Current status of emergency treatment of chemical eye burns in workplaces

Chemical eye burns present an avoidable,but frequent,occupational injury with potentially detrimental consequences for the quality of life and occupational rehabilitation of the injured.A periodical review of guidelines is required to assure the optimal emergency management.We reviewed the literature with emphasis on current German guidelines,primarily MEDLINE.If the crucial first-line measure,the injury prevention has failed and an eye burn has been sustained,the immediate and copious rinsing of the eye is the pivotal emergency treatment modality.Whereas the immediacy and sufficiency of the emergency rinsing are largely unanimous,there is an ongoing debate about the benefits and risks of specific rinsing solutions,and regular updates on guidelines and recommendations for the emergency treatment are warranted.The easiest and readily available rinsing solution is tap water,which fulfils the crucial criteria conveniently in most industrialized countries:purity,sterility,and neutral p H.Other rinsing solutions are proposing higher osmolality to stabilize the physiological p H,because of their superior buffering capacity.However,there is no compelling evidence for a substantial benefit,and some reports suggest that there could be unwanted side effects.In combination with the substantially increased expenditure and a more complex handling procedure,currently a general recommendation of any other solution than tap water is not warranted.

Analysis of the Cicatricial Acceleration Method (MAC®) in Skin Repair in Wistar Rattus norvegicus with Induced Chemical Burns

Introduction: The cicatricial acceleration method (MAC®) promotes photobiological effects of an anti-inflammatory and healing nature. Its therapeutic radiation is emitted, producing photobiostimulant effects that result in rapid tissue repair and better tissue quality. The treatment of burns has always been a challenge, which involves both performing surgery and controlling and guiding scar regeneration, avoiding possible morbidities. Objective: To evaluate the effects of applying the MAC methodology with an AlGa (aluminum, gallium arsenide) laser on the time and quality of tissue repair in the skin of rats after induced chemical burns. Method: 22 adult male rats were subjected to a second-degree chemical burn on the back using 50% trichloroacetic acid. After the burns, the animals were randomly separated into 2 groups: control and experimental. The control group (G1) received placebo laser therapy and the laser group (G2) underwent laser irradiation with an energy density of 100 J/cm2. Histological analysis and macroscopic evaluation were carried out by means of the paper template method. Results: Group G1 showed (53%) of the necrosis area and group G2 showed (11%) necrosis area. Conclusion: The cicatricial acceleration method (MAC®) favored the repair of wounds caused by a 2nd-degree chemical burn, optimizing time and improving quality.

Common eye drops and their implications for p H measurements in the management of chemical eye injuries

Dear Sir,Eye drops(single use)commonly used in clinics do have varying pH values.The use of such drops in the initial management of chemical eye injury may influence the accuracy of pH measurement of the eye,and subsequently influence its management.Chemical eye injury is an ophthalmic emergency,which may be caused by exposure to an acidic(pH【4)or an alkali(pH】10)solution to the eye.Rinsing the eye decreases the concentration of these solutions on ocular surface.The initial management would be copious irrigation with clean or sterile water or Ringer’s solution(pH 7.3-7.4)or its equivalent,of a

A Rational Design of Metal–Organic Framework Nanozyme with High‑Performance Copper Active Centers for Alleviating Chemical Corneal Burns

Metal–organic frameworks(MOFs)have attracted significant research interest in biomimetic catalysis.However,the modulation of the activity of MOFs by precisely tuning the coordination of metal nodes is still a significant challenge.Inspired by metalloenzymes with well-defined coordination structures,a series of MOFs containing halogen-coordinated copper nodes(Cu-X MOFs,X=Cl,Br,I)are employed to elucidate their structure–activity relationship.Intriguingly,experimental and theoretical results strongly support that precisely tuning the coordination of halogen atoms directly regulates the enzyme-like activities of Cu-X MOFs by influencing the spatial configuration and electronic structure of the Cu active center.The optimal Cu–Cl MOF exhibits excellent superoxide dismutase-like activity with a specific activity one order of magnitude higher than the reported Cu-based nanozymes.More importantly,by performing enzyme-mimicking catalysis,the Cu–Cl MOF nanozyme can significantly scavenge reactive oxygen species and alleviate oxidative stress,thus effectively relieving ocular chemical burns.Mechanistically,the antioxidant and antiapoptotic properties of Cu–Cl MOF are achieved by regulating the NRF2 and JNK or P38 MAPK pathways.Our work provides a novel way to refine MOF nanozymes by directly engineering the coordination microenvironment and,more significantly,demonstrating their potential therapeutic effect in ophthalmic disease.

