Luminescent Pyrene-based Schiff base Receptor for Hazardous Mercury(II) Detection Demonstrated by Cell Imaging and Test Strip

Qualitative and quantitative analysis of mercury at concentration levels as low as parts per billion (ppb) is a basic and practical concern. The vast majority of research in this field has centered on the development of potent chemosensor to monitor mercuric (Hg²⁺) ions. Mercury exists in three oxidation states, + 2, + 1 and 0, all of which are highly poisonous. In this study, (N¹E,N²E)-N¹,N²-bis(pyrene-1-ylmethylene)benzene-1,2-diamine (PAPM), a novel photoluminescent sensor based on pyrene platform was synthesized. Over the tested metal ions (Cd²⁺, Co²⁺, Cu²⁺, Mg²⁺, Mn²⁺, Ni²⁺, K⁺, Na⁺, Zn²⁺, Sr²⁺, Pb²⁺, Al³⁺, Cr³⁺ and Fe³⁺) the sensor responds only to Hg²⁺ by showing high selectivity and sensitivity. After treatment with mercuric ions at room temperature, the luminescence intensity of probe was quenched at 456 nm. The quenching of fluorescence intensity of probe upon addition of mercury is due to the effect of "turn-off" chelation enhanced quenching (CHEQ) by the formation of 1:1 complex. The ESI-MS spectrum and the Job's experimental results confirm the formation of 1:1 complex between PAPM and Hg²⁺. The detection limit and association constant of sensor for mercury is computed using fluorescence titration data and were found to be 9.0 × 10^-8 M and 1.29 × 10⁵ M^-1 respectively. The practical application of sensor towards recognition of mercury(II) ions was explored through economically viable test strips and also using cell imaging studies.

Copper(i) complexes with quinolone appended 1,8-naphthalimide conjugates: structural characterization, DNA and protein binding and cytotoxicity studies

Cytotoxicity, cellular uptake of copper(i) complexes containing 1,8-naphthalimide conjugates have been investigated.

Synthesis, structural characterization, protein binding, DNA cleavage and anticancer activity of fluorophore labelled copper(ii) complexes based on 1,8-naphthalimide conjugates

The synthesized copper complexes have good anticancer activity and induce an apoptotic mode of cell death.

Synthesis, structural characterization and biological properties of cyclometalated iridium(iii) complexes containing [1,2,5]-thiadiazolo-[3,4-f]-[1,10]-phenanthroline

The iridium(iii) complexes have been structurally characterised and their interaction with DNA, cytotoxicity and cellular uptake have been investigated.

Highly enantioselective epoxidation of olefins by H2O2 catalyzed by a non-heme Fe(ii) catalyst of a chiral tetradentate ligand

A new chiral Fe(ii)-complex mediates the asymmetric epoxidation of prochiral olefins with good enantioselectivity.

A phosphate-targeted dinuclear Cu(II) complex combining major groove binding and oxidative DNA cleavage

Free radical generation is an inevitable consequence of aerobic existence and is implicated in a wide variety of pathological conditions including cancer, cardiovascular disease, ageing and neurodegenerative disorder. Free radicals can, however, be used to our advantage since their production is catalysed by synthetic inorganic molecules-termed artificial metallonucleases-that cut DNA strands by oxidative cleavage reactions. Here, we report the rational design and DNA binding interactions of a novel di-Cu2+ artificial metallonuclease [Cu2(tetra-(2-pyridyl)-NMe-naphthalene)Cl4] (Cu2TPNap). Cu2TPNap is a high-affinity binder of duplex DNA with an apparent binding constant (Kapp) of 107 M(bp)-1. The agent binds non-intercalatively in the major groove causing condensation and G-C specific destabilization. Artificial metallonuclease activity occurs in the absence of exogenous reductant, is dependent on superoxide and hydrogen peroxide, and gives rise to single strand DNA breaks. Pre-associative molecular docking studies with the 8-mer d(GGGGCCCC)2, a model for poly[d(G-C)2], identified selective major groove incorporation of the complex with ancillary Cu2+-phosphate backbone binding. Molecular mechanics methods then showed the d(GGGGCCCC)2 adduct to relax about the complex and this interaction is supported by UV melting experiments where poly[d(G-C)2] is selectively destabilized.

