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Fulltext Evaluation of Adsorptive Characteristics of Cow Dung and Rice Husk Ash for Removal of Aqueous Glyphosate and Aminomethylphoshonic Acid

Garba J, Samsuri WA, Othman R, Hamdani MSA

Sci Rep, 2019 11 27;9(1):17689.
PMID: 31776374 DOI: 10.1038/s41598-019-54079-0

Glyphosate (GLY) is a major herbicide used throughout the world, and its continuous application has become an environmental issue. Adsorption is an important mechanism for removing organic contaminant in water. The present study characterized cow dung (CD) and rice husk ash (RHA), and determined the adsorption-desorption of GLY and its metabolite, aminomethylphoshonic acid (AMPA), on to them. The results revealed that both CD and RHA were alkaline and had no or low content of arsenic, cadmium, chromium and lead. The CD had lower surface area (13.104 mg2g-1) than RHA (21.500 m2g-1). The CD contained amines, phenol, ethers and carboxylic functional groups, while in addition to carboxylic and ether, RHA contains siloxane. Both CD and RHA had high affinities for GLY and AMPA. The Freundlich sorption coefficient (Kf) on AMPA were 2.915 and 2.660 for CD and RHA, respectively, while the values on GLY were 1.168 and 1.166 (mg g-1) for CD and RHA, respectively. Desorption of GLY only occurred at lower concentrations, while no desorption of AMPA was recorded, indicating their strong adsorption on CD and RHA. Considering their availabilities and affordable prices, both CD and RHA can be recommended as economical adsorbent for the removal of GLY and AMPA.

Matched MeSH terms: Ethers
Interactions of Flavone and Steroid from A. subintegra as Potential Inhibitors for Porcine Pancreatic Lipase

Ibrahim M, Abdul Azziz SSS, Wong CF, Bakri YM, Abdullah F

Curr Comput Aided Drug Des, 2020;16(6):698-706.
PMID: 31648647 DOI: 10.2174/1573409915666191015112320

BACKGROUND: Obesity is one serious health condition that contributes to various chronic diseases. The inhibition of pancreatic lipase is a promising treatment for obesity.
OBJECTIVE: The present study was designed to investigate anti-porcine pancreatic lipase effect of isolated compounds from Aquilaria subintegra and its mechanism.
METHODS: Compounds were isolated with serial column chromatography and their structure were identified using spectroscopic methods. Isolated compounds were tested for anti-lipase potential activity using colorimetric assay. The prediction of energy binding between isolated compounds and enzyme was described using YASARA software.
RESULTS: Four compounds were successfully isolated from the bark of A. subintegra, namely, 5- hydroxy-7,4'-dimethoxyflavone, luteolin-7,3',4'-trimethyl ether, 5,3'-dihydroxy-7,4'-dimethoxyflavone and β-sitosterol. The results indicated that all compounds displayed promising pancreatic lipase inhibitory activity ranging between of 6% to 53% inhibition. Compound 5-hydroxy-7,4'- dimethoxyflavone was a competitive inhibitor and decreases the enzyme catalysis. Meanwhile, β- sitosterol was a non- competitive inhibitor since the latter was bind allosterically toward enzyme.
CONCLUSION: This finding is significant for further investigation of bioactive compounds from A. subintegra on animal study.

Matched MeSH terms: Ethers
Fulltext Comparison of cardiovascular responses between remifentanil and fentanyl on laryngoscopy and tracheal intubation in patients undergoing elective surgery

Lai, S.C., Choy, Y.C.

