Five referral hospitals, South Korea.
To assess epidemiological changes in TB before and during the COVID-19 pandemic.
This was a multicentre cohort study of 3,969 patients diagnosed with TB.
We ...analysed 3,453 patients diagnosed with TB prior to the COVID-19 pandemic (January 2016-February 2020) and 516 during the pandemic (March-November 2020). During the pandemic, the number of patients visits declined by 15% from the previous 4-year average, and the number of patients diagnosed with TB decreased by 17%. Patients diagnosed during the pandemic were older than those diagnosed before the pandemic (mean age, 60.2 vs. 56.6 years,
< 0.001). The proportion of patients to have primary TB at a younger age (births after 1980) among those diagnosed with TB was significantly lower during the pandemic than before (17.8% in 2020 vs. 23.5% in 2016, 24.0% in 2017, 22.5% in 2018, 23.5% in 2019;
= 0.005).
The COVID-19 pandemic resulted in a reduction in the number of visits to respiratory departments, leading to fewer patients being diagnosed with TB. However, our results suggest that universal personal preventive measures help to suppress TB transmission in regions with intermediate TB burden.
The present is a study of the solidification and microstructure of Fe–28.2%Cr–3.8%B–1.5%Si–1.5%Mn (wt.%) alloy deposited onto a 1020 plain carbon steel substrate using the controlled short-circuit ...metal inert gas welding process. The as-solidified alloy was a metal matrix composite with a hypereutectic microstructure. Thermodynamic calculation based on the Scheil–Gulliver model showed that a primary (Cr,Fe)2B phase formed first during solidification, followed by an eutectic formation of the (Cr,Fe)2B phase and a body-centered cubic Fe-based solid solution matrix, which contained Cr, Mn and Si. Microstructure analysis confirmed the formation of these phases and showed that the shape of the (Cr,Fe)2B phase was irregular plate. As the welding heat input increased, the weld dilution increased and thus the volume fraction of the (Cr,Fe)2B plates decreased while other microstructural characteristics were similar.
•We deposit Fe–Cr–B-based alloy onto plain carbon steel using the CSC-MIG process.•We model the solidification behavior using thermodynamic calculation.•As deposited alloy consists of (Cr,Fe)2B plates embedded in Fe-based matrix.•We study the effect of the welding heat input on the microstructure.
Abstract
Energy is a major cost component in diets for poultry. We hypothesized that the supplementation of emulsifier blends in broiler diets may contribute to the efficient utilization of energy ...and in increasing fat digestibility, thereby improving performance. To test our hypothesis, an experiment was conducted to evaluate the effect of a blend of emulsifiers on growth performance, nutrient digestibility, serum lipid profiles, and meat quality of broilers. A total of 768 1-d-old Ross 308 male broiler chicks with an average initial body weight of 45.55 ± 0.34 g were used in a 35 days feeding trial. Broilers were sorted into 4 treatments, 12 replications per treatment, and 16 birds per pen. Dietary treatments consisted of corn-soybean meal based basal diet and the basal diet supplemented with 0.05%, 0.075%, and 0.10% emulsifier. As a result of this study, the inclusion of 0.05%, 0.075%, and 0.10% emulsifier blends (sodium stearoyl-2-lactylate (SSL) and Tween 20) in the basal diet linearly increased (P = 0.0001) body weight gain (BWG) and improved feed conversion ratio (FCR) (linear effect P = 0.0001) on d 7 to 21, d 21 to 35 as well as overall. Broilers fed with different levels of emulsifier blends also showed a linear increment (P < 0.05) in dry matter (DM) and fat digestibility. A trend of linear reduction (P = 0.051) in low density lipoprotein (LDL) in the serum of broilers fed emulsifier blend was observed. The lightness value of breast muscle color linearly increased (P = 0.001), the redness and yellowness values tended to increase (P = 0.072 and P = 0.094 respectively), and the water holding capacity (WHC) showed trends in reduction (P = 0.078) with an increase in the level of emulsifier blends. With regards to relative organ weight, spleen weight was linearly (P = 0.001) reduced with the increase in the supplemental levels of emulsifier blends. A positive correlation between emulsifier content in the diet and BWG, DM and fat digestibility, and breast muscle color indices, were also observed. In conclusion, emulsifier blend supplementation positively influenced growth performance and nutrient digestibility in broiler chickens.
