Photocatalytic behavior for the phenol degradation of ZnAl layered double hydroxide functionalized with SDS.

Functionalized ZnAl layered double hydroxide based photocatalyst was obtained by the addition of sodium dodecyl sulfate (SDS) during the synthesis by the coprecipitation method, and further calcination at 400 °C. Bare and modified materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, IR, UV-Vis, EPR and XPS spectroscopies, SEM and HRTEM. The synthesized material was evaluated in the photodegradation of phenol in a 40 ppm aqueous solution (4.25 × 10-4 mol of phenol/L), under UV light irradiation. An increasing in the degradation of phenol from 62 to 95%, and from 62 to 82% in the mineralization of phenol was obtained using SDS functionalized ZnAl LDH, in comparison with the unmodified material. This increase could be attributed to the presence of sulfate radicals, confirmed by the EPR study.

[Cutaneous myiasis due to Cochliomyia hominivorax associated with seborrheic dermatitis]. / Miasis cutánea por Cochliomyia hominivorax asociada a dermatitis seborreica: Case report.

Myiasis is an infestation of tissues and organs of humans and animals by Diptera larvae (flies, horseflies, mosquitoes). They are located at different body sites, and classified clinically as cutaneous, visceral and cavitary. We report a 26-year-old woman with a history of seborrheic dermatitis and recent trip to Brazil. She presented with a seven days history of suppurating wounds in the parieto-occipital area of the scalp. At physical examination we found three ulcers of approximately 1.5 cm each, with multiple mobile larvae inside. The obtained larvae were analyzed, identifying Cochliomyia hominivorax larvae at L2 and L3 stages. The patient was managed successfully with oral antimicrobials and local cleansing. The screwworm Cochliomyia hominivorax in our country is rare. Known risk factors are wounds, poor personal hygiene, extreme ages, psychiatric disorders, presence of specific dermatosis such as psoriasis and seborrheic dermatitis, among others.

Electrical conductivity of oxidized-graphenic nanoplatelets obtained from bamboo: effect of the oxygen content.

The large-scale production of graphene and reduced-graphene oxide (rGO) requires low-cost and eco-friendly synthesis methods. We employed a new, simple, cost-effective pyrolytic method to synthetize oxidized-graphenic nanoplatelets (OGNP) using bamboo pyroligneous acid (BPA) as a source. Thorough analyses via high-resolution transmission electron microscopy and electron energy-loss spectroscopy provides a complete structural and chemical description at the local scale of these samples. In particular, we found that at the highest carbonization temperature the OGNP-BPA are mainly in a sp(2) bonding configuration (sp(2) fraction of 87%). To determine the electrical properties of single nanoplatelets, these were contacted by Pt nanowires deposited through focused-ion-beam-induced deposition techniques. Increased conductivity by two orders of magnitude is observed as oxygen content decreases from 17% to 5%, reaching a value of 2.3 × 10(3) S m(-1) at the lowest oxygen content. Temperature-dependent conductivity reveals a semiconductor transport behavior, described by the Mott three-dimensional variable range hopping mechanism. From the localization length, we estimate a band-gap value of 0.22(2) eV for an oxygen content of 5%. This investigation demonstrates the great potential of the OGNP-BPA for technological applications, given that their structural and electrical behavior is similar to the highly reduced rGO sheets obtained by more sophisticated conventional synthesis methods.

Challenges of modelling real nanoparticles: Ni@Pt electrocatalysts for the oxygen reduction reaction.

Theoretical/computational methods have been extensively applied to screen possible nano-structures attempting to maximize catalytic and stability properties for applications in electrochemical devices. This work shows that the method used to model core@shell structures is of fundamental importance in order to truly represent the physicochemical changes arising from the formation of a core-shell structure. We demonstrate that using a slab approach for modelling nanoparticles the oxygen adsorption energies are qualitatively well represented. Although this is a good descriptor for the catalytic activity, huge differences are found for the calculated surface stability between the results of a nano-cluster and those of a slab approach. Moreover, for the slab method depending on the geometric properties of the core and their similarity to the elements of the core or shell, contradictory effects are obtained. In order to determine the changes occurring as the number of layers and nano particle size are increased, clusters of Ni@Pt from 13 to 260 atoms were constructed and analyzed in terms of geometric parameters, oxygen adsorption, and dissolution potential shift. It is shown that the results of modelling the Ni@Pt nanoparticles with a cluster approach are in good agreement with experimental geometrical parameters, catalytic activity, and stability of a carefully prepared series of Ni@Pt nanostructures where the shell thickness is systematically changed. The maximum catalytic activity and stability are found for a monolayer of Pt whereas adding a second and third layer the behavior is almost the same than that in pure Pt nanoparticles.

