Fluorescence Spectroscopy Applied in the Identification of Lubricant Oils

In this work, we report the use of fluorescence spectroscopy to identify lubricant oils. Optical characterization was performed in four commercial lubricant oils that are used in reciprocating compressors. Mid-infrared absorption of samples indicates the presence of aromatic rings showing bands at 1605 cm-1 (C=C stretching) and 815 cm-1 (C–H stretch out of plane). UV-VIS absorption spectra show bands of di- and polyaromatic rings (around 230 nm and 260 nm, respectively). By exciting the samples at 360 nm, a broad emission band centered at 440 nm is observed, indicating that this excitation is appropriate to be used for the diagnosis of oil presence in the environment. DOI: http://dx.doi.org/10.17807/orbital.v10i1.103

Fluorescence Spectroscopy and Silica Gel Applied as a Tool for Capture and Detection of Compressor Lubricant Oils

Here, we report the use of fluorescence spectroscopy for the identification of lubricant oils used in reciprocating compressors, and the use of silica gel as an adsorbent to capture lubricant oil vapors. The silica gel was tested for adsorption of lubricant oil vapors, by heating the samples at 200°C, the emission spectrum of the lubricant oils is observed on the silica gel layer, over 20 min of heating. The spectrum of the lubricant oils over the silica gel layer presents a redshift, an indication of the degradation effect. In order to investigate this effect on the optical properties, we conducted an experiment by heating the samples at (130 ± 4) °C, and collected at different times. The MID-infrared absorption of the samples presents bands of oxygen-containing groups at 1010 and 1050 cm-1, and NIR infrared absorption measurements at 3444 cm-1 show an increase in the hydroperoxide band during the degradation time. These two results indicate that the oxidation process is associated with the observed redshift of the absorption and emission bands in lubricant oils and over the adsorbent layer

Reproductive Status of the social wasp Polistes versicolor (Hymenoptera, Vespidae)

A fundamental feature in the evolution of social insects is the separation of castes, and the presence of wide differentiation between castes indicates a more advanced degree of sociability. In this study, we evaluated factors that indicate the reproductive status of females in colonies of the social wasp Polistes versicolor. The reproductive status of each female was examined by measuring nine morphometric characters, by the cuticular chemical profile, insemination and by her relative age. We conclude that in P. versicolor colonies there are 3 female groups that show cuticular chemical profile difference. The first group belong to females with ovarioles filamentous, typical of workers; the second is females with ovarioles intermediates; and the third is a group of queens, which are older females, inseminated and with greater degree of ovarian development found among all females. On the other hand, there was no significant morphological differences between these female groups. Therefore, although no significant morphological differences among females there are other factors such as the cuticular chemical composition that is an indicative of reproductive physiological condition of female in the colony

Fluorescence Spectroscopy Applied in the Identification of Lubricant Oils

In this work, we report the use of fluorescence spectroscopy to identify lubricant oils. Optical characterization was performed in four commercial lubricant oils that are used in reciprocating compressors. Mid-infrared absorption of samples indicates the presence of aromatic rings showing bands at 1605 cm-1 (C=C stretching) and 815 cm-1 (C–H stretch out of plane). UV-VIS absorption spectra show bands of di- and polyaromatic rings (around 230 nm and 260 nm, respectively). By exciting the samples at 360 nm, a broad emission band centered at 440 nm is observed, indicating that this excitation is appropriate to be used for the diagnosis of oil presence in the environment. DOI: http://dx.doi.org/10.17807/orbital.v10i1.103

Evaluation of Inter and Intraspecific Differences in the Venom Chemical Compositions of Polybia paulista Wasps and Ectatomma brunneum Ants Using FTIR-PAS

