Rubeanic Acid Research Articles

A facile approach for design of novel semiconducting thiazolo[5,4-d]thiazole-based conjugated polymers in ambient conditions

The design of conjugated polymers with advanced properties is a significant task for the development of organic electronics. At the same time, it is important to pay attention to the methods of their synthesis, excluding toxic and expensive reagents, following the trends in sustainability. In this study, six thiazolothiazole-based conjugated polymers with thiophene, fluorene, phenylene, and benzodithiophene moieties were synthesized and thoroughly characterized. All materials were obtained through a non-catalyzed condensation reaction of carbonyl derivatives with rubeanic acid under ambient conditions. It is shown that the optoelectronic and electrophysical properties of polymers are suitable for their application in organic or hybrid electronic devices. The certain polymers are found to be promising hole-transport interlayer materials in perovskite solar cells, thus featuring the great potential of proposed methods of development of organic semiconductors.

Assessment of 13 essential and toxic trace elements in tumor and peritumoral brain tissues from human glioblastoma.

Trace elements within the brain are important for proper neurological function, but their imbalance has been rarely investigated in glioblastoma. This study enrolled a total of 14 patients with glioblastoma, and the tumor and peritumoral brain tissues were collected while undergoing surgery. The concentrations of Mg, Ca, Cr, Mn, Fe, Co, Cu, Zn, Se, As, Cd, Tl and Pb were determined using a well-evaluated ICP-MS method. The Cu- and Cd-binding proteomes were further analyzed using the anatomic transcriptional atlas from Ivy GAP. Histological evaluation was based on rubeanic acid staining and immunohistochemistry, respectively. The 13 trace element concentrations were obtained, and the highest were Ca, Mn, Fe, Zn and Cu, ranging from a few to dozens of ug/g. Correlation analysis suggested the existence of two intra-correlated clusters: essential metals (Cu-Ca-Zn-Mg) and heavy metals (Pb-As-Cd-Tl-Co-Cr-Mn). Compared to the tumor samples, significantly higher levels of Cu and Cd were observed in the peritumoral region. Further analysis of the Cu- and Cd-binding proteins from the anatomic view suggested that DBH and NOS1 were obviously increased in the leading edge than the central tumor region. Consistent with the above findings, histological evaluation of Cu and DBH further confirmed more copper and DBH expressions in the peritumoral area compared to the tumor core. Trace elements differ in tumor and peritumoral brain zone in glioblastoma, which may associate with tumor angiogenesis.

Ni(II) and Cu(II) coordination polymers with rubeanic acid ligands as promising electrode materials for lithium and potassium batteries

We report the synthesis of Ni(II) and Cu(II) coordination polymers with rubeanic acid ligands and their application as electrode materials in lithium and potassium batteries. Both designed polymers delivered specific discharge capacity of ∼100–106 mAh g−1 and demonstrate stable charge-discharge cycling at 1 A g−1 for at least 300 cycles. Furthermore, Ni-based coordination polymer showed decent performance in potassium batteries providing the specific discharge capacity of 138 mAh g−1 after 400 cycles at 0.5 A g−1. The electrode degradation pathways during the battery cycling were investigated using ex-situ FTIR and XPS spectroscopy.

Toxic Agents in Ruminants Diagnosed in the Pathological Anatomy Service of the UFRRJ, Rio de Janeiro - Brazil

