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https://www.readbyqxmd.com/read/28651354/cambial-response-of-norway-spruce-to-modified-carbon-availability-by-phloem-girdling
#1
Andrea Winkler, Walter Oberhuber
We tested the hypothesis that increase in carbon (C) availability in Norway spruce saplings (Picea abies (L.) Karst.) intensifies cambial cell division and increases cell lumen diameter (CLD) and cell wall thickness (CWT) when water availability is adequate. To accomplish this, we experimentally subjected 6-year-old P. abies saplings (n = 80 trees) to two levels of soil humidity (watered versus drought conditions) and manipulated tree C status by physically blocking phloem transport at three girdling dates (GDs)...
June 23, 2017: Tree Physiology
https://www.readbyqxmd.com/read/28650147/structural-basis-for-aza-glycine-stabilization-of-collagen
#2
Alexander Kasznel, Yitao Zhang, Yang Hai, David M Chenoweth
Previously, we have demonstrated that replacement of the strictly conserved glycine in collagen with aza-glycine provides a general solution for stabilizing triple helical collagen peptides.1-2 The additional hydrogen bond and conformational constraints provided by aza-glycine increases the thermal stability and rate of folding in collagen peptides composed of Pro-Hyp-Gly triplet repeats, allowing for truncation to the smallest self-assembling peptide systems observed to date. Here we show that aza-glycine substitution enhances the stability of an arginine-containing collagen peptide and provide a structural basis for this stabilization with an atomic resolution crystal structure...
June 26, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28649867/study-of-isotopes-of-carbon-thorium-and-uranium-in-travertine-and-thermal-spring-samples-implications-for-effects-of-changes-in-geochemical-environment-and-processes
#3
Alexander I Malov
Data on modern radiocarbon activity in the old travertine formations of the Pymvashor hydrothermal system were used, in combination with (230)Th/U dating of the travertine, to estimate the (14)C contents of the total dissolved inorganic carbon in the ancient thermal water at the time of precipitation of the travertine ((14)Ccalc). With the known values of (14)Ccalc and average age of the thermal water, and under the assumption that the residence time of the water in aquifer was constant over the last 13.9 ± 1...
June 26, 2017: Isotopes in Environmental and Health Studies
https://www.readbyqxmd.com/read/28646765/historical-record-of-polychlorinated-biphenyls-pcbs-and-special-occurrence-of-pcb-209-in-a-shallow-fresh-water-lake-from-eastern-china
#4
Shouliang Huo, Chaocan Li, Beidou Xi, Zhiqiang Yu, Kevin M Yeager, Fengchang Wu
Concentrations of polychlorinated biphenyls (PCBs) were measured in dated sediment cores collected from the fifth largest freshwater lake in China, Lake Chaohu, to investigate PCB temporal trends, accumulation, and environmental fate. Total PCB concentrations in Lake Choahu sediments ranged from 0.03 to 24.11 ng g(-1) (d.w.). PCB 209 was the dominant congener, accounting for 45.5%-83.9% of total PCBs detected after the mid-20th century. All PCB congeners were positively correlated with total organic carbon (TOC) concentrations...
June 18, 2017: Chemosphere
https://www.readbyqxmd.com/read/28642741/the-hyperarid-core-of-the-atacama-desert-an-extremely-dry-and-carbon-deprived-habitat-of-potential-interest-for-the-field-of-carbon-science
#5
Armando Azua-Bustos, Carlos González-Silva, Gino Corsini
The Atacama Desert in Chile is the driest and oldest desert on Earth, also considered one of the best Mars analog models. Here, several heterotrophic microbial communities have been discovered in its driest regions, with the ones present in the soil subsurface being one of the most interesting due to its existence in a habitat with almost no water available and almost undetectable organic carbon sources. Our recent discovery of the driest site of the Atacama known to date (and the heterotrophic microbial species that are able to survive in this site) reaffirms the opportunity to better characterize the physiological and molecular mechanisms that these species use to detect, mobilize, incorporate and use carbon under these extremely harsh conditions...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28640625/dust-effects-on-nucleation-kinetics-and-nanoparticle-product-size-distributions-illustrative-case-study-of-a-prototype-ir-0-n-transition-metal-nanoparticle-formation-system
#6
Saim Özkar, Richard G Finke
The question is addressed if dust is kinetically important in the nucleation and growth of Ir(0)n nanoparticles formed from [Bu4N]5Na3(1,5-COD)Ir(I)·P2W15Nb3O62 (hereafter [(COD)Ir·POM](8-)), reduced by H2 in propylene carbonate solvent. Following a concise review of the (often-neglected) literature addressing dust in nucleation phenomena dating back to the late 1800s, the nucleation and growth kinetics of the [(COD)Ir·POM](8-) precatalyst system are examined for the effects of 0.2 μm microfiltration of the solvent and precatalyst solution, of rinsing the glassware with that microfiltered solvent, of silanizing the glass reaction vessel, for the addition of <0...