Synthesis, crystal structure and biological properties of a cis-dichloridobis(diimine)copper(II) complex

The mechanisms of interaction of inorganic complexes with DNA are important in the design and development of new metal-based drug molecules. The limitations of cis-platin have encouraged the design and development of new metal-based target-specific anticancer drugs having reduced side effects. The complex cis-dichloridobis(1,2,5-thiadiazolo[3,4-f][1,10]phenanthroline-κ²N¹,N¹⁰)copper(II), [CuCl₂(C₁₂H₆N₄S)₂], has been synthesized and characterized. The complex crystallizes in the monoclinic space group C2/c. The covalent binding of the complex with DNA was studied by absorption spectroscopy. The anticancer activity of the complex on the Human Lung Carcinoma (A549) cell line was investigated by MTT assay. The complex exhibits higher toxicity than cis-platin and induces an apoptotic mode of cell death.

Water mediated proton conductance in a hydrogen-bonded Ni(ii)-bipyridine-glycoluril chloride self-assembled framework

Proton conducting properties have been investigated in a new Ni(ii)-based hydrogen-bonded porous framework synthesized using bipyridine-glycoluril (BPG) tecton.

Phosphorescent cyclometalated iridium(iii) complexes: synthesis, photophysics, DNA interaction, cellular internalization, and cytotoxic activity

Phosphorescent cyclometalated quinoline-appended iridium(iii) complexes undergo rapid cellular internalization and accumulate throughout the cell.

A fluorophore-labelled copper complex: crystal structure, hybrid cyclic water-perchlorate cluster and biological properties

A fluorophore-labelled copper(II) complex, aquabis(dimethylformamide-κO)(perchlorato-κO)[2-(quinolin-2-yl)-1,3-oxazolo[4,5-f][1,10]phenanthroline]copper(II) perchlorate monohydrate, [Cu(ClO₄)(C₂₂H₁₂N₄O)(C₃H₇NO)₂(H₂O)]ClO₄·H₂O, has been synthesized and characterized. A cyclic hydrogen-bonded water-perchlorate anionic cluster, i.e. [(ClO₄)₂(H₂O)₂]^2-, has been identified within the structure. Each cyclic anionic cluster unit is interconnected by hydrogen bonding to the cation. The cations join into an infinite hydrogen-bonded chain running in the [010] direction. Furthermore, interaction of the complex with calf-thymus DNA (CT-DNA) and cellular localization within the cells was explored. Spectroscopic studies indicate that the compound has a good affinity for DNA and stains the nucleus of the cells.

Efficient DNA condensation by ruthenium(ii) polypyridyl complexes containing triptycenyl functionalized 1,10-phenanthroline

A series of luminescent ruthenium(ii) polypyridyl complexes containing an extended aromatic moiety derived from triptycene and 1,10-phenanthroline were synthesized and their photophysical, theoretical, and biological properties were investigated.

Nonheme Fe(IV) Oxo Complexes of Two New Pentadentate Ligands and Their Hydrogen-Atom and Oxygen-Atom Transfer Reactions

Two new pentadentate {N5} donor ligands based on the N4Py (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) framework have been synthesized, viz. [N-(1-methyl-2-benzimidazolyl)methyl-N-(2-pyridyl)methyl-N-(bis-2-pyridyl methyl)amine] (L(1)) and [N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L(2)), where one or two pyridyl arms of N4Py have been replaced by corresponding (N-methyl)benzimidazolyl-containing arms. The complexes [Fe(II)(CH3CN)(L)](2+) (L = L(1) (1); L(2) (2)) were synthesized, and reaction of these ferrous complexes with iodosylbenzene led to the formation of the ferryl complexes [Fe(IV)(O)(L)](2+) (L = L(1) (3); L(2) (4)), which were characterized by UV-vis spectroscopy, high resolution mass spectrometry, and Mössbauer spectroscopy. Complexes 3 and 4 are relatively stable with half-lives at room temperature of 40 h (L = L(1)) and 2.5 h (L = L(2)). The redox potentials of 1 and 2, as well as the visible spectra of 3 and 4, indicate that the ligand field weakens as ligand pyridyl substituents are progressively substituted by (N-methyl)benzimidazolyl moieties. The reactivities of 3 and 4 in hydrogen-atom transfer (HAT) and oxygen-atom transfer (OAT) reactions show that both complexes exhibit enhanced reactivities when compared to the analogous N4Py complex ([Fe(IV)(O)(N4Py)](2+)), and that the normalized HAT rates increase by approximately 1 order of magnitude for each replacement of a pyridyl moiety; i.e., [Fe(IV)(O)(L(2))](2+) exhibits the highest rates. The second-order HAT rate constants can be directly related to the substrate C-H bond dissociation energies. Computational modeling of the HAT reactions indicates that the reaction proceeds via a high spin transition state.

