Chlorophenols, typically 4-chlorophenols are highly toxic and non-biodegradable organic contaminants which pose serious threat to the environment, particularly when released into aqueous medium. The removal of these p...Chlorophenols, typically 4-chlorophenols are highly toxic and non-biodegradable organic contaminants which pose serious threat to the environment, particularly when released into aqueous medium. The removal of these pollutants by efficient method has received worldwide concern in recent past. A new Fe3O4–Cr2O3 magnetic nanocomposite was synthesized by wet chemical method under ultrasonic irradiation. Microstructure and morphology of the nanocomposite were characterized by powder X-ray diffraction（XRD）,Fourier transform infrared（FT-IR）, and a transmission electron microscope（TEM）. Magnetic and optical properties were studied by a vibrating sample magnetometer（VSM） and an ultraviolet–visible（UV–Vis） spectrophotometer respectively. The magnetic nanocomposite（MNC） was used as photocatalyst for effective decomposition of 4-chlorophenol in water under ultraviolet（UV） irradiation.展开更多
Nutrient recovery from source-separated human urine has attracted interest as it is rich in nitrogen and phosphorus that can be utilized as fertilizer.However,urine also contains pharmaceuticals,steroid hormones,etc.a...Nutrient recovery from source-separated human urine has attracted interest as it is rich in nitrogen and phosphorus that can be utilized as fertilizer.However,urine also contains pharmaceuticals,steroid hormones,etc.and their removal is crucial as they have detrimental effects on the environment and human health.The current study focuses on investigating the degradation of pharmaceuticals using a double-chamber microbial fuel cell(MFC).Urine was spiked with four pharmaceuticals(trimethoprim,lamivudine,levofloxacin,and estrone)at a concentration of 2 mg/mL.The MFC was operated for 7 months in batch mode with this spiked urine as feed.The degradation efficiency of the MFC was studied,for which a selective liquid chromatography-tandem mass-spectrometric method was developed for the quantitation of compounds used in the spiking experiments and was validated with a lower limit of quantification of 0.39 ng/mL.The maximum removal rate achieved was 96%±2%.The degradation mechanism involved processes like sorption and anoxic biodegradation.The voltage curve obtained showed that the presence of pharmaceuticals had an initial negative impact on power generation along with increased organic content;however,after the reactor acclimatization,increased power output was achieved with maximum organics removal at 30 h of retention time.This work opens a new perspective for the anoxic biodegradation of pharmaceuticals and can be useful in future bioremediation studies.展开更多
AIM:To access the association of forty-eight single nucleotide polymorphisms(SNPs)identified from Caucasian population with steroid-induced ocular hypertension(OHT)in India population.METHODS:Fifty-four triamcinolone-...AIM:To access the association of forty-eight single nucleotide polymorphisms(SNPs)identified from Caucasian population with steroid-induced ocular hypertension(OHT)in India population.METHODS:Fifty-four triamcinolone-acetonide(TA)and for ty-seven dexamethasone(Dex)administered subjects were enrolled in the study after a written consent.Intraocular pressure(IOP)values were recorded for a period of 6-month post steroid injections and patients were grouped as steroid-responders(SR:IOP≥21 mm Hg)and non-responders(NR:IOP≤20 mm Hg).Genomic DNA was isolated from peripheral venous blood.Forty-eight SNPs identified in TA treated Caucasian patients by genome wide association study(GWAS)were genotyped using iPLEXTM MassA RRAY among TA as well as Dex administered Indian patients.Genotyping data of 48 general subjects from a previous study were considered as reference controls for statistical analysis.Genotypic frequencies were calculated and P-value,Chi-square and odds ratio at 95%confidenceinterval of group A(steroid treated vs controls),group B(SR vs NR),group C(phenotype correlation:influence of time,severity and gender on IOP rise),were calculated.P<0.05 was considered to be statistically significant.RESULTS:OHT was observed in 50%of TA and 26%of Dex administered patients,respectively.IOP rise was mostly severe(>30 mm Hg)and immediate(<1 wk)among TA-SR patients while it was noticed to be mild(<30 mm Hg)and between 1-2 mo among Dex-SR patients.Logistic regression for risk factor correlation with OHT remained non-significant,hence these factors were not considered as confounding parameters for further analysis.rs133,rs34016742,rs274554,rs10936746,rs274547,rs804854,rs7751500,rs359498,and rs7547448 SNPs significantly varied even after Bonferroni corrections(P<0.0025;group A).rs1879370(TA)and rs6559662(Dex)were significantly(P<0.05)associated with OHT(group B).rs133(severe IOP rise),rs11047639 and rs1879370(male gender),and rs11171569(immediate IOP rise)significantly(P<0.05)influenced the phenotype correlation only among TAOHT patients.However,the significance of these SNPs in group B and phenotype analysis(group C)was lost upon Bonferroni corrections(P<0.0025).CONCLUSION:Prevalence of OHT in study population is observed to be similar to other studies both in TA and Dex treated patients.We can correlate rs34016742 involved in diabetes signaling pathway to the occurrence of ocular edematous and inflammatory conditions.Except rs133 that is involved in neuro-degeneration and myopia occurrence,none of the other SNPs identified in Caucasian population possess any correlation with OHT incidence in TA and Dex administered Indian subjects.展开更多
