In this paper we report alumina based capacitive humidity sensor having exceptional sensing performance in wide range RH segment (10% - 90%). The developed sensor has an improvement of accuracy, reliability, and econo...In this paper we report alumina based capacitive humidity sensor having exceptional sensing performance in wide range RH segment (10% - 90%). The developed sensor has an improvement of accuracy, reliability, and economic efficiency;apart from fast response and recovery time (~s), negligible baseline drift and high selectivity for moisture. The sensing mechanism was discussed based on their microstructures, such as surface area and mesopore volume. In general, at low humidity, surface area and water adsorption play the dominant role, while at high humidity, mesopore volume and capillary condensation become important. Standard characterization techniques such as AFM, FESEM, BET, XRD and impedance spectroscopy were employed for micro-structural and electrical characterization of RH sensor. The nano porous alumina film undergoes a huge change in dielectric upon adsorption of moisture, ensuing large change in capacitance. Additionally, a prototype RH meter has been developed with digital readout for humidity. The interface circuit was based on capacitor-to-duty cycle (CDC) converter. The proposed digital circuit has the advantage of performing adaptive measurements as a function of resolution and bandwidth. The prototype instrument can be used for sub ppm level moisture detection where stability and response are completely unaffected even in highly toxic ambience viz. 4% ammonia and 4% chlorine.展开更多
Sol-gel processed alumina(Al_(2)O_(3))thin film has been investigated for sensing moisture.The sensor was based on ordered nanoporous Al_(2)O_(3)thin film,which consisted of gold electrodes on both sides of the film f...Sol-gel processed alumina(Al_(2)O_(3))thin film has been investigated for sensing moisture.The sensor was based on ordered nanoporous Al_(2)O_(3)thin film,which consisted of gold electrodes on both sides of the film forming parallel plate capacitor.Alumina substrate was used for supporting thin film moisture sensor.Hydrophilicity was achieved by controlling the surface energy of the substrate and polymer(polyvinyl alcohol(PVA))optimization was done for developing rigid thin film over it.A high change in capacitance was observed as the moisture level increased from 5 ppmV to 500 ppmV.Scanning electron microscopy(SEM)results revealed that pores were distributed uniformly throughout the sample,which enhanced the adsorption of water molecule over the film.X-ray diffraction(XRD)study clearly confirmed the gamma(γ)phase of alumina thin film.It was found that the sensitivity of our sensor was suitable for commercial application.展开更多
Background:In the early metastasis of colon cancer,cancer cells detach,migrate,and infiltrate surrounding tissues,including lymph vessels and blood vessels.Tumor heterogeneity arises from both tumor cells and distinct...Background:In the early metastasis of colon cancer,cancer cells detach,migrate,and infiltrate surrounding tissues,including lymph vessels and blood vessels.Tumor heterogeneity arises from both tumor cells and distinct microenvironments.Maldistribution of blood vessels,creates hypoxic regions within the tumors,fostering cancer stem cell-like properties due to reduced oxygen and nutrient supply.Under hypoxia,tumor cells shift to a glycolytic pathway,producing more lactic acid that acidifies the microenvironment and leads to unstable heart rate variability(HRV)factors,weight disparity,and a higher incidence of aberrant crypt foci(ACF).These hypoxic-induced parameters promote cancer cell invasion,increase radiation resistance,and facilitate cancer cell migration.Methods:In this study,we induced hypoxia-preneoplastic colon damage in albino Wister rats by administrating 1,2-dimethyl hydrazine(DMH).After successfully creating a hypoxic environment in albino Wister rats,resulting in preneoplastic colon damage,we randomly allocated Wistar albino rats into seven groups,each containing 8 animals,and conducted a 6-week study.Group 1-Normal control(administered 1 mM EDTA+saline,2 ml/kg/day,p.o.);group 2-Toxic control(administered DMH,30 mg/kg/week,s.c.);group 3-Standard treatment(DMH,30 mg/kg/week,s.c.for 6 weeks),followed by 5-fluorouracil and Leucovorin(25 mg/kg each on 1^(st),3^(rd),7^(th),and 10^(th) days,i.p.after 6 weeks administration of DMH);group 4-Low dose of P1(DMH,30 mg/kg/week,s.c.+P1,2 mg/kg,i.v.,weekly for 3 weeks);group 5-High dose P1(DMH,30 mg/kg/week,s.c.+P1,4 mg/kg,i.v.,weekly for 3 weeks),group 6-Low dose of P2(DMH,30 mg/kg/week,s.c.,+P2,2 mg/kg,i.v.,weekly for 3 weeks),group 7-High dose of P2(DMH,30 mg/kg/week,s.c.,+P2,4 mg/kg,i.v.weekly for 3 weeks).Results:DMH-treated rats exhibited alterations in HRV factors,weight disparity,elevated gastric pH,increased total acidity,a higher incidence of ACF,and changes in antioxidant markers(TBARs,SOD,catalase,GSH).Brightfield microscopy at 40x magnification revealed the presence of large crypts within aberrant crypt foci in the toxic control group.Conclusion:Treatment groups P1 and P2 containing triazine derivatives initiated proteasomal degradation of Hypoxia Inducible Factor-1α(HIF-1α)by activating Prolyl Hydroxylase(PHDs)pathways.HIF-1αunder a hypoxic environment is responsible for activating a multitude of genes involved in angiogenesis,metastasis,invasiveness,pH changes,metabolic reprogramming,stem cell maintenance,resistance to radiation,and downstream regulation of the immune system.Treatment with P1 and P2 groups helped minimize the ACF count and restored HRV factors,weight disparity,pH levels,total acidity,and oxidative balance.Our findings emphasize the potential role of 1,2,4-triazine derivatives in suppressing hypoxia-induced colon carcinogenesis.展开更多
文摘In this paper we report alumina based capacitive humidity sensor having exceptional sensing performance in wide range RH segment (10% - 90%). The developed sensor has an improvement of accuracy, reliability, and economic efficiency;apart from fast response and recovery time (~s), negligible baseline drift and high selectivity for moisture. The sensing mechanism was discussed based on their microstructures, such as surface area and mesopore volume. In general, at low humidity, surface area and water adsorption play the dominant role, while at high humidity, mesopore volume and capillary condensation become important. Standard characterization techniques such as AFM, FESEM, BET, XRD and impedance spectroscopy were employed for micro-structural and electrical characterization of RH sensor. The nano porous alumina film undergoes a huge change in dielectric upon adsorption of moisture, ensuing large change in capacitance. Additionally, a prototype RH meter has been developed with digital readout for humidity. The interface circuit was based on capacitor-to-duty cycle (CDC) converter. The proposed digital circuit has the advantage of performing adaptive measurements as a function of resolution and bandwidth. The prototype instrument can be used for sub ppm level moisture detection where stability and response are completely unaffected even in highly toxic ambience viz. 4% ammonia and 4% chlorine.
