Investigates of substrate mingling ratio and organic loading rate of KOH pretreated corn stover and pig manure in batch and semi-continuous system:Anaerobic digestion performance and microbial characteristics

The effects of substrate mingling ratio(SMR)(1:1,1:2,1:3,3:1,and 2:1)and organic loading rate(OLR)(50-90 g total solids per liter per day)on anaerobic co-digestion performance and microbial characteristics were investigated for pig manure(PM)and pretreated/untreated corn stover in batch and semicontinuous anaerobic digestion(AD)system.The results showed that SMR and pretreatment affected co-digestion performance.The maximum cumulative methane yield of 428.5 ml·g^(-1)(based on volatile solids(VS))was obtained for PCP13,which was 35.7%and 40.0%higher than that of CSU and PM.In the first 5 days,the maximum methane yield improvement rate was 378.1%for PCP13.The daily methane yield per gram VS of PCP13 was 11.4%-18.5%higher than that of PC_(U)13.Clostridium_sensu_stricto_1,DMER64,and Bacteroides and Methanosaeta,Methanobacterium,and Methanospirillum had higher relative abundance at the genus level.Therefore,SMR and OLR are important factor affecting the AD process,and OLR can affect methane production through volatile fatty acids.

Heartbeat and Respiration Rate Prediction Using Combined Photoplethysmography and Ballisto Cardiography

Owing to the recent trends in remote health monitoring,real-time appli-cations for measuring Heartbeat Rate and Respiration Rate(HARR)from video signals are growing rapidly.Photo Plethysmo Graphy(PPG)is a method that is operated by estimating the infinitesimal change in color of the human face,rigid motion of facial skin and head parts,etc.Ballisto Cardiography(BCG)is a non-surgical tool for obtaining a graphical depiction of the human body’s heartbeat by inducing repetitive movements found in the heart pulses.The resilience against motion artifacts induced by luminancefluctuation and the patient’s mobility var-iation is the major difficulty faced while processing the real-time video signals.In this research,a video-based HARR measuring framework is proposed based on combined PPG and BCG.Here,the noise from the input video signals is removed by using an Adaptive Kalmanfilter(AKF).Three different algorithms are used for estimating the HARR from the noise-free input signals.Initially,the noise-free sig-nals are subjected to Modified Adaptive Fourier Decomposition(MAFD)and then to Enhanced Hilbert vibration Decomposition(EHVD)andfinally to Improved Var-iation mode Decomposition(IVMD)for attaining three various results of HARR.The obtained values are compared with each other and found that the EHVD is showing better results when compared with all the other methods.

Contribution of Root and Microbial Respiration to Soil CO_2 Efflux and Their Environmental Controls in a Humid Temperate Grassland of Japan

Soil CO2 efflux, root mass, and root production were investigated in a humid temperate grassland of Japan over a growing season (Apr. to Sep.) of 2005 to reveal seasonal changes of soil CO2 efflux, to separate the respective contributions of root and microbial respiration to the total soil CO2 efflux, and to determine the environmental factors that control soil respiration. Minimal microbial respiration rate was estimated based on the linear regression equations between soil CO2 efflux and root mass at different experimental sites. Soil CO2 efflux, ranging from 4.99 to 16.29 μmol CO2 m-2 s-1, depended on the seasonal changes in soil temperature. The root mass at 0-10 cm soil depth was 0.82 and 1.27 kg m-2 in Apr. and Sep., respectively. The root mass at 0-10 cm soil depth comprised 60% of the total root mass at 0-50 cm soil depth. The root productivity at 0-30 cm depth varied from 8 to 180 g m-2 month-1. Microbial and root respiration rates ranged from 1.35 to 5.51 and 2.72 to 12.06 μmol CO2 m-2 s-1, respectively. The contribution of root respiration to the total soil CO2 efflux averaged 53%, ranging from 33% to 72%. The microbial respiration rate was exponentially related to soil temperature at 10 cm depth (R2 = 0.9400, P = 0.002, n = 6), and the root respiration rate was linearly related to the root production at 0-30 cm depth (R2 = 0.6561, P = 0.042, n = 6).