Journal of Surgical Academia, 2014;4(1):20-25.
MyJurnal

This was a prospective, randomized, double-blind study comparing the effect of remifentanil and fentanyl on cardiovascular responses from laryngoscopy and tracheal intubation. Forty-four ASA I or II patients aged between 18-65 yrs scheduled for elective surgery under general anaesthesia, were recruited and randomized into two groups. Each patient in Group R received remifentanil of 0.5 mcg/kg bolus over 30 seconds followed by an infusion of 0.25 mcg/kg/min and each patient in Group F received fentanyl of 2 mcg/kg bolus over 30 seconds followed by an infusion of normal saline. Anaesthesia was then induced with propofol, rocuronium and 2% sevoflurane with 100% oxygen. Cardiovascular changes were recorded every minute for 3 minutes after induction and 5 minutes after tracheal intubation. The heart rate remained stable throughout the induction and intubation period in both groups. None of the patients in the remifentanil group develop bradycardia. Systolic blood pressure (SBP) and mean arterial pressure (MAP) were significantly lower in the fentanyl group at the 3rd minute post-induction and 5th minute post- intubation (p < 0.05). Diastolic blood pressure (DBP) in the fentanyl group was significantly lower at the 2nd and 3rd minute post-induction and 4th and 5th minute post-intubation (p < 0.05). The blood pressure remained stable for the remifentanil group throughout the induction and intubation period. Six patients (27.2%) in the fentanyl group and one patient (4.5%) in the remifentanil group experienced hypertension. Three patients (13.7%) from each group experienced hypotensive episodes. In conclusion, remifentanil 0.5 mcg/kg bolus followed by 0.25 mcg/kg/min infusion resulted in SBP, MAP and DBP remained slightly lower than baseline throughout the whole period but still consider stable, as these changes were not statistically significant.

Matched MeSH terms: Methyl Ethers
Fulltext Ascariasis among orang asli children at pos lenjang, Pahang, malaysia

Hartini, Y., Mohamed Kamel, A.G.

Medicine & Health, 2010;5(2):60-65.
MyJurnal

A cross-sectional study was carried out in 2006 to determine the prevalence of Ascaris lumbricoides infection among Orang Asli (aborigines) children in Pos Lenjang, Pahang. A total of 71 faecal samples were collected from the children (40 girls and 31 boys) aged between 1-12 years. The samples were examined for the presence of the ova of A. lumbricoides using direct faecal smear and formalin-ether concentration techniques. 42.3%. The prevalence of A. lumbricoides infection was found to be slightly higher in males (45.2%) compared to females (40%) (p>0.05). The school-aged children showed higher prevalence of infection (48.6%) as compared to the preschool children (35.3%) (p

Matched MeSH terms: Ethers
Comparison between the use of LMA™ and SLIPA™ in patients undergoing minor surgeries

Wan Rahiza, W.M., Nurlia, Y., Abd Rahman, I., Esa, K., Nadia, M.N., Raha, A. R.

Journal of Surgical Academia, 2012;2(1):8-13.
MyJurnal

Supraglottic airway devices have been used as safe alternatives to endotracheal intubation in appropriate types of surgery. This was a prospective, randomised, single blind study comparing the use of LMA™ and SLIPA™ in terms of ease of insertion, haemodynamic changes and occurrence of adverse effects (e.g. blood stains on the device upon removal and sore throat). A total of 62 ASA I or II patients, aged between 18 to 70 years were recruited for this study. Patients were randomised into two groups; LMA™ and SLIPA™ group. Following induction of anaesthesia, an appropriate sized LMA™ or SLIPA™ was inserted after ensuring adequate depth of anaesthesia. Anaesthesia was maintained with oxygen, nitrous oxide and sevoflurane. The ease of insertion was graded and haemodynamic changes were recorded at 2 minute intervals up to 10 minutes after insertion of the airway devices. The presence of blood stains upon airway device removal at the end of surgery and incidence of sore throat was also recorded. No difficult insertion was experienced in either of these devices. Insertion was either easy [LMA™ 87.1% versus SLIPA™ 80.6% (p = 0.49)] or moderate [LMA™ 12.9% versus SLIPA™ 19.4% (p = 0.16)]. Throughout the study period, the haemodynamic changes that occurred in both groups were not statistically different. Traces of blood were noted on the surface of the device in 9.7% of patients in the SLIPA™ group versus 6.5% of patients in the LMA™ group. The incidence of sore throat was recorded in 12.9% versus 19.4% of patients in the SLIPA™ and the LMA™ groups respectively. These findings were not statistically significant. In conclusion, this study showed no significant differences between the use of LMA™ and SLIPA™ in terms of ease of insertion, haemodynamic changes and adverse effects in patients undergoing minor surgical procedures.

