n-Hexadecane and pyrene biodegradation and metabolization by Rhodococcus sp. T1 isolated from oil contaminated soil

The high-molecular weight polycyclic aromatic hydrocarbons(PAHs) pyrene and typical long chain alkane nhexadecane are both difficult to degrade. In this study, n-hexadecane and pyrene degrading strain Rhodococcus sp. T1 was isolated from oil contaminated soil. Strain T1 could remove 90.81% n-hexadecane(2 vol%) and 42.79% pyrene(200 mg·L^(-1)) as a single carbon within 5 days, respectively. Comparatively, the degradation of pyrene increased to 60.63%, but the degradation of n-hexadecane decreased to 87.55% when these compounds were mixed. Additionally, identification and analysis of degradation metabolites of Rhodococcus sp. T1 in the above experiments showed that there were significant changes in alanine, methylamine, citric acid and heptadecanoic acid between sole and dual substrate degradation. The optimal conditions for degradation were then determined based on analysis of the pH, salinity, additional nutrient sources and liquid surface activity.Under the optimal conditions of pH 7.0, 35 °C, 0.5% NaCl, 5 mg·L^(-1) of yeast extract and 90 mg·L^(-1) of surfactant,the degradation increased in single or dual carbon sources. To our knowledge, this is the first study to discuss metabolite changes in Rhodococcus sp. T1 using sole substrate and dual substrate to enhance the long-chain alkanes and PAHs degradation potential.

Annual Variation of Water Quality in Aquaculture Ponds for Apostichopus japonicus

By measuring water temperature,salinity,pH,dissolved oxygen,nitrite and ammonia nitrogen,the annual variation regularity of water quality in the aquaculture ponds for sea cucumbers Apostichopus japonicus in Dalian were studied.Results showed that the physicochemical indicators kept changing in the year,and the various ranges of water temperature,salinity,pH,dissolved oxygen,nitrite,and ammonia nitrogen were 6.38-27.27℃,29.20‰-33.78‰,7.86-8.38,5.19-13.36 mg/L,0.0037-0.0090 mg/L and 0.0171-0.0908 mg/L,respectively.Analysis indicated that there was an extremely significant negative correlation between water temperature and dissolved oxygen(P<0.01),an extremely significant positive correlation between water temperature and ammonia nitrogen(P<0.01),a significant negative correlation between salinity and nitrite(P<0.05),a significant negative correlation between dissolved oxygen and nitrite(P<0.05),and an extremely significant negative correlation between dissolved oxygen and ammonia nitrogen(P<0.01)in the aquaculture ponds for sea cucumber in Dalian.Research showed that the water quality of aquaculture ponds kept fluctuating all the time during the tested period,there were complicated and close relationships among physicochemical indicators,and a slight variation of external factors would bring consecutive reactions to different indicators in the water quality of aquaculture ponds.A reference for the production and management of sea cucumbers could be provided from the results.

Effect of deformation of diamond anvil and sample in diamond anvil cell on the thermal conductivity measurement

Studies show that the sample thickness is an important parameter in investigating the thermal transport properties of materials under high-temperature and high-pressure(HTHP)in the diamond anvil cell(DAC)device.However,it is an enormous challenge to measure the sample thickness accurately in the DAC under severe working conditions.In conventional methods,the influence of diamond anvil deformation on the measuring accuracy is ignored.For a hightemperature anvil,the mechanical state of the diamond anvil becomes complex and is different from that under the static condition.At high temperature,the deformation of anvil and sample would be aggravated.In the present study,the finite volume method is applied to simulate the heat transfer mechanism of stable heating DAC through coupling three radiativeconductive heat transfer mechanisms in a high-pressure environment.When the temperature field of the main components is known in DAC,the thermal stress field can be analyzed numerically by the finite element method.The obtained results show that the deformation of anvil will lead to the obvious radial gradient distribution of the sample thickness.If the top and bottom surfaces of the sample are approximated to be flat,it will be fatal to the study of the heat transport properties of the material.Therefore,we study the temperature distribution and thermal conductivity of the sample in the DAC by thermal-solid coupling method under high pressure and stable heating condition.

