胶体滴定技术与湿部化学过程的控制

本文阐述了胶体滴定技术的原理；测定纸料中可溶性电解质的阴离子需求量或阳离子需求量的方法和步骤，以及影响胶体滴定结果的因素=胶体滴定比值（CTR）与造纸湿部过程中的留着率、白水浓度、电导率等有着密切的关系。因此，胶体滴定比值可以作为控制造纸湿部化学过程的手段。     

简便的纸料电性分析方法

本文介绍了一种利用胶体滴定技术测试和研判纸料整体电性的简便分析方法.其关键技术在于反滴定法的灵活应用以及对滴定终点的明确指定.根据试验过程中标准溶液PVSK、DPPM的加入量和消耗量,可以分别计算出纸料的阳离子需求量、阴离子需求量及胶体滴定比CTR.根据CTR的值判断纸料的电性及其强弱.CTR值接近1,纸料的电性呈中性;CTR越大,纸料的阳离子性越强;CTR越小,纸料阴离子性越强.该方法有利于造纸系统的湿部过程检验和生产控制.     

胶体滴定技术中应用的化学试剂及其发展

胶体滴定技术是造纸湿部电荷分析的重要方法。介绍了胶体滴定技术的原理 ,应用的化学试剂———标准聚合电解质、指示剂和基准物 ,以及胶体滴定技术的应用     

利用胶体滴定技术进行造纸湿部电荷分析

重点讨论了利用胶体滴定技术进行造纸湿部化学分析的原理和方法,论述了造纸系统电荷分析的意义以及造纸配料中静电荷的来源和性质。     

造纸湿部电荷检测技术与设备

阐述了Zeta电位和胶体滴定在造纸湿部电荷检测中的应用及相应的检测设备。     

造纸法再造烟叶纸机湿部环境初探

利用Zeta电位仪和PCD颗粒电荷测定仪,对造纸法再造烟叶的浆料流送系统及湿部的Zeta电位和阴离子垃圾含量进行检测。结果表明,在一个生产周期内,流浆箱内浆料的Zeta电位平均值为-7.06 mV,阳离子需求量平均值高达970μmol/L,浆料中阴离子垃圾主要来自浓白水。     

造纸湿部电荷的检测技术

随着造纸工业的发展,各类造纸化学品的相继使用,使得造纸湿部的电荷变化日趋复杂,而湿部的电荷分析是应付纸机各种变化的一种有力工具,达到优化和稳定造纸湿部的目的.主要介绍了胶体电荷检测的动电学现象和胶体滴定法,并且对这两种方法的原理、特点和在线电荷的测量以及电荷分析的意义进行了讨论.     

利用胶体滴定对纸浆悬浮液进行电荷分析

介绍了利用胶体滴定技术进行电荷分析的方法，对多种纸浆的可溶电荷需求量、表面阴电荷需求量、表面阳电荷需求量和胶体滴定比率进行了测定，研究了纸浆PH值、电导率、浓度和打浆度对胶体滴定测得电荷密度的影响。对利用胶体滴定法进行纸浆悬浮液电荷分析的条件提出了建议。     

造纸湿部阴离子垃圾的影响因素及处理

随着白水封闭程度的提高,在造纸湿部化学中带负电荷的溶解和胶体物质(DCS)的积累也越来越多.由于DCS具有比纤维和填料等造纸原料更小的体积和更大的比表面积,所以它们可以优先与加入系统中的各种阳离子型助剂发生反应,增加系统阳电荷需求量,从而使阳离子型助剂在低用量下失效[1].阴离子垃圾的主要成分包括:聚半乳糖醛酸类物质(聚半乳糖醛酸、果胶酸等)、氧化木素以及脂肪酸和树脂酸等.     

