Single Factor Experiment Design Research Articles

Deep Eutectic Solvents-Based Ultrasonic-Assisted Dispersive Liquid–Liquid Microextraction for the Determination of Organophosphorus Pesticides in Honeysuckle Dew Samples

A deep eutectic solvent (DES) with the ability to change from hydrophilic to hydrophobic was designed and synthesized and applied to the determination of organophosphorus (OPP) pesticides in honeysuckle dew samples. Choline chloride, phenol, and tetrahydrofuran (THF) were used as the hydrogen bond acceptor, hydrogen bond donor, and demulsifier, respectively. Eight OPP pesticides were extracted by DES coupled with ultrasonic-assisted extraction (UA) and then chromatographed by GC-MS. DES used as an extract solvent has the advantages of high extraction efficiency, low cost, and environmental protection. Furthermore, DES is compatible with GC-MS. The single factor experiment design and Box–Behnken design (BBD) were applied to the optimization of experimental factors, including the type and composition of extraction solvent, type of demulsifier solvent, the volume of DES and THF, pH of sample solution, and ultrasonic time. Under the optimum experimental conditions, the high degree of linearity from 0.1 to 20.0 ng mL−1 (R2 ≥ 0.9989), the limits of detection from 0.014 to 0.051 ng mL−1 (S/N = 3), and the recoveries of analytes from 81.4 to 104.4% with relative standard deviation below 8.6%. In addition, the adsorption mechanism of OPPs on DES was explored by adsorption kinetic studies. These results have demonstrated that the present method has offered an effective, accurate, and sensitive methodology for OPP pesticides in honeysuckle dew samples, and this method provides a reference for the detection of pesticide residues in traditional Chinese medicine.

Mitigation of oxidative stress and inflammatory factors, along with the antibrowning and antimicrobial effects of cassia seed microbial fermentation solution.

Cassia seeds, originating from the mature seeds of leguminous cassia species, possess pharmacological effects attributed to their rich composition of various active ingredients, notably anthraquinones. While current research predominantly focuses on pharmaceutical extractions, there has been limited progress in fermentation studies. Our study aimed to enhance the content of active compounds such as anthraquinones, flavonoids, and polyphenols using microbial fermentation techniques. We specifically optimized a fermentation system through a single-factor experimental design. The antioxidant properties of the fermentation solution were validated through assays involving HaCaT cells and zebrafish. We observed effective suppression of inflammatory reactions in both RAW264.7 cells and transgenic zebrafish by the fermentation solution. Moreover, significant inhibition of tyrosinase activity and melanin production was evident in B16-F10 cells and zebrafish. Positive outcomes were also obtained in antibacterial assays and chick embryo experiments. These findings highlight the potential of cassia seed fermentation solution as a safe and eco-friendly material in food chemistry and biomedical sciences.

Passive green space exposure leading to lower aggression: The mediating role of sense of control.

Green spaces, integral to natural environments, have been extensively studied for their positive impact on mental health, yet their influence on social behavior, particularly aggression, is less explored. While prior research has predominantly emphasized the effects of actively engaging with nature, the significant role of passive nature exposure-a more common daily occurrence-has often been overlooked. We conducted two studies to explore the influence of passive green space exposure on aggression and the mediating effect of the sense of control. Study 1 (N = 240) utilized a cross-sectional survey to assess the relationship between passive green space exposure, sense of control, and aggression. Study 2 (N = 260) employed a single-factor between-subjects experimental design to further explore these relationships in a controlled environment. The results from both studies indicated that passive green space exposure is negatively related to aggression, and that this relationship is partially mediated by an increased sense of control. Specifically, passive green space exposure was found to negatively predict aggression by bolstering individuals' sense of control. These findings underscore the potential of enhancing the sense of control through environmental factors like green spaces as an effective strategy to reduce aggression. This study enriches our understanding of the broader impacts of green spaces, extending beyond mental health to include social behaviors. We discussed both the theoretical and practical implications of our findings, highlighting how urban planning and environmental design can incorporate green spaces to foster community well-being and mitigate aggressive behaviors.

