Effect of Adding Nano Size Silica on Setting Time and Porosity of Mineral Trioxide Aggregate

Introduction: The aim of this study was to evaluate the effect of addition of nano-silica (SiO2) to mineral trioxide aggregate (MTA) on its setting time and porosity. Methods and Materials: The concentration 8% of nano-silica were prepared and added to the MTA powder. After mixing with water the setting time and porosity were evaluated and compared with pure MTA. Statistical analysis was performed using the t-test. The level of significance was set at 0.001. Results: The mean setting time of MTA+8% nano-silica (9.8±0.78) was significantly lower than MTA (23.3±2.16) (P<0.001). Also the mean porosity by imbibition method in MTA+8% nano-silica (23.49±0.48) was significantly higher than MTA (15.69±2.10) (P<0.001). There was no significant difference in mean porosity by scanning electron microscope (SEM) method in MTA+8% nano-silica (31.26±10.73) and MTA (32.74±5.26) (P>0.001). Conclusion: This in vitro study showed us an addition of 8% of nano-silica to MTA reduced the setting time. Although evaluation by imbibition test showed increasing of porosity in nano-silica MTA compared with pure MTA.Keywords: Mineral Trioxide Aggregate; Nano-silica; Porosity; Setting Tim

The global, regional, and national burden of cirrhosis by cause in 195 countries and territories, 1990-2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background Cirrhosis and other chronic liver diseases (collectively referred to as cirrhosis in this paper) are a major cause of morbidity and mortality globally, although the burden and underlying causes differ across locations and demographic groups. We report on results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 on the burden of cirrhosis and its trends since 1990, by cause, sex, and age, for 195 countries and territories. Methods We used data from vital registrations, vital registration samples, and verbal autopsies to estimate mortality. We modelled prevalence of total, compensated, and decompensated cirrhosis on the basis of hospital and claims data. Disability-adjusted life-years (DALYs) were calculated as the sum of years of life lost due to premature death and years lived with disability. Estimates are presented as numbers and age-standardised or age-specific rates per 100 000 population, with 95% uncertainty intervals (UIs). All estimates are presented for five causes of cirrhosis: hepatitis B, hepatitis C, alcohol-related liver disease, non-alcoholic steatohepatitis (NASH), and other causes. We compared mortality, prevalence, and DALY estimates with those expected according to the Socio-demographic Index (SDI) as a proxy for the development status of regions and countries. Findings In 2017, cirrhosis caused more than 1.32 million (95% UI 1.27-1.45) deaths (440000 [416 000-518 000; 33.3%] in females and 883 000 [838 000-967 000; 66.7%] in males) globally, compared with less than 899 000 (829 000-948 000) deaths in 1990. Deaths due to cirrhosis constituted 2.4% (2.3-2.6) of total deaths globally in 2017 compared with 1.9% (1.8-2.0) in 1990. Despite an increase in the number of deaths, the age-standardised death rate decreased from 21.0 (19.2-22.3) per 100 000 population in 1990 to 16.5 (15.8-18-1) per 100 000 population in 2017. Sub-Saharan Africa had the highest age-standardised death rate among GBD super-regions for all years of the study period (32.2 [25.8-38.6] deaths per 100 000 population in 2017), and the high-income super-region had the lowest (10.1 [9.8-10-5] deaths per 100 000 population in 2017). The age-standardised death rate decreased or remained constant from 1990 to 2017 in all GBD regions except eastern Europe and central Asia, where the age-standardised death rate increased, primarily due to increases in alcohol-related liver disease prevalence. At the national level, the age-standardised death rate of cirrhosis was lowest in Singapore in 2017 (3.7 [3.3-4.0] per 100 000 in 2017) and highest in Egypt in all years since 1990 (103.3 [64.4-133.4] per 100 000 in 2017). There were 10.6 million (10.3-10.9) prevalent cases of decompensated cirrhosis and 112 million (107-119) prevalent cases of compensated cirrhosis globally in 2017. There was a significant increase in age-standardised prevalence rate of decompensated cirrhosis between 1990 and 2017. Cirrhosis caused by NASH had a steady age-standardised death rate throughout the study period, whereas the other four causes showed declines in age-standardised death rate. The age-standardised prevalence of compensated and decompensated cirrhosis due to NASH increased more than for any other cause of cirrhosis (by 33.2% for compensated cirrhosis and 54.8% for decompensated cirrhosis) over the study period. From 1990 to 2017, the number of prevalent cases snore than doubled for compensated cirrhosis due to NASH and more than tripled for decompensated cirrhosis due to NASH. In 2017, age-standardised death and DALY rates were lower among countries and territories with higher SDI. Interpretation Cirrhosis imposes a substantial health burden on many countries and this burden has increased at the global level since 1990, partly due to population growth and ageing. Although the age-standardised death and DALY rates of cirrhosis decreased from 1990 to 2017, numbers of deaths and DALYs and the proportion of all global deaths due to cirrhosis increased. Despite the availability of effective interventions for the prevention and treatment of hepatitis B and C, they were still the main causes of cirrhosis burden worldwide, particularly in low-income countries. The impact of hepatitis B and C is expected to be attenuated and overtaken by that of NASH in the near future. Cost-effective interventions are required to continue the prevention and treatment of viral hepatitis, and to achieve early diagnosis and prevention of cirrhosis due to alcohol-related liver disease and NASH. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd.Peer reviewe

