Electron-positron pair plasmas represent a unique state of matter, whereby there exists an intrinsic and complete symmetry between negatively charged (matter) and positively charged (antimatter) ...particles. These plasmas play a fundamental role in the dynamics of ultra-massive astrophysical objects and are believed to be associated with the emission of ultra-bright gamma-ray bursts. Despite extensive theoretical modelling, our knowledge of this state of matter is still speculative, owing to the extreme difficulty in recreating neutral matter-antimatter plasmas in the laboratory. Here we show that, by using a compact laser-driven setup, ion-free electron-positron plasmas with unique characteristics can be produced. Their charge neutrality (same amount of matter and antimatter), high-density and small divergence finally open up the possibility of studying electron-positron plasmas in controlled laboratory experiments.
Cryopreservation is the method of preservation of biological tissues for future references without causing significant damages to their physical and functional properties. This can be done by ...exposing them to very low cryogenic temperature that involves a greater heat removal rate. A two dimensional numerical model is developed to study the temperature distribution, cooling rate attained and movement of the freezing front during the cryopreservation process. The Pennes Bio-heat model is used for current study. The Finite Volume Method is employed for discretization of the governing differential equations while the Tri-Diagonal Matrix Algorithm is used to solve the discretized algebraic equations to find temperature distribution inside the domain. The Enthalpy-Porosity method is used to track the solid-liquid interfaces during the freezing process. The current model is first validated with the result of the existing literature. In the present work, freezing of tissue is done from one and two sides in two separate cases and the resulting temperature distribution inside the tissue and cooling rate in the two cases are compared. It is found that the freezing rate of tissue is enhanced about two times when it is freezed from two sides as compared to freezing from single side. Further, it is observed that a lower value of blood perfusion rate causes a lower value of the final temperature of the tissue after freezing. Thus, it can be concluded that the tissue with high blood perfusion rate is to be freezed in a lower cooling medium temperature. In the present condition, metabolic heat generation plays no significant role in the temperature distribution inside the healthy tissue.
•A two dimensional numerical model is developed to study the cryopreservation in biological tissue.•Pennes Bio-heat model is used for current study.•The freezing is done from two sides of the tissue by which the cooling rate is enhanced and the total freezing time is reduced which is the essential requirement of the cryopreservation process.•With increase in blood perfusion rate, the cooling rate reduces which necessitates the application of lower cryopreservation temperature for freezing of biological tissues with higher blood perfusion rates.•Metabolic heat generation inside the biological tissue has a negligible role to play in the freezing of biological tissue.
Summary
This article reports detailed investigation of using different Phase Change Materials (PCM) in various designs of Thermal Energy Storage (TES) Devices: specifically, heat exchanger. The focus ...is on the performance analysis of different types of heat exchangers acting as TES having various PCMs which are substantially reviewed in this paper. The study highlights the difference in their geometry and performance output. Further, the importance of different performance enhancement methods with parametric study of different heat exchangers using PCM is described. From the detailed investigation, finally, it is realised that the different factors such as no. of outer tubes, no. of inner tubes, tube material selected, type of PCM, provision of an extended surface, use of different metal foams and nanoparticles, various types of composites, charging and discharging characteristics and packed and cascaded units are different heat transfer enhancement methods to improve the heat transfer. A novel kind of heat exchanger known as Webbed tube heat exchanger using PCM is discussed for an efficient TES unit. Further, a review of quantitative analysis of melting time, solidification time, charging and discharging time is discussed.
To know the different heat transfer enhancement methods in various types of heat exchangers using phasechange materials. To investigate different factors affecting charging and discharging rates of phase change materials in various PCM based heat exchangers. To study the role of metal foams, nano based phase change material and composite phase change material to improve the efficiency of a thermal energy storage system. To investigate the thermal performance of packed and cascaded heat exchangers. To study a novel kind of heat exchanger called Webbed Tube Heat Exchanger.
