Acetyltransferases,required to transfer an acetyl group on protein are highly conserved proteins that play a crucial role in development and disease.Protein acetylation is a common post-translational modification pivo...Acetyltransferases,required to transfer an acetyl group on protein are highly conserved proteins that play a crucial role in development and disease.Protein acetylation is a common post-translational modification pivotal to basic cellular processes.Close to 80%-90%of proteins are acetylated during translation,which is an irreversible process that affects protein structure,function,life,and localization.In this review,we have discussed the various N-acetyltransferases present in humans,their function,and how they might play a role in diseases.Furthermore,we have focused on N-acetyltransferase 9 and its role in microtubule stability.We have shed light on how N-acetyltransferase 9 and acetylation of proteins can potentially play a role in neurodegenerative diseases.We have specifically discussed the N-acetyltransferase 9-acetylation independent function and regulation of c-Jun N-terminal kinase signaling and microtubule stability during development and neurodegeneration.展开更多
Alzheimer＇s disease（AD）, a fatal progressive neurodegenerative disorder, has no cure to date. One of the causes of AD is the accumulation of amyloid-beta 42（Aβ42） plaques, which result in the onset of neurodegen...Alzheimer＇s disease（AD）, a fatal progressive neurodegenerative disorder, has no cure to date. One of the causes of AD is the accumulation of amyloid-beta 42（Aβ42） plaques, which result in the onset of neurodegeneration. It is not known how these plaques trigger the onset of neurodegeneration. There are several animal models developed to（i） study etiology of disease,（ii） look for genetic modifiers, and（iii） identify chemical inhibitors that can block neurodegeneration and help to find cure for this disease. An insect model of Drosophila melanogaster has also provided new insights into the disease. Here we will discuss the utility of the Drosophila eye model to study Alzheimer＇s disease.展开更多
Alzheimer’s disease(hereafter AD) is a progressive neurodegenerative disorder that affects the central nervous system. There are multiple factors that cause AD, viz., accumulation of extracellular Amyloid-beta 42 pla...Alzheimer’s disease(hereafter AD) is a progressive neurodegenerative disorder that affects the central nervous system. There are multiple factors that cause AD, viz., accumulation of extracellular Amyloid-beta 42 plaques, intracellular hyper-phosphorylated Tau tangles, generation of reactive oxygen species due to mitochondrial dysfunction and genetic mutations. The plaques and tau tangles trigger aberrant signaling, which eventually cause cell death of the neurons. As a result, there is shrinkage of brain, cognitive defects, behavioral and psychological problems. To date, there is no direct cure for AD. Thus, scientists have been testing various strategies like screening for the small inhibitor molecule library or natural products that may block or prevent onset of AD. Historically, natural products have been used in many cultures for the treatment of various diseases. The research on natural products have gained importance as the active compounds extracted from them have medicinal values with reduced side effects, and they are bioavailable. The natural products may target the proteins or members of signaling pathways that get altered in specific diseases. Many natural products are being tested in various animal model systems for their role as a potential therapeutic target for AD, and to address questions about how these natural products can rescue AD or other neurodegenerative disorders. Some of these products are in clinical trials and results are promising because of their neuroprotective, anti-inflammatory, antioxidant, anti-amyloidogenic, anticholinesterase activities and easy availability. This review summarizes the use of animal model systems to identify natural products, which may serve as potential therapeutic targets for AD.展开更多
The Global Boundary Stratotype Section and Point （GSSP） for the Katian Stage of the Upper Ordovician Series is defined as the 4.0 m-level above the base of the Bigfork Chert in the Black Knob Ridge section, southeas...The Global Boundary Stratotype Section and Point （GSSP） for the Katian Stage of the Upper Ordovician Series is defined as the 4.0 m-level above the base of the Bigfork Chert in the Black Knob Ridge section, southeastern Oklahoma. This point in this section is coincident with the first appearance of the graptolite Diplacanthograptus caudatus, which has proved to be a reliable datum for precise worldwide correlation. The FAD ofD. caudatus occurs very near the first occurrences of the graptolites D. lanceolatus, Co.rynoides americanus, Orthograptus pageanus, O. quadrimucronatus, Dicranograptus hians, and Neurograptus margaritatus. This rapid succession of fossil species appearance events provides a secure basis for identification of the base of the Katian Stage of the Upper Ordovician Series and for its global chronostratigraphic correlation.展开更多
The controlling plastic deformation mechanisms(i.e.slip or twinning)and the structural crash performance of Mg alloys are strongly influenced by loading mode,texture and microstructure.This paper summarizes the main r...The controlling plastic deformation mechanisms(i.e.slip or twinning)and the structural crash performance of Mg alloys are strongly influenced by loading mode,texture and microstructure.This paper summarizes the main results from an experimental program to assess these effects for commercial Mg alloy extrusions(AM30 and AZ31),sheet(AZ31),and high pressure die castings(HPDC,AM50 and AM60).Uniaxial tensile and compressive tests were performed over a wide range of strain rate and temperature(i.e.0.00075–2800 s^(−1) and 100℃ to−150℃)using conventional servo-hydraulic and high-strain-rate universal test machines and a split-Hopkinson-bar(SHB)apparatus.In primarily-slip-dominant deformation,the true stress–strain curves showed approximate power-law behavior,and the effects of strain rate and temperature on yield strength could be approximately described by constitutive equations linearly dependent on the rate parameter,Tln(5.3×10^(7)/ɛ˙)where T is test temperature in Kelvin andɛ˙is strain rate in s^(−1).In primarily-twin-dominant deformation,the effects of strain rate and temperature on yield and initial flow stress were negligible or small from quasi-static to 2800 s^(−1) owing to the athermal characteristics of mechanical twinning;the effects may become more pronounced with exhaustion of twinning and increasing proportion of slip.展开更多
