Cigar孤立子上加权散度型椭圆算子的特征值估计

本文研究了cigar孤立子(R 2,g,f)上加权散度型椭圆算子LA,f的如下Dirichlet特征值问题:{LA,f u+V u=λρu,inΩ,u=0,on∂Ω,其中V和ρ分别是Ω上的非负连续函数和正连续函数.我们建立了该问题的一些特征值不等式.

Evidence relating cigarettes,cigars and pipes to cardiovascular disease and stroke:Meta-analysis of recent data from three regions

BACKGROUND More recent data are required relating to disease risk for use of various smoked products and of other products containing nicotine.Earlier we published metaanalyses of recent results for chronic obstructive pulmonary disease and lung cancer on the relative risk(RR)of current compared to never product use for cigarettes,cigars and pipes based on evidence from North America,Europe and Japan.We now report corresponding up-to-date evidence for acute myocardial infarction(AMI),ischaemic heart disease(IHD)and stroke.AIM To estimate,using recent data,AMI,IHD and stroke RRs by region for current smoking of cigarettes,cigars and pipes.METHODS Publications in English from 2015 to 2020 were considered that,based on epidemiological studies in the three regions,estimated the current smoking RR of AMI,IHD or stroke for one or more of the three products.The studies should involve at least 100 cases of stroke or cardiovascular disease(CVD),not be restricted to populations with specific medical conditions,and should be of cohort or nested case-control study design or randomized controlled trials.A literature search was conducted on MEDLINE,examining titles and abstracts initially,and then full texts.Additional papers were sought from reference lists of selected papers,reviews and meta-analyses.For each study identified,we entered the most recent available data on current smoking of each product,as well as the characteristics of the study and the RR estimates.Combined RR estimates were derived using random-effects meta-analysis for stroke and,in the case of CVD,separately for IHD and AMI.For cigarette smoking,where far more data were available,heterogeneity was studied by a wide range of factors.For cigar and pipe smoking,a more limited heterogeneity analysis was carried out.A more limited assessment of variation in risk by daily number of cigarettes smoked was also conducted.RESULTS Current cigarette smoking:Ten studies gave a random-effects RR for AMI of 2.72[95%confidence interval(CI):2.40-3.08],derived from 13 estimates between 1.47 and 4.72.Twenty-three studies gave an IHD RR of 2.01(95%CI:1.84-2.21),using 28 estimates between 0.81 and 4.30.Thirty-one studies gave a stroke RR of 1.62(95%CI:1.48-1.77),using 37 estimates from 0.66 to 2.91.Though heterogeneous,only two of the overall 78 RRs were below 1.0,71 significantly(P<0.05)exceeding 1.0.The heterogeneity was only partly explicable by the factors studied.Estimates were generally higher for females and for later-starting studies.They were significantly higher for North America than Europe for AMI,but not the other diseases.For stroke,the only endpoint with multiple Japanese studies,RRs were lower there than for Western studies.Adjustment for multiple factors tended to increase RRs.Our RR estimates and the variations by sex and region are consistent with earlier meta-analyses.RRs generally increased with amount smoked.Current cigar and pipe smoking:No AMI data were available.One North American study reported reduced IHD risk for non-exclusive cigar or pipe smoking,but considered few cases.Two North American studies found no increased stroke risk with exclusive cigar smoking,one reporting reduced risk for exclusive pipe smoking(RR 0.24,95%CI:0.06-0.91).The cigar results agree with an earlier review showing no clear risk increase for IHD or stroke.CONCLUSION Current cigarette smoking increases risk of AMI,IHD and stroke,RRs being 2.72,2.01 and 1.62.The stroke risk is lower in Japan,no increase was seen for cigars/pipes.

