Immobilization of Yeast on Polymeric Supports

Biocatalysts (enzymes and whole cells) play a crucial role in industrial processes allowing for efficient production of many important compounds, but their use has been limited because of the considerably unstable nature of enzymes. Immobilization often protects enzymes from environmental stresses such as pH, temperature, salts, solvents, inhibitors and poisons. Immobilization of cells containing specific enzymes has further advantages such as elimination of long and expensive procedures for enzymes separation and purification and it is vital to expand their application by enabling easy separation and purification of products from reaction mixtures and efficient recovery of catalyst. This review focuses on organic polymers (natural and synthetic) used as matrices for immobilization of microorganisms, mainly baker’s yeasts and potential application of immobilized cells in the chemical, pharmaceutical, biomedical and food industries

Obtención de shortenings cero-trans con alta estabilidad termo-oxidativa por transesterificación enzimática

Novel zero-trans frying shortenings were formed by enzymatic transesterification by exploring a palm stearin and canola oil mixture and stearic acid as substrates. Both immobilized (Novozym 435, Lipase PS “Amano” IM) and non-immobilized (Lipomod TM 34P) enzymes were applied as biocatalysts. Palmitic acid, the fatty acid which defines the proper type of crystal formation, was present at the 15% level in the reaction mixtures. The novel structured lipids had comparable physical properties and offered similar frying performance to those of commercial shortening. Needle-shaped crystals were predominant both in the transesterification products and the commercial frying shortening. Furthermore, solid fat content profiles of the zero-trans structured lipids produced by Novozym 435 and Lipase PS “Amano” IM were close to those of the commercial shortening.Los innovadores shortenings cero-trans para frituras se obtenían por transesterificación enzimática utilizando como sustratos una mezcla de estearina de palma con aceite de cánola y ácido esteárico. Tanto las enzimas inmovilizadas (Novozym 435, Lipase PS “Amano” IM) como las no inmovilizadas (Lipomod TM 34P) fueron aplicadas como biocatalizadores. El contenido de ácido palmítico, el ácido graso que define el tipo adecuado de formación cristalina, fue del 15% en las mezclas de reacción. Los lípidos estructurados innovadores tenían propiedades físicas comparables a los shortenings comerciales y estabilidad de oxidación térmica similar en proceso de fritura. Los cristales en forma de aguja predominaban tanto en los productos de transesterificación como en los shortenings para frituras disponible en el mercado. Además, los perfiles de contenido de grasa sólida de los lípidos estructurados cero trans producidos por Novozym 435 y Lipase PS “Amano” IM eran similares a los perfiles de los shortenings comerciales

Prenatal exposure to fine particles and polycyclic aromatic hydrocarbons and birth outcomes : a two-pollutant approach

Background Previous epidemiologic studies have considered the effects of individual air pollutants on birth outcomes, whereas a multiple-pollutant approach is more relevant to public health policy. Objectives The present study compared the observed effect sizes of prenatal fine particulate matter ( PM2.5) and polycyclic aromatic hydrocarbons (PAH) (a component of PM2.5) exposures on birth outcome deficits, assessed by the single vs. two-pollutant approaches. Methods The study sample included 455 term infants born in Krakow to non-smoking mothers, among whom personal exposures to PM2.5 and PAH were monitored in the second trimester of pregnancy. The exposure effect estimates (unstandardized and standardized regression coefficients) on birth outcomes were determined using evant covariates. Results In the single-pollutant approach, each pollutant was inversely associated with all birth outcomes. The effect size of prenatal PAH exposure on birth weight and length was twice that of PM2.5, in terms of standardized coefficients. In the two-pollutant approach, the negative effect of PM2.5 on birth weight and length, adjusted for PAH exposure, lost its significance. The standardized effect of PAH on birth weight was 10-fold stronger ($\beta$ = -0.20, $\rho$ = 0.004) than that estimated for PM2.5 ($\beta$ = -0.02, $\rho$ = 0.757). Conclusion The results provide evidence that PAH had a greater impact on several measures of fetal development, especially birth weight, than PM2.5. Though in the singlepollutant models PM2.5 had a significant impact on birth outcomes, this effect appears to be mediated by PAH

Controlling spontaneous chirality in achiral materials : liquid crystal oligomers and the heliconical twist-bend nematic phase

