310 research outputs found
Quantum-limited directional amplifiers with optomechanics
Directional amplifiers are an important resource in quantum information
processing, as they protect sensitive quantum systems from excess noise. Here,
we propose an implementation of phase-preserving and phase-sensitive
directional amplifiers for microwave signals in an electromechanical setup
comprising two microwave cavities and two mechanical resonators. We show that
both can reach their respective quantum limits on added noise. In the reverse
direction, they emit thermal noise stemming from the mechanical resonators and
we discuss how this noise can be suppressed, a crucial aspect for technological
applications. The isolation bandwidth in both is of the order of the mechanical
linewidth divided by the amplitude gain. We derive the bandwidth and
gain-bandwidth product for both and find that the phase-sensitive amplifier has
an unlimited gain-bandwidth product. Our study represents an important step
toward flexible, on-chip integrated nonreciprocal amplifiers of microwave
signals
Формування індивідуального стилю у творчості народних майстрів художньої обробки дерева (на прикладі різьбярських династій Шкрібляків та Корпанюків)
У статті розглянуто творчість видатних різьбярських династій Шкрібляків та Корпанюків з позиції формування власного стилю в кожного з майстрів та їхнього впливу на зародження Косівської школи художньої обробки дерева. Особливу увагу приділено тим технічним і технологічним новаціям, які застосовували у своїх творах різьбярі, та тим композиційним прийомам, які вирізняли їхні вироби з-поміж інших.В статье рассматривается творчество выдающихся династий резчиков Шкрибляков и Корпанюков с точки зрения формирования собственного стиля у каждого из мастеров и их влияния на зарождение Косовской школы художественной обработки дерева. Особое внимание уделяется тем техническим и технологическим новациям, которые использовали резчики в своих произведениях, и композиционным приёмам, выделяющим их изделия среди прочих.There is an observation of creative work of the illustrious Shkribliak and K orpaniuk houses of carvers from a position of formation of a master’s individual style and proceeding from each master’s impact on the K osiv artistic carving school’s origin. The author pays a specific attention to the technical and technological innovations which are put into practice by a carver as well as to the composition wethods which differ carver’s wares from the rest
Role of the Helicobacter pylori outer-membrane proteins AlpA and AlpB in colonization of the guinea pig stomach
The human gastric pathogen Helicobacter pylori expresses several putative
outer-membrane proteins (OMPs), but the role of individual OMPs in
colonization of the stomach by H. pylori is still poorly understood. The
role of four such OMPs (AlpA, AlpB, OipA and HopZ) in a guinea pig model
of H. pylori infection has been investigated. Single alpA, alpB, hopZ and
oipA isogenic mutants were constructed in the guinea pig-adapted,
wild-type H. pylori strain GP15. Guinea pigs were inoculated
intragastrically with the wild-type strain, single mutants or a mixture of
the wild-type and a single mutant in a 1: 1 ratio. Three weeks after
infection, H. pylori could be isolated from stomach sections of all
animals that were infected with the wild-type, the hopZ mutant or the oipA
mutant, but from only five of nine (P = 0.18) and one of seven (P = 0.02)
animals that were infected with the alpA or alpB mutants, respectively.
The hopZ and oipA mutants colonized the majority of animals that were
inoculated with the strain mixture, whereas alpA and alpB mutants could
not be isolated from anim
MUC4 is increased in high-grade intraepithelial neoplasia in Barrett's oesophagus and is associated with a pro-apoptotic bax/bcl-2 ratio.
MUC4 is increased in high-grade intraepithelial neoplasia in Barrett's oesophagus and is associated with a pro-apoptotic bax/bcl-2 ratio.
Raman spectroscopy-based identification of nosocomial outbreaks of the clonal bacterium Escherichia coli
DNA-based techniques are frequently used to confirm the relatedness of putative outbreak isolates. These techniques often lack the discriminatory power when analyzing closely related microbes such as E. coli. Here the value of Raman spectroscopy as a typing tool for E. coli in a clinical setting was retrospectively evaluated
Does CDX2 expression predict Barrett's metaplasia in oesophageal columnar epithelium without goblet cells?
NikR mediates nickel-responsive transcriptional induction of urease expression in Helicobacter pylori
The important human pathogen Helicobacter pylori requires the abundant
expression and activity of its urease enzyme for colonization of the
gastric mucosa. The transcription, expression, and activity of H. pylori
urease were previously demonstrated to be induced by nickel
supplementation of growth media. Here it is demonstrated that the HP1338
protein, an ortholog of the Escherichia coli nickel regulatory protein
NikR, mediates nickel-responsive induction of urease expression in H.
pylori. Mutation of the HP1338 gene (nikR) of H. pylori strain 26695
resulted in significant growth inhibition of the nikR mutant in the
presence of supplementation with NiCl(2) at > or =100 microM, whereas the
wild-type strain tolerated more than 10-fold-higher levels of NiCl(2).
Mutation of nikR did not affect urease subunit expression or urease enzyme
activity in unsupplemented growth media. However, the nickel-induced
increase in urease subunit expression and urease enzyme activity observed
in wild-type H. pylori was absent in the H. pylori nikR mutant. A similar
lack of nickel responsiveness was observed upon removal of a 19-bp
palindromic sequence in the ureA promoter, as demonstrated by using a
genomic ureA::lacZ reporter gene fusion. In conclusion, the H. pylori NikR
protein and a 19-bp operator sequence in the ureA promoter are both
essential for nickel-responsive induction of urease expression in H.
pylori
Does CDX2 expression predict Barrett's metaplasia in oesophageal columnar epithelium without goblet cells?
Background: Intestinal metaplasia (Barrett's oesophagus), but not cardiac-type mucosa in columnar-lined oesophagus, is regarded as premalignant. As intestinal metaplasia and cardiac-type mucosa are endoscopically indiscernible, it is difficult to take targeted samples from columnar-lined oesophagus with consequently a risk of having undetected intestinal metaplasia. Aim: To investigate whether the intestinal markers CDX2, MUC2 and villin can predict the presence of undetected intestinal metaplasia in columnar-lined oesophagus. Methods: Presence of intestinal metaplasia or cardiac-type mucosa was identified in 122 biopsy sets of columnar-lined oesophagus from 61 patients, collected at two subsequent follow-up upper endoscopies. CDX2, MUC2 and villin expression were determined by immunohistochemistry. Results: All intestinal metaplasia samples (55) were positive for CDX2 and MUC2 and 32 of 55 for vil
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