Incoherent Transport through Molecules on Silicon in the vicinity of a Dangling Bond

We theoretically study the effect of a localized unpaired dangling bond (DB) on occupied molecular orbital conduction through a styrene molecule bonded to a n++ H:Si(001)-(2x1) surface. For molecules relatively far from the DB, we find good agreement with the reported experiment using a model that accounts for the electrostatic contribution of the DB, provided we include some dephasing due to low lying phonon modes. However, for molecules within 10 angstrom to the DB, we have to include electronic contribution as well along with higher dephasing to explain the transport features.Comment: 9 pages, 5 figure

Planar Chiral [2.2]Paracyclophane-Based Bisoxazoline Ligands and Their Applications in Cu-Mediated N–H Insertion Reaction

New catalysts for important C–N bond formation are highly sought after. In this work, we demonstrate the synthesis and viability of a new class of planar chiral [2.2]paracyclophane-based bisoxazoline (BOX) ligands for the copper-catalyzed N–H insertion of α-diazocarbonyls into anilines. The reaction features a wide substrate scope and moderate to excellent yields, and delivers the valuable products at ambient conditions

A highly stable, Au/Ru heterobimetallic photoredox catalyst with a [2.2]paracyclophane backbone

We report the synthesis and catalytic application of a highly stable distance-defined Au/Ru heterobimetallic complex. [2.2]Paracyclophane serves as a backbone, holding the two metal centers in a spatial orientation and metal-metal fixed distance. The Au/Ru heterobimetallic complex is highly stable, easily accessible and exhibits promising catalytic activity in a visible-light mediated dual Au/Ru Meyer-Schuster rearrangement.Peer reviewe

Evaluation of Selected Performance Properties of Nanoclay-Modified Asphalt Binders

Asphalt binders are often modified with additives such as acid, polymer, or a combination of multiple additives to achieve improved performance to sustain heavy loads and adverse weather conditions. According to some previous researches, nanoclay can be a good alternative of currently practiced Styrene-Butadiene-Styrene (SBS) modification, and the former is expected to reduce the overall cost of the asphalt binder. Three types of nanoclay (Cloisite 10A, 11B, and 15A) were blended with asphalt binders prepared from two different sources (Arabian Crude and Canadian Crude). A blending protocol has been developed to blend nanoclay with the base binders. Mechanical properties including viscosity, rutting parameter have undergone significant changes after the nanoclay modification. It was also observed that nanoclay modified binders offer different moisture susceptibility while bonding with different aggregates; the nanoclay modified asphalt binder exhibits better bonding with gravel than sandstone. Mechanistic properties such as viscosity and rutting parameter are found to be highly correlated with the chemical compositions. Binders from the Canadian crude showed more colloidal stability than binders from the Arabian crude after nanoclay modification

Preparation and Synthetic Applications of [2.2]Paracyclophane Trifluoroborates: An Efficient and Convenient Route to Nucleophilic [2.2]Paracyclophane Cross‐Coupling Building Blocks

We report the synthesis of [2.2]paracyclophane (PCP) trifluoroborate building blocks that can be used for the incorporation of the PCP moiety into a wide range of (hetero)aryl chlorides, bromides and triflates by a Pd(II)/RuPhos mediated Suzuki–Miyaura cross-coupling reaction. The PCP trifluoroborate species are bench stable with extended shelf life and easily accessible on a multigram scale by a two-step synthesis from commercially available PCP. They can be handled conveniently without special precautions, thus overcoming many of the limitations of other PCP cross-coupling reagents. Additionally, a high yielding regioselective monolithiation/borylation protocol for the synthesis of pseudo-para and pseudo-ortho PCP halotrifluoroborates and their subsequent Suzuki-Miyaura cross-coupling are described

Synthesis and characterization of rigid [2.2]paracyclophane-porphyrin conjugates as scaffolds for fixed-distance bimetallic complexes

This work presents a new approach to prepare mono- and disubstituted linear rigid bimetallic [2.2]paracyclophane-porphyrin conjugates via palladium-mediated Stille cross-coupling reaction. The metalated porphyrin moiety can be varied allowing convenient access to modular metal-metal fixed-distance Cu/Zn complexes.Peer reviewe

Venous thromboembolism following hematopoietic stem cell transplantation-a systematic review and meta-analysis

