ZIF-8-Based Surface Plasmon Resonance and Fabry-Pérot Sensors for Volatile Organic Compounds.

This work explores the use of ZIF-8, a metal-organic framework (MOF) material, for its use in the optical detection of volatile organic compounds (VOCs) in Fabry-Pérot and surface plasmon resonance (SPR)-based sensors. The experiments have been carried out with ethanol (EtOH) and show response times as low as 30 s under VOC-saturated atmospheres, and the estimated limit of detection is below 4000 ppm for both sensor types. The selectivity towards other VOCs is relatively poor, although the dynamics of adsorption/desorption differ for each VOC and could be used for selectivity purposes. Furthermore, the hydrophobicity of ZIF-8 has been confirmed and the fabricated sensors are insensitive to this compound, which is a very attractive result for its practical use in gas sensing devices.

Ecological speciation by sympatric host shifts in a clade of herbivorous sea slugs, with introgression and localized mitochondrial capture between species.

Host shifting in insect-plant systems was historically important to the development of ecological speciation theory, yet surprisingly few studies have examined whether host shifting drives diversification of marine herbivores. When small-bodied consumers feed and also mate on a preferred host, disruptive selection can split a population into host races despite gene flow. Support for host shifts is notably lacking for invertebrates associated with macroalgae, where the scale of dispersal by planktonic larvae often far exceeds the grain of host patchiness, and adults are typically less specialized than terrestrial herbivores. Here, we present a candidate example of ecological speciation in a clade of sea slugs that primarily consume green algae in the genus Caulerpa, including highly invasive species. Ancestral character state reconstructions supported 'sea grapes' (C. racemosa, C. lentillifera) as the ancestral host for a tropical radiation of 12 Elysia spp., with one shift onto alternative Caulerpa spp. in the Indo-Pacific. A Caribbean radiation of three species included symaptric host shifts to Rhipocephalus brevicaulis in the ancestor of E. pratensis Ortea & Espinosa, 1996, and to C. prolifera in E. hamanni Krug, Vendetti & Valdes 2016, plus a niche expansion to a range of Caulerpa spp. in E. subornata Verrill, 1901. All three species are broadly sympatric across the Caribbean but are host-partitioned at a fine grain, and distinct by morphology and at nuclear loci. However, non-recombining mtDNA revealed a history of gene flow between E. pratensis and E. subornata: COI haplotypes from E. subornata were 10.4% divergent from E. pratensis haplotypes from four sites, but closely related to all E. pratensis haplotypes sampled from six Bahamian islands, indicating historical introgression and localized "mitochondrial capture." Disruptive selective likely fueled divergence and adaptation to distinct host environments, indicating ecological speciation may be an under-appreciated driver of diversification for marine herbivores as well as epibionts and other resource specialists.

Low-dose sublingual fentanyl improves quality of life in patients with breakthrough cancer pain in palliative care.

Aim: This subanalysis of the CAVIDIOPAL study evaluated the impact of individualized management of breakthrough cancer pain (BTcP) with fentanyl on the quality of life (QoL) of advanced cancer patients in Spanish palliative care units. Patients & methods: This was a prospective, observational, multicenter study. The European Organization for Research and Treatment of Cancer's QLQ-C30 questionnaire was used at baseline (V0) and visit 28 (V28). Results: Ninety-five patients were mainly treated with 67-133 µg fentanyl, showing a notable reduction in intensity (visual analog scale: 8.0 [V0] to 4.6 [V28]), frequency and duration of BTcP episodes shortly after the first 1-2 weeks of treatment, with significantly improved QoL (global health status: 31.1 [V0] to 53.1 [V28]). Conclusion: Low-dose sublingual fentanyl effectively reduced BTcP in advanced cancer patients in palliative care units, significantly improving QoL. Clinical trial registration: NCT02840500 (ClinicalTrials.gov).

