Synthesis of polyethylene/starch hybrids using aqueous mini emulsion polymerization

Sustainability regarding the most produced plastic, polyethylene, was the main motivation factor behind research of this thesis. The aim was to synthesize hybrids of polyethylene and starch in an aqueous mini emulsion polymerization process using single-site catalysts. Two types of water soluble starches were applied: potato and hydroxyethyl starch. A trifluoromethane bearing nickel enolate catalyst and a 5-halo 3-methoxy salicyl aldiminate nickel pyridyl catalyst (with Cl and Br as halogen atoms) were used as polymerization catalysts, the latter two known to results in higher molecular weight polymer. The first catalyst turned to be sufficiently active with increased loads of starch and resulted in hybrids containing between 7.5 and 92.3 % starch. The salicylaldiminate catalysts only led to traces of polyethylene since the applied ethylene pressure of ca. 7.5 bar in the glass reactor was not sufficiently high to polymerize in aqueous solution. The hybrids were characterized using IR spectroscopy, TGA, density measurements, DSC, SEM and TEM. For the determination of the starch content the aqueous latex samples had to be washed with acetone to remove the surfactant (sodium dodecyl sulfate,) and co-surfactant (hexadecane). The SEM and TEM showed that the starch was uniformly distributed in the hybrids. Biodegradability tests were carried out with three different types of fungi, Aspergillus, Trichoderma, and Myrothecium for 21 days. Aspergillus turned out to be the most active in the metabolization of the starches with hydroxymethyl starch being degraded more rapidly than potato starch. The biodegraded samples were also characterized by IR, TGA, and DSC and SEM, verifying that the starch and soap were metabolized by the fungi whereas the polyethylene was not. The crystallinity of the polyethylene was slightly increased as a result of the biodegradation

Recent Advancements in Regenerative Dentistry: A Review

Although human mouth benefits from remarkable mechanical properties, it is very susceptible to traumatic damages, exposure to microbial attacks, and congenital maladies. Since the human dentition plays a crucial role in mastication, phonation and esthetics, finding promising and more efficient strategies to reestablish its functionality in the event of disruption has been important. Dating back to antiquity, conventional dentistry has been offering evacuation, restoration, and replacement of the diseased dental tissue. However, due to the limited ability and short lifespan of traditional restorative solutions, scientists have taken advantage of current advancements in medicine to create better solutions for the oral health field and have coined it “regenerative dentistry.” This new field takes advantage of the recent innovations in stem cell research, cellular and molecular biology, tissue engineering, and materials science etc. In this review, the recently known resources and approaches used for regeneration of dental and oral tissues were evaluated using the databases of Scopus and Web of Science. Scientists have used a wide range of biomaterials and scaffolds (artificial and natural), genes (with viral and non-viral vectors), stem cells (isolated from deciduous teeth, dental pulp, periodontal ligament, adipose tissue, salivary glands, and dental follicle) and growth factors (used for stimulating cell differentiation) in order to apply tissue engineering approaches to dentistry. Although they have been successful in preclinical and clinical partial regeneration of dental tissues, whole-tooth engineering still seems to be far-fetched, unless certain shortcomings are addressed

Ophthalmology research in the UK’s National Health Service: the structure and performance of the NIHR’s Ophthalmology research portfolio

