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Rationale: Silane derivatives play a crucial role in industrial plasma processes for the fabrication of various electronic devices such as lighting devices, solar cells, and displays. Accurate quantitative data are essential for modeling technological plasmas. This study reports the rate coefficients (k) and activation energies (Ea) for thermal electron attachment to Si2Cl6, Si (CH3)3CHF2, and SiCl (CH3)2Si(CH3)3, which are key parameters for understanding the underlying processes in plasmas. The results obtained for other silane derivatives were also analyzed and discussed. Methods: The measurements were conducted using the pulsed Townsend technique. In this technique, electrons generated by a laser under an electric field travel to the anode, inducing a charge on it. In the presence of a scavenger gas, electrons are captured, leading to a decrease in the rate of charge increase over time. The kinetic parameters were deduced from the shape of the pulse. The G4 method was used to obtain bond dissociation energies (BDEs). Results: This study determined the kinetic parameters for thermal electron attachment to Si2Cl6, Si (CH3)3CHF2, and SiCl (CH3)2Si(CH3)3 for the first time. The rate coefficients at 298 K were found to be 2.17 ± 0.04 × 10−9cm3s−1, 2.01 ± 0.09 × 10−12cm3s−1, and 8.05 ± 0.07 × 10−12cm3s−1, respectively. The corresponding activation energies were determined to be 0.37 ± 0.04 eV, 0.29 ± 0.03 eV, and 0.21 ± 0.01 eV for Si2Cl6, Si (CH3)3CHF2, and SiCl (CH3)2Si(CH3)3, respectively. The experiment was conducted over the temperature range of 298–378 K. Conclusions: The findings of this study provide significant new insights into fundamental parameters such as rate coefficients and activation energies for thermal electron capture by chlorinated and fluorinated silane derivatives. These data contribute to advancing our understanding of thermal electron interactions with chlorosilanes, which can be utilized for controlling important species in the plasmas of various modern technologies. [ABSTRACT FROM AUTHOR]

Electron attachment and corresponding dissociative electron attachment (DEA) to cobalt tricarbonyl nitrosyl (Co(CO)3NO) clusters have been studied by co-expansion with Ar gas into a high vacuum. A monochromatic electron beam was utilized to generate negative ions and the resulting reaction products were identified using mass spectrometry. The ion fragments corresponding to Co(CO)3NO monomers closely resemble results from earlier gas phase experiments and studies conducted on Co(CO)3NO in He nanodroplets. However, contrary to the gas phase or He nanodroplet ion yields, a resonance structure comprising several peaks at energies above ∼4 eV was observed both in the case of molecular clusters [Co(CO)3NO]n− (with n = 1, 2, 3) and clusters comprising DEA fragments. Additionally, the ion yields of numerous other clusters such as ions without nitrosyl ([Co(CO)4]−, [Co2(CO)5]−), clusters consisting of two fragments such as ([Co2(CO)NO]−, [Co2(CO)(NO)2]−, [Co2(CO)2NO]−, [Co2(CO)2(NO)2]−, [Co3(CO)(NO)3]−, [Co3(CO)8(NO)3]−, [Co3(CO)(NO)2]−, [Co3(CO)3(NO)2]−, and [Co3(CO)5(NO)2]−) were recorded. Moreover, N＝O bond dissociation was confirmed with the [Co(CO)2N]−ion and with N- or O-retaining cluster ions, such as [Co2(CO)(NO)N]−, [Co2(CO)2(NO)N]−, [Co3(CO)2(NO)N]−, [Co3(CO)3(NO)N]− and [Co3(CO)(NO)2N]−, or [Co2(CO)2O]−, [Co2(CO)3O]−, [Co3(CO)3O]−, [Co3(CO)4O]−and [Co3(CO)2(NO)O]− respectively. [ABSTRACT FROM AUTHOR]

