bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate geometries for “Mountain pass” regions of the Ramachandran plot using quantum chemical calculations
Authors: Jiang Zhongming , Biczysko Malgorzata , Moriarty Nigel W.
Published: January 2018

Unusual local arrangements of protein in Ramachandran space are not well represented by standard geometry tools used in either protein structure refinement using simple harmonic geometry restraints or in protein simulations using molecular mechanics force fields. In contrast, quantum chemical computations using small poly‐peptide molecular models can predict accurate geometries for any well‐defined backbone Ramachandran orientation. For conformations along transition regions—ϕ from −60 to 60°—a very good agreement with representative high‐resolution experimental X‐ray (≤1.5 Å) protein structures is obtained for both backbone C−1‐N‐Cα angle and the nonbonded O−1…C distance, while “standard geometry” leads to the “clashing” of O…C atoms and Amber FF99SB predicts distances too large by about 0.15 Å. These results confirm that quantum chemistry computations add valuable support for detailed analysis of local structural arrangements in proteins, providing improved or missing data for less understood high‐energy or unusual regions.
Small angle X‐ray scattering and cross‐linking for data assisted protein structure prediction in CASP 12 with prospects for improved accuracy
Authors: Ogorzalek Tadeusz L. , Hura Greg L. , Belsom Adam , Burnett Kathryn H. , Kryshtafovych Andriy , Tainer John A. , Rappsilber Juri , Tsutakawa Susan E. , Fidelis Krzysztof
Published: January 2018

Experimental data offers empowering constraints for structure prediction. These constraints can be used to filter equivalently scored models or more powerfully within optimization functions toward prediction. In CASP12, Small Angle X‐ray Scattering (SAXS) and Cross‐Linking Mass Spectrometry (CLMS) data, measured on an exemplary set of novel fold targets, were provided to the CASP community of protein structure predictors. As solution‐based techniques, SAXS and CLMS can efficiently measure states of the full‐length sequence in its native solution conformation and assembly. However, this experimental data did not substantially improve prediction accuracy judged by fits to crystallographic models. One issue, beyond intrinsic limitations of the algorithms, was a disconnect between crystal structures and solution‐based measurements. Our analyses show that many targets had substantial percentages of disordered regions (up to 40%) or were multimeric or both. Thus, solution measurements of flexibility and assembly support variations that may confound prediction algorithms trained on crystallographic data and expecting globular fully‐folded monomeric proteins. Here, we consider the CLMS and SAXS data collected, the information in these solution measurements, and the challenges in incorporating them into computational prediction. As improvement opportunities were only partly realized in CASP12, we provide guidance on how data from the full‐length biological unit and the solution state can better aid prediction of the folded monomer or subunit. We furthermore describe strategic integrations of solution measurements with computational prediction programs with the aim of substantially improving foundational knowledge and the accuracy of computational algorithms for biologically‐relevant structure predictions for proteins in solution.
On distinguishing snowfall from rainfall using near‐surface atmospheric information: Comparative analysis, uncertainties and hydrologic importance
Authors: Behrangi Ali , Yin Xungang , Rajagopal Seshadri , Stampoulis Dimitrios , Ye Hengchun
Published: January 2018

The accurate estimation of precipitation phase has broad applications. In this study, we compared the skill of using various atmospheric variables and their combinations as predictors in accurately identifying surface precipitation phase, determined uncertainties associated with commonly used fixed temperature thresholds, and explored the sensitivity of hydrologic model output to uncertainty in precipitation phase using two case‐studies. The results suggest that among all single predictors, wet‐bulb temperature yields the highest skill score for determining precipitation phase and can reduce uncertainties due to regional differences, especially compared to the commonly used near‐surface air temperature. However, addition of good‐quality near‐surface wind speed measurement to dew‐point temperature and pressure showed slightly higher skill than wet‐bulb temperature. We showed that the scale mismatch between temperature from stations and gridded products can cause large uncertainties in determining precipitation phase, especially in regions with rugged topography. Such uncertainties need to be considered when the relationships developed based on station data are applied to remote‐sensing observations and model‐generated data to separate rain from snowfall. The sensitivity of hydrologic model outputs to uncertainty in precipitation phase delineation was also assessed over two major basins in California by modifying default near‐surface temperatures used in the Variable Infiltration Capacity (VIC) model. It was found that regional and scaling uncertainties in determining temperature thresholds can largely influence the accuracy of simulated downstream runoff and snow water equivalent (SWE) (e.g. up to 40% change in SWE for 2 °C shift in temperature threshold). Therefore, to reduce simulation uncertainties, it is important to improve rain–snow partitioning methods, consider regional variabilities in determining temperature thresholds, and perform the analysis at the highest possible resolutions to mitigate scale‐related uncertainties.
Delay and state observation for SISO nonlinear systems with input delay
Authors: Léchappé Vincent , De Léon Jesús , Moulay Emmanuel , Plestan Franck , Glumineau Alain
Published: January 2018

This paper deals with the problem of state and delay estimation for SISO nonlinear systems with an unknown time‐varying delay in the input. The main idea is to approximate the delayed input by using Taylor's theorem and to create an extended system with the delay as part of the extended state. Then, the construction of an observer is proposed to estimate both state and delay. The results are illustrated by simulations.
Determination of the metabolites of Δ9‐tetrahydrocannabinol in urine and plasma using multiple reaction monitoring gas chromatography with triple quadrupole mass spectrometry
Authors: Leghissa Allegra , Hildenbrand Zacariah L. , Foss Frank W. , Schug Kevin A.
Published: January 2018