Decreasing incidence of cutaneous chemical burns in a resource limited burn centre: is this a positive effect of modernization?

Background: Burns present a devastating injury to patients. Burns caused by chemical agents, present a worse scenario. In a resource limited country like Nigeria, readily available sources of these corrosive agents are mainly from lead-acid battery vendors and to some extent local small scale soap manufacturers who use caustic soda. We hypothesized that with the reduction in small scale soap manufacturing and increasing trend towards modernization in the use of dry cell batteries, chemical burns may be on the decline, and we sought to investigate this. Methods: The records of all acute burn patients seen at the Burns and Plastic Department of the National Orthopaedic Hospital Enugu Nigeria between January 2011 and December 2014 were retrospectively reviewed. The results were compared to similar studies carried out at the same centre. A questionnaire was administered to corrosive chemical (sulphuric and caustic soda) vendors to assess the trends in product sales and use in recent times. Results: A total of 624 acute burn cases were treated during the period;among which, 12 cases (1.9%) were chemical burns. When compared with previous studies at the centre, Chemical burn cases were recorded as the lowest rate. The median age of patients was 24 years. There were eight males and four females. Interpersonal assault was the commonest mechanism of injury with sulphuric acid suspected to be the commonest agent in 83.3% of the cases, while 16.7% of the cases were from accidental use of caustic soda. The head and neck as well as the upper limbs were the most affected (30%). Twenty-six questionnaires to lead-acid vendors were analyzed and revealed that all respondents noticed a marked downward trend in the sale of either sulphuric acid or caustic soda, and they attributed this to the ready availability of imported alternatives to locally manufactured soap or wet lead-acid batteries. Ease of use, durability and convenience of the dry cell batteries were cited as principal reasons. Conclusion: There appears to be a downward trend in the prevalence of chemical burns in our study compared to previous studies in the centre which may be due to reduced availability and access of corrosive chemicals to the general public. Further prospective multicentre studies to confirm this are recommended.

Physical and chemical effects of phosphorus-containing compounds on laminar premixed flame

Phosphorus-containing compounds are the promising halon alternatives for flame inhibitions. However, some literatures suggested that the phosphorus-related inhibitors may behave as the unfavorable ones that will increase the burning velocity under lean-burn conditions, and this indeed posed potential threats to the fire prevention and fighting. To seek deeper insights into the reaction process, a numerical investigation was actualized to study the phosphorus-related effects on methane-air flames. By replacing a phosphorus-related inhibitor with the corresponding decomposed molecules, the detailed promoting and inhibiting effects of combustion were separated from the general chemical effect. A comparative study was carried out to identify the interaction between the two effects under different combustion conditions. It is observed that the promoting effect becomes the dominant factor during the reaction process when the equivalence ratio is smaller than 0.60. In this lean-burn condition, the exothermic reactions were faster than the others within the reaction chains due to the reduction of radical recombination in hydrocarbon oxidation. The results are believed to be useful for the further application and improvement of flame inhibitors.