溶解电荷和表面电荷为零对湿部流送系统所产生的影响

荷兰的Brouwer博士在1990年Papermaking Conference学术讨论会上曾经提出了一种旨在优化纸机湿部化学助剂添加方案的湿部化学法，即：除了测定浆料体系的Zeta电位（溶解电荷和表面电荷）之外，还应该测定其阴/阳离子需求量；如果阳离子需求量很高，就应该用合适的阴离子垃圾捕捉剂来对浆料进行处理；使用高分子质量、低电荷密度的助留剂；使纸机在上网浆料系统表面电荷和溶解电荷都接近于零时运行。     

纸浆悬浮液胶体滴定比率的初步研究

采用胶体滴定方法,研究了纸浆悬浮液的胶体滴定比率（ＣｏｌｏｉｄＴｉｔｒａｔｉｏｎＲａｔｉｏ,简称ＣＴＲ）特性及其影响因素;还用动态滤水试验仪验证了ＣＴＲ值对湿部留着和滤水的相关性。初步研究表明,通过控制纸浆悬浮液的ＣＴＲ值,可优化造纸化学助剂的添加工艺     

造纸湿部中施胶铝盐的电荷分析

运用胶体滴定方法对几种施胶铝盐在施胶时的造纸湿部浆料电荷变化进行了研究.结果表明,随着聚合氯化铝-有机高分子复合物(PACP)用量的逐渐增加,麦草浆的胶体滴定比率(CTR值)明显增大;加入相同用量的PAC或PACP时,纸浆的CTR值随pH值的增大而增大;在相同pH值及相同用量的条件下,CTR值由高到低的顺序为PACPc＞PAC＞PACPa.对于PACPa,CTR值随有机高分子/铝比值(O/A)的增加而降低;而PACPc的CTR值随该比值的增加而增加.     

Children's Acceptance, Nutritional, and Instrumental Evaluations of Whole Grain and Soluble Fiber Enriched Foods

ABSTRACT:  The Dietary Guidelines for Americans 2005 report recommends 3 or more daily ounce-equivalents of whole grains (WG), and the FDA suggests consumption of 25 g of total dietary fiber (TDF) and 6 g of soluble fiber (SF) for a 2000-calorie diet. Efforts to increase the consumption of WG and SF among elementary school-aged children are needed. The objectives of this study were to examine the consumption of WG- and SF-enriched burritos and cookies among elementary school-aged children and to perform a quality evaluation of all products. Children in grades K to 6 from a local elementary school consumed control (CTR) products made with refined flour along with the test products (TRT) over a 13-wk period. TRT burritos and cookies contained 51% and 100% WG, respectively. CTR and TRT products were served on 3 and 4 different Fridays, respectively. Children's consumption was determined via plate waste. Quality parameters such as texture, color, water activity, weight, and product dimensions were also measured. No significant differences in consumption between CTR and TRT burritos and cookies were found (36% and 90%, respectively). Texture (area) was higher for CTR burritos compared with TRT burritos (1.31 and 0.66 kg-s, respectively). CTR burritos were lighter than TRT burritos with L * values of 80.04 and 64.61, respectively. CTR cookies required a higher breaking force (3.14 compared with 0.58 kg), were lighter than TRT cookies (63.18 compared with 50.27), and had lower water activity (0.5 compared with 0.71).     

季铵型CPAM助留助滤作用的电荷分析

通过胶体滴定法测定了CPAM电荷密度,研究了加填及加入CPAM后浆料悬浮液的电荷变化。结果表明,浆料中加入CaCO3后,浆料的胶体滴定比率(CTR)大幅度降低;随CPAM用量增加浆料的CTR值显著增大,且Zeta电位与logCTR之间存在一定的相关性。     

电荷测量技术用于阳离子淀粉对脱墨浆助留的研究

应用Zeta电位和CTR(胶体滴定比率)分析脱墨(旧报纸)浆料体系的电荷分布情况。研究了不同阳离子淀粉用量、pH值、电导率对浆料Zeta电位、CTR和单程留着率的影响。研究表明,浆料的Zeta电位和CTR可以说明实际电荷分布情况且与阳离子淀粉对浆料的助留作用密切相关。     

胶体滴定方法及其研究进展

介绍了胶体滴定方法的原理、滴定步骤以及影响因素,并对其研究进展作了综合介绍。     

Does the dry cow treatment with monensin controlled release capsule affect Parmigiano Reggiano cheese production?

