Fate of degraded pollutants in waste gas biofiltration: An overview of carbon end-points

The fate of the carbon from degraded pollutants in biofiltration is not well understood. The issue of missing carbon needs to be addressed quantitatively to better understand and model biofilter performance. Elucidating the various carbon end-points in various phases should contribute to the fundamental understanding of the degradation kinetics and metabolic pathways as a function of various environmental parameters. This article reviews the implications of key environmental parameters on the carbon end-points. Various studies are evaluated reporting carbon recovery over a multitude of parameters and operational conditions with respect to the analytical measurements and reported distribution of the carbon end-points.     

Responses of community structure of amoA‐encoding archaea and ammonia‐oxidizing bacteria in ammonia biofilter with rockwool mixtures to the gradual increases in ammonium and nitrate

Aims

To investigate community shifts of amoA‐encoding archaea (AEA) and ammonia‐oxidizing bacteria (AOB) in biofilter under nitrogen accumulation process.

Methods and Results

A laboratory‐scale rockwool biofilter with an irrigated water circulation system was operated for 436 days with ammonia loading rates of 49–63 NH₃ g m^?3 day^?1. The AEA and AOB communities were investigated by denaturing gradient gel electrophoresis, sequencing and real‐time PCR analysis based on amoA genes. The results indicated that changes in abundance and community compositions occurred in a different manner between archaeal and bacterial amoA during the operation. However, both microbial community structures mainly varied when free ammonia (FA) concentrations in circulation water were increasing, which caused a temporal decline in reactor performance. Dominant amoA sequences after this transition were related to Thaumarchaeotal Group I.1b, Nitrosomonas europaea lineages and one subcluster within Nitrosospira sp. cluster 3, for archaea and bacteria, respectively.

Conclusions

The specific FA in circulation water seems to be the important factor, which relates to the AOB and AEA community shifts in the biofilter besides ammonium and pH.

Significance and Impact of the Study

One of the key factors for regulating AEA and AOB communities was proposed that is useful for optimizing biofiltration technology.     

Genotypic difference in canopy diffusive conductance measured by a new remote-sensing method and its association with the difference in rice yield potential

There have been few practical ways of measuring physiological determinants of rice yield. Rapid evaluation of yield determination traits may expedite breeding of high-yielding rice. Here, we report a new remote-sensing technique for the evaluation of canopy ecophysiological status under field conditions developed based on simultaneous measurements of sunlit and suddenly shaded canopy temperatures. This technique has the advantage of instantaneous estimation of aerodynamic resistance (r(a)) and canopy diffusive resistance (r(c) without measuring wind velocity. Canopy diffusive conductance (1 / r(c)) estimated by the remote sensing method was closely related to leaf stomatal conductance (g(s)) measured with a portable gas exchange system. This result supported the validity of this new method for quantitative estimation of canopy physiological characteristics. Significant genotypic differences were obtained in canopy-air temperature difference (Tc-Ta), r(c) and 1 / r(c) during the 2-week period preceding full heading for two years, and 1 / r(c) was highly correlated with crop growth rate (CGR), which was closely related to the final yield. These results suggest that 1 / r(c) can be an effective criterion for the selection of high-yielding rice genotypes, and the remote sensing technique proposed here can be a powerful tool for the rapid evaluation of 1 / r(c) under field conditions.     

Growth inhibition of biomass adapted to the degradation of toluene and xylenes in mixture in a batch reactor with substrates supplied by pulses

A biomass adapted to degrade toluene and xylenes in mixture was grown in a batch reactor with substrates supplied by pulses. The inhibition of biomass growth in the course of substrate degradation was investigated. The maximal biomass concentration of 7 g l^–1 was obtained using 150 l of toluene and 15 l of a mixture of xylenes in one litre of liquid medium, and the maximal biomass productivity and yield were 53 mg l^–1 h^–1 and 0.32 g_DW g _s ^–1 , respectively. Higher quantities of substrate added by pulses, that is 200 l of toluene with 20 l of xylenes and 300 l of toluene with 30 l of xylenes, caused an accumulation of metabolites. These higher quantities of substrates caused inhibition of microbial growth. Among the metabolites produced, 4-methyl catechol was found in large quantities in the culture medium and in the cells.     

