A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate.Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface density.Here,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios.Stable porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL 5k.As a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was assessed.After two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor II(BMPRII)on films with the conjugated peptide.In addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface density.Taken together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface.Moreover,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(modified)polymers.Furthermore,the use of alkyne-azide“click”chemistry enables spatial control over bioconjugation of many tissue-specific moieties,making this approach a versatile strategy for tissue engineering applications.

The biological functions and metabolic pathways of valine in swine

Valine is an essential amino acid and a type of branched-chain amino acid. Due to the involvement of branchedchain amino acids in various metabolic pathways, there has been a surge of interests in valine nutrition and its role in animal physiology. In pigs, the interactions between valine and other branched-chain amino acids or aromatic amino acids are complex. In this review, we delve into the interaction mechanism, metabolic pathways, and biological functions of valine. Appropriate valine supplementation not only enhances growth and reproductive performances, but also modulates gut microbiota and immune functions. Based on past observations and interpretations, we provide recommended feed levels of valine for weaned piglets, growing pigs, gilts, lactating sows, barrows and entire males. The summarized valine nutrient requirements for pigs at different stages offer valuable insights for future research and practical applications in animal husbandry.

On the Differentiability of Vector Valued Additive Set Functions

The Lebesgue-Nikodym Theorem states that for a Lebesgue measure an additive set function ?which is -absolutely continuous is the integral of a Lebegsue integrable a measurable function;that is, for all measurable sets.?Such a property is not shared by vector valued set functions. We introduce a suitable definition of the integral that will extend the above property to the vector valued case in its full generality. We also discuss a further extension of the Fundamental Theorem of Calculus for additive set functions with values in an infinite dimensional normed space.

Review of functionally graded materials processed by additive manufacturing

Additive manufacturing(AM)technology makes parts through layer-by-layer deposition,which can regulate the microstructure and properties of different parts of a single part well.It provides a new idea for the preparation of functionally gradient materials(FGM),and has become a research hotspot at present.By referring to and analyzing the recent research achievements in the additive manufacturing tech-nology of FGM,the latest research progress at domestic and abroad from four aspects were summaried:selective laser melting additive man-ufacturing,electron beam additive manufacturing,arc additive manufacturing,path planning,and material texture.Moreover,the existing problems in the research are pointed out,and the future research direction and focus are prospected.

Effects of Chinese Herbal Additive on Immunologic Functions and Productive Performance of Dairy Cows during Heat Stress

[Objective] To study effects of Chinese herbal additive on immunologic functions and productive performance of dairy cows, [Method] A total of 20 healthy dairy cows were randomly divided into control group and experimental group. They were respectively fed a common basal diet and the basal diet containing 100 g Chinese herbal additives. The trial lasted for 49 d. [ Result] The 4% fat corrected milk yield （FCM） production, milk yield after weight correction, quantity of solid-not-fat and ash content in the experimental group were significantly higher than those in the control group （ P 〈 0.01 ）. The total lymphocytes （LYM） number of peripheral blood, the percentage of lymphocytes, and IgG concentration in the experimental group were significantly higher than those in the control group on Day 14, 28 and 42 （ P 〈 0.01 ）. [ Conclusion] The Chinese herbal additive can enhance the lactation performance and immunologic function of dairy cows.

Towards additive manufacturing oriented geometric modeling using implicit functions

Surface-based geometric modeling has many advantages in terms of visualization and traditional subtractive manufacturing using computer-numerical-control cutting-machine tools.However,it is not an ideal solution for additive manufacturing because to digitally print a surface-represented geometric object using a certain additive manufacturing technology,the object has to be converted into a solid representation.However,converting a known surface-based geometric representation into a printable representation is essentially a redesign process,and this is especially the case,when its interior material structure needs to be considered.To specify a 3D geometric object that is ready to be digitally manufactured,its representation has to be in a certain volumetric form.In this research,we show how some of the difficulties experienced in additive manufacturing can be easily solved by using implicitly represented geometric objects.Like surface-based geometric representation is subtractive manufacturing-friendly,implicitly described geometric objects are additive manufacturing-friendly:implicit shapes are 3D printing ready.The implicit geometric representation allows to combine a geometric shape,material colors,an interior material structure,and other required attributes in one single description as a set of implicit functions,and no conversion is needed.In addition,as implicit objects are typically specified procedurally,very little data is used in their specifications,which makes them particularly useful for design and visualization with modern cloud-based mobile devices,which usually do not have very big storage spaces.Finally,implicit modeling is a design procedure that is parallel computing-friendly,as the design of a complex geometric object can be divided into a set of simple shape-designing tasks,owing to the availability of shape-preserving implicit blending operations.