Once introduced into the human body, only minimal amounts of cannabinoids are excreted in their original forms, due to various complex metabolic pathways. For this reason, it is less desirable to quantify the amount of parent cannabinoids in urine, plasma, or feces, as opposed to the pertinent cannabinoid metabolites. Δ9‐Tetrahydrocannabinol is reported to be the most potent and psychoactive among natural cannabinoids. Here, two known metabolites, 11‐hydroxy‐Δ9‐tetrahydrocannabinol and 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol, plus their precursor Δ9‐tetrahydrocannabinol, were targeted for analysis. We describe the creation of a method using gas chromatography with triple quadrupole mass spectrometry and multiple reaction monitoring mode for these two metabolites. The analytes were silylated prior to analysis. The validation of the methods using samples of urine and plasma spiked with known amounts of the metabolites was shown to provide recoveries between 80 and 110%, limits of detection were 75 pg for both Δ9‐tetrahydrocannabinol and 11‐hydroxy‐Δ9‐tetrahydrocannabinol, and 25 ng for 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol in their silylated forms.
Activation of AKT-mTOR Signaling Directs Tenogenesis of Mesenchymal Stem Cells
Authors: Cong Xiao Xia , Rao Xi Sheng , Lin Jun Xin , Liu Xiao Ceng , Zhang Guang An , Gao Xiu Kui , He Min Yi , Shen Wei Liang , Fan Wei , Pioletti Dominique , Zheng Li Ling , Liu Huan Huan , Yin Zi , Low Boon Chuan , Schweitzer Ronen , Ouyang Hongwei , Chen Xiao , Zhou Yi Ting
Published: January 2018

Tendon repair is a clinical challenge because of the limited understanding on tenogenesis. The synthesis of type I collagen (Collagen I) and other extracellular matrix are essential for tendon differentiation and homeostasis. Current studies on tenogenesis focused mostly on the tenogenic transcriptional factors while the signaling controlling tenogenesis on translational level remains largely unknown. Here, we showed that mechanistic target of rapamycin (mTOR) signaling was activated by protenogenic growth factor, transforming growth factors beta1, and insulin-like growth factor-I. The expression of mTOR was upregulated during tenogenesis of mesenchymal stem cells (MSCs). Moreover, mTOR was downregulated in human tendinopathy tissues and was inactivated upon statin treatment. Both inhibition and depletion of AKT or mTOR significantly reduced type I collagen production and impaired tenogenesis of MSCs. Tendon specific-ablation of mTOR resulted in tendon defect and reduction of Collagen I. However, there is no evident downregulation of tendon associated collagens at the transcription level. Our study demonstrated that AKT-mTOR axis is a key mediator of tendon differentiation and provided a novel therapeutic target for tendinopathy and tendon injuries.
Building Up Functional Bionanocomposites from the Assembly of Clays and Biopolymers
Authors: Alcântara Ana C. S. , Darder Margarita
Published: January 2018

Functional bionanocomposites are developed from the assembly of naturally occurring polymers and inorganic solids that show at least one dimension at the nanoscale. Our research group focused on the development of bionanocomposites based on clay minerals, including smectites and fibrous silicates, as well as layered double hydroxides. The resulting materials show interesting properties regarding biocompatibility and biodegradability, together with improved mechanical and thermal properties in comparison to the pristine biopolymer. Besides these characteristics, they offer also other interesting functional properties that allow their potential use in a wide range of applications, including sensors, drug delivery and other health care applications, bioplastics and environmental remediation. For these materials, nature provides not only the components but also the inspiration to develop new combinations that may give rise to nanostructured biomaterials with exceptional features.
Nanoparticles Formed onto/into Halloysite Clay Tubules: Architectural Synthesis and Applications
Authors: Vinokurov Vladimir A. , Stavitskaya Anna V. , Glotov Aleksandr P. , Novikov Andrei A. , Zolotukhina Anna V. , Kotelev Mikhail S. , Gushchin Pawel A. , Ivanov Evgenii V. , Darrat Yusuf , Lvov Yuri M.
Published: January 2018

Nanoparticles, being objects with high surface area are prone to agglomeration. Immobilization onto solid supports is a promising method to increase their stability and it allows for scalable industrial applications, such as metal nanoparticles adsorbed to mesoporous ceramic carriers. Tubular nanoclay – halloysite – can be an efficient solid support, enabling the fast and practical architectural (inside / outside) synthesis of stable metal nanoparticles. The obtained halloysite‐nanoparticle composites can be employed as advanced catalysts, ion‐conducting membrane modifiers, inorganic pigments, and optical markers for biomedical studies. Here, we discuss the possibilities to synthesize halloysite decorated with metal, metal chalcogenide, and carbon nanoparticles, and to use these materials in various fields, especially in catalysis and petroleum refinery.
Effects of Neuromodulation on Excitatory–Inhibitory Neural Network Dynamics Depend on Network Connectivity Structure
Authors: Rich Scott , Zochowski Michal , Booth Victoria
Published: January 2018

