Bathing Solution Research Articles

Activation of Piezo1 Increases Na,K-ATPase-Mediated Ion Transport in Mouse Lens.

Lens ion homeostasis depends on Na,K-ATPase and NKCC1. TRPV4 and TRPV1 channels, which are mechanosensitive, play important roles in mechanisms that regulate the activity of these transporters. Here, we examined another mechanosensitive channel, piezo1, which is also expressed in the lens. The purpose of the study was to examine piezo1 function. Recognizing that activation of TRPV4 and TRPV1 causes changes in lens ion transport mechanisms, we carried out studies to determine whether piezo1 activation changes either Na,K-ATPase-mediated or NKCC1-mediated ion transport. We also examined channel function of piezo1 by measuring calcium entry. Rb uptake was measured as an index of inwardly directed potassium transport by intact mouse lenses. Intracellular calcium concentration was measured in Fura-2 loaded cells by a ratiometric imaging technique. Piezo1 immunolocalization was most evident in the lens epithelium. Potassium (Rb) uptake was increased in intact lenses as well as in cultured lens epithelium exposed to Yoda1, a piezo1 agonist. The majority of Rb uptake is Na,K-ATPase-dependent, although there also is a significant NKCC-dependent component. In the presence of ouabain, an Na,K-ATPase inhibitor, Yoda1 did not increase Rb uptake. In contrast, Yoda1 increased Rb uptake to a similar degree in the presence or absence of 1 µM bumetanide, an NKCC inhibitor. The Rb uptake response to Yoda1 was inhibited by the selective piezo1 antagonist GsMTx4, and also by the nonselective antagonists ruthenium red and gadolinium. In parallel studies, Yoda1 was observed to increase cytoplasmic calcium concentration in cells loaded with Fura-2. The calcium response to Yoda1 was abolished by gadolinium or ruthenium red. The calcium and Rb uptake responses to Yoda1 were absent in calcium-free bathing solution, consistent with calcium entry when piezo1 is activated. Taken together, these findings point to stimulation of Na,K-ATPase, but not NKCC, when piezo1 is activated. Na,K-ATPase is the principal mechanism responsible for ion and water homeostasis in the lens. The functional role of lens piezo1 is a topic for further study.

Electrochemical deposition of nickel from local nickel sulphate solution on copper substrate

In this work, nickel was deposited on copper substrate through electrodeposition which was abstracted from local sulphate salt. Nickel deposition on copper substrate was done in both presence of vitamin C and saccharin additive. Boric oxide was used as buffering agent and pH of the solution bath was maintained through sulfuric acid and ammonium hydroxide. Round shape deposition on copper substrate was observed in the presence of vitamin C, while columnar shape particles were observed in the presence of saccharin additive. Deposition of nickel was done through sulfate bath on copper substrate. Boric acid was used as buffering agent and direct current electrolysis were conduct throughout this experimental work. pH of the solution was kept constant with the help of diluted sulfuric acid and ammonium hydroxide. The deposited nickel particles were obtained in round shape in the presence of vitamin additive, while columnar shape particles obtained in saccharin additive. The experimental conditions were optimizing to get smooth, adherent, and acid resistance surface. This research work reported that, rate of sulfate bath deposition increases lineally with increase in temperature and pH of the solution.

Impact of Goreisan components on rat mesenteric collecting lymphatic vessel pumping.

