Theoretical analysis on the bioheat transfer process has been an extremely important issue in a wide variety of bioengineering situations such as cancer hyperthermia, burn injury evaluation, brain hypothermia, disease diagnostics, thermal comfort analysis, cryosurgery and cryopreservation etc. In this chapter, the theoretical strategies towards exactly solving the three-dimensional (3-D) bioheat transfer problems for both cases with and without phase change were systematically illustrated based on the authors’ previous works. Typical closed form analytical solutions to the hyperthermia bioheat transfer problems with space or transient heating on skin surface or inside biological bodies were summarized. In addition, exact solutions to the 3-D temperature transients of tissues under various phase change processes such as cryopreservation of biomaterials or cryosurgery of living tissues subject to freezing by a single or multiple cryoprobes were also outlined. Such solution is comprehensive enough by taking full account of many different factors such as generalized initial and boundary conditions, blood perfusion heat transfer, volumetric heating of hyperthermia apparatus or heat sink of cryoprobes etc. For illustrating the applications of the present methods, part of the solutions were adopted to analyze the selected bioheat transfer problems. The versatility of these theoretical approaches to tackle more complex issues was also discussed. The obtained solutions are expected to serve as the basic foundation for theoretically analyzing bioheat transfer problems.

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Analytical Solutions to 3-D Bioheat Transfer Problems with or without Phase Change

Effect of green solvents physical, chemical, biological and bonding nature on 5-acetyl-thiophene-2-carboxylic acid by DFT and TD-DFT approach – An antiviral agent

Study of a non-reacting hypersonic flow over an external cavity with flow injection using DSMC method

Abstract Optimal retrofit of low-performance units (LPUs) is promising to abate overflow pollutant mass loading of sewer systems during wet-weathers. This study presents a combination of mathematical model and Sobol algorithm to help identify LPUs of sewer systems and design retrofitting strategies. Therefore, the solution to minimize the overflow pollutant mass loading from sewers systems can be efficiently obtained. The developed method was demonstrated at a catchment served by one wastewater treatment plant in Chaohu City, Anhui Province of China, with five pumping stations and a total sewer length of 58.3 km. Within the catchment, there are three rivers and a pool, which are the main waterbodies for receiving the overflow pollutant mass loading from the sewer system. Among them, Donghuancheng river was the most polluted and thus selected as the object for water quality improvement by LPU retrofits in the paper. After identifying the LPUs in the sewer system along Donghuancheng river, and developing the associated retrofitting strategies using Sobol sequence, the mitigations for overflow pollutant mass loading were analyzed. Results show that by applying the optimal retrofit strategy, i.e., increasing the conveyance capacities of two pumping stations by 2.5~3.2 times and augmenting the diameters of 12 sewers by 1.25~1.29 times along Donghuancheng river, the mass loading of chemical oxygen demand (COD) discharged into the river could be reduced by 40.6%. To further coordinate the abatement of overflow pollution and retrofit investment, Sobol sensitivity analysis was conducted to screen the dominant LPUs to update the optimal retrofit strategy. Using the updated strategy, the overflow COD mass loading (1100 kg) per overflow event could be close to that of non-updated strategy (1039 kg) while reducing the retrofitting length of sewers by 40%. Therefore, on the basis of the presented method, decision-makers can flexibly develop an optimal retrofitting strategy for enhancing conveyance and interception efficiencies of sewage and respond to the abatement of overflow pollutant mass loading in a cost-effective way. 

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Retrofitting low-performance units to abate sewer overflow pollution based on mathematical model and Sobol algorithm

An emergency (rescue) cervical cerclage can be offered to pregnant women presenting with dilatation and prolapsed membranes in the second trimester of pregnancy because of cervical insufficiency. This study aimed to investigate the effectiveness of an emergency cerclage in both singleton and twin pregnancies in the prevention of extreme premature birth.We performed a systematic literature search in PubMed and Embase from inception to June 2022 for transvaginal cervical emergency cerclages.All studies on transvaginal cervical emergency cerclages with at least 5 patients and reporting survival were included.Included studies were assessed for quality and risk of bias with an adjusted Quality In Prognosis Studies tool. Random-effects meta-analyses and meta-regressions were performed for the primary outcome: survival.Our search yielded 96 studies, incorporating 3239 women, including 14 studies with an expectant management control group, incorporating 746 women. Overall survival after cervical emergency cerclage was 74%, with a fetal survival of 88% and neonatal survival of 90%. Singleton and twin pregnancies showed similar survival, with a pregnancy prolongation of 52 and 37 days and a gestational age at delivery of 30 and 28 weeks, respectively. Meta-regression analyses indicated a significant inverse association between mean gestational age at diagnosis and pregnancy prolongation and no association between dilatation or gestational age at diagnosis and gestational age at delivery. Compared with expectant management, emergency cerclage significantly increased overall survival by 43%, fetal survival by 17% and neonatal survival by 22%, along with a significant pregnancy prolongation of 37 days and reduction in delivery at <28 weeks of gestation of 55%. These effects were more profound in singleton pregnancies than in twin pregnancies.This systematic review indicates that, in pregnancies threatened by extreme premature birth because of cervical insufficiency, emergency cerclage leads to significantly higher survival, accompanied by significant pregnancy prolongation and reduction in delivery at <28 weeks of gestation, compared with expectant management. The mean gestational age at delivery was 30 weeks, independent of dilatation or gestational age at diagnosis. Survival was similar for singleton and twin pregnancies, implying that emergency cerclage should be considered in both. 

The Efficacy of Emergency Cervical Cerclage in Singleton and Twin Pregnancies: a Systematic Review with Meta-analysis.

https://doi.org/10.1016/j.desal.2022.115798

Sources, fates and treatment strategies of typical viruses in urban sewage collection/treatment systems: A review

To compare the efficacy of two stitches versus one stitch in women with emergency cervical cerclage.

Comparison of two stitches versus one stitch for emergency cervical cerclage to prevent preterm birth in singleton pregnancies

In this paper, an opposing jet is applied to the space shuttle arc leading edge and the lifting body cone leading edge in the hypersonic condition of the rarefied flow field. The DSMC numerical algorithm is used to simulate and analyze the underlying working physics of the opposing jet. The results provide a reference for designing hypersonic vehicles in near space that reduce drag and protect against heat.

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Investigation on the Opposing Jet in the Hypersonic Rarefied Flow over a Vehicle Based on the DSMC Method

1) Cryogenic Laboratory, P. O. Box 2711, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China 2) Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China 3) Laboratory for High Performance Scientific Computing and Computer Simulation, Department of Computer Science, University of Kentucky, 773 Anderson Hall, Lexington, Kentucky 40506-0046, USA

https://www.cs.engr.uky.edu/~jzhang/pub/PAPER/liu1.pdf

Jun Zhang

Papers

Sources, fates and treatment strategies of typical viruses in urban sewage collection/treatment systems: A review

Comparison of two stitches versus one stitch for emergency cervical cerclage to prevent preterm birth in singleton pregnancies

Investigation on the Opposing Jet in the Hypersonic Rarefied Flow over a Vehicle Based on the DSMC Method

Theoretical evaluation on burn injury of human respiratory tract due to inhalation of hot gas at the early stage of fires 1

The Meshless Direct Simulation Monte Carlo method