Major challenges and recent advances in characterizing biomass thermochemical reactions

Thermochemical conversions are pathways for biomass utilization to produce various value-added energy and chemical products. For the development of novel thermochemical conversion technologies, an accurate understanding of the reaction performance and kinetics is essential. Given the diversity of the thermal analysis techniques, it is necessary to understand the features and limitations of the reactors, ensuring that the selected thermal analysis reactor meets the specific need for reaction characterization. This paper provides a critical overview of the thermal analysis reactors based on the following perspectives: 1) gas flow conditions in the reactor, 2) particle’s external and internal heat and mass transfer limitations, 3) heating rate, 4) temperature distribution, 5) nascent char production and reaction, 6) liquid feeding and atomization, 7) simultaneous sampling and analyzing of bed materials, and 8) reacting atmosphere change. Finally, prospects and future research directions in the development of analysis techniques are proposed.

二烯丙基二硫在RORα抑制人胃癌细胞上皮间质转化中的作用

目的探讨二烯丙基二硫(DADS)是否上调维甲酸相关孤核受体α(RORα)抑制人胃癌细胞株MGC803细胞上皮-间质转化(EMT)。方法相差显微镜观察MGC803细胞形态的改变。逆转录PCR(RTPCR)、蛋白免疫印迹法(Western blot)、免疫荧光与免疫组织化学检测EMT的相关分子表达。裸鼠实验检测DADS与沉默RORα对移植瘤生长的影响。结果相差显微镜显示,沉默RORα细胞较MGC803细胞大小与形状差异更明显。DADS作用后,细胞大小较一致,呈圆形或椭圆形,梭形细胞减少,异型性下降。RT-PCR与Western blot显示,DADS处理后较处理前各组RORαm RNA与蛋白表达上调(P<0.05)。DADS作用对照组与空载体组较沉默组效果更为明显(P<0.05)。RORα沉默较对照组和空载体组细胞锌指转录因子(Snail)和波形蛋白(Vimentin)m RNA与蛋白表达上调,而E-钙黏蛋白(E-cadherin)m RNA与蛋白下调(P<0.05)。DADS处理后,各组Snail蛋白下调、Vimentin m RNA与蛋白下调和E-cadherin m RNA与蛋白上调(P<0.05)。免疫荧光显示,沉默组细胞Snail与Vimentin阳性表达较对照组增强,而E-cadherin阳性表达减弱。DADS作用后,结果相反。裸鼠移植瘤实验显示,RORα沉默组移植瘤较对照组生长加快和体重增加(P<0.05),增殖细胞核抗原(Ki-67)、Snail、CD34及Vimentin阳性表达较对照组增加,而E-cadherin阳性降低。DADS处理各组移植瘤生长与体积减慢与减小,Ki-67、Snail、CD34与Vimentin阳性表达较对照组减弱,而E-cadherin阳性表达增强。结论 DADS通过上调RORα可体内外抑制人胃癌MGC803细胞EMT。

Recent advances in slippery liquid-infused surfaces with unique properties inspired by nature

The slippery liquid-infused porous surface(s)(SLIPS)that imitates the Nepenthes pitcher plant has proven to be highly versatile and can be combined with various surface characteristics such as dynamic response,antifouling,selective adhesion,and optical/mechanical tunability.In addition,the introduction of a lubricating fluid layer also gives it extremely low contact angle hysteresis and self-repairing properties,which further expands its application range.Currently,SLIPS has been proven to be suitable for many frontier fields such as aerospace,communications,biomedicine,and microfluidic manipulation.In this review,we explain the theoretical background of SLIPS and the preparation methods currently available,including the choice of substrate materials and lubricants,and we discuss the design parameters of the liquid injection surface and how to deal with the consumption of lubricants in practical applications.In addition,the paper focuses on current and potential applications,such as preventing pathogen contamination of and blood adhesion of medical equipment,manipulation of tiny droplets,and directional transportation of liquids.Finally,some weaknesses that appear when SLIPS is used in these applications are pointed out,which provides a new perspective for the development of SLIPS in the future.

