An autonomous power temperature sensor based on window-integrated transparent PV using sustainable luminescent carbon dots.

The energy efficiency of buildings can be significantly improved through the use of renewable energy sources. Luminescent solar concentrators (LSCs) appear to be a solution for integrating photovoltaic (PV) devices into the structure of buildings (windows, for instance) to enable low-voltage devices to be powered. Here, we present transparent planar and cylindrical LSCs based on carbon dots in an aqueous solution and dispersed in organic-inorganic hybrid matrices, which present photoluminescent quantum yield values up to 82%, facilitating an effective solar photon conversion. These LSCs showed the potencial for being incorporated as building windows due to an average light transmittance of up to ∼91% and color rendering index of up to 97, with optical and power conversion efficiency values of 5.4 ± 0.1% and 0.18 ± 0.01%, respectively. In addition, the fabricated devices showed temperature sensing ability enabling the fabrication of an autonomous power mobile temperature sensor. Two independent thermometric parameters were established based on the emission and the electrical power generated by the LSC-PV system, which could both be accessed by a mobile phone, enabling mobile optical sensing through multiparametric thermal reading with relative sensitivity values up to 1.0% °C-1, making real-time mobile temperature sensing accessible to all users.

SAFETY AND EFFICACY OF THYMIC PEPTIDES IN THE TREATMENT OF HOSPITALIZED COVID-19 PATIENTS IN HONDURAS.

Coronavirus disease 2019 (Covid-19) active cases continue to demand the development of safe and effective treatments. This is the first clinical trial to evaluate the safety and efficacy of oral thymic peptides. ; We conducted a nonrandomized phase 2 trial with a historic control group to evaluate the safety and efficacy of a daily 250-mg oral dose of thymic peptides in the treatment of hospitalized Covid-19 patients. Comparisons based on standard care from registry data were performed after propensity score matching. The primary outcomes were survival, time to recovery, and number of participants with treatment-related adverse events or side effects by day 20. ; A total of 44 patients were analyzed in this study: 22 in the thymic peptide group and 22 in the standard care group. There were no deaths in the intervention group compared to 24% mortality in standard care by day 20 (log-rank P=0.02). Kaplan-Meier analysis showed a significantly shorter time to recovery by day 20 in the thymic peptide group than in the standard care group (median, 6 days vs. 12 days; hazard ratio for recovery, 2.75 [95% confidence interval, 1.34 to 5.62]; log-rank P=0.002). No side effects or adverse events were reported. ; In patients hospitalized with Covid-19, the use of thymic peptides resulted in no side effects, adverse events, or deaths by day 20. Compared with the registry data, a significantly shorter time to recovery and mortality reduction were measured.

[Pathogenic mechanisms of SARS-CoV-2 infection and kidney disease: a clinical and molecular perspective].

The SARS-CoV-2 infection has become as a worldwide public health emergency. It exhibits a variety of clinical presentations, ranging from benign to acute respiratory distress syndrome, systemic involvement, and multiorganic failure. The severity of the clinical picture depends on host and virus biological features and the presence of comorbidities such as chronic kidney disease. In addition, the interaction between the virus, angiotensin-converting enzyme 2, and the exacerbated immune response could lead to the development of acute kidney injury. However, the implications of SARS-CoV-2 infection on renal cells, the prognosis of patients with chronic kidney disease, and the long-term behavior of renal function are not entirely understood. This review aims to explore the role of SARS-CoV-2 in acute and chronic kidney disease and the possible pathogenic mechanisms of renal involvement.

The Surfaces of the Ceratonia siliqua L. (Carob) Leaflet: Insights from Physics and Chemistry.

