O-band N-rich silicon nitride MZI based on GST

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordWe have experimentally demonstrated an O-band Mach-Zehnder interferometer (MZI) based on a N-rich silicon nitride platform combined with Ge2Sb2Te5 for future optical communication applications. The device operation relies on controlling the waveguide’s losses using a phase change material cell which can be changed from amorphous (lowloss) to crystalline (high-loss). An extinction ratio (ER) as high as 11 dB was obtained between the amorphous (ON) and the crystalline (OFF) states of the MZI optical building block. The insertion loss of the MZI structure per cell unit length was measured to be as high as 0.87 dB/µm in OFF state and as low as 0.064 dB/µm in ON state for TM polarisation.Engineering and Physical Sciences Research Council (EPSRC

Reconfigurable photonic integrated circuits (RPICs) based on functional materials for integrated optical communication applications

This is the final version. Available from the publisher via the DOI in this record.In this work we combine the already mature silicon and silicon nitride platforms with novel reconfigurable materials such as 2D materials, liquid crystals and phase change materials. An actively reconfigurable 1D photonic crystal multi-channel filter based on Si-on-insulator and liquid crystal platforms is demonstrated with extraordinary large quality factor, Q ∼ 104 . A complete study and design of an optical routing and multilevel volatile photonic memory based on graphene capacitor concept for future high performance computing using Silicon rich nitride is shown with a bandwidth of 64 GHz and energy power consumption per bit as low as 0.22 pJ. Finally, an optical switch based on germanium-antimony-tellurium phase change material (GST) is experimentally demonstrated for O-band operation with the extinction ratio as high as 10 dB between the amorphous and the crystalline statesEngineering and Physical Sciences Research Council (EPSRC

Hedonic perception and preference analysis of double cream cheeses formulated with raw and pasteurized milk

Objective: To compare the characteristics of double cream cheeses made with raw and pasteurized milk per liking and preference level. Design/Methodology/Approach: Cheeses from three brands were evaluated: Santa Teresa, Montero, and Colegio de Postgraduados (CP). The first two cheeses were formulated with raw milk, while the CP cheese was formulated with pasteurized milk inoculated with lactic cultures. The hedonic perception study was carried out in monadic series with 19 volunteers who blind tasted the three types of cheese. The evaluation attributes were: appearance, taste, aroma, and general acceptability on a 9-point scale; and saltiness, acidity, and creaminess on a 3-point scale (JAR). Preferences were evaluated by rank and multiple comparison tests. Results: No differences were found in the aroma, taste, and texture liking level of the cheeses (p>0.05); nevertheless, there were differences in the appearance and general acceptance (p˂0.05). The general acceptance of the CP cheese was significantly lower than that of the two raw milk cheeses (p˂0.05). The penalty analysis showed that low acidity and low creaminess attributes are related to a low general acceptance (p˂0.05). Limitations/Implications: The study has enough evaluations for statistical tests. Findings/Conclusions: Raw milk cheeses obtained the highest marks in all attributes. Determining if there are other sensory attributes —in addition to those that were the subject of this study— will help to explain the greater preference and global acceptance of raw milk cheeses

Evaluation of fermentative activity of lactic cultures for dehydrated yogurt with the use of different additives