Evidence relating cigarette,cigar and pipe smoking to lung cancer and chronic obstructive pulmonary disease:Meta-analysis of recent data from three regions

BACKGROUND There is a need to have up-to-date information for various diseases on the risk related to the use of different smoked products and the use of other nicotinecontaining products.Here,we contribute to the information pool by presenting up-to-date quantitative evidence for North America,Europe and Japan and for both lung cancer and chronic obstructive pulmonary disease(COPD)on the relative risk(RR)relating to current vs never product use for each of the three smoked tobacco products,cigarettes,cigars and pipes.AIM To estimate lung cancer and COPD current smoking RRs for the three products using recent data for the three regions.METHODS Publications in English from 2010 to 2020 were considered that,based on epidemiological studies in the three regions,estimated the current smoking RR of lung cancer and/or COPD for one or more of the three products.The studies should involve at least 100 cases of the disease considered,not be restricted to specific lung cancer types or populations with specific medical conditions,and should be of cohort or nested case-control study design or randomized controlled trials.Literature searches were conducted on MEDLINE separately for lung cancer and for COPD,examining titles and abstracts initially,and then full texts.Additional papers were sought from reference lists of selected papers,reviews and metaanalyses.For each study identified,the most recent available data on each product were entered on current smoking,as well as on characteristics of the study and the RR estimates.Combined RR estimates were derived using random-effects meta-analysis.For cigarette smoking,where far more data were available,heterogeneity was studied by a wide range of factors.For cigar and pipe smoking,a more limited heterogeneity analysis was carried out.Results were compared with those from previous meta-analyses published since 2000.RESULTS Current cigarette smoking:For lung cancer,44 studies(26 North American,14 European,three Japanese,and one in multiple continents),gave an overall estimate of 12.14[95%confidence interval(CI)10.30-14.30].The estimates were higher(heterogeneity P<0.001)for North American(15.15,CI 12.77-17.96)and European studies(12.30,CI 9.77-15.49)than for Japanese studies(3.61,CI 2.87-4.55),consistent with previous evidence of lower RRs for Asia.RRs were higher(P<0.05)for death(14.85,CI 11.99-18.38)than diagnosis(10.82,CI 8.61-13.60).There was some variation(P<0.05)by study population,with higher RRs for international and regional studies than for national studies and studies of specific populations.RRs were higher in males,as previously reported,the within-study male/female ratio of RRs being 1.52(CI 1.20-1.92).RRs did not vary significantly(P≥0.05)by other factors.For COPD,RR estimates were provided by 18 studies(10 North American,seven European,and one Japanese).The overall estimate of 9.19(CI 6.97-12.13),was based on heterogeneous data(P<0.001),and higher than reported earlier.There was no(P>0.1)variation by sex,region or exclusive use,but limited evidence(0.05<P<0.1)that RR estimates were greater where cases occurring shortly after baseline were ignored;where bronchiectasis was excluded from the COPD definition;and with greater confounder adjustment.Within-study comparisons showed adjusted RRs exceeded unadjusted RRs.Current cigar smoking:Three studies gave an overall lung cancer RR of 2.73(CI 2.36-3.15),with no heterogeneity,lower than the 4.67(CI 3.49-6.25)reported in an earlier review.Only one study gave COPD results,the RR(2.44,CI 0.98-6.05)being imprecise.Current pipe smoking:Four studies gave an overall lung cancer RR of 4.93(CI 1.97-12.32),close to the 5.20(CI 3.50-7.73)given earlier.However,the estimates were heterogeneous,with two above 10,and two below 3.Only one study gave COPD results,the RR(1.12,CI 0.29-4.40),being imprecise.For both diseases,the lower RR estimates for cigars and for pipes than for current smoking of cigarettes aligns with earlier published evidence.CONCLUSION Current cigarette smoking substantially increases lung cancer and COPD risk,more so in North America and Europe than Japan.Limited evidence confirms lower risks for cigars and pipes than cigarettes.

Carbon footprint accounting for cigar production processes: A life cycle assessment perspective

Although the tobacco industry is a significant contributor to energy consumption and carbon emissions its negative environmental impact has received inadequate attention globally.Cigarette factories are a key link in the tobacco industry’s production chain,and using data provided by a cigarette factory in China we conduct a life cycle assessment to account for the carbon footprint of cigar production in cigarette factories.The results of the assessment show that factory air conditioning is the most important contributor to the environmental load of the cigar manufacturing process,while electricity is the key factor that contributes the greatest envi‐ronmental load across all of the processes in the product life cycle.In addition,packaging,including small boxes and cigarette cartons,has a significant impact on the industry’s environmental footprint due to its use of raw materials.We find the carbon footprint of the entire production process for cigar products to be 383.59 kg CO_(2) eq.Based on our findings,we suggest ways to optimize cigar/cigarette factory processes to re‐duce carbon emissions that can help to promote sustainable development in related industries.

