End Of Incubation Period Research Articles

The detection of pomegranate (Punica granatum L.) peel apoptotic effects using AgNOR staining in MDA-MB-231.

In present study, it was purposed to determine the in vitro effect of the extract obtained from the pomegranate (Punica granatum L.) peel on the breast cancer cell line. MDA-MB-231 cells were exposed to pomegranate peel extract (PoPx) at 37°C and 5% CO2 for varying durations (24 and 48h) and doses (25 and 50μg/mL). At the end of the incubation periods, argyrophilic nucleolus organizer regions (AgNOR) protein status, cell viability/apoptosis and cell cycle of MDA-MB-231 cells were examined in the Muse Cell Analyzer device. Cell viability was observed to be decreased when the groups treated with PoPx were compared with the control group. The group in which apoptosis was observed with the highest value was 50μg/mL PoPx group (p<0.05). In the cell cycle test, the number of cells in the G0/G1 stage was found to be significantly higher in the 25μg/mL PoPx group compared to the control and 50μg/mL PoPx groups at the end of the 24-h incubation period (p<0.05) The results also supported cell cycle and apoptosis, and at the end of 24h, Total AgNOR area(TAA)/Total nuclear area (NA) ratio and AgNOR numbered decreased on the 50μg/mL PoPx group and were found to be statistically significant compared to the control group (p<0.05). Consequently, it was determined that PoPx increased apoptosis on breast cancer cells by various mechanisms and inhibited cell viability/cell growth. This study showed that the widespread consumption of PoPx may be effective in preventing cancer formation and slowing its progression.

Reduction in carbon dioxide and methane production of tropical peatlands due to coal fly-ash application

Tropical peatlands with very high organic carbon (C) contents have the potential to be a source of carbon dioxide (CO2) and methane (CH4) production. Therefore, the management of tropical peatlands is essential to prevent peat decomposition and to reduce the production of CO2 and CH4. We added different amounts of coal fly-ash (CFA) (0, 25, 50, 75, 100 and 125 Mg ha−1) to tropical peats in a laboratory study to quantify changes in CO2 and CH4 production in response to the application of CFA. The amounts of CO2 and CH4 produced by the mixtures of peats and CFA over 90 days were monitored on weekly basis. Peat pH, concentrations of hot-water soluble C, calcium and iron were also measured at the end of incubation period. Results of study revealed that the application of CFA up to 50 Mg ha−1 did not change the production of CO2 and CH4, while the application of CFA by 50–125 Mg ha−1 reduced 12–24% of CO2 and 9–15% of CH4. The decrease in the production of CO2 and CH4 due to the relatively high amount of CFA application was related to the decrease in the amount of hot soluble organic C and the increase in the concentrations of Ca and Fe. This study demonstrates the potential of CFA as waste materials from coal processing of power plants in reducing CO2 and CH4 emissions of tropical peatlands.

The potential role of neopterin in Covid-19: a new perspective.

Neopterin (NPT) is a member of pteridines group, synthesized by macrophages when stimulated by interferon gamma (INF-γ). NPT is regarded as a macrophage stimulation indicator, marker of cellular immune activation and T helper 1 (Th1) type 1 immune response. Here, we aimed to provide a view point on the NPT features and role in Covid-19. Serum NPT level is regarded as an independent prognostic factor for Covid-19 severity, with levels starting to increase from the 3rd day of SARS-CoV-2 infection, being associated with severe dyspnea, longer hospitalization period and complications. Also, early raise of NPT reflects monocytes/macrophages activation before antibody immune response, despite the NPT level may also remain high in Covid-19 patients or at the end of incubation period before the onset of clinical symptoms. On the other hand, NPT attenuates the activity of macrophage foam cells and is linked to endothelial inflammation through inhibition of adhesion molecules and monocytes migration. However, NPT also exerts anti-inflammatory and antioxidant effects by suppressing NF-κB signaling and NLRP3 inflammasomes. NPT can be viewed as a protective compensatory mechanism to counterpoise hyper-inflammation, oxidative stress, and associated organ damage.