Experimental study on surface roughness processed by ultrasonic surface rolling process

In order to explore the formation principle of microscopic morphology of the lower surface of USRP, USRP theoretical analysis and processing experiments are carried out. Firstly, the spatial motion trajectory of tool head by USRP is established to reveal formation principle of surface morphology. Additionally, this experiment employs a single-factor experimental design method. The influence law of process parameters and surface roughness is obtained. The results show that the workpiece speed affects the circumferential machining density of the part, and the feed speed affects the axial density of the part. Surface roughness initially decreases and subsequently increases with rising amplitudes and static pressure. It gradually rises with improvement of feed rate and rotational speed. This provides a new way to adjust the surface topography of USRP in the future.

Research on the preparation and quality control process of cattle liquid tallow

Liquid butter is a special process with unique flavor, which has strong commercial value in the deep processing of animal fat. In this paper, the preparation of liquid butter was based on centrifugal supernatant as the main raw material, and the process of preparing liquid butter by ultrasonic-assisted transesterification method was used to optimize the preparation of liquid butter by single factor and orthogonal experimental design according to the sensory, freezing point and iodine value of the product. The experimental results showed that the optimal formula of liquid butter was as follows: liquid-to-material ratio of 1:1, ultrasonic temperature of 50°C, and ultrasonic time of 50min. Using this ratio, the sensory score of liquid butter prepared from centrifugal supernatant was 87 points, the freezing point was 22.9°C, and the iodine value was 67.5g/100g. The liquid butter prepared by this process is clear and translucent, with unique flavor, and has certain nutritional and health care effects, which has certain reference value for future application in the field of deep processing of animal fat.

Effects of humic acid water-soluble fertilizer on growth and physiological characteristics of Bupleurum chinense seedlings

The effects of humic acid water-soluble fertilizer on the growth and physiological characteristics of Bupleurum chinense seedlings(Zhongchai No.1) were studied by using a single factor experiment design. When the seedling age was 60 days, the humic acid water-soluble fertilizer was diluted 1 200 times(T1), 1 500 times(T2), 1 800 times(T3), and 2 100 times(T4) for seedling treatment, respectively, and water was used as the control(CK). The effects of different treatments on growth indexes, biomass accumulation, root activity, antioxidant enzyme activity, membrane lipid peroxidation, and photosynthetic characteristics of B. chinense seedlings were analyzed after 30 days. The results showed that compared with CK, stem height, leaf number, root diameter, and root length of the B. chinense seedlings under T3 treatment were significantly increased by 36.82%, 37.03%, 42.78%, and 22.38%, respectively. Root fresh weight, leaf fresh weight, root dry weight, and leaf dry weight under T3 treatment were significantly increased by 90.36%, 98.68%, 123.84%, and 104.38%, respectively. In addition, humic acid water-soluble fertilizer also enhanced TTC reducing activity of the root of B. chinense seedlings, inhibited malonaldehyde(MDA) content, increased superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT) enzyme activities, improved chlorophyll content, and enhanced P_n, G_s, T_r, and other photosynthetic parameters. In conclusion, the application of humic acid water-soluble fertilizer diluted 1 800 times can significantly promote the growth of B. chinense seedlings, enhance root vitality, improve seedling stress resistance, and enhance photosynthesis. The results of this study can provide a theoretical basis for fertilization of B. chinense seedlings.

