Preparation of γ-alumina/silica core–shell abrasives and their chemical mechanical polishing performances on sapphire substrates

Micro & nano letters

article

Xin Wang¹  Hong Lei¹ 

[1] Research Center of Nano-science and Nano-technology, Shanghai University

关键词: scanning electron microscopy;    abrasives;    surface roughness;    friction;    X-ray photoelectron spectra;    abrasion;    secondary ion mass spectra;    silicon compounds;    alumina;    transmission electron microscopy;    chemical mechanical polishing;    composite materials;    materials preparation;    time of flight mass spectra;    surface morphology;    sapphire;    core–shell structure;    time-of-flight secondary ion mass spectroscopy;    scanning electron microscopy;    transmission electron microscopy;    sapphire substrates;    chemical effect;    mechanical friction;    chemical mechanical polishing;    global planarisation technology;    γ-alumina-silica core-shell abrasives;    morphological properties;    surface roughness;    X-ray photoelectron spectroscopy;    solid-state chemical reactions;    wear model;    Al2O3;    Al2O3-SiO2;   

DOI  :  10.1049/mnl.2018.0166

学科分类：计算机科学（综合）

来源: Wiley

【 摘 要 】

Diabetic Nephropathy(DN) is a complex disease manifested by persistence microalbuminuria   occurring due to the interaction between hemodynamic and metabolic pathway that activates the local renin-angiotensin-aldosterone system resulting in a decline in renal functions. This study aimed to quantify the associations between serum aldosterone concentration and fetuin- A as a marker of calcification in type 2 diabetic patients with and without microalbuminuria from one side, and study the possible relationship between aldosterone and fetuin-A with glycemic indices, serum electrolyte, renal function and microalbuminuria and body mass index from the other side. A case-control study involved eighty-six adult subjects classified into three groups after testing urine microalbumin including thirty-two diabetics type 2 patients with positive microalbuminuria and twenty-eight diabetics type 2 patients with negative microalbuminuria and 26 healthy subjects during their visit to AL kindy specialized Center for Endocrinology and Diabetes / Baghdad. Those patients were compared to control group of 26 apparently healthy subjects, fasting blood samples was obtained from each of them in one occasion only to measure: fasting serum glucose, electrolyte, aldosterone,  fetuin-A, urea, and creatinine. In addition to glycoheamoglobin, glomerular filtration rate and body mass index. Despite the presence of microalbuminuria in  thirty-two of the studied diabetics, there was no positive correlation between aldosterone and fetuin- A, besides that no significant variations in serum aldosterone ,glomerular filtration rate(GFR) values, while both groups showed a significant increase in fasting serum glucose and glycaoheamoglobin ,significant decrease in serum sodium and chloride in comparison with the control group , significant increase was detected  in serum fetuin-A mean  values in microalbuminuric diabetics. Whereas, negative microalbuminuric diabetics measures expressed a positive correlation between both serum sodium and chloride levels and fetuin -A. The conclusion of this study diabetic patient are prone to vascular calcification (VC)  might be due to increase in aldosterone level or due to diabetic itself  from this study we can conclude microalbuminuria can occur without a decline in renal function or a change in estimated GFR ,no definite correlation occur between aldosterone and fetuin- A, fetuin- A mean values are higher in diabetic patient with microalbuminuria compared to diabetic patients without microalbuminuria and control group and this referred to uncontrolled diabetes ,aldosterone show a correlation with  weight and body mass index while fetuin- A does not show  such correlation. In general, electrolyte disturbances (hypernatremia) is more obvious in this study  , and its occurrence is due to diabetic (osmotic diuresis) or drugs, while sodium retention which is a sign of aldosterone increment does not occur.  Hypochloremia that occur in this study is due to chloride and it is in parallel with sodium level.

【 授权许可】

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