A Staged Approach to Erosion Analysis of Wind Turbine Blade Coatings

The current wind turbine leading-edge erosion research focuses on the end of the incubation period and breakthrough when analysing the erosion mechanism. This work presented here shows the benefits of splitting and describing leading-edge erosion progression into discrete stages. The five identified stages are: (1) an undamaged, as-new, sample; (2) between the undamaged sample and end of incubation; (3) the end of incubation period; (4) between the end of incubation and breakthrough, and (5) breakthrough. Mass loss, microscopy and X-ray computed tomography were investigated at each of the five stages. From this analysis, it was observed that notable changes were detected at Stages 2 and 4, which are not usually considered separately. The staged approach to rain erosion testing offers a more thorough understanding of how the coating system changes and ultimately fails due to rain droplet impacts. It is observed that during microscopy and X-ray computed tomography, changes unobservable to the naked eye can be tracked using the staged approach.

Advance on the infectivity of SARS-CoV-2 infection at different stages

The studies on infectiousness of person infected with SARS-CoV-2 at different stages of illness are an important basis for making effective prevention and control measures such as investigating the infectious source, determining the scope of close contacts and the timing of case isolation. This review discusses the infectiousness of cases infected with SARS-CoV-2 in the incubation period, symptomatic period and convalescent period by reviewing national and international literatures, technical and professional guidelines. Existing researches suggest that the infectious viruses could be isolated at the end of the incubation period as well as since illness onset, and viral load in upper respiratory tract swabs reached the peak on day 4-6 after illness onset and thereafter began to decline, implying the infectiousness was relatively strong at the end of incubation period and within one week after illness onset. Although there were a few cases who tested positive for SARS-CoV-2 after recovery, no evidence was found to indicate these cases can cause the transmission.

Fasciola hepatica induces weak NETosis and low production of intra- and extracellular ROS in exposed bovine polymorphonuclear neutrophils

Fasciola hepatica is the causative agent of fasciolosis, a worldwide distributed zoonotic disease, leading to hepatitis in humans and livestock. Newly excysted juveniles (NEJ) of F. hepatica are the first invasive stages to encounter leukocytes of host innate immune system in vivo. Among leukocytes, polymorphonuclear neutrophils (PMN) are the most abundant granulocytes of blood system and first ones to migrate into infection sites. PMN are able to cast neutrophil extracellular traps (NETs), also known as NETosis, consisting of nuclear DNA, decorated with histones, enzymes and antimicrobial peptides, which can entrap and eventually kill invasive parasites. Given that only few large parasitic helminths have been identified as potent NETosis inducers, here we studied for first time whether different F. hepatica stages can also trigger NETosis. Therefore, isolated bovine PMN were co-cultured with viable F. hepatica-NEJ, -metacercariae, -eggs and soluble antigen (FhAg). Interestingly, all stages failed to induce considerable levels of NETosis as detected by immunofluorescence- and scanning electron microscopy (SEM) analyses. NEJ remained motile until the end of incubation period. In line, NETosis quantification via nuclear area expansion (NAE) analysis revealed NEJ as weak NETosis inducers. However, bovine PMN frequently displaced towards motile NEJ and were found attached to NEJ surfaces. Functional PMN chemotaxis assays using vital F. hepatica-NEJ revealed a slight increase of PMN migration when compared to non-exposed controls. Additional experiments on intra- and extracellular reactive oxygen species (ROS) production revealed that soluble FhAg failed to induce ROS production of exposed PMN. Finally, mitochondrial oxygen consumption rates (OCR), extracellular acidification rates (ERAC) and proton production rates (PPR) were not significantly increased in FhAg-stimulated PMN. In summary, data suggest that F. hepatica might effectively evade PMN activation and NETosis by secreting parasite-specific molecules to either resolve NETs or to impair NETosis signaling pathways. We call for future molecular analysis not only on F. hepatica-derived NETosis modulation but also on its possible role in fasciolosis-associated pathology in vivo.

Identification of Potential Pathogen Bacteria Causing Tuber Rot in Porang (Amorphophallus muelleri Blume)

Tuber rot has been reported as one of the limiting factors to porang ( Amorphophallus muelleri Blume) tuber production. Bacterial infection is one of the main causes of tuber rot during storage. In this study, a total of seven bacterial isolates obtained from porang tubers were tested for their potency to cause rotting on porang tubers. Porang tubers were immersed in bacterial suspension and incubated for 14 days. The physical properties of the tubers such as texture and color, and the chemical properties such as reducing sugar and ethanol content were determined at the end of incubation period. All infected tubers were soft, slimy and darker. Two isolates, T4 and T9A, had the highest potency to cause tuber rot indicated by the significantly higher reducing sugar content (14.38 and 15.32 mg/ml) and higher ethanol content (32.17 and 35.05%) compared to control tubers which were not infected with bacteria. Both isolates were identified as Bacillus altitudinis and Pseudomonas stutzeri , respectively, based on 16S rDNA sequence analysis.

