The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-b...The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.展开更多
Objective:Acorus calamus(AC)L.(Araceae)is an annual semi-aquatic and aromatic plant found in Europe,North America and Asia.Its rhizomes are often used by Native Americans,Americans,and Chinese as well as by other cult...Objective:Acorus calamus(AC)L.(Araceae)is an annual semi-aquatic and aromatic plant found in Europe,North America and Asia.Its rhizomes are often used by Native Americans,Americans,and Chinese as well as by other cultures.Ethnobotanical studies and documents have shown their use in various disease treatments,such as insomnia,mental disorders,diabetes mellitus,epilepsy,inflammation,asthma,neuropathic pain,and diarrhea.In this study,the antidepressant activity of methanolic and hydroalcoholic extracts of the AC rhizome part in mice was investigated.Methods:Three doses of methanolic extract of AC rhizome(MEACR)(25,50 and 100 mg/kg b.wt),three doses of hydroalcoholic extract of AC rhizome(HAACR)(100,200 and 400 mg/kg b.wt),and standards(imipramine,15 mg/kg b.wt and fluoxetine,20 mg/kg b.wt)was daily oral administration to the mice for consecutive 14 days.The extract effect on the immobility time was monitored by a tail suspension test(TST)and a forced swimming test(FST).Monoamine oxidase(MAO)levels were also analyzed using standard methods.Results:The optimum antidepressant activity was viewed at 100 mg/kg b.wt of MEACR extract and400 mg/kg b.wt of HAACR extract with 23.82%and 20.59%immobility period reduction,respectively.Besides,the extracts weakened the FST-induced elevation of MAO activity significantly and returned to near-normal levels of neurotransmitters in the brain.100 mg/kg b.wt or above of MEACR extract significantly prevented the MAO-A and MAO-B activities in mice brain at a dose-dependent fashion.But,just 400 mg/kg b.wt of HAACR extract prevented the activity of MAO-A and MAO-B.Fluoxetine and imipramine showed a tendency to prevent the activity of MAO-A and MAO-B.Conclusion:This study suggests that AC rhizome extract mediated antidepressant activity by modulating the central neurochemical and hypothalamic-pituitary-adrenal(HPA)axis in response to FST and TSTinduced stress.Therefore,AC rhizome extract can be used as a valuable plant supplement to treat depressive disorders.展开更多
This study investigated <i>Bacillus subtilis</i> ATCC13952 as an adsorbent for arsenic in groundwater. Batch experiments were used to determine the effect of contact time, adsorbent dose, arsenic (III) con...This study investigated <i>Bacillus subtilis</i> ATCC13952 as an adsorbent for arsenic in groundwater. Batch experiments were used to determine the effect of contact time, adsorbent dose, arsenic (III) concentration, pH, and temperature on the process. The percentage of arsenic (III) removed was high at a contact time of four days, 3.0 mL of <i>Bacillus subtilis</i> ATCC13952, pH 8 and temperature of 35°C. The kinetics of the process showed the Elovich kinetics model as the best fit for the process. This indicates that arsenic removal was by chemisorption. The analysis of the nonlinear equilibrium isotherms and the error functions showed the Langmuir isotherm as best fit for the process. Mechanistic study of the process indicated bulk diffusion to be the rate-determining step. Thermodynamically, the process was favourable, spontaneous and feasible. When the community water samples were treated with the <i>Bacillus subtilis</i> ATCC13952 at the optimum contact time, adsorbent dose, pH and temperature, 99.96% - 99.97% of arsenic was removed across all sampling points within the studied communities. Hence, the results show that <i>Bacillus subtilis</i> ATCC13952 is an efficient adsorbent for arsenic in aqueous systems and the organism appears to hold the key to purging the environment of arsenic contamination.展开更多
Au/n-Si （MS） structures with a high dielectric interlayer （0.03 graphene-doped PVA） are fabricated to investigate the illumination and voltage effects on electrical and dielectric properties by using capacitance-v...Au/n-Si （MS） structures with a high dielectric interlayer （0.03 graphene-doped PVA） are fabricated to investigate the illumination and voltage effects on electrical and dielectric properties by using capacitance-voltage （C-V） and conductance-voltage （G/w-V） measurements at room temperature and at 1 MHz. Some of the main electrical parameters such as concentration of doping atoms （ND）, barrier height （ ФB（ C - V） ）, depletion layer width （WD） and series resistance （Rs） show fairly large illumination dispersion. The voltage-dependent profile of surface states （Nss） and resistance of the structure （Ri ） are also obtained by using the dark-illumination capacitance （Cdark- Cm） and Nicollian-Brews methods, respectively, For a clear observation of changes in electrical parameters with illumination, the values of ND, WD, ФB（O- V） and Rs are drawn as a function of illumination intensity. The values of ND and WD change almost linearly with illumination intensity. On the other hand, Rs decreases almost exponentially with increasing illumination intensity whereas ФB（C - V） increases. The experimental results suggest that the use of a high dielectric interlayer （0.03 graphene-doped PVA） considerably passivates or reduces the magnitude of the surface states. The large change or dispersion in main electrical parameters can be attributed to generation of electron-hole pairs in the junction under illumination and to a good light absorption. All of these experimental results confirm that the fabricated Au/0.03 graphene-doped PVA/n-Si structure can be used as a photodiode or a capacitor in optoelectronic applications.展开更多
