Entry Path Research Articles

Origin of carbon in agricultural soil profiles deduced from depth gradients of C:N ratios, carbon fractions, \u03b413C and \u03b415N values

AimsAgricultural soils in Germany store 2.54 Pg of organic carbon (C). However, information about how and when this C entered the soils is limited. This study illustrates how depth profiles of organic matter can shed light on different entry paths of organic C.MethodsMachine learning was used to explain total organic C (TOC), C:N, particulate organic C (POC), δ13C and δ15N values down to 100 cm depth based on pedology, geology, climate and management-related variables from the German Agricultural Soil Inventory. We estimated TOC turnover rates based on the relationship between the proportion of maize (only C4 plant) in crop rotations and soil δ13C values.ResultsIn the upper 30 cm of cropland, fresh photosynthates added on average 0.2 to 0.8 Mg C ha− 1 year− 1. Organic fertiliser was another source of topsoil C, especially in grassland. Sandy sites in north-west Germany contained historic C from past heathland and peatland. One third of German agricultural land was found to be on colluvial and alluvial deposits, in which allochthonous C from upstream and upslope areas evidently increased the TOC content of subsoils. In and below hardpans, TOC content and C:N and POC:TOC ratios were low, indicating restricted root-derived C input.ConclusionsOur data indicate that ongoing management in German agricultural soils mainly affects topsoil C, while C storage in subsoils reveals significant legacies from allochthonous, buried or translocated C inputs. Specific attention should be focused on the sustainable loosening of hardpans that could result in a slow, but significant increase in subsoil C stocks.

X‐Ray Crystallographic Analysis of NifB with a Full Complement of Clusters: Structural Insights into the Radical SAM‐Dependent Carbide Insertion During Nitrogenase Cofactor Assembly

AbstractNifB is an essential radical SAM enzyme required for the assembly of an 8Fe core of the nitrogenase cofactor. Herein, we report the X‐ray crystal structures of Methanobacterium thermoautotrophicum NifB without (apo MtNifB) and with (holo MtNifB) a full complement of three [Fe4S4] clusters. Both apo and holo MtNifB contain a partial TIM barrel core, but unlike apo MtNifB, holo MtNifB is fully assembled and competent in cofactor biosynthesis. The radical SAM (RS)‐cluster is coordinated by three Cys, and the adjacent K1‐ and K2‐clusters, representing the precursor to an 8Fe cofactor core, are each coordinated by one His and two Cys. Prediction of substrate channels, combined with in silico docking of SAM in holo MtNifB, suggests the binding of SAM between the RS‐ and K2‐clusters and putative paths for entry of SAM and exit of products of SAM cleavage, thereby providing important mechanistic insights into the radical SAM‐dependent carbide insertion concomitant with cofactor core formation.

X-Ray Crystallographic Analysis of NifB with a Full Complement of Clusters: Structural Insights into the Radical SAM-Dependent Carbide Insertion During Nitrogenase Cofactor Assembly.

NifB is an essential radical SAM enzyme required for the assembly of an 8Fe core of the nitrogenase cofactor. Herein, we report the X-ray crystal structures of Methanobacterium thermoautotrophicum NifB without (apo MtNifB) and with (holo MtNifB) a full complement of three [Fe4 S4 ] clusters. Both apo and holo MtNifB contain a partial TIM barrel core, but unlike apo MtNifB, holo MtNifB is fully assembled and competent in cofactor biosynthesis. The radical SAM (RS)-cluster is coordinated by three Cys, and the adjacent K1- and K2-clusters, representing the precursor to an 8Fe cofactor core, are each coordinated by one His and two Cys. Prediction of substrate channels, combined with in silico docking of SAM in holo MtNifB, suggests the binding of SAM between the RS- and K2-clusters and putative paths for entry of SAM and exit of products of SAM cleavage, thereby providing important mechanistic insights into the radical SAM-dependent carbide insertion concomitant with cofactor core formation.

Insect Bacterial Symbiont-Mediated Vitellogenin Uptake into Oocytes To Support Egg Development.