Sulfur, Na2-EDTA and their mixture effects on phosphorus release from cow bone char in P-poor sandy soil

Abstract The high cost and environmental problems related to the production of phosphate fertilizers as well as their excessive and continuous applications represent great challenges in modern agriculture. Therefore, we conducted an incubation experiment using sandy soil to evaluate the effects of elemental sulfur, disodium ethylene diamine tetra-acetic acid (Na2-EDTA) and their mixture with cow bone char as well as incubation periods on changes of phosphorus (P) availability, water soluble P, soil pH, electrical conductivity (EC), soluble calcium (Ca) and soluble sulfate (SO4). Applying sulfur (S), Na2EDTA and their mixture with cow bone char improved significantly phosphorus availability in soil, Olsen-P value increased from 7.65 mg kg−1 (control) to 12.20 mg kg−1 (cow bone char + sulfur), 12.80 mg kg−1 (cow bone char + Na2-EDTA) and 13.07 mg kg−1 (cow bone char + sulfur + Na2-EDTA) at the end of incubation periods While, cow bone char + sulfur + Na2-EDTA treatment lead Olsen-P to decline significantly with increasing incubation periods. Amending soil by sulfur with cow bone char treatment caused significant increase in the Olsen-P with increasing incubation periods. Cow bone char + sulfur and cow bone char + Na2-EDTA showed non-significant differences in Olsen-P. Because of the increase in phosphate fertilizer prices, the results of this study demonstrated the great potential of cow bone char usage which is a promising way to improve phosphorus availability in P-poor soil as well as being a clean alternative and renewable source of phosphate fertilizer. Consequently, we recommend utilizing cow bone char with sulfur as slow release fertilizer with time due to their low cost and it is a safe source of phosphorus in sustainable agriculture, rather than using Na2-EDTA due to its high price.

Changes in Nutrients and Bioavailability of Potentially Toxic Metals in Mine Waste Contaminated Soils Amended with Fly Ash Enriched Vermicompost

Mine waste contaminated soils are classified as degraded soils with poor conditions such as low soil pH, low organic matter and high metal concentrations. This study evaluated the potential of fly ash enriched vermicompost in improving poor soil conditions in mine waste affected soils. The soils were amended with the vermicompost to supply 0, 10, 20, 40 and 80 mg of phosphorus per kg and incubated for 8 weeks. The soil pH increased from the original acidic range of 3.7–5.3 to 6.8–7.6. Available P significantly improved (P < 0.001) to yield the target P levels; however, at the end of incubation period, 80 mg-P/kg treatment had lower Olsen P relative to the 40 mg-P/kg treatment. Nitrogen mineralisation was enhanced with addition of the vermicompost as reflected by an average increase of 51% in NO2/NO3−-N while NH4+-N decreased over time. The Mn, Zn and Pb solubility was reduced with addition of the vermicompost, with 20 mg-P/kg resulting in the most reduced solubility. However, concentrations at 20 mg-P/kg treatment were generally not different to 40 mg-P/kg. Solubility of Cu significantly increased in proportion to increase in amendment rate but did not exceed maximum permissible limits. Solubility of Cd and Cr also increased during the incubation study; however, this could not be attributed to the different vermicompost treatments but the soil properties. Therefore, in conclusion, application of fly ash enriched vermicompost at 40 mg-P/kg was found to be optimum for a balanced supply of essential nutrients and reduced metal solubility.

