While the idea that adding pyrogenic carbon (referred to as ‘biochar’ when used as a soil amendment) will enhance soil fertility and carbon sequestration has gained widespread attention, ...understanding of its chemical and physical characteristics and the methods most appropriate to determine them have lagged behind. This type of information is needed to optimize the properties of biochar for specific purposes such as nutrient retention, pH amelioration or contaminant remediation. A number of surface properties of a range of biochar types were examined to better understand how these properties were related to biochar production conditions, as well as to each other. Among biochars made from oak (
Quercus lobata), pine (
Pinus taeda) and grass (
Tripsacum floridanum) at 250
°C in air and 400 and 650
°C under N
2, micropore surface area (measured by CO
2 sorptometry) increased with production temperature as volatile matter (VM) decreased, indicating that VM was released from pore-infillings. The CEC, determined using K
+ exchange, was about 10
cmol
c
kg
−1 for 400 and 650
°C chars and did not show any pH dependency, whereas 250
°C biochar CECs were pH-dependant and rose to as much as 70
cmol
c
kg
−1 at pH 7. Measurements of surface charge on biochar particles indicated a zeta potential of −
9 to −
4
mV at neutral pH and an iso-electric point of pH 2–3. However, a colloidal or dissolved biochar component was 4–5 times more electronegative. Total acid functional group concentration ranged 4.4–8.1
mmol
g
−1 (measured by Boehm titration), decreased with production temperature, and was directly related to VM content. Together, these findings suggest that the VM component of biochar carries its acidity, negative charge, and thus, complexation ability. However, not all acid functional groups exchanged cations as the number of cation exchanging sites (CEC) was about 10 times less than the number of acid functional groups present on biochar surfaces and varied with biomass type. These findings suggest that lower temperature biochars will be better used to increase soil CEC while high temperature biochars will raise soil pH. Although no anion exchange capacity was measured in the biochars, they may sorb phosphate and nitrate by divalent cation bridging.
► Biochar surface area mainly in micropores and best measured by CO
2 sorptometry. ► The volatile component of biochar generates biochar acidity and CEC. ► Biochar surface is negatively charged. ► High temperature chars increase soil pH and low temperature chars increase CEC.
Summary Background Fetal alcohol spectrum disorder (FASD) is related to many comorbidities because of the permanent effects of prenatal alcohol exposure on the fetus. We aimed to identify the ...comorbid conditions that co-occur in individuals with FASD and estimate the pooled prevalence of comorbid conditions occurring in individuals with fetal alcohol syndrome (FAS). Methods We did a systematic literature search of studies reporting on the comorbidity and cause of death in individuals with FASD using multiple electronic bibliographic databases, searching for studies published up to July, 2012. We included original research published in a peer-reviewed journal in the English language. We used the following criteria for determining study quality: use of an established FASD diagnostic guideline, study setting, method of data collection, and sample size. All comorbid disease conditions were coded according to the International Classification of Diseases, tenth revision (ICD-10). To estimate the pooled prevalence of comorbid conditions found to co-occur in individuals with FAS, we did meta-analyses assuming a random-effects model. Findings Of 5068 studies found, 127 met eligibility criteria for data extraction. From those studies, we identified 428 comorbid conditions co-occurring in individuals with FASD, spanning across 18 of 22 chapters of the ICD-10. The most prevalent disease conditions were within the sections of congenital malformations, deformities, and chromosomal abnormalities, and mental and behavioural disorders. 33 studies reported data for frequency in a total of 1728 participants with FAS. The five comorbid conditions with the highest pooled prevalence (between 50% and 91%) included abnormal results of function studies of peripheral nervous system and special senses, conduct disorder, receptive language disorder, chronic serous otitis media, and expressive language disorder. Interpretation The high prevalence of comorbid conditions in individuals with FASD highlights the importance of assessing prenatal alcohol exposure as a substantial clinical risk factor for comorbidity. The harmful effects of alcohol on a developing fetus represent many cases of preventable disability, and thus, alcohol use during pregnancy should be recognised as a public health problem globally. Funding Public Health Agency of Canada.
