Orientation-dependent ionization yields from strong-field ionization of fixed-in-space linear and asymmetric top molecules

The yield of strong-field ionization, by a linearly polarized probe pulse, is studied experimentally and theoretically, as a function of the relative orientation between the laser field and the molecule. Experimentally, carbonyl sulfide, benzonitrile and naphthalene molecules are aligned in one or three dimensions before being singly ionized by a 30 fs laser pulse centered at 800 nm. Theoretically, we address the behaviour of these three molecules. We consider the degree of alignment and orientation and model the angular dependence of the total ionization yield by molecular tunneling theory accounting for the Stark shift of the energy level of the ionizing orbital. For naphthalene and benzonitrile the orientational dependence of the ionization yield agrees well with the calculated results, in particular the observation that ionization is maximized when the probe laser is polarized along the most polarizable axis. For OCS the observation of maximum ionization yield when the probe is perpendicular to the internuclear axis contrasts the theoretical results.Comment: 14 pages, 4 figure

At The Five And Ten Cent Store

https://digitalcommons.library.umaine.edu/mmb-vp/4681/thumbnail.jp

Nonequilibrium Green function approach to photoionization processes in atoms

We present a quantum kinetic approach for the time-resolved description of many-body effects in photoionization processes in atoms. The method is based on the non-equilibrium Green functions formalism and solves the Keldysh/Kadanoff-Baym equations in second Born approximation. An approximation scheme is introduced and discussed, which provides a complete single-particle description of the continuum, while the atom is treated fully correlated.Comment: 11 pages, 6 figure

Towards the use of (pseudo) nucleobase substituted amphiphiles as DNA nucleotide mimics and antimicrobial agents

Here we present the synthesis of complementary (pseudo) nucleobase appended Supramolecular Self-associating Amphiphilic (SSA) salts and, establish the potential for this molecular construct to produce a new class of DNA inspired synthetic structures/materials. The anionic component of this class of amphiphile contains multiple hydrogen bond donating and accepting functionalities, meaning that these systems can access multiple self-associative hydrogen bonding modes simultaneously. Herein, we characterise the self-associative properties of these DNA inspired amphiphiles in the solid state, solution state and gas phase. Finally, we investigate the potential of these amphiphilic salts to act as antimicrobial agents against model Gram-positive (methicillin resistant Staphylococcus aureus – MRSA) and Gram-negative (Escherichia coli – E. coli) bacteria

Identification of organophosphorus simulants for the development of next-generation detection technologies

Organophosphorus (OP) chemical warfare agents (CWAs) represent an ongoing threat but the understandable widespread prohibition of their use places limitations on the development of technologies to counter the effects of any OP CWA release. Herein, we describe new, accessible methods for the identification of appropriate molecular simulants to mimic the hydrogen bond accepting capacity of the P[double bond, length as m-dash]O moiety, common to every member of this class of CWAs. Using the predictive methodologies developed herein, we have identified OP CWA hydrogen bond acceptor simulants for soman and sarin. It is hoped that the effective use of these physical property specific simulants will aid future countermeasure developments

Badania porównawcze właściwości przędz Vortex i obrączkowych oraz właściwości tkanin zawierających te przędze w wątku

The purpose of the research was to examine the properties of vortex and ring spun yarns and their influence on the properties of woven fabrics when used as weft. Two different mixtures of fibres (Cotton/PET; Cotton/PA6.6) in different portions and pure cellulose viscose (CV) fibres from the same input material were used to produce vortex and ring spun yarn of 16 & 67 tex. The properties of the measured yarns evaluated showed that ring spun yarns were, depending on the blend used, superior in the breaking force up to 30% and in the elongation at break up to 20%. The same occurred with the properties of woven fabrics in the weft direction, only that the difference was significantly smaller – up to 15% breaking force and up to 5% elongation at break. At the same time the abrasion properties of woven fabrics containing vortex yarns in the weft were significantly better than those of full ring spun yarn fabrics.Wybrano dwie różne mieszanki włókien (bawełna PET i PA6.6) w różnych proporcjach, jak również jednorodne włókna celulozowe typu Modal. Wyprodukowano przędze Vortex i obrączkowe o masie liniowej 16 tex i 67 tex. Badania właściwości wyprodukowanych włókien wykazały, że przędze obrączkowe miały lepsze właściwości wytrzymałościowe zależne od składu procentowego mieszanki. Wytrzymałość przędz różniła się o 30%, podczas gdy wydłużenie przy zerwaniu różniło się o 20%. Podobne zależności stwierdzono badając wytrzymałość tkanin w kierunku wątku, z tym, że różnice były tu znacznie mniejsze, do 15% jeżeli chodzi o wytrzymałość, a do 5% wydłużenie przy zerwaniu. Jednocześnie stwierdzono, że odporność na ścieranie była znacznie lepsza dla tkanin wykonanych z przędzy Vortex w wątku

Ehogenicity of thyroid gland on ultrasonography in primary hypothyroidism

Background. The aim of this study was to investigate the association between echogenicity of thyroid gland and low thyroid function. Methods. The study group included 60 patients, with normal and low thyroid function, who visited the Outpatient Department of the Clinic of Endocrinology, Diabetes and Metabolic Disorders in the period from April 2008 to October 2009. Echogenicity of the thyroid gland in all patients was evaluated by ultrasonography as well as serum concentrations of TSH, fT4 and thyroid autoantibody (anti-TPO). To find out the association between thyroid ehogenicity with mean TSH and anti-TPO in different ages, we divided the patients into five subgroups according to age. Results. Patients with decreased echogenicity had a higher mean TSH compared with patients with normal echogenicity (2.77 mIU/l vs. 1.75 mIU/l) (p=0.04). Differences were more significant in patients with markedly decreased echogenicity (6.34 mIU/l vs. 1.75 mIU/l) (p< 0.0001). Patients with reduced echogenicity had a higher risk of having anti-TPO than patients without normal echogenicity (p<0.001). This association was stronger when echogenicity was markedly decreased. According to age, only younger population (19-29 years) with decreeased and markedly decreased echogenicity had significantly higher mean TSH and anti-TPO values. Conclusions. Thyroid ultrasonography changes can be used as an early sign of low thyroid function, especially in younger population