5,905 research outputs found
Minimal Super Technicolor
We introduce novel extensions of the Standard Model featuring a
supersymmetric technicolor sector. First we consider N=4 Super Yang-Mills which
breaks to N=1 via the electroweak (EW) interactions and coupling to the MSSM.
This is a well defined, economical and calculable extension of the SM involving
the smallest number of fields. It constitutes an explicit example of a natural
supersymmetric conformal extension of the Standard Model featuring a well
defined connection to string theory. It allows to interpolate, depending on how
we break the underlying supersymmetry, between unparticle physics and Minimal
Walking Technicolor. As a second alternative we consider other N =1 extensions
of the Minimal Walking Technicolor model. The new models allow all the standard
model matter fields to acquire a mass.Comment: Improved version demonstrating that this extension is
phenomenologically viable. No Landau pole exists in the theory to two loops
level. This is the first theory showing that supersymmetry can solve the
flavor problem when coupled to low energy technicolo
A Perturbative Realization of Miransky Scaling
Near conformal dynamics is employed in different extensions of the standard
model of particle interactions as well as in cosmology. Many of its interesting
properties are either conjectured or determined using model computations. We
introduce a relevant four dimensional gauge theory template allowing us to
investigate such dynamics perturbatively. The gauge theory we consider is
quantum chromodynamics with the addition of a meson-like scalar degree of
freedom as well as an adjoint Weyl fermion.
At the two-loop level, and in the Veneziano limit, we firmly establish the
existence of several fixed points of which one is all directions stable in the
infrared. An interesting feature of the model is that this fixed point is lost,
within the perturbatively trustable regime, by merging with another fixed point
when varying the number of quark flavors. We show the emergence of the Miransky
scaling and determine its properties. We are also able to determine the walking
region of the theory which turns out to be, at large number of colors, about
12% of the conformal window. Furthermore, we determine highly relevant
quantities for near conformal dynamics such as the anomalous dimension of the
fermion masses.Comment: 17 pages, 8 figure
Endoluminal calprotectin measurement in assessment of pouchitis and a new index of disease activity. A pilot study
Pouchitis is the most common complication following proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis (UC). To provide a standardized definition of pouchitis clinical, endoscopic and histological markers were grouped and weighted in the pouch disease activity index (PDAI). However, the delay in the assessment of the final score due to the time requested for histological analysis remains the main obstacle to the index implementation in clinical practice so that the use of modified-PDAI (mPDAI) with exclusion of histologic subscore has been proposed. We tested the ability of calprotectin measurement in the pouch endoluminal content to mimic the histologic score as defined in the PDAI, the index that we adopted as gold standard for pouchitis diagnosis. Calprotectin was measured by ELISA in the pouch endoluminal content collected during endoscopy in 40 consecutive patients with J-pouch. In each patient PDAI and mPDAI were calculated and 15% of patients were erroneously classified by mPDAI. ROC analysis of calprotectin values vs. acute histological subscore 3 identified different calprotectin cut-off values with corresponding sensitivity and specificity allowing the definition and scoring of different range of calprotectin subscores. We incorporated the calprotectin score in the mPDAI obtaining a new score that shows the same specificity as PDAI for diagnosis of pouchitis and higher sensitivity when compared with mPDAI. The use of the proposed new score, once validated in a larger series of patients, might be useful in the early management of patients with symptoms of pouchitis
A horse, a horse, my kingdom for a horse. Saddle thrombosis of carotid bifurcation in acute stroke
Background: Saddle thrombosis is less frequently detected in carotid arteries than in peripheral arterial embolism. The clot and the distal vessel patency have to be promptly recognized in these cases, because if the carotid vessel is open distally, chances may arise for successful emergent surgical procedures to remove the thrombus. At conventional static imaging, mobile floating thrombi may be difficult to differentiate from thrombosis on carotid complicated lesions of atherosclerotic origin. High-resolution ultrasound (US), with its unique capability of real-time imaging, adds fundamental data for interpretation of the findings. Methods: Carotid ultrasound has been performed in acute stroke patients with high-resolution probes. Real-time clips are analyzed and imaging is presented. Results: Saddle carotid bifurcation thrombosis of cardiac origin has been identified in 2 patients with acute homolateral ischemic stroke, with prompt successful surgical removal in one case. Moreover, an example of a thrombus attached on the ruptured surface of a complicated atherosclerotic plaque in an acute symptomatic stroke patient that was successfully operated in emergency is presented. Conclusions: Early high-resolution ultrasound with real-time imaging can easily identify peculiar characteristics of carotid vulnerable diseases in acute stroke phase. Different clinical implications result from the early identification of these different conditions, modifying the therapeutical strategies. © 2012 Elsevier GmbH
Whole-exome analysis in osteosarcoma to identify a personalized therapy
Osteosarcoma is the most common pediatric primary non-hematopoietic bone
tumor. Survival of these young patients is related to the response to chemotherapy and
development of metastases. Despite many advances in cancer research, chemotherapy
regimens for osteosarcoma are still based on non-selective cytotoxic drugs. It is essential
to investigate new specific molecular therapies for osteosarcoma to increase the survival
rate of these patients. We performed exomic sequence analyses of 8 diagnostic biopsies
of patients with conventional high grade osteosarcoma to advance our understanding
of their genetic underpinnings and to correlate the genetic alteration with the clinical
and pathological features of each patient to identify a personalized therapy.
