Phytogenic nanoparticles: synthesis, characterization, and their roles in physiology and biochemistry of plants.

Researchers are swarming to nanotechnology because of its potentially game-changing applications in medicine, pharmaceuticals, and agriculture. This fast-growing, cutting-edge technology is trying different approaches for synthesizing nanoparticles of specific sizes and shapes. Nanoparticles (NPs) have been successfully synthesized using physical and chemical processes; there is an urgent demand to establish environmentally acceptable and sustainable ways for their synthesis. The green approach of nanoparticle synthesis has emerged as a simple, economical, sustainable, and eco-friendly method. In particular, phytoassisted plant extract synthesis is easy, reliable, and expeditious. Diverse phytochemicals present in the extract of various plant organs such as root, leaf, and flower are used as a source of reducing as well as stabilizing agents during production. Green synthesis is based on principles like prevention/minimization of waste, reduction of derivatives/pollution, and the use of safer (or non-toxic) solvent/auxiliaries as well as renewable feedstock. Being free of harsh operating conditions (high temperature and pressure), hazardous chemicals and the addition of external stabilizing or capping agents makes the nanoparticles produced using green synthesis methods particularly desirable. Different metallic nanomaterials are produced using phytoassisted synthesis methods, such as silver, zinc, gold, copper, titanium, magnesium, and silicon. Due to significant differences in physical and chemical properties between nanoparticles and their micro/macro counterparts, their characterization becomes essential. Various microscopic and spectroscopic techniques have been employed for conformational details of nanoparticles, like shape, size, dispersity, homogeneity, surface structure, and inter-particle interactions. UV-visible spectroscopy is used to examine the optical properties of NPs in solution. XRD analysis confirms the purity and phase of NPs and provides information about crystal size and symmetry. AFM, SEM, and TEM are employed for analyzing the morphological structure and particle size of NPs. The nature and kind of functional groups or bioactive compounds that might account for the reduction and stabilization of NPs are detected by FTIR analysis. The elemental composition of synthesized NPs is determined using EDS analysis. Nanoparticles synthesized by green methods have broad applications and serve as antibacterial and antifungal agents. Various metal and metal oxide NPs such as Silver (Ag), copper (Cu), gold (Au), silicon dioxide (SiO2), zinc oxide (ZnO), titanium dioxide (TiO2), copper oxide (CuO), etc. have been proven to have a positive effect on plant growth and development. They play a potentially important role in the germination of seeds, plant growth, flowering, photosynthesis, and plant yield. The present review highlights the pathways of phytosynthesis of nanoparticles, various techniques used for their characterization, and their possible roles in the physiology of plants.

Impact of Solid Materials in the Gap Space between Driving Electrodes in a MEMS Tri-Electrode Electrostatic Actuator.

MEMS electrostatic actuators can suffer from a high control voltage and a limited displacement range, which are made more prevalent by the pull-in effect. This study explores a tri-electrode topology to enable a reduction in the control voltage and explores the effect of various solid materials forming the space between the two underlying stationary electrodes. Employing solid dielectric material simplifies fabrication and can reduce the bottom primary electrode's fixed voltage. Through numerical analysis, different materials were examined to assess their impact. The results indicate that the primary electrode's fixed voltage can be reduced with an increase in the dielectric constant, however, with the consequence of reduced benefit to control voltage reduction. Additionally, charge analysis was conducted to compare the actuator's performance using air as the gap-spacing material versus solid materials, from the perspective of energy conservation. It was found that solid materials result in a higher accumulated charge, reducing the need for a high fixed voltage.

Understanding chemistry with the symmetry-decomposed Voronoi deformation density charge analysis.

The symmetry-decomposed Voronoi deformation density (VDD) charge analysis is an insightful and robust computational tool to aid the understanding of chemical bonding throughout all fields of chemistry. This method quantifies the atomic charge flow associated with chemical-bond formation and enables decomposition of this charge flow into contributions of (1) orbital interaction types, that is, Pauli repulsive or bonding orbital interactions; (2) per irreducible representation (irrep) of any point-group symmetry of interacting closed-shell molecular fragments; and now also (3) interacting open-shell (i.e., radical) molecular fragments. The symmetry-decomposed VDD charge analysis augments the symmetry-decomposed energy decomposition analysis (EDA) so that the charge flow associated with Pauli repulsion and orbital interactions can be quantified both per atom and per irrep, for example, for σ, π, and δ electrons. This provides detailed insights into fundamental aspects of chemical bonding that are not accessible from EDA.

