Chemical characterzation of fine particle emissions from the fireplace combustion of woods grown in the Southern United States

The fireplace combustion of wood is a significant and largely unregulated source of fine particle pollution in the United States. Source apportionment techniques that use particulate organic compounds as tracers have been successful in determining the contribution of wood smoke to ambient fine particle levels in specific areas in California. To apply these techniques to the rest of the United States, the differences in emissions profiles between different wood smoke sources and fuel types should be resolved. To this end, a series of fireplace source tests was conducted on six fuel wood species found in the Southern United States to determine fine particulate emission factors for total mass, ionic and elemental species, elemental and organic carbon, and over 250 individual organic compounds. The wood species tested, chosen for their high abundance and availability in the Southern U.S. region, were yellow poplar, white ash, sweetgum, mockernut hickory, loblolly pine, and slash pine. The differences in the emissions of compounds such as substituted phenols and resin acids help to distinguish between the smoke from hardwood and softwood combustion. Levoglucosan, a cellulose pyrolysis product which may serve as a tracer for wood smoke in general, was quantified in the emissions from all the wood species burned. The furofuran lignan, yangambin, which was emitted in significant quantities from yellow poplar combustion and not detected in any of the other North American wood smokes, is a potential species-specific molecular tracer which may be useful in qualitatively identifying particulate emissions from a specific geographical area where yellow poplar is being burned.     

Neurological Immunotoxicity from Cancer Treatment

The emergence of immune-based treatments for cancer has led to a growing field dedicated to understanding and managing iatrogenic immunotoxicities that arise from these agents. Immune-related adverse events (irAEs) can develop as isolated events or as toxicities affecting multiple body systems. In particular, this review details the neurological irAEs from immune checkpoint inhibitors (ICI) and chimeric antigen receptor (CAR) T cell immunotherapies. The recognition and treatment of neurological irAEs has variable success, depending on the severity and nature of the neurological involvement. Understanding the involved mechanisms, predicting those at higher risk for irAEs, and establishing safety parameters for resuming cancer immunotherapies after irAEs are all important fields of ongoing research.     

Malnutrition and dietary protein: evidence from China and from international comparisons

Malnutrition, as measured by anthropometric status, is a powerful risk factor for illness and elevated death rates throughout life. Understanding the relative importance of disease, dietary quantity, and dietary quality in causing malnutrition is therefore of major importance in the design of public policy. This paper contributes to the understanding of the relative importance of quantity and quality of diet by utilizing aggregate data to complement previously reported individual-level studies. Three compilations of anthropometric data--one involving subjects from 13 provinces in China, another involving subjects from 64 counties in China, and a third involving 41 populations in 40 countries--are used to examine the relative importance for human growth of inadequacies of dietary energy and protein. The analysis involves regressing average adult heights and weights against estimates of average energy and protein availability (by province, county, or country) and per capita incomes. We use protein availability in part as a marker for overall quality of the diet, while recognizing that protein is far from perfectly correlated with dietary fat or micronutrient availability. The paper discusses issues of both data quality and statistical methodology, and points to relevant resulting caveats to our conclusions. Subject to these limitations, all three analyses suggest that, at the levels of dietary intake in these populations, lower protein intake is related to growth failure whereas lower levels of energy availability are not. The protein effect appears stronger for males than for females.     

Changes in the quality parameters of seedling tea due to height and frequency of mechanical harvesting

Quality parameters of black tea change due to the use of a mechanical harvester, varying plucking round lengths and plucking heights. Compared with hand plucking, mechanically harvested teas have inferior quality as measured by volatile flavour compounds, theaflavins and caffeine. Similarly, longer plucking rounds produced inferior teas compared with shorter rounds. Raising mechanical plucking height by 2 cm from the previous plucking height caused less quality deterioration than increasing the height by 1 cm irrespective of plucking rounds.     

Exploring the prospects of the fifth quarter in the 21st century

A variable proportion of slaughtered livestock, generally referred to as the fifth quarter, is not part of the edible dressed meat and regarded as animal byproduct. In order for the fifth quarter to play a significant role in the current effort toward a circular bio-based economy, it has to successfully support food security, social inclusivity, environmental sustainability, and a viable economy. The high volume of these low-value streams and their nutrient-dense nature can facilitate their position as a very important candidate to explore within the context of a circular bio-based economy to achieve some of the United Nations Sustainable Development Goals (UN-SDGs). While these sources have been traditionally used for various applications across different cultures and industries, it seems evident that their full potential has not yet been exploited, leaving these products more like an environmental burden rather than valuable resources. With innovation and well-targeted interdisciplinary collaborations, the potential of the fifth quarter can be fully realized. The present review intends to explore these low-value streams, their current utilization, and their potential to tackle the global challenges of increasing protein demands while preventing environmental degradation. Factors that limit widespread applications of the fifth quarter across industries and cultures will also be discussed.     

Relativistic red‐black trees

This paper presents algorithms for concurrently reading and modifying a red‐black tree (RBTree). The algorithms allow wait‐free, linearly scalable lookups in the presence of concurrent inserts and deletes. They have deterministic response times for a given tree size and uncontended read performance that is at least 60% faster than other known approaches. The techniques used to derive these algorithms arise from a concurrent programming methodology called relativistic programming. Relativistic programming introduces write‐side delay primitives that allow the writer to pay most of the cost of synchronization between readers and writers. Only minimal synchronization overhead is placed on readers. Relativistic programming avoids unnecessarily strict ordering of read and write operations while still providing the capability to enforce linearizability. This paper shows how relativistic programming can be used to build a concurrent RBTree with synchronization‐free readers and both lock‐based and transactional memory‐based writers. Copyright © 2013 John Wiley & Sons, Ltd.     