The production of superhydrophobic coatings inspired by the surface of plant leaves is a challenging goal. Such coatings hold a bright technological future in niche markets of the aeronautical, space, naval, building, automobile, and biomedical sectors. This work is focused on the adaxial (top) and abaxial (bottom) surfaces of the leaflet of the Ceratonia silique L. (carob), a high-commercial-value Mediterranean tree cultivated in many regions of the world. The adaxial and abaxial surfaces feature hydrophobic and superhydrophobic behaviors, respectively. Their chemical composition is very simple: monopalmitin ester and palmitic acid are protuberant in the epicuticular and intracuticular wax layers of the adaxial surface, respectively, whereas 1-octacosanol dominates in the abaxial wax layers. In both surfaces, epicuticular wax is organized along a randomly oriented and intricate network of nanometer-thick and micrometer-long plates, whose density and degree of interconnection are significantly higher in the abaxial surface. The measured tilting angles for the abaxial surface (12-70°) reveal unusual variable density and water adhesion of the nanostructured plate-based texture. Optical measurements demonstrate that light reflectance/absorbance of the glaucous abaxial surface is significantly higher/lower than that of the nonglaucous adaxial surface. In both surfaces, diffuse reflectance is dominant, and the absorbance is weakly dependent on the light incidence angle. We show that the highly dense nanostructured platelike texture of the epicuticular abaxial layer of the C. siliqua leaflet works as a sophisticated light and water management system: it reflects solar radiation diffusely to lower the surface temperature, and it has superhydrophobic character to keep the surface dry. Such attributes enable efficient gas exchange (photosynthesis and respiration), transpiration, and evaporation. To mimic for the first time the abaxial surface, a templation approach was adopted using poly(dimethylsiloxane) (PDMS)/poly(methylphenylsiloxane) (PMPS) positive/negative replicas and a soft polymer/siloxane negative replica produced by the sol-gel process. Because high topographical variations of the biotemplate and wax adhesion to the biohybrid film affected the replication quality, the reproduction of the wax texture via the synthesis of 1-octacosanol-grafted siloxane-based hybrid materials is proposed as a suitable route to duplicate the abaxial surface with high fidelity. The natural chemical/physical strategy adopted by the C. siliqua leaflet to face the harsh Mediterranean climate is a powerful source of bioinspiration for the development of diffuse reflecting and superhydrophobic material systems with foreseen applications as dual-functional antiglare and water-repelling coatings.

Enhanced ionic conductivity in poly(vinylidene fluoride) electrospun separator membranes blended with different ionic liquids for lithium ion batteries.

Electrospun poly(vinylidene fluoride) (PVDF) fiber membranes doped with different ionic liquids (ILs) and sharing the same anion were produced and their potential as separator membranes for battery applications was evaluated. Different types of ILs containing the same anion, bis(trifluoromethylsulfonyl)imide [TFSI]-, were used with IL concentrations ranging between 0 and 15 wt% The morphology, microstructure, thermal and electrical properties (ionic conductivity and electrochemical window) of the membranes were evaluated. The presence of ILs in the PVDF polymer matrix influences the fiber diameter and the content of the polar ß phase within the polymer, as well as the degree of crystallinity. The thermal stability of the membranes decreases with the incorporation of IL. Impedance spectroscopy tests show a maximum ionic conductivity of 2.8 mS.cm-1 for 15% of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) at room temperature. The electrochemical stability of the samples ranges from 0.0 to 6.0 V. When evaluated as battery separator membranes in C-LiFePO4 half-cells, a maximum discharge capacity of 119 mAh.g-1 at C-rate was obtained for the PVDF membrane with 15% [Emim][TFSI], with a coulombic efficiency close to 100%. The results demonstrate that the produced electrospun membranes are suitable for applications as separators for lithium ion batteries (LIBs).

Luminescent κ-Carrageenan-Based Electrolytes Containing Neodymium Triflate.