Acetylcholine (ACh), one of the brain’s most potent neuromodulators, can affect intrinsic neuron properties through blockade of an M-type potassium current. The effect of ACh on excitatory and inhibitory cells with this potassium channel modulates their membrane excitability, which in turn affects their tendency to synchronize in networks. Here, we study the resulting changes in dynamics in networks with inter-connected excitatory and inhibitory populations (E–I networks), which are ubiquitous in the brain. Utilizing biophysical models of E–I networks, we analyze how the network connectivity structure in terms of synaptic connectivity alters the influence of ACh on the generation of synchronous excitatory bursting. We investigate networks containing all combinations of excitatory and inhibitory cells with high (Type I properties) or low (Type II properties) modulatory tone. To vary network connectivity structure, we focus on the effects of the strengths of inter-connections between excitatory and inhibitory cells (E–I synapses and I–E synapses), and the strengths of intra-connections among excitatory cells (E–E synapses) and among inhibitory cells (I-I synapses). We show that the presence of ACh may or may not affect the generation of network synchrony depending on the network connectivity. Specifically, strong network inter-connectivity induces synchronous excitatory bursting regardless of the cellular propensity for synchronization, which aligns with predictions of the PING model. However, when a network’s intra-connectivity dominates its inter-connectivity, the propensity for synchrony of either inhibitory or excitatory cells can determine the generation of network-wide bursting.
Regularity for nonlinear stochastic games
Authors: Luiro Hannes , Parviainen Mikko
Published: January 2018

We establish regularity for functions satisfying a dynamic programming equation, which may arise for example from stochastic games or discretization schemes. Our results can also be utilized in obtaining regularity and existence results for the corresponding partial differential equations.
Regional vulnerability in Alzheimer's disease: The role of cell‐autonomous and transneuronal processes
Authors: Acosta Diana , Powell Fontasha , Zhao Yize , Raj Ashish
Published: January 2018

Introduction

The stereotypical progression of Alzheimer's disease (AD) pathology is not fully understood. The selective impact of AD on distinct regions has led the field to question if innate vulnerability exists. This study aims to determine if the causative factors of regional vulnerability are dependent on cell‐autonomous or transneuronal (non–cell autonomous) processes.

Methods

Using mathematical and statistical models, we analyzed the contribution of cell‐autonomous and non–cell autonomous factors to predictive linear models of AD pathology.

Results

Results indicate gene expression as a weak contributor to predictive linear models of AD. Instead, the network diffusion model acts as a strong predictor of observed AD atrophy and hypometabolism.

Discussion

We propose a convenient methodology for identifying genes and their role in determining AD topography, in comparison with network spread. Results reinforce the role of transneuronal network spread on disease progression and suggest that innate gene expression plays a secondary role in seeding and subsequent disease progression.
Avaliação funcional da reconstrução do ligamento patelofemoral medial em atletas
Authors: Garms Emerson , Carvalho Rogerio Teixeira de , Janovsky César , Nicolini Alexandre Pedro , Salviani Rafael Salmeron , Liggieri Andre Cicone
Published: January 2018

Objetivo Avaliar os resultados clínicos e funcionais da reconstrução anatômica do ligamento patelofemoral medial com tendões flexores em atletas.

Métodos Estudo tipo série de casos, prospectivo, que analisou a reconstrução do ligamento patelofemoral medial em 32 pacientes (34 joelhos). A avaliação funcional foi feita pelos escores Lysholm e Kujala nos períodos pré e pós-operatórios e os fatores de risco envolvidos foram avaliados.

Resultados Dos 32 pacientes analisados, todos obtiveram melhoria dos escores funcionais comparativamente ao período pré-operatório. Pacientes com menos de cinco episódios de luxação prévios obtiveram melhores resultados funcionais. O valor médio de Lysholm no pré-operatório foi de 62,8 e no pós-operatório de 94,3, quanto ao escore de Kujala a média pré-operatório foi de 63,0 e pós-operatória de 94,0.

Conclusão A reconstrução do ligamento patelofemoral medial com enxerto de tendão flexor do joelho em atletas propiciou melhoria dos escores clínicos e funcionais nos pacientes com instabilidade patelofemoral. A perfuração óssea da patela e o posicionamento do túnel femoral devem ocorrer de forma judiciosa.
The challenge of monitoring glaciers with extreme altitudinal range: mass-balance reconstruction for Kahiltna Glacier, Alaska
Authors: YOUNG JOANNA C. , ARENDT ANTHONY , HOCK REGINE , PETTIT ERIN
Published: January 2018

Glaciers spanning large altitudinal ranges often experience different climatic regimes with elevation, creating challenges in acquiring mass-balance and climate observations that represent the entire glacier. We use mixed methods to reconstruct the 1991–2014 mass balance of the Kahiltna Glacier in Alaska, a large (503 km2) glacier with one of the greatest elevation ranges globally (264–6108 m a.s.l.). We calibrate an enhanced temperature index model to glacier-wide mass balances from repeat laser altimetry and point observations, finding a mean net mass-balance rate of −0.74 mw.e. a−1( ± σ = 0.04, std dev. of the best-performing model simulations). Results are validated against mass changes from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites, a novel approach at the individual glacier scale. Correlation is strong between the detrended model- and GRACE-derived mass change time series (R2 = 0.58 and p ≪ 0.001), and between summer (R2 = 0.69 and p = 0.003) and annual (R2 = 0.63 and p = 0.006) balances, lending greater confidence to our modeling results. We find poor correlation, however, between modeled glacier-wide balances and recent single-stake monitoring. Finally, we make recommendations for monitoring glaciers with extreme altitudinal ranges, including characterizing precipitation via snow radar profiling.
Levantine Joint-Stock Companies, Trans-Mediterranean Partnerships, and Nineteenth-Century Capitalist Development
Authors: Alff Kristen
Published: January 2018

