Increase in acid sphingomyelinase level in human retinal endothelial cells and CD34+ circulating angiogenic cells isolated from diabetic individuals is associated with dysfunctional retinal vasculature and vascular repair process in diabetes

BACKGROUND: Diabetic retinopathy is a microvascular disease that results from retinal vascular degeneration and defective repair due to diabetes-induced endothelial progenitor dysfunction. OBJECTIVE: Understanding key molecular factors involved in vascular degeneration and repair is paramount for developing effective diabetic retinopathy treatment strategies. We propose that diabetes-induced activation of acid sphingomyelinase (ASM) plays essential role in retinal endothelial and CD34+ circulating angiogenic cell (CAC) dysfunction in diabetes. METHODS: Human retinal endothelial cells (HRECs) isolated from control and diabetic donor tissue and human CD34+ CACs from control and diabetic patients were used in this study. ASM messenger RNA and protein expression were assessed by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. To evaluate the effect of diabetes-induced ASM on HRECs and CD34+ CACs function, tube formation, CAC incorporation into endothelial tubes, and diurnal release of CD34+ CACs in diabetic individuals were determined. RESULTS: ASM expression level was significantly increased in HRECs isolated from diabetic compared with control donor tissue, as well as CD34+ CACs and plasma of diabetic patients. A significant decrease in tube area was observed in HRECs from diabetic donors compared with control HRECs. The tube formation deficiency was associated with increased expression of ASM in diabetic HRECs. Moreover, diabetic CD34+ CACs with high ASM showed defective incorporation into endothelial tubes. Diurnal release of CD34+ CACs was disrupted with the rhythmicity lost in diabetic patients. CONCLUSION: Collectively, these findings support that diabetes-induced ASM upregulation has a marked detrimental effect on both retinal endothelial cells and CACs

Optimization of fixation methods for observation of bacterial cell morphology and surface ultrastructures by atomic force microscopy

Fixation ability of five common fixation solutions, including 2.5% glutaraldehyde, 10% formalin, 4% paraformaldehyde, methanol/acetone (1:1), and ethanol/acetic acid (3:1) were evaluated by using atomic force microscopy in the present study. Three model bacteria, i.e., Escherichia coli, Pseudomonas putida, and Bacillus subtilis were applied to observe the above fixation methods for the morphology preservation of bacterial cells and surface ultrastructures. All the fixation methods could effectively preserve cell morphology. However, for preserving bacterial surface ultrastructures, the methods applying aldehyde fixations performed much better than those using alcohols, since the alcohols could detach the surface filaments (i.e., flagella and pili) significantly. Based on the quantitative and qualitative assessments, the 2.5% glutaraldehyde was proposed as a promising fixation solution both for observing morphology of both bacterial cell and surface ultrastructures, while the methonal/acetone mixture was the worst fixation solution which may obtain unreliable results

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Studies of biofilm development by advanced microscopic techniques and high-throughput sequencing

This study was conducted to investigate the biofilm formation by using advanced microscopic and high-throughput sequencing techniques. The major tasks were (1) to quantitatively evaluate the initial bacterial attachment processes by Atomic Force Microscopy (AFM); (2) to characterize the chemical variation during biofilm formation by Raman microscopy; (3) to analyze the microbial structure and functions in the wastewater and drinking water biofilms by metagenomic analysis. To determine the lateral detachment force for bacteria, a quantitative method using contact mode of AFM was developed. The established method had good repeatability and sensitivity to various bacteria and substrata, and was applied to evaluate the roles of bacterial surface polymers in Phase I and II attachment, i.e. lipopolysaccharides, type 1 fimbria and capsular colanic acid. The results indicated lipopolysaccharides largely enhanced Phases I and II attachment. Fimbriae increased Phase I attachment but not significantly influence the adhesion strength in Phase II. Moreover, colanic acid had negative effect on attachment in both of Phases I and II. Surface-enhanced Raman scattering was applied to evaluate the chemical components in the biofilm matrix at different growth phases, including initial attached bacteria, colonies and mature biofilm. Three model bacteria, including Escherichia coli, Pseudomonas putida, and Bacillus subtilis, were used to cultivate biofilms. The results showed that the content of carbohydrates, proteins, and nucleic acids in biofilm matrix increased significantly along with the biofilm growth of three bacteria judging from the intensities and appearance probabilities of related marker peaks in the spectra. The content of lipids, however, only increased in the Gram-negative biofilms. Moreover, metagenomic data, coupled with PCR-based 454 pyrosequencing reads, were generated for activated sludge and biofilm from a full-scale hybrid reactor to study the microbial taxonomic and functional differences/connections between activated sludge and biofilm. The results showed that the dominant bacteria co-existed in two samples. Global functions in activated sludge and biofilm metagenomes showed quite similar pattern, revealing the limited differences of overall functions existed in two samples. For nitrogen removal, the diversity and abundance of nitrifiers and denitrifiers in biofilm did not surpass that in activated sludge. Whilst, higher abundances of nitrification and denitrification genes were indeed found in biofilm, suggesting the increased nitrogen removal by applying biofilm might be attributed to removal efficiency rather than biomass accumulation of nitrogen removal bacteria. To investigate the bacterial structure and functions of drinking water biofilm, PCR-based 454 pyrosequencing of 16S rRNA gene and Illumina metagenomic data were generated and analyzed. Significant differences of bacterial diversity and taxonomic structure were found between biofilms formed on stainless steel and plastics. Moreover, ecological succession could be obviously observed during biofilm formation. The metabolic network analysis for drinking water biofilm constructed for the first time. Moreover, the occurrence and abundance of specific genes involving in the bacterial pathway of glutathione metabolism and production/degradation of extracellular polymeric substances were also evaluated.published_or_final_versionCivil EngineeringDoctoralDoctor of Philosoph

