Particulate organonitrates are formed from volatile organic compounds (VOCs) oxidation by radicals. A portion of semi-volatile gas-phase organonitrates can be incorporate into aerosol by oxidation reactions or portioning, and has been an important component of secondary organic aerosol (SOA). Particulate organonitrates study has become one of the important aspects of atmospheric chemistry. Given the large number and variability of chemical constituents, and possible chemical transformations of organonitrates, such characterization presents a key problem for research. Based on recent research progress on particulate organonitrates, this paper summarizes the formation mechanism and quantification method of particulate organonitrates. Profiting from the application of high time resolution techniques, field measurements has become the major approach of particulate organonitrates study. Thermal dissociation-laser induced fluorescence (TD-LIF) and aerosol mass spectrometers (AMS) have been used to quantify and provide the evolution processes of particulate organonirates. Meanwhile, chemical ionization mass spectrometer(CIMS)allows for the determination of molecular ion composition of organonitrates, promising to become the important direction of study of particulate organonirates in future field measurements. To have a deep insight on precursor and atmospheric chemistry processes of particulate organonirates, future research should focus on the combination of field measurement, modeling simulation and laboratory simulation, and these will also lead to a more comprehensive understanding of formation mechanism of particulate organonirates
Particulate organonitrates are formed from volatile organic compounds (VOCs) oxidation by radicals. A portion of semi-volatile gas-phase organonitrates can be incorporate into aerosol by oxidation reactions or portioning, and has been an important component of secondary organic aerosol (SOA). Particulate organonitrates study has become one of the important aspects of atmospheric chemistry. Given the large number and variability of chemical constituents, and possible chemical transformations of organonitrates, such characterization presents a key problem for research. Based on recent research progress on particulate organonitrates, this paper summarizes the formation mechanism and quantification method of particulate organonitrates. Profiting from the application of high time resolution techniques, field measurements has become the major approach of particulate organonitrates study. Thermal dissociation-laser induced fluorescence (TD-LIF) and aerosol mass spectrometers (AMS) have been used to quantify and provide the evolution processes of particulate organonirates. Meanwhile, chemical ionization mass spectrometer(CIMS)allows for the determination of molecular ion composition of organonitrates, promising to become the important direction of study of particulate organonirates in future field measurements. To have a deep insight on precursor and atmospheric chemistry processes of particulate organonirates, future research should focus on the combination of field measurement, modeling simulation and laboratory simulation, and these will also lead to a more comprehensive understanding of formation mechanism of particulate organonirates
Analyzing how climate change affects vegetation distribution is one of the central issues of global change ecology as this has important implications for the carbon budget of terrestrial vegetation. Mapping vegetation distribution under historical climate scenarios is essential for understanding the response of vegetation distribution to future climatic changes. The reconstructions of palaeovegetation based on pollen data provide a useful method to understand the relationship between climate and vegetation distribution. However, this method is limited in time and space. Here, using species distribution model (SDM) approaches, we explored the climatic determinants of contemporary vegetation distribution and reconstructed the distribution of Chinese vegetation during the Last Glacial Maximum (LGM, 18,000 14C yr BP) and Middle-Holocene (MH, 6000 14C yr BP). The dynamics of vegetation distribution since the LGM reconstructed by SDMs were largely consistent with those based on pollen data, suggesting that the SDM approach is a useful tool for studying historical vegetation dynamics and its response to climate change across time and space. Comparison between the modeled contemporary potential natural vegetation distribution and the observed contemporary distribution suggests that temperate deciduous forests, subtropical evergreen broadleaf forests, temperate deciduous shrublands and temperate steppe have low range fillings and are strongly influenced by human activities. In general, the Tibetan Plateau, North and Northeast China, and the areas near the 30°N in Central and Southeast China appeared to have experienced the highest turnover in vegetation due to climate change from the LGM to the present.