Matched MeSH terms: Methyl Ethers
Field-enhanced sample injection-micelle to solvent stacking in nonaqueous capillary electrophoresis

Thang LY, See HH, Quirino JP

Talanta, 2016 Dec 01;161:165-169.
PMID: 27769394 DOI: 10.1016/j.talanta.2016.08.054

The low conductivity of separation electrolytes employed in nonaqueous capillary electrophoresis (NACE) limits the use of on-line sample concentration or stacking by field enhancement. Herein, micelle-to-solvent stacking (MSS) was performed by the simple injection of a micellar solution plug prior to electrokinetic injection of sample prepared under field-enhanced stacking conditions (known as field-enhanced sample injection, FESI). The proposed approach allowed a 214-625-fold improvement in peak signals for targeted anticancer drugs (e.g., tamoxifen) and its major metabolites in NACE using 100% methanol-based separation electrolyte that comprised of 7.5mM deoxycholic acid sodium salt, 15mM acetic acid and 1mM 18-crown-6. These improvements yielded tamoxifen and its metabolites with 2-5 times better stacking efficiency as compared to those obtained without micellar solution injection or FESI only. This is comparable to the results typically achieved when FESI is combined with isotachophoresis (electrokinetic supercharging). The FESI-MSS-NACE was tested for the measuring levels of target drugs in plasma. The analytical figures of merit are also reported.

Matched MeSH terms: Crown Ethers
Design, synthesis, and evaluation of novel diphenyl ether derivatives against drug-susceptible and drug-resistant strains of Mycobacterium tuberculosis

Kar SS, Bhat VG, Shenoy VP, Bairy I, Shenoy GG

Chem Biol Drug Des, 2019 01;93(1):60-66.
PMID: 30118192 DOI: 10.1111/cbdd.13379

In our efforts to develop druggable diphenyl ethers as potential antitubercular agents, a series of novel diphenyl ether derivatives (5a-f, 6a-f) were designed and synthesized. The representative compounds showed promising in vitro activity against drug-susceptible, isoniazid-resistant, and multidrug-resistant strains of Mycobacterium tuberculosis with MIC values of 1.56 μg/ml (6b), 6.25 μg/ml (6a-d), and 3.125 μg/ml (6b-c), respectively. All the synthesized compounds exhibited satisfactory safety profile (CC50 > 300 μg/ml) against Vero and HepG2 cells. Reverse phase HPLC method was used to probe the physicochemical properties of the synthesized compounds. This series of compounds demonstrated comparatively low logP values. pKa values of representative compounds indicated that they were weak acids. Additionally, in vitro human liver microsomal stability assay confirmed that the synthesized compounds possessed acceptable stability under study conditions. The present study thus establishes compound 6b as the most promising antitubercular agent with acceptable drug-likeness.

Matched MeSH terms: Phenyl Ethers
Fulltext Conjugating uncoupler compounds with hydrophobic hydrocarbon chains to achieve adipose tissue selective drug accumulation

Ng MY, Song ZJ, Venkatesan G, Rodriguez-Cuenca S, West JA, Yang S, et al.

Sci Rep, 2024 Feb 28;14(1):4932.
PMID: 38418847 DOI: 10.1038/s41598-024-54466-2

One potential approach for treating obesity is to increase energy expenditure in brown and white adipose tissue. Here we aimed to achieve this outcome by targeting mitochondrial uncoupler compounds selectively to adipose tissue, thus avoiding side effects from uncoupling in other tissues. Selective drug accumulation in adipose tissue has been observed with many lipophilic compounds and dyes. Hence, we explored the feasibility of conjugating uncoupler compounds with a lipophilic C8-hydrocarbon chain via an ether bond. We found that substituting the trifluoromethoxy group in the uncoupler FCCP with a C8-hydrocarbon chain resulted in potent uncoupling activity. Nonetheless, the compound did not elicit therapeutic effects in mice, likely as a consequence of metabolic instability resulting from rapid ether bond cleavage. A lipophilic analog of the uncoupler compound 2,6-dinitrophenol, in which a C8-hydrocarbon chain was conjugated via an ether bond in the para-position (2,6-dinitro-4-(octyloxy)phenol), exhibited increased uncoupling activity compared to the parent compound. However, in vivo pharmacokinetics studies suggested that 2,6-dinitro-4-(octyloxy)phenol was also metabolically unstable. In conclusion, conjugation of a hydrophobic hydrocarbon chain to uncoupler compounds resulted in sustained or improved uncoupling activity. However, an ether bond linkage led to metabolic instability, indicating the need to conjugate lipophilic groups via other chemical bonds.