After the CAVIDIOPAL study, we carried out an additional analysis to evaluate the impact of individualized management of breakthrough cancer pain, using the analgesic drug fentanyl, on quality of life (QoL) of advanced cancer patients receiving palliative care in Spain. We performed a prospective, observational, multicenter study, in which patients' QoL was assessed using a validated questionnaire at baseline (day 0) and after 28 days of fentanyl treatment. Of the 95 patients included in the study, the majority were treated with low doses of fentanyl and showed significant pain relief. The intensity, frequency and duration of breakthrough cancer pain episodes were notably reduced shortly after the first 1­2 weeks of treatment. Moreover, patients' QoL significantly improved during fentanyl treatment from baseline to day 28. A global impression of improvement was reported by both patients and clinicians.

Impact of individualized management of breakthrough cancer pain on quality of life in advanced cancer patients: CAVIDIOPAL study.

PURPOSE: The main aim of the study was to assess the impact of individualized management of breakthrough cancer pain (BTcP) on quality of life (QoL) of patients with advanced cancer in clinical practice. METHODS: A prospective, observational, multicenter study was conducted in patients with advanced cancer that were assisted by palliative care units. QoL was assessed with the EORTC QLQ-C30 questionnaire at baseline (V0) and after 28 days (V28) of individualized BTcP therapy. Data on background pain, BTcP, comorbidities, and frailty were also recorded. RESULTS: Ninety-three patients completed the study. Intensity, duration, and number of BTcP episodes were reduced (p < 0.001) at V28 with individualized therapy. Transmucosal fentanyl was used in 93.8% of patients, mainly by sublingual route. Fentanyl titration was initiated at low doses (78.3% of patients received doses of 67 µg, 100 µg, or 133 µg) according to physician evaluation. At V28, mean perception of global health status had increased from 31.1 to 53.1 (p < 0.001). All scales of EORTC QLQ-C30 significantly improved (p < 0.001) except physical functioning, diarrhea, and financial difficulties. Pain scale improved from 73.6 ± 22.6 to 35.7 ± 22.3 (p < 0.001). Moreover, 85.9% of patients reported pain improvement. Probability of no ≥ 25% improvement in QoL was significantly higher in patients ≥ 65 years old (OR 1.39; 95% CI 1.001-1.079) and patients hospitalized at baseline (OR 4.126; 95% CI 1.227-13.873). CONCLUSION: Individualized BTcP therapy improved QoL of patients with advanced cancer. Transmucosal fentanyl at low doses was the most used drug. TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov database (NCT02840500) on July 19, 2016.

Fabrication, Characterization and Performance of Low Power Gas Sensors Based on (GaxIn1-x)2O3 Nanowires.

Active research in nanostructured materials aims to explore new paths for improving electronic device characteristics. In the field of gas sensors, those based on metal oxide single nanowires exhibit excellent sensitivity and can operate at extremely low power consumption, making them a highly promising candidate for a novel generation of portable devices. The mix of two different metal oxides on the same nanowire can further broaden the response of this kind of gas sensor, thus widening the range of detectable gases, without compromising the properties related to the active region miniaturization. In this paper, a first study on the synthesis, characterization and gas sensing performance of (GaxIn1-x)2O3 nanowires (NWs) is reported. Carbothermal metal-assisted chemical vapor deposition was carried out with different mixtures of Ga2O3, In2O3 and graphite powders. Structural characterization of the NWs revealed that they have a crystalline structure close to that of In2O3 nanowires, with a small amount of Ga incorporation, which highly depends on the mass ratio between the two precursors. Dedicated gas nanosensors based on single NWs were fabricated and tested for both ethanol and nitrogen dioxide, demonstrating an improved performance compared to similar devices based on pure In2O3 or Ga2O3 NWs.

Pursuing the Diffraction Limit with Nano-LED Scanning Transmission Optical Microscopy.

Recent research into miniaturized illumination sources has prompted the development of alternative microscopy techniques. Although they are still being explored, emerging nano-light-emitting-diode (nano-LED) technologies show promise in approaching the optical resolution limit in a more feasible manner. This work presents the exploration of their capabilities with two different prototypes. In the first version, a resolution of less than 1 µm was shown thanks to a prototype based on an optically downscaled LED using an LED scanning transmission optical microscopy (STOM) technique. This research demonstrates how this technique can be used to improve STOM images by oversampling the acquisition. The second STOM-based microscope was fabricated with a 200 nm GaN LED. This demonstrates the possibilities for the miniaturization of on-chip-based microscopes.