In this paper we report a new method to fabricate nanostructured films, La0.67Ca0.33MnO3 （LCMO） nanostructured films have been fabricated by using pulsed electron beam deposition （PED） on anodized aluminium oxide ...In this paper we report a new method to fabricate nanostructured films, La0.67Ca0.33MnO3 （LCMO） nanostructured films have been fabricated by using pulsed electron beam deposition （PED） on anodized aluminium oxide （AAO） membranes, The magnetic and electronic transport properties are investigated by using the Quantum Design physics properties measurement system （PPMS） and magnetic properties measurement system （MPMS）. The resistance peak temperature （Tp） is about 85 K and the Curie temperature （To） is about 250 K for the LCMO film on an AAO membrane with a pore diameter of 20nm. Large magnetoresistance ratio （MR） is observed near Tp. The MR is as high as 85% under 1 T magnetic field. The great enhancement of MR at low magnetic fields could be attributed to the lattice distortion and the grain boundary that are induced by the nanopores on the AAO membrane.展开更多
Cr-doped CdS nanowires were synthesized in large scale through thermal co-evaporation of CdS and metal Cr powders. General morphology, detailed microstructure and optical properties were characterized using various te...Cr-doped CdS nanowires were synthesized in large scale through thermal co-evaporation of CdS and metal Cr powders. General morphology, detailed microstructure and optical properties were characterized using various techniques. Devices consisting of individual Cr-doped CdS nanowire were fabricated and they exhibited remarkable rectifying characteristics. Ⅰ-Ⅴ curves of individual Cr-doped CdS nanowire devices demonstrate that the present nanowires are n-type doped and have high conductivity （10.96 Ω^-1cm^-1）, indicating great potential applications in nanoscale electronic and optoelectronic devices.展开更多
This study assessed the feasibility of utilizing activated carbon and clay minerals for treating water impacted with the bittering agent denatonium benzoate (DB). Our specific study objectives were to 1) evaluate dena...This study assessed the feasibility of utilizing activated carbon and clay minerals for treating water impacted with the bittering agent denatonium benzoate (DB). Our specific study objectives were to 1) evaluate denatonium ion sorption to smectite clay minerals (bentonite and hectorite) and activated carbon (powdered and granular) at constant pH and ionic strength and 2) examine the impact of pH on denatonium ion sorption to each solid material. The experimental results indicated that high doses (33,000 mg/L) of as-received granular activated carbon and as-received clay minerals completely removed denatonium from aqueous solutions containing 100 - 1000 mg/L denatonium benzoate. Powdered activated carbon at doses of 5 - 100 mg/L exhibited favorable monolayer sorption of denatonium ions from a pH 6.95, 70 mg/L aqueous denatonium benzoate solution with a Langmuir separation factor (r) of 0.481, a maximum sorption capacity (Sm) of 74 mg/g, and a Langmuir constant of 15.3 L/g. A maximum removal of 23% of denatonium was achieved at the highest powdered activated carbon dosage employed. Denatonium ion removal with peroxide treated bentonite and peroxide treated hectorite did not result in complete removal of the ion and exhibited favorable sorption as evidenced by Freundlich 1/n values ranging from 0.803 to 1.194;Freundlich constants (Kf) ranged from 8 ng/L to 575 ng/L. Denatonium ion sorption to peroxide treated bentonite appeared to depend on pH while hectorite sorption of denatonium ions was independent of hydrogen ion concentrations. For powdered activated carbon adsorption, as pH increased denatonium ion sorption decreased. Overall, the work demonstrates that denatonium can be effectively removed from water via activated carbon or clay mineral sorption.展开更多
The influence of the RE-rich phase distribution in the precursor alloys on the anisotropy of the hydrogenation disproportionation desorption recombination（HDDR） processed powders is investigated. The homogenized ing...The influence of the RE-rich phase distribution in the precursor alloys on the anisotropy of the hydrogenation disproportionation desorption recombination（HDDR） processed powders is investigated. The homogenized ingot alloy and the as-cast strip casting（SC） alloy with a uniform RE-rich grain boundary phase lead to high anisotropy of the refined powders,acquiring degrees of alignment（DOA） of 0.62 and 0.54, respectively. The RE-rich phase aggregation results in a deteriorated DOA of the powders due to the drastic disproportionation rate, while a thin and uniform RE-rich phase distribution is beneficial for DOA. A reaction model of the initial particle microstructure is proposed for optimizing the HDDR powder anisotropy.展开更多
This article reports the latest development of a wireless sensing system,named Martlet,on high-g shock acceleration measurement.The Martlet sensing node design is based on a Texas Instruments Piccolo microcontroller,w...This article reports the latest development of a wireless sensing system,named Martlet,on high-g shock acceleration measurement.The Martlet sensing node design is based on a Texas Instruments Piccolo microcontroller,with clock frequency programmable up to 90 MHz.The high clock frequency of the microcontroller enables Martlet to support high-frequency data acquisition and high-speed onboard computation.In addition,the extensible design of the Martlet node conveniently allows incorporation of multiple sensor boards.In this study,a high-g accelerometer interface board is developed to allow Martlet to work with the selected microelectromechanical system(MEMS)high-g accelerometers.Besides low-pass and highpass filters,amplification gains are also implemented on the high-g accelerometer interface board.Laboratory impact experiments are conducted to validate the performance of the Martlet wireless sensing system with the high-g accelerometer board.The results of this study show that the performance of the wireless sensing system is comparable to the cabled system.展开更多