Matched MeSH terms: Ethers
Sedimentary PBDEs in urban areas of tropical Asian countries

Kwan CS, Takada H, Mizukawa K, Saha M, Rinawati, Santiago EC

Mar Pollut Bull, 2013 Nov 15;76(1-2):95-105.
PMID: 24120227 DOI: 10.1016/j.marpolbul.2013.09.023

Polybrominated diphenyl ethers (PBDEs) were measured in surface sediment samples collected from urban canals or rivers in Lao PDR, Cambodia, Vietnam, India, Indonesia, Thailand, the Philippines, Malaysia and Japan. The total PBDE concentrations in the sediments ranged from 0.83 to 3140 ng/g dry wt. BDE-209 was predominant, ranging from 43% to 97% of total PBDEs, followed by nona-BDEs and some detectable concentrations of BDEs 47, 49, 99, 100, 153, 154 and 183. Sedimentary PBDE levels in Malaysia, Cambodia, the Philippines and Thailand were generally higher than those reported for highly industrialized countries. Spatial distribution of PBDEs indicated that inland sources may impact coastal areas. The presence of BDE congeners which are not contained in technical mixtures and the higher proportions of nona-BDEs relative to BDE-209 in the sediments were identified as indicators of debromination. BDE-209 was possibly debrominated under anaerobic conditions in some of the sediment samples.

Matched MeSH terms: Halogenated Diphenyl Ethers/analysis*
Hollow fiber liquid-phase microextraction for the determination of trace amounts of rosiglitazone (anti-diabetic drug) in biological fluids using capillary electrophoresis and high performance liquid chromatographic methods

Al Azzam KM, Makahleah A, Saad B, Mansor SM

J Chromatogr A, 2010 Jun 4;1217(23):3654-9.
PMID: 20409552 DOI: 10.1016/j.chroma.2010.03.055

A three-phase hollow fiber liquid-phase microextraction (HF-LPME) coupled either with capillary electrophoresis (CE) or high performance liquid chromatography (HPLC) with UV detection methods was successfully developed for the determination of trace levels of the anti-diabetic drug, rosiglitazone (ROSI) in biological fluids. The analyte was extracted into dihexyl ether that was immobilized in the wall pores of a porous hollow fiber from 10 mL of aqueous sample, pH 9.5 (donor phase), and was back extracted into the acceptor phase that contained 0.1M HCl located in the lumen of the hollow fiber. Parameters affecting the extraction process such as type of extraction solvent, HCl concentration, donor phase pH, extraction time, stirring speed, and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; donor phase pH, 9.5; acceptor phase, 0.1M HCl; stirring speed, 600 rpm; extraction time, 30 min; without addition of salt), enrichment factor of 280 was obtained. Good linearity and correlation coefficients of the analyte was obtained over the concentration ranges of 1.0-500 and 5.0-500 ng mL(-1) for the HPLC (r(2)=0.9988) and CE (r(2)=0.9967) methods, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for the HPLC and CE methods were (0.18, 2.83) and (0.56, 5.00) ng mL(-1), respectively. The percent relative standard deviation (n=6) for the extraction and determination of three concentration levels (10, 250, 500 ng mL(-1)) of ROSI using the HPLC and CE methods were less than 10.9% and 13.2%, respectively. The developed methods are simple, rapid, sensitive and are suitable for the determination of trace amounts of ROSI in biological fluids.