The Additive Generators of <i>n</i>-Dimensional Overlap Functions

In this paper, we introduce the concepts of additive generators and additive generator pair of n-dimensional overlap functions, in order to extend the dimensionality of overlap functions from 2 to n. We mainly discuss the conditions under which an n-dimensional overlap function can be expressed in terms of its generator pair.

Robust Frequency Estimation Under Additive Symmetric α-Stable Gaussian Mixture Noise

Here the estimating problem of a single sinusoidal signal in the additive symmetricα-stable Gaussian(ASαSG)noise is investigated.The ASαSG noise here is expressed as the additive of a Gaussian noise and a symmetricα-stable distributed variable.As the probability density function(PDF)of the ASαSG is complicated,traditional estimators cannot provide optimum estimates.Based on the Metropolis-Hastings(M-H)sampling scheme,a robust frequency estimator is proposed for ASαSG noise.Moreover,to accelerate the convergence rate of the developed algorithm,a new criterion of reconstructing the proposal covar-iance is derived,whose main idea is updating the proposal variance using several previous samples drawn in each iteration.The approximation PDF of the ASαSG noise,which is referred to the weighted sum of a Voigt function and a Gaussian PDF,is also employed to reduce the computational complexity.The computer simulations show that the performance of our method is better than the maximum likelihood and the lp-norm estimators.

中草药添加剂对西门塔尔肉牛血清免疫、细胞因子、抗氧化指标及直肠菌群的影响

试验旨在研究饲粮中添加中草药添加剂对西门塔尔肉牛血清免疫、细胞因子、抗氧化指标及直肠菌群的影响。采用单因素随机区组试验设计,选取20头健康的12月龄平均体重为(268.80±4.95)kg的西门塔尔肉牛,随机分为对照组(CG组)和试验组(AG组),每组10个重复,每个重复1头肉牛。CG组饲喂基础饲粮,AG组在基础饲粮中额外添加100 g/(头·d)中草药添加剂。预试期5 d,正式试验期60 d。结果表明:与CG组相比,AG组西门塔尔肉牛血清免疫球蛋白A(IgA)和白细胞介素-6(IL-6)含量提高了12.70%和7.58%(P<0.05),血清总超氧化物歧化酶(T-SOD)活性提高了3.13%(P<0.05),丙二醛(MDA)含量降低了28.87%(P<0.05),总抗氧化能力(T-AOC)提高了1.39%(P>0.05)。AG组西门塔尔肉牛肠道菌群Shannon、Chao1和Ace指数比CG组分别提高了0.17%、1.51%和0.96%(P>0.05)。AG组西门塔尔肉牛肠道中拟杆菌门(Bacteroidetes)和疣微杆菌门(Verrucomicrobia)的相对丰度比CG组提高了6.50%和2.94%(P>0.05),厚壁菌门(Firmicutes)的相对丰度比CG组降低了5.94%(P>0.05);未分类拟杆菌属(unclassified_Bacteroidetes)的相对丰度高于CG组(P<0.05),居海事城球杆菌属(Phocaeicola)和另枝菌属(Alistipes)的相对丰度比CG组提高了8.33%和16.45%(P>0.05)。研究表明,中草药添加剂可以提高西门塔尔肉牛的免疫水平、抗氧化能力、肠道菌群丰度,促进肠道有益菌群的生长,增强机体消化纤维的能力。

基于非稳态加性噪声模型的因果发现算法

因果发现旨在通过观测数据挖掘变量间的因果关系。现有的因果发现方法大多假定数据的产生过程是平稳的,然而在实际环境下往往不满足稳态假设,导致结果不可靠。研究发现,在一些场景中的非稳态扰动与时序信息高度相关。因此,在加性噪声模型基础上将非稳态扰动刻画为一项关于时序信息的函数,设计非稳态加性噪声模型,并给出非稳态加性噪声模型的识别条件,提出一种两阶段的因果关系学习算法。第1阶段利用回归计算得到变量残差,再检验残差与回归特征集的独立性从而选出叶子节点,迭代得到观测变量集的因果次序;第2阶段再次进行回归计算和独立性检验,消除第1阶段中冗余的因果关系,从而得到观测变量集的因果结构。实验结果表明,与基于约束的异构/非平稳因果发现、LPCMCI和Ti MINo算法相比,该算法在仿真数据集上取得了最优的效果,平均F1值达到0.85;而在真实因果结构数据集中,该算法的F1值平均提升41.12%,能够从非稳态数据集中恢复出更多因果结构的信息。