Investigating the thermal conductivity of materials by analyzing the temperature distribution in diamond anvils cell under high pressure

Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and pressures.However,it is an enormous challenge to characterize the thermal and physical properties of materials using the diamond anvil cell(DAC)platform.In the present study,a steady-state method is used with a DAC and a combination of thermocouple temperature measurement and numerical analysis is performed to calculate the thermal conductivity of the material.To this end,temperature distributions in the DAC under high pressure are analyzed.We propose a three-dimensional radiative-conductive coupled heat transfer model to simulate the temperature field in the main components of the DAC and calculate in situ thermal conductivity under high-temperature and high-pressure conditions.The proposed model is based on the finite volume method.The obtained results show that heat radiation has a great impact on the temperature field of the DAC,so that ignoring the radiation effect leads to large errors in calculating the heat transport properties of materials.Furthermore,the feasibility of studying the thermal conductivity of different materials is discussed through a numerical model combined with locally measured temperature in the DAC.This article is expected to become a reference for accurate measurement of in situ thermal conductivity in DACs at high-temperature and high-pressure conditions.

Structural and functional imaging of brains

Analyzing the complex structures and functions of brain is the key issue to understanding the physiological and pathological processes.Although neuronal morphology and local distribution of neurons/blood vessels in the brain have been known,the subcellular structures of cells remain challenging,especially in the live brain.In addition,the complicated brain functions involve numerous functional molecules,but the concentrations,distributions and interactions of these molecules in the brain are still poorly understood.In this review,frontier techniques available for multiscale structure imaging from organelles to the whole brain are first overviewed,including magnetic resonance imaging(MRI),computed tomography(CT),positron emission tomography(PET),serial-section electron microscopy(ss EM),light microscopy(LM)and synchrotron-based X-ray microscopy(XRM).Specially,XRM for three-dimensional(3D)imaging of large-scale brain tissue with high resolution and fast imaging speed is highlighted.Additionally,the development of elegant methods for acquisition of brain functions from electrical/chemical signals in the brain is outlined.In particular,the new electrophysiology technologies for neural recordings at the single-neuron level and in the brain are also summarized.We also focus on the construction of electrochemical probes based on dual-recognition strategy and surface/interface chemistry for determination of chemical species in the brain with high selectivity and long-term stability,as well as electrochemophysiological microarray for simultaneously recording of electrochemical and electrophysiological signals in the brain.Moreover,the recent development of brain MRI probes with high contrast-to-noise ratio(CNR)and sensitivity based on hyperpolarized techniques and multi-nuclear chemistry is introduced.Furthermore,multiple optical probes and instruments,especially the optophysiological Raman probes and fiber Raman photometry,for imaging and biosensing in live brain are emphasized.Finally,a brief perspective on existing challenges and further research development is provided.

Nanostructured polyvinylpyrrolidone-curcumin conjugates allowed for kidney-targeted treatment of cisplatin induced acute kidney injury

Acute kidney injury(AKI)leads to unacceptably high mortality due to difficulties in timely intervention and less efficient renal delivery of therapeutic drugs.Here,a series of polyvinylpyrrolidone(PVP)-curcumin nanoparticles(PCurNP)are designed to meet the renal excretion threshold(~45 kDa),presenting a controllable delivery nanosystem for kidney targeting.Renal accumulation of the relatively small nanoparticles,^(89)Zr-PCurNP M10 with the diameter between 5 and 8 nm,is found to be 1.7 times and 1.8 times higher than the accumulation of^(89)Zr-PCurNP M29(20-50 nm)and M40(20-50 nm)as revealed by PET imaging.Furthermore,serum creatinine analysis,kidney tissues histology,and tubular injury scores revealed that PCurNP M10 efficiently treated cisplatin-induced AKI.Herein,PCurNP offers a novel and simple strategy for precise PET image-guided drug delivery of renal protective materials.

In situ stress state and seismic hazard in the Dayi seismic gap of the Longmenshan thrust belt