Supramolecular architecture and photophysical and biological properties of ruthenium(ii) polypyridyl complexes

A two-dimensional cyclic hybrid water–chloride anionic network has been structurally characterized in a metal–organic matrix. DNA interactions and the cytotoxicity of ruthenium(ii) complexes have been studied.

Oral health status of Tibetan and local school children of Kushalnagar, Mysore district, India: a comparative study

The presence of migrants culturally different from inhabitants of the host country is now a widespread phenomenon. It is known that dietary habits and oral hygiene practices vary from country to country, which in turn has a profound effect on oral health.

OBJECTIVES

To assess and compare the oral health status of Tibetan school children and local school children of Kushalnagar (Bylakuppe).

STUDY DESIGN

A survey was conducted at Kushalnagar (Bylakuppe), in Mysore district, India to assess the oral health status of Tibetan school children (n = 300) and local school children (n = 300) and compared using World Health Organization oral health proforma (1997).

RESULTS

The proportional values are compared using chi-square test and the mean values are compared using Student's t-test. Statistically significant results were obtained for soft tissue lesions, dental caries, malocclusion, and treatment needs. However, results were not significant when gingivitis was compared in the two populations.

CONCLUSIONS

Tibetan school children showed higher prevalence of Angular cheilitis, gingival bleeding, dental caries experience, malocclusion, and treatment needs in comparison with non-Tibetans. Among the Tibetan school children, the requirement for two or more surface filling was more.

Evaluation of resistance of teeth subjected to fracture after endodontic treatment using different root canal sealers: an in vitro study

AIMS

The aim of this study was to compare the ex-vivo effects of different root canal sealers on the fracture resistance of endodontically treated teeth.

MATERIALS AND METHODS

Seventy-five freshly extracted human mandibular premolars were used for the study. The length was standardized to 14 mm and all the teeth were biomechanically prepared and divided into five different groups based on the type of root canal sealers used. Group I:- Roeko seal + gutta percha, Group II: AH plus ® root canal sealer + gutta percha, Group III: PULPDENT root canal sealer + gutta percha, Group IV: Zinc oxide-eugenol sealer + gutta percha, Group V: Control (unobturated teeth). The teeth were embedded in acrylic resin blocks and compressive strengths were measured using universal testing machine (Instron).

STATISTICAL ANALYSIS USED

One-way ANOVA, unpaired t- test.

RESULTS

Data obtained were statistically evaluated using one-way ANOVA and unpaired t-test. All groups showed a statistically significant result (P < 0.05). Teeth obturated with Group I and Group II showed higher resistance to fracture than teeth obturated with other three Groups. It was seen that the teeth obturated with group III showed a better fracture resistance than Group IV and there was no statistical significance found between Group and Group V.

CONCLUSIONS

From this study, it has been concluded that both the resin based sealers that were used in this study were equally effective compared to that of the zinc oxide-based sealers and the control group. However, no significant results were obtained when the comparison was made between zinc oxide-eugenol and gutta-percha and the control group.

Evaluation of resistance of teeth subjected to fracture after endodontic treatment using different root canal sealers: an in vitro study

AIMS

The aim of this study was to compare the ex-vivo effects of different root canal sealers on the fracture resistance of endodontically treated teeth.

MATERIALS AND METHODS

Seventy-five freshly extracted human mandibular premolars were used for the study. The length was standardized to 14 mm and all the teeth were biomechanically prepared and divided into five different groups based on the type of root canal sealers used. Group I:- Roeko seal + gutta percha, Group II: AH plus ® root canal sealer + gutta percha, Group III: PULPDENT root canal sealer + gutta percha, Group IV: Zinc oxide-eugenol sealer + gutta percha, Group V: Control (unobturated teeth). The teeth were embedded in acrylic resin blocks and compressive strengths were measured using universal testing machine (Instron).

STATISTICAL ANALYSIS USED

One-way ANOVA, unpaired t- test.

RESULTS

Data obtained were statistically evaluated using one-way ANOVA and unpaired t-test. All groups showed a statistically significant result (P < 0.05). Teeth obturated with Group I and Group II showed higher resistance to fracture than teeth obturated with other three Groups. It was seen that the teeth obturated with group III showed a better fracture resistance than Group IV and there was no statistical significance found between Group and Group V.

