Fabrication and structural analysis of ZnO coated fiber optic phase modulators

Fiber optic modulators were fabricated by coating optical fibers with electrode and piezoelectric ZnO layers. The techniques of piezoelectric fiber optic modulator (PFOM) fabrication are presented, and the microstructure and crystallographic texture of the coatings are analyzed. In order to produce thick (approximately 5 μm) ZnO coatings, it was necessary to study the reactive dc magnetron sputtering process in O2/Ar gas mixtures under conditions close to the transition between an oxidized and nonoxidized Zn target surface. In situ quartz crystal microbalance measurements of the deposition rate revealed thee distinct regions in the deposition rate (R) vs oxygen partial pressure behavior, at constant total pressure, for sputtering under conditions that provided an oxidized Zn target surface. Additionally, a transition between oxygen and argon dominated sputtering as observed by varying the sputtering pressure while maintaining a constant The transition between oxygen and argon dominated sputtering influences R to varying extents within the three R vs regions for an oxidized target surface. Correlations among the cathode current and voltage, deposition rate, and gas flow rate are presented to give a better understanding of the reactive sputtering processes occurring at the oxidized Zn target surface. Sputtering conditions optimized for a high ZnO deposition rate were used to produce 〈001〉 radially oriented ZnO fiber coatings for PFOM devices that can produce optical phase shifts as large as 0.38 rad/

Initial Characterization of the FlgE Hook High Molecular Weight Complex of

The spirochete periplasmic flagellum has many unique attributes. One unusual characteristic is the flagellar hook. This structure serves as a universal joint coupling rotation of the membrane-bound motor to the flagellar filament. The hook is comprised of about 120 FlgE monomers, and in most bacteria these structures readily dissociate to monomers (∼ 50 kDa) when treated with heat and detergent. However, in spirochetes the FlgE monomers form a large mass of over 250 kDa [referred to as a high molecular weight complex (HMWC)] that is stable to these and other denaturing conditions. In this communication, we examined specific aspects with respect to the formation and structure of this complex. We found that the Lyme disease spirochete Borrelia burgdorferi synthesized the HMWC throughout the in vitro growth cycle, and also in vivo when implanted in dialysis membrane chambers in rats. The HMWC was stable to formic acid, which supports the concept that the stability of the HMWC is dependent on covalent cross-linking of individual FlgE subunits. Mass spectrometry analysis of the HMWC from both wild type periplasmic flagella and polyhooks from a newly constructed ΔfliK mutant indicated that other proteins besides FlgE were not covalently joined to the complex, and that FlgE was the sole component of the complex. In addition, mass spectrometry analysis also indicated that the HMWC was composed of a polymer of the FlgE protein with both the N- and C-terminal regions remaining intact. These initial studies set the stage for a detailed characterization of the HMWC. Covalent cross-linking of FlgE with the accompanying formation of the HMWC we propose strengthens the hook structure for optimal spirochete motility

Photoelasticity of crystalline and amorphous silica from first principles

Based on density-functional perturbation theory we have computed from first principles the photoelastic tensor of few crystalline phases of silica at normal conditions and high pressure (quartz, $\alpha$-cristobalite, $\beta$-cristobalite) and of models of amorphous silica (containig up to 162 atoms), obtained by quenching from the melt in combined classical and Car-Parrinello molecular dynamics simulations. The computational framework has also been checked on the photoelastic tensor of crystalline silicon and MgO as prototypes of covalent and ionic systems. The agreement with available experimental data is good. A phenomenological model suitable to describe the photoelastic properties of different silica polymorphs is devised by fitting on the ab-initio data.Comment: ten figure

Socioeconomic factors influencing access to drugs from the Specialized Component of Pharmaceutical Services in Paraná-Brazil: An observational, cross-sectional retrospective study

