Reduction Time Research Articles

Ultrasound and salt reduction effect on physicochemical and rheological properties of meat emulsions.

Power ultrasound and salt reduction effects on meat emulsions' physicochemical and rheological properties were determined. Therefore, meat emulsions with different NaCl concentrations (1, 1.5, 2, and 2.5%) were treated in an ultrasonic bath (40kHz, 200W, & 9.34W/cm2 ) at different times (0, 15, and 45min). Results showed that salt reduction and ultrasound time significantly (p<0.05) affected the cooking loss, water holding capacity, water activity, pH, color, hardness, viscosity, storage modulus (G'), loss modulus (G″), and phase angle δ. Meat emulsions with low salt content (1 and 1.5% NaCl) showed significantly higher values of cooking loss than standard emulsions (2.5% NaCl), while ultrasound duration of 15min reduced the cooking loss (12 to 27%). Hardness, color, pH, and water activity (aw) decreased with salt reduction. Ultrasounds increased the hardness, viscosity, G', and G'' values in reduced-salt meat. The experimental data of apparent viscosity were properly fitted to the mathematical model of Ostwald-de-Waele. Ultrasound increased consistency (k) and decreased flow behavior index (n) in emulsions with 1.5 to 2.5% NaCl. Ultrasound at 15min induced gelation in emulsions with 1.5 and 2.0% NaCl (40 and 20% NaCl reduction). The formulation with 2.0% NaCl was found to be the maximum concentration that did not sacrifice meat emulsion quality. When combined with 15 min of ultrasound, this formulation yielded results comparable to the standard formulation. PRACTICAL APPLICATION: Results contribute to developing reduced-salt meat emulsions using power ultrasounds. Therefore, using ultrasounds allows for a 20% reduction in salt content while maintaining the quality of the meat emulsion.

Photocatalytic reduction of 4-nitrophenol over eco-friendly NixCuxFe2O4 without an additional reducing agent in water

Organic pollutants such as 4-nitrophenol (4-NP) pose serious environmental extortions due to their chemical stability for which efficient catalytic materials are indispensable in treating them. In this regard, the present work involves the synthesis of two different types of ferrites (NiFe2O4, and CuFe2O4), and a combination of NixCuxFe2O4 with various ratios that systemically work as efficient photocatalysts without any additional reducing agents is reported. The structural, and morphological properties of NiFe2O4, CuFe2O4, and NiCuFe2O4 were characterized by XRD, FT-IR, SEM, and HRTEM techniques. Then, the catalytic role of individual ferrite catalysts was evaluated towards catalytic reduction of 4-NP under visible light. The progress dye reduction was examined via UV–vis spectrophotometry. The effect of various concentrations, and reduction time were investigated. The kinetic rate constants determined for NiFe2O4, CuFe2O4, and NixCuxFe2O4 revealed that Ni and Cu in bimetallic ferrites promoted the reduction reaction under visible light. The results demonstrated that the photo-reduction efficiency of the Ni0.7Cu0.3Fe2O4 catalyst over 4-NP (conc. 10 ppm) to 4-AP was determined as 82 % under 120 miniutes with good recyclability up to six cycles. The mechanism of photocatalytic reduction of ferrites without the use of a reducing agent was studied. Such facile and productive ferrite materials could be employed as efficient photocatalysts for the reduction of toxic organic contaminants in environmental treatment.

Optimizing Energy Consumption in Smart Grids Using Demand Response Techniques

Smart grids have developed as a potentially game-changing strategy for controlling the demand and supply of energy. Unfortunately, peak demand is a significant source of grid instability and rising energy prices, making it one of the most critical difficulties in smart grids. During times of high energy demand on the grid, demand response (DR) strategies incentivize consumers to change how they use energy. This study’s overarching goal is to learn how DR methods may be used to help smart grids make better use of their energy resources. The primary research is to develop a smart DR system that can predict times of high energy demand and proactively alter usage to reduce such periods. Machine learning strategies are utilized in the proposed system to estimate peak demand via past data, weather predictions, and other variables. The system will then alter energy use based on real-time data from smart meters along with other sensing devices to meet the projected demand. The simulation model will include several scenarios for testing the DR system’s flexibility, including a range of weather conditions, load profiles, and grid topologies. Several indicators, including peak demand reduction (80.04%), energy savings (38.09%), environmental consequences, and reaction time (&lt;0.4 seconds), are used to evaluate the model’s performance. The output of the method excelled all of the other current methods that were taken into account. The system’s rapid response time and its positive environmental impact further highlight its potential in managing smart grid resources effectively.

