The hot deformation behavior of an IN718 superalloy was studied by isothermal compression tests under the deformation temperature range of 950–1100°C and strain rate range of 0.001–1s−1 up to true ...strains of 0.05, 0.2, 0.4 and 0.7. Electron backscattered diffraction (EBSD) technique was employed to investigate systematically the effects of strain, strain rate and deformation temperature on the subgrain structures, local and cumulative misorientations and twinning phenomena. The results showed that the occurrence of dynamic recrystallization (DRX) is promoted by increasing strain and deformation temperature and decreasing strain rate. The microstructural changes showed that discontinuous dynamic recrystallization (DDRX), characterized by grain boundary bulging, is the dominant nucleation mechanism in the early stages of deformation in which DRX nucleation occurs by twining behind the bulged areas. Twin boundaries of nuclei lost their ∑3 character with further deformation. However, many simple and multiple twins can be also regenerated during the growth of grains. The results showed that continuous dynamic recrystallization (CDRX) is promoted at higher strains and large strain rates, and lower temperatures, indicating that under certain conditions both DDRX and CDRX can occur simultaneously during the hot deformation of IN718.
Hot deformation behavior of a medium carbon microalloyed steel Mirzadeh, H.; Cabrera, J.M.; Prado, J.M. ...
Materials science & engineering. A, Structural materials : properties, microstructure and processing,
04/2011, Letnik:
528, Številka:
10
Journal Article
Recenzirano
► Hot compression test under a wide range of temperature and strain rate. ► A step-by-step procedure for data analysis in hot deformation. ► Critical discussion on the application of constitutive ...equations.
The hot deformation behavior of a medium carbon microalloyed steel was studied using the hot compression flow curves corresponding to the temperature range of 850–1150
°C under strain rates from 0.0001 to 3
s
−1. A step-by-step procedure for data analysis in hot deformation was also given. The work hardening rate versus stress curves were used to reveal if dynamic recrystallization (DRX) occurred. The application of constitutive equations to determine the hot working constants of this material was critically discussed. Furthermore, the effect of Zener–Hollomon parameter (
Z) on the characteristic points of flow curves was studied using the power law relation. The deformation activation energy of this steel was determined as 394
kJ/mol and the normalized critical stress and strain for initiation of DRX were found to be 0.89 and 0.62, respectively. Some behaviors were also compared to other steels.
Aims/hypothesis We analysed the factors that determine the outcomes of surgical treatment of osteomyelitis of the foot in diabetic patients given early surgical treatment within 12 h of admission and ...treated with prioritisation of foot-sparing surgery and avoidance of amputation. Methods A consecutive series of 185 diabetic patients with foot osteomyelitis and histopathological confirmation of bone involvement were followed until healing, amputation or death. Results Probing to bone was positive in 175 cases (94.5%) and radiological signs of osteomyelitis were found in 157 cases (84.8%). Staphylococcus aureus was the organism isolated in the majority of cultures (51.3%), and in 35 cases (36.8%) it proved to be methicillin-resistant. The surgical treatment performed included 91 conservative surgical procedures, which were defined as those where no amputation of any part of the foot was undertaken (49.1%). A total of 94 patients received some degree of amputation, consisting of 79 foot-level (minor) amputations (42.4%) and 15 major amputations (8%). Five patients died during the perioperative period (2.7%). Histopathological analysis revealed 94 cases (50.8%) of acute osteomyelitis, 43 cases (23.2%) of chronic osteomyelitis, 45 cases (24.3%) of acute exacerbation of chronic osteomyelitis and three remaining cases (1.6%) designated as 'other'. The risks of failure in the case of conservative surgery were exposed bone, the presence of ischaemia and necrotising soft tissue infection. Conclusions/interpretation Conservative surgery without local or high-level amputation is successful in almost half of the cases of diabetic foot osteomyelitis. Prospective trials should be undertaken to determine the relative roles of conservative surgery versus other approaches.
The lymphopenia exhibited in patients with COVID-19 has been associated with a worse prognosis in the development of the disease.
To understand the factors associated with a worse evolution of ...COVID-19, we analyzed comorbidities, indicators of inflammation such as CRP and the ratio of neutrophils/lymphocytes, as well as the count of blood cells with T-lymphocyte subtypes in 172 hospitalized patients with COVID-19 pneumonia. Patients were grouped according to their needs for mechanical ventilation (ICU care) or not.