Goreisan is a traditional herbal formulation with diuretic properties tested as a clinical therapeutic to alleviate lymphedema in Japan. The present study aimed to determine how Goreisan and its five different components affect lymphatic pump function. Mesenteric collecting lymphatics were isolated from anesthetized Sprague-Dawley rats and mounted on resistance-matched glass micropipettes in a 37°C physiological salt solution bath for studies. Diameter was continuously measured to obtain the following lymphatic pump parameters: contraction frequency (CF), end diastolic diameter (EDD), and end systolic diameter (ESD), contraction amplitude (AMP), ejection fraction (EF), and fractional pump flow (FPF). Goreisan and each of its components (Cinnamomi Cortex, Atractylodis Rhizoma, Alismatis Rhizoma, Polyporus, and Poria) were applied to the bath at concentrations of 1-30 μg/mL. The results show that while Goreisan causes no significant changes to lymphatic pumping, Alismatis Rhizoma and Polyporus each significantly reduce CF and FPF. In addition, rats that received oral administration of Goreisan and Alismatis Rhizoma for 1 week had elevated expression of VEGFR-3 in their mesenteric collecting lymphatics. Collectively, the results suggest that some components of Goreisan have a direct, rapid impact on lymphatic pumping. These findings provide new insights but also raise new questions about the therapeutic potential of Goreisan in patients with secondary lymphedema.

Physically Cross-linked nanocellulose composites tailored from base bath and ferric (III) ion: Mechanical, water resistance and thermal property

The development of sustainable composites from wood derived cellulose nanocrystals (CNCs) and degradable poly(vinyl alcohol)-PVA polymer is a promising strategy to resolve the issue of plastic pollution, which is also consistent with the current carbon neutrality and sustainable development tendency. However, the strong intra- or inter-molecular hydrogen bonding interactions of CNCs endow it with poor processability, resulting in the composites with unsatisfied comprehensive performance. Therefore, a novel method developed from base bath solutions and ferric (III) ion was reported to construct the physical cross-linking (e.g., hydrogen bonding and coordination interactions) to improve the water resistance, thermal and mechanical performance of PVA/CNC composites. For the comparison with the counterparts without cross-linking, the Young’s modulus and tensile strength of physically cross-linked PVA/CNC composites were obviously increased. Meanwhile, the thermal and water resistance property of physically cross-linked composites was also obviously improved owing to the physical interactions, e.g., hydrogen bonding and ferric (III) ion-carboxyl group coordination interactions. The results above provided the basis for the further exploration of direct ink writing 3D/4D printing sustainable nanocellulose composites.

Effect of temperature on structural, optical, and morphological properties of ED-CdTe thin film

On fluorine-doped tin oxide (FTO) coated glass substrates, CdTe thin films were electrodeposited (ED) using an aqueous electrolyte bath solution. The temperature value of the electrolyte solution is one of the most important deposition parameters that should be adjusted to produce good quality photoconductive material. In our study, the films have been deposited at a different temperatures ranging from 50 to 70°C. Structural properties of the CdTe thin films were characterized using X-ray diffraction (XRD), and using UV–Visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX) techniques, and the optical and morphological properties were studied. The cubic crystalline structure of the ED-CdTe films is confirmed by the XRD analysis, and as the temperature is changed, the diffraction peak intensity significantly increased. In optical absorption spectra, the direct energy band-gap (Eg=1.48eV) is obtained. By adjusting the temperatures, the SEM analysis proves very good morphological growth, and the EDX study confirmed the atomic composition of the CdTe layers.

Mannan-binding lectin serine protease-2 (MASP-2) in human kidney and its relevance for proteolytic activation of the epithelial sodium channel

Proteolytic activation of the renal epithelial sodium channel (ENaC) is increased by aldosterone. The aldosterone-sensitive protease remains unidentified. In humans, elevated circulating aldosterone is associated with increased urinary extracellular vesicle (uEVs) excretion of mannan-binding lectin associated serine protease-2 (MASP-2). We hypothesized that MASP-2 is a physiologically relevant ENaC-activating protease. It was confirmed that MASP2 mRNA is abundantly present in liver but not in human and mouse kidneys. Aldosterone-stimulation of murine cortical colleting duct (mCCD) cells did not induce MASP-2 mRNA. In human kidney collecting duct, MASP-2 protein was detected in AQP2-negative/ATP6VB1-positive intercalated cells suggestive of MASP2 protein uptake. Plasma concentration of full-length MASP-2 and the short splice variant MAp19 were not changed in a cross-over intervention study in healthy humans with low (70 mmol/day) versus high (250 mmol/day) Na+ intake despite changes in aldosterone. The ratio of MAp19/MASP-2 in plasma was significantly increased with a high Na+ diet and the ratio correlated with changes in aldosterone and fractional Na+ excretion. MASP-2 was not detected in crude urine or in uEVs. MASP2 activated an amiloride-sensitive current when co-expressed with ENaC in Xenopus oocytes, but not when added to the bath solution. In monolayers of collecting duct M1 cells, MASP2 expression did not increase amiloride-sensitive current and in HEK293 cells, MASP-2 did not affect γENaC cleavage. MASP-2 is neither expressed nor co-localized and co-regulated with ENaC in the human kidney or in urine after low Na+ intake. MASP-2 does not mediate physiological ENaC cleavage in low salt/high aldosterone settings.