Purpose- To report on the composition and performance of the portfolio of Ophthalmology research studies in the United Kingdom’s National Institute for Health Research (NIHR) Clinical Research Network (UK CRN). Methods- Ophthalmology studies open to recruitment between 1 April 2010 and 31 March 2018 were classified by: sub-specialty, participant age, gender of Chief Investigator, involvement of genetic investigations, commercial/ non-commercial, interventional/observational design. Frequency distributions for each covariate and temporal variation in recruitment to time and target were analysed. Results- Over 8 years, 137,377 participants were recruited (average of 15,457 participants/year; range: 5485–32,573) with growth by year in proportion of commercial studies and hospital participation in England (76% in 2017/18). Fourteen percent of studies had a genetic component and most studies (82%) included only adults. The majority of studies (41%) enrolled patients with retinal diseases, followed by glaucoma (17%), anterior segment and cataract (13%), and ocular inflammation (6%). Overall, 68% of non-commercial studies and 55% of commercial studies recruited within the anticipated time set by the study and also recruited to or exceeded the target number of participants. Conclusions- High levels of clinical research activity, growth and improved performance have been observed in Ophthalmology in UK over the past 8 years. Some sub-specialties that carry substantial morbidity and a very high burden on NHS services are underrepresented and deserve more patient-centred research. Yet the NIHR and its CRN Ophthalmology National Specialty Group has enabled key steps in achieving the goal of embedding research into every day clinical care

Bending and Phase Transformation Properties of a Force Gradient Nickel-Titanium Orthodontic Wire

Objective: Conventional nickel-titanium (NiTi) archwires have widespread application in orthodontics due to their unique properties and ability to move teeth with light, continuous forces, but a shortcoming is that they apply near-uniform force along anterior and posterior teeth. Since the force needed to effectively move teeth is a function of the root surface area and bony support, these archwires cause single-rooted teeth to move more than the multi-rooted molars. With the advent of laser-engineered force gradient NiTi orthodontic archwires, individual forces may be applied to different segments or individual teeth of the arch to maximize tooth movement. The aim of this study was to evaluate force distribution and phase transformation properties of a seven-zone force gradient nickel-titanium orthodontic archwire. Materials and Methods: SmartArch™ Laser Engineered CuNiTi archwires (0.016”; Ormco) with seven distinct force zones were investigated. They were compared to the conventional 27°C Superelastic CuNiTi archwires (0.016”; Ormco). A three-point bend test was performed to evaluate mechanical properties and a differential scanning calorimeter (DSC) was used to determine the austenite-finish (Af) temperature for each wire segment from the central incisor to second molar. Data were analyzed via a two-way ANOVA with factors of wire and zone. Results: The 27°C CuNiTi archwire exhibited an overall significantly different (p\u3c0.05) Af than the SmartArch™ wire. As expected, the CuNiTi wire exhibited statistically equivalent (p\u3e0.05) Af temperatures along each zone, whereas SmartArch™ showed significantly different (p\u3c0.05) Af temperatures along each zone, but in a pattern not as expected based upon advertised force values. There were significant differences (p\u3c0.05) for almost all the bending parameters when comparing CuNiTi wires to SmartArch™ wires. As expected, the SmartArch™ wires had statistically different (p\u3c0.05) force values along each zone, but in a pattern inconsistent with advertised force values. The CuNiTi wires also had statistically different (p\u3c0.05) force values among the zones, which was also inconsistent with its advertised properties. Conclusion: Based upon the different Af temperatures and force values, it appears thermal treatment via laser can alter the metallurgy, phase transformation, and mechanical properties of the SmartArch™ orthodontic archwire, but this commercial wire may not exhibit the advertised force distribution

Comparative study of intrathecal bupivacaine and bupivacaine with clonidine to assess degree of sensory and motor effect and postoperative analgesia in lower limb orthopedic surgeries

Background: Subarachnoid blockade amongst regional anesthesia has been most commonly used for performing abdominal and umbilical surgeries. There is persistent search for finding an adjuvant to local anesthetics to prolong its action along with hemodynamic stability. In this study we have used clonidine as an adjuvant to local anaesthetic agent and have assessed its ability to prolong motor and sensory blockade and hemodynamic stability. Methods: This observational study was conducted on 56 patients of ASA grade I/II, undergoing lower limb orthopedic surgeries who were divided into 2 groups: Group B : Injection 3.0 ml hyperbaric Bupivacaine 0.5% + 0.12 ml normal saline was given intrathecally and Group C : Injection 3.0 ml Bupivacaine (0.5% hyperbaric) + 0.12 ml injection clonidine (20 mcg) was given intrathecally. We compared duration of sensory and motor blockade, hemodynamic changes, duration of analgesia and complications in both groups. Result:  The onset of sensory and motor blockage was comparable in both groups. Duration of sensory and motor blockade was significantly longer in Group C than group B (P < 0.0001, P < 0.0001, respectively)

