An AuNPs/Mesoporous NiO/Nickel Foam Nanocomposite as a Miniaturized Electrode for Heavy Metal Detection in Groundwater

Heavy metals,notably Pb2+and Cu^(2+),are some of the most persistent contaminants found in groundwater.Frequent monitoring of these metals,which relies on efficient,sensitive,cost-effective,and reliable methods,is a necessity.We present a nanocomposite-based miniaturized electrode for the concurrent measurement of Pb2+and Cu^(2+)by exploiting the electroanalytical technique of square wave voltammetry.We also propose a facile in situ hydrothermal calcination method to directly grow binder-free mesoporous Ni O on a three-dimensional nickel foam,which is then electrochemically seeded with gold nanoparticles(Au NPs).The meticulous design of a low-barrier Ohmic contact between mesoporous Ni O and Au NPs facilitates target-mediated nanochannel-confined electron transfer within mesoporous Ni O.As a result,the heavy metals Pb2+(0.020 mg.L^(-1)detection limit;2.0–16.0 mg.L^(-1)detection range)and Cu^(2+)(0.013 mg.L^(-1)detection limit;0.4–12.8 mg.L^(-1)detection range)can be detected simultaneously with high precision.Furthermore,other heavy metal ions and common interfering ions found in groundwater showed negligible impacts on the electrode’s performance,and the recovery rate of groundwater samples varied between 96.3%±2.1%and 109.4%±0.6%.The compactness,flexible shape,low power consumption,and ability to remotely operate our electrode pave the way for onsite detection of heavy metals in groundwater,thereby demonstrating the potential to revolutionize the field of environmental monitoring.

Enhanced production of cytidine 5'-monophosphate using biocatalysis of di-enzymes immobilized on amino-functionalized sepharose

Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.

Active oxygen center in oxidative coupling of methane on La_(2)O_(3) catalyst

La_(2)O_(3) catalyzed oxidative coupling of methane(OCM) is a promising process that converts methane directly to valuable C_(2)(ethylene and ethane) products. Our online MS transient study results indicate that pristine surface without carbonate species demonstrates a higher selectivity to C_(2) products, and a lower light-off temperature as well. Further study is focused on carbonate-free La_(2)O_(3) catalyst surface for identification of active oxygen species associated with such products behavior. XPS reveals unique oxygen species with O 1 s binding energy of 531.5 e V correlated with OCM catalytic activity and carbonates removal. However, indicated thermal stability of this species is much higher than the surface peroxide or superoxide structures proposed by earlier computation models. Motivated by experimental results,DFT calculations reveal a new more stable peroxide structure, formed at the subsurface hexacoordinate lattice oxygen sites, with energy 2.18 e V lower than the previous models. The new model of subsurface peroxide provides a perspective for understanding of methyl radicals formation and C_(2) products selectivity in OCM over La_(2)O_(3) catalyst.

中山市东凤镇某社区肝吸虫感染与防治调果分析

目的了解中山市东凤镇某社区肝吸虫感染状况及治疗效果。方法采用改良加藤氏厚涂片镜检法对本地人群粪便标本查找蛔虫、钩虫、鞭虫、蛲虫和肝吸虫,并对结果进行统计分析。对阳性病人进行服药后效果追踪。结果检测276人份粪便标本,发现钩虫3例,鞭虫2例,肝吸虫145例,肝吸虫阳性率为52.54%(145/276),男性感染率62.33%高于女性感染率41.54%,感染人群主要集中在≥20岁,多以低文化水平和高文化水平两个极端分布为主,感染人群多为农民和工人为主。服药治疗后,虫卵转阴率为87.07%。结论该社区寄生虫感染以肝吸虫为主,并高于中山市和广东的平均水平,必须加大宣传和积极防治,降低肝吸虫病对当地人民群众健康的危害。

Attaching Importance to the Strategy of Mathematical Culture in College Mathematics Teaching

The modem times industrial technology and the mathematics mutual promotion, the new technological revolution origins from thecomputation technology improvement, the modem network world is closely linked with the mathematics, mathematics development promotedthe technology advancement, the technology advancement also to impetus basic mathematics development, the two promoted the human culturedevelopment together, has brought the modem culture and the civilized unprecedented prosperity, also widely was affecting the modem life andthe thought. This paper analyzed the idea of attaching the importance to the strategy of mathematical culture in the college mathematics teaching.The proposed method is of great importance of enhancing the further direction of the mathematical education paradigms.

