bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved theoretical minimum of the specific on-resistance of a superjunction
Authors: Akshay K , Karmalkar Shreepad
Published: November 2020

We derive simple closed-form solutions for the optimum pillar parameters—length L
opt, width 2W
opt and doping N
opt of a superjunction. The parameters yield the minimum specific on-resistance, R
ONSP, for a target breakdown voltage, V
BR,target, thereby solving a long standing design problem. The minimum R
ONSP occurs for zero charge imbalance. Our estimates of N
opt are higher and hence the R
ONSP lower than in prior works by >30%. We show that, N
opt depends on W
opt alone, since for this doping, the p and n pillars are just fully depleted when the reverse bias equals the V
BR of the one-dimensional p+n junction. Further, our derivation reveals that L
opt depends on V
BR,target alone since the field distribution associated with V
BR,target is approximately uniform over L
opt. In contrast, prior design solutions require numerical or iterative calculations, and are either physically opaque or give a distorted insight that L
opt depends on W
opt and N
opt on L
opt. Moreover, our solutions have a generic form that permits quick calculations across different materials. They are validated by technology computer-aided design simulation for low and wide band gap materials—Si and 4H-SiC. Their results for GaN and diamond are given to reveal the wide 100 V–30 kV application range of devices in these materials. The solutions are also used to reveal the scope for reducing the R
ONSP of several fabricated devices reported in literature by process improvement.
Effect of laser linewidth on the tunable diode laser absorption spectroscopy system
Authors: Rui Zhang , Fang Wang , Yan Wang , Bo Yan , Hong-Fei Guo , Feng-Jiang Xi , Xin-Bo Li
Published: November 2020

In this paper, a theoretical investigation of the influence of laser linewidth on the tunable diode laser absorption spectroscopy system is presented. The theoretical analysis and formula discussion of laser line shape are carried out by frequency noise spectrum density. Taking Lorentz line shape of laser line width as an example, the interaction principle of laser line width and gas absorption spectral line is analyzed. The relation curve of laser linewidth and maximum amplitude is simulated by MATLAB platform with self-defined simulation parameters. These results can provide theoretical basis for guiding the selection of laser and gas absorption spectral line and improving the detection accuracy of gas concentration.
A survey on deep learning-based non-invasive brain signals: recent advances and new frontiers
Authors: Zhang Xiang , Yao Lina , Wang Xianzhi , Monaghan Jessica , McAlpine David , Zhang Yu
Published: November 2020

Brain signals refer to the biometric information collected from the human brain. The research on brain signals aims to discover the underlying neurological or physical status of the individuals by signal decoding. The emerging deep learning techniques have improved the study of brain signals significantly in recent years. In this work, we first present a taxonomy of non-invasive brain signals and the basics of deep learning algorithms. Then, we provide the frontiers of applying deep learning for non-invasive brain signals analysis, by summarizing a large number of recent publications. Moreover, upon the deep learning-powered brain signal studies, we report the potential real-world applications which benefit not only disabled people but also normal individuals. Finally, we discuss the opening challenges and future directions.
Waste expectations of fusion steels under current waste repository criteria
Authors: Bailey G.W. , Vilkhivskaya O.V. , Gilbert M.R.
Published: November 2020

During operation fusion reactor components will be exposed to long periods of neutron irradiation. As such, a reactor’s structural steels will become activated and need to be disposed of as radioactive waste. Previous studies have shown that such wastes can struggle to meet low level waste (LLW) requirements meaning that costly geological disposal may be required. In order to explore the waste expectations of steels from European DEMO-like fusion reactors, several radioactive waste management systems have been investigated. This includes their LLW criteria, currently available disposal sites and planned future developments. This information was used to analyse the results of DEMO-like inventory simulations of potential reactor steels. The simulations were performed with the inventory code FISPACT-II and the TENDL2017 nuclear data library. The results suggest that when steels are exposed to near plasma neutron fluxes they will struggle to meet the majority of LLW requirements. For lower neutron fluxes, typical of reactor containment vessels, the waste expectations can be more positive, with several steels able to meet some low level criteria. It can be concluded that steels should not be expected to be consistently internationally classified as LLW 100 years after reactor shut down. As all activated fusion waste cannot be disposed of in a single location, it is recommended that waste disposal strategies are included in any fusion reactor proposal before construction begins. These strategies need to align with the radioactive waste regulations the proposed reactor will be subject to.
External RMP effect on locked-mode-like instability in helical plasmas
Authors: Takemura Y. , Watanabe K.Y. , Sakakibara S. , Ohdachi S. , Narushima Y. , Ida K. , Yoshinuma M.
Published: November 2020

The slowing-down mechanism of the locked-mode-like instabilities with and without an island structure is investigated through the effects of an external RMP (resonant magnetic perturbation) on the instabilities. For both instabilities, the slowing-down duration decreases with the increase in the external RMP, and the RMP dependence is consistent with the braking model of the j × B force due to the interaction between the instabilities and the external RMP. Moreover, the relationship between the amplitude and the frequency of both locked-mode-like instabilities during the slowing down is consistent with the force balance model between the j × B force due to the external RMP and a viscous force. These results suggest that the slowing down of both locked-mode-like instabilities with finite external RMP occurs due to the j × B force driven by the external RMP.
Research on the Negative Resistance Characteristics of Silicon-based Trench MOS Barrier Schottky Diodes
Authors: Chen Huanwen , Wang Yijun , Zhang Hang
Published: November 2020