In recent years, the synthesis of polymer electrolyte systems derived from biopolymers for the development of sustainable green electrochemical devices has attracted great attention. Here electrolytes based on the red seaweeds-derived polysaccharide κ-carrageenan (κ-Cg) doped with neodymium triflate (NdTrif3) and glycerol (Gly) were obtained by means of a simple, clean, fast, and low-cost procedure. The aim was to produce near-infrared (NIR)-emitting materials with improved thermal and mechanical properties, and enhanced ionic conductivity. Cg has a particular interest, due to the fact that it is a renewable, cost-effective natural polymer and has the ability of gelling in the presence of certain alkali- and alkaline-earth metal cations, being good candidates as host matrices for accommodating guest cations. The as-synthesised κ-Cg-based membranes are semi-crystalline, reveal essentially a homogeneous texture, and exhibit ionic conductivity values 1⁻2 orders of magnitude higher than those of the κ-Cg matrix. A maximum ionic conductivity was achieved for 50 wt.% Gly/κ-Cg and 20 wt.% NdTrif3/κ-Cg (1.03 × 10-4, 3.03 × 10-4, and 1.69 × 10-4 S cm-1 at 30, 60, and 97 °C, respectively). The NdTrif-based κ-Cg membranes are multi-wavelength emitters from the ultraviolet (UV)/visible to the NIR regions, due to the κ-Cg intrinsic emission and to Nd3+, 4F3/2→4I11/2-9/2.

Structuring of Amide Cross-Linked Non-Bridged and Bridged Alkyl-Based Silsesquioxanes.

The development of sophisticated organized materials exhibiting enhanced properties is a challenging topic of the domain of organic/inorganic hybrid materials. This review, composed of four sections, reports the work we have carried out over the last 10 years on the synthesis of amide cross-linked alkyl/siloxane hybrids by means of sol-gel chemistry and self-directed assembly/self-organization routes relying on weak interactions (hydrophobic interactions and hydrogen bonding). The various as-produced lamellar structures displaying a myriad of morphologies, often closely resembling those found in natural materials, are discussed. The major role played by the synthetic conditions (pH, water content, co-solvent(s) nature/concentration and dopant presence/concentration), the alkyl chains (length and presence of ramification or not) and the number of the amide cross-links present in the precursor, is evidenced. Examples of highly organized hybrids structures incorporating ionic species (alkali and alkaline earth metal salts) and optically-active centers (organic dyes and lanthanide ions) are described. A useful qualitative relationship deduced between the emission quantum yield of the ordered hybrid materials and the degree of order of the hydrogen-bonded network is highlighted.

Fabrication of low-cost thermo-optic variable wave plate based on waveguides patterned on di-ureasil hybrids.

An integrated variable wave plate device based on a thermo-optic (TO) effect was fabricated by patterning a waveguide channel through direct UV laser writing on the surface of sol-gel derived organic-inorganic hybrid (di-ureasil) films. The di-ureasil layer is stable up to 250 °C and has a high TO coefficient calculated as -(4.9 ± 0.5) × 10(-4) °C(-1) at 1550 nm. The waveguide temperature was tuned, inducing optical phase retardation between the transverse electric and transverse magnetic modes, resulting in a controllable wave plate. A maximum phase retardation of 77 ° was achieved for a waveguide induced temperature increase of 5 °C above room temperature, with a power consumption of 0.4 W. The thermal linear retardation coefficient was calculated to be 19 ± 1 °/ °C.

Design and construction of a research atomic layer deposition system for in situ infrared and electron spectroscopies.

A description is given of an ultra-high vacuum surface-analysis chamber that incorporates an internal cell for performing atomic layer deposition at a pressure of up to ∼1 Torr. The apparatus permits the growth process to be interrupted in stages during which data can be obtained using infrared and x-ray photoemission spectroscopies together with other electron-based techniques. Demonstration results are given for the adsorption of H2O on Si (100) at a pressure of ∼0.3 Torr. The system described is generally applicable in the study of any surface reaction under non-high-vacuum conditions in which there is a need for both infrared and electron spectroscopies.

Luminescent DNA- and agar-based membranes.