Urban CO2 emissions in Xi'an and Bangalore by commuters: implications for controlling urban transportation carbon dioxide emissions in developing countries

China and India together have more than one third of the world population and are two emerging economic giants of the developing world now experiencing rapid economic growth, urbanization, and motorization. The urban transportation sector is a major source of carbon dioxide (CO2) emissions in China and India. The goal of this study is to analyze the characteristics and factors of CO2 emissions produced by commuters in Chinese and Indian cities and thus to identify strategies for reducing transportation CO2 emissions and mitigating global climate change. Xi'an in China and Bangalore in India were chosen as two case study cities for their representativeness of major cities in China and India. The trends of CO2 emissions produced by major traffic modes (electric motors, buses, and cars) in major cities of China and India were predicted and analyzed. The spatial distributions of CO2 emissions produced by commuters in both cities were assessed using spatial analysis module in ArcGIS (Geographic Information System) software. Tobit models were then developed to investigate the impact factors of the emissions. The study has several findings. Firstly, in both cities, the increase of vehicle occupancy could reduce commuting CO2 emissions by 20 to 50 % or conversely, if vehicle occupancy reduces, an increase by 33.33 to 66.67 %. It is estimated that, with the current increasing speed of CO2 emissions in Xi'an, the total CO2 emissions from electric motors, buses, and cars in major cities of China and India will be increased from 135 x 10(6) t in 2012 to 961x 10(6) t in 2030, accounting for 0.37 to 2.67 % of the total global CO2 emissions of 2013, which is significant for global climate change. Secondly, households and individuals in the outer areas of both cities produce higher emissions than those in the inner areas. Thirdly, the lower emissions in Xi'an are due to the higher density and more compact urban pattern, shorter commuting distances, higher transit shares, and more clean energy vehicles. The more dispersed and extensive urban sprawl and the prevalence of twowheeler motorbikes (two-wheeler motorbike is abbreviated as Btwo-wheeler<\^> in the following sections) fueled by gasoline cause higher emissions in Bangalore. Fourthly, car availability, higher household income, living outside the 2nd or Outer Ring Road, distance from the bus stop, and working in the foreign companies in Bangalore are significant and positive factors of commuting CO2 emissions. Fifthly, ``70-20'' and ``50-20'' (this means that generally, 20 % of commuters and households produce 70 % of total emissions in Xi'an and 20 % of commuters and households produce 50 % of total emissions in Bangalore) emission patterns exist in Xi'an and Bangalore, respectively. Several strategies have been proposed to reduce urban CO2 emissions produced by commuters and further to mitigate global climate change. Firstly, in the early stage of fast urbanization, enough monetary and land investment should be ensured to develop rail transit or rapid bus routes from outer areas to inner areas in the cities to avoid high dependency on cars, thus to implement the transit-oriented development (TOD), which is the key for Chinese and Indian cities to mitigate the impact on global climate change caused by CO2 emissions. Secondly, in Bangalore, it is necessary to improve public transit service and increase the bus stop coverage combined with car demand controls along the ring roads, in the outer areas, and in the industry areas where Indian foreign companies and the governments are located. Thirdly, Indian should put more efforts to provide alternative cleaner transport modes while China should put more efforts to reduce CO2 emissions from high emitter