Nano illumination microscopy: a technique based on scanning with an array of individually addressable nanoLEDs.

In lensless microscopy, spatial resolution is usually provided by the pixel density of current digital cameras, which are reaching a hard-to-surpass pixel size / resolution limit over 1 µm. As an alternative, the dependence of the resolving power can be moved from the detector to the light sources, offering a new kind of lensless microscopy setups. The use of continuously scaled-down Light-Emitting Diode (LED) arrays to scan the sample allows resolutions on order of the LED size, giving rise to compact and low-cost microscopes without mechanical scanners or optical accessories. In this paper, we present the operation principle of this new approach to lensless microscopy, with simulations that demonstrate the possibility to use it for super-resolution, as well as a first prototype. This proof-of-concept setup integrates an 8 × 8 array of LEDs, each 5 × 5 µm2 pixel size and 10 µm pitch, and an optical detector. We characterize the system using Electron-Beam Lithography (EBL) pattern. Our prototype validates the imaging principle and opens the way to improve resolution by further miniaturizing the light sources.

Species Selection Favors Dispersive Life Histories in Sea Slugs, but Higher Per-Offspring Investment Drives Shifts to Short-Lived Larvae.

For 40 years, paleontological studies of marine gastropods have suggested that species selection favors lineages with short-lived (lecithotrophic) larvae, which are less dispersive than long-lived (planktotrophic) larvae. Although lecithotrophs appeared to speciate more often and accumulate over time in some groups, lecithotrophy also increased extinction rates, and tests for state-dependent diversification were never performed. Molecular phylogenies of diverse groups instead suggested lecithotrophs accumulate without diversifying due to frequent, unidirectional character change. Although lecithotrophy has repeatedly originated in most phyla, no adult trait has been correlated with shifts in larval type. Thus, both the evolutionary origins of lecithotrophy and its consequences for patterns of species richness remain poorly understood. Here, we test hypothesized links between development mode and evolutionary rates using likelihood-based methods and a phylogeny of 202 species of gastropod molluscs in Sacoglossa, a clade of herbivorous sea slugs. Evolutionary quantitative genetics modeling and stochastic character mapping supported 27 origins of lecithotrophy. Tests for correlated evolution revealed lecithotrophy evolved more often in lineages investing in extra-embryonic yolk, the first adult trait associated with shifts in development mode across a group. However, contrary to predictions from paleontological studies, species selection actually favored planktotrophy; most extant lecithotrophs originated through recent character change, and did not subsequently diversify. Increased offspring provisioning in planktotrophs thus favored shifts to short-lived larvae, which led to short-lived lineages over macroevolutionary time scales. These findings challenge long-standing assumptions about the effects of alternative life histories in the sea. Species selection can explain the long-term persistence of planktotrophy, the ancestral state in most clades, despite frequent transitions to lecithotrophy.

Strong Cavity-Optomechanical Transduction of Nanopillar Motion.

Nanomechanical resonators can serve as ultrasensitive, miniaturized force probes. While vertical structures such as nanopillars are ideal for this purpose, transducing their motion is challenging. Pillar-based photonic crystals (PhCs) offer a potential solution by integrating optical transduction within the pillars. However, achieving high-quality PhCs is hindered by inefficient vertical light confinement. Here, we present a full-silicon photonic crystal cavity based on nanopillars as a platform for applications in force sensing and biosensing areas. Its unit cell consists of a silicon pillar with a larger diameter at its top portion than at the bottom, which allows vertical light confinement and an energy band gap in the near-infrared range for transverse-magnetic polarization. We experimentally demonstrate optical cavities with Q factors exceeding 103, constructed by inserting a defect within a periodic arrangement of this type of pillars. Each nanopillar naturally behaves as a nanomechanical cantilever, making the fabricated geometries excellent optomechanical (OM) photonic crystal cavities in which the mechanical motion of each nanopillar composing the cavity can be optically transduced. These geometries display enhanced mechanical properties, cost-effectiveness, integration possibilities, and scalability. They also present an alternative in front of the widely used suspended Si beam OM cavities made on silicon-on-insulator substrates.