Luminescent materials containing europium ions are investigated for different optical applications. They can be obtained using bio-macromolecules, which are promising alternatives to synthetic polymers based on the decreasing oil resources. This paper describes studies of the DNA- and Agar-europium triflate luminescent membranes and its potential technological applications are expanded to electroluminescent devices. Polarized optical microscopy demonstrated that the samples are birefringent with submicrometer anisotropy. The X-ray diffraction analysis revealed predominantly amorphous nature of the samples and the atomic force microscopy images showed a roughness of the membranes of 409.0 and 136.1 nm for the samples of DNA10Eu and Agar1.11Eu, respectively. The electron paramagnetic resonance spectra of the DNA(n)Eu membranes with the principal lines at g ≈ 2.0 and g ≈ 4.8 confirmed uniform distribution of rare earth ions in a disordered matrix. Moreover, these strong and narrow resonance lines for the samples of DNA(n)Eu when compared to the Agar(n)Eu suggested a presence of paramagnetic radicals arising from the DNA matrix. The emission spectra suggested that the Eu3+ ions occupy a single local environment in both matrices and the excitation spectra monitored around the Eu emission lines pointed out that the Eu3+ ions in the Agar host were mainly excited via the broad band component rather than by direct intra-4f(6) excitation, whereas the opposite case occurred for the DNA-based sample.

Investigation of the interaction of γ-Al2O3 with aqueous solutions of dimethyl methylphosphonate using infrared multiple internal reflection spectroscopy.

The interaction of dilute solutions of dimethyl methylphosphonate (DMMP) in H(2)O with thin porous layers of γ-Al(2)O(3) has been studied under steady-state conditions using infrared multiple-internal-reflection spectroscopy. Upon the initial introduction of the DMMP solution to a previously H(2)O-saturated surface, DMMP diffuses into the porous layer and displaces weakly hydrogen-bonded H(2)O molecules. This is accompanied by hydrolysis of the γ-Al(2)O(3) to form Al(OH)(3) and/or AlO(OH). The P═O group of DMMP interacts predominantly with H(2)O and gives no clear indication of bonding to the oxide surface itself, from which it is inferred that the displacement of weakly adsorbed H(2)O results from the interaction of acidic Al-OH sites with the methoxy O atoms of DMMP. No hydrolysis of the DMMP, either in solution or in contact with the oxide, was detectable under the present conditions. The results have practical implications in the decontamination of materials following exposure to toxic reagents related to DMMP.

Effect of clonidine in mice injected with Tityus discrepans scorpion venom.

A study was conducted to assess the effect of clonidine (α(2)-adrenoceptor selective agonist) on glycemia, serum and urine α-amylase, blood urea nitrogen (BUN), serum creatinine, white blood cell count, kidney histology and zymogen granule content in pancreatic acini, in mice under the effect of Tityus discrepans (Td) scorpion venom. BALB/c male mice (20 ± 2 g, n = 7-11) were intraperitoneally (ip) injected with a sublethal dose (1 µg/g) of Td venom, and were treated (ip) with 0.1 µg/g of clonidine (Catapresan(®)) or 0.9% NaCl 30 min after the venom injection, and then every 2 h. Six hours later, mice were anesthetized with diethylether and urine and blood samples were withdrawn by cystocentesis and cardiocentesis, respectively. Tissue samples were obtained and fixed immediately in buffered formalin (2%, pH 7.4) and then processed for stain H&E. Td venom did not cause hyperglycemia by itself. However, clonidine induced hyperglycemia, which was synergized by Td venom. Although the venom did not produce hyperamylasemia, clonidine significantly diminished serum α-amylase activity in envenomed mice. Td venom did not significantly increase urinary α-amylase activity, which was unaffected by clonidine. Morphometric analysis using microphotographs of pancreata from mice injected with Td venom showed a reduced zymogen granule content as judged by the acidophilic bidimensional area of acini. This effect was significantly reduced by clonidine. Kidney samples showed histological changes which were partially affected by the drug. Clonidine reduced the increase in BUN and serum creatinine concentration in envenomed mice. Td venom produced neutrophilia and lymphopenia, which were clonidine-resistant at the assayed dose. These results suggest that α(2)-adrenoceptor selective agonists would be able to reduce some scorpion venom-induced renal and pancreatic disturbances, possibly through the inhibition of neurotransmitter release from presynaptic cholinergic and noradrenergic terminals, as well as from adrenal medulla.

