scholarly journals Natural and anthropogenic impacts reflected by paleoclimate proxy parameters in a lake-forest system in Bukovina, Romania

2021 ◽  
Vol 70 (4) ◽  
pp. 339-351
Author(s):  
Máté Karlik ◽  
◽  
Anna Vancsik ◽  
Zoltán Szalai ◽  
Marcel Mîndrescu ◽  
...  
Keyword(s):  
Organic Geochemistry ◽  
Anthropogenic Impacts ◽  
Sediment Cores ◽  
Research Area ◽  
High Temporal Resolution ◽  
Natural Processes ◽  
Weathering Indices ◽  
Eastern Carpathians ◽  
Wide Range ◽  
Paleoclimate Proxy

The research area is located in the Eastern Carpathians, Romania. This region is rich in various formations and indicates significant potential for paleo-environmental reconstruction. The present research was carried out on sediment cores collected at lake Bolătău-Feredeu, Feredeului Mountains (Eastern Carpathians, Romania). Preliminary examination of the sediment confirmed the possibility for data analysis with high temporal resolution. The aim of the research was to clarify and supplement the findings of previous research at this site, to explore the relationships between proxy parameters and to elucidate the cause for the changes. Core dating was carried out using 210Pb and radiocarbon isotopes and indicated that sediment cores span the past 500 years. The research uses a wide range of methodologies, including organic geochemistry with calculated n alkane indices (Phw and Pwax). Based on these proxies, the changes of woody and herbaceous coverage in the catchment can be estimated. Moreover, element concentration, weathering indices and particle size distribution assist to detect climate changes in the catchment area. The data and conclusions yielded by the analysis were compared with the regional modelled temperature profile, based on which five periods were separated. In addition to natural and anthropogenic events, the main factor among the natural processes is the change in annual temperature. Based on the obtained data, several parameters were found to be suitable for monitoring past temperature changes.

Pharmaceutical Co-Crystals - Design, Development and Applications

2020 ◽  
Vol 10 (3) ◽  
pp. 169-184
Author(s):  
Rachna Anand ◽  
Arun Kumar ◽  
Arun Nanda
Keyword(s):  
Physicochemical Properties ◽  
Crystal Engineering ◽  
Pharmacological Action ◽  
Physicochemical Characteristics ◽  
Research Area ◽  
Dissolution Profile ◽  
Design Development ◽  
Drug Molecule ◽  
Wide Range ◽  
Major Factors

Background: Solubility and dissolution profile are the major factors which directly affect the biological activity of a drug and these factors are governed by the physicochemical properties of the drug. Crystal engineering is a newer and promising approach to improve physicochemical characteristics of a drug without any change in its pharmacological action through a selection of a wide range of easily available crystal formers. Objective: The goal of this review is to summarize the importance of crystal engineering in improving the physicochemical properties of a drug, methods of design, development, and applications of cocrystals along with future trends in research of pharmaceutical co-crystals. Co-crystallization can also be carried out for the molecules which lack ionizable functional groups, unlike salts which require ionizable groups. Conclusion: Co-crystals is an interesting and promising research area amongst pharmaceutical scientists to fine-tune the physicochemical properties of drug materials. Co-crystallization can be a tool to increase the lifecycle of an older drug molecule. Crystal engineering carries the potential of being an advantageous technique than any other approach used in the pharmaceutical industry. Crystal engineering offers a plethora of biopharmaceutical and physicochemical enhancements to a drug molecule without the need of any pharmacological change in the drug.

scholarly journals Anti-Biofilm Molecules Targeting Functional Amyloids

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 795
Author(s):  
Leticia Matilla-Cuenca ◽  
Alejandro Toledo-Arana ◽  
Jaione Valle
Keyword(s):  
Biofilm Formation ◽  
Therapeutic Strategy ◽  
Research Area ◽  
Therapeutic Strategies ◽  
Structural Components ◽  
Significant Issue ◽  
Wide Range ◽  
Effective Therapeutic Strategy ◽  
Functional Amyloids ◽  
Biofilm Matrix

The choice of an effective therapeutic strategy in the treatment of biofilm-related infections is a significant issue. Amyloids, which have been historically related to human diseases, are now considered to be prevailing structural components of the biofilm matrix in a wide range of bacteria. This assumption creates the potential for an exciting research area, in which functional amyloids are considered to be attractive targets for drug development to dissemble biofilm structures. The present review describes the best-characterized bacterial functional amyloids and focuses on anti-biofilm agents that target intrinsic and facultative amyloids. This study provides a better understanding of the different modes of actions of the anti-amyloid molecules to inhibit biofilm formation. This information can be further exploited to improve the therapeutic strategies to combat biofilm-related infections.

