Soluble Potassium Research Articles

A major conformational change of N-terminal helices of Bacillus thuringiensis Cry1Ab insecticidal protein is necessary for membrane insertion and toxicity.

Pore forming toxins rely on oligomerization for membrane insertion to kill their targets. Bacillus thuringiensis produces insecticidal Cry-proteins composed of three domains that form pores that kill the insect larvae. Domain I is involved in oligomerization and membrane insertion, whereas Domains II and III participate in receptor binding and specificity. However, the structural changes involved in membrane insertion of these proteins remain unsolved. The most widely accepted model for membrane insertion, the 'umbrella model', proposed that the α-4/α-5 hairpin of Domain I swings away and is inserted into the membrane. To determine the topology of Cry1Ab in the membrane, disulfide bonds linking α-helices of Domain I were introduced to restrict their movement. Disulfide bonds between helices α-2/α-3 or α-3/α-4 lost oligomerization and toxicity, indicating that movement of these helices is needed for insecticidal activity. By contrast, disulfide bonds linking helices α-5/α-6 did not affect toxicity, which contradicts the 'umbrella model'. Additionally, Föster resonance energy transfer closest approach analyses measuring distances of different points in the toxin to the membrane plane and collisional quenching assays analysing the protection of specific fluorescent-labeled residues to the soluble potassium iodide quencher in the membrane inserted state were performed. Overall, the data show that Domain I from Cry1Ab may undergo a major conformational change during its membrane insertion, where the N-terminal region (helices α-1 to α-4) participates in oligomerization and toxicity, probably forming an extended helix. These data break a paradigm, showing a new 'folding white-cane model', which better explains the structural changes of Cry toxins during insertion into the membrane.

Two novel phosphorus/potassium-degradation bacteria: Bacillus aerophilus SD-1/Bacillus altitudinis SD-3 and their application in two-stage composting of corncob residue

For effective utilization of corncob residue to realize green circular production, using composting to obtain a high-quality and low-cost biomass fertilizer has become a very important transformation avenue. In this paper, two novel phosphorus/potassium-degradation bacterial strains were isolated from tobacco straw and identified as Bacillus aerophilus SD-1/Bacillus altitudinis SD-3 (abbreviated as SD-1/SD-3). These identified two novel bacteria SD-1/SD-3 show that the soluble phosphorus content of SD-1/SD-3 reached 360.89mgL-1/403.56mgL-1 in the shake flask test, and the mass concentration of soluble potassium is 136.56mgL-1/139.89mgL-1. In addition, the Laccase (Lac), Lignin peroxidase (LiP), and Manganese peroxidase (MnP) activities of SD-1 and SD-3 are 54.45UL-1/394.84UL-1/222.79UL-1 and 46.27UL-1/395.26UL-1/203.98UL-1 respectively, with the carboxy-methyl cellulase (CMCase) of 72.07UmL-1 and 52.69UmL-1. Meanwhile, the effects of three different combinations of cultures, i.e., no inoculation (K1), inoculation of SD-1/SD-3 on day 21 (K2) and on day 0 (G) are investigated to understand the influence on the degradation degree of corncob residue compost. The results of K2 compost treatment showed that the effective P/K content increased nearly 3.1/2.4 times, the degradation of cellulose/lignin was 49.1/68.0%, and the germination rate was 110.23%, which were higher than other experiment groups K1/G. In conclusion, knowledge of this paper will be very useful for the industrial sector for the treatment of complex corncob residue.

Spatio-temporal distribution of particulate matter and wood-smoke tracers in Temuco, Chile: A city heavily impacted by residential wood-burning

Temuco, like most Southern Chile cities, has a long-standing air pollution problem due to residential wood heating. Here, we study the temporal and spatial distribution of PM2.5 and the biomass-burning tracers levoglucosan and water soluble potassium (Ksol). PM2.5 samples were collected at 40 sites throughout the city and sampled four times in four different sessions between 2017 and 2018. Large concentrations were observed for all species, particularly in winter. Signs of spatial and temporal correlation were observed from multilevel models for the different concentrations and ratios. Ratios of levoglucosan and Ksol to PM2.5 were lower in summer. Spatial clustering was observed both from spatial autocorrelation tests and kriging, with clusters of higher ratios for of all three species (comparing rotating to central site) observed in some neighborhoods. Clusters correlated with lower socioeconomic status (SES), which may reflect population density and lower quality stoves. Clusters of higher Ksol to PM2.5 ratios in some neighborhoods were moderately correlated with higher SES, which may reflect the use of better-quality stoves (e.g., pellets). The current work provides a case study and example of the investigation of wood burning as an air pollution source in a city where many inhabitants use wood as a fuel for heating and cooking. It reveals key temporal and spatial patterns which can assist the design of mitigation strategies.