Matched MeSH terms: Ethers/chemistry
Extraction of biogenic amines using sorbent materials containing immobilized crown ethers

Saaid M, Saad B, Rahman IA, Ali AS, Saleh MI

Talanta, 2010 Jan 15;80(3):1183-90.
PMID: 20006072 DOI: 10.1016/j.talanta.2009.09.006

Three sorbent materials (A18C6-MS, DA18C6-MS and AB18C6-MS) based on the crown ether ligands, 1-aza-18-crown-6, 1,4,10,13-tetraoxa-7,16-diazacyclo octadecane and 4'-aminobenzo-18-crown-6, respectively, were prepared by the chemical immobilization of the ligand onto mesoporous silica support. The sorbents were characterized by FT-IR, scanning electron microscopy-energy dispersive X-ray microanalysis, elemental analysis and nitrogen adsorption-desorption test. The applicability of the sorbents for the extraction of biogenic amines by the batch sorption method was extensively studied and evaluated as a function of pH, biogenic amines concentration, contact time and reusability. Under the optimized conditions, all the sorbents exhibited highest selectivity toward spermidine (SPD) compared to other biogenic amines (tryptamine, putrescine, histamine and tyramine). Among the sorbents, AB18C6-MS offer the highest capacity and best selectivity towards SPD in the presence of other biogenic amines. The AB18C6-MS sorbent can be repeatedly used three times as there was no significant degradation in the extraction of the biogenic amines (%E>85). The optimized procedure was successfully applied for the separation of SPD in food samples prior to the reversed-phase high performance liquid chromatography separation.

Matched MeSH terms: Crown Ethers/chemistry*
Determination of quinocide as impurity in primaquine tablets by capillary zone electrophoresis

Elbashir AA, Saad B, Ali AS, Saleh MI, Aboul-Enein HY

Biomed Chromatogr, 2009 May;23(5):464-71.
PMID: 19016231 DOI: 10.1002/bmc.1137

A capillary zone electrophoretic method has been developed and validated for the determination of the impurity quinocide (QC) in the antimalarial drug primaquine (PQ). Different buffer additives such as native cyclodextrins and crown ethers were evaluated. Promising results were obtained when either beta-cyclodextrin (beta-CD) or 18-crown-6 ether (18C6) were used. Their separation conditions such as type of buffer and its pH, buffer additive concentration, applied voltage capillary temperature and injection time were optimized. The use of 18C6 offers slight advantages over beta-CD such as faster elution times and improved resolution. Nevertheless, migration times of less than 5 min and resolution factors (R(s)) in the range of 2-4 were obtained when both additives were used. The method was validated with respect to selectivity, linearity, limits of detection and quantitation, analytical precision (intra- and inter-day variability) and repeatability. Concentrations of 2.12 and 2.71% (w/w) of QC were found in pharmaceutical preparations of PQ from two different manufacturers. A possible mechanism for the successful separation of the isomers is also discussed.

Matched MeSH terms: Crown Ethers/chemistry
Soil contamination by brominated flame retardants in open waste dumping sites in Asian developing countries

Eguchi A, Isobe T, Ramu K, Tue NM, Sudaryanto A, Devanathan G, et al.

Chemosphere, 2013 Mar;90(9):2365-71.
PMID: 23149186 DOI: 10.1016/j.chemosphere.2012.10.027

In Asian developing countries, large amounts of municipal wastes are dumped into open dumping sites each day without adequate management. This practice may cause several adverse environmental consequences and increase health risks to local communities. These dumping sites are contaminated with many chemicals including brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). BFRs may be released into the environment through production processes and through the disposal of plastics and electronic wastes that contain them. The purpose of this study was to elucidate the status of BFR pollution in municipal waste dumping sites in Asian developing countries. Soil samples were collected from six open waste dumping sites and five reference sites in Cambodia, India, Indonesia, Malaysia, and Vietnam from 1999 to 2007. The results suggest that PBDEs are the dominant contaminants in the dumping sites in Asian developing countries, whereas HBCD contamination remains low. Concentrations of PBDEs and HBCDs ranged from ND to 180 μg/kg dry wt and ND to 1.4 μg/kg dry wt, respectively, in the reference sites and from 0.20 to 430 μg/kg dry wt and ND to 2.5 μg/kg dry wt, respectively, in the dumping sites. Contamination levels of PBDEs in Asian municipal dumping sites were comparable with those reported from electronic waste dismantling areas in Pearl River delta, China.