In spite of having deficits in various areas of social cognition, especially in mindreading, Machiavellian individuals are typically very successful in different tasks, including solving social dilemmas. We assume that a profound examination of neural structures associated with decision-making processes is needed to learn more about Machiavellians' abilities in exploiting other people. More specifically, we predicted that high-Mach people would show elevated activity in the brain areas involved in reward-seeking, anticipation of risky situations, and inference making. To test this hypothesis, we used an fMRI technique to examine individuals as they played the Trust Game. In accordance with our predictions, we found consistent activation in high-Machs' thalamus and anterior cingulate cortex (player 1), and dorsal anterior insula/inferior frontal gyrus (player 2). We suggest that Machiavellians conduct specific neural operations in social dilemma situations that make them successful in exploiting others. Machiavellians may have cognitive heuristics that enable them to make predictions about the future reward in a basically risky and unpredictable situation. (Contains 1 table and 6 figures.)

The electron attachment and dissociative electron attachment to gas phase octafluorocyclobutane (c-C4F8) and to its clusters have been measured. The majority of the gas phase products were already reported earlier and have been successfully confirmed in this work. In addition, two new fragments c-C4F7− and C2F5− have been detected at electron energies ∼3.6 eV and 3.1 eV respectively. The parent molecular ion c-C4F8− has been detected not only at the expected ∼0 eV energy, but also with a weak resonance at ∼0.66 eV as well. Contrary to gas phase measurements, the electron attachment to c-C4F8 molecular clusters has been measured for the first time. The dominant ionic products at electron energies ∼0 eV are the monomer, dimer and trimer of ((c-C4F8)n=0,1,2·c-C4F8)−, ((c-C4F8)n=0,1,2·c-C4F7)− and ((c-C4F8)n=0,1,2·F)−. The higher energy resonances at ∼4 eV have been associated with the metastable c-C4F8− ion as well as with possible electron scavenging processes in clusters. Finally, above 8 eV the core-excited electron attachment has been observed. [ABSTRACT FROM AUTHOR]

Experimental investigation of electron ionization (EI) of and electron attachment (EA) onto dicyclohexyl phthalate (DCHP) was carried out using a crossed electron and molecular beam technique. Formation of positive and negative ions by EI and EA with the corresponding dissociation processes was studied and discussed. Due to a low ion yield of the parent positive ion, we were not able to estimate the ionization energy of DCHP. However, we estimated the appearance energies for the protonated phthalate anhydride (m/z 149) to be 10.5 eV and other significant ionic fragments of m/z 249 [DCHP—(R—2H)]+, m/z 167 [DCHP—(2R—3H)]+, and m/z 83 [C6H11]+. The reaction mechanisms of the dissociative ionization process were discussed. In the case of negative ions, we estimated the relative cross sections for a transient negative ion (TNI) and for several detected ions. At low electron energies (close to 0 eV), the TNI of DCHP molecules was the dominant ion, with products of dissociative EA dominating in broad resonances at 7.5 and 8.5 eV. [ABSTRACT FROM AUTHOR]

Genes encoding the tail proteins of the temperate phage 16-3 of the symbiotic nitrogen-fixing bacterium Sinorhizobium meliloti 41 have been identified. First, a new host range gene, designated hII, was localized by using missense mutations. The corresponding protein was shown to be identical to the 85-kDa tail protein by determining its N-terminal sequence. Electron microscopic analysis showed that phage 16-3 possesses an icosahedral head and a long, noncontractile tail characteristic of the Siphoviridae. By using a lysogenic S. meliloti 41 strain, mutants with insertions in the putative tail region of the genome were constructed and virion morphology was examined after induction of the lytic cycle. Insertions in ORF017, ORF018a, ORF020, ORF021, the previously described h gene, and hII resulted in uninfectious head particles lacking tail structures, suggesting that the majority of the genes in this region are essential for tail formation. By using different bacterial mutants, it was also shown that not only the RkpM and RkpY proteins but also the RkpZ protein of the host takes part in the formation of the phage receptor. Results for the host range phage mutants and the receptor mutant bacteria suggest that the HII tail protein interacts with the capsular polysaccharide of the host and that the tail protein encoded by the original h gene recognizes a proteinaceous receptor. doi: 10.1128/JB.01335-09

The C repressor protein of phage 16-3, which is required for establishing and maintaining lysogeny, recognizes structurally different operators which differ by 2 bp in the length of the spacer between the conserved palindromic sequences. A 'rotationally flexible protein homodimers' model has been proposed in order to explain the conformational adaptivity of the 16-3 repressor. In this paper, we report on the isolation of a repressor mutant with altered binding specificity which was used to identify a residue-base pair contact and to monitor the spatial relationship of the recognition helix of C repressor to the contacting major groove of DNA within the two kinds of repressor-operator complexes. Our results indicate spatial differences at the interface which may reflect different docking arrangements in recognition of the structurally different operators by the 16-3 repressor.