Synergistic strategy of the phosphorus anode decorated by LiF and combined with KFSI-based electrolyte against shuttle effect of dissoluble polyphosphides for boosting potassium-storage performance

Phosphorus is a promising anode material for potassium-ion batteries due to the highest theoretical-specific capacity among all the proposed anode materials. So far, it is considered to have similar disadvantages to silicon anode, such as poor electronic conductivity and huge volumetric change, thus, lots of efforts have been devoted to synthesizing phosphorus/carbon hybrids. However, the electrochemical performance is still unsatisfied, due to the unclear capacity decay mechanism. Here we reveal that soluble potassium polyphosphides are generated during potassiation process and shuttle to the counter electrode where the side effects occur, leading to the loss of active phosphorus and the failure of counter electrode. To address this issue, we developed the P/CNT-LiF electrode in combination with the replacement of conventional KPF 6 by potassium bis(fluorosulfonyl)imide (KFSI) in electrolyte, in which KFSI contributes to the formation of stable and tough solid electrolyte interface (SEI), meanwhile LiF can prevent polyphosphides from diffusing to the electrolyte before and after the formation of SEI. Thus, the thin, stable and uniform SEI layer can be generated at the surface of the electrode particles, inhibiting the polyphosphides’ shuttle, contributing to the improved initial coulomb efficiency (73.7%) and reversible specific capacity (507.6 mAh g −1 after 100 cycles at 50 mA g −1 ).

Research on the strengthening mechanism of potassium leaching process to potassium feldspar

The technology of transforming potassium minerals from potassium feldspar into soluble potassium by acid hydrolysis, and discussed the leaching mechanism of potassium in the process of leaching. The results showed that the dissolution efficiency of potassium was 76 % under the conditions of 8.05 g·g−1 70 wt% H2SO4, 0.5 g·g−1 ammonium fluoride, 130 ± 2 °C and a reaction time of 2 h. The compound effect is much greater than the acid effect in the process of acid leaching. The ionization-hydrolysis model of potassium leaching is built, [K+] increases with the addition of [H+] and each side reaction coefficient. Without considering the precipitation effect of K2SiF6 and K3AlF6, [K+] is subjected to the joint action of [H+] and [F−]. When pH is constant, [K+] goes up as [F−] increases; when [F−] is constant, [K+] increases with the rise of [H+]. But the increase of [K+] in the solution intensifies the occurrence of side reaction of potassium, forming precipitation and decreasing the presence of soluble potassium in solution.

Volatile potassium transfer behavior in carbon matrix and its effect on char gasification

Coal catalytic gasification is one of the effective ways to produce natural gas from coal. However, high cost and low recovery efficiency of catalyst increase the cost of catalytic gasification, which has become a restrictive factor for large-scale promotion of coal catalytic gasification. Therefore, the study on the migration behavior of potassium-based catalysts in the gasification process is of great significance for catalysts recovery. To understand the volatilization behavior between potassium and carbon matrix, the experiments were carried out in high temperature stage microscope (HTSM) and fixed-bed reactor. The migration of volatile potassium between particles was analyzed by SEM-EDS, while the chemical fraction of potassium species was determined by AAS, and the surface elements of the samples was investigated by XPS. The results showed that potassium would volatile at 765-770℃, C/K≈6.2–9.5(wt%), which would be adsorbed by the other char particles, leading to an increasing of the content of soluble potassium and ion-exchanged potassium, promoting carbon conversion in a limited effect and a decreasing of hydroxyl functional groups on the char particles. Meanwhile, the potassium content was proportional to the migration distance, the migration distance was about 720–800 μm at maximum under HTSM. The migration of potassium at high temperature caused the formation of liquid phase around the surface of char particles, which would prevent the contact between the gasifier agent and char particles and increase mass transfer resistance, thus preventing the increase of particle carbon conversion. In addition, no obvious liquid phase formation occurred at 800 °C in SFA-K, indicating that the formation of potassium-containing liquid phase and the volatilization of potassium at 800 °C were directly related to the carbon in the char.