The Specialized Component of Pharmaceutical Services (CEAF) is a crucial strategy for accessing medicines through the Brazilian Public Health System, holding the highest budgetary impact on outpatient pharmaceutical care. This study aimed to assess the association of socioeconomic factors with access to CEAF drugs in municipalities throughout Paran & aacute; from 2010 to 2019. It utilized a retrospective, observational, cross-sectional approach, evaluating dispensed medication units, medication expenditure, and average unit cost. Analyses were performed to identify a correlation between the use of CEAF drugs and socioeconomic indicators. In these 10 years, the number of dispensed units practically quadrupled, and the expenditure on these drugs doubled, from BRL 214 million to BRL 476 million. The Index of Paran & aacute; Institute for Economic and Social Development of Municipal Performance (IPDM) showed a greater association with the use of CEAF drugs, and no correlation was observed between gross domestic product (GDP) per capita and the municipal population. Overall, the IPDM index that includes income, education, and health are socioeconomic factors that influence the utilization of CEAF drugs. These findings emphasize the need for health education among users and adjustment of public policies to mitigate inequalities in the CEAF drug access for the citizens of Paran & aacute;

Measuring the Response Diversity of Ecological Communities Experiencing Multifarious Environmental Change

ABSTRACTThe diversity in organismal responses to environmental changes (i.e., response diversity) plays a crucial role in shaping community and ecosystem stability. However, existing measures of response diversity only consider a single environmental variable, whereas natural communities are commonly exposed to changes in multiple environmental variables simultaneously. Thus far, no approach exists to integrate multifarious environmental change and the measurement of response diversity. Here, we show how to consider and quantify response diversity in the context of multifarious environmental change, and in doing so introduce a distinction between response diversity to a defined or anticipated environmental change, and the response capacity to any possible set of (defined or undefined) future environmental changes. First, we describe and illustrate the concepts with empirical data. We reveal the role of the trajectory of environmental change in shaping response diversity when multiple environmental variables fluctuate over time. We show that, when the trajectory of the environmental change is undefined (i.e., there is no information or a priori expectation about how an environmental condition will change in future), we can quantify the response capacity of a community to any possible environmental change scenario. That is, we can estimate the capacity of a system to respond under a range of realistic or extreme environmental changes, with utility for predicting future responses to even multifarious environmental change. Finally, we investigate determinants of response diversity within a multifarious environmental change context. We identify factors such as the diversity of species responses to each environmental variable, the relative influence of different environmental variables and temporal means of environmental variable values as important determinants of response diversity. In doing so, we take an important step towards measuring and understanding the insurance capacity of ecological communities exposed to multifarious environmental change

Fabrication and structural analysis of ZnO coated fiber optic phase modulators

Fiber optic modulators were fabricated by coating optical fibers with electrode and piezoelectric ZnO layers. The techniques of piezoelectric fiber optic modulator (PFOM) fabrication are presented, and the microstructure and crystallographic texture of the coatings are analyzed, Ln order to produce thick (approximately 5 mu m) ZnO coatings, it was necessary to study the reactive de magnetron sputtering process in O-2/Ar gas mixtures under conditions close to the transition between an oxidized and nonoxidized Zn target surface. In situ quartz crystal microbalance measurements of the deposition rate revealed thee distinct regions in the deposition rate (R) vs oxygen partial pressure (P-o2) behavior, at constant total pressure, for sputtering under conditions that provided an oxidized Zn target surface. Additionally, a transition between oxygen and argon dominated sputtering as observed by varying the sputtering pressure while maintaining a constant P-o2. The transition between oxygen and argon dominated sputtering influences R to varying extents within the three R vs P-o2 regions for an oxidized target surface. Correlations among the cathode current and voltage, deposition rate, and gas flow rate are presented to give a better understanding of the reactive sputtering processes occurring at the oxidized Zn target surface. Sputtering conditions optimized for a high ZnO deposition rate were used to produce [001] radially oriented ZnO fiber coatings for PFOM devices that can produce optical phase shifts as large as 0.38 rad/V