Background: Toxic agents are chemical substances or physical agents that, when interacting with living organisms, cause harmful effects. For animals, toxic products include those intended to combat endo and ectoparasites, rodenticide products, and heavy metals. Minerals and dietary additives, even if essential to the animal, can become toxic agents, among which sodium chloride, copper, urea, and ionophore antibiotics stand out. This study aimed to survey the diagnoses of accidental poisoning in ruminants over 65 years as recorded in the files of the Pathological Anatomy Sector of the Federal Rural University of Rio de Janeiro.Materials, Methods & Results: The diagnoses of poisoning by ticks, rodenticides, heavy metals, macro and micronutrients, and dietary additives in ruminants were made based on the association of epidemiological, clinical, and anatomopathological findings and, in some cases, by histochemical (rubeanic acid and Masson trichrome) and toxicological examinations. A review of data recorded over 65 years identified 372 poisonings in ruminants. Of these, 85.5% (318/372) were in bovine species and 14.5% (54/372) in goats, sheep, and buffaloes. The outbreak of poisoning by organophosphates resulted in the death of 16 cattle that ingested contaminated broken rice and corn. The spraying of this product on the bags was intended to control insects. Intoxication due to excessive administration of abamectin resulted in the intoxication of 16 calves, in two distinct farms. Toxicosis caused by coumarin derivatives resulted in the death of six cattle after accidental ingestion of these rodenticides near the pens. Arsenic poisoning occurred due to ingestion of ant poison, available in bone meal and a mineral salt, through baths with arsenic-based ticks, or in cases later confirmed by toxicological analysis, resulting in the death of 109 cattle. Sodium chloride toxicosis resulted in the death of 10 sheep that became ill in two farms after excessive consumption of salt and private access to water. The diagnosed copper poisoning resulted in the death of 165 ruminants (154 cattle, 10 sheep, and 1 goat). Urea poisoning occurred due to excessive ingestion by 13 cattle and 4 buffaloes, without prior adaptation. Cases of poisoning by ionophore antibiotics occurred in 11 sheep, 18 buffaloes, and 4 cattle. In all cases, the source of exposure was mineral salt and/or feed with an excess of ionophores. The results of the laboratory tests varied according to the type of intoxication.Discussion: Among the means of diagnosing poisoning by toxic agents, minerals, and dietary additives, anamnesis should be detailed and highlighted to present all relevant information. It is the basis for toxicological diagnosis, because it generates information that helps in the definitive elucidation of cases and establishing control and prophylaxis plans, facilitates the prediction of prognosis, and directs the application of appropriate therapy, when possible. In the intoxication diagnoses reported here, the toxicological examination was important in elucidating the toxicosis caused by organophosphates, coumarin derivatives, arsenic, and copper, but the referral for toxicological analysis was previously indicated by a hypothesis generated during the anamnesis. Therefore, anamnesis becomes important yet elusive as toxicological examination leading to diagnosing intoxication.Keywords: toxicology, diagnosis, chemical substance, farm animals.Descritores: toxicologia, diagnóstico, substância química, animais de fazenda.

Attenuation of incident light sources (two flow tubes in one geometrical flow cell assembly: First with eleven sources while the second is covered by six sources) in CFIA for the determination of Copper (II) ion

A highly accurate, simple, sensitive and fast developed method was used for the determination of copper (II) ion using a homemade NAG-ADF-300-2 system with continuous flow injection analysis system. This method is based on reaction between copper (II) ion and rubeanic acid to obtain a black precipitate for the ion-pair complex. Turbidity was measured via the attenuated of incident light by precipitated at 0-180°. Optimum parameters were studied to increase the sensitivity for newly developed methodology of copper (II) ion -rubeanic acid system. The linear range for calibration graph was 1-25 mmol.L-1 for cell A and 1-30 mmol.L-1 for cell B, and LOQ 27.0538 µg /78.5 µL for cell A and 18.5539 µg /78.5 µL for cell B respectively with correlation coefficient (r) 0.9979 for cell A and 0.9992 for cell B, RSD % was lower than 0.5%, (n=8) for the determination of copper (II) ion at concentration 18, 23 mmol.L-1 for cell A and 12, 19 mmol.L-1 for cell B, respectively. A comparison was made between the newly developed method with UV-Spectrophotometric method as a classical method by tow type of statistical analysis for comparison the means and variance from different methods. The comparison of data revealed that long distance chasing photometer (NAG-ADF-300-2) was the choice with excellent extended detection, wide application and more sensitive.