Objective: To evaluate the fermentative activity of dehydrated lactic cultures with the use of various additives and vacuum drying, using yogurt as a model system. Design/methodology/approach: The yogurt was made with commercial lactic cultures (YF-L705 Yo-Flex CHR HANSEN) inoculated in whole milk incubated for 4 h/42°C. The yogurt was centrifuged at 6,000 rpm/15 min/4°C. The supernatant was removed, and the following additives were added to the precipitate: 1) SN, without additives, 2) Glycerol, 3) Calcium carbonate, 4) Yeast extract, 5) Glycerol and calcium carbonate, 6) Glycerol, calcium carbonate and yeast extract. The drying of 6 treatments was done up to 96h inside vacuum desiccators. Weight and moisture loss were recorded at 0, 24, 48, 72 and 96h. The dehydrated portions with the additives 1,2,3,4,5,6 was used as inoculums in milk for the production of yogurt; recording the drop in pH up to 24h and FTIR. As a control, non-dehydrated and lyophilized portion of yogurt were used. Results: The drying time at constant weight was 3 days. Dehydrated cultures containing yeast extract and calcium carbonate are associated with faster milk fermentation activity (p ≤ 0.05). Yoghurts manufactured with fresh cultures take 4 hours to ferment, dehydrated ones take over 12 hours. Infrared spectra show that yogurts produced with fresh or dried strains are of similar qualities. Study limitations/implications: The fermentative activity in dehydrated foods improves when alkalis are added, such as calcium carbonate, which is an antacid and releases CO2 upon contact with water and acid, stimulating anaerobiosis. Infrared spectra show that yogurts produced with fresh or dried strains are of similar qualities. Findings/conclusions: The best model to present the fermentation pH change curve is a Boltzman sigmoidal function. Yogurts with fresh or dried cultures differed in the time at which the milk is fermented. The fermentative activity in dehydrated foods improves when alkalis are added, such as calcium carbonate, which is an antacid and releases CO2 on contact with water, stimulating anaerobiosis. Infrared spectra show that yogurts produced with fresh or dried strains are of similar qualities.Objective: To evaluate the fermentative activity of dehydrated lactic cultures with the use of different additives and vacuum desiccation, using yogurt as model system. Design/methodology/approach: The yogurt was elaborated with commercial lactic cultures (YF-L705 Yo-Flex CHR HANSEN) and whole milk incubated at 42 °C for 4 h. Yogurt was centrifuged at 6,000 rpm/15 min/4 °C. The supernatant was eliminated and with the precipitate, 6 treatments were established by addition of additives: T1, Without additive, T2, Glycerol, T3, Calcium carbonate, T4, Yeast extract, T5, Glycerol, and T6, Glycerol, Calcium carbonate and Yeast extract; non-dehydrated and freeze-dried yogurt was used as control: T7 and T8, respectively. The precipitate of the treatments with additives was dehydrated in a silica gel in a desiccator and under vacuum conditions. The weight loss was recorded at 0, 24, 48, 72 and 96 h. The precipitate with dehydrated additives was used as milk inoculates for yogurt elaboration. The change of pH was recorded at 0, 1, 2, 3, 4, 5, 6, 7, 8 and 24 h. With the pH and the fermentation time, a model was established to present the change curve in fermentation pH and the Fourier transform infrared spectroscopy (FTIR). Results: The drying time to constant weight was 3 days. The fermentation pH change curve was a Boltzman sigmoidal function and analysis of variance was conducted with its parameters to assess the different fermentation speeds of the different treatments. The dehydrated cultures with Yeast Extract and Calcium Carbonate are associated with a higher fermentation activity of the milk (p < 0.05). The yogurts manufactured with fresh cultures take 4 to 5 h to ferment and the dehydrated ones take more than 10 h. The infrared spectra showed that the quality of the yogurts produced with fresh or dry cultures are similar, which agrees with other studies. Limitations on study/implications: The dehydrated inoculated with the additives can be used to make yogurt with similar quality as to when inoculate with fresh culture is used, with the disadvantage of the fermentation time being longer. It is possible that this methodology can be used to dehydrate other inoculates based on lactic bacteria, but their effectiveness would have to be assessed experimentally. Findings/conclusions: This study shows an alternative method to dehydrate lactic bacteria in the laboratory with equipment of relatively easy access for any laborator

Changes in dietary fiber intake in mice reveal associations between colonic mucin O-glycosylation and specific gut bacteria

The colonic mucus layer, comprised of highly O-glycosylated mucins, is vital to mediating host-gut microbiota interactions, yet the impact of dietary changes on colonic mucin O-glycosylation and its associations with the gut microbiota remains unexplored. Here, we used an array of omics techniques including glycomics to examine the effect of dietary fiber consumption on the gut microbiota, colonic mucin O-glycosylation and host physiology of high-fat diet-fed C57BL/6J mice. The high-fat diet group had significantly impaired glucose tolerance and altered liver proteome, gut microbiota composition, and short-chain fatty acid production compared to normal chow diet group. While dietary fiber inclusion did not reverse all high fat-induced modifications, it resulted in specific changes, including an increase in the relative abundance of bacterial families with known fiber digesters and a higher propionate concentration. Conversely, colonic mucin O-glycosylation remained similar between the normal chow and high-fat diet groups, while dietary fiber intervention resulted in major alterations in O-glycosylation. Correlation network analysis revealed previously undescribed associations between specific bacteria and mucin glycan structures. For example, the relative abundance of the bacterium Parabacteroides distasonis positively correlated with glycan structures containing one terminal fucose and correlated negatively with glycans containing two terminal fucose residues or with both an N-acetylneuraminic acid and a sulfate residue. This is the first comprehensive report of the impact of dietary fiber on the colonic mucin O-glycosylation and associations of these mucosal glycans with specific gut bacteria

GC-FID-MS and X-ray Diffraction for the Detailed Evaluation of the Volatiles From Senecio filaginoides

