MILD粉体燃烧技术研究进展与关键问题分析

MILD燃烧是一种在中度或极度低氧环境下发生的温和燃烧模式,兼具高燃烧热利用率和极低NOx排放的优势,国际燃烧领域认为它是拥有巨大应用潜力的清洁燃烧技术之一。自1990年左右开展相关研究以来,对于实现气体燃料的MILD燃烧的相关技术已相对成熟,而关于煤粉和生物质等固体燃料的MILD燃烧机制和实现条件的研究仍相对缺乏。基于高动量氧化剂射流来实现内部再循环,不再需要外部高温预热来建立MILD燃烧,极大拓宽了MILD燃烧的应用范围。从颗粒弥散、受热、着火、燃烧、污染物等方面概述了MILD粉体燃料燃烧的基础特性,由于颗粒的不均匀弥散和反应,煤粉等碳基固体燃料的MILD燃烧进程较气体燃料更复杂。高速射流MILD燃烧在增加点火延迟的同时也扩展了点火区和反应区,需要对燃烧各阶段的特征和机理开展系统研究。介绍了固体燃料MILD燃烧理论设计和装备研发领域所取得的研究成果,建议通过高精度数值模拟,改进现有燃煤锅炉燃烧器、调节工艺参数以匹配MILD燃烧模式,增加焦炭颗粒的停留时间以提高燃烬率,提高燃烧稳定性并抑制包括细颗粒物在内的各类污染物排放。基于互联能源系统的整体方法,推进MILD燃烧与各类新型燃烧技术的耦合研究,尤其加强煤粉、生物质与氢、氨等可燃气体共燃特性研究,助力能源转型。探究粉体MILD燃烧中的湍流两相流特征、湍流相间传热作用以及湍流-化学耦合作用是加深对粉体MILD燃烧理解的关键,涉及多变量分析和高精度模拟,是未来研究的重点和难点。

天然气增氧MILD燃烧及NO排放特性研究

将MILD(Moderate or Intensive Low-Oxygen Dilution)燃烧和增氧燃烧相结合,以实现天然气燃烧过程中低CO_(2)和NO排放。基于0.58 MW工业炉,开展了空气预混增氧方式下天然气MILD燃烧及NO排放特性模拟研究,分析了氧气浓度(19.5%~30.0%)和氧化剂射流速度(100~300 m/s)对增氧MILD燃烧方式下炉内流场、温度和反应区分布及NO排放特性的影响。结果表明,在MILD燃烧器结构不变的条件下,当氧气浓度从19.5%增加到30.0%时,高温区更加集中,温度分布均匀性削弱,NO排放从32.4×10^(-6)增加至58.9×10^(-6),增加了82%,意味着高氧条件下MILD燃烧的低氮排放特性将会消失。然而,同氧气浓度条件下,提升氧化剂入口速度促进了烟气回流稀释,导致峰值温度下降,扩大了MILD燃烧反应区。当氧气浓度为26.5%时,将入口流速提升至150 m/s导致NO排放从49×10^(-6)降至31.2×10^(-6),可获得与空气工况下相当的NO排放水平。综上所述,空气直接预混增氧不利于MILD燃烧的形成,但通过提升氧化剂速度可实现高氧浓度条件下MILD燃烧并维持低NO排放。

Innovative pathways allow safe discharge of mild acute pancreatitis from the emergency room

Acute pancreatitis(AP)is a leading cause of gastrointestinal-related hospitalizations in the United States,resulting in 300000 admissions per year with an estimated cost of over$2.6 billion annually.The severity of AP is determined by the presence of pancreatic complications and end-organ damage.While moderate/severe pancreatitis can be associated with significant morbidity and mortality,the majority of patients have a mild presentation with an uncomplicated course and mortality rate of less than 2%.Despite favorable outcomes,the majority of mild AP patients are admitted,contributing to healthcare cost and burden.In this Editorial we review the performance of an emergency department(ED)pathway for patients with mild AP at a tertiary care center with the goal of reducing hospitalizations,resource utilization,and costs after several years of implementation of the pathway.We discuss the clinical course and outcomes of mild AP patients enrolled in the pathway who were successfully discharged from the ED compared to those who were admitted to the hospital,and identify predictors of successful ED discharge to select patients who can potentially be triaged to the pathway.We conclude that by implementing innovative clinical pathways which are established and reproducible,selected AP patients can be safely discharged from the ED,reducing hospitalizations and healthcare costs,without compromising clinical outcomes.We also identify a subset of patients most likely to succeed in this pathway.

