Strengthening Cracked Steel Plates with Shape Memory Alloy Patches: Numerical and Experimental Investigations.

To investigate the retarding effect of bonding the shape memory alloy (SMA) patches on crack propagation in steel plates, both numerical and experimental analyses were conducted in the present study. A compact tension (CT) model was developed to clarify the feasibility of bonding the SMA patch to the reinforcement of the mode Ⅰ, mode Ⅱ, and mode Ⅲ cracks. On this basis, parametric analysis was conducted to investigate the strengthening parameters, i.e., the bonding area, the thickness, and the strengthening angle of the SMA patch. Subsequently, fatigue tests on the unreinforced steel plate and cracked steel plate strengthened by the SMA patches were conducted. The monitored stress variation, crack propagation behavior, and fatigue fracture surfaces were analyzed. Findings are meaningful to the application of the SMA reinforcement method in practical engineering.

Effective Notch-Stress-Based Stress Concentration Factors of the Rib-Deck Weld in Orthotropic Steel Decks Considering the Effect of Asphalt Surfacing.

Effective notch stress (ENS) approaches have many application prospects in fatigue damage assessments; however, an ENS can only be obtained by conducting complex and time-consuming numerical analyses, deterring many engineers from applying such an approach. In terms of the rib-deck weld in orthotropic steel decks (OSDs), predictive formulae for determining the ENS concentration factors (ENS-based SCFs) have been proposed; however, the effect of asphalt surfacing is not involved, which limits their applications in practical engineering. In the present study, refined finite element (FE) models, including asphalt surfacing, were developed to obtain the ENS-based SCFs which could be applied to practical engineering. Parametric analyses were conducted to investigate the effect of the transverse loading position, the combined effect of the transverse loading position and asphalt surfacing, and the effect of the temperature of the asphalt surfacing. The amplification coefficients (kSCF, kSCF1, and kSCF2) were introduced to determine the ENS-based SCFs on the basis of the predictive formulae without considering the effect of asphalt surfacing. Results show that the ENS-based SCFs of the rib-deck weld is considerably affected by the transverse position of wheel loading and the asphalt surfacing. The cubic polynomial function could be employed to fit the numerical results of the ENS-based SCFs and amplification coefficients (kSCF, kSCF1, and kSCF2) with high fitting precision. Predictive formulae for determining the ENS-based SCFs corresponding to arbitrary transverse loading position and temperature of asphalt surfacing are proposed. The validation investigation turns out that the relative error of the proposed formulae is within 10%, indicating the feasibility of using this approach for engineering applications.

Gastrointestinal Talaromyces marneffei infection in a man with AIDS: A case report.

RATIONALE: Reports of intestinal Talaromyces marneffei infection have increased year by year, but those of gastric infection remain rare. Here, we report disseminated talaromycosis with gastric and intestinal ulcers in an AIDS patient who was treated by antifungal agents and a proton pump inhibitor and achieved a satisfactory outcome. PATIENT CONCERNS: A 49-year-old man developed a gastrointestinal illness with main abdominal distension, poor appetite and a positive HIV infection to our AIDS clinical treatment center. DIAGNOSES: Electronic gastrointestinal endoscopy showed that the patient had multiple ulcers in the gastric angle, gastric antrum and large intestine. Gastric Helicobacter pylori infection was ruled out by paraulcerative histopathological analysis and a C14 urea breath test. The diagnosis was confirmed by gastroenteroscopic biopsy and metagenomic next-generation sequencing of gastric ulcer tissue. INTERVENTIONS: Symptomatic and supportive treatments [a proton pump inhibitor and gastrointestinal motility promotion] were initiated. The patient was prescribed sequential antifungal therapy with amphotericin B (0.5 mg/kg·d, 2 weeks) and itraconazole (200 mg, q12h, 10 weeks), and then followed with itraconazole for long-term secondary prevention (200 mg, qd). OUTCOMES: The combined use of antifungal agents and a proton pump inhibitor improved the patient's condition, and he was discharged home 20 days later. He had no gastrointestinal symptom during 1 year of telephone-based follow-up. LESSONS: In endemic areas, clinicians should be alert to the possibility of Talaromyces marneffei infection presenting with gastric ulcers in patients with AIDS, after excluding Helicobacter pylori infection.

Magnetically triggered drug release from nanoparticles and its applications in anti-tumor treatment.

The objective of this study was to describe the magnetic nanoparticle-drug conjugates for improved control of drug delivery and drug release. The widely used anticancer agent Doxorubicin (DOX) was successfully conjugated via amine groups to the carboxylic functional groups coating magnetic nanoparticles (fluidMAG-CMX). Following purification of the nanoparticles, the conjugation of DOX on fluidMAG-CMX was confirmed using FTIR spectroscopy and confocal microscopy. The observed drug loading capacity of DOX was 22.3%. Studies of magnetically triggered release were performed under an oscillating magnetic field (OMF). DOX exhibited a significant release percentage of 70% under an OMF, as compared with the release in enzyme. A magnetic field turn-on and turn-off experiment was also conducted to confirm the control of drug release using this triggered system. In vivo experiments indicated that the tumor-inhibitory rate of CMX-DOX NPs under a magnetic field was higher than the other control groups. According to the toxicity assessments, CMX-DOX NPs were not noticeably toxic to mice at our tested dose.