Enhanced cutoff energies for direct and rescattered strong-field photoelectron emission of plasmonic nanoparticles.

The efficient generation, accurate detection, and detailed physical tracking of energetic electrons are of applied interest for high harmonics generation, electron-impact spectroscopy, and femtosecond time-resolved scanning tunneling microscopy. We here investigate the generation of photoelectrons (PEs) by exposing plasmonic nanostructures to intense laser pulses in the infrared (IR) spectral regime and analyze the sensitivity of PE spectra to competing elementary interactions for direct and rescattered photoemission pathways. Specifically, we measured and numerically simulated emitted PE momentum distributions from prototypical spherical gold nanoparticles (NPs) with diameters between 5 and 70 nm generated by short laser pulses with peak intensities of 8.

Evaluation of mechanisms of colistin resistance in strains isolated from patients with urinary tract infection in ICU.

Background And Objectives: One of the major causes of urinary tract infections is Currently, few studies investigated the mechanisms of resistance to colistin in Iran. The current study aimed to determine the prevalence of plasmid and chromosome-mediated resistance to colistin in isolates.

Materials And Methods: 177 urine samples were collected from patients with urinary tract infections hospitalized in the intensive care unit (ICU) of hospitals in the city of Qazvin.

Pulse Energy and Pulse Duration Effects in the Ionization and Fragmentation of Iodomethane by Ultraintense Hard X Rays.

The interaction of intense femtosecond x-ray pulses with molecules sensitively depends on the interplay between multiple photoabsorptions, Auger decay, charge rearrangement, and nuclear motion. Here, we report on a combined experimental and theoretical study of the ionization and fragmentation of iodomethane (CH_{3}I) by ultraintense (∼10^{19}  W/cm^{2}) x-ray pulses at 8.3 keV, demonstrating how these dynamics depend on the x-ray pulse energy and duration.

First detection of mobilized colistin resistance gene in isolated from livestock and sewage in Iran.

Currently, few studies have investigated the mechanisms of resistance to colistin in Iran. The aim of this study was to investigate -harbouring dissemination in livestock and sewage in Iran. A total of 115 samples from cows ( = 38), chickens ( = 47) and urban sewage samples ( = 30) were collected.

Phenotypic Identification and Genotypic Characterization of Plasmid-Mediated AmpC β-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolates in Iran.

One of the mechanisms of Klebsiella pneumoniae and Escherichia coli resistance to β-lactam antibiotics is the production of β-lactamase enzymes. Among these are the AmpC β-lactamases, which confer resistance to a class of antibiotics. However, little is known about the AmpC β-lactamases of K.