Effect of temperature on low-strength wastewater treatment by UASB reactor using poly(vinyl alcohol)-gel carrier

The feasibility of treating low-strength wastewater with an up-flow anaerobic sludge blanket (UASB) reactor, using a poly(vinyl alcohol)-gel carrier, at various temperatures and hydraulic retention times (HRTs) was examined. The temperature was decreased from 35°C to 25°C and then to 15°C. The HRT was reduced from 2.0 h to 0.22 h. The COD removal rate reached 28 kg-COD m(-3)d(-1) at 35°C, 16 kg-COD m(-3)d(-1) at 25°C, and 6 kg-COD m(-3)d(-1) at 15°C. The COD removal rate was reduced by half for each temperature reduction of 10°C.     

Effect of starch addition on the biological conversion and microbial community in a methanol-fed UASB reactor during long-term continuous operation

The effect of starch addition on the microbial composition and the biological conversion was investigated using two upflow anaerobic sludge bracket (UASB) reactors treating methanolic wastewater: one reactor was operated with starch addition, and another reactor was operated without starch addition. Approximately 300 days of operation were performed at 30 kg COD/m³/d, and then, the organic load of the reactors was gradually increased to 120 kg COD/m³/d. Successful operation was achieved at 30 kg COD/m³/d in both reactors; however, the methanol-fed reactor did not perform well at 120 kg COD/m³/d while the methanol-starch-fed reactor did. The granule analysis revealed the granule developed further only in the methanol-starch-fed reactor. The results of the microbial community analysis revealed more Methanosaeta cells were present in the methanol-starch-fed reactor, suggesting the degradation of starch produced acetate as an intermediate, which stimulated the growth of Methanosaeta cells responsible for the extension of granules.     

Effect of chitosan on UASB treating POME during a transition from mesophilic to thermophilic conditions

The effects of chitosan addition on treatment of palm oil mill effluent were investigated using two lab-scale upflow anaerobic sludge bed (UASB) reactors: (1) with chitosan addition at the dosage of 2 mg chitosan per g volatile suspended solids on the first day of the operation (R1), (2) without chitosan addition (the control, R2). The reactors were inoculated with mesophilic anaerobic sludge which was acclimatized to a thermophilic condition with a stepwise temperature increase of 5 °C from 37 to 57 °C. The OLR ranged from 2.23 to 9.47 kg COD m⁻³ day⁻¹. The difference in biogas production rate increased from non-significant to 18% different. The effluent volatile suspended solids of R1 was 65 mg l⁻¹ lower than that of R2 on Day 123. 16S rRNA targeted denaturing gradient gel electrophoresis (DGGE) fingerprints of microbial community indicated that some methanogens in the genus Methanosaeta can be detected in R1 but not in R2.     

Effect of different feeding strategies on lactation performance of Holstein and Normande dairy cows

The dairy farming systems of Western Europe are based on a simple feeding system composed of grazed and preserved grass, maize silage and concentrates in variable proportions. There is, nevertheless, a great diversity of feeding strategies between dairy farms. Over 5 years, we studied the direct and delayed effects of four feeding strategies on the lactation and reproduction performances of Holstein and Normande dairy cows. The four feeding strategies (denoted Hh, Hl, Lh and Ll) correspond to two total mixed rations applied in winter from calving to turnout (maize silage with 30% concentrate or grass silage with 15% concentrate), which were subsequently crossed with two levels of concentrate supplementation at grazing to 210 days. Each year, 72 dairy cows managed in grouped winter calving were assigned to the four strategies. Finally, the results of 325 lactations and 295 inseminated cows were analysed. The four strategies resulted in considerable variation in nutrient intake and, in particular, in differences in concentrates consumed, with values of 1407, 1026, 773 and 392 kg dry matter per cow for strategies Hh, Lh, Hl and Ll, respectively. Total milk production (7567, 7015, 6720 and 6238 kg per cow for treatments Hh, Lh, Hl and Ll, respectively), milk fat content (39.0, 37.1, 40.3 and 38.5 g/kg, respectively), milk protein content (33.0, 31.8, 33.1 and 31.6 g/kg, respectively), and the character of the lactation and body condition curves were all highly sensitive to the strategies applied. While no significant interaction was detected on total lactation yield, the Holstein cows reacted more dramatically to each dietary change at each period, compared with the Normande cows. Winter feeding did not affect the production of milk at pasture whereas, at pasture, the milk from the cows of the H groups in winter was higher in milk fat and protein content. Reproduction performance was unaffected by feeding strategy. The Holstein cows, well fed and producing the most milk (Hh and Hb), had the lowest rate of success at first artificial inseminations (21.5%). The dual-purpose Normande cows had a pregnancy rate 10 points higher than Holstein cows. This comparison of strongly contrasting feeding strategies confirms the immediate reactivity of dairy cows (in terms of milk performance and body condition) to variations of nutritive intake throughout lactation, with a weak carryover effect from feeding levels early in lactation. In contrast, reproduction performance was less sensitive to variation in nutrient supply.     