We identified 18,275 somatic variations in 8,247 genes and we found three
mutated genes in 7/8 (87%) samples (KIF1B, NEB and KMT2C). KMT2C showed the
highest number of variations; it is an important component of a histone H3 lysine 4
methyltransferase complex and it is one of the histone modifiers previously implicated
in carcinogenesis, never studied in osteosarcoma. Moreover, we found a group of 15
genes that showed variations only in patients that did not respond to therapy and
developed metastasis and some of these genes are involved in carcinogenesis and
tumor progression in other tumors.
These data could offer the opportunity to get a key molecular target to identify
possible new strategies for early diagnosis and new therapeutic approaches for
osteosarcoma and to provide a tailored treatment for each patient based on their
genetic profile
The abundant class of nemis repeats provides RNA substrates for ribonuclease III in Neisseriae
BCR-ABL residues interacting with ponatinib are critical to preserve the tumorigenic potential of the oncoprotein
Patients with chronic myeloid leukemia in whom tyrosine kinase inhibitors (TKIs) fail often present mutations in the BCR-ABL catalytic domain. We noticed a lack of substitutions involving 4 amino acids (E286, M318, I360, and D381) that form hydrogen bonds with ponatinib. We therefore introduced mutations in each of these residues, either preserving or altering their physicochemical properties. We found that E286, M318, I360, and D381 are dispensable for ABL and BCR-ABL protein stability but are critical for preserving catalytic activity. Indeed, only a "conservative" I360T substitution retained kinase proficiency and transforming potential. Molecular dynamics simulations of BCR-ABLI360T revealed differences in both helix αC dynamics and protein-correlated motions, consistent with a modified ATP-binding pocket. Nevertheless, this mutant remained sensitive to ponatinib, imatinib, and dasatinib. These results suggest that changes in the 4 BCR-ABL residues described here would be selected against by a lack of kinase activity or by maintained responsiveness to TKIs. Notably, amino acids equivalent to those identified in BCR-ABL are conserved in 51% of human tyrosine kinases. Hence, these residues may represent an appealing target for the design of pharmacological compounds that would inhibit additional oncogenic tyrosine kinases while avoiding the emergence of resistance due to point mutations.This work was supported by an investigator grant to P.V. from Associazione Italiana per la Ricerca sul Cancro
(AIRC) and by funding from the Biotechnology and Biological Sciences Research Council (BB/I023291/1 and
BB/H018409/1 to AP and FF). P.B. is the recipient of an AIRC - Marie Curie fellowship
The Role of Maintenance Operator in Industrial Manufacturing Systems: Research Topics and Trends
Maintenance contributes to gaining high business performance, guarantees system availability and reliability as well as safe and sustainable operations. Maintenance activity effectiveness depends on competences and the skills of operators whose performance strongly affects maintenance and production operations. The research field of human issues in industrial maintenance was deeply addressed in the literature; however, the current industrial paradigm, which focusses on the integration of new technologies in conventional manufacturing operations to support human performance, sheds light on new challenges for enterprises and opportunities for research in this field. While some literature reviews in the field of human errors and human factors are available, no study investigated the main topics, research trends and challenges related to the role of maintenance operators in manufacturing systems. This paper addresses the current state-of-the-art role of maintenance operators in manufacturing systems, providing an overview of the main studies. A systematic literature review was carried out to identify significant papers. Then, a topic modelling algorithm was used to detect the main topics of the selected papers to provide the research trends of the subject. The identified topics provided interesting research insights on the human role in industrial maintenance. Research trends and further research opportunities were defined
Enteral bleeding in a former preterm girl with short bowel syndrome: Do not miss the diagnosis
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