bluuebunny/crossref_metadata_2025 huggingface dataset:
Vegetable Oils in Lubrication
Authors: Biresaw Girma
Published: February 2020

Vegetable oils and their derivatives are commercially used in lubricant formulations as both base oils and additives. They are major players in the growing biobased lubricant market because they provide a wide range of benefits, including superior environmental and health properties. Vegetable oils are applied in lubrication in various forms. In the past, vegetable oils have been used directly as base oils in the presence of a variety of additives (e.g. antioxidants), or blended with petroleum base oils, such as polyalphaolefins, to enhance their performance. Vegetable oils are also used in lubrication after undergoing chemical, thermal, or enzymatic modifications to enhance their performance. Examples of such commercial products include epoxidized, heat‐bodied, and blown vegetable oils. More recently, vegetable oils are used to produce fatty acids (FAs) and fatty acid methyl esters (FAMEs), which are used in lubrication directly or after further modifications. Examples of such products include estolides, epoxidized FAMEs, and phosphonated FAMEs. In the latest applications, vegetable oils, their FAs, and FAMEs are used to produce base oils with renewable carbon via various biorefinery processes, where they are subjected to deoxygenation, isomerization, and other processes. These products have similar structures as petroleum‐based oils and can be used as “drop‐in” components to enhance the bio‐content of lubricants to meet regulatory and environmental requirements (e.g. BioPreferred), without affecting performance. Such application of vegetable oils has a significant market potential since petroleum‐based lubricant formulations are extremely affordable and account for >98% of the current global lubricant market.
Extrusion Processing of Oilseed Meals for Food and Feed Production
Authors: Riaz Mian N.
Published: February 2020

There are several different definitions of extrusion depending on the manufacturer as well as the purpose of the extrusion. For the purpose of this chapter, the best definition of extrusion can be explained as “continuous cooking under pressure, moisture and elevated temperature.” During the process of extrusion, several operations take place, such as grinding, hydration, mixing, shearing, thermal treatment, gelatinization, protein denaturation, destruction of micro‐organisms and some toxic compounds, shaping, expanding, and partial dehydration. The use of extruders has been expanding rapidly in the food, feed, and oilseed industries over the past few years, although basic extruder technology has been around for a long time. It has been used in one form or another in many industries. New designs of extrusion equipment have increased the range of their application in food, feed, and oilseed processing.
Modification of Fats and Oils via Chemical and Enzymatic Methods
Authors: Senanayake S.P.J. Namal , Shahidi Fereidoon
Published: February 2020

Hydrogenation, interesterification, fractionation, and blending are distinct processes that can be applied to modify the physical or chemical properties of fats and oils in order to improve their usefulness. These processes can be used alone or in combination with each other. By combining hydrogenation, fractionation, and interesterification with the simple blending of native and modified oils, it is possible to engineer a wide variety of fats and oils with characteristics suited to specific applications. Hydrogenation is used to convert liquid oils into products having different consistencies, melting points, and textures. On the other hand, interesterification produces changes in physical properties by rearrangement or redistribution of fatty acids within and among the triacylglycerols (TAGs) of oils. Fractionation provides a means of producing fats and oils with sharply defined melting characteristics.
Dietary Fat Substitutes
Authors: Shahidi Fereidoon , Peng Han , Senanayake Namal
Published: February 2020

Fat substitutes are becoming an important part of the North American diet. Many Americans are looking for ways to enjoy their favorite foods while maintaining a low‐calorie diet. Food scientists are developing new food constituents that will mimic the function of fats in foods while keeping the calorie contents of foods low. Dietary fat substitutes are food components able to replace, completely or partially, dietary fat in such a manner that certain physical and organoleptic properties of the food product involved are left unaltered as much as possible. There are two principal approaches to the replacement of dietary fat. The first involves hydratable carbohydrates and proteins with the mouthfeel of fats. The second includes nonabsorbable synthetic substances with the physical properties and technical function of fat within foods.
Lipid Oxidation: New Perspectives on an Old Reaction
Authors: Schaich Karen M.
Published: February 2020

After lying in the doldrums during the no/low fat era, lipid oxidation is once again attracting intense interest for its effects on food quality, stability of personal care products, impairment of functional properties, and nutrition in foods, as well as toxic potential in tissues. Advanced analytical methods now detect lipid oxidation products with greater sensitivity and in more molecular detail, which provides greater power in elucidating reactions. At the same time, the comparative timing for the development of various products as well as the distribution of products under different conditions cannot be explained by the traditional free radical chain reaction driven solely by hydrogen abstractions. The previous edition of this article provided arguments for considering a number of alternate reactions of peroxyl and alkoxyl radicals that compete with hydrogen abstraction and alter outcomes of lipid oxidation, and then integrated these alternate pathways into a coherent reaction scheme that shows there interdependence and interrelationships. This article builds on that base, provides evidence for epoxides a product equal to hydroperoxides in importance, and introduces thinking about pathway changes induced by solvents, oxidation catalysts, and other environmental conditions.
Rendering
Authors: Meeker David
Published: February 2020

