750 research outputs found

    Laser Ablation of Polymethylmethacrylate (PMMA) by Phase- Controlled Femtosecond Two-Color Synthesized Waveforms

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    Single-shot laser ablation of polymethylmethacrylate (PMMA) was studied using dual-color waveform synthesis of the fundamental (ω) and its second harmonic (2ω) of a femtosecond Ti: Sapphire laser. Changing the relative phase of the fundamental (ω) and second-harmonic (2ω) outputs of the exciting laser resulted in clear modulation of the ablated area. The modulation as well as the dependence of the ablation threshold on the relative phase between the ω and 2ω beams correlated closely with the theoretical model of laser breakdown (ablation) of transparent materials through photoionization in the intermediate regime (Keldysh parameter γ ≈ 1.5). Our study illustrates the potential applications of using phase-controlled synthesized waveform for laser processing of materials

    Hemispheric dispersion of radioactive plume laced with fission nuclides from the Fukushima nuclear event

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    Radioactivities of particulate 131I and 137Cs released from the Fukushima nuclear accident were monitored in a regional aerosol network including two high mountain sites (central Taiwan and Tibetan Plateau). The results were integrated with data measured elsewhere around the world, with special focus on the mid-latitudes. The hemispheric transport of the Fukushima radiation clouds (FRCs) by the westerlies took 18days,displayinganexponentiallikedecreaseeastward,withadilutionfactorofatleastfiveordersofmagnitudefollowingafullcircuitaroundtheglobe.TheinitialtwowavesofFRCsmaytravelatdifferentatitudes:thefirstoneat18 days, displaying an exponential-like decrease eastward, with a dilution factor of at least five orders of magnitude following a full circuit around the globe. The initial two waves of FRCs may travel at different atitudes: the first one at 3–4 km, whereas the second one up to 5 km or more. 131I and 137Cs were fractionated during transport, with 137Cs concentrated in the shallower layer, susceptible to depositional removal, while 131I moving faster and higher. This accident may be exemplified to identify some atmospheric processes on the hemispheric scale

    White-Matter Structural Connectivity in Relation to Humor Styles: An Exploratory Study

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    To investigate the potential relationship between white matter (WM) microstructure and humor styles, diffusion tensor images of brain WM and humor style tendencies were obtained from thirty healthy adults. Using connectivity efficiency measures from graph theoretical analysis and controlling for the influence of gender, age, educational level, and the big five personality traits, we preliminarily examined the prediction of humor styles from brain network efficiency. The results showed that the local efficiency within particular brain networks positively predicted a self-enhancing humor style and negatively predicted an aggressive humor style. The node efficiency of the left superior temporal gyrus distinguished the benevolent or hostile way that individuals coped with interpersonal embarrassment. These findings from this exploratory study support the hypothesis that WM structure influences humor styles, and provide the initial evidence and implications regarding the relationship between biological mechanisms and mental health for future research

    Technology Anxiety and Implicit Learning Ability Affect Technology Leadership to Promote the use of Information Technology at Elementary Schools

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    Abstract“Oversold & underused” is a criticism by Cuban (2001) of the investment of information technology (IT) in the classroom. Recently, Taiwan's educational administration has provided considerable financial support to IT in elementary schools, but few reports have provided evidence of its successful use. The present study aims to identify the personal factors that affect principals’ beliefs about the promotion of IT in their schools. 331 data were collected and analyzed with AMOS 19.0. The results of this study indicated that greater technology anxiety was negatively associated with perceived ease of using (PEU) IT, whereas implicit learning ability was positively correlated with perceived usefulness of IT. Technology leadership increased significantly with PEU and perceived usefulness (PU), it is also associated with the intention to overcome difficulties in promoting information technology in schools. The implications of this study may contribute to the reduction of principals’ technology anxiety, increasing their implicit learning ability and therefore fostering the future implementation of IT in schools, changing the myth of technology as “oversold & underused”

    Hypertension is an important predictor of recurrent colorectal adenoma after screening colonoscopy with adenoma polypectomy