Research note: Effect of duration of the collection period on the estimated digestibility in dairy cows

A digestion trial was performed with 14 lactating Friesian dairy cows to compare the estimated digestibility of crude nutrients after collecting the faeces for 5, 7 and 9 d. The experimental ration consisted of grass silage (7.3 kg DM) and concentrate (10.9 kg DM). Animals were adapted to the ration for 14 d. There was no effect of the duration of the collection period on the estimated mean digestibility of crude nutrients and on the respective standard deviation. In consequence, in digestibility trials with cows the collection period must not exceed 5 d.     

Effect of season on luteal activity during the post partum period of dairy cows in temperate areas

Seasonal effects on luteal activity during post partum were evaluated in two consecutive studies in 253 dairy cows in Northern Italy. In study 1, plasma progesterone concentrations were determined on days 14, 21, 28, 35, 42, 49 and 56 post partum and in study 2 cows were synchronized and inseminated at a fixed time using two regimes based on the 'Ovsynch' protocol. Study 1: Animals were classified as luteal (progesterone >1.5 ng/ml in at least two consecutive samples) or non-luteal (progesterone <1.5 ng/ml in all samples). The proportion of cows without luteal activity from calving to day 56 post partum was 47/253 (18.5%). Of the 47 cows without luteal activity, 42 (89%) were detected during the warm months of the year and five were detected during the cold months of the year, and the effect of season was highly significant (P < 0.001). Study 2: Three study groups were established; control (CONT, untreated cows, n = 92), GPG (cows receiving gonadotropin-releasing hormone (GnRH) on day 0, PGF2α on day 7 followed by a second dose of GnRH 24 h later, n = 80); and HPH (the same as the GPG group, but with human chorionic gonadotropin (hCG) substituted for GnRH, n = 81). In the GPG and HPH groups, cows were inseminated 16 to 22 h after the second GnRH or hCG injection. Untreated cows were inseminated at first estrus after a voluntary weaning period. Because the effects of the GPG and HPH regimes on pregnancy rate were not significantly different, data were pooled into a single treatment group (TREAT). Pregnancy rates during the warm months of the year were 16% and 15% at first service and 65% and 66% at day 135 post partum for CONT and TREAT groups, respectively. Pregnancy rates during the cold months of the year were 36% and 38% at first service and 72% and 76% at day 135 post partum for CONT and TREAT groups, respectively. There was an effect of season (P < 0.05) but not of treatment on pregnancy rate. Treatment reduced the number of days from calving to conception during both the cold (101 ± 3.2 v. 121 ± 3.1 days; P < 0.001) and warm seasons (122 ± 3.2 v. 145 ± 3.1 days; P < 0.001). In conclusion, the present study shows that (i) heat stress during the warm season can compromise luteal activity and (ii) that regimes based on the Ovsynch protocol did not improve pregnancy rate at first service or by 135 post partum, but they had a positive effect on the calving-to-conception interval.     