Evaluation of the efficacy of Regenamel in the treatment of white spot lesions: an in vitro study

ABSTRACT:Objective: The aim of this study was to evaluate the efficacy of REGENAMEL® on white spot lesions (WSLs)in terms of the extent of color change and the degree of mineralization.Materials and methods: Artificial white spot lesions were induced in 40 extracted human premolars, divided into a test and a control groups. REGENAMEL® was applied to the test group according to manufacturer's instructions, while the control group received no treatment. Both groups were incubated in remineralizing solution for 90 days at 37 °C. Specimens were evaluated using VITA Easyshade advance spectrophotometer at baseline (E0), after WSLs induction (E1) and 90 days following treatment (E2).DIAGNOdent evaluation was done After WSLs induction (D1) and at the end of incubation period (D2). Results: The Data was collected and statistical analyses were done using Statistical Package for Social Sciences (SPSS).No significant difference between groups was found after formation of WSLs ΔE (T0 - T1). Meanwhile significant difference was present between the two groups when comparing the color change after 90 days (T2-T1). ΔE values were 8.2 ± 4.81 and 1.92 ± 1.21 for the test and control groups respectively. Despite the final outcome showed marked improvement when compared to the baseline readings (T2-T0) 4.94 ± 3.66, the final color of the lesions was still not matching the baseline color. For the DIAGNOdent readings, at T1 the mean value for the test group was 15.55 ± 3.81 while that of the control group was 14.95 ± 2.16. At T2, for the test group, all specimens showed significantly decreased fluorescence values towards the values of sound dental tissues with mean value of 9.9 ± 1.94. The fluorescence values for the control group at T2 showed minimal change with mean value of 13.65 ± 2.03. Conclusion: REGENAMEL® is effective in improving the color of WSLs and remineralization of demineralized enamel surface.

N- Mineralization of Organic Residues in Flooded and Aerated Saline Soils under Different Temperature

Serious of incubation studies were conducted at Department of soil Science and Water Resources, College of Agriculture, university of Basrah to study the effect of temperature incubation and soil salinity levels (3, 6, 12 and 24) dS.m-1 on N mineralization of cow manure and alfalfa residue under aerobic and flooded conditions. Fifteen gram of air dry soil with salinity levels of 3, 6, 12 and 24 dS.m-1 treated with 5% of cow manure or alfalfa residue were incubated at 10, 20 or 30 ?C for 28 days. Moisture level of incubated soil was kept at either field capacity or flooded condition. NH4+ -N and NO3--N concentration of incubated samples were determined at the end of incubation period. Results showed that organic residues added to soils of all salinity levels increased NH4+ -N and NO3- - N. Concentrations of both ions were higher in alfalfa residue treatment than those of cow manure at all treatments. Highest concentrations of NH3+ -N and NO3-- N ions in all treatments obtained at samples incubated at 30 ?C and E.C. of 3 dS.m-1. Organic N mineralization under F.C. was higher than under logged water for all treatments.

The responses of soil organic carbon mineralization and microbial communities to fresh and aged biochar soil amendments

AbstractWhile biochar soil amendment has been widely proposed as a soil organic carbon (SOC) sequestration strategy to mitigate detrimental climate changes in global agriculture, the SOC sequestration was still not clearly understood for the different effects of fresh and aged biochar on SOC mineralization. In the present study of a two‐factorial experiment, topsoil samples from a rice paddy were laboratory‐incubated with and without fresh or aged biochar pyrolyzed of wheat residue and with and without crop residue‐derived dissolved organic matter (CRM) for monitoring soil organic matter decomposition under controlled conditions. The six treatments included soil with no biochar, with fresh biochar and with aged biochar treated with CRM, respectively. For fresh biochar treatment, the topsoil of a same rice paddy was amended with wheat biochar directly from a pyrolysis wheat straw, the soil with aged biochar was collected from the same soil 6 years following a single amendment of same biochar. Total CO2 emission from the soil was monitored over a 64 day time span of laboratory incubation, while microbial biomass carbon and phospholipid fatty acid (PLFA) were determined at the end of incubation period. Without CRM, total organic carbon mineralization was significantly decreased by 38.8% with aged biochar but increased by 28.9% with fresh biochar, compared to no biochar. With CRM, however, the significantly highest net carbon mineralization occurred in the soil without biochar compared to the biochar‐amended soil. Compared to aged biochar, fresh biochar addition significantly increased the total PLFA concentration by 20.3%–33.8% and altered the microbial community structure by increasing 17:1ω8c (Gram‐negative bacteria) and i17:0 (Gram‐positive bacteria) mole percentages and by decreasing the ratio of fungi/bacteria. Furthermore, biochar amendment significantly lowered the metabolic quotient of SOC decomposition, thereby becoming greater with aged biochar than with fresh biochar. The finding here suggests that biochar amendment could improve carbon utilization efficiency by soil microbial community and SOC sequestration potential in paddy soil can be enhanced by the presence of biochar in soil over the long run.