Human Respiration Rate Estimation Using Ultra-wideband Distributed Cognitive Radar System

It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems,which shows promise in home healthcare, rescue, and security applications. In this paper, we first present a multi-ray propagation model for UWB signal, which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces. A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment. This model enables replication of time-varying multipath profiles due to the displacement of a human chest. Subsequently,a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate. The analytical framework can serve as a basis in the planning and evaluation of future measurement programs. We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.

Effect of heat-disturbance on microbial biomass carbon and microbial respiration in Chinese fir(Cunninghamia lanceolata) forest soils

Prescribed fire has now become the usual management practice in the Chinese fir(Cunninghamia lanceolata(Lamb.) Hook.) plantation in southern China.Heat generated during fire may affect carbon(C) dynamics in soils. We investigated the microbial biomass C(MBC) and microbial respiration in two Chinese fir forest soils(one is not exposed to fire for the past 88 years, and the other is recently exposed to prescribed fire) after soil heating(100 and 200℃ ) under three moisture regimes[25, 50 and 75 % of water holding capacity(WHC)]. For both soils, significant reduction in MBC with increasing heating temperature was found. Soils without exposing to fire previously had significantly greater MBC concentration than the fire-exposed soils when heated at 100 or 200℃ . Lower soil water content resulted in higher MBC concentrations in both soils. In contrast, both soils had the highest soil microbial respiration rate at 50 % WHC. Soils without exposing to fire previously had the greatest microbial respiration rates at 200℃ , while the fire-exposed soils when heated at 100℃ had greatest microbial respiration rates. During 14-days post-heat incubation,soil MBC in both soils was greatest after heating at 200℃ and 25 % WHC. However, soil previously exposed to fire had the lowest CO2 evolution when incubated at 25 %WHC.

Relationship between oxygen concentration, respiration and filtration rate in blue mussel Mytilus edulis

The large water-pumping and particle-capturing gills of the filter-feeding blue mussel Mytilus edulis are oversized for respiratory purposes. Consequently, the oxygen uptake rate of the mussel has been suggested to be rather insensitive to decreasing oxygen concentrations in the ambient water, since the diff usion rate of oxygen from water flowing through the mussel determines oxygen uptake. We tested this hypothesis by measuring the oxygen uptake in mussels exposed to various oxygen concentrations. These concentrations were established via N2-bubbling of the water in a respiration chamber with mussels fed algal cells to stimulate fully opening of the valves. It was found that mussels exposed to oxygen concentrations decreasing from 9 to 2 mg O_2/L resulted in a slow but significant reduction in the respiration rate, while the filtration rate remained high and constant. Thus, a decrease of oxygen concentration by 78% only resulted in a 25% decrease in respiration rate. However, at oxygen concentrations below 2 mg O_2/L M. edulis responded by gradually closing its valves, resulting in a rapid decrease of filtration rate, concurrent with a rapid reduction of respiration rate. These observations indicated that M.edulis is no longer able to maintain its normal aerobic metabolism at oxygen concentration below 2 mg O 2/L, and there seems to be an energy-saving mechanism in bivalve molluscs to strongly reduce their activity when exposed to low oxygen conditions.

Soil enzymatic activities and microbial community structure with different application rates of Cd and Pb

This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd andor Pb. The soil used for experiments was collected from Beijing and classified as endoaquepts. Pots containing 500 g of the soil with different Cd andor Pb application rates were incubated for a period of 0, 2, 9, 12 weeks in a glasshouse and the soil samples were analyzed for individual enzymes, including catalase, alkaline phosphatase and dehydrogenase, and the changes of microbial community structure. Results showed that heavy metals slightly inhibited the enzymatic activities in all the samples spiked with heavy metals. The extent of inhibition increased significantly with increasing level of heavy metals, and varied with the incubation periods. The soil bacterial community structure, as determined by polymerase chain reaction-denaturing gradient gel electrophoresis techniques, was different in the contaminated samples as compared to the control. The highest community change was observed in the samples amended with high level of Cd. Positive correlations were observed among the three enzymatic activities, but negative correlations were found between the amounts of the heavy metals and the enzymatic activities.

