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Pengoksidaan elektrokimia C. I. reactive orange 4 menggunakan elektrod komposit dwilogam

Norazzizi Nordin, Mohamed Rozali Othman

Sains Malaysiana, 2014;43:1761-1768.

Elektrod komposit dwilogam yang disediakan hasil campuran serbuk argentums (Ag) dan 'carbon (C) (dinamakan AgC-Pvc) memberikan hasil elektrolisis larutan pewarna C. I. Reactive Orange 4 (R04) yang tidak berwarna dan tanpa penghasilan enapan lumpur berbanding elektrod komposit dwilogam lain. Perbezaan nisbah komposisi serbuk Ag:C (30:70, 50:50 and 70:30) dalam penyediaan elektrod seterusnya diuji untuk melihat kesan perbezaan komposisi ini terhadap penyahwarnaan R04. Melalui persamaan Tafel yang diperoleh, elektrod Ag285C 665-PVC 5 yang menggunakan komposisi 30% Ag dan 70% C memberikan nilai perubahan ketumpatan arus, io yang lebih tinggi iaitu 3.555 mAl cm2 berbanding elektrod lain. Elektrod ini mempunyai aktiviti pemangkinan elektrokimia yang lebih baik berbanding elektrod lain. Hasil proses elektrolisis elektrod Ag285C66.5-PVC 5 terhadap larutan RO4 telah dianalisis menggunakan spektrofotometer uv-Nampak dan didapati proses degredasi kumpulan azo dalam pewarna tersebut telah berlaku selepas proses elektrolisis yang menghasilkan larutan tidak berwarna.

Matched MeSH terms: Cyclic N-Oxides
Surface modification of cellulose nanomaterial for urea biosensor application

Wan Elina Faradilla Wan Khalid, Lee YH, Mohamad Nasir Mat Arip

Sains Malaysiana, 2018;47:941-949.

Cellulose nanomaterial with rod-like structure and highly crystalline order, usually formed by elimination of the amorphous region from cellulose during acid hydrolysis. Cellulose nanomaterial with the property of biocompatibility and nontoxicity can be used for enzyme immobilization. In this work, urease enzyme was used as a model enzyme to study the surface modification of cellulose nanomaterial and its potential for biosensor application. The cellulose nanocrystal (CNC) surface was modified using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation to introduce the carboxyl group at C6 primary alcohol. The success of enzyme immobilization and surface modification was confirmed using chemical tests and measured using UV-Visible spectrophotometer. The immobilization strategy was then applied for biosensor application for urea detection. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used for electroanalytical characterization of the urea biosensor.

Matched MeSH terms: Cyclic N-Oxides
TEMPO-oxidized nanocellulose films derived from coconut residues: Physicochemical, mechanical and electrical properties

Hassan SH, Velayutham TS, Chen YW, Lee HV

Int J Biol Macromol, 2021 Jun 01;180:392-402.
PMID: 33737185 DOI: 10.1016/j.ijbiomac.2021.03.066

The present work focuses on the development of cellulose nanofibrils (CNF) film that derived from sustainable biomass resources, which potentially to work as bio-based conductive membranes that assembled into supercapacitors. The chemically purified cellulose was isolated from different parts of coconut (coconut shell and its husk) and further subjected to 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation for CNF preparation. Physicochemical properties of prepared CNFs were studied in terms of chemical characteristics & crystallinity, surface functionalities, surface morphology, and thermal properties. Both coconut shell-derived CNF and coconut husk-derived CNF fulfilled with nanocellulose's characteristics with fibres width ranged of 70-120 nm and 150-330 nm, respectively. CNF films were further prepared by solvent casting method to measure the modulus elasticity, piezoelectric and dielectric properties of the films. Mechanical study indicated that coconut shell-derived CNF film showed a higher value of elastic modulus than the coconut husk-derived CNF film, which was 8.39 GPa and 5.36 GPa, respectively. The effectiveness of electrical aspects for CNF films are well correlated with the crystallinity and thermal properties, associated with it's composition of different coconut's part.