Wasps can synthesize chemical compounds called venom whose function is to overcome prey and assist in defense of the colonies. Geographic Parameters such as sex, age, the season of the year, and diet determined the composition of the venom location, genetics, environment. However, studies on the compositional variability of venom are still limited due to the difficulty in obtaining samples and the complexity of these substances. This work describes the use of the Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) to investigate inter- and intraspecific variability in the venom chemical composition (VCC) of the social wasp Polybia paulista (Von Ihering 1896) and the ant Ectatomma brunneum (Smith 1858). The results reveal significant differences in VCC among the ant and wasp, even for samples obtained from the same environment. The genetic component, therefore, seemed to be the predominant factor determining the compounds present. The findings also showed that exogenous factors, such as diet, could also be responsible for intraspecific differences, especially in wasps. The FTIR-PAS technique proved to be a reliable way of assessing intra- and interspecific differences in social Hymenoptera VCC

Low Temperature Synthesis of Several Titanium Dioxide Solid Solutions through the Sol-Gel Method

Titanium dioxide powders constituted by anatase single phase are very useful to understand several properties of that semiconductor applied as photocatalyst material. In addition, the reconstructive transformation involved in the anatase-to-rutile phase transition is also dependent of compositional and structural characteristics, which is consequence of the xerogel precursors. In this work, it was provided some structural investigation and the thermal event associated to different compositions of titanium dioxide xerogel samples obtained by Sol-Gel method. It was prepared two different doped-sample sets, one with bared titanium dioxide matrix and other with 10 mol% of zirconium-silicon one, and both sample sets were submitted to doping with 2 mol% of cation pairs, taking in account the ionic radii and oxidation states. The small and pentavalent vanadium cation was combined with trivalent and bigger lanthanum and bismuth ones, in order to provide non strained unit cell making an average values for ionic radii and oxidation states, taking in account the tetravalent titanium cation. By thermal analysis, X-ray diffractometry, FTIR and Raman spectroscopies it was possible to demonstrate the insertion of bigger dopants as lanthanum and bismuth, as well as the smaller one as vanadium, which are usually dopants not supported in isolated forms were successfully incorporated to anatase phase when combined as expected in previous composition design stage. DOI: http://dx.doi.org/10.17807/orbital.v10i1.103

Linear Alkanes and Reproductive Status of Polistes versicolor (Hymenoptera: Vespidae) Females in Winter Aggregates

Female wasps such as Polistes versicolor can form aggregates to face weather conditions that are not suitable to sustain their colonies. The interactions between individuals in these aggregates, just as in other associations, are probably facilitated by chemical signals. Of these compounds some of the most efficient during social interactions of insects are those called contact pheromones or superficial pheromones. This special type of pheromones, known as cuticular hydrocarbons, can be found in insects cuticle. They facilitate the differentiation of caste, species and nestmates, and may be important indicators of dominance as well as fertility. Some studies indicate that linear alkanes are important cuticular compounds for intraspecific recognition and discrimination. The aim of this study was to evaluate the relationship between reproductive physiologic condition and the linear alkanes present in the cuticle of females of P. versicolor in aggregates employing Gas Chromatography with Flame Ionization Detector (GC-FID). Females from distinct aggregates were differentiated by the chemical composition of their cuticle. In each aggregate, there was difference in cuticular chemical composition between females with different ovarian development degrees, allowing the distinction between inseminated and non-inseminated females

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Study of optical properties of crystalline fibers of CVO:nd3+ and CMO: nd3+/nb5+

