Comprehensive study of the effect of hot-dipping process parameters on Sn-Sb coating properties for α-brass substrate

This study's main purpose is to achieve an optimal hot-dip coating condition of Sn-Sb for an α-brass alloy. Therefore, the hot-dipping parameters, including pre-flux lubricants, immersion temperature, time, and withdrawal speed were investigated. ZnCl2 and SnCl2 were used as pre-flux bath additives. The temperature of the immersion bath was selected to be in the range of 250-300 °C. Also, the exposing time and withdrawal speed of the specimens during the hot-dipping process were in the range of 10-60 sec and 254-1524 mm/min, respectively. Visual inspection of the coating revealed that by using SnCl2 as a pre-flux additive, high-quality smooth coating is achieved. According to the AFM result, the initial roughness value of the substrate was 450 nm. The coating's roughness value with SnCl2 and SnCl2+ZnCl2 pre-fluxes were in the range of 300-500 and 700-900 nm, respectively. Therefore, ZnCl2 pre-flux is associated with a rougher surface. Corrosion test analysis revealed that both coating condition with different pre-fluxes leads to increasing corrosion resistance however better improvement in corrosion behavior is accomplished by smooth coating surface. The quantitative analysis of the polarization curve revealed that the corrosion rate of the smooth coating is decreased 7-12.5 times in comparison with the substrate. According to the SEM analysis, the predominant phases which were appeared at the interface of the coating and substrate were Cu3Sn and Cu6Sn5. SEM analysis revealed that the Cu3Sn intermetallic compound was this first phase, which was promoted near to the substrate vicinity during the hot-dipping process

The role of D-dimer in one year recurrence of venous thromboembolism after anticoagulation withdrawal following a first idiopathic deep vein thrombosis

Background: After discontinuing oral anticoagulant therapy (OAT), the recurrence of venous thromboembolism (VTE) is greatest in the 1st year and gradually diminishes. D-dimer assay was proposed to be eff ective in selecting patients with idiopathic DVT. Th e aim of this study was to determine the rate of VTE recurrence after discontinuing OAT according to the results of D-dimer. Materials and Methods: Th is prospective study was conducted in patients with a fi rst episode of symptomatic proximal deep vein thrombosis (DVT) who had received OAT for at least 3 months. Patients were re-evaluated at 1st, 6th and 12th months of their follow-up. At the fi rst (T0) and 30-day (T1) visits, venous blood samples were taken for D-dimer test. At each follow-up visit, we examined patients for clinical symptoms or signs of recurrent VTE, bleeding, postthrombotic manifestations, adherence to treatment, and concomitant analgesic or antiinflammatory therapy. Th e endpoint outcomes were VTE recurrence and complete of this survey follow-ups. Results: A total of 68 eligible patients was enrolled. Four patients (two patients need to use long-term oral anticoagulation, and two patients lost their fi rst follow-up) were excluded. At T0, D-dimer and compression ultrasonongraphy (CUS) was normal in 28 patients (44%). Moreover, 36 patients had abnormal D-dimer but normal CUS. A follow-up of 12 months was available in 44 patients. During the follow-up, three recurrent events were recorded. All Recurrent events were ipsilateral DVT. Among these index cases, all had an abnormal D-dimer at either T0 and/or T1. Th e recurrence rate was higher in males than in females (8.6% vs. 2.2%, P = 0.04) with an abnormal D-dimer at T0 and/or T1 with a multivariate hazard ratio of 2.1 (95% confi dence intervals [CI]: 1.2-5.2; P = 0.02). Patients older than 65 years had a higher rate of events than younger and hazard ratio was about 3.8 (95% CI: 2.1-4.2; P = 0.02). Patients with recurrences had higher mean D-dimer at both T0 and T1 when compared with those without recurrences, but the diff erence was signifi cant only for D-dimer at T1 (P = 0.03). During the follow-up, two patients died (3%). Conclusion: Within 12 months followup, the risk of recurrence with an abnormal D-dimer, either during or at 1-month after discontinuing OAT, was 4.6% which is much lower to the annual risk of recurrence in most studies with idiopathic and provoked VTE. D-dimer has an acceptable prognostic value in detecting recurrence of idiopathic VTE before discontinuing the anticoagulant therapy