Application of transient burning rate model of solid propellant in electrothermal-chemical launch simulation

A 30 mm electrothermal-chemical(ETC) gun experimental system is employed to research the burning rate characteristics of 4/7 high-nitrogen solid propellant. Enhanced gas generation rates(EGGR) of propellants during and after electrical discharges are verified in the experiments. A modified 0D internal ballistic model is established to simulate the ETC launch. According to the measured pressure and electrical parameters, a transient burning rate law including the influence of EGGR coefficient by electric power and pressure gradient(dp/dt) is added into the model. The EGGR coefficient of 4/7 high-nitrogen solid propellant is equal to 0.005 MW-1. Both simulated breech pressure and projectile muzzle velocity accord with the experimental results well. Compared with Woodley's modified burning rate law, the breech pressure curves acquired by the transient burning rate law are more consistent with test results. Based on the parameters calculated in the model, the relationship among propellant burning rate, pressure gradient(dp/dt) and electric power is analyzed. Depending on the transient burning rate law and experimental data, the burning of solid propellant under the condition of plasma is described more accurately.

Chemical Characterization of PM10 Particulate Matter in the Ambient Air of a Region of Central Italy (Umbria)

Atmospheric particulate matter is a critical factor for many regional urban areas of Umbria (Central Italy region). During 2013 the monitoring air quality network, managed by ARPA Umbria, has been upgraded to Legislative Decree of 13 August 2010, n.155 and an analytical study about chemical composition of PM10 (Particulate Matter with diameter of 10 micrometres or less) over all the region has been started. The PM10 filters have been analyzed for Benzo(α)Pyrene, Pb, Cr, Ni and Cd to check compliance with limits or target values defined in Italian regulation (Legislative Decree of 13 August 2010, n.155);other parameters, like US-EPA list Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzo Furans (PCDD/ Fs), Polychlorinated Biphenyls (PCBs), Organic Carbon/Elemental Carbon (OC/EC) and Levoglucosan were analyzed because they are toxic or because they identify particular pollutant sources. The data obtained showed a large and diffusive biomass burning contribution, widely used in the Umbria Region both for domestic heating in traditional fireplaces and for combustion of pruning residues. In particular the urban sites of Terni and suburban site near Terni (Narni), both lying in the Terni basin called “Conca Ternana”, showed a chemical composition of PM10 that suggests a very large anthropization. This area is the principal industrial reality in the Central Italy because there is a steel production plant, a Municipal solid waste (MSW) burning plant and a chemical plant.

常见化学烧伤的救治方法

随着新化工产品的不断涌现,化学烧伤在工作中发生率明显升高,化学烧伤的损伤一般发生在工作环境中,严重程度和化学品的性质、剂量、浓度、接触时间和接触面积、急救措施等有着密切的关系。目前较多医疗机构内缺乏化学烧伤救治的标准操作流程,本文通过介绍常见局部化学烧伤的处理的基本原则,为临床治疗提供参考。

火烧迹地恢复后不同稳定机制土壤有机碳库特征研究

以大兴安岭重度火烧迹地经过不同方式恢复的林分土壤为研究对象,采用物理-化学联合分组方法,研究未保护、物理保护、化学保护、生物化学保护、物理-化学保护和物理-生物化学保护有机碳组分含量特征及其与土壤总有机碳含量间的关系。结果表明,1)人工恢复的林分土壤总有机碳、未保护有机碳、物理保护有机碳、物理-化学保护有机碳、物理-生物化学保护有机碳和生物化学保护有机碳含量均显著高于自然恢复。化学保护有机碳含量在不同恢复方式下变化不显著。除化学保护有机碳和物理-化学保护有机碳外,其余各保护态有机碳均表现为上层土壤含量显著高于下层(P<0.05)。2)2种恢复方式下的土壤有机碳组分均以未保护有机碳占比最高,物理-化学保护有机碳占比最低。与天然恢复相比,人工恢复下的土壤物理保护有机碳含量占比显著提高2.80%~3.19%(P<0.05)。3)回归分析表明,除物理-化学保护有机碳和化学保护有机碳组分外,其余各保护态有机碳组分与总有机碳含量之间均呈极显著的正相关关系(P<0.001)。大兴安岭重度火烧迹地经过32 a的人工恢复,更利于土壤总有机碳积累,土壤未保护有机碳的积累更多。研究结果为该区域重度火烧迹地植被恢复提供科学依据。