Finding the optimal light quality and intensity for the withering process of fuding Dabai tea and its impact on quality formation

This study investigates the pivotal role of withering in shaping the quality of white tea. We used a single-factor experimental design to optimize both the light quality and intensity during the withering process. Using gas chromatography-mass spectrometry (GC-MS), sensory evaluation, and physical and chemical analyses, we identified the ideal parameters as yellow light at an intensity of 5000 lx. Subsequently, we used non-targeted metabolomics and transcriptomics to analyze the mechanism of white tea quality formation at various stages of withering. The results showed significant changes to flavonoids during the withering process, with heightened F3′5′H (flavonoid3,5-hydroxylase) gene expression leading to increased levels of quercetin, myricetin, and luteolin. Conversely, the decreased catechin content was attributed to the decreased expression of most genes in the catechin synthesis pathway. The elevated levels of leucine, isoleucine, and GABA in free amino acids were due to a significant increase in the expression of the genes that synthesize them. Hormone and WGCNA analyses substantiated the importance of ABA, JA, and other key genes in shaping white tea quality during withering. These combined factors orchestrate the gradual formation of the distinctive characteristics of high-quality white tea.

Design and Evaluation of Ginkgolides Gastric Floating Controlled Release Tablets Based on Solid Supersaturated Self-nanoemulsifying.

Ginkgolides are receptor antagonist of platelet activating factor with great clinical prospect, but its application is limited by its low solubility, short half-life and poor alkaline environment stability. It is difficult to solve these problems with a single drug delivery system. In this study, supersaturated self-nanoemulsifying gastric floating tablets of ginkgolides were developed through the combination of solid supersaturated self-nanoemulsifying drug delivery system (solid S-SNEDDS) and gastric retentive floating drug delivery system (GFDDS) to solve these problems of ginkgolides. Solid S-SNEDDS was prepared by D-optimal mixture design, normalization method and single factor experiment. The properties of solid-S-SNEDDS were studied by TEM, PXRD, FT-IR, SEM and in vitro drug release profile. Then, the optimal formulation of stomach floating tablet was obtained through single factor experiment and center composite design, followed by the study of in vitro release, model and mechanism of release, in vitro buoyancy and kinetics of erosion and swelling. PXRD and FT-IR showed that the drug in solid S-SNEDDS existed in an amorphous manner and formed hydrogen bond with excipients. The results showed that the cumulative release of GA and GB in the optimal tablets was 96.12% and 92.57% higher than the simple tablets within 12 h. The release mechanism of the tablet was skeleton erosion and drug diffusion. In 12 h, the optimal tablets can float stably in vitro and release the drug at a constant rate, with a cumulative release of more than 80%. In summary, the combination of SNEDDS and GFDDS is a promising means to solve the problems of ginkgolides.

Set yoghurt processing with eggs as milk replacements, and improvement of texture, rheology, and microstructure by formulation design and optimisation

Eggs are suitable for the processing of set yoghurt as milk replacements, but there is no yoghurt mainly made from eggs. In the present work, production formula was designed and optimised for high-quality egg-based yoghurt processing by improving water holding capacity, aroma, texture, and taste using single factor experiment and D-optimal mixture design. Results showed that with optimised formula (whole liquid egg, 100 g; water, 180 g; sucrose, 30.89 g; diacetyl tartaric acid ester of mono(di)glycerides, 0.28 g; gelatine, 0.112 g; gellan gum, 0.14 g; and β-cyclodextrin, 0.56 g), the product showed high sensory evaluation score, fine viscosity, as well as preferable hardness and suitable fracturability. SDS-PAGE electrophoretogram indicated that the proteins in egg-based yoghurt was degraded during fermentation, which might have contributed to the improvement of gel structure and taste. Based on the SEM images, the prepared egg-based yoghurt had smoother, stronger, and more compact gel network microstructure when compared with milk-based yoghurt.