距离Cigar域与拟共形映射

设f:Rn→Rn是一同胚,本文证明了f是拟共形映射的充要条件是f将Rn中的任一距离Cigar域映成Rn中的距离Cigar域.

The Function of Cigar in Blackmail

This thesis intends to use the symbolic structure of cigar to analyze the extract Blackmail from Arthur Hailey's short novel Hotel.The function of cigar in Blackmail can be concluded as a) constructive clue of the plot progression,b) genteel carrier in making up characters.Rotating around the constructive clue,cigar,the writer of this thesis breaks down the whole story into seven parts,i.e.mystical entrance,prelude,crossfire,preparatory victory,absolute superiority,negotiation (absence of cigar) and discard.As to cigar's function of making up character,this thesis examines it from four main social and historical aspects,i.e.the origin of cigar in history,the social token of cigar,the complicated approaches of using cigar,and the historical stereotypes related to cigar smoking.

Effects of Altitude on Polyphenols Contents in Cigar Leaves

Elevation affects the contents of polyphenols involved in the plants’resistance to the environment.In this study,polyphenolic contents,as well as the activity of polyphenol oxidase(PPO),were evaluated in mature cigar plants at different elevation levels.The results showed that:(1)The contents of chlorogenic acid,rutin,and scopolamine in cigar leaves increased gradually at all elevation levels,reaching a maximum 25 d after the mature stage.(2)With an increase in altitude,the polyphenolic compounds’contents increased,having the lowest values at 350 m height and the highest at 1090 m height.(3)As for the PPO activity in cigar leaves,the general trend showed an increase first followed by a decrease in activity during the mature period.(4)PPO activity in the leaves of cigar plants planted at 840 m height was substantially elevated compared to those growing at 600 m and 350 m height.Interestingly,the leaves planted at 1090 m height had the lowest PPO activity.(5)There were significant positive correlations between altitude and the contents of chlorogenic acid,rutin,and scopolamine within the plants leaves.Altitude negatively correlated the proportion of chlorogenic acid and scopolamine whereas positively correlated rutin proportion within the total polyphenols.Temperature had negative correlations with the contents of chlorogenic acid,rutin,and scopolamine,while sunlight intensity had positive correlations on their contents.Conversely,there were no significant correlations between altitude,temperature,and light intensity on PPO activity.Therefore,this study can provide valuable insight and a theoretical basis for the production of premium cigars.

Exclusive cigar smoking in the United States and smoking-related diseases: A systematic review