The Levantine business community—the Sursuqs, Bustruses, Tuenis, Khuris, Debbases, Trads, Tabets, Naggiars, and Farahs—created large agricultural estates in the Levant and established company branches in Beirut, Alexandria, Haifa, London, Liverpool, Paris, and Marseille in the mid-nineteenth century. Against both culturalist and new institutional paradigms, I argue that the trajectories of the Levantine firms were much like those of their European counterparts; Dutch and English capitalism—what came to be recognized as modern forms of capitalism—developed out of long-distance trade and relied on forms of coerced and semi-coerced labor as well as other so-called “non-capitalist” or “precapitalist” elements. Beirut-based companies relied on tenant contracts, sharecropping, and other forms of labor control rooted in the Ottoman social formation. Drawing upon the unexplored private papers of these business families in Beirut and a diverse collection of documents from Istanbul, Beirut, Jerusalem, London, Liverpool, and Marseille in Arabic, German, Ottoman Turkish, and French, this paper examines the parallels and the links between the business practices of the Levantine joint-stock companies and their European partners. It contends that the development of nineteenth-century capitalism relied on several different institutions and relations of production formulated and articulated on both sides of the Mediterranean and in the competition between them. Only after World War I, because of settler-colonialism, the settlement of nomads, and large-scale European capital investment backed by imperial power, did Levantine capital accumulation begin to take a form that was subordinate to Europe.
Politics and the Work of the Dead in Modern India
Authors: Moffat Chris
Published: January 2018

This article provides a framework for understanding the continuing political potential of the anticolonial dead in twenty-first-century India. It demonstrates how scholars might move beyond histories of reception to interrogate the force of inheritance in contemporary political life. Rather than the willful conjuring of the dead by the living, for a politics in the present, it considers the more provocative possibility that the dead might themselves conjure politics—calling the living to account, inciting them to action. To explicate the prospects for such an approach, the article traces the contested afterlives of martyred Indian revolutionary Bhagat Singh (1907–1931), comparing three divergent political projects in which this iconic anticolonial hero is greeted as interlocutor in a struggle caught “halfway.” It is this temporal experience of “unfinished business”—of a revolution left incomplete, a freedom not yet perfected—that conditions Bhagat Singh's appearance as a contemporary in the political disputes of the present, whether they are on the Hindu nationalist right, the Maoist student left, or amidst the smoldering remains of Khalistani separatism in twenty-first-century Punjab. Exploring these three variant instances in which living communities affirm Bhagat Singh's stake in the struggles of the present, the article provides insight into the long-term legacies of revolutionary violence in India and the relationship between politics and the public life of history in the postcolonial world more generally.
Orthodox Internationalism: State and Church in Modern Russia and Ethiopia
Authors: Rupprecht Tobias
Published: January 2018

Russia and Ethiopia, both multiethnic empires with traditionally orthodox Christian ruling elites, from the nineteenth century developed a special relationship that outlived changing geopolitical and ideological constellations. Russians were fascinated with what they saw as exotic brothers in the faith, and Ethiopians took advantage of Russian help and were inspired by various features of modern Russian statecraft. This article examines contacts and interactions between the elites of these two distant countries, and the changing relations between authoritarian states and Orthodox churches from the age of European imperialism to the end of the Cold War. It argues that religio-ethnic identities and institutionalized religion have grounded tenacious visions of global political order. Orthodoxy was the spiritual basis of an early anti-Western type of globalization, and was subsequently coopted by states with radically secular ideologies as an effective means of mass mobilization and control.
Control of Leafy Spurge (Euphorbia esula) in Nebraska with the Spurge Hawkmoth (Hyles euphorbiae)
Authors: Forwood J. R. , McCarty M. K.
Published: January 2018

The feasibility of using the spurge hawkmoth (Hyles euphorbiaeL., Lepidoptera: Sphingidae), as a biological control agent on leafy spurge (Euphorbia esulaL.) was evaluated. Studies relating adult hawkmoth emergence from the pupal stage and spring growth of leafy spurge plants showed that the plants would provide food and oviposition sites for the insect. Two generations of the insect may occur each year. Winter temperatures at approximately 2.5 cm below the soil surface or in the litter would result in some mortality of hawkmoth pupae. Pupal release programs indicated that protection from insect and rodent predators was necessary for adult emergence to occur. Predator determination using32P indicated two specimens ofCalosoma calidumFab. and two specimens ofFormica subsericeaSay as possible predators. Predator determination using pitfall traps showed that several species listed by Canadian researchers as predators were present in leafy spurge stands in Nebraska. At this time it appears the spurge hawkmoth will not become a valuable biological control agent for leafy spurge in Nebraska.
Inhibition of Mesquite (Prosopis julifloravar.glandulosa) Growth by Fosamine
Authors: Morey P. R. , Dahl B. E.
Published: January 2018

Fosamine [ethyl hydrogen (aminocarbonyl)phosphonate] acted as a chemical inhibitor of shoot growth for periods of up to 3 yr following a single summer application to honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell] trees. Anatomical study of field, greenhouse, and seedling mesquite indicated that the inhibition of primary and secondary growth caused by fosamine was due to a general cessation of nuclear activity in apical meristems and in the vascular and cork cambia of this species.
Potential Antidotes Against Buthidazole Injury to Corn (Zea mays)
Authors: Hatzios Kriton K. , Penner Donald
Published: January 2018

