Phase transitions during formation of Ag nanoparticles on In2S3 precursor layers

Phase transitions have been investigated for silver deposition onto In2S3 precursor layers by spray chemical vapor deposition from a trimethylphosphine (hexafluoroacetylacetonato) silver (Ag(hfacac)(PMe3)) solution. The formation of Ag nanoparticles (Ag NPs) on top of the semiconductor layer set on concomitant with the formation of AgIn5S8. The increase of the diameter of Ag NPs was accompanied by the evolution of orthorhombic AgInS2. The formation of Ag2S at the interface between Ag NPs and the semiconductor layer was observed. Surface photovoltage spectroscopy indicated charge separation and electronic transitions in the ranges of corresponding band gaps. The phase transition approach is aimed to be applied for the formation of plasmonic nanostructures on top of extremely thin semiconducting layers

Path integral solution for an angle-dependent anharmonic oscillator

We have given a straightforward method to solve the problem of noncentral anharmonic oscillator in three dimensions. The relative propagator is presented by means of path integrals in spherical coordinates. By making an adequate change of time we were able to separate the angular motion from the radial one. The relative propagator is then exactly calculated. The energy spectrum and the corresponding wave functions are obtained.Comment: Corrected typos and mistakes, To appear in Communications in Theoretical Physic

A randomized multi-center phase II trial of the angiogenesis inhibitor Cilengitide (EMD 121974) and gemcitabine compared with gemcitabine alone in advanced unresectable pancreatic cancer

BACKGROUND: Anti-angiogenic treatment is believed to have at least cystostatic effects in highly vascularized tumours like pancreatic cancer. In this study, the treatment effects of the angiogenesis inhibitor Cilengitide and gemcitabine were compared with gemcitabine alone in patients with advanced unresectable pancreatic cancer. METHODS: A multi-national, open-label, controlled, randomized, parallel-group, phase II pilot study was conducted in 20 centers in 7 countries. Cilengitide was administered at 600 mg/m(2 )twice weekly for 4 weeks per cycle and gemcitabine at 1000 mg/m(2 )for 3 weeks followed by a week of rest per cycle. The planned treatment period was 6 four-week cycles. The primary endpoint of the study was overall survival and the secondary endpoints were progression-free survival (PFS), response rate, quality of life (QoL), effects on biological markers of disease (CA 19.9) and angiogenesis (vascular endothelial growth factor and basic fibroblast growth factor), and safety. An ancillary study investigated the pharmacokinetics of both drugs in a subset of patients. RESULTS: Eighty-nine patients were randomized. The median overall survival was 6.7 months for Cilengitide and gemcitabine and 7.7 months for gemcitabine alone. The median PFS times were 3.6 months and 3.8 months, respectively. The overall response rates were 17% and 14%, and the tumor growth control rates were 54% and 56%, respectively. Changes in the levels of CA 19.9 went in line with the clinical course of the disease, but no apparent relationships were seen with the biological markers of angiogenesis. QoL and safety evaluations were comparable between treatment groups. Pharmacokinetic studies showed no influence of gemcitabine on the pharmacokinetic parameters of Cilengitide and vice versa. CONCLUSION: There were no clinically important differences observed regarding efficacy, safety and QoL between the groups. The observations lay in the range of other clinical studies in this setting. The combination regimen was well tolerated with no adverse effects on the safety, tolerability and pharmacokinetics of either agent

Antimicrobial and Osseointegration Properties of Nanostructured Titanium Orthopaedic Implants

The surface design of titanium implants influences not only the local biological reactions but also affects at least the clinical result in orthopaedic application. During the last decades, strong efforts have been made to improve osteointegration and prevent bacterial adhesion to these surfaces. Following the rule of “smaller, faster, cheaper”, nanotechnology has encountered clinical application. It is evident that the hierarchical implant surface micro- and nanotopography orchestrate the biological cascades of early peri-implant endosseous healing or implant loosening. This review of the literature gives a brief overview of nanostructured titanium-base biomaterials designed to improve osteointegration and prevent from bacterial infection

An access to base-stabilized three-membered silicon heterocycles

Azhakar R, Roesky HW, Ghadwal R, Holstein JJ, Dittrich B. An access to base-stabilized three-membered silicon heterocycles. Dalton Transactions. 2012;41(32): 9601.The three-membered silacyclic ring compounds LSi[N2(Ph)2]tBu (1), LSi[HCN(Ph)2]tBu (2) and LSi[C2(Ph)2]tBu (3) were obtained by the treatment of base stabilized monoalkylsilylenes LSitBu (L = PhC(NtBu)2) with PhN[double bond, length as m-dash]NPh, PhN[double bond, length as m-dash]CHPh and PhC[triple bond, length as m-dash]CPh. The reaction of PhN[double bond, length as m-dash]NPh and PhC[triple bond, length as m-dash]CPh with LSitBu shows a different reactivity pattern with base stabilized monochlorosilylene LSiCl. The arrangement of the three-membered ring (SiNN) in 1 is the first structurally isolated example of a siladiaziridine compound

Neutral Pentacoordinate Silicon Fluorides Derived from Amidinate, Guanidinate, and Triazapentadienate Ligands and Base-Induced Disproportionation of Si Cl to Stable Silylenes

Ghadwal R, Pröpper K, Dittrich B, Jones PG, Roesky HW. Neutral Pentacoordinate Silicon Fluorides Derived from Amidinate, Guanidinate, and Triazapentadienate Ligands and Base-Induced Disproportionation of Si Cl to Stable Silylenes. Inorganic Chemistry. 2011;50(1):358-364

A Dimer of Silaisonitrile with Two-Coordinate Silicon Atoms

Ghadwal R, Roesky HW, Pröpper K, Dittrich B, Klein S, Frenking G. A Dimer of Silaisonitrile with Two-Coordinate Silicon Atoms. Angewandte Chemie International Edition. 2011;50(23):5374-5378.A specialty of silicon: A stable dimeric silaisonitrile (ArNSi:)2 (see picture; Ar=2,6-bis(2,4,6-triisopropylphenyl)phenyl) was prepared by the reduction of dichlorosilaimine IPr⋅Cl2Si NAr with KC8. The dimer is the first base-free disilylene with two-coordinate silicon atoms; reaction with trimethylsilyl azide affords the first bis(silaimine) (ArNSi NSiMe3)2 with three-coordinate silicon atoms

N-Heterocyclic Carbene Stabilized Dichlorosilylene Transition-Metal Complexes of V(I), Co(I), and Fe(0)

Ghadwal R, Azhakar R, Pröpper K, Holstein JJ, Dittrich B, Roesky HW. N-Heterocyclic Carbene Stabilized Dichlorosilylene Transition-Metal Complexes of V(I), Co(I), and Fe(0). Inorganic Chemistry. 2011;50(17):8502-8508