bluuebunny/crossref_metadata_2025 huggingface dataset:
Features of CU and MN accumulation by bottom sediments of the Caspian Sea
Authors: Ershova T S , Chaplygin V A , Zaitsev V F , Khursanov A S
Published: April 2021

The main sources of chemical elements for aquatic organisms are sea water and bottom sediments, and the levels of chemical elements in organisms depend on the level of these elements in the environment. The Caspian Sea is a special biogeochemical province with geochemical barriers in the area of mixing of river and sea waters, therefore, the study of its biogeochemical background, the peculiarities of the chemical composition of bottom sediments is the relevance of the work. The aim of this work was to reveal the content of manganese and copper in the bottom sediments of the Caspian Sea. The study revealed low concentrations of copper and relatively high manganese in the bottom sediments of the Caspian Sea, which is primarily due to the parent rocks of the Caspian lowland, which are poor in Cu, but rich in Mn. The results of biogeochemical analysis of bottom sediments of the ecosystem of the Caspian Sea serve as material for resolving the issue of the role of biogenic transformation of microelements in the cycle of substances.
Environmental Consequences of Recreational Vehicle Impact
Authors: Tcyplakova E G , Sinko G I , Purina N M , Yankevich Yu G , Yankevich K A
Published: April 2021

The article analyzes the environmental problems of recreational areas caused by the impact of road transport. In modern agglomerations, the load on recreational zones is increasing, which leads to a deterioration of the ecological situation in them. The most important factor affecting the environment is motor vehicles, the number of which is constantly growing. The article presents the main aspects of the recreational impact of vehicles and the factors of human activity that aggravate it. A survey of car owners allows us to draw conclusions about the irresponsible and sometimes predatory attitude towards nature of a large number of vacationers in the popular recreational areas of the Leningrad Region. The results obtained allow us to draw conclusions about the lack of awareness of the respondents and the unsatisfactory state of environmental awareness and education in our society, the lack of the necessary infrastructure for environmentally friendly recreation of the population.
Sulphur dioxide content in soils in the zone of influence of Severonickel plant in Murmansk region of the Russian Federation
Authors: Evseev A V , Vorobyevskaya E L , Kirillov S N , Mazurova A D , Tsymbal M N
Published: April 2021

Anthropogenic air pollution attracts attention of scientists and the public around the world for many years. Traveling over vast distances, particles and aerosols pollute the environment many kilometers away from emission sources. Primary anthropogenic aerosols enter the air mainly with industrial emissions from factories. Secondly aerosols are formed in the atmosphere through various physical and chemical processes involving water vapor, organic compounds, etc. This group includes sulphur dioxide. The article discusses issues related to the pollution of the environment as a result of the activities of the copper-nickel plant Severonickel, located on the Kola Peninsula. In particular, the problem of accumulation of sulfur compounds in the soil, which occurs over decades at a different distance from the industrial factory. Sulphur dioxide is a toxic substance, at high concentrations in the air there is a harmful impact on living organisms, precipitation leads to acidification of the soil, disturbance of soil and vegetation cover, changes balance and destroy ecosystems. For this reason, it is important to monitor the condition of ecosystems that are under the influence of industrial plants. This issue is dedicated to the work of researchers and students of the Department of Environmental Management of the Faculty of Geography of Lomonosov Moscow State University, who for more than twenty years have been monitoring the state of ecosystems in the impact zone of Severonickel plant, including a number of studies devoted to pollution of the soil with sulfur compounds.
Ensuring environmental cleanliness and technosphere safety of electrochemical production
Authors: Vinogradov O S , Vinogradova N A , Kachan O B , Bochkareva L P , Nazarova O M
Published: April 2021

The article discusses the possibility of reducing the volume of wastewater from electrochemical shops that produce metal coating by electrolysis. Due to the complexity of wastewater treatment from an entire enterprise, the possibility of local return of valuable components to the very process in which they were lost is being considered. Possible ways of returning metal ions that have entered the wastewater back into the technological cycle are shown. The software for calculating the necessary equipment for the implementation of the most closed water circulation cycle is proposed. The author’s software greatly simplifies the choice of the type of flushing and makes it possible to choose the best option for performing the necessary actions. It is possible to combine different types of washing baths and traps not only for environmental reasons, but also for economic reasons.
Toxic effects of Tween-80 and its mixtures with oil on oligochaetes
Authors: Zyuzina K D , Gelman M M , Zhdanova G O , Kupchinsky A B , Stom D I
Published: April 2021

This study investigates the toxicity of the nonionic surfactant Tween-80, both its pure form and mixtures with oil, against the Baikal oligochaetes Mesenchytraeus bungei Michaelsen, 1901. It was experimentally shown that mixtures of the surfactant under study and oil have a toxic effect on oligochaetes at concentrations, at which the action of individual substances is harmless. In addition, this negative effect intensifies with an increase in the concentration of both the surfactant and oil in the mixtures.
Streamer discharge generator in water treatment system
Authors: Sisoev V S , Zavyalova A A , Makalsky L M , Kuchno A V
Published: April 2021

