Ratiometric fluorescent detection of acidic pH in lysosome with carbon nanodots

It is significant for cell physiology to keep the homeostasis of p H, and it is highly demanded to develop ratiometric fluorescent sensors toward p H. In this work, under mild condition, through the electrostatic interaction between carbon nanodots（CDs） and organic molecules, two novel ratiometric fluorescence hybrid nanosensors were fabricated for sensing acidic p H. These nanohybrid systems possess dual emission peaks at 455 and 527 nm under a single excitation wavelength of 380 nm in acidic p H condition.With the increasing of p H, the fluorescence of the 1,8-naphthalimide derivative completely quenches,while the blue fluorescence of CDs keeps constant. Furthermore, the CDsàorganic molecular nanohybrids exhibit excellent anti-disturbance ability, reversible p H sensing ability, and a linear response range in wide p H range respectively. Besides the ability to target lysosome, with one of the nanosensor, stimulated p H change has been successfully tracked in a ratiometric manner via fluorescence imaging.

Drought-Induced Changes in Xylem Sap pH, ABA and Stomatal Conductance

Upstream signals potentially regulating evaporation and stomatal conductance wereinvestigated using 6-8-leaf-old maize (Zea may L.) seedlings which were grown in agreenhouse. Pressure chamber was used to measure leaf water potential and to collectxylem sap. The pH of xylem sap in stems was higher than that in root, and the abscisicacid (ABA) concentration in stems was the highest in well-watered seedlings. The ABAconcentration and pH of xylem sap in roots, stems and leaves increased, and the ABAconcentration in leaves reached the maximum during drought stress. The treatment ofroots with exogenous ABA solution (100molL-1) increased xylem sap ABA concentration inall organs measured, and induced stomatal closure, but did not change ABA distributionamong organs of maize seedlings. The combined effects of external pH buffer on pH, ABAof xylem sap and stomatal behavior indicated that pH, as a root-source signal to leavesunder drought stress, regulated stomatal closure through accumulating ABA in leaves orguard cells.

Removing ammonia from air with a constant pH, slightly acidic water spray wet scrubber using recycled scrubbing solution

Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this studywas to determine if a spray scrubber with slightly acidic and higher p H scrubbing solution （pH from 2 to 8） could effectively remove NH3 from NH3 laden air （such as animal building exhaust air）, and also collect this valuable resource for rater use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH3/air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8while maintaining constant air velocity at 1.3 m. s-1. Next, air velocity was increased （2and 3 m.s-1） while solution pH remained constant at pH6. At 1.3 m.s -1, NH3 removal efficiencies ranged between 49.0% （pH8） and 84.3% （pH2）. This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH3 molecules. The NH3 removed from the air was held in solution as NH4＋ and accumulates over time so the solution should be an excellent fertilizer.

Impact of Stone Enzyme Wash and Acid Wash Based on Denim Garments

The aim of this project is to find out the changes that occur in physical properties of denim when it is subjected to enzyme stone and acid wash or to find out the impact of enzyme stone and acid wash. 97% cotton 3% elastomer twill, weave 3/1, construction 72 × 40/9 × 7 indigo dyed denim fabric leg panels as per lab standard recipe are used here to examine. Firstly, desizing was done as pre-treatments and after treatment was silicon softener. After washing process, different samples from both washing are going to express different behavior on physical properties. This experiment is done to find out the discrimination in tearing strength, shrinkage %, color fastness to wash, color fastness to rubbing, pH rate between stone enzyme wash and acid wash of denim garments.