Integrative species delimitation in photosynthetic sea slugs reveals twenty candidate species in three nominal taxa studied for drug discovery, plastid symbiosis or biological control.

DNA barcoding can highlight taxa in which conventional taxonomy underestimates species richness, identifying mitochondrial lineages that may correspond to unrecognized species. However, key assumptions of barcoding remain untested for many groups of soft-bodied marine invertebrates with poorly resolved taxonomy. Here, we applied an integrative approach for species delimitation to herbivorous sea slugs in clade Sacoglossa, in which unrecognized diversity may complicate studies of drug discovery, plastid endosymbiosis, and biological control. Using the mitochondrial barcoding COI gene and the nuclear histone 3 gene, we tested the hypothesis that three widely distributed "species" each comprised a complex of independently evolving lineages. Morphological and reproductive characters were then used to evaluate whether each lineage was distinguishable as a candidate species. The "circumtropical" Elysia ornata comprised a Caribbean species and four Indo-Pacific candidate species that are potential sources of kahalalides, anti-cancer compounds. The "monotypic" and highly photosynthetic Plakobranchus ocellatus, used for over 60 years to study chloroplast symbiosis, comprised 10 candidate species. Finally, six candidate species were distinguished in the Elysia tomentosa complex, including potential biological control agents for invasive green algae (Caulerpa spp.). We show that a candidate species approach developed for vertebrates effectively categorizes cryptic diversity in marine invertebrates, and that integrating threshold COI distances with non-molecular character data can delimit species even when common assumptions of DNA barcoding are violated.

A Novel Approach for a Chip-Sized Scanning Optical Microscope.

The recent advances in chip-size microscopy based on optical scanning with spatially resolved nano-illumination light sources are presented. This new straightforward technique takes advantage of the currently achieved miniaturization of LEDs in fully addressable arrays. These nano-LEDs are used to scan the sample with a resolution comparable to the LED sizes, giving rise to chip-sized scanning optical microscopes without mechanical parts or optical accessories. The operation principle and the potential of this new kind of microscope are analyzed through three different implementations of decreasing LED dimensions from 20 µm down to 200 nm.

A cyclo olefin polymer microfluidic chip with integrated gold microelectrodes for aqueous and non-aqueous electrochemistry.

This paper presents an entirely polymeric microfluidic system, made of cyclo olefin polymer (COP), with integrated gold microband electrodes for electrochemical applications in organic media. In the present work, we take advantage of the COP's high chemical stability to polar organic solvents in two different ways: (i) to fabricate gold microelectrodes using COP as a substrate by standard lithographic and lift-off techniques; and (ii) to perform electrochemical experiments in organic media. In particular, fourteen parallel gold microelectrodes with a width of 14 microm and separated from their closest neighbour by 16 microm were fabricated by lithographic and lift-off techniques on a 188 microm thick COP sheet. A closed channel configuration was obtained by pressure-assisted thermal bonding between the COP sheet containing the microelectrodes and a microstructured COP sheet, where a 3 cm long, 50 microm wide and 24 microm deep channel was fabricated via hot embossing. Cyclic voltammetric measurements were carried out in aqueous and organic media, using a solution consisting of 5 mM ferrocyanide/ferricyanide in 0.5 M KNO(3) and 5 mM ferrocene in 0.1 M TBAP/acetonitrile, respectively. Experimental currents obtained for different flow rates ranging from 1 to 10 microL min(-1) were compared to the theoretical steady state currents calculated by the Levich equation for a band electrode (R. G. Compton, A. C. Fisher, R. G. Wellington, P. J. Dobson and P. A. Leigh, J. Phys. Chem., 1993, 97, 10410-10415). In both cases, the difference between the experimental and the predicted data is less than 5%, thus validating the behaviour of the fabricated device. This result opens the possibility to use a microfluidic system made entirely from COP with integrated microband electrodes in organic electroanalysis and in electrosynthesis.

Experimental study of the retention properties of a cyclo olefin polymer pillar array column in reversed-phase mode.

