546 research outputs found
Multiconfiguration time-dependent Hartree impurity solver for nonequilibrium dynamical mean-field theory
Nonequilibrium dynamical mean-field theory (DMFT) solves correlated lattice
models by obtaining their local correlation functions from an effective model
consisting of a single impurity in a self-consistently determined bath. The
recently developed mapping of this impurity problem from the Keldysh time
contour onto a time-dependent single-impurity Anderson model (SIAM) [C. Gramsch
et al., Phys. Rev. B 88, 235106 (2013)] allows one to use wave function-based
methods in the context of nonequilibrium DMFT. Within this mapping, long times
in the DMFT simulation become accessible by an increasing number of bath
orbitals, which requires efficient representations of the time-dependent SIAM
wave function. These can be achieved by the multiconfiguration time-dependent
Hartree (MCTDH) method and its multi-layer extensions. We find that MCTDH
outperforms exact diagonalization for large baths in which the latter approach
is still within reach and allows for the calculation of SIAMs beyond the system
size accessible by exact diagonalization. Moreover, we illustrate the
computation of the self-consistent two-time impurity Green's function within
the MCTDH second quantization representation.Comment: 12 pages, 8 figure
PreparaciĂłn de pĂ©ptidos protegidos en fase sĂłlida para una sĂntesis convergente
Treballs Finals de Grau de QuĂmica, Facultat de QuĂmica, Universitat de Barcelona, Any: 2019, Tutor: Ernesto Nicolás GalindoNowadays, the interest on the use of peptides as drugs is increasing due to their unique properties, such as high selectivity and low toxicity. As a result, pharmaceutical industry has more than 500 peptides that are currently in preclinical development and it is estimated that the peptides market involves 25.4 million dollars per year.1
This project was carried out in the Smbiocom research group, which collaborates with a pharmaceutical company which aims to synthetize a bioactive peptide with oncological properties and scale the method up to a pilot plant production. The strategy taken in the laboratory has consisted on a convergent synthesis of a fragment with eleven amino acids of the target peptide. In the first place, different peptide fragments have been synthetized in solid phase and finally they have been coupled in solution.
Five different protected peptide fragments of 4, 5, 6 and 9 amino acids have been synthetized by solid-phase methodology using the Fmoc/tBu strategy (1.2 mmol, 1.9 mmol, 1.1 mmol and 1.8 mmol scales) with a 2-CTC solid support resin. The reactions have been carried out using DIC as a coupling reagent, HOBt as an additive and finally each fragment has been characterized by HPLC-MS using reverse phase chromatography.
Furthermore, the C-terminal protected dipeptide fragment of the target peptide has been synthetized in solution and has been coupled to the nonapeptide in solution. The resulting full protected undecapeptide has been characterized by HPLC-M
Black hole elasticity and gapped transverse phonons in holography
We study the elastic response of planar black hole (BH) solutions in a simple
class of holographic models with broken translational invariance. We compute
the transverse quasi-normal mode spectrum and the propagation speed of the
lowest energy mode. We find that the speed of the lowest mode relates to the BH
rigidity modulus as dictated by elasticity theory. This allows to identify
these modes as transverse phonons---the pseudo Goldstone bosons of
spontaneously broken translational invariance. In addition, we show that these
modes have a mass gap controlled by an explicit source of the translational
symmetry breaking. These results provide a new confirmation that the BHs in
these models do exhibit solid properties that become more manifest at low
temperatures. Also, by the AdS/CFT correspondence, this allows to extend the
standard results from the effective field theory for solids to quantum-critical
materials.Comment: 28 pages, 7 figures; v3: minor revisions, matching JHEP published
versio
C to O-O Translation: Beyond the Easy Stuff
Can we reuse some of the huge code-base developed in C to take advantage of
modern programming language features such as type safety, object-orientation,
and contracts? This paper presents a source-to-source translation of C code
into Eiffel, a modern object-oriented programming language, and the supporting
tool C2Eif. The translation is completely automatic and supports the entire C
language (ANSI, as well as many GNU C Compiler extensions, through CIL) as used
in practice, including its usage of native system libraries and inlined
assembly code. Our experiments show that C2Eif can handle C applications and
libraries of significant size (such as vim and libgsl), as well as challenging
benchmarks such as the GCC torture tests. The produced Eiffel code is
functionally equivalent to the original C code, and takes advantage of some of
Eiffel's object-oriented features to produce safe and easy-to-debug
translations
Trachoma and Yaws: Common Ground?