Inactivation Kinetics of Foodborne Pathogens in Carrot Juice by High-Pressure Processing.

In this study, Salmonella Typhimurium, Escherichia coli, and Listeria monocytogenes were separately inoculated in sterilized carrot juice and subjected to various types of high-pressure processing (HPP) at 200-600 MPa for 0.1-15 min to observe the effects of HPP on the inactivation kinetics of foodborne pathogens in carrot juice. The first-order model fits the destruction kinetics of high pressure on foodborne pathogens during the pressure hold period. An increase in pressure from 200 to 600 MPa decreased the decimal reduction time (D values) of S. Typhimurium, E. coli, and L. monocytogenes. Under pressure ≥ 400 MPa, the D values of E. coli were significantly higher than those of S. Typhimurium and L. monocytogenes, indicating that E. coli had greater resistance to high pressures than the others. The Zp values (the pressure range that causes the D values to change by 90%) of E. coli, S. Typhimurium, and L. monocytogenes were 195, 175, and 170 MPa, respectively. These results indicated that L. monocytogenes and E. coli were the most and least sensitive, respectively, to pressure changes. Additionally, the three bacteria were separately inoculated into thermal-sterilized carrot juice and subjected to 200-600 MPa HPP for 3 min. The treated carrot juices were stored at 4 °C for 27 d. Following S. Typhimurium and E. coli inoculation, the bacterial counts of the control and 200 MPa treatments remained the same during the storage duration. However, they decreased for the 300 and 400 MPa treatment groups with increasing storage duration. During the storage period, no bacterial growth was observed in the 500 and 600 MPa treatments. However, the bacterial number for the control and pressure treatment groups increased with prolonged storage duration following inoculation with L. monocytogenes. Therefore, following HPP, residual L. monocytogenes continued growing stably at low temperatures. Overall, HPP could inhibit and delay the growth of S. Typhimurium and E. coli in carrot juice during cold storage, but it was ineffective at inhibiting the growth of L. monocytogenes. There was a risk of foodborne illness despite the low-temperature storage of juice. The innovation of this preliminary study is to find the impact of high pressure on the inactivate kinetics of three food pathogens in carrot juice and its practical application in simulated contaminated juice.

Employing a magnetic metal organic framework-derived graphene oxide enhanced with incorporated copper: An exceptional catalyst for the selective reduction of organic dyes and nitro compounds

Magnetic metal-organic frameworks have emerged as versatile materials with wide-ranging applications in various scientific fields, particularly catalysis. These materials possess remarkable properties such as magnetic saturation, stability, and biocompatibility, making them highly desirable for numerous applications. In this study, our objective was to design and synthesize a new magnetic metal-organic framework-based catalyst containing copper species. To achieve this, a multi-step approach was employed. Firstly, Fe3O4 nanoparticles were functionalized with silica to prevent aggregation. Subsequently, individual functionalization with glutamic acid and modification with graphene oxide containing copper were carried out. This sequential process resulted in the formation of a unique catalyst, Fe@Si-GA-GO-Cu MOF. To gain insights into the structural and physicochemical properties of the resulting magnetic catalyst, comprehensive characterization techniques were employed. Furthermore, the catalytic behavior and kinetic study of Fe@Si-GA-GO-Cu MOF in the reduction of nitroarenes, methylene blue and Congo red were successfully investigated that demonstrated remarkable efficiency in reducing 4-nitrophenol within a brief timeframe of 9 min. Additionally, it exhibited impressive performance in the reduction of methylene blue and Congo red, achieving reduction times of 57 s and 11 min, respectively. Furthermore, the catalyst highlighted remarkable reusability, retaining its catalytic activity for at least 9 cycles without any pre-activation or significant loss of activity or leaching of copper. The Fe@Si-GA-GO-Cu MOF exhibited several notable advantages such as, smooth and clean reaction conditions at room temperature. This innovative approach not only addresses environmental concerns by preventing pollution from industrial effluents but also significantly accelerates reaction times through the utilization of cost-effective and economical catalysts.