Interfacial reaction between AZ91D magnesium alloy melt and mild steel under high temperature

The metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting process.Therefore,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is necessary.In the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild steel.Meanwhile,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and AZ91D.AlFe_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg matrix.It is found that the growth of the intermetallic layer is controlled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction process.By measuring the thickness of different layers,the growth constant was calculated.It increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the content of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe content of AZ91D than holding time.

Structural and functional connectivity of the whole brain and subnetworks in individuals with mild traumatic brain injury:predictors of patient prognosis

Patients with mild traumatic brain injury have a diverse clinical presentation,and the underlying pathophysiology remains poorly understood.Magnetic resonance imaging is a non-invasive technique that has been widely utilized to investigate neuro biological markers after mild traumatic brain injury.This approach has emerged as a promising tool for investigating the pathogenesis of mild traumatic brain injury.G raph theory is a quantitative method of analyzing complex networks that has been widely used to study changes in brain structure and function.However,most previous mild traumatic brain injury studies using graph theory have focused on specific populations,with limited exploration of simultaneous abnormalities in structural and functional connectivity.Given that mild traumatic brain injury is the most common type of traumatic brain injury encounte red in clinical practice,further investigation of the patient characteristics and evolution of structural and functional connectivity is critical.In the present study,we explored whether abnormal structural and functional connectivity in the acute phase could serve as indicators of longitudinal changes in imaging data and cognitive function in patients with mild traumatic brain injury.In this longitudinal study,we enrolled 46 patients with mild traumatic brain injury who were assessed within 2 wee ks of injury,as well as 36 healthy controls.Resting-state functional magnetic resonance imaging and diffusion-weighted imaging data were acquired for graph theoretical network analysis.In the acute phase,patients with mild traumatic brain injury demonstrated reduced structural connectivity in the dorsal attention network.More than 3 months of followup data revealed signs of recovery in structural and functional connectivity,as well as cognitive function,in 22 out of the 46 patients.Furthermore,better cognitive function was associated with more efficient networks.Finally,our data indicated that small-worldness in the acute stage could serve as a predictor of longitudinal changes in connectivity in patients with mild traumatic brain injury.These findings highlight the importance of integrating structural and functional connectivity in unde rstanding the occurrence and evolution of mild traumatic brain injury.Additionally,exploratory analysis based on subnetworks could serve a predictive function in the prognosis of patients with mild traumatic brain injury.

Exosomes derived from microglia overexpressing miR-124-3p alleviate neuronal endoplasmic reticulum stress damage after repetitive mild traumatic brain injury

We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear.In this study,we first used an HT22 scratch injury model to mimic traumatic brain injury,then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p.We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress.Furthermore,luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α,while an IRE1αfunctional salvage experiment confirmed that miR-124-3p targeted IRE1αand reduced its expression,thereby inhibiting endoplasmic reticulum stress in injured neurons.Finally,we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced.These findings suggest that,after repetitive mild traumatic brain injury,miR-124-3 can be transferred from microglia-derived exosomes to injured neurons,where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress.Therefore,microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury.

Clinical Effect of Yinhuang Qingfei Capsules in Treatment of Asymptomatic and Mild/Common Severe Acute Respiratory Syndrome Coronavirus 2 Infection:An Analysis of 242 Cases

[Objectives]To investigate the clinical effect of Yinhuang Qingfei capsules in the treatment of asymptomatic and mild/common severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection.[Methods]A total of 362 patients with SARS-CoV-2 infection were divided into the treatment group with 242 patients and control group with 120 patients according to their treatment regimen.The patients in the control group were given standard treatment regimen and those in the treatment group were given Yinhuang Qingfei capsules in addition to the treatment in the control group.The two groups were observed in terms of average length of hospital stay,mean time for nucleic acid clearance,TCM syndrome score,and progression to severe/critical illness,and clinical outcome was compared between the two groups.[Results]There was a significant difference in the overall response rate between the treatment group and the control group[97.52%(236/242)vs 95.00%(114/120),P<0.05].Compared with the control group,the treatment group had significantly shorter length of hospital stay and time for nucleic acid clearance(P<0.05).After 7 days of treatment,both groups had a significant change in TCM syndrome score,and there was a significant difference in TCM syndrome score between the two groups(P<0.05);after 15 days of treatment,both groups had a TCM syndrome score of 0.Progression to severe/critical illness was not observed in either group.[Conclusions]Compared with the standard treatment regimen alone,standard treatment regimen combined with Yinhuang Qingfei capsules can effectively shorten the length of hospital stay and time for nucleic acid clearance and improve TCM symptoms in patients with asymptomatic and mild/common SARS-CoV-2 infection.