Mapping 123 million neonatal, infant and child deaths between 2000 and 2017

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations

INTERACTIVE PLATFORM FOR MEDICAL PROCEDURES IN MIXED REALITY

Physicians often rely on medical imaging to diagnose, treat, or operate on patients. High fidelity imaging modalities such as MRI and CT have revolutionized medical practice, affording surgeons better preoperative diagnosis and planning. This wealth of imaging data is not readily accessed during procedures, however, sometimes leading to avoidable errors in localizing or reaching an internal target and performing the anatomic restoration. Currently, physicians must look away from the operative field, consult static images on a computer screen, and then use spatiotemporal reasoning to estimate how the images translate to the actual patient. Mixed reality is an emerging technology that connects virtual space and the real world seamlessly and enables the physicians to visualize anatomical targets directly on the patient's anatomy. This dissertation presents the architecture and implementation of an interactive mixed reality platform for medical procedures. It discusses the critical challenges with head-mounted optical see-through systems that needed to be addressed in this implementation. Various use cases of this platform are discussed and evaluated in detail. For surgery, our navigation system uses mixed reality on a head-mounted display that directly overlays preoperative imaging on the operative field. This ``x-ray'' vision brings the information from preoperative imaging to where the surgeon needs to use it, reducing error and facilitating better outcomes. It provides the surgeon with the location of the desired target overlaid intraoperatively directly on the patient’s anatomy. It also assesses the benefits of using mixed reality for training medical procedures. Through several controlled user-studies using phantoms, this thesis demonstrates the system's performance and usability. Working with leading surgeons at Johns Hopkins Hospital, this work also discusses the practical implications of bringing our platform to clinical readiness for various procedures

The 7th World Congress on Itch

The 7th World Congress on Itch was held in Boston in September 2013. This is the biennial meeting of the International Forum for the Study of Itch (IFSI), www.itchforum.net, There were 240 attendees from 17 countries. They spanned clinical practice, academics and patient advocacy while the opportunity for translation was demonstrated as 80 attendees were from industry. A large academic neuroscience contingent was present. There were plenary sessions, basic and clinical tracts, and sixty posters during the 2½ day meeting. The meeting program and 160 abstracts are available at www.itchboston.org and the open access journal, Acta Dermato-Venereologica, www.medicaljournals.se/acta/. This report highlights selected aspects of the congress and the latest advances in the field

The association between atorvastatin administration and plasma total homocysteine levels in renal transplant recipients

Background: Statins improve prognosis in patients with coronary heart diseases by decreasing the incidence of vascular events. Excess prevalence of hyperhomocysteinemia, an independent risk factor of cardiovascular diseases, has been observed in stable renal transplant recipients (RTRs). Objectives: The objective of our study was to evaluate the association between atorvastatin administration and plasma total homocysteine (tHcy) levels in RTRs. Patients and Methods: We performed a retrospective cross-sectional study in 148 cyclosporine A (CsA) treated stable RTRs. We compared tHcy level and other demographic and clinical variables in RTRs with and without atorvastatin. Results: 58.1% of the 148 RTRs were treated with atorvastatin (20-40 mg/day). Mean tHcy levels were lower in patients treated with atorvastatin compared to nonusers (14.80 ± 5.13 µmol/l versus 16.95 ± 7.87 µmol/l, P = 0.04). The comparison of 85 patients treated with atorvastatin and 61 non-users revealed that those subjects with atorvastatin were older, with higher estimated creatinine clearance and elevated body mass index (BMI). They were more likely to have higher systolic blood pressure and CsA trough level (C0). The association between lower tHcy levels and atorvastatin use was confirmed in the multivariate regression model (P = 0.004). However tHcy levels were independently and negatively associated with serum folate (P = 0.0001) and vitamin B12 levels (P = 0.001) and positively with serum BUN (P = 0.001) and diastolic blood pressure (P = 0.024) as well. Conclusions: These data support the association between lower tHcy levels and atorvastatin administration in RTRs. Further clinical trials are recommended to clarify homocysteine lowering effect of atorvastatin

Three-Dimensional Smooth Trajectory Planning Using Realistic Simulation

Abstract. This paper presents a method for planning three-dimensional walking patterns for biped robots in order to obtain stable smooth dynamic motion and also maximum velocity during walking. To determine the rotational trajectory for each actuator, there are some particular key points gained from natural human walking whose value is defined at the beginning, end and some intermediate or specific points of a motion cycle. The constraint equation of the motion between the key points will be then formulated in such a way to be compatible with geometrical constraints. This is first done in sagittal and then developed to lateral plane of motion. In order to reduce frequent switching due to discrete equations which is inevitable using coulomb dry friction law and also to have better similarity with the natural contact, a new contact model for dynamic simulation of foot ground interaction has been developed which makes the cyclic discrete equations continuous and can be better solved with ODE solvers. Finally, the advantages of the trajectory described are illustrated by simulation results

Endodontic guided treatment using augmented reality on a head-mounted display system

Endodontic treatment is performed to treat inflamed or infected root canal system of any involved teeth. It is estimated that 22.3 million endodontic procedures are performed annually in the USA. Preparing a proper access cavity before cleaning/shaping (instrumentation) of the root canal system is among the most important steps to achieve a successful treatment outcome. However, accidents such as perforation, gouging, ledge and canal transportation may occur during the procedure because of an improper or incomplete access cavity design. To reduce or prevent these errors in root canal treatments, this Letter introduces an assistive augmented reality (AR) technology on the head-mounted display (HMD). The proposed system provides audiovisual warning and correction in situ on the optical see-through HMD to assist the dentists to prepare access cavity. Interaction of the clinician with the system is via voice commands allowing the bi-manual operation. Also, dentist is able to review tooth radiographs during the procedure without the need to divert attention away from the patient and look at a separate monitor. Experiments are performed to evaluate the accuracy of the measurements. To the best of the authors’ knowledge, this is the first time that an HMD-based AR prototype is introduced for an endodontic procedure