Peer reviewedPublisher PD

A terahertz vibrational molecular clock with systematic uncertainty at the 10−1410^{-14} level

Neutral quantum absorbers in optical lattices have emerged as a leading platform for achieving clocks with exquisite spectroscopic resolution. However, the studies of these clocks and their systematic shifts have so far been limited to atoms. Here, we extend this architecture to an ensemble of diatomic molecules and experimentally realize an accurate lattice clock based on pure molecular vibration. We evaluate the leading systematics, including the characterization of nonlinear trap-induced light shifts, achieving a total systematic uncertainty of $4.6\times10^{-14}$. The absolute frequency of the vibrational splitting is measured to be 31 825 183 207 592.8(5.1) Hz, enabling the dissociation energy of our molecule to be determined with record accuracy. Our results represent an important milestone in molecular spectroscopy and THz-frequency standards, and may be generalized to other neutral molecular species with applications for fundamental physics, including tests of molecular quantum electrodynamics and the search for new interactions.Comment: 17 pages, 8 figure

Helical phases assembled from achiral molecules : Twist-bend nematic and helical filamentary B4 phases formed by mesogenic dimers

Funding Information: National Science Centre (Poland) under the grant no. 2016/22/A/ST5/00319. Special acknowledgement and thanks to professor Dong Ki Yoon's group for providing the AAO membranes.Peer reviewedPublisher PD

Neuroactive steroids in depression and anxiety disorders: Clinical studies

Certain neuroactive steroids modulate ligand-gated ion channels via non-genomic mechanisms. Especially 3 alpha-reduced pregnane steroids are potent positive allosteric modulators of the gamma-aminobutyric acid type A (GABA(A)) receptor. During major depression, there is a disequilibrium of 3 alpha-reduced neuroactive steroids, which is corrected by clinically effective pharmacological treatment. To investigate whether these alterations are a general principle of successful antidepressant treatment, we studied the impact of nonpharmacological treatment options on neuroactive steroid concentrations during major depression. Neither partial sleep deprivation, transcranial magnetic stimulation, nor electroconvulsive therapy affected neuroactive steroid levels irrespectively of the response to these treatments. These studies suggest that the changes in neuroactive steroid concentrations observed after antidepressant pharmacotherapy more likely reflect distinct pharmacological properties of antidepressants rather than the clinical response. In patients with panic disorder, changes in neuroactive steroid composition have been observed opposite to those seen in depression. However, during experimentally induced panic induction either with cholecystokinine-tetrapeptide or sodium lactate, there was a pronounced decline in the concentrations of 3 alpha-reduced neuroactive steroids in patients with panic disorder, which might result in a decreased GABAergic tone. In contrast, no changes in neuroactive steroid concentrations could be observed in healthy controls with the exception of 3 alpha,5 alpha-tetrahydrodeoxycorticosterone. The modulation of GABA(A) receptors by neuroactive steroids might contribute to the pathophysiology of depression and anxiety disorders and might offer new targets for the development of novel anxiolytic compounds. Copyright (c) 2006 S. Karger AG, Basel

Reduction of neurovascular damage resulting from microelectrode insertion into the cerebral cortex using

Penetrating neural probe technologies allow investigators to record electrical signals in the brain. The implantation of probes causes acute tissue damage, partially due to vasculature disruption during probe implantation. This trauma can cause abnormal electrophysiological responses and temporary increases in neurotransmitter levels, and perpetuate chronic immune responses. A significant challenge for investigators is to examine neurovascular features below the surface of the brain in vivo. The objective of this study was to investigate localized bleeding resulting from inserting microscale neural probes into the cortex using two-photon microscopy (TPM) and to explore an approach to minimize blood vessel disruption through insertion methods and probe design. 3D TPM images of cortical neurovasculature were obtained from mice and used to select preferred insertion positions for probe insertion to reduce neurovasculature damage. There was an 82.8 ± 14.3% reduction in neurovascular damage for probes inserted in regions devoid of major (>5 µm) sub-surface vessels. Also, the deviation of surface vessels from the vector normal to the surface as a function of depth and vessel diameter was measured and characterized. 68% of the major vessels were found to deviate less than 49 µm from their surface origin up to a depth of 500 µm. Inserting probes more than 49 µm from major surface vessels can reduce the chances of severing major sub-surface neurovasculature without using TPM.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85401/1/7_4_046011.pd