Many urinary tract infections (UTIs) are recurrent because uropathogens persist within the bladder epithelial cells (BECs) for extended periods between bouts of infection. Because persistent uropathogens are intracellular, they are often refractive to antibiotic treatment. The recent discovery of endogenous Lactobacillus spp. in the bladders of healthy humans raised the question of whether these endogenous bacteria directly or indirectly impact intracellular bacterial burden in the bladder. Here, we report that in contrast to healthy women, female patients experiencing recurrent UTIs have a bladder population of Lactobacilli that is markedly reduced. Exposing infected human BECs to L. crispatus in vitro markedly reduced the intracellular uropathogenic Escherichia coli (UPEC) load. The adherence of Lactobacilli to BECs was found to result in increased type I interferon (IFN) production, which in turn enhanced the expression of cathepsin D within lysosomes harboring UPECs. This lysosomal cathepsin D–mediated UPEC killing was diminished in germ-free mice and type I IFN receptor–deficient mice. Secreted metabolites of L. crispatus seemed to be responsible for the increased expression of type I IFN in human BECs. Intravesicular administration of Lactobacilli into UPEC-infected murine bladders markedly reduced their intracellular bacterial load suggesting that components of the endogenous microflora can have therapeutic effects against UTIs.
This paper presents a modified Split Hopkinson Pressure Bar (SHPB) technique to obtain compressive stress strain data for NBR rubber materials. An experimental technique with a modified the conventional SHPB has been developed for measuring the compressive stress strain responses of materials with low mechanical impedance and low compressive strengths, such as the rubber and the polymeric material. This paper uses an aluminum pressure bar to achieve a closer impedance match between the pressure bar and the specimen materials. In addition, a pulse shaper is utilized to lengthen the rising time of the incident pulse to ensure dynamic stress equilibrium and homogeneous deformation of NBR rubber materials. It is found that the modified technique can determine the dynamic deformation behavior of rubbers more accurately.
A specific experimental method, the split Hopkinson pressure bar (SHPB) technique is used to determine the dynamic material properties under the impact compressive loading condition with strain-rate of the order of 10 3 /s~10 4 /s. The dynamic deformation behavior of rubber materials widely used for the isolation of vibration from varying structures under dynamic loading is determined by using the Split Hopkinson Pressure Bar technique. The relationships between the stresses at transition points of rubber materials and the strain rate are found to be bilinear. However, an interesting relationship between the strains at transition points of rubber materials and the strain rate, which needs further investigation, is noted.
Inconel 713C alloy was tried to manufacture by using MIM(Metal Injection Molding) process. The high-temperature mechanical properties of MIMed Inconel 713C were also investigated. Processing defects such as pores and binders could be observed near the surface. Tensile tests were conducted from room temperature to 900°C. The result of tensile tests showed that this alloy had similar or somewhat higher strengths (YS: 734 MPa, UTS: 968 MPa, elongation: 7.16 % at room temperature) from RT to 700°C than those of conventional Inconel 713C alloys. Above 800°C, however, ultimate tensile strength decreased rapidly with increasing temperature (lower than casted Inconel 713C). Based on the observation of fractography, initial crack was found to have started near the surface defects and propagated rapidly. The superior mechanical properties of MIMed Inconel 713C could be obtained by optimizing the MIM process parameters.
Objective: Pressure ulcers (PUs) are a serious problem in patients with multiple comorbidities and are associated with a longer duration of hospital stay and higher medical costs. The aetiology and rate of PU occurrence in South Korea remains unclear. Therefore, we aimed to determine the incidence, prevalence, mortality and common comorbidities of hospitalised patients with PUs in the South Korean healthcare system. Method: A 10-year cohort study using the healthcare insurance reimbursement claims from the South Korean National Health Insurance System database. Patients diagnosed with a PU on admission to hospital [ICD-10: L89 + procedure code] between January 2002 and December 2016 were included and their comorbidities evaluated. Patients <20 years of age and recurrent PU cases were excluded. Results: Incidence, prevalence, survival rate and risk factors related to survival rate of patients with PUs were determined. The study population in 2006 was 36,195,121 (all patients admitted to hospital that year), which changed yearly because of the inclusion of additional patients who met the study inclusion criteria, and removal of patients who had died during the year. Standardised PU incidence rate decreased from 17.1 in 2006 to 14.9 in 2015 per 10,000 people. Standardised PU prevalence also showed a slightly decreasing trend from 20.2 in 2006 to 18.9 in 2015 per 10,000 people. Conclusion: This findings of this 10-year study showed that incidence and prevalence of PUs markedly increased with age after the seventh decade. Incidence of PUs increased in patients with pneumonia, cerebral infarction, sepsis, femoral neck fracture and malignant neoplasm of the bronchus. Patients with femoral neck fracture and cerebral infarction showed a higher rate of survival than those with other high-risk comorbidities.
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