Electromagnetic simulation of RF burn injuries occurring at skin-skin and skin-bore wall contact points in an MRI scanner with a birdcage coil

PurposeTo simulate radiofrequency (RF) burns that frequently occur at skin–skin and skin–bore wall contact points.MethodsRF burn injuries (thumb–thigh and elbow–bore wall contacts) that typically occur on the lateral side of the body during 1.5 T magnetic resonance imaging (MRI) scans were simulated using a computational human model. The model was shifted to investigate the influence of the position of the patient in an MRI scanner. The specific absorption rate (SAR), electric field, and temperature were mapped.ResultsRegarding the contact points located near the edge of the birdcage transmission coil, under the allowable maximum RF power exposure i.e., the average whole-body SAR at the safety limit value (2 W/kg), the 10-g-tissue-averaged SAR (SAR_10g) at those points significantly increased for both the thumb–thigh (180 W/kg) and elbow–bore wall (48 W/kg) cases. Both values significantly exceeded the highest safety limit of the partial-body SAR (10 W/kg). The electric field, the square of which is proportional to SAR, was remarkably high near the edge of the birdcage transmission coil. The peak SAR_10g for each injury case was associated with contact-point peak temperatures that reached 52 °C at approximately 1 min following RF exposure onset; a 1-min period of exposure to this temperature causes a first-degree burn.ConclusionsWe demonstrated high heat generation in RF burn injury cases in silico. The RF heating occurring on the lateral side of the body was strongly dependent on the electric field distribution, which is dominantly determined by an RF transmission coil.     

Photosynthesis and growth of Arthrospira (Spirulina) platensis (Cyanophyta) in response to solar UV radiation, with special reference to its minor variant

The minor variant of the economically important cyanobacterium, Arthrospira platensis, usually appears in commercial production ponds under solar radiation. However, how sensitive the minor variant to solar UVR and whether its occurrence relates to the solar exposures are not known. We investigated the photochemical efficiency of PSII and growth rate of D-0083 strain and its minor variant in semi-continuous cultures under PAR (400–700 nm) alone, PAR + UV-A (320–400 nm) and PAR + UV-A + UV-B (280–700 nm) of solar radiation. The effective quantum yield of D-0083 at 14:00 p.m. decreased by about 86% under PAR, 87% under PAR + UV-A and 92% under PAR + UV-A + UV-B (280–315 nm), respectively. That of the minor variant was reduced by 93% under PAR and to undetectable values in the presence of UV-A or UV-A + UV-B. Diurnal change of the yield showed constant pattern during long-term (10 days) exposures, high in the early morning and late afternoon but the lowest at noontime in both strains, with the UVR-related inhibition being always higher in the variant than D-0083. During the long-term exposures, cells of D-0083 acclimated faster to solar UV radiation and showed paralleled growth rates among the treatments with or without UVR at the end of the experiment; however, growth of the minor variant was significantly reduced by UV-A and UV-B throughout the period. Comparing to the major strain D-0083, the minor variant was more sensitive to UVR in terms of its growth, quantum yield and acclimation to solar radiation.     