Many insect species, such as aphids, leafhoppers, planthoppers, and whiteflies harbor obligate bacterial symbionts that can be transovarially transmitted to offspring through the oocytes of female insects. Whether obligate bacterial symbionts can carry important molecules/resources to the embryos to support egg development is still unknown. Here, we show that the vitellogenin (Vg) precursor of rice leafhopper Nephotettix cincticeps is biosynthesized by the fat body, secreted into the hemolymph and subsequently cleaved into the 35- and 178-kDa subunits, whereas only the 178-kDa subunit is taken up by the leading end of oocytes in a receptor-dependent manner or moves into the posterior pole of the terminal oocyte in association with obligate bacterial symbiont "Candidatus Nasuia deltocephalinicola" (hereafter Nasuia) in a receptor-independent manner. Furthermore, the 178-kDa Vg subunit can directly interact with a surface channel molecule (porin) on the envelope of Nasuia, allowing Vg to enter bacterial cytoplasm. Thus, Vg can hitchhike the ancient oocyte entry path of Nasuia, the common obligate symbiont of leafhoppers. Knocking down a Nasuia growth-related protein expression or treatment with porin antibody strongly prevents the ability of Nasuia to carry Vgs into oocytes and impair insect egg development. Nasuia-carried Vgs provide at least 20% of the total Vgs in the developing eggs. We anticipate that the bacterial symbiont-mediated Vg uptake into oocytes to support efficient egg development may be a common pattern shared by many insects.IMPORTANCE Many insects harbor obligate bacterial symbionts that can be vertically transmitted to offspring by female insects through eggs. Here, we report that leafhopper vitellogenin (Vg) recognizes and binds a surface channel molecule (porin) on the envelope of obligate bacterial symbiont Nasuia, which potentially induces the opening of porin channels for Vg to access the cytoplasm of Nasuia Thus, Vg can exploit bacterial symbionts as the independent carriers into the oocytes. Such Nasuia-carried Vg contents support efficient insect egg development. Thus, our findings indicate that insects have evolved strategies to exploit the symbionts for carrying additional Vgs to guarantee optimal insect reproduction.

Plastic in compost: Prevalence and potential input into agricultural and horticultural soils

To maintain and improve soil fertility, compost application is a widely recommended practice. We hypothesized that this practice is, however, also a main entry path for plastic into soil. Hence, we i) quantified the prevalence of plastic in eight composts from different composting plants and hardware stores to derive estimations about related plastic inputs into soil, and ii) characterized the properties of these plastic residues in regard to size and shape for further risk assessment. Plastic remains were analyzed via density separation (ZnCl2) and light microscopy. Testing this method recovered 80 ± 29% of spiked plastic items. Applying this method revealed that all composts contained plastic particles in detectable amounts, with contents ranging from 12 ± 8 to 46 ± 8 particles kg−1, corresponding to calculated plastic weights of 0.05 ± 0.08 to 1.36 ± 0.59 g kg−1. Because of this high variability, an a-priori discrimination of plastic loads between compost types cannot be achieved. Upscaling these loads to common recommendations in composting practice, which range from 7 to 35 t compost ha−1, suggest that compost application to agricultural fields goes along with plastic loads of 84,000 to 1,610,000 plastic items ha−1 per year (a), respectively, amounting to 0.34 to 47.53 kg plastic ha−1 a−1. Large potential inputs should thus also occur for horticultural soils, where application rates of compost usually vary between 6.48 and 19.44 t ha−1, therewith resulting in a minimum plastic contamination of 77,770 plastic items and 0.31 kg plastic ha−1 a−1, but a maximum amount of up to 894,240 plastic items and 26.4 kg plastic ha−1 a−1. We conclude that compost application must be considered as potential source of plastic for both agricultural and horticultural soils, and technical solutions are needed to minimize these contamination risks while continuing this practice as important option to secure soil health.