Tranexamic acid in bleeding reduction and operative time of nasal surgeries: systematic review and meta-analysis.

Our study goal is to review the efficacy of tranexamic acid in reducing blood loss and operative time in nasal surgeries. We included randomized clinical trials using oral or intravenous tranexamic acid, excluded non-randomized studies, topic administration, coagulopathy, and using other drugs interfering in the coagulation cascade. Online databases, National Library of Medicine (MEDLINE-PubMED), Latin American and Caribbean Literature on Health Sciences (Lilacs), Cochrane Library, Embase and Google Scholar were used to perform the search. The review was registered in PROSPERO by no CRD42022310977. Two authors, independently, selected the articles meeting the inclusion criteria. They extracted the data and used RevMan 5 software to perform the meta-analysis. Our search resulted in 16 RCTs that were included in the meta-analysis totalizing 1108 patients. Studies were evaluated resulting in a low risk of bias for the five domains. The use of tranexamic acid resulted in significant reduction in duration of surgery (DOS) and intraoperative blood loss (IBL) had significant reduction. The level of evidence according to GRADE System was high in all studies and variables. Tranexamic acid has an important role in reducing intraoperative blood loss and duration of surgery. Our study has some limitations due to the low number of RCTs available in the literature.

Pyrometallurgical recovery of zinc and valuable metals from hazardous blast furnace dust via self-reduction roasting: Phase transformations and morphological evolution

Blast furnace dust (Zn–Fe dust) containing high heavy metal contents is a hazardous waste, and it is derived from the gravity dust removal system and bag dust removal system of a blast furnace. This study elucidated the underlying reasons for the poor separation of Zn and Fe and recommended conditions for the carbothermic reduction roasting process. The results indicated that the poor efficiencies for Zn and Fe separation from Zn–Fe dust were caused by the formation and gradient reduction of wustite (FeyZn1-yO). A higher reduction temperature, longer reduction time and basicity created an advantageous environment for reduction of the wustite intermediate phase and enabled synergistic catalytic reduction of the wustite phase (FeyZn1-yO and FeyCa1-yO). The formation and reduction of the wustite phase (FeyZn1-yO and FeyCa1-yO) are crucial steps in reduction roasting of olivine (ZnyFe2-ySiO4) and ZnxFe3−xO4 with a spinel crystal structure. After adjusting the experimental parameters, the efficiencies for recovery of Zn and Fe from the Zn–Fe dust reached 95.12 % and 96.55 %, respectively.

Preoperative virtual reduction method for pelvic fractures based on statistical shape models and partial surface data

Virtual reduction is crucial for successful and accurate reduction of pelvic fractures. Various methods have been proposed in this regard. However, not all of them are applicable to every pelvic fracture. Among these methods, the efficiency and accuracy of the method based on statistical shape models in clinical applications require further improvement. This study proposes a virtual reduction method for pelvic fractures that uses statistical shape models and partial surface data of a broken pelvis. Simulated fracture and clinical case experiments were conducted to validate the accuracy and effectiveness of the proposed method. The simulated fracture experiments yielded an average error of 1.57 ± 0.39 mm and a maximum error of 12.82 ± 3.54 mm. The virtual reduction procedure takes approximately 40 s. Based on three clinical case experiments, the proposed method achieves an acceptable level of accuracy compared with manual reduction by a surgeon. The proposed method offers the advantages of shorter virtual reduction times and satisfactory reduction accuracy. In the future, it will be integrated into the preoperative planning system for pelvic fracture reduction, thereby improving patient outcomes.

