A Cryo-XPS Study of Triammonium Citrate-KAuCl<Subscript>4</Subscript>-Na<Subscript>2</Subscript>SO<Subscript>3</Subscript> Electroplating Solutions for Pb-Free Solder Packaging

Cyanide-free Au plating baths, containing KAuCl₄, triammonium citrate, and sodium sulfite, have been developed by the authors. The stability of these solutions depends on the order of mixing of the additives. The aim of this study was to employ turbidity measurements and cryogenic x-ray photoelectron spectroscopy (XPS) to identify the role of the additives and the complexes responsible for solution stability or degradation. Electron microscopy was used to characterize any precipitation products generated in the solutions. It was shown that the long-term stability of the solutions is due to the role of citrate and sulfite as complexing agents.     

Substituted imino and amino derivatives of 4-hydroxycoumarins as novel antioxidant,antibacterial and antifungal agents: Synthesis and in vitro assessments

A series of imino and amino derivatives of 4-hydroxycoumarins were synthesised and evaluated for antioxidant potential, through different in vitro models such as (DPPH) free radical-scavenging activity, linoleic acid emulsion model system, reducing power assay and phosphomolybdenum method. Also, antimicrobial activity of obtained coumarins was evaluated against 13 bacteria and eight fungi. All prepared compounds possessed good antioxidant activity and among them a p-nitrophenol derivative with IC₅₀ at 25.9 μM possessed radical-scavenging activity which was comparable to BHT. Observed data for antibacterial activity indicated strong activity of all tested amino derivatives, while imines showed better antifungal properties.     

Reduction‐Sensitive Dextran Nanogels Aimed for Intracellular Delivery of Antigens

Targeting of antigens to dendritic cells (DCs) to induce strong cellular immune response can be established by loading in a nano‐sized carrier and keeping the antigen associated with the particles until they are internalized by DCs. In the present study, a model antigen (ovalbumin, OVA) is immobilized in cationic dextran nanogels via disulfide bonds. These bonds are stable in the extracellular environment but are reduced in the cytosol of DCs due to the presence of glutathione. Reversible immobilization of OVA in the nanogels is demonstrated by the fact that hardly any release of the protein occurred at pH 7 in the absence of glutathione, whereas rapid release of OVA occurs once the nanogels are incubated in buffer with glutathione. Furthermore, these OVA conjugated nanogels show intracellular release of the antigen in DCs and boost the MHC class I antigen presentation, demonstrating the feasibility of this concept for the aimed intracellular antigen delivery.     

Numerical study of n-heptane/benzene separation by thermal diffusion column

In this article,numerical simulations are performed to investigate the performance of the thermal diffusion column for the separation of n-heptane/benzene mixture.The present work tried to optimize column by analyzing significant parameters such as feed flow rate,temperature and cut.In order to obtain the hydrodynamic and temperature and mass distribution inside thermal diffusion column,computational fluid dynamic(CFD) method is applied to solve the Navier-Stocks equations.Numerical simulations are conducted to study the main parameters in both stationary and time-dependent conditions.By using the separation work unit as a function of cut,the optimal cut for maximum SWU occurs within a limited range of 0.47-0.5 for feed rate between 0.5 and 4 g min-1.Our findings reveal that the optimum feed rate in the range of optimum cut is about 1 g min~(-1).In transient study,results show that the best cut for reaching to steady-state condition is θ=0.5.     

The Tunable Porous Structure of Gelatin–Bioglass Nanocomposite Scaffolds for Bone Tissue Engineering Applications: Physicochemical,Mechanical, and In Vitro Properties

Unidirectional freeze‐casting method is used to fabricate gelatin–bioglass nanoparticles (BGNPs) scaffolds. Transmission electron microscopy (TEM) images show that sol–gel prepared BGNPs are distributed throughout the scaffold with diameters of less than 10 nm. Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetric are used to evaluate the physicochemical properties of BGNPs. Scanning electron microscopy (SEM) micrographs present an oriented porous structure and a homogeneous distribution of BGNPs in the gelatin matrix. The lamellar‐type structure indicates an improvement of mechanical strength and absorption capacity of the scaffolds. Increasing the concentration of BGNPs from 0 to 50 wt% have no noticeable effect on pore orientation, but decreases porosity and pore size distribution. Increase in BGNPs content improves the compressive strength. The absorption and biodegradation rate reduces with augmentation in BGNPs concentration. Bioactivity is evaluated through apatite formation after immersion of the nanocomposites in simulated body fluid and is verified by SEM–energy‐dispersive X‐ray spectroscopy (EDS), an element map analysis, X‐ray powder diffractometer, and FTIR spectrum. SEM images and methyl thiazolyl tetrazolium assay confirm the biocompatibility of scaffolds and the supportive behavior of nanocomposites in cellular spreading. The results show that gelatin–(30 wt%)bioglass nanocomposites have incipient physicochemical and biological properties.     