Rendering recycles animal and poultry by‐products such as fat, bones, hide, offal, feathers, hoofs, horns, hair, and blood. The by‐products represent from 37% to 50% of the live weight of the various meat animals and as much as 57% of the live weight of many fish species. The current annual global production of meat and poultry is 325 million metric tons (MMT), and the resulting raw material for rendering would be 217 MMT per year if rendering was used everywhere. Rendered proteins and fats compete on the world commodity market with plant‐based products. Rendered protein products are primarily used in food for poultry, pigs, ruminants, pets, and fish. Fat products are used for animal food, oleochemicals, and biofuels. Rendering meat by‐products into animal food ingredients improves the sustainability of both the meat production industry and the users of the by‐products. Composting or anaerobic digestion of these by‐products is less environmentally impactful than landfills but results in more GHG production than feed ingredient use. Reducing food waste will improve global sustainability when otherwise wasted animal by‐products are put to the highest value use. The future of rendering will depend on the industry adapting to the ever‐changing environmental, social, health, and sustainability challenges.
Paints, Varnishes, and Related Products
Authors: Webster Dean C.
Published: February 2020

The paint and coatings industry is highly diverse and complex. Architectural coatings protect houses and buildings; product finishes are applied to furniture and fixtures, prefinished flooring and automobiles; special purpose coatings are used for things like pipelines, aircraft, and ships. Oleochemicals have been an important contributor to paint and coatings technology beginning centuries ago with the use of oils as a paint binder, then as oleoresinous varnishes and, in the recent century, as a key ingredient in alkyd resins – polyesters containing oils or fatty acids. A distinct property that unsaturated “drying oils” brings to paint and coatings systems is their ability to undergo autoxidation leading to the formation of a coherent and solid film. While technical developments in the past 100 years have led to advanced coatings resin technologies such as amino resins, acrylics, synthetic latexes, polyurethanes, and epoxy resins, alkyd resins continue to be the second most used resin technology due to their versatility, ease of synthesis and ease of use. By varying the composition and raw materials used, alkyds can be tailored for a broad range of applications. Alkyds can also be adapted to be used in high solids coatings as well as in waterborne systems. The volume of alkyd resins used worldwide is expected to grow over the next decade.
By‐Product Utilization
Authors: Pickard Mark D. , da Silva Lima Renan S. , Shahidi Fereidoon
Published: February 2020

This article provides an overview of the by‐products of seed processing and oil refining. The various uses of soybean, canola, sunflower, palm, safflower, cottonseed, olive, coconut, flax, and more are examined along with their extraction processes. The latest improvements in the by‐products of oil refining, such as lecithin, refining by‐product lipid, spent bleaching earth, deodorizer distillate, and spent catalyst are also reviewed.
Transgenic Oils
Authors: Durrett Timothy P.
Published: February 2020

Genetic engineering (GE) technology offers a powerful tool for developing a broad range of oils with specialized compositions useful for different food and industrial applications. Such oils could contain modified ratios of endogenous fatty acids, or even unusual fatty acids and lipids, produced through the transgenic expression of biosynthetic genes from other species. However, GE technology has mostly been limited to crop input traits such as herbicide tolerance and insect resistance. As this article will discuss, only recently have high oleic acid soybeans with transgenically modified oil compositions been grown on a commercial basis. For the most part, the synthesis of unusual fatty acids with useful functional groups only results in the accumulation of low levels of the desired product in the transgenic seed. The continually improving knowledge of fatty acid biosynthesis and triacylglycerol assembly in oilseeds will be explored. This knowledge, combined with new systems and synthetic biology approaches, promises to overcome biological bottlenecks limiting the production of unusual fatty acids in transgenic oilseeds. This article will also describe the regulatory and economic barriers that likely present significant barriers to the widespread adoption of novel oils with altered output traits. As discussed, new business models for the commercial production of specialized industrial oils will therefore need to be considered.
Edible Films and Coatings from Soybean and Other Protein Sources
Authors: Lim Loong‐Tak , Hettiarachchy Navam S. , Eswaranandam Satchithanandam
Published: February 2020

Proteins are abundant in nature and are highly functional. They can be converted into edible films and coating for food applications. The formation of protein films and coatings require a denaturation step to unfold the protein molecules and to promote intermolecular interactions via the formation of disulfide and hydrogen bonds, as well as hydrophobic interactions. Plasticizers, such as low‐molecular‐weight polyols and organic acids, are often added to the film‐forming formulations to impart flexibility essential for end‐use handling. By and large, edible films are produced by solvent casting. Solution properties (viscosity, surface tension, etc.) must be optimized in order to produce coherent film of consistent material properties. Alternatively, dry processing involves extrusion of proteins at elevated temperature (above glass transition) in the presence of small quantity of water and plasticizer. Material properties of protein films can be modified by incorporating additives, heat curing, and/or irradiation/chemical treatments to achieve optimal mechanical strength and extensibility essential for end‐use handling. Protein films and coatings are strong gas barriers when they are dry but exhibit poor moisture barrier properties due to their inherent hydrophilic nature. Edible films and coatings are versatile carriers for bioactives (e.g. antimicrobials, antioxidants, nutraceuticals, and micronutrients), flavors, colors, and other additives, making them a useful tool in product innovation.
Adulteration of Olive Oil
Authors: Mossoba Magdi , Srigley Cynthia , Karunathilaka Sanjeewa , Fardin‐Kia Ali R. , Ridge Clark , Hatzakis Emmanuel , Yakes Betsy
Published: February 2020