In the Longmenshan thrust belt,the Dayi seismic gap,an area with few earthquakes,is located between the ruptures of the 2008 Wenchuan Earthquake and the 2013 Lushan Earthquake,with a length of approximately 40–60 km.To date,however,the extent of the seismic hazard of the Dayi seismic gap and whether this gap is under high stress are still hotly debated.To further evaluate the seismic hazard of the Dayi seismic gap with regard to stress,two boreholes(1,000 and 500 m deep)were arranged to carry out hydraulic fracturing in situ stress measurement on either side of the Shuangshi-Dachuan fault zone.This zone has a high seismic hazard and the capacity to undergo surface rupture.Through the analogy of this new data with stability analysis using Byerlee’s Law and existing stress measurement data collected before strong earthquakes,the results show that the area surrounding the Shuangshi-Dachuan fault zone in the Dayi seismic gap(Dachuan Town)is in a state of high in situ stress,and has the conditions necessary for friction slip,with the potential hazard of moderate to strong earthquakes.Our results are the first to reveal the in situ stress profile at a depth of 1,000 m in the Dayi seismic gap,and provide new data for comprehensive evaluation of the seismic hazard in this seismic gap,which is of great significance to explore the mechanism of earthquake occurrence and to help mitigate future disaster.

Efficient renal clearance of DNA tetrahedron nanopartides enables quantitative evaluation of kidney function

DNA tetrahedro n nano structure (DTN) is one of the simplest DNA nano structures and has bee n successfully applied for biose nsin g, imagi ng, and treatment of can cer. To facilitate its biomedical applications and pote ntial clinical tran slation, fun dame ntal un derstandi ng of DTN's transportation among major organs in living organisms becomes increasingly important. Here, we describe the efficient renal clearanee of DTN in healthy mice by using positron emission tomography (PET) imaging. The kidney elimination of DTN was later applied for renal function evaluation in murine models of unilateral ureteral obstruction (UUO). We further established a mathematical program of DTN to validate its changes of transportation pattern in healthy and UUO mice. We believe the establishment of pharmacokinetic profiles and mathematical model of DTN may provide in sight for future optimization of DNA nano structures for biomedical applications.

Elevated atmospheric CO_(2) impact on carbon and nitrogen transformations and microbial community in replicated wetland

Background:Elevated atmospheric CO_(2) has direct and indirect influences on ecosystem processes.The impact of elevated atmospheric CO_(2) concentration on carbon and nitrogen transformations,together with the microbial community,was evaluated with water hyacinth(Eichhornia crassipes)in an open-top chamber replicated wetland.The responses of nitrogen and carbon pools in water and wetland soil,and microbial community abundance were studied under ambient CO_(2) and elevated CO_(2)(ambient+200μL L^(−1)).Results:Total biomass for the whole plant under elevated CO_(2) increased by an average of 8%(p=0.022).Wetlands,with water hyacinth,showed a significant increase in total carbon and total organic carbon in water by 7%(p=0.001)and 21%(p=0.001),respectively,under elevated CO_(2) compared to that of ambient CO_(2).Increase in dissolved carbon in water correlates with the presence of wetland plants since the water hyacinth can directly exchange CO_(2) from the atmosphere to water by the upper epidermis of leaves.Also,the enrichment CO_(2) showed an increase in total carbon and total organic carbon concentration in wetland soil by 3%(p=0.344)and 6%(p=0.008),respectively.The total nitrogen content in water increased by 26%(p=0.0001),while total nitrogen in wetland soil pool under CO_(2) enrichment decreased by 9%(p=0.011)due to increased soil microbial community abundance,extracted by phospholipid fatty acids,which was 25%larger in amount than that of the ambient treatment.Conclusion:The study revealed that the elevated CO_(2) would affect the carbon and nitrogen transformations in wetland plant,water,and soil pool and increase soil microbial community abundance.

Spherical nucleic acids:Organized nucleotide aggregates as versatile nanomedicine

Spherical nucleic acids(SNAs)are composed of a nanoparticle core and a layer of densely arranged oligonucleotide shells.After the first report of SNA by Mirkin and coworkers in 1996,it has created a significant interest by offering new possibilities in the field of gene and drug delivery.The controlled aggregation of oligonucleotides on the surface of organic/inorganic nanoparticles improves the delivery of genes and nucleic acid–based drugs and alters and regulates the biological profiles of the nanoparticle core within living organisms.Here in this review,we present an overview of the recent progress of SNAs that has speeded up their biomedical application and their potential transition to clinical use.We start with introducing the concept and characteristics of SNAs as drug/gene delivery systems and highlight recent efforts of bioengineering SNA by imaging and treatmenting various diseases.Finally,we discuss potential challenges and opportunities of SNAs,their ongoing clinical trials,and future translation,and how they may affect the current landscape of clinical practices.We hope that this review will update our current understanding of SNA,organized oligonucleotide aggregates,for disease diagnosis and treatment.