This study performed barcoded multiplex pyrosequencing with a 454 FLX instrument to compare the microbiota of dental root canal infections associated with acute (symptomatic) or chronic ...(asymptomatic) apical periodontitis. Analysis of samples from 9 acute abscesses and 8 chronic infections yielded partial 16S rRNA gene sequences that were taxonomically classified into 916 bacterial species-level operational taxonomic units (OTUs) (at 3% divergence) belonging to 67 genera and 13 phyla. The most abundant phyla in acute infections were Firmicutes (52%), Fusobacteria (17%) and Bacteroidetes (13%), while in chronic infections the dominant were Firmicutes (59%), Bacteroidetes (14%) and Actinobacteria (10%). Members of Fusobacteria were much more prevalent in acute (89%) than in chronic cases (50%). The most abundant/prevalent genera in acute infections were Fusobacterium and Parvimonas. Twenty genera were exclusively detected in acute infections and 18 in chronic infections. Only 18% (n = 165) of the OTUs at 3% divergence were shared by acute and chronic infections. Diversity and richness estimators revealed that acute infections were significantly more diverse than chronic infections. Although a high interindividual variation in bacterial communities was observed, many samples tended to group together according to the type of infection (acute or chronic). This study is one of the most comprehensive in-deep comparisons of the microbiota associated with acute and chronic dental root canal infections and highlights the role of diverse polymicrobial communities as the unit of pathogenicity in acute infections. The overall diversity of endodontic infections as revealed by the pyrosequencing technique was much higher than previously reported for endodontic infections.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Context: Lobophora variegata J.V. Lamouroux (Dictyotaceae) is a brown marine alga widely encountered in the Brazilian sea coast that presents high content of fucans. Anti-inflammatory effects of ...fucans are reported mostly in models in vitro, but little is known about its effects in vivo.
Objective: To investigate vascular and cellular effects of a sulfated polysaccharide from the brown marine algae L. variegata (SP-Lv) in acute inflammatory models.
Materials and methods: SP-Lv was isolated by DEAE-cellulose and analyzed by agarose gel electrophoresis and evaluated for its inhibitory effect on paw edema, vascular permeability, leukocyte migration and peritoneal nitrite content induced by zymosan in Wistar rats. Anticoagulant activities and possible systemic toxicity were also evaluated.
Results: SP-Lv inhibited the paw edema (120 min: 1.42 ± 0.11 vs. 0.95 ± 0.05 mL), plasma exudation (21.53 ± 0.62 vs. 11.96 ± 0.68 μg/g), nitrite content (4.42 ± 0.33 vs. 2.86 ± 0.003 μM) and leukocyte migration (5.15 ± 1.21 vs. 1.99 ± 0.16 cells/103 mL) induced by zymosan. SP-Lv and l-NAME reduced the paw edema (60-120 min) elicited by l-arginine. However, at 180 min SP-Lv effect was more accentuated and sustained until 240 min, while that of l-NAME was abolished. Similarly to indomethacin, SP-Lv inhibited the entire edema time-course induced by phospholipase A2, except for the time of 60 min.
Discussion and conclusion: The anti-edematogenic effect of SP-Lv seems to occur via inhibition of nitric oxide synthase and cyclooxygenase activities. These results suggest a potential applicability of polysaccharides from alga origin in acute inflammatory conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Clinical diagnosis has always been dependent on the efficient immobilization of biomolecules in solid matrices with preserved activity, but significant developments have taken place in recent years ...with the increasing control of molecular architecture in organized films. Of particular importance is the synergy achieved with distinct materials such as nanoparticles, antibodies, enzymes, and other nanostructures, forming structures organized on the nanoscale. In this review, emphasis will be placed on nanomaterials for biosensing based on molecular recognition, where the recognition element may be an enzyme, DNA, RNA, catalytic antibody, aptamer, and labeled biomolecule. All of these elements may be assembled in nanostructured films, whose layer-by-layer nature is essential for combining different properties in the same device. Sensing can be done with a number of optical, electrical, and electrochemical methods, which may also rely on nanostructures for enhanced performance, as is the case of reporting nanoparticles in bioelectronics devices. The successful design of such devices requires investigation of interface properties of functionalized surfaces, for which a variety of experimental and theoretical methods have been used. Because diagnosis involves the acquisition of large amounts of data, statistical and computational methods are now in widespread use, and one may envisage an integrated expert system where information from different sources may be mined to generate the diagnostics.