Matched MeSH terms: Halogenated Diphenyl Ethers/analysis
Sevoflurane for dental extraction in children with Tetralogy of Fallot

Chiu CL, Wang CY

Paediatr Anaesth, 1999;9(3):268-70.
PMID: 10320610

Two children with Tetralogy of Fallot presented for dental extraction. Anaesthesia was induced rapidly and smoothly by inhalation of sevoflurane. We discussed the advantages of sevoflurane as an induction agent as compared to halothane in these children.

Matched MeSH terms: Methyl Ethers/administration & dosage*
Proline-Modified UIO-66 as Nanocarriers to Enhance Candida rugosa Lipase Catalytic Activity and Stability for Electrochemical Detection of Nitrofen

Cheng Y, Lai OM, Tan CP, Panpipat W, Cheong LZ, Shen C

ACS Appl Mater Interfaces, 2021 Jan 27;13(3):4146-4155.
PMID: 33440928 DOI: 10.1021/acsami.0c17134

Immobilization can be used to improve the stability of lipases and enhances lipase recovery and reusability, which increases its commercial value and industrial applications. Nevertheless, immobilization frequently causes conformational changes of the lipases, which decrease lipase catalytic activity. in the present work, we synthesized UIO-66 and grafted UIO-66 crystals with proline for immobilization of Candida rugosa lipase (CRL). As indicated by steady-state fluorescence microscopy, grafting of proline onto UIO-66 crystals induced beneficial conformational change in CRL. CRL immobilized on UIO-66/Pro (CRL@UIO-66/Pro) demonstrated higher enzyme activity and better recyclability than that immobilized on UIO-66 (CRL@UIO-66) in both hydrolysis (CRL@UIO-66/Pro: 0.34 U; CRL@UIO-66: 0.15 U) and transesterification (CRL@UIO-66/Pro: 0.93 U; CRL@UIO-66: 0.25 U) reactions. The higher values of kcat and kcat/Km of CRL@UIO-66/Pro also showed that it had better catalytic efficiency as compared to CRL@UIO-66. It is also worth noting that CRL@UIO-66/Pro (0.93 U) demonstrated a much higher transesterification activity as compared to free CRL (0.11 U), indicating that UIO-66/Pro has increased the solvent stability of CRL. Both CRL@UIO-66 and CRL@UIO-66/Pro were also used for the fabrication of biosensors for nitrofen with a wide linear range (0-100 μM), lower limit of detection, and good recovery rate.

Matched MeSH terms: Phenyl Ethers/analysis*
Levels of trace elements, methylmercury and polybrominated diphenyl ethers in foraging green turtles in the South China region and their conservation implications

Ng CKY, Lam JCW, Zhang XH, Gu HX, Li TH, Ye MB, et al.

Environ Pollut, 2018 Mar;234:735-742.
PMID: 29245147 DOI: 10.1016/j.envpol.2017.11.100

Sea turtles are globally endangered and face daily anthropogenic threats, including pollution. However, there is a lack of ecotoxicological information on sea turtles, especially in the Asia-Pacific region. This study aims to determine pollutant levels of foraging green turtles (Chelonia mydas) in South China, including Hong Kong, Guangdong and Taiwan, as a basis for their conservation. Scute, liver and muscle tissues of stranded green turtles were analysed for levels of 17 trace elements and methylmercury (MeHg) (n = 86 for scute and n = 14 for liver) and polybrominated diphenyl ethers (PBDEs) (n = 11 for muscle and n = 13 for liver). Ten-fold higher levels of Pb, Ba, V and Tl and 40-fold greater Cd levels were measured in green turtle livers in South China relative to other studies conducted over 10 years ago. Measured PBDE levels were also 27-fold and 50-fold greater than those reported in Australia and Japan. These results warrant further investigation of potential toxicological risks to green turtles in South China and their source rookeries in Malaysia, Micronesia, Indonesia, Marshall Islands, Japan and Taiwan. Research should target monitoring pollutant levels in sea turtles within the West Pacific/Southeast Asia regional management unit spanning East Asia to Southeast Asia to fill in knowledge gaps, in particular in areas such as Thailand, Vietnam, Indonesia, Malaysia and the Philippines where less or no data is available and where foraging grounds of sea turtles have been identified.

