Molecular dynamics simulation of the flow mechanism of shear-thinning fluids in a microchannel

Shear-thinning fluids have been widely used in microfluidic systems,but their internal flow mechanism is still unclear.Therefore,in this paper,molecular dynamics simulations are used to study the laminar flow of shear-thinning fluid in a microchannel.We validated the feasibility of our simulation method by evaluating the mean square displacement and Reynolds number of the solution layers.The results show that the change rule of the fluid system's velocity profile and interaction energy can reflect the shear-thinning characteristics of the fluids.The velocity profile resembles a top-hat shape,intensifying as the fluid's power law index decreases.The interaction energy between the wall and the fluid decreases gradually with increasing velocity,and a high concentration of non-Newtonian fluid reaches a plateau sooner.Moreover,the velocity profile of the fluid is related to the molecule number density distribution and their values are inversely proportional.By analyzing the radial distribution function,we found that the hydrogen bonds between solute and water molecules weaken with the increase in velocity.This observation offers an explanation for the shear-thinning phenomenon of the non-Newtonian flow from a micro perspective.

博士后对学术职业环境满意吗?——基于Nature全球博士后调查数据比较分析

本研究基于已有成果,将博士后学术职业环境划分为学术资源、职业保障、组织管理、科研强度四个维度。利用2020年Nature全球博士后教育调查数据,通过比较分析博士后对学术职业环境的感知与评价。研究发现,相比较国外发达国家博士后而言,我国接近四成博士后对学术职业环境感到满意。为了优化博士后学术职业环境,大学需强化对博士后科研资金的支持力度,保障博士后科研参与机会,减少非学术事务对博士后科研时间的挤占,规范导师指导;大学不断调适大学基层学术组织治理模式,优化院系对博士后学术职业发展的组织支持与服务质量;大学与博士后建立稳定性雇佣关系,不断提升工资薪酬水平,疏通博士后学术职业晋升渠道,营造良好的工作环境;高校实行服务型、便捷式的科研管理方式,制定灵活多元的学术评价机制,破除博士后对“学术GDP主义”的崇拜。

The Alienation of Nature in Emily Dickinson’s Poems through the Prism of Taoism

In the poems created by the renowned American poet Emily Dickinson,those related to nature constitute a considerable proportion.However,Dickinson’s attitude toward nature is,in fact,contradictory.On the one hand,Dickinson perceives nature as gentle and kind,akin to a mother.Nature is regarded as“heaven”and embodies harmony.On the other hand,nature possesses its own operational principles and harbors inherent cruelty.According to Dickinson,humans should refrain from excessive interference in the natural order.This article attempts to analyze the similarities in attitude towards nature between Dickinson’s poetry and Taoist philosophy.

Problems and Development Suggestions of Nature Education in Jiangxi Province

The forest coverage rate of Jiangxi Province ranks second in China.It has rich natural resources,a long history of ancient color culture and rich red culture.In the development of nature education,Jiangxi Province has great potential and advantages.This paper introduces the development conditions of nature education in Jiangxi Province,summarizes the problems existing in the development of nature education in Jiangxi Province from the aspects of the types of nature education and the construction of nature education base,such as simple content and single form,imperfect infrastructure and lack of professionals,and puts forward some suggestions on the development of nature education in Jiangxi Province.

Adaptive Network Sustainability and Defense Based on Artificial Bees Colony Optimization Algorithm for Nature Inspired Cyber Security