The article shows the possibility of using an avalanche-streamer discharge with a low-temperature plasma to remove such contaminants as petroleum products and metal ions from water. These pollutants are characteristic of the waters present in the technological cycle of energy enterprises. The scheme of a unique experimental stand is given. The importance of the operating parameters of the generator used in the discharge unit for the effective implementation of the cleaning process is indicated.
Uralsk municipal solid waste disposal
Authors: Bulekova A A , Murzashev T K , Gubasheva B E , Gabdullina S M
Published: April 2021

Currently, there is an increase in household waste due to the large population growth. To effectively manage the generation of solid domestic waste, it is necessary to know the rate of waste generation and their composition. According to these parameters, the test site of the city of Uralsk was investigated. The study proposed alternative solutions to the problem of solid waste disposal using new technologies.
Greening of business activities in the E-7 and G-7 countries as a vector for improving their environmental safety
Authors: Medvedkina Y A , Khodochenko A V , Fedko N V
Published: April 2021

The research paper discusses the importance of using the environmental safety for the global economy. The article describes the impact of greening of business processes on the environmental safety. The study analyzes the implementation of greening of business activities in such groups of countries as E-7 and G-7. The paper presents the results of a cluster analysis of the features of environmental safety in the E-7 and G-7 countries.
Geology of minerals of the Tevlinsko-Russinskoe deposit
Authors: Almukhametova E M , Valeev A I , Gabdrakhmanov N Kh
Published: April 2021

The territory of the Tevlinsko-Russinskoe field is characterized by instability of the thermodynamic equilibrium of the geological environment, due to the existence of permafrost. The article considers the geological section of the region, its oil and gas content, analyzed the geological and physical information. The main technological solutions of the project document of the Tevlinsko-Russinskoe field are considered. Oil and gas content within the Urengoysky oil and gas region is established in a wide stratigraphic range. Tectonic screens, the presence of which is confirmed by the history of the field, complicate almost all deposits.
The efficiency of using a combined solar plant for the heat and humidity treatment of air
Authors: Aliyarova Lola Abdijabborovna , Uzakov Gulom Norboevich , Toshmamatov Bobir Mansurovich
Published: April 2021

The authors of this work have proposed a combined solar heating unit for the heat and humidity treatment of greenhouse air supplies. The object of research is a combined solar collector for the simultaneous heating of water and air. The heat and humidity treatment of supply air is an energy-intensive technological process that requires a very large consumption of thermal energy and water resources. For the operation of such a system, electric heating installations are often used; however, these systems are not always available and economical. In this paper, to reduce the consumption of traditional energy for the heat treatment of the air supply, a combined solar collector is proposed, and the results of an experimental study of the operating modes of the installation in the conditions of the city of Karshi are presented. It has been developed combined solar collector, the temperature of the heat carriers at the outlet in the heating mode “water + air” reached up to 48 °C (air) and up to 60 °C (water), which are acceptable for air treatment systems of heat and humidity in greenhouses. As a result of the experimental studies, the high energy efficiency of the combined solar collector in the “water + air” heating mode is shown. It has been established that the efficiency of the installation is in the range of 0.45 - 0.69.
Impact factory assessment on the air on the Pekhorka river basin
Authors: Novikov A V , Shiryaeva M A , Sumarukova O V , Lagutina N V , Barsukova M V
Published: April 2021

The background ecological situation on Pekhorka river of the Balashikha district is determined by its location in the eastern part of the Moscow agglomeration. Most of the neighboring industrial centers are located to the west of it, from the side of the prevailing winds. Enterprises harm the air state during construction works. The vast majority of the enterprises are concentrated on the territory of Balashikha. The article discusses an example of calculating air pollution from the enterprise influencing the environmental pollution on the river Pekhorka basin. Air samples were taken and data on emissions of substances into the atmosphere were obtained. The calculation of the impact of the enterprise on atmosphere pollution was carried out with a specialized program. As a result, calculation of the dispersion of pollutants concentrations were carried out, the schematic map of the concentrations of substances nitrogen dioxide and sulfur dioxide was created and measurs for the state of atmospheric air were suggested. Studies had shown that substances’ emissions slightly exceed the MPC and or did not exceed the MPC at all. However, it was necessary to carry out the regular atmosphere state monitoring to prevent damage to the environment.
Electricity metering in power supply systems with grid-connected solar power plants
Authors: Leshtayev O V , Stushkina N A , Zaginaylov V I
Published: April 2021