scholarly journals An Overview on the Rheology, Mechanical Properties, Durability, 3D Printing, and Microstructural Performance of Nanomaterials in Cementitious Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2950
Author(s):  
Hongwei Song ◽  
Xinle Li
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Research Area ◽  
Cementitious Composites ◽  
Split Tensile Strength ◽  
Contour Crafting ◽  
Wide Range ◽  
Active Research

The most active research area is nanotechnology in cementitious composites, which has a wide range of applications and has achieved popularity over the last three decades. Nanoparticles (NPs) have emerged as possible materials to be used in the field of civil engineering. Previous research has concentrated on evaluating the effect of different NPs in cementitious materials to alter material characteristics. In order to provide a broad understanding of how nanomaterials (NMs) can be used, this paper critically evaluates previous research on the influence of rheology, mechanical properties, durability, 3D printing, and microstructural performance on cementitious materials. The flow properties of fresh cementitious composites can be measured using rheology and slump. Mechanical properties such as compressive, flexural, and split tensile strength reveal hardened properties. The necessary tests for determining a NM’s durability in concrete are shrinkage, pore structure and porosity, and permeability. The advent of modern 3D printing technologies is suitable for structural printing, such as contour crafting and binder jetting. Three-dimensional (3D) printing has opened up new avenues for the building and construction industry to become more digital. Regardless of the material science, a range of problems must be tackled, including developing smart cementitious composites suitable for 3D structural printing. According to the scanning electron microscopy results, the addition of NMs to cementitious materials results in a denser and improved microstructure with more hydration products. This paper provides valuable information and details about the rheology, mechanical properties, durability, 3D printing, and microstructural performance of cementitious materials with NMs and encourages further research.

scholarly journals Abandoned agricultural soils from the central part of the Yamal region of Russia: morphology, diversity, and chemical properties

2020 ◽  
Vol 5 (1) ◽  
pp. 94-106
Author(s):  
Evgeny Abakumov ◽  
Evgeniya Morgun ◽  
Alexandr Pechkin ◽  
Vyacheslav Polyakov
Keyword(s):  
Land Use ◽  
Agricultural Soils ◽  
Anthropogenic Impacts ◽  
Chemical Properties ◽  
Organic Carbon Content ◽  
Active Growth ◽  
Natural Processes ◽  
Agrochemical Properties ◽  
Fallow Lands ◽  
Abandoned Lands

AbstractThe post-anthropogenic and soil cover transformations of former agricultural soils on the abandoned lands in the Russian Arctic territory are poorly investigated due to the active growth of the city complexes and increasing area occupied by agricultural lands. That is lead to an increase in the area of the arable lands surrounding the polar urbanized territories. Today, most of that land allocated for agricultural needs has been abandoned or affected by other types of land use. This study aimed to investigate the abandoned lands surrounding some of the settlements in the central part of the Yamal region. The soil diversity, morphology, and chemical and agrochemical properties were investigated with special reference to the specific transformations that occur to fallow lands under permafrost-affected cryogenic-ecosystem conditions. Analysis of data show that these soils are characterized by features relating to both, previous (and existing), anthropogenic impacts and natural processes such as cryogenic mass transfer. The degradation of the arable humus-enriched horizon was not as pronounced as it has been in more humid boreal environments over recent decades. The organic carbon content in topsoil depends on the land use and varied considerably among the soil types. The former arable topsoil horizon has been stable over time in terms of its morphological features and agrochemical state. Despite the high soil acidity levels, thenutrient content in the anthropogenically impacted soils was still high, even though being abandoned for 20 years.

Millennial scale variability of denudation rates for the last 15 kyr inferred from the detrital 10Be record of Lake Stappitz in the Hohe Tauern massif, Austrian Alps

The Holocene ◽  
2017 ◽  
Vol 27 (12) ◽  
pp. 1914-1927 ◽  
Author(s):  
Reto Grischott ◽  
Florian Kober ◽  
Maarten Lupker ◽  
Juergen M Reitner ◽  
Ruth Drescher-Schneider ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Anthropogenic Impacts ◽  
Sediment Cores ◽  
Tight Coupling ◽  
Climatic Forcing ◽  
Erosion Rates ◽  
Austrian Alps ◽  
Denudation Rates ◽  
Time Period ◽  
Flooding Events