The US Food and Drug Administration (US FDA) is mandated with protection of the US public against intentional adulteration of foods for economically motivated gain and deceptive label declarations such as those found with adulterated extra virgin olive oil (EVOO). In April 2016, a US Congressional Committee expressed concerns related to reports of the high prevalence of imported olive oil sold in the United States that is adulterated or mislabeled. Such fraudulence reportedly includes the mixing of EVOO with seed oil, which could adversely impact the health of consumers who are allergic to seed oil. The most serious issue facing regulatory agencies has been the relative ease of adulterating EVOO while meeting the physical and chemical criteria of established trade standards, such as those of the International Olive Council (IOC) and the US Department of Agriculture (USDA). This issue underscores the urgent need for more rigorous and accurate analytical methodologies, including untargeted rapid screening tools, for detecting such fraudulence. This article presents an overview of current official methods, analytical procedures that target specific analytes, and rapid screening tools that rely on chemometric analysis.
Improving Oils and Oilseeds Through Crop Genetics
Authors: Knowlton Susan
Published: February 2020

Consumer preferences, labeling mandates, and dietary health concerns are driving changes to ingredient selection within the food industry. Many conventional oilseeds are being selected or genetically modified to improve the seed oil fatty acid composition ranging from raising/lowering saturates or unsaturates to incorporating new fatty acids abundant in other species. Most of these new oils have significant improvements over their commodity oil counterparts. This article reviews the most common and commercially viable new oilseed varieties providing trait‐modified oils developed within the last 10–15 years.
Basic Lipid Science
Authors: O'Keefe Sean , Ambigaipalan Priyatharini
Published: February 2020

The role of lipids in health and diseases has been of great interest to scientists for many years. Lipids are defined largely based on their solubility in organic solvents and insolubility in water but they have a wide range of structures and biological effects. Fatty acids can be differentiated by chain length (short chain, medium chain, and long chain), unsaturation (saturated, monounsaturated, and polyunsaturated), the position of double bonds (omega 3, omega 6), and geometry of double bonds (cisvstrans). Increased intake of saturated fatty acids, trans fatty acids, and cholesterol have been shown to associate with coronary heart diseases. In this article, these factors in relation to health and diseases are discussed.
Dietary Lipids and Physiological Function
Authors: Kitts David D.
Published: February 2020

The association between dietary fat intake and chronic disease has been researched for more than 60 years. Cardiovascular disease (CVD) continues to be a leading cause of global mortality, accounting for 17.3 million deaths in 2013, equivalent to 31.5% of total deaths. One out of every three deaths in the United States is attributed to heart disease, stroke, or other forms of CVD; an estimated average of one death every second and more than 330 billion dollars in health expenditures and lost productivity. Moreover, the incidence of obesity has doubled from 1980 to 2015 in more than 40 countries and is associated with chronic diseases such as cardiovascular (atherosclerosis) and type 2 diabetes. Selecting diets that provide energy from monounsaturated and polyunsaturated fats are also beneficial to consumer health. Fats and oils are the source of many nonesterified fatty acids that act as signaling molecules to regulate gene expression that controls body homeostasis, including lipid metabolism. This article describes how dietary fats and oils, and related derived products are involved in chemical and biochemical mechanisms that define the safety and toxicity of dietary lipid consumption.
Lipids and Cardiovascular Health
Authors: Shahidi Fereidoon
Published: February 2020

Lipids have been associated with heart health, thus it is of interest to continue exploring their effects. Lipids consist of different fatty acids belonging to the saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) types. Depending on their structures, these have different effects on the heart health. Therefore, it is important to understand their effect and devise strategies to improve heart health based on the latest available scientific knowledge. However, it remains a challenge to critically evaluate the existing literature in order to better inform and educate the general public who lack any in‐depth background of the topic. Thus, this article provides introductory level of beneficial as well as potentially adverse effect of fatty acids on heart health.
Lipids and Cancer
Authors: Surh Young‐Joon , Kim Do‐Hee , Jang Jeong‐Hoon , Na Hye‐Kyung
Published: February 2020

Lipids play important roles in maintaining membrane integrity and fluidity. Lipids, especially in the form of free fatty acids, are main sources of energy supply. Rapidly proliferating cancer cells have high avidity for energy, and this is met through elevated
de novo
synthesis of fatty acids that generate ATP during β‐oxidation process. It is evident that neoplastic tissues often exhibit aberrant activation of lipogenesis. Tumors reprogram signaling pathways via multiple mechanisms in the direction to meet the bioenergetic and biosynthetic demands. Now tumor‐associated reprogramming of lipid metabolism is recognized as one of the hallmarks of cancer. Some bioactive lipid metabolites, if produced in excess, influence the earlier stage of multistep carcinogenesis by damaging DNA or stimulating the mutated cells to premalignant ones during tumor promotion. Over the past decade, targeting aberrant lipid metabolism has become a promising anticancer or chemopreventive strategy.
Calorie‐Reduced Lipids and Health
Authors: Shahidi Fereidoon , Van Nguyen Lanh
Published: February 2020