The article discusses the experience of using an induction meter of electrical energy in power supply systems with a network solar power plant connected in parallel to the centralized network. Amendments to Federal Law No. 35-FZ “On the Electricity Industry” of December 27, 2019, which determine the relevance of the construction and operation of grid solar power plants in Russia, have been studied. The block diagram of an experimental solar power plant (SPP) is presented. An experimental network solar power plant has been developed and tested, which makes it possible to assess the possibility of using this type of power plant in rural areas of the central Chernozem region, in a private courtyard. The calculation of the characteristics and the selection of brands of the main components used in the installation of the station, including an induction meter of electric energy, were made. The authors analyzed the consumption of electrical energy from a centralized electrical network without using a solar power plant and during its operation according to the readings of an electric meter. On the basis of the analysis carried out, conclusions were drawn about the reduction of electricity consumption from the centralized network during the operation of a network solar power plant. The operating modes of the electricity meter generated by the solar power plant, the consumption of electricity from the centralized network and the load of the consumer of electrical energy are described mathematically. The relationship between the direction of the current flowing through the counter, the magnetic fluxes induced on the counter disk and the direction of rotation of the disk is described on the basis of mathematical relationships. The authors draw conclusions about the possibility of using induction meters of electrical energy in parallel operation of solar power plants with a centralized network as devices for offsetting consumed and supplied electricity to the network.
Concerning the issue of resource assessment for solar energy utilization systems in the climatic conditions of the Russian Federation
Authors: Kurasov I S , Shchukina T V , Chudinov D M , Kononova M S , Mershchiev A A
Published: April 2021

The article deals with the distribution of the energy potential of solar radiation in the territory of the Russian Federation. The spatio-temporal regularities are revealed, which make it possible to assess the resource provision of engineering systems in a given renewable energy source. Graphical distributions of solar radiation for the northern latitudes of the Russian Federation, including the energy irradiance of vertical orientation surfaces by cardinal directions, are constructed. Equations are obtained for the possibilities of solar radiation depending on the considered month and latitude of the area. An amendment has been introduced that takes into account the decrease in the radiation intensity with average cloud cover for the regions. Revealed the territorial-temporal variability of the possibility of solar radiation, which makes it possible to assess the prospects of using or another system of utilization of radiation.
Role of the coal industry in regional sustainability of Krasnoyarsk Region
Authors: Savin O I , Makarchuk I Y , Savina E V , Panchenko V Y , Stupina A A , Petrov M A
Published: April 2021

This study is an attempt to analyze the prospects for the sustainable development of the coal industry in the Krasnoyarsk Region of Russia. The authors examined several important milestones in the formation of the industry and revealed some major issues, which hinder the development of the coal industry in Krasnoyarsk Region. This paper also evaluates the current state of the coal industry and discusses the plans for its further development from an economic and environmental point of view.
Modeling of sea currents and the spread of an oil slick in the Labrador Sea area
Authors: Martyn I , Petrov Y , Stepanov S , Sidorenko A
Published: April 2021

The article discusses the modeling of an oil spill in the Labrador Sea region using the Cardinal software package. The capabilities of the software package are shown. The use of a rectangular and curvilinear grid is presented, and the calculation of currents and spread of an oil slick is carried out under the condition of topographic irregularities of the sea bottom, the field of currents and wind conditions. As a result of the work, maps of the current field and sea level were obtained. The parameters of the oil spill were calculated, including the volume of dispersed and evaporated oil. And in conclusion, the transformation of an oil spill in the center of the sea for 5 days is shown.
Assessment and prospects of biogas use
Authors: Razinkov M I , Zhukova A A , Jovanovich S , Sorokin D E , Saidmurodova M A , Abramov V L , Novikova O V , Afanasyev Valentin Ya
Published: April 2021

This article reveals the relevance of the use and development of an alternative source of heat and power supply, which is biogas. The potential of such a clean energy source is very great. The demand of countries for biogas is different, but it is constantly increasing every year. It opens up a platform for a variety of services that depend on economic and political priorities. Biogas can provide energy and heat as well as clean cooking fuels to get rid of traditional energy sources. Biogas production solves the problem of growing volumes of organic waste, which contributes to the reduction of global greenhouse gas emissions.
Feeling Fit for Function: Haptic Touch and Aesthetic Experience
Authors: Roberts Tom
Published: April 2021

Traditionally, the sense of touch—alongside the senses of taste and smell—has been excluded from the aesthetic domain. These proximal modalities are thought to deliver only sensory pleasures, not the complex, world-directed perceptual states that characterize aesthetic experience. In this paper, I argue that this tradition fails to recognize the perceptual possibilities of haptic touch, which allows us to experience properties of the objects with which we make bodily contact, including their weight, shape, solidity, elasticity, and smoothness. These features, moreover, may be indicative of how well-suited an object is for its function, and in feeling them we can thus feel the positive aesthetic quality of functional beauty.
Use, Safety Assessment, and Implementation of Two Point-of-Care Tests for COVID-19 Testing
Authors: Hahn Megan , Olsen Aaron , Stokes Kindra , Fowler Randal C , Gu Rui , Semple-Lytch Shellanne , DeVito Andrea , Kurpiel Philip , Hughes Scott , Rakeman Jennifer L
Published: April 2021

Objectives

The Abbot ID NOW COVID-19 assay and Quidel Sofia 2 SARS Antigen FIA are point-of-care assays that offer rapid testing for severe acute respiratory syndrome coronavirus 2 viral RNA and nucleocapsid protein, respectively. Given the utility of these devices in the field, we investigated the feasibility and safety of using the ID NOW and Sofia assays in the public health response to the coronavirus disease 2019 pandemic and in future public health emergencies.

