368 research outputs found
A case of a GH-producing pituitari adenoma associated with a unilateral headache with autonomic signs.
A 66âyearâold man suffered from a drugâresistant, leftsided headache with autonomic signs, triggered by the supine position. The acromegalic facies initially suggested a possible increase in basal plasma levels of GH, but routine haematological controls excluded abnormal values of GH. Cerebral and facial CT scan and MRI did not detect any alterations in the nasal sinuses, except for a mucous cyst. Surgical ablation of the cyst did not alleviate the pain. Further endocrinological tests demonstrated an increase of IGFâ1 (somatomedin C), and another MRI scan of the sellar region confirmed the presence of a pituitary macroadenoma on the left paramedian side. After an initial improvement of the symptomatology due to transâsphenoidal ablation of a benign GHâproducing macroadenoma, the headache worsened again. Pain was well correlated with the increased plasma levels of IGFâ1. The patient died suddenly for myocardial infarct
Towards realistic laparoscopic image generation using image-domain translation
Background and ObjectivesOver the last decade, Deep Learning (DL) has revolutionized data analysis in many areas, including medical imaging. However, there is a bottleneck in the advancement of DL in the surgery field, which can be seen in a shortage of large-scale data, which in turn may be attributed to the lack of a structured and standardized methodology for storing and analyzing surgical images in clinical centres. Furthermore, accurate annotations manually added are expensive and time consuming. A great help can come from the synthesis of artificial images; in this context, in the latest years, the use of Generative Adversarial Neural Networks (GANs) achieved promising results in obtaining photo-realistic images. MethodsIn this study, a method for Minimally Invasive Surgery (MIS) image synthesis is proposed. To this aim, the generative adversarial network pix2pix is trained to generate paired annotated MIS images by transforming rough segmentation of surgical instruments and tissues into realistic images. An additional regularization term was added to the original optimization problem, in order to enhance realism of surgical tools with respect to the background. Results Quantitative and qualitative (i.e., human-based) evaluations of generated images have been carried out in order to assess the effectiveness of the method. ConclusionsExperimental results show that the proposed method is actually able to translate MIS segmentations to realistic MIS images, which can in turn be used to augment existing data sets and help at overcoming the lack of useful images; this allows physicians and algorithms to take advantage from new annotated instances for their training
Theoretical study of the (3x2) reconstruction of beta-SiC(001)
By means of ab initio molecular dynamics and band structure calculations, as
well as using calculated STM images, we have singled out one structural model
for the (3x2) reconstruction of the Si-terminated (001) surface of cubic SiC,
amongst several proposed in the literature. This is an alternate dimer-row
model, with an excess Si coverage of 1/3, yielding STM images in good accord
with recent measurements [F.Semond et al. Phys. Rev. Lett. 77, 2013 (1996)].Comment: To be published in PRB Rapid. Com
TRANSPERITONEAL LAPAROSCOPIC ADRENALECTOMY IN CHILDREN: INITIAL EXPERIENCE
PURPOSE: The use of mini-invasive approach for adrenalectomy is poorly defined in pediatric
patients, although laparoscopic adrenalectomy is considered a standard procedure in adults. The
aim of our study is to describe the safety and feasibility of minimally invasive adrenalectomy in
children based on surgical skills and results.
MATERIALS AND METHODS: This is a retrospective study of four pediatric laparoscopic
adrenalectomies performed in our centre between 2009 and 2012. All patients underwent
transperitoneal lateral laparoscopic adrenalectomy two of which were right adrenalectomies and
two were left.
RESULTS: Four laparoscopic adrenalectomies were performed. Indications for surgery were
neuroblastoma in two patients, secernent adrenocortical tumor in one patient and adrenocortical
nodular hyperplasia in the last one. Patients had a mean age of 87 months (range 17-156) at
diagnosis and the average lesion size was 3.23 cm (range 0.7-6.4). All laparoscopic
adrenalectomies were successful, no conversions to open surgery were required and no post-
operative complications or deaths occurred. The average operating time was 105 minutes (range
80-130), blood loss during surgery was minimal and the mean post-operative hospital stay was
3.75 days (range 3-5). None of the patients showed signs of recurring disease at 15-months follow-
up.
CONCLUSIONS: Laparoscopic adrenalectomy is a safe, feasible and reproducible technique
offering numerous advantages including shortening of operating times and post-operative hospital
stays, as well as reduction of blood loss and complications. It also provides good visibility and easy
access to other organs
High-density molecular characterization and association mapping in Ethiopian durum wheat landraces reveals high diversity and potential for wheat breeding
Durum wheat (Triticum turgidum subsp. durum) is a key crop worldwide, and yet, its improvement and adaptation to emerging environmental threats is made difïŹcult by the limited amount of allelic variation included in its elite pool. New allelic diversity may provide novel loci to international crop breeding through quantitative trait loci (QTL) mapping in unexplored material.
