Usefulness and limitations of convergent cross sorting and continuity scaling methods for their application in simulated and real-world time series.

Causality detection methods are valuable tools for detecting causal links in complex systems. The efficiency of continuity scaling (CS) and the convergent cross sorting (CSS) methods to detect causality was analysed. Usefulness and limitations of both methods in their application to simulated and real-world time series was explored under different scenarios. We find that CS is more robust and efficient than the CSS method for all simulated systems, even when increasing noise levels were considered. Both methods were not able to infer causality when time series with a marked difference in their main frequencies were analysed. Minimum time-series length required for the detection of a causal link depends on intrinsic system dynamics and on the method selected to detect it. Using simulated time series, only the CS method was capable to detect bidirectional causality. Causality detection, using the CS method, should at least include: (i) causality strength convergence analysis, (ii) statistical tests of significance, (iii) time-series standardization, and (iv) causality strength ratios as a strength indicator of relative causality between systems. Causality cannot be detected by either method in simulated time series that exhibit generalized synchronization.

Simultaneous determination of lead and antimony in gunshot residue using a 3D-printed platform working as sampler and sensor.

3D-printing is an emerging technique that enables the fast prototyping of multiple-use devices. Herein we report the fabrication of a 3D-printed graphene/polylactic acid (G-PLA) conductive electrode that works as a sampler and a voltammetric sensor of metals in gunshot residue (GSR) using a commercially-available G/-PLA filament. The 3D-printed surface was used as swab to collect GSR and next submitted to a square-wave voltammetric scan for the simultaneous detection of Pb2+ and Sb3+. The proposed sensor presented excellent analytical performance, with limit of detection values of 0.5 and 1.8 µg L-1 to Pb2+ and Sb3+, respectively, and linear ranges between 50 and 1500 µg L-1. Sampling was performed through the direct contact of G-PLA electrode in hands and clothes of shooters, followed by immersion in the electrochemical cell in the presence of supporting electrolyte for the SWASV scan. The proposed method showed a great performance in the recovery, identification and semi-quantification of Pb2+ and Sb3+ in the evaluated samples without the need for sample preparation. Moreover, the device can be reused as sampler and sensor (until three times without loss of electrochemical performance) and the fabrication is reproducible (RSD = 7%, for three different devices). Hence, this 3D-printed material is an excellent candidate for the analysis of GSR, an indispensable analysis in the forensic field.

Quantifying harmful algal bloom thresholds for farmed salmon in southern Chile.

Harmful algal blooms (HABs) have affected salmon farms in Chile since the early 1970's, causing massive losses in fish. Two large HABs occurred in 2002 and 2009, during which Alexandrium catenella blooms killed tons of salmon over an extended geographic area in southern Chile. At the beginning of 2016, high and persistent densities of Pseudochattonella cf. verruculosa and A. catenella were detected in the estuarine and marine ecosystems of southern Chile. Mortality for this latter event reached 27 million salmon and trout (i.e. 39,000 tons). Unfortunately, the threshold concentrations of algae that could be harmful to the health of farmed salmon in southern Chile have not yet been quantified. Here, to protect fish farms from HABs, critical concentration levels, i.e. thresholds at which the behavior of farmed Salmo salar is affected by harmful algae were quantified using generalized linear mixed models (GLMM). An extensive database from southern Chile covering the period from 1989 to 2016 was analyzed. The database included salmon behavior, cell abundance of microalgae and oceanographic factors. For both species analyzed, the higher the cell abundance, the greater the probability of detecting anomalous behavior. A threshold of 397 cells/mL was estimated for A. catenella, although it can increase up to ca. >975 cells/mL at a Secchi depth >6 m and up to 874 cells/mL during flood tide. A threshold value <1 cell/mL for Pseudochattonella cf. verruculosa was found to be associated with anomalous salmon behavior, which significantly increased at a water temperature of 11 °C. Evidence for a relationship between fish behavior and mortality is provided.