The effect of temporary deprivation of lying and feeding on the behaviour and production of lactating dairy cows

Two experiments were conducted to examine the effects of depriving dairy cows of the ability to feed and lie down for short periods, on behaviour and production. In experiment 1, cows were deprived by confining them in pairs in a pen for 2 or 4 h, and they more frequently exhibited behaviour likely to suggest discomfort - leg stamping, repositioning themselves, shifting their weight between legs and butting. After deprivation, the cows deprived for 2 h made up their lost feeding time within 24 h, but cows deprived for 4 h did not restore their feeding time within the 41-h period of observation. Lying time was not restored in either treatment within the 41-h period. Milk yield was not affected by the treatment. However, in experiment 2, when cows were deprived of feeding and lying for 4 h, during which time their hooves were trimmed (which is likely to be a painful and stressful procedure and result in some discomfort for a period post-trimming) the evidence suggested that milk yield was reduced by approximately 2 l/day for 3 days, with corresponding increases during the subsequent 2 days. Walking speed on returning to the herd was the same as before the treatment. In summary, temporary deprivation of feeding and lying for 2 and 4 h/day induced behaviours that were indicative of discomfort and frustration but had no negative effect on milk production, except when 4 h of deprivation was accompanied by foot trimming.     

The effect of lactation length on greenhouse gas emissions from the national dairy herd

Many governments have signed up to greenhouse gas emission (GHGE) reduction programmes under their national climate change obligations. Recently, it has been suggested that the use of extended lactations in dairy herds could result in reduced GHGE. Dairy GHGE were modelled on a national basis and the model was used to compare emissions from lactations of three different lengths (305, 370 and 440 days), and a current ‘base’ scenario on the basis of maintaining current milk production levels. In addition to comparing GHGE from the average ‘National Herd’ under these scenarios, results were used to investigate how accounting for lactations of different lengths might alter the estimation of emissions calculated from the National Inventory methodology currently recommended by Intergovernmental Panel on Climate Change. Data for the three lactation length scenarios were derived from nationally recorded dairy performance information and used in the GHGE model. Long lactations required fewer milking cows and replacements to maintain current milk yield levels than short ones, but GHGEs were found to rise from 1214 t of CO₂ equivalent (CE)/farm per year for lactations of 305 days to 1371 t CE/farm per year for 440-day lactations. This apparent anomaly can be explained by the less efficient milk production (kg milk produced per kg cow weight) found in later lactation, a more pronounced effect in longer lactations. The sensitivity of the model to changes in replacement rate, persistency and level of milk yield was investigated. Changes in the replacement rate from 25% to 20% and in persistency by −10% to +20% resulted in very small changes in GHGE. Differences in GHGE due to the level of milk yield were much more dramatic with animals in the top 10% for yield, producing about 25% less GHGE/year than the average animal. National Inventory results were investigated using a more realistic spread of lactation lengths than recommended for such calculations using emissions calculated in the first part of the study. Current UK emission calculations based on the National Inventory were 329 Gg of methane per year from the dairy herd. Using the national distribution of lactation lengths, this was found to be an underestimate by about 10%. This work showed that the current rise in lactation length or a move towards calving every 18 months would increase GHGE by 7% to 14% compared with the current scenario, assuming the same milk yield in all models. Increased milk yield would have a much greater effect on reducing GHGE than changes to lactation length, replacement rate or persistency. National Inventory methodology appears to underestimate GHGE when the distribution of lactation lengths is considered and may need revising to provide more realistic figures.     

乳品废水中蛋白质降解的最佳工艺条件研究

对乳品加工废水处理过程中的蛋白质含量的降解和蛋白酶活力以及COD进行了测试,找出在厌氧发酵下的一些关键影响参数：温度、pH值、泥水比以及厌氧发酵时间。根据各单因素测验结果设计了四因素、三水平的正交试验。通过极差分析我们得出温度为30℃,pH为7．0,发酵时间为4天,泥水比为1：11．5的厌氧处理蛋白质的最优化工艺条件。     

High-energy forage feeding diets and body condition on the finishing of cull dairy cows