Reconstructing paleo-denudation rates over Holocene timescales in an Alpine catchment provides a unique opportunity to isolate the climatic forcing of denudation from other tectonic or anthropogenic effects. Cosmogenic 10Be on two sediment cores from Lake Stappitz (Austrian Alps) were measured yielding a 15-kyr-long catchment-averaged denudation record of the upstream Seebach Valley. The persistence of a lake at the outlet of the valley fixed the baselevel, and the high mean elevation minimizes anthropogenic impacts. The 10Be record indicates a decrease in the proportion of paraglacial sediments from 15 to 7 kyr cal. BP after which the 10Be concentrations are considered to reflect hillslope erosion and thus can be converted to denudation rates. These ones significantly fluctuated over this time period: lower hillslope erosion rates of ca. 0.4 mm/year dated between 5 and 7 kyr cal. BP correlate with a stable climate, sparse flooding events and elevated temperatures that favoured the widespread growth of stabilizing soils and vegetation. Higher hillslope erosion rates of ca. 0.8 mm/year over the last ~4 kyr correlate with a variable, cooler climate where frequent flooding events enhance denudation of less protected hillslopes. Overall, our results suggest a tight coupling of climate and hillslope erosion in alpine landscapes as it has been observed in other parts of the Alps.

scholarly journals Performance of the Precipitation Occurrence Sensor System as a Precipitation Gauge

2008 ◽  
Vol 25 (2) ◽  
pp. 196-212 ◽  
Author(s):  
B. E. Sheppard ◽  
P. I. Joe
Keyword(s):  
Interquartile Range ◽  
Sensor System ◽  
Precipitation Rate ◽  
Doppler Velocity ◽  
High Temporal Resolution ◽  
Velocity Spectrum ◽  
Ratio Distribution ◽  
Precipitation Occurrence ◽  
Solid Precipitation ◽  
Wide Range

Abstract The Precipitation Occurrence Sensor System (POSS) is a small X-band Doppler radar originally developed by the Meteorological Service of Canada for reporting the occurrence, type, and intensity of precipitation from Automated Weather Observing Stations. This study evaluates POSS as a gauge for measuring amounts of both liquid and solid precipitation. Different precipitation rate estimation algorithms are described. The effect of different solid precipitation types on the Doppler velocity spectrum is discussed. Lacking any accepted reference for high temporal resolution rates, the POSS precipitation rate measurements are integrated over time periods ranging from 6 h to one day and validated against international and Canadian reference gauges. Data from a wide range of sites across Canada and for periods of several years are used. The statistical performance of POSS is described in terms of the distribution of ratios of POSS to reference gauge amounts (catch ratios). In liquid precipitation the median of the catch ratio distribution is 82% and the interquartile range was between −12% and 19% about the median. In solid precipitation the median is 90% and the interquartile range is between −17% and 24% about the median. The underestimation in both liquid and solid precipitation is shown to be a function of precipitation rate and phase. The effects of radome wetting, raindrop splashing, wind, and the radar “brightband” effect on the estimation of precipitation rates are discussed.

scholarly journals Radar for projectile impact on granular media

2020 ◽  
Vol 12 (9) ◽  
pp. 855-861
Author(s):  
Felix Rech ◽  
Kai Huang
Keyword(s):  
Particle Tracking ◽  
Granular Media ◽  
Continuous Wave ◽  
High Temporal Resolution ◽  
Daily Lives ◽  
X Band ◽  
Wave Radar ◽  
Wide Range ◽  
The One ◽  
Engineering Industries

AbstractFrom the prevention of natural disasters such as landslide and avalanches, to the enhancement of energy efficiencies in chemical and civil engineering industries, understanding the collective dynamics of granular materials is a fundamental question that are closely related to our daily lives. Using a recently developed multi-static radar system operating at 10 GHz (X-band), we explore the possibility of tracking a projectile moving inside a granular medium, focusing on possible sources of uncertainties in the detection and reconstruction processes. On the one hand, particle tracking with continuous-wave radar provides an extremely high temporal resolution. On the other hand, there are still challenges in obtaining tracer trajectories accurately. We show that some of the challenges can be resolved through a correction of the IQ mismatch in the raw signals obtained. Consequently, the tracer trajectories can be obtained with sub-millimeter spatial resolution. Such an advance can not only shed light on radar particle tracking, but also on a wide range of scenarios where issues relevant to IQ mismatch arise.

scholarly journals Wintertime aerosol chemical composition, volatility, and spatial variability in the greater London area

2016 ◽  
Vol 16 (2) ◽  
pp. 1139-1160 ◽  
Author(s):  
L. Xu ◽  
L. R. Williams ◽  
D. E. Young ◽  
J. D. Allan ◽  
H. Coe ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Solid Fuel ◽  
Field Studies ◽  
Rural Site ◽  
Urban Site ◽  
High Temporal Resolution ◽  
Volatile Organics ◽  
Aerosol Mass ◽  
Rural And Urban ◽  
Wide Range