Methods

A combination of utilization and contamination testing in addition to a review of instrument workflows was conducted.

Results

Utilization testing demonstrated that both tests are intuitive, associated with high user test success (85%) in our study, and could be implemented by staff after minimal training. Contamination tests revealed potential biosafety concerns due to the open design of the ID NOW instrument and the transfer mechanisms with the Sofia. When comparing the workflow of the ID NOW and the Sofia, we found that the ID NOW was more user-friendly and that the transfer technology reduces the chance of contamination.

Conclusions

The ID NOW, Sofia, and other emerging point-of-care tests should be used only after careful consideration of testing workflow, biosafety risk mitigations, and appropriate staff training.
Albuminuria Intensifies the Link Between Urinary Sodium Excretion and Central Pulse Pressure in the General Population: The Wakuya Study
Authors: Tagawa Kaname , Tsuru Yusuke , Yokoi Katsumi , Aonuma Takanori , Hashimoto Junichiro
Published: April 2021

BACKGROUND

Central pulse pressure (cPP) is responsible for the hemodynamics of vital organs, and monitoring this parameter is important for cardiovascular disease (CVD) prevention. Excess sodium intake and (micro)albuminuria (a manifestation of renal microvascular damage) are known to be strong predictors of CVD. We sought to investigate the cross-sectional relationships among dietary sodium intake, albuminuria, and cPP in a general population cohort.

METHODS

The subjects were 933 apparently healthy adults (mean age, 56 ± 10 years). Radial pressure waveforms were recorded with applanation tonometry to estimate mean arterial pressure (MAP), cPP, forward and backward pressure amplitudes, and augmentation index. The urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples.

RESULTS

Both the urinary sodium/creatinine and albumin/creatinine ratios were positively correlated with cPP, even after adjusting for MAP (P < 0.001). Moreover, both ratios had a synergistic influence on increasing the cPP independent of age, sex, estimated glomerular filtration rate, hyperlipidemia, and diabetes (interaction P = 0.04). A similar synergistic influence was found on the forward pressure amplitude, but not on the backward pressure amplitude or augmentation index. The overall results were not altered when the urinary albumin/creatinine ratio was replaced with the existence of chronic kidney disease (CKD).

CONCLUSIONS

(Micro)albuminuria strengthens the positive association between urinary sodium excretion and cPP and systolic forward pressure. Excess sodium intake may magnify the cardiovascular risk by widening the aortic pulsatile pressure, particularly in the presence of concomitant CKD.
Does brain size affect mate choice? An experimental examination in pygmy halfbeaks
Authors: McNeil Rebecca M , Devigili Alessandro , Kolm Niclas , Fitzpatrick John L
Published: April 2021

Choosing a mate is one of the most important decisions in an animal’s lifetime. Female mate choice is often guided by the presence or intensity of male sexual ornaments, which must be integrated and compared among potential mates. Individuals with greater cognitive abilities may be better at evaluating and comparing sexual ornaments, even when the difference in ornaments is small. While brain size is often used as a proxy for cognitive ability, its effect on mate choice has rarely been investigated. Here, we investigate the effect of brain size on mate preferences in the pygmy halfbeak Dermogenys collettei, a small freshwater fish that forms mixed-sex shoals where mating takes place. Pygmy halfbeaks are ideal models as their semi-transparent heads allow for external brain measurements. After validating the use of external measurements as a proxy for internal brain size, we presented females with large or small brains (relative to body length) with two males that had either a large or small difference in sexual ornamentation (measured by the total area of red coloration). Unexpectedly, neither total relative brain size nor relative telencephalon size affected any measured aspect of mate preference. However, the difference in male sexual ornamentation did affect preference, with females preferring males with a smaller area of red coloration when the difference in ornaments was large. This study highlights the complexities of mate choice and the importance of considering a range of stimuli when examining mate preferences.
Resolving diverse protein–DNA footprints from exonuclease-based ChIP experiments
Authors: Biswas Anushua , Narlikar Leelavati
Published: April 2021

Motivation

High-throughput chromatin immunoprecipitation (ChIP) sequencing-based assays capture genomic regions associated with the profiled transcription factor (TF). ChIP-exo is a modified protocol, which uses lambda exonuclease to digest DNA close to the TF-DNA complex, in order to improve on the positional resolution of the TF-DNA contact. Because the digestion occurs in the 5′–3′ orientation, the protocol produces directional footprints close to the complex, on both sides of the double stranded DNA. Like all ChIP-based methods, ChIP-exo reports a mixture of different regions associated with the TF: those bound directly to the TF as well as via intermediaries. However, the distribution of footprints are likely to be indicative of the complex forming at the DNA.