BACKGROUND Little information has been published on the risks of cigar smoking.Since 1990 cigar smoking has become more prevalent in the United States.AIM To summarise the evidence from the United States relating exclusive cigar smoking to risk of the major smoking-related diseases.METHODS Literature searches detected studies carried out in the United States which estimated the risk of lung cancer,chronic obstructive pulmonary disease(COPD),heart disease,stroke or overall circulatory disease in exclusive cigar smokers as compared to those who had never smoked any tobacco product.Papers were identified from reviews and detailed searches on MEDLINE.For each study,data were extracted onto a study database and a linked relative risk database.Relative risks and 95%CIs were extracted,or estimated,relating to current,former or ever exclusive cigar smokers,and meta-analysed using standard methods.Sensitivity analyses were conducted including or excluding results from studies that did not quite fit the full selection criteria(for example,a paper presenting combined results from five studies,where 86%of the population were in the United States).RESULTS The literature searches identified 17 relevant publications for lung cancer,four for COPD and 12 for heart disease,stroke and circulatory disease.These related to 11 studies for lung cancer,to four studies for COPD and to eight studies for heart disease,stroke or overall circulatory disease.As some studies provided results for more than one disease,the total number of studies considered was 13,with results from four of these used in sensitivity analyses.There was evidence of significant heterogeneity in some of the meta-analyses so the random-effects estimates are summarized below.As the results from the sensitivity analyses were generally very similar to those from the main analyses,and involved more data,only the sensitivity results are summarized below.For lung cancer,relative risks(95%CI)for current,former and ever smokers were respectively,2.98(2.08 to 4.26),1.61(1.23 to 2.09),and 2.22(1.79 to 2.74)based on 6,4 and 10 individual study estimates.For COPD,the corresponding estimates were 1.44(1.16 to 1.77),0.47(0.02 to 9.88),and 0.86(0.48 to 1.54)based on 4,2 and 2 estimates.For ischaemic heart disease(IHD)the estimates were 1.11(1.04 to 1.19),1.26(1.03 to 1.53)and 1.15(1.08 to 1.23)based on 6,3 and 4 estimates,while for stroke they were 1.02(0.92 to 1.13),1.08(0.85 to 1.38),and 1.11(0.95 to 1.31)based on 5,3 and 4 estimates.For overall circulatory disease they were 1.10(1.05 to 1.16),1.11(0.84 to 1.46),and 1.15(1.06 to 1.26)based on 3,3 and 4 estimates.CONCLUSION Exclusive cigar smoking is associated with an increased risk of lung cancer,and less so with COPD and IHD.The increases are lower than for cigarettes.

拟共形映射和弱Cigar域

设f是R^n到R^n上的同胚,本文证明了f是拟共形映射的充要条件是f将R^n中的任一弱Cigar域映成R^n中的弱Cigar域。

茄衣新品系川雪2号全国多点试验研究

为雪茄烟茄衣新品系川雪2号的品种审定、推广提供科学依据。以川雪2号及其他8份雪茄烟品系为试验材料,2021年在全国9个主要雪茄烟产区、2022年在全国8个主要雪茄烟产区开展多点试验。结果表明,川雪2号田间整齐、长势强,大田生育期88 d、免疫TMV、抗根黑腐病、综合抗病能力较强、田间自然发病率整体较轻;平均产量为1533.30 kg/hm^(2),平均产值为83234.70元/hm^(2),中上等烟比例为74.98%,产量、产值、中上等烟比例、评吸总分等在9个参试品系中排名靠前。川雪2号总体表现较好,可以进行一定规模的示范种植并开展相关配套栽培技术研究。

基于改进组合赋权法和VIKOR法的茄芯烟叶化学品质评价

[目的]探讨改进组合赋权法与多准则妥协解排序法(VIKOR)相结合开展茄芯化学品质评价,以期丰富雪茄烟叶质量评价方法。[方法]以云南茄芯烟叶化学成分为研究对象,引入变异系数和复相关系数改进传统CRITIC法(Criteria importance through inter-criteria correlation),采用e^(0/4)~e^(8/4)标度取代层次分析法(Analytic hierarchy process,AHP)中的1~9标度,并基于博弈论计算组合权重,利用无权重个体遗憾值改进的VIKOR法开展茄芯化学品质评价。[结果]与传统CRITIC法确定的化学成分指标权重相比,改进CRITIC法中钾的权重提升1.09倍,还原糖指标权重降低45.26%;e^(0/4)~e^(8/4)标度与1~9标度AHP法确权结果相比,权重大小排序一致,不同化学成分指标间权重的差异减小;改进VIKOR法与传统方法对茄芯化学品质的排序结果具有较高的一致性,但也存在不可忽略的差异,说明有必要在个体遗憾值中考虑权重的影响。[结论]改进CRITIC法能够解决传统方法确权受计量单位和正负向指标影响的问题,AHP法中通过标度的替代显著提升判断矩阵的一致性,无权重个体遗憾值条件下的VIKOR法在综合考虑化学品质整体表现的同时,突显了表现较差的化学成分指标的作用,评价结果相对合理。

