Western Canadian dairy farmers' perspectives on the provision of outdoor access for dairy cows and on the perceptions of other stakeholders

The provision of pasture and outdoor access for dairy cattle differs around the globe. For example, in Ireland, New Zealand, and Australia, dairy farms are largely pasture based, whereas dairy farms in the United States and Canada are largely confinement based. There is a high level of public support for pasture and outdoor access for dairy cows, and the available evidence shows that dairy cattle are highly motivated to access pasture, especially at night. The decision as to whether to provide outdoor access is typically made by farmers, but little is known about dairy farmers' perspectives on this topic. We investigated perspectives of Western Canadian dairy farmers on outdoor access, as well as how they believe different stakeholders (i.e., the dairy industry, the dairy cows, and the general public) regard outdoor access for dairy cows. Data were collected via (1) 11 focus group discussions with a total of 50 Western Canadian dairy farmers, and (2) semi-structured individual interviews with an additional 6 dairy farmers of Hutterite colonies. Data were analyzed using template analysis. Although most participants in this study did not provide outdoor access on their farms, or only provided outdoor access to certain cow groups, participants generally mentioned that they enjoyed seeing cows on pasture or outdoors. However, participants shared that the Canadian supply management system (including processors) required a consistent flow of production, which was thought to be easier and more economically realized with indoor housing of lactating cows. Participants believed that pasture or outdoor access for dairy cows was desired by the public. Some participants believed that dairy cows prefer to spend time outside under favorable weather conditions, but others felt that cows preferred to stay indoors in modern, ventilated freestall barns. The results of this study describe the perspectives of dairy farmers regarding the views of dairy industry stakeholders as they relate to outdoor access, helping to inform conversations around the provision of outdoor access for dairy cattle.     

Understanding enhancing mechanism of Pr6O11 and Pr(OH)3 in methanol electrooxidation

The presence of oxygen vacancies and hydroxyl groups are both favorable for the methanol electrooxidation on Pt-based catalysts.Understanding and differentiating the enhancing mechanism between oxygen vacancies and hydroxyl groups for high activity of Pt catalysts in methanol oxidation reaction(MOR)is essential but still challenging.Herein,we developed two kinds of co-catalyst for Pt/CNTs,Pr₆O₁₁is rich in oxygen vacancies but contains substantially no hydroxyl groups,while Pr(OH)₃ possesses abundant hydroxyl groups without oxygen vacancies.After a seque nce of designed experiments,it can be found that both oxygen vacancies and hydroxyl groups can improve the performance of Pt/CNTs electrocatalysts,but the enhancing mechanism and improving degree of oxygen vacancies and hydroxyl groups for the MOR are different.Since the oxygen vacancies are more conducive to increasing the intrinsic activity of the Pt catalyst,and the hydroxyl groups play a decisive role in dehydrogenation and deproto nation of methanol,the co-catalysts with both oxygen vacancies and hydroxyl groups mixed with Pt/CNTs have higher catalytic performance.Therefore,hydroxyl-rich Pr₆O₁₁·xH₂O was prepared and used as MOR electrocatalyst after mixed with Pt/CNTs.Benefiting from the synergistic effect of oxygen vacancies and hydroxyl groups,the Pr₆O₁₁·xH₂O/Pt/CNTs shows a high peak current density of 741 mA/mg,which is three times higher than that of Pt/CNTs.These new discoveries serve as a promising strategy for the rational design of MOR catalysts with low cost and high activity.     

Enhancing the Photovoltaic Performance of Ladder-Type Heteroheptacene-based Nonfullerene Acceptors by Incorporating Halogen Atoms on Their Ending Groups

Ending group halogenation is an effective strategy for modulating the energy levels, bandgaps, and intermolecular interactions of nonfullerene acceptors. Understanding the influence of different halogen atoms on the acceptor properties is of great importance for designing high-performance nonfullerene acceptors. Here, three acceptor–donor–acceptor (A-D-A) type nonfullerene acceptors (M5, M6, and M7), which are constructed by using a ladder-type heteroheptacene core without the traditional sp³ carbon-bonded side chains as the electron-rich core, and 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile without or with halogen atoms as the ending groups. The nonfullerene acceptors with chlorinated (M6) and brominated (M7) ending groups exhibit broadened absorption spectra, down-shifted energy levels, and enhanced molecular ordering compared to the counterpart without any halogenated ending groups (M5). Among the nonfullerene acceptors, M6 has the strongest intermolecular π π interaction with its shortest π π interaction distance and the longest coherent length which are beneficial for enhancing the charge transport and therefore boosting the photovoltaic performance. An excellent power conversion efficiency of 15.45% is achieved for the best-performing polymer solar cell based on M6. These results suggest that the halogenated ending groups are essential for high-performance heteroheptacene-based nonfullerene acceptors considering their simultaneous enhancements in both the light-harvesting and the charge transport.     

产教融合背景下高职特色专业群“平台+模块”课程体系建设研究

In view of the problems in the construction of characteristic professional groups in higher vocational colleges, the professional group of "intelligent manufacturing" is taken as the research object, and the "platform + module" suitable for the development of the industry will be constructed according to the content of the vocational ability planning courses of the post group. The curriculum system establishes the framework of professional groups, and explores and forms a strategic study to optimize and integrate professional group resources.     