Venous thromboembolism (VTE) is a common complication of hematopoietic stem cell transplantation (HSCT). Graft-versus-host disease (GVHD) is another complication of HSCT that may modify the risk of VTE. Our objective was to explore the incidence of VTE (deep venous thrombosis and pulmonary embolism) following HSCT and to evaluate its association with GVHD. A comprehensive search of Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Scopus was conducted to search for both retrospective and prospective HSCT studies which had reported VTE. Random-effects meta-analysis was used to pool incidence rates. We included 17 studies reporting on allogeneic- and 10 on autologous-HSCT; enrolling 6693 patients; of which 5 were randomized. The overall incidence of VTE after HSCT was 5%(4-7%). Incidence in allogeneic-HSCT was 4%(2-6%) and in autologous-HSCT was 4%(1-15%). Eleven and nine studies reported data on acute and chronic GVHD, respectively. The incidence of VTE in chronic GVHD was 35%(20-54%), whereas in acute GVHD it was 47%(32-62%). Based on the results of this meta-analysis, VTE is a fairly common complication after HSCT, emphasizing the importance of assimilating guidelines for both treatment and prophylaxis in this patient population

Safe distances between groundwater-based water wells and pit latrines at different hydrogeological conditions in the Ganges Atrai floodplains of Bangladesh.

BACKGROUND: Groundwater drawn from shallow tubewells in Bangladesh is often polluted by nearby pit latrines, which are commonly used toilets in rural and sub-urban areas of the country. METHODS: To determine the minimum safe distance of a tubewell from a pit latrine in different hydrogeological conditions of Bangladesh, 20 monitoring wells were installed at three study sites (Manda, Mohanpur and Bagmara) with the vertical and horizontal distances ranging from 18-47 to 2-15 m, respectively. Water samples were collected three times in three seasons and tested for faecal coliforms (FC) and faecal streptococci (FS) as indicators of contamination. Soil samples were analysed for texture, bulk density and hydraulic conductivity following standard procedures. Sediment samples were collected to prepare lithological logs. RESULTS: When the shallow aquifers at one of the three sites (Mohanpur) were overlained by 18-23-m-thick aquitards, the groundwater of the monitoring wells was found contaminated with a lateral and vertical distances of 2 and 31 m, respectively. However, where the aquitard was only 9 m thick, contamination was found up to lateral and vertical distances of 4.5 and 40.5 m, respectively. The soil textures of all the sites were mainly composed of loam and sandy loam. The hydraulic conductivities in the first aquifer at Manda, Mohanpur and Bagmara were 5.2-7.3, 8.2 and 1.4-15.7 m/h, respectively. CONCLUSIONS: The results showed that the safe distance from the tubewell to the pit latrine varied from site to site depending on the horizontal and vertical distances of the tubewell as well as hydrogeological conditions of a particular area

An Experimental Study Of Combinational Logic Circuit Minimization Using Firefly Algorithm

Combinatorial logic circuit minimization is usually done using Karnaugh’s Map or Boolean equation. This paper presents an application of Firefly Algorithm to design combinational logic circuit in which the objective function is to minimize the total number of gates used. Then, the algorithm is benchmarked with other literatures. Result indicates that it able to find optimal solution but further analysis is required for a more complex combinatorial logic circuit minimization

Metal-to-Metal Distance Modulated Au(I)/Ru(II) Cyclophanyl Complexes : Cooperative Effects in Photoredox Catalysis

The modular synthesis of Au(I)/Ru(II) decorated mono- and heterobimetallic complexes with pi-conjugated [2.2]paracyclophane is described. [2.2]Paracyclophane serves as a rigid spacer which holds the metal centers in precise spatial orientations and allows metal-to-metal distance modulation. A broad set of architectural arrangements of pseudo -geminal, -ortho, -meta, and -para substitution patterns were employed. Metal-to-metal distance modulation of Au(I)/Ru(II) heterobimetallic complexes and the innate transannular pi-communication of the cyclophanyl scaffold provides a promising platform for the investigations of structure-activity relationship and cooperative effects. The Au(I)/Ru(II) heterobimetallic cyclophanyl complexes are stable, easily accessible, and exhibit promising catalytic activity in the visible-light promoted arylative Meyer-Schuster rearrangement.Peer reviewe