Newly developed method for the determination of sitagliptin phosphate using rubeanic acid as a precipitating agent via the use of ISNAG continues flow fluorimeter

A new, a simple, sensitive and fast developed method for the estimation of sitagliptin phosphate in pure and pharmaceutical drugs (tablet). This method based on the reaction between sitagliptin phosphate and rubeanic acid to form reddish-black ppt, using ISNAG-Fluorimeter analyzer via the measure of diverged light at 90° from radiation source which is used a range of high intensity ultraviolet 184.9 nm & 253.7 nm by low-pressure mercury lamp while detector cell can detect at 410-1150 nm. The resultant of diverged light by an interaction between incident photons and precipitated particles giving rise to a longer wavelength that the detector can detected. Chemical and physical parameters were studied and optimized. The calibration graph was linear in the range of (0.03-13 ) mmol.L−1 , with correlation coefficient ( r )= 0.9881 ,linearity percentage r2%= 97.64 , L.O.D = 0.7848µg/sample and RSD lower than 0.6 % for (3&7 ) mmol.L−1 ( eight replicates) concentration of sitagliptin phosphate. This method was successfully applied for the determination of sitagliptin phosphate in two different companies of pharmaceutical drugs. A comparison was made between the newly developed method analysis with the classical method (UV-spectrophotometer by measuring of absorbance ) using standard addition method via the use of t-test, it was noticed that there was no significant difference between two methods at %95 confidence level.

Histochemistry based confirmation of the diagnosis of Copper Sulphate Poisoning: Case-Series

The suspected suicidal death cases from copper sulphate poisoning is not uncommon in West Bengal as well as in some other parts of India. But due to extreme delay in laboratory confirmation report from Forensic Science Laboratory (FSL) regarding presence of copper in toxic doses in the preserved samples the final opinion regarding cause of death in medico legal autopsy cases is kept pending. The histochemical method of rubeonic (rubeanic) acid staining of hepatocytes to determine the presence of copper in toxic level there, can be used as an alternative method to confirm copper sulphate poisoning. In this study, slides of liver biopsy from twelve autopsy cases of suspected copper sulphate poisoning are stained with rubeonic acid. All of them showed positive results indicating confirmation of copper sulphate poisoning. Hence, this method can be adopted as an alternative to toxicological analysis of copper sulphate poisoning.

Cerebral Pathology in Hepatolenticular Degeneration (Wilson Disease)

Introduction. Hepatolenticular degeneration (HLD), or Wilson disease, is one of the severe progressive hereditary disorders of the nervous system. A number of questions regarding its pathogenesis and pathology are the subject of in-depth research. The aim of the study was to examine cerebral pathology and determine the leading factors in its pathogenesis in the autopsy cases of HLD. Materials and methods. A postmortem study was carried out in 15 deceased patients (14–35 years old) with HLD. In all cases, clinical diagnosis was based on the characteristic signs of CNS and liver damage, presence of the Kayser–Fleischer corneal ring, and specific biochemical abnormalities in copper and protein metabolism. A set of histological, neurohistological, and histochemical staining methods was used, including the histochemical study of copper after the fixation of brain slices in rubeanic acid. Results. In all cases, severe microcirculatory changes were found in the brain, characteristic of the angiotoxic component of HLD, with impaired vessel permeability and the development of persistent edema and spongiform changes in brain tissue. Changes were more often found in the basal nuclei area, as well as in the white matter of the cerebral hemispheres, cerebellum, and pons. The cytotoxic component of HLD was evident in the same regions of the brain, represented by degenerative changes in astrocytes and neurons, often ending in their death. The most frequent form of pathology was the appearance of Alzheimer type II glia with ‘naked’ nuclei, and much less frequently, Alzheimer type I glia. The histochemical study showed deposits of copper granules in the endothelial cells of microvessels, Alzheimer type II glia, and neurons – predominantly in the globus pallidus and the caudate nucleus. Conclusion. A set of pathogenic factors plays an essential role in the pathogenesis of the brain damage in HLD: the toxic effect of copper on the brain, the damage to and impaired permeability of the blood-brain barrier, severe metabolic disturbances caused by liver failure, and brain hypoxia.

Acetylcholinesterase staining for the pathological diagnosis of Hirschsprung's disease.