Premature drug reduction after subthalamic nucleus deep brain stimulation leading to worse depression in patients with Parkinson's disease

BackgroundReduction of medication in Parkinson's disease (PD) following subthalamic nucleus deep brain stimulation (STN-DBS) has been recognized, but the optimal timing for medication adjustments remains unclear, posing challenges in postoperative patient management.ObjectiveThis study aimed to provide evidence for the timing of medication reduction post-DBS using propensity score matching (PSM).MethodsIn this study, initial programming and observation sessions were conducted over 1 week for patients 4–6 weeks postoperatively. Patients were subsequently categorized into medication reduction or non-reduction groups based on their dyskinesia evaluation using the 4.2-item score from the MDS-UPDRS-IV. PSM was employed to maintain baseline comparability. Short-term motor and neuropsychiatric symptom assessments for both groups were conducted 3–6 months postoperatively.ResultsA total of 123 PD patients were included. Baseline balance in motor and non-motor scores was achieved between the two groups based on PSM. Short-term efficacy revealed a significant reduction in depression scores within the non-reduction group compared to baseline (P &amp;lt; 0.001) and a significant reduction compared to the reduction group (P = 0.037). No significant differences were observed in UPDRS-III and HAMA scores between the two groups. Within-group analysis showed improvements in motor symptoms, depression, anxiety, and subdomains in the non-reduction group, while the reduction group exhibited improvements only in motor symptoms.ConclusionThis study provides evidence for the timing of medication reduction following DBS. Our findings suggest that early maintenance of medication stability is more favorable for improving neuropsychiatric symptoms.

Improved GNSS Ambiguity Fast Estimation Reduction Algorithm.

The fast and accurate solution of integer ambiguity is the key to achieve GNSS high-precision positioning. Based on the lattice theory of high-dimensional ambiguity solving, the reduction time consumption is much larger than the search time consumption, and it is especially important to improve the efficiency of the lattice basis reduction algorithm. The Householder QR decomposition with minimal column pivoting is utilized to pre-sort the basis vectors and reduce the number of basis vector exchanges during the reduction process by partial size reduction and relaxing the basis vector exchange condition to improve the reduction efficiency of the LLL algorithm. The improved algorithm is validated using simulated and measured data, respectively, and the performance advantages and disadvantages of the improved algorithm are evaluated from the perspectives of the extent of reduction basis orthogonality and the quality of reduction basis size reduction. The results show that the improved LLL algorithm can significantly reduce the number of basis vector exchanges and the reduction time consumption. The HSLLL and PSLLL algorithms with the Siegel condition as the basis vector exchange condition have a better reduction effect, but are slightly less stable. The PLLLR algorithm significantly improves the search ambiguity resolution efficiency, which is conducive to the rapid realization of ambiguity resolution.

Microstructure Evolution and Phase Transformation of Iron Produced from the Sustainable Carbothermic Reduction Process of High-Pressure Acid Leaching Residue.

This paper describes the microstructure evolution and phase transformation of residue from the lateritic nickel ore high-pressure acid leaching (HPAL) during carbothermic reduction using palm kernel shell (PKS) charcoal as a reductant. The study consisted of thermodynamic calculations combined with analysis of reduction experiments. The thermodynamic assessment predicted that the main phases formed during the reduction process were γ-Fe metal, liquid metal, slag, and spinel, with abundance of reducing gas (CO and H2) at the temperature range of 750-1500 °C. The experimental study shows that the resulting product upon cooling was sponge iron or direct reduced iron when HPAL residue-PKS charcoal composites were reacted up to 1400 °C for 45 min. The sponge iron had an average apparent density of 5.8 ± 0.1 g/cm3 and a 90.8 ± 0.4% metallization degree. The microstructure analysis revealed that as the reduction time was increased, small iron nuggets began forming on the surface of the reduced product. By addition of Na2CO3, the separation of iron nuggets from slag appeared to be improved, hence enhancing the overall reduction process. Furthermore, iron nuggets' highest apparent density and metallization degree were obtained at 7 ± 0.1 g/cm3 and 98 ± 0.5%, respectively, when adding Na2CO3 of 6 wt %. The phase and microstructure analyses also revealed that the iron nuggets comprised coarse pearlite, eutectic cementite, ledeburite, and sulfides. Thus, this study offers alternative sustainable process conditions for simultaneously handling the HPAL residue using PKS waste to produce metallic iron.