Matched MeSH terms: Cyclic N-Oxides
Sono-assisted TEMPO oxidation of oil palm lignocellulosic biomass for isolation of nanocrystalline cellulose

Rohaizu R, Wanrosli WD

Ultrason Sonochem, 2017 01;34:631-639.
PMID: 27773290 DOI: 10.1016/j.ultsonch.2016.06.040

Highly stable and dispersible nanocrystalline cellulose (NCC) was successfully isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC), with yields of 93% via a sono-assisted TEMPO-oxidation and a subsequent sonication process. The sono-assisted treatment has a remarkable effect, resulting in an increase of more than 100% in the carboxylate content and a significant increase of approximately 39% in yield compared with the non-assisted process. TEM images reveal the OPEFB-NCC to have rod-like crystalline morphology with an average length and width of 122 and 6nm, respectively. FTIR and solid-state 13C-NMR analyses suggest that oxidation of cellulose chain hydroxyl groups occurs at C6. XRD analysis shows that OPEFB-NCC consists primarily of a crystalline cellulose I structure. Both XRD and 13C-NMR indicate that the OPEFB-NCC has a lower crystallinity than the OPEFB-MCC starting material. Thermogravimetric analysis illustrates that OPEFB-NCC is less thermally stable than OPEFB-MCC but has a char content of 46% compared with 7% for the latter, which signifies that the carboxylate functionality acts as a flame retardant.

Matched MeSH terms: Cyclic N-Oxides/chemistry*
Silylation of TEMPO oxidized nanocellulose from oil palm empty fruit bunch by 3-aminopropyltriethoxysilane

Indarti E, Marwan, Rohaizu R, Wanrosli WD

Int J Biol Macromol, 2019 Aug 15;135:106-112.
PMID: 31128174 DOI: 10.1016/j.ijbiomac.2019.05.161

Silylated cellulose has been successfully synthesized using TEMPO-oxidized nanocellulose (TEMPO-NC) from oil palm empty fruit bunch and 3-aminopropyltriethoxysilane (APS) in an ethanol/water medium at a low curing temperature of 40 °C as compared to those reported in the literature of above 100 °C. Confirmation of the grafting process can be seen from the new FTIR peaks at 810 cm-1 and 749 cm-1 which are attributed to the SiC stretching and SiC, and new 13C NMR signals at 10.3, 21.7 and 42.7 ppm which are assigned to C7, C8, and C9 of the silylated TEMPO-NC. The decrease in the intensities of the cellulose peaks of C2, C3, C6 and C6' in the 13C NMR indicates that silylation not only occurs on the hydroxyls, but more importantly on the TEMPO-NC carboxylic moiety of C6', which is postulated as being the primary factor for this successful modification. This is further corroborated by the emergence of three signals at 43, 61, and 69 ppm in the 29Si NMR spectrum which corresponds to Si(OSi)(OR)2R', Si(OSi)2(OR)R', and Si(OSi)3R' units respectively. Additional evidence is provided by the EDX which shows an increase in Si weight percent of 1.94 after reaction. This silylated cellulose from OPEFB has the potentials to be used as bionanocomposite reinforcing elements.

Matched MeSH terms: Cyclic N-Oxides/chemistry*
Cost-Effectiveness of Clinical Pharmacy Education on Infection Management among Patients with Chronic Kidney Disease in an Indonesian Hospital

Nasution A, Syed Sulaiman SA, Shafie AA

Value Health Reg Issues, 2013 May;2(1):43-47.
PMID: 29702851 DOI: 10.1016/j.vhri.2013.02.009

OBJECTIVES: This study evaluated the clinical and economic impacts of clinical pharmacy education (CPE) on infection management among patients with chronic kidney disease (CKD) stages 4 and 5 in Haji Adam Malik Hospital, Indonesia.
METHODS: A quasi-experimental economic evaluation comparing CPE impact on 6-month CKD mortality was conducted on the basis of payer perspective. The experimental group (n = 63) received care by health care providers who were given CPE on drug-related problems and dose adjustment. The control group (n = 80) was based on the historical cohort of patients who received care before the CPE. Measure of clinical outcome applied in this study was number of lives saved/100 patients treated. Cost-effectiveness ratios for CKD stages 4 and 5 patients without CPE and with CPE and incremental cost-effectiveness ratios (ICERs) for CKD stages 4 and 5 patients were analyzed.
RESULTS: Lives saved (%) in the treatment of CKD without CPE: CKD stage 4, 78.57; CKD stage 5, 57.58. Lives saved (%) in the treatment of CKD with CPE: CKD stage 4, 88.89; CKD stage 5, 65.45. Cost-effectiveness ratios for stage 4 with and without CPEs were Rp3,348,733.27 and Rp3,519,931.009, respectively. Cost-effectiveness ratios for stage 5 with and without CPEs were Rp7,137,874.93 and Rp7,871,822.27, respectively. ICERs were Rp2,045,341.22 for CKD stage 4 and Rp1,767,585.60 for CKD stage 5.
CONCLUSIONS: Treatment of CKD stages 4 and 5 with CPE was more effective and cost-effective compared with treatment of CKD stages 4 and 5 without CPE. The ICERs indicated that extra costs were required to increase life saved in both stages.