Near-Complete Genome Sequence of a SARS-CoV-2 VOC 202012/01 Strain in Peru.

A near-complete genome sequence was obtained for a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern (VOC) 202012/01 strain obtained from an oropharyngeal swab sample from a Peruvian patient with coronavirus syndrome who had contact with an individual who had recently returned from England.

Large changes in Pluto's atmosphere as revealed by recent stellar occultations.

Pluto's tenuous nitrogen atmosphere was first detected by the imprint left on the light curve of a star that was occulted by the planet in 1985 (ref. 1), and studied more extensively during a second occultation event in 1988 (refs 2-6). These events are, however, quite rare and Pluto's atmosphere remains poorly understood, as in particular the planet has not yet been visited by a spacecraft. Here we report data from the first occultations by Pluto since 1988. We find that, during the intervening 14 years, there seems to have been a doubling of the atmospheric pressure, a probable seasonal effect on Pluto.

3-D reconstruction of the atomic positions in a simulated gold nanocrystal based on discrete tomography: prospects of atomic resolution electron tomography.

A novel reconstruction procedure is proposed to achieve atomic resolution in electron tomography. The method exploits the fact that crystals are discrete assemblies of atoms (atomicity). This constraint enables us to obtain a three-dimensional (3-D) reconstruction of test structures from less than 10 projections even in the presence of noise and defects. Phase contrast transmission electron microscopy (TEM) images of a gold nanocrystal were simulated in six different zone axes. The discrete number of atoms in every column is determined by application of the channelling theory to reconstructed electron exit waves. The procedure is experimentally validated by experiments with gold samples. Our results show that discrete tomography recovers the shape of the particle as well as the position of its 309 atoms from only three projections. Experiments on a nanocrystal that contains several missing atoms, both on the surface and in the core of the nanocrystal, while considering a high noise level in each simulated image were performed to prove the stability of the approach to reconstruct defects. The algorithm is well capable of handling structural defects in a highly noisy environment, even if this causes atom count "errors" in the projection data.

Teledermatología sincrónica en tiempos de Covid-19. Percepción del dermatólogo / Synchronous teledermatology in times of Covid-19. Dermatologist perception

Teledermatology (TD) is a remote medical care tool that experienced a great boom during the COVID19 pandemic, resulting in an increase in both, the number of remote consultations and the number of dermatologists who practice it. Several studies have reported a high degree of satisfaction among patients attended by this method. However, few studies have done so in dermatologists. We set out to investigate the experience of Chilean dermatologists with the tool by means of an online survey. Results. A total of 156 surveys were completed. The number of dermatologists using TD increased from 19.9% to 80.8% during the pandemic. They cited the absence of the physical examination-dermatoscopy as the main limitation to developing TD and reported feeling more comfortable with some pathologies. Dermatologists feel moderately comfortable and confident with the tool, however, they experienced varying degrees of stress and frustration. Only 40.8% plan to continue using TD in the future. Conclusion. Synchronous TD has clear limitations, however, these should emerge as an opportunity to consider in its development and its platforms, in order to generate a more comfortable tool for more dermatologists and thus extend its use, as an important tool for equal access to health care in Chile. (AU)

Phonon fingerprints of CsPb2Br5.

CsPb2Br5 is a stable, water-resistant, material derived from CsPbBr3 perovskite and featuring two-dimensional Pb-Br framework separated by Cs layers. Both compounds can coexist at nanolength scale, which often produces conflicting optical spectroscopy results. We present a complete set of polarized Raman spectra of nonluminescent CsPb2Br5 single crystals that reveals the symmetry and frequency of nondegenerate Raman active phonons accessible from the basal (0 0 1) plane. The experimental results are in good agreement with density functional perturbation theory simulations, which suggests that the calculated frequencies of yet unobserved double degenerate Raman and infrared phonons are also reliable. Unlike CsPbBr3, the lattice dynamics of CsPb2Br5 is stable as evidenced by the calculated phonon dispersion. The sharp Raman lines and lack of a dynamic-disorder-induced central peak in the spectra at room temperature indicate that the coupling of Cs anharmonic motion to Br atoms, known to cause the dynamic disorder in CsPbBr3, is absent in CsPb2Br5.

[Neurotrophic action of insulin-like growth factor-I in the inner ear]. / Acciones neurotróficas del factor de crecimiento similar a la insulina de tipo I en el oído interno.

