructed diagnostic signatures based on fecal metabolic biomarkers that effectively discriminated HC, LTBI, and ATB, and established a predictive model to evaluate the risk of progression of LTBI to ATB. The results provide scientific evidence for establishing an accurate, sensitive, and noninvasive differential diagnosis scheme for tuberculosis. Keywords: feces, latent tuberculosis infection, active tuberculosis, biomarkers, progression, metabolomics
A three-dimensional thermo-elasto-plastic finite element analysis is used to determine the residual stress distribution and the distortion field in butt and fillet plates. The employed finite element ...model is first verified against existing experimental results of thermal distortion and then is used for analyzing 12 case studies accounting for various plate thicknesses and welding sequences. Weld induced residual stress distributions have been estimated and discussed. The effects of thickness, welding sequences and finite element size have been investigated. A two-dimensional parametric relationship of residual stresses has been developed.
A series of single-cell, hydrogen-air proton exchange membrane fuel cells (PEMFCs) was operated for different lengths of time, namely, 200, 500, 700, and 1000 h. A group of reproducible and identical ...membrane electrode assemblies (MEAs) was used for those tests. Cell performance was studied by examining the cell polarization curves. After various lifetime tests, each MEA was cross-cut and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy, and Raman techniques to investigate any changes in catalyst structure and morphology, as well as particle size and chemical composition. The average particle size of the catalysts was calculated from XRD results and was found to increase with cell operating time. In addition, the agglomeration in nanometer-sized catalyst particles was observed from TEM analysis after prolonged cell operation. Ruthenium oxide was identified from Raman spectra of the anode catalyst from the tested MEAs, while no oxides were found on the cathode catalyst at the cell operating voltage. It is possible that the formation of metal oxides at the surface of the anode catalyst led to larger particles and ultimately resulted in the decrease of catalyst activity. This might be responsible for the slightly degraded cell performance following 700 h of operation.
A traditional Ti-13Zr-21Cu-9Ni (wt.%) filler metal was used to join Ti sub(3)Al-based alloy and TiAl intermetallics, and the joints brazed at 1213-1233 K for 600s presented a shear strength of ...113-149 MPa at room temperature. For the improvement of the joint strength a Ti-Zr-Cu-Ni-Co filler metal was designed. The shear strength of the joints brazed with the Ti-Zr-Cu-Ni-Co filler at 1283 K for 300 s reached 278 MPa, increased about 86.6% compared with the Ti-Zr-Cu-Ni system filler. The overall hardness in the joint brazed with the Ti-Zr-Cu-Ni-Co filler was uniformly lower than the joint brazed with Ti-Zr-Cu-Ni filler. The Ti sub(3)Al/TiAl joint brazed with Ti-Zr-Cu-Ni mainly consisted of Ti sub(2)Al, alpha sub(2)-Ti sub(3)Al and the residual filler metal of Ti(Cu, Al) sub(2) + CuZr. The phase sequence within the Ti sub(3)Al/TiAl joint brazed with Ti-Zr-Cu-Ni-Co filler from TiAl side to Ti sub(3)Al side can be described as the follows: TiAl substrate/Ti sub(2)Al + alpha sub(2)-Ti sub(3)Al/ alpha sub(2)-Ti sub(3)Al + Ti-rich phase/residual filler metal/Ti-rich phase/Ti-rich phase + O-Ti sub(2)AlNb/Ti sub(3)Al substrate, and the fracture surface of the corresponding joint was characterized by Ti-rich phase, indicating that compared with the traditional Ti-Zr-Cu-Ni filler the joint ductility was increased to a great extent.
Bi-2212 wires, which have high critical current density and critical magnetic field without anisotropy, offer significant potential applications for ultrahigh-field superconducting magnets. The ...Bi-2212 wire is very sensitive to strain. The strands are inevitably subjected to cyclic thermal or electromagnetic stress during application. There is a lack of understanding regarding the fatigue properties. In this paper, the degradation behavior of critical current for Bi-2212 wires under axial tensile fatigue loading was investigated. It was found that the fatigue life decreases with the increase in maximum fatigue stress.
This study aimed to simplify the version-1 Chinese and Western medication adherence scale for patients with chronic kidney disease (CKD) to a version-2 scale using item response theory (IRT) ...analyses, and to further evaluate the performance of the version-2 scale.
Firstly, we refined the version-1 scale using IRT analyses to examine the discrimination parameter (a), difficulty parameter (b) and maximum information function peak (Imax). The final scale refinement from version-1 to version-2 scale was also decided upon clinical considerations. Secondly, we analyzed the reliability and validity of version-2 scale using classical test theory (CTT), as well as difficulty, discrimination and Imax of version-1 and version-2 scale using IRT in order to conduct scale evaluation.
For scale refinement, the 26-item version-1 scale was reduced to a 15-item version-2 scale after IRT analyses. For scale evaluation using CTT, internal consistency reliability (total Cronbach α = 0.842) and test-rest reliability (r = 0.909) of version-2 scale were desirable. Content validity indicated 3 components of knowledge, belief and behaviors. We found meritorious construct validity with 3 detected components as the same construct of medication knowledge (items 1-9), medication behavior (items 13-15), and medication belief (items 10-12) based upon exploratory factor analysis. The correlation between the version-2 scale and Morisky, Green and Levine scale (MGL scale) was weak (Pearson coefficient = 0.349). For scale evaluation with IRT, the findings showed enhanced discrimination and decreased difficulty of most retained items (items 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15), decreased Imax of items 1, 2, 3, 4, 6, 11, 14, as well as increased Imax of items 5, 7, 8, 9, 10, 12, 13, 14, 15 in the version-2 scale than in the version-1 scale.
The original Chinese and Western medication adherence scale was refined to a 15-item version-2 scale after IRT analyses. The scale evaluation using CTT and IRT showed the version-2 scale had the desirable reliability, validity, discrimination, difficulty, and information providedoverall. Therefore, the version-2 scale is clinically feasible to assess the medication adherence of CKD patients.
To analyze the incidence and clinical phenotype of the concomitant extragenital malformations in the patients with female reproductive tract anomalies.
A retrospective study was conducted using ...clinical data of hospitalized patients diagnosed with uterine, cervical, or vaginal malformations from January 2003 to December 2022 in Peking Union Medical College Hospital. The malformations were classified according to American Society for Reproductive Medicine müllerian anomalies classification 2021, and in each type, the incidence and specific manifestations of concomitant extragnital malformations were analyzed.
A total of 444 patients were included. The overall incidence of concomitant extragenital malformations was 43.5% (193/444), including urinary system, skeletal system, and other system malformations. Renal malformations on the obstructed side were present in all patients with oblique vaginal septum syndrome (100.0%, 78/78). The total incidence of concomitant extragnital malformations was as high as 8/11 in
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