3-dimensional electrode patterning within a microfluidic channel using metal ion implantation

The application of electrical fields within a microfluidic channel enables many forms of manipulation necessary for lab-on-a-chip devices. Patterning electrodes inside the microfluidic channel generally requires multi-step optical lithography. Here, we utilize an ion-implantation process to pattern 3D electrodes within a fluidic channel made of polydimethylsiloxane (PDMS). Electrode structuring within the channel is achieved by ion implantation at a 40° angle with a metal shadow mask. The advantages of three-dimensional structuring of electrodes within a fluidic channel over traditional planar electrode designs are discussed. Two possible applications are presented: asymmetric particles can be aligned in any of the three axial dimensions with electro-orientation; colloidal focusing and concentration within a fluidic channel can be achieved through dielectrophoresis. Demonstrations are shown with E. coli, a rod shaped bacteria, and indicate the potential that ion-implanted microfluidic channels have for manipulations in the context of lab-on-a-chip devices

Spectroscopic and quantum mechanical investigations of (2E)-3-(2H-1,3-benzodioxol-5-yl)-N-phenylprop-2-enamide using density functional theory method

The Fourier transform infrared (FTIR) and FT-Raman of (2E)-3-(2H-1,3-benzodioxol-5-yl)-N-phenylprop-2-enamide (2BNP2E) have been recorded in the regions 4000-100 and 4000-450cm-1, respectively. A complete assignment and analysis of the fundamental vibrational modes of the molecule have been carried out. The observed fundamental modes have been compared with the harmonic vibrational frequencies computed using DFT (B3LYP) method by employing 6-311++G(d,p) basis set. The vibrational studies have been interpreted in terms of potential energy distribution. The first order hyperpolarizability (β0) and related properties (α, μ and ∆α) of this molecular system are calculated using B3LYP/6-311++G(d,p) method based on the finite-field approach. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that electron density (ED) in the σ* and π* anti-bonding orbitals and second-order delocalization energies (E(2)) confirm the occurrence of intramolecular charge transfer (ICT) within the molecule. Molecular electrostatic potential (MEP) and HOMO-LUMO energy levels have also been constructed. The thermodynamic properties of the title compound have been calculated at different temperature and the results reveal that the standard heat capacity C, entropy S and enthalpy changes H increase with rise in temperature

Moduli Spaces of Lumps on Real Projective Space

Harmonic maps that minimize the Dirichlet energy in their homotopy classes are known as lumps. Lump solutions on real projective space are explicitly given by rational maps subject to a certain symmetry requirement. This has consequences for the behaviour of lumps and their symmetries. An interesting feature is that the moduli space of charge three lumps is a D2-symmetric 7-dimensional manifold of cohomogeneity one. In this paper, we discuss the charge three moduli spaces of lumps from two perspectives: discrete symmetries of lumps and the Riemann-Hurwitz formula. We then calculate the metric and find explicit formula for various geometric quantities. We also discuss the implications for lump decay

Toward understanding the S2-S3 transition in the Kok cycle of Photosystem II:Lessons from Sr-substituted structure

Understanding the water oxidation mechanism in Photosystem II (PSII) stimulates the design of biomimetic artificial systems that can convert solar energy into hydrogen fuel efficiently. The Sr2+-substituted PSII is active but slower than with the native Ca2+ containing PSII as an oxygen evolving catalyst. Here, we use Density Functional Theory (DFT) to compare the energetics of the S2 to S3 transition in the Mn4O5Ca2+ and Mn4O5Sr2+ clusters. The calculations show that deprotonation of the water bound to Ca2+ (W3), required for the S2 to S3 transition, is energetically more favorable in Mn4O5Ca2+ than Mn4O5Sr2+. In addition, we have calculated the pKa of the water that bridges Mn4 and the Ca2+/Sr2+ in the S2 state using continuum electrostatics. The calculations show that the pKa is higher by 4 pH units in the Mn4O5Sr2+cluster

Tuning parameters of metal ion implantation within a microfluidic channel

Applying electrical fields is a simple and versatile method to manipulate and reconfigure optofluidic devices. Several methods to apply electric fields using electrodes on polymers or in the context of lab-on-a-chip devices exist. In this paper, we utilize an ion-implanted process to pattern electrodes within a fluidic channel made of polydimethylsiloxane (PDMS). Electrode structuring within the channel is achieved by ion implantation at a 40° angle with a metal shadow mask. In previous work using the ion-implantation process, we demonstrated two possible applications in the context of lab-on-a-chip applications. Asymmetric particles were aligned through electro-orientation. Colloidal focusing and concentration was possible with negative dielectrophoresis. In this paper, we discuss the different electrode structures that are possible by changing the channel dimensions. A second parameter of ion implantation dosage prevents the shorting of electrodes on the side wall or top wall of the fluidic channel to the bottom. This allows for floating electrodes on the side wall or top wall. These type of electrodes help prevent electrolysis as the liquid is not in direct contact with the voltage source. Possible applications of the different electrode structures that are possible are discussed

A Comparative Study of Efficacy and Safety among Metformin, Sitagliptin, and Glimepiride Monotherapies in Patients with Type 2 Diabetes Mellitus