Matched MeSH terms: Cyclic N-Oxides
The superoxide dismutase mimetic tempol blunts diabetes-induced upregulation of NADPH oxidase and endoplasmic reticulum stress in a rat model of diabetic nephropathy

De Blasio MJ, Ramalingam A, Cao AH, Prakoso D, Ye JM, Pickering R, et al.

Eur J Pharmacol, 2017 Jul 15;807:12-20.
PMID: 28438648 DOI: 10.1016/j.ejphar.2017.04.026

Endoplasmic reticulum (ER) stress contributes to progression of diabetic nephropathy, which promotes end-stage renal failure in diabetic patients. This study was undertaken to investigate the actions of tempol and ramipril, pharmacological agents that target the consequences of NADPH oxidase, on diabetic nephropathy in a rat model of type 1 diabetes, with an emphasis on markers of ER stress. Male Sprague-Dawley rats were injected intravenously with a single bolus of streptozotocin (55mg/kg) to induce type 1 diabetes. An additional age-matched group of rats was administered with citrate vehicle as controls. After 4 weeks of untreated diabetes, rats received tempol (1.5mM/kg/day subcutaneously, n=8), ramipril (1mg/kg/day in drinking water, n=8) or remained untreated for an additional 4 weeks (n=7). After 8 weeks of diabetes in total, kidneys were collected for histological analysis, gene expression and protein abundance. Tempol and ramipril blunted diabetes-induced upregulation of NADPH oxidase isoforms (Nox4, Nox2, p47phox), accompanied by an amelioration of diabetes-induced glomerular injury (podocin, nephrin, Kim-1), tubulo-interstitial fibrosis (TGFβ1, TGFβ-R2, pSMAD3, α-SMA) and pro-inflammatory cytokines (TNFα, MCP-1, ANX-A1, FPR2) expression. In addition, the diabetes-induced renal ER stress, evidenced by increased expression of GRP-78 chaperone and stress-associated markers ATF4, TRB3, as well as XBP1s, phospho-p38 mitogen-activated protein kinase (MAPK) and 3-nitrotyrosination, were all attenuated by tempol and ramipril. These observations suggest that antioxidant approaches that blunt NADPH upregulation may attenuate diabetic nephropathy, at least in part by negatively regulating ER stress and inflammation, and hence ameliorating kidney damage.

Matched MeSH terms: Cyclic N-Oxides/pharmacology*; Cyclic N-Oxides/therapeutic use
Hydrogen sulphide and tempol treatments improve the blood pressure and renal excretory responses in spontaneously hypertensive rats

Ahmad FU, Sattar MA, Rathore HA, Tan YC, Akhtar S, Jin OH, et al.

Ren Fail, 2014 May;36(4):598-605.
PMID: 24502512 DOI: 10.3109/0886022X.2014.882218