Current level of oil hydrocarbons in Russian coastal waters of the Black Sea and and Azov Sea

Aim. Currently, oil pollution remains one of the primary pollutants of the marine environment. This is especially true for the Black Sea and Azov Sea which experience significant anthropogenic pressure. The study presents the results of two-year monitoring studies of the content of oil hydrocarbons in the surface and bottom horizons of the coastal waters of the Azov-Black Sea regions of Russia.Materials and Methods. The determination of oil hydrocarbons was conducted by infrared spectrometry using a FSM-1201 Fourier spectrophotometer with preliminary transmission of the extracts through a chromatographic column with aluminum oxide. The work was carried out as part of five scientific expeditions (93th, 96th, 100th, 102nd and 105th) of the research vessel, Professor Vodyanitsky, in 2017 and 2018.Results. The general environmental status for this pollutant is characterized as stable, despite in some cases being 3 to 4 times in excess of established standards (MPC). Separate foci of localized oil pollution have been identified and vulnerable areas of the sea coast of southern Russia have been identified. An excess content of petroleum hydrocarbons in the surface layer compared to the bottom layer was noted, which indicates a surface path of entry of petroleum products into sea water.Conclusion. Currently, the coastal waters of the western part of Crimea are most affected by oil, primarily associated with the runoff of European rivers and the peculiarities of the marine hydrological regime, including the Kerch Strait, an area of heavy shipping traffic. The Caucasian coast is less affected by oil pollution than the Crimean. Despite the fact that currently the content of oil hydrocarbons in sea water is far from the quantities dangerous to humans and aquatic organisms, monitoring of this indicator is vital due to the increasing anthropogenic pressure on the recreational zones of the Crimean and Caucasian coasts of the Russian Federation.

Aerodynamics of Orion in Rarefied Flow Along a Mars Entry Path

It is well known that the Orion capsule was born as a rescue shuttle for the International Space Station. NASA developed the Orion project for the transportation of instruments and astronauts to moon, Mars, and beyond. Orion is similar in shape but larger than the Apollo command module; Orion will be able to host up to six astronauts, but Apollo command module could host only three astronauts. The aerodynamics of Orion during reentry to Earth in all rarefied regimes (that is, from free molecule regime to continuum) was already studied. The forthcoming use of Orion for Mars landing stimulated the author to evaluate global aerodynamic coefficients in rarefied flow along an entry path. The study considered problems both in axisymmetric and in three-dimensional flows by means of two direct simulation Monte Carlo codes. Global aerodynamic coefficients were computed at the altitudes of 80, 90, and 100 km. Special attention was paid to longitudinal stability.

Characterization of a Rhodobacter sphaeroides primary fatty acid kinase.

Widely distributed among prokaryotes, short chain fatty acid kinases provide a path for fatty acid entry into central metabolic pathways. These enzymes catalyze the reversible, ATP-dependent synthesis of acyl-phosphates, which leads to the production of acyl-CoA derivatives by a coordinate acyltransferase. To date, characterized representatives of short chain fatty acid kinases exhibit relatively narrow substrate specificity. In this work, biochemical characterization of a predicted acetate kinase from Rhodobacter sphaeroides reveals a novel enzyme with broad substrate specificity for primary fatty acids of varying lengths (C2--C8).

Implementasi Fuzzy Tsukamoto dan IoT Pada Sistem Pendukung Keputusan Tingkat Kepadatan Lahan Parkir

Parking lots are a common thing in everyday life. The problem of parking lot's density can be a problem for managers of a place. So to overcome the problem that can occur, this study aims to design a decision support system (DSS) to determine the density of parking lots by applying the concept of IoT and Tsukamoto's fuzzy method. IoT is used to automate data retrieval to create fuzzy rule patterns. In the Tsukamoto method, each rule is represented by IF-THEN. The method for system design in this study includes the design of hardware and software. In this design, data retrieval uses an ultrasonic sensor HC-SR04 and is processed with the IoT concept using Arduino UNO and ESP8266 microcontrollers. The sensor is placed on the exit and entry path of the vehicle on the parking lot to detect vehicles entering and exiting. The parking lot used in this study is miniature. Vehicle data is processed using Tsukamoto's fuzzy logic to determine parking density decisions. Data variables used are time, duration, and density of parking lots. DSS is designed using the Laravel framework. Based on the test results, it is known that IoT devices can perform their functions properly. DSS that is made in the form of a website can also function well. The results are based on error testing, obtained error for determining the parking density level is 7,68%.