高效液相色谱法测定母乳及牛乳中总核苷酸含量

建立高效液相色谱测定母乳和牛乳中总核苷酸含量和组成的分析方法。总核苷酸包括游离核苷酸、游离核苷、核苷聚合物及加合物等不同来源的可利用核苷总量。利用酶解法释放出母乳中的核苷,以硼化聚丙烯酰胺凝胶（Affi-Gel 601）作为固相萃取介质进行样品净化,用反相高效液相色谱仪检测,内标法定量,检测结果以核苷酸计。且针对母乳样品的特性,增加高温灭活步骤进行样品前处理,以检测母乳中核苷酸的天然含量及组成。对所建方法进行全面验证,结果表明其具有良好的线性,相关系数（r2）均在0.999以上;母乳中各核苷酸的检出限和定量限分别在0.18～0.45 mg/L和0.60～1.51 mg/L之间;母乳基质中3 种不同加标水平下总核苷酸的回收率均在99%～108%之间,连续3 d 6 次检测结果的相对标准偏差在0.8%～7.8%之间,显示了良好的准确性及精密度。然后进一步利用所建检测方法,评估母乳及5 种市面常见的牛乳中的核苷酸总量及组成用以验证该方法的适用性。该方法的灵敏度、准确性及精密度均可满足对母乳和牛乳样品中天然的核苷酸含量及组成的测定要求。本研究为今后大样本量调查母乳及牛乳样品中核苷酸的含量和组成提供了更加科学准确的方法。     

Charged nucleobases and their potential for RNA catalysis

Catalysis in living cells is carried out by both proteins and RNA. Protein enzymes have been known for over 200 years, but RNA enzymes, or "ribozymes", were discovered only 30 years ago. Developing insight into RNA enzyme mechanisms is invaluable for better understanding both extant biological catalysis as well as the primitive catalysis envisioned in an early RNA-catalyzed life. Natural ribozymes include large RNAs such as the group I and II introns; small RNAs such as the hepatitis delta virus and the hairpin, hammerhead, VS, and glmS ribozymes; and the RNA portion of the ribosome and spliceosome. RNA enzymes use many of the same catalytic strategies as protein enzymes, but do so with much simpler side chains. Among these strategies are metal ion, general acid-base, and electrostatic catalysis. In this Account, we examine evidence for participation of charged nucleobases in RNA catalysis. Our overall approach is to integrate direct measurements on catalytic RNAs with thermodynamic studies on oligonucleotide model systems. The charged amino acids make critical contributions to the mechanisms of nearly all protein enzymes. Ionized nucleobases should be critical for RNA catalysis as well. Indeed, charged nucleobases have been implicated in RNA catalysis as general acid-bases and oxyanion holes. We provide an overview of ribozyme studies involving nucleobase catalysis and the complications involved in developing these mechanisms. We also consider driving forces for perturbation of the pK(a) values of the bases. Mechanisms for pK(a) values shifting toward neutrality involve electrostatic stabilization and the addition of hydrogen bonding. Both mechanisms couple protonation with RNA folding, which we treat with a thermodynamic formalism and conceptual models. Furthermore, ribozyme reaction mechanisms can be multichannel, which demonstrates the versatility of ribozymes but makes analysis of experimental data challenging. We examine advances in measuring and analyzing perturbed pK(a) values in RNA. Raman crystallography and fluorescence spectroscopy have been especially important for pK(a) measurement. These methods reveal pK(a) values for the nucleobases A or C equal to or greater than neutrality, conferring potential histidine- and lysine/arginine-like behavior on them. Structural support for ionization of the nucleobases also exists: an analysis of RNA structures in the databases conducted herein suggests that charging of the bases is neither especially uncommon nor difficult to achieve under cellular conditions. Our major conclusions are that cationic and anionic charge states of the nucleobases occur in RNA enzymes and that these states make important catalytic contributions to ribozyme activity. We conclude by considering outstanding questions and possible experimental and theoretical approaches for further advances.     

VARIATIONS IN THE SOLVENT EXTRACTION BEHAVIOR OF BIFONCTIONAL PHOSPHORUS-BASED COMPOUNDS MODIFIED WITH TBP

ABSTRACT

The solvent extraction of americium from nitric acid by several modified bifunctional extractants in CCl₄has been investigated. For all the compounds examined, addition of a modifier such as tributylphosphate (TBP) enhances distribution ratios at high aqueous acidities. The effect of the modifier at lower acidities varies depending on the basicity of the bifunctional extractant. While the most basic extractants show significantly reduced distribution ratios from lower acid solutions upon TBP addition, for the less basic compounds only slight reductions or, in some cases, even moderate increases in extraction are observed. Studies of the effect of modifier basicity on extraction behavior have also been carried out. The changes in distribution ratios with modifiers fall within the range of variations observed for diluent effects with extractants of this type. Increases in high acid distribution ratios upon TBP addition to an extractant as simple as trioctylphosphine oxide indicate that this modification of extraction behavior may be of general use for a wide range of neutral extractants     

The Separation of Beryllium from Selected Elements Using the Dipex® Extraction Chromatographic Resin

Abstract

An extraction chromatographic resin containing the acidic chelating organophosphorus extractant, Dipex^®, sorbed onto an inert polymeric substrate has been evaluated for the separation of beryllium from a wide range of elements. The elements selected comprise those which can interfere with the determination of beryllium by inductively coupled plasma‐atomic emission spectroscopy (ICP‐AES) and matrix elements which commonly occur in environmental and industrial samples. Based on batch uptake measurements, a method that separates beryllium from all potential ICP‐AES spectral interfering elements using a single extraction chromatographic column is outlined. The chromatographic parameters of the separation method have been optimized using simulated samples generated using the digestion process employed in beryllium analyses by the Y‐12 National Security Complex and simulated ground water samples.