Oxidative stress and suppressed H2S production lead to increased renal vascular resistance, disturbed glomerular hemodynamics, and abnormal renal sodium and water handling, contribute to the pathogenesis and maintenance of essential hypertension in man and the spontaneously hypertensive rat. This study investigated the impact of H2S and tempol alone and in combination on blood pressure and renal hemodynamics and excretory functions in the SHR. Groups of WKY rats or SHR (n=6) were treated for 4 weeks either as controls or received NaHS (SHR+NaHS), tempol (SHR+Tempol), or NaHS plus tempol (SHR+NaHS +Tempol). Metabolic studies were performed on days 0, 14, and 28, thereafter animals were anaesthetized to measure renal hemodynamics and plasma oxidative and antioxidant markers. SHR control rats had higher mean arterial blood pressure (140.0 ± 2 vs. 100.0 ± 3 mmHg), lower plasma and urinary H2S, creatinine clearance, urine flow rate and urinary sodium excretion, and oxidative stress compared to WKY (all p<0.05). Treatment either with NaHS or with tempol alone decreased blood pressure and oxidative stress and improved renal hemodynamic and excretory function compared to untreated SHR. Combined NaHS and tempol therapy in SHRs caused larger decreases in blood pressure (∼20-22% vs. ∼11-15% and ∼10-14%), increases in creatinine clearance, urinary sodium excretion and fractional sodium excretion and up-regulated the antioxidant status compared to each agent alone (all p<0.05). These findings demonstrated that H2S and tempol together resulted in greater reductions in blood pressure and normalization of kidney function compared with either compound alone.

Matched MeSH terms: Cyclic N-Oxides/pharmacology*
The effects of tempol on renal function and hemodynamics in cyclosporine-induced renal insufficiency rats

Chia TY, Sattar MA, Abdulla MH, Rathore HA, Ahmad Fu, Kaur G, et al.

Ren Fail, 2013 Aug;35(7):978-88.
PMID: 23822648 DOI: 10.3109/0886022X.2013.809563

This study investigated the effects of tempol, a superoxide dismutase (SOD) mimetic and L-NAME, a nitric oxide (NO) synthase inhibitor on the renal function and hemodynamics in cyclosporine A (CsA) induced renal insufficiency rats. Male Sprague-Dawley rats were treated with either vehicle (C), tempol (T, 1 mmol/L in drinking fluid), L-NAME (L, 1 mmol/L in drinking fluid), CsA (Cs, 25 mg/kg/day via gavage), CsA plus tempol (TCs), CsA plus L-NAME (LCs) or CsA plus a combination of tempol and L-NAME (TLCs) for 21 consecutive days. At the end of treatment regimen, the renal responses to noradrenaline (NA), phenylephrine (PE), methoxamine and angiotensin II (Ang II) were determined. Cs and LCs rats had lower creatinine clearance (0.7 ± 0.1 and 0.6 ± 0.5 vs. 1.3 ± 0.2 mL/min/kg) and fractional excretion of sodium (0.12 ± 0.02 and 0.17 ± 0.01 vs. 0.67 ± 0.04%) but higher systolic blood pressure (145 ± 2 and 178 ± 4 vs. 116 ± 2) compared to the control (all p

Matched MeSH terms: Cyclic N-Oxides/pharmacology*
The effect of nitric oxide on the production of cyclic AMP by a human osteoblast (HOS) cell line stimulated with hydroxyapatite

Sosroseno W, Sugiatno E, Samsudin AR, Ibrahim MF

Biomed Pharmacother, 2008 Jun;62(5):328-32.
PMID: 17988826

The aim of the present study was to determine the effect of nitric oxide (NO) on the production of cyclic AMP (cAMP) by a human osteoblast cell line (HOS cells) stimulated with hydroxyapatite. Cells were cultured on the HA surfaces with or without the presence of NO donors (SNAP and NAP) for 3 days. The effect of adenylyl cyclase inhibitor (SQ22536), NO scavenger (carboxy PTIO) or endothelial nitric oxide synthase (eNOS) inhibitor (L-NIO), was assessed by adding these to the cultures of HA-stimulated HOS cells with or without the presence of SNAP. Furthermore, HOS cells were pre-treated with anti-human integrin alphaV antibody prior to culturing on HA surfaces with or without the presence of SNAP. The levels of cAMP and cGMP were determined from the 3-day culture supernatants. The results showed that the production of cAMP but not cGMP by HA-stimulated HOS cells was augmented by SNAP. SQ22536 and carboxy PTIO suppressed but L-NIO only partially inhibited the production of cAMP by HA-stimulated HOS cells with or without the presence of exogenous NO. Pre-treatment of the cells with anti-human integrin alphaV antibody suppressed the production of cAMP by HA-stimulated HOS cells with or without the presence of NO. Therefore, the results of the present study suggest that NO may up-regulate the production of cAMP, perhaps, by augmenting adenylyl cyclase activity initiated by the binding between HOS cell-derived integrin alphaV and HA surface.

Matched MeSH terms: Cyclic N-Oxides/pharmacology