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Background: Chronic kidney disease (CKD) is a public health problem that increases the risk of cardiovascular morbidity and mortality. Heart failure with preserved ejection fraction characterized by left ventricular hypertrophy (LVH) and diastolic dysfunction is a common cardiovascular complication of CKD. Anaemia is present in both dialysis & non dialysis CKD patients. Anaemia causes left ventricular hypertrophy (LVH) which in turn leads to increases morbidity and mortality in CKD, even before progression of chronic kidney disease (CKD) to end stage renal disease (ESRD). Our study is aimed at to evaluate the prevalence of left ventricular hypertrophy (LVH) and its correlation with anaemia in hospitalized CKD patients. Materials and Methods: A cross-sectional study was done on 50 patients of different stages of CKD admitted in the chittagong medical college hospital (CMCH). All the clinical data were reviewed and recorded. Data was analyzed by SPSS-18 and p value <0.05 was considered statistically significant. Journal of Bangladesh College of Physicians and Surgeons Vol. 42, No. 1, January 2024 Results: Majority of study population 64% was male, 36% was female. Most of the male patient (40%) of the study population were having abnormal left ventricular mass index (>130 gm/m²). More patients with severe left ventricular hypertrophy were found in stage 5 of CKD in female and male which was 8 and 23 respectively. Regarding correlation of Hb% with LVMI there was a significant negative correlation was found (r= -0.420, p = 0.003) between them means if Hb% decreases LVMI level increases. It was also found in male and female patients separately (for male r = -0.778, p = 0.001 and for female r = -0.746, p = 0.001). Conclusion: Anemia is widely prevalent in our CKD patients. Severity of anemia is correlated to left ventricular hypertrophy in these patients. Hence correction of anemia early in these group of patients can halt or prevent cardiovascular morbidity and mortality. [ABSTRACT FROM AUTHOR]

• Stack-based thermal resistance network model developed for micro channel heat exchangers. • Correlations developed with straight, sinusoidal and zigzag channels for sCO 2 recuperator. • Hybrid model demonstrates that 20 rows are sufficient to attain the correct stack performance. • Several combinations of stack dimensions generated for different channel configurations. • Sinusoidal channel offered least pressure drop and stack volume compared to straight and zigzag channels. In this work, a full-scale Thermal Resistance Network (TRN) coupled with a unit-cell-based CFD model identified as the hybrid model is developed and implemented in designing a Mini Channel Heat Exchanger (MCHE) as a recuperator used in sCO 2 Brayton power block. The TRN framework converts the MCHE domains into a thermal circuit using resistances and advection currents that can be used to model the entire stack with varying thermo-physical properties of working fluids. The results from the TRN model with CFD-based heat transfer and pressure drop correlations developed for different channel lengths, are compared with the original CFD data to ascertain the lowest possible channel length for precise correlation development. An appropriate channel length is further used for deriving correlations for sinusoidal and zigzag flow paths. The hybrid model helps determine the upper limit of the side width (fin width) of the channels based on equivalent thermal resistance between fluid and walls as the lower limit is constrained by stress criteria. The present model estimates that at least 20 rows/plates need to be modelled for the correct performance estimation of a full-scale MCHE. The minimum rate of heat loss-based stack optimization approach is implemented in estimating the optimum number of rows and stack dimensions. The channel and stack dimensions are obtained and compared for straight, sinusoidal, and zigzag flow paths for Reynolds numbers ranging from 5 × 103 to 20 × 103, ensuring a temperature pinch of 5 °C at the cold inlet. For cold inlet Reynolds number and channel diameter of 1.5 × 104 and 1.5 mm, the stack volumes for straight, zigzag, and sinusoidal channels are 1.8 m3, 1.21 m3, and 1.15 m3, respectively with sinusoidal and zigzag paths resulting in almost similar pressure drop as ∼110 Pa, 27% lower compared to the straight channel. The article presents a guideline for hybrid model implementation in designing mini/micro channel heat exchangers. [ABSTRACT FROM AUTHOR]