The present work studied the formation of new phases by adding alloying additions (Ca, Sr, and Ce) in AZ31 alloy at micro-levels (approximately 0.2
wt.% per element). Quantitative electron probe ...micro-analysis (EPMA) was used to identify the compositions of these phases; a comparison in the morphology and distribution of an identical phase in different alloy systems was made; and the thermodynamic software of FactSage™ was utilized to calculate the possible intermetallic phases during solidification. The results of EPMA showed the existence of phases other than Mg
17(Al, Zn)
12 and Al
8Mn
5 in AZ31 alloy, namely: Al
2Ca, Al
2Sr, Al
11Ce
3, Al
8CeMn
4, and Al
2(Ca Sr); and these new phases were thermally stable at 450
°C for 10
h. The morphology and distribution of second phases in different alloy systems were self-consistent. These phases were well predicted by FactSage™ with recent light alloy database.
Rapid solidification of silver-rich Ag–Cu–Zr alloys Castellero, A.; Kang, D.H.; Jung, I.-H. ...
Journal of alloys and compounds,
09/2012, Letnik:
536, Številka:
SUPPL.1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
► Ag-rich amorphous/crystalline composites were obtained by liquid phase separation. ► Amorphisation is strongly inhibited when increasing the Ag content. ► Mechanical properties of the composites ...are mainly dominated by the amorphous matrix.
In this work we explored the possibility of obtaining amorphous/crystalline composites in the Ag-rich side of the Ag–Cu–Zr ternary system exploiting the presence of a miscibility gap in the liquid. Four alloys with nominal composition (at.%) Ag75Cu11Zr14 (alloy A), Ag73Cu17Zr10 (alloy B), Ag47.5Cu22.5Zr30 (alloy C), Ag47.5Cu30Zr22.5 (alloy D) were investigated. The effect of the cooling rate and the composition on phase selection and microstructures was evaluated by comparing slowly cooled master ingots and rapidly quenched ribbons. Evidence of the liquid miscibility gap was observed only in alloys B and D, either in the master ingots and the ribbons. After rapid solidification, partial amorphisation was achieved for alloys C and D, where precipitates of the Ag-rich solid solution, showing various sizes, are dispersed in the amorphous matrix. A significant increase in hardness was achieved in the case of partially amorphous ribbons of alloys C and D (442 HV and 533 HV, respectively). Experimental results are discussed on the basis of the recently reassessed ternary Ag–Cu–Zr phase diagram.
The effect of atmospheric pressure plasma treatment of polypropylene (PP) on the peel strength and shear strength between PP and aluminum plates was studied. The optimal treatment number was ...determined by measuring the changes in the contact angle, paint adhesion strength, and Scotch tape peel strength as a function of treatment number. FTIR and AFM analyses were conducted to determine the chemical and physical changes on the surface of the PP due to the atmospheric pressure plasma treatment. T-peel and SLS tests were performed using untreated PP/aluminum and plasma-treated PP/aluminum specimens to determine the effect of treatment on the peel strength and shear strength of PP/aluminum composites. The results showed that eight plasma treatments were optimal, and the contact angle was reduced from ∼91° to ∼53°. The results also showed that peel and shear strengths improved by ∼42% and ∼44%, respectively, after eight times of treatment. The improved bonding strength was attributed to the increased surface roughness and newly created hydrophilic functional group (CO) on the polypropylene surface caused by the atmospheric pressure plasma treatment.
The effects of fiber alignment and direction of mechanical stimuli on the ECM generation of human ligament fibroblast (HLF) were assessed. The nanofiber matrix was fabricated using electrospinning ...technique. To align the nanofibers, a rotating target was used. The HLFs on the aligned nanofibers were spindle-shaped and oriented in the direction of the nanofibers. The degree of ECM production was evaluated by comparing the amount of collagen on aligned and randomly oriented structures. Significantly more collagen was synthesized on aligned nanofiber sheets, although the proliferation did not differ significantly. This suggests that the spindle-shape observable in intact ligaments is preferable in producing ECM. To evaluate the effect of strain direction on the ECM production, HLFs were seeded on parallel aligned, vertically aligned to the strain direction, and randomly oriented nanofiber sheets attached to Flexcell
® plates. After a 48-h culture, 5% uniaxial strain was applied for 24
h at a frequency of 12 cycles/min. The amounts of collagen produced were measured 2 days after halting the strain application. The HLFs were more sensitive to strain in the longitudinal direction. In conclusion, the aligned nanofiber scaffold used in this study constitutes a promising base material for tissue-engineered ligament in that it provides more preferable biomimetic structure, along with proper mechanical environment.
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