The Way of Macroplastic through the Environment

With the focus on microplastic in current research, macroplastic is often not further considered. Thus, this review paper is the first to analyse the entry paths, accumulation zones, and sinks of macroplastic in the aquatic, terrestrial, and atmospheric environment by presenting transport paths and concentrations in the environment as well as related risks. This is done by applying the Source–Pathway–Receptor model on macroplastic in the environment. Based on this model, the life cycle of macroplastic is structurally described, and knowledge gaps are identified. Hence, current research aspects on macroplastic as well as a sound delimitation between macro- and microplastic that can be applied to future research are indicated. The results can be used as basic information for further research and show a qualitative assessment of the impact of macroplastic that ends up in the environment and accumulates there. Furthermore, the applied model allows for the first time a quantitative and structured approach to macroplastic in the environment.

A Single-Cell RNA Expression Map of Human Coronavirus Entry Factors

To predict the tropism of human coronaviruses, we profile 28 SARS-CoV-2 and coronavirus-associated receptors and factors (SCARFs) using single-cell transcriptomics across various healthy human tissues. SCARFs include cellular factors both facilitating and restricting viral entry. Intestinal goblet cells, enterocytes, and kidney proximal tubule cells appear highly permissive to SARS-CoV-2, consistent with clinical data. Our analysis also predicts non-canonical entry paths for lung and brain infections. Spermatogonial cells and prostate endocrine cells also appear to be permissive to SARS-CoV-2 infection, suggesting male-specific vulnerabilities. Both pro- and anti-viral factors are highly expressed within the nasal epithelium, with potential age-dependent variation, predicting an important battleground for coronavirus infection. Our analysis also suggests that early embryonic and placental development are at moderate risk of infection. Lastly, SCARF expression appears broadly conserved across a subset of primate organs examined. Our study establishes a resource for investigations of coronavirus biology and pathology.

Tyre and road wear particles - A calculation of generation, transport and release to water and soil with special regard to German roads

Tyre and road wear is one of the main emission sources of particulate plastics (microplastics). In this study, the emissions of tyre wear particles (TWP) which are annually generated on the German road network were calculated. Emissions are calculated by applying two different data sets of emission factors and the annual mileage for distinct vehicles and road types (urban roads, rural roads, highways). Environmental entry paths of tyre and road wear particles (TRWP) were considered including releases to ambient air, soils and surface waters. Road runoff treatment was taken into account differentiated into sewage systems in urban areas and at non-urban roads. This study identifies the soundest data available concerning emission factors, data on traffic and road systems as well as comprehensive information on road runoff treatment in Germany. Applying this data and assuming that 5% of the total emissions are ‘fine’ air-borne particles, the emissions of coarse ‘non-airborne’ particles are 75,200–98,400 t/a; . the transport to road banks and soils near roads is 57,300–65,400 t/a (66–76%) including runoff and drift; 8700–19,800 t/a (12–20%) are released to surface waters. Due to lack of data, degradation in soils and surface waters was not considered. Besides soils, urban wastewater treatment plants are expected to be an important sink of TRWP assuming that most of the particles are incorporated in the sewage sludge. Due to the application of sewage sludge as a fertilizer, 1400–2800 t/a TWP are currently deposited on agricultural areas. No reliable data was available to estimate the masses of TWP which are transported from freshwaters into the marine environment. Existing mitigation measures should be improved according to the principle of precaution by installation of road runoff treatment systems and retrofitting of existing plants regarding optimum fine particle retention.

It's in the loop: shared sub-surface foot kinematics in birds and other dinosaurs shed light on a new dimension of fossil track diversity.

The feet of ground-dwelling birds retain many features of their dinosaurian ancestry. Experiments with living species offer insights into the complex interplay among anatomy, kinematics and substrate during the formation of Mesozoic footprints. However, a key aspect of the track-making process, sub-surface foot movement, is hindered by substrate opacity. Here, we use biplanar X-rays to image guineafowl walking through radiolucent substrates of different consistency (solid, dry granular, firm to semi-liquid muds). Despite substantial kinematic variation, the foot consistently moves in a looping pattern below ground. As the foot sinks and then withdraws, the claws of the three main toes create entry and exit paths in different locations. Sampling these paths at incremental horizons captures two-dimensional features just as fossil tracks do, allowing depth-based zones to be characterized by the presence and relative position of digit impressions. Examination of deep, penetrative tracks from the Early Jurassic confirms that bipeds had an equivalent looping response to soft substrates approximately 200 Ma. Our integration of extant and extinct evidence demonstrates the influence of substrate properties on sinking depth and sub-surface foot motion, both of which are significant sources of track variation in the fossil record of dinosaurs.