The purpose of this research was to fmd out effectiveness of chloride solid membrane electrode of coated wire system compared to solid membrane electrode of composite system, the Nernstian response and character＇s po...The purpose of this research was to fmd out effectiveness of chloride solid membrane electrode of coated wire system compared to solid membrane electrode of composite system, the Nernstian response and character＇s potential response （detection limit, selectivity and response time）. The chloride ISEs （ion selective electrodes） in this research were the solid membrane chloride ISEs based AgC1. There were two types of chloride ISEs that were developed, namely the chloride ISEs of coated wire and composite systems. Both types of electrodes were characterized. The selectivity was done by comparing Esel of the chloride standard solutions and Esel of the interference ions （Br- and I-）. The measurement of chloride ions in water samples was done by using the coated wire chloride ISE, the composite chloride ISE and the Mohr method. We compared the result of the two chloride ISE methods to that of standard method for chloride determination （Mohr） by using F-test and Post Hoc Test LSD （least significant difference） and Duncan. Analysis by using F-test and Post Hoc Test （LSD and Duncan） and characterization results of both the methods showed that coated wire chloride ISE was more effective compared to composite chloride ISE. Nemstian response was 59.83 mV/decade, linier range measurement was 10-1-10-5 M, limit detection was 1.23 × 10-5 M, response time along was 25 s and interfering ion was 10-4 M Br-.展开更多
Chemical tests were carried out on the aqueous extracts of the air-dried powders of two tropical moss plants, Thidium gratum and Barbula indica using standard procedures, to identify the phytochemical constituents. Th...Chemical tests were carried out on the aqueous extracts of the air-dried powders of two tropical moss plants, Thidium gratum and Barbula indica using standard procedures, to identify the phytochemical constituents. The extracts were screened for the presence and quantities of alkaloids, flavonoids, phenols, saponins and steroids with a view to assess their therapeutic values in ethnomedicine. The results of the phytochemical screening revealed the presence of alkaloids, flavonoids, phenols, saponins and steroids in varying quantities in the two moss plants but there was absence of phenol in Barbula indica. These results suggest that the two moss plants can be veritable and potential source of useful drugs in treatment of ailments.展开更多
This study aims to investigate the antibacterial activities of essential oils isolated from various parts (buds, leaves and stems) of Eugenia caryophylata. The essentials oils were distillated by steam distillation, a...This study aims to investigate the antibacterial activities of essential oils isolated from various parts (buds, leaves and stems) of Eugenia caryophylata. The essentials oils were distillated by steam distillation, and the isolated was analyzed by GC and GC-MS. Five components of each sample of oils (buds, leaves and stems) were identified. Main component in the bud are eugenol (75.30%), eugenyl acetate (20.93%) and β-caryophyllene (3.00%) and eugenol (82.97%), β-caryophyllene (12.84%) in leaf oil, while in stem oil eugenol (97.75%). The oils were tested for in vitro antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), the Gram-negative bacteria (Escherichia coli and Salmonella typhimurium). The essential oils of bud, leaf and stem oil show that antibacterial activity against Gram-positive and Gram-negative bacteria.展开更多
Road runoffs were sampled from five highways and five urban roads located in the New Juaben Municipality during the late storm events in the month of November 2014 and the early storm events in January 2015. A variety...Road runoffs were sampled from five highways and five urban roads located in the New Juaben Municipality during the late storm events in the month of November 2014 and the early storm events in January 2015. A variety of water quality parameters such as, pH, temperature, turbidity, electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), aqueous concentrations of Chloride (Cl<sup>-</sup>), Phosphate (), Nitrate () and Sulphate () ions as well as the total concentrations of some selected heavy metals (Fe, Cu, Zn, Pb, Cd, Ni and Cr) were analysed for both periods. Although the results for the studied parameters, particularly the heavy metals varied for both sampling periods, the general trend indicated an increase in accumulation from November 2014 to January 2015. This was attributed to vehicular deposition as well as other natural and anthropogenic depositions on the road surfaces during the antecedent dry weather period between the two sampling months. The highest increase in pollutant loadings was associated with the heavy metals and some physico-chemical parameters such as TSS, TDS, EC and turbidity. Generally, EC, TDS, TSS and turbidity were above the permissible limits of the Environmental Protection Agency (EPA) of Ghana for both sampling periods. However, almost all the mean concentrations of heavy metals recorded for both road runoffs and the control samples were within the permissible limits of the Ghana EPA with some few exceptions.展开更多