Estimating High-Order Functional Connectivity Networks for Mild Cognitive Impairment Identification Based on Topological Structure

Functional connectivity networks (FCNs) are important in the diagnosis of neurological diseases and the understanding of brain tissue patterns. Recently, many methods, such as Pearson’s correlation (PC), Sparse representation (SR), and Sparse low-rank representation have been proposed to estimate FCNs. Despite their popularity, they only capture the low-order connections of the brain regions, failing to encode more complex relationships (i.e. , high-order relationships). Although researchers have proposed high-order methods, like PC + PC and SR + SR, aiming to build FCNs that can reflect more real state of the brain. However, such methods only consider the relationships between brain regions during the FCN construction process, neglecting the potential shared topological structure information between FCNs of different subjects. In addition, the low-order relationships are always neglected during the construction of high-order FCNs. To address these issues, in this paper we proposed a novel method, namely Ho-FCNTops, towards estimating high-order FCNs based on brain topological structure. Specifically, inspired by the Group-constrained sparse representation (GSR), we first introduced a prior assumption that all subjects share the same topological structure in the construction of the low-order FCNs. Subsequently, we employed the Correlation-reserved embedding (COPE) to eliminate noise and redundancy from the low-order FCNs. Meanwhile, we retained the original low-order relationships during the embedding process to obtain new node representations. Finally, we utilized the SR method on the obtained new node representations to construct the Ho-FCNTops required for disease identification. To validate the effectiveness of the proposed method, experiments were conducted on 137 subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database to identify Mild Cognitive Impairment (MCI) patients from the normal controls. The experimental results demonstrate superior performance compared to baseline methods.

液体燃料MILD燃烧的特性及其污染物的排放规律

为了探究液体燃料的中低氧稀释(moderate and intense low-oxygen dilution,MILD)燃烧的特性,采用数值模拟方法,分析了MILD燃烧过程中空气与燃料的入口条件对燃烧室烟气回流比、流场结构和污染物排放量的影响规律.研究结果表明:MILD燃烧室内流场结构对燃料与空气的混合起到决定作用;随着当量比的增加,燃烧室温度逐渐升高,CO的排放量逐渐增大,NO_(x)排放量也随之增大,当量比为0.9时,NO_(x)排放量达到峰值;随着空气入口速度的增加,燃烧室中心面温度分布均匀,没有明显的局部高温峰值点,NO_(x)排放量逐渐减小,CO排放量呈先减小、后增大的趋势,空气入口速度为110 m/s时的CO排放量最小;随着燃料入口速度的增大,燃烧室内峰值温度逐渐升高,NO_(x)排放量逐渐增加,CO排放量呈先减小、后增大的趋势.

高速射流煤粉MILD燃烧的研究进展

开发清洁高效的煤粉燃烧技术是应对我国乃至世界范围内日益严峻的环境污染问题的重要途径,煤粉低氧稀释(MILD)燃烧技术凭借其降低NOx排放、提高热流密度均匀性等优势而被视为颇具潜力的新型燃烧方式。同时,煤粉MILD技术结合富氧燃烧技术将是未来煤炭利用过程中减少碳排放的重要方向。综述了国内外煤粉MILD燃烧的发展历程、技术特点、研究现状等,并重点针对低温预热条件下的高速射流煤粉MILD燃烧技术探讨了研究中的关键问题和研究挑战等。煤粉MILD燃烧起源于气体燃料MILD燃烧,通过增强流场对高温烟气的卷吸并稀释反应物,使高温的火焰锋面模糊甚至消失,降低燃烧峰值温度并提升温度分布的均匀性,进而显著抑制了热力型NOx和燃料型NOx的生成。煤粉MILD燃烧可通过高温预热空气或提高射流速度实现,其中后者以其在经济性和可行性上的优势而更具发展前景,然而在速度达到100 m/s左右的高速射流的强烈剪切、湍流混合条件下的煤粉MILD燃烧机理及特性研究仍有待深入开展。在高速射流强烈剪切及卷吸作用下,煤粉弥散行为与常规射流燃烧相比有明显差异,而煤粉的弥散程度又直接关系到能否实现MILD燃烧。此外,强湍流混合会改变煤粉的升温、脱挥发分、焦炭燃烧等过程,进而影响着火延迟、火焰结构和污染物生成等煤粉燃烧过程中的关键问题。基于对上述关键问题的深入了解并结合气体燃料MILD燃烧的相关研究基础,可进一步发展针对煤粉MILD燃烧的系统、准确的定义,以更好地指导煤粉MILD燃烧技术的研究与应用。