Cyber Defense is becoming a major issue for every organization to keep business continuity intact.The presented paper explores the effectiveness of a meta-heuristic optimization algorithm-Artificial Bees Colony Algorithm(ABC)as an Nature Inspired Cyber Security mechanism to achieve adaptive defense.It experiments on the Denial-Of-Service attack scenarios which involves limiting the traffic flow for each node.Businesses today have adapted their service distribution models to include the use of the Internet,allowing them to effectively manage and interact with their customer data.This shift has created an increased reliance on online services to store vast amounts of confidential customer data,meaning any disruption or outage of these services could be disastrous for the business,leaving them without the knowledge to serve their customers.Adversaries can exploit such an event to gain unauthorized access to the confidential data of the customers.The proposed algorithm utilizes an Adaptive Defense approach to continuously select nodes that could present characteristics of a probable malicious entity.For any changes in network parameters,the cluster of nodes is selected in the prepared solution set as a probable malicious node and the traffic rate with the ratio of packet delivery is managed with respect to the properties of normal nodes to deliver a disaster recovery plan for potential businesses.

《Nature》揭示:禁食机制下的脂肪依赖性肿瘤会消退

近日,一篇发表在《Nature》上的研究显示,研究发现了一种能让小鼠摆脱胰腺癌的新方法,该疗法通过抑制脂肪代谢,切断肿瘤的能量供应,只要小鼠持续遵循生酮饮食,肿瘤生长便会停滞。研究中,研究团队聚焦于机体在禁食状态下如何转向脂肪作为能源的问题。研究者发现直接关联到胰腺癌的生物学研究,首次揭示了真核生物翻译起始因子(eukaryotic translation initiation factor,eIF4E)在禁食期间如何调控机体代谢,使其从消耗碳水化合物转变为消耗脂肪。

《Nature》子刊:苏佳琪等开发基于牛奶的水凝胶,用作酒精中毒的解毒剂

近日,苏黎世联邦理工学院Raffaele Mezzenga、苏佳琪等人在《Nature》子刊《Nature Nanotechnology》上发表的一篇研究显示,该研究开发了一种口服的、基于牛奶蛋白的水凝胶——FeSA@FibBLG,或可作为急性酒精中毒的有效解毒剂,能够稳定耐受胃酸消化且持续显著降低酒精中毒小鼠血液中的酒精水平,同时避免额外积累有毒的乙醛,还可增强肝脏保护,并显著减轻肠道损伤和生态失调,强调了其作为酒精相关疾病的新疗法的潜力。

Nature’s Gift

NATURAL WONDERS IN CHINA AND AFRICA Qilian Mountains National Park Located in Northwest China’s Gansu and Qinghai provinces,Qilian Mountains National Park spans 50,200 square km,serving as a vital ecological security barrier and water source conservation area in west China.Established in 2017 to address ecosystem damage,intensive food chain protection and wildlife monitoring in the area began in early 2011.

Spatiotemporal Evolution of Ecological Quality in Alpine Freshwater Lake Nature Reserves in the Past 20 Years

The Caohai Nature Reserve is one of the three major plateau freshwater lakes in China.Since the 1950s,human activities such as land reclamation and population relocation have greatly damaged Caohai.A rapid evaluation of the spatiotemporal evolution trend of the ecological quality of the Caohai Nature Reserve is significant for the maintenance and construction of the ecosystem in this area.The research is based on the Google Earth Engine(GEE)remote sensing cloud computing platform.Landsat TM/OLI images from May to October in five time periods:2000-2002,2004-2006,2009-2011,2014-2016,and 2019-2021 were obtained to reconstruct the optimal cloud image set by averaging the images in each time period.By constructing four ecological indicators:Greenness(NDVI),Wetness(Wet),Hotness(LST),and Dryness(NDBSI),and using Principal Component Analysis(PCA)method to obtain the Remote Sensing Ecological Index(RSEI)for the corresponding years,the spatiotemporal variation of ecological quality in the Caohai Nature Reserve over 20 years was analyzed.The results indicate:①the mean value of RSEI increased from 0.460 in 2000-2002 to 0.772 in 2019-2021,a 67.83%increase,indicating a significant improvement in the ecological quality of the reserve over the 20 years;②from the perspective of functional zoning of the Caohai Nature Reserve,the ecological quality of the core area showed a degrading trend,while the ecological quality of the buffer zone and experimental zone significantly improved;③with the implementation of ecological restoration projects,the ecological quality of the reserve gradually recovered and improved from 2014 to 2021.The trend of RSEI value changes is well correlated with human interventions,indicating that the PCA-based RSEI model can be effectively used for ecological quality assessment in lake areas.