A New Phantom to Evaluate the Tissue Dissolution Ability of Endodontic Irrigants and Activating Devices

Abstract Objective The aim of this study was to introduce a gelatin/bovine serum albumin (BSA) tissue standard, which provides dissolution properties identical to those of biological tissues. Further, the study evaluated whether the utilization of endodontic activating devices led to enhanced phantom dissolution rates. Materials and Methods Bovine pulp tissue was obtained to determine a benchmark of tissue dissolution. The surface area and mass of samples were held constant while the ratio of gelatin and BSA were varied, ranging from 7.5% to 10% gelatin and 5% BSA. Each sample was placed in an individual test tube that was filled with an appropriate sodium hypochlorite solution for 1, 3, and 5 minutes, and then removed from the solution, blotted dry, and weighed again. The remaining tissue was calculated as the percent of initial tissue to determine the tissue dissolution rate. A radiopaque agent (sodium diatrizoate) and a fluorescent dye (methylene blue) were added to the phantom to allow easy quantification of phantom dissolution in a canal block model when activated using ultrasonic (EndoUltra) or sonic (EndoActivator) energy. Results The 9% gelatin + 5% BSA phantom showed statistically equivalent dissolution to bovine pulp tissue at all time intervals. Furthermore, the EndoUltra yielded significantly more phantom dissolution in the canal block than the EndoActivator or syringe irrigation. Conclusions Our phantom is comparable to biological tissue in terms of tissue dissolution and could be utilized for in vitro tests due to its injectability and detectability

Tuberculosis Management Practices of Private Practitioners in Pune Municipal Corporation, India

<div><p>Background</p><p>Private Practitioners (PP) are the primary source of health care for patients in India. Limited representative information is available on TB management practices of Indian PP or on the efficacy of India’s Revised National Tuberculosis Control Programme (RNTCP) to improve the quality of TB management through training of PP.</p><p>Methods</p><p>We conducted a cross-sectional survey of a systematic random sample of PP in one urban area in Western India (Pune, Maharashtra). We presented sample clinical vignettes and determined the proportions of PPs who reported practices consistent with International Standards of TB Care (ISTC). We examined the association between RNTCP training and adherence to ISTC by calculating odds ratios and 95% confidence intervals.</p><p>Results</p><p>Of 3,391 PP practicing allopathic medicine, 249 were interviewed. Of these, 55% had been exposed to RNTCP. For new pulmonary TB patients, 63% (158/249) of provider responses were consistent with ISTC diagnostic practices, and 34% (84/249) of responses were consistent with ISTC treatment practices. However, 48% (120/249) PP also reported use of serological tests for TB diagnosis. In the new TB case vignette, 38% (94/249) PP reported use of at least one second line anti-TB drug in the treatment regimen. RNTCP training was not associated with diagnostic or treatment practices.</p><p>Conclusion</p><p>In Pune, India, despite a decade of training activities by the RNTCP, high proportions of providers resorted to TB serology for diagnosis and second-line anti-TB drug use in new TB patients. Efforts to achieve universal access to quality TB management must account for the low quality of care by PP and the lack of demonstrated effect of current training efforts.</p></div

Association between exposure of private providers to Public Private Mix (PPM) and self-reported TB clinical treatment and diagnostic practices that are in accordance with international standards-Pune Municipal Corporation, India 2010.

<p>*Exposed to RNTCP training- Attended training programme.</p><p>**International Standards of TB Care.</p>†<p>Odds ratio relates to doctors who adhered to guidelines, by attendance of training relative to those who did not attend.</p