基于近红外透射光谱的牛奶中脂肪和蛋白质含量检测

基于近红外光谱检测牛奶中蛋白质和脂肪含量是当前的一个研究热门,主要可以利用近红外反射光谱,近红外漫反射光谱和近红外透射光谱的光谱信息来分析牛奶的主成分含量。本文是利用近红外透射光谱原始数据,通过数学方法转换,从吸光值、吸光比和吸收度三种形式,采用偏最小二乘法(PLS)回归,分别建立了其与牛奶主成分浓度之间的校正模型。对比三种形式所建立的数学模型的优劣,探讨了如何提高PLS校正模型预测精度的相关问题。     

He-Ne激光照射对大鼠神经损伤后自残及神经再生的影响

本实验利用大鼠坐骨神经钳夹损伤模型 ,观察了氦氖 (He -Ne)激光照射 (A组 )、直流电针刺激器 (B组 )、对照组为 (C组 )对神经损伤后自残及神经再生的影响。结果 :( 1)术后 2 0d ,A组的右后足趾自残率为 13 % ,而B、C组分别为 46%、80 % ,A组的自残率显著低于其它各组(P <0 .0 0 1) ;( 2 )右侧屈肌反向阈 :当激光照射时光斑直径 0 .6cm ,功率密度为 3 5 .3 9mW/cm2 时 ,可引出短潜伏期 ( 4 5 -15 0ms)及长潜伏期 ( 12 5 5 2 5ms)传入纤维反应 ;( 3 )术后 2 0d脊神经节的标记细胞百分率分别为 11.1% (A组 )、5 .2 % (B组 )及 1.1% (C组 ) ;脊髓前角的标记细胞百分率分别为 16.6% (A组 )、8.1% (B组 )及 1.9% (C组 )。上述结果表明 :氦氖 (He -Ne)激光照射在抑制神经损伤后自残及促进周围神经再生等方面具有更显著的生理功效     

梨表面色泽的可见/近红外漫反射光谱无损检测研究

应用可见/近红外漫反射光谱对梨表面色泽进行无损检测研究.在350～1800nm光谱区间,结合梨的原始吸收光谱和标准化光谱,采用多元线性回归(MLR)、主成分回归(PCR)和偏最小二乘回归(PLSR)三种数学校正算法进行了定量对比分析.原始吸收光谱应用偏最小二乘回归建立的定标模型对24个未知样品的预测结果是:L*、a*、b*预测均方差分别为1.4251,0.4569和0.9497;相对预测偏差分别为3.7404%,3.3571%和2.5877%.实验结果表明:可见/近红外光谱技术对梨表面色泽的无损检测具有可行性.     

VEGF165基因修饰的神经干细胞对脑外伤大鼠的神经保护作用及机制

目的：探讨移植转染pDsVEGF165Redl-N1质粒的神经干细胞对脑外伤大鼠的神经保护作用及机制。方法：由新生大鼠脑组织分离培养神经干细胞,应用Lipofectamine2000介导pDsVEGF16sRed1-N1质粒转染神经干细胞;分别将PBS（A组）、神经干细胞（B组）、转基因神经干细胞（C组）移植到脑外伤大鼠局部损伤灶边缘;利用ELISA法检测转基因细胞在体内的表达情况,以免疫组化检测移植后局部损伤组织中微血管密度变化,通过NSS评分评价移植后大鼠神经功能的变化。结果：转基因细胞移植后在一定时间内持续表达VEGFl65,C组大鼠NSS评分从移植后第3天开始明显低于A组（P〈0．05）,而B组大鼠NSS评分则从移植后第7天开始明显低于A组（P〈0．05）,C组大鼠微血管密度从移植后第7天开始明显高于其他两组（P〈0．01）。结论：转基因神经干细胞表达的VEGF165既可以通过促进微血管再生和改善微循环发挥保护作用又可以直接作用于神经细胞发挥保护作用。     

FT-NIR光谱法定量分析烟草薄片中5种化学成分

为了研究近红外光谱分析技术预测烟草薄片中的总糖、总氮、烟碱、钾和氯含量的可行性,本文以250个具有代表性的烟草薄片样品的近红外漫反射光谱数据和它们相对应化学测定数据为基础,通过偏最小二乘回归法(PLS)建立了以上5种成分的近红外分析模型,并对模型的预测效果进行了评价.结果表明:近红外预测值与化学测定值之间具有很好的相关性,各模型均具有较好地预测准确性.总糖实际预测的平均相对误差为2.89%,总氮、烟碱、钾和氯模型实际预测的平均误差分别为0.10%,0.07%,0.19%和0.09%.各模型的预测重现性,即相对标准偏差(RSD)均小于4%.因此,可以用近红外光谱法快速、简便和大批量地分析烟草薄片中的以上5种化学成分.     

