Conversion of pyrolytic non-condensable gases from polypropylene co-polymer into bamboo-type carbon nanotubes and high-quality oil using biochar as catalyst.

The conversion of low-value plastic waste into high-value products such as carbon nanomaterial is of recent interest. In the current study, the non-condensable pyrolysis gases, produced from Polypropylene Copolymer (PPC) feedstock, was converted into bamboo-type carbon nanotubes (BCNTs) through catalytic chemical vapour deposition using biochar. Experiments were conducted in a three-zone furnace fixed bed reactor, where PPC was pyrolysed in the second zone and carbon nanotubes (CNTs) growth was eventuated in the third zone. The effects of different growth temperatures (500, 700, 900 °C) and biochar particle sizes (nanoparticle as well as 0-100 and 100-300 µm) were investigated to optimise the production of hydrogen and the yield of carbon nanotubes on the biochar surface. Biochar samples used in the synthesis of CNTs were obtained from the pyrolysis of saw dust at 700 °C in a muffle furnace. Analyses performed by using Scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, and Raman spectroscopy techniques suggested that the best crystalline structure of CNTs were obtained at 900 °C with nano-sized biochar as a catalyst. The strong gas-solid contact and void fraction of nano-sized particles enhances the diffusion-precipitation mechanism, leading to the growth of CNTs. The nano-sized biochar increased hydrogen production at 900 °C and reduced the polycyclic aromatic hydrocarbons content in oil to only 1%, which is advantageous for further utilisation. Therefore, the production of high-value CNTs from waste plastic using low-cost biochar catalyst can be a sustainable approach in the management of waste plastic while participating in the circular economy.

Effect of substitution of plasticizer dibutyl phthalate with dibutyl sebacate on Eudragit® RS30D drug release rate control.

In the current study, the influence of type of plasticizer used with Eudragit® RS 30D on the drug release was investigated in solid dosage form extrusion/spheronization, and film coating. The drug pellets were coated for controlling drug release with Eudragit® RS 30D containing dibutyl phthalate and compared with dibutyl sebacate as an alternative plasticizer. To study the influence of pH of the dissolution medium on the drug release profile, capsules are tested for drug release profile at pH 1.2, 4.4, and 6.3. Additionally, the aging effect on the curing of Eudragit® RS 30D is evaluated by exposing the capsules dosage form to room temperature (25 °C ± 2 °C/60% ± 5% RH) for time 0, 3, 6, and 9 months, accelerated temperature (40 °C ± 2 °C/75% ± 5% RH) for time 0, 3, and 6 months, and intermediate temperature (30 °C ± 2 °C/65% ± 5% RH) for time 0, 6, and 9 months. The replacement of dibutyl phthalate, with dibutyl sebacate for polymer coating system in similar concentration is comparable with respect to plasticization effect. The coalescence of the polymer particles is not changed and requires no additional processing parameter control or additional curing time.

The role of occlusal loading in the pathogenesis of non-carious cervical lesions.

PURPOSE: To evaluate the putative role of occlusal loading in the pathogenesis of non-carious cervical lesions (NCCLs) in subjects who exhibited mixed excursive guidance [i.e., immediate canine guidance on one side and group function (GF) on the other]. METHODS: 20 subjects with Angle Class 1 occlusion and having from 1 to 5 NCCLs on separate teeth were selected. Only subjects who displayed mixed excursive guidance were recruited so that they could serve as their own controls. Non-carious cervical lesions were recorded on casts mounted in semi-adjustable articulators. RESULTS: On the GF sides, 22.5% of all teeth that contacted in working excursions exhibited NCCLs; only 2.1% of the teeth on the canine guided sides exhibited NCCLs, which were found exclusively in canines. Although a case for the multifactorial etiology of NCCLs remains strong, our data, albeit limited, seems to support the dominant role of occlusion in lesion formation.

Evaluating the efficacy and safety of calcipotriene/betamethasone ointment occluded with a hydrogel patch: a 6-week bilaterally controlled, investigator-blinded trial.

Occlusive therapy with or without topical agents is effective in the treatment of psoriasis. This study assessed the efficacy and safety of an occlusive hydrogel dressing. Participants were treated with calcipotriene 0.005%-betamethasone dipropionate 0.064% ointment with and without a hydrogel patch. Thirty participants completed the 6-week, bilaterally controlled, investigator-blinded, single-center study. Substantial reductions in total modified psoriasis area and severity index (PASI) scores of occluded lesions versus nonoccluded lesions were seen as early as the first week of treatment and sustained through 4 weeks of the study. No adverse effects related to the study, including skin irritation, were observed or reported. Hydrogel dressings provide an effective and safe occlusive option to enhance topical therapy for psoriasis.

Comparison of cutting efficiency with different diamond burs and water flow rates in cutting lithium disilicate glass ceramic.