Study on microstructure of 42CrMo steel by ultrasonic surface rolling process

To explore the microstructure formation mechanism of 42CrMo steel under the strengthening of ultrasonic surface rolling process (USRP), the combination of theoretical analysis and experiment was used to conduct in-depth research on USRP. Firstly, according to contact mechanics and Hertz contact theory, the calculation model of contact stress distribution and elastoplastic strain between the rolling ball and the part during USRP is obtained. Secondly, the USRP processing test was carried out by single-factor experimental design method, and the microstructure of 42CrMo steel after USRP was analyzed by LEXT OLS5100 3D laser surface topography instrument and VEGA3 tungsten filament scanning electron microscopy, which found that with an increase in static pressure, residual stress and plastic strain gradually increase, the hardness firstly increases and then decreases, while surface roughness exhibits an initial decrease followed by an increase. The results show that USRP produces violent plastic deformation inside the material under the superposition of high-frequency impact and static pressure, at the same time, it refines the grains, so as to improve the surface performance of the part and improve its fatigue resistance.

“Human or not?” The Effect of Using Different Types of Anthropomorphic Virus on Sense of Fear and Behavior Intention: The Moderating Effect of Regulatory Focus

<p>Covid-19在短時間內透過口沫傳染迅速傳播導致了許多國家經濟大亂、恐慌並引起了人民的恐慌。病毒帶來的威脅性與高風險傳染使得人心惶惶更加恐懼且公衛宣導效果不彰。本研究欲以病毒外觀擬人化與人類外觀擬人化探討不同類型的擬人化會如何對恐懼感以及行為意圖產生影響，同時探討調節焦點對病毒擬人化之恐懼感影響。本研究採用實驗法進行，病毒擬人化 (病毒外觀擬人化vs人類外觀擬人化)之單因子實驗設計，有效樣本為191份，干擾變數調節焦點為量表檢測調節焦點類型。結果為人類外觀擬人化較容易引起高度恐懼感且對於行為意圖會有較顯著之影響。最後當自我調節焦點為促進型焦點，人類外觀擬人化會引起較高程度之恐懼感則與本研究之預期走向相反。以上結果期許可以用於未來公衛宣導以及學術研究上能有進一步之探討上有所幫助。</p> <p> </p><p>In a short period, Covid-19 rapidly spread through droplet transmission, causing economic turmoil and panic in many countries, leading to widespread fear among the public. The threatening and highly contagious nature of the virus intensified people’s anxiety, and public health campaigns showed limited effectiveness. This study aims to explore how different types of anthropomorphism, the appearance with human traits and the appearance with virus traits, impact sense of fear and behavioral intentions. Additionally, the study investigates the moderating effect of regulatory focus on the fear induced by anthropomorphizing the virus. The research adopts a single-factor experimental design (virus appearance: appearance with human traits vs. appearance with virus traits). The study includes 191 valid samples, with regulatory focus as the moderating variable, measured by a scale to identify the type of regulatory focus. Results indicate that human anthropomorphism is more likely to evoke a high level of sense of fear and significantly influence behavioral intentions. Unexpectedly, when the regulatory focus is promotion-oriented, human anthropomorphism causes a higher level of fear, contrary to the anticipated direction of the study. These findings are expected to contribute to future public health campaigns and academic research by providing insights for further exploration.</p> <p> </p>

Optimizing the Fermentation Conditions of Cudrania tricuspidata Fruit Using Bacillus amyloliquefaciens for Anti-Inflammatory Activity and GC-MS-Based Volatile Component Characteristics.

The aim of this study is to optimize the performance conditions used for maximum anti-inflammatory activity and to clarify in vitroanti-inflammatory properties of fermented C. tricuspidata fruit. Based on the single-factor experiment and Box-Behnken design, the optimized fermentation conditions of C. tricuspidata fruit for maximum anti-inflammatory activity were 3.8 d fermentation period, 8.4% (v/w) inoculation concentration, and 29.2°C fermentation temperature. Under optimal conditions, anti-inflammatory activity-based nitric oxide of fermented C. tricuspidata fruit reached 93.9%. Moreover, this study provides a theoretical basis and experimental data containing β-hexosaminidase and reactive oxygen species for the medical use and industrialization of C. tricuspidata fruit fermentation. Interestingly, the results of GC-MS analysis confirmed that fermented C. tricuspidata fruits detect volatile components different from unfermented C. tricuspidata fruits. We suggested that this volatile component may have been involved in the anti-inflammatory reaction, but scientific verification of this is needed later. Therefore, an in-depth study of volatile components detected from fermented C. tricuspidata fruits will need to be conducted later.