Analysis of Mathematical Modeling Thought in College Mathematics Teaching

The mathematical analysis enters the higher mathematics as the mathematics specialized student from the general elementary mathematics the initiation curriculum, its content and middle school mathematics still exist relate very much, while it during the expansion knowledge as also has many transformations. Under this basis, this paper proposes the analysis of the mathematical modeling thought in college mathematics teaching. Mathematics modelling teaching uses the open style teaching method also to wait for consummates regards the concrete course content the main point, the function as carries on each kind of variant to the open style mathematics educational model enable this kind of pattern to have pointed. We propose the novel paradigm for the education that will then be essential for the further development of the systems, in the future, we will then apply more of the methodologies to enhance the current proposed model.

Protective Effect of Buyang Huanwu Decoction on Cerebral Ischemia/Reperfusion Injury by Inhibiting Autophagy Based on AMPK/UIK1Signaling Pathway

The aim of the paper is to explore whether AMPK/U1K1 signaling pathway is involved in regulating autophagy and alleviating cerebral ischemia/reperfusion(I/R)injury.On this basis,study the regulatory effect of Buyang Huanwu Decoction(BHD)on AMPK/U1K1 signaling pathway,aiming to clarify the molecular mechanism of BHD in alleviating cerebral I/R injury and the protective effect of BHD containing serum(BHDS)on OGD/R neurons.The research group adopted the following methods:Neurons cultured for 7 days in vitro were randomly divided into normal control group,model group(OGD/R),AMPK activator(AICAR)group(3 mmol/L),Buyang Huanwu Decoction medicated serum(BHDS)group(3%),Buyang Huanwu Decoction medicated serum+AMPK activator(BHDS+AICAR)group.The protein expressions of p-AMPK,AMPK,p-UlKl,U1K1,Beclin-1 and LC3B in neurons were detected by Western blot,the fluorescence intensity and apoptosis rate of neuron autophagosome CYTO-ID staining were detected by flow cytometry,the fluorescence intensity and morphological changes of neuron LC3B were detected by immunofluorescence double labeling method,the morphological changes of neurons were observed by inverted microscope,and the survival rate of neurons was detected by CCK-8 method.Neuron OGD/R model and the optimal concentration of BHDS.The neurons in the model group were subjected to hypoxia and glucose deprivation for 1 h,2 h,3 h,4 h and reoxygenation and glucose deprivation for 24 h.The survival rate of neurons and the release rate of 1DH to determine whether the model was successfully established.And the results show that BHDS group,the survival rate of OGD/R neurons was significantly increased,and the apoptosis rate was significantly decreased.Among them,3%BHDS intervention at the same time of hypoxia glucose deprivation for 3 h and reoxygenation glucose for 24 h was the best condition.In BHDS group,the levels of p-AMPK/AMPK,p-UlKl/UlKl,beclin-1,CYTO-ID and LC3B fluorescence intensity,and the transformation from LC3B-I to LC3B-II of OGD/R neurons were significantly decreased.So we can draw a conclusion that BHD can inhibit autophagy and alleviate cerebral I/R injury through AMPK/U1K1 signaling pathway.

Effect of allelochemicals sustained-release microspheres on the ingestion, incorporation, and digestion abilities of Daphnia magna Straus

Allelochemicals sustained-release microspheres(ACs-SMs)exhibited great inhibition effect on algae,however,few studies have focused on ACs-SMs toxicity on invertebrate.In this study,the effects of single high-concentration ACs(15 mg/L,SH-ACs),repeated lowconcentration ACs(3×5 mg/L,RL-ACs)and ACs-SMs containing 15 mg/L ACs exposure on the ingestion,incorporation,and digestion of Daphniamagna Straus(DS)were investigated by stable isotope 15N labeling method.Meanwhile,the diversity and abundance of microflora in DS guts were determined by 16S rRNA genes and cloning methods.The results showed that SH-ACs exposure caused 50%and 33.3%death rates for newborn and adult DS,while RL-ACs exposure caused 10%death rate for newborn DS and no obvious effect on the activity of adult DS.And ACs-SMs exposure did not diminish the motility of both newborn and adult DS,indicating the lower acute toxicity of ACs-SMs.Furthermore,SH-ACs inhibited the ingestion(-6.45%),incorporation(-47.1%)and digestion(-53.8%)abilities of DS and reduced the microbial abundance(-27.7%)in DS guts.Compared with SH-ACs,RL-ACs showed relatively low impact on the ingestion(-3.23%),incorporation(-5.89%)and digestion(-23.9%)abilities of DS.Interestingly,ACs-SMs enhanced the ingestion(+9.68%),incorporation(+52.9%)and digestion(+51.3%)abilities of DS and increased the microbial abundance(+10.7%)in DS guts.Overall ACs and ACs-SMs reduced the diversity of microflora in DS guts.In conclusion,ACs-SMs can release ACs sustainably and prolong the sustained release time,which not only effectively reduce the toxicity of ACs,but also had positive effects on DS.