Limited research has suggested iron oxide nanoparticles (FeNP) have an inhibitory effect against several different genera of bacteria: Staphylococcus, Bacillus and Pseudomonas spp. In this study we looked at the effec...Limited research has suggested iron oxide nanoparticles (FeNP) have an inhibitory effect against several different genera of bacteria: Staphylococcus, Bacillus and Pseudomonas spp. In this study we looked at the effect of three different sets of Fe3O4 nanoparticles (FeNPs) on the development of Pseudomonas aeruginosa PAO1 biofilms. Two of the tested NPs were SPIONs (Superparamagnetic Iron Oxide Nanoparticles). Exposure of cells to the SPIONs at concentrations up to 200 μg/ml resulted in an increase in biofilm biomass by 16 h under static conditions and a corresponding increase in cell density in the bulk liquid. In contrast, these biofilms had decreased levels of extracellular DNA (eDNA). Fe(II) levels in the supernatants of biofilms formed in the presence of FeNPs exceeded 100 μM compared with 20 μM in control media without cells. Spent cell supernatants had little effect on Fe(II) levels. Cells also had an effect on the aggregation behavior of these nanoparticles. SPIONs incubated with cells exhibited a decrease in the number and size of FeNP aggregates visible using light microscopy. SPIONs resuspended in fresh media or spent culture supernatants formed large aggregates visible in the light microscope upon exposure to a supermagnet;and could be pelleted magnetically in microtitre plate wells. In contrast, SPION FeNPs incubated with cells were unaffected by exposure to the supermagnet and could not be pelleted. The results of this study indicate a need to reconsider the effects of FeNPs on bacterial growth and biofilm formation and the effect the bacterial cells may have on the use and recovery of SPIONs.展开更多
Denatonium benzoate is an aversive agent proposed for use in certain anti-freeze formulations to reduce poisoning events of pets and humans. Unfortunately, the sorption properties of denatonium cations to soil and/or ...Denatonium benzoate is an aversive agent proposed for use in certain anti-freeze formulations to reduce poisoning events of pets and humans. Unfortunately, the sorption properties of denatonium cations to soil and/or soil components have not been investigated. In this paper, denatonium sorption to reference kaolinite clay under varied pH, ionic strength, and cation identity is described. The data clearly indicate that the nature of the background electrolyte cation modulates denatonium sorption with enhanced sorption occurring the presence of potassium ions versus minimal sorption occurring in a calcium chloride electrolyte at each pH studied as estimated using Dubinin-Raduskevich (D-R) isotherms. The effect of background electrolyte concentration on sorption was consistent with an ion-exchange process wherein the sorption capacity increased with decreased background electrolyte concentration. An interesting and unexpected observation of increased sorption capacity (estimated using the D-R model) with decreasing pH was observed in 10 mM CaCl2 in contrast to an observed and expected increase in denatonium sorption to kaolinite in the presence of either of 10 mM NaCl or 10 mM KCl. Estimates of the mean sorption energy using D-R isotherms ranging from 2.65 kJ/mol in 10 mM CaCl2 at pH 4 to 4.68 kJ/mol at pH 10 suggesting that the sorption process is not exclusively ion-exchange.展开更多
Edge plane pyrolytic graphite (EPG) electrodes coated with the Co(II)/Pt(II)2 analog of 5,15-bis-(4-pyridyl)-10,20-bis-(3-methoxy-4-hydroxyphenyl)porphyrin undergo an electrochemical-chemical-electrochemical (ECE) rea...Edge plane pyrolytic graphite (EPG) electrodes coated with the Co(II)/Pt(II)2 analog of 5,15-bis-(4-pyridyl)-10,20-bis-(3-methoxy-4-hydroxyphenyl)porphyrin undergo an electrochemical-chemical-electrochemical (ECE) reaction when anodically scanned in 1.0 M sulfuric acid. The new redox couple formed from this anodic conditioning of the coated electrode is dependent on the pH of the solution. Roughened EPG electrodes coated with the Co(II)/Pt(II)2 trimetallic porphyrin show a catalytic shift of 400 mV for the reduction of O2 when compared to the reduction of O2 at a bare EPG electrode. An additional catalytic shift of ca. 150 mV is observed for O2 reduction at an EPG electrode coated with the Co(II)/Pt(II)2 porphyrin which has been oxidized in 1.0 M sulfuric acid. In addition to the added electrocatalysis, a significant percentage of O2 reduced at the oxidized Co(II)/Pt(II)2 EPG electrode is converted to H2O as determined by rotating disk electrode measurements.展开更多
Propolis collected by stingless bees from various types of plants has been used as an antimicrobial agent in several previous studies. We assessed the effect of propolis produced by a stingless bee, Trigona apicalis, ...Propolis collected by stingless bees from various types of plants has been used as an antimicrobial agent in several previous studies. We assessed the effect of propolis produced by a stingless bee, Trigona apicalis, on Apis florea experimentally infected with Nosema ceranae, a parasite of honeybees. For parasite inoculation each Nosema free-bee was fed 2μL of 50% （w/v） sucrose solution containing N. ceranae spores at 40,000 spores/bee and 0 as a negative control （CO）. Treated bees were provided with 0%, 10%, 20% and 50% propolis （w/v） in water, defined as 0P, 10P, 20P and 50P, respectively. We assessed the effects of propolis 14 days post inoculation. All propolis-treated bees had significantly higher survival than untreated bees. However, survival of Nosema-inoculated bees was lower than that of control bees. Bees treated with the highest propolis concentration （50P） had the highest survival ratio. No control bees became infected over the course of the study. However, N. ceranae infection rates of bees treated with 0P, 10P, 20P and 50P were 75 ± 1.4%, 72 ± 5.6%, 69± 4.2% and 47± 1.4%, respectively. In addition, propolis-treated bees had hypopharyngeal gland protein content that was significantly higher than 0P and CO bees. Overall, propolis treatment significantly reduced N. ceranae infection rate and bee mortality and was associated with increased hypopharyngeal gland protein concentration.展开更多
