214 research outputs found
Rare case report of accidental intravenous injection of oral probiotic
Oral probiotics containing spores of Bacillus clausii are given to the patients who have undergone major surgery or are on long term antibiotic course, to restore intestinal microbial flora. We are reporting a rare case where the oral probiotic suspension was injected intravenously by mistake. We shall be discussing in detail the reactionary changes caused by erroneous injection of oral probiotics in the body, its effects, complications and treatment of the reactionary changes
Management of late presentation congenital heart disease
In many parts of the world, mostly low- and middle-income countries, timely diagnosis and repair of congenital heart diseases (CHDs) is not feasible for a variety of reasons. In these regions, economic growth has enabled the development of cardiac units that manage patients with CHD presenting later than would be ideal, often after the window for early stabilisation - transposition of the great arteries, coarctation of the aorta - or for lower-risk surgery in infancy - left-to-right shunts or cyanotic conditions. As a result, patients may have suffered organ dysfunction, manifest signs of pulmonary vascular disease, or the sequelae of profound cyanosis and polycythaemia. Late presentation poses unique clinical and ethical challenges in decision making regarding operability or surgical candidacy, surgical strategy, and perioperative intensive care management
Fabrication and machining performance of ceramic cutting tool based on the Al2O3-ZrO2-Cr2O3 compositions
This study presents the cutting tool development of zirconia toughened alumina (ZTA) with
chromia addition. The process used for its development is solid-state, in which the powders
of Alumina (Al2O3), Zirconia (ZrO2) and Chromia (Cr2O3) were processed by a ball mill, com�pacted under a Cold Isostatic Press (CIP) and sintered at a constant temperature of 1400 ◦C
with 9h soaking time. The initial study investigated the effect of Polyethylene glycol (PEG)
as a binder, CIP and hardness of Al2O3-ZrO2 mixtures. The percentage composition between
Al2O3 and ZrO2 was varied to choose the best for the highest mechanical performances
determined by the density, porosity and properties analysis. The cutting tool that possessed
the highest hardness and bending strength was selected the Al2O3-ZrO2 mixture was mixed
0.6 wt% Cr2O3 for machining trials within the cutting speed of 200–350m/min and constant
feed rate and depth of cut of 0.150mm/rev and 0.5mm, respectively. The results of the ZTA
mixed with Cr2O3 and combined with the ratio 80-20-0.6 wt% showed that the addition of
0.6 wt% PEG and a CIP pressure at 300 MPa and 60 s dwell time resulted maximum hardness
and bending strength of 71.03 HRc and 856.02 MPa, respectively. The fabricated cutting tool
was capable to reach 225 s tool life when machining AISI 1045 at a lower cutting speed of
200 m/min and higher feed rate of 0.150mm/rev
Effect of sintering temperature on density, hardness and tool wear for alumina-zirconia cutting tool
Combination of alumina (Al2O3) and zirconia (ZrO2) as cutting tool have been established
themselves as a dominant in ceramic category for dry machining. The mechanical properties
of Al2O3-ZrO2 cutting tool were critically dependent on its density and hardness, which
affected by the powder preparation and sintering processes. This paper present the effect of
sintering temperature on density, hardness and tool wear of Al2O3-ZrO2 cutting tool. Specific
composition of 80-90 wt% Al2O3 and 10-20 wt% ZrO2 powders were mixed and ball milled
for 12 hours. These powders then were compacted in the form of RNGN120600 designated
cutting tool by using manual hydraulic press before undergone secondary compaction by
Cold Isostatic Press. The compacted powders then were sintered from 1200oC to 1400oC at
constant 9 hours soaking time. For each sintered cutting tool, evaluation has been made based
on the density and hardness. By using AISI 1045 as a workpiece material, the wear
performance of the selected cutting tools were evaluated within 200-350 m/min cutting
speeds, 0.1 mm/rev feed rate and 0.5 mm depth of cut. The results shows that the sintering