Cohesive ends of 16-3, a temperate phage of Rhizobium meliloti 41, have been identified as 10-base-long, 3'-protruding complementary G/C-rich sequences, terS and terL encode the two subunits of 16-3 terminase. Significant homologies were detected among the terminase subunits of phage 16-3 and other phages from various ecosystems.

16-3 is a temperate phage of the symbiotic nitrogen-fixing bacterium Rhizobium meliloti 41. Its prophage state and immunity against superinfection by homoimmune phages are governed by a complex set of controls: the immC and immX repressor systems and the avirT element are all located in well-separated, distinct regions which span 25 kb on the bacteriophage chromosome. The anatomy and function of the immC region are well documented; however, fewer analyses have addressed the immX and avirT regions. We focused in this paper on the immX region and dissected it into two major parts: [X.sub.U/L] and [X.sub.V]. The [X.sub.U/L] part (0.6 kb) contained two overlapping cistrons, [X.sub.U] and [X.sub.L], coding for proteins pXU and pXL, respectively. Inactivation of either gene inactivated the repressor function of the immX region. Loss-of-function mutants of [X.sub.U] and [X.sub.L] complemented each other in trans in double lysogens. The [X.sub.V] part (1 kb) contained a target for [X.sub.U/L] repressor action. Mutations at three sites in [X.sub.V] led to various degree of ImmX insensitivity in a hierarchic manner. Two sites ([X.sub.V1] and [X.sub.V3]) exhibited the inverted-repeat structures characteristic of many repressor binding sites. However, [X.sub.V1] could also be folded into a transcription terminator. Of the two immunity regions of 16-3, immX seems to be unique both in its complex genetic anatomy and in its sequence. To date, no DNA or peptide sequence homologous to that of ImmX has been found in the data banks. In contrast, immC shares properties of a number of immunity systems commonly found in temperate phages.

A plasmid containing Rhizobium meliloti 41 phage 16-3 integrative element of 23-basepair integrates into the chromosomes of R. meliloti 1021 and other bacteria. Sequence data indicate that the target sites of integration is within proline tRNA (CGG) genes.

Phage 16-3 is a temperate phage of Rhizobium meliloti 41 which integrates its genome with high efficiency into the host chromosome by site-specific recombination through DNA sequences of attB and attP. Two phage-encoded genes needed for recombinations at sites int and xis were identified. The findings indicated that phage 16-3 belongs to the integrase family of tyrosine recombinases. The use of the 16-3 site recombination system in biotechnology was examined.

Dissociative electron attachment (DEA) to gas phase leucine (Leu) and isoleucine (Ile) molecules was studied using experimental and quantum-chemical methods. The relative partial cross sections for DEA have been measured using crossed electron/molecular beams technique. Supporting ab initio calculations of the structure, energies of neutral molecules, fragments, and negative ions have been carried out at G3MP2 and B3LYP levels in order to interpret the experimental data. Leu and Ile exhibit several common features. The negative ionic fragments from both molecules are formed in the electron energy range from 0 to approximately 14 eV via three resonances (1.2, 5.5, and 8 eV). The relative partial cross sections for DEA Leu and Ile are very similar. The dominant negative ions formed were closed shell negative ions (M-H)- (m/z=130) formed preferentially via low electron energy resonance of 1.23 eV. Additional negative ions with m/z=115, 114, 113, 112, 84, 82, 74, 45, 26, and 17 have been detected. [ABSTRACT FROM AUTHOR]