Experimental measurements to study the retention capacity and band broadening under retentive conditions using micromachined non-porous pillar array columns fabricated in cyclo olefin polymer are presented. In particular, three columns with different depths but with the same pillar structure have been fabricated via hot embossing and pressure-assisted thermal bonding. Separations of a mixture of four coumarins using varying mobile phase compositions have been monitored to study the relation between the retention factor and the ratio of organic solvent in the aqueous mobile phase. Moreover, the linear relation between the retention and the surface/volume ratio predicted in theory has been observed, achieving retention factors up to k=2.5. Under the same retentive conditions, minimal reduced plate height values of h(min)=0.4 have been obtained at retention factors of k=1.2. These experimental results are compared with the case of non-porous and porous silicon pillars. Similar results for the plate heights are achieved while retention factors are higher than the non-porous silicon column and considerably smaller than the porous pillar column, given the non-porous nature of the used cyclo olefin polymer. The feasibility of using this polymer column as an alternative to the pillar array silicon columns is corroborated.

An array of ordered pillars with retentive properties for pressure-driven liquid chromatography fabricated directly from an unmodified cyclo olefin polymer.

The current paper describes the development and characterization of a pillar array chip that is constructed out of a sandwich of cyclo olefin polymer (COP) sheets. The silicon master of a 5 cm long pillar array was embossed into the COP, yielding 4.3 microm deep pillars of 15.3 microm diameter with an external porosity of 43 % and a well designed sidewall region to avoid side wall induced band broadening. A closed channel configuration was obtained by pressure assisted thermal bonding to a non-processed COP lid. Injection of coumarin dye plugs and detection with a fluorescence microscope showed very close agreement of this channel configuration to theoretical expectations in terms of band broadening. This agreement is due to the low taper, the optimized sidewall region and the excellent bonding quality between the two polymer sheets, even at the pillar area. Under non-retained conditions (pure methanol as mobile phase), plate heights as low as 4 microm were obtained. Under retained conditions, using the native hydrophobic properties of the COP channel (in 70/30 v/v water/methanol mixture as mobile phase), a minimum plate height of 6 microm was obtained. A 4 component separation was successfully achieved, demonstrating that COP is a cheap and efficient alternative for silicon and silica based liquid chromatography formats.

A model for the response towards oxidizing gases of photoactivated sensors based on individual SnO2 nanowires.

The paper presents a quantitative model to elucidate the role of impinging photons on the final response towards oxidizing gases of light-activated metal oxide gas sensors. The model is based on the competition between oxygen molecules in air and oxidizing target gases (such as NO(2)) for the same adsorption sites: the surface oxygen vacancies (OV). The model fairly reproduces the experimental measurements of both the steady-state and the dynamic response of individual SnO(2) nanowires towards oxidizing gases. Quantitative results indicate that: (1) at room temperature NO(2) adsorbs onto OV more avidly than oxygen; (2) the flux of photons and the NO(2) concentration determine the partition of the two gas populations at the surface; and (3) the band-to-band generation of electron-hole pairs plays a significant role in the photodesorption process of gas molecules. The model also offers a methodology to estimate some fundamental parameters, such as the adsorption rates and the photodesorption cross sections of oxidizing molecules interacting with the nanowires' surface. All these results, enabled by the use of individual nanowires, provide deep insight about how to control the response of metal oxide nanowires towards oxidizing gases, paving the way to the development and consolidation of this family of low consumption conductometric sensors operable at room temperature.

Gastric cancer missed at esophagogastroduodenoscopy in a well-defined Spanish population.

BACKGROUND: Although esophagogastroduodenoscopy (EGD) is the standard procedure for the diagnosis of gastric cancer (GC), some GCs are missed. There are no published data on the missed rate of GC in Spain. AIMS: To determine the frequency and characteristics of missed GCs and assess the quality of the EGD in a specific population with GC. METHODS: Records of all patients diagnosed with gastric adenocarcinoma between 2012 and 2016 in a defined geographic area were reviewed. Missed GC was defined as a case with a prior negative EGD for cancer. Quality indicators from the prior EGDs were measured. RESULTS: From 212 cases of GC, 25 cases were excluded. Seventeen out of 187 patients had a prior EGD (9.1%). Twelve of those 17 missed GC had a prior EGD with some abnormal findings. In 6 of them, biopsies were taken. Survival was no different between patients with missed and non-missed GC. Quality indicators that failed to meet standards were recording time, image documentation, and a protocol of biopsies. CONCLUSIONS: Missed GC in an EGD in a defined population in Spain is not uncommon (9.1%). The endoscopist is an important factor in missed GC due to lack of adequate detection and sampling error. Compliance with performance of quality indicators could reduce missed GC.