The medicinal aromatic plant Senecio filaginoides DC, which is very widespread in the Patagonia region, was harvested at the vegetative, flowering, and fructification stages. The materials were extracted by hydrodistillation, yielding in average 0.34% v/w of essential oils with a pleasant sweet and greenish scent. A total of 56 components were identified by gas chromatography using flame ionization detection and mass spectra measurements, representing 96.1%-97.6% of the total oil. The sesquiterpenoid 10αH-furanoeremophil-1-one (1) appeared as a major constituent (16.2%-26.9%) of the oil. It could be isolated by cooling the oil at 4°C, thus yielding yellow crystalline solids. Its stereochemistry was assigned by single-crystal X-ray diffraction since previous studies identified the compound with different stereochemistries. The use of classical separation and analytical methodologies remains as a very useful strategy for the correct identification of compounds present in the volatile fraction of a plant and is a route for potential industrial applications.Fil: Van Baren, Catalina Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: González, Silvia Beatriz. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Bandoni, Arnaldo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Di Leo Lira, Paola Maria del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Bucio, María A.. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Investigaciones Educativas.; MéxicoFil: Hernández Barragán, Angelina. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Investigaciones Educativas.; MéxicoFil: Joseph Nathan, Pedro. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Investigaciones Educativas.; Méxic

Alkamides Activate Jasmonic Acid Biosynthesis and Signaling Pathways and Confer Resistance to Botrytis cinerea in Arabidopsis thaliana

Alkamides are fatty acid amides of wide distribution in plants, structurally related to N-acyl-L-homoserine lactones (AHLs) from Gram-negative bacteria and to N- acylethanolamines (NAEs) from plants and mammals. Global analysis of gene expression changes in Arabidopsis thaliana in response to N-isobutyl decanamide, the most highly active alkamide identified to date, revealed an overrepresentation of defense-responsive transcriptional networks. In particular, genes encoding enzymes for jasmonic acid (JA) biosynthesis increased their expression, which occurred in parallel with JA, nitric oxide (NO) and H2O2 accumulation. The activity of the alkamide to confer resistance against the necrotizing fungus Botrytis cinerea was tested by inoculating Arabidopsis detached leaves with conidiospores and evaluating disease symptoms and fungal proliferation. N-isobutyl decanamide application significantly reduced necrosis caused by the pathogen and inhibited fungal proliferation. Arabidopsis mutants jar1 and coi1 altered in JA signaling and a MAP kinase mutant (mpk6), unlike salicylic acid- (SA) related mutant eds16/sid2-1, were unable to defend from fungal attack even when N-isobutyl decanamide was supplied, indicating that alkamides could modulate some necrotrophic-associated defense responses through JA-dependent and MPK6-regulated signaling pathways. Our results suggest a role of alkamides in plant immunity induction

Nitrogen forms affect root structure and water uptake in the hybrid poplar

The study analyses the effects of two different forms of nitrogen fertilisation (nitrate and ammonium) on root structure and water uptake of two hybrid poplar (Populus maximowiczii x P. balsamifera) clones in a field experiment. Water uptake was studied using sap flow gauges on individual proximal roots and coarse root structure was examined by excavating 18 whole-root systems. Finer roots were scanned and analyzed for architecture. Nitrogen forms did not affect coarse-root system development, but had a significant effect on fine-root development. Nitrate-treated trees presented higher fine:coarse root ratios and higher specific root lengths than control or ammonium treated trees. These allocation differences affected the water uptake capacity of the plants as reflected by the higher sapflow rate in the nitrate treatment. The diameter of proximal roots at the tree base predicted well the total root biomass and length. The diameter of smaller lateral roots also predicted the lateral root mass, length, surface area and the number of tips. The effect of nitrogen fertilisation on the fine root structure translated into an effect on the functioning of the fine roots forming a link between form (architecture) and function (water uptake)

A mechanistic framework for auxin dependent Arabidopsis root hair elongation to low external phosphate

Phosphate (P) is an essential macronutrient for plant growth. Roots employ adaptive mechanisms to forage for P in soil. Root hair elongation is particularly important since P is immobile. Here we report that auxin plays a critical role promoting root hair growth in Arabidopsis in response to low external P. Mutants disrupting auxin synthesis (taa1) and transport (aux1) attenuate the low P root hair response. Conversely, targeting AUX1 expression in lateral root cap and epidermal cells rescues this low P response in aux1. Hence auxin transport from the root apex to differentiation zone promotes auxin-dependent hair response to low P. Low external P results in induction of root hair expressed auxin-inducible transcription factors ARF19, RSL2, and RSL4. Mutants lacking these genes disrupt the low P root hair response. We conclude auxin synthesis, transport and response pathway components play critical roles regulating this low P root adaptive response