Characterization of Fe5(AsO3)3Cl2(OH)4·5H2O,a new ferric arsenite hydroxychloride precipitated from FeCl3-As2O3-HCl solutions relevant to arsenic immobilization

Tooeleite(Fe6(As03)4 SO4(OH)4·4 H2 O)is widely precipitated for direct As(III)removal from sulfate-rich industrial effluents.However,whether or not Fe(III)-As(III)-Cl(-I)precipitate is produced in chloridizing leaching media for As immobilization is almost unknown.This work founded the existence of ferric arsenite(hydroxy)chloride as a new mineral for As(III)removal.Its chemical composition and solid characterization were subsequently studied by using scanning electron microscope with an energy dispersive spectrometer(SEM-EDS),X-ray diffraction(XRD),infrared(FT-IR),Raman spectroscopy and thermogravimetric(TG)curve.The results showed the formation of a yellow precipitate after 3-days reaction of Fe(III)/As(III)with molar ratio≈1.7 in chloride solution at pH 2.3 neutralized with NaOH.Compared with tooeleite,chemical analysis and solid characterization indicated that Cl(-I)replaces S04(-II)producing ferric arsenite hydroxychloride with formula Fe5(As03)3-Cl2(OH)4·5 H2 O.This new plate shaped solid showed better crytallinity than tooeleite,although it has similar morphology and characteristic bands to tooeleite.The FT-IR bands at 628,964 cm-1 and the Raman bands at 448,610,961 cm-1 were assigned to Fe-O or As(Ⅲ)-O-Fe or As(Ⅲ)-O bending/stretching vibration,indicating that both arsenite and chloride substituted for the position of sulfate for ferric arsenite hydro xychloride produced due to the lack of the SO42-vibrations.Cl-(I)also contributed to increase As removal efficiency in aqueous sulfate media under acidic pH conditions via the probable formation of sulfatechloride ferric arsenite.

Sorption and cosorption of the nonionic herbicide mefenacet and heavy metals on soil and its components

Sorption and cosorption of the nonionic herbicide mefenacet and two typical metals （copper and silver） on black soil and its components （kaolinite and humic acid） were investigated. It was found that because of their different valences and properties, Cu2＋and Ag＋ presented different effects on the sorption of mefenacet. Due to the competition of Cu2＋, along with the shells of dense water formed by its surface complexation, for sorption surface area with mefenacet, the addition of Cu2＋ decreased the sorption amount of mefenacet on soil and its components, especially on humic acid. However, the addition of Ag＋ significantly enhanced the sorption of mefenacet, which was attributed to the softness of the cation that weakened the hydrophilicity of the local region around Ag＋-complexed functionalities, and thus mitigated the competitive sorption of water. In addition, the sorption of mefenacet on soil with or without the two metals was generally decreased with increasing pH, which was caused by the hydrolysis of carbonyl and carboxyl groups on the surface of the sorbents, π-π interaction between mefenacet and the soil organic matter, and so on. On the other hand, the presence of mefenacet seemed to have little effect on the sorption of Cu2＋ and Ag＋, indicating that Cu2＋ and Ag＋ might be sorbed strongly on the tested sorbents and the mefenacet added was too low in concentration to affect the sorption of the metals.

Determining short chain fatty acids in sewage sludge hydrolysate: A comparison of three analytical methods and investigation of sample storage effects

In anaerobic digestion, the production of short-chain fatty acids （SCFAs） can be beneficial or harmful to the overall process, depending on the concentration of accumulated acids. Therefore, the accurate determination of the SCFA concentration in both fresh and stored sludge hydrolysates is important. To select a suitable method for monitoring SCFAs during the anaerobic digestion of sewage sludge, the accuracy of three available analytical methods, including 5 pH point acid titration （TITRA5）, gas chromatography （GC）, and spectrophotometry, were compared in the present study. The results revealed that TITRA5 and GC displayed better agreement in the achieved measurements and higher precision and accuracy than the spectrophotometric assay, as supported by the application of different statistical models. TITRA5 excelled in titrating unfiltered hydrolysate while simultaneously measuring the alkalinity, whereas the GC method provided detailed information on the contribution of different fatty acids to the total acidity. In contrast, the spectrophotometric assay suffered from many forms of interference, depending on the sample＇s matrix. SCFA production followed the pattern of enzymatic reactions and fitted the Michaelis-Menten model. In addition to promoting TITRA5 as an accurate and robust analytical tool for routine SCFA analyses, this comparative study also demonstrated the possibility of storing hydrolysate samples at different temperatures and durations without altering the SCFA measurements.