Thermal Stability, Adsorption and Rheological Behaviors of Sulfonated Polyacrylamide/Chromium Triacetate/Laponite Nanocomposite Weak Gels

Alvand Ehsan,Aalaie Jamal,Hemmati Mahmood,Sajjadian Vali Ahmad 한국고분자학회 2017 Macromolecular Research Vol.25 No.1

The objective of the present study is to improve the behavior of sulfonated polyacrylamide (SPA) by adding Laponite and/or chromium(III) with a focus on enhanced oil recovery applications. The resultant systems are weak nanocomposite hydrogels which are subjected to rheological, thermal stability and adsorption tests. The interactions between ingredients of the hydrogel are investigated by Fourier transform infrared (FTIR) spectroscopy. In addition, dispersion of Laponite nanoparticles in hydrogel is confirmed by transmission electron microscopy (TEM). The thermal stability is determined by measuring the loss of viscosity after an aging cycle. The adsorption tests are performed on calcite and evaluated using thermo gravimetric analysis. FTIR spectra confirmed the interaction of Laponite and Cr3+ with SPA. TEM micrograph showed an approximately uniform dispersion of Laponite in the crosslinked SPA/Cr3+/Laponite system. The viscoelastic behaviors of the systems improved with the addition of either Laponite or chromium(III). The sulfonated polyacrylamide/chromium(III)/Laponite system slightly loses its viscosifying power when subjected to harsh conditions of themo-chemical aging process. The adsorption behavior of the systems improved with Laponite concentration while the presence of chromium(III) weakened the adsorption. Therefore the introduced polymeric systems of the present study may be a potential option for enhanced oil recovery applications in hostile conditions.

Colloidal dispersion gels based on sulfonated polyacrylamide and chromium triacetate for harsh-environment

Jamal Aalaie,Ehsan Alvand,Mahmood Hemmati,Vali Ahmad Sajjadian 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.6

The aim of this study was to outline the preparation of colloidal dispersion gels (CDGs) based on sulfonated polyacrylamide (SPA) and chromium triacetate and investigating their stability in harsh conditions. The effect of crosslinker, polymer concentration, salinity, and gelation time and temperature on the formation, rheological behavior and size distribution of CDGs and also their thermo-chemical stabilities were investigated. It was found that the shear viscosity and size of CDGs decreased with increasing of preparation time. Dynamic light scattering and scanning electron microscopy evaluations showed that the size of CDGs particles decreased with increasing of the Cr3+ concentration. In addition, SPA solution had yield stress, while CDGs did not. The elevation of temperature inhibits while the salinity does not disturb the formation of CDGs. In the systems with lower polymer concentration, CDGs were formed. Conversely, in the systems with higher polymer concentration, bulk gels were formed. After aging, CDG sample had a minimal viscosity loss, indicating its exceptional thermo-chemical stability.

Estimating the Survival of Patients With Lung Cancer: What Is the Best Statistical Model?

Abedi, Siavosh,Janbabaei, Ghasem,Afshari, Mahdi,Moosazadeh, Mahmood,Alashti, Masoumeh Rashidi,Hedayatizadeh-Omran, Akbar,Alizadeh-Navaei, Reza,Abedini, Ehsan The Korean Society for Preventive Medicine 2019 예방의학회지 Vol.52 No.2

Objectives: Investigating the survival of patients with cancer is vitally necessary for controlling the disease and for assessing treatment methods. This study aimed to compare various statistical models of survival and to determine the survival rate and its related factors among patients suffering from lung cancer. Methods: In this retrospective cohort, the cumulative survival rate, median survival time, and factors associated with the survival of lung cancer patients were estimated using Cox, Weibull, exponential, and Gompertz regression models. Kaplan-Meier tables and the log-rank test were also used to analyze the survival of patients in different subgroups. Results: Of 102 patients with lung cancer, 74.5% were male. During the follow-up period, 80.4% died. The incidence rate of death among patients was estimated as 3.9 (95% confidence [CI], 3.1 to 4.8) per 100 person-months. The 5-year survival rate for all patients, males, females, patients with non-small cell lung carcinoma (NSCLC), and patients with small cell lung carcinoma (SCLC) was 17%, 13%, 29%, 21%, and 0%, respectively. The median survival time for all patients, males, females, those with NSCLC, and those with SCLC was 12.7 months, 12.0 months, 16.0 months, 16.0 months, and 6.0 months, respectively. Multivariate analyses indicated that the hazard ratios (95% CIs) for male sex, age, and SCLC were 0.56 (0.33 to 0.93), 1.03 (1.01 to 1.05), and 2.91 (1.71 to 4.95), respectively. Conclusions: Our results showed that the exponential model was the most precise. This model identified age, sex, and type of cancer as factors that predicted survival in patients with lung cancer.