Revitalizing coastal saline-alkali soil with biochar application for improved crop growth

The wheat straw biochar has well pronounced effects on the coastal saline-alkali soil remediation/health. The soil water content in saline-alkali soil increased by 12.4–16.6% (2014), 18.1–63.4% (2015), 23.9–42.6% (2016) with 0, 20, 40, and 60 t ha−1 application of wheat straw biochar. The different chemical properties like pH, CEC (cation exchange capacity) and SOM (soil organic matter) ranged between 0.2 and 3.1, 6.7–82.0% and 12.6–139.6%, respectively with biochar application during three years of field experiment. The TSS (total soluble salt) of different biochar treatments in the soil decreased by 15.9–23.7% (2014), 28.6–54.6% (2015), 11.7–42.2% (2016) compared with control. The exchangeable/soluble cations like Calcium (Ca), Magnesium (Mg), chlorine (Cl) and Sodium (Na) concentration showed the similar trend as that of TSS. The soil soluble potassium (K) concentration significantly increased by 82.5–233.1% (2014), 65.3–228.2% (2015), 19.2–233.8% (2016) compared with control, which mainly originated from biochar. The wheat straw biochar application improves the coastal saline-alkali soil health and environment, which promoted the crop growth. The biochar amendment improved the soil properties with decrease in the salt concentration that showed biochar potential to improve/remediate the saline alkali soil.

Silicate minerals - Potential source of potash - A review

The third crucial macronutrient required for the development and growth of plants in addition to nitrogen and phosphorous is potassium. The quantity of soluble potassium in soil that could be directly taken up by plants is less and present in the form of evaporite deposits situated in countries lying in the Northern hemisphere such as Canada, Belarus, Israel, USA and Russia. All other countries are dependent on imports from these countries to fulfil their potash requirement. But a major part of potassium exists in insoluble form as silicate minerals abundantly in these countries which can compensate for the potassium deficit. Mostly feldspar and feldspathoid from the tectosilicate group and micaceous minerals from the phyllosilicate group are the common potassium bearing silicates containing 5–15% K2O. Tectosilicates are framework silicates in which potassium is present in the three-dimensional silicate tetrahedra. Phyllosilicates are sheet silicates having a two-dimensional parallel sheet structure and potassium ions are located in the interlayers of the silicate structure. Various processes have been adopted to release the potassium from these silicate resources such as bio-leaching using various algal, bacterial and yeast strains, acid leaching with different acids of varying concentrations, base leaching with diverse strategies and roast-leach studies with alkali and alkaline salts to optimise the recovery. This review summarizes versatile methodologies that have been approached and the scope of various works that could be further accomplished.

Whole-Genome Sequencing and Potassium-Solubilizing Mechanism of Bacillus aryabhattai SK1-7.

To analyze the whole genome of Bacillus aryabhattai strain SK1-7 and explore its potassium solubilization characteristics and mechanism, thus providing a theoretical basis for analyzing the utilization and improvement of insoluble potassium resources in soil. Genome information for Bacillus aryabhattai SK1-7 was obtained by using Illumina NovaSeq second-generation sequencing and GridION Nanopore ONT third-generation sequencing technology. The contents of organic acids and polysaccharides in fermentation broth of Bacillus aryabhattai SK1-7 were determined by high-performance liquid chromatography and the anthrone sulfuric acid method, and the expression levels of the potassium solubilization-related genes ackA, epsB, gltA, mdh and ppc were compared by real-time fluorescence quantitative PCR under different potassium source culture conditions. The whole genome of the strain consisted of a complete chromosome sequence and four plasmid sequences. The sequence sizes of the chromosomes and plasmids P1, P2, P3 and P4 were 5,188,391 bp, 136,204 bp, 124,862 bp, 67,200 bp and 12,374 bp, respectively. The GC contents were 38.2, 34.4, 33.6, 32.8, and 33.7%. Strain SK1-7 mainly secreted malic, formic, acetic and citric acids under culture with an insoluble potassium source. The polysaccharide content produced with an insoluble potassium source was higher than that with a soluble potassium source. The expression levels of five potassium solubilization-related genes with the insoluble potassium source were higher than those with the soluble potassium source.