强流重离子加速器,肩负探索未知世界新使命

重大科技基础设施是为探索未知世界、发现自然规律、实现技术变革提供极限研究手段的大型复杂科学研究系统,是突破科学前沿,解决经济社会发展和国家安全重大科技问题的物质技术基础.《国家重大科技基础设施建设中长期规划(2012-2030年)》明确提出,瞄准科技前沿研究和国家重大战略需求,根据重大科技基础设施发展的国际趋势和国内基础,总体部署16项重大科技基础设施建设项目.强流重离子加速器装置(high intensity heavy-ion accelerator facility,HIAF)作为核物理科学领域的重要部署被列为建设重点项目之一,并于2018年12月底在广东惠州正式启动建设.图1为HIAF装置效果图.

双元件可调节人工晶状体设计

目的:设计一种新的双元件可调节人工晶状体,并对其成像质量进行评估。方法:通过光学设计软件Zemax,建立新设计的双元件可调节人工晶状体和人眼模型,模拟仿真其在不同视距下(L=6 m、L=70 cm、L=40 cm以及L=25 cm)的成像结果,得到空间频率为100 cycles/mm时的调制传递函数(MTF)值。与Simonov等研究结果进行对比分析,同时分析仿真结果是否满足人工晶状体植入光学特性和测试标准。结果:通过光学设计软件模拟仿真新设计的双元件可调节人工晶状体眼模型,其结果显示无论α=0°还是α=5°,瞳孔大小为3 mm时,单色光(λ=0.546μm)空间频率100 cycles/mm对应的MTF值均大于0.43,满足人工晶状体植入光学特性和测试标准。在α=0°时,仿真结果相较于Simonov等研究结果有较大提升;在α=5°时,无明显提升。结论:本研究设计的双元件可调节人工晶状体仿真结果满足人工晶状体植入光学特性和测试标准要求,相较于Simonov的研究结果,其整体性能有所提升。

Nutrient concentration variations during Oenanthe javanica growth and decay in the ecological floating bed system

The ecological floating bed system is a natural alternative to technical methods of wastewater treatment and involves complex processes induced by plants or microorganisms in the wastewater. This study aimed to identify nutrient concentration variations during Oenanthe javanica （Blume） DC growth and decay in the ecological floating bed system. Results showed that the third-order polynomial equation was suitable to describe pollutant concentration changes, showing that the effect of O. javanica ecological floating bed system on polluted water could be divided into the purification phase and decay phase. During the purification phase, nutrient concentrations rapidly decreased because O. javanica influenced water microbial communities and water physical parameters （i.e., dissolved oxygen, pH, and temperature）, and had a direct uptake of nutrients. However, during the decay phase, nitrogen and phosphorus concentrations in the plant tissues decreased, and these lost nutrients ultimately transferred to water and led to water quality deterioration. Results also showed that the uptake and storage of O. javanica in nutrients were temporary and the plant served only as media of the nutrients removed from the water. Under these circumstances, harvesting was an appropriate intervention to improve the treatment efficiency of O. javanica ecological floating bed system.

Acute toxicity assessment of drinking water source with luminescent bacteria: Impact of environmental conditions and a case study in Luoma Lake, East China

Protecting the quality of lake watersheds by preventing and reducing their contamination is an effective approach to ensure the sustainability of the drinking water supply.In this study,acute toxicity assessment was conducted on the basis of acute bioluminescence inhibition assay using the marine bacterium Vibrio fischeri as the test organism and Luoma Lake drinking water source in East China as the research target.The suitable ranges of environmental factors,including pH value,organic matter,turbidity,hardness,and dissolved oxygen of water samples were evaluated for the toxicity testing of bioluminescent bacteria.The physicochemical characteristics of water samples at the selected 43 sites of Luoma Lake watershed were measured.Results showed that the variations in pH value(7.31-8.41),hardness(5-20°d)and dissolved oxygen(4.44-11.03 mg/L)of Luoma Lake and its main inflow and outflow rivers had negligible impacts on the acute toxicity testing of V.fischeri.The luminescence inhibition rates ranged from-11.21%to 10.80%at the 43 sites.Pearson's correlation analysis in the experiment revealed that temperature,pH value,hardness,and turbidity had no correlation with luminescence inhibition rate,whereas dissolved oxygen showed a weak statistically positive correlation with a Pearson correlation coefficient of 0.455(p<0.05).

