Poor detection limits and strong salt effects are two of the main problems encountered in the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometric analysis of DNA. This work demonstrates that a probe tip with a paraffin wax film (Parafilm) surface improves the MALDI performance in DNA analysis compared to the commonly used metal surface. First, the use of Parafilm increases the detection sensitivity. It was found that the detection limit achieved with Parafilm was 5 times better than that obtained using stainless steel for a 85mer. More importantly, the Parafilm method could improve detection of larger DNA components in the presence of a large excess of a smaller DNA component or in a DNA mixture. This feature is important to analyses of PCR and sequencing products. Second, we found that the use of Parafilm increased the salt tolerance limits for the 17-, 41-, and 85mers studied in this work and that the salt effect was less sensitive to the DNA size. Third, this method offers other analytical benefits, including producing a more homogeneous coverage of matrix/DNA, adding no extra cost and time to sample preparation, and eliminating the commonly required step for cleaning the probe after analysis. In this paper, we will also present our perspectives on why the use of Parafilm can improve the MALDI-TOF performance in DNA analysis.

Matrix-assisted laser desorption/ionization mass spectrometry of DNA and proteins, directly deposited on the poly(tetrafluoroethylene) (Teflon) surface, is demonstrated. For DNA analysis, this technique apparently produces a more homogeneous coverage of the matrix/DNA over the sample surface. Moreover, it enhances the sensitivity and salt tolerance. As described here, this technique can also achieve an excellent mass resolution, similar to that observed using a metal probe for DNA up to 62mer. We also examined the use of Teflon as a sample support for protein analysis since Teflon has been used as a transfer membrane. Less than 25 fmol of myoglobin has been detected with this technique. In addition, effective MALDI-TOF analysis of salt-contaminated protein samples can also be accomplished by loading the protein sample onto Teflon, followed by steps of washing away salts, adding the matrix, and desorbing sample directly from Teflon.

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The world's ageing population and prevalence of chronic diseases have lead to high demand for tele-home healthcare, in which vital-signs monitoring is essential. An overview of state-of-art wearable technologies for remote patient-monitoring is presented, followed by case studies on a cuffless blood pressure meter, ring-type heart rate monitor, and Bluetoothtrade mark-based ECG monitor. Aim of our project is to develop a tele-home healthcare system which utilizes wearable devices, wireless communication technologies, and multisensor data fusion methods. As an important part of this system, a cuffless BP meter has been developed and tested on 30 subjects in a total of 71 trials over a period of five months. Preliminary results show a mean error (ME) of 1.82 mmHg and standard deviation of error (SDE) of 7.62 mmHg in systolic pressure; while ME and SDE in diastolic pressure are 0.45 mmHg and 5.27 mmHg, respectively.

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A new MALDI-TOF based mini-sequencing assay termed VSET was developed for genotyping of SNPs. In this assay, specific fragments of genomic DNA containing the SNP site(s) are first amplified, followed by mini-sequencing in the presence of three ddNTPs and the fourth nucleotide in the deoxy form. In this way, the primer is extended by only one base from one allele, while it is typically extended by two bases from another allele. The products are then analyzed using MALDI-TOF mass spectrometry. The genotype of the SNP site is identified based on the number of nucleotides added. This assay has been examined using both synthetic and genomic DNA samples. In addition, multiplexed assays were successfully performed to genotype four SNP sites in a single tube. The main aspect of this assay is that it can overcome the key problems associated with the currently used mini-sequencing methods. First, it significantly reduces the stringent high-resolution and extensive desalting requirements that are essential to the pinpoint assay. Second, it avoids the long extension problem associated with the PROBE assay.

Iron is essential for pathogen survival, virulence, and colonization. Feo is suggested to function as the ferrous iron (Fe 2؉ ) transporter. The enterobacterial Feo system is composed of 3 proteins: FeoB is the indispensable component and is a large membrane protein likely to function as a permease; FeoA is a small Src homology 3 (SH3) domain protein that interacts with FeoB; FeoC is a winged-helix protein containing 4 conserved Cys residues in a sequence suitable for harboring a putative iron-sulfur (Fe-S) cluster. The presence of an iron-sulfur cluster on FeoC has never been shown experimentally. We report that under anaerobic conditions, the recombinant Klebsiella pneumoniae FeoC (KpFeoC) exhibited hyperfine-shifted nuclear magnetic resonance (NMR) and a UV-visible (UV-Vis) absorbance spectrum characteristic of a paramagnetic center. The electron paramagnetic resonance (EPR) and extended X-ray absorption fine structure (EXAFS) results were consistent only with the [4Fe-4S] clusters. Substituting the cysteinyl sulfur with oxygen resulted in significantly reduced cluster stability, establishing the roles of these cysteines as the ligands for the Fe-S cluster. When exposed to oxygen, the [4Fe-4S] cluster degraded to [3Fe-4S] and eventually disappeared. We propose that KpFeoC may regulate the function of the Feo transporter through the oxygen-or iron-sensitive coordination of the Fe-S cluster.

An increased Cav-1 expression is seen in the stepwise carcinogenesis from NOM, NCMT, OPL to POSCC. The decrease in expression from the POSCC to MOSCC indicates the value to explore its biphasic functions in oral carcinogenesis. Whether Cav-1 is an important predictor or prognosis for survival still awaits the extension of clinical follow-up.