Suppressing secondary reactions of coal pyrolysis by reducing pressure and mounting internals in fixed-bed reactor

Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting internals particularly designed greatly improved the heat transfer inside coal bed and raised the yield of tar production.Reducing pressure further facilitated the production of tar through its suppression of secondary reactions occurring in the reactor. The absolute increase in tar yield reached 3.33 wt% in comparison with the pyrolysis in the reactor without internals under atmospheric pressure. The obtained tar yield in the reactor with internals under reduced pressure was even higher than the yield of Gray–King assay. Through experiments in a laboratory fixed bed reactor, it was also clarified that the effect of reducing pressure is related to volatile release rate in pyrolysis. It did not obviously vary tar yield at pyrolysis temperatures below 600 ℃, while the effect was evident at 650 and 700 ℃ but became limited again above 800 ℃. Under reduced pressure the produced tar contained more aliphatics and phenols but less aromatics.

Synergetic NO reduction by biomass pyrolysis products simulating their reburning in circulating fluidized bed decoupling combustion

The present work investigated the synergetic effect of pyrolysis-derived char,tar and gas(py-gas)on NO reduction,which may occur in circulating fluidized-bed decoupling combustion(CFBDC)system treating N-rich fuel.Experiments were carried out in a lab-scale drop-tube reactor for NO reduction by some binary mixtures of reagents including char/py-gas,tar/py-gas and tar/char.At a specified total mass rate of0.15 g·min^-1 for NO-reduction reagent,the char/py-gas(binary reagent)enabled the best synergetic NO reduction in comparison with the others.There existed effective interactions between char and some species in py-gas(i.e.,H2,CxHy)during NO reduction by pyrolysis products,meanwhile the tar/py-gas or tar/char mixture only caused a positive effect when tar proportion was necessarily lowered to about 26%.On the other hand,the synergetic effects were not improved for all tested binary reagents by increasing the reaction temperature and residence time.

Synaptosomal-associated protein 25 may be an intervention target for improving sensory and locomotor functions after spinal cord contusion

Synaptosomal-associated protein 25 k Da（SNAP-25） is localized on the synapse and participates in exocytosis and neurotransmitter release. Decreased expression of SNAP-25 is associated with Alzheimer＇s disease and attention deficit/hyperactivity disorder. However, the expression of SNAP-25 in spinal cord contusion injury is still unclear. We hypothesized that SNAP-25 is associated with sensory and locomotor functions after spinal cord injury. We established rat models of spinal cord contusion injury to detect gene changes with a gene array. A decreased level of SNAP-25 was detected by quantitative real time-polymerase chain reaction and western blot assay at 1, 3, 7, 14 and 28 days post injury. SNAP-25 was localized in the cytoplasm of neurons of the anterior and posterior horns, which are involved in locomotor and sensory functions. Our data suggest that reduced levels of SNAP-25 are associated with sensory and locomotor functions in rats with spinal cord contusion injury.

Tendencies of research and development in resources chemicals and materials -Summarization of a Youth’s topic forum

The 2022′s Youth Forum on Resources Chemicals and Materials was held on November 12-13,2022,in Shenyang,Liaoning Province.Panel discussions focus on the cutting-edge researches on“Fine chemicals and advanced alloy materials”and“Utilization of fossil and renewable carbon resources”.This perspective summarizes the major di-rections of scientific research and technical developments aligned in the discussions.Fine chemical industry tends to pursue green and low-carbon products,intelligent product design,and start manufacturing.In recent years,great efforts have been made for transformation of cellulose into advanced electronic as well as life-service bio-materials and to the high-selectivity extraction of bio-base aromatic chemicals from lignin.Concerning high-end alloy materials,regulating deformation mechanism of crystal to construct bimodal microstructure seems highly prospective in harmonizing precipitate hardening effect and plastic deformation capacity.As we know,utiliza-tion of fossil carbon resources constitutes the major anthropogenic carbon emissions,and the related innovations thus should be,for possibly a long period,on increasing energy production efficiency and low-carbon cascaded conversion of fossil fuels,especially of coal.

Micro reactors for measurement and analysis of thermochemical gas-solid reactions

Micro reactors are the essential part of thermal analysis techniques for characterizing gas-solid thermochemical reactions. The dynamic and diversified needs for investigating various complex materials and gas-solid reactions have led to the development of a variety of different microreactors over the years. Solid particles in microreactors are normally heated by furnaces from outside, resistive elements from inside, direct contact with bed particles, or other non-resistively methods. Solid particles can be fixed or fluidized in reactors where gas-solid contacts vary from diffusion-dominated to nearly diffusion-free conditions. Based on these characteristics, in this article we presented a broad classification for microreactors used for thermal analysis of gas-solid reactions. For each of the most popularly used microreactors, their features and limitations are briefly reviewed. By addressing the diversity of the microreactors used in the field of thermal analysis, the review aims at providing general guidance for the selection and operation of the microreactor to satisfy one's practical specific needs.