June 22, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28640524/carbon-coated-li3-vo4-spheres-as-constituents-of-an-advanced-anode-material-for-high-rate-long-life-lithium-ion-batteries
#7
Laifa Shen, Shuangqiang Chen, Joachim Maier, Yan Yu
Lithium-ion batteries are receiving considerable attention for large-scale energy-storage systems. However, to date the current cathode/anode system cannot satisfy safety, cost, and performance requirements for such applications. Here, a lithium-ion full battery based on the combination of a Li3 VO4 anode with a LiNi0.5 Mn1.5 O4 cathode is reported, which displays a better performance than existing systems. Carbon-coated Li3 VO4 spheres comprising nanoscale carbon-coating primary particles are synthesized by a morphology-inheritance route...
June 22, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28639317/factors-influencing-co2-and-energy-penalty-of-co2-mineralization-processes
#8
Pavan Kumar Naraharisetti, Tze Yuen Yeo, Jie Bu
Carbon mineralization is one of the CCUS (Carbon Capture Utilization, and Storage) technologies that can capture large quantities of CO2 and convert it into stable carbonate products that can be stored easily. Several CO2 mineralization processes have been proposed, however there are no commercial scale projects because there are still significant issues that need to be improved upon before commercialization can take place. In this work, we evaluate the CO2 and energy penalty related to the most well-known type of mineralization process to date, where the mineralization reaction takes place directly under aqueous conditions, high pressures and temperatures and compared it with newer T-P swing process and Ball mill reactor process which are under development...
June 21, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28637476/eliminating-acetate-formation-improves-citramalate-production-by-metabolically-engineered-escherichia-coli
#9
Naga Sirisha Parimi, Ian A Durie, Xianghao Wu, Afaq M M Niyas, Mark A Eiteman
BACKGROUND: Citramalate, a chemical precursor to the industrially important methacrylic acid (MAA), can be synthesized using Escherichia coli overexpressing citramalate synthase (cimA gene). Deletion of gltA encoding citrate synthase and leuC encoding 3-isopropylmalate dehydratase were critical to achieving high citramalate yields. Acetate is an undesirable by-product potentially formed from pyruvate and acetyl-CoA, the precursors of citramalate during aerobic growth of E. coli. This study investigated strategies to minimize acetate and maximize citramalate production in E...
June 21, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28635185/antipulverization-electrode-based-on-low-carbon-triple-shelled-superstructures-for-lithium-ion-batteries
#10
Lianhai Zu, Qingmei Su, Feng Zhu, Bingjie Chen, Huanhuan Lu, Chengxin Peng, Ting He, Gaohui Du, Pengfei He, Kai Chen, Shihe Yang, Jinhu Yang, Huisheng Peng
The realization of antipulverization electrode structures, especially using low-carbon-content anode materials, is crucial for developing high-energy and long-life lithium-ion batteries (LIBs); however, this technology remains challenging. This study shows that SnO2 triple-shelled hollow superstructures (TSHSs) with a low carbon content (4.83%) constructed by layer-by-layer assembly of various nanostructure units can withstand a huge volume expansion of ≈231.8% and deliver a high reversible capacity of 1099 mAh g(-1) even after 1450 cycles...