Investigation on electrochemical deposition of Sb2Se3 thin films in aqueous acidic medium

• Thin films of Sb 2 Se 3 have been synthesized by electro-deposition method. • Bath pH and applied potential have a sizable effect on the films quality. • Annealing process is required to control the crystallization of Sb2Se3 thin films. • The suitable band gap of 1.23 eV for the solar cells is reached. Antimony selenide (Sb 2 Se 3 ) thin films were deposited on tin oxide coated glass substrates by potentiostatic electrodeposition from an acidic aqueous bath for 30 min followed by the annealing process in a tube furnace at 350 °C for 10 min under nitrogen atmosphere. The aim of this work is to investigate the effect of the bath solution's pH and the applied potential on the structural, morphological, compositional and optical properties of Sb 2 Se 3 thin films. The optimal deposition conditions and bath acidity were identified to produce good quality Sb 2 Se 3 films suitable for applications in terms of composition, crystallinity, morphology and band gap.

Application of interval arithmetic in numerical modeling of cryopreservation process during cryoprotectant loading to microchamber

This article presents numerical modeling of the heat and mass exchange occurring in a two-dimensional axially symmetric articular cartilage sample submerged in a microchamber into CPTes2 bathing solution undergoing cryopreservation. In the considered mathematical model, the parameters defined as interval numbers were assumed. The heat transfer process was described by the interval Fourier equation, the transport of cryoprotectant (CPA) through the cell membrane was given by a two-parameter model including the simulation of H2O volume in chondrocytes and the change of DMSO concentration in time. In addition, the transport of CPA via microchannels to the sample in the microchamber was descripted by the Navier-Stokes equation. The model uses the liquidus tracking (LT) protocol introduced by Pegg et al. and refined by Yu et al. This approach regulates both the temperature and the concentration of CPA in the bathing solution. The protocol protects chondrocytes from ice crystal, osmotic stress, and electrolyte damage. The entire cryopreservation process considered is divided into 7 periods in the cooling and CPA supply phase and 6 periods in the heating and CPA removal phase, which allows precise regulation of the temperature and cryoprotectant (CPA) concentration in the bath solutions. In the final part of the article the results of numerical simulations are presented.

ZnFe2O4/ ZnO 0D-1D heterojunction for efficient photoelectrochemical water splitting

In this work, both ZnO nanorods (NRs) thin films and ZnO NRs powder were successfully synthesized by open aqueous solution bath technique. Further, the residual ZnO nanorods (NRs) powder was used to synthesize ZnFe2O4 (ZFO) nanoparticles (NPs) by hydrothermal method. Finally, ZFO/ZnO heterojunction thin films were prepared and tested for photoelectrochemical water splitting application. The ZFO loading was controlled and tuned by drop-casting various numbers of drops (10, 20, 30 and 40) on the ZnO NRs films keeping the area constant. An improved photocurrent density ∼0.82 mA/cm2 was observed for optimized 30 ZFO/ZnO NRs thin films as compared to ∼0.19 mA/cm2 for pristine ZnO NRs thin films at 1.23 V vs RHE under 100 mW/cm2 light in a 0.1 M Na2SO4 neutral electrolyte. This remarkable enhancement in photocurrent for 30 ZFO/ZnO heterojunction compared to pure ZnO NRs array is attributed to increased light absorption induced electron-hole pairs generation, effective charge transfer and better charge separation at the ZFO/ZnO interface due to a favorable band alignment. This was confirmed with the incident photon to current conversion efficiency (IPCE) measurements which exhibit a significantly high value (∼14%) for 30 ZFO/ZnO films than pristine ZFO and ZnO thin films. It is worthy to note that ZFO NPs coated ZnO thin films deliver long term stability of the electrode against photocorrosion.