The technical feasibility of monitoring DNA melting and cooling transitions using a microcantilever substrate has been demonstrated and these results were compared with those measured in solution by circular dichroism...The technical feasibility of monitoring DNA melting and cooling transitions using a microcantilever substrate has been demonstrated and these results were compared with those measured in solution by circular dichroism. DNA hairpins have been immobilized on the surface of gold-coated microcantilever surfaces and their DNA melting and cooling transitions were monitored by nanomechanical deflections. The hairpins comprised of a 16 base-pair GACA repeat motif stem duplex with a 29 nucleotide variable region. Microcantilever deflection profiles, measured by the microcantilever response as a function of temperature, were unique to different hairpins indicative of the molecules’ general stability and denaturation characteristics. The major melting and cooling transition temperatures for all three immobilized oligonucleotides were between 41。C - 52。C. The composition and flexibility of the DNA stem loops were shown to influence the thermal transitions.展开更多
The effect of the rotation of a very good conducting cylinder on the backscattered field will be investigated where the incident wave is considered as a plane wave in both polarizations （E-wave and H-wave）. Previous...The effect of the rotation of a very good conducting cylinder on the backscattered field will be investigated where the incident wave is considered as a plane wave in both polarizations （E-wave and H-wave）. Previous work has explained that rotation or vibration of the object may induce phase changes of the scattered signal. Modulation during rotation or vibration is referred to as micro-Doppler effect. Also, the effect of the rotation of a conducting cylinder was investigated by many researchers in the past using the Galilean transformation. These analyses conclude that the effect of rotation does not exist in the case of a perfectly conducting cylinder in both polarizations. In this work, the Franklin transformation is used instead of the Galilean transformation to analyze scattering of both types of electromagnetic waves （H-wave and E-wave） by rotating a very good circular conducting cylinder. This work shows that the scattered field is affected by the rotation of a very good conducting cylinder, especially in the case of H-wave （TE-mode）. Finally, the model that will be presented is used to simulate rotation using static backscattered field data of an arbitrary object.展开更多
Infection caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV2)virus,responsible for the coronavirus disease 2019(COVID-19)pandemic,induces symptoms including increased inflammatory response,severe ...Infection caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV2)virus,responsible for the coronavirus disease 2019(COVID-19)pandemic,induces symptoms including increased inflammatory response,severe acute respiratory syndrome(SARS),cognitive dysfunction like brain fog,and cardiovascular defects.Long-term effects of SARS-CoV2 COVID-19 syndrome referred to as post-COVID-19 syndrome on age-related progressive neurodegenerative disorders such as Alzheimer's disease remain understudied.Using the targeted misexpression of individual SARS-CoV2 proteins in the retinal neurons of the Drosophila melanogaster eye,we found that misexpression of nonstructural protein 3(Nsp3),a papain-like protease,ablates the eye and generates dark necrotic spots.Targeted misexpression of Nsp3 in the eye triggers reactive oxygen species production and leads to apoptosis as shown by cell death reporters,terminal deoxynucleotidyl transferase(TdT)dUTP Nick-end labeling(TUNEL)assay,and dihydroethidium staining.Furthermore,Nsp3 misexpression activates both apoptosis and autophagy mechanism(s)to regulate tissue homeostasis.Transient expression of SARS-CoV2 Nsp3 in murine neuroblastoma,Neuro-2a cells,significantly reduced the metabolic activity of these cells and triggers cell death.Misexpression of SARS-CoV2 Nsp3 in an Alzheimer's disease transgenic fly eye model(glass multiple repeats[GMR]>amyloidβ42)further enhances the neurodegenerative rough eye phenotype due to increased cell death.These findings suggest that SARS-CoV2 utilizes Nsp3 protein to potentiate cell death response in a neurodegenerative disease background that has high pre-existing levels of neuroinflammation and cell death.展开更多
In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the ...In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the Analytic Hierarchy Process(AHP)in combination with Geographic Information Systems(GIS)to evaluate the potential groundwater zones in the Gombora watershed within the Omo Gibe basin in Ethiopia.Combining these two tools provided a detailed map showing potential groundwater areas.These zones are determined based on various thematic maps containing information about geology,soil texture,lineament density,slope,land use,and drainage density.The AHP method combines these data layers by assigning weights to each layer based on its importance for groundwater recharge.These weighted layers are then overlaid using a GIS platform to produce a conclusive map of potential groundwater areas.The groundwater potential within the watershed was qualitatively divided into five categories with area coverages of very good(1.6%),good(7.4%),moderate(21.4%),poor(51.6%),and very poor(17.9%)of thewatershed area.The accuracy of the groundwater potential zones was evaluated using the receiver operating characteristic(ROC)curve and the area under the curve(AUC),producing good results(AUC=75.5%).This research has shown that integrating AHP with GIS can effectively pinpoint potential groundwater zones.Additionally,the findings could play a key role in determining suitable locations for new groundwater wells and supplying valuable insights to decision-makers to aid in planning and implementing sustainable strategies for managing groundwater resources in the watershed.展开更多
基金supported by 1RO1EY032959-01 and RO1 supplement from NIH,Schuellein Chair Endowment Fund and STEM Catalyst Grant from the University of Dayton(to AS).