纳米微晶纤维素的表面基团及其改性

纳米微晶纤维素(Nanocrystalline Cellulose,NCC)是一种纤维素经酸水解后获得的棒状晶体,由于其原料丰富、可再生、生物兼容性好以及机械性能优良等特点,已成为纳米材料研究领域的热点。本文为探索其进一步改性应用,重点分析了NCC表面存在的基团种类,对其化学改性方法进行了概括,并对其进一步发展应用进行了展望。     

Recent Advances in Late-Stage Construction of Stapled Peptides via C−H Activation

Stapled peptides have been widely applied in many fields, including pharmaceutical chemistry, diagnostic reagents, and materials science. However, most traditional stapled peptide preparation methods rely on prefunctionalizations, which limit the diversity of stapled peptides. Recently, the emergence of late-stage transition metal-catalyzed C−H activation in amino acids and peptides has attracted wide interest due to its robustness and applicability for peptide stapling. In this review, we summarize the methods for late-stage construction of stapled peptides via transition metal-catalyzed C−H activation.     

Technical note: Genetic groups in single-step single nucleotide polymorphism best linear unbiased predictor

Genetic groups, also called unknown or phantom parents groups, are often used in dairy cattle genetic evaluations to account for selection that cannot be accounted for by known genetic relationships. With the advent of genomic evaluations, the theory of genetic groups was extended to the so-called single-step genomic BLUP (ssGBLUP). In short, genetic groups can be fitted in ssGBLUP through regression effects, or by including them in the pedigree and computing the adequate combined pedigree and genomic relationship matrix. In this study, we applied the so-called Quaas and Pollak transformation to a system of equations for single-step SNP BLUP (ssSNPBLUP), such that genetic groups can thereafter be included in the pedigree. The example in this study showed that including the genetic groups in the pedigree for ssSNPBLUP allowed reduced memory burden and computational costs in comparison to genetic groups fitted as covariates.     

Exploring the Selective Demethylation of Aryl Methyl Ethers with a Pseudomonas Rieske Monooxygenase

Biocatalytic dealkylation of aryl methyl ethers is an attractive reaction for valorization of lignin components, as well as for deprotection of hydroxy functionalities in synthetic chemistry. We explored the demethylation of various aryl methyl ethers by using an oxidative demethylase from Pseudomonas sp. HR199. The Rieske monooxygenase VanA and its partner electron transfer protein VanB were recombinantly coexpressed in Escherichia coli and they constituted at least 25 % of the total protein content. Enzymatic transformations showed that VanB accepts NADH and NADPH as electron donors. The VanA–VanB system demethylates a number of aromatic substrates, the presence of a carboxylic acid moiety is essential, and the catalysis occurs selectively at the meta position to this carboxylic acid in the aromatic ring. The reaction is inhibited by the by-product formaldehyde. Therefore, we tested three different cascade/tandem reactions for cofactor regeneration and formaldehyde elimination; in particular, conversion was improved by addition of formaldehyde dehydrogenase and formate dehydrogenase. Finally, the biocatalyst was applied for the preparation of protocatechuic acid from vanillic acid, giving a 77 % yield of the desired product. The described reaction may find application in the conversion of lignin components into diverse hydroxyaromatic building blocks and generally offers potential for new, mild methods for efficient unmasking of phenols.     

加权评分法和Friedman检验法对4种香肠制品的感官评价

目的分析4个不同工艺的香肠制品的感官总评分与每个感官因子评分之间的关系,明确总评分顺序不能代表每个感官指标的顺序。方法根据文献选择4个描述香肠的感官描述词:色泽、风味、质地和咀嚼性。10个经验型感官评价员用0～4法计算色泽、风味、质地、咀嚼性4个因子的权重值,再根据4个权重值计算4个品牌香肠的加权总评分。用非参数Friedman检验法分析4个品牌香肠加权总评分之间的统计学差异。再用多重比较和分组法检验不同品牌香肠4个感官因子色泽、风味、质地和咀嚼性两两之间的统计学差异。结果色泽、风味、质地和咀嚼性的权重值分别是0.238、0.304、0.200和0.258,加权评分的结果是品牌2品牌4品牌1品牌3, Friedman法检验4个品牌香肠加权总评分统计学上有差异(a=0.01)。进一步采用多重分组和比较可以看出,色泽感官因子,香肠品牌1、2、3、4之间统计学上都有差异(α=0.05)。风味感官因子品牌3与品牌1、2统计学有差异(α=0.05),质地感官因子品牌4与品牌3、2之间统计学上有差异(α=0.05),咀嚼性感官因子品牌2与品牌4、1之间有统计学差异(α=0.05)。结论在不同工艺制作的香肠制品中,评价员对香肠的综合评分顺序和差异性不能代表每个感官因子的感官评价顺序和差异,这就要求香肠生产企业更加关注每个感官指标对整体评分的影响。     

准东煤焦的微波放电特性

通过微波辐照准东煤焦，研究了炭化温度、粒径、微波功率和负压对煤焦放电的影响，利用FT-IR技术测定了微波放电对煤焦表面官能团的影响。结果表明:常压下，600 ℃以下炭化的煤焦经微波加热到200~300 ℃才会放电;800 ℃以上炭化的煤焦，炭化温度越高，整体放电越弱，终温越低;大粒径煤焦为间歇性弧光放电，小粒径煤焦为间歇性星点放电;煤焦粒径越小，放电时热点越多，煤焦终温越高;煤焦粒径小于98 μm时不放电;功率越高，煤焦整体放电越强;负压可促进煤焦放电，导致煤焦终温升高，达到临界负压，煤焦颗粒难以出现放电火花而温度急剧下降;放电可以促进煤焦芳环的开链和加速脂肪结构、含氧类官能团的转化脱除。