Turbidimetric Determination of Anionic Polyacrylamide in Low Carbon Soil Extracts

Concerns over runoff water quality from agricultural lands and construction sites have led to the development of improved erosion control practices, including application of polyacrylamide (PAM). We developed a quick and reliable method for quantifying PAM in soil extracts at low carbon content by using a turbidimetric reagent, Hyamine 1622. Three high-molecular weight anionic PAMs differing in charge density (7, 20, and 50 mol%) and five water matrices, deionized (DI) water and extracts from four different soils, were used to construct PAM calibration curves by reacting PAM solutions with hyamine and measuring turbidity development from the PAM–hyamine complex. The PAM calibration curve with DI water showed a strong linear relationship (r2 = 0.99), and the sensitivity (slope) of calibration curves increased with increasing PAM charge density with a detection limit of 0.4 to 0.9 mg L−1. Identical tests with soil extracts showed the sensitivity of the hyamine method was dependent on the properties of the soil extract, primarily organic carbon concentration. Although the method was effective in mineral soils, the highest charge density PAM yielded a more reliable linear relationship (r2 \u3e 0.97) and lowest detection limit (0.3 to 1.2 mg L−1), compared with those of the lower charge density PAMs (0.7 to 23 mg L−1). Our results suggest that the hyamine test could be an efficient method for quantifying PAM in environmental soil water samples as long as the organic carbon in the sample is low, such as in subsurface soil material often exposed at construction sites

A new approach for measuring surface hydrological connectivity

The development of surface hydrological connectivity is a key determinant of flood magnitude in drylands. Thresholds in runoff response may be reached when isolated runoff‐generating areas connect with each other to form continuous links to river channels, enabling these areas to contribute to flood hydrographs. Such threshold behaviour explains observed nonlinearities and scale dependencies of dryland rainfall–runoff relationships and complicates attempts at flood prediction. However, field methods for measuring the propensity of a surface to transmit water downslope are lacking, and conventional techniques of infiltration measurement are often inappropriate for use on non‐agricultural drylands. Here, we argue for a reconceptualization of the dryland surface runoff process, suggesting that the downslope transfer of water should be considered alongside surface infiltration; that is, there is a need for the “aggregated” measurement of infiltration and overland flow hydraulics. Surface application of a set volume of water at a standardized rate generates runoff that travels downslope; the distance it travels downslope is determined by infiltration along the flow, integration of flow paths, and flow resistance. We demonstrate the potential of such a combined measurement system coupled with structure‐from‐motion photogrammetry to identify surface controls on runoff generation and transfer on dryland hillslopes, with vegetation, slope, surface stone cover, and surface roughness all having a significant effect. The measurement system has been used on slopes up to 37° compared with the flat surface typically required for infiltration methods. On average, the field workflow takes ~10–15 min, considerably quicker than rainfall simulation. A wider variety of surfaces can be sampled with relative ease, as the method is not restricted to stone and vegetation‐free land. We argue that this aggregated measurement represents surface connectivity and dryland runoff response better than standard hydrological approaches and can be applied on a much greater variety of dryland surfaces

Isolation and identification of halophilic bacteria from Urmia Lake in Iran

Halophiles are in all three domains of life: Archaea, Bacteria and Eucarya. Halophilic microorganisms in addition to forming a major part of life biodiversity can have many biotechnological applications. The objective of this research is isolation and identification of halophilic bacteria from Urmia Lake in Iran and the study of its bacterial biodiversity. After sampling of brines from Urmia Lake from 10 stations and depth of approximately 30-50 cm, in April 2011 and transfer to the laboratory in the sterile conditions, samples were enriched and cultured on defined media, and incubated. After appearance of colonies, selected strains were studied based on morphology, physiology and biochemical characteristics. For phylogenetic identification, their genomic DNA were extracted and amplified by PCR technique. Therefore their sequences were determined by genetic experiment based on 16S rRNA gene sequence and their similarity were analysed in GenBank of EzTaxon database. Finally the phylogenetic tree was constructed. Studied strains belonged to three genera: Halomonas 50% (including H. andesensis LC6(T) [12.5%], H. gomseomensis M12(T) [12.5%], H. hydrothermalis Slthf2(T) [12.5%], H. boliviensis LC1(T) [6.25%] and H. janggokensis M24(T) [6.25%]), Salinivibrio 25% (including S. costicola subsp. alcaliphilus DSM 16359(T) [18.75%] and S. sharmensis BAG(T) [6.25%]) and Idiomarina 25% (including I. loihiensis L2TR(T) [25%])