CONCLUSIONS

From this study, it has been concluded that both the resin based sealers that were used in this study were equally effective compared to that of the zinc oxide-based sealers and the control group. However, no significant results were obtained when the comparison was made between zinc oxide-eugenol and gutta-percha and the control group.

Effect of fluorides from various restorative materials on remineralization of adjacent tooth: an in vitro study

The aim of the study was to evaluate the extent of surface zone remineralization and the effect of fluoride at the inter-proximal adjacent tooth surface, using restorative materials FusionAlloy, Ketac-Fil and Heliomolar. Ninety extracted molar teeth were used of which 45 were placed in artificial caries for 10 weeks. The remaining 45 teeth were filled with the respective restorative materials, mounted with the artificial carious teeth in proximal contact with plaster and placed in artificial saliva for a period of 28 days. Finally, sectioning of artificially carious teeth was done mesio-distally and observed under the optical microscope and scanning electron microscope. Comparison among the groups was done by one-way analysis of variance [ANOVA] and Fischer's F test. Intercomparison between the groups was done by using Dunnett's t-test. Results obtained from transmitted electron microscopic and scanning electron microscopic observations were almost similar with the Ketac-Fil and Heliomolar showing better results in surface zone remineralization compared to FusionAlloy. Also, Ketac-Fil is a good material in releasing fluoride to remineralize enamel when compared to Heliomolar and FusionAlloy. Thus, it can be used mainly in class II cavity restorations of primary and permanent dentitions due to the potential ability of fluoride containing glass ionomer cements and composite resins to remineralize incipient carious lesions on adjacent teeth.

Incontinentia pigmenti

Incontinentia pigmenti or Bloch-Sulzberger syndrome, is a rare X linked dominant disorder with characteristic skin, hair, eye, dental and neurological abnormalities commonly affecting females. This article reports the clinical features and management of a 11 year old girl diagnosed with Incontinentia pigmenti.

Disruption of DMD and deletion of ACSL4 causing developmental delay, hypotonia, and multiple congenital anomalies

We have studied a male patient with significant developmental delay, growth failure, hypotonia, girdle weakness, microcephaly, and multiple congenital anomalies including atrial (ASD) and ventricular (VSD) septal defects. Detailed cytogenetic and molecular analyses revealed three de novo X chromosome aberrations and a karyotype 46,Y,der(X)inv(X) (p11.4q11.2)inv(X)(q11.2q21.32 approximately q22.2)del(X)(q22.3q22.3) was determined. The three X chromosome aberrations in the patient include: a pericentric inversion (inv 1) that disrupted the Duchenne muscular dystrophy (DMD) gene, dystrophin, at Xp11.4; an Xq11.2q21.32 approximately q22.2 paracentric inversion (inv 2) putatively affecting no genes; and an interstitial deletion at Xq22.3 that results in functional nullisomy of several known genes, including a gene previously associated with X-linked nonsyndromic mental retardation, acyl-CoA synthetase long chain family member 4 (ACSL4). These findings suggest that the disruption of DMD and the absence of ACSL4 in the patient are responsible for neuromuscular disease and cognitive impairment.

Estimation of salivary bacteria capable of inhibiting and stimulating Streptococcus mutans and its correlation to dental caries and untreated carious teeth

Bacteriocins are bacteriocidal proteinaceous molecules produced by the Gram-positive bacteria not active against the produced strain. Many investigations have revealed that certain bacteria using antibacterial or the inhibitory substance inhibit some other bacteria. A study was conducted in a group of 60 children to ascertain whether any correlation exists between the proportion of salivary bacteria inhibiting and stimulating Streptococcus mutans and the oral health indices (DMFT, deft and Community Periodontal Index of Treatment Needs). A definite inverse correlation was observed between the percentage of salivary inhibiting S. mutans and untreated carious teeth (UCT).

Taurodontism in deciduous Molars - A Case Report

Taurodontism has a very low incidence in deciduous dentition and very few cases are reported in the literature, it stands a challenge when it requires pulp therapy. This case report presents a case of Taurodontism in deciduous molars of a five year old male child which required pulp therapy. A clinical and radiographic follow up of the patient is discussed.