Young Adults' Knowledge and Perceptions of Permanent Noise-Induced Tinnitus and its Influence on Behavioural Intentions.

Young adults' music-listening behaviours may put them at risk of developing permanent hearing loss and tinnitus. This study aimed to assess knowledge of permanent tinnitus and whether this knowledge may influence listening behaviours to a greater degree than knowledge of hearing loss. A two-group (between subjects), randomised post-test only, single-factor experimental design was used to determine the effects of health message focus (permanent tinnitus vs. permanent hearing loss) on the main outcome measure of protective behavioural intention. The sample included 109 male and 287 female adults, aged 18 to 25 years, living in the United Kingdom. The young adults' existing knowledge of either permanent hearing loss or permanent tinnitus was measured, and after exposure to a health message, their perceptions and resultant behavioural intentions were assessed and compared. The pooled data were used to test a proposed model of factors influencing hearing protective behavioural intention using path analysis. Whilst 83% knew about the link with hearing loss, only 75% knew that loud music may cause permanent tinnitus. The participants viewed tinnitus as closer temporally than hearing loss, perceived themselves as equally susceptible to both, but perceived hearing loss as more severe. There was no significant difference in behavioural intention between the groups. Perceived susceptibility and severity have a positive effect on behavioural intentions. In light of these results, recommendations for future noise-damage prevention campaigns are made.

Effects of Different Proportions of Amaranthus hypochondriacus Stem and Leaf Powder Inclusions on Growth Performance, Carcass Traits, and Blood Biochemical Parameters of Broilers.

This experiment aimed to study the effects of different proportions of Amaranthus hypochondriacus stem and leaf powder (AHSL) on the growth performance, apparent nutrient digestibility, carcass traits, meat quality, and blood biochemical parameters of broilers from day 1 to day 42. The experiment utilized a single-factor experimental design, with a total of 216 one-day-old male broilers (Ross 308) randomly assigned to three dietary treatment groups (eight replicate cages of nine birds per cage). The dietary treatments included a control diet, a 3% AHSL diet and a 6% AHSL diet for days 0-21. Then, the 3% and 6% AHSL diets were changed to 5% and 10% AHSL for days 22-42. The results showed that the inclusion levels of AHSL did not affect growth performance, carcass traits, or meat quality on days 21 and 42 (p > 0.05). However, the inclusion levels of AHSL decreased the apparent nutrient digestibility (AND) of dry matter (DM) (p ˂ 0.001) and neutral detergent fiber (NDF) (p ˂ 0.001) and increased the serum concentration of phosphorus (p ˂ 0.001) on day 21. On day 42, the inclusion levels of AHSL decreased the AND of DM (p = 0.025) and NDF content (p ˂ 0.001), but increased the AND of crude protein (CP) (p = 0.004). In particular, the diet containing 10% AHSL significantly increased the serum enzyme activity of alkaline phosphatase (ALP) (p = 0.046) and the serum concentration of total protein (TP) (p ˂ 0.001) on day 42. Overall, AHSL can be used as a new and effective feed ingredient in broiler diets. It can replace part of the corn-soybean meal diet without any adverse effects, which is beneficial for conserving feed resources. Additionally, AHSL can be included at a level of up to 10% during the broiler growth period.

Study on mechanical properties and damage characteristics of cemented waste rock-tailing backfill.