煤粉MILD燃烧NO_(x)生成和还原机理的数值分析

采用计算流体动力学(CFD)软件分析了国际火焰研究基金会(IFRF)试验系统上煤粉低氧稀释(MILD)燃烧特性和NO_(x)排放特性。比较了不同的湍流与化学反应相互作用模型、挥发分气相反应机理和焦炭燃烧模型对煤粉MILD燃烧特性预测的影响,通过对比烟气速度场、温度场、组分浓度场的模型预报结果与试验结果,得到了能够准确预测煤粉MILD燃烧特性的模型组合,即EDC-WD-MSR模型。采用此模型对煤粉MILD燃烧NO_(x)生成和还原路径进行分析,结果表明:煤粉MILD燃烧中燃料型NO占主导地位,热力型NO、N_(2)O中间体路径和快速型NO之和对NO总排放的贡献小于10%。煤粉MILD燃烧存在强烈的NO均相和异相还原反应,其中NO异相还原反应使燃料型NO的排放量占单独计算的焦炭NO和挥发分NO排放量之和的71.1%。

Proteomics of serum exosomes identified fibulin-1 as a novel biomarker for mild cognitive impairment

Mild cognitive impairment(MCI)is a prodrome of Alzheimer’s disease pathology.Cognitive impairment patients often have a delayed diagnosis because there are no early symptoms or conventional diagnostic methods.Exosomes play a vital role in cell-to-cell communications and can act as promising biomarkers in diagnosing diseases.This study was designed to identify serum exosomal candidate proteins that may play roles in diagnosing MCI.Mass spectrometry coupled with tandem mass tag approach-based non-targeted proteomics was used to show the differentially expressed proteins in exosomes between MCI patients and healthy controls,and these differential proteins were validated using immunoblot and enzyme-linked immunosorbent assays.Correlation of cognitive performance with the serum exosomal protein level was determined.Nanoparticle tracking analysis suggested that there was a higher serum exosome concentration and smaller exosome diameter in individuals with MCI compared with healthy controls.We identified 69 exosomal proteins that were differentially expressed between MCI patients and healthy controls using mass spectrometry analysis.Thirty-nine exosomal proteins were upregulated in MCI patients compared with those in control patients.Exosomal fibulin-1,with an area under the curve value of 0.81,may be a biomarker for an MCI diagnosis.The exosomal protein signature from MCI patients reflected the cell adhesion molecule category.In particular,higher exosomal fibulin-1 levels correlated with lower cognitive performance.Thus,this study revealed that exosomal fibulin-1 is a promising biomarker for diagnosing MCI.

MILD燃烧方式下燃料NO_(x)生成特性数值模拟

针对MILD燃烧新模式下燃料NO_(x)生成特性暂不清楚的问题,开展了甲烷MILD燃烧的CFD数值模拟.通过向燃料中添加不同比例的NH_(3),考察了NH_(3)添加对MILD燃烧方式下燃料NO_(x)生成特性的影响,对于明确MILD燃烧降低燃料NO_(x)排放的可行性具有重要意义.在分析现有CH_(4)/NH_(3)反应机理可靠性的基础上提出了改进模型,并进行了甲烷MILD燃烧火焰结构和NO排放的实验验证.研究结果表明:随着燃料中NH_(3)含量的增加,无论是常规燃烧还是MILD燃烧下NO排放都相应提高;同时,MILD燃烧下特殊的燃料氧化过程导致NO的还原作用弱于常规燃烧,因此当燃料中初始NH_(3)体积分数超过1.3%后NO排放值反而高于常规燃烧.