The negative resistance characteristics of Trench MOS Barrier Schottky (TMBS) diodes were studied by simulation and theoretical calculation. A reasonable simulation model was established according to the experimental results of Schottky Barrier Diodes (SBD), which were utilized to simulate the TMBS diodes. A theoretical calculation model of TMBS diodes under forward bias was constructed based on existing SBD theoretical analysis to systematically understand the simulation results. Both simulation and theoretical calculation demonstrate that the negative resistance characteristics of TMBS diodes under forward bias are caused by the accumulation of minority carriers at the epitaxial region and the accumulation of majority carriers at the epitaxial region and oxide layer.
Lattice Boltzmann Simulation of the Growth and Departure of Vapor Bubble in Flow Boiling
Authors: Guan Geng , Shan Xiaopeng , Nie Deming
Published: November 2020

In this work the liquid-vapor transition in flow boiling was numerically studied through a two-phase lattice Boltzmann method (LBM). The benchmark test of the nucleate boiling with a single nucleate site was adopted to validate our computational code. Then the focus moves to the behavior of the bubble growth and departure induced by a heated plate in shear flow. The effects of the shear flow were examined by varying its magnitude. In addition, the wettability of the heated plate was also taken into account. It has been shown that the shear flow has negligible effect on the period of bubble release for the neutral and hydrophilic surfaces, which, however, is not the case for the hydrophobic surface.
Influences Analysis of Seismic Intensity on Dynamic Response of Slope Supported by Frame Structure with Pre-stressed Anchors
Authors: Wang Jun , Ye Shuaihua
Published: November 2020

The mountainous area is wide in the western region of China, and there are many seismic zones. Due to the two factors, there are more and more slope projects in the western region, and the influence of earthquake also need to be considered into the relevant researches on anchored slope. The damage to the slope under the earthquake has attracted the attention of researchers, Therefore, there are many studies on slope support under the seismic action. However, there is little research on the influence of seismic intensity on the slopes supported with pre-stressed anchored-frame structures. This paper based on an engineering example in the northwest loess area, taking into account the synergy of the frame-anchor-soil, a three-dimensional finite element model of the slope system with pre-stressed anchored-frame structure under the seismic action was established. The dynamic response of the supported slope was calculated by the finite element software ADINA, and the impact of different seismic intensities on the slope displacement, acceleration, axial force of anchor, and earth pressure are analyzed
Effect of the Rotor Blades Part Span Shrouds on the Transonic Axial Compressor Operation Map
Authors: Sebelev A.A. , Schengals A.A. , Aleksenskiy V.A. , Tamm A. Yu. , Klyavin O.I.
Published: November 2020

The paper presents the results of the investigation of the part span shroud effect on the transonic axial compressor operational map. The objective of the paper is a 4.5-stage transonic low-pressure compressor of the aero-derivative gas turbine engine. The study was performed with using 3D RANS calculations via Ansys CFX commercial solver. The numerical model was validated with experimental data for 4 speedlines. The standard k-ɛ turbulence model demonstrated good agreement with the experimental data while SST model unexpectedly overpredicted mass flow rate. The strong effect of the mesh aspect ratio in the radial direction was observed. A significant decrease of the mass flow rate and the compressor efficiency was shown for the rotation speed range 85% – 95%. The maximum mass flow rate decreasing was estimated as 3.5%, maximum efficiency deterioration – 1.5%.
The Boundedness of the Solution of a Class of Biological Population Models
Authors: Zhao Jing , Kong Xiangming , Wang Chunxiao
Published: November 2020

In biological models, the equilibrium solution is a bounded positive solution, which has very important practical significance. In this paper, a class of nonlinear delay difference equations is proposed, which is applicable to a variety of common biological population models, such as Nicholson’s blowflies and hematopoietic stem cell models. This article is to discuss this kind of nonlinear delay difference equation boundedness of the solution of the equilibrium, in the existing literature, this paper studies the nonlinear delay difference equation of the existence of bounded positive solutions of thought method, using structure function method and reduction to absurdity proved the existence of positive solutions of the equation, a class of nonlinear delay difference equation is obtained sufficient conditions for the existence of bounded positive solutions of, and proof is given. It is proved that the equilibrium solution of the nonlinear delay difference equation is always a bounded positive solution if the function f(x) is monotonically decreasing function or unimodal function and the function g(x) is monotonically increasing function. The relevant results of the existing literature are generalized and improved to make the results more general.
Optimal Design of Sound Insulation Frequency Band of Local Resonance Membrane Material
Authors: Zhang Jian , Zhou Qizheng , Wang Deshi , Gao Shengyao
Published: November 2020