The prediction role of D-dimer in recurrence of venous thromboembolism 1-year after anticoagulation discontinuing following idiopathic deep vein thrombosis

Background: After discontinuing oral anticoagulant therapy (OAT), the recurrence of venous thromboembolism (VTE) is greatest in the 1st year and gradually diminishes. D-dimer assay was proposed to be effective in selecting patients with idiopathic DVT. The aim of this study was to determine the rate of VTE recurrence after discontinuing OAT according to the results of D-dimer. Materials and Methods: This prospective study was conducted in patients with a first episode of symptomatic proximal deep vein thrombosis (DVT) who had received OAT for at least 3 months. Patients were re-evaluated at 1st, 6th and 12th months of their follow-up. At the first (T0) and 30-day (T1) visits, venous blood samples were taken for D-dimer test. At each follow-up visit, we examined patients for clinical symptoms or signs of recurrent VTE, bleeding, postthrombotic manifestations, adherence to treatment, and concomitant analgesic or antiinflammatory therapy. The endpoint outcomes were VTE recurrence and complete of this survey follow-ups. Results: A total of 68 eligible patients was enrolled. Four patients (two patients need to use long-term oral anticoagulation, and two patients lost their first follow-up) were excluded. At T0, D-dimer and compression ultrasonongraphy (CUS) was normal in 28 patients (44%). Moreover, 36 patients had abnormal D-dimer but normal CUS. A follow-up of 12 months was available in 44 patients. During the follow-up, three recurrent events were recorded. All Recurrent events were ipsilateral DVT. Among these index cases, all had an abnormal D-dimer at either T0 and/or T1. The recurrence rate was higher in males than in females (8.6% vs. 2.2%, P = 0.04) with an abnormal D-dimer at T0 and/or T1 with a multivariate hazard ratio of 2.1 (95% confidence intervals [CI]: 1.2-5.2; P = 0.02). Patients older than 65 years had a higher rate of events than younger and hazard ratio was about 3.8 (95% CI: 2.1-4.2; P = 0.02). Patients with recurrences had higher mean D-dimer at both T0 and T1 when compared with those without recurrences, but the difference was significant only for D-dimer at T1 (P = 0.03). During the follow-up, two patients died (3%). Conclusion: Within 12 months follow-up, the risk of recurrence with an abnormal D-dimer, either during or at 1-month after discontinuing OAT, was 4.6% which is much lower to the annual risk of recurrence in most studies with idiopathic and provoked VTE. D-dimer has an acceptable prognostic value in detecting recurrence of idiopathic VTE before discontinuing the anticoagulant therapy

Comparing three clinical prediction rules for primarily predicting the 30-day mortality of patients with pulmonary embolism: The “Simplified Revised Geneva Score,” the “Original PESI,” and the “Simplified PESI”

Background: Patients with suspected pulmonary embolism (PE) should be evaluated for the clinical probability of PE using an applicable risk score. The Geneva prognostic score, the PE Severity Index (PESI), and its simplified version (sPESI) are well-known clinical prognostic scores for PE. The purpose of this study was to analyze these clinical scores as prognostic tools. Materials and Methods: A historical cohort study was conducted on patients with acute PE in Al-Zahra Teaching Hospital, Isfahan, Iran, from June 2013 to August 2014. To compare survival in the 1-month follow-up and factor-analyze mortality from the survival graph, Kaplan–Meier, and log-rank logistic regression were applied. Results: Two hundred and twenty four patients were assigned to two “low risk” and “high risk” groups using the three versions of “Simplified PESI, Original PESI, and Simplified Geneva.” They were followed for a period of 1 month after admission. The overall mortality rate within 1 month from diagnosis was about 24% (95% confidence interval, 21.4–27.2). The mortality rate of low risk PE patients was about 4% in the PESI, 17% in the Geneva, and <1% in the simplified PESI scales (P < 0.005). The mortality rate among high risk patients was 33%, 33.5%, and 27.5%, respectively. Conclusions: Among patients with acute PE, the simplified PESI model was able to accurately predict mortality rate for low risk patients. Among high risk patients, however, the difference between the three models in predicting prognosis was not significant