452 research outputs found
Extremal metrics on blow ups
Given a compact Kahler manifold with an extremal metric (M,\omega), we give
sufficient conditions on finite sets points p_1,...,p_n and weights a_1,...a_n
for which the blow up of M at p_1,...,p_n has an extremal metric in the Kahler
class \pi^*[\omega] - \epsilon (a_1 PD[E_1] + .. + a_n PD[E_n]) for all
\epsilon sufficiently small. In particular our result implies that if
(M,\omega) is a toric manifold and p_1,...,p_n is any subset of the fixed locus
of the torus action, then such metrics exist for any choice of the weights. The
relationship with previous constructions of the first two authors for Kahler
constant scalar curvature metrics is discussed.Comment: 39 page
Efficacy and safety of pregabalin 600 mg/d for treating painful diabetic peripheral neuropathy: A double-blind placebo-controlled trial
Balanced metrics on Cartan and Cartan-Hartogs domains
This paper consists of two results dealing with balanced metrics (in S.
Donaldson terminology) on nonconpact complex manifolds. In the first one we
describe all balanced metrics on Cartan domains. In the second one we show that
the only Cartan-Hartogs domain which admits a balanced metric is the complex
hyperbolic space. By combining these results with those obtained in [13]
(Kaehler-Einstein submanifolds of the infinite dimensional projective space, to
appear in Mathematische Annalen) we also provide the first example of complete,
Kaehler-Einstein and projectively induced metric g such that is not
balanced for all .Comment: 11 page
A magnetic internal mechanism for precise orientation of the camera in wireless endoluminal applications
Background and study aims: The use of magnetic
fields to control operative devices has been recently
described in endoluminal and transluminal
surgical applications. The exponential decrease of
magnetic field strength with distance has major
implications for precision of the remote control.
We aimed to assess the feasibility and functionality
of a novel wireless miniaturized mechanism,
based on magnetic forces, for precise orientation
of the camera.
Materials and methods: A remotely controllable
endoscopic capsule was developed as proof of
concept. Two intracapsular moveable permanent
magnets allow fine positioning, and an externally
applied magnetic field permits gross movement
and stabilization. Performance was assessed in ex
vivo and in vivo bench tests, using porcine upper
and lower gastrointestinal tracts.
Results: Fine control of capsule navigation and
rotation was achieved in all tests with an external
magnet held steadily about 15 cm from the capsule.
The camera could be rotated in steps of 1.8°.
This was confirmed by ex vivo tests; the mechanism
could adjust the capsule view at 40 different
locations in a gastrointestinal tract phantom
model. Full 360° viewing was possible in the gastric
cavity, while the maximal steering in the colonwas
45° in total. In vivo, a similar performance
was verified, where the mechanism was successfully
operated every 5 cm for 40 cm in the colon,
visually sweeping from side to side of the lumen;
360° views were obtained in the gastric fundus
and body, while antrally the luminal walls prevented
full rotation.
Conclusions: We report the feasibility and effectiveness
of the combined use of external static
magnetic fields and internal actuation to move
small permanent intracapsular magnets to
achieve wirelessly controllable and precise camera
steering. The concept is applicable to capsule
endoscopy as to other instrumentation for laparoscopic,
endoluminal, or transluminal procedures
Hpv-negative cervical cancer: A narrative review
Cervical cancer (CC) is the fourth most frequent cancer in women worldwide. HPV infection is associated with the majority of CC cases, but a small proportion of CCs actually test negative for HPV. The prevalence of HPV among CC histotypes is very different. It has been suggested that HPV-negative CC may represent a biologically distinct subset of tumors, relying on a distinct pathogenetic pathway and carrying a poorer prognosis, than HPV-positive CCs. Although, the discordance in terms of sensitivity and specificity between different HPV tests as well as the potential errors in sampling and storing tissues may be considered as causes of false-negative results. The identification of HPV-negative CCs is essential for their correct management. The aim of this narrative review is to summarize the clinical and pathological features of this variant. We also discuss the pitfalls of different HPV tests possibly leading to classification errors
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