Buthidazole {3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone} may be useful for selective weed control in corn (Zea maysL.) but injures corn seedlings at high rates. Greenhouse studies were initiated to test potential antidotes for buthidazole injury to corn seedlings. NA (1,8-naphthalic anhydride) and CDAA (N,N-diallyl-2-chloroacetamide) were the most effective of six chemicals evaluated. A ratio of 1:3 (buthidazole: CDAA) appeared to be optimal for the protection effect. CDAA appeared to be more effective than NA. Since both CDAA and NA offered limited protection but R-25788 did not, this action appears to be through a different mechanism than the one proposed for the thiocarbamate or acetanilide herbicides. The other chemicals tested were R-25788 (2,2-dichloro-N,N-diallylacetamide), R-29148 (2,2-dimethyl-5-methyl-dichloroace-tyloxazolidine), carboxin (2,3-dihydro-5-carboxanilido-6-methyl-1,4-oxanthiin) and gibberellin (GA3). Seven herbicides, members of the acetanilide, thiocarbamate, and dinitroaniline groups, were also tested for their antagonistic interactions but none offered protection.
Control of Volunteer Wheat (Triticum aestivum) in Fall-Planted Perennial Ryegrass (Lolium perennne) with Ethofumesate
Authors: Lee W. O.
Published: January 2018

Ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] was evaluated in field experiments at rates from 0.6 to 4.5 kg/ha for control of volunteer wheat (Triticum aestivumL. ‘Hyslop’, ‘Stephens’) in fall-planted perennial ryegrass (Lolium perenneL. ‘Cropper’, ‘Pelo’, ‘Pennfine’, ‘Omega’). Ethofumesate applied at 1.7 kg/ha or more in mid-November to wheat in the one-to three-leaf stage eliminated the wheat. Wheat was not eliminated when ethofumesate was applied preemergence soon after planting or when applied at the end of November to wheat in the four-leaf to four-tiller stage. In four experiments in which wheat was present, ethofumesate significantly increased perennial ryegrass seed production. In one experiment in which wheat was not present, ethofumesate did not affect perennial ryegrass seed production. Ethofumesate applied in the fall at rates to 4.5 kg/ha to newly-seeded perennial ryegrass or to well-established bentgrass (Agrostis tenuisSibth. ‘Highland’), Kentucky bluegrass (Poa pratensisL. ‘Newport’), and Italian ryegrass (Lolium multiflorumLam.) did not adversely affect germination of the following seed crop.
Effects of Benefin Vaporizing from Soils on Tobacco (Nicotiana tabacum) Foliage
Authors: Yamasue Y. , Worsham A. D.
Published: January 2018

In closed vapor exposure chambers, foliar injury on tobacco (Nicotiana tabacumL. ‘Speight G-28’) seedlings was caused by vapors arising from soils in which technical grade benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) or its commercially-formulated emulsifiable concentrate had been incorporated. The emulsifier alone did not cause injury. Dosages of the herbicide ranged from 0.84 to 6.72 kg/ha or 13.1 to 104.8 ppmw in the concentration in soils, and the lowest dosage was sufficient to induce the foliar injury. Leaves which developed during the exposure were markedly shortened, narrowed, and thickened, distorted in shape, and had an extremely poor lamina expansion and abnormal venation pattern. Severity of the foliar injury increased as the herbicide dosage and soil moisture increased, and as the soil organic matter content decreased. Leaves which were partially expanded before the exposure were affected much less. When exposed to vapors of14C-benefin, plant seedlings readily absorbed radioactive materials by its entire foliage including the stem tip with a few tiny developing leaves. More than half of the14C absorbed and adsorbed during a 3-day exposure was recovered by CHCl3wash of leaves and appeared to be retained by the wax and cutin layers, and also by lipoidal secretion substances of the numerous trichomes on the leaf surface. There was a small fraction of unabsorbed or loosely retained14C material on the surface of the leaves and stem tip, which was removed by water. That not recovered from H2O and CHCl3washes appeared to be distributed in the internal tissues. Little acropetal translocation appeared to occur from the expanded leaves toward the stem tip. There was no translocation of14C-benefin into roots of plants where only a single leaf was exposed to the radioactive vapors.
Control of Egyptian Broomrape (Orobanche aegyptiaca) and Other Weeds by Means of Solar Heating of the Soil by Polyethylene Mulching
Authors: Jacobsohn R. , Greenberger A. , Katan J. , Levi M. , Alon H.
Published: January 2018

Mulching the soil with polyethylene sheets before sowing during the hot season, increased the soil temperatures, which resulted in the control of soil-borne pathogens and weeds. This method was tested in a field heavily infested with Egyptian broomrape (Orobanche aegyptiaca L.). Soil was irrigated and mulched for 36 days during August–September 1977, prior to sowing carrot (Daucus carota L. ‘Nantes Tip Top’) seeds. Mulching increased soil temperatures by 8 to 12 C, up to 56 C in the top 5 cm. In the non-mulched plots the carrot plants became stunted due to heavy parasitization with broomrape and they were completely destroyed by the end of the season. In contrast, broomrape and other weeds were controlled in the mulched plots and the carrot plants grew normally. This effect was less pronounced in the border rows of the mulched plots. Mulching also greatly reduced the infestation of other weeds. Egyptian broomrape was also controlled in two other field experiments with carrots and eggplants (Solanum melongena L. ‘Black oval’). As compared with fumigation, this new method of control is economical, simple, nonhazardous, and does not employ toxic materials.
Smutgrass (Sporobolus poiretii) Control in South Florida
Authors: Mislevy P. , Currey W. L.
Published: January 2018