文摘Sol-gel processed alumina(Al_(2)O_(3))thin film has been investigated for sensing moisture.The sensor was based on ordered nanoporous Al_(2)O_(3)thin film,which consisted of gold electrodes on both sides of the film forming parallel plate capacitor.Alumina substrate was used for supporting thin film moisture sensor.Hydrophilicity was achieved by controlling the surface energy of the substrate and polymer(polyvinyl alcohol(PVA))optimization was done for developing rigid thin film over it.A high change in capacitance was observed as the moisture level increased from 5 ppmV to 500 ppmV.Scanning electron microscopy(SEM)results revealed that pores were distributed uniformly throughout the sample,which enhanced the adsorption of water molecule over the film.X-ray diffraction(XRD)study clearly confirmed the gamma(γ)phase of alumina thin film.It was found that the sensitivity of our sensor was suitable for commercial application.
基金C.Karthikeyan,Indira Gandhi National Tribal University,Lalpur,Amarkantak,Anuppur,Madhya Pradesh,484887,India,for providing the gift sample of 1,2,4-triazine derivatives used for the study.
文摘Background:In the early metastasis of colon cancer,cancer cells detach,migrate,and infiltrate surrounding tissues,including lymph vessels and blood vessels.Tumor heterogeneity arises from both tumor cells and distinct microenvironments.Maldistribution of blood vessels,creates hypoxic regions within the tumors,fostering cancer stem cell-like properties due to reduced oxygen and nutrient supply.Under hypoxia,tumor cells shift to a glycolytic pathway,producing more lactic acid that acidifies the microenvironment and leads to unstable heart rate variability(HRV)factors,weight disparity,and a higher incidence of aberrant crypt foci(ACF).These hypoxic-induced parameters promote cancer cell invasion,increase radiation resistance,and facilitate cancer cell migration.Methods:In this study,we induced hypoxia-preneoplastic colon damage in albino Wister rats by administrating 1,2-dimethyl hydrazine(DMH).After successfully creating a hypoxic environment in albino Wister rats,resulting in preneoplastic colon damage,we randomly allocated Wistar albino rats into seven groups,each containing 8 animals,and conducted a 6-week study.Group 1-Normal control(administered 1 mM EDTA+saline,2 ml/kg/day,p.o.);group 2-Toxic control(administered DMH,30 mg/kg/week,s.c.);group 3-Standard treatment(DMH,30 mg/kg/week,s.c.for 6 weeks),followed by 5-fluorouracil and Leucovorin(25 mg/kg each on 1^(st),3^(rd),7^(th),and 10^(th) days,i.p.after 6 weeks administration of DMH);group 4-Low dose of P1(DMH,30 mg/kg/week,s.c.+P1,2 mg/kg,i.v.,weekly for 3 weeks);group 5-High dose P1(DMH,30 mg/kg/week,s.c.+P1,4 mg/kg,i.v.,weekly for 3 weeks),group 6-Low dose of P2(DMH,30 mg/kg/week,s.c.,+P2,2 mg/kg,i.v.,weekly for 3 weeks),group 7-High dose of P2(DMH,30 mg/kg/week,s.c.,+P2,4 mg/kg,i.v.weekly for 3 weeks).Results:DMH-treated rats exhibited alterations in HRV factors,weight disparity,elevated gastric pH,increased total acidity,a higher incidence of ACF,and changes in antioxidant markers(TBARs,SOD,catalase,GSH).Brightfield microscopy at 40x magnification revealed the presence of large crypts within aberrant crypt foci in the toxic control group.Conclusion:Treatment groups P1 and P2 containing triazine derivatives initiated proteasomal degradation of Hypoxia Inducible Factor-1α(HIF-1α)by activating Prolyl Hydroxylase(PHDs)pathways.HIF-1αunder a hypoxic environment is responsible for activating a multitude of genes involved in angiogenesis,metastasis,invasiveness,pH changes,metabolic reprogramming,stem cell maintenance,resistance to radiation,and downstream regulation of the immune system.Treatment with P1 and P2 groups helped minimize the ACF count and restored HRV factors,weight disparity,pH levels,total acidity,and oxidative balance.Our findings emphasize the potential role of 1,2,4-triazine derivatives in suppressing hypoxia-induced colon carcinogenesis.