Espectro clínico de la hepatotoxicidad por nitrofurantoína en serie clínica de 12 pacientes / Clinical spectrum of nitrofurantoin hepatotoxicity in a series of 12 patients

Nitrofurantoin, commonly used for prolonged periods, can produce different patterns of liver damage. Patients: 12 women, mean age 55 years (range 17-72), with recurrent urinary infections, treated with nitrofurantoin for long periods of time (2 months to 15 years), who presented with secondary liver disease. Results: 7 had acute hepatitis (3 fulminant), 3 chronic hepatitis, and 2 cirrhosis. All acute cases had consistent liver biopsies, and 2 were treated with steroids and azathioprine for 2 and 7 months, with liver tests normalization. Two fulminant cases were transplanted (submassive hepatic necrosis on explanted livers) and 1 was successfully treated with steroids and mycofenolate. The 3 cases of chronic hepatitis also had confirmatory biopsies and 1 received steroids and azathioprine, with full recovery. The other 2 responded to the drug withdrawal and the 2 cirrhotic patients had only symptomatic treatment. All patients were negative for hepatitis virus, 7 (58 percent had positive anti-nuclear and/or anti-smooth muscle antibodies and 4 (33 percent) had elevated IgG levels. Conclusions: Nitrofurantoin may cause severe acute liver disease, even requiring liver transplantation. Nitrofurantoin can also cause chronic liver disease, have markers of autoimmunity and respond to immunosuppressive therapy. These data confirmed that nitrofurantoin can induce liver diseases, probably due to immunological mechanisms.

La nitrofurantoína, comúnmente utilizada por períodos prolongados, puede producir daño hepático, con diferentes formas de presentación y evolución. Pacientes: 12 mujeres, edad promedio 55 años (rango 17 a 72), con infecciones urinarias recurrentes, usuarias de nitrofurantoína por períodos prolongados (2 meses a 15 años), que presentaron daño hepático asociado a la droga. Resultados: 7 casos de hepatitis aguda (3 fulminantes), 3 casos de hepatitis crónica y 2 casos de cirrosis. Todos los casos de hepatitis agudas tenían biopsia hepática compatible y 2 fueron tratadas con corticoides y azatioprina por 2 y 7 meses, con normalización de los exámenes. De las 3 pacientes con hepatitis fulminante, 2 fueron trasplantadas (necrosis submasiva en el hígado explantado) y 1 fue tratada con corticoides y micofenolato, con buena respuesta. Los 3 casos de hepatitis crónica tenían confirmación histológica y 1 se trató con corticoides y azatioprina, con excelente evolución. Las otras pacientes respondieron favorablemente sólo a la suspensión del fármaco. Los 2 casos con cirrosis han recibido tratamiento sintomático. Todas las pacientes fueron negativas para los virus hepatitis, 7/12 (58 por ciento) tenían anticuerpos antinucleares y/o antimúsculo liso positivos y 4/12 (33 por ciento) IgG elevada. Conclusión: La nitrofurantoína puede provocar una severa enfermedad hepática aguda, requiriendo incluso trasplante hepático. Además, puede producir hepatitis crónica y cirrosis, tener marcadores de autoinmunidad y buena respuesta a la terapia inmunosupresora habitual. Lo anterior confirma su capacidad de inducir un daño hepático, probablemente por mecanismos inmunológicos.

Effects of molecular adsorption on the electronic structure of single-layer graphene.

The interaction of small molecules (CCl(4), CS(2), H(2)O, and acetone) with single-layer graphene (SLG) has been studied under steady-state conditions using infrared multiple-internal-reflection spectroscopy. Adsorption results in a broad and intense absorption band, spanning the ∼200 to 500 meV range, which is attributed to electronic excitation. This effect, which has not previously been reported for SLG, has been further investigated using dispersion-corrected density functional theory to model the adsorption of H(2)O on SLG supported on an SiO(2) substrate. However, the ideal and defect-free model does not reproduce the observed adsorption-induced electronic transition. This and other observations suggest that the effect is extrinsic, possibly the result of an adsorption-induced change in the in-plane strain, with important differences arising between species that form liquid-like layers under steady-state conditions and those that do not. Furthermore, the C-H stretching modes of CH(2) groups, incorporated in the SLG as defects, undergo nonadiabatic coupling to the electronic transition. This leads to pronounced antiresonance effects in the line shapes, which are analyzed quantitatively. These results are useful in understanding environmental effects on graphene electronic structure and in demonstrating the use of the vibrational spectroscopy of H-containing defects in characterizing SLG structure.