BACKGROUND: This study compared different diamond burs and different water flow rates on the cutting efficiency of sectioning through lithium disilicate glass ceramic. METHODS: The authors used a standardized cutting regimen with 4 brands of diamond burs to section through lithium disilicate glass ceramic blocks. Twelve diamonds of each brand cut through the blocks in randomized order. In the first part of the study, the authors recorded sectioning rates in millimeters per minute for each diamond bur as a measure of cutting efficiency. In the second part of the study, the authors compared sectioning rates using only 1 brand of diamond bur, with 3 different water flow rates. RESULTS: The authors averaged and compared cutting rates of each brand of diamond bur and the cutting rates for each flow rate using an analysis of variance and determined the differences with a Tukey honest significant difference test. One diamond bur cut significantly slower than the other 3, and one diamond bur cut significantly faster than 2 of the others. The diamond bur cutting efficiency through lithium disilicate glass ceramic with a 20 mL/min water flow rate was significantly higher than 15 mL/min. CONCLUSIONS: There are differences in cutting efficiency between diamond burs when sectioning lithium disilicate glass ceramic. Use a minimum of 20 mL/min of water coolant flow when sectioning lithium disilicate glass ceramic with dental diamond burs to maximize cutting efficiency. PRACTICAL IMPLICATIONS: Recommendations for specific diamond burs with a coarse grit and water flow rate of 20 mL/min can be made when removing or adjusting restorations made from lithium disilicate glass ceramic.

Bioresorbable vascular scaffold for coronary in-stent restenosis: a novel concept.

The management of patients with significant in-stent restenosis (ISR) with drug-eluting stent is still not well defined. Various treatment modalities include plain old balloon angioplasty (POBA), metallic stent, cutting or scoring balloon and drug-eluting balloon (DEB). Bioresorbable vascular scaffold (BVS) is the latest technology for the treatment of de novo coronary artery lesions. The use of BVS in ISR is based on the rationale of local drug delivery as achieved by DEB without the permanent bi-layer of metal and also stabilizes dissection flaps and prevents acute recoil as provided by metallic stent. To the best of our knowledge this is the first case report of the use of BVS in patient with ISR.

Formulation of fenofibrate liquisolid tablets using central composite design.

Liquisolid technique has been widely used to enhance the dissolution of poorly water soluble drugs. The present investigation is on formulation of liquisolid tablets of fenofibrate, a lipid lowering agent. Liquisolid formulation was prepared by applying central composite design (CCD) to optimize various formulation parameters. Amounts of PEG 600 (X1), Avicel PH 102 (X2), and Aerosil 200 (X3) were selected as independent variables while the angle of repose, hardness, disintegration time, and T90% (time required to release 90% drug) of liquisolid tablets were selected as dependent variables. Optimization of formulation was done by multiple linear regression analysis. The results indicated amounts of PEG 600 and Aviel PH 102 show greater effect on dependant variables. In vitro dissolution of fenofibrate in liquisolid formulations was enhanced compared to the pure form. To conclude, Liquisolid technique is a promising strategy in improving dissolution of poorly water soluble fenofibrate.

Instant barrier repair: A pilot study investigating occlusion with a new hydrogel patch for the treatment of atopic dermatitis.

The ideal repair mechanism for overcoming barrier disruption in atopic dermatitis (AD) needs to completely eliminate microbe and allergen penetration as well as transepidermal water loss. We propose the hydrogel patch as an innovative approach to complete barrier repair. It is composed of an adhesive, thin, flexible, hydrogel layer on an impermeable urethane surface. We conducted a 6-week pilot study with 15 AD patients, who applied the hydrogel patch over one lesion for 6-8 h daily and triamcinolone (TAC) 0.1% cream twice daily to another lesion. Results after 2-week no treatment follow-up showed hydrogel patch had notable efficacy, and comparable to TAC 0.1% cream. Larger studies are needed to validate these results.

Management of guidewire-induced coronary artery perforations through transradial route - A simple approach.

We describe two cases of guidewire-induced Type-3 coronary artery perforations leading to pericardial tamponade treated successfully through a transradial approach using polyvinyl alcohol particles. This can be an effective, alternative, simplistic approach in the management of distal coronary artery perforations with hemodynamic compromise otherwise requiring surgical intervention.

Studies in preparation and evaluation of pH-independent sustained-release matrix tablets of verapamil HCl using directly compressible Eudragits.

The objective of the present study was to investigate the impact of formulation factors on the properties of a 12h modified-release formulation of verapamil HCl. A 2(3) full factorial design was employed to investigate the influence of amount of Eudragit RS PO/RL PO (X1, a matrixing agent), HPMC K4M (X2, an auxiliary matrixing agent cum binder) and PEG 4000 (X3, channelling agent cum plasticizer). The tablets were prepared by direct compression and they were evaluated for in vitro dissolution studies in 0.1 N HCl. The time required for 90% of the drug release (t90) and similarity factor (f2) were used as responses for the selection of most appropriate batches. Swelling and fluid penetration studies were carried out in 0.1 N HCl. Time required for 90% of the drug release (t90) was calculated by using an appropriate kinetic model for each batch. An ideal drug release profile (i.e., 25% in the first hour and a constant drug release thereafter) was considered as a reference release profile for calculation of f2. Multiple regression analysis was adopted to evolve refined models for t90. The required release pattern was shown by batches containing a low level of Eudragit RS PO/RL PO (30% w/w), low level of HPMC K4M (10% w/w), and high level of PEG 4000 (15% w/w). Response surface plots are shown for t90. These formulations showed slower drug release in alkaline medium (pH 7.2). Succinic acid and KH2PO4 were incorporated in the matrix in order to obtain pH-independent drug release. Swelling of tablets and fluid penetration in the matrix were found to be influenced by the selected independent variables. This study demonstrates that the desired drug release pattern can be obtained by adopting a systematic formulation approach.