June 21, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28633067/microbial-electrosynthesis-of-butyrate-from-carbon-dioxide-production-and-extraction
#11
Pau Batlle-Vilanova, Ramon Ganigué, Sara Ramió-Pujol, Lluís Bañeras, Gerard Jiménez, Manuela Hidalgo, M Dolors Balaguer, Jesús Colprim, Sebastià Puig
To date acetate is the main product of microbial electrosynthesis (MES) from carbon dioxide (CO2). In this work a tubular bioelectrochemical system was used to carry out MES and enhance butyrate production over the other organic products. Batch tests were performed at a fixed cathode potential of -0.8V vs SHE. The reproducibility of the results according to previous experiments was validated in a preliminary test. According to the literature butyrate production could take place by chain elongation reactions at low pH and high hydrogen partial pressure (pH2)...
June 15, 2017: Bioelectrochemistry
https://www.readbyqxmd.com/read/28629008/multi-walled-carbon-nanotubes-graphene-oxide-hybrid-and-nanohydroxyapatite-composite-a-novel-coating-to-prevent-dentin-erosion
#12
Sídnei Nahorny, Hudson Zanin, Vinie Abreu Christino, Fernanda Roberta Marciano, Anderson Oliveira Lobo, Luís Eduardo Silva Soares
To date is emergent the development of novel coatings to protect erosion, especially to preventive dentistry and restorative dentistry. Here, for the first time we report the effectiveness of multi-walled carbon nanotube/graphene oxide hybrid carbon-base material (MWCNTO-GO) combined with nanohydroxyapatite (nHAp) as a protective coating for dentin erosion. Fourier transform Raman spectroscopy (FT-Raman), scanning electron (SEM), and transmission electron (TEM) microscopy were used to investigated the coatings and the effect of acidulated phosphate fluoride gel (APF) treatment on bovine teeth root dentin before and after erosion...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28628318/third-generation-light-driven-symmetric-molecular-motors
#13
Jos C M Kistemaker, Peter Stacko, Diederik Roke, Alexander Thomas Wolters, G Henrieke Heideman, Mu-Chieh Chang, Pieter van der Meulen, Johan Visser, Edwin Otten, Ben L Feringa
Symmetric molecular motors based on two overcrowded alkenes with a notable absence of a stereogenic center show potential to function as novel mechanical systems in the development of more advanced nanomachines and controlled motion over surfaces. Elucidation of the key parameters and limitations of these third generation motors is essential for the design of optimized molecular machines based on light-driven rotary motion. Herein we demonstrate the thermal and photochemical rotational behavior of a series of third generation light-driven molecular motors...
June 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28626611/discrimination-factors-of-carbon-and-nitrogen-stable-isotopes-in-meerkat-feces
#14
Shaena Montanari
Stable isotope analysis of feces can provide a non-invasive method for tracking the dietary habits of nearly any mammalian species. While fecal samples are often collected for macroscopic and genetic study, stable isotope analysis can also be applied to expand the knowledge of species-specific dietary ecology. It is somewhat unclear how digestion changes the isotope ratios of animals' diets, so more controlled diet studies are needed. To date, most diet-to-feces controlled stable isotope experiments have been performed on herbivores, so in this study I analyzed the carbon and nitrogen stable isotope ratios in the diet and feces of the meerkat (Suricata suricatta), a small omnivorous mammal...
2017: PeerJ
https://www.readbyqxmd.com/read/28623382/carbon-and-hydrogen-isotope-fractionation-during-aerobic-biodegradation-of-quinoline-and-3-methylquinoline
#15
Mingchao Cui, Wenbing Zhang, Jun Fang, Qianqiong Liang, Dongxuan Liu
Compound-specific isotope analysis has been used extensively to investigate the biodegradation of various organic pollutants. To date, little isotope fractionation information is available for the biodegradation of quinolinic compounds. In this study, we report on the carbon and hydrogen isotope fractionation during quinoline and 3-methylquinoline aerobic microbial degradation by a Comamonas sp. strain Q10. Degradation of quinoline and 3-methylquinoline was accompanied by isotope fractionation. Large hydrogen and small carbon isotope fractionation was observed for quinoline while minor carbon and hydrogen isotope fractionation effects occurred for 3-methylquinoline...