《Nature》:新开发的可穿戴超声贴片可连续、无创监测大脑血流

近日,一篇发表在《Nature》上的研究显示,研究人员开发出一种可穿戴超声贴片(wearable ultrasound patch),其可对大脑血流进行连续、无创的监测。该研究将贴片在36名健康志愿者身上进行了测试,以检验其测量脑部主要动脉血流速度(收缩期峰值、平均流速和舒张末期速度)的能力,发现测量结果与传统超声探头的测量结果非常吻合。

《Nature》:科学家发现能驱动患者狼疮发生的两种细胞缺陷

近日,一篇发表在《Nature》上的研究显示,研究发现了一种特殊的分子缺陷或会促进系统性红斑狼疮的病理性免疫反应,同时揭示了逆转这一缺陷或有望逆转疾病。该研究中,研究人员报道了驱动狼疮发生的新通路,研究者表示,患者体内血液中的多种分子都会发生疾病相关的改变,最终,这些变化会导致芳香烃受体(aryl hydrocarbon receptor,AHR)所控制的通路激活不足,AHR能调节细胞对环境污染物、细菌或代谢产物的反应。

“Eternal Motion” as a “Form of Movement of a Special Nature” and the Main Condition for the Creation of the Universe

The article hypothesizes that DE and DM (UCM) are a “Form of Motion of a Special Nature”, where “Form of Motion” means “Eternal Motion” as the power of dynamics of different levels and varying degrees of self-sufficiency, and by “Special Nature”, gravitational and two other properties of matter, “tied” to the “Eternal Movement” and completely dependent on it. Carriers of key properties of a “Special Nature” have been established: “0”-DE particles and “3”-DM particles (UDM). The unity of their inherent “motionally-gravitational” properties and the peculiarity of the relationship between “motion” and “gravity” are revealed: the higher the intensity of “Eternal Motion”, the stronger the gravitational properties of matter are manifested (and vice versa). The relationship of “time” with the “vibration frequency” and the “mass” of photons with the “degree of bonding and deformation properties of the field” is shown. The maximum level of gravity has been determined, which allows Nature to successfully create the Universe: such a landmark is the proximity to the property of the Primary Source—the “pure graviton” of the OSP space, the most powerful “motionally-gravitational” particle of the Universe. The reasons for the emergence of such an identity of the gravitational properties of particles with the indicators of a “pure graviton” are established: for “0”-DE particles, this is the acquisition of the function of “freedom of movement”;for “3”-DM particles (UDM), the creation of a special structure—a “double field” (“Main” and “Small”). The presence in the “double field” of specific “tools” for the creation of the worlds of the Universe—gravitational “waves” gives rise to impulses (shocks) of varying intensity and shape. A list of functions performed by “waves” in the “Main” and “Small” fields has been compiled. The specific conditions for the formation of “UDM Streams”, their transformation into a “Vortex” and, under the influence of a powerful Initial Impulse (push), sending them to the “place” of the creation of galaxies, are shown. It is suggested that there is a “Cycle of Matter in Nature” in the closed structure of our Universe due to the “work” of “waves” and the functioning of special “factories” in the form of exotic space objects—Black holes.