Hirschsprung's disease (HD) is a congenital disease manifesting various degrees of functional bowel obstruction caused by the absence of enteric ganglion cells, which are usually absent in the colonic segment of the HD patient. Because the aganglionic segment of HD always includes the rectum, pathological diagnosis can be made using a rectal sample. HD should be diagnosed as early as possible because serious complications, such as acute enterocolitis or toxic megacolon, can develop without a definitive diagnosis and appropriate treatment. In the mid-1900s, HD was diagnosed by HE staining of specimens obtained by full-thickness biopsy. Since then, the combination of rectal mucosal biopsy and rubeanic acid-amplificated AChE staining has been brought about by the following milestones: the discovery that the submucosal plexus and the intermuscular plexus had the same level of nerve migration; the findings of research on acetylcholine (ACh) and acetylcholinesterase (AChE) in the intestinal tract; and the establishment of a rubeanic acid amplification method. Consequently, the diagnostic rate of HD improved dramatically in the 1980s. This review outlines the history of diagnostic methods for HD, the roles of ACh and AChE in the intestine, and the method of AChE staining.

Hemolytic Crisis in a Dog with Copper-Associated Chronic Hepatitis

Background: Copper is an essential micronutrient for the body to function properly. However, although it is a vital element, an excess of copper in the body is extremely toxic. Copper toxicity has been reported mainly in sheep. In dogs, clinicopathological signs of toxicity are characterized by chronic liver failure. This means that the hemolytic crisis so common in sheep is a condition rarely associated with toxicity in dogs, so there are very few descriptions of this condition in the veterinary literature. The purpose of this report is to describe a case of hemolytic crisis in a dog with copper-associated chronic hepatitis.Case: A medium-sized 6-year-old bitch was brought to the Veterinary Hospital of the Federal University of Santa Maria, with clinical presentation of apathy, anorexia and red urine. A physical examination revealed mildly jaundiced mucosa and dark brown urine. A urinalysis indicated the presence of protein, bilirubin and occult blood. The blood count revealed hypochromic macrocytic anemia, leukocytosis due to left shift neutrophilia and thrombocytopenia. Serum biochemistry showed elevated levels of alanine aminotransferase and alkaline phosphatase. The animal was given a blood transfusion due to the severity of her anemia, but her clinical condition worsened and she died, whereupon her body was sent for necropsy. This necropsy revealed conspicuous signs of jaundice, splenomegaly and altered liver and kidney color. The liver was brownish, with its natural surface firm and slightly irregular. The kidneys were diffusely blackened. The urine was dark brown. Fragments of different organs were collected, fixed in 10% buffered formalin solution, routinely processed for histopathology and stained with hematoxylin and eosin. A histological dissection of the liver showed the hepatic lobes dissected by fibrosis, forming islands of hepatocytes and numerous lymphocytes and plasmocytes. Brown granular pigment was observed in periportal hepatocytes. Perls Prussian blue and rubeanic acid staining techniques were performed to characterize this pigment. Most of the pigment reacted strongly to rubeanic acid and but not to Perls’ Prussian blue, thus characterizing it as copper. Random hepatic necrosis was visible. The kidneys contained hemoglobin and necrotic epithelial cells obstructing the renal tubules. Based on the clinical and anatomopathological aspects, a diagnosis of hemolytic crisis due to copper-associated chronic hepatitis was established.Discussion: The most accepted mechanism to explain the occurrence of hemolysis is that copper long stored in hepatocytes is massively released into the bloodstream due to some stressful condition. When too much copper circulates in the bloodstream it inhibits enzymes that act on the energy metabolism of red blood cells, thereby lowering the synthesis of energy and nucleotides needed for glutathione activity, and causing hemoglobin to transform into methemoglobin. In the case reported here, copper toxicosis presumably originated from the animal’s diet since, according to the literature, the periportal distribution of copper revealed during histology suggests that the event resulted from excessive copper intake or was secondary to previous cholestatic liver injury. This paper describes a case of hemolytic crisis in a dog with copper-associated chronic hepatitis and, emphasizes the importance of including copper toxicity as a differential diagnosis for dogs presenting hemolytic crisis, in order to assist veterinarians in managing their patients.