Results

We present ExoDiversity, which uses a model-based framework to learn a joint distribution over footprints and motifs, thus resolving the mixture of ChIP-exo footprints into diverse binding modes. It uses no prior motif or TF information and automatically learns the number of different modes from the data. We show its application on a wide range of TFs and organisms/cell-types. Because its goal is to explain the complete set of reported regions, it is able to identify co-factor TF motifs that appear in a small fraction of the dataset. Further, ExoDiversity discovers small nucleotide variations within and outside canonical motifs, which co-occur with variations in footprints, suggesting that the TF-DNA structural configuration at those regions is likely to be different. Finally, we show that detected modes have specific DNA shape features and conservation signals, giving insights into the structure and function of the putative TF-DNA complexes.

Availability and implementation

The code for ExoDiversity is available on https://github.com/NarlikarLab/exoDIVERSITY.

Supplementary information

Supplementary data are available at Bioinformatics online.
Tolerability of Cefazolin in Nafcillin-Intolerant Patients for the Treatment of Methicillin-Susceptible Staphylococcus aureus Infections
Authors: Gandhi Ankit M , Shah Megan D , Donohue Lindsay E , Cox Heather L , Eby Joshua C
Published: April 2021

Background

Non-immunoglobulin E (IgE)-mediated hypersensitivity reactions (HSRs) to nafcillin are commonly reported, but scarce data are available to guide appropriate antibiotic change following these reactions. Although cefazolin is an attractive therapeutic alternative in methicillin-susceptible Staphylococcus aureus (MSSA) infections when patients experience an HSR to nafcillin, more data are needed to evaluate the tolerability of cefazolin after switching from nafcillin. The purpose of this study was to describe the tolerability of cefazolin in patients who develop a suspected non-IgE-mediated HSR to nafcillin.

Methods

This was a retrospective, descriptive case series of patients who received nafcillin for an MSSA infection, experienced a suspected non-IgE-mediated HSR, and were switched to cefazolin between October 2015 and November 2019 at a single academic medical center. The primary objective was to identify the percentage of patients who completed cefazolin after experiencing a suspected non-IgE-mediated HSR to nafcillin.

Results

There were 80 patients with 87 prespecified non-IgE-mediated HSRs during the study period. Seventy-one (89%) patients completed cefazolin, with 53 (75%) of these patients completing at least 2 weeks of therapy. One patient was ultimately switched from cefazolin to daptomycin due to concern for treatment failure. Eight patients (10%) did not tolerate cefazolin after switching from nafcillin. Of these, 3 patients experienced an unrelated HSR, whereas 5 patients experienced the same non-IgE-mediated HSR that was attributed to nafcillin and discontinued cefazolin within 7 days. The most common HSR cited was immune-mediated nephritis; however, the majority were clinically presumed but did not meet objective diagnostic criteria.

Conclusions

Treatment with cefazolin after experiencing a suspected non-IgE-mediated HSR to nafcillin appears to be safe, even for patients requiring a prolonged duration of cefazolin.
Changes in Emergency Medical Services Before and During the COVID-19 Pandemic in the United States, January 2018–December 2020
Authors: Handberry Maya , Bull-Otterson Lara , Dai Mengtao , Mann N Clay , Chaney Eric , Ratto Jeff , Horiuchi Kalanthe , Siza Charlene , Kulkarni Aniket , Gundlapalli Adi V , Boehmer Tegan K
Published: April 2021

Background

As a result of the continuing surge of coronavirus disease 2019 (COVID-19), many patients have delayed or missed routine screening and preventive services. Medical conditions, such as coronary heart disease, mental health issues, and substance use disorder, may be identified later, leading to increases in patient morbidity and mortality.

Methods

National Emergency Medical Services Information System data were used to assess 911 emergency medical services (EMS) activations during 2018–2020. For specific activation types, the percentage of total activations was calculated per week, and Joinpoint analysis was used to identify changes over time.

Results

Since March 2020, the number of 911 EMS activations has decreased, while the percentages of on-scene death, cardiac arrest, and opioid use/overdose EMS activations were higher than prepandemic levels. During the early pandemic period, percentages of total EMS activations increased for on-scene death (from 1.3% to 2.4% during weeks 11–15), cardiac arrest (from 1.3% to 2.2% during weeks 11–15), and opioid use/overdose (from 0.6% to 1.1% during weeks 8–18). The percentages then declined but remained above prepandemic levels through calendar week 52.

Conclusions

The COVID-19 pandemic has indirect consequences, such as relative increases in EMS activations for cardiac events and opioid use/overdose, possibly linked to disruptions is healthcare access and health-seeking behaviors. Increasing telehealth visits and other opportunities for patient–provider touch points for chronic disease and substance use disorders that emphasize counseling, preventive care, and expanded access to medications can disrupt delayed care-seeking during the pandemic and potentially prevent premature death.
Heparin-free regional anticoagulation of haemodialysis filters with calcium-free dialysate: is citrate mandatory?
Authors: Medrano Chloé , Cointault Olivier , Lavayssiere Laurence , Nogier Marie-Béatrice , Colliou Eloïse , Setbon Nicolas , Kamar Nassim , Faguer Stanislas
Published: April 2021

Background

There is an unmet need to develop safe and successful heparin-free regional anticoagulation modalities in haemodialysed patients at risk of bleeding. Whether the addition of citrate as a prefilter injection or in the dialysate itself is required to reach anticoagulation objectives when calcium-free dialysate is used as regional anticoagulation remains unclear.

