Tuning the decay of sound in a viscous metamaterial.

Using analytical results for viscous dissipation in phononic crystals, we calculate the decay coefficient of a sound wave propagating at low frequencies through a two-dimensional phononic crystal with a viscous fluid background. It is demonstrated that the effective acoustic viscosity of the phononic crystal may exceed by two to four orders of magnitude the natural hydrodynamic viscosity of the background fluid. Moreover, the decay coefficient exhibits dependence on the direction of propagation; that is, a homogenized phononic crystal behaves like an anisotropic viscous fluid. Strong dependence on the filling fraction of solid scatterers offers the possibility of tuning the dissipative decay length of sound, which is an important characteristic of any acoustic device. This article is part of the theme issue 'Wave generation and transmission in multi-scale complex media and structured metamaterials (part 2)'.

The Role of Flaviviral Proteins in the Induction of Innate Immunity.

Flaviviruses are positive, single-stranded, enveloped cytoplasmic sense RNA viruses that cause a variety of important diseases worldwide. Among them, Zika virus, West Nile virus, Japanese encephalitis virus, and Dengue virus have the potential to cause severe disease. Extensive studies have been performed to elucidate the structure and replication strategies of flaviviruses, and current studies are aiming to unravel the complex molecular interactions between the virus and host during the very early stages of infection. The outcomes of viral infection and rapid establishment of the antiviral state, depends on viral detection by pathogen recognition receptors and rapid initiation of signalling cascades to induce an effective innate immune response. Extracellular and intracellular pathogen recognition receptors play a crucial role in detecting flavivirus infection and inducing a robust antiviral response. One of the main hallmarks of flaviviral nonstructural proteins is their multiple strategies to antagonise the interferon system. In this chapter, we summarize the molecular characteristics of flaviviral proteins and discuss how viral proteins target different components of the interferon signalling pathway by blocking phosphorylation, enhancing degradation, and downregulating the expression of major components of the Janus kinase/signal transducer and activator of transcription pathway. We also discuss how the interactions of viral proteins with host proteins facilitate viral pathogenesis. Due to the lack of antivirals or prophylactic treatments for many flaviviral infections, it is necessary to fully elucidate how these viruses disrupt cellular processes to influence pathogenesis and disease outcomes.

Nonreciprocal Linear Transmission of Sound in a Viscous Environment with Broken P Symmetry.

Reciprocity is a fundamental property of the wave equation in a linear medium that originates from time-reversal symmetry, or T symmetry. For electromagnetic waves, reciprocity can be violated by an external magnetic field. It is much harder to realize nonreciprocity for acoustic waves. Here we report the first experimental observation of linear nonreciprocal transmission of ultrasound through a water-submerged phononic crystal consisting of asymmetric rods. Viscosity of water is the factor that breaks the T symmetry. Asymmetry, or broken P symmetry along the direction of sound propagation, is the second necessary factor for nonreciprocity. Experimental results are in agreement with numerical simulations based on the Navier-Stokes equation. Our study demonstrates that a medium with broken PT symmetry is acoustically nonreciprocal. The proposed passive nonreciprocal device is cheap, robust, and does not require an energy source.

Oral management of children with Henoch-Schönlein Purpura and associated Glomerulonephritis: a scoping review.

AIM: To perform a scoping review of the existing literature in order to gather the most relevant information in the paediatric dentistry field related to the oral management of children affected by Henoch-Schönlein Purpura and associated Glomerulonephritis (HSPG). MATERIALS AND METHODS: Using scoping review methodology for the screening and selection of valid articles, the steps of this review were the following: first, to pose a research question; second, to identify relevant studies; third, to select and retrieve the studies; fourth, to chart the critical data, and finally, to collate, summarise, and report the results from the included articles. Relevant articles published over a 25-year period, up to July 31, 2017, were identified and retrieved from four Internet databases: PubMed; EMBASE/Ovid; Ebsco/Dentistry & Oral Science Source, and the Cochrane Collaboration Library. RESULTS: By title and abstract screening and after removing duplicates, four articles were finally included in the scoping review. According to the extracted data, the following are the most important clinical issues to be considered: (1) the disease can appear as a consequence of a dental treatment, such as those indicated for oral infectious processes; (2) children with HSPG are highly susceptible to dental caries and apical periodontitis, and (3) in affected children, oral infectious foci must be exhaustively eradicated in order to avoid the dissemination of the infection. CONCLUSIONS: Paediatric Dentists should be aware of HSPG, because the disease can be triggered or worsen subsequent to dental treatment. Adequate treatment of oral active infectious processes, together with an exhaustive oral preventive programme and long-term patient screening, are the best management approaches for children with HSPG.