In order to broaden the sound insulation frequency band of local resonance membrane materials, established an acoustic-vibration coupling model of multilayer membrane materials, based on the derived analytical solutions of the coupling equations. Simulate the sound insulation performance of the designed single-layer membrane materials with four different mass structures. Then combine different membrane materials to analyse the changes in the sound insulation frequency band. Calculations proves that: (1) The four single-layer membrane structures have a maximum TL peak of 40.08dB and the frequency of the smallest TL peak is at 204.56Hz in the frequency range of 100-1000Hz.(2) Combination of two same structures will significantly increase the sound insulation at the sound insulation peak;(3) The combination of single-layer membrane with different structures can broaden the sound insulation frequency band and enhance the sound insulation performance.
Evolutionary Game Analysis of Supervisory Decision Behavior of Third-party Trading Platform
Authors: Yang Yanbing , Zhang Qin
Published: November 2020

This paper constructs an asymmetric evolutionary game model between the “government-platform-consumer” three parties, uses Jacobian matrix and Lyapunov’s first method to analyze its replication dynamic equation, and discusses the influence of the main parameters on the agent’s decision-making behavior. Then, MATLAB simulation was used to demonstrate the gradual trend in different situations, with a view to providing a decision-making reference for the benign development of the third-party trading platform.
Option Pricing with Transaction Costs under the Subdiffusive Mixed Fractional Brownian Motion
Authors: Miao Jie
Published: November 2020

This paper probes into the issue of option pricing with transaction costs under the subdiffusive mixed fractional Brownian motion. Under reasonable economic assumptions, and by applying the strategy of the mean-self-financing delta hedging in the discrete-time setting, the generalized European call option pricing formula is further developed to capture the certain property of financial time series and better observe the law of finance market.
Soil carbon sequestration simulated in CMIP6-LUMIP models: implications for climatic mitigation
Authors: Ito Akihiko , Hajima Tomohiro , Lawrence David M , Brovkin Victor , Delire Christine , Guenet Bertrand , Jones Chris D , Malyshev Sergey , Materia Stefano , McDermid Sonali P , Peano Daniele , Pongratz Julia , Robertson Eddy , Shevliakova Elena , Vuichard Nicolas , Wårlind David , Wiltshire Andy , Ziehn Tilo
Published: November 2020

Land-use change affects both the quality and quantity of soil organic carbon (SOC) and leads to changes in ecosystem functions such as productivity and environmental regulation. Future changes in SOC are, however, highly uncertain owing to its heterogeneity and complexity. In this study, we analyzed the outputs of simulations of SOC stock by Earth system models (ESMs), most of which are participants in the Land-Use Model Intercomparison Project. Using a common protocol and the same forcing data, the ESMs simulated SOC distribution patterns and their changes during historical (1850–2014) and future (2015–2100) periods. Total SOC stock increased in many simulations over the historical period (30 ± 67 Pg C) and under future climate and land-use conditions (48 ± 32 Pg C for ssp126 and 49 ± 58 Pg C for ssp370). Land-use experiments indicated that changes in SOC attributable to land-use scenarios were modest at the global scale, in comparison with climatic and rising CO2 impacts, but they were notable in several regions. Future net soil carbon sequestration rates estimated by the ESMs were roughly 0.4‰ yr−1 (0.6 Pg C yr−1). Although there were considerable inter-model differences, the rates are still remarkable in terms of their potential for mitigation of global warming. The disparate results among ESMs imply that key parameters that control processes such as SOC residence time need to be better constrained and that more comprehensive representation of land management impacts on soils remain critical for understanding the long-term potential of soils to sequester carbon.
Legacy effects of cemeteries on groundwater quality and nitrate loads to a headwater stream
Authors: Lautz Laura K , Ledford Sarah H , Beltran Julio
Published: November 2020

Residential development and urbanization have increased nutrient loads to streams and groundwater through increased use of fertilizers and discharge of wastewater effluent. Stream degradation in urbanizing areas has simultaneously reduced natural attenuation of nutrients. In this context, cemeteries are an often-overlooked land use that may contribute to nutrient loading in urbanizing watersheds. Although cemeteries provide ecosystem services, such as infiltration of stormwater, micrometeorology control, and greenspace, they also pose a unique threat to groundwater quality due to degradation and leaching of organic material. To assess the potential legacy impact of cemeteries on water quality, we explored the impact of a large cemetery that comprises 9% of the total area of a suburban watershed on groundwater nitrate concentrations and stream nitrate loads. We found nitrate concentrations were significantly higher in cemetery groundwater (median = 6.2 mg l−1) than in residential groundwater (median = 0.05 mg l−1). During summer months (June through September), the stream is consistently a gaining stream receiving groundwater discharge. During this time, stream nitrate concentrations increase by 1.4–1.9 mg l−1 between the upstream edge of the cemetery and the downstream edge (from 0.03–0.46 mg l−1 to 1.6 mg l−1–2.1 mg l−1, respectively). Stream nitrate loads observed at gauging stations located about 500 m upstream and downstream of the cemetery property show that the stream nitrate load is consistently 20–40 kg NO3
−/day higher downstream of the cemetery between June to September. Given that the cemetery handles about 350–500 burials per year, it is estimated that 25%–50% of the nitrate load between the gauging stations could be attributable to groundwater discharge of burial decay products. Our observations of nitrate concentrations in cemetery groundwater, coupled with the increases in nitrate loads in a stream traversing the cemetery property, suggest cemeteries may be an overlooked source of nutrient loading in developed watersheds.
A uniformly fine-grained Mg-Y-Nd-Zr magnesium alloy with simultaneously optimized strength and ductility processed by forging and ECAP
Authors: Sun Yidan , Li Wei , Shi Xiaofang , Tian Liang
Published: November 2020