Fractions of Soil Potassium and their Depthwise Distribution under Long-Term Nutrient Management Practices in Semiarid Alfisols in India

A field experiment was conducted on a long-term experimental plot during two consecutive rabi seasons of 2016-17 and 2017-18 at the college farm, College of Agriculture, Rajendranagar, Hyderabad, PJTSAU. The experimental soil was non-saline, neutral in reaction with sandy loam texture. Different forms of soil potassium were studied with six different nutrient management practices in randomized block design with four replications. The results of pooled data of two years study revealed that significantly higher contents of water soluble potassium (17.77 mg kg-1), exchangeable potassium (568 mg kg-1), nonexchangeable potassium (999 mg kg-1) and Total potassium (1.80%) in surface layer (0-15 cm) at flowering were recorded with integrated application of 50% N through FYM and 50% N through chemical fertilizers and it was on par with treatment applied 100% RDF through chemical fertilisers and significantly superior over other organic nutrient management treatments. A similar trend was observed at all soil depths (15-30, 30-45, 45-60 cm) and all the contents were decreased from flowering to harvest. All potassium forms decreased with increasing the depth except non exchangeable K. All the fractions were found to be significant in surface layer (0-15 cm). The contribution of different forms of soil K to Total K was in the order of non-exchangeable K> exchangeable K> water soluble K and similar trend was observed in all soil layers.

Potassium Forms for Main Soil Orders in The North of Iraq

Fifteen soil samples were collected from five locations in the North of Iraq from three surface genetic horizons for the five locations [Semeel (Vertisols), Imerik (Aridisols), Gerderash (Inceptisols), Perdi (Aridisols) and Wermawa (Mollisols)] to study the forms of potassium and its distribution with the depth. All studied soils are calcareous and non-saline soils contain low organic matter. The studied forms of K in the surface horizons of the studied soils (soluble, exchangeable, available, non-exchangeable, mineral and total potassium) were ranged between (12 – 40, 82 – 229, 97 – 246, 656 – 3800, 462 – 2933 and 1200 – 5400) mg kg-1 respectively, while in the intermediate (A and A1) soil horizons were (5 –26,  67 – 214 ,  72 –  216 ,  676 – 3040 , 709 – 2048  and  1700 – 5200) mg kg-1 respectively and in the third horizon of studied soils were (4 – 14 ,  68 – 191, 70 – 186 ,  345 – 3232 ,  419 – 4516  and 1700 – 5800) mg kg-1 respectively, this illustrates the amount of soluble, exchangeable, available (soluble + exchangeable), non-exchangeable decreases with the depth. The constituted percent of the soluble, exchangeable; available; nonexchangeable and mineral potassium from total-K in all pedons equal to 0.469; 4.185 ; (4.538); 52.141 and 43.318 respectively. Correlation study illustrates positively and significantly correlated between total potassium with exchangeable, available, non-exchangeable, mineral, while positively and significant relation demonstrate between exchangeable, available, non-exchangeable with silt content in the soils, but positively relation found between soluble potassium with pH and negatively to EC. The high amount of soluble K found in Perdi pedon (Aridisols) but higher amount of the exchangeable, non- exchangeable, available and total-K demonstrate in Imerik pedon (Aridisols) while large amount of mineral-K shown in Gerderash pedon (Inceptisols)

Physiological-biochemical responses of wheat to blending controlled-release potassium chloride and soluble potassium chloride

The crop yields and potassium use efficiency (KUE) could be enhanced by controlled-release potassium chloride (CRK), yet the effects of blending 50 % CRK and 50 % soluble potassium chloride (BBF), on crop physiological-biochemical characteristics were not reported. We carried out a five-year field experiment during 2014–2019 with five K fertilization treatments in a completely randomized block design using wheat (Triticum aestivum. L.) as a testing crop. The results showed that: compared with K1 (full-dose of soluble potassium chloride (KCl)) treatment, the SPAD value and photosynthetic rate of BBF1 (full-dose of BBF) treatment were increased by 7.3–12.2 % and 36.5–59.0 %, respectively, at jointing and grain-filling stages; the auxin and abscisic acid in leaves and roots of BBF1 treatment proliferated by 14.0 %, 27.2 % and 19.5 %, 25.0 %, respectively, at jointing stage; the root total volume and surface area of BBF1 treatment were sharply risen by 80.2 % and 38.8 %, respectively, at jointing stage. The yield and net profit of BBF1 treatment increased by 5.0–19.7 % and 7.2–28.7 %, respectively. With K fertilization rate reduced by 30 %, BBF2 treatment produced almost the same yield as with the 100 % rate of monotypic soluble KCl treatment. This study demonstrated that combining CRK and soluble KCl improved the root physiological characteristics and endogenous hormones of wheat and consequently increased wheat yield.