Life history and production of Paranephrops zealandicus in a forest stream, with comments about the sustainable harvest of a freshwater crayfish

1. Life history and production were assessed for the crayfish Paranephrops zealandicus in three reaches of a headwater stream with a catchment of regenerating coniferous-broadleaf forest in the south-east of the South Island of New Zealand.
2. Crayfish density ranged from 3 to 4 m⁻² in riffles and 4–12 m⁻² in pools, depending on reach. Crayfish biomass (4–33 g AFDW m⁻²) and annual production (2–11 g AFDW m⁻²) were high compared with values reported elsewhere, while P:B ratio was low (0.33–0.43). This substantial production was dependent primarily upon high biomass rather than high growth rate.
3. The crayfish of this population rank amongst the longest lived and slowest growing ever recorded. Individuals estimated to be 16+ year of age were not uncommon. Females became reproductively active at 6+ year. Fewer than 4% of females carried eggs, and young remained attached to females for at least 15 months.
4. We propose that characteristics of this population are the consequence of a cool thermal regime (mean daily stream temperature = 7.0 °C, range 1.8–11.9 °C), and that low biomass turnover and poor reproductive rate precludes any sustainable commercial harvest of crayfish from streams in New Zealand with similar thermal regimes.     

Plasma volume in acute hypoxia: comparison of a carbon monoxide rebreathing method and dye dilution with Evans'' blue

Exposure to acute hypoxia is associated with changes in body fluid homeostasis and plasma volume (PV). This study compared a dye dilution technique using Evans' blue (PV_Evans') with a carbon monoxide (CO) rebreathing method (PV_CO) for measurements of PV in ten normal subjects at sea level and again 24 h after rapid passive ascent to high altitude (4,350 m). Hypobaric hypoxia decreased arterial oxygen saturation to 79 (74–83)% (mean with 95% confidence intervals). The PV_Evans' remained unchanged from 3.49 (3.30–3.68) l at sea level to 3.46 (3.24–3.68) l at high altitude. In contrast PV_CO decreased from 3.39 (3.17–3.61) l at sea level to 3.04 (2.75–3.33) l at high altitude (P < 0.05). Compared with sea level, this resulted in an increase of the mean bias between the two methods [from 0.11 (−0.05–0.27) l at sea level to 0.43 (0.26–0.60) l at high altitude] so that the ratio between PV_Evans' and PV_CO increased from 1.04 (0.99–1.09) at sea level to 1.15 (1.06–1.24) at high altitude (P < 0.05). In conclusion, the two methods were not interchangeable as measures of hypoxia-induced changes in PV. The mechanism responsible for the bias remains unknown, but it is suggested that the results may reflect a redistribution of albumin caused by the combined effects in hypoxia of both an increased capillary permeability to albumin and a decrease in PV. As a result, the small perivascular compartment of albumin beyond the endothelium may increase without changes in the overall albumin distribution volume. Accepted: 31 October 1997     

Inter- and intrapopulation variation in thermal reaction norms for growth rate: evolution of latitudinal compensation in ectotherms with a genetic constraint

In ectotherms, lower temperatures in high-latitude environments would theoretically reduce the annual growth rates of individuals. If slower growth and resultant smaller body size reduce fitness, individuals in higher latitudes may evolve compensatory responses. Two alternative models of such latitudinal compensation are possible: Model I: thermal reaction norms for growth rates of high-latitude individuals may be horizontally shifted to a lower range of temperatures, or Model II: reaction norms may be vertically shifted so that high-latitude individuals can grow faster across all temperatures. Model I is expected when annual growth rates in the wild are only a function of environmental temperatures, whereas Model II is expected when individuals in higher latitudes can only grow during a shorter period of a year. A variety of mixed strategies of these two models are also possible, and the magnitude of horizontal versus vertical variation in reaction norms among latitudinal populations will be indicative of the importance of "temperature" versus "seasonality" in the evolution of latitudinal compensation. However, the form of latitudinal compensation may be affected by possible genetic constraints due to the genetic architecture of reaction norms. In this study, we examine the inter- and intrapopulation variations in thermal reaction norms for growth rate of the medaka fish Oryzias latipes. Common-environment experiments revealed that average reaction norms differed primarily in elevation among latitudinal populations in a manner consistent with Model II (adaptation to "seasonality"), suggesting that natural selection in high latitudes prefers individuals that grow faster even within a shorter growing season to individuals that have longer growing seasons by growing at lower temperatures. However, intrapopulation variation in reaction norms was also vertical: some full-sibling families grew faster than others across all temperatures examined. This tendency in intrapopulation genetic variation for thermal reaction norms may have restricted the evolution of latitudinal compensation, irrespective of the underlying selection pressure.     

