A novel bioactive nano-composite: synthesis and characterisation with potential use as dental restorative material

PhDIt is desirable for a dental restorative material to have bioactive and bonding properties. This study focuses on the synthesis of a covalently-linked polyurethane/nanohydroxyapatite (PU/nHA) composite and evaluates its chemical, physical, thermal and biochemical characteristics. nHA powder was produced from the sol-gel and novel composite material was chemically prepared by utilising solvent polymerisation. The resulting composites were analysed by chemical, thermal, and mechanical characterisations and electrospun to form fibre mats. The composites were hydrolytically degraded in deionised water and phosphate buffer solution (PBS) and were analysed. Bioactive behaviour was determined in modified-simulated body fluid. The bioadhesion with dentine was analysed in distilled water and artificial saliva. Cell growth and proliferation was measured and number of adhering bacteria was determined and serial dilution followed by plating for colony forming units per disc. Spectral analyses showed the grafted isocyanate and ether peaks on nHA indicating that urethane linkage was established. Covalent-linkage between nHA and PU were found in this novel composite with no silane agent. The physical and thermal properties were enhanced by nHA. These composites had high resistance toward hydrolysis and little degradation was observed. Bioadhesion and bioactivity analysis showed the composite adhered firmly on the tooth surface (dentine) and bond strength was similar to existing obturating material. Higher nHA content composite showed a thicker layer of adhesion. Cells were proliferated although at a lower rate of growth compared to PU, whereas, there was reduction in bacteria adhering to the grafted composite compared to PU. With its low bacterial adhesion and biocompatibility it may provide a promising solution to reduce infections. The electrospun nano-fibres were successfully developed and revealed no loose nHA particles. Hence, this novel composite has the potential to be used as a bioactive dental restorative material

Outcome of Chipping Method in Complex Non-Union of Long Bones

Objective: To determine the outcome of chipping method in the treatment of long bones complex non-union with autologous bone graft. Patients and Methods: This interventional study was conducted in orthopedics and trauma department Khyber teaching hospital, Peshawar. Duration of this study was January 2015 to January 2016. The consecutive nonprobability technique was used to collect the samples and twenty-one patients were managed with chipping method for complex non-union of long bones. All the patients were treated by appropriate fracture fixation, including revision of implants. and followed for at least 06 months postoperatively. Results: A total of 21 patients were included in the study among which 14(66.67%) were males and 7(33.33 %) were females. Mean age of the patients was 44 years (Range 20 to 80 years). Among them 13 patients had femoral shaft fracture non-union,5 patients had tibial shaft fracture non-union, 2 patients had humerus fracture non-union and one had radius/ulna fracture non-unions. Mean duration from trauma to non-union was 15 months (Range 6 months to two years). All the patients were treated with this method, using an autologous bone graft from the iliac crest and followed for at least six months postoperatively. Twenty patients obtained bony union successfully. One patient failed to get a union, requiring the second operation, three patients got ipsilateral knee stiffness and three patients got limb length discrepancy less than 2cm. Conclusion: Chipping method with autologous bone grafting is easy to perform and is an encouraging approach for enhancing bone healing in long bones complex non-union

Meshfree numerical approach for some time-space dependent order partial differential equations in porous media

In this article, the meshfree radial basis function method based on the Gaussian function is proposed for some time-space dependent fractional order partial differential equation (PDE) models. These PDE models have significant applications in chemical engineering and physical science. Some main advantages of the proposed method are that it is easy to implement, and the output response is quick and highly accurate, especially in the higher dimension. In this method, the time-dependent derivative terms are treated by Caputo fractional derivative while space-dependent derivative terms are treated by Riesz, Riemann-Liouville, and Grünwald-Letnikov derivatives. The proposed method is tested on some numerical examples and the accuracy is analyzed by $\|L\|_\infty$

Determination of Shear Bond Strength of Nanocomposite to Porcelain and Metal Alloy

