The purpose of this paper is to consider 1D Riemann shock tube to investigate the formation and propagation of compression waves leading to formation, propagation and reflection of 1D normal shocks using simplified ma...The purpose of this paper is to consider 1D Riemann shock tube to investigate the formation and propagation of compression waves leading to formation, propagation and reflection of 1D normal shocks using simplified mathematical models commonly used in the published work as well as using complete mathematical models based on Conservation and Balance Laws (CBL) of classical continuum mechanics and constitutive theories for compressible viscous medium derived using entropy inequality and representation theorem. This work is aimed at resolving compression waves, the shock structure, shock formation, propagation and reflection of fully formed shocks. Evolutions obtained from the mathematical models always satisfy differentiability requirements in space and time dictated by the highest order of the derivatives of the dependent variables in the mathematical models investigated. All solutions reported in this paper including boundary conditions and initial conditions are always analytic. Solutions of the mathematical models are obtained using the space-time finite element method in which the space-time integral forms are space-time variationally consistent ensuring unconditionally stable computations during the entire evolution. Solution for a space-time strip or slab is calculated and is time marched upon convergence to obtain complete evolution for the desired space-time domain, thus ensuring time accurate evolutions. The space-time local approximation over a space-time element of a space-time strip or slab is p-version hierarchical with higher-order global differentiability in space and time, i.e., we consider scalar product approximation spaces in which k = (k<sub>1</sub>, k<sub>2</sub>) are the order of the space in space and time and p = (p<sub>1</sub>, p<sub>2</sub>) are p-levels of the approximations in space and time. Model problem studies are presented for different mathematical models and are compared with solutions obtained from the complete mathematical model based on CBL and constitutive theories for viscous compressible medium to illustrate the deficiencies and shortcomings of the simplified and approximate models in simulating correct physics of normal shocks.展开更多
Objectives: Evaluation of the effects of withholding plasma during the initial part of the burn shock period (the shock period in the study is estimated as the first 36 hours following the burns) when it will be lost ...Objectives: Evaluation of the effects of withholding plasma during the initial part of the burn shock period (the shock period in the study is estimated as the first 36 hours following the burns) when it will be lost into the interstitial tissues through the permeable capillaries. During that time crystalloids are administered. Another objective is to evaluate the effect of administering normal saline as the crystalloid resuscitation fluid during the initial part of the shock period. Design: A Retrospective 4 years study compares the use of normal saline as the resuscitative intravenous fluid during the first 12 hours post burns followed by intravenous 5% Purified Plasma Protein Fraction (PPPF) during the rest of the shock period i.e. the remaining 24 hours, with the use of the PPPF throughout the burns shock period according to Muir and Barclay formula. Setting: The Plastic Surgery Department and the Department of Laboratory, Directorate General of Khoula Tertiary Hospital, Muscat, Sultanate of Oman. Patients and Methods: The study included 2 groups of patients;Group A: Patients who received 5% Plasma (Human PPPF) throughout the shock period and Group B: Patients who received crystalloids in the form of normal saline during the first 12 hours post burn followed by plasma for the next 24 hours. Monitoring of the patients in both groups was done by using clinical signs of pulse, blood pressure, temperature and urine output and by using laboratory investigations in the form of the haematocrit value, sodium, potassium, chloride, total proteins and albumin levels in the blood at the time of admission and at the end of the shock period. Results: 140 patients were included in the study;64 in Group A and 76 in Group B. There was no mortality and the vital signs were maintained during the shock period in both groups. The mean values of urine output were nearer to the normal level in Group B compared to Group A. The same was observed regarding the Haematocrit value. In both groups the mean values showed no hypoproteinaemia or hypoalbuminaemia at the end of the shock period. There was no hypernatraemia in spite of giving 150 mmol/L of Na during the initial 12 hours post burns in Group B. The mean values of potassium and chloride levels were normal in both groups at the end of the shock period. Conclusion: Giving plasma during the first 12 hours of the burn shock period when the capillary leakage is maximum has no significant benefit. The plasma usage can be reduced by 50% compared to the use of the Muir and Barclay Formula from the beginning of the shock period with reduction of the costs and the possibility of transmission of undetected pathogens by nearly the same value if crystalloids are given during the first 12 hours of burns shock period. The use of isotonic normal saline during the first 12 hours appears more appropriate as it maintains adequate sodium balance to correct the hyponatraemia and at the same time prevents elevation of the serum potassium during the period when potassium is released from the cells. In addition, it does not have a significant reduction on the level of the serum proteins.展开更多
Selection of proper reference genes (RGs) is an essential step needed for accurate normalization of results from genomic studies. Expression of RGs is regulated by many factors such as species, age, gender, type of ti...Selection of proper reference genes (RGs) is an essential step needed for accurate normalization of results from genomic studies. Expression of RGs is regulated by many factors such as species, age, gender, type of tissue, the presence of disease, and the administration of therapeutic treatment. The aim of the present study was to identify optimal RGs in a set of blood samples collected at different time points (0, 24, 48, 72 h) from horses following administration of extracorporeal shock wave therapy (ESWT). The mRNA expression of twelve RGs: HPRT1, ACTB, HSP90A, SDHA, GUSB, B2M, UBC, NONO, TBP, H6PD, RPL32, GAPDH was determined using real time quantitative polymerase chain reaction (qPCR). An SAS program developed on the algorithm of geNorm, SASqPCR, was used to determine stability of the expression and the number of optimal RGs. The results showed that the range of quantification cycle (Cq) values of the evaluated genes varied between 17 and 26 cycles, and that one optimal RG, ACTB, was sufficient for normalization of gene expression. Results of stability of expression demonstrated that ACTB was the optimal choice for all the samples studied. Notably, in samples collected at 72 h post ESWT, TBP showed a significant change in the expression level, and was not suitable for use as a RG. These results substantiate the importance of validating and selecting an appropriate RG.展开更多