Life history and population dynamics of a tree species in tropical semi‐arid climate: A case study with Cordia oncocalyx

In semi‐arid climates, plant population dynamics are strongly influenced by the amount and temporal distribution of rainfall. We monitored a population of the tree species Cordia oncocalyx (Boraginaceae) for 24 months in the dry thorny woodland of semi‐arid northeastern Brazil, to investigate which life‐history traits allow this tree to be locally dominant. We used horizontal life tables and a Lefkovitch matrix and tested for relationships among demographic parameters of seedling, infant, juvenile, immature, virginile and reproductive ontogenetic stages with rainfall and canopy openness. Germination and recruitment occurred in the rainy months, and dry‐season mortality occurred only in seedlings (76% and 100%, first and second years, respectively) and infants (3% and 6%). Juveniles showed greater height growth under more open canopies (Spearman correlation coefficient = 0.24), suggesting that light availability influences growth. The population growth rate was λ = 1.0336, and the highest sensitivity occurred in the infant‐juvenile transition. Our results show light as a restrictive growth factor for plants in the juvenile stage and confirm the strong influence of rainfall on the dynamics of trees in a seasonally dry environment. The formation of a persistent seed bank with germination concentrated at the rainfall onset but spreading over the rainy season are strategies that hedge bets before establishment. The formation of a bank of infants, which can resume growth as soon as there is water, hedges bets after establishment. We attribute the positive population growth rate of Cordia oncocalyx to survival strategies allowing bet‐hedging both before and after establishment.     

Mutational analysis of the interaction between insulin receptor and IGF-I receptor with c-Crk and Crk-L in a yeast two-hybrid system

The SH2/SH3 adapter proteins of the Crk family are potent signal transducers after receptor tyrosine kinase stimulation with insulin or IGF-1. We have employed a yeast two-hybrid approach and mutational analysis to dissect the capabilities of the insulin receptor and the IGF-I receptor to directly associate with Crk isoforms. Insulin receptor stably recruits full length Crk by association with its SH2 domain in an auto-phosphorylation dependent manner. In contrast, interaction of the IGF-I receptor with the Crk-IISH2 domain was only detectable when Crk-II was truncated in its C-terminal part, indicating the transient nature of this interaction. From these data it can be concluded that members of the insulin receptor family activate Crk proteins in a differential manner.     

