Cyanotoxins and water quality parameters as risk assessment indicators for aquatic life in reservoirs.

We assessed the extent of pollution in an essential public water supply reservoir (southeastern Brazil). An environmental monitoring study was performed at the Billings Reservoir (at the water catchment site) to assess the water quality in 2017, 2018, and 2019. Physicochemical parameters were analyzed, quantifying the total cyanobacteria and the cyanotoxins microcystins (MCs) and saxitoxins (SXTs), as well as their possible ecological risk to the aquatic environment. We also determined metals and metalloids (As, Ba, Cd, Pb, Cu, Cr, Fe, Mn, Ni, Zn, and Sb) and fecal bacteria (Escherichia coli). Monthly samplings were performed for 2017, 2018, and 2019 (totaling 36 sampling campaigns). Metals, metalloids, and E. coli values were below the maximum limit allowed by the Brazilian legislation. High concentrations of total cyanobacteria (3.07 × 104 - 3.23 × 105 cells/mL), microcystin variants MC-LR (0.67-23.63 µg/L), MC-LA (0.03-8.66 µg/L), MC-RR (0.56-7.92 µg/L), and MC-YR (0.04-1.24 µg/L), as well as the saxitoxins GTX2 (0.18-5.37 µg/L), GTX3 (0.13-4.40 µg/L), and STX (0.12-2.92 µg/L) were detected. From an ecotoxicological point of view, the estimated values for the risk quotient (RQ) for microcystins and saxitoxins were largely greater than 1, indicating a high risk to aquatic life. Therefore, further efforts need to be made to delay the eutrophication of the reservoir.

Fracture incidence of Reciproc instruments during root canal retreatment performed by postgraduate students: a cross-sectional retrospective clinical study.

OBJECTIVES: To evaluate the fracture incidence of Reciproc R25 instruments (VDW) used during non-surgical root canal retreatments performed by students in a postgraduate endodontic program. MATERIALS AND METHODS: From the analysis of clinical record cards and periapical radiographs of root canal retreatments performed by postgraduate students using the Reciproc R25, a total of 1,016 teeth (2,544 root canals) were selected. The instruments were discarded after a single use. The general incidence of instrument fractures and its frequency was analyzed considering the group of teeth and the root thirds where the fractures occurred. Statistical analysis was performed using the χ2 test (p < 0.01). RESULTS: Seven instruments were separated during the procedures. The percentage of fracture in relation to the number of instrumented canals was 0.27% and 0.68% in relation to the number of instrumented teeth. Four fractures occurred in maxillary molars, 1 in a mandibular molar, 1 in a mandibular premolar and 1 in a maxillary incisor. A greater number of fractures was observed in molars when compared with the number of fractures observed in the other dental groups (p < 0.01). Considering all of the instrument fractures, 71.43% were located in the apical third and 28.57% in the middle third (p < 0.01). One instrument fragment was removed, one bypassed, while in 5 cases, the instrument fragment remained inside the root canal. CONCLUSIONS: The use of Reciproc R25 instruments in root canal retreatments carried out by postgraduate students was associated with a low incidence of fractures.

Microextraction of Reseda luteola-Dyed Wool and Qualitative Analysis of Its Flavones by UHPLC-UV, NMR and MS.

Detailed knowledge on natural dyes is important for agronomy and quality control as well as the fastness, stability, and analysis of dyed textiles. Weld (Reseda luteola L.), which is a source of flavone-based yellow dye, is the focus of this study. One aim was to reduce the required amount of dyed textile to ≤50 µg for a successful chromatographic analysis. The second aim was to unambiguously confirm the identity of all weld flavones. By carrying out the extraction of 50 µg dyed wool with 25 µL of solvent and analysis by reversed-phase UHPLC at 345 nm, reproducible chromatographic fingerprints could be obtained with good signal to noise ratios. Ten baseline separated peaks with relative areas ≥1% were separated in 6 min. Through repeated polyamide column chromatography and prepHPLC, the compounds corresponding with the fingerprint peaks were purified from dried weld. Each was unequivocally identified, including the position and configuration of attached sugars, by means of 1D and 2D NMR and high-resolution MS. Apigenin-4'-O-glucoside and luteolin-4'-O-glucoside were additionally identified as two trace flavones co-eluting with other flavone glucosides, the former for the first time in weld. The microextraction might be extended to other used dye plants, thus reducing the required amount of precious historical textiles.

Factors Associated with Post-Endodontic Treatment Pain Performed by Students in an Endodontic Graduate Program.