Li(+)- and Eu(³+)-doped poly(ε-caprolactone)/siloxane biohybrid electrolytes for electrochromic devices.

The sol-gel process has been successfully combined with the "mixed cation" effect to produce novel luminescent and ion conducting biohybrids composed of a diurethane cross-linked poly(ε-caprolactone) (PCL530)/siloxane hybrid network (PCL stands for the poly(ε-caprolactone) biopolymer and 530 is the average molecular weight in gmol(-1)) doped with a wide range of concentrations of lithium and europium triflates (LiCF(3)SO(3) and Eu(CF(3)SO(3))(3), respectively) (molar ratio of ca. 50:50). The hybrid samples are all semicrystalline: whereas at n = 52.6 and 27.0 (n, composition, corresponds to the number of (C(═O)(CH(2))(5)O) repeat units of PCL(530) per mixture of Li(+) and Eu(3+) ions) a minor proportion of crystalline PCL(530) chains is present, at n = 6.1, a new crystalline phase emerges. The latter electrolyte is thermally stable up to 220 °C and exhibits the highest conductivity over the entire range of temperatures studied (3.7 × 10(-7) and 1.71 × 10(-4) S cm(-1) at 20 and 102 °C, respectively). According to infrared spectroscopic data, major modifications occur in terms of hydrogen bonding interactions at this composition. The electrochemical stability domain of the biohybrid sample with n = 27 spans more than 7 V versus Li/Li(+). This sample is a room temperature white light emitter. Its emission color can be easily tuned across the Commission Internationale d'Éclairage (CIE) chromaticity diagram upon simply changing the excitation wavelength. Preliminary tests performed with a prototype electrochromic device (ECD) comprising the sample with n = 6.1 as electrolyte and WO(3) as cathodically coloring layer are extremely encouraging. The device exhibits switching time around 50 s, an optical density change of 0.15, good open circuit memory under atmospheric conditions (ca. 1 month) and high coloration efficiency (577 cm(2) C(-1) in the second cycle).

Effect of humidity on the interaction of dimethyl methylphosphonate (DMMP) vapor with SiO2 and Al2O3 surfaces, studied using infrared attenuated total reflection spectroscopy.

Infrared attenuated total reflection spectroscopy has been used to study the interaction of DMMP vapor with SiO(2), Al(2)O(3), and AlO(OH) vs relative humidity (RH) and DMMP partial pressure (P/P(0)). For SiO(2) the growth with increasing RH of ice-like and liquid-like layers is seen in agreement with previous work. H↔D exchange during exposure to H(2)O and D(2)O indicates that the ice-like layer is more resistant to exchange, consistent with stronger H-bonding than in the liquid-like layer. Exposure of nominally dry SiO(2) to D(2)O indicates the existence of adsorbed H(2)O that does not exhibit an ice-like spectrum. The ice-like layer appears only at a finite RH. Exposure of SiO(2) to DMMP in the absence of intentionally added H(2)O shows the formation of a strongly bound molecular species followed by a liquid-like layer. The strong interaction involves SiO-H···O═P bonds to surface silanols and/or HO-H···O═P bonds to preadsorbed molecular H(2)O. At a finite RH the ice-like layer forms on SiO(2) even in the presence of DMMP up to P/P(0) = 0.30. DMMP does not appear to penetrate the ice-like layer under these conditions, and the tendency to form a such a layer drives the displacement of DMMP. Amorphous Al(2)O(3) and AlO(OH) do not exhibit an ice-like H(2)O layer. Both have a higher surface OH content than does SiO(2), which leads to higher coverages of H(2)O or DMMP at equivalent RH or P/P(0). At low P/P(0), for which adsorption is dominated by Al-OH···O═P bonding, a-Al(2)O(3) interacts with DMMP more strongly than does AlO(OH) as a result of the higher acidity of OH sites on the former. Up to RH = 0.30 and P/P(0) = 0.30, DMMP appears to remain bonded to the surface rather than being displaced by H(2)O. H(2)O appears to have little or no effect on the total amount of DMMP adsorbed on any of these surfaces, up to an RH of 0.30 and a P/P(0) of 0.30. The results have implications for the transport of DMMP and related molecules on oxide surfaces in the environment.