The Effect of 12 Weeks Aerobic, Resistance, and Combined Exercises on Omentin-1 Levels and Insulin Resistance among Type 2 Diabetic Middle-Aged Women

Zeinab AminiLari,Mohammad Fararouei,Sasan Amanat,Ehsan Sinaei,Safa Dianatinasab,Mahmood AminiLari,Nima Daneshi,Mostafa Dianatinasab 대한당뇨병학회 2017 Diabetes and Metabolism Journal Vol.41 No.3

Background: Recent studies have shown that omentin-1 derived from adipokines can affect physiological regulations and some metabolic dis-eases such as type 2 diabetes mellitus (T2DM). Methods: The purpose of this study was to examine the impact of 12 weeks of aerobic (cycle ergometer), resistance, and combined exercises on omentin-1 level, glucose and insulin resistance indices in overweight middle age women with T2DM. In this study, 60 overweight middle age diabetic women were selected using simple random sampling and they were assigned to three groups of aerobic exercise (n=12), resistant exercise (n=12) and combined exercise (n=13), and one control group (n=15). Exercises were done in a three times per week sessions for a total of 12 weeks. Blood samples were collected before each exercise session and 24 hours after of the last session. Results: Present study showed that fasting blood sugar decreased significantly in all intervention groups, while homeostasis model assessment of insulin resistance (HOMA-IR) decreased only in the aerobic and combined exercises groups. Furthermore, there was a significant increase in the omentin-1 level only in the combined exercise group. Conclusion: Compared to aerobic and resistance exercises, 12 weeks of combined exercise was more efficient in improving HOMA-IR and increasing serum omentin-1 among women with T2DM.

Estimating the Survival of Patients With Lung Cancer: What Is the Best Statistical Model?

Siavosh Abedi,Ghasem Janbabaei,Mahdi Afshari,Mahmood Moosazadeh,Masoumeh Rashidi Alashti,Akbar Hedayatizadeh-Omran,Reza Alizadeh-Navaei,Ehsan Abedini 대한예방의학회 2019 Journal of Preventive Medicine and Public Health Vol.52 No.2

Objectives: Investigating the survival of patients with cancer is vitally necessary for controlling the disease and for assessing treatment methods. This study aimed to compare various statistical models of survival and to determine the survival rate and its related factors among patients suffering from lung cancer. Methods: In this retrospective cohort, the cumulative survival rate, median survival time, and factors associated with the survival of lung cancer patients were estimated using Cox, Weibull, exponential, and Gompertz regression models. Kaplan-Meier tables and the log-rank test were also used to analyze the survival of patients in different subgroups. Results: Of 102 patients with lung cancer, 74.5% were male. During the follow-up period, 80.4% died. The incidence rate of death among patients was estimated as 3.9 (95% confidence [CI], 3.1 to 4.8) per 100 person-months. The 5-year survival rate for all patients, males, females, patients with non-small cell lung carcinoma (NSCLC), and patients with small cell lung carcinoma (SCLC) was 17%, 13%, 29%, 21%, and 0%, respectively. The median survival time for all patients, males, females, those with NSCLC, and those with SCLC was 12.7 months, 12.0 months, 16.0 months, 16.0 months, and 6.0 months, respectively. Multivariate analyses indicated that the hazard ratios (95% CIs) for male sex, age, and SCLC were 0.56 (0.33 to 0.93), 1.03 (1.01 to 1.05), and 2.91 (1.71 to 4.95), respectively. Conclusions: Our results showed that the exponential model was the most precise. This model identified age, sex, and type of cancer as factors that predicted survival in patients with lung cancer.

Synchronous Carotid Body and Glomus Jugulare Tumors : A Case Report and Review of Literature

Md Atikur Rahman,Tejas Venkataram,Riad Habib,Nwoshin Jahan,Farid Raihan,Shamsul Alam,Ehsan Mahmood,Giuseppe E Umana,Bipin Chaurasia 대한신경외과학회 2024 Journal of Korean neurosurgical society Vol.67 No.1

Paragangliomas are rare neuroendocrine tumors that are usually benign in nature. They may be either familial or sporadic in their occurrence. Numerous neuroendocrine tumors are collectively included under the umbrella of paragangliomas. Among them, carotid body tumors and glomus jugulare tumors are extremely rare. Thus, we present a rare case of 29-year-old male who was admitted with hearing difficulties and tinnitus in the left ear, with swelling on the left side of the neck. Based on clinical and radiological findings, a diagnosis of left-sided glomus jugulare with carotid body tumor was made. The patient underwent a twostage surgery with an interval of approximately 2 months. Histopathology revealed a paraganglioma. Herein, we present the clinical features, imaging findings, management, and a brief review of literature on the classification, evaluation, and management of carotid body and glomus jugulare tumors. Paraganglioma is a slow-growing tumor. The synchronous occurrence of carotid body and glomus jugulare tumors is infrequent. Microsurgical resection remains the primary treatment modality. Therefore, our patient underwent two-stage surgery. The rarity of occurrence and the proximity and adherence to vital neurovascular structures have resulted in the treatment of paragangliomas remaining a challenge.