Catalytic Effect of Hydrogen Bond on Oxhydryl Dehydrogenation in Methanol Steam Reforming on Ni(111).

Dehydrogenation of H3COH and H2O are key steps of methanol steam reforming on transition metal surfaces. Oxhydryl dehydrogenation reactions of HxCOH (x = 0-3) and OH on Ni (111) were investigated by DFT calculations with the OptB88-vdW functional. The transition states were searched by the climbing image nudged elastic band method and the dimer method. The activation energies for the dehydrogenation of individual HxCOH* are 68 to 91 kJ/mol, and reduced to 12-17 kJ/mol by neighboring OH*. Bader charge analysis showed the catalysis role of OH* can be attributed to the effect of hydrogen bond (H-bond) in maintaining the charge of oxhydryl H in the reaction path. The mechanism of H-bond catalysis was further demonstrated by the study of OH* and N* assisted dehydrogenation of OH*. Due to the universality of H-bond, the H-bond catalysis shown here, is of broad implication for studies of reaction kinetics.

A quantitative analysis of light-driven charge transfer processes using voronoi partitioning of time dependent DFT-derived electron densities.

An analytical method is presented that provides quantitative insight into light-driven electron density rearrangement using the output of standard time-dependent density functional theory (TD-DFT) computations on molecular compounds. Using final and initial electron densities for photochemical processes, the subtraction of summed electron density in each atom-centered Voronoi polyhedron yields the electronic charge difference, QVECD . This subtractive method can also be used with Bader, Mulliken and Hirshfeld charges. A validation study shows QVECD to have the most consistent performance across basis sets and good conservation of charge between electronic states. Besides vertical transitions, relaxation processes can be investigated as well. Significant electron transfer is computed for isomerization on the excited state energy surface of azobenzene. A number of linear anilinepyridinium donor-bridge-acceptor chromophores was examined using QVECD to unravel the influence of its pi-conjugated bridge on charge separation. Finally, the usefulness of the presented method as a tool in optimizing charge transfer is shown for a homologous series of organometallic pigments. The presented work allows facile calculation of a novel, relevant quantity describing charge transfer processes at the atomic level. © 2017 Wiley Periodicals, Inc.

Combined Experimental and Computational Studies of a Na2 Ni1-x Cux Fe(CN)6 Cathode with Tunable Potential for Aqueous Rechargeable Sodium-Ion Batteries.

Herein, potential-tunable Na2 Ni1-x Cux Fe(CN)6 nanoparticles with three-dimensional frameworks and large interstitial spaces were synthesized as alternative cathode materials for aqueous sodium-ion batteries by controlling the molar ratio of Ni(II) to Cu(II) at ambient temperature. The influence of the value of x on the crystalline structure, lattice parameters, electrochemical properties, and charge transfer of the resultant compound was explored by using powder X-ray diffractometry, density functional theory, cyclic voltammetry, galvanostatic charge-discharge techniques, and Bader charge analysis. Of the various formulations investigated, that with x=0.25 delivered the highest reversible capacity, superior rate capability, and outstanding cycling performance. These attributes are ascribed to its unique face-centered cubic structure for facile sodium-ion insertion/extraction and the strong interactions between Cu and N atoms, which promote structural stability.

High-precision charge analysis in a catalytic nanoparticle by electron holography.

The charge state of supported metal catalysts is the key to understand the elementary processes involved in catalytic reactions. However, high-precision charge analysis of the metal catalysts at the atomic level is experimentally challenging. To address this critical challenge, high-sensitivity electron holography has recently been successfully applied for precisely measuring the elementary charges on individual platinum nanoparticles supported on a titanium dioxide surface. In this review, we introduce the latest advancements in high-precision charge analysis and discuss the mechanisms of charge transfer at the metal-support interface. The development of charge measurements is entering a new era, and charge analyses under conditions closer to practical working environments, such as real-time, real-space, and reactive gas environments, are expected to be realized in the near future.