Lead-free hybrid two-dimensional double perovskite with switchable dielectric phase transition

Molecular dielectric switches constitute a type of intelligent materials that are highly coveted for their distinctive advantages of switchable dielectric responses,lightweight,and mechanical flexibility.Twodimensional(2D)hybrid perovskites have demonstrated excellent promise for assembling dielectric switches,in which the dynamic motions of organic moieties afford driving force to trigger switchable dielectric phase transition.Here,we successfully assembled a new lead-free hybrid double perovskite,(CHA)4Cu Bi Br8(1,CHA=cyclohexylammonium),adopting a typical 2D structural motif,which shows dielectric anisotropy and bistable behaviors during the reversible phase transition near T_(c)=378 K(the Curie temperature).That is,its dielectric constants could be switched and tuned between high-dielectric and low-dielectric states.Structure analyses reveal that the ordered-disordered transformation of the organic CHA+moiety and distortion of inorganic framework account for its phase transition.This result will stimulate further exploration of molecular dielectric switches in this 2D environmentally friendly family.

DMF-scMT-seq linking methylome and transcriptome within single cells with digital microfluidics

Single-cell joint analysis of methylome and transcriptome reveals how the methylation regulates the transcriptional activity.However,traditional bench-top protocols for single-cell DNA methylation and RNA transcription co-detection are laborintensive,cost-ineffective and contaminant-prone.Herein,we establish the DMF-sc MT-seq,a highly-efficient and cost-effective method to simultaneously analyze single-cell DNA methylation and transcriptional activity based on digital microfluidics.DMFsc MT-seq automates the workflow of single-cell isolation,cellular hypotonic lysis,nucleic acid separation and methylome/transcriptome library construction in a contactless and addressable way.The system ensures high accuracy(R>0.85),high gene detection ability(14,697 genes per cell at 4 million sequencing depth),and high CpG coverage(677,198 CpG sites per cell at 1million sequencing depth).By using DMF-sc MT-seq,the relationship of DNA methylation and RNA transcription under different genomic contexts is resolved.We further apply DMF-sc MT-seq to study the dynamics of transcription regulation with methylation-inhibiting anti-tumor Decitabine,and identify the methylated promoter/gene body driven genes in response to Decitabine treatment.DMF-sc MT-seq facilitates the construction of the correlation of DNA methylation and transcriptional activity at the single-cell level in a flexible,sensitive and accurate way,which is anticipated to be a powerful tool in studying single-cell biological systems.

Controlled fabrication of Fe_(3)N@NG composites as superior oxygen evolution reaction electrocatalysts

We report the controlled fabrication of nitrogen doped graphene(NG)nanoplates,which are uniformly decorated with iron nitride(Fe_(3)N)nanoparticles,via ball milling of mixtures of graphite and iron nitrates and the following ammonia annealing.The obtained Fe_(3)N@NG composites demonstrate excellent electrocatalytic activity and durability for oxygen evolution reaction,both of which outperform those of the state-of-the-art iridium oxide catalysts.This may be attributed to nitrogen doping as well as the synergistic effect between Fe3N and graphene nanoplates.

Role of gut microbiota in ischemic stroke:A narrative review of human and animal studies

The high incidence,mortality,and disability associated with ischemic stroke pose a significant threat to human health.The intestinal microbiota significantly influences the onset,progression,and prognosis of ischemic stroke.Gut flora plays a pivotal role in brain-gut interactions.The reflection of changes in the gut and brain caused by gut microbes faciltates the investigation of early warning biomarkers and potential therapeutic targets for ischemic stroke.In this narrative review of the relationship between gut microbiota and ischemic stroke,we primarily discuss three topics,grounded in real-world human and animal studies.First,we examined the relationship between ischemic stroke and intestinal microbiota and its metabolites,delineate the overall characteristics of intestinal microbiota dysregulation in ischemic stroke,and assess the potential clinical value,prevailing research controversies,and unique phenomena of intestinal microbiota metabolites such as trimethylamine N-oxide and short-chain fatty acids in ischemic stroke.Second,we explored the potential communication pathways between intestinal flora and ischemic stroke based on the brain-gut axis,encompassing metabolic pathways,immune pathways,and neural pathways.Finally,we encapsulated the factors influencing the severity of ischemic stroke via intestinal flora,the pharmacological and nonpharmacological interventions that modulate intestinal flora in treating ischemic stroke,and the current research landscape of intestinal flora in the context of ischemic stroke sequelae.