Abstract
An interfacial integration at the nanoscale domain through a core@shell (CS) nanostructure has constructively unbarred a wide dimension to researchers on biomedical applications, especially ...for magnetic fluid hyperthermia. Lately, the interconnection of the exchange bias effect (EBE) through the interface coupling to the magnetic heating efficiency has uttered its utmost prominence for researchers. Here, we delineate the ascendency of the heating ability through a coalescing assembly of mixed ferrite Co
0.5
Zn
0.5
Fe
2
O
4
(CZ) and soft magnetic material Fe
3
O
4
(F), by devising a network of CoZnFe
2
O
4
@Fe
3
O
4
(CZF) CS nanostructure. A hefty interface activity with validation of the EBE phenomenon is divulged through magnetic scrutiny for the CS sample. The magnetic nanoparticles heating response to applied magnetic field and frequency is discerned at three distinct fields, where the outcome prevailed to inflated specific loss power for CS CZF in distinction to bare F and CZ samples for all the assessments. Remarkably; a lofty intrinsic loss parameter is also perceived for the CS sample recorded to about 5.36 nHm
2
g
−1
; which is another eccentric outcome that significantly labels the CS CZF sample as a potentially high heating competence agent. This comprehension accords to a finer perspective to meliorate the theranostic environment for hyperthermia applications.
Eculizumab is a lifesaving yet expensive drug for atypical haemolytic uraemic syndrome (aHUS). Current guidelines advise a fixed-dosing schedule, which can be suboptimal and inflexible in the ...individual patient.
We evaluated the pharmacokinetics (PK) and pharmacodynamics (PD) classical pathway (CP) activity levels of eculizumab in 48 patients, consisting of 849 time-concentration data and 569 CP activity levels. PK-PD modelling was performed with non-linear mixed-effects modelling. The final model was used to develop improved dosing strategies.
A PK model with parallel linear and non-linear elimination rates best described the data with the parameter estimates clearance 0.163 L/day, volume of distribution 6.42 L, maximal rate 29.6 mg/day and concentration for 50% of maximum rate 37.9 mg/L. The PK-PD relation between eculizumab concentration and CP activity was described using an inhibitory Emax model with the parameter estimates baseline 101%, maximal inhibitory effect 95.9%, concentration for 50% inhibition 22.0 mg/L and Hill coefficient 5.42. A weight-based loading dose, followed by PK-guided dosing was found to improve treatment. On day 7, we predict 99.95% of the patients to reach the efficacy target (CP activity <10%), compared with 94.75% with standard dosing. Comparable efficacy was predicted during the maintenance phase, while the dosing interval could be prolonged in ∼33% of the population by means of individualized dosing. With a fixed-dose 4-week dosing interval to allow for holidays, treatment costs will increase by 7.1% and we predict 91% of the patients will reach the efficacy target.
A patient-friendly individualized dosing strategy of eculizumab has the potential to improve treatment response at reduced costs.
When a pulse of light reflects from a mirror that is travelling close to the speed of light, Einstein's theory of relativity predicts that it will be up-shifted to a substantially higher frequency ...and compressed to a much shorter duration. This scenario is realized by the relativistically oscillating plasma surface generated by an ultraintense laser focused onto a solid target. Until now, it has been unclear whether the conditions necessary to exploit such phenomena can survive such an extreme interaction with increasing laser intensity. Here, we provide the first quantitative evidence to suggest that they can. We show that the occurrence of surface smoothing on the scale of the wavelength of the generated harmonics, and plasma denting of the irradiated surface, enables the production of high-quality X-ray beams focused down to the diffraction limit. These results improve the outlook for generating extreme X-ray fields, which could in principle extend to the Schwinger limit. PUBLICATION ABSTRACT
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•Hf1-xGdxO2 thin films are deposited on Si by co-sputtering of Hf and Gd target.•Gd content is found to be increased up to 9 % with for RF power of 60 W.•The cubic phase transition ...has been observed for higher Gd doping concentration.•The higher k-value with reduced interface charge density is observed at 60 W.•The bipolar switching behavior of 9% Gd doped HfO2 films suits well for memristors.
Hf1−xGdxO2 thin films have been deposited on silicon substrates by co-sputtering with the variation in RF power of Gd target from 15 W to 90 W. The Gd content was found to be increased up to 15% with the rise in RF power of Gd to 90 W. At higher RF powers, the Hf1−xGdxO2 thin films have shown the evolution of cubic phase. The dielectric constant was found to be increased up to 33 for the Gd concentration of 9%. The oxide charge density was found to be decreased with the rise in RF power. The interface trap density has a minimum value for the film deposited at 60 W. The decrease in leakage current density was also observed for the Hf1−xGdxO2 films deposited at 90 W RF power of Gd target. The memristors, fabricated at Gd power of 60 W, have shown current on/off ratio of 332.
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