Intracellular Binding of Terfenadine Competes with Its Access to Pancreatic ß-cell ATP-Sensitive K+ Channels and Human ether-à-go-go-Related Gene Channels

Most blockers of both hERG (human ether-à-go-go-related gene) channels and pancreatic ß-cell ATP-sensitive K+ (KATP) channels access their binding sites from the cytoplasmic side of the plasma membrane. It is unknown whether binding to intracellular components competes with binding of these substances to K+ channels. The whole-cell configuration of the patch-clamp technique, a laser-scanning confocal microscope, and fluorescence correlation spectroscopy (FCS) were used to study hERG channels expressed in HEK (human embryonic kidney) 293 cells and KATP channels from the clonal insulinoma cell line RINm5F. When applied via the pipette solution in the whole-cell configuration, terfenadine blocked both hERG and KATP currents with much lower potency than after application via the bath solution, which was not due to P-glycoprotein-mediated efflux of terfenadine. Such a difference was not observed with dofetilide and tolbutamide. 37–68% of hERG/EGFP (enhanced green-fluorescent protein) fusion proteins expressed in HEK 293 cells were slowly diffusible as determined by laser-scanning microscopy in the whole-cell configuration and by FCS in intact cells. Bath application of a green-fluorescent sulphonylurea derivative (Bodipy-glibenclamide) induced a diffuse fluorescence in the cytosol of RINm5F cells under whole-cell patch-clamp conditions. These observations demonstrate the presence of intracellular binding sites for hERG and KATP channel blockers not dialyzable by the patch-pipette solution. Intracellular binding of terfenadine was not influenced by a mutated hERG (Y652A) channel. In conclusion, substances with high lipophilicity are not freely diffusible inside the cell but steep concentration gradients might exist within the cell and in the sub-membrane space.Graphical

Effect of pH in Coagulation Bath on Polysulfone-based Membrane Formation and Its Performance Characteristics

One of the factors that determine the formation of the membrane is the solution in the coagulation bath (non-solvent). In this study, the effect of pH treatment on the coagulation bath solution on membrane formation and its effect on membrane performance will be studied. The pH of the coagulation bath used was pH 1, 6.8 and 12. As the results, physically the three pH treatments produced the same white (opaque) membrane. Through morphological analysis, it appears that the three pH treatments produced an asymmetric membrane consisting of a top layer and a sublayer. The surface of the membrane with pH 1 treatment showed a denser surface than the pH 6.8 and pH 12 treatments. The results of the membrane performance characterization showed that the membrane permeability coefficient of the membrane with pH treatment was in the following order pH 1 < pH 12 < pH 6.8. While the value of the rejection coefficient showed that the membrane treated at pH 1 did not detect rejection because there was no permeate coming out, while at the treatment at pH 6.8 and 12, the rejection coefficient values were 74% and 76%, respectively.

Vibegron inhibits enhanced spontaneous contractions induced by anoxia/reoxygenation in isolated whole bladder from rats