Electrolyte modulation of BiPS4 concurrently suppressing the Bi coarsening and polysulfide shuttle effect in K-ion batteries

Emerging electrode materials for next generation batteries are consciously designed to contain multi-component active materials that can function synergistically to perform several electrochemical and structural tasks for much improved battery performance. Herein, bismuth phosphorus tetrachalcogenide (BiPS4) is introduced as an excellent anode for potassium-ion batteries. It exhibits a tunnel structure to provide exceptional ion/electron pathways and mechanical integrity against severe volume variations. Abnormal growth and aggregation of Bi nanoparticles and shuttling of the intermediate soluble potassium polysulfides are detected for the first time during the potassiation/depotassiation processes. Rational construction of BiPS4-carbon nanotube hybrid with robust chemical bonds, along with electrolyte modification during the electrochemical tests successfully hinder these two detrimental phenomena. This is revealed by various characterization techniques and theoretical calculations. Consequently, the hybrid delivers a high initial discharge capacity (863 mAh g−1 at 0.05 A g−1) and Coulombic efficiency (81.9%), excellent cycling stability (554 mAh g−1 after 300 cycles at 0.2 A g−1 and 489 mAh g−1 after 600 cycles at 1 A g−1), and superb rate capability (498 mAh g−1 at 2 A g−1) through multiplex reversible conversion and alloying reactions.

Screening and Preliminary Identification of Soil Potassium and Phosphorus-hydrolyzing Bacteria WP1-3

In order to screen the strains with Potassium and phosphorus-releasing bacteria from the soil, the potassium-dissolving medium was used for preliminary screening, and the transparent circle method was used for re-screening. The content of soluble potassium was determined by sodium tetraphenylborate method, and the content of phosphorus was determined by anticolorimetric method of molybdenum and antimony. The strains were identified by morphological, biochemical and molecular biology. The results showed that ten strains with potassium-solubilizing function were obtained by preliminary screening of potassium solubilizing medium. The re-screening by transparent circle method showed that WP1-3 strain had the strongest potassium-solubilizing ability, with D/d value of 1.33. WP1-3 strains of decomposition of soluble potassium content is 22.918 mg/L, decompose inorganic phosphorus and organic phosphorus ability is 4.443 mg/L and 22.408 mg/L, respectively. Identifying morphological and biochemical identification showed that WP1-3 strains was gram-negative bacteria, not produce spore, the nitrogen content of WP1-3 strain increased after detection and culture for 3d and 7d were 10.825 and 38.521 mg/L. The 16SrDNA size was 1351bp, the ribosomal database comparison showed that WP1-3 strain was 99.8% similar to Rhizobium. Therefore, the WP1-3 strain belongs to the rhizobia genus.

Potassium-Solubilizing Activity of Bacillus aryabhattai SK1-7 and Its Growth-Promoting Effect on Populus alba L.

In the present study, the potassium-solubilizing characteristics of Bacillus aryabhattai SK1-7 and its growth-promoting effect on plants were evaluated to determine the biotechnological potential of this bacterium in alleviating soil potassium deficiency. The potassium-solubilizing activity of SK1-7 was determined by fermentation. Additionally, the fermentation broth was determined by flame spectrophotometry. The aluminum and silicon ion contents in SK1-7 fermentation broth were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) after digestion with nitric acid hydrogen peroxide hydrofluoric acid. Scanning electron microscopy (SEM)-based observations were performed to assess the morphological changes in potassium feldspar surfaces digested by potassium-solubilizing bacteria. In addition, the effects of SK1-7 on plant growth and soil physical and chemical properties were analyzed. After incubation for 7 days in a potassium-solubilizing medium, the concentration of potassium dissolved reached 10.8 μg/mL and the percentage of potassium released was 32.6%. The pH rapidly decreased from 7.2 to 4.321 within the first day and then further decreased to 3.90 after 7 days. After 7 days, the concentrations of aluminum and silicon in the fermentation broth were 1.01 and 24.19 μg/mL, respectively. The growth promotion assay results showed that SK1-7 has good growth-promoting effects on poplar and can effectively improve the available potassium content in poplar rhizosphere soil. The SK1-7 strain can effectively dissolve insoluble potassium to release soluble potassium ions and clearly promotes the growth of poplar after being applied to soil. Thus, the SK1-7 strain is a potassium-solubilizing microorganism with good application prospects.