Non-parallelism between the effect of microbial flocculants on sewerage disposal and the flocculation rate

This paper dealt with non-parallelism between the effect of microbial flocculant (MBF) on sewerage disposal and the flocculation rate, the high flocculation rate doesn’t mean the fine disposal effectiveness, and revealed the problem encountered when the exclusive parameter―flocculation rate is used to evaluate the effect of MBF on sewerage disposal. The results showed that MBF made from different carbon sources have some influence on the effectiveness of sewerage disposal; flocculation rate cannot authentically reflect the status of sewerage disposal. When the exclusive parameter―flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it would be exaggerated, especially in disposing COD-low sewerage. The authors considered that when flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it is better to take COD-removal rate into account.

Responses of soil microbial respiration to plantations depend on soil properties in subtropical China

Assessing the impact of plantation on microbial respiration(MR) is vitally important to understand the interactions between belowground metabolism and land use change. In this study, cumulative MR was determined by alkali absorption method in 1, 3, 7, 14, 21, 28, 35, 42, 49, and 56 days from the soil in a representative plantations in the subtropical region of China. The treatment of plantations contained no plant(CK), orange trees(Citrus reticulata)+Bahia grass(Paspalum notatum)(GB), orange trees(C. reticulata)+Bahia grass(P. notatum)+soybean(Giycine max(L.) Merrill)(GBH). Results showed that plantation had significant effects on microbial respiration and the responses of microbial respiration to plantation from different soil layers and topographies were different: in 0–20 cm in uphill: GB>GBH>CK; in 20–40 cm in uphill: GBH>CK>GB; in 0–20 cm in downhill: GBH>CK>GB; in 20–40 cm in downhill: GB>CK>GBH. Furthermore, plantation also altered the relationships between MR and soil properties. In CK, microbial respiration was positively correlated with NH_4^+ and soil total N, and negatively correlated with soil moisture, p H, NO_3~–, and microbial biomass carbon(MBC). In GB, microbial respiration under GB significantly negatively correlated with dissolved organic carbon(DOC). In GBH, microbial respiration under GBH was positively correlated with NH4+, MBC, total soil carbon(TC), and total soil nitrogen(TN), and negatively correlated with soil moisture(SM), p H, NO_3~–, and DOC. The underlying mechanisms could be attributed to soil heterogeneity and the effects of plantation on soil properties. Our results also showed that plantation significantly increased soil C storage, which suggested plantation is a key measure to enhance soil C sequestration and mitigate global CO2 emission, especially for the soil with low initial soil carbon content or bared soil.

Automatic detection of respiratory rate from electrocardiogram,respiration induced plethysmography and 3D acceleration signals

Respiratory monitoring is increasingly used in clinical and healthcare practices to diagnose chronic cardio-pulmonary functional diseases during various routine activities.Wearable medical devices have realized the possibilities of ubiquitous respiratory monitoring,however,relatively little attention is paid to accuracy and reliability.In previous study,a wearable respiration biofeedback system was designed.In this work,three kinds of signals were mixed to extract respiratory rate,i.e.,respiration inductive plethysmography(RIP),3D-acceleration and ECG.In-situ experiments with twelve subjects indicate that the method significantly improves the accuracy and reliability over a dynamic range of respiration rate.It is possible to derive respiration rate from three signals within mean absolute percentage error 4.37%of a reference gold standard.Similarly studies derive respiratory rate from single-lead ECG within mean absolute percentage error 17%of a reference gold standard.

Relationships between chlorophyll a, bacteria, ATP, POC and respiration rates in the Changjiang Estuary and the plume

Bacteria abundance, chlorophyll a, ATP and POC concentrations and respiration rates of microorganisms in the Changjiang Estuary and the plume were determined in July 1986. The high values of bacteria abundance occurred in the river mouth in association with suspended matter. It is assumed that bacteria were the major contributor to ATP and the main consumer of dissolved oxygen, and that the relationship between ATP and POC was present in that area. In the dilution zone (salinity; 25-30), instead of bacteria, phytoplankton was the major contributor to ATP and respiration rates, due to diatom bloom. Close relationships between Chi a and ATP, and ATP and POC were observed. Contribution of microbial carbon to POC was also estimated.