莫海威芽孢杆菌(Bacillus mojavensis)ZLX10对发酵雪茄烟叶中性致香成分的影响

为探究烟草源微生物单菌发酵对雪茄烟叶挥发性致香成分的影响,采用GC-MS检测莫海威芽孢杆菌(Bacillus mojavensis)ZLX10发酵雪茄烟叶中性致香成分,筛选差异致香成分,并与感官评价进行相关性分析,结合ROAV值变化,明确ZLX10提升雪茄烟叶感官品质的关键致香成分。结果表明,ZLX10发酵雪茄烟叶后,香气总量和大多数中性致香成分含量均显著提高,共筛选得到15种差异中性致香成分,共有10种致香成分显著上调(P<0.05),其中巨豆三烯酮A、巨豆三烯酮B、6-甲基-5-庚烯-2-酮、2,6,6-三甲基-2-环己烯-1,4-二酮、茄酮和植物醇与烟叶香气呈显著正相关(P<0.05),可认为是增加烟叶干香和花香的关键差异致香成分;共有5种致香成分显著下调(P<0.05),其中苯乙醛和2,4-二叔丁基-6-硝基苯酚与烟叶刺激性呈显著正相关(P<0.05),对烟叶香气有较大的负面影响。由此可知,ZLX10发酵能促进雪茄烟叶香气质和香气量得到提升,这为人工接菌发酵雪茄烟叶提供了基础。

雪茄烟新品种雪雅香1号的选育及特征特性

【目的】选育适合国内种植的优质抗病雪茄烟茄衣新品种。【方法】以优质雪茄烟品种M6的雄性不育系(MSM6)为母本,抗病性强且产量较高的J20为父本,杂交选育了雄性不育一代杂交种雪雅香1号。【结果】该品种田间生长势强,生长整齐一致;抗病性表现较好,对烟草普通花叶病毒病(Tobacco mosaic virus, TMV)免疫,中抗黑胫病,中抗~抗青枯病,抗根黑腐病;烟叶主要经济性状表现较好,化学成分比例较协调,外观质量、物理特性符合优质茄衣的要求;雪茄烟风格较显著,香气量和香气质的表现较好。【结论】雪雅香1号是我国自主选育的雪茄烟新品种,能够兼顾品质、经济和抗病性,烟叶质量可以满足中式茄衣的需求,适宜在四川烟区、湖北烟区及国内其他同类烟区种植。

雪茄茄芯和茄衣烟叶不同区段化学成分和品质差异性分析

为明确雪茄烟叶不同区段的品质差异,以雪茄品种德雪1号发酵后分拣出的一等茄衣和茄芯烟叶为材料,对叶基至叶尖5个不同区段的常规化学成分、中性香气成分、烟草特有亚硝胺(TSNAs)及前体物含量进行测定,并进行感官评吸鉴定。结果表明,雪茄烟叶不同区段化学成分差异显著,还原糖、总糖含量在叶尖和近叶尖区段相对较高,总氮和蛋白质含量在近叶基区段较高,烟碱含量自叶基到叶尖先升高后降低。茄芯、茄衣烟叶的中性香气成分含量从叶基至叶尖均先增加后减少,其中茄芯烟叶在叶中区段最高,茄衣在近叶基区段最高。2种类型雪茄烟叶的TSNAs含量从叶基至叶尖均持续下降,但降幅不同,茄芯、茄衣烟叶叶尖较叶基分别下降68.25%、30.19%。除刺激性外,2种烟叶的6项感官质量指标得分及总分从叶基至叶尖均表现为先升高后降低,以叶中和近叶尖区段较优。综上,雪茄烟叶以叶中和近叶尖区段香气浓郁,有害成分低,评吸质量较好。