Various chemical and cultural treatments were evaluated for smutgrass [Sporobolus poiretii (R.&S.) Hitchc], control and their effects on pangolagrass (Digitaria decumbens Stent.) and bahiagrass (Paspalum notatum Flügge). Herbicide treatments were dalapon (2,2-dichloropropionic acid) at 1.7, 3.3, and 5.0 kg/ha with Sunoco HE spraying oil at 0, 9.4, 19.0 and 37.0 L/ha. Five weeks after herbicide treatment plots were clipped (clipped vs. nonclipped) and fertilized (0 vs. 112 kg/ha N). Increasing dalapon from 1.7 to 5.0 kg/ha increased smutgrass control and decreased the number of smutgrass plants/plot. Pangolagrass ground cover generally increased with fertilization, as the rate of dalapon increased up to 3.9 kg/ha. Bahiagrass ground cover decreased with rates of dalapon above 1.7 kg/ha. Increasing the rate of oil increased bahiagrass ground cover after 90 days. Nitrogen applied 5 weeks after dalapon treatment and semi-annually for 5 yr generally decreased ground cover of smutgrass and bahiagrass, but increased pangolagrass. Clipping treated smutgrass plants increased pangolagrass and bahiagrass ground cover while decreasing the ground cover of smutgrass.
Influence of Afterripening Temperature and Endogenous Rhythms on Downy Brome (Bromus tectorum) Germination
Authors: Thill D. C. , Schirman R. D. , Appleby A. P.
Published: January 2018

Afterripening requirements and the possible occurrence of endogenously controlled germination rhythms in downy brome (Bromus tectorumL.) were investigated in the laboratory. Afterripening temperatures from 0 to 50 C, maintained for periods of 4 to 28 days, had little effect on the percentage and rate of downy brome germination when seeds were incubated at 15 and 20 C. However, at 30 C germination temperature, the percentage and rate of germination were significantly increased by short periods (4 to 7 days) of afterripening at 50 C. Similar results occurred at 20 to 40 C afterripening temperatures after 14 to 28 days exposure. In general, high temperature afterripening conditions (40 to 50 C) initially increased downy brome germination at 30 C incubation temperature, but prolonged exposure tended to decrease germination. No endogenously controlled germination rhythms were observed in downy brome caryopses.
Yellow Nutsedge (Cyperus esculentus) Competition with Cotton (Gossypium hirsutum)
Authors: Patterson M. G. , Buchanan G. A. , Street J. E. , Crowley R. H.
Published: January 2018

Two series of experiments were conducted from 1976 through 1978 on Marvyn loamy sand in central Alabama to determine the competitive relationship of yellow nutsedge (Cyperus esculentusL.) with cotton (Gossypium hirustumL. ‘Stoneville 213’). In the first series of experiments yellow nutsedge was left undisturbed or removed from plots to give periods of competition of 0, 2, 4, 6, 8, 10, and 25 weeks. Seed cotton yield was reduced 2 of 3 yr with full season (25 week) competition, but was unaffected by shorter periods of competition in all years. Main stem diameter of cotton was also reduced 2 of 3 yr when competing full season while main stem height was reduced in only 1 of 3 yr with full season competition. In the second series of experiments yellow nutsedge densities were monitored in 48 individual plots and regression analysis showed yields of seed cotton were consistently reduced with full-season competition. Yellow nutsedge shoot densities ranged from zero to 93 shoots/m2(measured 13 cm on either side of the drill) and approximately 18 kg/ha of seed cotton were lost for each additional yellow nutsedge plant per m2.
Longevity of Velvetleaf (Abutilon theophrasti) Seeds in Soil under Agricultural Practices
Authors: Lueschen William E. , Andersen Robert N.
Published: January 2018

A field experiment involving seven cultural practices was begun in 1974 in an area heavily infested with velvetleaf (Abutilon theophrastiMedic.) seed. Our objective was to determine the time required to eradicate velvetleaf seed from the soil. This paper reports the results of the first 4 yr of a long-term study. A cultural practice is repeated on the same plot year after year. Since the experiment was begun, no velvetleaf plants have been allowed to produce seed in any plots. The number of viable velvetleaf seeds is monitored by yearly soil sampling. In 1978, after 4 yr of a fallow treatment involving intensive tillage (two plowings per yr plus monthly tillage throughout the growing season), only 10% of the original seed population remained. However, that 10% was 1,300 viable seeds per m2(to a depth of 23 cm). Four other practices that involved tillage gave generally similar results. Under undisturbed, continuous alfalfa, 56% of the original seed population remained after 4 yr, and under undisturbed, continuous chemical fallow, 37% remained. The results thus far demonstrate the extreme difficulty of eradicating velvetleaf seeds from the soil, and generally agree with reports in the literature, which primarily include studies conducted under more artificial conditions than we used. Our results also suggest that, in soil, velvetleaf seeds that have become water permeable (nonhard) may later again become water impermeable (hard).
Inheritance of Flower Color in Musk Thistle (Carduus thoermeri)
Authors: McCarty M. K. , Gorz H. J. , Haskins F. A.
Published: January 2018