It has been recently proposed that repeated bladder ischemia/reperfusion induced by chronic pelvic ischemia may lead to detrusor overactivity, followed by lower urinary tract symptoms. Vibegron is a selective β3-adrenoceptor agonist approved for the treatment of overactive bladder. Several studies have tested β3-adrenoceptor agonists using animal models with detrusor overactivity related to bladder ischemia/reperfusion. However, whether β3-adrenoceptor agonists directly affect ischemia/reperfusion-evoked detrusor overactivity is unclear. Therefore, we examined whether bladder anoxia/reoxygenation could enhance spontaneous bladder contractions (SBCs) and investigated the effect of vibegron on enhanced SBCs. Isolated whole bladders from rats were incubated with Krebs solution aerated with 95% N2 + 5% CO2 for 5 h (anoxia). Subsequently, the bathing solution was replaced with an oxygen-saturated solution (reoxygenation). Anoxia/reoxygenation caused enhancement of the amplitude but not the frequency of SBC compared with that before reoxygenation. Vibegron (0.3–30 μM) inhibited this increase in SBC amplitude, but not the frequency, in a dose-dependent manner. The inhibitory effect of vibegron was not affected by pretreatment with the adenylyl cyclase inhibitor SQ22536 (100 μM) or protein kinase A inhibitor KT5720 (1 μM) and was not accompanied by considerable changes in cyclic adenosine monophosphate (cAMP) content in the bladder. In contrast, the large conductance potassium channel inhibitor iberiotoxin (100 nM) suppressed the inhibitory effect of vibegron. These results suggest that bladder ischemia/reperfusion induces SBC enhancement and vibegron directly inhibits detrusor overactivity via the large conductance potassium channel, which involves β3-adrenoceptor, rather than the cAMP signaling pathway.

Electrochemical Corrosion Behaviour of Nickel and Nickel-Reduced Graphene Oxide Coatings on Mild Steel in 3.5% NaCl Solution

Nickel-based electrodeposits are extensively used to protect mild steel. The graphene-based materials as corrosion resistive coatings for metallic substrates have been attracted researchers due to their ability to prevent the metal surface. Herein, nickel and nickel reduced graphene oxide (Ni-rGO) composite coatings have been electrodeposited on mild steel using sulphate bath solution. The morphological results reveal that the Ni-rGO coatings exhibited a smaller grain size with less surface defects. It was observed from the scanning electron micrographs images that composite coatings are porous free. The anti-corrosion properties of coatings were further examined by salt spray test. The electrochemical polarization and impedance measurements revealed that Ni-rGO coating enhances the corrosion resistance of mild steel. Electrochemical measurements revealed that the insertion of a few-layered rGO to the Ni matrix increases the corrosion resistance properties of the Ni-rGO coatings.

Rehydration of the Tendon Fascicle Bundles Using Simulated Body Fluid Ensures Stable Mechanical Properties of the Samples.

In this work, we investigate the influence of dehydration and subsequent rehydration of tendon fascicle bundles on their structural and mechanical properties by using distilled water, 0.9% NaCl, 10% NaCl, SBF, and double concentrated SBF (SBFx2). The properties of tendon fascicle bundles were investigated by means of uniaxial tests with relaxation periods and hysteresis for samples with various interfascicular matrix content, dissected from the anterior and posterior areas of bovine tendon. Uniaxial tests with relaxation periods and analysis of sample geometry and weight showed that dehydration alters the modulus of elasticity dependent on the interfascicular matrix content and influences the viscoelastic properties of tendon fascicle bundles. Tensile and relaxation tests revealed that changes resulting from excessive sample drying can be reversed by rehydration in an SBF bath solution for elastic strain range above the toe region. Rehydration in SBF solution led to minor differences in mechanical properties when compared to control samples. Moreover, anterior samples with greater interfascicular matrix content, despite their lower stiffness, are less sensitive to sample drying. The obtained results allow us to limit the discrepancies in the measurement of mechanical properties of wet biological samples and can be useful to researchers investigating soft tissue mechanics and the stability of transplant materials.