June 16, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28622923/consistent-c3-plant-habitat-of-hominins-during-400-300%C3%A2-ka-at-the-longyadong-cave-site-luonan-basin-central-china-revealed-by-stable-carbon-isotope-analyses-of-loess-deposits
#16
Hongyan Zhang, Huayu Lu, Shejiang Wang, Enlou Zhang, Richard Cosgrove, Wenchao Zhang, Lu Li
The proportions of woody and grassland taxa in terrestrial ecosystems played an important role in the origin and evolution of early Palaeolithic hominins. However the influence of ecosystem changes on hominin behavior and adaptations in Asia has not been studied in detail. Hominins have exploited the Luonan Basin in the Eastern Qinling Mountains, central China, since the early Paleolithic. Dated sites, consisting of alternating loess and soil deposits with in situ artefacts, are common in the region, and provide a detailed record of Early to Middle Pleistocene hominin environments...
July 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28622013/acetazolamide-usage-in-severe-chronic-obstructive-pulmonary-disease-pros-and-cons
#17
Rosemary Adamson, Erik R Swenson
Acetazolamide is a carbonic anhydrase (CA) inhibitor sometimes used as a respiratory stimulant for patients with COPD with the goal of improving oxygenation, reducing carbon dioxide retention and aiding liberation from mechanical ventilation and/or attempting to correct a metabolic alkalosis. However, the net effect of CA inhibition is multifactorial and complex since CA is inhibited in many tissues that may negatively affect the patient with lung disease. The full impact of acetazolamide and other CA inhibitors depends critically on dosing, age, and pulmonary, renal, hepatic, hematological, and respiratory muscle function and reserves...
June 16, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28606738/engineering-high-level-production-of-fatty-alcohols-by-saccharomyces-cerevisiae-from-lignocellulosic-feedstocks
#18
Leo d'Espaux, Amit Ghosh, Weerawat Runguphan, Maren Wehrs, Feng Xu, Oliver Konzock, Ishaan Dev, Melissa Nhan, Jennifer Gin, Amanda Reider Apel, Christopher J Petzold, Seema Singh, Blake A Simmons, Aindrila Mukhopadhyay, Héctor García Martín, Jay D Keasling
Fatty alcohols in the C12-C18 range are used in personal care products, lubricants, and potentially biofuels. These compounds can be produced from the fatty acid pathway by a fatty acid reductase (FAR), yet yields from the preferred industrial host Saccharomyces cerevisiae remain under 2% of the theoretical maximum from glucose. Here we improved titer and yield of fatty alcohols using an approach involving quantitative analysis of protein levels and metabolic flux, engineering enzyme level and localization, pull-push-block engineering of carbon flux, and cofactor balancing...
June 10, 2017: Metabolic Engineering
https://www.readbyqxmd.com/read/28602091/assessing-spatial-variability-of-grape-skin-flavonoids-at-the-vineyard-scale-based-on-plant-water-status-mapping
#19
Luca Brillante, Johann Martínez-Luscher, Runze Yu, Cassandra M Plank, Luis Sanchez, Terrence L Bates, Charles Brenneman, Anita Oberholster, S Kaan Kurtural
Plant water stress affects grape (Vitis vinifera L. cv. Cabernet Sauvignon) berry composition and is variable in space due to variations in the physical environment at the growing site. We monitored the natural variability of grapevine water stress by stem water potential (Ψstem) and leaf gas exchange in an equi-distant grid in a commercial vineyard. Spatial differences were measured and related to topographical variation by modeling. Geospatial analysis and clustering allowed researchers to differentiate the vineyard block into two distinct zones having severe and moderate water stress where it varied by 0...
June 26, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28601651/plant-carbon-nourishment-of-arbuscular-mycorrhizal-fungi
#20
REVIEW
Ronelle Roth, Uta Paszkowski
Reciprocal nutrient exchange between the majority of land plants and arbucular mycorrhizal (AM) fungi is the cornerstone of a stable symbiosis. To date, a dogma in the comprehension of AM fungal nourishment has been delivery of host organic carbon in the form of sugars. More recently a role for lipids as alternative carbon source or as a signalling molecule during AM symbiosis was proposed. Here we review the symbiotic requirement for carbohydrates and lipids across developmental stages of the AM symbiosis...
June 8, 2017: Current Opinion in Plant Biology
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