The chemical electrolytes are widely used in electrochemical machining(ECM)and have a significant effect on both the material removal rate(MRR)and the surface finish(Ra)of the workpiece.The process parameters of ECM,s...The chemical electrolytes are widely used in electrochemical machining(ECM)and have a significant effect on both the material removal rate(MRR)and the surface finish(Ra)of the workpiece.The process parameters of ECM,such as current density,electrolyte composition,and feed rate,are vital for optimizing machining performance.Research has indicated that high current density can create localized non-conductive passivating films,which impede metal dissolution.In this study,the aqueous solution of sodium nitrate(NaNO_(3))combined with gold nanoparticles(AuNPs)has been used as a novel electrolyte to evaluate the machining performance of the 20MnCr5 steel alloy.The inclusion of AuNPs in the NaNO_(3) solution enhanced local surface effects and promoted low-valence metal dissolution.The results demonstrated that the MRR and average surface roughness of the 20MnCr5 workpiece improved by 19.6%and 35.5%,respectively,when AuNPs were utilized compared to the alone NaNO_(3) electrolytic system.The experimental results also showed that the MRR increased within the current density range of 5.5 A/cm^(2) to 15.8 A/cm^(2),but declined in the range of 15.8 A/cm^(2) to 32.5 A/cm^(2).This decrease in the MRR at higher current densities can be attributed to the formation of non-conductive metal oxide passive layers.The oxygen evolution reaction(OER)was observed with the NaNO_(3) electrolyte at higher current densities,resulting in the formation of numerous micropores on the surface of the workpiece.In contrast,when the electrolyte was combined with AuNPs,these micropores ruptured quickly,creating new sites for the re-dissolution of metal ions.The microstructural changes on the machining surfaces under different operating conditions were analyzed using field emission scanning electron microscopy(FESEM),and the results are presented.Possible surface reactions,such as the formation of metal oxides and the release of oxygen gas,are discussed based on energy-dispersive X-ray(EDX)analysis and cyclic voltammetry(CV)studies.展开更多
基金support from Central Instruments Facility and Department of Chemistry of Indian Institute of Technology Guwahati for extending various analytical facilities during the course of investigation
文摘Chlorophenols, typically 4-chlorophenols are highly toxic and non-biodegradable organic contaminants which pose serious threat to the environment, particularly when released into aqueous medium. The removal of these pollutants by efficient method has received worldwide concern in recent past. A new Fe3O4–Cr2O3 magnetic nanocomposite was synthesized by wet chemical method under ultrasonic irradiation. Microstructure and morphology of the nanocomposite were characterized by powder X-ray diffraction（XRD）,Fourier transform infrared（FT-IR）, and a transmission electron microscope（TEM）. Magnetic and optical properties were studied by a vibrating sample magnetometer（VSM） and an ultraviolet–visible（UV–Vis） spectrophotometer respectively. The magnetic nanocomposite（MNC） was used as photocatalyst for effective decomposition of 4-chlorophenol in water under ultraviolet（UV） irradiation.
文摘Nutrient recovery from source-separated human urine has attracted interest as it is rich in nitrogen and phosphorus that can be utilized as fertilizer.However,urine also contains pharmaceuticals,steroid hormones,etc.and their removal is crucial as they have detrimental effects on the environment and human health.The current study focuses on investigating the degradation of pharmaceuticals using a double-chamber microbial fuel cell(MFC).Urine was spiked with four pharmaceuticals(trimethoprim,lamivudine,levofloxacin,and estrone)at a concentration of 2 mg/mL.The MFC was operated for 7 months in batch mode with this spiked urine as feed.The degradation efficiency of the MFC was studied,for which a selective liquid chromatography-tandem mass-spectrometric method was developed for the quantitation of compounds used in the spiking experiments and was validated with a lower limit of quantification of 0.39 ng/mL.The maximum removal rate achieved was 96%±2%.The degradation mechanism involved processes like sorption and anoxic biodegradation.The voltage curve obtained showed that the presence of pharmaceuticals had an initial negative impact on power generation along with increased organic content;however,after the reactor acclimatization,increased power output was achieved with maximum organics removal at 30 h of retention time.This work opens a new perspective for the anoxic biodegradation of pharmaceuticals and can be useful in future bioremediation studies.