文摘Acetyltransferases,required to transfer an acetyl group on protein are highly conserved proteins that play a crucial role in development and disease.Protein acetylation is a common post-translational modification pivotal to basic cellular processes.Close to 80%-90%of proteins are acetylated during translation,which is an irreversible process that affects protein structure,function,life,and localization.In this review,we have discussed the various N-acetyltransferases present in humans,their function,and how they might play a role in diseases.Furthermore,we have focused on N-acetyltransferase 9 and its role in microtubule stability.We have shed light on how N-acetyltransferase 9 and acetylation of proteins can potentially play a role in neurodegenerative diseases.We have specifically discussed the N-acetyltransferase 9-acetylation independent function and regulation of c-Jun N-terminal kinase signaling and microtubule stability during development and neurodegeneration.
文摘Alzheimer＇s disease（AD）, a fatal progressive neurodegenerative disorder, has no cure to date. One of the causes of AD is the accumulation of amyloid-beta 42（Aβ42） plaques, which result in the onset of neurodegeneration. It is not known how these plaques trigger the onset of neurodegeneration. There are several animal models developed to（i） study etiology of disease,（ii） look for genetic modifiers, and（iii） identify chemical inhibitors that can block neurodegeneration and help to find cure for this disease. An insect model of Drosophila melanogaster has also provided new insights into the disease. Here we will discuss the utility of the Drosophila eye model to study Alzheimer＇s disease.
基金Schuellein Chair Endowment Fund to AS supports PD and Graduate program of Biology supports NGsupported by National Institute of General Medical Sciences(NIGMS)-1 R15 GM124654-01+2 种基金Schuellein Chair Endowment Fund(to AS)STEM Catalyst Grant from University of Daytonstart-up support from UD(to AS)
文摘Alzheimer’s disease(hereafter AD) is a progressive neurodegenerative disorder that affects the central nervous system. There are multiple factors that cause AD, viz., accumulation of extracellular Amyloid-beta 42 plaques, intracellular hyper-phosphorylated Tau tangles, generation of reactive oxygen species due to mitochondrial dysfunction and genetic mutations. The plaques and tau tangles trigger aberrant signaling, which eventually cause cell death of the neurons. As a result, there is shrinkage of brain, cognitive defects, behavioral and psychological problems. To date, there is no direct cure for AD. Thus, scientists have been testing various strategies like screening for the small inhibitor molecule library or natural products that may block or prevent onset of AD. Historically, natural products have been used in many cultures for the treatment of various diseases. The research on natural products have gained importance as the active compounds extracted from them have medicinal values with reduced side effects, and they are bioavailable. The natural products may target the proteins or members of signaling pathways that get altered in specific diseases. Many natural products are being tested in various animal model systems for their role as a potential therapeutic target for AD, and to address questions about how these natural products can rescue AD or other neurodegenerative disorders. Some of these products are in clinical trials and results are promising because of their neuroprotective, anti-inflammatory, antioxidant, anti-amyloidogenic, anticholinesterase activities and easy availability. This review summarizes the use of animal model systems to identify natural products, which may serve as potential therapeutic targets for AD.
基金Acknowledgments This work was supported by National Science Foundation grant EAR - 0106844 to D. Goldman and Estonian Science Foundation grant ETF - 5922 to J. Nōlvak. We would like to thank S.C. Finney for showing us the Black Knob Ridge section, suggesting its potential as a GSSP, and critically reviewing previous versions of the manuscript.
文摘The Global Boundary Stratotype Section and Point （GSSP） for the Katian Stage of the Upper Ordovician Series is defined as the 4.0 m-level above the base of the Bigfork Chert in the Black Knob Ridge section, southeastern Oklahoma. This point in this section is coincident with the first appearance of the graptolite Diplacanthograptus caudatus, which has proved to be a reliable datum for precise worldwide correlation. The FAD ofD. caudatus occurs very near the first occurrences of the graptolites D. lanceolatus, Co.rynoides americanus, Orthograptus pageanus, O. quadrimucronatus, Dicranograptus hians, and Neurograptus margaritatus. This rapid succession of fossil species appearance events provides a secure basis for identification of the base of the Katian Stage of the Upper Ordovician Series and for its global chronostratigraphic correlation.
基金This work is part of the crashworthiness R&D task of an on-going Canada-China-US Magnesium Front-End Research and Development(MFERD)project.The Canadian task is funded by the CCT&I and ASM-NGV programs,Govemment of Canada.