ANALISIS KARAKTERISITIK KOMPOSIT SERBUK KAYU, SERABUT KELAPA DAN CANGKANG KERANG PADA REM TROMOL SEPEDA MOTOR LISTRIK

The background of this study was taken to utilize the residual waste produced by wood powder, coconut fiber and green shells. The purpose of this study is to find the best composite variation on electric motorbike brake pads made from wood powder, coconut fiber and green shells powder on bending test, the mass reduction test and braking time. The Experimentation Method used in this reserach was carried out by varying the compositon of the 3 brake pads test specimens namely SK20SKL20CK0R60, SK20SKL20CK10R50 and SK20SKL20CK20R40 then performed bending test, the mass reduction and braking time. Based on the bending test results obtained, the SK20SKL20CK0R60 test specimen has the strongest rate amounted to 186,33 N. then for the mass reduction and braking time value in this study, the test was carried out by taking the test from 3 test laps (track) and carried out 9 times the test (braking) on each lap. Based on the mass reduction test and braking time, the SK20SKL20CK0R60 specimen has the closest indication to standard brake lining value of 0.0066 grams.

Enhanced Photocatalytic Activity of Lead‐Free Cs2TeBr6/g‐C3N4 Heterojunction Photocatalyst and Its Mechanism

AbstractIn this study, a new type of lead‐free double perovskite Cs2TeBr6 combined with metal‐free semiconductor g‐C3N4 heterojunction is constructed and used for photocatalytic CO2 reduction for the first time. The S‐scheme charge transfer mechanism between Cs2TeBr6 and g‐C3N4 is systematically verified by X‐ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) and in situ Fourier infrared spectroscopy(FT‐IR). The formation of S‐type heterojunction makes the photocatalyst have higher charge separation ability and highest redox ability. The results show that 5%‐CTB/CN heterojunction material has the best photocatalytic reduction effect on CO2 under visible light irradiation. After 3 h of illumination, the yield of CO and CH4 are 468.9 µmol g−1 and 61.31 µmol g−1, respectively. The yield of CO is 1.5 times and 32 times that of pure Cs2TeBr6 and g‐C3N4, and the yield of CH4 is doubled compared with pure Cs2TeBr6. However, g‐C3N4 almost does not produce CH4, which indicates that the construction of heterojunction helps to further improve the photocatalytic performance of the material. This study provides a new idea for the preparation of Cs2TeBr6/g‐C3N4 heterojunction and its effective interfacial charge separation.

The impact of landfill management approaches on methane emissions.

This article reports on how management approaches influence methane emissions from landfills. The project team created various landfill operational scenarios for different regions of the planet with respect to waste composition, organic waste reduction and landfill gas recovery timing. These scenarios were modelled by applying a basic gas generation model according to the United Nations Intergovernmental Panel on Climate Change (IPCC) recommendations. In general, the IPCC's recommended modelling parameters and default values were used. Based on the modelling undertaken, two options stand out as being the most effective methane mitigation measures in a wide range of conditions throughout the world: (a) early gas recovery and (b) reduction of the amount of biodegradable organic waste accepted in a landfill. It is noted that reduction of organic input to any given landfill can take many years to realize. Moreover, suitable alternative processing or disposal options for the organic waste can be unaffordable for a significant percentage of the planet's population. Although effective, organic waste reduction cannot therefore be the only landfill methane mitigation measure. Early landfill gas recovery can be very effective by applying basic technologies that can be deployed relatively quickly, and at modest cost. Policymakers and regulators from around the globe can significantly reduce adverse environmental impacts from landfill gas emissions by stimulating both the early capture and flaring and/or energy recovery of landfill gas and programmes to reduce the inflow of organic waste into landfills.