Tailing and waste rock-cemented filling is an effective way to solve the problem solid waste in mines. In this paper, the effects of waste rock content and cement-sand ratio on the properties of tailing-waste rock-cemented filling materials and cemented backfill were analyzed based on the single-factor multi-level experimental design method. The results show that with the increase of waste rock content, the fluidity of the filling slurry increases first and then decreases, the bleeding rate increased gradually, and the compressive strength of the backfill increases first and then decreases. When the waste rock content is 60% and the cement-sand ratio is 1:4, the cemented backfill has higher compressive strength. With the increase of waste rock content, the interface failure area between waste rock particles and cementitious matrix under loading gradually increases, the crack extension is more complex, and the acoustic emission (AE) ringing count is higher. Microstructural analysis showed that the main hydration products in the cemented backfill were calcium silicate hydrated (C-S-H) gels, ettringite (AFt), and calcium hydroxide (Ca(OH)2). Because there is more content of hydration products, the microstructure of the cemented backfill was denser and the compressive strength was higher. Based on the results of uniaxial compression tests, the damage constitutive model of cemented backfill with different waste rock contents and cement-sand ratios was established, which could provide guidance for the design and safety production of phosphate rock filling engineering.

Редукция тревоги и депрессии через программы на гарнитуре виртуальной реальности высокой иммерсивности

<p style="text-align: justify;">The work is aimed at considering the influence of modern special training programs in virtual reality (VR) on personality anxiety in adolescence. Materials of empirical research obtained on a sample of students of 2-4 courses of Moscow and Smolensk universities are presented. Respondents aged from 19 to 24 years old participated in the study 1 (N=15) (using the training VR environment with a first-person avatar) and 2 (N=24) (using the training VR program with an anthropomorphic avatar (female) (third-person). To diagnose anxiety we used methods: Spielberger-Hanin Self-Assessment Anxiety Test, A.T. Beck Anxiety Scale. A single-factor experimental design with independent groups was used; dependent variables were different types of anxiety, independent variables were the parameters of subjects' work with the training VR-program of high immersiveness. The results show that the high level training VR environment has a significant effect on anxiety reduction. Both personal and situational anxiety, as well as the general level of anxiety, decreased. In the control samples, either anxiety decreases, but at a much lower level, or no change occurs. Psychosemantic analysis of consciousness indicates changes not only in the conscious plan (connections between connotative meanings), but also in unconscious attitudes about one's anxiety state (manifested in the triad of depression: decreased mood, ideomotor and motor retardation). In general, VR programs with avatars should be considered as effective technologies and means of changing functional personality properties, in particular anxiety.</p>

Safe Care and Medication Intake Provided by Caregivers at Home: Reality Care Study Protocol.

Providing care to patients with several conditions and simultaneously taking several medications at home is inexorably growing in developed countries. This trend increases the chances of home caregivers experiencing diverse errors related with medication or care. To determine the effectiveness of four different educational solutions compared to the natural intervention (absence of intervention) to provide a safer care at home by caregivers. Prospective, parallel, and mixed research study with two phases. Candidates: Home-based caregivers caring a person with multiple comorbid conditions or polymedication who falls into one of the three profiles of patients defined for the study (oncology, cardiovascular, or pluripathological patients). First phase: Experts first answered an online survey, and then joined together to discuss the design and plan the content of educational solutions directed to caregivers including the identification of medication and home care errors, their causes, consequences, and risk factors. Second phase: The true experiment was performed using an inter- and intrasubject single-factor experimental design (five groups: four experimental groups against the natural intervention (control), with pre- and post-intervention and follow-up measures) with a simple random assignment, to determine the most effective educational solution (n = 350 participants). The participants will be trained on the educational solutions through 360 V, VR, web-based information, or psychoeducation. A group of professionals called the "Gold Standard" will be used to set a performance threshold for the caring or medication activities. The study will be carried out in primary care centers, hospitals, and caregivers' associations in the Valencian Community, Andalusia, Madrid, and Murcia. We expect to identify critical elements of risk management at home for caregivers and to find the most effective and optimal educational solution to reduce errors at home, increasing caregivers' motivation and self-efficacy whilst the impact of gender bias in this activity is reduced. Clinical Trial NCT05885334.