O presente trabalho apresenta um amplo estudo das propriedades espectroscópicas de fibras cristalinas de CMO:NdNbO4 e CVO:Nd3+, visando aplicações como novos meios ativos excitados por laser de diodo. As fibras em estudo, foram crescidas pela técnica de LHPG (Laser Heated Pedestal Growth) a qual permitem uma rápida obtenção de fibras, em dimensões já apropriadas para a confecção de mini lasers, sem a utilização de cadinhos, com excelente qualidade cristalina e baixa perda de material. Para uma completa caracterização, foram realizados os cálculos de Judd Ofelt, baseando-se nos espectros de absorção óptica, como ferramenta para a calibração e interpretação dos experimentos de luminescência, emissão estimulada (SE), absorção do estado excitado (ESA) obtido por duas técnicas: (a) pela técnica de bombeio e feixe de prova contínuos em um esquema de dupla modulação e (b) pela técnica de excitação do estado excitado (ESE). Estes resultados mostraram que ambos os materiais possuem baixos valores de seção de choque ESA na principal região de emissão laser de materiais dopados com Nd3+ 4F3/2 &#8594; 4I11/2 (~1070nm). A presença de bandas largas observadas nos espectros de luminescência e absorção óptica e um número de transições maior do que esperado observado nos espectros de absorção óptica a baixa temperatura, indicaram a provável existência de multisítios em ambos cristais de CVO:Nd3+ e CMO:NdNbO4. Para quantificar e caracterizar os multisítios de Nd3+ nas amostras, foram realizados experimentos de excitação óptica, seleção de sítios por excitação laser e luminescência seletiva, demonstrando que a amostra de CVO:Nd3+ possui um grande numero de sítios e a amostra de CMO:NdNbO4 possui sete sítios diferentes, justificando o comportamento de bandas largas observado nos espetros de absorção óptica e luminescência. Os valores das seções de choque de absorção óptica (&#963;GSA=4,1x\'10-20cm2 para o CVO e &#963;GSA=5,5x10-20cm2 para o CMO:NdNbO4) e de emissão estimulada, para ambos os materiais (&#963;e=5,5x10-20cm2 para o CMO:NdNbO4 e 13,3x10-20cm2 para o CVO:Nd3+), estão na faixa de importantes meios ativos laser que exibem propriedades multisítios e uma largura de linha de absorção óptica em 810nm (&#916;&#955;GSA=11nm para o CVO e &#916;&#955;GSA=11,5nm para o CMO) maior que muitos importantes meios ativos como YAG:Nd3+ ou GGG:Nd3+ colocando-os em vantagem em relação a estes e muitos outros materiais, para excitação com laser de diodo, justificando a importância do trabalho apresentado e o estudo desses materiais.The present work release an extensive study of spectroscopic properties on CMO:NdNbO4 and CVO:Nd3+ single crystal fibers, in searching for new laser materials activated with diode laser. The fibers were grown by LHPG (laser Heated Pedestal Growth) technique that permits a fast production of fibers with appropriate dimension for mini laser construction, without the use of crucible, with excellent crystalline quality and low waste of material. For a full optical characterization, it was performed the Judd Ofelt analysis based on the measured absorption spectra as a tool for calibration and interpretation of the experiments of luminescence, stimulated emission (SE), excited-state absorption (ESA) using two different techniques: (a) by the double modulate pump and probe continuous wave technique and (b) by the excited-state excitation (ESE) technique. These results show that both materials have low ESA cross-section values in the main expected laser region 4F3/2 &#8594; 4I11/2 of Nd3+ - doped materials (-1070nm). The existence of broad bands in the luminescence and optical absorption spectra and a number of transitions more than expected as observed in the low temperature absorption spectra suggest the existence of multisites in both crystals of CVO:Nd3+ e CMO:NdNbO4. In order to quantify and characterize the multisites of Nd3+ in the samples, experiments were realized of optical excitation, site selective laser excitation and selective luminescence. These experiments shown that CVO:Nd3+ has a large number of different sites and the CMO:NdNbO4 has seven different sites, justifying the broad band behavior observed on the luminescence and optical absorption experiments. The values of absorption cross-sections (&#963;GSA=4,1x\'10-20cm2 for CVO and &#963;GSA=5,5x10-20cm2 for CMO:NdNbO4) and emission cross-sections (&#963;e=5,5x10-20cm2 for the CMO:NdNbO4 and 13,3x10-20cm2 for CVO:Nd3+) among important laser materials that have multisites properties and a FWHM of absorption at 810nm (&#916;&#955;GSA=11nm for CVO and &#916;&#955;GSA\'=11,5nm for CMO) broader than many other active laser medium like YAG:Nd3+ or GGG:Nd3+ suggesting these materials to be on advantage from many others lasers materials using diode laser excitation, justifj4ng the important of the present work and the study of these material