In this work, as-cast rare earth Mg-2Y-0.6Nd-0.5Zr alloy was successfully processed by forging at 350 °C and different numbers of passes of equal channel angular pressing (ECAP) along the Bc route. The effects of ECAP on the microstructure, texture and mechanical properties of a pre-forged Mg-2Y-0.6Nd-0.5Zr alloy were systematically investigated in this paper. The grain size of the alloy was refined from 140 μm to 1.9 μm by forging + ECAP. The alloy has obtained a uniform and fine microstructure under the action of dynamic recrystallization (DRX) during the ECAP process. The forged sample exhibited a strong basal texture. However, the alloy that was processed with ECAP had a tilted texture; the basal orientation was weakened, and the cylindrical and pyramidal orientation was enhanced. An analysis of the mechanical properties showed that the alloy exhibited favorable tensile strength and elongation of 262 MPa and 22.4% after forging and 4 passes of ECAP, which were increased by 118% and 113% compared with the as-cast sample. The alloy strength decreased slightly due to textural transformation and a high degree of recrystallization during ECAP, while the plasticity of the alloy that underwent 6 ECAP passes increased to 25.2%. The results show that the combination processing of forging and ECAP provides a new approach for optimizing the mechanical properties of magnesium alloys.
Whole-Genome Resequencing Reveals Adaptation Prior to the Divergence of Buffalo Subspecies
Authors: Rafiepour Mostafa , Ebrahimie Esmaeil , Vahidi Mohammad Farhad , Salekdeh Ghasem Hosseini , Niazi Ali , Dadpasand Mohammad , Liang Dong , Si Jingfang , Ding Xiangdong , Han Jianlin , Zhang Yi , Qanbari Saber
Published: November 2020

The application of high-throughput genotyping or sequencing data helps us to understand the genomic response to natural and artificial selection. In this study, we scanned the genomes of five indigenous buffalo populations belong to three recognized breeds, adapted to different geographical and agro-ecological zones in Iran, to unravel the extent of genomic diversity and to localize genomic regions and genes underwent past selection. A total of 46 river buffalo whole genomes, from West and East Azerbaijan, Gilan, Mazandaran, and Khuzestan provinces, were resequenced. Our sequencing data reached to a coverage above 99% of the river buffalo reference genome and an average read depth around 9.2× per sample. We identified 20.55 million SNPs, including 63,097 missense, 707 stop-gain, and 159 stop-loss mutations that might have functional consequences. Genomic diversity analyses showed modest structuring among Iranian buffalo populations following frequent gene flow or admixture in the recent past. Evidence of positive selection was investigated using both differentiation (Fst) and fixation (Pi) metrics. Analysis of fixation revealed three genomic regions in all three breeds with aberrant polymorphism contents on BBU2, 20, and 21. Fixation signal on BBU2 overlapped with the OCA2-HERC2 genes, suggestive of adaptation to UV exposure through pigmentation mechanism. Further validation using resequencing data from other five bovine species as well as the Axiom Buffalo Genotyping Array 90K data of river and swamp buffaloes indicated that these fixation signals persisted across river and swamp buffaloes and extended to taurine cattle, implying an ancient evolutionary event occurred before the speciation of buffalo and taurine cattle. These results contributed to our understanding of major genetic switches that took place during the evolution of modern buffaloes.
Firewood Transport as a Vector of Forest Pest Dispersal in North America: A Scoping Review
Authors: Solano Angelica , Rodriguez Shari L , Greenwood Leigh , Dodds Kevin J , Coyle David R
Published: November 2020

Native and nonnative insects and diseases can result in detrimental impacts to trees and forests, including the loss of economic resources and ecosystem services. Increases in globalization and changing human behaviors have created new anthropogenic pathways for long distance pest dispersal. In North America, literature suggests that once a forest or tree pest is established, the movement of firewood by the general public for recreational or home heating purposes is one of the primary pathways for its dispersal. Understanding human perceptions and behaviors is essential to inform the most effective strategies for modifying firewood and pest dispersal by humans. This scoping review seeks to assess trends and gaps in the existing literature, as well as patterns in behavior related to forest pest dispersal through firewood movement in North America. We identified 76 documents that addressed this topic to which we applied inclusion and exclusion criteria to select articles for further analysis. Twenty-five articles met the inclusion criteria and were categorized based on five identified themes: 1) insect incidence in firewood, 2) insect dispersal via firewood, 3) recreational firewood movement, 4) firewood treatments, and 5) behavior and rule compliance. The selected articles show trends that suggest that firewood movement presents a risk for forest insect dispersal, but that behavior can be modified, and compliance, monitoring, and treatments should be strengthened. This scoping review found limited research about western United States, Mexico, and Canada, various insect species and other organisms, regulation and management, awareness, and behavioral dimensions of firewood movement.
A minimally invasive periacetabular osteotomy technique: minimizing intraoperative risks
Authors: Thiagarajah Shankar , Bingham Joshua S , Grammatopoulos George , Witt Johan
Published: November 2020