Potential health and environmental effects of nanoparticles need to be thoroughly assessed before their widespread commercialization. Though there are few studies on cytotoxicity of nanoparticles on ...mammalian and human cell lines, there are hardly any reports on genotoxic and cytotoxic behavior of nanoparticles in plant cells. This study aims to investigate cytotoxic and genotoxic impacts of silver nanoparticles using root tip cells of
Allium cepa as an indicator organism.
A.
cepa root tip cells were treated with four different concentrations (25, 20, 75, and 100
ppm) of engineered silver nanoparticles (below 100
nm size) dispersion, to study endpoints like mitotic index, distribution of cells in mitotic phases, different types of chromosomal aberrations, disturbed metaphase, sticky chromosome, cell wall disintegration, and breaks. For each concentration five sets of microscopic observations were carried out. No chromosomal aberration was observed in the control (untreated onion root tips) and the mitotic index (MI) value was 60.3%. With increasing concentration of the nanoparticles decrease in the mitotic index was noticed (60.30% to 27.62%). The different cytological effects including the chromosomal aberrations were studied in detail for the treated cells as well as control. We infer from this study that silver nanoparticles could penetrate plant system and may impair stages of cell division causing chromatin bridge, stickiness, disturbed metaphase, multiple chromosomal breaks and cell disintegration. The findings also suggest that plants as an important component of the ecosystems need to be included when evaluating the overall toxicological impact of the nanoparticles in the environment.
When it comes to “bioplastics”, we currently notice an immense complexity of this topic, and, most of all, a plethora of contradictory legislations, which confuses or even misleads insufficiently ...informed consumers. The present article therefore showcases microbial polyhydroxyalkanoate (PHA) biopolyesters as the prime class of “bioplastics” sensu stricto. In particular, biodegradability of PHA as its central benefit in elevating the current plastic waste scenario is elaborated on the biochemical basis: this covers aspects of the enzymatic machinery involved both in intra- and extracellular PHA degradation, and environmental factors impacting biodegradability. Importantly, PHA degradability is contextualized with potential fields of application of these materials. It is further shown how the particularities of PHA in terms of feedstocks, mode of synthesis, degradability, and compostability differ from other polymeric materials sold as “bioplastics”, highlighting the unique selling points of PHA as “green” plastic products in the circular economy. Moreover, current standards, norms, and certificates applicable to PHA are presented as basis for a straight-forward, scientifically grounded classification of “bioplastics”.
biochar dilemma Mukherjee, A; Lal, R
Soil research (Collingwood, Vic.),
01/2014, Letnik:
52, Številka:
3
Journal Article
Recenzirano
Any strategy towards widespread adoption of biochar as a soil amendment is constrained by the scarcity of field-scale data on crop response, soil quality and environmental footprint. Impacts of ...biochar as a soil amendment over a short period based on laboratory and greenhouse studies are often inconclusive and contradictory. Yet biochar is widely advocated as a promising tool to improve soil quality, enhance C sequestration, and increase agronomic yield. While substantial reviews exist on positive aspects of biochar research, almost no review to date has compiled negative aspects of it. Although biochar science is advancing, available data indicate several areas of uncertainty. This article reviews a range of negative impacts of biochar on soil quality, crop yield, and associated financial risk. This review is important because advances in biochar research demand identification of the risks (if any) of using biochar as a soil amendment before any large-scale field application is recommended. It is the first attempt to acknowledge such issues with biochar application in soil. Thus, the aims of this review are to assess the uncertainties of using biochar as a soil amendment, and to clarify ambiguity regarding interpretation of research results. Along with several unfavourable changes in soil chemical, physical and biological properties, reduction in crop yield has been reported. Relative to controls, the yield for biochar-amended soil (application rate 0.2–20% w/w) has been reduced by 27, 11, 36, 74, and 2% for rice (Oryza sativa L.) (control 3.0Mgha-1), wheat (Triticum spp. L.) (control 4.6Mgha-1), maize (Zea mays L.) (control 4.7Mgha-1), lettuce (Lactuca sativa L.) (control 5.4Mgha-1), and tomato (Solanum lycopersicum L.) (control 265Mgha-1), respectively. Additionally, compared with unamended soils, gaseous emissions from biochar-amended soils (application rate 0.005–10% w/w) have been enhanced up to 61, 152 and 14% for CO2 (control 9.7Mgha-1 year-1), CH4 (control 222kg ha-1 year-1), and N2O (control 4.3kg ha-1 year-1), respectively. Although biochar has the potential to mitigate several environmental problems, the data collated herein indicate that a systematic road-map for manufacturing classification of biochars, and cost–benefit analysis, must be developed before implementation of field-scale application.