Using a crossed electron/molecule beam technique the dissociative electron attachment (DEA) to gas phase L-valine, (CH3)2CHCH(NH2)COOH, is studied by means of mass spectrometric detection of the product anions. Additionally, ab initio calculations of the structures and energies of the anions and neutral fragments have been carried out at G2MP2 and B3LYP levels. Valine and the previously studied aliphatic amino acids glycine and alanine exhibit several common features due to the fact that at low electron energies the formation of the precursor ion can be characterized by occupation of the π* orbital of the carboxyl group. The dominant negative ion (M–H)- (m/Z=116) is observed at electron energies of 1.12 eV. This ion is the dominant reaction product at electron energies below 5 eV. Additional fragment ions with m/Z=100, 72, 56, 45, 26, and 17 are observed both through the low lying π* and through higher lying resonances at about 5.5 and 8.0–9.0 eV, which are characterized as core excited resonances. According to the threshold energies calculated here, rearrangements play a significant role in the formation of DEA fragments observed from valine at subexcitation energies. [ABSTRACT FROM AUTHOR]

Examines the role of specific complexes formed by RepA protein in replication initiation of plasmid pCU1. Analysis of specific complexes formed by Rep A; Prediction of a RepA binding site; Determination of bases relevant to RepA binding by missing-nucleoside method; Participation of thymine 5-methyl groups in RepA binding.

Examines the integrative elements of rhizobiophage 16-3 into proline tRNA. Classification of integrase protein of rhizobium meliloti; Details on the site-specific recombination system of the phage; Importance of site-specific integration in introducing genetic information.

Electron attachment and corresponding dissociative electron attachment (DEA) to cobalt tricarbonyl nitrosyl (Co(CO) 3 NO) clusters have been studied by co-expansion with Ar gas into a high vacuum. A monochromatic electron beam was utilized to generate negative ions and the resulting reaction products were identified using mass spectrometry. The ion fragments corresponding to Co(CO) 3 NO monomers closely resemble results from earlier gas phase experiments and studies conducted on Co(CO) 3 NO in He nanodroplets. However, contrary to the gas phase or He nanodroplet ion yields, a resonance structure comprising several peaks at energies above ∼4 eV was observed both in the case of molecular clusters [Co(CO) 3 NO] n - (with n = 1, 2, 3) and clusters comprising DEA fragments. Additionally, the ion yields of numerous other clusters such as ions without nitrosyl ([Co(CO) 4 ] - , [Co 2 (CO) 5 ] - ), clusters consisting of two fragments such as ([Co 2 (CO)NO] - , [Co 2 (CO)(NO) 2 ] - , [Co 2 (CO) 2 NO] - , [Co 2 (CO) 2 (NO) 2 ] - , [Co 3 (CO)(NO) 3 ] - , [Co 3 (CO) 8 (NO) 3 ] - , [Co 3 (CO)(NO) 2 ] - , [Co 3 (CO) 3 (NO) 2 ] - , and [Co 3 (CO) 5 (NO) 2 ] - ) were recorded. Moreover, NO bond dissociation was confirmed with the [Co(CO) 2 N] - ion and with N- or O-retaining cluster ions, such as [Co 2 (CO)(NO)N] - , [Co 2 (CO) 2 (NO)N] - , [Co 3 (CO) 2 (NO)N] - , [Co 3 (CO) 3 (NO)N] - and [Co 3 (CO)(NO) 2 N] - , or [Co 2 (CO) 2 O] - , [Co 2 (CO) 3 O] - , [Co 3 (CO) 3 O] - , [Co 3 (CO) 4 O] - and [Co 3 (CO) 2 (NO)O] - respectively.

In this work, we probe anion production upon electron interaction with Fe(CO) 5 clusters using two complementary cluster-beam setups. We have identified two mechanisms that lead to synthesis of complex anions with mixed Fe/CO composition. These two mechanisms are operative in distinct electron energy ranges. It is shown that the elementary decomposition mechanism that has received perhaps the most attention in recent years (i.e., dissociative electron attachment at energies close to 0 eV) becomes suppressed upon increasing aggregation of iron pentacarbonyl. We attribute this suppression to the electrostatic shielding of a long-range interaction that strongly enhances the dissociative electron attachment in isolated Fe(CO) 5 .