2023年春节期间宿迁市PM_(2.5)化学组分特征与来源解析

2023年春节期间(1月18日—25日),宿迁市发生了一次短时PM_(2.5)重度污染,利用宿迁市环境空气国控监测站、大气超级站、在线单颗粒气溶胶质谱仪等对PM_(2.5)化学组分进行分析,对颗粒物的主要组分进行来源解析,探讨燃放烟花爆竹对空气质量的影响。结果表明,春节期间整体空气质量良好,峰值出现在21日22时—22日0时(除夕夜),PM_(2.5)浓度范围为165~206μg/m^(3),达到重度污染水平,各项化学组分抬升明显,二次有机物占比明显抬升。烟花爆竹燃放指征重金属元素在除夕夜前后变化幅度较大,PM_(2.5)小时均值同步上升3.0倍,K^(+)和Cl^(-)浓度多次出现同时突升,重金属元素和离子元素双重佐证了烟花爆竹燃放助推了颗粒物浓度高值。由于烟花燃放特征离子与本地扬尘源特征离子存在共性(Al^(+)、Ba^(+)、Mg^(+)等矿物质成分),在不利气象条件下主要表现为扬尘源对大气颗粒物贡献率的增加。

高压氧对大鼠深Ⅱ度复合性烧伤创面的促愈作用

目的探讨高压氧对深Ⅱ度复合性烧伤创面的影响及其可能机制。方法50只Wistar大鼠为实验动物,建立深Ⅱ度复合性烧伤模型后,随机分为3组,单纯植皮组(实验组)、植皮配合高压氧治疗组(治疗组)及对照组,分别于伤后第3天行切痂自体皮片移植术,术后加压包扎固定。治疗组治疗给氧压为0.1MPa,一级导管给氧,升压18min,给压60min,减压18min,每日1次,共治疗7次。于伤后10、14、18、24、31天时相点对创面组织形态改变、微血管密度及成纤维细胞超微结构变化、表皮细胞增殖情况进行检测。结果高压氧治疗可使创面愈合时间缩短3～5天,促进肉芽组织的形成(P<0.05),加速成纤维细胞的生长,加速上皮细胞的DNA复制,瘢痕质地软而光滑。结论复合性烧伤后在单纯植皮基础上辅助高压氧治疗,皮片生长及成活情况良好,创面愈合时间快,感染率明显降低,治疗组的修复早于实验组和对照组,瘢痕形成减少,提示该治疗方法在西部高海拔地区临床外科中的推广应用,能缩短患者住院时间,愈后并发症轻,且方法简便易行,治疗效果满意。

秸秆燃烧产生颗粒物化学组分及排放特征

收集玉米、水稻和小麦秸秆模拟露天燃烧排放的颗粒物,分析样品中碳质组分、水溶性离子(共9种)和无机元素(共17种),研究其排放因子及特征比值。结果表明:秸秆燃烧OC的排放因子远高于EC,二者范围分别为169~1 707和91~300 mg/kg。总水溶性离子排放因子范围为162~840 mg/kg。K^+、Na^+、NH_4^+和Cl^-是水溶性离子的主要组分,占水溶性离子总排放因子的80%~92%。K、Ca、P和Mg 4种生长元素排放因子之和占秸秆燃烧排放颗粒物中无机元素的98%~99%。Zn、Pb、Cu为秸秆燃烧排放颗粒物中排放因子较高的重金属元素,这些重金属对人体健康的影响不可忽视。此外,研究发现OC/EC可以用来区分秸秆燃烧与香烟燃烧、重型柴油车和草类燃烧源,K^+/OC可以用来区分秸秆燃烧与居民燃木取暖,K/Ca可以用来区分秸秆燃烧与交通污染源。