Study on Influencing Factors of Methane Production Efficiency of Microbial Electrolytic Cell with CO_(2) as Carbon Source

Reducing CO_(2) to produce methane through microbial electrolytic cell(MEC)is one of the important methods of CO_(2) resource utilization.In view of the problem of low methanogenesis rate and weak CO_(2) conversion rate in the reduction process,theflowfield environment of the cathode chamber is changed by changing the upper gas cir-culation rate and the lower liquid circulation rate of the cathode chamber to explore the impact on the reactor startup and operation and products.The results showed that under certain conditions,the CO_(2) consumption and methane production rate could be increased by changing the upper gas recirculation rate alone,but the increase effect was not obvious,but the by-product hydrogen production decreased significantly.Changing the lower liquid circulation rate alone can effectively promote the growth of biofilm,and change the properties of biofilm at the later stage of the experiment,with the peak current density increased by 16%;The methanogenic rate decreased from the peak value of 0.561 to 0.3 mmol/d,and the CO_(2) consumption did not change signifi-cantly,which indicated that CO_(2) was converted into other organic substances instead of methane.The data after coupling the upper gas circulation rate with the lower liquid circulation rate is similar to that of only changing the lower liquid circulation rate,but changing the upper gas circulation rate can alleviate the decline of methane pro-duction rate caused by the change of biofilm properties,which not only improves the current density,but also increases the methane production rate by 0.05 mmol/d in the stable period.This study can provide theoretical and technical support for the industrial application scenario offlowfield regulation intervention of microbial elec-trolytic cell methanogenesis.

复合菌剂的构建及其在沼液废水处理中的应用

通过摇瓶试验,对比研究了7株功能菌株对城市有机废弃物厌氧发酵沼液废水处理效果,并将其中4株效果较好的菌株进行复合菌剂构建,同时考察了复合菌剂最适吸附载体。结果表明:裂解亚氯酸假单胞菌(Pseudomonas chloritidismutans)对沼液氨氮(NH3-N)去除率最高,达85.1%,帚石南棒杆菌(Corynebacterium callunae)和短小芽孢杆菌(Bacillus pumilus Meyer and Gottheil)对化学需氧量(COD)的去除率较高,分别为82.7%和76.1%,总磷(TP)去除率最高的是产气克雷伯氏菌(Klebsiella aerogenes),为30.5%;4株优势菌组成的复合菌剂对沼液中氨氮的去除率达87.5%,COD去除率达86.4%,总磷的去除率达63.2%,极大地提升了处理能力;秸秆粉+玉米粉+硅藻土更适合做复合菌剂载体,有效活菌数最高,达到了2.91×108 CFU/g。

土壤水分含量对旱稻根系和土壤呼吸速率的影响

在池栽条件下比较研究了不同土壤水分含量处理(65%WHC、75%WHC、85%WHC、95%WHC和100%WHC,WHC代表田间最大持水量)对旱稻277土壤呼吸速率及根条数的影响。结果表明,土壤水分含量对旱稻土壤呼吸速率和根条数有显著影响。随着土壤水分含量的提高,土壤呼吸速率显著下降;随着旱稻生育期的推进,除100%WHC处理的土壤呼吸速率减小外,其余水分含量处理的土壤呼吸速率都呈升高趋势;随着土壤水分含量的增加,旱稻根条数逐渐降低,在分蘖前期处理间差异达到显著水平,随着生育期的推进,处理间的差异逐渐减小,且根条数与土壤呼吸速率呈显著正相关关系。土壤呼吸速率日变化在65%WHC、75%WHC和85%WHC处理下表现为逐渐增加后保持稳定,在95%WHC处理下表现为达最大值后逐渐下降,在100%WHC处理下表现为达最大值后略有下降,并一直保持在较低水平。土壤温度日变化在不同土壤水分含量下均呈现先升高再趋于平稳的变化趋势,以75%WHC水分处理下的温度最高,95%WHC和100%WHC水分处理下土壤温度较低。相关分析表明,不同水分含量处理条件下(100%WHC处理除外),土壤呼吸速率与土壤温度呈显著或极显著的二次抛物线关系,根条数与土壤呼吸速率呈显著的正相关关系。