Perubahan Sifat Kimia dan Pola Pelepasan Amonium dan Nitrat pada Ultisol Darmaga yang Diberi Pupuk Pelet Berbahan Dasar Lumpur Kolam Ikan

Pupuk pelet berbahan dasar lumpur kolam ikan yang diperkaya dengan air kolam ikan dan pupuk kandang kambing dibuat untuk mengurangi kontaminasi nitrat di badan-badan air. Tujuan dari penelitian ini adalah untuk mengevaluasi perubahan beberapa sifat kimia tanah dan pola pelepasan nitrogen (N)-amonium (N-NH4+) dan N-nitrat (N-NO3-) pada Ultisol Darmaga yang diberi pupuk pelet. Dosis pupuk pelet yang diberikan ke dalam tanah adalah 6.10 g pelet/300 g tanah atau setara dengan 40.8 ton pellet ha-1. Dosis pupuk pelet yang diberikan didasarkan pada dosis pupuk N tanaman jagung manis yaitu sebesar 200 kg N ha-1. Pot-pot percobaan tersebut diinkubasi selama 1 minggu, 2 minggu, 3 minggu, 4 minggu, 5 minggu, 6 minggu, 7 minggu, 8 minggu 10 minggu, dan 15 minggu pada kondisi kapasitas lapang. Analisis tanah dilakukan pada setiap akhir masa inkubasi. Hasil penelitian menunjukkan bahwa aplikasi pupuk pelet meningkatkan pH tanah, karbon organik, kapasitas tukar kation, basa-basa dapat dipertukarkan, N-NH4+ and N-NO3- dan N-tersedia. Untuk pola pelepasan N-NH4+, dan N-NO3-, pada minggu 1 sampai minggu 7, N-NH4+ adalah bentuk N tersedia yang dominan akan tetapi menurun setelah itu. Penurunan N-NH4+ diikuti oleh kenaikan N-NO3-. Pada minggu 8 sampai minggu 15, N-NO3- adalah bentuk N tersedia yang paling dominan. Hasil penelitian merekomendasikan bahwa pupuk pelet berbahan dasar lumpur kolam ikan memperbaiki sifat tanah dan menyediakan N dalam bentuk N-NH4+ and N-NO3-.

Chemical composition and allelopathic effect of Origanum onites L. essential oil

In this study, chemical composition and allelopathic effect of essential oil obtained from ground parts (shoots+leaves+flowers) of Origanum onites L. plant on seed germination and seedling growth of different plant species were investigated. Essential oil was obtained with the use of the hydro-distillation method from O. onites plant collected from Mersin province. It was identified 24 different compounds by GC/MS analysis in O. onites essential oil, while the main compounds were determined as carvacrol (59.87%), γ-terpinene (17.08%) and β-cymene (8.83%). The allelopathic effect of the essential oil, two layers of filter paper were placed bottom of 9 cm diameter disposable Petri dishes then seeds of Amaranthus retroflexus L., Triticum aestivum L. and Lepidium sativum L. were homogeneously distributed on filter paper. Filter papers were thoroughly moistened using distilled water. The filter paper was glued to the center of the lid of each Petri dish. The different concentrations (0, 0.5, 1, 1.5, 5, 15 μl/Petri dishes) of the essential oil were applied to the filter paper pieces. Then lid of each Petri dish was closed and sealed with Parafilm. Petri dishes were incubation at 12 h dark-12 h light periods with an average temperature of 24±1 oC for 1-4 weeks. At the end of incubation period, germination rates, root and shoot lengths of the test plants were determined. The 15 μl/Petri concentration of O. onites essential oil were completely inhibited seed germination, root and shoot growth of A. retroflexus L., T. aestivum L. and L. sativum L. plants. A. retroflexus L. was found to be more sensitive to essential oil. The results show that O. onites essential oil has potential to be used in the control of A. retroflexus L., which has high allelopathic effect on seed germination and seedling development of L. sativum L., T. aestivum L., A. retroflexus L.