Tuning Wet Adhesion of Weak Polyelectrolyte Multilayers

Weak polyelectrolyte multilayers (PEMs) assembled by the layer-by-layer method are known to become tacky upon contact with water and behave as a viscoelastic fluid, but this wet adhesive property and how it can be modified by external stimuli has not yet been fully explored. We present here a study on the wet adhesive performance of PEMs consisting of branched poly­(ethylene imine) and poly­(acrylic acid) under controlled conditions (e.g., pH, type of salt, and ionic strength) using a 90° peel test. The multilayers demonstrate stick–slip behavior and fail cohesively in nearly all cases. The peel force is the highest at neutral pH, and it decreases in both acidic/basic environments because of inhibited polyelectrolyte mobility. The addition of salts with various metal ions generally reduces the peel force, and this effect tracks with the ionic strength. When transition metal ions are used, their ability to form coordination bonds increases the peel force, with two exceptions (Cu²⁺ and Zn²⁺). With a transition metal ion such as Fe³⁺, the peel force first increases as a function of the concentration and then eventually decreases. The peel force increases proportionally to the peel rate. The films are also characterized via zeta potential (when assembled onto colloidal particles) and shear rheometry. This work provides insight into both the wet adhesive properties of PEMs and the interactions between PEMs and metal ions

Tuning Wet Adhesion of Weak Polyelectrolyte Multilayers

Weak polyelectrolyte multilayers (PEMs) assembled by the layer-by-layer method are known to become tacky upon contact with water and behave as a viscoelastic fluid, but this wet adhesive property and how it can be modified by external stimuli has not yet been fully explored. We present here a study on the wet adhesive performance of PEMs consisting of branched poly­(ethylene imine) and poly­(acrylic acid) under controlled conditions (e.g., pH, type of salt, and ionic strength) using a 90° peel test. The multilayers demonstrate stick–slip behavior and fail cohesively in nearly all cases. The peel force is the highest at neutral pH, and it decreases in both acidic/basic environments because of inhibited polyelectrolyte mobility. The addition of salts with various metal ions generally reduces the peel force, and this effect tracks with the ionic strength. When transition metal ions are used, their ability to form coordination bonds increases the peel force, with two exceptions (Cu²⁺ and Zn²⁺). With a transition metal ion such as Fe³⁺, the peel force first increases as a function of the concentration and then eventually decreases. The peel force increases proportionally to the peel rate. The films are also characterized via zeta potential (when assembled onto colloidal particles) and shear rheometry. This work provides insight into both the wet adhesive properties of PEMs and the interactions between PEMs and metal ions

Tuning Wet Adhesion of Weak Polyelectrolyte Multilayers

Weak polyelectrolyte multilayers (PEMs) assembled by the layer-by-layer method are known to become tacky upon contact with water and behave as a viscoelastic fluid, but this wet adhesive property and how it can be modified by external stimuli has not yet been fully explored. We present here a study on the wet adhesive performance of PEMs consisting of branched poly­(ethylene imine) and poly­(acrylic acid) under controlled conditions (e.g., pH, type of salt, and ionic strength) using a 90° peel test. The multilayers demonstrate stick–slip behavior and fail cohesively in nearly all cases. The peel force is the highest at neutral pH, and it decreases in both acidic/basic environments because of inhibited polyelectrolyte mobility. The addition of salts with various metal ions generally reduces the peel force, and this effect tracks with the ionic strength. When transition metal ions are used, their ability to form coordination bonds increases the peel force, with two exceptions (Cu²⁺ and Zn²⁺). With a transition metal ion such as Fe³⁺, the peel force first increases as a function of the concentration and then eventually decreases. The peel force increases proportionally to the peel rate. The films are also characterized via zeta potential (when assembled onto colloidal particles) and shear rheometry. This work provides insight into both the wet adhesive properties of PEMs and the interactions between PEMs and metal ions

Potential of Cassia alata L. Coupled with Biochar for Heavy Metal Stabilization in Multi-Metal Mine Tailings

To explore the effect of different biochars on Cassia alata L. growth and heavy metal immobilization in multi-metal mine tailings, a 100-day pot experiment was conducted. Three biochars derived from Hibiscus cannabinus core (HB), sewage sludge (SB) and chicken manure (MB), were added to mine tailings at rates of 0.4%, 1% and 3% (w/w). The results showed that the root biomass, shoot biomass, plant height and root length were 1.2–2.8, 1.7–3.2, 1–1.5 and 1.6–3.3 times of those in the control group, respectively. Pb, Zn, Cu, Cd and As contents in the shoot decreased by 63.9–89.5%, 46.9–66.0%, 32.7–62.4%, 40.4–76.4% and 54.9–77.5%, respectively. The biochar significantly increased the pH and decreased the mild acid-soluble Pb and Cu concentrations in the mine tailings. Specifically, SB immobilized Pb and Cu better than MB and HB did, although it did not immobilize As, Zn or Cd. Meanwhile, more attention should be paid to the potential As release as the biochar application rate increases. In conclusion, Cassia alata L. coupled with 3% of SB could be an effective measure for restoring multi-metal mine tailings. This study herein provided a promising ecological restoration technique for future practice of heavy metal stabilization in mine tailings