文摘The controlling plastic deformation mechanisms(i.e.slip or twinning)and the structural crash performance of Mg alloys are strongly influenced by loading mode,texture and microstructure.This paper summarizes the main results from an experimental program to assess these effects for commercial Mg alloy extrusions(AM30 and AZ31),sheet(AZ31),and high pressure die castings(HPDC,AM50 and AM60).Uniaxial tensile and compressive tests were performed over a wide range of strain rate and temperature(i.e.0.00075–2800 s^(−1) and 100℃ to−150℃)using conventional servo-hydraulic and high-strain-rate universal test machines and a split-Hopkinson-bar(SHB)apparatus.In primarily-slip-dominant deformation,the true stress–strain curves showed approximate power-law behavior,and the effects of strain rate and temperature on yield strength could be approximately described by constitutive equations linearly dependent on the rate parameter,Tln(5.3×10^(7)/ɛ˙)where T is test temperature in Kelvin andɛ˙is strain rate in s^(−1).In primarily-twin-dominant deformation,the effects of strain rate and temperature on yield and initial flow stress were negligible or small from quasi-static to 2800 s^(−1) owing to the athermal characteristics of mechanical twinning;the effects may become more pronounced with exhaustion of twinning and increasing proportion of slip.
基金Project supported by the key program of Natural Science Foundation of Zhejiang Provincial, China （Grant No Z605131）, National Natural Science Foundation of China （Grant No 60571029）, the ‘Hundred Talents Project＇ of Chinese Academy of Sciences, China, the Creative Research Group of the National Natural Science Foundation of China （Grant No 60321001）.
文摘In this paper we report a new method to fabricate nanostructured films, La0.67Ca0.33MnO3 （LCMO） nanostructured films have been fabricated by using pulsed electron beam deposition （PED） on anodized aluminium oxide （AAO） membranes, The magnetic and electronic transport properties are investigated by using the Quantum Design physics properties measurement system （PPMS） and magnetic properties measurement system （MPMS）. The resistance peak temperature （Tp） is about 85 K and the Curie temperature （To） is about 250 K for the LCMO film on an AAO membrane with a pore diameter of 20nm. Large magnetoresistance ratio （MR） is observed near Tp. The MR is as high as 85% under 1 T magnetic field. The great enhancement of MR at low magnetic fields could be attributed to the lattice distortion and the grain boundary that are induced by the nanopores on the AAO membrane.
基金Project supported by the key project of Zhejiang Provincial Natural Science Foundation （Grant No Z605131） and the National Natural Science Foundation of China （Grant No 60571029）. Tang Wei-Hua was supported by the 100-outstanding Talents Project of Chinese Academy of Sciences and the Creative Research Group of National Natural Science Foundation of China （Grant No 60321001）.
文摘Cr-doped CdS nanowires were synthesized in large scale through thermal co-evaporation of CdS and metal Cr powders. General morphology, detailed microstructure and optical properties were characterized using various techniques. Devices consisting of individual Cr-doped CdS nanowire were fabricated and they exhibited remarkable rectifying characteristics. Ⅰ-Ⅴ curves of individual Cr-doped CdS nanowire devices demonstrate that the present nanowires are n-type doped and have high conductivity （10.96 Ω^-1cm^-1）, indicating great potential applications in nanoscale electronic and optoelectronic devices.
文摘This study assessed the feasibility of utilizing activated carbon and clay minerals for treating water impacted with the bittering agent denatonium benzoate (DB). Our specific study objectives were to 1) evaluate denatonium ion sorption to smectite clay minerals (bentonite and hectorite) and activated carbon (powdered and granular) at constant pH and ionic strength and 2) examine the impact of pH on denatonium ion sorption to each solid material. The experimental results indicated that high doses (33,000 mg/L) of as-received granular activated carbon and as-received clay minerals completely removed denatonium from aqueous solutions containing 100 - 1000 mg/L denatonium benzoate. Powdered activated carbon at doses of 5 - 100 mg/L exhibited favorable monolayer sorption of denatonium ions from a pH 6.95, 70 mg/L aqueous denatonium benzoate solution with a Langmuir separation factor (r) of 0.481, a maximum sorption capacity (Sm) of 74 mg/g, and a Langmuir constant of 15.3 L/g. A maximum removal of 23% of denatonium was achieved at the highest powdered activated carbon dosage employed. Denatonium ion removal with peroxide treated bentonite and peroxide treated hectorite did not result in complete removal of the ion and exhibited favorable sorption as evidenced by Freundlich 1/n values ranging from 0.803 to 1.194;Freundlich constants (Kf) ranged from 8 ng/L to 575 ng/L. Denatonium ion sorption to peroxide treated bentonite appeared to depend on pH while hectorite sorption of denatonium ions was independent of hydrogen ion concentrations. For powdered activated carbon adsorption, as pH increased denatonium ion sorption decreased. Overall, the work demonstrates that denatonium can be effectively removed from water via activated carbon or clay mineral sorption.
基金Project supported by the National Natural Science Foundation of China(Grant No.51101167)the Ningbo Natural Science Foundation,China(Grant No.2013A610075)+4 种基金the Ningbo Science and Technology Project,China(Grant No.2013B10004)the Program of International Science and Technology Cooperation of China(Grant No.2010DFB53770)the China Postdoctoral Science Foundation(Grant No.2012M520943)the State Key Program of the National Natural Science Foundation of China(Grant No.2011AA03A401)the National Key Technologies R&D Program of China(Grant No.2012BAE01B03)
文摘The influence of the RE-rich phase distribution in the precursor alloys on the anisotropy of the hydrogenation disproportionation desorption recombination（HDDR） processed powders is investigated. The homogenized ingot alloy and the as-cast strip casting（SC） alloy with a uniform RE-rich grain boundary phase lead to high anisotropy of the refined powders,acquiring degrees of alignment（DOA） of 0.62 and 0.54, respectively. The RE-rich phase aggregation results in a deteriorated DOA of the powders due to the drastic disproportionation rate, while a thin and uniform RE-rich phase distribution is beneficial for DOA. A reaction model of the initial particle microstructure is proposed for optimizing the HDDR powder anisotropy.