Single cell protein production from culture and marine fish wastes

The alarming rate of population growth has increased the demand for food production in third-world countries leading to a yawning gap in demand and supply. This has led to an increase in the number of hungry and chronically malnourished people. This situation has created a demand for the formulation of innovative and alternative proteinaceous food sources. Single cell protein production is a major step in this direction. SCP is the protein extracted from cultivated microbial biomass. Algae, fungi and bacteria are the chief sources of microbial protein that can be utilized as SCP. Produced proteins from these microbes have various nutrition values. SCP is the manufacture of cell mass using microorganisms by culturing on available agriculture, industrial wastes and fisheries by products. Fish wastes due to high protein are the most important substrates for SCP production. In this study, SCP production was done from Silver carp and tuna fish wastes (head, tail and vise versa) and cooked water of canned tuna factories. The used microbes were six genus and species of yeasts include Candida utilis, Saccharomyces cereviceae, Rhodotorula, Khyveromyces marxians, Zygosaccharomyces rouxii and Bacillus subtilis and B.licheniformis. The examination was done in bench scale and CSTR bioreactor (Continuous Stirred Tank Reactor). The effects of various parameters such as pH, temperature, time, supplemented substrates, method of inoculation of microbes, rpm were evaluated. Changes of microbial growth and protein contents were tested by using Optical Density (OD) and Makrokjeldal methods respectively. In end of examination, produced protein were extracted and lyophilized. The results showed that protein percentage in bacterial protein was than yeast protein but wet percentage in bacterial protein was low. Production value produced from tuna fish wastes was higher than (30-45 g/l) to Silver carp wastes (25-29 g/l) and cooked water (10-15 g/l). By adding supplemented substrates, production value has been increased. Candida utilis, in comparison other yeasts, has high activation. B.licheniformis has also had more activation than Bacillus subtilis. The results of the effect some parameters on fermentation showed that yeasts and Bacillus in pH= 5.4 and 32oC and pH=6.9 and 35oC were better than growth pH=6 and 25oC and pH=6.5 and 30oC respectively. Time of fermentation in batch and bioreactor was 54 and 21 hours respectively. High rpm has been caused increasing of microbial growth in bioreactor. The conclusion showed that with optimizing of the growth condition such as some parameters (pH, temperature, substrates and so on) produced SCP with high efficiency. However, produced SCP should be exanimated with other specific tests such as amino acid and fatty acid profiles, minerals, nucleic acids and so on. After full examination, this SCP as probiotic could be used in fish and poultry feed

Solution Behavior and Activity of a Halophilic Esterase under High Salt Concentration

Background: Halophiles are extremophiles that thrive in environments with very high concentrations of salt. Although the salt reliance and physiology of these extremophiles have been widely investigated, the molecular working mechanisms of their enzymes under salty conditions have been little explored. Methodology/Principal Findings: A halophilic esterolytic enzyme LipC derived from archeaon Haloarcula marismortui was overexpressed from Escherichia coli BL21. The purified enzyme showed a range of hydrolytic activity towards the substrates of p-nitrophenyl esters with different alkyl chains (n = 2−16), with the highest activity being observed for p-nitrophenyl acetate, consistent with the basic character of an esterase. The optimal esterase activities were found to be at pH 9.5 and [NaCl] = 3.4 M or [KCl] = 3.0 M and at around 45°C. Interestingly, the hydrolysis activity showed a clear reversibility against changes in salt concentration. At the ambient temperature of 22°C, enzyme systems working under the optimal salt concentrations were very stable against time. Increase in temperature increased the activity but reduced its stability. Circular dichroism (CD), dynamic light scattering (DLS) and small angle neutron scattering (SANS) were deployed to determine the physical states of LipC in solution. As the salt concentration increased, DLS revealed substantial increase in aggregate sizes, but CD measurements revealed the maximal retention of the α-helical structure at the salt concentration matching the optimal activity. These observations were supported by SANS analysis that revealed the highest proportion of unimers and dimers around the optimal salt concentration, although the coexistent larger aggregates showed a trend of increasing size with salt concentration, consistent with the DLS data. Conclusions/Significance: The solution α-helical structure and activity relation also matched the highest proportion of enzyme unimers and dimers. Given that all the solutions studied were structurally inhomogeneous, it is important for future work to understand how the LipC's solution aggregation affected its activity

Effects of the electronic threshold on the performance of the RPC system of the CMS experiment

Resistive Plate Chambers have a very important role for muon triggering both in the barrel and in the endcap regions of the CMS experiment at the Large Hadron Collider (LHC). In order to optimize their performance, it is of primary importance to tune the electronic threshold of the front-end boards reading the signals from these detectors. In this paper we present the results of a study aimed to evaluate the effects on the RPC efficiency, cluster size and detector intrinsic noise rate, of variations of the electronics threshold voltage

Machine Learning based tool for CMS RPC currents quality monitoring

The muon system of the CERN Compact Muon Solenoid (CMS) experiment includes more than a thousand Resistive Plate Chambers (RPC). They are gaseous detectors operated in the hostile environment of the CMS underground cavern on the Large Hadron Collider where pp luminosities of up to $2\times 10^{34}$ $\text{cm}^{-2}\text{s}^{-1}$ are routinely achieved. The CMS RPC system performance is constantly monitored and the detector is regularly maintained to ensure stable operation. The main monitorable characteristics are dark current, efficiency for muon detection, noise rate etc. Herein we describe an automated tool for CMS RPC current monitoring which uses Machine Learning techniques. We further elaborate on the dedicated generalized linear model proposed already and add autoencoder models for self-consistent predictions as well as hybrid models to allow for RPC current predictions in a distant future

RPC radiation background simulations for the high luminosity phase in the CMS experiment

The high luminosity expected from the HL-LHC will be a challenge for the CMS detector. The increased rate of particles coming from the collisions and the radioactivity induced in the detector material could cause significant damage and result in a progressive degradation of its performance. Simulation studies are very useful in these scenarios as they allow one to study the radiation environment and the impact on detector performance. Results are presented for CMS RPC stations considering the operating conditions expected at the HL-LHC

CMSRPC efficiency measurement using the tag-and-probe method

We measure the efficiency of CMS Resistive Plate Chamber (RPC) detectors in proton-proton collisions at the centre-of-mass energy of 13 TeV using the tag-and-probe method. A muon from a Z(0) boson decay is selected as a probe of efficiency measurement, reconstructed using the CMS inner tracker and the rest of CMS muon systems. The overall efficiency of CMS RPC chambers during the 2016-2017 collision runs is measured to be more than 96% for the nominal RPC chambers