瘢痕疙瘩术后放射治疗疗效观察

目的:探讨瘢痕瘤切除术后给予不同放射治疗剂量的疗效。方法:回顾性分析1996年至2003年间95例瘢痕瘤切除术后在我科进行放射治疗患者的疗效,按放射治疗剂量分为A组:≤9GY/3次,一周内完成;B组:9-15GY,3~10天内分3~7次;C组:15-20GY/5-10次,1~2周内分5~10次。均于术后24小时开始放疗。结果:A、B、C组局部控制率分别为47.6%、84.5%、93.3%,其中A组与B、C组比较有统计学意义,P值分别为0.03、0.02,而B与C组比较无统计学意义,P=0.18。结论:瘢痕瘤术后放射治疗的总剂量以10-20GY为宜。     

烟梗原料4种常规化学组分的近红外快速分析

为了研究近红外光谱技术预测再造烟叶原料烟梗中烟碱(Nic)、总糖(Ts)、还原糖(Rs)及氯(Cl)含量的可行性,以上海薄片S、广东薄片烟梗原料及混梗原料等130个样品的近红外光谱结合偏最小二乘法建立以上4种常规化学组分的近红外漫反射模型,并对模型的预测效果、稳定性及准确性进行评估。结果表明:1烟碱、总糖、还原糖及氯模型的校正均方差(RMSEC)与预测均方差(RMSEP)接近且均较小,模型预测的相关系数(Corr.Coeff.)均在0.97以上。烟碱、总糖、还原糖及氯预测平均相对方差分别为3.47%、1.23%、1.31%和2.34%。2模型通过检验,发现模型的RMSEP/RMSEC接近1且其RPD值均大于3,表明近红外定量分析结果准确、可靠与流动分析法无显著性差异。     

白砂糖色值近红外光谱分析的波段选择

采用近红外漫反射光谱技术和偏最小二乘法(PLS)建立白砂糖色值的定量分析模型.用多元散射校正方法对光谱进行预处理,再用Savitzky-Golay平滑化方法对原谱、一阶导数谱和二阶导数谱进行处理.选取5个波段,每个波段分别采用原光谱、一阶导数谱、二阶导数谱.同时调整Savitzky-Golay平滑点数和PLS因子数,通过多次PLS数值实验比较,按照预测效果确定每个模型的最优平滑点数、因子数,再从中选优.结果表明,采用780～1100nm-阶导数谱的定标效果最好,模型的预测均方根偏差、相对预测均方根偏差分别为11.2,8.91%.780～1100nm可以代替近红外全谱波段(780～2500nm)得到好的定量分析效果,为设计小型专用近红外分析仪器提供依据.     

煤质的近红外光谱定量分析研究

实验中首先采用多元散射校正(MSC)的方法对煤粉样品的漫反射光谱进行了预处理,然后分别通过偏最小二乘法(PLS)和主成分分析(PCR)的方法建立煤粉样品的近红外光谱的全水分、挥发分和灰分的定量分析模型,通过预测集对建立的模型进行验证,发现利用偏最小二乘法建立的煤粉全水分模型最优,r=0.975,RMSEC=0.166,RMSEP=0.169,RPD=3.22,通过主成分分析方法建立的挥发分和灰分的模型最优,最后通过选取验证集样本对建立的模型进行了验证,得出利用近红外光谱分析技术间接对煤质进行定量分析是可行的。     

支架连接代替血管吻合建立大鼠肾移植模型

目的探讨抗淋巴细胞血清(ALS)联合他克莫司(FK506)在诱导大鼠肾脏移植免疫耐受中的作用。方法以SD大鼠作为供体,Wistar大鼠作为受体,建立大鼠肾移植模型。对照组(A组)仅行肾移植,术前术后未予免疫干预;ALS组(B组)术后当天腹腔注射ALS,连续应用至术后第10天;FK506组(C组)术后当天开始应用FK506,连续应用至术后第10天;联合组(D组)联合应用ALS与FK506。术后观测各组受者存活时间、移植肾功能、移植肾血供、免疫耐受状态等。结果D组平均存活时间为(37.0±5.3)d,与A组(7.4±1.6)d、B组(16.3±4.7)d及C组(17.5±5.3)d比较,差异均有统计学意义(P<0.05);手术后1周检查A组移植肾血供差,平均肾血管阻力指数0.80±0.06;B组和C组移植肾血供良好,平均阻力指数分别为0.62±0.07、0.63±0.08;D组移植肾血供良好,术后1周与术后20d平均阻力指数分别为0.61±0.04、0.62±0.03;D组与A组相比较差异有统计学意义(P<0.05)。结论ALS联合FK506能够延长受者存活时间和促进免疫耐受的诱导。     

用近红外光谱法快速无损检测苦豆子和决明子单粒种子生活力的研究

用傅里叶变换近红外漫反射光谱法测定了自然状态下单粒苦豆子与决明子种子的光谱,并结合定性偏最小二乘法对这两种种子的生活力进行了鉴别研究.研究结果表明,正反面两次平均光谱的建模效果要优于单次光谱;采用不同样品建模时,苦豆子与决明子模型的鉴别率均在90%以上.该研究为利用近红外光谱技术快速无损鉴定种子生活力提供了新的途径.     