Optical Imaging Approaches to Monitor Static and Dynamic Cell‐on‐Chip Platforms: A Tutorial Review

Miniaturized laboratories on chip platforms play an important role in handling life sciences studies. The platforms may contain static or dynamic biological cells. Examples are a fixed medium of an organ‐on‐a‐chip and individual cells moving in a microfluidic channel, respectively. Due to feasibility of control or investigation and ethical implications of live targets, both static and dynamic cell‐on‐chip platforms promise various applications in biology. To extract necessary information from the experiments, the demand for direct monitoring is rapidly increasing. Among different microscopy methods, optical imaging is a straightforward choice. Considering light interaction with biological agents, imaging signals may be generated as a result of scattering or emission effects from a sample. Thus, optical imaging techniques could be categorized into scattering‐based and emission‐based techniques. In this review, various optical imaging approaches used in monitoring static and dynamic platforms are introduced along with their optical systems, advantages, challenges, and applications. This review may help biologists to find a suitable imaging technique for different cell‐on‐chip studies and might also be useful for the people who are going to develop optical imaging systems in life sciences studies.     

Dorzolamide nanoliposome as a long action ophthalmic delivery system in open angle glaucoma and ocular hypertension patients

Importance: To reduce the frequency of dorzolamide eye drop administration and increasing the duration of action.

Background: This study aims to compare the effect of dorzolamide loaded-nanoliposome with marketed dorzolamide HCl eye drop on intraocular pressure in primary open angle glaucoma and ocular hypertension patients.

Design: A randomized study was conducted in a hospital.

Participants: Twenty patients with primary open angle glaucoma or ocular hypertension (in both eyes) diagnosis were recruited as participants.

Methods: Dorzolamide loaded-nanoliposome was prepared by thin layer hydration method and characterized. Intra ocular pressure were compared between the two groups who received marketed dorzolamide solution or dorzolamide-loaded nanoliposome.

Main outcome measures: The main outcome measures include intraocular pressure initially (day 0) and on days 14 and 28 and adverse effect of dorzolamide-loaded nanoliposome eye drop.

Results: Based on the results of repeated measure, intra ocular pressure was seen to decrease in both the groups. But these reductions in the intervention group (dorzolamide-loaded eye drop) were significantly higher than those in control group (p?Conclusion: This study confirmed safety and long-lasting efficacy of dorzolamide loaded-nanoliposome eye drop. The highly enhanced permeation through the cornea can be attributed to similarity of phospholipid bilayer of liposomes to the biological membrane and their small particle size and positive zeta potential.     

Competitive Separation of Lead,Cadmium, and Nickel from Aqueous Solutions Using Activated Carbon: Response Surface Modeling,Equilibrium, and Thermodynamic Studies

In this study, the competitive separation of lead, cadmium, and nickel ions from aqueous solutions using a commercial activated carbon (AC) has been investigated and optimized using response surface methodology (RSM). The optimal conditions to reach the highest adsorption capacity for these metals were found as follows: initial pH = 6.3, temperature = 56.8°C, and shaking speed = 308 rpm. Under these conditions, the sequence of adsorption capacity toward the metal ions was as follows: Pb (II): 9.44 mg g^?1 > Cd (II): 9.37 mg g^?1 > Ni (II): 4.52 mg g^?1. The effect of shaking speed on the adsorption capacity of AC was higher than the effects of the initial pH and temperature, indicating the more important role of physisorption than chemisorption in the adsorption of these metal ions. This was confirmed by the results of thermodynamic studies. The equilibrium adsorption data were fitted to the Freundlich, Langmuir adsorption isotherm models and the Dubinin–Radushkevich model parameters were evaluated. All the models were tested and all were shown to represent the experimental data satisfactorily. The thermodynamic parameters such as ΔH, ΔS, and ΔG were computed from the experimental data. These values show that the adsorption is endothermic and spontaneous. The positive value of ΔS° indicates increasing of randomness at the solid/liquid interface during the adsorption of metal ions on AC.