Combinations of two high-energy forage finishing diets and two initial body condition scores (BCSs) in a 2 × 2 factorial experimental design were evaluated on cull Holstein–Friesian (HF) cows to improve animal performance and carcass characteristics, aimed at achieving proper fatness and conformation scores (a minimum of ‘4’ and ‘O’, respectively) required for the marketing of high-value loin steaks. The two finishing diets were (i) conventional maize silage complemented with concentrate diet and (ii) wet maize ear silage (pastone) complemented with dry-herbage diet. The two initial body condition levels were (i) low BCS < 5 (LBCS) and (ii) high BCS > 5 (HBCS). The HBCS animals had the greatest potential to respond to the finishing diets. They needed a smaller total feed intake (TFI) and a shorter finishing period (FP) to meet the marketing requirements. The average feed budgets necessary to finish cull dairy cows and to achieve the minimum scores ‘4’ and ‘O’ of carcass classification were 2.31 and 3.61 t of dry matter (DM)/cow for HBCS and LBCS animals, respectively, while the FP lasted an average of 143 and 224 days for HBCS and LBCS animals, respectively. With regard to the two feeding diets, we found no differences for TFI, carcass characteristics and loin muscle features, such as weight, diameter and intramuscular fat.     

Effect of ferrous ion on the biological activity in a UASB reactor: mathematical modeling and verification

The effect of ferrous ion on the biological activity in a upflow anaerobic sludge blanket (UASB) reactor was studied. A mathematical model was developed and validated in order to simulate the dynamic behavior of a UASB reactor. This model took into consideration of all the biological and physicochemical reactions. The model was able to simulate the accumulation of iron in the sludge bed and its effect on the biological activity of the anaerobic sludge. A significant increase in the maximum uptake rate of methanogens and acidogens was revealed when iron was supplemented to the UASB reactor. The addition of ferrous iron induced a stable and excellent COD conversion rate. The model can be a useful tool for the prediction of process performance in the future and can be used to assist in the operation of biogas plants. The ferrous ion addition proved to enhance the biological activity of UASB sludge. Thus, the model can be used for the design of treatment plants that will take advantage of the benefits of iron addition.     

Effect of short-range forces on the length distribution of fibrous cytoskeletal proteins

The length distribution of cytoskeletal filaments is an important physical parameter, which can modulate physiological cell functions. In both eukaryotic and prokaryotic cells various biological cytoskeletal polymers form supramolecular structures due to short-range forces induced mainly by molecular crowding or cross linking proteins, but their in vivo length distribution remains difficult to measure. In general, based on experimental evidence and mathematical modeling of actin filaments in aqueous solutions, the steady state length distribution of fibrous proteins is believed to be exponential. We performed in vitro TIRF- and electron-microscopy to demonstrate that in the presence of short-range forces, which are an integral part of any living cell, the steady state length distributions of the eukaryotic cytoskeletal biopolymer actin, its prokaryotic homolog ParM and microtubule homolog FtsZ deviate from the classical exponential and are either double-exponential or Gaussian, as recent theoretical modeling predicts. Double exponential or Gaussian distributions opposed to exponential can change for example the visco-elastic properties of actin networks within the cell, influence cell motility by decreasing the amount of free ends at the leading edge of the cell or effect the assembly of FtsZ into the bacterial Z-ring thus modulating membrane constriction.     

Effect of D-penicillamine on rat lung elastin cross-linking during the perinatal period

This study was designed to clarify the effects of D-penicillamine (DPA), a drug used for treatment of various pathological events, on lung elastin formation and maturation of the newborn in the perinatal period. The investigation was conducted on 20 newborn rats bred from 40 female and six male rats. DPA doses 400 mg kg(-1) day(-1) and physiological saline were given intraperitoneally (i.p) to experimental and control groups. To assess newborn maturation, their body and lung weights were determined. Serum Cu levels were measured by atomic absorption spectroscopy and ceruloplasmin (Cp) activities were measured spectrophotometrically. Newborn lung tissue elastin, desmosine (DES) and isodesmosine (IDES) levels were measured by HPLC. The results showed that DPA treatment caused loss of skin elasticity and reduction in body and lung weight in newborns of the experimental group. The serum Cu levels and Cp activity were found to be significantly lower in both maternal and newborn of the experimental groups compared with the control group. The lung DES, IDES and elastin values of newborns in the experimental group were decreased compared with the control group. In conclusion, our results indicate that 400 mg kg(-1) day(-1) DPA, a dose that is used in the treatment of Wilson's disease, rheumatoid arthritis and cystinuria, caused the retardation of newborn maturation, a decrease in DES-IDES cross-links and levels of lung elastin of offspring in the perinatal period. Another conclusion to be drawn from this study is that even low levels of Cu depletion due to DPA administration induces a change in cross-linking in lung elastin during the perinatal period.     