遮阴栽培对雪茄茄衣烟叶叶面均匀性的影响

为探究遮阴栽培对雪茄茄衣品种叶面均匀性的影响,以雪茄茄衣品种‘楚雪26号’(CX-26)为研究对象,在大田试验条件下进行不同程度的遮阴处理,分析其成熟期上部叶和中部叶的叶面厚度、叶面平展度、叶片密度、主支脉粗细、主支脉占叶片干物质量比例以及SPAD值等的差异。结果表明,随着遮阴程度的增加,上部叶的叶面厚度、叶片密度以及叶片SPAD值均逐渐下降;当透光率为70%时,叶面厚度、叶片密度与不遮阴处理相比分别下降35.5%和33.3%,而中部叶中各性状则逐渐上升。遮阴栽培显著增加上部叶的叶面平展度,但降低了中部叶的叶面平展度;在透光率为70%时,上部叶的叶面平展度达到最大,为0.98;遮阴栽培增加上部叶主支脉占叶片干物质量比例,对中部叶主支脉占叶片干物质量比例的影响随遮阴程度的增加呈下降趋势,但差异不显著。遮阴栽培对中部叶主支脉的粗细程度无影响,但使上部叶的主支脉变细。以上研究结果为国产雪茄茄衣烟叶遮阴栽培技术提供理论基础。

雪茄烟叶工业发酵过程中霉变对真菌群落结构的影响研究

为探究雪茄烟叶工业发酵过程中真菌群落结构随霉变发生的变化情况,以德雪一号雪茄烟叶为实验材料,采用微生物学计数方法和Illumina MiSeq高通量测序技术对雪茄烟叶工业发酵过程中正常烟叶和霉变烟叶进行霉菌数量及真菌群落结构变化分析。结果表明:与正常烟叶相比,发酵第30 d霉变雪茄烟叶中,霉菌数量最高(8.3×10^(4) CFU/g),物种丰富度和多样性最低,OTU数量最少;在门水平上,子囊菌门(Ascomycota)在发酵第30 d霉变烟叶中为绝对优势菌门,平均相对丰度为99.82%;在属水平上,曲霉属(Aspergillus)为整个发酵过程中的主要优势菌属,在发酵第30 d霉变雪茄烟叶中平均相对丰度最大(92.32%);发酵第30 d霉变雪茄烟叶与正常烟叶相比在物种组成上具有明显差别,其中曲霉属既是优势菌属,又是组间差异菌属,且在各样品中平均相对丰度均最高,推断其为引起雪茄霉变发生的关键菌属。

^(60)Co-γ射线辐照对雪茄烟叶发酵微生物和代谢物变化及烟叶质量的影响

【目的】通过^(60)Co-γ射线辐照灭菌,明确微生物在雪茄烟叶发酵过程中的重要作用。【方法】以四川雪茄烟品种德雪1号为试验材料,以剂量10 kGy的^(60)Co-γ射线对发酵前烟叶进行辐照处理,测定分析发酵过程中烟叶微生物多样性、代谢组学、中性香气成分和常规化学成分含量。【结果】(1)辐照组烟叶发酵28 d样本经传统分离培养和Illumina MiSeq高通量测序均未发现细菌群落。(2)非靶向代谢组学结果显示,辐照组烟叶发酵28 d后芸香苷、根皮苷和山奈酚等多酚类物质,山奈酚-3-O-芸香糖苷等多酚糖苷类物质,二肽等含量高于未辐照组烟叶,而亮氨酸、L-丝氨酸和脯氨酸等氨基酸含量低于未辐照烟叶。KEGG富集差异显著的代谢通路是黄酮和黄酮醇生物合成通路与花生四烯酸代谢通路。(3)发酵28 d后,两组烟叶的生物碱、还原糖、总糖、淀粉和蛋白质含量均显著降低,辐照组烟叶发酵前后各指标的降幅小于未辐照烟叶。辐照组烟叶发酵28 d后中性香气成分总量显著低于未辐照烟叶,而棕色化反应产物总量显著增加,烟叶劲头、杂气、刺激性更大。【结论】对发酵前烟叶进行10 kGy^(60)Co-γ射线辐照可有效杀灭烟叶细菌,发酵28 d后大分子物质降解转化低于未辐照烟叶,感官质量增加幅度减小,但相比于发酵前仍有一定程度的改善。