Prevalencia del virus papiloma humano en pacientes con diagnóstico de carcinoma escamoso de la cavidad oral / Human papilloma virus prevalence in patients diagnosed with squamous carcinoma oral cavity

Aim: To establish the prevalence of HPV in patients with diagnose of Oral Squamous cell carcinoma, treated in the Instituto nacional del Cáncer in fresh tumoral samples. methods: Cross-sectional study. The inclusion criteria were patients over 18 years, histological diagnosis of Oral Squamous cell carcinoma, that haven’t received any previous cancer treatment, in normal physical and mental conditions. All patients signed an informed consent. Samples consisting of fresh biopsies of lesions with clinical and pathological diagnosis were made. The samples were processed in the Programme of Virology, Faculty of Medicine, Universidad de Chile, through PCR and genotyped by Linear Array® (ROCHE). Results: The prevalence of VPH obtained in this patients was of 9.09% (2/22), corresponding 1 to VPH 56. The positive patients for VPH resulted to be a man of 35 years and a woman of 73 years (9%). Conclusion: The prevalence of HPV in this type of patients was 9.09%, similar than the international publications.

Objetivos: Determinar la prevalencia del virus papiloma humano (VPH) en pacientes con diagnóstico de carcinoma escamoso de la cavidad oral (COCE), atendidos en el Instituto nacional del Cáncer (INCANCER). material y método: Estudio de corte transversal. Criterios de inclusión: pacientes mayores de 18 años, con diagnóstico histológico de COCE, que no hubiesen recibido ningún tratamiento oncológico previo, en condiciones físicas y mentales normales. Todos los pacientes firmaron el consentimiento informado. Se les realizó una entrevista y se tomaron muestras que consistieron en biopsias frescas de lesiones con diagnóstico clínico y anatomopatológico de COCE. Las muestras se procesaron en el Programa de Virología de la Facultad de Medicina de la Universidad de Chile, a través de PCR y se genotipificaron mediante Linear Array® (ROCHE). Resultados: La prevalencia de VPH obtenida en estos pacientes fue de un 9,09% (2/22), correspondiendo 1 a VPH 56. Los pacientes positivos para VPH resultaron ser un hombre de 35 años y una mujer de 73 años (9%). Conclusión: La prevalencia del VPH en este tipo de pacientes fue de 9,09%, similar a las publicaciones internacionales.

Human papillomavirus infection in oral squamous cell carcinomas from Chilean patients.

Human papillomavirus (HPV) is the causal agent of cervical, anogenital and a subset of oropharyngeal carcinomas. In addition, the role of HPV in oral carcinogenesis has been suggested, although the findings are inconclusive. In this study, using conventional polymerase chain reaction (PCR) and genotyping by specific PCR and DNA sequencing, we analyzed the HPV presence in 80 oral squamous cell carcinomas (OSCCs) from Chilean subjects. In addition, we determined the expression of p16, p53, pRb and Ki-67 using immunohistochemistry (IHC). The CDKN2A (p16) promoter methylation was evaluated using methylation-specific PCR (MSP). HPV sequences were found in 9/80 (11%) OSCCs. Non-statistically significant association with p53, pRb, Ki-67 and p16 levels were found (p=0.77; 0.29; 0.83; 0.21, respectively). HPV-16 and 18 were the most prevalent HPV genotypes in 8/9 (89%) OSCCs. In addition, CDKN2A (p16) was methylated in 39% of OSCCs. No association with HPV presence (p=0.917) was found. These results suggest that HPV positive OSCCs are entities that do not resemble the molecular alterations of HPV-associated tumors in a Chilean population. More studies are warranted to determine the role of HPV in OSCCs.

Sarcomatoid (spindle cell) carcinoma of tongue: a report of two cases.

Sarcomatoid Carcinoma (SC) is an unusual and aggressive variant of squamous cell carcinoma, which frequently recurs and metastasizes; for this reason, the right diagnosis is very important. It is considered to be a biphasic tumor made up of cells from squamous and spindle cells carcinoma with a sarcomatous aspect, but of epithelial origin. The diagnosis often represents a clinical-pathological challenge where the study with immunohistochemical technique (IHC) is key to the histopathological diagnosis. The reported cases related to oral mucosa are limited. In this work we present two SC cases where the use of IHC allowed us to achieve a conclusive diagnosis.