Methods

In this monocentric retrospective study, we report our experience of 908 dialysis sessions performed with a calcium-free citrate-containing dialysate and calcium reinjection according to the ionic dialysance, without additional heparin.

Results

Premature termination for filter clotting occurred in 20 sessions (2.2%) and duration of session was >4.5 h in 135 (15%; maximum duration 6 h). In addition, we could investigate the citrate, calcium and acid–basis status during haemodialysis sessions performed with (citrate group, n = 20 sessions) or without (citrate-free group, n = 19 sessions) citrate in the dialysate. In 20 sessions performed in patients with underlying liver disorders and using calcium-free citrate-containing dialysate, patients’ ionized calcium (iCa) and serum citrate levels were stable and remained within the normal range, respectively. Post-filter iCa was below 0.4 mmol/L in 19/20 sessions and citrate was 0.304 mmol/L (range: 0.011; 0.548). In 19 sessions that used calcium and citrate-free dialysate, post-filter iCa was 0.41 mmol/L (0.34; 0.5) and all sessions extended to 4 h or beyond.

Conclusions

Regional anticoagulation of haemodialysis with a calcium-free dialysate and calcium reinjection according to the ionic dialysance is safe. Adding citrate to the dialysate is not mandatory to prevent dialysis circuit clotting in most patients.
A picture is worth a thousand words: exploring the roles of caregivers and the home environment of ventricular assist device patients
Authors: Abshire Martha A. , Bidwell Julie T. , Pavlovic Noelle , DeGroot Lyndsay , Mammos Dimitra , Larsen Luke , Bautista Svetlana , Davidson Patricia M.
Published: April 2021

Aims

Caregivers of persons living with ventricular assist devices (VADs) are integrally involved in both medical and non-medical care. We sought to understand tasks caregivers perform after surgical recovery, ways the home is adapted for those tasks, and presence of home safety hazards.

Methods and results

We conducted semi-structured interviews with persons living with a VAD and their caregivers. Pictures were taken of areas in the home where: (i) caregiving activities occurred, (ii) VAD or medical supplies were kept, and (iii) home adaptations were made for VAD care. Pictures were described in written detail and analysed. A qualitative descriptive approach was used for analysis. The sample consisted of 10 dyads, with mostly spousal relationships (60%) between male patients (60%) and female caregivers (80%). Three themes were identified: (i) Evolution of Caregiving and Support: Patients gain independence, but caregivers are still needed, (ii) Adapting the Home Environment: Changes are focused on functional needs, and (iii) Hidden Dangers: Illumination of safety concerns by photographs. Assistance with bathing, driveline care, and medication management were common caregiving tasks. Most home adaptations occurred in the bathroom and bedroom including sleeping recliners, shower chairs, removable shower heads, and hanging hooks to hold VAD equipment. Safety hazards included minimal space for safe ambulation, infection risk, and home-made adaptations to the environment.

Conclusions

These findings describe key home caregiving tasks, home adaptations, and safety concerns that require further education and support. Utilizing pictures may be a feasible method for assessing VAD teaching, caregiving needs, and identifying potential risks.
Functional Characterization of the Adenylyl Cyclase Gene sgs-1 by Analysis of a Mutational Spectrum in Caenorhabditis elegans
Authors: Moorman Celine , Plasterk Ronald H A
Published: April 2021

The sgs-1 (suppressor of activated Gαs) gene encodes one of the four adenylyl cyclases in the nematode C. elegans and is most similar to mammalian adenylyl cyclase type IX. We isolated a complete loss-of-function mutation in sgs-1 and found it to result in animals with retarded development that arrest in variable larval stages. sgs-1 mutant animals exhibit lethargic movement and pharyngeal pumping and (while not reaching adulthood) have a mean life span that is >50% extended compared to wild type. An extensive set of reduction-of-function mutations in sgs-1 was isolated in a screen for suppressors of a neuronal degeneration phenotype induced by the expression of a constitutively active version of the heterotrimeric Gαs subunit of C. elegans. Although most of these mutations change conserved residues within the catalytic domains of sgs-1, mutations in the less-conserved transmembrane domains are also found. The sgs-1 reduction-of-function mutants are viable and have reduced locomotion rates, but do not show defects in pharyngeal pumping or life span.
Alterations of the Portal Protein, gpB, of Bacteriophage λ Suppress Mutations in cosQ, the Site Required for Termination of DNA Packaging
Authors: Wieczorek Douglas J , Didion Lisa , Feiss Michael
Published: April 2021