The periacetabular osteotomy (PAO) is an extensive surgical procedure associated with potential risk to the adjacent neurovascular structures. A steep learning curve exists, with surgeon experience an important factor in outcome. Little detail exists of the osteotomies themselves, and how to make them safe and reproducible. This article describes our PAO technique with emphasis on specific safety steps. When performing the posterior column cut, migration of the osteotome beyond the lateral pelvis may lead to damage of the sciatic nerve. The safety features detailed include novel measurement of the posterior column width and the use of specific-width osteotomes to complete this osteotomy. To plan the cut, several computerized tomography-based measurements are taken starting just above the greater sciatic notch and continuing down to the inferior part of the acetabulum. The angle of this cut is determined by acetabular morphology and the width of the posterior column. These posterior column width measurements will determine the width of the osteotomes used to perform the cut with little risk that an osteotome will penetrate too far on the lateral side of the pelvis. To ensure the lateral cortex has been cut completely proximally, an osteotome with pre-measured depths may be used from a medial to a direct lateral trajectory. The senior author has been performing this modified approach since 2010 (n = 530 PAOs) and has witnessed no vascular injuries and no nerve injuries aside from minor lateral femoral cutaneous nerve issues. Utilization of these techniques has prevented any major nerve injury without the need for intraoperative electromyography.
First Report of a Gall Midge Species (Diptera: Cecidomyiidae) Associated With Pistachios
Authors: Sirjani Farshid O , Lewis Edwin E
Published: November 2020

A new dipterous pest is reported, for the first time, on commercial pistachios from Sirjan, Kerman province, Iran. The genus of the insect was determined to be Resseliella Seitner (Diptera: Cecidomyiidae). Adults are light brown to brown in color and 0.8–1.5 mm in length with females, generally, slightly larger than males. Females have an elongated ovipositor, which is characteristic of the genus. Larvae are orange in color, 2–3 mm in length in the later instars, feed under bark without inducing galls, and cause branch dieback on trees of various ages. Brown to black discolorations are observed on plant tissues under bark where the larvae feed. Infestations observed on current and the previous—year’s growths, ranged from 0.5 to 1.2 cm in diameter, and all located in outer branches. Dry leaves and fruit clusters on infested branches remain attached, which may be used to recognize infestation by the gall midge. Dark-colored, sunken spots with splits on the bark located at the base of the wilted sections of the shoots also are symptoms of Resseliella sp. larval activity. Species-level identification of the gall midge is currently underway.
Antecedents and Effects of Parasocial Relationships: A Meta-Analysis
Authors: Tukachinsky Riva , Walter Nathan , Saucier Camille J
Published: November 2020

The current meta-analysis synthesizes four decades of research (k = 120) on the antecedents and effects of parasocial relationships (PSRs). In line with contemporary theorization of PSRs as an extension of, rather than as a substitution for social relationships, the meta-analysis does not find a significant relationship between social deficiencies and PSRs. PSRs are also strongly correlated with factors that facilitate interpersonal bonds (e.g., homophily), other forms of involvement (e.g., identification, transportation), and persuasive outcomes. Furthermore, the analysis validates the theoretical distinction between PSRs and parasocial interactions (PSIs) revealing only a moderate correlation between the two constructs. Likewise, while PSRs and PSIs did not differ with respect to effects on persuasive outcomes, PSRs emerge as a stronger predictor of media involvement. The findings are discussed in relation to theoretical models of media involvement and effects
Adding the Capacity for an Intensive Care Unit Dedicated to COVID 19, Preserving the Operational Capability of a French Golden Hour Offset Surgical Team in Sahel
Authors: de Lesquen Henri , Bergez Marie , Vuong Antoine , Boufime-Jonqheere Alexandre , de l’Escalopier Nicolas
Published: November 2020

Introduction

In April 2020, the military medical planning needs to be recalibrated to support the COVID-19 crisis during a large-scale combat operation carried out by the French army in Sahel.

Material and Methods

Since 2019, proper positioning of Forward Surgical Teams (FSTs) has been imperative in peer-to-near-peer conflict and led to the development of a far-forward surgical asset: The Golden Hour Offset Surgical Team (GHOST). Dedicated to damage control surgery close to combat, GHOST made the FST aero-mobile again, with a light logistical footprint and a fast setting. On 19 and 25 March 2020, Niger and Mali confirmed their first COVID-19 cases, respectively. The pandemic was ongoing in Sahel, where 5,100 French soldiers were deployed in the Barkhane Operation.

Results

For the first time, the FST had to provide, continuously, both COVID critical care and surgical support to the ongoing operation in Liptako. Its deployment on a Main Operating Base had to be rethought on Niamey, to face the COVID crisis and support ongoing operations. This far-forward surgical asset, embedded with a doctrinal Role-1, sat up a 4-bed COVID intensive care unit while maintaining a casualty surgical care capacity. A COVID training package has been developed to prepare the FST for this innovative employment. This far-forward surgical asset was designed to support a COVID-19 intensive care unit before evacuation, preserving forward surgical capability for battalion combat teams.