The nucleons (protons and neutrons) are by far the most abundant form of matter in our visible Universe; they are composite particles made of quarks and gluons, the fundamental quanta of Quantum ...Chromo Dynamics (QCD). The usual interpretation of the nucleon dynamics in high energy interactions is often limited to a simple one-dimensional picture of a fast moving nucleon as a collection of co-linearly moving quarks and gluons (partons), interacting accordingly to perturbative QCD rules. However, massive experimental evidence shows that, in particular when transverse spin dependent observables are involved, such a simple picture is not adequate. The intrinsic transverse motion of partons has to be taken into account; this opens the way to a new, truly 3-dimensional (3D) study of the nucleon structure. A review of the main experimental data, their interpretation and understanding in terms of new transverse momentum dependent partonic distributions, and the progress in building a 3D imaging of the nucleon is presented.
Aptamers are a special class of nucleic acid molecules that are beginning to be investigated for clinical use. These small RNA/DNA molecules can form secondary and tertiary structures capable of ...specifically binding proteins or other cellular targets; they are essentially a chemical equivalent of antibodies. Aptamers have the advantage of being highly specific, relatively small in size, and non-immunogenic. Since the discovery of aptamers in the early 1990s, great efforts have been made to make them clinically relevant for diseases like cancer, HIV, and macular degeneration. In the last two decades, many aptamers have been clinically developed as inhibitors for targets such as vascular endothelial growth factor (VEGF) and thrombin. The first aptamer based therapeutic was FDA approved in 2004 for the treatment of age-related macular degeneration and several other aptamers are currently being evaluated in clinical trials. With advances in targeted-therapy, imaging, and nanotechnology, aptamers are readily considered as potential targeting ligands because of their chemical synthesis and ease of modification for conjugation. Preclinical studies using aptamer-siRNA chimeras and aptamer targeted nanoparticle therapeutics have been very successful in mouse models of cancer and HIV. In summary aptamers are in several stages of development, from pre-clinical studies to clinical trials and even as FDA approved therapeutics. In this review, we will discuss the current state of aptamers in clinical trials as well as some promising aptamers in pre-clinical development.
In this article, role of ocean advection and atmospheric heat fluxes on recent decadal (2000–2019) decrease of sea-ice in the Arctic (60
∘
N–90
∘
N) has been investigated using an ocean sea-ice ...coupled model, known as Modular Ocean Model of version 5 with Sea Ice Simulator (MOMSIS). MOMSIS successfully simulates AVHRR observed decadal change of sea-ice concentration (SIC) and sea surface temperature (SST) in the Arctic during all four seasons; winter (December–February), spring (March–May), summer (June–August) and autumn (September–November) except few occasions. Also, best performance of the MOMSIS are restricted at south of 80
∘
N with statistical significance of more than 90
%
. We have also divided Arctic Ocean into eight sectors for our detailed analysis. Maximum decadal decrease of SIC and increase of SST has been observed in the Barents (sector 2), Kara (sector 3) and Laptev (sector 4) Sea regions of the Arctic using both AVHRR and MOMSIS with statistical significance of 90
%
. Also, very small decadal decrease (increase) of SIC (SST) has been observed in the Norwegian (sector 1) and Beaufort (sector 7) Sea regions of the Arctic using both AVHRR and MOMSIS. Mixed layer heat budget has been performed to understand role of thermodynamics processes on decadal change of SIC and SST in the Arctic. Strong decadal change of net atmospheric heat (NAH) fluxes are responsible for high decadal change of SIC and SST in the Barents (sector 2), Kara (sector 3) and Laptev (sector 4) Sea regions of the Arctic. In the Norwegian (sector 1) and Beaufort (sector 7) Sea, strong destructive interference between decadal change of NAH fluxes and ocean advection play an important role for small decadal change of SIC and SST during all four seasons. Also, for ocean advection, horizontal part dominate compared to vertical in all eight sector of the Arctic.