Trash Mulch and Weed Management Practice Impact on Some Soil Properties, Weed Dynamics and Sugarcane (Saccharum officinarum L.) Genotypes Plant Crop Productivity

The effects of sugarcane trash mulch rate and weed management practices on some soil properties, weed dynamics and productivity of sugarcane genotypes plant crops were investigated at Badeggi, Nigeria in 2016 and 2017. The results revealed that application of 6 t ha−1 mulch produced comparable soil organic carbon content but lower weed dry matter to 9 t ha−1 which significantly added more total nitrogen, available phosphorus and soluble potassium to the soil. Application of PE diuron plus POE 3—maize force, resulted in a comparable weed dry matter to PE diuron plus POE 3—maize force plus 2 MHW. Similarly, PE diuron plus POE 3—maize force, 5 MHW and PE diuron plus POE 3—maize force plus 2 MHW produced comparable stalks and Brix content. Also, 5 MHW generated taller sugarcane plants. Application of PE diuron plus POE 3—maize force proved equally effective as 5 MHW in contributing the highest cane yield. Highest soil total nitrogen and available phosphorus were found in NCS 001. Lower weed dry matter was found in Bida local, and taller stalks, maximum cane girth, higher Brix content and cane yield were observed in NCS 001. In conclusion, application of 9 t ha−1 trash mulch with 5 MHW or PE diuron plus POE 3—maize force plus 2 MHW or PE diuron plus POE 3—maize force effectively controlled weeds, increased stalk height, cane girth, Brix content and cane yield of sugarcane, especially NCS 001.

Dietary macro- and micro-nutrients intake adequacy at 6th and 12th month post-bariatric surgery

BackgroundBariatric surgery (BS) is considered as an effective solution to control morbid obesity. Food restrictions resulting from the operation may decrease dietary nutrient intakes, particularly during the first year after BS. This study mainly aimed to assess the adequacy of dietary nutrient intakes at 6th and 12th month after BS.MethodOf the severely obese participants in the Tehran obesity treatment study in 2015–2016, 58 patients undergoing Roux-En-Y gastric bypass (N = 16) or sleeve gastrectomy (N = 42) were selected from Tehran Obesity Treatment Center. To assess the patients’ dietary intake, a three-day, 24-h dietary recall was obtained on three unscheduled days (two non-consecutive weekdays and one weekend day) at 6th and 12th month after BS. To evaluate the adequacy of nutrient intake, the patients’ intakes were compared to the current dietary reference intakes (DRIs), including estimated average requirements (EAR) or Adequate Intakes (AI).ResultsThe mean age of the participants (71% women) undergoing BS was 37 ± 8 years. Anthropometric parameters significantly decreased at the 12th month after BS. The percentage of energy from carbohydrate intake increased significantly between the 6th and 12th month after BS (P = 0.04). The mean ± SD of protein intake was lower than the recommended dosage with a dramatic decrease from 45 ± 30 to 31 ± 15 (g/day) between the two intervals (P = 0.001). The mean intake of saturated fatty acid (SFA) decreased dramatically (P < 0.001) from 6 to 12 month; however, the median intake of n3-polyunsaturated fatty acid (n3-PUFA) intake increased (P = 0.02). None of the participants showed nutrient intake adequacy in terms of biotin, fat soluble vitamins, pantothenic acid, potassium, and zinc. Moreover, less than 10% of the participants showed nutrient intake adequacy in terms of folate, magnesium, manganese, and calcium according to DRIs during the both intervals after BS.ConclusionBariatric surgery can reduce dietary intakes, which is more obvious 12 months after the surgery. Out of 21 micronutrients, nearly all could not met the EAR and were received < 50%, also had significant reduction from the 6th to12th month after surgery.