Enhanced mechanical properties and corrosion resistance of nickel and nickel-phosphorous coatings fabricated by electrodeposition embedding with TiB2 ceramic particles

Pure nickel (Ni), TiB2 reinforced nickel (Ni-TiB2), nickel-phosphorus (Ni-P), and TiB2 reinforced nickel-phosphorus (Ni-P-TiB2) composite coatings were deposited on AISI-1045 steel substrates from Watts bath and phosphorous-containing solution, respectively. The composition and microstructure of these coatings were analyzed by energy dispersive x-ray spectroscopy (EDS), scanning electron microscope (SEM) and x-ray diffraction (XRD) analysis. The properties of these coatings, including hardness, were assessed and compared. The electrochemical performance of these coatings was investigated in a 3.5 wt% sodium chloride solution using electrochemical spectroscopy (EIS) and the potentiodynamic polarization technique at room temperature. The effect of TiB2 on the microstructure, phase, and properties of the coatings was investigated. The results indicate that the incorporation of TiB2 particles in the nickel matrix greatly increased the hardness and anti-corrosion properties of the nickel coatings by refining of the microstructure and reducing the defects. The enhancement effect of TiB2 on Ni-P coating is not as significant as that of TiB2 on nickel coating. However, with the incorporation of TiB2 ceramic particles, the corrosion resistance and hardness of the Ni-P-TiB2 coating increased by about 50% and 10%, respectively, compared with the original Ni-P coating. The present study provides insight into the potential applications of novel TiB2 ceramic particle-reinforced nickel composite coatings in the areas of wear and corrosion resistance.

Confocal Microscopy to Measure Three Modes of Fusion Pore Dynamics in Adrenal Chromaffin Cells.

Dynamic fusion pore opening and closure mediate exocytosis and endocytosis and determine their kinetics. Here, it is demonstrated in detail how confocal microscopy was used in combination with patch-clamp recording to detect three fusion modes in primary culture bovine adrenal chromaffin cells. The three fusion modes include 1) close-fusion (also called kiss-and-run), involving fusion pore opening and closure, 2) stay-fusion, involving fusion pore opening and maintaining the opened pore, and 3) shrink-fusion, involving shrinkage of the fusion-generated Ω-shape profile until it merges completely at the plasma membrane. To detect these fusion modes, the plasma membrane was labeled by overexpressing mNeonGreen attached with the PH domain of phospholipase C δ (PH-mNG), which binds to phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) at the cytosol-facing leaflet of the plasma membrane; vesicles were loaded with the fluorescent false neurotransmitter FFN511 to detect vesicular content release; and Atto 655 was included in the bath solution to detect fusion pore closure. These three fluorescent probes were imaged simultaneously at ~20-90 ms per frame in live chromaffin cells to detect fusion pore opening, content release, fusion pore closure, and fusing vesicle size changes. The analysis method is described to distinguish three fusion modes from these fluorescence measurements. The method described here can, in principle, apply to many secretory cells beyond chromaffin cells.

Sodium Nitroprusside-Induced Activation of Vascular Smooth Muscle BK Channels Is Mediated by PKG Rather Than by a Direct Interaction with NO

Nitric oxide (NO) is a powerful vasodilator in different vascular beds and NO-donors are widely used in clinical practice. Early data suggested that NO and NO-donors activate vascular smooth muscle high-conductance, calcium-activated potassium channels (BK channels). There exist two hypotheses explaining the effect of NO and NO-donors on BK channels—one stating that protein kinase G (PKG) mediates the effect of NO, and the other one stating that NO acts directly on the channel. Thus, the degree of contribution of PKG to the NO-induced activation of the BK channel is still not completely clear. This study tested the hypothesis that the sodium nitroprusside (SNP)-induced activation of vascular smooth muscle BK channels is fully mediated by PKG. This hypothesis was investigated using the patch-clamp technique and freshly isolated smooth muscle cells from rat tail artery. In whole-cell experiments, SNP considerably increased the outward current compared with the addition of the bath solution. SNP did not alter the current in the presence of iberiotoxin, the specific blocker of BK channels, during co-application with hydroxocobalamin, an NO-scavenger, and in the presence of Rp-8-Br-PET-cGMPS, the specific PKG-inhibitor. In inside-out patches, the activity of BK channels was increased by SNP, SNAP, and DEA-NO. However, these effects did not differ from the effect of the application of drug-free bath solution. Furthermore, a similar increase in single BK channel activity was induced by Rp-8-Br-PET-cGMPS, Rp-8-Br-PET-cGMPS together with SNP, hydroxocobalamin, and hydroxocobalamin together with SNP or DEA-NO. Finally, the activity of excised BK channels did not change in the absence of any application but was considerably increased by PKG compared with the addition of drug-free bath solution. These results suggest that NO released from NO-donors stimulates the BK current only through activation of PKG.