INTRODUCTION: Loss of hearing constitutes one of the most frequent disabling sensory impairments in the developed world. Different therapeutic approaches are currently being studied, including treatment with stem cells, genetic manipulation and pharmacological protection. AIM: To evaluate the role played by insulin-like growth factor-I (IGF-I) in the development, maintenance and repair of auditory functioning. DEVELOPMENT: Proper development of the inner ear is dependent on a suitable coordination of the cell processes of proliferation, differentiation, neurogenesis and programmed cell death, which are regulated by different factors, one of which is IGF-I. During the embryogenesis of the inner ear, this factor is expressed in abundance and is essential for cell survival and maintaining neuronal precursors. Studies conducted in Igf-1-/- null mice have highlighted its importance in the development and continued functioning of the inner ear. Mice with a deficit in this gene display morphological disorders that correspond to severe functional deficiencies, which are confirmed by analysing brainstem auditory evoked potentials. A deficit of IGF-I in humans is also accompanied by profound sensory hypoacusis. CONCLUSIONS: In a scenario like this, IGF-I appears as a key factor in the development of auditory functioning and a candidate for regenerative therapy of the inner ear.

HRTEM low dose: the unfold of the morphed graphene, from amorphous carbon to morphed graphenes.

We present experimental evidence under low-dose conditions transmission electron microscopy for the unfolding of the evolving changes in carbon soot during mechanical milling. The milled soot shows evolving changes as a function of the milling severity or time. Those changes are responsible for the transformation from amorphous carbon to graphenes, graphitic carbon, and highly ordered structures such as morphed graphenes, namely Rh6 and Rh6-II. The morphed graphenes are corrugated layers of carbon with cross-linked covalently nature and sp2- or sp3-type allotropes. Electron microscopy and numerical simulations are excellent complementary tools to identify those phases. Furthermore, the TEAM 05 microscope is an outstanding tool to resolve the microstructure and prevent any damage to the sample. Other characterization techniques such as XRD, Raman, and XPS fade to convey a true identification of those phases because the samples are usually blends or mixes of the mentioned phases.

Adenovirus coxsackie adenovirus receptor-mediated binding to human erythrocytes does not preclude systemic transduction.

There is great skepticism in the capability of adenovirus vectors and oncolytic adenoviruses to reach specific organs or tumors upon systemic administration. Besides antibodies, the presence of CAR (coxsackie and adenovirus receptor) in human erythrocytes has been postulated to sequester CAR-binding adenoviruses, commonly used in gene therapy and oncolytic applications. The use of non-CAR-binding fibers or serotypes has been postulated to solve this limitation. Given the lack of integrins in erythrocytes and therefore of internalization of the CAR-bound virus, we hypothesized that the interaction of adenovirus type 5 (Ad5) with CAR in human erythrocytes could be reversible. In this work, we have studied the effects of Ad5 interaction with human erythrocytes via CAR. Although erythrocyte binding was observed, it did not reduce viral transduction of tumor cells in vitro after long-term incubations. Transplantation of human erythrocytes into nude mice did not reduce Ad5 extravasation and transduction of liver and human xenograft tumors after systemic administration. These findings indicate that despite human erythrocytes are able to bind to Ad5, this binding is reversible and does not prevent extravasation and organ transduction after systemic delivery. Thus, the poor bioavailability of systemically delivered CAR-binding adenoviruses in humans is likely due to other factors such as liver sequestration or neutralizing antibodies.

From the Worm in a Bottle of Mezcal: iDNA Confirmation of a Leech Parasitizing the Antillean Manatee.

Invertebrate-derived ingested DNA (iDNA) is quickly proving to be a valuable, non-invasive tool for monitoring vertebrate species of conservation concern. Using the DNA barcoding locus, we successfully identified both the blood-feeding leech Haementeria acuecueyetzin and its blood meal-the latter is shown to be derived from the Caribbean manatee, Trichechus manatus . DNA amplification was successful despite the fact that the specimen was fixed in Mezcal (a beverage distilled from agave). We report the first confirmed case of a leech feeding on a manatee, the first record of H. acuecueyetzin for the State of Chiapas and, to our knowledge, the first case of successful DNA amplification of a biological sample fixed in Mezcal other than the caterpillar "worms" more commonly found in that beverage.

Maintaining the genuine structure of 2D materials and catalytic nanoparticles at atomic resolution.