碱性成纤维细胞生长因子促进角膜碱烧伤上皮修复的实验研究

120只兔角膜碱烧伤眼随机分成5组，分别以3种不同剂量的bFGF滴眼液和素高捷疗滴眼治疗，荧光素染色裂隙灯照相，照片经计算机图象系统分析，并做形态学检查。结果表明bFGF滴服液能促进角膜上皮的愈合。

中度火干扰对白桦落叶松混交林土壤理化性质的影响

应用空间代替时间的方法对大兴安岭林区白桦落叶松混交林1982—2007年的中度火烧迹地土壤理化性质变化进行研究。结果表明:火后土壤密度增加,土壤孔隙度和土壤含水率降低,但是变化幅度将随着时间的推移逐渐缩小,并在火烧后第20年将接近火烧前水平;火烧后A层和B层土壤有机质均呈降低趋势,A层的降幅逐渐缩小直到火烧后20年比火烧前水平大幅增加;火后土壤A层和B层全磷含量均呈增加趋势,土壤全氮在A层基本也呈增加趋势,B层随火后时间呈波动变化,无明显规律;土壤有效磷含量变化呈先降低后增加的趋势;A层土壤速效钾含量的变化基本呈增加趋势,但随时间增加幅度减小,而B层的变化无规律;A层土壤水解氮含量变化呈增加趋势,而B层的变化则与速效钾在B层的变化相似,无明显规律。此研究旨在找出火烧后随时间的推移土壤理化性质的动态变化规律,为火烧迹地的改造和生态恢复提供科学依据。

2014年10月上旬北京市大气重污染分析

使用垂直观测、地面观测和PM2.5化学组分观测等手段,对2014年10月上旬北京市一次重污染过程进行分析.结果表明,本次大气重污染发生时北京市近地面后散射激光强度变强,气溶胶消光系数升高,说明污染物在近地面层积累.重污染期间气象要素特征为:风场弱,湿度大,地面受弱气压场控制.从PM2.5浓度变化趋势来看,这次重污染过程大体分为四个阶段:"两个台阶"型的浓度爬升阶段(P1和P2)、高浓度维持阶段(P3)和迅速清除阶段(P4).结合地面观测、遥感反演和PM2.5组分分析可发现,区域传输是导致本次重污染的诱因,其中秸秆焚烧是影响因素之一,随后区域传输和本地污染物排放共同维持并加重了重污染过程.大气氧化剂OX与PM2.5浓度、二次离子浓度均表现出显著正相关性,表明较强的大气氧化性能促进PM2.5浓度增长.

新型PHEMA一体式人工角膜植入碱烧伤兔角膜的实验研究

目的 研究与评估聚羟乙基丙烯酸甲酯 (PHEMA)制作的一体式人工角膜在碱烧伤角膜中的生物相容性和生物愈合过程 ,并初步观察实验结果。方法 兔角膜碱烧伤 3个月后 ,形成带新生血管的角膜白斑模型。实验分两部分进行。第一部分 ,将孔隙性PHEMA材料植入角膜板层间 ,进行光镜和电镜检查 ,评价其与角膜组织生物愈合的情况。第二部分 ,将周边为多孔结构、中央为透明光学区的PHEMA一体式人工角膜植入碱烧伤兔角膜 ,进行临床试验观察。结果 所有植入物均稳定存留于角膜内 ,实验观察最长达 2 8周 ,未见排出、周围组织溶解、网脱等并发症。组织学提示炎症反应轻微 ,所有标本中均没有钙化出现。PHEMA材料孔隙中 ,2周即有成纤维细胞长入 ,并有胶原沉积 ,16周时 ,材料的大部分孔隙被成纤维细胞和胶原等细胞外基质填充 ,即与角膜组织能形成稳定的连接 ;植入的一体式人工角膜的动物观察结果较满意。结论 用PHEMA制成一体式人工角膜 ,具有良好的生物相容性 ,通过周边孔隙结构可望与碱烧伤的角膜产生“生物愈合” ,并保证植入PHEMA一体式人工角膜的稳固性。

羊膜移植术在碱烧伤急性期重建结膜表面的实验研究(英文)