Four flower-color phenotypes were observed in a population of musk thistle (Carduus thoermeri Weinm.). This plant has been commonly referred to as C. nutans L. The four phenotypes were: purple corolla and purple pollen, pink corolla and white pollen, white corolla and purple pollen, and white corolla and white pollen. In four generations, 177 self-pollinated individuals of these four phenotypes produced 2123 progeny plants that were classified. Results support the hypothesis that three independent gene pairs were involved in determining the four flower phenotypes. The gene pairs have been designated P/p, W/w, and Pi/pi. It was postulated that all three dominant alleles, P, W, and Pi, must be present to produce both purple corollas and purple pollen. The p allele prevents color development in both corollas and pollen; the w allele eliminates color in corollas but does not affect pollen color; and the pi allele dilutes corolla color from purple to pink and eliminates pollen color. Height measurements of progenies of self-pollinated plants indicated that decreased plant height was associated with inbreeding. On the basis of the evidence presented, the musk thistle plants used in these experiments appear to belong to a single species.
Oxyfluorfen and Lipid Peroxidation: Protein Damage as a Phytotoxic Consequence
Authors: Kunert Karl J. , Homrighausen Carmen , Böhme Herbert , Böger Peter
Published: January 2018

Protein damage, as a primary phytotoxic consequence of in vivo lipid peroxidation, induced by the diphenyl ether herbicide oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene] at a concentration of 10 μM, was measured with the green algaScenedesmus acutus. In the light, water-soluble proteins are destroyed by a herbicide-induced peroxidation process that can be detected by production of fluorescent products and loss of specific amino acid residues of proteins. The water-soluble cytochrome c-553 and the membrane-bound cytochrome f-553, components of the photosynthetic electron transport, were specifically used as sensitive markers for protein damage, measured as decrease of redox reactions of the cytochromes. Under peroxidizing conditions, destruction of the algal cytochrome c is significantly higher than destruction of membrane-bound components, such as cytochrome f and chlorophyll. Protection against protein loss is achieved by the nonbiological antioxidant ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) or the photosynthesis inhibitor diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea].
Mode of Action Investigations with the Herbicides HOE-39866 and SC-0224
Authors: Bellinder Robin R. , Hatzios Kriton K. , Wilson Henry P.
Published: January 2018

In laboratory experiments, the effects of the herbicides HOE-39866 [ammonium (3-amino-3-carboxypropyl)-methylphosphinate] and SC-0224 (trimethylsulfonium carboxymethylaminomethylphosphonate) on the incorporation of NaH14CO3, [14C]-leucine, [14C]-uracil, and [14C]-acetate into enzymatically isolated soybean [Glycine max(L.) Merr. ‘Essex’] cells were evaluated to assess the activity of these herbicides on CO2fixation, protein, ribonucleic acid (RNA), and lipid syntheses. At low concentrations neither compound exhibited rapid or distinct inhibitions of any process as might be expected in the case of inhibition of a primary target site. Photosynthesis was the process least affected. At equimolar concentrations, protein and RNA syntheses were more sensitive to HOE-39866 than to SC-0224 while the reverse occurred in lipid synthesis. Protein synthesis appears to be a possible target site that may be involved in the herbicidal action of these two compounds.
Weed Interference with Cotton (Gossypium hirsutum). I. Buffalobur (Solanum rostratum)
Authors: Rushing Doug W. , Murray Don S. , Verhalen Laval M.
Published: January 2018

Cotton (Gossypium hirsutumL. ‘Westburn M’) was grown for 2 yr at two locations with full-season interference from buffalobur (Solanum rostratumDunal ♯ SOLCU) at densities ranging from 0 to 64 plants/10 m of row. Dry weight of buffalobur harvested increased by 0.063 to 0.303 kg/plot for each additional weed/10 m of row. Intraspecific competition among buffalobur plants was observed at the higher weed densities. Cotton plant height was reduced by 16 and 32 buffalobur plants/10 m of row (or more) at Tipton and Perkins, OK, respectively, when compared with cotton grown under weed-free conditions. The threshold densities at which initial lint yield reductions occurred were 8 buffalobur plants/10 m of row in 1982 and 1983 at Tipton and 32 and 2 plants/10 m of row at Perkins in 1982 and 1983, respectively. Lint yields were reduced curvilinearly from 6 to 18 kg/ha for each additional buffalobur plant/10 m of row. Fiber quality was not significantly influenced by weed density when analyzed over all experiments; however, 50% span length, uniformity index, and micronaire were adversely affected in some environments.
Weed Interference with Cotton (Gossypium Birsutum). II. Tumble Pigweed (Amaranthus Albus)
Authors: Rushing Doug W. , Murray Don S. , Verhalen Laval M.
Published: January 2018

Relationships between production of cotton (Gossypium birsutumL. ‘Westburn M’) and full-season interference from tumble pigweed (Amaranthus albusL. ♯ AMAAL) at densities ranging from 0 to 64 plants/10 m of row were measured in three replicated experiments in the field. Dry weight of harvested tumble pigweed increased by 0.149 to 0.402 kg/plot for each additional weed/10 m of row. Intraspecific competition among tumble pigweed plants was observed at the higher weed densities. Cotton plant height was reduced in all three experiments at the 32 or 64 weed densities, but harvesting difficulties were not encountered in these studies. The threshold density where initial lint yield reductions occurred ranged from 4 to 16 tumble pigweed plants/10 m of row in the three experiments. Lint yields were reduced from 8 to 11 kg/ha for each additional tumble pigweed plant/10 m of row. Interference from tumble pigweed did not significantly affect cotton fiber length, uniformity, strength, or micronaire of hand-harvested bolls.
Effects of Metolachlor Residues on Rice (Oryza sativa)
Authors: Braverman Michael P. , Lavy Terry L. , Talbert Ronald E.
Published: January 2018