Matched MeSH terms: Halogenated Diphenyl Ethers/analysis*
Geographical distribution of non-PBDE-brominated flame retardants in mussels from Asian coastal waters

Isobe T, Ogawa SP, Ramu K, Sudaryanto A, Tanabe S

Environ Sci Pollut Res Int, 2012 Sep;19(8):3107-17.
PMID: 22875421 DOI: 10.1007/s11356-012-0945-6

Hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and decabromodiphenyl ethane (DBDPE) used as alternatives for polybrominated diphenyl ethers (PBDEs) are also persistent in the environment as PBDEs. Limited information on these non-PBDE brominated flame retardants (BFRs) is available; in particular, there are only few publications on environmental pollution by these contaminants in the coastal waters of Asia. In this regard, we investigated the contamination status of HBCDs, BTBPE, and DBDPE in the coastal waters of Asia using mussels as a bioindicator. Concentrations of HBCDs, BTBPE, and DBDPE were determined in green (Perna viridis) and blue mussels (Mytilus edulis) collected from the coastal areas in Cambodia, China (mainland), SAR China (Hong Kong), India, Indonesia, Japan, Malaysia, the Philippines, and Vietnam on 2003-2008. BTBPE and DBDPE were analyzed using GC-MS, whereas HBCDs were determined by LC-MS/MS. HBCDs, BTBPE, and DBDPE were found in mussels at levels ranging from <0.01 to 1,400, <0.1 to 13, and <0.3 to 22 ng/g lipid wt, respectively. Among the three HBCD diastereoisomers, α-HBCD was the dominant isomer followed by γ- and β-HBCDs. Concentrations of HBCDs and DBDPE in mussels from Japan and Korea were higher compared to those from the other Asian countries, indicating extensive usage of these non-PBDE BFRs in Japan and Korea. Higher levels of HBCDs and DBDPE than PBDEs were detected in some mussel samples from Japan. The results suggest that environmental pollution by non-PBDE BFRs, especially HBCDs in Japan, is ubiquitous. This study provides baseline information on the contamination status of these non-PBDE BFRs in the coastal waters of Asia.

Matched MeSH terms: Halogenated Diphenyl Ethers/analysis*
PBDEs in leachates from municipal solid waste dumping sites in tropical Asian countries: phase distribution and debromination

Kwan CS, Takada H, Mizukawa K, Torii M, Koike T, Yamashita R, et al.

Environ Sci Pollut Res Int, 2013 Jun;20(6):4188-204.
PMID: 23247521 DOI: 10.1007/s11356-012-1365-3

Polybrominated diphenyl ethers (PBDEs) are extensively used as flame retardants in many consumer products, and leachates from landfills have been identified as one of the possible sources of PBDEs in the environment. Meanwhile, the unprecedented economic and population growths of some Asian countries over the last decade have led to significant increases in the amount of waste containing PBDEs in that region. This study investigates the status of PBDEs in leachates from municipal solid waste dumping sites (MSWDS) in tropical Asian countries. A total of 46 PBDE congeners were measured, both in the adsorbed (n=24) and dissolved (n=16) phases, in leachate samples collected, from 2002 to 2010, from ten MSWDS distributed among the eight countries of Lao PDR, Cambodia, Vietnam, India, Indonesia, Thailand, the Philippines, and Malaysia. PBDEs were predominantly found in the adsorbed phase. Partitioning of PBDEs in the dissolved phase was associated with the presence of dissolved organic matter; the apparent organic carbon-normalized partition coefficients (K'oc) of the BDE congeners were lower by two to four orders of magnitude than the K oc predicted from the octanol-water partition coefficients (K ow). The total PBDE concentrations from mono- to deca-BDEs ranged from 3.7 to 133,000 ng/L, and showed a trend toward higher concentrations in the more populous and industrialized Asian countries. The congener profiles in the leachates basically reflected the composition of PBDE technical mixtures. The occurrence of congeners not contained, or in trace concentrations, in technical products (e.g., BDEs 208, 207, 206, 202, 188, 179, 49, 17/25, 8, 1) was observed in most of the leachate samples, suggesting the debromination of technical mixtures, including BDE-209, in the MSWDS of tropical Asian countries. Moreover, the temporal trend indicated the reduction of BDE-209 over time, with a corresponding increase in and/or emergence of lower brominated PBDE congeners. The results indicated that MSWDS of tropical Asian countries are potential sources of environmental PBDEs, which may be transported to the aquatic environment via dissolution with dissolved organic matter. MSWDS could be amplifiers of PBDE toxicity in the environment, possibly through debromination.