The cosQ site of bacteriophage λ is required for DNA packaging termination. Previous studies have shown that cosQ mutations can be suppressed in three ways: by a local suppressor within cosQ, an increase in the length of the λ chromosome, and missense mutations affecting the prohead’s portal protein, gpB. In the present work, revertants of a set of lethal cosQ mutants were screened for suppressors. Seven new cosQ suppressors affected gene B, which encodes the portal protein of the prohead. All seven were allelenonspecific suppressors of cosQ mutations. Experiments with several phages having two cosQ suppressors showed that the suppression effects were additive. Furthermore, these double suppressors had minimal effects on the growth of cosQ+ phages. These trans-acting suppressors affecting the portal protein are proposed to allow the mutant cosQ site to be more efficiently recognized, due to the slowing of the rate of translocation.
Naturally Occurring Indel Variation in the Brassica nigra COL1 Gene Is Associated With Variation in Flowering Time
Authors: Österberg Marita Kruskopf , Shavorskaya Oksana , Lascoux Martin , Lagercrantz Ulf
Published: April 2021

Previous QTL mapping identified a Brassica nigra homolog to Arabidopsis thaliana CO as a candidate gene affecting flowering time in B. nigra. Transformation of an A. thaliana co mutant with two different alleles of the B. nigra CO (Bni COa) homolog, one from an early-flowering B. nigra plant and one from a late one, did not show any differential effect of the two alleles on flowering time. The DNA sequence of the coding region of the two alleles was also identical, showing that nucleotide variation influencing flowering time must reside outside the coding region of Bni COa. In contrast, the nucleotide sequence of the B. nigra COL1 (Bni COL1) gene located 3.5 kb upstream of Bni COa was highly diverged between the alleles from early and late plants. One indel polymorphism in the Bni COL1 coding region, present in several natural populations of B. nigra, displayed a significant association with flowering time within a majority of these populations. These data indicate that a quantitative trait nucleotide (QTN) affecting flowering time is located within or close to the Bni COL1 gene. The intergenic sequence between Bni COL1 and Bni COa displayed a prominent peak of divergence 1 kb downstream of the Bni COL1 coding region. This region could contain regulatory elements for the downstream Bni COa gene. Our data suggest that a naturally occurring QTN for flowering time affects the function or expression of either Bni COL1 or Bni COa.
Comparative Analysis of Quantitative Trait Loci Controlling Glucosinolates, Myrosinase and Insect Resistance in Arabidopsis thaliana
Authors: Kliebenstein Daniel , Pedersen Deana , Barker Bridget , Mitchell-Olds Thomas
Published: April 2021

Evolutionary interactions among insect herbivores and plant chemical defenses have generated systems where plant compounds have opposing fitness consequences for host plants, depending on attack by various insect herbivores. This interplay complicates understanding of fitness costs and benefits of plant chemical defenses. We are studying the role of the glucosinolate-myrosinase chemical defense system in protecting Arabidopsis thaliana from specialist and generalist insect herbivory. We used two Arabidopsis recombinant inbred populations in which we had previously mapped QTL controlling variation in the glucosinolate-myrosinase system. In this study we mapped QTL controlling resistance to specialist (Plutella xylostella) and generalist (Trichoplusia ni) herbivores. We identified a number of QTL that are specific to one herbivore or the other, as well as a single QTL that controls resistance to both insects. Comparison of QTL for herbivory, glucosinolates, and myrosinase showed that T. ni herbivory is strongly deterred by higher glucosinolate levels, faster breakdown rates, and specific chemical structures. In contrast, P. xylostella herbivory is uncorrelated with variation in the glucosinolate-myrosinase system. This agrees with evolutionary theory stating that specialist insects may overcome host plant chemical defenses, whereas generalists will be sensitive to these same defenses.
Two-Generation Analysis of Pollen Flow Across a Landscape. IV. Estimating the Dispersal Parameter
Authors: Austerlitz Frédéric , Smouse Peter E
Published: April 2021

The distance of pollen movement is an important determinant of the neighborhood area of plant populations. In earlier studies, we designed a method for estimating the distance of pollen dispersal, on the basis of the analysis of the differentiation among the pollen clouds of a sample of females, spaced across the landscape. The method was based solely on an estimate of the global level of differentiation among the pollen clouds of the total array of sampled females. Here, we develop novel estimators, on the basis of the divergence of pollen clouds for all pairs of females, assuming that an independent estimate of adult population density is available. A simulation study shows that the estimators are all slightly biased, but that most have enough precision to be useful, at least with adequate sample sizes. We show that one of the novel pairwise methods provides estimates that are slightly better than the best global estimate, especially when the markers used have low exclusion probability. The new method can also be generalized to the case where there is no prior information on the density of reproductive adults. In that case, we can jointly estimate the density itself and the pollen dispersal distance, given sufficient sample sizes. The bias of this last estimator is larger and the precision is lower than for those estimates based on independent estimates of density, but the estimate is of some interest, because a meaningful independent estimate of the density of reproducing individuals is difficult to obtain in most cases.
Enhancement of Saccharomyces cerevisiae End-Joining Efficiency by Cell Growth Stage but Not by Impairment of Recombination
Authors: Karathanasis Elissa , Wilson Thomas E
Published: April 2021