基金Supported by equally the Department of Biotechnology under the grant(No.BT/PR3580/PID/6/625/2011)Indian Council of Medical Research(ICMR)under grant[No.82/19/2012/PHGEN(TF)/BMS]。
文摘AIM:To access the association of forty-eight single nucleotide polymorphisms(SNPs)identified from Caucasian population with steroid-induced ocular hypertension(OHT)in India population.METHODS:Fifty-four triamcinolone-acetonide(TA)and for ty-seven dexamethasone(Dex)administered subjects were enrolled in the study after a written consent.Intraocular pressure(IOP)values were recorded for a period of 6-month post steroid injections and patients were grouped as steroid-responders(SR:IOP≥21 mm Hg)and non-responders(NR:IOP≤20 mm Hg).Genomic DNA was isolated from peripheral venous blood.Forty-eight SNPs identified in TA treated Caucasian patients by genome wide association study(GWAS)were genotyped using iPLEXTM MassA RRAY among TA as well as Dex administered Indian patients.Genotyping data of 48 general subjects from a previous study were considered as reference controls for statistical analysis.Genotypic frequencies were calculated and P-value,Chi-square and odds ratio at 95%confidenceinterval of group A(steroid treated vs controls),group B(SR vs NR),group C(phenotype correlation:influence of time,severity and gender on IOP rise),were calculated.P<0.05 was considered to be statistically significant.RESULTS:OHT was observed in 50%of TA and 26%of Dex administered patients,respectively.IOP rise was mostly severe(>30 mm Hg)and immediate(<1 wk)among TA-SR patients while it was noticed to be mild(<30 mm Hg)and between 1-2 mo among Dex-SR patients.Logistic regression for risk factor correlation with OHT remained non-significant,hence these factors were not considered as confounding parameters for further analysis.rs133,rs34016742,rs274554,rs10936746,rs274547,rs804854,rs7751500,rs359498,and rs7547448 SNPs significantly varied even after Bonferroni corrections(P<0.0025;group A).rs1879370(TA)and rs6559662(Dex)were significantly(P<0.05)associated with OHT(group B).rs133(severe IOP rise),rs11047639 and rs1879370(male gender),and rs11171569(immediate IOP rise)significantly(P<0.05)influenced the phenotype correlation only among TAOHT patients.However,the significance of these SNPs in group B and phenotype analysis(group C)was lost upon Bonferroni corrections(P<0.0025).CONCLUSION:Prevalence of OHT in study population is observed to be similar to other studies both in TA and Dex treated patients.We can correlate rs34016742 involved in diabetes signaling pathway to the occurrence of ocular edematous and inflammatory conditions.Except rs133 that is involved in neuro-degeneration and myopia occurrence,none of the other SNPs identified in Caucasian population possess any correlation with OHT incidence in TA and Dex administered Indian subjects.
文摘The chemical electrolytes are widely used in electrochemical machining(ECM)and have a significant effect on both the material removal rate(MRR)and the surface finish(Ra)of the workpiece.The process parameters of ECM,such as current density,electrolyte composition,and feed rate,are vital for optimizing machining performance.Research has indicated that high current density can create localized non-conductive passivating films,which impede metal dissolution.In this study,the aqueous solution of sodium nitrate(NaNO_(3))combined with gold nanoparticles(AuNPs)has been used as a novel electrolyte to evaluate the machining performance of the 20MnCr5 steel alloy.The inclusion of AuNPs in the NaNO_(3) solution enhanced local surface effects and promoted low-valence metal dissolution.The results demonstrated that the MRR and average surface roughness of the 20MnCr5 workpiece improved by 19.6%and 35.5%,respectively,when AuNPs were utilized compared to the alone NaNO_(3) electrolytic system.The experimental results also showed that the MRR increased within the current density range of 5.5 A/cm^(2) to 15.8 A/cm^(2),but declined in the range of 15.8 A/cm^(2) to 32.5 A/cm^(2).This decrease in the MRR at higher current densities can be attributed to the formation of non-conductive metal oxide passive layers.The oxygen evolution reaction(OER)was observed with the NaNO_(3) electrolyte at higher current densities,resulting in the formation of numerous micropores on the surface of the workpiece.In contrast,when the electrolyte was combined with AuNPs,these micropores ruptured quickly,creating new sites for the re-dissolution of metal ions.The microstructural changes on the machining surfaces under different operating conditions were analyzed using field emission scanning electron microscopy(FESEM),and the results are presented.Possible surface reactions,such as the formation of metal oxides and the release of oxygen gas,are discussed based on energy-dispersive X-ray(EDX)analysis and cyclic voltammetry(CV)studies.
