952 research outputs found
Searching for the Least Invasive Management of Pelvi-Ureteric Junction Obstruction in Children: A Critical Literature Review of Comparative Outcomes
Introduction: To review the published evidence on the minimally invasive pyeloplasty techniques available currently with particular emphasis on the comparative data about the various minimally invasive alternatives to treat pelvi-ureteric junction obstruction and gauge if one should be favored under certain circumstances. Materials and Methods: Non-systematic review of literature on open and minimally invasive pyeloplasty including various kinds of laparoscopic procedures, the robotic-assisted laparoscopic pyeloplasty, and endourological procedures. Results: Any particular minimally invasive pyeloplasty procedure seems feasible in experienced hands, irrespective of age including infants. Comparative data suggest that the robotic-assisted procedure has gained wider acceptance mainly because it is ergonomically more suited to surgeon well-being and facilitates advanced skills with dexterity thanks to 7 degrees of freedom. However, costs remain the major drawback of robotic surgery. In young children and infants, instead, open surgery can be performed via a relatively small incision and quicker time frame. Conclusions: The best approach for pyeloplasty is still a matter of debate. The robotic approach has gained increasing acceptance over the last years with major advantages of the surgeon well-being and ergonomics and the ease of suturing. Evidence, however, may favor the use of open surgery in infancy
Electron spin relaxation in semiconducting carbon nanotubes: the role of hyperfine interaction
A theory of electron spin relaxation in semiconducting carbon nanotubes is
developed based on the hyperfine interaction with disordered nuclei spins I=1/2
of C isotopes. It is shown that strong radial confinement of electrons
enhances the electron-nuclear overlap and subsequently electron spin relaxation
(via the hyperfine interaction) in the carbon nanotubes. The analysis also
reveals an unusual temperature dependence of longitudinal (spin-flip) and
transversal (dephasing) relaxation times: the relaxation becomes weaker with
the increasing temperature as a consequence of the particularities in the
electron density of states inherent in one-dimensional structures. Numerical
estimations indicate relatively high efficiency of this relaxation mechanism
compared to the similar processes in bulk diamond. However, the anticipated
spin relaxation time of the order of 1 s in CNTs is still much longer than
those found in conventional semiconductor structures.Comment: 11 pages, 2 figure
An Overview and Assessment of the Editorial Assistant Position at \u3ci\u3eWomenâs Studies Quarterly\u3c/i\u3e
This paper represents the culmination of my internship at Womenâs Studies Quarterly, and documents my experience of working from September 2020, to June 2021. I will begin with a discussion of the journalâs historical importance; from its origin in 1972, to its more contemporary issues. This background will segue into a critical analysis of my role at the journal, supported by anecdotes and ideas of critical feminist theorists
Entanglement in the interaction between two quantum oscillator systems
The fundamental quantum dynamics of two interacting oscillator systems are
studied in two different scenarios. In one case, both oscillators are assumed
to be linear, whereas in the second case, one oscillator is linear and the
other is a non-linear, angular-momentum oscillator; the second case is, of
course, more complex in terms of energy transfer and dynamics. These two
scenarios have been the subject of much interest over the years, especially in
developing an understanding of modern concepts in quantum optics and quantum
electronics. In this work, however, these two scenarios are utilized to
consider and discuss the salient features of quantum behaviors resulting from
the interactive nature of the two oscillators, i.e., coherence, entanglement,
spontaneous emission, etc., and to apply a measure of entanglement in analyzing
the nature of the interacting systems. ... For the coupled linear and
angular-momentum oscillator system in the fully quantum-mechanical description,
we consider special examples of two, three, four-level angular momentum
systems, demonstrating the explicit appearances of entanglement. We also show
that this entanglement persists even as the coupled angular momentum oscillator
is taken to the limit of a large number of levels, a limit which would go over
to the classical picture for an uncoupled angular momentum oscillator
Laparoscopic Left Adrenalectomy with Submesocolic and Retropancreatic Approach
Introduction: The safety and efficacy of laparoscopic transperitoneal lateral adrenalectomy and retroperitoneoscopic adrenalectomy have been reported. The aim is to report the authorsâ experience in laparoscopic left adrenalectomy with an alternative transperitoneal submesocolic and retropancreatic approach with patient supine
Is there any clinical relevant difference between non mosaic Klinefelter Syndrome patients with or without Androgen Receptor variations?
Klinefelter Syndrome (KS) is the most common chromosomal disorder in men leading to non-obstructive azoospermia. Spermatozoa can be found by TESE in about 50% of adults with KS despite severe testicular degeneration. We evaluated AR variations and polymorphism length in 135 non-mosaic KS patients, aimed to find possible correlation with clinical features, sex hormones and sperm retrieval. Among 135 KS patients we found AR variations in eight subjects (5.9%). All variations but one caused a single amino acid substitution. Four variations P392S, Q58L, L548F, A475V found in six patients had been previously described to be associated with different degrees of androgen insensitivity. Moreover we observed in two patients Y359F and D732D novel variations representing respectively a missense variation and a synonymous variation not leading to amino acid substitution. All the Klinefelter patients with AR gene variations were azoospermic. Spermatozoa were retrieved with TESE for two men (40%), sperm retrieval was unsuccessful in other 3 patients. This is the only study reporting AR variations in KS patients. Relevant clinical differences not emerged between AR mutated and not AR mutated KS patients, but does each variation play an important role in the trasmission to the offspring obtained by ART in this patients
Drift-diffusion model for spin-polarized transport in a non-degenerate 2DEG controlled by a spin-orbit interaction
We apply the Wigner function formalism to derive drift-diffusion transport
equations for spin-polarized electrons in a III-V semiconductor single quantum
well. Electron spin dynamics is controlled by the linear in momentum spin-orbit
interaction. In a studied transport regime an electron momentum scattering rate
is appreciably faster than spin dynamics. A set of transport equations is
defined in terms of a particle density, spin density, and respective fluxes.
The developed model allows studying of coherent dynamics of a non-equilibrium
spin polarization. As an example, we consider a stationary transport regime for
a heterostructure grown along the (0, 0, 1) crystallographic direction. Due to
the interplay of the Rashba and Dresselhaus spin-orbit terms spin dynamics
strongly depends on a transport direction. The model is consistent with results
of pulse-probe measurement of spin coherence in strained semiconductor layers.
It can be useful for studying properties of spin-polarized transport and
modeling of spintronic devices operating in the diffusive transport regime.Comment: 16 pages, 3 figure
Pindel: a pattern growth approach to detect break points of large deletions and medium sized insertions from paired-end short reads
Motivation: There is a strong demand in the genomic community to develop effective algorithms to reliably identify genomic variants. Indel detection using next-gen data is difficult and identification of long structural variations is extremely challenging
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