2,5-Hexanedione (2,5-HD) is the most important metabolite of n-hexane and methyl ethyl ketone in human urine. Urinary 2,5-HD is used as a biomarker for biological monitoring of workers exposed to ...n-hexane. A simple method using headspace solid-phase microextraction (HS-SPME) and gas chromatography (GC) equipped with a flame-ionization detector (FID) was developed. The parameters that affect the HS-SPME-GC-FID process were optimized (i.e., fiber coating, sample volume, adsorption and heating time, salt addition, and extraction temperature). The assay presented linearity in the range of 0.075 to 20.0 mg/L, precision (coefficient of variation < 7.0%), and detection limit of 0.025 mg/L for 2,5-HD in urine. The method was successfully applied to the analysis of 2,5-HD in urine samples from eight workers occupationally exposed to n-hexane in shoemaker's glue.
ABSTRACT The aim of this study was to determine the effective diffusion coefficient and the thermodynamic properties of Bauhinia forficata Link leaves, considering two forms of thickness measurements ...and to describe the process by fitting mathematical models. The leaves were collected, taken to the laboratory and prepared to start the drying process in which four temperatures (40, 50, 60 and 70 °C) were applied. After the drying process, the effective diffusion coefficient was determined through the theory of diffusion in liquid, allowing to obtain the values of the activation energy, enthalpy, entropy and Gibbs free energy. The description of the drying process was performed by setting the thirteen mathematical models used to represent constant drying of agricultural products. The Valcam model was selected to represent the drying kinetics B. forficata Link. Increased temperature promotes: decreasing enthalpy and entropy; increasing Gibbs free energy and effective diffusion coefficient. The effective diffusion coefficient is higher when the rib thickness is considered; thus, it is recommended to standardize and/or specify the points of measurement of leaf thickness.
RESUMO Objetivou-se, neste trabalho, determinar o coeficiente de difusão efetivo e as propriedades termodinâmicas das folhas de Bauhinia forficata Link, considerando-se duas formas de medição de espessura, bem como descrever o processo de secagem por meio do ajuste de modelos matemáticos. As folhas foram coletadas, levadas ao laboratório e preparadas para dar início ao processo de secagem em quatro temperaturas (40, 50, 60 e 70 °C). Após a secagem determinou-se o coeficiente de difusão efetivo por meio da teoria da difusão líquida permitindo a obtenção dos valores da energia de ativação, entalpia, entropia e energia livre de Gibbs. Já a descrição do processo de secagem foi realizada por meio do ajuste de treze modelos matemáticos constantemente utilizados para representação de secagem de produtos agrícolas. O modelo de Valcam foi selecionado para representar a cinética de secagem de folhas de B. forficata Link. O aumento da temperatura promove: decréscimo de entalpia e entropia; aumento da energia livre de Gibbs e do coeficiente de difusão efetivo. O coeficiente de difusão efetivo é maior quando se considera a espessura da nervura, recomendando-se a padronização e/ou especificação dos pontos de medição da espessura da folha.
The dental profession has endured unprecedented disruption amid COVID-19. Novel stressors have included a high risk of occupational exposure to COVID-19, financial losses, and stricter infection ...prevention and control requirements. The present study investigated the longitudinal impact of COVID-19 on the stress and anxiety levels of a cohort of Canadian dentists (N = 222) between September 2020 and October 2021. Salivary cortisol was selected as a biomarker of mental stress, and 10 sets of monthly saliva samples (2,131 in total) were self-collected, sent to our laboratory in prepaid courier envelopes, and analyzed by enzyme-linked immunosorbent assay. To assess COVID-19 anxiety, 9 monthly online questionnaires were administered, comprising a general COVID-19 anxiety instrument and 3 items regarding the impact of dentistry-related factors. Bayesian log-normal mixed effect models were fitted to estimate the longitudinal trajectory of salivary cortisol levels and their association with the disease burden of COVID-19 in Canada. After accounting for age, sex, vaccination status, and the diurnal rhythm of cortisol secretion, a modest positive association was found between dentists’ salivary cortisol levels and the count of COVID-19 cases in Canada (96% posterior probability). Similarly, the self-reported impact of dentistry-related factors, such as fear of getting COVID-19 from a patient or coworker, was greatest during peaks of COVID-19 waves in Canada; however, general COVID-19 anxiety decreased consistently throughout the study period. Interestingly, at all collection points, the majority of participants were not concerned about personal protective equipment. Overall, participants reported relatively low rates of psychological distress symptoms in relation to COVID-19, a result that should be reassuring for the dental community. Our findings strongly suggest a link between self-reported and biochemical measurements of stress and anxiety in Canadian dentists during the COVID-19 pandemic.
Aim
To microscopically examine the cleanliness of root canal walls that remained unprepared as revealed by micro‐CT.