Hallazgos endoscópicos en poblaciones chilenas aisladas: Isla de Pascua y Chile Chico / Endoscopic findings in isolated chilean populations: Isla de Pascua (easter island) and Chile Chico

Chile is a country with high incidence of gastrointestinal diseases, but there are Chilean populations without access to an expeditious endoscopic diagnosis. Easter Island (3.791 inhabitants) and Chile Chico (3.042 inhabitants). Objective: To describe and compare the endoscopic findings in two subgroups of Chilean population of Easter Island (Isla de Pascua) and Chile Chico. Methods: Endoscopic procedures were performed on selected subgroups from Isla de Pascua and Chile Chico during October 2008 and March 2009, in the context of health operations conducted by our hospital. Results: Seventy two patients were evaluated in Isla de Pascua and 52 in Chile Chico. The most frequent endoscopic indications in Isla de Pascua were epigastric pain (22%), heartburn (18.2%), and gastroesophageal reflux (16.2%) and in Chile Chico: gastroesophageal reflux and pirosis (36,5%), epigastric pain (19,3%), and previous gastric ulcer (5.7%). Endoscopic findings in Isla de Pascua and Chile Chico were: gastritis, 26 patients (36.1%) and 5 (9.6%); peptic ulcer 2 (2.7%) and 9 (17.2%); esophagitis 10 (13.8%) and 6 (11.5%); hiatal hernia, 9 (12.5%) and 11 (21%); and endoscopy without lesions 20 (27%) and 13 (25%), respectively. Comparing the findings in both groups the occurrence of two advanced cancers stands out (gastric and esophageal) in the population of Chile Chico; no neoplastic diseases were found in Isla de Pascua. Conclusion: The endoscopic findings in a subgroup of Chileans belonging to isolated populations are described. Differences in the type of digestive diseases suggest that these are different populations despite sharing the same nationality. Future operations will provide a better understanding of these conditions.

Introducción: Chile es un país con alta incidencia de patología digestiva, sin embargo, existen poblaciones chilenas que por situación geográfica no cuentan con acceso expedito a un diagnóstico endoscópico. Objetivo: Describir los hallazgos endoscópicos en dos subgrupos de población chilena de Isla de Pascua y Chile Chico y compararlos entre sí. Métodos: Se realizaron procedimientos endoscópicos a subgrupos seleccionados en Isla de Pascua y Chile Chico en los meses de octubre de 2008 y marzo de 2009, en el marco de los operativos de salud realizados por nuestro Hospital. Resultados: Se evaluaron 72 pacientes en Isla de Pascua y 52 en Chile Chico. Las indicaciones endoscópicas más frecuentes en Isla de Pascua son epigastralgia (22%), pirosis (18,2%) y control de reflujo gastroesofágico (16,2%) y en Chile Chico: reflujo gastroesofágico y pirosis (36,5%), epigastralgia (19,3%) y antecedente de úlcera gástrica (5,7%). Los hallazgos endoscópicos en Isla de Pascua y Chile Chico respectivamente son: gastritis 26 pacientes (36,1%) y 5 (9,6%), úlcera péptica 2 (2,7%) y 9 (17,2%), esofagitis 10 (13,8%) y 6 (11,5%), hernia hiatal 9 (12,5%) y 11 (21%), sin lesiones 20 (27%) y 13 (25%). Al comparar los hallazgos en ambos grupos destaca la presencia de dos cánceres avanzados (gástrico y esofágico) en la población de Chile Chico, sin encontrarse patología neoplásica en Isla de Pascua. Conclusión: Se describen los hallazgos endoscópicos en un subgrupo de chilenos pertenecientes a poblaciones más aisladas. Las diferencias en el tipo de patologías pesquisadas sugiere que se trata de poblaciones diferentes pese a compartir una misma nacionalidad. La realización de futuros operativos permitirá obtener un mayor conocimiento de las patologías más prevalentes en dichas poblaciones y evaluar la influencia de las...