Quantitative proteomic and phosphoproteomic analyses of the hippocampus reveal the involvement of NMDAR1 signaling in repetitive mild traumatic brain injury

The cumulative damage caused by repetitive mild traumatic brain injury can cause long-term neurodegeneration leading to cognitive impairment.This cognitive impairment is thought to result specifically from damage to the hippocampus.In this study,we detected cognitive impairment in mice 6 weeks after repetitive mild traumatic brain injury using the novel object recognition test and the Morris water maze test.Immunofluorescence staining showed that p-tau expression was increased in the hippocampus after repetitive mild traumatic brain injury.Golgi staining showed a significant decrease in the total density of neuronal dendritic spines in the hippocampus,as well as in the density of mature dendritic spines.To investigate the specific molecular mechanisms underlying cognitive impairment due to hippocampal damage,we performed proteomic and phosphoproteomic analyses of the hippocampus with and without repetitive mild traumatic brain injury.The differentially expressed proteins were mainly enriched in inflammation,immunity,and coagulation,suggesting that non-neuronal cells are involved in the pathological changes that occur in the hippocampus in the chronic stage after repetitive mild traumatic brain injury.In contrast,differentially expressed phosphorylated proteins were mainly enriched in pathways related to neuronal function and structure,which is more consistent with neurodegeneration.We identified N-methyl-D-aspartate receptor 1 as a hub molecule involved in the response to repetitive mild traumatic brain injury,and western blotting showed that,while N-methyl-D-aspartate receptor 1 expression was not altered in the hippocampus after repetitive mild traumatic brain injury,its phosphorylation level was significantly increased,which is consistent with the omics results.Administration of GRP78608,an N-methyl-D-aspartate receptor 1 antagonist,to the hippocampus markedly improved repetitive mild traumatic brain injury-induced cognitive impairment.In conclusion,our findings suggest that N-methyl-D-aspartate receptor 1 signaling in the hippocampus is involved in cognitive impairment in the chronic stage after repetitive mild traumatic brain injury and may be a potential target for intervention and treatment.

基于主成分分析、聚类和BP神经网络的湍流MILD燃烧初始着火过程的分析

在MILD燃烧中,湍流和燃烧的相互作用十分强烈,尤其是在初始着火过程,识别该过程的火焰推进对于理解燃烧形成过程、稳定燃烧条件有很大帮助.采用MILD燃烧HM1工况的大涡模拟数据,探索了一种基于主成分分析(PCA)、聚类和反向传播神经网络(BPNN)的动态燃烧场识别方法,对稳态燃烧场进行PCA和聚类后,基于BPNN对初始着火过程进行动态识别和分析.结果表明,该方法用于着火过程动态燃烧场识别是可行的,与传统方法相比具有客观、高效的特点,是一种实用的工业火焰测量方法.

步进式板坯加热炉应用MILD富氧燃烧的数值模拟

针对某钢厂步进式板坯加热炉,建立了炉内燃烧、流动及传热的全耦合三维模型,并使用滑移网格模拟钢坯运动.为了实现MILD富氧燃烧,采用在加热炉侧烧嘴旁通入高速氧气射流的方式卷吸烟气及燃料,重点分析了该工况下加热炉内流场、温度场、钢坯温度、加热炉产量及NO_(x)排放的变化情况.结果表明:经MILD富氧燃烧改进后,加热炉侧烧嘴的加热能力得到提高,钢坯在炉宽方向上的受热均匀性也得到保证;将钢坯加热至符合出炉温度需要114 min,使用的燃料量为96 307.7 m^(3),加热炉产量提高了6.35%,烟气出口的NOx浓度为58.35 mg/m^(3),NO_(x)排放量减少了46.5%.

Mesoporous titanium-aluminosilicate as an efficient catalyst for selective oxidation of cyclohexene at mild reaction conditions

Mesoporous titanium containing alumino-silicate materials with various titanium/silicon(Ti/Si) ratio(AlSi-Ti(n);n = Ti/Si mole ratio) have been successfully synthesized by a novel single-step sodium(Na)-free method, for the first time. The obtained characterization results of the prepared materials reveal that in-situ addition of Ti into AlSi shows ordered mesoporous structure along with uniformly dispersed Ti species in +4 and +3 oxidation states suitable for selective oxidation of allylic C—H bond. The prepared mesoporouse Ti-AlSi(n) samples exhibited excellent activity in the oxidation of cyclohexene with 100%conversion and 100% selectivity to ketone-alcohol(KA) oil(cyclohex-2-en-1-ol and 2-cyclohexen-1-one) at low temperature and reaction time(35℃ and 30 min reaction time). This study suggests that AlSi-Ti(0.05) material can be a promising catalyst for the selective oxidation of cyclohexene under mild reaction conditions.