Abstract. The composition of PM1 (particulate matter with diameter less than 1 µm) in the greater London area was characterized during the Clean Air for London (ClearfLo) project in winter 2012. Two high-resolution time-of-flight aerosol mass spectrometers (HR-ToF-AMS) were deployed at a rural site (Detling, Kent) and an urban site (North Kensington, London). The simultaneous and high-temporal resolution measurements at the two sites provide a unique opportunity to investigate the spatial distribution of PM1. We find that the organic aerosol (OA) concentration is comparable between the rural and urban sites, but the contribution from different sources is distinctly different between the two sites. The concentration of solid fuel OA at the urban site is about twice as high as at the rural site, due to elevated domestic heating in the urban area. While the concentrations of oxygenated OA (OOA) are well-correlated between the two sites, the OOA concentration at the rural site is almost twice that of the urban site. At the rural site, more than 70 % of the carbon in OOA is estimated to be non-fossil, which suggests that OOA is likely related to aged biomass burning considering the small amount of biogenic SOA in winter. Thus, it is possible that the biomass burning OA contributes a larger fraction of ambient OA in wintertime than what previous field studies have suggested. A suite of instruments was deployed downstream of a thermal denuder (TD) to investigate the volatility of PM1 species at the rural Detling site. After heating at 250 °C in the TD, 40 % of the residual mass is OA, indicating the presence of non-volatile organics in the aerosol. Although the OA associated with refractory black carbon (rBC; measured by a soot-particle aerosol mass spectrometer) only accounts for < 10 % of the total OA (measured by a HR-ToF-AMS) at 250 °C, the two measurements are well-correlated, suggesting that the non-volatile organics have similar sources or have undergone similar chemical processing as rBC in the atmosphere. Although the atomic O : C ratio of OOA is substantially larger than that of solid fuel OA and hydrocarbon-like OA, these three factors have similar volatility, which is inferred from the change in mass concentration after heating at 120 °C. Finally, we discuss the relationship between the mass fraction remaining (MFR) of OA after heating in the TD and atomic O : C of OA and find that particles with a wide range of O : C could have similar MFR after heating. This analysis emphasizes the importance of understanding the distribution of volatility and O : C in bulk OA.

scholarly journals Novel Trifluoromethyl Pyrimidinone Compounds With Activity Against Mycobacterium tuberculosis

2021 ◽  
Vol 9 ◽  
Author(s):  
Erik Hembre ◽  
Julie V. Early ◽  
Joshua Odingo ◽  
Catherine Shelton ◽  
Olena Anoshchenko ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Major Change ◽  
Structural Features ◽  
Research Area ◽  
Biological Properties ◽  
Pyridyl Ring ◽  
Pyridyl Group ◽  
Gram Positive Bacteria ◽  
Wide Range ◽  
Cytotoxic Molecules

The identification and development of new anti-tubercular agents are a priority research area. We identified the trifluoromethyl pyrimidinone series of compounds in a whole-cell screen against Mycobacterium tuberculosis. Fifteen primary hits had minimum inhibitory concentrations (MICs) with good potency IC90 is the concentration at which M. tuberculosis growth is inhibited by 90% (IC90 &lt; 5 μM). We conducted a structure–activity relationship investigation for this series. We designed and synthesized an additional 44 molecules and tested all analogs for activity against M. tuberculosis and cytotoxicity against the HepG2 cell line. Substitution at the 5-position of the pyrimidinone with a wide range of groups, including branched and straight chain alkyl and benzyl groups, resulted in active molecules. Trifluoromethyl was the preferred group at the 6-position, but phenyl and benzyl groups were tolerated. The 2-pyridyl group was required for activity; substitution on the 5-position of the pyridyl ring was tolerated but not on the 6-position. Active molecules from the series demonstrated low selectivity, with cytotoxicity against eukaryotic cells being an issue. However, there were active and non-cytotoxic molecules; the most promising molecule had an MIC (IC90) of 4.9 μM with no cytotoxicity (IC50 &gt; 100 μM). The series was inactive against Gram-negative bacteria but showed good activity against Gram-positive bacteria and yeast. A representative molecule from this series showed rapid concentration-dependent bactericidal activity against replicating M. tuberculosis bacilli with ~4 log kill in &lt;7 days. Overall the biological properties were promising, if cytotoxicity could be reduced. There is scope for further medicinal chemistry optimization to improve the properties without major change in structural features.

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