长期慢病患者单次精准功率运动前后脉搏波波形特征个体化分析研究*

目的: 观察研究长期慢病患者的静息桡动脉脉搏波及单次个体化运动后脉搏波的变化情况。方法: 选取被明确诊断为高血压和（或）糖尿病和（或）高脂血症的长期（病程≥5年）慢病患者16例,完成症状限制性极限心肺运动试验（CPET）,计算Δ50%功率为个体化精准运动强度,完成持续30 min的单次个体化运动。于运动前和运动后10 min、20 min、30 min分别测量50 s桡动脉脉搏波,得到每个脉搏波特征点：起始点（B）、主波波峰点（P1）、重搏波波谷点（PL）、重搏波波峰点（P2）、结束点（E）,从仪器中导出各点对应的横坐标（时间T）和纵坐标（幅值Y）的原始数据,将上一个脉搏波的结束点E视为下一个波的起始点B,TB归零,得到主要观察指标：YB、YP1、YPL、YP2及TP1、TPL、TP2、TE,并计算出ΔYP1、ΔYPL、ΔYP2,TE-TPL、（TE-TPL）/TPL、脉率,S1、S2,ΔYP2-ΔYPL、TP2-TPL作为次要观察指标;计算波峰明显的重搏波出现率;对每位患者运动前后的50 s脉搏波数据个体化分析,再将所有数据求均值进行整体分析。结果: ①16例长期慢病患者(男14女2）,年龄（53.7±12.6,28~80）岁,身高（171.7±6.6, 155~183）cm,体质量（80.0±13.5, 54~98）kg。2静息时YB（91.5±10.8,71.1~108.6）、YP1（203.6±24.7,162.7~236.3）、YPL（127.1±6.2,118.2~140.3）、YP2（125.9±6.2,115.7~137.7）、TP1（137.2±22.3,103.0~197.1）、TPL（368.7±29.5,316.3~434.0）、TP2（422.7±32.8,376.9~494.7）、TE（883.4±95.0,672.2~1003.3）,ΔYP1（112.1±33.8,60.3~157.5）、ΔYPL（35.5±14.2,17.5~66.2）、ΔYP2（34.4±13.3,20.0~62.9）、TE-TPL（514.6±85.4,341.4~621.9）、(TE-TPL)/TPL（1.4±0.2,1.0~1.7）、脉率（68.8±8.4,59.8~89.3）、S1（0.9±0.3,0.4~1.4）、S2（0.0±0.0,-0.1~0.0）、ΔYP2-ΔYPL（-1.2±2.6, -6.5 ~2.5）、TP2-TPL（54.0±10.8,33.6~81.1）。③运动后10 min,YB、 YPL、YP2、TPL、TE减小,YP1增大;ΔYPL、TE-TPL、（TE-TPL）/TPL减小,而ΔYP1、脉率、S1、ΔYP2-ΔYPL、 TP2-TPL增大（P均<0.05）。运动后20 min和30 min的脉搏波变化趋势与运动后10 min保持一致,但从10 min后大部分指标逐渐向静息水平恢复。④静息时16例长期慢病患者波峰明显的重搏波出现率为28.6%,运动后10 min（65.7%）、20 min（77.1%）、30 min（73.7%）的出现率明显提高（P均<0.01）。其中6例患者运动后波峰明显的重搏波出现率显著升高,且能持续到30 min;3例患者运动后10 min出现率上升明显,20 min时开始下降;1例患者运动后20 min出现率才开始升高;2例患者运动后10 min出现率升高后随即下降;1例患者运动后20 min出现率短暂升高后下降;1例患者运动后出现率下降,20 min时开始回升;2例患者运动后出现率不升,30 min时稍有升高。结论: 长期慢病患者的桡动脉脉搏波波形矮小,重搏波不明显甚至消失,单次精准功率运动后,主波增高,重搏波位置降低、幅度增大;具体反应情况应个体化分析。     

Mycelial growth of strains of the genera <Emphasis Type="Italic">Suillus</Emphasis> and <Emphasis Type="Italic">Boletinus</Emphasis> in media with a wide range of concentrations of carbon and nitrogen sources

Suillus and Boletinus were studied using Ohta medium. In media with glucose or trehalose, all tested strains grew well. With mannose and cellobiose, strains generally grew well, except for one strain of Suillus. Utilization of dextrin and soluble starch differed with each strain, and that of sucrose and glycerol was low for all strains. Utilization of four amino acids, arginine, glutamic acid, aspartic acid, and alanine, was similar to that of ammonium tartrate for Suillus strains, but mycelial growth with amino acids was clearly lower than with ammonium tartrate for the Boletinus strain. The effect of glucose and ammonium tartrate concentrations for nine strains of the genera Suillus and Boletinus was studied with ranges for glucose of 1–100 and 200g/l, respectively, and for ammonium tartrate of 0.2–5 and 20g/l, respectively. Six strains showed maximal growth at a glucose concentration greater than 25g/l, and one strain showed maximal growth at 70g/l. The results indicate that these fungi are adapted to relatively high concentrations of carbon sources. In general, glucose concentration at mycelial growth maximum decreased as ammonium tartrate concentration increased, and at higher concentrations of glucose, mycelial growth decreased more rapidly in higher concentrations of ammonium tartrate.