Dietary low‐calorie structured lipids have been recognized as contributory factors in the development and prevention of many diseases such as obesity, cardiovascular diseases, diabetes, hypertension, and other chronic disorders. Experimental studies have been conducted in both animals and humans to evaluate the potential role of low‐calorie lipids in disease risk reduction. This article explains the main calorie‐reduced lipids, their physiological functions, and molecular actions on health.
Lipids in the Treatment of Neurodegenerative Diseases
Authors: Lange Klaus W.
Published: February 2020

The brain contains high concentrations of lipids, and lipid homoeostasis is fundamental to the maintenance of brain health. Alterations of the main lipid classes have been shown to be involved in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). Dietary omega‐3 polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA), can have favorable effects on brain structure and cognitive functions and might be a useful strategy in the prevention of AD. However, further randomized controlled trials are required before omega‐3 PUFAs can be recommended as a preventive measure for mild cognitive impairment and dementia. Omega‐3 PUFAs may also have therapeutic potential in Parkinson's and Huntington's diseases. PUFAs can exert anti‐inflammatory effects that may be relevant to multiple sclerosis (MS). However, controlled studies regarding the potential benefits of PUFA supplementation in MS have shown inconclusive results. To determine whether omega‐3 PUFAs can provide neuroprotective effects in neurodegenerative diseases, biological markers for an early identification of individuals at risk need to be found. Furthermore, the demonstration of neuroprotective efficacy in clinical studies is a significant challenge.
Lipids in the Treatment of Mental Disorders
Authors: Lange Klaus W.
Published: February 2020

The management of mental disorders is dominated today by pharmacotherapy, while nutrition and dietary approaches play a minor role. Evidence from both preclinical and clinical investigations suggests an important role for lipids in major mental disorders. Alterations in the concentration, organization, and metabolism of lipids are associated with mood disorders, schizophrenia, and behavioral problems in childhood. The lipid composition of the brain can be influenced by nutrition, environmental factors, and behavioral activity. Lipids, and omega‐3 polyunsaturated fatty acids (PUFAs) in particular, may represent a target for the prevention and treatment of mental disorders. Deficits in the dietary omega‐3 PUFAs, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been implicated in the pathophysiology of several mental disorders and linked to the maintenance of brain health. This may be mediated by the modulation of inflammatory processes and direct effects on neuronal membrane fluidity and receptor function. Low levels of omega‐3 PUFAs have been associated with various mental disorders, such as poor cognition, depression, anxiety disorders, schizophrenia, and attention‐deficit/hyperactivity disorder (ADHD). The available findings from randomized clinical trials examining the therapeutic efficacy of omega‐3 PUFAs are inconsistent and inconclusive. This limits their usage in psychiatric practice. Future research should investigate the molecular mechanisms underlying the effects of omega‐3 PUFAs in mental disorders. Large‐scale, well‐designed clinical trials should be conducted to assess the efficacy of omega‐3 PUFAs in the prevention and therapy of various mental disorders.
Dynamic gating window technique for the reduction of dosimetric error in respiratory‐gated spot‐scanning particle therapy: An initial phantom study using patient tumor trajectory data
Authors: Miyamoto Naoki , Yokokawa Kouhei , Takao Seishin , Matsuura Taeko , Tanaka Sodai , Shimizu Shinichi , Shirato Hiroki , Umegaki Kikuo
Published: February 2020

Spot‐scanning particle therapy possesses advantages, such as high conformity to the target and efficient energy utilization compared with those of the passive scattering irradiation technique. However, this irradiation technique is sensitive to target motion. In the current clinical situation, some motion management techniques, such as respiratory‐gated irradiation, which uses an external or internal surrogate, have been clinically applied. In surrogate‐based gating, the size of the gating window is fixed during the treatment in the current treatment system. In this study, we propose a dynamic gating window technique, which optimizes the size of gating window for each spot by considering a possible dosimetric error. The effectiveness of the dynamic gating window technique was evaluated by simulating irradiation using a moving target in a water phantom. In dosimetric characteristics comparison, the dynamic gating window technique exhibited better performance in all evaluation volumes with different effective depths compared with that of the fixed gate approach. The variation of dosimetric characteristics according to the target depth was small in dynamic gate compared to fixed gate. These results suggest that the dynamic gating window technique can maintain an acceptable dose distribution regardless of the target depth. The overall gating efficiency of the dynamic gate was approximately equal or greater than that of the fixed gating window. In dynamic gate, as the target depth becomes shallower, the gating efficiency will be reduced, although dosimetric characteristics will be maintained regardless of the target depth. The results of this study suggest that the proposed gating technique may potentially improve the dose distribution. However, additional evaluations should be undertaken in the future to determine clinical applicability by assuming the specifications of the treatment system and clinical situation.
The number of fillers may not matter as long as they all match the description: The effect of simultaneous lineup size on eyewitness identification
Authors: Wooten Alex R. , Carlson Curt A. , Lockamyeir Robert F. , Carlson Maria A. , Jones Alyssa R. , Dias Jennifer L. , Hemby Jacob A.
Published: February 2020