Ultrasensitive detection of endocrine disruptors via superfine plasmonic spectral combs

The apparent increase in hormone-induced cancers and disorders of the reproductive tract has led to a growing demand for new technologies capable of detecting endocrine disruptors.However,a long-lasting challenge unaddressed is how to achieve ultrahigh sensitive,continuous,and in situ measurement with a portable device for infield and remote environmental monitoring.Here we demonstrate a simple-to-implement plasmonic optical fiber biosensing platform to achieve an improved light–matter interaction and advanced surface chemistry for ultrasensitive detection of endocrine disruptors.Our platform is based on a gold-coated highly tilted fiber Bragg grating that excites high-density narrow cladding mode spectral combs that overlap with the broad absorption of the surface plasmon for high accuracy interrogation,hence enabling the ultrasensitive monitoring of refractive index changes at the fiber surface.Through the use of estrogen receptors as the model,we design an estradiol–streptavidin conjugate with the assistance of molecular dynamics,converting the specific recognition of environmental estrogens(EEs)by estrogen receptor into surface-based affinity bioassay for protein.The ultrasensitive platform with conjugate-induced amplification biosensing approach enables the subsequent detection for EEs down to 1.5×10−3 ng ml−1 estradiol equivalent concentration level,which is one order lower than the defined maximal E2 level in drinking water set by the Japanese government.The capability to detect EEs down to nanogram per liter level is the lowest limit of detection for any estrogen receptor-based detection reported thus far.Its compact size,flexible shape,and remote operation capability open the way for detecting other endocrine disruptors with ultrahigh sensitivity and in various hard-toreach spaces,thereby having the potential to revolutionize environment and health monitoring.

Label-free colorimetric nanosensor with improved sensitivity for Pb^2+ in water by using a truncated 8-17 DNAzyme

Water pollution accidents, such as the Flint water crisis in the United States, caused by lead contamination have raised concern on the safety of drinking water distribution systems. Thus, the routine monitoring of lead in water is highly required and demands efficient, sensitive, cost-effective, and reliable lead detection methods. This study reports a label-free colorimetric nanosensor that uses unmodified gold nanoparticles (AuNPs) as indicators to enable rapid and ultra-sensitive detection of lead in environmental water. The 8-17 DNAzyme was truncated in this study to facilitate the detachment of single-stranded DNA fragments after substrate cleavage in the presence of Pb「. The detached fragments were adsorbed over AuNPs and protected against salt concentration-induced aggregation. Accordingly, high Pb^2+ would result in rapid color change from blue to pink. The established sensing principle achieved a sensitive limit of detection of 0.2×10^-9mol/L Pb^2+. with a linear working range of two orders of magnitude from 0.5×10^-9mol/L to 5×10^-9mol/L. The selectivity of the nanosensor was demonstrated by evaluating the interfering metal ions. The developed nanosensor can serve as a substitute for the rapid analysis and monitoring of trace lead levels under the drinking water distribution system and even other environmental water samples.

Pomelo Peel-Inspired 3D-Printed Porous Structure for Efficient Absorption of Compressive Strain Energy

The porous structure in pomelo peel is believed to be responsible for the protection of its fruit from damage during the free falling from a tree.The quantitative understanding of the relationship between the deformation behavior and the porous structure could pave the way for the design of porous structures for efficient energy absorption.Here,a universal feature of pore distribution in pomelo peels along the radial direction is extracted from three varieties of pomelos,which shows strong correlation to the deformation behavior of the peels under compression.Guided by the porous design found in pomelo peels,porous polyether-ether-ketone(PEEK)cube is additively manufactured and possesses the highest ability to absorb energy during compression as compared to the non-pomelo-inspired geometries,which is further confirmed by the finite element simulation.The nature-optimized porous structure revealed here could guide the design of lightweight and high-energy-dissipating materials/devices.