Matched MeSH terms: Halogenated Diphenyl Ethers/analysis*
A comparative study of sevoflurane sedation with nitrous oxide sedation for dental surgery

Wang CY, Chiu CL, Har KO, Chan C, Rahman ZA

Int J Oral Maxillofac Surg, 2002 Oct;31(5):506-10.
PMID: 12418566

This study compares the use of inhalation sedation using sevoflurane (group S) with inhalation sedation using nitrous oxide (group N) in patients undergoing bilateral extraction of third molar teeth under local anaesthesia. The study was designed as a cross-over study. Seventeen ASA I, day surgery patients were studied. Patients were randomly allocated to receive either 8 l/min 50% nitrous oxide in oxygen (group N) or same flow of 1% sevoflurane (group S) for the first procedure. Each patient then had the alternate method of sedation for the second procedure. There were no significant differences between the methods in patient co-operation and surgeon's satisfaction with sedation. Psychomotor tests were comparable in both groups. The patients were significantly more sedated in the group S compared to group N (P=0.004). Significantly more patients complained of an unpleasant odour group S (P<0.01) but none withdrew from the study for this reason. No adverse cardiorespiratory effects resulted from sevoflurane or nitrous oxide sedation. Both methods gave good amnesia during the procedure. There was high acceptance of both methods and the patients rated the technique as equally satisfactory. We conclude that inhalation sedation with sevoflurane is a suitable alternative method to nitrous oxide sedation.

Matched MeSH terms: Methyl Ethers/administration & dosage*
Fulltext Highly Active Cellulose-Supported Poly(hydroxamic acid)-Cu(II) Complex for Ullmann Etherification

Jian Fui C, Xin Ting T, Sarjadi MS, Amin Z, Sarkar SM, Musta B, et al.

ACS Omega, 2021 Mar 16;6(10):6766-6779.
PMID: 33748590 DOI: 10.1021/acsomega.0c05840

Highly active natural pandanus-extracted cellulose-supported poly(hydroxamic acid)-Cu(II) complex 4 was synthesized. The surface of pandanus cellulose was modified through graft copolymerization using purified methyl acrylate as a monomer. Then, copolymer methyl acrylate was converted into a bidentate chelating ligand poly(hydroxamic acid) via a Loosen rearrangement in the presence of an aqueous solution of hydroxylamine. Finally, copper species were incorporated into poly(hydroxamic acid) via the adsorption process. Cu(II) complex 4 was fully characterized by Fourier transform infrared (FTIR), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The cellulose-supported Cu(II) complex 4 was successfully applied (0.005 mol %) to the Ullmann etherification of aryl, benzyl halides, and phenacyl bromide with a number of aromatic phenols to provide the corresponding ethers with excellent yield [benzyl halide (70-99%); aryl halide (20-90%)]. Cu(II) complex 4 showed high stability and was easily recovered from the reaction mixture. It could be reused up to seven times without loss of its original catalytic activity. Therefore, Cu(II) complex 4 can be commercially utilized for the preparation of various ethers, and this synthetic technique could be a part in the synthesis of natural products and medicinal compounds.

Matched MeSH terms: Ethers

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