M. B. Ahmad

Modification of sago starch by graft copolymerization. Effect of reaction conditions on grafting parameters

Graft copolymerization of acrylonitrile onto sago starch was carried out by a free radical initiating process in which the ceric ion (Ce 4+ ) was used as an initiator. The reaction conditions significantly influence the graft copolymerization. The percentage of grafting, grafting efficiency and rate of grafting were all dependent on the concentration of ceric ammonium nitrate (CAN), acrylonitrile (AN), sago starch (AGU, anhydro glucose unit), mineral acid (H 2 SO 4 ) and the reaction temperature and period. The optimum yield was obtained when the concentrations of CAN, AN, AGU and H 2 SO 4 were used at 9.61×10 −3 , 0.653, 0.152 and 0.187 mol L −1 , respectively. The optimum temperature and reaction period were 50°C and 90 min, respectively. The rate of graft copolymerization was examined using the experimental results and the reaction mechanism. The polya1crylonitrile grafted sago starch was characterized by using FT-IR spectroscopy, DSC and SEM analysis.

Metal ions binding by chelating ligands from new polymer bearing amidoxime functional groups

A new polymer bearing amidoxime chelating resin was prepared from polyacrylonitrile (PAN) grafted sago starch and the significant binding capacity of metal ions by the resin was observed with a rapid sorption rate.

New polymer bearing hydroxamic acid chelating resin for binding of heavy metal ions

A new polymer containing the hydroxamic acid functional group was prepared from poly(methyl acrylate) grafted sago starch and the binding capacities of copper, iron, chromium, nickel, dysprosium, gadolinium and uranium were found excellent; other metal ions have significant sorption capacities.

Preparation and Characterization of Natural Rubber/Layered Double Hydroxide Nanocomposites

Nanocomposites of organo Zn‐Al layered double hydroxide (LDH) with natural rubber (SMR CV60) were successfully synthesized and characterized. To prepare the nanocomposites, a hydrophilic Zn‐Al layer double hydroxide (ZnAl LDH ‐NO3−) was first converted into the organophilic form by using dodecylsulphate ion (DS) as a guest in Zn‐Al layer double hydroxide (ZnAl LDH‐DS). Intercalation of dodecylsulphate anion into the interlayer of LDH increased the surface area and the porosity of LDH. Nanocomposites of NR / ZnAl LDH‐DS was then prepared by melt intercalation method using Haake internal mixer. The resulting compounds were then vulcanizated using the conventional method. X‐Ray diffractogram the organophilic ZnAl‐DS LDH shows the basal spacing of the ZnAl‐LDH expands from 0.89 nm with nitrate as the intergallery anions to 2.53 nm due to the accommodation of DS surfactant anions. After the compounding with the natural rubber, the basal spacing of ZnAl LDH‐DS in the composites is increased to 3.90 and 3.66 nm ...

Clinical Outcomes for Radial Artery Versus Saphenous Vein in Coronary Artery Bypass Graft Surgery

Aims : The aim this study was to see the clinical outcome of coronary artery bypass grafting (CABG) in patients of coronary artery disease and to compare the patients revascularisedwith left internal mammary artery (LIMA) and radial artery (RA) group with LIMA and reverse saphenous venous group(RSVG) group. Methods :Between March 2011 and November 2015, 200 patients underwent isolated CABG and were randomized in 1:1 fashion to receive either LIMA and RA grafts or LIMA and SVGs.All patients were operated in department of cardiac surgery, National Institute of Cardiovascular Disease (NICVD) and Hospital, Dhaka, Bangladesh and Al Helal Specialized Hospital, Mirpur- 10, Dhaka.Written consent was obtained from all patients prior to the procedure. Patients were followed for 4 years since index surgery for the composite of cardiovascular mortality, non-fatal myocardial infarction and need for repeat myocardial revascularization (either surgical or percutaneous). Data were collected either by phone or during visits. The data were entered into an electronic database (Access, Microsoft) and analyzed using the SPSS 16.0 software (SPSS Inc.). Results : This study reports on our series of 200 patients undergoing isolated, primary CABG using LIMA grafting and the SVG in one group, and RA grafting as the second conduit in the second group. Our data indicate that there is no difference in the long-term clinical outcome between the patients in whom RA or SVG is used as a second conduit, beside LIMA. Conclusion : In this small randomized study our data indicate that there is no difference in the 4 year clinical outcomes in relatively young patients between those having a RA or a saphenous vein graft used as a second conduit, beside LIMA, for surgical myocardial revascularization. University Heart Journal Vol. 13, No. 1, January 2017; 21-25

Early Evaluation of Renal Function in High-Risk Patients after Off-Pump Coronary Artery Bypass Grafting

Background: Cardiopulmonary bypass (CPB) is an unphysiological state and widely regarded as an important contributor to renal failure. Despite improvement in cardiopulmonary bypass technique, anesthesia and intensive care, perioperative renal dysfunction still represents a significant and potentially lethal complication after coronary artery bypass graft surgery (CABG). Renal dysfunction is a serious complication of coronary revascularization with CPB and results in increased morbidity, mortality and prolonged hospital stay. We compared the incidence of perioperative renal dysfunction in patients who underwent CABG, on-pump and off-pump (OPCAB) Methods: A total of 60 high -risk patients with ischaemic heart diseases were included in the study who underwent CABG. Out of the total 60 patients, 30 were in the Off-pump group (Group A) and the rest 30 were in the On-pump group (Group B). They were diagnosed as high-risk patients considering serum creatinine level>1.7mg/dl with age ≥60 years, ejection fraction 30-40%. Renal function was evaluated in both groups preoperatively and postoperatively (on 1st, 2nd and 7th postoperative day) and compared between two groups. Results: One patient in the On-pump group died on 6th postoperative day. Preoperative renal parameters were also similar and showed no statistically significant difference. So both groups were comparable. Comparison of renal parameter in OPCAB and on-pump CABG between preoperative and 7 th day postoperatively found in this study were blood urea 50.33±6.29, 39.87±4.8 vs 52.67±9.05 , 66.21±6.91 ; S. Creatinine (mg/dl) 1.94±0.19 , 1.28±0.19 vs 2.07±0.31 , 2.82±0.47; Creatinine Clearance Rate(ml/min) 46.61±4.1, 71.51±12.3 vs 46.53±4.6, 34.02±4.49 ; Urine output (ml/24 hrs)1692.7±71.53, 1755.7±82.91 vs 1591.2±78.76, 1492.1±196.29 all are statistically significant(p 0.05). Statistically significant difference of renal parameters in different postoperative days showed evidence of well preservation of renal function in OPCAB. Conclusion: Adaptation of OPCAB offers better preservation of renal function as well as better early postoperative outcome specially in high-risk CABG patients. Cardiovasc. j. 2016; 9(1): 23-30