Microplastic analysis using chemical extraction followed by LC-UV analysis: a straightforward approach to determine PET content in environmental samples

BackgroundThe ubiquitous occurrence of microplastic particles in marine and aquatic ecosystems was intensively investigated in the past decade. However, we know less about the presence, fate, and input paths of microplastic in terrestrial ecosystems. A possible entry path for microplastic into terrestrial ecosystems is the agricultural application of sewage sludge and solid bio-waste as fertilizers. Microplastic contained in sewage sludge also includes polyethylene terephthalate (PET), which could originate as fiber from textile products or as a fragment from packaging products (foils, bottles, etc.). Information about microplastic content in such environmental samples is limited yet, as most of the used analytical methods are very time-consuming, regarding sample preparation and detection, require sophisticated analytical tools and eventually need high user knowledge.ResultsHere, we present a simple, specific tool for the analysis of PET microplastic particles based on alkaline extraction of PET from the environmental matrix and subsequent determination of the monomers, terephthalic acid, using liquid chromatography with UV detection (LC-UV). The applicability of the method is shown for different types of PET in several soil-related, terrestrial environmental samples, e.g., soil, sediment, compost, fermentation residues, but also sewage sludge, suspended particles from urban water management systems, and indoor dust. Recoveries for model samples are between 94.5 and 107.1%. Limit of determination and limit of quantification are absolute masses of 0.031 and 0.121 mg PET, respectively. In order to verify the measured mass contents of the environmental samples, a method comparison with thermal extraction-desorption-gas chromatography–mass spectrometry (TED-GC/MS) was conducted. Both methods deliver similar results and corroborated each other. PET mass contents in environmental samples range from values below LOQ in agriculture soil up to 57,000 mg kg−1 in dust samples.ConclusionsWe demonstrate the potential of an integral method based on chemical extraction for the determination of PET mass contents in solid environmental samples. The method was successfully applied to various matrices and may serve as an analytical tool for further investigations of PET-based microplastic in terrestrial ecosystems.

Endocytosis and the internalization of pathogenic organisms: focus on phosphoinositides.

Despite their comparatively low abundance in biological membranes, phosphoinositides are key to the regulation of a diverse array of signaling pathways and direct membrane traffic. The role of phosphoinositides in the initiation and progression of endocytic pathways has been studied in considerable depth. Recent advances have revealed that distinct phosphoinositide species feature prominently in clathrin-dependent and -independent endocytosis as well as in phagocytosis and macropinocytosis. Moreover, a variety of intracellular and cell-associated pathogens have developed strategies to commandeer host cell phosphoinositide metabolism to gain entry and/or metabolic advantage, thereby promoting their survival and proliferation. Here, we briefly survey the current knowledge on the involvement of phosphoinositides in endocytosis, phagocytosis, and macropinocytosis and highlight several examples of molecular mimicry employed by pathogens to either “hitch a ride” on endocytic pathways endogenous to the host or create an entry path of their own.

Imitación creativa frente a las oportunidades de la farmabiotecnología

En este artículo se analiza la experiencia de ascenso industrial de Corea del Sur y la India en la industria biofarmacéutica mundial. A partir de un abordaje histórico comparativo, se analiza cómo durante los últimos años y ante el escenario de expiración de las patentes de los productos farmacéuticos de mayor complejidad, estos dos países lograron avanzar en procesos de industrialización “muy tardíos” a partir del desarrollo de una estrategia de imitación creativa. Se indaga, en particular, cómo estos países siguieron trayectorias diferenciadas de entrada: por un lado, la de “salto de etapas”, que demandó un conjunto de acciones deliberadas orientadas a favorecer a ciertas actividades o sectores de una forma focalizada; por otro, la de tipo secuencial, en la que los cambios institucionales y de política fueron más graduales, asegurando un conjunto de condiciones generales de infraestructura tecnológica y propiedad intelectual.