DFT study of [Pt(Cl)2L] complex (L = rubeanic acid) and its derived compounds with DNA purine bases

In this study, we present a systematic computational investigation on the electronic properties of cisplatin (cis-[Pt(Cl)2(NH3)2] (CP) and complex [Pt(Cl)2L] (1) (L = rubeanic acid) employing all-electron density functional theory. In detail, we analyzed essential molecular properties such as geometrical parameters, ionization energies, electron affinity, highest occupied molecular orbital, and lowest unoccupied molecular orbital energies. Concerning CP, molecule 1 exhibited improved lipophilicity and a pronounced electrophilic property. Furthermore, to investigate and compare the DNA binding capability between CP and molecule 1, we extended the investigation to the guanine and adenine derived complexes, respectively. Complexes of molecule 1 with the adenine and guanine bases followed a similar trend of stability found for CP systems, with the highest affinity found for guanine complexes. Altogether, molecule 1 displayed promising physicochemical and druglikeness features to serve as a starting point for developing a drug-like enough that could be therapeutically useful.

Copper tolerance of the soft-rot fungus Phialophora malorum grown in-vitro revealed by microscopy and global protein expression

In this study, we used proteomics in conjunction with microscopy to study differences in the proteome and hyphal morphology of the copper tolerant soft rot fungus Phialophora malorum grown in media containing 0.064, 0.64% Cu as CuSO4. Unique proteins were found in the control and the copper-treated (0.064% CuSO4) samples. Of five unique proteins found in the 0.064% CuSO4 treated cultures, ATP synthase subunit alpha is considered to play an important role in copper tolerance as it is involved in the biosynthesis of fatty acids and steroids and may relate to morphological changes associated with hyphal cell walls of the fungus when grown in the presence of copper. ICP-AES analyses showed total mycelial Cu to increase with media Cu with 5246- and 16535 μg Cu/g dry wt mycelia respectively found in 0.064 and 0.64% Cu-cultures after 6 weeks growth. Rubeanic acid staining of 0.064% mycelia showed Cu bound in intracellular bodies while most Cu was found as extracellular precipitates on the surfaces of hyphae in 0.64% Cu. SEM showed hyphal surfaces enrobed in fibrillar polysaccharides to which Cu was bound.

Exchange Capacity of Polysiloxane Ion Exchangers Modified with Dithiooxamide Groups with Respect to Silver(I), Platinum(IV), and Palladium(II)

A polysiloxane with attached groups of rubeanic acid is proposed for the extraction of silver(I), platinum(IV) and palladium(II) from dilute aqueous systems. The sorbent is synthesized for the first time via modern sol–gel technology and has a high degree of surface modification; the concentration of the attached dithiooxamide groups is 0.90 mmol/g. Isotherms of the sorption of silver(I), platinum(IV), and palladium(II) from individual solutions are constructed. The curves are mathematically processed with the Langmuir, Freundlich, Redlich–Peterson, Langmuir–Freundlich, and Toth equations, so exchange capacity values are determined for the modified polysiloxane. The sorbent has good capacitive characteristics and can be used to accumulate large amounts of noble metal ions.

SORPTION-ATOMIC-ABSORPTION DETERMINATION OF PALLADIUM (II) IN AQUEOUS SOLUTIONS USING DITHIOOXAMIDATED POLYSILOXANE

Polysiloxane modified with groups of rubeanic acid (dithiooxamidated polysiloxane (DTOAP)) is proposed for extraction of palladium (II) from the solution against the background of the accompanying components. Sorbent was synthesized for the first time at the Institute of Organic Synthesis (Ural Branch of the Russian Academy of Sciences) using «sol-gel» technique. Sorption of palladium (II) was carried out under competitive conditions with 9 possible accompanying metals ions present. Palladium (II) is quantitatively and selectively recovered under static conditions with DTOAP from a solution containing transition metal ions, including platinum (IV). It takes 30 minutes for complete extraction of palladium (II). Reversible character of palladium (II) sorption is shown. Quantitative desorption of metal ion from the sorbent surface is possible using a 1% solution of thiourea in 1 M hydrochloric acid. Sorption under dynamic conditions provides separation of palladium (II) from platinum (IV) and concomitant ions of base metals. DTOAP provides quantitative extraction of palladium (II) in an amount up to 0.2 mmol/g. The developed method of the atomic-absorption determination of palladium (II) with a preliminary concentration on a modified polysiloxane was tested in analysis of model and industrial solutions with a high saline background.