According to the Diagnostic Feature‐Detection (DFD) hypothesis, the presence of fillers that match the eyewitness's description of the perpetrator will boost discriminability beyond a showup, and very few fillers may suffice to produce the advantage. We tested this hypothesis by comparing showups with simultaneous lineups of size 3, 6, 9, and 12. Participants (N = 10,433) were randomly assigned to one of these conditions, as well as target‐present (TP) versus target‐absent (TA) lineup. As predicted by the DFD hypothesis, lineups were superior to showups, and there was no advantage with increased lineup size beyond a 3‐member lineup. The confidence‐accuracy (CA) relationship held a similar pattern. The only effect of increased lineup size was a lower likelihood of choosing a suspect (guilty or innocent). We conclude that police should focus more on the quality rather than quantity of fillers.
A Glial‐Silicon Nanowire Electrode Junction Enabling Differentiation and Noninvasive Recording of Slow Oscillations from Primary Astrocytes
Authors: Saracino Emanuela , Maiolo Luca , Polese Davide , Semprini M. , Borrachero‐Conejo Ana Isabel , Gasparetto Jacopo , Murtagh Stefano , Sola Margherita , Tomasi Lorenzo , Valle Francesco , Pazzini Luca , Formaggio Francesco , Chiappalone Michela , Hussain Saber , Caprini Marco , Muccini Michele , Ambrosio Luigi , Fortunato Guglielmo , Zamboni Roberto , Convertino Annalisa , Benfenati Valentina
Published: February 2020

The correct human brain function is dependent on the activity of non‐neuronal cells called astrocytes. The bioelectrical properties of astrocytes in vitro do not closely resemble those displayed in vivo and the former are incapable of generating action potential; thus, reliable approaches in vitro for noninvasive electrophysiological recording of astrocytes remain challenging for biomedical engineering. Here it is found that primary astrocytes grown on a device formed by a forest of randomly oriented gold coated‐silicon nanowires, resembling the complex structural and functional phenotype expressed by astrocytes in vivo. The device enables noninvasive extracellular recording of the slow‐frequency oscillations generated by differentiated astrocytes, while flat electrodes failed on recording signals from undifferentiated cells. Pathophysiological concentrations of extracellular potassium, occurring during epilepsy and spreading depression, modulate the power of slow oscillations generated by astrocytes. A reliable approach to study the role of astrocytes function in brain physiology and pathologies is presented.
Cooperatively pursuing a target unmanned aerial vehicle by multiple unmanned aerial vehicles based on multiagent reinforcement learning
Authors: Wang Xiaoqiang , Xuan Shuzhe , Ke Liangjun
Published: February 2020

This article considers a pursuit‐evasion problem, in which multiple unmanned aerial vehicles (multi‐UAVs) are required to cooperatively pursue a moving target UAV. The dynamics of the three‐dimensional partially unknown environment makes it hard to deal with this problem. A multiagent reinforcement learning approach is proposed. This algorithm is extended from cooperative double Q‐learning by taking into account of the characteristics of the studied pursuit problem. To study the performance, a simulator is developed, which concerns the dynamic nature of the environment and flight constraints of UAV. Compared with several state‐of‐the‐art reinforcement learning algorithms, the proposed algorithm provides better policy such that the pursuing multi‐UAVs can effectively chase the moving target UAV.
Shape Memory Materials Database Tool—A Compendium of Functional Data for Shape Memory Materials
Authors: Benafan Othmane , Bigelow Glen S. , Young Avery W.
Published: February 2020

A database tool is developed for archiving and exploring shape memory materials including shape memory alloys (SMAs), superelastic alloys, magnetic SMAs, shape memory polymers, and shape memory ceramics. Over 750 000 data points and their pedigree metadata are extracted and stored into records. Data are handled via a graphical user interface running in a web application. The tool provides interactive menus for the selection of material types, properties, and filters, culminating with a visualization panel. Data are displayed in three forms, consisting of pie charts, 2D scatter plots, and ternary diagrams, all of which provide unique information pertinent to the materials and properties being explored. This database tool is a major stepping stone toward building an information system where an entire continuum of material novices to experts can have an infrastructure to explore and discover these multifunctional materials.
Designer Biomaterials to Model Cancer Cell Invasion In Vitro: Predictive Tools or Just Pretty Pictures?
Authors: Bahlmann Laura C. , Smith Laura J. , Shoichet Molly S.
Published: February 2020

Metastasis is the leading cause of mortality in cancer patients. Underlying this process is the invasion and colonization of cancer cells into healthy tissues. Engineered hydrogel models of tumor microenvironments present an opportunity to understand the microenvironmental determinants of cellular invasion. The biochemical and mechanical cues, presented in the form of adhesion sites, degradable cues, matrix stiffness, and architecture, have significant effects on the extent of cancer cell migration, and the mechanisms employed by these cells to move through their matrix. Coculture with stromal cells such as cancer associated fibroblasts, endothelial cells, and immune cells that are associated with poor prognosis demonstrate that these cells exacerbate cancer cell invasion. With these models, researchers aim not only to recapitulate known cancer cell behaviors in a dish, but also to uncover new insights into mechanisms underlying these phenomena, paving the way for novel treatment strategies. In this perspective, the design of engineered models that are used to study cancer cell invasion and metastasis in vitro is discussed. To this end, the authors seek to understand and put into perspective: do these models reveal relevant mechanisms of cancer cell migration, or are they simply pretty pictures with little biological translatability?
Tailoring Multilevel‐Stable Remanence States in Exchange‐Biased System through Spin‐Orbit Torque
Authors: Yun Jijun , Bai Qiaoning , Yan Ze , Chang Meixia , Mao Jian , Zuo Yalu , Yang Dezheng , Xi Li , Xue Desheng
Published: February 2020