Edelmann-Singer’s Koina und Concilia is a work aimed to highlight socio-economic aspects of provincial councils, which have often been downplayed or ignored in discourses concerning Roman provincial administration; but there is much more. Building upon seminal studies by Larsen ( Representative Governments in Greek and Roman History, 1955) and Deininger ( Die Provinziallandtage der römischen Kaiserzeit, 1965), Koina und Concilia attempts to shift away from the practice of studying the provincial councils separately as koina of the Greek East and conciliaof the Latin West, a separation exemplified by the important works by Fishwick ( Imperial Cult of the Latin West, 1987-2005) and Price ( Rituals and Power, 1984). The result is a general theory regarding the origin, formation processes, and functions of Roman provincial councils. Koina und Concilia is organized thematically: a literature review and the methodology of the book in the introductory chapter (chapter I, p. 13-40); historical analyses of koina and concilia in chapter II (p. 41-140); institutional analyses of the provincial councils’ legal basis and their personnel in chapter III (p. 141-192); evidence on the provincial councils’ socio-economic functions and their fostering of provincial identity in chapter IV (p. 193-309). Chapter V (p. 309-312) rehearses the main arguments. The main thrust of the book, as set out in the introduction, is Edelmann-Singer’s objection to Deininger’s view that provincial councils were of limited significance to the administrative and economic aspects of Roman provinces (p. 16-24). Her fourth chapter marshals a considerable amount of evidence to show that the members of provincial councils were involved in regional and trans-regional socio-economic activities, at times even taking on administrative tasks such as tax collection, census surveys, construction and maintenance of road networks, providing logistical support for large scale movement of troops, and monetizing the local economy. Edelmann-Singer attributes much of the disinterest in academia regarding the importance of the provincial councils to Deininger’s influential view that provincial councils were only concerned with the provincial imperial cult, the hosting of provincial games and festivities, and representing the interests of provincials against Roman provincial administration, and thus had little real impact on the life of a Roman province (p. 193). Edelmann-Singer compiles the known cases of the provincial councils’ regular and extraordinary revenues and expenditures, and examines the individual activities of their leading men, to refine Deininger’s paradigm. In the following, I provide further synopses and observations. The second chapter deals with questions of the origin and dissemination of provincial councils. Edelmann-Singer argues that the similarities in the structural design of pre-Roman and Roman koina suggest affiliation in concept (p. 35; p. 44-45), particularly with Classical and Hellenistic traditions of city-leagues that had political-institutional, religious functions, and communicative-ritual aspects (p. 54). One could perhaps understand her position as a convergence of Deininger’s Hellenistic “precursor” proposal (Deininger, Provinziallandtag, 1965, p. 7-12) and Larsen’s “hybrid” model (Larsen, Representative Government, 1955, p. 128-9), but with a historical approach or “Transferprozess” (II.6). She identifies several phases based on known foundation dates of eastern and western provincial councils to construct a dissemination narrative. The experimental phase of the Roman provincialization process with Hellenistic and Late Republican eastern koina is presented in II.2 to II.3, followed by the Augustan dissemination as described in Cassius Dio’s account of the foundation of the cult of Roma and Augustus in II.4, then to II.5, where she discusses the numerous provincial councils that appeared in a relatively short span during the early Julio-Claudian period. Most important is Edelmann-Singer’s observation that the Julio-Claudian foundations were readily found across the empire, and already consisted of varied forms of local and Roman initiatives. This observation is a strong challenge to both the so-called Lex Krascheninnikoff (that less “civilized” provinces in the Roman west were first to be installed with a provincial council and the imperial cult), as well as to Fishwick’s argument that koina and concilia established during the Julio-Claudian period were planned, while Flavian foundations were spontaneous (p. 137; also see p. 114-126 for Edelmann-Singer’s objection to Fishwick’s Flavian dating of the so-called Lex Narbonensis). The third chapter deals with the organizational aspect of provincial councils, focusing on their legal basis and officials. Edelmann-Singer asks what were the legal bases for provincial councils to possess right to assemble, to maintain independent control of revenue and expenditure, and to petition (p. 142-153). Edelmann-Singer assumes that Cassius Dio’s passage describing the foundation of the worship of divine Augustus in Pergamon and Nikomedeia implies that the provincial councils in Asia and Bithynia received a new legal status as a religious association, though this could not be proved (p. 143-144). To further substantiate this claim, she highlights literary and epigraphic evidence demonstrating that the provincial councils were treated by Roman authorities as subordinate although independent (Tac. Ann. 15.20-22; Aelius Arstides εἰς Ῥώμην 32; Cicero Verr. 2.2.137 & 145; Cod. Theod. 