文摘The purpose of this paper is to consider 1D Riemann shock tube to investigate the formation and propagation of compression waves leading to formation, propagation and reflection of 1D normal shocks using simplified mathematical models commonly used in the published work as well as using complete mathematical models based on Conservation and Balance Laws (CBL) of classical continuum mechanics and constitutive theories for compressible viscous medium derived using entropy inequality and representation theorem. This work is aimed at resolving compression waves, the shock structure, shock formation, propagation and reflection of fully formed shocks. Evolutions obtained from the mathematical models always satisfy differentiability requirements in space and time dictated by the highest order of the derivatives of the dependent variables in the mathematical models investigated. All solutions reported in this paper including boundary conditions and initial conditions are always analytic. Solutions of the mathematical models are obtained using the space-time finite element method in which the space-time integral forms are space-time variationally consistent ensuring unconditionally stable computations during the entire evolution. Solution for a space-time strip or slab is calculated and is time marched upon convergence to obtain complete evolution for the desired space-time domain, thus ensuring time accurate evolutions. The space-time local approximation over a space-time element of a space-time strip or slab is p-version hierarchical with higher-order global differentiability in space and time, i.e., we consider scalar product approximation spaces in which k = (k<sub>1</sub>, k<sub>2</sub>) are the order of the space in space and time and p = (p<sub>1</sub>, p<sub>2</sub>) are p-levels of the approximations in space and time. Model problem studies are presented for different mathematical models and are compared with solutions obtained from the complete mathematical model based on CBL and constitutive theories for viscous compressible medium to illustrate the deficiencies and shortcomings of the simplified and approximate models in simulating correct physics of normal shocks.
文摘Objectives: Evaluation of the effects of withholding plasma during the initial part of the burn shock period (the shock period in the study is estimated as the first 36 hours following the burns) when it will be lost into the interstitial tissues through the permeable capillaries. During that time crystalloids are administered. Another objective is to evaluate the effect of administering normal saline as the crystalloid resuscitation fluid during the initial part of the shock period. Design: A Retrospective 4 years study compares the use of normal saline as the resuscitative intravenous fluid during the first 12 hours post burns followed by intravenous 5% Purified Plasma Protein Fraction (PPPF) during the rest of the shock period i.e. the remaining 24 hours, with the use of the PPPF throughout the burns shock period according to Muir and Barclay formula. Setting: The Plastic Surgery Department and the Department of Laboratory, Directorate General of Khoula Tertiary Hospital, Muscat, Sultanate of Oman. Patients and Methods: The study included 2 groups of patients;Group A: Patients who received 5% Plasma (Human PPPF) throughout the shock period and Group B: Patients who received crystalloids in the form of normal saline during the first 12 hours post burn followed by plasma for the next 24 hours. Monitoring of the patients in both groups was done by using clinical signs of pulse, blood pressure, temperature and urine output and by using laboratory investigations in the form of the haematocrit value, sodium, potassium, chloride, total proteins and albumin levels in the blood at the time of admission and at the end of the shock period. Results: 140 patients were included in the study;64 in Group A and 76 in Group B. There was no mortality and the vital signs were maintained during the shock period in both groups. The mean values of urine output were nearer to the normal level in Group B compared to Group A. The same was observed regarding the Haematocrit value. In both groups the mean values showed no hypoproteinaemia or hypoalbuminaemia at the end of the shock period. There was no hypernatraemia in spite of giving 150 mmol/L of Na during the initial 12 hours post burns in Group B. The mean values of potassium and chloride levels were normal in both groups at the end of the shock period. Conclusion: Giving plasma during the first 12 hours of the burn shock period when the capillary leakage is maximum has no significant benefit. The plasma usage can be reduced by 50% compared to the use of the Muir and Barclay Formula from the beginning of the shock period with reduction of the costs and the possibility of transmission of undetected pathogens by nearly the same value if crystalloids are given during the first 12 hours of burns shock period. The use of isotonic normal saline during the first 12 hours appears more appropriate as it maintains adequate sodium balance to correct the hyponatraemia and at the same time prevents elevation of the serum potassium during the period when potassium is released from the cells. In addition, it does not have a significant reduction on the level of the serum proteins.
文摘Selection of proper reference genes (RGs) is an essential step needed for accurate normalization of results from genomic studies. Expression of RGs is regulated by many factors such as species, age, gender, type of tissue, the presence of disease, and the administration of therapeutic treatment. The aim of the present study was to identify optimal RGs in a set of blood samples collected at different time points (0, 24, 48, 72 h) from horses following administration of extracorporeal shock wave therapy (ESWT). The mRNA expression of twelve RGs: HPRT1, ACTB, HSP90A, SDHA, GUSB, B2M, UBC, NONO, TBP, H6PD, RPL32, GAPDH was determined using real time quantitative polymerase chain reaction (qPCR). An SAS program developed on the algorithm of geNorm, SASqPCR, was used to determine stability of the expression and the number of optimal RGs. The results showed that the range of quantification cycle (Cq) values of the evaluated genes varied between 17 and 26 cycles, and that one optimal RG, ACTB, was sufficient for normalization of gene expression. Results of stability of expression demonstrated that ACTB was the optimal choice for all the samples studied. Notably, in samples collected at 72 h post ESWT, TBP showed a significant change in the expression level, and was not suitable for use as a RG. These results substantiate the importance of validating and selecting an appropriate RG.