Mushroomβ-glucan and polyphenol formulations as natural immunity boosters and balancers:nature of the application

Mushrooms are experiencing a kind of renaissance as a part of the contemporary human diet.These valuable organisms are more than food,they fit in perfectly as a novel market group known as nutra-mycoceuticals.Immune-balancing mushroom dietary fibers and secondary metabolites such as polyphenols are the main focus of the healthcare industry.Wellness and cosmetic companies are increasingly using mushroom extracts rich in these ingredients.This review considers the basic molecular immunomodulatory mechanisms of action of the most commonly used mushroom dietary fibers,β-glucans.The literature data on their bioavailability,metabolic transformations,preclinical and human clinical research,and safety are discussed.Immunomodulatory mechanisms of polyphenol ingredients are also considered.These molecules present great potential in the design of the new immunity balancer formulations according to their widespread structural diversity.Finally,we draw attention to the perspectives of modern trends in mushroom nutraceutical and cosmeceutical formulations to strengthen and balance immunity.

Biomimetic natural biomaterials for tissue engineering and regenerative medicine:new biosynthesis methods,recent advances,and emerging applications

Biomimetic materials have emerged as attractive and competitive alternatives for tissue engineering(TE)and regenerative medicine.In contrast to conventional biomaterials or synthetic materials,biomimetic scaffolds based on natural biomaterial can offer cells a broad spectrum of biochemical and biophysical cues that mimic the in vivo extracellular matrix(ECM).Additionally,such materials have mechanical adaptability,micro-structure interconnectivity,and inherent bioactivity,making them ideal for the design of living implants for specific applications in TE and regenerative medicine.This paper provides an overview for recent progress of biomimetic natural biomaterials(BNBMs),including advances in their preparation,functionality,potential applications and future challenges.We highlight recent advances in the fabrication of BNBMs and outline general strategies for functionalizing and tailoring the BNBMs with various biological and physicochemical characteristics of native ECM.Moreover,we offer an overview of recent key advances in the functionalization and applications of versatile BNBMs for TE applications.Finally,we conclude by offering our perspective on open challenges and future developments in this rapidly-evolving field.

Facile synthesis of hierarchical NaX zeolite from natural kaolinite for efficient Knoevenagel condensation

Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficiency.Herein,we explore an economic and environmentally friendly method for synthesizing hierarchical NaX zeolite that exhibits improved catalytic performance in the Knoevenagel condensation reaction for producing the useful fine chemical 2-cyano-3-phenylacrylate.The synthesis was achieved via a low-temperature activation of kaolinite and subsequent in-situ transformation strategy without any template or seed.Systematic characterizations reveal that the synthesized NaX zeolite has both intercrystalline and intra-crystalline mesopores,smaller crystal size,and larger external specific surface area compared to commercial NaX zeolite.Detailed mechanism investigations show that the inter-crystalline mesopores are generated by stacking smaller crystals formed from in-situ crystallization of the depolymerized kaolinite,and the intra-crystalline mesopores are inherited from the pores in the depolymerized kaolinite.This synthesis strategy provides an energy-saving and effective way to construct hierarchical zeolites,which may gain wide applications in fine chemical manufacturing.

Mixing of miscible shear-thinning fluids in a lid-driven cavity

The concentration and velocity fields of two refractive index matched miscible shear-thinning fluids in a lid-driven cavity were investigated by using planar laser-induced fluorescence and particle image velocimetry,as well by computational fluid dynamics.Quantitative analyses show that the results obtained by flow simulations with the species transport model are in good agreement with the experimental results.The effects of different parameters were studied by using the intensity of segregation.For two fluids with the same rheological parameters,the relative amounts of liquids H_(1)/H and the power-law index n dominate the mixing process while the Reynolds number Re plays a marginal role.As for two fluids with density difference,buoyancy has significant influence on the mixing process.The dimensionless group Ar/Re(redefined such as to include shear thinning behavior)is proposed for assessing the effect of buoyancy and rheological properties on the mixing of miscible shear-thinning fluids.