Introduction: The aim of this study was to evaluate the possible associations between pre-established clinical variables and manifestation of postoperative pain after endodontic treatments performed by graduate students in endodontics, from June 2016 to December 2017. Methods and Materials: A total of 998 dental patient charts were included in the study. All the patients underwent the same clinical protocol. Possible associations between postoperative pain and clinical variables were investigated, including age, gender, type of tooth, type of treatment, pulpal diagnosis, periradicular diagnosis, instrumentation system used, number of sessions, previous symptom, procedural accident, and endodontic sealer extrusion. Patients were contacted by telephone 24 h and 7 days after treatment completion and were asked about the degree of postoperative pain they had experienced, using a four-level scoring system: 0, no pain; 1, mild pain (no medication was needed); 2, moderate pain (an analgesic or anti-inflammatory was needed); 3, severe pain. Fischer's exact test, Pearson's test, and logistic regression were used for the statistical analysis of the data. A significance level of 0.05 was used. Results: A total of 8.6% of the patients reported having experienced postoperative pain, 50% of which reported mild pain, 47.7%, moderate pain, and 2.3%, severe pain. The only variable significantly associated with postoperative endodontic pain was pre-endodontic treatment symptoms (Pearson's test, P=0.0047). The logistic regression analysis indicated that the association between use of the Reciproc system and sealer extrusion posed a significant risk for postoperative endodontic pain. Conclusion: Based on this retrospective cohort study, the incidence of moderate and severe pain after endodontic treatment was low, and the only variable associated with a higher frequency of patients reporting postoperative endodontic pain was previous pain/symptoms. Therefore, in these cases, pain management methods such as the use of analgesics before treatment or immediately after treatment should be considered.

Symbiotic polydnavirus and venom reveal parasitoid to its hyperparasitoids.

Symbiotic relationships may provide organisms with key innovations that aid in the establishment of new niches. For example, during oviposition, some species of parasitoid wasps, whose larvae develop inside the bodies of other insects, inject polydnaviruses into their hosts. These symbiotic viruses disrupt host immune responses, allowing the parasitoid's progeny to survive. Here we show that symbiotic polydnaviruses also have a downside to the parasitoid's progeny by initiating a multitrophic chain of interactions that reveals the parasitoid larvae to their enemies. These enemies are hyperparasitoids that use the parasitoid progeny as host for their own offspring. We found that the virus and venom injected by the parasitoid during oviposition, but not the parasitoid progeny itself, affected hyperparasitoid attraction toward plant volatiles induced by feeding of parasitized caterpillars. We identified activity of virus-related genes in the caterpillar salivary gland. Moreover, the virus affected the activity of elicitors of salivary origin that induce plant responses to caterpillar feeding. The changes in caterpillar saliva were critical in inducing plant volatiles that are used by hyperparasitoids to locate parasitized caterpillars. Our results show that symbiotic organisms may be key drivers of multitrophic ecological interactions. We anticipate that this phenomenon is widespread in nature, because of the abundance of symbiotic microorganisms across trophic levels in ecological communities. Their role should be more prominently integrated in community ecology to understand organization of natural and managed ecosystems, as well as adaptations of individual organisms that are part of these communities.

Estudo in vitro da espessura de dentina presente nas raízes mesiais de molares inferiores em relação à zona de risco / In vitro study of dentine thickness present in the material roots of lower molars in relation to the risk area

Introdução: o conhecimento da anatomia dental, o uso adequado de instrumentos durante o tratamento endodôntico e técnicas de irrigação do complexo sistema de canais, favorecem a segurança, diminuem o risco de desgastes excessivos na zona de risco e aumentam a probabilidade de maior sucesso na execução dos procedimentos endodônticos. Objetivo: este estudo tem por objetivo avaliar in vitro a espessura da dentina presente nas raízes mesiais de molares inferiores em relação à zona de risco, por meio de cortes transversais a 2 mm da furca. Metodologia: foramselecionados105 molares inferiores humanos adultos, extraídos por razões desconhecidas, hígidos ou portadores de restaurações ou de lesões cariosas que não comprometessem o assoalho da câmara pulpar ou a entrada dos canais radiculares e que possuíssem raízes sem fraturas. Após esta seleção, as raízes mesiais dos espécimes foram marcadas uma a uma 2 mm abaixo da furca e então seccionadas. Os dentes, então preparados, foram fixados com cera utilidade no interior dos blocos de PVC e posicionados para serem fotografados individualmente, com auxílio do microscópio operatório, no aumento de 8X. As imagens foram salvas no computador e depois mensuradas pelo programa Adobe Photshop CC®, onde as medidas foram realizadas da parte interna das raízes MV e ML em direção à furca, a fim de obtermos a menor espessura de dentina presente nesse espaço. Resultados: as medidas encontradas nas raízes MV variaram de 0,18 mm a 1,09 mm, enquanto nas raízes ML variaram de 0,18mm a 0,92mm. Conclusões: não houve diferença significante nas espessuras dentinárias entre as raízes MV e ML.