Selective, rapid extraction of uranium from aqueous solution by porous chitosan-phosphorylated chitosan-amidoxime macroporous resin composite and differential charge calculation.

Herein, a new porous chitosan-phosphorylated chitosan-amidoxime macroporous resin composite (PCAR) was designed and synthesized for the rapid and selective extraction of uranium resources from aqueous solution. This study showed that PCAR exhibited excellent adsorption toward uranium in a pH range of 5-9. The dynamic adsorption process aligned with the quasi-second-order kinetic model and corresponded to the chemical adsorption process. The maximum adsorption capacity was 561.28 mg·g-1 at pH 6 and 308 K. Mechanism analysis showed that the synergistic effect of the amidoxime group (-(NH2)C=N-OH), PO, and -NH2 on the PCAR surface improved the uranium adsorption performance. The differential charge density indicated that the amidoxime and phosphate groups provide lone-pair electrons for the adsorption of UO22+ and their synergistic effect improves the UO22+ adsorption performance of PCAR. The uranium distribution coefficients of PCAR and CAR are 4.6 and 2.4 times those of vanadium, respectively. These results indicate that phosphorylation can ameliorate the disadvantage of competitive vanadium adsorption of the amidoxime adsorbent. In addition, PCAR exhibits good reusability and stable adsorption capacity after five adsorption-desorption cycles. Hence, PCAR has excellent potential for uranium extraction from aqueous solution.

Hole interactions of aerogen oxides with Lewis bases: an insight into σ-hole and lone-pair-hole interactions.

σ-Hole and lone-pair (lp)-hole interactions of aerogen oxides with Lewis bases (LB) were comparatively inspected in terms of quantum mechanics calculations. The ZOn ⋯ LB complexes (where Z = Kr and Xe, n = 1, 2, 3 and 4, and LB = NH3 and NCH) showed favourable negative interaction energies. The complexation features were explained in light of σ-hole and lp-hole interactions within optimum distances lower than the sum of the respective van der Waals radii. The emerging findings outlined that σ-hole interaction energies generally enhanced according to the following order: KrO4 ⋯ < KrO⋯ < KrO3⋯ < KrO2⋯LB and XeO4⋯ < XeO⋯ < XeO2⋯ < XeO3⋯LB complexes with values ranging from -2.23 to -12.84 kcal mol-1. Lp-hole interactions with values up to -5.91 kcal mol-1 were shown. Symmetry-adapted perturbation theory findings revealed the significant contributions of electrostatic forces accounting for 50-65% of the total attractive forces within most of the ZOn⋯LB complexes. The obtained observations would be useful for the understanding of hole interactions, particularly for the aerogen oxides, with application in supramolecular chemistry and crystal engineering.

Unveiling the positive effect of mineral induced natural organic matter (NOM) on catalyst properties and catalytic dechlorination performance: An experiment and DFT study.

Herein, we report the significant effects of natural organic matter contained in natural zeolite (Z-NOM) on the physicochemical characteristics of a Ni/Fe@natural zeolite (NF@NZ) catalyst and its decontamination performance toward the dechlorination of trichloroethylene (TCE). Z-NOM predominantly consists of humic-like substances and has demonstrable utility in the synthesis of bimetallic catalysts. Compared to NF@NZ600C (devoid of Z-NOM), NF@NZ had increased dispersibility and mobility and showed significant enhancement in the catalytic dechlorination of TCE owing to the encapsulation of Ni0/Fe0 nanoparticles by Z-NOM. The results of corrosion experiments, spectroscopic analyses, and H2 production experiments confirmed that Ni0 acted as an efficient cocatalyst with Fe0 to enhance the dechlorination of TCE to ethane, and Z-NOM-capped Ni0 showed improved adsorption of TCE and atomic hydrogen on their reactive sites and oxidation resistance. The density functional theory (DFT) studies have substantiated the improved adsorption of TCE due to the presence of NOM (especially by COOH structure) and the enhanced charge density at the Ni site in the Ni/Fe bimetal alloy for the stronger adsorption of hydrogen atoms that ultimately enhanced the TCE reduction reaction. These findings illustrate the efficiency of NOM containing natural minerals toward the synthesis of bimetallic catalysts for practical applications.