Prostate cancer(PC)biomarker-citrate detection is clinically important to diagnose PC in early stages.Methylquinolinium iodide(Q)conjugated indole-phenylboronic acid(IB)was designed as a red-emissive QIB probe for the...Prostate cancer(PC)biomarker-citrate detection is clinically important to diagnose PC in early stages.Methylquinolinium iodide(Q)conjugated indole-phenylboronic acid(IB)was designed as a red-emissive QIB probe for the detection of citrate through Lewis acid-base reaction and intramolecular charge transfer(ICT)sensing mechanisms.Boronic acid acts as Lewis acid as well as citrate(Lewis base)recognition unit.The probe reacted with citrate,showing enhanced red emissions.Since the probe has excellent water solubility and great biocompatibility,practical application in biological systems is possible.Citrate was monitored precisely in the mitochondria organelle(in vitro)of living cells with a positive charge on QIB.Also,endogenous(in situ)citrate was detected quantitatively to discriminate non-cancerous and PC mice,observed strong and lower(negligible)emission intensity on non-cancerous and cancerous prostate tissues,respectively.Because,the concentration of citrate is higher in healthy prostate compared with PC prostate.Furthermore,the analysis of sliced prostate tissues can give PC-related information for clinical diagnosis to prevent and treat PC in the initial stages.Therefore,we believe that the present probe is a promising biochemical reagent in diagnosing PC.展开更多
Photoelectrochemical(PEC)water splitting is regarded as the most promising method to generate“green hydrogen”,and zinc oxide(ZnO)has been identified as one of the promising candidates for PEC water splitting owing t...Photoelectrochemical(PEC)water splitting is regarded as the most promising method to generate“green hydrogen”,and zinc oxide(ZnO)has been identified as one of the promising candidates for PEC water splitting owing to its straddling band alignment with the water redox level.However,its PEC performance is limited due to its wide bandgap and anticipated by photocorrosion in an aqueous medium.In this work,we present strategic improvements in the PEC water splitting performance of ZnO nanowires(NWs)by nitrogen(N)-doping along with photostability by the core–shell deposition of a NiOOH cocatalyst.Highly crystalline hierarchical ZnO NWs were fabricated on Si NWs(ZnO-Si HNWs)using a metal organic chemical vapor deposition approach.The NWs were then N-doped by annealing in an NH_(3) atmosphere.The N-doped ZnO-Si HNWs(N:ZnO-Si HNWs)showed enhanced visible light absorption,and suppressed recombination of the photogenerated carriers.As compared to ZnO-Si HNWs(0.045 m A cm^(-2) at 1.23 V vs RHE),the N:ZnO-Si HNWs(0.34 m A cm^(-2) at 1.23 V vs RHE)annealed in NH^(3) ambient for 3 h at 600℃showed 7.5-fold enhancement in the photocurrent density.NiOOH-deposited N:ZnO-Si HNW photoanodes with a photostability of 82.21%over 20000 s showed 10.69-fold higher photocurrent density(0.48 m A cm^(-2) at 1.23 V vs RHE)than ZnO-Si HNWs.展开更多
Silver nanoparticles have provided considerable interest because of their potential applications in areas such as for fighting against all types of diseases, whether caused by germs, viruses, bacteria, allergens or pa...Silver nanoparticles have provided considerable interest because of their potential applications in areas such as for fighting against all types of diseases, whether caused by germs, viruses, bacteria, allergens or pathogens. At the same time, silver nanoparticles have attracted considerable concern because of their potential applications in areas such as surface enhanced Raman scattering, nanoelectronics, optical filters, and electromagnetic interference shielding. [1, 2]展开更多
Introduction: The mining industry ranks among the most hazardous occupations globally owing to the high prevalence of workplace accidents. To better protect workers in the industry, there is a need for a comprehensive...Introduction: The mining industry ranks among the most hazardous occupations globally owing to the high prevalence of workplace accidents. To better protect workers in the industry, there is a need for a comprehensive understanding of risk factors, common illnesses and provision of PPE. Objective: This study examined the prevalence and underlying risk factors to work-related injuries, common illnesses, and Personal Protective Equipment (PPE) usage among mineworkers in two large-scale mining companies in Ghana that consented to participation. Methodology: Two hundred mineworkers were selected through stratified sampling in these companies using a semi-structured questionnaire. Chi-square test and binomial logistic regression were employed to determine the relationship between the incidence of occupational injury and selected risk factors using R studio. Results: The results showed that more than a tenth (16%;n = 31) of mineworkers had sustained physical injuries since being employed—mostly lacerations (53%). Out of those injured, (85%;n = 22) reportedly sustain an injury annually. A little more than half (57%;n = 112) of the mineworkers work for more than 40 hours per week. Injuries were significantly associated with the type of profession at the mine (p = 0.04;χ<sup>2</sup> = 4.3)—Technicians and Mechanics were more likely to be injured. Although not statistically significant, working for more than 40 hours/week doubled the odds of being injured at the workplace (aOR = 1.77;95% CI: -0.27 - 1.48). The topmost illnesses among mineworkers were musculoskeletal pains (MSPs) [53%] and headaches (35%). About two-thirds (65%) had all the needed PPEs for their work. Safety goggles were the predominant PPE reportedly lacking among the mineworkers (16%;n = 31). Conclusion: There is a need for targeted training/intervention programmes and adoption of assistive ergonomic devices to protect mineworkers.展开更多
Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive ra...Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive range for biomedical application.However,a deep understanding of the role of the C-N configuration in the CDs’properties is still challenging and thoughtprovoking owing to their complex structure.Here,an underlying pyrrolic-N concentration and position effect on the pyrrolic-N-rich CDs’absorption was comprehensively elucidated based on the integrated experimental and computational studies.The assynthesized pyrrolic-N-rich CDs exhibit a first NIR window absorption centered at 650 nm with high photothermal conversion.Pyrrolic-N concentrations from 1.4%to 11.3%and positions(edge and mid-site)were systematically investigated.A mid-site pyrrolic-N was subsequently generated after the pyrrolic-N concentration more than 10%.Edge-site pyrrolic-N induces a frontier orbital hybridization,reducing bandgap energy,while mid-site pyrrolic-N plays a critical role in inducing a first NIR window absorption owing to their high charge transfer.Also,pyrrolic-N-rich CDs inherit a bowl-like topological feature,elevating the CDs’layer thickness as much as 0.71 nm.This study shed light on the design and optimization of pyrrolic-N on CDs for the first NIR window responsive materials in any biomedical application.展开更多
Waste generation from food manufacturing facilities poses a serious hazard like environmental degradation, water pollution, and land pollution due to its high nutrient composition. Specifically, solid waste(powder) di...Waste generation from food manufacturing facilities poses a serious hazard like environmental degradation, water pollution, and land pollution due to its high nutrient composition. Specifically, solid waste(powder) disposal requires additional energy sources in terms of scientific treatment, structured collection, and disposal packaging according to the safety regulation. Thus, this research discusses the viewpoint of integrating food processing waste as an organic carbon source with BG-11 medium for Chlorella vulgaris(FSP-E) growth. The food processing waste powders investigated in this study were obtained from milk, and biscuit manufacturing facilities. The culture medium was modified by combining both BG-11 and food processing waste powders to identify the optimal algal growth and biochemical content.Compared to the microalgae grown in BG-11 alone(IBG), the combination of biscuit waste and IBG produced higher biomass concentration(44%), with increased lipid(11%), protein(20%), and carbohydrate(57%) contents. Chlorella vulgaris was able to uptake nutrients from the culture medium with combination of food processing waste and IBG thus enhancing its growth. The results obtained also indicate that an integrated culture system using food processing waste and synthetic sources can generate energy out of waste by improving the bio-composition of the microalgae biomass.展开更多
Surface-enhanced Raman scattering(SERS)enables rapid detection of single molecules with high specificity.However,quantitative and sensitive SERS analysis has been a challenge due to the lack of reliable SERS-active ma...Surface-enhanced Raman scattering(SERS)enables rapid detection of single molecules with high specificity.However,quantitative and sensitive SERS analysis has been a challenge due to the lack of reliable SERS-active materials.In this study,we developed a quantitative SERS-based immunoassay using enzyme-guided Ag growth on Raman labeling compound(RLC)-immobilized gold nanoparticle(Au NP)-assembled silica NPs(SiO2@Au-RLC@Ag).The enzyme amplified Ag+reduction as well as Ag growth on the RLC-immobilized Au NP-assembled silica NPs(SiO2@Au-RLC),which resulted in a significant increase in SERS signal.In the presence of target antigens such as immunoglobulinG(IgG)or prostate-specific antigen(PSA),Ab1-Antigen-Ab2 immune complex with alkaline phosphatase triggered an enzyme-catalyzed reaction to convert 2-phospho-L-ascorbic acid(2-phospho-L-AA)to ascorbic acid(AA).As produced AA reduced Ag+to Ag,forming an Ag hot spot on the surface of SiO2@Au-RLC,which enhanced the SERS signal of SiO2@Au-RLC@Ag in a solution with a target antigen concentration.The plasmonic immunoassay for IgG detection showed a high linearity of SERS intensity in the range of 0.6 to 9.0 ng/mL with a detection limit(LOD)of 0.09 ng/mL,while an LOD of 0.006 ng/mL was obtained for PSA.The results indicate that the sensitivity of our novel SERS-based immunoassay is higher than that of conventional enzyme-based colorimetric immunoassays.展开更多
High efficiency and flexible inverted organic solar cells have been fabricated using solution-processed silver nanowire/zinc oxide composite transparent electrodes. The transparent electrodes showed a low sheet resist...High efficiency and flexible inverted organic solar cells have been fabricated using solution-processed silver nanowire/zinc oxide composite transparent electrodes. The transparent electrodes showed a low sheet resistance of -13 ff）.sq-1 and high transmittance of -93% as well as superior mechanical flexibility. Power conversion efficiencies of -7.57% and -7.21% were achieved for devices fabricated on glass and plastic substrate, respectively. Moreover, the flexible devices did not show any degradation in their performance even after being folded with a radius of-480 μm.展开更多
Erratum to Nano Research 2020,13(12):3338-3346 htts://doi.org/00.1007/s12274-020-3014-3 One author name and corresponding affiliation of the original version of this article were unfortunately mislabeled.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grant Nos.2018R1A6A1A03024334,2019R1A2C1007637,2021M3I3A1082880,2021R1I1A1A01044174)the Basic Science Research Capacity Enhancement Project through Korea Basic Science Institute (Grant No.2019R1A6C1010024)。
文摘The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.