We investigated the effects of monensin controlled-release capsule (CRC; Kexxtone, Eli Lilly and Company Ltd., Indianapolis, IN) preventative ketosis treatment on the traditional cheesemaking process as well as the final characteristics of Parmigiano Reggiano (PR) cheese. The use of this prevention product to reduce the incidence of ketosis in transition dairy cows was approved by the European Medicines Agency in 2013. No previous studies are available concerning the effects of this treatment on prolonged-ripening cheese production such as PR. In PR cheese production, feed, feed additives, and cow treatments are strictly regulated to avoid any possible interference with traditional manufacturing processes. For these reasons, on 1 farm where all milk was used for PR cheese production, monensin CRC was administered to 33 cows, 21 d before calving in the monensin-treated group (TRT), whereas untreated cows with similar breed and parity characteristics constituted the control group (CTR). For 20 wk, milk obtained from each group and whey starter were separately managed and transported in the cheese factory, where 2 cheese wheels per group were produced daily, making 552 PR cheese wheels in total. Morning bulk tank milk composition, cheesemaking properties, and whey starter fermentation activities were analyzed twice a week. Every aspect of the cheesemaking process was recorded and the resulting cheese was evaluated after 36 h and 6, 12, and 18 mo from production for yield, texture defects, composition, and fatty acids profile. Milk from the 2 groups differed for somatic cell content (TRT = 3.04 vs. CTR = 4.06, somatic cell score), total bacterial count (TRT = 4.08 vs. CTR = 6.08 × 1,000 cfu/mL), titratable acidity (TRT = 3.66 vs. CTR = 3.72 Soxhlet-Henkel degrees/50 mL), and casein content percentage (TRT = 2.4 vs. CTR = 2.5%). Whey starter parameters were comparable between the 2 groups. Final cheese composition and organoleptic profile were not influenced by the treatment, except for C18:1 content being enhanced (TRT = 22.8 vs. CTR = 20.8% of fatty acids). Percentage of defected ripened cheese was significantly lower in the treated group, both at x-ray evaluation performed at 6 mo (TRT = 6.2 vs. CTR = 12.3%) and at the consortium inspection, performed at 12 mo of ripening (TRT = 1.5 vs. CTR = 6.5%). On the other hand, average cheese yield at 18 mo of ripening was partially reduced (TRT = 7.5 vs. CTR = 7.7%). Overall, the use of monensin CRC had no negative effect on the cheesemaking process, prolonged ripening cheese characteristics, milk composition, or whey starter quality.     

Effect of metaphylactic administration of tildipirosin on the incidence of pneumonia and otitis and on the upper respiratory tract and fecal microbiome of preweaning Holstein calves

The objectives of this study were to evaluate the effect of the metaphylactic use of a semi-synthetic long-acting macrolide (tildipirosin) on the prevention of pneumonia and otitis in preweaning Holstein calves, as well as its effects on the microbiome of their upper respiratory tract (URT) and feces. Newborn healthy Holstein heifers, collectively housed, were randomly allocated to 1 of 2 treatment groups: treatment (TRT; n = 932) or control (CTR; n = 927). Calves in the TRT group received a single subcutaneous injection of 4 mg/kg tildipirosin (Zuprevo, Merck Animal Health) at 7 ± 7 d of life. Calves in the CTR group received no drug injection. All enrolled calves were evaluated from 1 to 63 ± 3 d of life (weaning age) and monitored daily for any adverse health events during this period. Daily physical examination was performed to diagnose pneumonia and otitis, and body weight was measured weekly in all animals. From a randomly selected subset of 217 calves, blood samples for biochemical variables analysis and swabs were collected weekly from the URT and rectum for analysis of the nasal and fecal microbiome, respectively, via next-generation sequencing of the 16S rRNA gene. Total bacterial load was evaluated using quantitative PCR. In addition, another subset of 26 calves was randomly selected and fecal swabs were collected in a more intensive sampling to investigate the short-term effect of tildipirosin administration on the fecal microbiome. We performed general mixed linear models and logistic regression to analyze continuous and binary outcomes, respectively. Tildipirosin metaphylaxis reduced the incidence of otitis (CTR = 47.03%; TRT = 37.55%) and tended to reduce the incidence of pneumonia (CTR = 20.71%; TRT = 17.38%) and the overall mortality risk (CTR = 6.69%; TRT = 4.94%). We observed no significant differences between groups for mortality due to pneumonia (CTR = 0.86%; TRT = 0.97%) or mortality due to otitis (CTR = 2.05%; TRT = 1.39%). Calves in the TRT group had a higher average daily gain than calves in the CTR group. Furthermore, metaphylaxis had no significant effects on the total bacterial load, genus, or phylum analysis of the fecal microbiome from the 2 subset groups. However, for the URT microbiota, we observed a significant decrease in total bacterial load for the TRT group compared to the CTR group 1 week after metaphylactic injection. Tildipirosin metaphylaxis decreased the mean relative abundance of the genera Mannheimia, Moraxella, and Pasteurella but significantly increased the mean relative abundance of Mycoplasma. Although tildipirosin had no positive effect on Mycoplasma, it reduced the mean relative abundance of important pathogenic bacteria in the URT and had positive effects for the control of otitis. The metaphylactic use of tildipirosin can be a suitable strategy for the control of otitis on farms with a high prevalence of this disease.     