Effective management of type 2 diabetes mellitus (T2DM) requires lifestyle changes and suitable medications to enhance quality of life and prevent complications. Choosing the right treatment involves considering the patient's clinical profile, drug efficacy, side effects, and cost. This study compares the safety and efficacy of sitagliptin, glimepiride, and metformin in T2DM patients. A prospective cross-sectional study was conducted at the Diabetes Center of Layla Qasim, Erbil, Iraq, including 143 diabetic patients. They were divided into three groups: group A received glimepiride (N=50), group B metformin (N=48), and group C sitagliptin (N=45). Drug costs, therapeutic outcomes, and side effects were analyzed. Patients aged 30 to 78 participated, with a female-to-male ratio of 83:60. All groups showed significantly improved HbA1c levels (P=0.001). Total cholesterol (TC) and LDL levels were also significantly different (P=0.047 and P=0.010, respectively). Sitagliptin significantly increased triglycerides (TG) and HDL-C. Gastrointestinal side effects were prominent in the metformin group. When selecting medication for T2DM, factors like age, HbA1c, glucose levels, obesity, metabolic syndrome, insulin secretion, and hypoglycemia risk should be considered. Both sitagliptin and glimepiride were well tolerated, with minimal hypoglycemia risk and no significant weight differences between groups. Glimepiride is an effective, safe, and weight-neutral adjunct to metformin, offering extrapancreatic benefits and remains a viable second-line treatment option for T2DM patients

Probing the Water Stability Limits and Degradation Pathways of Metal-Organic Frameworks (MOFs)

A comprehensive model to describe the water stability of prototypical metal–organic frameworks (MOFs) is derived by combining different types of theoretical and experimental approaches. The results provide an insight into the early stages of water-triggered destabilization of MOFs and allow detailed pathways to be proposed for the degradation of different MOFs under aqueous conditions. The essential elements of the approach are computing the pKa values of coordinated water molecules and geometry relaxations. Variable-temperature and pH infrared spectroscopy techniques are used to corroborate the main findings. The model developed herein helps to explain stability limits observed for several prototypical MOFs, including MOF-5, HKUST-1, UiO-66, and MIL-101-Cr, in aqueous solutions, and thus, provides an insight into the possible degradation pathways in acidic and basic environments. The formation of a metal hydroxide through the autoprotolysis of metal-coordinated water molecules and the strength of carboxylate–metal interactions are suggested to be two key players that govern stability in basic and acidic media, respectively. The methodology presented herein can effectively guide future efforts, which are especially significant for in silico screening, for developing novel MOFs with enhanced aqueous stability

Tuning the Chemical Environment within the UiO-66-NH2 Nanocages for Charge-Dependent Contaminant Uptake and Selectivity

The remarkable water stability of Zr-carboxylatebased metal-organic frameworks (MOFs) stimulated considerable interest toward their utilization in aqueous phase applications. The origin of such stability is probed here through pH titration and plc modeling. A unique feature of the Zr-6(mu 3OH)(4)(mu O-3)(4)(RCO2)(12) cluster is the Zr-bridging oxo/hydroxyl groups, demonstrating several pK(a) values that appear to provide for the water stability at a wide range of pH. Accordingly, the tunability of the cage/surface charge of the MOF can feasibly be controlled through careful adjustment of solution pH. Such high stability, and facile control over cage/surface charge, can additionally be augmented through introducing chemical functionalities lining the cages of the MOF, specifically amine groups in the UiO-66-NH2 presented herein. The variable protonation states of the Zr cluster and the pendant amino groups, their H-bond donor/acceptor characteristics, and their electrostatic interactions with guest molecules were effectively utilized in controlled experiments to demonstrate high uptake of model guest molecules (137 mg/g for Cr(VI), 1275 mg/g for methylene blue, and 909 mg/g for methyl orange). Additionally, a practical form of the silica-supported MOF, UiO-66-NH2 @SiO2, constructed in under 2 h reaction time, is described, generating a true platform microporous sorbent for practical use in demanding applications

Mechanical properties of electroactive polymer microactuators with ion-implanted electrodes

Mosquées et centres islamiques : vers l’expansion L’établissement de mosquées et de centres islamiques aux États-Unis remonte au début du xxe siècle. La mosquée la plus ancienne – encore en place aujourd’hui mais transformée en site historique – fut bâtie par des Arabes en 1934 dans l’Iowa. Par la suite, un certain nombre de mosquées et de centres islamiques virent le jour sur l’ensemble du territoire américain. À partir des années 1960 et 1970, durant lesquelles des immigrants qualifiés, sud..

Effect of benzoyl treatment on the performance of sugar palm/kenaf fiber-reinforced polypropylene hybrid composites

The main purpose of this work is to investigate the effect of benzoyl treatment on the performance of sugar palm/kenaf fiber-reinforced polypropylene hybrid composites. Water absorption tests were carried out to confirm the effect of benzoylation treatment toward fabricating a more hydrophobic behavior of the hybrid composites. Both treated and untreated composites that have 10 wt.% of fiber loading with three different fiber ratios between sugar palm and kenaf (7:3, 5:5, 3:7) were analyzed. Physical and mechanical properties such as tensile, flexural, and impact strength were determined from this study. Morphological properties were obtained using scanning electron microscopy (SEM). It was found that the tensile strength of sugar palm/kenaf-reinforced polypropylene hybrid composites was improved with the treatment of benzoyl with a value of 19.41 MPa. In addition, hybrid composite with treated sugar palm and kenaf fiber T-SP3K7 recorded the highest impact and flexural strength of 19.4 MPa and 18.4 MPa, respectively. In addition, SEM demonstrated that surface treatment enhanced the mechanical properties of the hybrid composites. Overall, it can be suggested that benzoyl-treated composites with a higher volume of kenaf fiber than sugar palm fiber will improve the mechanical characteristics of the hybrid composites