文摘Objective:Acorus calamus(AC)L.(Araceae)is an annual semi-aquatic and aromatic plant found in Europe,North America and Asia.Its rhizomes are often used by Native Americans,Americans,and Chinese as well as by other cultures.Ethnobotanical studies and documents have shown their use in various disease treatments,such as insomnia,mental disorders,diabetes mellitus,epilepsy,inflammation,asthma,neuropathic pain,and diarrhea.In this study,the antidepressant activity of methanolic and hydroalcoholic extracts of the AC rhizome part in mice was investigated.Methods:Three doses of methanolic extract of AC rhizome(MEACR)(25,50 and 100 mg/kg b.wt),three doses of hydroalcoholic extract of AC rhizome(HAACR)(100,200 and 400 mg/kg b.wt),and standards(imipramine,15 mg/kg b.wt and fluoxetine,20 mg/kg b.wt)was daily oral administration to the mice for consecutive 14 days.The extract effect on the immobility time was monitored by a tail suspension test(TST)and a forced swimming test(FST).Monoamine oxidase(MAO)levels were also analyzed using standard methods.Results:The optimum antidepressant activity was viewed at 100 mg/kg b.wt of MEACR extract and400 mg/kg b.wt of HAACR extract with 23.82%and 20.59%immobility period reduction,respectively.Besides,the extracts weakened the FST-induced elevation of MAO activity significantly and returned to near-normal levels of neurotransmitters in the brain.100 mg/kg b.wt or above of MEACR extract significantly prevented the MAO-A and MAO-B activities in mice brain at a dose-dependent fashion.But,just 400 mg/kg b.wt of HAACR extract prevented the activity of MAO-A and MAO-B.Fluoxetine and imipramine showed a tendency to prevent the activity of MAO-A and MAO-B.Conclusion:This study suggests that AC rhizome extract mediated antidepressant activity by modulating the central neurochemical and hypothalamic-pituitary-adrenal(HPA)axis in response to FST and TSTinduced stress.Therefore,AC rhizome extract can be used as a valuable plant supplement to treat depressive disorders.
文摘This study investigated <i>Bacillus subtilis</i> ATCC13952 as an adsorbent for arsenic in groundwater. Batch experiments were used to determine the effect of contact time, adsorbent dose, arsenic (III) concentration, pH, and temperature on the process. The percentage of arsenic (III) removed was high at a contact time of four days, 3.0 mL of <i>Bacillus subtilis</i> ATCC13952, pH 8 and temperature of 35°C. The kinetics of the process showed the Elovich kinetics model as the best fit for the process. This indicates that arsenic removal was by chemisorption. The analysis of the nonlinear equilibrium isotherms and the error functions showed the Langmuir isotherm as best fit for the process. Mechanistic study of the process indicated bulk diffusion to be the rate-determining step. Thermodynamically, the process was favourable, spontaneous and feasible. When the community water samples were treated with the <i>Bacillus subtilis</i> ATCC13952 at the optimum contact time, adsorbent dose, pH and temperature, 99.96% - 99.97% of arsenic was removed across all sampling points within the studied communities. Hence, the results show that <i>Bacillus subtilis</i> ATCC13952 is an efficient adsorbent for arsenic in aqueous systems and the organism appears to hold the key to purging the environment of arsenic contamination.
文摘Au/n-Si （MS） structures with a high dielectric interlayer （0.03 graphene-doped PVA） are fabricated to investigate the illumination and voltage effects on electrical and dielectric properties by using capacitance-voltage （C-V） and conductance-voltage （G/w-V） measurements at room temperature and at 1 MHz. Some of the main electrical parameters such as concentration of doping atoms （ND）, barrier height （ ФB（ C - V） ）, depletion layer width （WD） and series resistance （Rs） show fairly large illumination dispersion. The voltage-dependent profile of surface states （Nss） and resistance of the structure （Ri ） are also obtained by using the dark-illumination capacitance （Cdark- Cm） and Nicollian-Brews methods, respectively, For a clear observation of changes in electrical parameters with illumination, the values of ND, WD, ФB（O- V） and Rs are drawn as a function of illumination intensity. The values of ND and WD change almost linearly with illumination intensity. On the other hand, Rs decreases almost exponentially with increasing illumination intensity whereas ФB（C - V） increases. The experimental results suggest that the use of a high dielectric interlayer （0.03 graphene-doped PVA） considerably passivates or reduces the magnitude of the surface states. The large change or dispersion in main electrical parameters can be attributed to generation of electron-hole pairs in the junction under illumination and to a good light absorption. All of these experimental results confirm that the fabricated Au/0.03 graphene-doped PVA/n-Si structure can be used as a photodiode or a capacitor in optoelectronic applications.