12.12.1 & 12.12.9). The most definitive piece of evidence seems to be the Calendar Decree of Asia, in which a letter issued by the proconsul to the Koinon of Asia included a diatagma-edictum, ordering the provincial council to reform the calendar of Asia to observe Augustus’ birthday, effectively rendering the koinon a subordinate institution (p. 150). Another important document is the so-called Lex Narbonensis (p. 148-149), which provides a glimpse of a lex collegii, with which Edelmann-Singer bundles the Dionysiac Technitai together as a reconstruction of what a provincial council might have looked like had it been indeed a private collegium (as opposed to the amplissima collegia and the sodalitates sacrae, p. 147-148). Regarding the officials of the provincial councils, Edelmann-Singer discusses in particular the provincial priesthood (III.2.1) and the koinarchy (III.2.2). She argues that the two offices represent two stages of the historical development of the provincial council in the east (p. 174). One could perhaps also read these subsections as an attempt to revise the mainstream honor-oriented discourse (such as Lendon’s approach in Empire of Honour 1997, p. 166-172) from a “provincial” perspective. While local elites indeed took part in the activities of the provincial councils in order to display wealth and prestige, the accumulative experience led to a qualitative change. Elites participated in the fostering of a “province-based” system of honor, and in turn defined a sense of provincial belonging and self-identity (p. 174-179). The fourth chapter is the longest and most complex of the book. Edelmann-Singer argues that the provincial councils were similar and comparable institutions across the empire, because the collated evidence from both the Greek East and Latin West indicates that provincial councils provided services with self-sustaining revenue structure based on trading, banking, financing, and minting operations, in addition to their relatively better known activities such emperor worship and imperial communications relating to petitions or arbitration (IV.1-IV.3). Particularly interesting is the scale of ordinary revenues that could be deduced from the epigraphical evidence found at Myra and Kaunos. If assuming an average contribution of each of the 33 cities of the Lycian koinon, one would expect no less than 165,000 denarii in annual contributions (p. 235-239). Yet, with no evidence for salaries paid to middle-status personnel, and with no comparable evidence on expenditure and revenue from provincial councils other than Lycia, the significance of the Lycian financial data becomes difficult to ascertain. Edelmann-Singer also argues that provincial councils could be tapped by imperial authorities from time to time to provide many services, such as conducting the census, collecting taxes, supplying and quartering of troops, constructing roads, and policing, among others. The proposal is intriguing, but the evidence available seems to indicate that these were extraordinary services, as Edelmann-Singer herself observed while discussing the case of Caius Valerius Arabinus, a high priest of the provincial council of Hispania exterior, who was awarded an honorific statue for having faithfully administered the office of the census (p. 260-266). Edelmann-Singer introduces transaction cost theory from New Institutional Economics to explain why koina and concilia were attractive to Roman administrators and provincial elites (IV.4.1-IV.4.3, p. 193-253; IV.4.4, p. 253-269). For Tres Galliae in particular, eleven inscriptions concerning the treasury of the provincial council that honor members of the local elite show that nearly 40% of the men who worked at the treasury were members who worked in business corporations, some even having attained senior positions, and about 55% of the treasury staff had links to the private sector or served as extraordinary financial controllers for Roman administrators (p. 253-257; esp. 254). Edelmann-Singer interprets this information as indicative of the members’ networking with each other and their awareness of lowering and stabilizing transaction costs, a speculative but nevertheless intriguing way to approach the limited evidence at hand. Finally, Edelmann-Singer discusses provincial coinage (IV.5). Cistophoric and Macedonian provincial issues are used in particular to discuss questions concerning rights of coinage, economic benefits, and the fiscal and political importance of provincial issues. Provincial coinage was issued to prepare for the large movement of troops during large military campaigns and to prepare to receive the large retinue of the emperors during imperial visits, but it was also issued to bolster the visibility of the provincial council as an active and competent body, and hence a legitimate agent, authority, and partner for a variety of purposes. One curious choice Edelmann-Singer makes is to leave out the so-called “landschaftliche Koina” (as coined by Kornmann in his 1900 RE article) – namely the leagues of cities that were region- instead of province-oriented, such as the Boiotian, Phokian, Thessalian, Arkadian and the Eleutherolakonian “leagues” in Provincia Achaia – with relatively little explanation, other than that they were not “provincial” and did not last into Late Antiquity (p. 28). This exclusion of the “landschaftliche Koina” and the reasoning behind it seem to follow Deininger’s methodology (Deininger, Provinziallandtage, 1965, p. 6). Occasionally, the distinction between these categories breaks down, as in the case of the Messenians and the Achaian koinon honoring Ti. Flavius Polybius with two statues in Olympia in the second century CE, where Edelmann-Singer even adds a footnote stating that the self-presentation of elite representatives of the regional councils shows a similar pattern to that of the members of the provincial councils (p. 177, fn. 193). Perhaps further treatment comparing regional and provincial councils would enhance our understanding of regional vs. provincial associations. To conclude, Edelmann-Singer’s book has the potential to change the discourse on provincial councils and Roman provincial administration altogether. Her extensive review of the origins, formation processes, legal bases, personnel, expenditures, revenues and activities of provincial councils in the Greek East and the Latin West, as well as her introduction of New Institutional Economics and the numismatic approach to flesh out the significance of provincial councils, demonstrate how the study of provincial councils ought to be extended from existing discourse on honor and emperor worship to socio-economic and even cultural factors. Perhaps more tabulations are needed to bring clarity to each chapter, since foundation dates and the changing status, rights and activities of provincial councils through time can be hard to follow. Nevertheless, Edelmann-Singer’s work provides an extensive dossier of evidence pertaining provincial councils as well as a intriguing set of theoretical proposals which will enable students of Roman provincial administration to reconsider existing analytical paradigms.