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    AbstractBackgroundThe predictors of recurrent colorectal adenoma have not been fully examined. This study aimed to evaluate the predictors of recurrent colorectal adenoma after initial screening colonoscopy with adenoma polypectomy.MethodsA retrospective cohort study was conducted at the Taipei Veterans General Hospital from 2003 to 2011. After screening, 356 patients who had undergone two consecutive colonoscopies with colorectal adenoma polypectomy at the initial colonoscopy were enrolled. The recurrence group was patients with recurrent colorectal adenoma at the second colonoscopy, whereas the nonrecurrence group was patients without recurrence. Anthropometric data, biochemical tests, metabolic comorbidities, and adenoma characteristics at initial colonoscopy were compared between the two groups. Cox proportional hazard regression analysis was conducted to identify the predictors of recurrent colorectal adenoma.ResultsDuring a mean follow-up interval of 3.07 ± 1.42 years, 94 patients (26.4%) were in the recurrence group, 262 patients (73.6%) were in the nonrecurrence group. The recurrence group was older, had a wider waist circumference, higher levels of serum alanine aminotransferase (ALT) and triglyceride, a higher prevalence of smoking, nonalcoholic fatty liver disease, metabolic syndrome, and hypertension, and a higher occurrence of initial multiply-located adenomas when compared with the nonrecurrence group (p < 0.05). Cox regression analysis showed that hypertension, smoking, higher ALT level (>40 IU/mL), and multiply-located adenomas were independent predictors for recurrent colorectal adenoma. The risk of recurrent adenoma increased when hypertension was combined with smoking, high ALT level, or multiply-located adenomas.ConclusionHypertension is an important predictor for recurrent colorectal adenoma after screening colonoscopy with polypectomy

    Trypsin-induced proteome alteration during cell subculture in mammalian cells

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    <p>Abstract</p> <p>Background</p> <p>It is essential to subculture the cells once cultured cells reach confluence. For this, trypsin is frequently applied to dissociate adhesive cells from the substratum. However, due to the proteolytic activity of trypsin, cell surface proteins are often cleaved, which leads to dysregulation of the cell functions.</p> <p>Methods</p> <p>In this study, a triplicate 2D-DIGE strategy has been performed to monitor trypsin-induced proteome alterations. The differentially expressed spots were identified by MALDI-TOF MS and validated by immunoblotting.</p> <p>Results</p> <p>36 proteins are found to be differentially expressed in cells treated with trypsin, and proteins that are known to regulate cell metabolism, growth regulation, mitochondrial electron transportation and cell adhesion are down-regulated and proteins that regulate cell apoptosis are up-regulated after trypsin treatment. Further study shows that bcl-2 is down-regulated, p53 and p21 are both up-regulated after trypsinization.</p> <p>Conclusions</p> <p>In summary, this is the first report that uses the proteomic approach to thoroughly study trypsin-induced cell physiological changes and provides researchers in carrying out their experimental design.</p

    YamSat: the First Picosatellite being Developed in Taiwan

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    This paper describes the current planning and design of the YamSat, the first picosatellite being developed in Taiwan. The design, analysis, manufacture, integration, test and operation of the YamSat will be performed by the National Space Program Office (NSPO), Taiwan, R.O.C, in cooperation with other domestic organizations and companies. It is a member of the CubeSat [1], 10cm x 10cm x 10cm size and within 1kg mass. The major objective of the YamSat is to qualify in space the components and technology developed in Taiwan, including a micro-spectrometer payload using Micro Electro Mechanical Systems (MEMS) technology. The YamSat will be ready for flight in the middle of 2002

    Complete chloroplast genome of Oncidium Gower Ramsey and evaluation of molecular markers for identification and breeding in Oncidiinae