temperature at 1400oC and 9 hours soaking time produced maximum relative density and
hardness for 90 wt% Al2O3 and 10 wt% ZrO2 at 94.17% and 63.4 HRC respectively. Cutting
tool contained with 80 wt% Al2O3 and 20 wt% ZrO2 contributed maximum relative density
of 97% and hardness of 70.07 HRC. Maximum tool life recorded was 156s at 200 m/min
cutting speed. Wear mechanisms of fabricated cutting tool dominated by the notch and flank
wear at the early stage of machining and formation built up edge at the end of machining
process
Comparison machining performance of Al2 O3 , ZTA and ZTA doped Cr2 O3 cutting tools on AISI 1045
This paper presents the comparison of machining performance for cutting tools that fabricated by pure alumina (Al2O3), Zirconia Toughened Alumina (ZTA) and Zirconia Toughened Alumina doped with Cr2O3 (ZTA Doped Cr2O3). Solid-state method was employed to prepare ceramic mixtures starting from 12 h ball milling with 40 rpm rotational speed. The green bodies were formed by 5 ton manual hydraulic press and 300 MPa Cold Isostatic Press (CIP) compaction pressure. The compacted powders then were sintered at 1400 °C and 9 h soaking time in the form of RNGN 120600 designated cutting tools. Properties assessment of the fabricated cutting tools were analysed based on hardness and density. The machining evaluation was performed by turning AISI 1045 with cutting speeds of 150–350 m min−1, feed rate of 0.125 mm/rev and depth of cut of 0.5 mm. The results show that maximum hardness recorded for ZTA Doped Cr2O3 with 13.73 GPa Vickers hardness and 3.82 g cm−3 density, followed by ZTA (12.75 GPa, 3.85 g cm−3) and pure Al2O3 (4.9 GPa, 3.76 g cm−3)In terms of machining performance, ZTA Doped Cr2O3 recorded highest tool life of 330-s with 57% improvement of tool life as compared to ZTA (210-s) and 200% improvement of pure Al2O3 (110-s). Dominant wear mechanisms for the fabricated cutting tool appeared to be notch wear, abrasive wear and chipping at the flank wear area
Effect of hydraulic pressure on hardness, density, tool wear and surface roughness in the fabrication of alumina based cutting tool
Cutting tools can be considered major industrial necessities as it
applied mostly to machine components. Development of self-fabricated cutting
tool can facilitate lower machining cost as long as the cutting tool can perform
effectively. This paper presents the effect of hydraulic pressure on density, hardness,
wear performance and surface roughness during fabrication of the alumina based
ceramic cutting tool. Specific raw of alumina powders were ball milled compacted
into green body using hydraulic press with different pressures of 6, 7, 8 and 9 tons.
These green bodies were sintered at 1700°C in 4 hours soaking time. Hardness
and density of sintered bodies were examined in order to correlate the effect of
hydraulic pressure on mechanical properties. The samples were further tested into
machining with AISI 1045 in order to evaluate their wear performances and surface
roughness. The results show that density and hardness increased as the hydraulic
pressure increased. The highest pressure of 9 tons demonstrated highest density
and hardness of 2.77 g/cm3
and 86.1 HRA respectively. The fabricated cutting tool
capable to cut the AISI 1045 steel with the minimum wear rate recorded at 0.0025
mm/s for 9 ton of pressured sample. In terms of failure modes, the cutting tool
suffered with abrasive wear and cracks at the edge of tool nose radius. Surface
roughness demonstrate minimum 1.24 µm for 7 ton of pressure, which considered
high for short time machining process. Overall, the self-fabricated cutting tool
capable to cut the steel without catastrophic failure which demonstrated promising
results to be improved in the future
Determinants of expression of SARS-CoV-2 entry-related genes in upper and lower airways
Peer reviewe
Performance of autonomous vehicles in mixed traffic under different demand conditions