China is facing serious haze problems due to the levels of fine particulate matter (PM2.5). Therefore, source apportionment of PM2.5 is required for formulating effective air pollution control strategies. The fast increase of the vehicle population, especially in the megacities of China in recent years, makes vehicular emissions one of the most important sources of PM2.5 and has led to it receiving great attention and concern. There is an urgent need to accurately and quantitatively estimate the contribution of vehicular emissions. A growing number of studies have been conducted for source apportionment of PM2.5 in China and report the contribution from vehicular emissions using different methods. However, it is still a big challenge as to how vehicular emissions can be accurately quantified.
This study summarizes the various methods that have been used to identify and quantify the vehicular emissions contribution to PM2.5 in published literature by international and domestic scientists, lists advantages and disadvantages of each method, and proposes ways to reduce its uncertainty. In general, methods for estimating vehicular emission contributions in previous studies include emission inventory based methods, chemical transport models, receptor models, hybrid models etc. The receptor model based method is the most commonly applied method in China. Source profiles of vehicular emissions based on source testing in China, and organic and inorganic tracers used for diagnosing vehicular emissions, which are two key factors for quantifying vehicular exhaust in receptor models, are also summarized here.
Contributions of vehicular emissions to ambient PM2.5 reported in different areas in China, especially Beijing, are listed and compared. It can be seen that the contribution of vehicular emissions to PM2.5 varies significantly with the study area, year of the study, as well as the methods in use. The vehicular emissions contribution to PM2.5 in Beijing is reported to be in the range of 4%–36% based on previous studies from 1989 to 2014, primarily using the receptor model method.
This work also points out challenges in the current studies, provides suggestions in order to better quantify the contribution from vehicular emissions in China, and proposes ways to optimize the methods. For example, besides primary emissions from vehicular exhaust, quantifying secondary organic and inorganic aerosols formed from gaseous and particulate precursors from vehicular emissions, as well as traffic related sources (e. g., resuspended road dust) is also a big concern and challenge for accurately estimating vehicular emissions. In addition, there is still a pressing need to develop more detailed and comprehensive chemical profiles and an emissions inventory of vehicular emissions, with standardized sampling and analytical protocols in the future. An improved emission inventory with high time, spatial and species resolutions should be established. A hybrid model, which integrates emission inventory, chemical transport model, receptor model and observational data is a promising direction to provide an accurate estimate of vehicular emissions in the future. In addition, there is a need to develop a system to verify the results obtained from a source apportionment study.
The discovery of sodium taurocholate cotransporting polypeptide (NTCP) as the hepatitis B virus (HBV) receptor enabled researchers to create hepatoma cell lines susceptible to HBV infection. Infection in current systems, however, is inefficient and virus fails to spread. Infection efficiency is enhanced by treating cells with polyethylene glycol 8000 (PEG) during infection. However, this alone does not promote virus spread. Here we show that maintaining PEG in culture medium increases the rate of infection by at least one order of magnitude, and, most importantly, promotes virus spread. To demonstrate the utility of this system, we show that two interferon-stimulated genes (ISGs), ISG20 and tetherin, restrict HBV spread in NTCP-expressing hepatoma cells. Thus, this protocol can be easily applied to existing cell culture systems to study the complete HBV life cycle, including virus spread.
Practical and optimal reduction of watershed loads under deep uncertainty requires sufficient search alternatives and direct evaluation of robustness. These requirements contribute to the understanding of the tradeoff between cost and robustness; while they are not well addressed in previous studies. This study thereby (a) uses preconditioning technique in Evolutionary Algorithm to reduce unnecessary search space, which enables a sufficient search; and (b) derives Robustness Index (RI) as a second-tier optimization objective function to achieve refined solutions (solved by GA) that address both robustness and optimality. Uncertainty-based Refined Risk Explicit Linear Interval Programming is used to generate alternatives (solved by Controlled elitist NSGA-II). The robustness calculation error is also quantified. Proposed approach is applied to Lake Dianchi, China. Results demonstrate obvious improvement in robustness after conducting sufficient search and negative robustness-optimality trade-offs, and provides a detailed characteristic of robustness that can serve as references for decision-making.