哈密瓜物流堆码运输包装件共振传递特性研究

为优化设计缓冲包装件,以及减缓运输过程中由共振引起的哈密瓜贮藏品质下降,采用哈密瓜及其包装瓦楞纸箱作为研究对象,设置5层堆码高度,进行模拟运输变频振动试验,结合频谱分析加汉宁窗函数测定各堆码包装件的固有频率,随后进行模拟运输定频振动试验。结果表明,加汉宁窗函数有效提高了频谱分析精度,获得5层包装件的固有频率分别为9.88,54.75,10.06,10.31,10.42 Hz;10 Hz定频振动下,5层包装件的峰值加速度分别为5.99,3.18,6.37,6.56,6.81 g,振动传递率分别为53.61%,28.52%,57.07%,58.76%,61.02%;54.75 Hz定频振动下,5层包装件的峰值加速度分别为1.29,6.34,0.99,0.87,0.23 g,振动传递率分别为8.38%,45.04%,6.47%,6.04%,0.75%。研究为其他包装件寻求更精确的共振频率,从而为运输过程中有效避开共振频率,达到内装果品减损目的提供参考。

探讨额外侧锁孔入路与翼点入路夹闭术在前交通动脉瘤的应用效果

目的探讨于前交通动脉瘤中分别应用额外侧锁孔入路和翼点入路夹闭术的临床效果。方法回顾性选择2020年3月-2023年5月邳州市中医院行开颅动脉瘤夹闭手术的62例前交通动脉瘤破裂患者的临床资料,根据手术入路方式将其分为对照组(n=31)和观察组(n=31)。对照组行翼点入路开颅治疗,观察组行额外侧锁孔入路开颅治疗。比较两组手术情况、术后日常生活能力、神经及认知功能改善程度,统计两组并发症发生情况。结果治疗后,观察组患者的术中出血量(260.16±75.27)mL少于对照组,手术时间(206.78±28.07)min及住院时间(7.34±1.84)d均短于对照组,差异有统计学意义(t=7.578、7.405、7.404,P均<0.05);观察组术中动脉瘤破裂出血率、脑直回切除率均比对照组低,观察组神经功能缺损评分、日常生活能力评分优于对照组,观察组认知功能评分高于对照组,差异有统计学意义(P均<0.05);治疗后,两组患者出现术后新增颅内出血、短暂性缺血、感染、神经症状及脑积水等并发症的总发生率比较,差异无统计学意义(P>0.05)。结论前交通动脉瘤患者分别接受额外侧锁孔入路术和翼点入路夹闭术治疗均具有一定效果,但额外侧锁孔入路术的效果更理想,在改善神经及认知功能、日常生活能力方面存在显著优势,且不会产生严重并发症。

阴道骶棘韧带悬吊术治疗盆腔脏器脱垂的临床效果及术后并发症观察

目的探讨阴道骶棘韧带悬吊术(SSLF)治疗盆腔器官脱垂(POP)的临床效果及术后并发症发生情况。方法选取2018年1月—2022年2月收治的POP患者68例,采用随机数字表法分为观察组34例和对照组34例,观察组采用阴道子宫切除联合SSLF治疗,对照组采用阴道子宫切除联合阴道前或后壁修补术治疗。比较2组手术时间、术中出血量、术后住院时间,手术前后盆底功能障碍问卷(PFDI-20)、盆底障碍影响简易问卷-7(PFIQ-7)评分,以及术后并发症发生率。结果观察组手术时间及术后住院时间均较对照组缩短,术中出血量也较对照组显著减少(P<0.01)。2组患者术前盆腔器官脱垂定量分度法(POP-Q)各指示点测量值均无显著差异(P>0.05);与术前POP-Q各指示点测量值相比,2组患者术后测量值均明显降低,其中观察组测量值更低(P<0.05)。术前PFDI-20、PFIQ-7评分2组患者均无显著差异(P>0.05);术后2组患者PFDI-20、PFIQ-7评分均明显下降,其中观察组下降更明显(P<0.05)。观察组术后并发症发生率为5.88%(2/34)低于对照组的26.47%(9/34),差异有统计学意义(P<0.05)。结论SSLF治疗POP临床效果显著,能显著改善患者盆底功能,且术后并发症发生率较低。