Utility of preoperative labs in posterior spinal fusions for idiopathic scoliosis.

PURPOSE: Review of 216 consecutive idiopathic scoliosis (IS) patients undergoing posterior spinal fusion (PSF) demonstrated 94.9% having abnormal lab values, but only 3.9% were referred for further evaluation. A limited set of preoperative laboratory testing costing $234/patient, and thorough, adjunct review of patient/family history could identify potentially significant comorbidities preoperatively in this study. A savings of $1556/patient from current laboratory testing was identified. METHODS: The laboratory tests routinely obtained preoperatively were investigated: abnormal preoperative laboratory outcomes were identified and further documented if additional action was taken defined as a referral to another medical provider, performance of additional lab testing or counseling, or if there was alteration of the surgical plan. RESULTS: Overall, 94.9% (n = 205) of patients had one or more abnormal pre-operative lab values. Further actions occurred in 11.7% (n = 24) of all abnormal lab values with 3.9% (n = 8) of these being referred to other healthcare providers. Sixteen abnormal lab values underwent further testing or treatment: 11 nicotine tests, two UCx, one UA, one PT/PTT, and one bovine gelatin RAST. Eight abnormal tests prompted referral to another provider: three CBC, three platelet function tests, one UCx, and one UA. Based on these data, standard preoperative Hgb/Hct, platelet function tests, and bovine RAST (If the surgical plan involves use of bovine gelatin products) appear to be adequate to identify potential significant comorbidities in IS patients undergoing PSF for only $234/patient, a cost savings of $1556/patient from current protocol. CONCLUSION: Based on this study of 216 patients, a limited preoperative laboratory testing and thorough, adjunct review of patient/family history appears to be adequate to identify potential comorbidities preoperatively in this study. LEVEL OF EVIDENCE: II.

Conformational & spectroscopic characterization, charge analysis and molecular docking profiles of chromone-3-carboxylic acid using a quantum hybrid computational method.

The Spectroscopic profile of Chromone-3-Carboxylic Acid (abbreviated as C3CA) was examined using FT-IR, FT-Raman, UV, 1H and 13C NMR techniques. The geometrical parameters and energies attained from DFT/B3LYP method with 6-311++G (d,p) basis sets calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and assigned the fundamental vibrations on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The XRD data obtained from the computed geometric parameters shows that there is little deviation in the structure due to the substitution of the COOH group in the molecule. Using NBO study, the delocalization of the electron and the corresponding attraction between the orbitals shows that the lone pair transition has higher stabilization energy when compared with remaining atoms. The 1H and 13C NMR chemical shifts are calculated using GIAO method and the experimental chemical shifts were analysed with theoretical values which reflects better coincidence. The electronic properties, HOMO and LUMO energies, are performed with TD-DFT reproduces good with the experimental findings. Besides, frontier molecular orbitals (FMO), the high reactive nature of the molecule is identified with MEP and global reactivity descriptor analysis are performed. In addition, the molecular docking study was conducted, and results of the docking study identified the sugar phosphatase inhibitor activity of the target molecule (C3CA).

In-office versus Operating Room Sialendoscopy: Comparison of Outcomes, Patient Time Burden, and Charge Analysis.