Enhanced adsorption of target branched compounds including antibiotic norfloxacin frameworks on mild steel surface for efficient protection: An experimental and molecular modelling study

In this study, an approach was proposed to employ new target branched compounds(TBCs) including multiple antibiotic norfloxacin frameworks for intensified adsorption films to achieve super protection of mild steel in HCl medium. Thus, the TBCs containing bis/tri norfloxacin skeletons were synthesized by multi-step preparation route. In addition, the reference linear compound(RLC) including a single norfloxacin part was also synthesized. The chemical structures of these compounds were confirmed by various means. It was demonstrated that the TBCs could form the tough adsorption films on the surface of mild steel, which could be processed mainly through chemisorption effect. The electrochemical analysis suggested that the TBCs displayed superior corrosion inhibition performance for low carbon steel in1.0 mol·L^(-1) HCl solution over the RLC(RLC, 87.80%;TBC1, 97.63%;TBC2, 98.35%), which was further understood by the molecular modelling. The isotherm adsorption plots were employed to analyze the spontaneous adsorption process of the TBCs on low carbon steel surface, and a prominent chemisorption could be inferred by the standard Gibbs free energy changes of the adsorption.

Receded near point of convergence as a predictor of mild cognitive impairment in the general geriatric population:results from a population-based study

AIM:To investigate the relationship between near point of convergence(NPC)and mild cognitive impairment(MCI)in the general elderly population.METHODS:The present report is a part of the Tehran Geriatric Eye Study(TGES):a population-based crosssectional study conducted on individuals 60 years of age and above living in Tehran,Iran using the multi-stage stratified random cluster sampling method.Cognitive status was assessed using the Persian version of the Mini-Mental State Examination(MMSE).All study participants underwent complete ocular examination including measurement of uncorrected and best-corrected visual acuity,objective and subjective refraction,cover testing,NPC measurement,and slit-lamp biomicroscopy.RESULTS:The data of 1190 individuals were analyzed for this report.The mean age of the participants analyzed was 66.82±5.42(60-92y)and 728(61.2%)of them were female.Patients with MCI had a significantly more receded NPC compared to subjects with normal cognitive status(10.89±3.58 vs 7.76±2.71 cm,P<0.001).In the multivariable logistic regression model and in the presence of confounding variables,a receded NPC was statistically significantly associated with an increased risk of MCI(odds ratio:1.334,95%confidence interval:1.263 to 1.410,P<0.001).According to receiver operating characteristic(ROC)analysis,a cut point NPC>8.5 cm(area under the curve:0.764,P<0.001)could predict the presence of MCI with a sensitivity and specificity of 70.9%and 69.5%,respectively.CONCLUSION:A receded NPC can be clinically proposed as a predictor of MCI in older adults.It is recommended that elderly with a receded NPC>8.50 cm undergo detailed cognitive screening for a definite diagnosis of MCI.In this case,the necessary interventions can be carried out to slow down MCI progression to dementia.

Degradation of Alkaline Lignin in the Lactic Acid-Choline Chloride System under Mild Conditions

Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be used as an excellent green degradation method.This paper introduces the degradation mechanism and effect of the lactic acid-choline chloride DES system in dissolving and degrading alkaline lignin,and the final solvent recovery.It can also be found from the scanning electron microscope(SEM)images that the surface of the degraded solid product is transformed from smooth to disordered.Fourier transform infrared(FTIR)spectroscopy and 1H-NMR spectroscopy were used to characterize the changes in lignin functional groups during DES treatment.The results showed that the content of phenolic hydroxyl groups increased after degradation,indicating that theβ-O-4 ether bond was broken.The molecular weight of the degraded lignin was observed by gel permeation chromatography(GPC),and the lignin residue with low molecular weight and narrow polydispersity index was obtained.The lowest average molecular weight(Mw)reached 2512 g/mol.The ratio of oxygen to carbon atoms in lignin increased substantially during degradation as measured by X-ray photoelectron spectroscopy(XPS),probably because DES treatment was accompanied by many oxidation reactions,which led to significant structural changes in lignin and a large number of ether bond breakage reactions during the reaction.The main final degradation products are aromatic monomers,vanillin,butyrovanillone,etc.