576 research outputs found

    Design and Development of Novel Electroplating Spring Frame Mems Structure Specimens for the Microtensile Testing of Thin Film Materials

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    Microelectromechanical systems (MEMS) technologies are developing rapidly with increasing study of the design, fabrication and commercialization of microscale systems and devices. Accurate mechanical properties are important for successful design and development of MEMS. We have demonstrated here a novel electroplating spring frame MEMS Structure Specimen integrates pin-pin align holes, misalignment compensate spring structure frame, load sensor beam and freestanding thin film. The specimen can be fit into a specially designed microtensile apparatus which is capable of carrying out a series of tests on sub-micro scale freestanding thin films.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

    Perforated Appendiceal Mucinous Cystadenoma Mimicking Ruptured Appendicitis With Abscess Formation: CT Imaging Features

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    AbstractWe describe the imaging features of a perforated appendiceal mucinous cystadenoma in a 72-year-old woman presenting with right lower quadrant abdominal pain, mimicking ruptured appendicitis with abscess formation. Computed tomography revealed a rim-enhanced cystic lesion at the proximal appendiceal orifice, connecting with the swollen and dilated distal part of the appendix. Disruption of the appendiceal walls and peri-appendiceal fatty infiltrations were also noted. Under the impression of ruptured appendicitis with abscess formation, the patient underwent exploratory laparotomy and appendectomy. The pathologic diagnosis was perforated appendiceal mucinous cystadenoma associated with superinfection, complicated by secondary appendicitis. The patient was uneventfully discharged on the 7th hospital day. Although primary neoplasms of the appendix are uncommon, they should be considered as a predisposing factor in elderly patients manifesting with appendicitis

    Ringtone Regardless of P-Early-Media Tag

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    A user device placing a mobile originating call on a network using Real-time Transport Protocol (RTP) ignores P-Early-Media tags and session description protocol (SDP) in Session Initiation Protocol (SIP) packets received from the network after receiving a 180 Ringing alert packet indicating that the receiving device is ringing to minimize a delay in playing a ringback tone. The user device plays a local ringtone until the user device receives audio RTP packets containing Early Media. If the user device receives audio RTP packets containing Early Media before the call is connected, the user device plays the Early Media as a custom ringtone

    Antagonism between abscisic acid and ethylene in Arabidopsis acts in parallel with the reciprocal regulation of their metabolism and signaling pathways

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    Although abscisic acid (ABA) and ethylene have antagonistic functions in the control of plant growth and development, including seed germination and early seedling development, it remains unknown whether a convergent point exists between these two signaling pathways or whether they operate in parallel in Arabidopsis thaliana. To elucidate this issue, four ethylene mutants, ctr1, ein2, ein3, and ein6, were crossed with aba2 (also known as gin1-3) to generate double mutants. Genetic epistasis analysis revealed that all of the resulting double mutants displayed aba2 mutant phenotypes with a small plant size and wiltiness when grown in soil or on agar plates. Further ethylene sensitivity or triple response analyses demonstrated that these double mutants also retained the ctr1 or ein mutant phenotypes, showing ethylene constitutive triple and insensitive responses, respectively. Our current data therefore demonstrate that ABA and ethylene act in parallel, at least in primary signal transduction pathways. Moreover, by microarray analysis we found that an ACC oxidase (ACO) was significantly upregulated in the aba2 mutant, whereas the 9-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3) gene in ein2 was upregulated, and both the ABSCISIC ACID INSENSITIVE1 (ABI1) and cytochromeP450, family 707, subfamily A, polypeptide 2 (CYP707A2) genes in etr1-1 were downregulated. These data further suggest that ABA and ethylene may control the hormonal biosynthesis, catabolism, or signaling of each other to enhance their antagonistic effects upon seed germination and early seedling growth

    Crystallization of Adenylylsulfate Reductase from Desulfovibrio gigas: A Strategy Based on Controlled Protein Oligomerization