金属氧化物对生物质半焦气化特性和反应动力学影响

为测试生物质半焦中金属氧化物的催化作用,本研究利用热重分析仪比较脱灰半焦(ALC)及负载金属氧化物半焦(ALC-K_(2)O,ALC-Na_(2)O,ALC-CaO,ALC-Fe_(2)O_(3),ALC-MgO)的气化特性,并进行动力学计算。为提高结果准确性,采用等温和非等温实验方法,并利用分布活化能模型(DAEM)和Flynn-Wall-Ozawa(FWO)等转化率法求算动力学。结果表明,金属氧化物对半焦催化效果有明显差异。等温条件下,其气化活性依次为ALC-K_(2)O>ALC-Na_(2)O>ALC-CaO>ALC-Fe_(2)O_(3)>ALC-MgO>ALC。非等温条件下,相同升温速率下,各半焦的特征汽化温度(初始温度、最大速率下温度、结束温度)由小到大依次为ALC-K_(2)O,ALC-Na_(2)O,ALC-CaO,ALC-Fe_(2)O_(3),ALC-MgO,ALC,低特征反应温度表明其高反应活性。动力学分析发现,无论是等温还是非等温气化,活化能数据依次为ALC-K_(2)O<ALC-Na_(2)O<ALC-CaO<ALC-Fe_(2)O_(3)<ALC-MgO<ALC,这与气化活性趋势相吻合。对比等温气化,非等温气化的活化能偏大,但随转化率增加变化平稳。

Circular RNA circCCNB1 inhibits the migration and invasion of nasopharyngeal carcinoma through binding and stabilizing TJP1 mRNA

Nasopharyngeal carcinoma(NPC)is a malignant tumor that usually occurs in people from Southeast Asia and Southern China.NPC is prone to migration and invasion,leading to poor prognosis.A large number of circular RNAs(circ RNAs)exacerbate the process of metastasis in NPC;however,their underlying mechanisms remain unclear.We found that the circular RNA circ CCNB1,encoded by the oncogene CCNB1,was downregulated in NPC biopsies and cell lines.In vitro assays show that circ CCNB1 inhibits NPC cell migration and invasion.Moreover,circ CCNB1 induces a protein,nuclear factor 90(NF90),to bind and prolong the half-life of tight junction protein 1(TJP1)m RNA.Upregulation of TJP1 enhances tight junctions between cancer cells and inhibits NPC cell migration and invasion.This study reveals a novel biological function of circ CCNB1 in the migration and invasion of NPC by enhancing the tight junctions of cancer cells by binding to NF90 proteins and TJP1 m RNA,and may provide a potential therapeutic target for NPC.

Synthesis and characterization of a sensitive and selective Fe^(3+) fluorescent sensor based on novel sulfonated calix[4]arene-based host-guest complex

A novel fluorescent sensor was prepared from sulfonated calix[4]arene(SC4A)by the host-guest com-plexation method using the fluorescent dye rhodamine B(RB)as a structure-directing agent.The crystal structure of the host-guest complex(RB@(SC4A)_(3))was confirmed by X-ray diffraction studies while its performance and sensing mechanism for metal ion pollutants were characterized using fluorescence and nuclear magnetic resonance spectroscopies.The results showed that RB@(SC4A)_(3) had a triangular branch structure resulting from host-guest mediation of the interactions between the three SC4A host molecules and the three terminal groups of the guest molecule RB.The host-guest complex exhibited sensitive and selective sensing towards Fe^(3+)ions via a fluorescence quenching mechanism.The results indicated that RB@(SC4A)_(3) could be a promising sensitive and selective fluorescent sensor for metal ion pollutants mon-itoring.It also provided new insights into the synthesis of calixarene-based host-guest complex.