Conclusion

Far-forward surgical assets like GHOST have demonstrated their mobility and effectiveness in a casualty care system and could be adapted as critical care facilities to respond to the COVID crisis in wartime.
Tobacco Imagery in the 20 Best-Selling Video Games of 2018
Authors: Forsyth Susan R , McDaniel Patricia A
Published: November 2020

Introduction

Video games are played by the majority of American adolescents. A small body of research has shown that video games expose users to tobacco imagery, potentially influencing subsequent smoking behavior. We examine the presence, type, and quantity of tobacco imagery in recent popular video games.

Methods

After identifying 20 best-selling US video games of 2018 and selecting each YouTube video of all cut scenes and bridging game play, we coded each video for the presence of five types of tobacco imagery. We also recorded the length of time tobacco content was visible during the video.

Results

Seven of the top 20 video games contained tobacco imagery, which comprised between 7 seconds and 38 minutes of game play. All five types of tobacco imagery were accounted for: visible tobacco paraphernalia, tobacco products used to further game play, background characters using tobacco products, and main characters (playable and nonplayble) using tobacco products. Visible tobacco paraphernalia was the most common type of tobacco imagery and included both real and fictionalized tobacco brands that sometimes drew on real cigarette brand imagery. Three games allowed players to control tobacco-using characters.

Conclusions

Popular video games continue to expose players to tobacco imagery. Because video games are played repeatedly, the potential exists for adolescents to experience even more tobacco imagery than the baseline exposure established here, further increasing the potential for harm. Existing voluntary and regulatory approaches to policing tobacco content are inadequate; thus, policymakers should consider further interventions to minimize tobacco content in video games.

Implications

Video games, popular among youth and young adults, are known to contain tobacco imagery. Less is known about the quantity and type of this imagery among recent popular games. We found that 7 of the 20 best-selling video games of 2018 in the United States contained a variety of tobacco imagery and exposed players to as much as 38 minutes of tobacco content. Given the established link between exposure to tobacco marketing in media such as films and subsequent smoking behavior, policies to minimize tobacco imagery in video games that exceed the scant protections offered by the Master Settlement Agreement could help reduce smoking prevalence among youth.
Opioids: God’s Own Medicine
Authors: Winter Jerrold
Published: November 2020

Albert Schweitzer called pain “a more terrible lord of mankind than even death.” Thus, it is not surprising that humans have from the earliest times attempted to identify plants which might provide pain relief. The Odyssey by Homer provides a mythic account of the use of one such agent… . Then Helen, daughter of Zeus, took other counsel. Straightaway she cast into the wine of which they were drinking a drug to quit all pain and strife, and bring forgetfulness of every ill. Whoso should drink this down, when it is mingled in the bowl, would not in the course of that day let a tear fall down over his cheeks, no, not though his mother and father should lie there dead … Such cunning drugs had the daughter of Zeus, drugs of healing, which Polydamna, the wife of Thor, had given her, a woman of Egypt, for there the earth, the giver of grain, bears the greatest store of drugs … … More than a century ago, it was suggested by Oswald Schmiedeberg, a German scientist regarded by many as the father of modern pharmacology, that the drug to which Homer refers is opium for “no other natural product on the whole earth calls forth in man such a psychical blunting as the one described.” When today, in the fields of Afghanistan or Turkey or India, the seed capsule of the opium poppy, Papaver somniferum, is pierced, a milky fluid oozes from it which, when dried, is opium. Virginia Berridge, in her elegant history of opium in England, tells us that the effects of opium on the human mind have probably been known for about 6,000 years and that opium had an honored place in Greek, Roman, and Arabic medicine. I will not dwell on that ancient history but will instead jump ahead to the 17th century by which time opium had gained wide use in European medicine.
Mendeleev’s Periodic Classification and Law in French Chemistry Textbooks
Authors: Vincent Bernadette Bensaude , Belmar Antonio García
Published: November 2020

The most striking feature of the diffusion of Mendeleev’s system in France is that his great achievement prompted no real debates, no controversy among French academic chemists. It is not that his work was totally ignored. Rather, it was integrated as a non-event in the daily work focused on the discovery and characterization of chemical elements thanks to new techniques (spectroscopy, crystallization, and so on). In science journals Mendeleev’s system attracted attention only insofar as it could lead to the discovery of new chemical elements. After briefly mentioning when and how Mendeleev’s ideas were presented in French primary, secondary, and higher education chemistry textbooks and mentioned in official programs, we will try to understand the reasons for preferring alternative criteria for classification in chemistry textbooks. In addition to the explicit arguments advanced by those who mentioned Mendeleev’s proposals, we will attempt to interpret the silence that most textbook authors kept. In a third section, we will symmetrically focus on the small group of chemists who promoted Mendeleev’s periodic classification and try to disentangle their motivations and modes of appropriation. We will then conclude that, far from being a form of resistance to Mendeleev’s specific system, the overall skepticism expressed in French chemistry textbooks was the expression of an enduring statu quo resulting from a long debate over the best chemical classification in educational milieus. In September 1879 the Department of Haute-Marne organized at the Hôtel de la Préfecture de Chaumont an exposition scolaire aimed at exhibiting the innovative activities developed by teachers and students of local primary school institutions. It was intended to contribute to the reform of primary education following the trauma caused by the defeat in the war against Prussia. As one of its organizers claimed, “it is primary instruction, and its patriotic direction, which made the strength of our enemies. It should make ours.” It was in this context of educational reform and post-war tensions that we found the first reference to didactic use of Mendeleev’s periodic system in France.
Functional Group Interconversion
Authors: Lambert Tristan H.
Published: November 2020

