346 research outputs found

    Development of chip passivated monolithic complementary MISFET circuits with beam leads

    Get PDF
    Fabrication method is described for alumina passivated silicon MISFET arrays. Technique involves total passivation beam-lead approach and provides completely sealed chip with double level interconnect capability. Refractory metal alloy is used to form interconnect system and obtain metal contacts that withstand temperatures of 873 K for short periods of time

    Structure-Function Analysis of Escherichia coli DNA Helicase I Reveals Non-overlapping Transesterase and Helicase Domains

    Get PDF
    TraI (DNA helicase I) is an Escherichia coli F plasmid-encoded protein required for bacterial conjugative DNA transfer. The protein is a sequence-specific DNA transesterase that provides the site- and strand-specific nick required to initiate DNA strand transfer and a 5' to 3' DNA helicase that unwinds the F plasmid to provide the single-stranded DNA that is transferred from donor to recipient. Sequence comparisons with other transesterases and helicases suggest that these activities reside in the N- and C-terminal regions of TraI, respectively. Computer-assisted secondary structure probability analysis identified a potential interdomain region spanning residues 304-309. Proteins encoded by segments of traI, whose N or C terminus either flanked or coincided with this region, were purified and assessed for catalytic activity. Amino acids 1-306 contain the transesterase activity, whereas amino acids 309-1504 contain the helicase activity. The C-terminal 252 amino acids of the 1756-amino acid TraI protein are not required for either helicase or transesterase activity. Protein and nucleic acid sequence similarity searches indicate that the occurrence of both transesterase- and helicase-associated motifs in a conjugative DNA transfer initiator protein is rare. Only two examples (other than R100 plasmid TraI) were found: R388 plasmid TrwC and R46 plasmid (pKM101) TraH, belonging to the IncW and IncN groups of broad host range conjugative plasmids, respectively. The most significant structural difference between these proteins and TraI is that TraI contains an additional region of approximately 650 residues between the transesterase domain and the helicase-associated motifs. This region is required for helicase activity

    Optimizing the "Time to pregnancy" in women with multiple sclerosis: the OPTIMUS Delphi survey

    Get PDF
    Background: The debate on how to manage women affected by multiple sclerosis (MS) during reproductive age is still open, as is the issue of fertility in such patients. Main issue regard the identification of the optimal window for pregnancy and how to deal with medical therapy before and during conception. The aim of this Delphi consensus was to collect the opinions of a multidisciplinary group, involving reproductive medicine specialists and neurologists with experience in the management of multiple sclerosis women with reproductive desire. Methods: Four experts plus scientific coordinators developed a questionnaire distributed online to 10 neurologists and later discussed the responses and amended a list of statements. The statements were then distributed via an online survey to 23 neurologists (comprising the first 10), who voted on their level of agreement/disagreement with each statement. Consensus was achieved if agreement or disagreement with a statement exceeded 66%. Results: Twenty-one statements reached consensus after two rounds of voting, leading to the following main recommendations: (1) Fertility evaluation should be suggested to wMS, in case of the need to shorten time to pregnancy and before treatment switch in women on DMTs contraindicated in pregnancy, particularly in case of highly active disease and age > 35 years. (2) ART should not be discouraged in wMS, but the use of DMTs until pregnancy confirmation should be suggested; ART may be considered in order to reduce time to pregnancy in MS women with a reduced ovarian reserve and/or age > 35 years, but in case of an expected poor ART prognosis and the need for more than one ART cycle, a switch to a highefficacy DMD before ART should be offered. (3) Oocyte cryopreservation may be considered in women with reduced ovarian reserve, with unpredictable time to complete diagnostic workup and achieve disease control; a risk/cost–benefit analysis must be performed in women >35 years, considering the diminished ovarian reserve. Conclusion: This consensus will help MS neurologists to support family planning in wMS, respecting MS therapeutic needs while also taking into account the safety and impact of advancing age on fertility
    • …
    corecore