In vitro leishmanicidal and trypanocidal evaluation and magnetic properties of 7-amino-1,2,4-triazolo[1,5-a]pyrimidine Cu(II) complexes.

Two triazolopyrimidine complexes have been obtained from reaction between 7-amino-1,2,4-triazolo[1,5-a]pyrimidine (7atp) and Cu (II) salts. Crystal structures of [Cu2(µ-7atp)4Cl2]Cl2·4H2O (1) and [Cu2(µ-7atp)4(H2O)2](NO3)4·H2O (2) have been studied by X-ray diffraction methods and characterized by spectroscopic and thermal analysis. Magnetic studies of these dinuclear complexes have revealed the existence of moderate antiferromagnetic interactions between the copper ions, with J values of -91.2 and -96.1cm-1 respectively. It must be highlighted that the antiparasitic activity of these new complexes has been studied in vitro against three different strains of leishmania spp. and Trypanosoma cruzi, showing a higher efficacy than the 7atp ligand and the reference commercial drugs.

Antiparasitic activity against trypanosomatid diseases and novel metal complexes derived from the first time characterized 5-phenyl-1,2,4-triazolo[1,5-a]pyrimidi-7(4H)-one.

A serie of isostructural complexes with general formula [M(ftpO)2(H2O)4] have been obtained from reaction between the first time characterized triazolopyrimidine derivative 5-phenyl-1,2,4-triazolo[1,5-a]pyrimidi-7(4H)-one (HftpO) (1) and first row transition nitrates (M=Cu (2), Co (3), Ni (4) and Zn (5)). A copper complex with formula [Cu(HftpO)2(NO3)2(H2O)2]·H2O (6) was also isolated. HftpO and their metal complexes have been characterized by spectroscopic and thermal analysis and their crystal structures have been solved by X-ray diffraction methods. The isostructural compounds are mononuclear complexes where the triazolopyrimidine ligand acts as monodentate ligand through N3 nitrogen position. The crystal structure of these novel bis-5-phenyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one-tetraaquo metal complexes offers an excellent opportunity at these complexes to acts as potential building blocks. Also, the antiparasitic activity of HftpO ligand against different leishmania and trypanosome strains has been studied.

Goos-Hänchen effect for optical vibrational modes in a semiconductor structure.

We study the tunneling of optical vibrational modes with transverse horizontal polarization that impinge, at a given angle, on a semiconductor heterostructure. We find a large influence of the Goos-Hänchen shift on tunneling times. In particular, a Goos-Hänchen shift larger than the barrier thickness is reported for the first time. The relation between Goos-Hänchen and Hartman effects is also discussed. The identity that equals the dwell time to the sum of transmission and interference times, previously derived for one-dimensional tunneling problems, is extended to the two-dimensional case. Closed-form expressions are developed for the relevant quantities. Instead of using the standard approach, the interference time is computed from the vibrational energy density. The present study could be useful for the design of semiconductor devices.

Chirped dual periodic structures for photonic Bloch oscillations and Zener tunneling.

Experimental evidence of photon Wannier-stark ladders (WSLs) and Zener tunneling (ZT) in one dimensional dual-periodical (DP) optical superlattices based on Porous Silicon (PSi), is presented. An introduction of linear gradient in physical thickness of the layers, composed of five stacks of two different periodic substructures, resulted in the appearance of four WSLs resonances and resonant Zener tunneling of nearest resonances of two consecutive WSLs. Theoretical analysis of time-resolved reflection spectra as a function of gradient reveals the presence of photonic Bloch oscillations (BOs) and an eventual tunneling at a specific value of linear gradient (20%), has been demonstrated through scattering maps. Measured reflection from different DP photonic structures confirm the presence of minibands, WSLs and ZT in the near infrared region.

[Interpretation of the pivot test using accelerometers in the orthopedic practice]. / Interpretación de la maniobra de pivote mediante el uso de acelerómetros en pacientes que acuden a consulta ortopédica.