Oral melanotic macule--a case report

A melanotic macule is a benign pigmented lesion of oral cavity characterised by increase in melanin pigmentation. Presented here is a case report of 12 year old girl with black pigmented area on right buccal mucosa. An excision biopsy was done which confirmed the diagnosis by as melanotic macule.

Radicular cyst associated with endodontically treated deciduous tooth: a case report

This article presents a case report of radicular cyst associated with an endodontically treated deciduous second molar causing displacement of the permanent successor, with accompanying buccal expansion. Cystic sac was removed surgically along with the involved tooth under general anesthesia. Healing was uneventful. Histopathologically the cystic sac was consistent with the features of radicular cyst. Unusual amorphous, eosinophilic, atubular material incorporated within the cystic epithelium was observed.

Microbial contamination of tooth brushes and their decontamination

With the dawn of the new century, dentistry has seen a new face in the fields of diagnosis, treatment and prevention. Twenty one children were asked to brush their teeth for five days. The brushes were put in Robertson's Cooked Meat broth and cultured. Growth of Streptococcus Mutans were seen. These brushes were then placed in disinfectants such as 0.2% chlorhexidine gluconate (Gp I), 1% sodium hypochlorite(Gp II) and water (Gp III) for 24 hrs and then cultured. Disappearance of growth of microorganisms was seen in Gp I and Gp II and remnants of growth seen in Gp III. It can be concluded that the use of disinfectant is a must for every individual at regular intervals.

Acidogenic potential of Soya infant formula in comparison with regular infant formula and bovine milk: a plaque pH study

Soya infant formulas are essential for infants intolerant to cow's milk. Soya formulas contains glucose syrup or maltodextrins instead of Lactose, which has led to concern that they are potentially more cariogenic than standard infant formulas containing lactose. The study was conducted to compare the acidogenic effect of Soya Infant formula, infant formula and bovine milk. The study group consisted of 75 children in the age group of 7-10 years. The plaque pH was measured using plaque pH meter, before and after rinsing with different samples for sixty minutes Soya infant formula is found to be more acidogenic than infant formula (with lactose) and bovine milk. This study demonstrates high caries inducing potential of Soya infant formula. Further awareness of the possible role of Soya infant formula in early childhood caries is required.

Traumatic bone cyst--a case report

Traumatic bone cyst is an asymptomatic, slow growing, non expansile lesion commonly diagnosed during routine radiographic examination of the jaw bones. It is more frequently seen in young age, with predilection for anterior region of the mandible leading to a dramatic healing of the lesion. A typical case of traumatic bone cyst in a 12 year old girl is reported. A routine radiologic assessment of the patient with panoramic radiograph revealed a fairly large lesion in the anterior region of the mandible. On surgical exploration, clinical diagnosis was confirmed. Post operative successive radiograph shows progressive osseous healing.

Peripheral giant cell granuloma--a case report

Peripheral giant cell granuloma is a lesion arising mainly from the connective tissue of gingiva or periosteum of alveolar ridge. A case of peripheral giant cell granuloma involving a deciduous molar and the succedaneous tooth is reported. The lesion was large and interfered with occlusion. Surgical excision of the lesion along with the deciduous first molar was done. The underlying permanent first premolar was also involved, and had to be removed. The importance of an adequate salivary flow and maintenance of oral hygiene in the prevention of such lesions is stressed.

Laser and sound scanner for non-contact 3D volume measurement and surface texture analysis

Non-invasive three-dimensional measurement of volume and analysis of surface texture is desired in various medical applications, particularly wound healing measurements. In this paper we present a PC-based non-contact laser scanner for volume measurements, and a sound scanner that can accurately measure volumes and analyse surface textures. The non-invasive laser and sound sensors, which are lightweight, are mounted inverted on an X-Y table and the sensor heads are held at a distance of 3 cm from the object to be scanned. Volumes of various shapes on different materials, simulating depth profiles and surfaces of wounds, have been measured accurately and surface textures of varying softness have been analysed. The ratios of measured to actual volume range between 0.8 for the sound sensor and 1.1 for the laser sensor. A linear relation between hardness of 50%-20% concentration gelatin gel surfaces and amplitude of reflected sound waves is also observed. The average time per pass of a scan, for a distance of 3 cm, is 4 s and the computation time for measuring volume and reconstruction of a 3D image using ten passes per scan is 1 min. The unique features of this scanner are its speed, portability, accuracy and simple operation as well as its ability to be used on both soft and hard surfaces.