Reaction decoupling in thermochemical fuel conversion and technical progress based on decoupling using fluidized bed

Thermochemical conversion of fuels via pyrolysis/carbonization,cracking,gasification and combustion has to involve a number of individual reactions called attribution reactions to form an intercorrelated reaction network for any conversion process.By separating one or some attribution reactions from the others to decouple their interactions existing in the reaction network,the so-called reaction decoupling enables a better understanding of the complex thermal conversion process and further the optimization of the conditions for attribution reactions as well as the entire conversion process to realize advanced performances.The dual bed conversion and two-stage conversion are the two representative types of fuel conversion technologies developed in recent years based on reaction decoupling.Many technical advantages have been proven for such decoupling fuel conversion technologies,such as poly-generation of products,low-cost production of high-grade products,elimination of undesirable products or pollutants,easy operation and control,and so on.The treated fuels with decoupling conversion technologies mainly include solid biomass and coal,as well as liquid petroleum oil.This paper is devoted to reiteration of the reaction decoupling concept and further to reviewing the research,developments and successful applications of several decoupling fuel conversion technologies of two such types by using fluidized bed as their major reactors.

Characterization and pilot scale test of a fluidized bed two-stage gasification process for the production of clean industrial fuel gas from low-rank coal

To utilize low rank coal efficiently,a fluidized bed two-stage(FBTS)gasification process,mainly consisting of a FB pyrolyzer and a transport FB(TFB)gasifier,has been proposed for the production of clean fuel gas.To verify the feasibility and technical features of this novel gasification technology,a pilot autothermal platform,with a treating capacity of 100 kg/h for coal,was designed and built up.By adopting a kind of lignite from Inner Mongolia,the running state and fuel gas quality were compared systematically under typical operational conditions.The results show that by keeping the reaction temperatures of pyrolyzer and gasifier at around 840
C and 1000
C,respectively,the corresponding tar content in fuel gas at the outlets of pyrolyzer and gasifier were 1127 mg/Nm3 and 365 mg/Nm3,reaching a high tar removal efficiency.Under the stable operation state,the volume fractions of CO,H2,CH4 and CO2 in fuel gas were 14.4%,8.3%,3.4%and 11.3%,respectively,and the corresponding higher heating value of fuel gas was about 1100 kcal/Nm3.Compared with the tar from pyrolyzer,the heavy oil fraction in tar from gasifier reduced significantly,while the light oil components increased sharply simultaneously,showing significant effect of catalytic reforming by hot char bed on tar removal.

Recent progress in tar removal by char and the applications:A comprehensive analysis

Tar catalytic removal by char is a promising technology for gasification process because of its porous structure,good catalytic activity,low cost,and easy to treatment after deactivation.To provide comprehensive information on the tar catalytic removal by char,this study focuses on the ongoing efforts and advances from fundamental researches to the industrial applications.The tar removal efficiency by char much depends on reaction conditions and char property,such as char origin,porous structure,the functional group on char surface,carbon structure,and AAEM components.The typical reaction kinetics,reaction mechanism,and the deactivation,will be introduced.Then,for the different gasification processes,the potential or typical applications of tar removal by char are discussed and compared.Finally,a comprehensive analysis and improvement in scaling up,commercializing tar removal technologies and integrating the gasification process,are also evaluated and analyzed in this review.

Pyrolysis characteristics of waste tire particles in fixed-bed reactor with internals

This study investigated the characteristics of pyrolysis for waste tire particles in the newly developed fixed-bed reactor with internals that are a central gas collection channel mounted inside reactor.And a few metallic plates vertically welded on the internal wall of the reactors and extending to the region closing their central gas collection pipe walls.Experiments were conducted in two laboratory fixed bed reactors with or without the internals.The results shown that employing internals produced more light oil at externally heating temperatures above 700℃due to the inhibited secondary reactions in the reactor.The oil from the reactor with internals contained more aliphatic hydrocarbons and fewer aromatic hydrocarbons,leading to its higher H/C atomic ratios as for crude petroleum oil.The char yield was relatively stable for two beds and showed the higher heating values(HHVs)of about 23 MJ/kg.The gaseous product of pyrolysis mainly consisted of H2 and CH4,but the use of internals led to less pyrolysis gas through its promotion of oil production.

Characteristics of gas-solid micro fluidized beds for thermochemical reaction analysis

Fuel conversion and clean energy reaction systems involve a variety of catalytic and non-catalytic gas-solid thermochemical reactions.A good understanding of the correct reaction mechanism and kinetics,as well as the profiles of reaction products,is of great significance to the development,design,and operation of such reaction systems.The micro fluidized bed reaction analysis provides an efficient and reliable method to acquire this essential information with low capital and operating costs,low energy consumption and enhanced safety.This paper provides an overview of the system and its characteristics for the micro fluidized bed reaction analyzer that has been well proven to be a reliable new approach as well as an instrument for characterizing various gas-solid thermochemical reactions.