Multilevel remanence states have potential applications in ultra‐high‐density storage and neuromorphic computing. Continuous tailoring of the multilevel remanence states by spin‐orbit torque (SOT) is reported in perpendicularly magnetized Pt/Co/IrMn heterostructures. Double‐biased hysteresis loops with only one remanence state can be tuned from the positively or negatively single‐biased loops by SOT controlled sign of the exchange‐bias field. The remanence states associated with the heights of the sub‐loops are continually changed by tuning the ratio of the positively and negatively oriented ferromagnetic domains. The multilevel storage cells are demonstrated by reading the remanent Hall resistance through changing the sign and/or the magnitude of current pulse. The synaptic plasticity behaviors for neuromorphic computing are also simulated by varying the remanent Hall resistance under the consecutive current pulses. This work demonstrates that SOT is an effective method to tailor the remanence states in the double‐biased heavy metal/ferromagnetic/antiferromagnetic system. The multilevel‐stable remanence states driven by SOT show potential applications in future multilevel memories and neuromorphic computing devices.
Earnings, Wages, and Poverty Outcomes of US Farm and Low‐Skill Workers
Authors: Barham Bradford L. , Melo Ana P. , Hertz Thomas
Published: February 2020

The American Community Survey supports rich comparisons of welfare outcomes across low‐skill workers, including the native‐born and immigrants, in farm and nonfarm occupations. Evidence from 2016–17 suggests that farm and nonfarm labor markets are integrated, especially for immigrants. Although US‐born workers typically earn higher wages than immigrants, in some occupations, immigrants have higher wages and/or earnings. Immigrant farmworkers receive somewhat lower wages than citizens do but work more hours and generate similar earnings. Household poverty rates are above the national average for an array of low‐skill workers, especially among immigrants. The most substantial welfare difference is in health insurance access, where coverage is much higher for US‐born workers. Labor market and social policy implications of these findings are explored.
Farmer cooperation in agro‐clusters: Evidence from Indonesia
Authors: Wardhana Dadan , Ihle Rico , Heijman Wim
Published: February 2020

Collective action in geographically concentrated farming regions can lead to improvements in farmer income. We model farmer cooperation inside such agro‐clusters as a two‐stage decision process. From 1,151 completely filled‐in questionnaires, we find that being located in an agro‐cluster increases farmers' likelihood to cooperate as well as enhances their income. Farmers' attitude towards cooperation is positively influenced by being male, having more assets, and operating a larger farm, but negatively affected if the farmer reports that her household is food vulnerable. The number of hours worked by farmers on the farm and the frequency of face‐to‐face meetings also raise the probability of engaging in cooperation. A higher density of agro‐clusters, higher crop diversity and being located farther away from urban centers are found to increase on average the income level of a farmer. Hence, the promotion of agro‐clusters also in rural regions remains a promising initiative for increasing farmer income.
Neoadjuvant treatment for resectable pancreatic adenocarcinoma: What is the best protocol?
Authors: Motoi Fuyuhiko , Unno Michiaki
Published: February 2020

Although upfront surgery has been the gold standard for pancreatic adenocarcinoma that is planned for resection, it should be compared with the alternative strategy of neoadjuvant therapy. Despite the many reports of the efficacy of neoadjuvant therapy, most of them were not comparative. Recently Prep‐02/JSAP05 study clearly demonstrated the significant survival benefit of neoadjuvant chemotherapy over upfront surgery for pancreatic adenocarcinoma that is planned for resection. These findings opened a new chapter of neoadjuvant therapy. Ongoing trials are expected to confirm the evidence. This review summarizes the past, present, and future perspectives of neoadjuvant therapy and its optimization.
Ecological niche differences between two polyploid cytotypes ofSaxifraga rosacea
Authors: Decanter Lucile , Colling Guy , Elvinger Nora , Heiðmarsson Starri , Matthies Diethart
Published: February 2020

Premise

Different cytotypes of a species may differ in their morphology, phenology, physiology, and their tolerance of extreme environments. We studied the ecological niches of two subspecies ofSaxifraga rosaceawith different ploidy levels: the hexaploid Central European endemic subspeciessponhemicaand the more widely distributed octoploid subspeciesrosacea.

Methods

For both cytotypes, we recorded local environmental conditions and mean plant trait values in populations across their areas of distribution, analyzed their distributions by niche modeling, studied their performance at two transplant sites with contrasting conditions, and experimentally tested their cold resistance.