文摘The purpose of this research was to fmd out effectiveness of chloride solid membrane electrode of coated wire system compared to solid membrane electrode of composite system, the Nernstian response and character＇s potential response （detection limit, selectivity and response time）. The chloride ISEs （ion selective electrodes） in this research were the solid membrane chloride ISEs based AgC1. There were two types of chloride ISEs that were developed, namely the chloride ISEs of coated wire and composite systems. Both types of electrodes were characterized. The selectivity was done by comparing Esel of the chloride standard solutions and Esel of the interference ions （Br- and I-）. The measurement of chloride ions in water samples was done by using the coated wire chloride ISE, the composite chloride ISE and the Mohr method. We compared the result of the two chloride ISE methods to that of standard method for chloride determination （Mohr） by using F-test and Post Hoc Test LSD （least significant difference） and Duncan. Analysis by using F-test and Post Hoc Test （LSD and Duncan） and characterization results of both the methods showed that coated wire chloride ISE was more effective compared to composite chloride ISE. Nemstian response was 59.83 mV/decade, linier range measurement was 10-1-10-5 M, limit detection was 1.23 × 10-5 M, response time along was 25 s and interfering ion was 10-4 M Br-.
文摘Chemical tests were carried out on the aqueous extracts of the air-dried powders of two tropical moss plants, Thidium gratum and Barbula indica using standard procedures, to identify the phytochemical constituents. The extracts were screened for the presence and quantities of alkaloids, flavonoids, phenols, saponins and steroids with a view to assess their therapeutic values in ethnomedicine. The results of the phytochemical screening revealed the presence of alkaloids, flavonoids, phenols, saponins and steroids in varying quantities in the two moss plants but there was absence of phenol in Barbula indica. These results suggest that the two moss plants can be veritable and potential source of useful drugs in treatment of ailments.
文摘This study aims to investigate the antibacterial activities of essential oils isolated from various parts (buds, leaves and stems) of Eugenia caryophylata. The essentials oils were distillated by steam distillation, and the isolated was analyzed by GC and GC-MS. Five components of each sample of oils (buds, leaves and stems) were identified. Main component in the bud are eugenol (75.30%), eugenyl acetate (20.93%) and β-caryophyllene (3.00%) and eugenol (82.97%), β-caryophyllene (12.84%) in leaf oil, while in stem oil eugenol (97.75%). The oils were tested for in vitro antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), the Gram-negative bacteria (Escherichia coli and Salmonella typhimurium). The essential oils of bud, leaf and stem oil show that antibacterial activity against Gram-positive and Gram-negative bacteria.
文摘Road runoffs were sampled from five highways and five urban roads located in the New Juaben Municipality during the late storm events in the month of November 2014 and the early storm events in January 2015. A variety of water quality parameters such as, pH, temperature, turbidity, electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), aqueous concentrations of Chloride (Cl<sup>-</sup>), Phosphate (), Nitrate () and Sulphate () ions as well as the total concentrations of some selected heavy metals (Fe, Cu, Zn, Pb, Cd, Ni and Cr) were analysed for both periods. Although the results for the studied parameters, particularly the heavy metals varied for both sampling periods, the general trend indicated an increase in accumulation from November 2014 to January 2015. This was attributed to vehicular deposition as well as other natural and anthropogenic depositions on the road surfaces during the antecedent dry weather period between the two sampling months. The highest increase in pollutant loadings was associated with the heavy metals and some physico-chemical parameters such as TSS, TDS, EC and turbidity. Generally, EC, TDS, TSS and turbidity were above the permissible limits of the Environmental Protection Agency (EPA) of Ghana for both sampling periods. However, almost all the mean concentrations of heavy metals recorded for both road runoffs and the control samples were within the permissible limits of the Ghana EPA with some few exceptions.
基金financially supported by the National Natural Science Foundation of China(No.22150410327)the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT&Future Planning(No.2020R1A2C1102741).