黄土区农田土壤细菌和真菌群落对长期施氮的响应特征

【目的】细菌和真菌是调控土壤生态功能的重要因素,摸清细菌和真菌群落的变化有助于深入理解微生物在生态功能中的调节作用。【方法】黄土区渭北旱塬定位监测试验始于1984年。2022年选择其中5个不同施氮(N)量处理小区:0、45、90、135和180 kg/hm^(2)(分别记作N0、N45、N90、N135和N180),采集0—20 cm土层样品,采用16S rRNA和ITS高通量测序方法,分析细菌和真菌群落结构及其功能变化,同时测定土壤碳组分、微生物活性、根系生物量及土壤酶活性等。【结果】随着施氮量增加,土壤微生物量从113 mg/kg增加到177~234 mg/kg,微生物活性从4.92 g/(m^(2)·s)增加到5.83~7.26 g/(m^(2)·s),土壤植物根系量从1.73 t/hm^(2)增加到2.32~2.98 t/hm^(2)。施氮处理土壤细菌群落丰富度(Chao1)和多样性(Shannon)显著降低,分别下降4.0%~12.3%和1.6%~1.8%,但真菌群落丰富度和多样性无显著变化。施氮处理土壤变形菌门、芽单胞菌门、拟杆菌门相对丰度分别下降了2.4%~16.4%、2.1%~26.3%、24.1%~50.0%,细菌中座囊菌纲、伞菌纲相对丰度分别下降了29.4%~58.8%、44.4%~88.9%,而放线菌门、酸杆菌门、绿湾菌门等细菌相对丰度提高了10.4%~34.7%、37.8%~54.1%、14.3%~28.6%,子囊菌门、银耳纲等真菌的相对丰度分别提高了8.3%~73.8%、18.2%~45.5%。施氮后,土壤有机碳含量由6.50 g/kg提升到7.00~7.35 g/kg,可溶性有机碳含量由22.43 mg/kg提高到27.60~34.87 mg/kg,NO_(3)^(-)-N含量由1.38 mg/kg提高到1.78~2.25 mg/kg,C/N由8.90下降到8.64~7.74,微生物的硝化作用显著提高了14.3%~39.6%,好氧氨氧化功能提高了25.1%~48.2%,参与碳循环功能的木糖苷酶活性提高了13.5%~39.3%,纤维二糖水解酶活性提高了50.3%~126.8%。细菌丰富度和多样性变化与土壤有机碳(SOC)、可溶性有机碳、NO_(3)^(-)-N含量和C/N有关。施氮条件下细菌变形菌门丰度降低与土壤可溶性有机碳(DOC)含量升高有关,而放线菌丰度升高与SOC、DOC和NO_(3)^(-)-N含量的升高有关,但子囊菌和担子菌的丰度变化与土壤理化性质间的关系不显著。【结论】在黄土高原地区,细菌群落结构对氮肥施用的响应较真菌更为敏感。细菌群落组成的变化与土壤有机碳、可溶性有机碳和NO_(3)^(-)-N呈显著正相关,与全氮和C/N呈显著负相关。此外,氮肥施用增加了土壤中与碳循环相关的功能菌丰度,促进了木糖苷酶和纤维二糖水解酶的分泌。