Objective: To compare porcelain and metal repair done with both nanocomposite and conventional composite. Material and Methods: A total of 30 cylinders were fabricated from Porcelain (I), Porcelain fused to metal (II), and metal (III) substrate each. Control group (A) was bonded with conventional micro-hybrid composite and experimental group (B) was bonded with nanocomposite in a 2 mm thickness. All specimens were thermocycled and stored in distilled water at 37 °C for 7 days. A universal testing machine was used to measure the Shear bond strength (SBS). The difference between bond strengths of the groups was compared using an independent t-test. Results: In all three groups, the SBS was higher in the experimental group as compared to the control group. The use of nanocomposite of metal alloy presented maximum shear bond strength, followed by samples of porcelain fused to metal and finally porcelain, showing the lowest values of SBS. Conclusion: Porcelain and alloys bonded with nanocomposite exhibit enhanced adhesiveness as well as aesthetic and mechanical properties. This subsequently would translate into providing higher clinical serviceability and durability and hence a cost-effective and accessible repair option for human welfare

Evaluation of the diuretic potentials of naringenin in hypercholesterolemic rats

Purpose: To investigate the diuretic potentials of naringenin (NGN) in obesity induced in rats by high fat diet (HFD).Methods: To prepare HFD, normal pellet diet was crushed and thoroughly mixed with cholesterol powder (1 % w/w). The mixture was mixed with some water and made into pellets which were then oven-baked to dry. Four groups of male Wistar albino rats (n = 6) were used for the study. Normal control (group I) received normal pellet diet. Group 2 (HFD-only) was fed HFD for 28 days, while Groups 3 and 4 were co-administered HFD and NGN at doses of 50 and 100 mg/kg, respectively. All treatments were given orally, and lasted for 28 days. Twenty-four hours after the last dose of NGN, blood was collected from all rats and total cholesterol levels determined to confirm obesity. Thereafter, the rats were placed in metabolic cages and urine samples were collected at two time-points (5 and 24 h) for measurement of urine volume, urinary pH, conductivity and electrolyte levels (Na, K and Cl).Results: Treatment with HFD resulted in significantly (p < 0.05) increased serum cholesterol level (178.83 ± 5.43 mg/dL) when compared to normal control rats (88.17 ± 4.04 mg/dL). It also led to decrease in urinary volume (~50 %) at both time points (5 and 24 h) and in excretion of urinary electrolytes (sodium, potassium and chloride ions). However, the changes in these parameters were significantly reversed by NGN administration (p < 0.05).Conclusion: These results demonstrate the diuretic activity of NGN in HFD-induced obese rats. Thus, NGN can be further explored for use in combination with hypolipidemic agents to tackle obesity.Keywords: High-fat diet, Hypercholesterolemia, Naringenin, Obesit

Identification and characterization of rhizospheric microbial diversity by 16S ribosomal RNA gene sequencing

In the present study, samples of rhizosphere and root nodules were collected from different areas of Pakistan to isolate plant growth promoting rhizobacteria. Identification of bacterial isolates was made by 16S rRNA gene sequence analysis and taxonomical confirmation on EzTaxon Server. The identified bacterial strains were belonged to 5 genera i.e. Ensifer, Bacillus, Pseudomona, Leclercia and Rhizobium. Phylogenetic analysis inferred from 16S rRNA gene sequences showed the evolutionary relationship of bacterial strains with the respective genera. Based on phylogenetic analysis, some candidate novel species were also identified. The bacterial strains were also characterized for morphological, physiological, biochemical tests and glucose dehydrogenase (gdh) gene that involved in the phosphate solublization using cofactor pyrroloquinolone quinone (PQQ). Seven rhizoshperic and 3 root nodulating stains are positive for gdh gene. Furthermore, this study confirms a novel association between microbes and their hosts like field grown crops, leguminous and non-leguminous plants. It was concluded that a diverse group of bacterial population exist in the rhizosphere and root nodules that might be useful in evaluating the mechanisms behind plant microbial interactions and strains QAU-63 and QAU-68 have sequence similarity of 97 and 95% which might be declared as novel after further taxonomic characterization