The challenge of continuous printing in high-efficiency large-area organic solar cells is a key limiting factor for their widespread adoption. A materials design concept for achieving large-area, solution-coated all-polymer bulk heterojunction solar cells with stable phase separation morphology between the donor and acceptor is presented. The key concept lies in inhibiting strong crystallization of donor and acceptor polymers, thus forming intermixed, low crystallinity, and mostly amorphous blends. Based on experiments using donors and acceptors with different degree of crystallinity, the results show that microphase separated donor and acceptor domain sizes are inversely proportional to the crystallinity of the conjugated polymers. This methodology of using low crystallinity donors and acceptors has the added benefit of forming a consistent and robust morphology that is insensitive to different processing conditions, allowing one to easily scale up the printing process from a small-scale solution shearing coater to a large-scale continuous roll-to-roll (R2R) printer. Large-area all-polymer solar cells are continuously roll-to-roll slot die printed with power conversion efficiencies of 5%, with combined cell area up to 10 cm2. This is among the highest efficiencies realized with R2R-coated active layer organic materials on flexible substrate.
For devices with a 15 micron anode-to-cathode distance, nearly 1.5 times increase in the blocking (breakdown) voltage (from 692 to 1030 V) has been achieved by replacing the alloyed Ohmic contact at the anode electrode of the conventional MOS gated hybrid-anode lateral field-effect rectifier (CMLFER) with a low barrier Schottky contact. The new Schottky-MOS hybrid-anode lateral field-effect rectifier is found to offer comparable low onset voltage (V-ON of 0.68 +/- 0.13 versus 0.65 +/- 0.11 V for CMLFER) independent of the anode-to- cathode distance. The immunity of the punch through caused by drain induced barrier lowering effect is obtained through the low barrier Schottky contact in anode, which is believed to be responsible for the reduction in the leakage current, and the improvement of rectifier breakdown voltage.
53#,a strain of efficient alginate degrading bacteria,is isolated from rotted kelp using sodium alginate as the only carbon resource. Strain 53# is identified as Paenibacillus agaridevorans based on physiological characteristics and 16S rRNA sequencing. The optimaltion yield condition of strain 53# is identified at ${\rm{pH = 8}}$,$T = 25^\circ {\rm{C}}$,NaCl 15 g/L,and sodium alginate 15 g/L by orthogonal experiment and analysis,and the highest enzyme activity is ${\rm{390}}{\rm{.53}} \pm {\rm{17}}{\rm{.32\;U/mL}}$. Strain 53# has the advantages such as being cultivated easily,producing enzyme fast and having high enzyme activity. It can achieve a high efficiency for saccharification of alginate and thus has potential value to be utilized in the production of bioethanol from brown algae.以海藻酸钠为唯一碳源,从天然腐烂海带中筛选得到一株高效褐藻胶降解菌株53#,经形态学观察和16S rRNA鉴定,确定为类芽孢杆菌Paenibacillus agaridevorans。采用正交试验方法,以pH、温度、NaCl浓度和海藻酸钠初始浓度为影响因素,对该菌株的产酶条件进行优化,得到53#菌的 最佳产酶条件: ${\rm{pH = 8}}$,25℃,NaCl浓度15 g/L,海藻酸钠初始浓度15 g/L。在最佳产酶条件下,褐藻胶裂解酶最大酶活可达${\rm{390}}{\rm{.53}} \pm {\rm{17}}{\rm{.32\;U/mL}}$。筛选得到的类芽孢杆菌Paenibacillus agaridevorans 53#具有易于培养、产酶速度快和酶活力高等优点,能够实现褐藻胶的高效糖化,在褐藻生产生物乙醇领域具有潜在利用价值。
The self-assemblies of polycyclic aromatic diimide (PAI) compounds on solid surfaces have attracted great interest because of the versatile and attractive properties for application in organic electronics. Here, a planar guest species (coronene) selectively adsorbs on the helicene-typed PAI1 monolayer strongly, depending on the conjugated cores of these PAIs. PAI1 molecule displays evidently a bowl structure lying on the highly oriented pyrolytic graphite surface due to the torsion of the "C"-shaped fused benzene rings. In combination with density functional theory calculation, the selective inclusion of coronene atop the backbone of the PAI1 array might be attributed to the bowl structure, which provides a groove for immobilizing coronene molecules. On the other planar densely packed arrays, it is difficult to observe the unstable adsorption of coronene. The selective addition of coronene molecules would be a strategic step toward the controllable multicomponent supramolecular architectures.