Results

Mean annual temperature was higher in hexaploid than in octoploid populations and experiments indicated that frost tolerance of the hexaploid is lower than that of the octoploid. Reproduction of octoploids from Central Europe was higher than that of hexaploids at a transplant site in subarctic Iceland, whereas the opposite was true in temperate Luxembourg, indicating adaptation of the octoploids to colder conditions. Temperature variables were also most important in niche models predicting the distribution of the two cytotypes. Genetic differences in survival among populations were larger for the octoploids than for the hexaploids in both field gardens, suggesting that greater genetic variability may contribute to the octoploid's larger distributional range.

Conclusions

Our results support the hypotheses that different cytotypes may have different niches leading to spatial segregation, and that higher ploidy levels can result in a broader ecological niche and greater tolerance of more extreme conditions.
BN‐Embedded Polycyclic Aromatic Hydrocarbon Oligomers: Synthesis, Aromaticity, and Reactivity
Authors: Chen Yijing , Chen Weinan , Qiao Yanjun , Lu Xuefeng , Zhou Gang
Published: February 2020

BN‐embedded oligomers with different pairs of BN units were synthesized by electrophilic borylation. Up to four pairs of BN units were incorporated in the large polycyclic aromatic hydrocarbons (PAHs). Their geometric, photophysical, electrochemical, and Lewis acidic properties were investigated by X‐ray crystallography, optical spectroscopy, and cyclic voltammetry. The B−N bonds show delocalized double‐bond characteristics and the conjugation can be extended through the trans‐orientated aromatic azaborine units. Calculations reveal the relatively lower aromaticity for the inner azaborine rings in the BN‐embedded PAH oligomers. The frontier orbitals of the longer oligomers are delocalized over the inner aromatic rings. Consequently, the inner moieties of the BN‐embedded PAH oligomers are more active than the outer parts. This is confirmed by a simple oxidation reaction, which has significant effects on the aromaticity and the intramolecular charge‐transfer interactions.
Regioselective Arene C−H Alkylation Enabled by Organic Photoredox Catalysis
Authors: Holmberg‐Douglas Natalie , Onuska Nicholas P. R. , Nicewicz David A.
Published: February 2020

Expanding the toolbox of C−H functionalization reactions applicable to the late‐stage modification of complex molecules is of interest in medicinal chemistry, wherein the preparation of structural variants of known pharmacophores is a key strategy for drug development. One manifold for the functionalization of aromatic molecules utilizes diazo compounds and a transition‐metal catalyst to generate a metallocarbene species, which is capable of direct insertion into an aromatic C−H bond. However, these high‐energy intermediates can often require directing groups or a large excess of substrate to achieve efficient and selective reactivity. Herein, we report that arene cation radicals generated by organic photoredox catalysis engage in formal C−H functionalization reactions with diazoacetate derivatives, furnishing sp2–sp3 coupled products with moderate‐to‐good regioselectivity. In contrast to previous methods utilizing metallocarbene intermediates, this transformation does not proceed via a carbene intermediate, nor does it require the presence of a transition‐metal catalyst.
Chiral Aluminum Complex Controls Enantioselective Nickel‐Catalyzed Synthesis of Indenes: C−CN Bond Activation
Authors: Zhang Tao , Luan Yu‐Xin , Zheng Su‐Juan , Peng Qian , Ye Mengchun
Published: February 2020

A chiral aluminum complex controlled, enantioselective nickel‐catalyzed domino reaction of aryl nitriles and alkynes proceeding by C−CN bond activation was developed. The reaction provides various indenes, bearing chiral all‐carbon quaternary centers, under mild reaction conditions in yields of 32 to 91 % and ee values within the 73–98 % range. The reaction mechanism and aspects of stereocontrol were investigated by DFT calculations.
Light‐Induced Chiral Iron Copper Selenide Nanoparticles Prevent β‐Amyloidopathy In Vivo
Authors: Zhang Hongyu , Hao Changlong , Qu Aihua , Sun Maozhong , Xu Liguang , Xu Chuanlai , Kuang Hua
Published: February 2020

The accumulation and deposition of β‐amyloid (Aβ) plaques in the brain is considered a potential pathogenic mechanism underlying Alzheimer's disease (AD). Chiral l/d‐FexCuySe nanoparticles (NPs) were fabricated that interfer with the self‐assembly of Aβ42 monomers and trigger the Aβ42 fibrils in dense structures to become looser monomers under 808 nm near‐infrared (NIR) illumination. d‐FexCuySe NPs have a much higher affinity for Aβ42 fibrils than l‐FexCuySe NPs and chiral Cu2−xSe NPs. The chiral FexCuySe NPs also generate more reactive oxygen species (ROS) than chiral Cu2−xSe NPs under NIR‐light irradiation. In living MN9D cells, d‐NPs attenuate the adhesion of Aβ42 to membranes and neuron loss after NIR treatment within 10 min without the photothermal effect. In‐vivo experiments showed that d‐FexCuySe NPs provide an efficient protection against neuronal damage induced by the deposition of Aβ42 and alleviate symptoms in a mouse model of AD, leading to the recovery of cognitive competence.
Chemo‐ and Magnetotaxis of Self‐Propelled Light‐Emitting Chemo‐electronic Swimmers
Authors: Salinas Gerardo , Dauphin Alice L. , Colin Camille , Villani Elena , Arbault Stéphane , Bouffier Laurent , Kuhn Alexander
Published: February 2020