文摘Prostate cancer(PC)biomarker-citrate detection is clinically important to diagnose PC in early stages.Methylquinolinium iodide(Q)conjugated indole-phenylboronic acid(IB)was designed as a red-emissive QIB probe for the detection of citrate through Lewis acid-base reaction and intramolecular charge transfer(ICT)sensing mechanisms.Boronic acid acts as Lewis acid as well as citrate(Lewis base)recognition unit.The probe reacted with citrate,showing enhanced red emissions.Since the probe has excellent water solubility and great biocompatibility,practical application in biological systems is possible.Citrate was monitored precisely in the mitochondria organelle(in vitro)of living cells with a positive charge on QIB.Also,endogenous(in situ)citrate was detected quantitatively to discriminate non-cancerous and PC mice,observed strong and lower(negligible)emission intensity on non-cancerous and cancerous prostate tissues,respectively.Because,the concentration of citrate is higher in healthy prostate compared with PC prostate.Furthermore,the analysis of sliced prostate tissues can give PC-related information for clinical diagnosis to prevent and treat PC in the initial stages.Therefore,we believe that the present probe is a promising biochemical reagent in diagnosing PC.
基金supported by the National Research Foundation of Korea(NRF),funded by the Ministry of Education,Science,and Technology(2018R1A6A1A03024334,NRF-2019R1A2C1006360)supported by Basic Science Research Capacity Enhancement Project through Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Education(2019R1A6C1010024)。
文摘Photoelectrochemical(PEC)water splitting is regarded as the most promising method to generate“green hydrogen”,and zinc oxide(ZnO)has been identified as one of the promising candidates for PEC water splitting owing to its straddling band alignment with the water redox level.However,its PEC performance is limited due to its wide bandgap and anticipated by photocorrosion in an aqueous medium.In this work,we present strategic improvements in the PEC water splitting performance of ZnO nanowires(NWs)by nitrogen(N)-doping along with photostability by the core–shell deposition of a NiOOH cocatalyst.Highly crystalline hierarchical ZnO NWs were fabricated on Si NWs(ZnO-Si HNWs)using a metal organic chemical vapor deposition approach.The NWs were then N-doped by annealing in an NH_(3) atmosphere.The N-doped ZnO-Si HNWs(N:ZnO-Si HNWs)showed enhanced visible light absorption,and suppressed recombination of the photogenerated carriers.As compared to ZnO-Si HNWs(0.045 m A cm^(-2) at 1.23 V vs RHE),the N:ZnO-Si HNWs(0.34 m A cm^(-2) at 1.23 V vs RHE)annealed in NH^(3) ambient for 3 h at 600℃showed 7.5-fold enhancement in the photocurrent density.NiOOH-deposited N:ZnO-Si HNW photoanodes with a photostability of 82.21%over 20000 s showed 10.69-fold higher photocurrent density(0.48 m A cm^(-2) at 1.23 V vs RHE)than ZnO-Si HNWs.
文摘Silver nanoparticles have provided considerable interest because of their potential applications in areas such as for fighting against all types of diseases, whether caused by germs, viruses, bacteria, allergens or pathogens. At the same time, silver nanoparticles have attracted considerable concern because of their potential applications in areas such as surface enhanced Raman scattering, nanoelectronics, optical filters, and electromagnetic interference shielding. [1, 2]
文摘Introduction: The mining industry ranks among the most hazardous occupations globally owing to the high prevalence of workplace accidents. To better protect workers in the industry, there is a need for a comprehensive understanding of risk factors, common illnesses and provision of PPE. Objective: This study examined the prevalence and underlying risk factors to work-related injuries, common illnesses, and Personal Protective Equipment (PPE) usage among mineworkers in two large-scale mining companies in Ghana that consented to participation. Methodology: Two hundred mineworkers were selected through stratified sampling in these companies using a semi-structured questionnaire. Chi-square test and binomial logistic regression were employed to determine the relationship between the incidence of occupational injury and selected risk factors using R studio. Results: The results showed that more than a tenth (16%;n = 31) of mineworkers had sustained physical injuries since being employed—mostly lacerations (53%). Out of those injured, (85%;n = 22) reportedly sustain an injury annually. A little more than half (57%;n = 112) of the mineworkers work for more than 40 hours per week. Injuries were significantly associated with the type of profession at the mine (p = 0.04;χ<sup>2</sup> = 4.3)—Technicians and Mechanics were more likely to be injured. Although not statistically significant, working for more than 40 hours/week doubled the odds of being injured at the workplace (aOR = 1.77;95% CI: -0.27 - 1.48). The topmost illnesses among mineworkers were musculoskeletal pains (MSPs) [53%] and headaches (35%). About two-thirds (65%) had all the needed PPEs for their work. Safety goggles were the predominant PPE reportedly lacking among the mineworkers (16%;n = 31). Conclusion: There is a need for targeted training/intervention programmes and adoption of assistive ergonomic devices to protect mineworkers.
基金This work was fully supported by the Indonesian Endowment Fund for Education and the Indonesian Science Fund through the International Collaboration RISPRO Funding Program(No.RISPRO/KI/B1/KOM/11/4542/2/2020).