Sodium hypochlorite penetration into dentinal tubules after manual dynamic agitation and ultrasonic activation: a histochemical evaluation.

The aim of this study was to compare the effects of Manual Dynamic Agitation and Passive Ultrasonic Irrigation on sodium hypochlorite (NaOCl) penetration into dentinal tubules using its bleaching ability. Thirty-four single-rooted teeth with round-shaped root canals were distributed in two homogeneous groups and one control group, characterized by different NaOCl activation systems: Manual Dynamic Agitation and Passive Ultrasonic Irrigation. After instrumentation, all root canals were stained with 10% copper sulphate solution followed by 1% rubeanic acid alcohol solution under vacuum. Final irrigation was performed with 5mL of 5.25% NaOCl solution for 1min and activated with Manual Dynamic Agitation or Passive Ultrasonic Irrigation for another 1min depending on the treatment group. The teeth were transversely sectioned at the middle portion of the apical, middle, and coronal thirds and observed under light microscope. NaOCl solution penetration was evaluated by measuring the percentage of bleached circumference of the root canal relative to the stained circumference, bleached areas, mean, and maximum penetration depth. No differences in the evaluated parameters were observed between groups (p > 0.05). Within groups, an increase of values was recorded from apical to coronal direction as for percentage of staining, percentage of bleaching and bleached area. NaOCl penetration into dentinal tubules did not significantly vary among the three levels. No significant differences in penetration of sodium hypochlorite into dentinal tubules when activated by means of Manual Dynamic Agitation or Passive Ultrasonic Irrigation were observed in the apical, middle, and coronal thirds of teeth with single straight round root canals.

MWCNTs@Rubeanic acid nanosensor for ultra sensitive quantification of bismuth in groundwater and soil

Voltammetric determination of bismuth was made using a carbon paste electrode modified with carbon nanotube-encapsulated rubeanic acid. The anodic stripping voltammetry on the MWCNTs@Rubeanic acid composite electrode exhibited well-defined, sharp and undistorted peaks with a favorable resolution for bismuth. Comparing a non-encapsulated MWCNTs composite electrode with an in-situ capsulated MWCNTs@Rubeanic electrode, the MWCNTs@Rubeanic composite electrode exhibited superior performance due to its complexation with Bi ion. The limit of detection of the sensor was 0.8 ng/mL.

Impact of ionophore monensin on performance and Cu uptake in earthworm Eisenia andrei exposed to copper-contaminated soil

Exposure of beneficial soil organisms to chemical mixtures is of great concern and can result in unexpected deleterious consequences. We investigated the effects of concurrent soil contamination with monensin, a veterinary pharmaceutical and feed additive, and copper, on earthworm copper uptake and reproductive success. The animals were exposed for 14 or 28 days to both substances and the results showed that the Cu body burden of earthworms increases in the presence of monensin. The harmful effects of Cu on earthworm cocoon production were considerably higher when monensin was also present in the soil. To localise the copper in earthworm tissues, histological staining was performed using two different dyes (rubeanic acid and 5-4-(p-dimethylaminobenzylidene)-rhodanine). Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to quantify the Cu levels in the tissues. Cu was found predominantly in the gut wall. The Cu content in the body wall was at least ten times lower compared to the gut, but was proportional to the level of soil contamination. Concurrent soil contamination with monensin and copper resulted in higher earthworm Cu levels and in decreased reproductive success of these important soil decomposers.