Pulsed Doppler signal processing for use in mice: applications

We have developed a high-frequency, high-resolution Doppler spectrum analyzer (DSPW) and compared its performance against an adapted clinical Medasonics spectrum analyzer (MSA) and a zero-crossing interval histogram (ZCIH) used previously by us to evaluate cardiovascular physiology in mice. The aortic velocity (means /spl plusmn/ SE: 92.7 /spl plusmn/ 2.5 versus 82.2 /spl plusmn/ 1.8 cm/s) and aortic acceleration (8194 /spl plusmn/ 319 versus 5178 /spl plusmn/ 191 cm/s/sup 2/) determined by the DSPW were significantly higher compared to those by the MSA. Aortic ejection time was shorter (48.3/spl plusmn/ 0.9 versus 64.6 /spl plusmn/ 1.8 ms) and the isovolumic relaxation was longer (17.6 /spl plusmn/ 0.6 versus 13.5 /spl plusmn/0.6 ms) when determined by the DSPW because it generates shorter temporal widths in the velocity spectra when compared to the MSA. These data indicate that the performance of the DSPW in evaluating cardiovascular physiology was better than that of the MSA. There were no significant differences between the aortic pulse wave velocity determined by using the ZCIH (391 /spl plusmn/ 16 cm/s) and the DSPW (394 /spl plusmn/ 20 cm/s). Besides monitoring cardiac function, we have used the DSPW for studying peripheral vascular physiology in normal, transgenic, and surgical models of mice. Several applications such as the detection of high stenotic jet velocities (>4 m/s), vortex shedding frequencies (250 Hz), and subtle changes in wave shapes in peripheral vessels which could not obtained with clinical Doppler systems are now made possible with the DSPW.     

A Near‐Infrared cis‐Configured Squaraine Co‐Sensitizer for High‐Efficiency Dye‐Sensitized Solar Cells

A cis‐configured squaraine dye (HSQ1), synthesized by incorporation of a strongly electron‐withdrawing dicyanovinyl group into the central squaric acid moiety, is employed in dye‐sensitized solar cells (DSCs). In solution, HSQ1 displays an intense absorption in the near‐infrared region with a maximum at 686 nm and when the dye is adsorbed on a TiO₂ surface, the absorption spectrum broadens in both the blue and the near‐infrared regions, which is favorable for efficient light harvesting over a broad wavelength range. A solar cell sensitized with HSQ1 shows a broader incident photon‐to‐current conversion efficiency (IPCE) spectrum (from 400 to 800 nm) and a higher IPCE in the long‐wavelength region (71% at 700 nm) than a cell sensitized with squaraine dye SQ1. Furthermore, a solar cell co‐sensitized with HSQ1 and N3 dye shows remarkably improved short‐circuit current density and open‐circuit voltage compared to those of a DSC based on N3 alone and fabricated under the same conditions. The energy‐conversion efficiency of the co‐sensitized DSC is 8.14%, which is the highest reported efficiency for a squaraine dye–based co‐sensitized DSC without using Al₂O₃ layer.     

Monte Carlo modeling of light propagation in highly scattering tissues. I. Model predictions and comparison with diffusion theory

Using optical interaction coefficients typical of mammalian soft tissues in the red and near infrared regions of the spectrum, calculations of fluence-depth distributions, effective penetration depths and diffuse reflectance from two models of radiative transfer, diffusion theory, and Monte Carlo simulation are compared for a semi-infinite medium. The predictions from diffusion theory are shown to be increasingly inaccurate as the albedo tends to zero and/or the average cosine of scatter tends to unity.     