Here, we report the extensive molecular and phenotypic characterization of hundreds of Ethiopian durum wheat landraces and several Ethiopian improved lines. We test 81 587 markers scoring 30 155 single nucleotide polymorphisms and use them to survey the diversity, structure, and genome-speciïŹc variation in the panel. We show the uniqueness of Ethiopian germplasm
using a siding collection of Mediterranean durum wheat accessions. We phenotype the Ethiopian panel for ten agronomic traits in two highly diversiïŹed Ethiopian environments for two consecutive years and use this information to conduct a genome-wide association study. We identify several loci underpinning agronomic traits of interest, both conïŹrming loci already reported and describing new promising genomic regions. These loci may be efïŹciently targeted with molecular markers already available to conduct marker-assisted selection in Ethiopian and international wheat. We show that Ethiopian durum wheat represents an important and mostly unexplored source of durum wheat diversity. The panel analysed in this study allows the accumulation of QTL mapping experiments, providing the initial step for a quantitative, methodical exploitation of untapped diversity in producing a better wheat
Dynamical-charge neutrality at a crystal surface
For both molecules and periodic solids, the ionic dynamical charge tensors
which govern the infrared activity are known to obey a dynamical neutrality
condition. This condition enforces their sum to vanish (over the whole finite
system, or over the crystal cell, respectively). We extend this sum rule to the
non trivial case of the surface of a semiinfinite solid and show that, in the
case of a polar surface of an insulator, the surface ions cannot have the same
dynamical charges as in the bulk. The sum rule is demonstrated through
calculations for the Si-terminated SiC(001) surface.Comment: 4 pages, latex file, 1 postscript figure automatically include
Nature of bonding and electronic structure in MgB2, a boron intercalation superconductor
Chemical bonding and electronic structure of MgB2, a boron-based newly
discovered superconductor, is studied using self-consistent band structure
techniques. Analysis of the transformation of the band structure for the
hypothetical series of graphite - primitive graphite - primitive graphite-like
boron - intercalated boron, shows that the band structure of MgB2 is
graphite-like, with pi-bands falling deeper than in ordinary graphite. These
bands possess a typically delocalized and metallic, as opposed to covalent,
character. The in-plane sigma-bands retain their 2D covalent character, but
exhibit a metallic hole-type conductivity. The coexistence of 2D covalent
in-plane and 3D metallic-type interlayer conducting bands is a peculiar feature
of MgB2. We analyze the 2D and 3D features of the band structure of MgB2 and
related compounds, and their contributions to conductivity.Comment: 4 pages in revtex, 3 figures in 4 separate EPS file
Reconstruction and thermal stability of the cubic SiC(001) surfaces
The (001) surfaces of cubic SiC were investigated with ab-initio molecular
dynamics simulations. We show that C-terminated surfaces can have different
c(2x2) and p(2x1) reconstructions, depending on preparation conditions and
thermal treatment, and we suggest experimental probes to identify the various
reconstructed geometries. Furthermore we show that Si-terminated surfaces
exhibit a p(2x1) reconstruction at T=0, whereas above room temperature they
oscillate between a dimer row and an ideal geometry below 500 K, and sample
several patterns including a c(4x2) above 500 K.Comment: 12 pages, RevTeX, figures 1 and 2 available in gif form at
http://irrmawww.epfl.ch/fg/sic/fig1.gif and
http://irrmawww.epfl.ch/fg/sic/fig2.gi
Theoretical investigations of a highly mismatched interface: the case of SiC/Si(001)
Using first principles, classical potentials, and elasticity theory, we
investigated the structure of a semiconductor/semiconductor interface with a
high lattice mismatch, SiC/Si(001). Among several tested possible
configurations, a heterostructure with (i) a misfit dislocation network pinned
at the interface and (ii) reconstructed dislocation cores with a carbon
substoichiometry is found to be the most stable one. The importance of the slab
approximation in first-principles calculations is discussed and estimated by
combining classical potential techniques and elasticity theory. For the most
stable configuration, an estimate of the interface energy is given. Finally,
the electronic structure is investigated and discussed in relation with the
dislocation array structure. Interface states, localized in the heterostructure
gap and located on dislocation cores, are identified
CHALLENGE TESTS WITH LISTERIA MONOCYTOGENES IN SALAMI: PRELIMINARY RESULTS
Challenge tests are the preferable methodology to study the behaviour of Listeria monocytogenes on ready to eat foods, according to Regulation (EC) 2073/2005. Challenge testing using L. monocytogenes in seasoned salami from different food business operators showed, after seasoning of the product, a count reduction of the inoculated organisms without any further growth of the pathogen; however differences of L. monocytogenes behaviour could be observed according to different production protocols
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