文摘Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive range for biomedical application.However,a deep understanding of the role of the C-N configuration in the CDs’properties is still challenging and thoughtprovoking owing to their complex structure.Here,an underlying pyrrolic-N concentration and position effect on the pyrrolic-N-rich CDs’absorption was comprehensively elucidated based on the integrated experimental and computational studies.The assynthesized pyrrolic-N-rich CDs exhibit a first NIR window absorption centered at 650 nm with high photothermal conversion.Pyrrolic-N concentrations from 1.4%to 11.3%and positions(edge and mid-site)were systematically investigated.A mid-site pyrrolic-N was subsequently generated after the pyrrolic-N concentration more than 10%.Edge-site pyrrolic-N induces a frontier orbital hybridization,reducing bandgap energy,while mid-site pyrrolic-N plays a critical role in inducing a first NIR window absorption owing to their high charge transfer.Also,pyrrolic-N-rich CDs inherit a bowl-like topological feature,elevating the CDs’layer thickness as much as 0.71 nm.This study shed light on the design and optimization of pyrrolic-N on CDs for the first NIR window responsive materials in any biomedical application.
基金supported by the Fundamental Research Grant Scheme, Malaysia (No. FRGS/1/2019/STG05/UNIM/02/2)My PAIR-PHCHibiscus Grant (No. My PAIR/1/2020/STG05/UNIM/1)supported by the National Natural Science Foundation of China (No. 41876124)。
文摘Waste generation from food manufacturing facilities poses a serious hazard like environmental degradation, water pollution, and land pollution due to its high nutrient composition. Specifically, solid waste(powder) disposal requires additional energy sources in terms of scientific treatment, structured collection, and disposal packaging according to the safety regulation. Thus, this research discusses the viewpoint of integrating food processing waste as an organic carbon source with BG-11 medium for Chlorella vulgaris(FSP-E) growth. The food processing waste powders investigated in this study were obtained from milk, and biscuit manufacturing facilities. The culture medium was modified by combining both BG-11 and food processing waste powders to identify the optimal algal growth and biochemical content.Compared to the microalgae grown in BG-11 alone(IBG), the combination of biscuit waste and IBG produced higher biomass concentration(44%), with increased lipid(11%), protein(20%), and carbohydrate(57%) contents. Chlorella vulgaris was able to uptake nutrients from the culture medium with combination of food processing waste and IBG thus enhancing its growth. The results obtained also indicate that an integrated culture system using food processing waste and synthetic sources can generate energy out of waste by improving the bio-composition of the microalgae biomass.
基金This research was supported by the KU Research Professor Program of Konkuk University&funded by the Korean Health Technology R&D Project,Ministry of Health&Welfare(No.HI17C1264)Ministry of Science and ICT(No.NRF-2019R1G1A1006488).
文摘Surface-enhanced Raman scattering(SERS)enables rapid detection of single molecules with high specificity.However,quantitative and sensitive SERS analysis has been a challenge due to the lack of reliable SERS-active materials.In this study,we developed a quantitative SERS-based immunoassay using enzyme-guided Ag growth on Raman labeling compound(RLC)-immobilized gold nanoparticle(Au NP)-assembled silica NPs(SiO2@Au-RLC@Ag).The enzyme amplified Ag+reduction as well as Ag growth on the RLC-immobilized Au NP-assembled silica NPs(SiO2@Au-RLC),which resulted in a significant increase in SERS signal.In the presence of target antigens such as immunoglobulinG(IgG)or prostate-specific antigen(PSA),Ab1-Antigen-Ab2 immune complex with alkaline phosphatase triggered an enzyme-catalyzed reaction to convert 2-phospho-L-ascorbic acid(2-phospho-L-AA)to ascorbic acid(AA).As produced AA reduced Ag+to Ag,forming an Ag hot spot on the surface of SiO2@Au-RLC,which enhanced the SERS signal of SiO2@Au-RLC@Ag in a solution with a target antigen concentration.The plasmonic immunoassay for IgG detection showed a high linearity of SERS intensity in the range of 0.6 to 9.0 ng/mL with a detection limit(LOD)of 0.09 ng/mL,while an LOD of 0.006 ng/mL was obtained for PSA.The results indicate that the sensitivity of our novel SERS-based immunoassay is higher than that of conventional enzyme-based colorimetric immunoassays.
文摘High efficiency and flexible inverted organic solar cells have been fabricated using solution-processed silver nanowire/zinc oxide composite transparent electrodes. The transparent electrodes showed a low sheet resistance of -13 ff）.sq-1 and high transmittance of -93% as well as superior mechanical flexibility. Power conversion efficiencies of -7.57% and -7.21% were achieved for devices fabricated on glass and plastic substrate, respectively. Moreover, the flexible devices did not show any degradation in their performance even after being folded with a radius of-480 μm.
文摘Erratum to Nano Research 2020,13(12):3338-3346 htts://doi.org/00.1007/s12274-020-3014-3 One author name and corresponding affiliation of the original version of this article were unfortunately mislabeled.