An electronic textile embedded smart cementitious composite

Abstract: Structural health monitoring (SHM) using self‐sensing cement‐based materials has been reported before, where nano‐fillers have been incorporated in cementitious matrices as functional sensing elements. A percolation threshold is always required in order for conductive nano‐fillers modified concrete to be useful for SHM. Nonetheless, the best pressure/strain sensitivity results achieved for any self‐sensing cementitious matrix are <0.01 MPa−1. In this work, we introduce for the first‐time novel partially reduced graphene oxide based electronic textile (e‐textile) embedded in plain and as well as in polymer‐binder‐modified cementitious matrix for SHM applications. These e‐textile embedded cementitious composites are independent of any percolation threshold due to the interconnected fabric inside the host matrix. The piezo‐resistive response was measured by applying direct and cyclic compressive loads (ranging from 0.10 to 3.90 MPa). A pressure sensitivity of 1.50 MPa−1 and an ultra‐high gauge factor of 2000 was obtained for the system of the self‐sensing cementitious structure with embedded e‐textiles. The sensitivity of this new system with embedded e‐textile is an order of magnitude higher than the state‐of‐the‐art nanoparticle based self‐sensing cementitious composites. The composites showed mechanical stability and functional durability over long‐term cyclic compression tests of 1000 cycles. Additionally, a two time‐constant model was used to validate the experimental results on decay response of the e‐textile embedded composites

Determination of Shear Bond Strength of Nanocomposite to Porcelain and Metal Alloy

Objective: To compare porcelain and metal repair done with both nanocomposite and conventional composite. Material and Methods: A total of 30 cylinders were fabricated from Porcelain (I), Porcelain fused to metal (II), and metal (III) substrate each. Control group (A) was bonded with conventional micro-hybrid composite and experimental group (B) was bonded with nanocomposite in a 2 mm thickness. All specimens were thermocycled and stored in distilled water at 37 °C for 7 days. A universal testing machine was used to measure the Shear bond strength (SBS). The difference between bond strengths of the groups was compared using an independent t-test. Results: In all three groups, the SBS was higher in the experimental group as compared to the control group. The use of nanocomposite of metal alloy presented maximum shear bond strength, followed by samples of porcelain fused to metal and finally porcelain, showing the lowest values of SBS. Conclusion: Porcelain and alloys bonded with nanocomposite exhibit enhanced adhesiveness as well as aesthetic and mechanical properties. This subsequently would translate into providing higher clinical serviceability and durability and hence a cost-effective and accessible repair option for human welfare

Healthcare Access Among Individuals of Asian Descent in the U.S.

Introduction. Some groups of Asian Americans, especially Asian Indians, experience higher rates of atherosclerotic cardiovascular disease (ASCVD) compared with other groups in the U.S. Barriers in accessing medical care partly may explain this higher risk as a result of delayed screening for cardiovascular risk factors and timely initiation of preventive treatment. Methods. Cross-sectional data were utilized from the 2006 to 2015 National Health Interview Survey (NHIS). Barriers to accessing medical care included no place to seek medical care when needed, no healthcare coverage, no care due to cost, delayed care due to cost, inability to afford medication, or not seeing a doctor in the past 12 months. Results. The study sample consisted of 18,150 Asian individuals, of whom 20.5% were Asian Indian, 20.5% were Chinese, 23.4% were Filipino, and 35.6% were classified as “Other Asians”. The mean (standard error) age was 43.8 (0.21) years and 53% were women. Among participants with history of hypertension, diabetes mellitus, or ASCVD (prevalence = 25%), Asian Indians were more likely to report delayed care due to cost (2.58 (1.14,5.85)), while Other Asians were more likely to report no care due to cost (2.43 (1.09,5.44)) or delayed care due to cost (2.35 (1.14,4.86)), compared with Chinese. Results among Filipinos were not statistically significant. Conclusions. Among Asians living in the U.S. with cardiovascular risk factors or ASCVD, Asian Indians and Other Asians are more likely to report delayed care or no care due to cost compared with Chinese