Autonomous Vehicles (AVs) are considered one of the potential solutions to future urban mobility with several promised benefits regarding safety and traffic operation. Despite of expected benefits, these vehicles will take decades to have full market penetration and before that, AVs will co-exist with Conventional Vehicles (CVs), which may affect the performance of AVs owing to different driving logic than CVs. The aim of this study is to quantify the impacts of varying penetrations of AVs when introduced in mixed traffic conditions. The study employed simulation environment VISSIM to study the different scenarios based on the percentage of AVs in mixed traffic, category of AVs and varying demand levels. The findings show that at lower demand levels (1000 veh/hr and 2000 veh/hr), CVs and three categories of AVs produced similar results. However, cautious and normal AVs negatively affect traffic operations when the demand level is increased. At demand-3 (3000 veh/hr), the penetration rates of cautious AVs greater than 50% shows negative impact on performance. At demand-4 (4000 veh/hr), even a small proportion (25%) of cautious AVs can negatively affect performance, and a similar effect is observed for normal AVs with a penetration rate greater than 75%. For speed, the minimum reduction with the increase in demand is observed for aggressive AVs, followed by conventional vehicles, normal AVs and cautious AVs. It can be concluded that the aggressive AVs produced better delays, queue length, speed and conflicts than CVs, cautious AVs and normal AVs at the highest demand levels
Responses of haptoglobin and serum amyloid A in goats inoculated intradermally with C. pseudotuberculosis and mycolic acid extract immunogen
Haptoglobin (Hp) and Serum Amyloid A (SAA) are a group of blood proteins whose concentrations in animals can be influenced by infection, inflammation, surgical trauma or stress. Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), and Mycolic acid is a virulent factor extracted from C. pseudotuberculosis. There is a dearth of sufficient evidence on the clinical implication of MAs on the responses of Hp and SAA in goats. Therefore, this study was conducted to evaluate the potential effects of Mycolic acid (MAs) and C. pseudotuberculosis on the responses of Hp and SAA in female goats. A total of 12 healthy female goats was divided into three groups; A, B and C each comprising of 4 goats and managed for a period of three months. Group (A) was inoculated with 2 mL of sterile phosphate buffered saline (as a negative control group) intradermally, while group (B) and (C) were inoculated intradermally with 2 ml each of mycolic acid and 1 × 109 cfu of active C. pseudotuberculosis respectively. The result of the study showed that the Hp concentration in goats inoculated with C. pseudotuberculosis was significantly increased up to 7-fold (1.17 ± 0.17 ng/L) while MAs showed a 3-fold increased (0.83 ± 0.01 ng/L) compared with the control. Whereas SAA concentration in C. pseudotuberculosis and MAs groups showed a significant 3-fold (17.85 ± 0.91 pg/mL) and 2-fold (10.97 ± 0.71 pg/mL) increased compared with the control. This study concludes that inoculation of C. pseudotuberculosis and MAs have significant effects on Hp and SAA levels, which indicates that MAs could have a role in the pathogenesis of caseous lymphadenitis
Use of alcoholic beverages in VA medical centers
BACKGROUND: Benzodiazepines are the first-line choice for the treatment of alcohol withdrawal syndrome. However, several hospitals continue to provide alcoholic beverages through their formulary for the treatment of alcohol withdrawal. While there are data on the prevalence of this practice in academic medical centers, there are no data on the availability of alcoholic beverages at the formularies of the hospitals operated by the department of Veteran's Affairs. METHODS: In this study, we surveyed the Pharmacy managers at 112 Veterans' Affairs Medical Centers (VAMCs) to ascertain the availability of alcohol on the VAMC formularies, and presence or lack of a policy on the use of alcoholic beverages in their VA Medical Center. RESULTS: Of the pharmacy directors contacted, 81 responded. 8 did not allow their use, while 20 allowed their use. There was a lack of a consistent policy across the VA medical centers on availability and use of alcoholic beverages for the treatment of alcohol withdrawal syndrome. CONCLUSION: There is lack of uniform policy on the availability of alcoholic beverages across the VAMCs, which may create potential problems with difference in the standards of care
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