Impact of variable atmospheric water vapor content on AVHRR datacorrections over land

This paper explores the impact of the integrated water vapor content (IWV) in the atmospheric column on the corrections of optical satellite data over land. First, simulation runs were used to quantify the trends in red and near infrared parts of the electromagnetic spectrum. Second, advanced very high resolution radiometer (AVHRR) measurements obtained over Canada during the 1996 growing season, together with reanalyzed IWV content data, were employed to determine the actual impact of constant IWV values. Third, various options in characterizing IWV for atmospheric corrections of AVHRR composites were examined. It was found that (1) as expected, IWV affects near-infrared radiation substantially more than red, although the latter is also altered; (2) that additional, subtle interactions take place between IWV, radiance levels, and viewing geometry that influence the retrieved surface reflectance; (3) that spatial and temporal variation in IWV caused changes in the normalized difference vegetation index up to 7.5% in relative terms during the peak green period; and (4) that IWV varies so substantially that pixel and date-specific values need to be used for the atmospheric correction of AVHRR data. At present, subdaily gridded IWV data sets from atmospheric data reanalysis projects are the only candidate source for such purpose     

一种基于光子晶体的中远红外双波段兼容伪装材料

光子晶体作为一种新型人工结构功能材料,基于其光子禁带的高反射特性可以实现热红外伪装。选择红外波段透明的薄膜材料A、B,设计出在中远红外波段具有高反射禁带的光子晶体,利用薄膜光学理论的特征矩阵法计算了反射光谱。通过构造异质结构光子晶体,实现了光子带隙的展宽,该结构光子晶体基本上实现了中远红外双波段的高反射,在2.94~5.06μm和7.66~11.98μm波段的光谱反射率接近为1;在2.91~5.12μm和7.62~12.29μm波段的光谱反射率大于95%,较好地满足了中远红外双波段兼容伪装的要求。倾斜入射时光子晶体的TM波和TE波的反射光谱是不同的,随着入射角度的增加,TM波的带隙逐渐变窄,而TE波的带隙逐渐变宽。     

Highly Bright and Compact Alloyed Quantum Rods with Near Infrared Emitting: a Potential Multifunctional Nanoplatform for Multimodal Imaging In Vivo

Controlling synthesis of near‐infrared emitting quantum rods (QRs) for in vivo imaging is a major challenge in the fabrication of multifunctional nanoprobes. Here, a reliable synthetic approach for CdTe _x Se_1–x /ZnS alloy nanocrystals to achieve highly bright (quantum yields up to 80%) with controllable rod‐shape and near‐infrared (650–870 nm) emission is developed. Aspect ratio and emission of QRs are correlated with composition, which can be easily tuned by changing Te and Se mole ratio. It illustrates that the content of Se plays an important role in maintaining the rod‐shape, while Te has a significant impact on emitting of the nanorods. Besides exhibiting great stability over a broad range of pH (4–10) and ion strength (up to 2 mol L^‐1 NaCl solution), these hydrophilic QRs display good photo stability and storage stability. In particular, the specially absorbing of paramagnetic gadolinium ions on the QRs lead to a versatile method to engineer multimodal imaging nanoprobes, which are applied for in vivo lymph node dual‐modal imaging (fluorescence and magnetic resonance imaging). These results suggest a promising strategy for engineering multifunctional imaging nanoprobes with the stable near‐infrared QRs.     

基于扩散策略的实时分布式协作频谱检测算法

针对传统分布式协作频谱检测算法认知用户不能实时检测问题,该文提出基于扩散策略的实时分布式协作检测算法。算法利用各个节点的本地代价表示全局代价,通过最小化各个节点的代价使得全局代价最小。采用最速下降法,利用迭代方式计算各个节点检测量的最优估计值,得出估计值的理论稳态均值和方差,得出虚警概率、检测概率以及检测门限的封闭表达式。理论分析和实验结果表明,该算法能够有效解决分布式网络认知节点的实时检测问题,并具备快速学习和适应环境变化的能力。当虚警概率为0.01且检测概率达到0.9时,平均信噪比较平均共识和非实时扩散策略降低了约6 dB,能够实现在极低信噪比条件下的信号检测。     

传统艾灸与替代物灸和人体穴位红外辐射光谱比较

对传统艾灸、替代物灸和人体穴位红外辐射光谱的分析比较发现，隔附子饼灸、隔姜灸和隔蒜灸三种传统间接灸与人体穴位归一化红外辐射光谱有惊人的一致性，其辐射峰均在7。5μm附近；而几种替代物灸与相应传统艾灸和人体穴位的辐射光谱相差甚远，其温热作用也远不如传统艾灸；传统艾条黄灸与人体穴位红外辐射光谱也有很大差异。结果提示，在传统间接灸的治疗效应中，间接灸和穴位的红外共振辐射起重要作用；从艾灸的红外物理特性看，替代物灸尚不能替代传统艾灸。     

用于脑血流量检测的近红外光谱术

介绍了用于大脑血流量检测的近红外光谱术的基本原理和实验体系,该系统可完成对近红外光学信号的实时采集、处理和显示等功能。在血模型实验结果基础上,报道了大脑血流量变化的近红外光学检测结果。