Effect of chronic intermittent hypoxia on biological behavior and hypoxia‐associated gene expression in lung cancer cells

Hypoxia plays an important role in the development of solid tumors and is associated with their therapeutic resistance. There exist three major forms of hypoxia: acute, chronic, and intermittent hypoxia. Previous studies have shown that cancer cells could behave in the form of adaptation to hypoxia in tumor growth, which could result in their biological changes and determine their responses to the therapies. To investigate the tumor cells' adaptation to hypoxia, we recreated two models using two lung cancer cell lines in the presence of intermittent hypoxia, which is characterized by changes in oxygen pressure within the disorganized vascular network. We investigated biological behaviors such as cell cycle, proliferation, radiation sensitivity, apoptosis and migration, hypoxia signal pathway in the lung cancer cells treated with chronic intermittent hypoxia, as well as the role of hypoxia inducible factor 1 there, hypoxia‐inducible genes analyzed by real‐time RT‐PCR chip in H446 cells treated with the model. The results indicated the changes of some hypoxia target gene expressions of those induced by hypoxia, some of which were confirmed by real‐time RT‐PCR. The cells mediated by irradiation induced resistance to radiation and apoptosis and increased metastasis in lung cancer cells. It was found that such changes were related to hypoxia inducible factor 1, alpha subunit (HIF‐1α). J. Cell. Biochem. 111: 554–563, 2010. © 2010 Wiley‐Liss, Inc.     

Effect of addition of one carbon source on the operation of sequencing batch reactor in order to remove nitrogen and COD from poultry wastewater

The effect of carbon source addition on the operation of a sequencing batch reactor in order to remove nitrogen and COD of poultry wastewater was studied. The reactor was constructed with a glass tube having a volume of 7 l and a jacket for temperature control. The reactor bottom consisted of a conical porous stone in order to promote liquor aeration and agitation. Initial conditions and operation strategies were adjusted to improve the final effluent quality. According to the attained experimental results, it was verified that nitrification and denitrification can occur simultaneously in aerated culture, contrary the observation of some authors.     

Recovery strategies for tackling the impact of phenolic compounds in a UASB reactor treating coal gasification wastewater

The impact of phenolic compounds (around 3.2 g/L) resulted in a completely failed performance in a mesophilic UASB reactor treating coal gasification wastewater. The recovery strategies, including extension of HRT, dilution, oxygen-limited aeration, and addition of powdered activated carbon were evaluated in batch tests, in order to obtain the most appropriate way for the quick recovery of the failed reactor performance. Results indicated that addition of powdered activated carbon and oxygen-limited aeration were the best recovery strategies in the batch tests. In the UASB reactor, addition of powdered activated carbon of 1 g/L shortened the recovery time from 25 to 9 days and oxygen-limited aeration of 0-0.5 mgO₂/L reduced the recovery time to 17 days. Reduction of bioavailable concentration of phenolic compounds and recovery of sludge activity were the decisive factors for the recovery strategies to tackle the impact of phenolic compounds in anaerobic treatment of coal gasification wastewater.     

负重深蹲中施加不同动脉闭塞压和间歇方式对大腿肌肉激活特征的影响

目的: 通过探讨负重深蹲练习中施加不同动脉闭塞压和间歇方式对大腿肌群激活特征的影响,找出引起最大激活的个人适宜动脉加压相对值范围,为运动员科学进行加压训练提供一定的理论依据和实践参考。方法: 募集10名男子运动员,进行负重30%1RM(最大抗阻百分比)的深蹲练习,以间歇加压和持续加压两种模式,分别完成无加压、40%动脉闭塞压(AOP)、50%AOP和60%AOP四种加压形式。运用Wave plus无线表面肌电测试仪采集大腿肌群的表面肌电信号,计算出大腿前、后肌群的肌电振幅值。采用双因素方差分析考察通过施加不同动脉闭塞压和不同间歇休息模式对大腿肌肉群的激活效应及其差异。结果: ① 经过双因素方差分析,通过施加不同AOP对所测肌肉标准化均方根振幅值具有显著性影响(P＜0.05),而间歇方式则对所测大腿肌群%MVC值无显著性影响(P＞0.05),施加不同动脉闭塞压和间歇方式对所测肌肉肌电活动的交互作用均无显著性(P＞0.05);② 30%1RM负重深蹲练习时,在50%AOP压力条件下,间歇和持续加压都可以显著提高股直肌、股内侧肌、股外侧肌、股二头肌和半腱肌的%MVC值(P＜0.05);③ 40%AOP压力条件下,仅间歇深蹲练习可显著提高股直肌的%MVC值(P＜0.05);60%AOP压力条件下,也仅间歇练习可以显著提高股内侧肌和半腱肌%MVC值(P＜0.05)。结论: 本研究进一步验证了50%AOP施压对高水平手球运动员在轻负重蹲起练习可以同时显著提高股四头肌和股后肌群的最佳激活程度,产生最佳训练效果,间歇模式推荐采用除压间歇模式。     

