79 research outputs found
Temperature effects on the bulk discharge current of dielectric films of MEMS capacitive switches
Kelvin probe method has been directly applied to capacitive MEMS switches in order to investigate temperature activated mechanisms in PECVD Silicon Nitride (SiNx) films. The bulk discharge current of MEMS capacitive switches has been determined for different charging and discharging temperatures, in the range of 300–400 K. The increase of discharging temperature leads to an increase of the magnitude of the bulk discharge current and the relaxation time of the discharging process is found to be thermally activated. Finally, it is shown that the increase of charging temperature assists trapping at centers characterized by time constants even longer than the time window of observation, i.e. 10^4 s
Charging and Discharging Processes in AlN Dielectric Films Deposited by Plasma Assisted Molecular Beam Epitaxy
In the present work the electrical properties of AlN polycrystalline films deposited at low temperatures by plasma-assisted molecular beam epitaxy (PA-MBE) are investigated. The polarization build-up during constant current injection as well as the depolarization process after the current stress have been investigated through monitoring voltage transients in Metal – Insulator – Metal (MIM) capacitors, in temperature range from 300 K to 400 K. Moreover, current – voltage characteristics obtained at different temperatures revealed that charge collection at low fields in these films occurs through variable range hopping
Properties of contactless and contacted charging in MEMS capacitive switches
The dielectric charging in MEMS capacitive switches is a complex effect. The high electric field during pull-down causes intrinsic free charge migration and dipole orientation as well as charge injection. The macroscopic dipole moment of the first two mechanisms is opposite to the one arising from charge injection. This causes partial compensation hence mitigates the overall charging and increases the device lifetime. The charging due to intrinsic free charge migration and dipole orientation can be monitored under contactless electric field application in the pull-up state. The paper investigates the characteristics of contactless charging and compares them with the ones of contacted charging. The characteristics of the discharging process that follows each charging procedure are also presented
Near-field microwave techniques for micro – and nano - scale characterization in materials science
In this paper, the basic principles of Near-Field Microscopy will be reviewed with focus on the micro-
and nano-scale resolution configurations for material science measurements. Results on doping profile, dielectric
and magnetic properties will be presented, with details on the calibration protocols needed for quantitative estimation
of the dielectric constant and of the permeability
Successful myomectomy during pregnancy : A case report
BACKGROUND: The medical literature has reported an increase in myomectomy during caesarean section in the past decade. However, myomectomy performed during pregnancy remains a rarity. The management of uterine fibroids during pregnancy is usually expectant and surgical removal is generally delayed until after delivery. We present a case of a large, symptomatic uterine fibroid diagnosed during pregnancy which was successfully managed by antepartum myomectomy. CASE PRESENTATION: A 30 year old woman presented with a one year history of abdominal swelling, amenorrhea and severe epigastric discomfort of 19 weeks duration. The abdomen was grossly distended and tense. A sonographic diagnosis of ovarian tumor in pregnancy was made. Laparotomy revealed a 32 cm degenerating subserosal uterine fibroid co-existing with an intrauterine pregnancy. Myomectomy was successfully performed. The subsequent antenatal period was uneventful with a spontaneous vaginal delivery of a female baby at 38 weeks. CONCLUSION: This report supports other studies and case series that have demonstrated the safety of myomectomy during pregnancy in selected circumstances
Secure and scalable deduplication of horizontally partitioned health data for privacy-preserving distributed statistical computation
Background
Techniques have been developed to compute statistics on distributed datasets without revealing private information except the statistical results. However, duplicate records in a distributed dataset may lead to incorrect statistical results. Therefore, to increase the accuracy of the statistical analysis of a distributed dataset, secure deduplication is an important preprocessing step.
Methods
We designed a secure protocol for the deduplication of horizontally partitioned datasets with deterministic record linkage algorithms. We provided a formal security analysis of the protocol in the presence of semi-honest adversaries. The protocol was implemented and deployed across three microbiology laboratories located in Norway, and we ran experiments on the datasets in which the number of records for each laboratory varied. Experiments were also performed on simulated microbiology datasets and data custodians connected through a local area network.
Results
The security analysis demonstrated that the protocol protects the privacy of individuals and data custodians under a semi-honest adversarial model. More precisely, the protocol remains secure with the collusion of up to N − 2 corrupt data custodians. The total runtime for the protocol scales linearly with the addition of data custodians and records. One million simulated records distributed across 20 data custodians were deduplicated within 45 s. The experimental results showed that the protocol is more efficient and scalable than previous protocols for the same problem.
Conclusions
The proposed deduplication protocol is efficient and scalable for practical uses while protecting the privacy of patients and data custodians
Messenger RNA expression for the follicle-stimulating hormone receptor and luteinizing hormone receptor in human oocytes and preimplantation-stage embryos
Objective: To study the expression of the FSH and LH receptors in human
oocytes and preimplantation embryos and their potential roles in early
human development.
Design: Clinical and molecular studies.
Setting: University hospital IVF center. Patient(s): Female volunteers
undergoing intracytoplasmic sperm injection at the IVF unit of the
Athens University Hospital. All patients gave written informed consent.
Intervention(s): Ovarian stimulation was performed with exogenous
gonadotropin administration. Intracytoplasmic sperm injection was
performed on mature oocytes.
Main Outcome Measure(s): Unfertilized oocytes and zygotes and embryos at
the 2-cell, 4-cell, morula, and blastocyst stage were selected for
study. A polymerase chain reaction methodology was used to analyze human
oocytes and embryos. Messenger RNA was reverse transcribed and amplified
with FSH and LH receptor specific primers.
Result(s): Transcripts for the FSH receptor were detected in oocytes and
zygotes and embryos at the 2-cell, morula, and blastocyst stage, while
no message was detected in embryos at the 4-cell stage. Transcripts for
the LH receptor were observed in oocytes and zygotes and morula- and
blastocyst-stage embryos, whereas no message was detected in embryos at
the 2-cell and 4-cell stage.
Conclusion(s): Messenger RNA for the FSH and LH receptors was observed
in oocytes and preimplantation embryos at different stages, indicating a
physiological role in the oocyte maturation process and early embryonic
development in the human. (C) 2003 by American Society for Reproductive
Medicine
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