荒漠草原植物在氮磷添加下叶功能性状特征及其可塑性

探究荒漠草原植物在N、P添加下叶功能性状特征及其变异,对揭示植被对环境的响应机制至关重要。以宁夏盐池县荒漠草原植物群落为研究对象,分析了N、P添加对植物群落叶片形态和化学性状的影响。结果表明:植物群落叶片氮磷比<14,表明研究区植物生长受到N限制,P添加对植物群落叶片功能性状无显著影响,N+P共同添加显著增加了叶片碳磷比,N添加下植物群落叶面积、比叶面积、叶组织密度和叶片氮含量显著上升,反映了植物在环境的变化下采取了较快的养分循环策略;根据可塑性指数排序结果可知,植物群落叶面积、比叶面积、叶片干物质含量、叶组织密度、叶片碳含量和叶片氮含量为响应N、P添加的敏感性状(PI>0.5),其中变异性较大的性状为叶面积、比叶面积和叶组织密度,表明植物群落主要通过改变自身形态来应对环境的变化;相关性分析结果表明,植物群落叶片性状之间存在显著的相关性,并且表现出应对养分环境变化的协同作用。本研究为预测植物和生态系统对全球变化因素的反应提供了理论依据,对探讨区域植被分布、恢复进程至关重要。

聚乙醇酸加工技术中助剂的应用进展

综述了聚乙醇酸(PGA)加工技术中助剂的应用进展,包括抗氧剂、扩链剂、抗水解剂以及无机粒子。

语义通信的数学理论

自从1948年经典信息论诞生以来,在其指导下,现代通信技术已经逼近了理论性能极限,例如信息熵H(U)、信道容量C=max_(p(x))I(X;Y)以及率失真函数R(D)=min_(p(x|x):Ed(x,x)≤D)I(X;X)。长期以来,由于经典信息论只研究语法信息,限制了通信科学的进一步发展。近年来,研究语义信息处理与传输的通信技术获得了学术界的普遍关注,语义通信开辟了未来通信技术发展的新方向,但还缺乏一般性的数学指导理论。为了解决这一难题,构建了语义信息论的理论框架,对语义信息的度量体系与语义通信的理论极限进行了系统性阐述。首先,通过深入分析各类信源的数据特征,以及各种下游任务的需求,总结归纳出语义信息的普遍属性——同义性。由此指出语义信息是语法信息的上级概念,是许多等效或相似语法信息的抽象特征,表征隐藏在数据或消息背后的含义或内容。将语义信息与语法信息之间的关系命名为同义映射,这是一种“一对多”映射,即一个语义符号可以由许多不同的语法符号表示。基于同义映射f这一核心概念,引入语义熵H_(s)(U)作为语义信息的基本度量指标,表示为信源概率分布与同义映射的泛函。在此基础上,引入上/下语义互信息I^(s)(X;Y)(I_(s)(X;Y)),语义信道容量C_(s)=max_(f_(xy))max_(p_((x)))I^(s)(X;Y)以及语义率失真函数R_(s)(D)=min_({f_(x),f_(x)})min_(p(x|x):Ed_(s)(x,x)≤D)I_(s)(X;X),从而构建了完整的语义信息度量体系。这些语义信息度量是经典信息度量的自然延伸,都由同义映射约束,如果采用“一对一”映射,则可以退化为传统的信息度量。由此可见,语义信息度量体系包含语法信息度量,前者与后者具有兼容性。其次,证明了3个重要的语义编码定理,以揭示语义通信的性能优势。基于同义映射,引入新的数学工具——语义渐近均分(AEP),详细探讨了同义典型序列的数学性质,并应用随机编码和同义典型序列译码/编码,证明了语义无失真信源编码定理、语义信道编码定理和语义限失真信源编码定理。类似于经典信息论,这些基本编码定理也都是存在性定理,但它们指出了语义通信系统的性能极限,在语义信息论中起着关键作用。由同义映射和这些基本编码定理可以推断,语义通信系统的性能优于经典通信系统,即语义熵小于信息熵H_(s)(U)≤H(U),语义信道容量大于经典信道容量C_(s)≥C,以及语义率失真函数小于经典率失真函数R_(s)(D)≤R(D)。最后,讨论了连续条件下的语义信息度量。此时,同义映射转换为连续随机变量分布区间的划分方式。相应地,划分后的子区间被命名为同义区间,其平均长度定义为同义长度S。特别是对于限带高斯信道,得到了一个新的信道容量公式C_(s)=B log[S^(4)(1+P/N_(0)B)],其中,平均同义长度S表征了信息的辨识能力。这一容量公式是经典信道容量的重要扩展,当S=1时,该公式退化为著名的香农信道容量公式。综上所述,语义信息论依据同义映射这一语义信息的本质特征,构建了语义信息的度量体系,引入新的数学工具,证明了语义编码的基本定理,论证了语义通信系统的性能极限,揭示了未来语义通信的巨大性能潜力。