Evaluation of student academic performance using e-learning with the association rules method and the importance of performance analysis

In managing the student study process, there is a pattern that occurs repeatedly every year. The recurring data will produce information in the form of student profiles, entry paths, student academic results, study period, average graduate-level and much other information as long as students take the process of teaching and learning activities. This research was conducted to predict student performance and e-learning satisfaction at the Computer Science department in Mulawarman University using the Association Rules method and Importance Performance Analysis. The sample in this study was 389 data of computer science graduate students. Based on the results of the research that has been done, it can be concluded that the graduation rate of computer science students of the Faculty of Computer Science and Information Technology, as follows; students who have graduated most have a GPA interval of 2.76 - 3.50 with male gender and take a study period of more than 6 years which has a support value of 0.321 and a confidence value of 0.628. Their perception of e-learning according to IPA coordinates community, collaboration, materials, social media, knowledge, synthesis, application, understanding, multimedia, evaluation, video, and news in quadrant II has a high level of importance with a relatively high level of performance and must be maintained.

Market entry strategies in a high-tech successive generations market: a case study of three semiconductor firms with different entry modes

PurposeThe purpose of this study is to explore market entry strategies in a high-tech successive generations (HTSGs) market, by investigating entry mode via entry timing and path differentiation and the performance outcomes of entry mode.Design/methodology/approachThe methodology of building a theory from a longitudinal case study is adopted by using useful cases in a HTSGs market after constructing an integrated research framework to explore market entry mode. Different entry modes were investigated by studying entry timing and migration path of three firms’ case in logic semiconductor market. In addition, performance outcomes of different entry modes were measured and correlated with each other.FindingsThe results identified three major entry modes suitable for a HTSGs market. The three firms differentiated their entry modes by exploiting different entry timings from the earliest to the last and different migration paths including switching, leapfrogging and new entrance path to enter a market. First mover advantage also exists in a HTSGs market, and it was found uniquely that the financial performance denoted by entry mode outcomes was correlated with technological knowledge.Research limitations/implicationsThis study extends the theory of extant entry strategy from general consumer or industrial market to HTSGs market, in which intense competition exits and technological innovation is important. Moreover, this study verified that the causality between early entry and positive performance was also effective in HTSGs market with a shorter duration of early entry advantage.Practical implicationsThis study has managerial implications for firms to establish market entry strategy in HTSGs market and other markets. To become a product leader, a fast follower or a late follower, firms can differentiate their entry mode by adjusting the entry timing and migration path in the context of market and technology.Originality/valueThis study examined market entry strategies suitable for HTSGs market based on its unique characteristics and extended relevant theory into HTSGs market. Further, an integrated research framework, which explores the market entry mode, was constructed to facilitate further exploration of entry mode into other markets.

Identifying atmospheric river events and their paths into Iran

Atmospheric rivers (ARs), as narrow, dense water vapour paths, play a major role in transferring large volumes of atmospheric humidity compared to their surrounding areas. Accordingly, ARs have significant effects on the atmospheric water cycle and climatic conditions. They are more remarkable in arid and semi-arid regions due to the priority of water resources management and weather extreme effects. This study identified ARs entering Iran as well as their movement paths and synoptic factors affecting their determination. To this end, integrated water vapour transport data was applied to identify ARs for 2007–2018 (November to April). In general, 364 AR events were identified. The results showed that approximately 52% of ARs were directly originated from the Gulf of Aden and the Red Sea. It was also observed that ARs entered Iran from different paths. By classifying entry paths in terms of location and after conducting synoptic analysis for each path, it was found that the westward or eastward displacement of the Arabian subtropical anticyclone (ASA) and along with the extension pattern of Mediterranean trough was highly important in determining AR paths in the region. Moreover, about 67% of ARs entered the country from south and southwest, respectively, and the highest frequency was in January followed by March.

The path from geology to indoor radon

It is generally accepted that radon emission is strongly influenced by the geological characteristics of the bedrock. However, transport in-soil and entry paths indoors are defined by other factors such as permeability, building and architectural features, ventilation, occupation patterns, etc. The purpose of this paper is to analyze the contribution of each parameter, from natural to man-made, on the radon accumulation indoors and to assess potential patterns, based on 100 case studies in Romania. The study pointed out that the geological foundation can provide a reasonable explanation for the majority of the values recorded in both soil and indoor air. Results also showed that older houses, built with earth-based materials, are highly permeable to soil radon. Energy-efficient houses, on the other hand, have a tendency to disregard the radon potential of the geological foundation, causing a higher predisposition to radon accumulation indoors and decreasing the general indoor air quality.