Within the comorbidities studied, obesity was the only associated with greater severity and ICU admission. Both the percentage and the absolute number of neutrophils were higher in patients needing ICU care than non-ICU patients, whereas absolute lymphocyte count, and especially the percentage of lymphocytes, presented a deep decline in critical patients. There was no difference between the two groups of patients for CD4 T-lymphocytes, neither in percentage of lymphocyte nor in absolute number, however for CD8 T-cells the differences were significant for both parameters which were in decline in ICU patients. There was a firm correlation between the highest values of inflammation indicators with the decrease in percentage of CD8 T-lymphocytes. This effect was not seen with CD4 cells.
Obesity together with lymphopenia, especially whether preferentially affects to CD8 T- lymphocytes, are factors that can predict a poor prognosis in patients with COVID-19.
•Among the comorbidities studied, only obesity is associated with a worse prognosis in patients with COVID-19.•The number of lymphocytes in blood, especially expressed as a percentage, is the main analytic factor that is associated with severity in COVID-19.•COVID-19 patients with ICU care have a selective decrease in blood CD8 cells that does not happen with CD4 cells.•There was a correlation in COVID-19 patients between inflammation indicators with the decrease in percentage of CD8 T-lymphocytes.
The misuse of antibiotics has been related to increased morbidity, mortality and bacterial resistance. The development of antimicrobial stewardship programmes (ASPs) has been encouraged by scientific ...societies as an essential measure. An educational, institutionally supported ASP was developed in our tertiary-care centre. Local guidelines on the management of infectious syndromes were created. Antimicrobial prescriptions were chosen arbitrarily weekly and counselling interviews by expert clinicians were carried out, using a paedagogic, non-restrictive methodology. Satisfaction with the interview was assessed using anonymous questionnaires. The appropriateness of antimicrobial prescriptions as well as consumption was assessed prospectively throughout the year. Feedback regarding the correct use of treatments was communicated to each participating department periodically. The improvement in antimicrobial prescription was included among the annual objectives linked to economic incentives in every department. A total of 1206 counselling interviews were carried out during the first year. Fifty-three per cent of antimicrobial prescriptions (176/332) were inappropriate when the programme started. The rate of inappropriate prescriptions continuously declined to 26.4% (107/405) in the fourth trimester (p <0.001; RR = 0.38; 95% CI, 0.23–0.43). Antimicrobial consumption decreased from 1150 defined daily doses (DDDs) per 1000 occupied bed-days in the first trimester to 852 DDDs in the fourth, reflecting a reduction in antimicrobial expenditures of 42%. A total of 352 satisfaction questionnaires were received and 98% described the advice as positive. In conclusion, the implementation of an education-based ASP achieved a significant improvement in all antimicrobial prescriptions in the centre and a reduction in antimicrobial consumption, even when no restrictive measures were implemented. The programme was highly accepted by all prescribers.
When steroids, such as pregnenolone, progesterone and oestrogen, are synthesised de novo in neural tissues, they are more specifically referred to as neurosteroids. These neurosteroids bind specific ...receptors to promote essential brain functions. Pregnenolone supports cognition and protects mouse hippocampal cells against glutamate and amyloid peptide‐induced cell death. Progesterone promotes myelination, spinogenesis, synaptogenesis, neuronal survival and dendritic growth. Allopregnanolone increases hippocampal neurogenesis, neuronal survival and cognitive functions. Oestrogens, such as oestradiol, regulate synaptic plasticity, reproductive behaviour, aggressive behaviour and learning. In addition, neurosteroids are neuroprotective in animal models of Alzheimer's disease, Parkinson's disease, brain injury and ageing. Using in situ hybridisation and/or immunohistochemistry, steroidogenic enzymes, including cytochrome P450 side‐chain cleavage, 3β‐hydroxysteroid dehydrogenase/Δ5‐Δ4 isomerase, cytochrome P450arom, steroid 5α‐reductase and 3α‐hydroxysteroid dehydrogenase, have been detected in numerous brain regions, including the hippocampus, hypothalamus and cerebral cortex. In the present review, we summarise some of the studies related to the synthesis and function of oestrogens and progestagens in the central nervous system.
Purpose
The aim of this paper is to evaluate to the safety, feasibility and efficacy of a novel treatment for transsphincteric cryptoglandular fistula: injection of autologous plasma rich in growth ...factors (PRGF) into the fistula tract accompanied by sealing using a fibrin plug created from the activated platelet-poor fraction of the same plasma.
Method
This article is a prospective, phase II clinical trial. The procedure was externally audited. Thirty-six patients diagnosed with transsphincteric fistula-in-ano were included. All patients underwent follow-up examinations at 1 week and again at 3, 6 and 12 months after discharge. Main outcome measures safety (number of adverse events), feasibility and effectiveness of the treatment.