The Man Who Organized Nature: The Life of Linnaeus by Gunnar Broberg

GunnarBroberg(1942–2022),a professor of history ideas and sciences at the Lund University in Sweden,has assembled and summarized virtually all of the contemporary documents relating to the life of Carl Linnaeus(1707–1778).This is therefore a fact-laden and definitive personal biography of the founder of our systems of plant and animal taxonomy.Linnaeus’childhood included much time in nature that forever provided him an experience background for the huge amount of plant and animal species he would encounter.In his early days,his country was in an era of poverty where“hordes of starving,homeless people drifted along the roads in the years when the harvest failed.”Linnaeus himself“...could lie awake all night as he lacked the money for evening meals when he was a student.”He inserted paper into his shoes to cover the holes on which he walked.

Genetic and epigenetic targets of natural dietary compounds as anti-Alzheimer's agents

Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults.Pathogenic factors,such as oxidative stress,an increase in acetylcholinesterase activity,mitochondrial dysfunction,genotoxicity,and neuroinflammation are present in this syndrome,which leads to neurodegeneration.Neurodegenerative pathologies such as Alzheimer’s disease are considered late-onset diseases caused by the complex combination of genetic,epigenetic,and environmental factors.There are two main types of Alzheimer’s disease,known as familial Alzheimer’s disease(onset<65 years)and late-onset or sporadic Alzheimer’s disease(onset≥65 years).Patients with familial Alzheimer’s disease inherit the disease due to rare mutations on the amyloid precursor protein(APP),presenilin 1 and 2(PSEN1 and PSEN2)genes in an autosomaldominantly fashion with closely 100%penetrance.In contrast,a different picture seems to emerge for sporadic Alzheimer’s disease,which exhibits numerous non-Mendelian anomalies suggesting an epigenetic component in its etiology.Importantly,the fundamental pathophysiological mechanisms driving Alzheimer’s disease are interfaced with epigenetic dysregulation.However,the dynamic nature of epigenetics seems to open up new avenues and hope in regenerative neurogenesis to improve brain repair in Alzheimer’s disease or following injury or stroke in humans.In recent years,there has been an increase in interest in using natural products for the treatment of neurodegenerative illnesses such as Alzheimer’s disease.Through epigenetic mechanisms,such as DNA methylation,non-coding RNAs,histone modification,and chromatin conformation regulation,natural compounds appear to exert neuroprotective effects.While we do not purport to cover every in this work,we do attempt to illustrate how various phytochemical compounds regulate the epigenetic effects of a few Alzheimer’s disease-related genes.

On Reserves of Hippophae rhamnoides L. Fruit on the Territory of the Zarafshan National Nature Park of Uzbekistan

The article is devoted to the study of stocks of Hippophae rhamnoides fruits on the territory of the Zarafshan National Park. Hippophae rhamnoides is a medicinal plant. This species is a naturally distributed plant. All parts of Hippophae rhamnoides are a source of biologically active substances, especially flavonoids, carotenoids, phytosterols and others. In the course of field studies, 10 monitoring sites were selected in the size of 10 × 10 m, and the productivity of one site in the amount of 10 × 10 averaged 51.33 ± 8.24 kg. According to the results obtained, it was revealed that the biological reserve averages 21.9 tons, respectively, the operational reserve is 13.14 tons and the volume of annual harvesting averages 1.31 tons. When the water level of the Zarafshan River rises, some plants are damaged.

The Significance of Constructing TCM Psychosomatic Medicine from the Holistic View of the Unity of Nature and Man

With the development of medical technology, the problem of fragmentation of medical research has become increasingly prominent, and a series of iatrogenic diseases, drug-induced diseases and drug toxicity and side effects have resulted in an increase in the number of diseases. In the face of these problems, the medical concept has been re-examined and re-thought. The concept of the holistic view of the unity of nature and man in traditional Chinese medicine has certain enlightenment for dealing with the problems in the current medical development. Based on the holistic view of the unity of nature and man, the overall connection between human’s heart and body and nature is explained, and the further construction of TCM psychosomatic medicine is conducive to guiding the diagnosis and treatment of clinical diseases, and providing new enlightenment for the current medical concept thinking and clinical disease research.