Immunometabolic status and productive performance differences between periparturient Simmental and Holstein dairy cows in response to pegbovigrastim

In the present study, we aimed to investigate the side effects of pegbovigrastim, injected approximately 7 d before parturition and on the day of calving, on a panel of plasma biomarkers to evaluate energy, inflammatory, oxidative, and liver function status. We also addressed treatment responses in different breeds during the transition period. Holstein and Simmental cows were randomly assigned into 2 groups based on expected calving date and according to parity: the treated group (PEG; 14 Holstein and 12 Simmental cows) received pegylated recombinant bovine granulocyte colony stimulating factor (pegbovigrastim, Imrestor; Elanco Animal Health, Greenfield, IN), and the control group (CTR; 14 Holstein and 14 Simmental cows) received saline solution. The PEG or CTR treatments were administered via subcutaneous injection in the scapular region at approximately 7 d (mean 7.80 ± 5.50 d) before expected parturition and within 24 h after calving. Blood samples were collected at ?21, ?7 (before injection), 1, 3, and 28 d relative to calving. Milk production was recorded at 7, 15, 21, 30, and 42 d. A mixed model with repeated measures was fitted to the normalized data using Proc MIXED of SAS (SAS Institute Inc., Cary, NC). Simmental PEG cows showed higher plasma protein concentrations at 1 and 3 d after calving compared with Simmental CTR and Holstein PEG cows, whereas no differences were detected between Holstein PEG and CTR cows. Albumin was greater at 1 d in Simmental PEG compared with Simmental CTR cows. In contrast, γ-glutamyl transferase was higher overall (across breed) in PEG than in CTR. The PEG group had higher values throughout the postcalving period compared with CTR. Cows treated with pegbovigrastim had also higher alkaline phosphatase (ALP) activity at 1 and 3 d after calving. The Holstein PEG group had higher ALP activity at 3 d compared with the Holstein CTR and Simmental PEG groups, and higher ALP at 1 d compared with the Simmental CTR group. The PEG group had higher levels of IL-6 at 3 and 28 d but higher IL-1β only at 28 d after calving compared with the CTR group. Overall, Holstein cows were characterized by a greater response in the production of inflammation biomarkers (cytokines, haptoglobin, and ceruloplasmin). In addition, PEG cows had higher values of zinc at 1 and 3 d after calving compared with CTR cows. The response observed in plasma biomarkers for energy metabolism and liver functionality after pegbovigrastim treatment in Simmental and Holstein cows was not different from that in control cows. However, our data shed light on the different metabolic adaptations during the transition period between Simmental and Holstein cows, characterized by different energy, inflammatory, and oxidative pattern responses. For the first time, we have highlighted the effect of pegbovigrastim in maintaining stable cytokine levels during the first month after parturition, reflecting greater regulation of neutrophil recruitment, trafficking, and maturation during the inflammatory response. These results provide evidence of the immunomodulatory action of pegbovigrastim around parturition, when dairy cows are highly immunosuppressed. At the same time, these data demonstrate that increasing release of cytokines after parturition is not linked to exacerbation of a systemic inflammation evaluated based on haptoglobin and ceruloplasmin levels.