中草药添加剂对断奶湖羊生长性能、血清抗氧化指标及免疫功能的影响

试验旨在研究不同剂量的中草药添加剂对湖羊生长性能、血清抗氧化指标及免疫功能的影响。选取48只2月龄健康状况良好、体重相近的断奶公羔湖羊,随机分成4组,每组设4个重复。对照组饲喂基础饲粮,试验Ⅰ组、Ⅱ组、Ⅲ组分别在基础饲粮中添加0.010、0.025、0.050 g/kg的中草药添加剂。预试期7 d,正式试验期90 d。结果表明,61~90 d,试验Ⅱ组湖羊平均日增重比对照组增加了22.22%(P<0.05),料重比降低了18.85%(P<0.01)。第30 d,与对照组相比,试验Ⅱ组总蛋白(TP)、干扰素-γ (IFN-γ)含量显著升高(P<0.05)。与试验Ⅲ组相比,试验Ⅱ组免疫球蛋白G (IgG)、白细胞介素4 (IL-4)、白细胞介素6 (IL-6)、肿瘤坏死因子-α(TNF-α)、IFN-γ含量显著或极显著升高(P<0.05或P<0.01)。第60 d,试验Ⅱ组还原型谷胱甘肽(GSH)含量极显著高于对照组及试验Ⅲ组(P<0.01)。与对照组和试验Ⅲ组相比,试验Ⅱ组免疫球蛋白A (IgA)、IgG、IL-4、IFN-γ含量极显著升高(P<0.01),试验Ⅱ组IL-6含量显著高于试验Ⅲ组(P<0.05),IgA、IL-4含量显著或极显著高于试验Ⅰ组(P<0.05或P<0.01)。第90 d,试验Ⅱ组IgA含量极显著高于对照组(P<0.01),免疫球蛋白M(IgM)、IFN-γ含量显著高于试验Ⅲ组(P<0.05)。研究表明,中草药添加剂能够促进湖羊的生长,增强动物机体的抗氧化能力和免疫力,中草药添加剂的适宜添加量为0.025 g/kg。

不同收获期与添加剂处理对甜高粱青贮品质及体外消化率的影响

本试验旨在研究不同收获期与添加剂处理对甜高粱青贮品质及体外消化率的影响。试验以甜高粱为材料,分别在抽穗期、乳熟期和蜡熟期收获,并分别设置对照处理(CK)、布氏乳杆菌处理(LB)、纤维素酶处理(CE)及菌酶联用处理(LB+CE),共12个处理,每个处理3个重复,装填于3 L发酵桶中室温贮藏120 d,测定发酵品质和营养成分含量,并采用主成分分析和隶属函数法综合评价不同收获期与添加剂处理的甜高粱青贮品质。结果表明:收获期与添加剂对甜高粱青贮饲料pH、氨态氮/总氮以及乳酸、乙酸、干物质和中性洗涤纤维含量具有显著交互作用(P<0.05)。与CK相比,CE和LB+CE显著提高抽穗期和乳熟期甜高粱青贮饲料乳酸含量(P<0.05),LB和LB+CE显著提高各收获期乙酸含量(P<0.05),不同添加剂处理均显著提高乳熟期可溶性碳水化合物含量(P<0.05),CE显著降低乳熟期中性洗涤纤维含量(P<0.05)。不同收获期显著影响甜高粱青贮饲料的体外干物质消化率(P<0.05),在蜡熟期收获进行青贮体外干物质消化率最高。主成分分析和隶属函数分析结果表明,甜高粱各收获期综合得分排名为蜡熟期>乳熟期>抽穗期,且在蜡熟期LB+CE隶属函数平均值最高。综上所述,蜡熟期是调制甜高粱青贮饲料的适时收获期,并建议菌酶联用。

恒流充电有限柱体电极浓度分布及扩散诱导应力解析分析

常见的柱状电极模型中,在轴向方向一般采用无限长假设广义平面应变分析方法,本文考虑恒流充电下有限柱形电极模型,基于力-化耦合一般方程,推导出位移与扩散诱导应力解析解.有限柱体电极中浓度分布由仅考虑径向扩散和仅考虑轴向扩散两部分叠加求解.将浓度函数代入力学方程,使用Boussinesq-Papkovich函数得到应力分量解析解.计算了表面自由柱状电极中浓度和应力场,并将其结果与有限元软件计算的结果进行对比计算.结果表明,理论解和数值解中浓度分布一致,应力分量趋势一致数值相差较小,在荷电状态为17.9%时径向应力在中心处相对误差最大约为4%.本文分析了不同长径比柱状电极中径向和轴向单向扩散对应力场的影响,结果表明,随着长径比的增大,轴向扩散对浓度分布影响下降,径向扩散对应力场影响上升.