Evaporation Stage of Paleo‐saline Lake in the Sichuan Basin, China: Insight from Fluid inclusions in Halite

AbstractSichuan Basin is one of the most important marine–salt forming basins in China. The Simian and Triassic have a large number of evaporites. The Triassic strata have found a large amount of polyhalite and potassium‐rich brine. However, no soluble potassium salt deposit were found. In this study, the halite in well Changping 3 which is located at the eastern part of the Sichuan basin was studied using the characteristics, hydrogen and oxygen isotopes of the fluid inclusion in halite to reconstruct the paleoenvironment. The salt rocks in well Changping 3 can be divided into two types: grey salt rock and orange salt rock. The result shows that the isotopic composition of the halite fluid inclusion is distinct from the global precipitation line reflecting that the salt formation process is under strong evaporation conditions and the climate is extremely dry. At the same time, compared with the hydrogen and oxygen isotopes of brine in the Sichuan Basin and the hydrous isotope composition of the inclusions in the salt inclusions of other areas in China, it is shown that the evaporation depth of the ancient seawater in the Sichuan Basin was high and reached the precipitation of potassium and magnesium stage.

Origin and depositional paleoenvironment of Triassic polyhalite in the Jialingjiang Formation, Sichuan Basin

The Sichuan Basin contains the most prolific marine potash salt deposits in China. Although a vast amount of polyhalite has been found in the Triassic Jialingjiang Formation, the production of soluble potash deposits has yet to begin. The origin and sedimentary environment of polyhalite has remained unclear, and this information could have a significant economic impact. The recent discovery of protogenetic polyhalite co-existing with halite crystals in cores from the early Triassic Jialingjiang Formation in eastern Sichuan Basin provides vital clues to its origin and depositional environment. Two types of polyhalite have been identified, through the examination of sedimentary textures and fabrics, mineral composition and contents, and major and trace elements from cores. The first type is protogenetic polyhalite, which co-exists and is commingled with halite crystals. The second type is secondary in origin with a radiating texture and was formed by the metasomatism of gypsum. Triassic polyhalite and halite was deposited during periods of freshwater and sylvite-saturated, evaporated seawater mixing. Further dilution of the freshwater resulted in gypsum precipitation among the halite crystals. After periods of desalination, increasing evaporation leads to the formation of highly concentrated and dense brines that are rich in potassium and magnesium. These heavy brines sink downward through intercrystalline pores and fractures, replacing gypsum with polyhalite through metasomatism. These sequential phenomena occur because the Triassic marine basins were relatively small and tectonically active. Although these shallow, small salt basins can have a fast concentration rate, they can be easily desalinated by the peripheral freshwater input in an overall arid but fluctuating arid and wet climate. The alternating periods of evaporation and desalination are responsible for the formation of soluble potassium salt deposits. Our proposed mechanisms provide useful information for understanding the distribution of polyhalite. These mechanisms can be used to guide future exploration and production of Triassic marine potash salts in the periphery of the Tethys Ocean.

Molecular Markers in Ambient Air Associated with Biomass Burning in Morelos, México

Atmospheric particles with an aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) were collected at two sites located in the urban area of the city of Cuernavaca (Morelos) during a season when a large number of forest fires occurred. Three dicarboxylic acids (malonic, glutaric and succinic) and levoglucosan were analyzed by liquid chromatography coupled with mass spectrometry (ESI-Q-TOF) and soluble potassium (K+) was analyzed by ion chromatography. The concentration of PM2.5 increased on the days when the highest number of forest fires occurred. A strong correlation was observed between levoglucosan and K+, confirming the hypothesis that both are tracers of biomass burning (r = 0.57, p &lt; 0.05). Levoglucosan (average 367.6 ng m−3, Site 2) was the most abundant compound, followed by succinic acid (average 101.7 ng m−3, Site 2), glutaric acid (average 63.2 ng m−3, Site 2), and malonic acid (average 46.9 ng m−3, Site 2), respectively. The ratio of C3/C4 concentrations ranged from 0.5 to 1.2, with an average of 0.8, which suggests great photochemical activity in the Cuernavaca atmosphere. The ratio of K+/levoglucosan concentrations (0.44) indicates that open fires are the main source of these tracers. The positive correlations between PM2.5 and levoglucosan and succinic and malonic acids suggest that such compounds are contributing to secondary organic aerosol particle formation.