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    <p>Abstract</p> <p>Background</p> <p><it>Oncidium </it>spp. produce commercially important orchid cut flowers. However, they are amenable to intergeneric and inter-specific crossing making phylogenetic identification very difficult. Molecular markers derived from the chloroplast genome can provide useful tools for phylogenetic resolution.</p> <p>Results</p> <p>The complete chloroplast genome of the economically important <it>Oncidium </it>variety <it>Onc</it>. Gower Ramsey (Accession no. GQ324949) was determined using a polymerase chain reaction (PCR) and Sanger based ABI sequencing. The length of the <it>Oncidium </it>chloroplast genome is 146,484 bp. Genome structure, gene order and orientation are similar to <it>Phalaenopsis</it>, but differ from typical Poaceae, other monocots for which there are several published chloroplast (cp) genome. The <it>Onc</it>. Gower Ramsey chloroplast-encoded <it>NADH dehydrogenase </it>(<it>ndh</it>) genes, except <it>ndhE</it>, lack apparent functions. Deletion and other types of mutations were also found in the <it>ndh </it>genes of 15 other economically important Oncidiinae varieties, except <it>ndhE </it>in some species. The positions of some species in the evolution and taxonomy of Oncidiinae are difficult to identify. To identify the relationships between the 15 Oncidiinae hybrids, eight regions of the <it>Onc</it>. Gower Ramsey chloroplast genome were amplified by PCR for phylogenetic analysis. A total of 7042 bp derived from the eight regions could identify the relationships at the species level, which were supported by high bootstrap values. One particular 1846 bp region, derived from two PCR products (<it>trnH</it><sup>GUG </sup>-<it>psbA </it>and <it>trnF</it><sup>GAA</sup>-<it>ndhJ</it>) was adequate for correct phylogenetic placement of 13 of the 15 varieties (with the exception of <it>Degarmoara </it>Flying High and <it>Odontoglossum </it>Violetta von Holm). Thus the chloroplast genome provides a useful molecular marker for species identifications.</p> <p>Conclusion</p> <p>In this report, we used <it>Phalaenopsis. aphrodite </it>as a prototype for primer design to complete the <it>Onc</it>. Gower Ramsey genome sequence. Gene annotation showed that most of the <it>ndh </it>genes inOncidiinae, with the exception of <it>ndhE</it>, are non-functional. This phenomenon was observed in all of the Oncidiinae species tested. The genes and chloroplast DNA regions that would be the most useful for phylogenetic analysis were determined to be the <it>trnH</it><sup>GUG</sup>-<it>psbA </it>and the <it>trnF</it><sup>GAA</sup>-<it>ndhJ </it>regions. We conclude that complete chloroplast genome information is useful for plant phylogenetic and evolutionary studies in <it>Oncidium </it>with applications for breeding and variety identification.</p

    The incidence and risk of developing a second primary esophageal cancer in patients with oral and pharyngeal carcinoma: a population-based study in Taiwan over a 25 year period

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    <p>Abstract</p> <p>Background</p> <p>The incidence of oral and pharyngeal (including oral cavity, oropharynx and hypopharynx) carcinoma increases rapidly in Asia and South Pacific because of betel quid chewing. Thus far, large-scale epidemiological studies are not available yet to stratify these patients by their risks of developing a second primary cancer in the digestive tract including esophagus, stomach, colon, and rectum.</p> <p>Methods</p> <p>A population-based study was conducted using the database from the Taiwan National Cancer Registry for the period 1979-2003. We quantified standardized incidence ratios (SIRs) and cumulative incidence of second primary cancers among 33,787 patients with initial diagnoses of oral and pharyngeal carcinoma.</p> <p>Results</p> <p>Among these four digestive tract organs, the esophagus was the only site of second cancer with excess risk in patients with oral and pharyngeal carcinoma. The incidence and risk of developing a second primary esophageal cancer differed by the site of the primary index tumor, most frequently seen in hypopharyngeal cancer (71/4,218 = 1.68%, SIR = 22.76, 95% CI 17.77-28.70), followed by oropharyngeal cancer (30/3,403 = 0.88%, SIR = 14.29, 95% CI 9.64-20.39) and the least in oral cavity cancer (99/26,166 = 0.38%, SIR = 5.57, 95% CI 4.53-6.78). In addition, the risk was extraordinarily high for patients with a follow-up interval ≤ 1 year and those with first primary cancer diagnosed at age ≤50. These patients may justify more close surveillance.</p> <p>Conclusion</p> <p>The present study represents the first population-based study in Asia attempting to stratify the patients of oral and pharyngeal carcinoma by their risk of developing a second esophageal cancer. It helps identify patients at high risk and tailor the application of intense follow-up surveillance to the estimated risk in each individual case.</p
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