Combination of inductive effect of lipopolysaccharide and in situ mechanical conditioning for forming an autologous vascular graft in vivo

Autologous vascular grafts have the advantages of better biocompatibility and prognosis. However, previous studies that implanted bare polymer tubes in animals to grow autologous tubular tissues were limited by their poor yield rates and stability. To enhance the yield rate of the tubular tissue, we employed a design with the addition of overlaid autologous whole blood scaffold containing lipopolysaccharides (LPS). Furthermore, we applied in vivo dynamic mechanical stimuli through cyclically inflatable silicone tube to improve the mechanical properties of the harvested tissues. The effectiveness of the modification was examined by implanting the tubes in the peritoneal cavity of rats. A group without mechanical stimuli served as the controls. After 24 days of culture including 16 days of cyclic mechanical stimuli, we harvested the tubular tissue forming on the silicone tube for analysis or further autologous interposition vascular grafting. In comparison with those without cyclic dynamic stimuli, tubular tissues with this treatment during in vivo culture had stronger mechanical properties, better smooth muscle differentiation, and more collagen and elastin expression by the end of incubation period in the peritoneal cavity. The grafts remained patent after 4 months of implantation and showed the presence of endothelial and smooth muscle cells. This model shows a new prospect for vascular tissue engineering.

Soil lead immobilization by biochars in short-term laboratory incubation studies

Exchangeable lead (Pb) extracted by ammonium acetate from three independent incubation studies was assessed to understand the influence of feedstock, pyrolysis temperatures, and production conditions on Pb immobilization capacities of different biochars. Vegetable waste biochar, pine cone, wood bark, cocopeat, red pepper stalk, and palm kernel shell were used as feedstocks (food supply and agricultural wastes) to produce biochars at 200–650 °C with and without N2/CO2. Biochars were applied at 5 and 2.5% (w w−1) to a Pb contaminated (i.e., 1445 mg kg−1) agricultural soil collected near an old mine. Lead immobilization in biochar treated soils at the end of incubation period was normalized per gram of biochar applied. Biochar produced from vegetable waste at 500 °C showed the highest Pb immobilization (87%) and highest total exchangeable cations (13.5 cmol(+) kg−1) at the end of the 45 d incubation period. However, on the basis of Pb immobilization per gram of biochar, red pepper stalk biochar produced in CO2 at 650 °C was the best in Pb immobilization (0.09 mg kg−1 g−1 biochar) compared to the other biochars. The enhanced ability to immobilize Pb by biochar produced in CO2 could be due to the presence of siloxanes (SiOSi) on biochar surface. Pearson correlation analysis revealed that alkaline pH, ash%, and N% of biochars influence in Pb immobilization and exchangeable cation availability in soil. Biochar production atmosphere considerably change its properties that influence Pb immobilization. Further studies are needed on the modification of properties and Pb immobilization by biochars produced from various feedstocks in CO2.

Effects of Moisture Level on Nitrogen Availability in Tropical Peat Soil Cultivated with Oil Palm (Elaeis guineensis Jacq.)

Nitrogen release from soil is controlled by the soil moisture. Soil incubation was conducted to evaluate the effect of different moisture condition (75 %, 100 % and 150 %) on water holding capacity and fluctuating conditions between (150 % and 100 % water holding capacity) after application of urea and without urea addition. Ammonium and nitrate released were measured periodically over 70 days of incubation. Net mineralization and nitrification were measured at the end of the incubation period. Potential nitrification rate (PNR) was measured at the start and the end of incubation period. The results showed that the dynamics of NO 3 - did not show significant change with increased soil moisture without addition of urea. This results indicated nitrification in peat soil needed reactive N supply (urea) regardless of soil moisture conditions. Addition of urea increased the PNR ranging from 27.91 to 55.10 % compared to without urea. Fluctuating moisture condition with urea addition increased PNR by 21.82 % compared with a waterlogged condition. However, increasing soil moisture condition resulted in lower nitrate and PNR which reflect that soil moisture controlled the magnitude of PNR when urea was added.