Chaozhong Li of the Shanghai Institute of Organic Chemistry reported (J. Am. Chem. Soc. 2012, 134, 10401) the silver nitrate catalyzed decarboxylative fluorination of carboxylic acids, which shows interesting chemoselectivity in substrates such as 1. A related decarboxylative chlorination was also reported by Li (J. Am. Chem. Soc. 2012, 134, 4258). Masahito Ochiai at the University of Tokushima has developed (Chem. Commun. 2012, 48, 982) an iodobenzene-catalyzed Hofmann rearrangement (e.g., 3 to 4) that proceeds via hypervalent iodine intermediates. The dehydrating agent T3P (propylphosphonic anhydride), an increasingly popular reagent for acylation chemistry, has been used (Tetrahedron Lett. 2012, 53, 1406) by Vommina Sureshbabu at Bangalore University to convert amino or peptide acids such as 5 to the corresponding thioacids with sodium sulfide. Jianqing Li and co-workers at Bristol-Myers Squibb have shown (Org. Lett. 2012, 14, 214) that trimethylaluminum, which has long been known to effect the direct amidation of esters, can also achieve the direct coupling of acids and amines, such as in the preparation of amide 8. The propensity of severely hindered 2,2,6,6-tetramethylpiperidine (TMP) amides such as 9 to undergo solvolysis at room temperature has been shown (Angew. Chem. Int. Ed. 2012, 51, 548) by Guy Lloyd-Jones and Kevin Booker-Milburn at the University of Bristol. The reaction proceeds by way of the ketene and is enabled by sterically induced destabilization of the usual conformation that allows conjugation of the nitrogen lone pair with the carbonyl. Matthias Beller at Universität Rostock has found (Angew. Chem. Int. Ed. 2012, 51, 3905) that primary amides may be transamidated via copper(II) catalysis. The conditions are mild enough that an epimerization-prone amide such as 11 undergoes no observable racemization during conversion to amide 13. A photochemical transamidation has been achieved (Chem. Sci. 2012, 3, 405) by Christian Bochet at the University of Fribourg that utilizes 385-nm light to activate a dinitroindoline amide in the presence of amines such as 15, which produces the amide 16. Notably, photochemical cleavage of the Ddz protecting group occurs at a shorter wavelength of 300 nm.
Functional Group Reduction
Authors: Lambert Tristan H.
Published: November 2020

The reduction of azobenzene 1 with catalyst 2 was reported (J. Am. Chem. Soc. 2012, 134, 11330) by Alexander T. Radosevich at Pennsylvania State University, representing a unique example of a nontransition metal-based two-electron redox catalysis platform. Wolfgang Kroutil at the University of Graz found (Angew. Chem. Int. Ed. 2012, 51, 6713) that diketone 4 was converted to piperidinium 5 with very high stereoselectivity using a transaminase followed by reduction over Pd/C. Dennis P. Curran at the University of Pittsburgh reported (Org. Lett. 2012, 14, 4540) that NHC-borane 7 is a convenient reducing agent for aldehydes and ketones, showing selectivity for the former as in the monoreduction of 6 to 8. A catalytic reduction of esters to ethers with Fe3(CO)12 and TMDS, as in the conversion of 9 to 10, was developed (Chem. Commun. 2012, 48, 10742) by Matthias Beller at the Leibniz-Institute for Catalysis. Meanwhile, iridium catalysis was used (Angew. Chem. Int. Ed. 2012, 51, 9422) by Maurice Brookhart at the University of North Carolina at Chapel Hill for the reduction of esters to aldehydes with diethylsilane (e.g., 11 to 12). As an impressive example of selective reduction, Ohyun Kwon at UCLA reported (Org. Lett. 2012, 14, 4634) the conversion of ester 13 to aldehyde 14, leaving the malonate moiety intact. The cobalt complex 16 was found (Angew. Chem. Int. Ed. 2012, 51, 12102) by Susan K. Hanson at Los Alamos National Laboratory to be an effective catalyst for C=O, C=N, and C=C bond hydrogenation, including the conversion of alkene 15 to 17. The use of frustrated Lewis pair catalysis for the low-temperature hydrogenation of alkenes such as 18 was developed (Angew. Chem. Int. Ed. 2012, 51, 10164) by Stefan Grimme at the University of Bonn and Jan Paradies the Karlsruhe Institute of Technology. Guanidinium nitrate was found (Chem. Commun. 2012, 48, 6583) by Kandikere Ramaiah Prabhu at the Indian Institute of Science to catalyze the hydrazine-based reduction of alkenes such as 20. The hydrogenation of thiophenes is difficult for a number of reasons, but now Frank Glorius at the University of Münster has developed (J. Am. Chem. Soc. 2012, 134, 15241) an effective system for the highly enantioselective catalytic hydrogenation of thiophenes and benzothiophenes, including 22.
Development of Flow Reactions
Authors: Taber Douglass F.
Published: November 2020