OBJECTIVE: To evaluate outcomes of in-office versus operating room (OR) sialendoscopy/sialolithotomy and to recognize the efficiency of outpatient salivary gland surgery with significant time and facility charge reductions. STUDY DESIGN: Case series with chart review. SETTING: State hospital OR and ambulatory clinic. SUBJECTS AND METHODS: Retrospective review was performed of adult patients treated for inflammatory salivary diseases by a single surgeon from 2011 to 2016. The patients were divided into 2 groups based on procedure setting (office vs OR) and compared by various baseline features, including demographics, symptom onset and duration, stone size, symptomatic improvement, and recurrence. Patient time burden was compared via office procedure records and OR time charting from the electronic health record. Retrospective clinic and hospital charge sheets were tallied and similarly compared. RESULTS: The 2 cohorts (office, n = 111; OR, n = 96) were comparable in all demographics, including sialolith number and size (7.36 vs 6.69 mm, P = .45). Additional subgrouping was statistically similar. Both cohorts had similar postprocedure symptom improvement (97% vs 95.8%, P = .65) and recurrence rates (8.9% vs 14.5%, P = .22) independent of subgroup. Overall time burden for patients was 39 minutes in the office versus 277 minutes in the OR ( P ≤ .0001). Procedure and hospital charge data were tallied and compared (office, $719.21; OR, $13,956.14; P ≤ .0001). CONCLUSION: Bothcohorts were statistically similar in all features. There was significant reduction in patient time burden and health care charges with office-based procedures while maintaining similar symptom improvement and recurrence rates.

Reactivity, vibrational spectroscopy, internal rotation and thermochemical aspects of methylarsine.

The aim of this investigation was to perform a characterization of the spectroscopic and thermodynamic properties of methylarsine (CH3AsH2). Post-Hartree-Fock, 29 DFT methods and eight different composite methodologies were employed in these analyses. A comparison between harmonic and anharmonic frequency accuracies in reproducing the observable frequencies was performed here. In addition, the CH3AsH2→CH2AsH3 isomerization barrier energy was estimated in 100kcalmol-1, whereas the H2-release routes barrier heights were in the 45-107kcalmol-1 range. A rate constant of 10-66s-1 was predicted regarding the isomerization route, while the CH2AsH3 hydrogen elimination mechanism is faster than the methylarsine one. The transition state structure of the CH3AsH2 internal rotational barrier energy varied between 1.0 and 1.4kcalmol-1. For the CH2AsH3 internal rotation the estimated barrier heights varied 0.6-2.5kcalmol-1. The adiabatic ionization energy and the heat of formation each structure was also calculated here.

A Charge Comparison of Audiometric Testing in the Pediatric Population.

OBJECTIVE: To determine the charges associated with performing combined tympanometry and otoacoustic emissions vs a comprehensive audiogram in the pediatric population and to analyze its implications for future practice. STUDY DESIGN: Retrospective charge analysis. SETTING: Tertiary care academic center. SUBJECTS AND METHODS: Analysis was performed on 538 pediatric patients who underwent audiometric hearing testing from May through October 2014. RESULTS: In total, 401 patients had combined tympanometry and otoacoustic emissions testing and 91 patients underwent a comprehensive audiogram, while 46 patients underwent all 3 tests. The technical and professional charges for combined tympanometry and otoacoustic emissions were $139 and $116, respectively, with an overall charge of $255. The technical and professional charges for an audiogram were $124 and $198, respectively, with an overall charge of $322. CONCLUSION: Objective testing with a combination of tympanometry and otoacoustic emissions charges insurers $67 less than an audiogram. Given the questionable reliability of behavioral audiometry in very young children, this is a factor to consider when choosing the appropriate test. With a large number of pediatric auditory hearing tests performed each year, the cost savings within the health care system could be substantial.

In Silico vibrational spectroscopic investigation on antioxidant active Mannich base 1-[anilino (phenyl) methyl] pyrrolidine-2,5-dione.

The antioxidant active Mannich base 1-[anilino (phenyl) methyl] pyrrolidine-2,5-dione (APMPD) have been synthesized and its FT-IR and FT-Raman vibrational spectra were recorded within the region of 4000cm(-1), 50cm(-1) respectively. The molecular geometric parameters of APMPD have been computed using HF and DFT model theories. The energies of APMPD are calculated for all the eight possible conformers using B3LYP method at 6-311++G(d,p) basis set. From the computational results, the M1 conformer was identified as the most stable conformer of APMPD. The stable conformer was compared with experimental crystal geometry, which again fortifies the results of conformer analysis. The fundamental vibrations of the molecule are assigned according to the characteristic region and the literature report. The predicted highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap provide vivid idea on charge transfer behavior of APMPD. The molecular electrostatic potential (MEP) and Mulliken charge analysis indicate the feasible electrophilic and nucleophilic reactive sites on APMPD. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at various temperatures are calculated in gas phase.