Electrodeposition of NiCu bimetal on 3D printed electrodes for hydrogen evolution reactions in alkaline media

In this study, hydrogen evolution electrodes are prepared by a 3D printing method using conductive PLA filament. To improve their conductivity and electrochemical performance, Nickel–Copper (NiCu) binary coating is deposited on 3D printed (3DP) electrodes in a solution bath with different volume ratios. Electrodes have been prepared as NixCux, NixCu2x, and NixCu3x according to Ni and Cu volume ratio (Ni–Cu; 10-10, 10–20, and 10–30 mL, respectively). Surface morphologies of the samples are measured using FE-SEM, EDX and XRD techniques. Electrochemical characterizations are investigated by LSV, CV and EIS. According to the results, the current density of NiCu coated 3DP electrodes is higher than the uncoated 3DP electrode. The results show that the resistance values of the electrodes are decreased from 0.262 kΩ to 0.187 kΩ in NixCu3x electrode. • Electrodes were prepared by 3D printing method using conductive PLA filament. • Different volume ratios of Ni and Cu metals were deposited on the 3DP electrode. • HER activities of 3DP electrodes were investigated in the alkaline medium at 25 °C. • The kinetic performance of NiCu coated 3DP electrodes was improved significantly. • NixCu3x coated 3DP electrode was provided a good kinetic activity for HER.

Buoyancy-Marangoni Fingering of a Miscible Spreading Drop

We experimentally investigate the interfacial instability that emerges when a water droplet is deposited on a bath of glycerol-water solution. Despite the absence of surface tension to stabilize short-wavelength undulations, we observe finite-size fingers that grow and pinch off from the drop. We show that the fingering patterns formed in the experiments resultes from a balance between the outward buoyancy effect and inward Marangoni flow. This induced Marangoni flow inhibits small perturbations and acts as an effective surface tension on the miscible interface of the spreading drop. To characterize the final size and shape of the drop, we perform systematic experiments by varying the drop volume and the glycerol-water volume fraction. In addition, we have developed scaling arguments for the drop’s final radius using key physical forces, and show that the final wavelength is inversely proportional to the Bond number.

Photocatalytic Recovery of Gold from a Non-Cyanide Gold Plating Solution as Au Nanoparticle-Decorated Semiconductors.

In this work, a photocatalytic process was carried out to recover gold (Au) from the simulated non-cyanide plating bath solution. Effects of semiconductor types (TiO2, WO3, Nb2O3, CeO2, and Bi2O3), initial pH of the solution (3–10), and type of complexing agents (Na2S2O3 and Na2SO3) and their concentrations (1–4 mM each) on Au recovery were explored. Among all employed semiconductors, TiO2 exhibited the highest photocatalytic activity to recover Au from the simulated spent plating bath solution both in the absence and presence of complexing agents, in which Au was completely recovered within 15 min at a pH of 6.5. The presence of complexing agents remarkably affected the size of deposited Au on the TiO2 surface, the localized surface plasmon effect (LSPR) behavior, and the valence band (VB) edge position of the obtained Au/TiO2, without a significant change in the textural properties or the band gap energy. The photocatalytic activity of the obtained Au/TiO2 tested via two photocatalytic processes depended on the common reduction mechanism rather than the textural or optical properties. As a result, the Au/TiO2 NPs obtained from the proposed recovery process are recommended for use as a photocatalyst for the reactions occurring at the conduction band rather than at the valence band. Notably, they exhibited good stability after the fifth photocatalytic cycle for Au recovery from the actual cyanide plating bath solution.