No description available.

Thesis (M.S.)--University of Nevada, Reno, 2006. / "May, 2006." Includes bibliographical references (leaves 44-48). Online version available on the World Wide Web.

Graduation date: 1995

進入後基因時代，蛋白質體學成為很多科學家有興趣的主題。蛋白質鑑定成為重要的一環，而質譜儀在縮氨酸分析及蛋白質鑑定中扮演重要的角色。腫瘤、卵巢癌及攝護腺癌等研究亦已成為質譜儀上的應用。Coombes 等人 (2004) 提出了一個線性的數學質譜儀模型，而且建議這個模型可被應用在建立質譜儀的模擬中。本文中，我們利用虛擬的質譜儀產生虛擬質譜資料並加以研究。虛擬的質譜實驗包括了前、後兩部份。樣本資料要放入虛擬質譜儀之前，可能出現的蛋白質其強度(intensity)必須先隨機地被決定，之後強度必須被轉換(calibration)變成離子化的個數(abundance) ；之後將樣本資料丟入虛擬質譜儀中，每一個蛋白值的飛行時間(time of flight， TOF) 將會被紀錄。另外一個轉換(calibration)是將飛行時間(TOF)轉成質量電荷比(mass-to-charge ratio，m/z)。質譜儀和兩個轉換都會在資料中產生誤差。在本文中，一個完整的模擬過程將會一步一步被介紹。同時，兩個轉換的方法所產生的誤差也會被探討。之後，我們將此模擬方法應用於模擬一組攝護腺癌中。 / Entering the post genomic era, proteomic has become the topic that scientists are interested in. The authentication of protein has been an important item of the topics. Mass spectrometry (MS) has become an important tool for peptide analysis or proteomic authentication. There are many applications of MS such as oncology, ovarian cancer, and prostate cancer. Coombes et al.(2004) proposed a mathematical model of a virtual spectrometer and suggested that the virtual spectrometer can be applied in conducting a MS simulation. In our study, we focus on designing a simulation study of spectrum data from a virtual MS experiment. The virtual experiment includes two stages: pre- and post-virtual spectrometer. Before the sample data are put into the virtual spectrometer, a virtual population of the intensity of all possible proteins should be determined; a virtual sample is randomly drawn; and the generated sample of intensity should be calibrated to abundance, which is the number of molecules ionized and desorbed from the biological sample. The sample data are then put into the virtual spectrometer and the time of flight (TOF) of each ionized molecule is recorded. Another calibration is employed to transfer a TOF to a mass-to-charge ratio (m/z). The spectrometer and the calibration processes produce variation in MS data. In this study, a complete simulation design of mass spectra will be introduced step by step. Moreover, the calibration effects caused from the two calibration procedures will be investigated. A simulation based on a real data set from a prostate cancer study will be also given as an illustration.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: infrared spectroscopy; aerosols; nucleation; tunable diode laser; condensation; supersonic nozzles. Includes bibliographical references (p. 73-76).

No description available.

An accurate response function for a superconducting solenoid beta spectrometer for electrons up to 5.5 MeV has been found using Monte Carlo calculations and measurements of standard spectra. Experimental conditions affecting the response function have been studied and corrections for source scattering and pileup devised. / An anomalous shift in the electron energy calibration caused by the magnetic field has been discovered and explained. / The beta spectrum of ('32)P, ('90)Y, ('28)Al, ('42)K, ('38)Cl and ('88)Rb have been studied. Systematic uncertainties in endpoint, branch intensity and shape factor measurements have been estimated. / A beta spectra analysis program has been written to calculate endpoints, branch intensities and shape factors in a multi-branch spectrum. / The beta spectra of ('141)La, ('142)La, ('139)Ba, ('141)Ba, ('142)Ba, ('138)Cs and ('139)Cs have been studied. Q(,(beta))-values, intensities for all branches and some shape factors have been measured. / The shape factor of the ('20)F beta spectrum has been measured. The value found for the linear coefficient, a = 0.006 (+OR-) .002 (mc('2))('-1), supports the "weak magnetism" predictions of the Conserved Vector Current theory.

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

The design, implementation and commissioning of a time-resolved electron energy spectrometer system are discussed. Since its installation at the FELIX free-electron laser user facility in Nieuwegein, The Netherlands, the spectrometer system has been in regular use as a diagnostic and investigative tool. The system provides 0.2% energy resolution with 32 channels, and time resolution of 50 ns. The spectrometer is positioned immediately following the undulator so that the gain medium—the relativistic electron beam—can be probed immediately following its interaction with the optical field in the laser cavity. The system permits real-time calculation and graphical display of key beam parameters as well as the archiving of raw data, and has been used to provide insight into the operation of an FEL in the high slippage, short pulse regime. In particular, direct measurement of the extraction efficiency is possible from macropulse to macropulse. A systematic study of efficiency as a function of wavelength and cavity desynchronisation has been undertaken. At low values of cavity desynchronisation the efficiencies measured exceed the conventional 1/2/V estimate by between 50% and 100% and these results are shown to be consistent with the formation of ultrashort optical pulses—approximately of 6 optical cycles in length. An investigation into the way in which the electron beam energy can be swept on a microsecond time scale has made it possible to produce given sweeps in wavelength—of up to 2 %, limited only by the constraints of the electron beam transport system—which have been used by molecular spectroscopists to excite target molecules through an anharmonic ladder of states. Further evidence for the recent observation of superradiance in an FEL oscillator has been provided by an investigation which shows that the efficiency and intracavity power of the radiation scale respectively as the inverse square root and the inverse square of the cavity losses, verifying the superradiant scaling laws predicted by the supermode theory. An important consequence of this observation is that it indicates that shorter and more intense optical pulses may be produced by increasing the bunch charge and reducing optical cavity losses.

Early detection of disease and insect infestation within crops and precise application of pesticides can help reduce potential production losses, reduce environmental risk, and reduce the cost of farming. The goal of this study was the advanced detection of early blight (Alternaria solani) in potato (Solanum tuberosum) plants using hyperspectral remote sensing data captured with a handheld spectroradiometer. Hyperspectral reflectance spectra were captured 10 times over five weeks from plants grown to the vegetative and tuber bulking growth stages. The spectra were analyzed using principal component analysis (PCA), spectral change (ratio) analysis, partial least squares (PLS), cluster analysis, and vegetative indices. PCA successfully distinguished more heavily diseased plants from healthy and minimally diseased plants using two principal components. Spectral change (ratio) analysis provided wavelengths (490-510, 640, 665-670, 690, 740-750, and 935 nm) most sensitive to early blight infection followed by ANOVA results indicating a highly significant difference (p < 0.0001) between disease rating group means. In the majority of the experiments, comparisons of diseased plants with healthy plants using Fisher’s LSD revealed more heavily diseased plants were significantly different from healthy plants. PLS analysis demonstrated the feasibility of detecting early blight infected plants, finding four optimal factors for raw spectra with the predictor variation explained ranging from 93.4% to 94.6% and the response variation explained ranging from 42.7% to 64.7%. Cluster analysis successfully distinguished healthy plants from all diseased plants except for the most mildly diseased plants, showing clustering analysis was an effective method for detection of early blight. Analysis of the reflectance spectra using the simple ratio (SR) and the normalized difference vegetative index (NDVI) was effective at differentiating all diseased plants from healthy plants, except for the most mildly diseased plants. Of the analysis methods attempted, cluster analysis and vegetative indices were the most promising. The results show the potential of hyperspectral remote sensing for the detection of early blight in potato plants.