Expression of human FUS protein in Drosophila leads to progressive neurodegeneration

Mutations in the Fused in sarcoma/Translated in liposarcoma gene(FUS/TLS,FUS)have been identified among patients with amyotrophic lateral sclerosis(ALS).FUS protein aggregation is a major pathological hallmark of FUS proteinopathy,a group of neurodegenerative diseases characterized by FUS-immunoreactive inclusion bodies.We prepared transgenic Drosophila expressing either the wild type(Wt)or ALS-mutant human FUS protein(hFUS)using the UAS-Gal4 system.When expressing Wt,R524S or P525L mutant FUS in photoreceptors,mushroom bodies(MBs)or motor neurons(MNs),transgenic flies show age-dependent progressive neural damages,including axonal loss in MB neurons,morphological changes and functional impairment in MNs.The transgenic flies expressing the hFUS gene recapitulate key features of FUS proteinopathy,representing the first stable animal model for this group of devastating diseases.

Rational synthetic combination genetic devices boosting high temperature ethanol fermentation

The growth and production of yeast in the industrial fermentation are seriously restrained by heat stress and exacerbated by heat induced oxidative stress.In this study,a novel synthetic biology approach was developed to globally boost the viability and production ability of S.cerevisiae at high temperature through rationally designing and combing heat shock protein(HSP)and superoxide dismutase(SOD)genetic devices to ultimately synergistically alleviate both heat stress and oxidative stress.HSP and SOD from extremophiles were constructed to be different genetic devices and they were preliminary screened by heat resistant experiments and anti-oxidative experiments,respectively.Then in order to customize and further improve thermotolerance of S.cerevisiae,the HSP genetic device and SOD genetic device were rationally combined.The results show the simply assemble of the same function genetic devices to solve heat stress or oxidative stress could not enhance the thermotolerance considerably.Only S.cerevisiae with the combination genetic device(FBA1p-sod-MB4-FBA1p-shsp-HB8)solving both stress showed 250%better thermotolerance than the control and displayed further 55%enhanced cell density compared with the strains with single FBA1p-sod-MB4 or FBA1p-shsp-HB8 at 42
C.Then the most excellent combination genetic device was introduced into lab S.cerevisiae and industrial S.cerevisiae for ethanol fermentation.The ethanol yields of the two strains were increased by 20.6%and 26.3%compared with the control under high temperature,respectively.These results indicate synergistically defensing both heat stress and oxidative stress is absolutely necessary to enhance the thermotolerance and production of S.cerevisiae.

Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant

Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant （WWTP） is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. Through analyzing a plug flow aeration tank in the Lucun WWTP, in Wuxi, China, the oxygenation capacity of fine-bubble aerators under process conditions have been measured in- situ using the off-gas method and the non-steady-state method. The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP had significantly different oxygen transfer performance; furthermore, the aerators in the same corridor shared almost equal oxygen transfer performance over the course of a day. Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water. The loss of oxygen transfer coefficient was over 50% under low-aeration conditions （aeration amount 〈 0.67 Nm 3 /hr）. However, as the aeration amount reached 0.96 Nm 3 /hr, the discrepancy of oxygen transfer between the process condition and clean water was negligible. The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

Inference and prediction of malaria transmission dynamics using time series data

Background:Disease surveillance systems are essential for effective disease intervention and control by monitoring disease prevalence as time series.To evaluate the severity of an epidemic,statistical methods are widely used to forecast the trend,seasonality,and the possible number of infections of a disease.However,most statistical methods are limited in revealing the underlying dynamics of disease transmission,which may be affected by various impact factors,such as environmental,meteorological,and physiological factors.In this study,we focus on investigating malaria transmission dynamics based on time series data.Methods:A data-driven nonlinear stochastic model is proposed to infer and predict the dynamics of malaria transmission based on the time series of prevalence data.Specifically,the dynamics of malaria transmission is modeled based on the notion of vectorial capacity(VCAP)and entomological inoculation rate(EIR).A particle Markov chain Monte Carlo(PMCMC)method is employed to estimate the model parameters.Accordingly,a one-step-ahead prediction method is proposed to project the number of future malaria infections.Finally,two case studies are carried out on the inference and prediction of Plasmodium vivax transmission in Tengchong and Longling,Yunnan province,China.Results:The results show that the trained data-driven stochastic model can well fit the historical time series of P.vivax prevalence data in both counties from 2007 to 2010.Moreover,with well-trained model parameters,the proposed one-step-ahead prediction method can achieve better performances than that of the seasonal autoregressive integrated moving average model with respect to predicting the number of future malaria infections.Conclusions:By involving dynamically changing impact factors,the proposed data-driven model together with the PMCMC method can successfully(i)depict the dynamics of malaria transmission,and(ii)achieve accurate one-step-ahead prediction about malaria infections.Such a data-driven method has the potential to investigate malaria transmission dynamics in other malaria-endemic countries/regions.