文摘This article reports the latest development of a wireless sensing system,named Martlet,on high-g shock acceleration measurement.The Martlet sensing node design is based on a Texas Instruments Piccolo microcontroller,with clock frequency programmable up to 90 MHz.The high clock frequency of the microcontroller enables Martlet to support high-frequency data acquisition and high-speed onboard computation.In addition,the extensible design of the Martlet node conveniently allows incorporation of multiple sensor boards.In this study,a high-g accelerometer interface board is developed to allow Martlet to work with the selected microelectromechanical system(MEMS)high-g accelerometers.Besides low-pass and highpass filters,amplification gains are also implemented on the high-g accelerometer interface board.Laboratory impact experiments are conducted to validate the performance of the Martlet wireless sensing system with the high-g accelerometer board.The results of this study show that the performance of the wireless sensing system is comparable to the cabled system.
文摘Limited research has suggested iron oxide nanoparticles (FeNP) have an inhibitory effect against several different genera of bacteria: Staphylococcus, Bacillus and Pseudomonas spp. In this study we looked at the effect of three different sets of Fe3O4 nanoparticles (FeNPs) on the development of Pseudomonas aeruginosa PAO1 biofilms. Two of the tested NPs were SPIONs (Superparamagnetic Iron Oxide Nanoparticles). Exposure of cells to the SPIONs at concentrations up to 200 μg/ml resulted in an increase in biofilm biomass by 16 h under static conditions and a corresponding increase in cell density in the bulk liquid. In contrast, these biofilms had decreased levels of extracellular DNA (eDNA). Fe(II) levels in the supernatants of biofilms formed in the presence of FeNPs exceeded 100 μM compared with 20 μM in control media without cells. Spent cell supernatants had little effect on Fe(II) levels. Cells also had an effect on the aggregation behavior of these nanoparticles. SPIONs incubated with cells exhibited a decrease in the number and size of FeNP aggregates visible using light microscopy. SPIONs resuspended in fresh media or spent culture supernatants formed large aggregates visible in the light microscope upon exposure to a supermagnet;and could be pelleted magnetically in microtitre plate wells. In contrast, SPION FeNPs incubated with cells were unaffected by exposure to the supermagnet and could not be pelleted. The results of this study indicate a need to reconsider the effects of FeNPs on bacterial growth and biofilm formation and the effect the bacterial cells may have on the use and recovery of SPIONs.
文摘Denatonium benzoate is an aversive agent proposed for use in certain anti-freeze formulations to reduce poisoning events of pets and humans. Unfortunately, the sorption properties of denatonium cations to soil and/or soil components have not been investigated. In this paper, denatonium sorption to reference kaolinite clay under varied pH, ionic strength, and cation identity is described. The data clearly indicate that the nature of the background electrolyte cation modulates denatonium sorption with enhanced sorption occurring the presence of potassium ions versus minimal sorption occurring in a calcium chloride electrolyte at each pH studied as estimated using Dubinin-Raduskevich (D-R) isotherms. The effect of background electrolyte concentration on sorption was consistent with an ion-exchange process wherein the sorption capacity increased with decreased background electrolyte concentration. An interesting and unexpected observation of increased sorption capacity (estimated using the D-R model) with decreasing pH was observed in 10 mM CaCl2 in contrast to an observed and expected increase in denatonium sorption to kaolinite in the presence of either of 10 mM NaCl or 10 mM KCl. Estimates of the mean sorption energy using D-R isotherms ranging from 2.65 kJ/mol in 10 mM CaCl2 at pH 4 to 4.68 kJ/mol at pH 10 suggesting that the sorption process is not exclusively ion-exchange.
文摘Edge plane pyrolytic graphite (EPG) electrodes coated with the Co(II)/Pt(II)2 analog of 5,15-bis-(4-pyridyl)-10,20-bis-(3-methoxy-4-hydroxyphenyl)porphyrin undergo an electrochemical-chemical-electrochemical (ECE) reaction when anodically scanned in 1.0 M sulfuric acid. The new redox couple formed from this anodic conditioning of the coated electrode is dependent on the pH of the solution. Roughened EPG electrodes coated with the Co(II)/Pt(II)2 trimetallic porphyrin show a catalytic shift of 400 mV for the reduction of O2 when compared to the reduction of O2 at a bare EPG electrode. An additional catalytic shift of ca. 150 mV is observed for O2 reduction at an EPG electrode coated with the Co(II)/Pt(II)2 porphyrin which has been oxidized in 1.0 M sulfuric acid. In addition to the added electrocatalysis, a significant percentage of O2 reduced at the oxidized Co(II)/Pt(II)2 EPG electrode is converted to H2O as determined by rotating disk electrode measurements.