For a review of a monograph by C. Wiles and P. Watts on applications of flow reactors in organic synthesis, see Org. Process. Res. Dev. 2011, 15, 947. For a review by Klavs S. Jensen of MIT of flow approaches, see Angew. Chem. Int. Ed. 2011, 50, 7502. Hans-René Bjørsvik of the University of Bergen described (Org. Process. Res. Dev. 2011, 15, 997) a multijet oscillating disc microreactor, and Andreas Schmid of the Technische Universität Dortmund (Adv. Synth. Catal. 2011, 353, 2511) and László Poppe of the Budapest University of Technology and Economics discussed (Adv. Synth. Catal. 2011, 353, 2481) continuous flow reactors for biotransformations. Gases are readily handled in a flow apparatus. S. Chandrasekhar of the Indian Institute of Chemical Technology, Hyderabad demonstrated (Tetrahedron Lett. 2011, 52, 3865) partial deuteration of 1 to 2, using D2O as the deuterium source. Peter H. Seeberger of the Max Planck Institute, Potsdam oxidized (Org. Lett. 2011, 13, 5008) 3 to 4 with singlet oxygen. Dong-Pyo Kim of Chungnam National University and Robert H. Grubbs of Caltech effected (Org. Lett. 2011, 13, 2398) ethenolysis of 5 to give 6 and 7. Takashi Takahashi of the Tokyo Institute of Technology showed (Chem. Commun. 2011, 47, 12661) that even phosgene could be handled in a flow system, using it to activate 8 for condensation with benzylamine to give 9. In the liquid phase, Stephen L. Buchwald of MIT prepared (Angew. Chem. Int. Ed. 2011, 50, 8900) 11 by the fluorination of 10. Jesús Alcázar of Janssen Pharmaceutical, Toledo, showed (Tetrahedron Lett. 2011, 52, 6058) that a nitrile 12 could be reduced in a flow system to the aldehyde 13. Mark York of CSIRO prepared (Tetrahedron Lett. 2011, 52, 6267) the furan 16 by condensation of 14 with 15. Floris P.J.T. Rutjes of Radboud University Nijmegen used (Org. Process Res. Dev. 2011, 15, 783) the careful controls of a flow reactor to optimize the exothermic combination of 17 with 18 to give 19. Professor Buchwald demonstrated (Angew. Chem. Int. Ed. 2011, 50, 10665) a flow protocol for the lithiation of 20 with in situ borylation and Pd-catalyzed coupling with 21 to give 22.
Natural Product Synthesis by C–H Functionalization: (±)-Allokainic Acid (Wee), (–)-Cameroonan-7α-ol (Taber), (+)-Lithospermic Acid (Yu), (–)-Manabacanine (Kroutil), Streptorubin B, and Metacycloprodigiosin (Challis)
Authors: Taber Douglass F.
Published: November 2020

Andrew G.H. Wee of the University of Regina showed (Org. Lett. 2010, 12, 5386) that with the bulky BTMSM group on N and the electron-withdrawing pivaloyloxy group deactivating the alternative C–H insertion site, the diazo ketone 1 cleanly cyclized to 2, with 21:1 diastereocontrol. Oxidative cleavage of the arene followed by amide reduction and methylenation of the ketone converted 2 into (±)-allokainic acid 3. Intermolecular C–H insertion was the key step in a complementary route to (±)-kainic acid reported (Org. Lett. 2011, 13, 2674) by Takehiko Yoshimitsu of Osaka University. Rh-mediated intramolecular C–H insertion was also the first step in our (J. Org. Chem. 2011, 76, 1874) synthesis of (–)-cameroonan-7α-ol 6. In the course of that synthesis, seven of the C–H bonds of 4 were converted to C–C bonds. Jin-Quan Yu of Scripps/La Jolla oxidatively activated (J. Am. Chem. Soc. 2011, 133, 5767) the ortho H of 8 with catalytic Pd, then engaged that intermediate with 7 in a Heck coupling, to give 9, and thus (+)-lithospermic acid 10. The starting acid 8 was prepared by enantioselective Rh-mediated intramolecular C–H insertion. Wolfgang Kroutil of the University of Graz found (Angew. Chem. Int. Ed. 2011, 50, 1068) that berberine bridging enzyme (BBE) from the California poppy could be used preparatively to cyclize a variety of tetrahydroisoquinolines, including 11 to give (–)-manibacanine 13. Although this is clearly a Mannich-type cyclization, a simple Mannich reaction gave a 40:60 mixture of regioisomers, each of them racemic. The enzyme effected cyclization to a 96:4 ratio of regioisomers, and only one enantiomer of 11 participated. Gregory L. Challis of the University of Warwick harnessed (Nature Chem. 2011, 3, 388) the [2Fe-2S] Rieske cluster enzyme RedG of Streptomyces coelicolor to effect oxidative cyclization of 14 to streptorubin B 15. An ortholog of the enzyme cyclized 14 to metacycloprodigiosin 16. It is interesting to speculate as to whether the cyclizations are initiated by the activation of an H on the alkyl sidechain or by oxidation of the pyrrole.