长期不同施氮量下微生物残体氮对土壤氮库稳定性和玉米氮素吸收的影响

在农田生态系统中,化肥氮的施用是保障粮食高产稳产并维持土壤氮库稳定的重要管理措施,土壤微生物既是土壤氮素矿化的驱动者,也是土壤氮素固持的贡献者,在氮素保蓄和供应方面发挥着积极作用,直接影响作物的氮素吸收利用。本研究依托中国科学院栾城农业生态系统试验站小麦-玉米轮作农田14年长期不同施氮水平定位试验,选取玉米季施氮量150 kg(N)·hm^(-2)(N150)、200 kg(N)·hm^(-2)(N200)和300 kg(N)·hm^(-2)(N300)3个典型处理,通过微区施用15N标记氮肥,在收获期测定玉米产量、地上部总吸氮量和肥料氮吸收量,分析0~20 cm土层土壤全氮(TN)、微生物残体氮[MRN,包括真菌残体氮(FRN)和细菌残体氮(BRN)]、固定态铵(FN)、矿质氮(NH_4^(+)-N+NO_(3)^(-)-N,MN)和其他有机氮(ON)含量及不同氮库对^(15)N的截获,并通过多元回归分析和路径分析建立各形态氮库与玉米氮素吸收的相关关系,研究土壤“老氮”和肥料“新氮”在土壤氮库中的分配及其对作物吸收利用的影响,为研究区氮肥高效利用和地力培肥提供理论支撑。结果表明,玉米产量和氮素吸收以及土壤TN含量均以N200最高,此施氮量有利于作物高产和土壤氮库培育。N300的肥料氮吸收和残留量高于N200,表明N300的土壤氮“激发效应”强于N200,会诱导土壤“老氮”的更多矿化和损失,其土壤TN库稳定性差、更新程度较大。总氮库中,MRN占主导,N200显著高于其他处理,对TN的贡献均在50%以上,且FRN主导了MRN的累积。N200的土壤FRN∶BRN比值显著高于N150和N300,表明适宜施氮可显著提升真菌在氮素积累中的贡献,提升土壤氮库的稳定性;施氮不足(N150)或过量施氮(N300)提升了细菌在氮素积累中的贡献,不利于稳定土壤氮库。N300的MN和FN含量显著高于其他处理,表明过量施肥更多提升的是活性氮库。由此可见,适宜施氮可优化土壤氮库分配,促进更多的氮进入微生物残体氮库,显著提高土壤微生物途径对氮的固持作用,促进土壤对氮素的保蓄与供应良性运行,保障了玉米氮素吸收与产量形成,为指导华北平原农田地力培肥与氮肥减施提供了科学依据。

不同气调包装对薄荷贮藏品质的影响及薄荷保鲜呼吸速率模型的建立

为了提高薄荷采后贮藏时间和预测薄荷采后的呼吸速率,通过失重率、相对电导率、色差、感官评分、维生素C含量、总叶绿素含量和菌落总数指标的测定,从包装材料为聚乙烯包装(PE)、邻苯基苯酚复合聚乙烯包装(OPP1.8/PE3.5、OPP1.8/PE4.5、OPP2.3/PE4.5)、高密度聚乙烯包装(HDPE),O_(2)浓度为3%~7%,CO_(2)浓度为5%~15%中筛选薄荷的气调包装条件,并以O_(2)、CO_(2)和包装材料为因素开展响应面优化试验,优化薄荷采后保鲜的最优气体比例及包装材料,在此基础上研究薄荷挥发性化合物和表面真菌多样性。使用密闭空间系统法测量薄荷在最优包装材料内O_(2)和CO_(2)的比例。在此基础上,再采用渗透系统法得到模型方程,并对其进行数值模拟。运用Matlab软件对处于平衡点时的呼吸速率进行计算,利用二次多项式模型对结果进行回归分析。利用高通量测序对最优、最差和对照处理组的薄荷进行测序和分析,比较其优势菌群的占比变化。结果表明:最优气调比例及包装材料为3.5%O_(2)+9.4%CO_(2)和HDPE,该包装方式可将薄荷的保鲜期由7~9 d延长至10~12 d,可抑制薄荷贮藏期间芳樟醇等醇类物质的增加,减少D-香芹酮等酮类物质的挥发,延缓薄荷衰老,基于以上实验结果建立薄荷二次多项式呼吸速率模型,并能够更准确设计薄荷的气调包装条件,较好地抑制薄荷贮藏期间子囊菌门和霉菌门等腐败菌的生长。

