Photoemission studies of the near Fermi level spectral weight shifts in FeSe1-xTex superconductor

Our valence band photoelectron spectroscopic studies show a temperature dependent spectral weight transfer near the Fermi level in the Fe-based superconductor FeSe1-xTex. Using theoretical band structure calculations we have shown that the weight transfer is due to the temperature induced changes in the Fe(Se,Te)4 tetrahedra. These structural changes lead to shifts in the electron occupancy from the xz/yz and x2-y2 orbitals to the 3z2-r2 orbitals indicating a temperature induced crossover from a metallic state to an Orbital Selective Mott (OSM) Phase. Our study presents the observation of a temperature induced crossover to a low temperature OSM phase in the family of Fe chalcogenides.Comment: 10 pages, 4 figure

Disorder and excess modes in hard-sphere colloidal systems

The anomalous thermodynamic properties of glasses remain incompletely understood, notably the anomalous peak in the heat capacity at low temperatures; it is believed to be due to an excess of low-frequency vibrational modes and a manifestation of the structural disorder in these systems. We study the thermodynamics and vibrational dynamics of colloidal glasses and (defected) crystals. The experimental determination of the vibrational density of states allows us to directly observe a strong enhancement of low-frequency modes. Using a novel method (Zargar R. et al., Phys. Rev. Lett. 110 (2013) 258301) to determine the free energy, we also determine the entropy and the specific heat experimentally. It follows that the emergence of the excess modes and high values of the specific heat are directly related and are specific to the glass: even for solids containing a very large amount of defects, both the low-frequency density of states and the specific heat are significantly smaller than for the glass

Nonequilibrium free energy of colloidal glasses under shear

The free energy of hard-sphere systems provides a direct link between the particle-scale structure and macroscopic thermodynamic properties. Here, we employ this framework to investigate the shear-induced structure of a colloidal glass, and link it to its macroscopic mechanical and thermodynamic state. We measure the nonequilibrium free energy under shear from the free volumes of the particles, and monitor its evolution with the applied strain. Unlike crystals, for which the elastic energy increases quadratically with strain due to affine particle displacements, for glasses the free energy decreases due to non-affine displacements and dissipation, reflecting the ability of the glass to reach deeper free-energy minima. We model this decrease using the nonaffine shear modulus and a standard viscous dissipative term. Our model and measurements allow us to disentangle the complex contributions of affine and nonaffine particle displacements in the transient shear deformation of glasses

<i>In vitro</i> Characterization of Phenylacetate Decarboxylase, a Novel Enzyme Catalyzing Toluene Biosynthesis in an Anaerobic Microbial Community

Anaerobic bacterial biosynthesis of toluene from phenylacetate was reported more than two decades ago, but the biochemistry underlying this novel metabolism has never been elucidated. Here we report results of in vitro characterization studies of a novel phenylacetate decarboxylase from an anaerobic, sewage-derived enrichment culture that quantitatively produces toluene from phenylacetate; complementary metagenomic and metaproteomic analyses are also presented. Among the noteworthy findings is that this enzyme is not the well-characterized clostridial p-hydroxyphenylacetate decarboxylase (CsdBC). However, the toluene synthase under study appears to be able to catalyze both phenylacetate and p-hydroxyphenylacetate decarboxylation. Observations suggesting that phenylacetate and p-hydroxyphenylacetate decarboxylation in complex cell-free extracts were catalyzed by the same enzyme include the following: (i) the specific activity for both substrates was comparable in cell-free extracts, (ii) the two activities displayed identical behavior during chromatographic separation of cell-free extracts, (iii) both activities were irreversibly inactivated upon exposure to O2, and (iv) both activities were similarly inhibited by an amide analog of p-hydroxyphenylacetate. Based upon these and other data, we hypothesize that the toluene synthase reaction involves a glycyl radical decarboxylase. This first-time study of the phenylacetate decarboxylase reaction constitutes an important step in understanding and ultimately harnessing it for making bio-based toluene

Airborne Infectious Agents and Other Pollutants in Automobiles for Domestic Use: Potential Health Impacts and Approaches to Risk Mitigation

Theworld total of passenger cars is expected to go fromthe current one billion to \u3e2.5 billion by 2050. Cars for domestic use account for ∼74% of the world’s yearly production ofmotorized vehicles. In North America, ∼80% of the commuters use their own car with another 5.6% travelling as passengers.With the current life-expectancy of 78.6 years, the average North American spends 4.3 years driving a car! This equates to driving 101 minutes/day with a lifetime driving distance of nearly 1.3 million km inside the confined and often shared space of the car with exposure to a mix of potentially harmful pathogens, allergens, endotoxins, particulates, and volatile organics. Such risks may increase in proportion to the unprecedented upsurge in the numbers of family cars globally. Though new technologies may reduce the levels of air pollution from car exhausts and other sources, they are unlikely to impact our in-car exposure to pathogens. Can commercial in-car air decontamination devices reduce the risk from airborne infections and other pollutants?We lack scientifically rigorous protocols to verify the claims of such devices. Here we discuss the essentials of a customized aerobiology facility and test protocols to assess such devices under field-relevant conditions

Abortion fraud cases: A sociological analysis of fictitious crashes and scams involving insurance firms

The purpose of this study is to provide a sociological analysis of abortion occurrences with the aim of investigating factors cited by insurance companies about pregnant women. A qualitative research method has been used to gather field information and its tools are based on documents and files of interviews conducted with a number of women swindlers and their accomplices as well as experts and traffic police. The statistical population is 138 files of related documents, of which 15 were selected by a simple random sampling. There are also 58 women swindlers, gang associates, experts and traffic police officers who were purposefully selected to saturate the data and in-depth semi-structured interviews were conducted with them. Validity and reliability were obtained based on the views of Marshall and Rasuman (1998). Due to the quality of the work, the analysis method was performed simultaneously with data collection, open and axial coding and compression by designing basic and mediating themes and then the main themes by using Max Qioda software. The results showed that individual, family, social, economic, political and cultural aspects are influential and motivating factors for criminals, but the most important can be economic and poverty. Also, fraudsters, by knowing and exploiting the weaknesses and legal gaps and sometimes using non-Iranians (Afghans), poor families, forged and prepared identity cards and obtained them through responsible people and infiltrating government agencies and insurance companies

Post-Partum Pituitary Insufficiency and Livedo Reticularis Presenting a Diagnostic Challenge in a Resource Limited Setting in Tanzania: A Case Report, Clinical Discussion and Brief Review of Existing Literature.

Pituitary disorders following pregnancy are an important yet under reported clinical entity in the developing world. Conversely, post partum panhypopituitarism has a more devastating impact on women in such settings due to high fertility rates, poor obstetric care and scarcity of diagnostic and therapeutic resources available. A 37 year old African female presented ten years post partum with features of multiple endocrine deficiencies including hypothyroidism, hypoadrenalism, lactation failure and secondary amenorrhea. In addition she had clinical features of an underlying autoimmune condition. These included a history of post-partum thyroiditis, alopecia areata, livedo reticularis and deranged coagulation indices. A remarkable clinical response followed appropriate hormone replacement therapy including steroids. This constellation has never been reported before; we therefore present an interesting clinical discussion including a brief review of existing literature. Post partum pituitary insufficiency is an under-reported condition of immense clinical importance especially in the developing world. A high clinical index of suspicion is vital to ensure an early and correct diagnosis which will have a direct bearing on management and patient outcome