多巴胺对急性间歇性低氧诱导的大鼠颈动脉体低氧敏感性的影响

目的:观察急性间歇性低氧刺激后大鼠颈动脉体对低氧的敏感性以及多巴胺对颈动脉体低氧敏感性的影响。方法:将分离SD大鼠的颈动脉体-窦神经移入到孵育槽,然后把分离的窦神经吸入到记录的玻璃电极中行电信号记录。记录基线部分缓冲液充入气体为95%O2+5%CO2混合气,低氧应激给予5%O2+5%CO2+90%N2混合气,低氧刺激给予30 s,95%O2+5%CO2给予90 s,共10个循环,每组实验大鼠数量n大于等于5。结果:大鼠离体的颈动脉体,给予急性间歇性低氧应激,再给予低氧刺激,窦神经较之前低氧刺激放电活动增强。但加入多巴胺后,可以抑制窦神经对低氧的反应,急性间歇性低氧后,多巴胺对窦神经的低氧放电活动抑制作用加强。结论:大鼠颈动脉体给予急性间歇性低氧可增强窦神经对低氧的反应,多巴胺可抑制急性低氧诱导的颈动脉体对低氧敏感性的增强。     

Effect of the rate of increase in concentrate allowance with concentrates high or low in starch on the performance of dairy cows in early lactation

The effect of the rate of increase in concentrate allowance after calving with two concentrate mixes (A and B) differing in composition was evaluated using 64 Finnish Ayrshire cows during the first 100 days of lactation. After calving, the concentrate allowance of multiparous cows was increased stepwise from 4 to 17 kg/day, and of primiparous cows from 3 to 13.5 kg/day over 12 days (F rate of increase; multiparous 1.08 kg/day, primiparous 0.88 kg/day) or 24 days (S rate of increase; mutiparous 0.54 kg/day, primiparous 0.44 kg/day). The concentrates were formulated to have similar crude protein and metabolizable energy concentrations but differing starch and NDF concentrations. For concentrate A the starch and NDF concentrations were 421 and 167 g/kg dry matter (DM) and for concentrate B 258 and 251 g/kg DM. All cows received grass silage ad libitum. The higher concentrate intake during weeks 1 to 4 of lactation with F compared with the S rate of increase caused higher DM, energy and protein intake. The higher concentrate intake for F than for S treatment in early lactation did not cause a large decrease in silage intake (8.8 v. 8.3 kg DM/day). The intake of concentrate A and B after calving did not differ for S treatment. However, for F treatment the intake of fibrous concentrate B increased faster than starch-rich concentrate A during weeks 1 to 4 of lactation. The concentrate composition had no effect on energy-corrected milk (ECM) yield during weeks 1 to 4 of lactation for S treatments, but with F treatments the cows fed B concentrate produced more milk. The F rate of increase in concentrate allowance compared with the S rate increased the calculated energy balance after calving. The rate of increase in concentrate feeding post partum or concentrate composition had no effect on DM, energy or protein intake during the whole 100-day experiment. The average ECM yield over days 1 to 100 of lactation was higher for S than for F treatments and tended to be higher with concentrate B than A. Results of this study showed that by the fast rate of increase in concentrate allowance after calving on a grass silage diet, it was possible to improve the energy status of the cows in early lactation. This had, however, no effect on production later in lactation.