ExpoApp: An integrated system to assess multiple personal environmental exposures.

To assess environmental exposures at the individual level, new assessment methods and tools are required. We developed an exposure assessment system (ExpoApp) for smartphones. ExpoApp integrates: (i) geo-location and accelerometry measurements from a waist attached smartphone, (ii) data from portable monitors, (iii) geographic information systems, and (iv) individual's information. ExpoApp calculates time spent in microenvironments, physical activity level, inhalation rate, and environmental exposures and doses (e.g., green spaces, inhaled ultrafine particles- UFP). We deployed ExpoApp in a panel study of 158 adults from five cities (Amsterdam and Utrecht- the Netherlands, Basel- Switzerland, Norwich- UK, and Torino- Italy) with an UFP monitor. To evaluate ExpoApp, participants also carried a reference accelerometer (ActiGraph) and completed a travel-activity diary (TAD). System reliability and validity of measurements were evaluated by comparing the monitoring failure rate and the agreement on time spent in microenvironments and physical activity with the reference tools. There were only significant failure rate differences between ExpoApp and ActiGraph in Norwich. Agreement on time in microenvironments and physical activity level between ExpoApp and reference tools was 86.6% (86.5-86.7) and 75.7% (71.5-79.4), respectively. ExpoApp estimated that participants inhaled 16.5 × 1010 particles/day of UFP and had almost no contact with green spaces (24% of participants spent ≥30 min/day in green spaces). Participants with more contact with green spaces had higher inhaled dose of UFP, except for the Netherlands, where the relationship was the inverse. ExpoApp is a reliable system and provides accurate individual's measurements, which may help to understand the role of environmental exposures on the origin and course of diseases.

Colaboración científica de Colombia con países de América Latina y del Caribe sobre la COVID-19 durante 2020 y 2021 / Colombia´s scientific collaboration with Latin American and Caribbean countries on COVID-19 during 2020 and 2021

Introducción: La necesidad de información por desconocimiento del Sars-CoV-2 llevó a los investigadores a generar una gran cantidad de información. Colombia es el segundo país latinoamericano con mayor producción científica sobre el Sars- CoV-2. Objetivo: caracterizar la tendencia de colaboración científica de Colombia con países de Latinoamérica y el Caribe sobre la COVID-19. Materiales y métodos: estudio bibliométrico, los registros se obtuvieron de Scopus (2020 - 2021) con los términos COVID-19, 2019-nCoV, new coronavirus, coronavirus disease 2019 y Sars-CoV-2. Se analizaron indicadores de producción, colaboración y visibilidad. Resultados: se recuperaron 77 registros. La tasa de crecimiento de la producción fue del 65,51 %. El índice de transitoriedad alcanzó el 86,69 %. El autor más productivo fue A.J. Rodríguez Morales de la Fundación Universitaria Autónoma de las Américas y Universidad Tecnológica de Pereira de Colombia (14,28 %). El 96,10 % de las investigaciones procedieron de universidades. La tasa de colaboración inter-latinoamericana alcanzó el 11,66 % con un índice de colaboración de 3,71 ± 3,09. La densidad de la red fue de 0,51. La mayor colaboración se dio con autores de México (n= 27), Perú (n= 26), Chile (n= 25) y Argentina (n= 23). Argentina presentó un mayor outdegree (176) y número de citas (55,03) y Chile un eigenvector superior (0,35). La correlación entre el número de citas y el grado de centralidad fue de 0,9. Conclusión: Colombia tiende a participar en proyectos internacionales y con países de Latinoamérica y el Caribecon mayor capacidad para desarrollar investigaciones.