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    Adenylylsulfate reductase (adenosine 5′-phosphosulfate reductase, APS reductase or APSR, E.C.1.8.99.2) catalyzes the conversion of APS to sulfite in dissimilatory sulfate reduction. APSR was isolated and purified directly from massive anaerobically grown Desulfovibrio gigas, a strict anaerobe, for structure and function investigation. Oligomerization of APSR to form dimers–α_2β_2, tetramers–α_4β_4, hexamers–α_6β_6, and larger oligomers was observed during purification of the protein. Dynamic light scattering and ultracentrifugation revealed that the addition of adenosine monophosphate (AMP) or adenosine 5′-phosphosulfate (APS) disrupts the oligomerization, indicating that AMP or APS binding to the APSR dissociates the inactive hexamers into functional dimers. Treatment of APSR with β-mercaptoethanol decreased the enzyme size from a hexamer to a dimer, probably by disrupting the disulfide Cys156—Cys162 toward the C-terminus of the β-subunit. Alignment of the APSR sequences from D. gigas and A. fulgidus revealed the largest differences in this region of the β-subunit, with the D. gigas APSR containing 16 additional amino acids with the Cys156—Cys162 disulfide. Studies in a pH gradient showed that the diameter of the APSR decreased progressively with acidic pH. To crystallize the APSR for structure determination, we optimized conditions to generate a homogeneous and stable form of APSR by combining dynamic light scattering, ultracentrifugation, and electron paramagnetic resonance methods to analyze the various oligomeric states of the enzyme in varied environments

    Aging-Induced Dynamics for Statically Indeterminate System

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    Statically indeterminate systems are experimentally demonstrated to be in fact dynamical at the microscopic scale. Take the classic ladder-wall problem, for instance. Depending on the Young's modulus of the wall, it may take up to twenty minutes before its weight saturates. This finding is shown to be shared by other statically indeterminate systems, such as a granule silo and a beam with three support points. We believe that the aging effect is responsible for this surprising phenomenon because it can be correlated with the evolution of microscopic contact area with the wall and floor. Finally, a heuristic and simple method is introduced that can uniquely determine and analytically solve the saturated weight without invoking detailed material properties.Comment: 5 pages, 5 figure

    New primers for methylation-specific polymerase chain reaction enhance specificity of detecting STAT1 methylation

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    AbstractObjectiveSignal transducer and activator of transcription (STAT)1 is a key tumor suppressor, which is always methylated in a variety of human cancers. However, nonspecific primers for the detection of specific promoter hypermethylation of STAT1 gene can lead to false-positive or false-negative results for gene methylation.Materials and MethodsWe designed new primers for the detection of STAT1 methylation and compared the sensitivities and specificities of these new primers with prior published primers by methylation-specific polymerase chain reaction (PCR) from ovarian clear cell carcinomas. The mRNA expression levels of STAT1 in these cancerous tissues were also evaluated by reverse-transcriptase PCR and correlated with the results of promoter methylation of STAT1 gene.ResultsNine (39%) of the 23 samples detected by the new primers and 13 samples (56%) detected by prior published primers showed STAT1 methylation. A direct DNA sequencing test revealed that four of the 13 samples (30.8%) showed false positivity for STAT1 methylation using the prior published primers. In contrast, none of the nine samples was false-positive for the detection of STAT1 methylation using the new primers. The new primers for the detection of STAT1 methylation showed 100% specificity and 100% sensitivity without false positivity.ConclusionSpecific primers for methylation-specific PCR are mandatory for the accurate detection of STAT1 gene methylation. Besides, specific primers can generate correct interpretation of STAT1 gene methylation, and its correlation with the clinicopathological characteristics and outcome of cancer patients

    HPV infection and p53 inactivation in pterygium

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    PurposeOur recent report indicated that tumor suppressor gene (p53) mutations and protein aberrant expression were detected in pterygium. Inactivation of p53 by Human papillomavirus (HPV) 16/18 E6 plays a crucial role in cervical tumorigenesis. In this study, we further speculate that p53 inactivation may be linked with HPV infection in pterygium pathogenesis. To investigate the involvement of HPV 16/18 E6 in p53 inactivation in pterygium, the association between HPV 16 or HPV 18 infection, the HPV E6 oncoprotein, and p53 protein expression was analyzed in this study.MethodsHPV 16/18 infection was detected by nested-polymerase chain reaction (nested-PCR), the p53 mutation was detected by direct sequencing, and the p53 and the HPV 16/18 E6 proteins were studied using immunohistochemistry on 129 pterygial specimens and 20 normal conjunctivas.ResultsThe HPV 16/18 was detected in 24% of the pterygium tissues (31 of 129) but not in the normal conjunctiva, and the HPV16/18 E6 oncoprotein was detected in 48.3% of HPV 16/18 DNA-positive pterygium tissues (15 of 31). In addition, p53 protein negative expression in pterygium was correlated with HPV16/18 E6 oncoprotein expression but not with a p53 mutation.ConclusionsHPV 16/18 E6 contributes to HPV-mediated pterygium pathogenesis as it is partly involved in p53 inactivation and is expressed in HPV DNA-positive pterygium
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