Visualisation of latent fingermarks on polymer banknotes using copper vacuum metal deposition: A preliminary study

The UK's recent move to polymer banknotes has seen some of the currently used fingermark enhancement techniques for currency potentially become redundant, due to the surface characteristics of the polymer substrates. Possessing a non-porous surface with some semi-porous properties, alternate processes are required for polymer banknotes. This preliminary investigation explored the recovery of fingermarks from polymer notes via vacuum metal deposition using elemental copper. The study successfully demonstrated that fresh latent fingermarks, from an individual donor, could be clearly developed and imaged in the near infrared. By varying the deposition thickness of the copper, the contrast between the fingermark minutiae and the substrate could be readily optimised. Where the deposition thickness was thin enough to be visually indistinguishable, forensic gelatin lifters could be used to lift the fingermarks. These lifts could then be treated with rubeanic acid to produce a visually distinguishable mark. The technique has shown enough promise that it could be effectively utilised on other semi- and non-porous substrates.

Sodium hypochlorite solution penetration into human dentine: a histochemical evaluation.

The aim of this study was to evaluate exvivo the penetration depth of sodium hypochlorite solutions, with and without surfactants, into human dentine using a histochemical stain and the bleaching ability of NaOCl. Extracted maxillary central incisors were decoronated and their root canals were shaped to a size 30, .07 taper. Dentinal tubules were stained with 10% copper sulphate solution followed by a 1% rubeanic acid alcohol solution under vacuum. Specimens were irrigated with 5 mL of Niclor 5 (5.25% NaOCl solution) or 5 mL of Hypoclean (5.25% NaOCl solution + surfactants) according to the corresponding treatment group, for 2min. A transverse section was obtained in the middle portion of the apical, middle and coronal thirds of each tooth. Under microscopic examination, irrigant penetration was evaluated by measuring the following: the bleached circumference of the root canal with respect to the stained circumference; bleached areas, mean and maximum penetration depth. For statistical analysis, Pearson's chi-squared test and one-way anova were used. Only 30% of dentine tubules in the apical portions were stained; therefore, these were excluded from further comparisons. In the middle and coronal thirds, the average bleached circumference of the root canal was 80-99% of the stained circumference and the bleached area was 73757-135107μm2 . The average penetration depth ranged from 39 to 62μm and maximum penetration from 74 to 131μm. For all reported results, no differences within and between groups were observed (P=1). No differences in penetration of irrigants with and without surfactants into dentinal tubules were observed in the middle and coronal thirds of incisor teeth.

Highly luminescent N, S- Co-doped carbon dots and their direct use as mercury(II) sensor

Heteroatom doping has been proven as an efficient way to improve the fluorescent efficiency of carbon dots. Co-doping with heteroatoms may introduce more active sites to carbon dots, which would broaden applications of CDs in sensing. In this work, highly luminescent nitrogen and sulfur co-doped carbon dots (NSCDs) were synthesized through a facile one-step microwave assisted method by using citric acid and rubeanic acid as carbon, nitrogen, and sulfur sources. The well-isolated NSCDs not only exhibit an enhanced fluorescent efficiency with a relatively high quantum yield up to 17.6%, but also show potential use as a multi-sensing platform based on their fluorescence “on-off-on” and color changing behaviors. The NSCDs can be directly used for the selective determination of mercury cations without any functionalization. The detection limit is approximately calculated as 0.18 μM and linear range is 0–20 μM. The sensing mechanism is proposed as coordination reaction induced by oligomers upon the carbon core. Furthermore, in the presence of cyanide anions, the fluorescence shows linear recovery associated with the concentration of cyanide, indicating its potential usage for the detection of cyanide ion. The optimized pH range for such fluorescence “on-off-on” sensing system is investigated as pH 6–8, suggesting potential applications in bio-sensing and imaging area. In addition, by adding hydrosulfide anion to NSCDs@Hg2+ complex, a notable color change could be clearly observed due to the formation of fuscous HgS. In application, a handy test paper for direct and rapid detection of Hg2+ is manufactured for the evaluation of usage of NSCDs in the real circumstance.