The recent development of atomic resolution, low dose-rate electron microscopy allows investigating 2D materials as well as catalytic nano particles without compromising their structural integrity. For graphene and a variety of nanoparticle compositions, it is shown that a critical dose rate exists of <100 e(-)/Å(2) s at 80 keV of electron acceleration that allows maintaining the genuine object structures including their surfaces and edges even if particles are only 3 nm large or smaller. Moreover, it is demonstrated that electron beam-induced phonon excitation from outside the field of view contributes to a contrast degradation in recorded images. These degradation effects can be eliminated by delivering electrons onto the imaged area, only, by using a Nilsonian illumination scheme in combination with a suitable aperture at the electron gun/monochromator assembly.

Instrumental requirements for the detection of electron beam-induced object excitations at the single atom level in high-resolution transmission electron microscopy.

This contribution touches on essential requirements for instrument stability and resolution that allows operating advanced electron microscopes at the edge to technological capabilities. They enable the detection of single atoms and their dynamic behavior on a length scale of picometers in real time. It is understood that the observed atom dynamic is intimately linked to the relaxation and thermalization of electron beam-induced sample excitation. Resulting contrast fluctuations are beam current dependent and largely contribute to a contrast mismatch between experiments and theory if not considered. If explored, they open the possibility to study functional behavior of nanocrystals and single molecules at the atomic level in real time.

Hamartoma fibroso de la infancia: reporte de caso / Fibrous hamartoma of infancy: a case report

Resumen: El hamartoma fibroso de la infancia (FHI) es una lesión rara de tejidos blandos en niños con morfología trifásica característica. El principal problema con estas lesiones es el diagnóstico diferencial con otras masas de tejidos blandos, en particular sarcomas, que requieren un afrontamiento clínico y terapéutico diferente. Presentamos un caso de un infante de 10 meses con un crecimiento asintomático de una masa axilar que, tras realizarse angioresonancia magnética y biopsia se confirmó el diagnóstico de FHI.

Abstract: Fibrous hamartomas of childhood (FHC) are rare soft tissue lesions in infants and young children with characteristic three-phase morphology.The main problem with these lesions is differentiating it from other soft tissue masses, in particular sarcomas, which require a different clinical and therapeutic approach. We present a case of a 10-month-old infant with asymptomatic growth of a left axillary mass that, after magnetic resonance angiography and biopsy, the diagnosis of FHC was confirmed.

Coledococele: caso diagnosticado por resonancia magnética / Choledococele: case diagnosed by MRI

Resumen: El coledococele es una dilatación quística del segmento distal del conducto biliar común que sobresale en el lumen duodenal. Estos comprenden menos del 2% de todos los casos reportados de quistes de colédoco (2). Los hallazgos imagenológicos del coledococele y de los quistes de duplicación duodenal son muy similares, ambos presentan además clínica variada e inespecífica, por lo que el diagnóstico definitivo suele ser durante la cirugía. Presentamos un caso de una paciente de 10 años que consulta por dolor abdominal con elevación de transaminasas que, tras estudio con resonancia magnética con colangioresonancia y EDA se diagnostica coledococele.

Abstract: Choledochocele is a cystic dilation of the distal segment of the common bile duct protruding into the duodenal lumen. Is also known as type III choledochal cyst according to Todani's classification. It is usually misdiagnosed as duodenal duplication cyst. Multislice spiral computed tomography and magnetic resonance cholangiopancreatography may be comparable to endoscopic retrograde cholangiography for diagnosis of choledochocele. We present a case of a 10-years-old girl presented with abdominal pain, elevation of transaminases and a magnetic resonance cholangiopancreatography (MRCP) scan that revealed a choledochocele.

Efficacy of hepatobiliary imaging of acute abdominal pain: concise communication.

To assess prospectively the usefullness of hepatobiliary imaging in acute abdominal pain (72 hr or less), 36 patients were scintigraphed after intravenous injection of 5 mCi of Tc-99m p-isopropyl-iminodiacetic acid (PIPIDA). Before the procedure, the referring physician completed Part I of a questionnaire indicating his differential diagnosis, diagnostic confidence (expressed as a percentage), and therapeutic plan. Immediately after the test, the same physician, with knowledge of the results, completed Part II of the questionnaire indicating again his differential diagnosis, diagnostic confidence, and therapeutic plan. The impact of the imaging on the physician's diagnositic confidence was expressed as a log-likelihood-ratio (LLR). The mean LLR for this series was 1.48 +/- 0.93, with 33 of 36 (92%) patients demonstrating a LLR greater than 0.0. In 26 of 33 patients, a LLR greater than 1.0 was achieved; and in 11 of 36 patients, a change in the physician's therapeutic plan occurred, reflecting the considerable impact of hepatobiliary imaging on the decision-making process.