Introduction: the knowledge of the dental anatomy, the proper use of instruments during endodontic treatment and irrigation techniques of the complex canal system, favor safety, reduce the risk of excessive wear in the risk zone and increase the probability of greater success in the execution of endodontic procedures. Objective: This study aims to evaluate in vitro dentin thickness present in mesial roots of lower molars in relation to the risk zone through transverse cuts at 2 mm furca. Method: we selected 105 adult human lower molars extracted for reasons unknown, healthy or with restorations or carious lesions that did not compromise the floor of the pulp chamber or the entrance of the root canals and that had roots without fractures. Then, the mesial roots of the specimens were marked one by one 2 mm below the furcation and then sectioned. The teeth, then prepared, were fixed with utility wax inside the PVC blocks and positioned to be photographed individually with the help of the operating microscope in the 8X magnification. These images were saved in the computer and then measured through the Adobe Photshop CC® program, where measurements were made from the inside of the MV and ML roots towards the furca in order to obtain the thickness of dentin present in this space. Results: the measurements found in the MV roots ranged from 0.18 mm to 1.09 mm. While in ML roots ranged from 0.18mm to 0.92mm. Conclusions: there was no significant difference in the dentinal thickness between the MV and ML roots.

Influence of Passive Ultrasonic Irrigation on the Removal of Root Canal Filling Material in Straight Root Canals.

OBJECTIVE: This study evaluates the efficacy of passive ultrasonic irrigation (PUI) in removing root canal filling material from endodontically treated teeth after using one of two reciprocating systems, Reciproc (VDW, Munich, Germany) or WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), or one nickel-titanium (NiTi) rotary system, ProTaper Universal Retreatment (Dentsply Maillefer). METHODS: One hundred and twenty straight root canals of extracted human maxillary incisors were instrumented and then obturated. The specimens were divided into six groups (n=20) as follows: Group R, Reciproc R25 instrument without PUI; Group W, WaveOne Primary instrument without PUI; Group PT, ProTaper Universal Retreatment system without PUI; Group R-PUI, Reciproc R25 with PUI; Group W-PUI, WaveOne Primary with PUI and Group PT-PUI, ProTaper Universal Retreatment system with PUI. After removing the filling material, the teeth were cleaved longitudinally and photographed. The total canal space and remaining material were quantified with the aid of an imaging software tool. The Kruskal-Wallis test was used to identify significant differences between the groups. RESULTS: No statistically significant differences (P>0.05) in residual filling material were observed between the groups. CONCLUSION: The use of PUI did not improve the removal of filling material from the root canals, regardless of the previously used instrumentation system.

Efficacy of 2 reciprocating systems compared with a rotary retreatment system for gutta-percha removal.

INTRODUCTION: The maximum removal of root canal filling material is essential for successful endodontic retreatment. The purpose of this study was to assess the efficacy of 2 reciprocating systems (Reciproc [VDW, Munich, Germany] and WaveOne [Dentsply Maillefer, Ballaigues, Switzerland]) compared with a nickel-titanium (NiTi) rotary system (ProTaper Universal Retreatment [Dentsply Maillefer]) in the removal of root canal filling material. METHODS: Sixty root canals of extracted human maxillary incisors were prepared using the NiTi ProTaper rotary system with the complementary use of a #40 K-type file and then obturated. The specimens were divided into 3 groups (n = 20) according to the system used for filling removal: group 1: instrument R25 of the Reciproc system, group 2: primary instrument of the WaveOne system, and group 3: NiTi rotary instruments of the ProTaper Universal Retreatment system. The teeth were cleaved longitudinally and photographed under a dental operating microscope with 5 × magnification. Images were transferred to a computer, and residual filling material was quantified using Image Tool software (University of Texas Health Science Center, San Antonio, TX). Results were compared using 1-way analysis of variance (P < .05). RESULTS: All teeth examined had filling remnants within the canal. No statistically significant difference (P > .05) in residual filling material was observed among the groups, with 4.30% in group 1, 2.98% in group 2, and 3.14% in group 3. CONCLUSIONS: The Reciproc and WaveOne reciprocating systems were as effective as the ProTaper Universal retreatment system for gutta-percha and sealer removal.

Fast chromatographic separation for the quantitation of the main flavone dyes in Reseda luteola (weld).