Cells can repair DNA double-strand breaks by both homologous and nonhomologous mechanisms. To explore the basis of pathway utilization, we developed both plasmid and chromosomal yeast repair assays in which breaks are created with restriction endonucleases so that nonhomologous end-joining (NHEJ) competes with the single-strand annealing (SSA) recombination pathway, which we show acts with high efficiency via terminal direct repeats of only 28 bp and with reduced but measurable efficiency at 10 bp. The chromosomal assay utilizes a novel approach termed suicide deletion in which the endonuclease cleaves its own gene from the chromosome, thereby ending the futile cleavage cycle that otherwise prevents detection of simple-religation events. Eliminating SSA as a possibility in either assay, either by removal of the direct repeat or by mutation of RAD52, increased the relative but not the absolute efficiency of NHEJ. In contrast, the apparent efficiency of NHEJ was specifically increased in the G1 stage of the haploid cell cycle, as well as by the glucose depletion-signaled transition to stationary phase. The combined results argue against a model in which pathway utilization is determined by a passive competition. Instead, they demonstrate an active regulation designed to optimize the likelihood of genome restoration based on cell state.
Formation of Large Palindromic DNA by Homologous Recombination of Short Inverted Repeat Sequences in Saccharomyces cerevisiae
Authors: Butler David K , Gillespie David , Steele Brandi
Published: April 2021

Large DNA palindromes form sporadically in many eukaryotic and prokaryotic genomes and are often associated with amplified genes. The presence of a short inverted repeat sequence near a DNA double-strand break has been implicated in the formation of large palindromes in a variety of organisms. Previously we have established that in Saccharomyces cerevisae a linear DNA palindrome is efficiently formed from a single-copy circular plasmid when a DNA double-strand break is introduced next to a short inverted repeat sequence. In this study we address whether the linear palindromes form by an intermolecular reaction (that is, a reaction between two identical fragments in a head-to-head arrangement) or by an unusual intramolecular reaction, as it apparently does in other examples of palindrome formation. Our evidence supports a model in which palindromes are primarily formed by an intermolecular reaction involving homologous recombination of short inverted repeat sequences. We have also extended our investigation into the requirement for DNA double-strand break repair genes in palindrome formation. We have found that a deletion of the RAD52 gene significantly reduces palindrome formation by intermolecular recombination and that deletions of two other genes in the RAD52-epistasis group (RAD51 and MRE11) have little or no effect on palindrome formation. In addition, palindrome formation is dramatically reduced by a deletion of the nucleotide excision repair gene RAD1.
General Statistics of Stochastic Process of Gene Expression in Eukaryotic Cells
Authors: Kuznetsov V A , Knott G D , Bonner R F
Published: April 2021

Thousands of genes are expressed at such very low levels (≤1 copy per cell) that global gene expression analysis of rarer transcripts remains problematic. Ambiguity in identification of rarer transcripts creates considerable uncertainty in fundamental questions such as the total number of genes expressed in an organism and the biological significance of rarer transcripts. Knowing the distribution of the true number of genes expressed at each level and the corresponding gene expression level probability function (GELPF) could help resolve these uncertainties. We found that all observed large-scale gene expression data sets in yeast, mouse, and human cells follow a Pareto-like distribution model skewed by many low-abundance transcripts. A novel stochastic model of the gene expression process predicts the universality of the GELPF both across different cell types within a multicellular organism and across different organisms. This model allows us to predict the frequency distribution of all gene expression levels within a single cell and to estimate the number of expressed genes in a single cell and in a population of cells. A random “basal” transcription mechanism for protein-coding genes in all or almost all eukaryotic cell types is predicted. This fundamental mechanism might enhance the expression of rarely expressed genes and, thus, provide a basic level of phenotypic diversity, adaptability, and random monoallelic expression in cell populations.
Maximal Power Tests for Detecting Defects in Meiotic Recombination
Authors: Milac Thomas I , Adler Frederick R , Smith Gerald R
Published: April 2021

We have determined the marker separations (genetic distances) that maximize the probability, or power, of detecting meiotic recombination deficiency when only a limited number of meiotic progeny can be assayed. We find that the optimal marker separation is as large as 30–100 cM in many cases. Provided the appropriate marker separation is used, small reductions in recombination potential (as little as 50%) can be detected by assaying a single interval in as few as 100 progeny. If recombination is uniformly altered across the genomic region of interest, the same sensitivity can be obtained by assaying multiple independent intervals in correspondingly fewer progeny. A reduction or abolition of crossover interference, with or without a reduction of recombination proficiency, can be detected with similar sensitivity. We present a set of graphs that display the optimal marker separation and the number of meiotic progeny that must be assayed to detect a given recombination deficiency in the presence of various levels of crossover interference. These results will aid the optimal design of experiments to detect meiotic recombination deficiency in any organism.