Soil erosion under forest hampers beech growth: Impacts of understory vegetation degradation by sika deer

The overpopulation of large herbivorous mammals degrades understory vegetation and hence promotes soil erosion in some northern hemisphere forests. Topsoil removal via erosion reduces soil water and nitrogen (N) content as well as exposes tree roots. However, whether topsoil removal inhibits tree growth through water and N uptake limitations has not been examined. This study aimed to measure the vertical length from exposed roots surface to the soil surface (exposed root height; ERH) under degraded forest understory vegetation and to evaluate its influence on tree growth. Specifically, we examined the relationships between ERH and beech growth and identified the timing of growth reduction based on annual tree-ring analysis at the individual scale. Furthermore, we discussed the effects of water and N limitations on beech growth reduction. We studied 12 Japanese beech trees on Mt. Sanpo, southern Kyushu Island, Japan, where understory vegetation was degraded and lost due to herbivory by Japanese sika deer from 1980 to 2003. Lower amounts of leaf production and relative growth rates of stem basal area increment (BAI) were observed in beech trees with higher ERH. Segmented regression analysis, which detects the changing time of a temporal trend (i.e., break-point), revealed that the BAI has resulted in a decreasing trend after 1997.6 ± 9.0 (yr), which coincided with the field observations on understory degradation in the study site. After the break-point of the BAI, the BAI of each study tree was negatively related to intrinsic water use efficiency, an integrated index of water limitation. These results suggest that soil erosion after the degradation of understory vegetation reduced beech growth, possibly because of the water limitations associated with root exposure. Reduced beech growth will reduce the supply of the litter layer that prevents topsoil erosion, which may enhance further soil erosion and tree growth reduction.

Use of angled-tip aspiration catheters is associated with a lower cost of thrombectomy in patients with acute ischemic stroke secondary to large and medium vessel occlusions.

Recently, the angled-tip Zoom™ aspiration catheters were introduced. The tip is designed to improve suction force for clot retrieval. We evaluated the possibility of reducing procedure costs when using angled-tip catheters and compared the safety and angiographic effectiveness of angled-tip versus straight-tip catheters. We conducted a retrospective single-center cohort study involving patients with acute ischemic stroke due to large and medium vessel occlusions. The patients were divided into two groups: the post-Zoom group, in which angled-tip aspiration catheters were used and the pre-Zoom group, in which traditional straight-tip catheters were employed. A total of 163 patients were included; 95 (58.3%) in the pre-Zoom group and 68 (41.7%) in the post-Zoom group. The groups were well-matched at entry. The post-Zoom group demonstrated a significant decrease in mean procedure cost ($9728 vs. $12,127; p = 0.002), shorter time to achieve modified thrombolysis in cerebral infarction ≥2b reperfusion (38.30 min vs. 53.26 min; p = 0.018), and shorter puncture to procedure completion time (46.42 min vs. 62.38 min; p = 0.022). Additionally, the mean procedural cost when using the ADAPT technique supported by the Zoom catheters was significantly lower than the Solumbra technique ($5754 ± $2806 vs. $13,498 ± $3244, p < 0.001). There were no differences in the rate of hemorrhage between the pre-Zoom group (17.9%) and the post-Zoom group (20.6%), p = 0.690. The study demonstrated significant benefits, including cost reduction and shorter time to achieve reperfusion in patients treated with Zoom aspiration catheters. These findings support the use of angled-tip catheters in acute ischemic stroke management.

Extracting the Synthetic Route of Pd-Based Catalysts in Methanol Steam Reforming from the Scientific Literature.

The structured material synthesis route is crucial for chemists in performing experiments and modern applications such as machine learning material design. With the exponential growth of the chemical literature in recent years, manual extraction from the published literature is time-consuming and labor-intensive. This study focuses on developing an automated method for extracting Pd-based catalyst synthesis routes from the chemical literature. First, a paragraph classification model based on regular expressions is employed to identify paragraphs that contain material synthesis processes. The identified paragraphs are verified using machine learning techniques. Second, natural language processing techniques are applied to automatically parse the material synthesis routes from the identified paragraphs, generate regularized flowcharts, and output structured data. Lastly, we utilized the structured data of the synthesis routes to train machine learning models and predict the performance of the materials. The extracted material entities include the product, preparation method, precursor, support, loading, synthesis operation, and operation condition. This method avoids extensive manual data annotation and improves the scientific literature information acquisition efficiency. The accuracy of the 11 material entities exceeds 80%, and the accuracy of the method, support, precursor, drying time, and reduction time exceeds 90%.