Methodology
The root canals of 10 freshly extracted mandibular premolars with ...necrotic pulps and apical periodontitis along with the mesiobuccal canals of 11 mandibular molars with vital pulps were prepared using Reciproc instruments R40 and R25, respectively, and 2.5% sodium hypochlorite irrigation. Specimens were scanned in micro‐CT before and after preparation, and the unprepared areas were identified. The outer root surface corresponding to the untouched areas was marked on each root third to guide further analysis using histological (for teeth with vital pulps) and scanning electron microscopic (SEM; for necrotic teeth) examination. In the teeth with vital pulps, the root canal area occupied by tissue remnants was calculated. In SEM analysis of teeth with necrotic pulps, scores were attributed for the amount of debris on the untouched areas.
Results
The proportion of unprepared areas in the mesiobuccal molar canals was 18.1% and 9.6% over the full canal length and apical canal, respectively. In premolars, corresponding figures were 34.6% and 17.6%, respectively. Histological analysis of canals with vital pulps revealed tissue remnants over the untouched walls almost exclusively in the apical canal. SEM analysis of the canals with necrotic pulps revealed debris along the untouched walls in all root canal thirds.
Conclusion
The areas that remain untouched by Reciproc instruments used with 2.5% NaOCl irrigation as revealed by micro‐CT analysis were usually covered with debris, in the form of pulp tissue remnants, bacteria and dentine chips, especially in the apical root canal.
Several upcoming satellite missions have core science requirements to produce data for accurate forest aboveground biomass mapping. Largely because of these mission datasets, the number of available ...biomass products is expected to greatly increase over the coming decade. Despite the recognized importance of biomass mapping for a wide range of science, policy and management applications, there remains no community accepted standard for satellite-based biomass map validation. The Committee on Earth Observing Satellites (CEOS) is developing a protocol to fill this need in advance of the next generation of biomass-relevant satellites, and this paper presents a review of biomass validation practices from a CEOS perspective. We outline the wide range of anticipated user requirements for product accuracy assessment and provide recommendations for the validation of biomass products. These recommendations include the collection of new, high-quality in situ data and the use of airborne lidar biomass maps as tools toward transparent multi-resolution validation. Adoption of community-vetted validation standards and practices will facilitate the uptake of the next generation of biomass products.
The South American tomato pinworm,
Tuta absoluta
(Meyrick) (Lepidoptera: Gelechiidae), is an invasive pest difficult to control. Insecticide application is quite common and remains the prevalent ...control method particularly in open-field cultivation systems. As a result, insecticide resistance to many chemical classes of insecticides has been described both in South America and in Europe. The development of insecticide resistance is relatively fast in this species, and the main mechanisms involved are altered target-site sensitivity and/or enhanced detoxification, depending on the chemical class. However, insecticide resistance mechanisms do not differ between South America and Europe and are mainly due to simple genotype variations leading to high levels of resistance. The presence of resistance alleles at low frequency, especially against newer chemistry, is of major concern, as they tend to spread with the invasions making tomato pinworm particularly difficult to control. The monitoring methods and management programmes developed for the species benefited from the pro-activity of the Insecticide Resistance Action Committee and its country groups, particularly in Brazil and Spain. Bioassay methods were developed, resistance monitoring activities initiated and resistance management guidance was provided. The implementation of integrated control programmes and appropriate resistance management strategies as part of such programs is of utmost importance to keep tomato pinworm infestations under economic damage thresholds, thus guaranteeing sustainable yields.
Spinel ferrites are versatile, low-cost, and abundant metal oxides with remarkable electronic and magnetic properties, which find several applications. Among them, they have been considered part of ...the next generation of electrochemical energy storage materials due to their variable oxidation states, low environmental toxicity, and possible synthesis through simple green chemical processing. However, most traditional procedures lead to the formation of poorly controlled materials (in terms of size, shape, composition, and/or crystalline structure). Thus, we report herein a cellulose nanofibers-mediated green procedure to prepare controlled highly porous nanocorals comprised of spinel Zn-ferrites. Then, they presented remarkable applications as electrodes in supercapacitors, which were thoroughly and critically discussed. The spinel Zn-ferrites nanocorals supercapacitor showed a much higher maximum specific capacitance (2031.81 F g
at a current density of 1 A g
) than Fe
O
and ZnO counterparts prepared by a similar approach (189.74 and 24.39 F g
at a current density of 1 A g
). Its cyclic stability was also scrutinized via galvanostatic charging/discharging and electrochemical impedance spectroscopy, indicating excellent long-term stability. In addition, we manufactured an asymmetric supercapacitor device, which offered a high energy density value of 18.1 Wh kg
at a power density of 2609.2 W kg
(at 1 A g
in 2.0 mol L
KOH electrolyte). Based on our findings, we believe that higher performances observed for spinel Zn-ferrites nanocorals could be explained by their unique crystal structure and electronic configuration based on crystal field stabilization energy, which provides an electrostatic repulsion between the d electrons and the p orbitals of the surrounding oxygen anions, creating a level of energy that determines their final supercapacitance then evidenced, which is a very interesting property that could be explored for the production of clean energy storage devices.
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