The anterior (A) and posterior (P) cruciate ligaments (CL) of the knee, located inside the joint, connect the femur and the tibia and thus provide stability in the anteroposterior axis of one bone over the other. The anterior cruciate ligament (ACL) may be injured as a result of rotation when practicing a sport involving turning with the foot on the ground. ACL injuries are diagnosed with maneuvers like the Lachman, drawer and pivot. Accelerometers were used to plot the pivot maneuver in patients seeing the orthopedist surgeon using the KT1000 test as gold standard. This case-control descriptive study was approved by the Hospital's Ethics Committee. Results: 92 patients accepted to participate through an informed consent; nine cases were KT1000 positive, and nine age- and gender-matched controls were selected among KT1000 negative patients. KT1000 alterations were greater among females (78%) and in 67% of cases the right leg was affected. Mean KT1000 results were 5.44 mm in cases and 0.66 mm in controls. Accelerometers allowed plotting the pivot maneuver and the resulting charts for cases and controls were similar. Remarkable differences were seen only in one male patient with a 15 mm KT1000, who underwent repair of the left ACL; the maneuver was performed under sedation. We concluded that conscious patients oppose the maneuver, unlike anesthetized patients, and that the use of accelerometers helps document the pivot maneuver which, in turn, helps detect differences between a normal ACL and an injured one.

Combined metallothioneins and p53 proteins expression as a prognostic marker in patients with Dukes stage B and C colorectal cancer.

Our study aimed to evaluate metallothionein and p53 expression in colorectal cancer and to correlate their combined expression with selected clinical and pathologic variables of the disease, to define their prognostic significance. Colorectal cancer specimens from 99 patients were retrospectively analyzed by immunohistochemistry for metallothionein and p53 expression. Survival curves were generated according to the Kaplan-Meier method, and univariate survival distributions were compared with the use of the log-rank test. Multivariate models were computed using Cox proportional hazards regression. This research was approved by the institutional review boards of all centers. Tumors showing concomitant high metallothionein expression and negative p53 (metallothionein(H)/p53(-)) were significantly inversely related to depth of invasion, frequency of nodal metastasis, and Dukes stage (P < .01). In univariate analysis, patients with metallothionein(H)/p53(-) phenotype showed a better overall survival (hazard ratio [HR], 2.83; P < .05) and disease-free survival (HR, 2.03; P < .05). In multivariate analysis, considering staging, metallothionein, and metallothionein + p53 variables, in 83 patients with Dukes stages B and C, metallothionein(H)/p53(-) combination was the sole factor showing an independent prognostic value for overall survival (HR, 3.88; P < .1) and disease-free survival (HR, 2.56; P < .1). In conclusion, the combined analysis of metallothionein and p53 may enhance the prognostic power of each individual marker by predicting the progression of the disease and contributing to a better identification of patients at low risk for mortality, especially for those with Dukes stage B and C colorectal cancer.

IL-15 and IL-2 increase Cetuximab-mediated cellular cytotoxicity against triple negative breast cancer cell lines expressing EGFR.

Triple negative breast cancer (TNBC) patients are not likely to benefit from anti-estrogen or anti-HER2 therapy and this phenotype is associated with a more aggressive clinical course and worse clinical outcome. Taking into account the limited treatment possibilities in TNBC, the aim of the present work was to study a potential therapy based on Cetuximab-mediated immune activity by natural killer (NK) cells. We performed in vitro studies on human breast cancer (BC) cell lines, IIB-BR-G, and the in vivo metastatic variant IIB-BR-G MT. The immunohistochemical analysis showed a TNBC phenotype with high but different levels of EGFR expression on each cell line, measured by flow cytometry. DNA sequencing showed that both cell lines have a mutated K-RAS status, 38 G > A at codon 13. Consequently, Cetuximab did not inhibit cellular proliferation or induce apoptosis. We investigated if Cetuximab could trigger immune mechanisms, and we determined that both cell lines treated with 1 µg/ml Cetuximab were susceptible to antibody dependent cellular cytotoxicity (ADCC), mediated by peripheral blood mononuclear cells (PBMC). At 50:1 effector:target ratio, lytic activity was 34 ± 2% against IIB-BR-G and 27 ± 6% against IIB-BR-G MT cells. PBMC pretreatment with IL-2 allowed reaching 65 ± 3% of Cetuximab-mediated ADCC against IIB-BR-G and 63 ± 6.5% against IIB-BR-G MT. Furthermore, IL-15 pretreatment increased the ADCC up to 71 ± 3% in IIB-BR-G and 79 ± 3.5% in IIB-BR-G MT. We suggest that NK cells are the effectors present in PBMC since they were able to induce ADCC at lower effector:target ratios. Besides, IL-2- and mainly IL-15-induced upregulation of NK activating receptors CD16 and NKG2D and enhanced IFN-γ production. EGFR-expressing TNBC could be killed by Cetuximab-mediated ADCC at clinically achievable concentrations. IL-15 could advantageously replace IL-2 in most of its immunologic activities, stimulating the ability to produce IFN-γ, and paralleling the up-regulation of activating receptors.