葡萄枝条原位还田不同处理对其腐解及土壤性质的影响

【目的】探明枝条原位还田增施负载营养微生物菌剂、土壤调理剂、尿素对枝条腐解率及土壤性质的影响,为省时省力的枝条肥料化利用提供科学依据。【方法】以不进行葡萄枝条原位还田为对照(CK),采用田间试验方法,研究枝条原位还田不同处理〔T_(1)(不施肥)、T_(2)(尿素225 kg/hm^(2))、T_(3)(尿素225 kg/hm^(2)、负载营养微生物菌剂60 kg/hm^(2))、T_(4)(尿素225 kg/hm^(2)、负载营养微生物菌剂60 kg/hm^(2)、土壤调理剂300 kg/hm^(2))〕对枝条腐解率与土壤性质的影响。【结果】T_(4)枝条腐解率、土壤有机质、孔隙度和水分含量较CK、T_(1)、T_(2)和T_(3)分别提高12.7%~33.3%,5.52%~33.04%,3.61%~16.41%和2.40%~19.66%,土壤容重降低6.19%~16.54%。T_(4)细菌、放线菌和真菌较CK、T_(1)、T_(2)和T_(3)分别增加0.09~6.94倍、0.33~7.78倍和0.31~1.03倍。T_(4)土壤过氧化氢酶、蔗糖酶、脲酶和磷酸酶活性较CK、T_(1)、T_(2)和T_(3)分别提高0.25~5.48倍、0.04~0.65倍、0.31~1.78倍和0.12~1.60倍。各处理土壤N、P、K、Ca、Mg、Fe、Zn和B含量均为T_(4)>T_(3)>T_(2)>T_(1)>CK。【结论】葡萄枝条原位还田可提升腐解率、土壤有机质含量、孔隙度、水分含量、土壤微生物数量、酶活性与矿质元素含量,降低土壤容重,其中,以葡萄枝条原位还田时增施尿素225 kg/hm^(2)、负载营养微生物菌剂60 kg/hm^(2)、土壤调理剂300 kg/hm^(2)的效果最佳。

不同Cl^(-)浓度下SRB对抗微生物腐蚀管材性能的影响

针对油田复杂环境下管材发生腐蚀失效问题,采用SEM、EDS及XRD对试样在不同Cl^(-)浓度下(0 g/L、20 g/L、40 g/L、80 g/L和120 g/L)腐蚀后的表面形貌、腐蚀产物的成分及物相组成进行分析,通过电化学测试,研究了不同Cl^(-)浓度下SRB对抗微生物腐蚀管材性能的影响。结果发现,Cl^(-)浓度为20 g/L时最适宜SRB生长,但此时SRB对抗微生物腐蚀管材的腐蚀性最小,此后随着Cl^(-)浓度升高,生物膜减少,腐蚀速率增大;当Cl^(-)浓度分别为0 g/L、20 g/L时,在腐蚀产物中检测出FeS和Fe_(3)(PO_(4))_(2),且腐蚀均受阴极反应控制。因此,在不同Cl^(-)浓度下,SRB对抗微生物腐蚀管材性能的影响与试样表面形成的生物膜有关,随着Cl^(-)浓度的增加,SRB对抗微生物腐蚀管材腐蚀作用减小。

2023年海南省网络外卖餐饮食品微生物污染状况分析

目的:分析105批网络外卖餐饮食品微生物污染状况,为行政监管部门制定监管措施及相关标准制修订提供参考。方法:通过网络外卖App平台随机采样,按照《食品安全国家标准食品微生物学检验菌落总数测定》(GB 4789.2—2022)要求开展微生物和中心温度检测,并对检测结果不合格率进行统计学分析。结果:不同种类不合格率(χ^(2)=2.624,p> 0.05)、不同季度不合格率(χ^(2)=0.682,p> 0.05)、不同中心温度不合格率(χ^(2)=2.31,p> 0.05)均无统计学意义;菌落总数与其他微生物项目指标不合格率比较,均有极显著性差异(χ^(2)=48.451,p <0.01)。结论:本研究初步掌握了海南省网络外卖餐饮食品微生物污染的情况,为监管部门加强监管提供实验依据。