Field studies were conducted on a Taloka silt loam (Mollic Albaqualf) to determine the effects of residual levels of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] on rice (Oryza sativaL.). Yield reductions could be overcome by increasing rice seeding rate, by decreasing seeding depth, or by applying the safeners CGA-43089 [α-(cyanomethoxyimino)-benzacetonitrile] or CGA-92194 [α-(1,3-dioxolan-2-yl-methoximino)-benzacetonitrile] to the rice seed. Greenhouse studies with the safeners and reduced seeding depths indicated that CGA-92194 was better than CGA-43089 for protecting rice from metolachlor injury, but reduced seeding depths did not reduce metolachlor injury.
Variability for Response to Herbicides in Wild Oat (Avena fatua) Populations
Authors: Thai Kiet M. , Jana Sakti , Naylor James M.
Published: January 2018

Reaction of some wild oat (Avena fatuaL. ♯4AVEFA) populations to the herbicide triallate [S-(2,3,3-trichloroallyl)diisopropylthiocarbamate] was investigated in a controlled-environment chamber. Under specified conditions, 1.0 mg active ingredient of triallate incorporated in 1 kg of soil was a satisfactory diagnostic rate for 14-day-old seedlings. Five seedling growth parameters were studied. These parameters were emergence, survival to produce first leaf, mesocotyl length, first-leaf length, and seedling height. Of these, mesocotyl length was least affected by triallate treatment, and significant differences in variability for triallate reaction were found within and among historically triallate unexposed, as well as exposed populations. Within-population variation for seedling emergence and survival was higher in unexposed than in exposed populations. Populations with recurrent exposure to triallate were more tolerant to the herbicide under experimental conditions than historically unexposed populations. Triallate-tolerant lines were identified which were tolerant to two other common wild oat herbicides.
Susceptibility of Bermudagrass (Cynodon dactylon) Biotypes to Several Herbicides
Authors: Bryson Charles T. , Wills Gene D.
Published: January 2018

Field experiments were conducted in 1982 and 1983 at Stoneville, MS, to determine the susceptibility of 17 biotypes of bermudagrass [Cynodon dactylon(L.) Pers. ♯ CYNDA] to seven postemergence herbicides. Control, averaged over all biotypes 13 weeks after treatment, varied from 96% using haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid} at 0.56 kg/ha to 16% using fenoxaprop {(±)-2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy]propanoic acid} at 0.28 kg/ha. Control among biotypes ranged from 89 to 96% using haloxyfop at 0.56 kg/ha and from 4 to 89% using dalapon (2,2-dichloropropanoic acid) at 11.2 kg/ha.
Potential Control of Weedy Spurges by the RustUromyces scutellatus
Authors: Défago Genevieve , Kern Heinz , Sedlar Ludmila
Published: January 2018

In a location with cypress spurge (Euphorbia cyparissiasL. ♯ EPHCY) and naturally occurringUromyces scutellatus(Pers.) Lév. s.str., the percent of shoots deformed by this systemic rust increased from 6% in 1981 to 48% in 1982, followed by a decrease in both deformed and normal shoots in 1983 and 1984. After inoculation in 1981 of two cypress spurge crowns at a location near Zürich by teliospores ofUromyces alpestrisTranzsch., more than 80% deformed shoots were obtained in 1983 and 1984. Inoculations of cypress spurge root segments byU. scutellatuss.str. orU. alpestrisin experimental plots in 1982 gave 50 to 100% infected plants, and in most cases more than 50% deformed shoots in 1984. The collection ofU. alpestrisstudied (E-52) could be a promising candidate for mycocontrol of cypress spurge because of its pathogenicity and specificity.
Adsorption, Mobility, and Efficacy of Metribuzin as Influenced by Soil Properties
Authors: Peter C. John , Weber Jerome B.
Published: January 2018

The effect of various soil parameters on metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] efficacy was studied on seven soils and metribuzin adsorption was investigated in nine soils. Soil organic-matter and clay contents were correlated with metribuzin activity. Specific surface area, as measured by ethylene glycol monoethyl ether (EGME) was highly correlated with metribuzin activity. Soil organic-matter content and EGME surface area measurements were also highly correlated with metribuzin adsorption in soils. Since metribuzin is highly water soluble (water solubility greater than 1000 ppm), it was probably adsorbed at the hydrophilic sites on the soil surfaces that were measured by EGME. Metribuzin was much more mobile than atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] in a leaching study.
Adsorption, Mobility, and Efficacy of Alachlor and Metolachlor as Influenced by Soil Properties
Authors: Peter C. John , Weber Jerome B.
Published: January 2018

Alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] adsorption was positively correlated with soil organic-matter content, clay content, and surface area as measured by ethylene glycol monoethyl ether (EGME) or benzyl ethyl ether (BEE) and inversely correlated with herbicidal activity. Alachlor was adsorbed in slightly greater amounts by soil than metolachlor. Metolachlor had slightly greater bioactivity than alachlor on grass weeds, but the herbicides had similar activity on broadleaf weeds. Slightly greater amounts of metolachlor than alachlor were leached through a Norfolk soil and slightly greater amounts of alachlor were retained in the upper soil zones, compared with metolachlor.