Kinetics analysis of direct reduction of iron ore by hydrogen in fluidized bed based on response surface methodology

The present research investigates the efficacy of fluidized bed direct reduction of hematite ore using H2 as a metallurgical technology. The study uses response surface methodology (RSM) to obtain the optimal kinetics system for fluidized H2 reduction of hematite ore. The interaction of independent parameters, including reduction time, reduction temperature, fluidizing velocity, and H2 concentration with dependent variables comprising the reduction degree are explored. The final equation for the reduction degree can be established according to RSM analysis. Additionally, for the hematite reduction using H2 in a fluidized, the study investigates the mechanisms and kinetics of isothermal reduction. The result demonstrates that the reduction degree increases with the reduction temperature, fluidizing velocity, and H2 concentration, as well as the reduction mechanisms change with reduction conditions. For instance, an increase in fluidizing velocity and H2 content promotes the transformation of the kinetics model from D3 to D3+F1 and R3+F1 mixed control, respectively. The activation energy for the fluidized H2 reduction of hematite ore to metallic iron Fe ranges from 23.76 to 54.89 kJ/mol.

Neutral effect of nitrogen addition and negative effect of precipitation reduction on the soil faunal community in a temperate forest

ABSTRACT Nitrogen deposition can promote belowground soil carbon pools, and precipitation reduction can eliminate this positive effect. Soil fauna play crucial roles in regulating the dynamics of organic matter and maintaining biodiversity in ecosystems. However, it is not clear whether belowground soil fauna have similar responses to changes after long-term nitrogen deposition and drought. We simulated nitrogen deposition by applying fertilizer, and simulated drought by excluding 30% of the ambient precipitation in a temperate forest from 2009. Our results showed that experimental precipitation reduction alone significantly changed the composition and decreased the abundance of the soil faunal community. Precipitation reduction could also promote the soil food web in a fungal-dominated pathway by decreasing trophic groups of Isotomidae abundance. In contrast, although nitrogen addition treatment increased soil available nitrogen content, it had a neutral effect on the soil faunal community. Soil faunal community showed strong temporal variations in response to both nitrogen deposition and precipitation reduction treatments. Notably, interactions between precipitation reduction, nitrogen addition, and sampling time were significant for specific trophic groups, including saprozoites and omnivores. Shannon-Weiner diversity was not sensitive to these global change factors. Our results suggest that soil water content and plant richness may, directly and indirectly, regulate the soil faunal community.

An improved MTT colorimetric method for rapid viable bacteria counting

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay has been employed in the analysis of bacterial growth. In comparison to experiments conducted on mammalian cells, the MTT bacterial assay encounters a greater number of interfering factors and obstacles that impact the accuracy of results. In this study, we have elucidated an improved MTT assay protocol and put forth an equation that establishes a correlation between colony-forming units (CFU) and the amount of formazan converted by the bacteria, drawing upon the fundamental principle of the MTT assay. This equation is represented as CFU=kF. Furthermore, we have explicated a methodology to determine the scale factor “k” by employing S. aureus and E. coli as illustrative examples. The findings indicate that S. aureus and E. coli reduce MTT by a cyclic process, from which the optimal reduction time at room temperature was determined to be approximately 30 mins. Furthermore, individual E. coli exhibits an MTT reduction capacity approximately four times greater than that of S. aureus. HPLC analysis proves to be the most accurate method for mitigating interferences during the dissolution and quantification of formazan. Additionally, this study has identified a new constraint related to the narrow linear range (0–125 μg/mL) of formazan concentration-absorbance and has presented strategies to circumvent this limitation.