Boundary lipids in the nicotinic acetylcholine receptor microenvironment.

The structural and functional properties of the nicotinic acetylcholine receptor (AChR), the archetype molecule in the superfamily of Cys-looped ligand-gated ion channels, are strongly dependent on the lipids in the vicinal microenvironment. The influence on receptor properties is mainly exerted by the AChR-vicinal ("shell" or "annular") lipids, which occur in the liquid-ordered phase as opposed to the more disordered and "fluid" bulk membrane lipids. Fluorescence studies from our laboratory have identified discrete sites for fatty acids, phospholipids, and cholesterol on the AChR protein, and electron-spin resonance spectroscopy has enabled the establishment of the stoichiometry and selectivity of the shell lipid for the AChR and the disclosure of lipid sites in the AChR transmembrane region. Experimental evidence supports the notion that the interface between the protein moiety and the adjacent lipid shell is the locus of a variety of pharmacologically relevant processes, including the action of steroids and other lipids. I surmise that the outermost ring of M4 helices constitutes the boundary interface, most suitable to convey the signals from the lipid microenvironment to the rest of the transmembrane region, and to the channel inner ring in particular.

Cathodoluminescence studies of the inhomogeneities in Sn-doped Ga2O3 nanowires.

Cathodoluminescence real-color imaging and spectroscopy were employed to study the properties of Ga(2)O(3) nanowires grown with different Sn/Ga ratios. The structures grown under Sn-rich conditions show large spectral emission variation, ranging from blue to red, with a green transition zone. Spectral emission changes correlate with changes in the chemical composition and structure found by energy dispersive spectroscopy and electron diffraction. A sharp transition from green to red emission correlates with a phase transition of beta-Ga(2)O(3) to polycrystalline SnO(2). The origin of the green emission band is discussed based on ab initio calculation results.

Functionalization of beta-Ga2O3 nanoribbons: a combined computational and infrared spectroscopic study.

The adsorption of H 2O, alcohols (CH 3OH and 1-octanol), and carboxylic acids (formic, acetic, and pentanoic) on beta-Ga 2O 3 nanoribbons has been studied using infrared reflection-absorption spectroscopy (IRRAS) and/or ab initio computational modeling. Adsorption energies and geometries are sensitive to surface structure, and hydrogen bonding plays a significant role in stabilizing adsorbed species. On the more stable (100)-B surface, computation shows that the physisorption of H 2O or CH 3OH is weakly exothermic whereas chemisorption via O-H bond dissociation is weakly endothermic. Experiment finds that a large fraction of a saturation coverage of adsorbed 1-octanol is displaced by exposure to acetic acid vapor. This is consistent with computational results showing that acids adsorb more strongly than methanol on this surface. The remaining alcohol, not displaced by acetic acid, suggests the presence of defects and/or (100)-A regions because computation shows that this less-stable surface adsorbs methanol more strongly than does the (100)-B. The nu(C-H) modes of adsorbed 1-octanol are easily detected whereas no adsorbed H 2O is observed even though H 2O and CH 3OH exhibit similar adsorption energies. It is inferred from this that the failure to detect H 2O on the dominant (100)-B surface results from the orientation of the physisorbed H 2O essentially parallel to the surface. Computation shows that this configuration is stabilized by H bonding. For chemisorbed formic acid, computation shows that a bridging carboxylate structure is favored over a bidentate or monodentate configuration. Computation also shows that chemisorption is favored on the (100)-A surface but physisorption is favored on the more stable (100)-B. Analysis of IRRAS data for acetic and pentanoic acids finds evidence for both types of adsorption. The carboxylate resists displacement by H 2O vapor, which suggests that carboxylic acids may be useful for functionalizing beta-Ga 2O 3 surfaces. The results provide insight into the interplay between surface structure and reactivity on an oxide surface and about the importance of hydrogen bonding in determining adsorbate structure.