Optimum Size of Nanorods for Heating Application

Magnetic nanoparticles (MNP's) have become increasingly important in heating applications such as hyperthermia treatment of cancer due to their ability to release heat when a remote external alternating magnetic field is applied. It has been shown that the heating capability of such particles varies significantly with the size of particles used. In this paper, we theoretically evaluate the heating capability of rod-shaped MNP's and identify conditions under which these particles display highest efficiency. For optimally sized monodisperse particles, the power generated by rod-shaped particles is found to be equal to that generated by spherical particles. However, for particles which have a dispersion in size, rod-shaped particles are found to be more effective in heating as a result of the greater spread in the power density distribution curve. Additionally, for rod-shaped particles, a dispersion in the radius of the particle contributes more to the reduction in loss power when compared to a dispersion in the length. We further identify the optimum size, i.e the radius and length of nanorods, given a bi-variate log-normal distribution of particle size in two dimensions

Comparative study of plating versus conservative treatment in mid shaft fractures of clavicle

Background: Clavicle fractures represent up to 4% and 1% of all fractures, respectively. Historically, both fracture types have been treated conservatively with acceptable outcomes. The surgical correction of these fractures is currently being investigated as a viable alternative to conservative management.Methods: A systematic search of PubMed was performed to identify articles comparing open reduction and internal fixation (ORIF) with conservative treatment for clavicular fractures. Specific outcomes of interest were shoulder function, pain, strength, range of motion, and risk of non-union. Results: ORIF of midshaft clavicular fractures results in increased shoulder function within 6 weeks following treatment and a decreased risk of non-union. After 1 year, there was no longer a difference in shoulder function between groups. There was no difference in pain between treatment groups. Both ORIF and conservative treatment of extraarticular scapular fractures yield comparable results in shoulder function, range of motion, and strength following treatment.Conclusions: This study, early primary plate fixation of comminuted mid shaft clavicular fractures results in improved patient-oriented outcomes, improved surgeon-oriented outcomes, earlier return to function and decreased rates of non-union and malunion.

Clinical and functional outcome of isolated posterior cruciate ligament avulsion fractures treated by open reduction and internal fixation

Background: PCL ligament avulsion fracture injuries constitute about 3-20% of all the knee injuries. Isolated posterior cruciate ligament injuries are uncommon and often go undiagnosed in acutely injured knees. fracture. In the long run they cause severe functional disability of the knee joint. There is no consensus concerning the optimal surgical treatment approach for these injuries. Our study was to assess the functional and clinical outcome of isolated PCL avulsion fractures with open reduction and internal fixation.Methods: This is a prospective study of 27 patients with isolated PCL avulsion fractures, done in the department of orthopaedics in RNT medical college over a 2-year period. All were treated with open reduction and internal fixation with 4 mm cannulated cancellous screw and washer. Postoperatively, patient leg was immobilized in posterior POP slab for 2 weeks, allowing toe touch weight bearing. All patients were regularly followed-up. 3 cases of post operative wound infection were detected.Results: Of the 27 patients, there were 19 males and 8 females. All the cases showed good fracture union in an average of 12 weeks post operatively. In the first 6 weeks, all of them acquired an average knee flexion of 90 degrees and by 3 months, all of them had 125 degrees of free flexion possible.2 cases showed negative posterior draw sign. The knee scoring system assessment showed 21 cases of excellent result, 4 cases of good result and 2 cases of fair result.Conclusions: Though rare, PCL avulsion fractured are to be managed properly and treated surgically. PCL tibial avulsion fractures treated through Burk and Schaffer approach with open reduction and internal fixation produces good results

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Gas absorption in reactive slurries: particle dissolution near gas-liquid interface

The rates of gas absorption into reactive slurries constituted by “fine” particles of a sparingly soluble reactant are known to be enhanced when the particle size is smaller than the characteristic diffusional lengths of the reactive species. This study examines the process of particle dissolution and the consequent change in particle size(s) near the gas-liquid interface, in the presence of diffusional gradients, using Higbie's extended theory of mass transfer with chemical (instantaneous) reaction. The effect of changing particle size (including complete dissolution of the particles in this “film” zone) on the mechanism and extent of enhancement in the specific rate of absorption has been assessed using a population balance approach to track the interaction of the dissolution process with the evolving particle size distributions. It has been shown that the rates predicted from the proposed theory differ considerably from those computed using models available in the literature, for particles which are “small” enough. A variety of initial particle size distributions of different spreads have been used to show that for a given mean particle size, wide distributions produce lower enhancements in the specific rate than narrow ones. The specific rate-batch time trajectories for a typical batch slurry reactor have been generated along with the evolution of the particle size distributions in the bulk slurry phase in order to track the solid conversion as a function of batch time. Such conversions computed from theories available in the literature are likely to be gross overestimates in relation to the actual scenario. Some of the reported experimental absorption data have been reinterpreted in the light of the models developed here.© Elsevie

Impact of Internet on intermediaries

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.Includes bibliographical references (leaves 88-91).by Anurag Mehra.M.Eng

Manipulation of bulk reactions in multiphase systems by the use of microheterogeneous media

It is well known that the rates of fast, multiphase reactions, that occur in the diffusion zone near the interface, may be enhanced by the use of an additional, emulsified phase, which shows a high affinity for the rate limiting solute. However, the effect of such an additional phase on the rate behaviour of systems where slow reaction occurs dominantly in the bulk, well mixed region has not been assessed so far. This effect can be of great significance, especially in situations, where the reaction kinetics depend upon the reactant concentration in a complex way (e.g. substrate inhibition) and may be of particular importance in biochemical systems. In this study, the conversion behaviour of a model steroid system, namely, the biphasic, enzymatic conversion of testosterone in a batch reactor, has been explored in the presence of an emulsified oil phase. The kinetic rate of reaction of this species displays a maximum with respect to its concentration. It has been shown that the presence of an emulsified liquid phase can improve the substrate conversions significantly and that the extent of such an improvement depends upon the solubilizing capacity of this phase as well as its hold-up. The use of a microheterogeneous media, in lieu of a plain reactive liquid, can therefore be used to drive the reactor towards optimal behaviour with a view to maximizing the substrate conversions.© Elsevie

Simultaneous absorption of two gases with chemical reactions: selectivity variation in microheterogeneous media

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