两种雪茄烟分段烟气香气成分及香气特征差异分析

为探究雪茄烟前、中、后3段烟气的差异性,采用气相色谱-质谱联用技术(GC-MS)对长城2号和蒙特4号两种雪茄烟分段烟气香气成分进行检测,结合感官评价和气味贡献权重对雪茄烟香气特征进行研究,并基于偏最小二乘判别分析(PLS-DA)法筛选雪茄烟中关键差异香气成分。结果表明:抽吸过程中烟支变短、截留效果减弱,雪茄烟烟气中香气成分的数量和释放量整体呈增加趋势;在雪茄烟气味贡献权重中,随着抽吸的进行,长城2号的豆香和木香减弱、咖啡香增强,蒙特4号的豆香减弱、辛香增强,这些气味的权重变化与感官评价结果具有一致性;长城2号中引起香气特征变化的有γ-己内酯、糠酸、苯乙酮、苯乙酸、2,6-二甲基吡嗪等12个关键差异香气成分,蒙特4号中引起香气特征变化的有雪松醇、2-甲基丁醛、4-乙烯基愈创木酚、愈创木酚、γ-壬内酯等11个关键差异香气成分。该研究结果反映了雪茄烟抽吸过程中烟气成分变化规律,并解释了抽吸过程中风味变化的原因。

基于随机森林特征优选的雪茄烟叶晾制过程含水率预测

针对雪茄烟叶晾制过程含水率人工判断主观性强、准确度低等不足,以及对影响雪茄烟叶晾制过程含水率预测的重要表观特征尚不明确等问题,该研究基于图像特征提取以及机器学习技术实现雪茄烟叶晾制过程含水率的预测。试验以雪茄烟品种“云雪2号”为试验材料,获取晾制过程的烟叶图像的颜色、轮廓、纹理以及部位四类特征并筛选出雪茄烟叶含水率预测的优选图像特征子集。在此基础上,构建了随机森林(random forest,RF)、支持向量机(support vector regression,SVR)与反向传播神经网络(back propagation neural network,BPNN)模型,并利用遗传算法(genetic algorithm,GA)对各模型超参数进行优化,将原始图像特征集与优选图像特征集输入3个机器学习模型,构建出6种模型-特征组合方案,依据晾制时期对原始数据集进行划分,并对测试集进行预测。最终结果显示:GA-SVR模型+优选图像特征子集的组合方案在测试集上表现最优,其决定系数(coefficient of determination,r^(2))与均方误差(mean square error,MSE)分别为0.980和0.001,且运行时间最短(运行时长为0.128 s)。研究结果可为雪茄烟叶晾制过程智能化控制提供理论依据。

夏冬两季发酵雪茄烟叶的代谢组差异分析

【目的】解析夏冬季节发酵的雪茄烟叶代谢物差异。【方法】采用超高效液相色谱串联质谱(UPLC-MS/MS)技术对发酵前、冬季发酵、夏季发酵的雪茄烟叶样品进行广泛靶向代谢物检测。【结果】发酵期间(历时34 d)夏季、冬季发酵房平均温度分别是27.2℃、14.7℃,二者相差12.5℃,平均湿度分别是77.6%、66.7%,二者相差10.9%,夏季更符合烟叶发酵相对高温、高湿的环境要求;雪茄烟叶样品检测得到905种代谢物包含10类:生物碱、酚酸、黄酮、脂质、氨基酸、有机酸、萜类、糖类、核苷酸、木质素,其中生物碱、有机酸、脂质含量比例居前三,分别是24.5%、23.7%、15.0%。烟叶发酵后,有机酸、脂质、氨基酸、酚酸的含量都显著提升,生物碱、萜类、黄酮、糖类、木质素的含量有不同程度的减少。夏季发酵的烟叶生物碱、萜类代谢转化更剧烈,有机酸、氨基酸、黄酮、脂质、糖类含量较高,化学成分更协调,香气质量更丰富,烟气柔顺、余味甜润,感官品质更优。【结论】鄂西南地区夏季自然高温高湿环境,更顺应雪茄烟农业发酵理想状态,将当年生产的雪茄烟叶在冬季自然醇化后推迟到次年夏季发酵,或可作为探索推动雪茄烟发酵工序提质增效的参考方案。