Achieving circularity in materials requires fundamental changes in the polymers we use today and the way they are produced. Functional polymeric materials from renewable feedstocks that do not ...conflict with food and animal feed, and their renewal through biodegradation under diverse environmental conditions as the desired end-of-life option indeed constitute a paradigm shift for today's plastics industry. Considering the ever-increasing environmental problems associated with the disposal or incineration of fossil plastics, the increasing microplastic formation, food contamination, and rising atmospheric CO.sub.2 concentrations, have made it clear that the time is ripe for alternative, innovative, and sustainable polymers with plastic-like properties. In this nexus, the present review shines new light on the benefits of biobased and, at the same time, biodegradable microbial polyhydroxyalkanoate (PHA) biopolyesters. Special emphasis is dedicated to carbon recyclability through biodegradability and compostability of these fascinating natural materials, which are slowly but surely being commercialized as replacement for fossil plastics that are produced and disposed of in multi-million-ton scale annually, resulting in a growing environmental threat. This review highlights that end-of-life options of PHA are analogous or even superior to another well-known polymer from nature, cellulose, while PHA offer the additional attributes of plastics in use with tailor-made properties. Finally, the review demonstrates how PHA biopolyesters can contribute to reaching many of the heavily discussed and desired UN Sustainable Development Goals. Keywords: biopolymers, biodegradable polymers, circular bioeconomy, circular materials, microbial biopolyesters, microplastics, polyhydroxyalkanoate, UN Sustainable Development goals
Short and long-term impacts of biochar on soil properties under field conditions are poorly understood. In addition, there is a lack of field reports of the impacts of biochar on soil physical ...properties, gaseous emissions and C stability, particularly in comparison with other amendments. Thus, three amendments – biochar produced from oak at 650°C, humic acid (HA) and water treatment residual – (WTR) were added to a scalped silty-loam soil @ 0.5% (w/w) in triplicated plots under soybean. Over the 4-month active growing season, all amendments significantly increased soil pH, but the effect of biochar was the greatest. Biochar significantly increased soil-C by 7%, increased sub-nanopore surface area by 15% and reduced soil bulk density by 13% compared to control. However, only WTR amendment significantly increased soil nanopore surface area by 23% relative to the control. While total cumulative CH4 and CO2 emissions were not significantly affected by any amendment, cumulative N2O emission was significantly decreased in the biochar-amended soil (by 92%) compared to control over the growing period. Considering both the total gas emissions and the C removed from the atmosphere as crop growth and C added to the soil, WTR and HA resulted in net soil C losses and biochar as a soil C gain. However, all amendments reduced the global warming potential (GWP) of the soil and biochar addition even produced a net negative GWP effect. The short observation period, low application rate and high intra-treatment variation resulted in fewer significant effects of the amendments on the physicochemical properties of the soils than one might expect indicating further possible experimentation altering these variables. However, there was clear evidence of amendment–soil interaction processes affecting both soil properties and gaseous emissions, particularly for biochar, that might lead to greater changes with additional field emplacement time.
•Short-term field study conducted comparing soil quality under HA, WTR, and biochar.•Biochar significantly increased soil-C and N2-surface area and reduced bulk density.•Only WTR significantly increased soil microporous surface area compared to control.•Cumulative N2O emission was significantly decreased in the biochar-amended soil.•WTR and HA resulted in net soil C losses and biochar as a soil C gain.
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