Trachoma is an important cause of blindness. The causative organism is an intracellular bacterium, Chlamydia trachomatis, which is susceptible to single-dose azithromycin. A World Health Organization (WHO)-led program aims to eliminate trachoma as a public health problem globally by 2020. Yaws is a cause of skin, bone, and cartilage disease. The causative organism is a spirochaete bacterium, Treponema pallidum ssp. pertenue, which is susceptible to single-dose azithromycin. A WHO-led program aims to eradicate yaws globally by 2020
Simultaneous bilateral dual mobility total hip arthroplasty dislocation in a patient with hepatic encephalopathy: A case report
LuxaciĂł; Mobilitat dual; Encefalopatia hepĂ ticaDislocaciĂłn; Movilidad dual; EncefalopatĂa hepáticaDislocation; Dual mobility; Hepatic encephalopathyIntroduction and importance
Dislocation is a severe complication after total hip arthroplasty (THA). It is one of the most common reasons for failure and revision surgery. This is the first case of a documented simultaneous bilateral dual mobility (DM) THA dislocation.
Case presentation
A forty-nine-year-old man presented with bilateral hip pain, immobility and deformity. X-ray images demonstrated simultaneous bilateral posterior THA dislocation. Previously, the patient had presented atraumatic dislocations recurrently. When he was thoroughly re-interrogated, he complained of uncontrolled and generalized muscle contractions, which were compatible with myoclonus due to hepatic encephalopathy (HE). Multidisciplinary treatment was performed satisfactorily to control myoclonus symptomatology and to prevent dislocation.
Clinical discussion
Patient’s most important risk factor was a neuromuscular disorder, which we initially gave little notice and undervalued. HE is a serious but reversible syndrome, observed in patients with liver dysfunction. It leads to a wide spectrum of neuropsychiatric abnormalities. Management is based on prevention of episodes, avoiding the underlying triggers.
Due to the high risk for dislocation of our patient, we decided to use DM cups bilaterally. This system has demonstrated lower rates of dislocation.
Conclusion
This case report reminds us that a careful evaluation through meticulous history and physical examination are mandatory when faced with recurrent instability. Furthermore, prevention of dislocation is vastly preferable to treating this challenging complication. High-risk patients should be identified, and appropriate surgical approach, technique and implants have to be collectively used to reach a strategy that mitigates and ideally prevents dislocation
Outcome Predictors in Treatment of Yaws
To estimate failure rates after treatment with benzathine penicillin and to identify determinants of failure that affected outcomes for yaws, we conducted a cohort study of 138 patients; treatment failed in 24 (17.4%). Having low initial titers on Venereal Disease Research Laboratory test and living in a village where yaws baseline incidence was high were associated with increased likelihood of treatment failure
Isolation of Key Organometallic Aryl-Co(III) Intermediates in Cobalt-Catalyzed C(sp2)–H Functionalizations and New Insights into Alkyne Annulation Reaction Mechanisms
The selective annulation reaction of alkynes with substrates containing inert C–H bonds using cobalt as catalyst is currently a topic attracting significant interest. Unfortunately, the mechanism of this transformation is still relatively poorly understood, with little experimental evidence for intermediates, although an organometallic Co(III) species is generally implicated. Herein, we describe a rare example of the preparation and characterization of benchtop-stable organometallic aryl-Co(III) compounds (NMR, HRMS, XAS, and XRD) prepared through a C(sp2)–H activation, using a model macrocyclic arene substrate. Furthermore, we provide crystallographic evidence of an organometallic aryl-Co(III) intermediate proposed in 8-aminoquinoline-directed Co-catalyzed C–H activation processes. Subsequent insights obtained from the application of our new organometallic aryl-Co(III) compounds in alkyne annulation reactions are also disclosed. Evidence obtained from the resulting regioselectivity of the annulation reactions and DFT studies indicates that a mechanism involving an organometallic aryl-Co(III)-alkynyl intermediate species is preferred for terminal alkynes, in contrast to the generally accepted migratory insertion pathway
Professional Liability in Plastic Surgery: A Change of Scenario in Medical Professional Liability in Spain
Background:The epidemic of complaints and/or litigation, both in and out of court, for cases of alleged malpractice has increased dramatically. In Spain, claims related to plastic surgery are gaining more and more interest. Methods:The Council of Medical Associations of Catalonia database was used to analyze claims related to plastic surgery from 1986 to 2021. Results:1039 claims (9.8% over 10,567 total claims) were studied. Both the total number of claims (P = 0.016; R-2=0.16) and the number of claims for plastic surgery (P < 0.0005; R-2=0.732) showed an upward trend during the period of study. In the period from 2000 to 2021, the behavior was different; while the number of total claims stabilized (P = 0.352; R-2 = 0.043), plastic surgery claims continued to show a time-related tendency to increase (P < 0.0005; R-2=0.484). The distribution was 50.12% out of court. Ten unique procedures accounted for 84.5% of the total number of claims. Liability was observed in 21.46% of the closed claims, with differences between civil (20.34%), criminal (6.89%), and out-of-court (25.53%) procedures. Regarding compensation amounts, out-of-court cases had an average of 33,169.44 euros paid; civil cases, 29,153.37 euros; and criminal cases, 37,186.88 euros. Conclusions:The increase in the number of cases can only be related to an increase in the activity carried out by plastic surgeons. There has been a change in Spain in terms of the most sought-after medical specialty, with plastic surgery having displaced the perennially most sought-after specialty, orthopedic surgery and traumatology
- …