Introduction: The need for information due to ignorance of Sars-CoV-2 led researchers to write and publish a large amount of information. Colombia is the second within Latin American countries with the highest scientific production on Sars- CoV-2. Objective: to characterize the trend of scientific collaboration between Colombia and Latin American and Caribbean countries on COVID-19. Materials and methods: bibliometric study, the records were acquired from Scopus (2020 - 2021) with the terms COVID-19, 2019-nCoV, new coronavirus, coronavirus disease 2019 and Sars-CoV-2. Indicators of production, collaboration and visibility were analyzed. Results: 77 records were recovered. The production growth rate was 65.51%. The transience index reached 86.69%. The most productive author was A.J. Rodríguez Morales of the Autonomous University Foundation of the Americas and the Technological University of Pereira of Colombia (14.28%). 96.10% of the investigations came from universities. The inter-Latin American collaboration rate reached 11.66% with a collaboration index of 3.71 ± 3.09. The density of the network was 0.51. The greatest collaboration occurred with authors from Mexico (n= 27), Peru (n= 26), Chile (n= 25) and Argentina (n= 23). Argentina presented a higher degree of improvement (176) and number of citations (55.03) and Chile a higher eigenvector (0.35). The connection between the number of citations and the degree of centrality was 0.9. Conclusion: Colombia tends to participate in international projects and with Latin America and the Caribbeancountries with greater capacity to develop research.

Análisis bibliométrico de los 100 artículos más citados publicados en español de Latinoamérica y el Caribe sobre COVID-19

El objetivo del estudio fue identificar los 100 artículos más citados sobre COVID-19 procedentes de Latinoamérica y el Caribe, publicados en español. Los registros se obtuvieron de la Web of Science. Se examinó: número de citas, autoría, cobertura geográfica, colaboración, revista y categorías temáticas. Los 100 artículos se publicaron en 41 revistas. La revista más citada fue Salud Pública de México (10 artículos; 75 citas). México fue el máximo exponente (28 artículos; 201 citas). Los autores más citados fueron: C. Alpuche-Aranda y E. Lazcano-Ponce, afiliados a la institución más citada, el Instituto Nacional de Salud Pública de México (n= 7). La principal categoría de la Web of Science fue Medicine, General & Internal (36 artículos; 173 citas). Epidemiología fue el tema más trabajado. No hubo correlación entre la colaboración internacional y el mayor número de citas (r= 0,15, p= 0,1). El estudio puede ayudar a reconocer la visibilidad de las investigaciones más citadas.

The aim of the study was to identify the 100 most cited articles on COVID-19 from Latin America and the Caribbean, published in Spanish. The records were obtained from the Web of Science. The following were examined: number of citations, authorship, geographic coverage, collaboration, journal and thematic categories. The 100 articles were published in 41 journals. The most cited journal was Salud Pública de México (10 articles; 75 citations). Mexico was the top performer (28 articles; 201 citations). The most cited authors were: C. Alpuche-Aranda and E. Lazcano-Ponce, affiliated with the most cited institution, the National Institute of Public Health of Mexico (n= 7). The main Web of Science category was Medicine, General & Internal (36 articles; 173 citations). Epidemiology was the most worked topic. There was no correlation between international collaboration and the highest number of citations (r= 0.15, p= 0.1). The study may help to recognize the visibility of the most cited research.

Site-Specific Growth and in Situ Integration of Different Nanowire Material Networks on a Single Chip: Toward a Nanowire-Based Electronic Nose for Gas Detection.

A new method for the site-selective synthesis of nanowires has been developed to enable material growth with defined morphology and, at the same time, different composition on the same chip surface. The chemical vapor deposition approach for the growth of these nanowire-based resistive devices using micromembranes can be easily modified and represents a simple, adjustable fabrication process for the direct integration of nanowire meshes in multifunctional devices. This proof-of-concept study includes the deposition of SnO2, WO3, and Ge nanowires on the same chip. The individual resistors exhibit adequate gas sensing responses toward changing gas concentrations of CO, NO2, and humidity diluted in synthetic air. The data have been processed by principal component analysis with cluster responses that can be easily separated, and thus, the devices described herein are in principle suitable for environmental monitoring.