目的:(1)研究羊膜移植在治疗兔眼大面积结膜碱烧伤,重建健康结膜表面中的作用。(2)探讨碱烧伤急性期施行羊膜移植术的可行性。方法:选用30只家兔,制作角膜缘上方球结膜至穹隆部的碱烧伤的动物模型。实验组于碱烧伤后1wk时(急性期)行保存的人羊膜移植术及穹隆成形术。术后1,2,3,4,8,12wk时做光镜观察移植部位的结膜上皮生长情况,并于术后1,4,8wk时取移植区结膜做电镜观察其超微结构,同时与碱烧伤后行结膜下注射维生素C及应用抗生素眼药水点眼治疗的对照组结膜作对照观察。并在上述相应时期摄眼外观像、做上角膜缘至上方穹隆部宽度的测量。结果:(1)羊膜移植术后1wk时,光镜、电镜可见羊膜上有结膜上皮细胞长入,4wk时,含有杯状细胞的结膜上皮完全覆盖羊膜,接近于正常的结膜组织,12wk时,羊膜上结膜上皮细胞排列整齐,穹隆部结膜上皮下纤维结缔组织较为疏松,无增生。而对照组1wk时见结膜上皮细胞坏死脱落,未见有含杯状细胞的结膜上皮长入,4～8wk时所见为大量纤维结缔组织增生,伴炎性细胞浸润。12wk时,穹隆部纤维结缔组织增生明显,未见有正常结膜上皮覆盖。(2)外观眼表可见,12wk时实验组移植区结膜光滑无瘢痕,上穹隆形成良好,穹隆深达7.6～8.2mm,接近正常穹隆深度8.0～8.5mm。而对照组结膜表面不光滑,有结膜肉芽肿形成,瘢痕增生明显,上方穹隆明显变浅,穹隆深度为1.0～4.5mm。结论:以甘油保存的羊膜可作为一种底物载体,提供健康的基底膜,有利于周围正常结膜上皮的粘附、移行和分化,进而重建正常结膜表面。结膜碱烧伤后早期行羊膜移植可重建正常结膜表面,有效地防止睑球粘连的发生。

自体血清治疗严重眼化学烧伤的临床研究

目的探讨自体血清治疗严重眼化学烧伤的疗效。方法将22例30眼严重眼化学烧伤患者随机分为2组,治疗组11例15眼使用自体血清治疗,对照组11例15眼未加用自体血清,余治疗方法同治疗组,对2组进行临床疗效分析。结果治疗组治愈率80%,有效率100%;对照组治愈率33.3%,有效率93.3%;差异有统计学意义(P<0.05)。治疗组平均疗程比对照组缩短8d,有显著统计学差异(P<0.01)。结论使用自体血清治疗严重眼化学烧伤安全、有效、无毒副作用,值得临床推广应用。

生物质燃烧颗粒物的定量分析和化学形态

用电子探针技术开展单个含钾颗粒物的分析表征 .第一种方法用蒙特卡洛方法模拟电子束与样品复杂的相互作用 ,对于KCl晶粒取得的计算结果与理论值一致 .K/Cl比的均值为 0 996 ,标准偏差为 0 0 1 2 .由于晶形不规则和热稳定性差 ,K2 SO4 和KHSO4 的结果没有达到KCl的准确度 .其K/S比的均值和标准偏差分别为 1 90 5±0 0 1 3和 1 0 1 4± 0 0 72 .第二种方法用回归分析方法处理了同一种类若干数目的颗粒物分析数据 .直接用同种类标准颗粒物的分析结果校准 ,进行定量分析和化学形态识别 .研究结果表明 ,非洲草原大火燃烧排放时 ,含钾颗粒经历了逐步酸化的过程 .在排放时主要以KCl形态存在 ,少量是K2 SO4 和复盐 .在大气传输过程中逐渐酸化 ,主要转变成KHSO4 .少量停空时间长的颗粒则继续酸化 ,成为高度富硫的颗粒 .