Improvement of ε-Poly-l-lysine Production by Co-Culture Fermentation Strategy

ε-poly-l-lysine (ε-PL) has been routinely used as a natural and safe preservative for many years in the food industry. However, most existing production methods struggle to achieve low cost and high production simultaneously. In this work, we present a co-culture fermentation strategy to enhance ε-PL production. Specifically, we screened a strain from five different strains that could be co-cultured with Streptomyces albulus to raise the production of ε-PL. Subsequently, a single factor experiment and response surface design were used to optimize the conditions of co-culture fermentation to further improve the production of ε-PL. Moreover, the optimal fermentation process was successfully verified in a 2-L fermentor with fed batch fermentation. The production of ε-PL reached 27.07 ± 0.47 g/L by 144 h. Compared with single strain (S. albulus) fermentation, the production of ε-PL was increased by 31.47%. At the same time, the amount of bacteria increased by 19.62%, which means that the ε-PL synthesis ability of bacteria had been improved. All the obtained results showed great potential for co-culture fermentation in large-scale ε-PL production and provide a new fermentation strategy for ε-PL biosynthesis.

Optimization of nonspecific protease activity fabrication by Bacillus subtilis N30 isolated from Taiwan using different models of response surface methodology

This study aimed to identify the best growth conditions for Bacillus subtilis N30 to produce viable cell counts, pH values, and protease activity through fermentation. The research employed response surface criteria and desirability function analysis. Box-Behnken and central composite designs (BBD and CCD) were used to determine the number of processing variables and experimental runs. The results of screening single factor experimental design as maltose content (0.5–1.5% w/v), malt extract concentration (0.25%–0.75% w/v), and incubation time between 30 and 42 h were applied for coded levels (−1, 0, +1) of each independent variable correlated to steps of 0.5, 0.25, and 6, respectively. Viable cell count, pH level, and protease activity were response variables. Analysis of variance (ANOVA) revealed no significant difference when using CCD but significant linear, quadratic, and interaction influences of fermentation parameters on the response of protease activity when using BBD. Both the BBD and CCD models did not fit the viable cell count and pH. According to numerical optimization, the ideal fermentation parameters were a maltose concentration of 1.19%, a malt extract of 0.56%, and a culture time of 33 h, with a predicted protease activity yield of 5.88 U/ml. This optimum condition for growing Bacillus subtilis N30 with high protease activity will be applied in the fermentation of soy milk since it contains many short-chain peptides (2–20 amino acids), which may help prevent and manage high blood pressure for human beings.

Experimental study on extraction of organic matter from coal by liquid CO2

Liquid CO2 injection into coal seam for CH4 displacement is one of the important means to strengthen gas extraction and carbon sequestration in recent years. Liquid CO2 is a non-polar solvent, based on the principle of “similar phase solubility”, part of non-polar or weakly polar organic matter can be dissolved in liquid CO2. By controlling the key parameters of liquid CO2 in the extraction process, small molecular organic matter can be dissolved and migrated from the pore structure of coal as far as possible. In order to clarify the main factors affecting the process of liquid CO2 extraction of coal body, the experimental platform of liquid CO2 extraction of organic matter in coal body was built by ourselves, the single factor experimental design method was used to analyze the evolution law of organic matter components in the process of liquid CO2 extraction of coal body. The experimental results showed that: the macromolecular structure of coal was not significantly damaged by liquid CO2 extraction; after liquid CO2 extraction, the relative contents of aliphatic hydrocarbon and aromatic hydrocarbon are positively correlated with pressure, the dissolution of ketones, alcohols, ethers and esters has the characteristics of stage, time sequence and explosion; at the initial stage of extraction, the dissolved compounds are free in the structure of the macromolecular network. With the increase of extraction pressure and time, the small molecular compounds of hydrocarbons and non-hydrocarbons in the embedded state are dissolved.