Antibacterial Activity of Three Tooth-Colored Restorative Materials against Streptococcus mutans : An in Vitro Study

Background: Antibacterial activity of restorative materials had an important role in preventingcaries recurrence.Aim of the study: to evaluate the antibacterial effect of three tooth-colored restorative materials.Materials and Methods: Three commercially available tooth-colored restorative materials,GC Fuji (Group I), Riva self-cure (Group II) and Versa Comp (Group III) were evaluated. The testsamples of restorative materials were manipulated in accordance with manufacturer’s instructions.Eppendorf tubes were filled with constant measured amount of the three tested restorative materials;a conical cavity was created in the center of each material after curing. Bacterial suspension wasprepared from fresh overnight growth of Streptococcus mutans on blood agar. 50 μL of bacterialsuspension was placed in the conical cavity and around the restorative material inside eacheppendorf tube and then were incubated. At the end of incubation period, eppendorf tubes wereremoved from candle jar and viable bacterial count was estimated.Results: It has been found that at day1, day 2 as well as day 3, there was decrease in bacterialcount but, there was no statistically significant difference between the three groups. On studyingeach group separately, group I there was a statistically significant decrease in bacterial count at day2 and group II and III showed statistically significant decrease from day 2 to day 3.Conclusions: Fuji LC was more effective against Streptococcus mutans, than Riva self-cureand Versa comp, but with no significant difference.

Response of soil alkaline phosphatase to biochar amendments: Changes in kinetic and thermodynamic characteristics

Biochar addition to soil often increases the activity of alkaline phosphatase (ALP) involved in phosphorus (P) cycling, but the underlying mechanisms of its effect is poorly understood. This study investigated the response of kinetic parameters including maximal velocity (Vmax) and Michaelis–Menten constant (Km), and thermodynamic parameters including activation energy (Ea), enthalpy (ΔHa) and temperature coefficient (Q10) of ALP to addition of two maize biochars (400 and 600 °C) in two calcareous (Typic Haplocalcid) soils with clayey and sandy loam texture. The biochars were added to the soils at 1% (w/w) and the mixtures were incubated for 90 days under laboratory conditions (25 ± 1 °C and 70% of water holding capacity). Soils with addition of raw residue were used as positive controls and soils without biochar and raw residue were included as negative controls. The potential activity of ALP was assayed at the end of incubation period. The kinetic parameters of ALP were estimated using non-linear regression techniques and the thermodynamic characteristics were determined at different incubation temperatures (17, 27, 37, 47 and 57 °C) using the Arrhenius equation. Compared with the negative control, the addition of raw residue and biochars increased ALP activity (3.1- to 4.4-fold) after the 90-day incubation, depending upon the pyrolysis temperature and soil texture. The positive effect of biochar addition on soil ALP was greater with low than high temperature biochars and in sandy loam than clayey soils. Biochar addition increased the Km and Vmax values of ALP in the clayey soil but decreased these parameters in the sandy loam soil compared with the corresponding negative controls. Generally, application of maize raw residue and biochars increased the Ea, ΔHa and Q10 values of ALP compared with the negative controls, and the increases were similar for the two pyrolysis temperatures. Soil ALP can be strongly adsorbed by biochar particles; increasing its thermal stability and decreasing its sensitivity to elevated temperatures. In conclusion, application of maize biochar to arid-soils has a high potential to improve the ALP activity, with implications for organic P mineralization and availability. Biochar would change ALP kinetic and thermodynamic characteristics differently, depending mainly on soil texture, through the surface adsorption of this enzyme on biochar particles. These changes will be useful for modeling P mineralization and biochemical processes in biochar-amended calcareous soils.

Dynamics of soil organic carbon mineralization and C fractions in paddy soil on application of rice husk biochar

Biochar plays a pivotal role in carbon storage-fractionation-mineralization process in soil. However, uncertainty still remains about the influence of biochar on these inter-related processes that links to C cycling in soil. A three years field experiment was initiated in 2013 at ICAR-National Rice Research Institute, Cuttack, India, to study the deviation in C mineralization and C fractions caused by the application of six doses of rice husk derived biochar (RHB), ranging from 0.5 t ha−1 to 10.0 t ha−1. The results showed an increase in cumulative CO2-C emission with increasing RHB rates. However, the model-fitted mineralization rates (dC/dt) did not show significant difference between treated and control soils at the end of incubation period in a laboratory study. In addition, microbial quotient and % C from RHB utilized showed a decreasing trend with increasing rates of RHB application, establishing the carbon sequestration potential of RHB. The highest rate (10.0 t ha−1) of RHB application accumulated maximum total organic C (3.26%) and a larger share of non-labile C (63.8%) among the treatments. An increase in rice grain yield (1–24%, depending on rate of RHB application) was observed with increasing rates of RHB which further established that RHB application not only enhanced C storage but also enhanced the productivity of rice by enhancing the soil fertility.