Results
A total of 36 patients received the study treatment, with the procedure found to be feasible in all patients. A total of seven adverse events (AE) related to the injected product or surgical procedure were identified in 4 of 36 patients. At the end of the follow-up period (12 months), 33.3% of patients (12/36) had achieved complete fistula healing and 11.1% of patients (4/36) had achieved partial healing. In total, this amounted to 44.4% of patients (16/36) being asymptomatic at final follow-up. In successfully healed patients, a gradual reduction in pain was observed, as measured using a Visual Analog Scale (VAS) (p = 0.0278). Compared to baseline, a significant improvement in Wexner score was seen in patients achieving total or partial healing of the fistula (p = 0.0195).
Conclusions
The study treatment was safe and feasible, with apparently modest efficacy rates. Continence and pain improvement following treatment may be considered predictive factors for healing.
The influence of initial microstructure on discontinuous dynamic recrystallization (DDRX) has been investigated by using high purity and ultra high purity austenitic stainless steels with various ...initial grain sizes. After uniaxial compression tests at constant strain rates and various temperatures, the steady state microstructure or the state corresponding to the maximum strain (ε=1) attained in the test was analyzed by scanning electron microscopy aided with automated electron back scattering diffraction. Recrystallized grain size drec and twin boundary fraction fTB measurements were carried out. The mechanical behavior was also investigated by comparing experimental stress–strain curves with various initial grain sizes. DDRX kinetics was described by the classical Avrami equation. It was concluded that larger initial grain sizes promoted a delay in the DDRX onset in the two alloys. It was also observed that the softening process progressed faster for smaller initial grain sizes. The effect of initial grain size is larger in the HP material and becomes more pronounced at low temperature.
Aim
To assess clinical healing in patients with perianal Crohn’s disease with local intrafistular injection of autologous platelet-rich plasma.
Method
The pilot study was conducted at a single centre ...between January 2013 and December 2015. Autologous platelet-rich plasma was prepared in platelet-rich and platelet-poor fractions for local intrafistular injection in patients with proven, established perianal Crohn’s disease. Patients were permitted biological therapies, and the Perianal Crohn’s Disease Activity Index was recorded. Patients were followed for 48 weeks for clinical signs of healing (complete, partial or non-healing), monitoring fistula drainage, closure and epithelialization.
Results
The study included 29 patients (19 males; mean age 38 ± 12.8 years) with four exclusions in the operating room because surgery was not indicated and four lost to follow-up. Five adverse events were recorded, with two requiring the drainage of abscess collections. Of the 21 patients assessable at 24 weeks, there was complete healing, partial healing and non-healing in 7 (33.3%), 8 (38.1%) and 6 (28.6%) patients, respectively. By 48 weeks, there was complete healing, partial healing and non-healing in 6 (40%), 6 (40%) and 3 (20%) patients, respectively, with a reduction in the number of visible external fistula openings at both time points (
P
= 0.021). By the end of the study, there was a higher trend of healing if biological therapies were continued (85.7% with biologics
vs.
75% without,
P
= 0.527), but there were no statistically significant differences and no differences in the Perianal Crohn’s Disease Activity Index.
Conclusion
Autologous platelet-rich plasma is safe in patients with perianal Crohn’s disease, with an acceptable healing rate over a medium-term follow-up, particularly if biological therapies are used concomitantly.
The role of dietary patterns in the prevention of unipolar depression has been analyzed in several epidemiological studies. The primary aims of this study are to determine the effectiveness of an ...extra-olive oil-enriched Mediterranean diet in reducing the recurrence of depression and improving the symptoms of this condition.
Multicenter, two-arm, parallel-group clinical trial. Arm 1, extra-virgin olive oil Mediterranean diet; Arm 2, control group without nutritional intervention. Dieticians are in charge of the nutritional intervention and regular contact with the participants. Contacts are made through our web platform ( https://predidep.es/participantes/ ) or by phone. Recurrence of depression is assessed by psychiatrists and clinical psychologists through clinical evaluations (semi-structured clinical interviews: Spanish SCID-I). Depressive symptoms are assessed with the Beck Depression Inventory. Information on quality of life, level of physical activity, dietary habits, and blood, urine and stool samples are collected after the subject has agreed to participate in the study and once a year.
To the best of our knowledge, the PREDI-DEP trial is the first ongoing randomized clinical trial designed to assess the role of the Mediterranean diet in the prevention of recurrent depression. It could be a cost-effective approach to avoid recurrence and improve the quality of life of these patients.
The study has been prospectively registered in the U.S. National Library of Medicine ( https://clinicaltrials.gov ) with NCT number: NCT03081065.
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