Dolor abdominal en un paciente oncológico / Abdominal pain in oncology patient

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Análisis concepuual del aprendizaje observaciónal y la imitación a conceptual / Anlysis of obserrvational learning and imitation

Concepts presented to explain social learning, observational learning and imitation were analyzed. Hogan’s (1994) model for behavioral development was used to organize them and to show that those concepts refer to different sources of stimulus control, rather than to different processes. Valence change and potentiation were named as associative factors that determine observational learning. The relation between observational learning and occasion setting was underlined. It is suggested that these three terms are variants of the conditional discrimination paradigm.

En este trabajo se analizaron los conceptos que se han presentado para explicar lo que ocurre en situaciones de aprendizaje social, aprendizaje observacional e imitación. Con el uso del modelo de desarrollo del comportamiento presentado por Hogan (1994b) para organizarlos se señaló que los conceptos analizados se refieren a diferentes fuentes de control del estímulo. Se revisaron, asimismo, los factores asociativos que determinan tanto el aprendizaje social como el cambio de valencia y la potenciación; se indicó, también, la relación del aprendizaje social con la disposición de la ocasión. Se sugiere que estos tres términos equivalen a un paradigma de discriminación condicional.

Speed of sound in periodic elastic composites.

We consider the low-frequency limit (homogenization) for propagation of sound waves in periodic elastic medium (phononic crystals). Exact analytical formulas for the speed of sound propagating in a three-dimensional periodic arrangement of liquid and gas or in a two-dimensional arrangement of solids are derived. We apply our formulas to the well-known phenomenon of the drop of the speed of sound in mixtures. For air bubbles in water we obtain a perfect agreement with the recent results of coherent potential approximation obtained by Phys. Rev. Lett. 84, 6050 (2000)] if the filling of air bubbles is far from close packing. When air spheres almost touch each other, the approximation gives 10 times lower speed of sound than the exact theory does.

Personal exposure to benzene, toluene and xylene in different microenvironments at the Mexico City metropolitan zone.

The Mexico City Metropolitan Zone (ZMCM) population's exposure to benzene, toluene and xylene was measured at different microenvironments to establish basic indicators of the presence and effects of these characteristic volatile organic compounds (VOC). In particular, VOC personal exposures were measured in different microenvironments during a 5-day working week, with 12-h daily periods. We have found a good agreement of our results with the registered VOC levels of the Metropolitan Automated Monitor System (RAMA) for the corresponding period. From our results, we expect to generate useful information to evaluate the health effects of these VOCs on exposed people.

Atmospheric volatile organic compound measurements during the 1996 Paso del Norte Ozone Study.

Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US (El Paso) and Mexican (Ciudad Juárez) side of the border during a six-week period of the 1996 Paso del Norte Ozone Study. Samples were collected at five sites, three on the US side and two on the Mexican side, during nine intensive operation days when high ozone levels were forecast for the area. Six other sites were sampled to characterize up-wind, down-wind and other emission sources. Samples for determining source profiles were collected for rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuels, and industrial manufacturing in Cd. Juárez and a refinery in El Paso. Most samples were collected in electro-polished stainless steel canisters for determination of C2 to C(10+) hydrocarbons by GC-FID. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites during aircraft flights and analyzed by HPLC. This paper presents the spatial and temporal characteristics of VOC species concentrations and compositions to examine the differences and similarities of the various locations and time periods. Overall surface, total non-methane hydrocarbon values ranged from 0.1 to 3.4 ppmC with the highest concentrations being recorded in the morning and evening at five vehicle-dominated sites, three in Cd. Juárez and two in El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cd. Juárez, were the most abundant hydrocarbons. The most abundant carbonyls were acetaldehyde, acetone and formaldehyde.

Simultaneous generation of spectrally distinct third harmonics in a photonic crystal fiber.

By coupling femtosecond pulses at lambda - 1.55mum in a short length (Z - 95 cm) of photonic crystal fiber, we observe the simultaneous generation of two visible radiation components. Frequency-resolved optical gating experiments combined with analysis and modal simulations suggest that the mechanism for their generation is third-harmonic conversion of the fundamental pulse and its split Raman self-shifted component.