Miniaturized autonomous chemo‐electronic swimmers, based on the coupling of spontaneous oxidation and reduction reactions at the two poles of light‐emitting diodes (LEDs), are presented as chemotactic and magnetotactic devices. In homogeneous aqueous media, random motion caused by a bubble‐induced propulsion mechanism is observed. However, in an inhomogeneous environment, the self‐propelled devices exhibit positive chemotactic behavior, propelling themselves along a pH or ionic strength gradient (∇pH and ∇I, respectively) in order to reach a thermodynamically higher active state. In addition, the intrinsic permanent magnetic moment of the LED allows self‐orientation in the terrestrial magnetic field or following other external magnetic perturbations, which enables a directional motion control coupled with light emission. The interplay between chemotaxis and magnetotaxis allows fine‐tuning of the dynamic behavior of these swimmers.
Reaction Mechanisms of Layered Lithium‐Rich Cathode Materials for High‐Energy Lithium‐Ion Batteries
Authors: Zhao Shuoqing , Yan Kang , Zhang Jinqiang , Sun Bing , Wang Guoxiu
Published: February 2020

Layered lithium‐rich cathode materials have attracted extensive interest owing to their high theoretical specific capacity (320–350 mA h g−1). However, poor cycling stability and sluggish reaction kinetics inhibit their practical applications. After many years of quiescence, interest in layered lithium‐rich cathode materials is expected to revive in answer to our increasing dependence on high‐energy‐density lithium‐ion batteries. Herein, we review recent research progress and in‐depth descriptions of the structure characterization and reaction mechanisms of layered lithium‐rich manganese‐based cathode materials. In particular, we comprehensively summarize the proposed reaction mechanisms of both the cationic redox reaction of transition‐metal ions and the anionic redox reaction of oxygen species. Finally, we discuss opportunities and challenges facing the future development of lithium‐rich cathode materials for next‐generation lithium‐ion batteries.
Total Synthesis of a Mycolic Acid from Mycobacterium tuberculosis
Authors: Tahiri Nabil , Fodran Peter , Jayaraman Dhineshkumar , Buter Jeffrey , Witte Martin D. , Ocampo Tonatiuh A. , Moody D. Branch , Van Rhijn Ildiko , Minnaard Adriaan J.
Published: February 2020

In Mycobacterium tuberculosis, mycolic acids and their glycerol, glucose, and trehalose esters (“cord factor”) form the main part of the mycomembrane. Despite their first isolation almost a century ago, full stereochemical evaluation is lacking, as is a scalable synthesis required for accurate immunological, including vaccination, studies. Herein, we report an efficient, convergent, gram‐scale synthesis of four stereo‐isomers of a mycolic acid and its glucose ester. Binding to the antigen presenting protein CD1b and T cell activation studies are used to confirm the antigenicity of the synthetic material. The absolute stereochemistry of the syn‐methoxy methyl moiety in natural material is evaluated by comparing its optical rotation with that of synthetic material.
Environment‐friendly synthesis of sustainable chitosan‐based nonisocyanate polyurethane: A biobased polymeric film
Authors: Das Munmi , Mandal Bishnupada , Katiyar Vimal
Published: February 2020

Sustainable, biobased nonisocyanate polyurethane (NIPU) films having excellent water absorption characteristics were synthesized by a green‐chemistry approach, eliminating the use of any toxic component. An environment‐friendly bulk polyaddition reaction was carried out between a natural amine‐containing polysaccharide, chitosan, and carbonated soybean oil (CSBO) to prepare the NIPUs. Epoxidized soybean oil was reacted with carbon dioxide to obtain CSBO and the conversion was confirmed by Fourier transform infra‐red and 1H nuclear magnetic resonance spectroscopies. NIPUs synthesized via this method did not involve the use of any curing agent and the crosslinking density of the polymer could be varied by altering the amine content. NIPUs with higher chitosan content showed better thermal and chemical properties, and superior water absorption characteristics. FTIR studies confirmed the typical linkages of polyurethane and the swelling behavior justified its enhanced resistance to organic solvents. Karl Fischer titration study proved the excellent water‐absorption capacity by absorbing ~90% moisture from toluene. These properties enable NIPUs to have diverse probable applications in the fields of chemical‐resistant coating, sealant, and also as an inorganic plant growth substrate because of its high water holding capacity.
Recent Advances in the Application of Selectfluor as a “Fluorine‐free” Functional Reagent in Organic Synthesis
Authors: Yang Ke , Song Mengjie , Ali Ahmed I. M. , Mudassir Syed M. , Ge Haibo
Published: February 2020

Selectfluor, [1‐chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo‐[2.2.2]octane bis(tetrafluoroborate)], is not only an important electrophilic fluorinating agent but also a facile and efficient “fluorine‐free” functional reagent in other organic reactions. In this Minireview, we will present a brief history of Selectfluor as a transition metal oxidant, fluorine cation and radical initiator in “fluorine‐free” functionalizations over the last five years.