In the past decades, there has been a renewed interest in the use of natural dye plants for textile dyeing, e.g. Reseda luteola (weld). Its main yellow dye constituents are the flavones luteolin-7,3'-O-diglucoside, luteolin-7-O-glucoside and luteolin. The aim of this work was to develop a simple validated industrially usable quantitative method to assess the flavone content of R. luteola samples. The flavones were overnight extracted from the dried and ground aerial parts of the plant at room temperature via maceration with methanol-water 8:2. Afterwards, they were quantified through internal standardisation against chrysin by RP-HPLC-UV at 345 nm. The efficiency of the one-step extraction was 95%. The limits of detection (LOD) and quantitation (LOQ) were ≤ 1 ng and ≤ 3 ng, respectively, providing ample sensitivity for the purpose. The precision expressed as relative standard deviation of the entire method was <6.5% for the combined content of luteolin-7,3'-O-diglucoside, luteolin-7-O-glucoside and luteolin. The average absolute recovery (accuracy) at three spiking levels was 102% (range: 98-107%) and the relative recovery ranged from 99 to 102%. The separation was initially carried out on a traditional 250 mm × 4.6 mm 5 µm HPLC column (80 min run time, 35.9 mL MeOH). It was then speeded up by the use of a 50 mm × 3.0mm 1.8 µm UHPLC column (5 min run time, 1.4 mL MeCN), while still using a conventional HPLC system. Whereas, the retention times on the UHPLC column were relatively less reproducible, cross-validation showed that the quantitation of luteolin-7,3'-O-diglucoside, luteolin-7-O-glucoside and luteolin was not statistically significantly different, with comparable precision. The method using the UHPLC column is more sensitive. The analytical method described meets the demand for a very small manpower input per sample and uses standard laboratory equipment. Usage of short UHPLC columns opens up interesting possibilities for modernising HPLC-based phytochemical analyses.

Evaluation of the antifouling properties of 3-alyklpyridine compounds.

One of the most promising alternative technologies to antifouling (AF) biocides based on toxic heavy metals lies in the development of natural eco-friendly biocides. The present study evaluates the AF potential of structurally different compounds containing a 3-alkylpyridine moiety. The products, namely poly 3-alkylpyridinium salts, saraine, and haminols, were either extracted or derived from natural sources (the sponges Haliclona sp. and Reniera sarai and the mollusc Haminoea fusari), or obtained by chemical synthesis. All the molecules tested showed generally good anti-settlement activity against larvae of the barnacle Amphibalanus (=Balanus) amphitrite (EC(50) values between 0.19 and 3.61 µg ml(-1) and low toxicity (LC(50) values ranging from 2.04 to over 100 µg ml(-1)) with non-target organisms. For the first time, the AF potential of a synthetic monomeric 3-alkylpyridine was demonstrated, suggesting that chemical synthesis is as a realistic way to produce large amounts of these compounds for future research and development of environmentally-friendly AF biocides.

Evaluation of interference of calcium hydroxide-based intracanal medication in filling root canal systems.

AIM: To evaluate the interference of the intracanal medication Calen® (SSWhite, Sao Paulo, Brazil) on the filling of simulated lateral canals. MATERIALS AND METHODS: Twenty human anterior teeth were used. Before the endodontic filling procedures the access of cavity was made, and after this root canals were made in all the teeth to simulate the presence of lateral canals. After preparation, the teeth were randomly divided into two groups (n=10). In group I, the root canal system was filled directly after chemicalmechanical preparation; in group II, endodontic treatment was performed in multiple sessions, and after preparation the calcium hydroxide-based intracanal medication Calen® was inserted. After the period of 7 days, the root canals were vigorously irrigated and then they were filled. Next, the teeth were radiographed to verify the quality of the filling. RESULTS: The results demonstrated that the teeth treated in a single session, without calcium hydroxide medication, presented 47 canals out of 60 with radiographic evidence of filling, whereas the teeth in which intracanal medication was used, only 07 presented a radiographic image compatible with filling (p < 0.05). CONCLUSION: The use of the calcium hydroxide-based medication Calen made it difficult to obtain a hermetic filling of the root canal system. CLINICAL SIGNIFICANCE: The clinical significance of this work basing on the fact that once the dentist knowing that property obliteration of calcium hydroxide can be taken care when they are used in the presence of lateral canals.

Incidência de flare-ups em tratamentos endodônticos realizados em sessão única e sessão múltipla em dentes necrosados

Introdução: a literatura, atualmente, apresenta muitas controvérsias ao correlacionar a incidência de flare-ups coma abordagem do tratamento endodôntico em sessão única e sessão múltipla. Objetivo: avaliar comparativamente a incidência de flare-ups em 117 pacientes submetidos ao tratamento endodôntico em sessão única e sessão múltipla.Resultados: os resultados apresentados pelos pacientes que foram atendidos em sessão única não apresentaram diferenças estatisticamente significativas com aqueles que foram atendidos em múltiplas sessões. Conclusões: de acordo com esse estudo, concluiu-se que o número de intervenções necessárias para a finalização da terapia endodôntica não tem correlação com a incidência de flare-ups