文摘Propolis collected by stingless bees from various types of plants has been used as an antimicrobial agent in several previous studies. We assessed the effect of propolis produced by a stingless bee, Trigona apicalis, on Apis florea experimentally infected with Nosema ceranae, a parasite of honeybees. For parasite inoculation each Nosema free-bee was fed 2μL of 50% （w/v） sucrose solution containing N. ceranae spores at 40,000 spores/bee and 0 as a negative control （CO）. Treated bees were provided with 0%, 10%, 20% and 50% propolis （w/v） in water, defined as 0P, 10P, 20P and 50P, respectively. We assessed the effects of propolis 14 days post inoculation. All propolis-treated bees had significantly higher survival than untreated bees. However, survival of Nosema-inoculated bees was lower than that of control bees. Bees treated with the highest propolis concentration （50P） had the highest survival ratio. No control bees became infected over the course of the study. However, N. ceranae infection rates of bees treated with 0P, 10P, 20P and 50P were 75 ± 1.4%, 72 ± 5.6%, 69± 4.2% and 47± 1.4%, respectively. In addition, propolis-treated bees had hypopharyngeal gland protein content that was significantly higher than 0P and CO bees. Overall, propolis treatment significantly reduced N. ceranae infection rate and bee mortality and was associated with increased hypopharyngeal gland protein concentration.
文摘The technical feasibility of monitoring DNA melting and cooling transitions using a microcantilever substrate has been demonstrated and these results were compared with those measured in solution by circular dichroism. DNA hairpins have been immobilized on the surface of gold-coated microcantilever surfaces and their DNA melting and cooling transitions were monitored by nanomechanical deflections. The hairpins comprised of a 16 base-pair GACA repeat motif stem duplex with a 29 nucleotide variable region. Microcantilever deflection profiles, measured by the microcantilever response as a function of temperature, were unique to different hairpins indicative of the molecules’ general stability and denaturation characteristics. The major melting and cooling transition temperatures for all three immobilized oligonucleotides were between 41。C - 52。C. The composition and flexibility of the DNA stem loops were shown to influence the thermal transitions.
文摘The effect of the rotation of a very good conducting cylinder on the backscattered field will be investigated where the incident wave is considered as a plane wave in both polarizations （E-wave and H-wave）. Previous work has explained that rotation or vibration of the object may induce phase changes of the scattered signal. Modulation during rotation or vibration is referred to as micro-Doppler effect. Also, the effect of the rotation of a conducting cylinder was investigated by many researchers in the past using the Galilean transformation. These analyses conclude that the effect of rotation does not exist in the case of a perfectly conducting cylinder in both polarizations. In this work, the Franklin transformation is used instead of the Galilean transformation to analyze scattering of both types of electromagnetic waves （H-wave and E-wave） by rotating a very good circular conducting cylinder. This work shows that the scattered field is affected by the rotation of a very good conducting cylinder, especially in the case of H-wave （TE-mode）. Finally, the model that will be presented is used to simulate rotation using static backscattered field data of an arbitrary object.
基金supported by 1RO1EY032959-01 from NIHSchuellein Chair Endowment FundSTEM Catalyst Grant from the University of Dayton(all to AS)。
文摘Infection caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV2)virus,responsible for the coronavirus disease 2019(COVID-19)pandemic,induces symptoms including increased inflammatory response,severe acute respiratory syndrome(SARS),cognitive dysfunction like brain fog,and cardiovascular defects.Long-term effects of SARS-CoV2 COVID-19 syndrome referred to as post-COVID-19 syndrome on age-related progressive neurodegenerative disorders such as Alzheimer's disease remain understudied.Using the targeted misexpression of individual SARS-CoV2 proteins in the retinal neurons of the Drosophila melanogaster eye,we found that misexpression of nonstructural protein 3(Nsp3),a papain-like protease,ablates the eye and generates dark necrotic spots.Targeted misexpression of Nsp3 in the eye triggers reactive oxygen species production and leads to apoptosis as shown by cell death reporters,terminal deoxynucleotidyl transferase(TdT)dUTP Nick-end labeling(TUNEL)assay,and dihydroethidium staining.Furthermore,Nsp3 misexpression activates both apoptosis and autophagy mechanism(s)to regulate tissue homeostasis.Transient expression of SARS-CoV2 Nsp3 in murine neuroblastoma,Neuro-2a cells,significantly reduced the metabolic activity of these cells and triggers cell death.Misexpression of SARS-CoV2 Nsp3 in an Alzheimer's disease transgenic fly eye model(glass multiple repeats[GMR]>amyloidβ42)further enhances the neurodegenerative rough eye phenotype due to increased cell death.These findings suggest that SARS-CoV2 utilizes Nsp3 protein to potentiate cell death response in a neurodegenerative disease background that has high pre-existing levels of neuroinflammation and cell death.
基金supported by the National Science Foundation-Hydrologic Science Program。
文摘In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the Analytic Hierarchy Process(AHP)in combination with Geographic Information Systems(GIS)to evaluate the potential groundwater zones in the Gombora watershed within the Omo Gibe basin in Ethiopia.Combining these two tools provided a detailed map showing potential groundwater areas.These zones are determined based on various thematic maps containing information about geology,soil texture,lineament density,slope,land use,and drainage density.The AHP method combines these data layers by assigning weights to each layer based on its importance for groundwater recharge.These weighted layers are then overlaid using a GIS platform to produce a conclusive map of potential groundwater areas.The groundwater potential within the watershed was qualitatively divided into five categories with area coverages of very good(1.6%),good(7.4%),moderate(21.4%),poor(51.6%),and very poor(17.9%)of thewatershed area.The accuracy of the groundwater potential zones was evaluated using the receiver operating characteristic(ROC)curve and the area under the curve(AUC),producing good results(AUC=75.5%).This research has shown that integrating AHP with GIS can effectively pinpoint potential groundwater zones.Additionally,the findings could play a key role in determining suitable locations for new groundwater wells and supplying valuable insights to decision-makers to aid in planning and implementing sustainable strategies for managing groundwater resources in the watershed.
